Charge controlling agent composition and electrophotographic toner

Abstract

 A charge controlling agent composition is disclosed, which comprises a quaternary ammonium salt and one or more inorganic pigments selected from the group consisting of barium sulfate, magnesium hydroxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, zinc silicate, calcium silicate, aluminum silicate, magnesium silicate and magnesium hydrogenphosphate. An electrophotographic toner containing the charge controlling agent composition is also disclosed.

Description

FIELD OF THE INVENTION

[0001] This invention relates to a charge controlling agent composition useful for toners which are electrophotographic developers. It also relates to an electrophotographic toner containing the composition.

BACKGROUND OF THE INVENTION

[0002] In an image formation process of electrophotography, an electrostatic latent image is formed on an inorganic photoconductive material composed of selenium, a selenium alloy, cadmium sulfide, amorphous silicone or the like or an organic photoconductive material using a charge generating agent and a charge transfer agent, developed with a toner, and then the developed image is transferred to paper or a plastic film, followed by fixing to give a visible image.

[0003] The photoconductive material has positive electrification property or a negative electrification property according to its construction. When an image part is remained as an electrostatic latent image, the image is developed with a toner of the opposite charge. On the other hand, when charge of an image part is removed to conduct reversal development, the image is developed with a toner of the equal charge. Toners are composed of a binder resin, a colorant, and other additives. Generally, a charge controlling agent is further added to the toners in order to impart a desirable friction electrification property (charge velocity, charge level, charge stability), a stability with the passage of time, or an environmental stability. Thus, the properties of the toners are greatly influenced by the charge controlling agent.

[0004] A two-component type toner is charged by the friction with a carrier, while a one-component type toner is charged by the friction with a sleeve. A latent image on the photoconductive material is developed with the toner thus charged.

[0005] Since the toner is consumed, the toner is always fed. However, the toner freshly fad is not charged, and hence a rise of charging to a predetermined level is made by stirring in a development zone and friction on sleeve. The amount of charge of the toner is often set to a value in the range of about 10 to 30 µC/g.

[0006] The control of the chargeability of the toner is the most important matter for the toner. The charging characteristics of the toner depend on the resin which is the principal component thereof. Usually, desired friction charging characteristics are obtained by using a charge controlling agent. There have been recently demanded more higher image quality, higher reliability and more speed-up. Closer charge control has been required in comparison with conventional charge control. Particularly, it has been highly demanded to develop a charge controlling agent which has a rapid rise of charging and is stable against environmental change and passage of time.

[0007] One of characteristics required for toners to carry out good development is how the toner freshly fed is made to rapidly rise to a predetermined amount of charge. When the toner is made to poorly rise, lowly charged toner is formed and not sufficiently transferred onto a photoreceptor and a lowering in density is caused. In addition, there are caused disadvantages that the toner is scattered, ground staining on duplicates is caused, copying machines are stained and the deterioration of developers is expedited.

[0008] In the case of low-speed copying machine, the initial rise of charge quantity can be covered to a certain extent by stirring in the development zone. In the case of high-speed copying machine, however, a rapid rise of charging is required because the toner freshly fad is more rapidly transferred from the development zone onto the photoreceptor in proportion as the speed is increased. In the case of the one-component toner, the toner must be charged not by the friction between the toner and the carrier, but only by the friction between the toner and the sleeve. Accordingly, the rise in the one-component toner is more important than that in the two-component toner.

[0009] There has been conventionally proposed that quaternary ammonium salts are used as charge controlling agents as disclosed in JP-A-62-53944 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-A-62-71968 and JP-A-62-3259. However, the proposed charge controlling agents do not have satisfactory compatibility with resins and are difficultly mixed with the resins in the preparation of the toners. Hence, there are many problems with regard to the characteristics of the toners.

[0010] It is very important that the charge controlling agents are uniformly dispersed in the resins in the preparation of the toners. When the charge controlling agents have poor dispersibility, the charge controlling agents can not be uniformly mixed with toner particles, the resulting toner particles are non-homogeneous in quality, a rise of charging is low, and the quality of the toner is liable to be changed with the passage of time. Toners obtained by using the proposed quaternary ammonium salts, etc. have problems in that charging is unstable under high temperature and humidity conditions, etc., and the proposed quaternary ammonium salts are not considered to be fully satisfying as charge controlling agents for toners.

[0011] Further, it is known that hardly water-soluble inorganic salts are internally added to the toners to prevent the toners from fusing onto the surface of metallic sleeve or the surface of the photoreceptor, to improve durability or to stabilize charging. For example, JP-A-58-91462 discloses a toner wherein barium sulfate is internally added. JP-A-1-200367 discloses a toner wherein tin oxide is internally added.

[0012] In the former toner, barium sulfate is apt to be agglomerated, and the effect obtained thereby is too low to improve various performances of the toner. The latter toner have problems in that when the toner is used over a long period of time, charging is lowered, which causes scattering of the toner and a defect in image.

[0013] Quaternary ammonium salt-modified polymers to be used as a charge controlling agent for a toner have been proposed. For example, JP-A-62-210472 discloses a copolymer of styrene with a methyl chloride-quaternized product of dimethylaminoethylmethacrylate, JP-A-58-162959 discloses a quaternary salt of a polymer of dialkylaminomethacrylamide, JP-A-59-189354 discloses a quaternary ammonium salt of a vinylpyridine copolymer, and JP-A-59-189351 discloses a quaternary ammonium salt of a dimethylaminomethacrylate copolymer.

[0014] However, these products have poor compatibility with the binder resin, thus they have a disadvantage that their dispersibility in toner are poor.

[0015] An attempt has been made to solve these problem by adding to the toner a small amount of fine particles of titanium oxide or abrasives as an external adding agent, as disclosed in JP-A-4-153660 and JP-A-63-318569.

[0016] However, since abrasive action of such external adding agents are too strong, they may cause undesirable wearing out of the photoreceptor upon cleaning of the toner. In addition, these external adding agent may transferred onto paper, which causes stain of the copied image.

[0017] Further, a toner comprising a composition obtained by adsorbing an unique fluorine surfactant onto silica gel is disclosed in JP-A-3-1162.

[0018] The present inventor have eagerly made studies to solve the above-described problems. As a result, the present inventors have found that a charge controlling agent composition, which is prepared from a specific quaternary ammonium salt as a charge controlling agent and a specific inorganic pigment and modified, has such a characteristics that the dispersibility of the composition in resins is very good. Further, the present inventors have ascertained that a toner obtained by using the thus-prepared charge controlling agent composition comprising a quaternary ammonium salt modified with an inorganic salt is freed from the above-described problems, namely, the toner can expedite the rise of charging, can improve the stability of the charging performance of thereof, can be prevented from being scattered and can prevent a defect in image from being caused. The present invention has been accomplished on the basis of this finding.

SUMMARY OF THE INVENTION

[0019] Accordingly, an object of the present invention is to provide a charge controlling agent composition of good performance which has a good rise of charging and is not affected by the change of temperatures and humidity even when development is repeatedly carried out continuously and moreover which can reproduce an image stable over a long period of time.

[0020] Another object of the present invention is to provide a toner in which charge controlling agent composition internally added.

[0021] Namely, the present invention relates to a charge controlling agent composition comprising a quaternary ammonium salt and a specific inorganic pigment.

[0022] Further, the present invention relates to an electrophotographic toner comprising the charge controlling agent composition.

BRIEF DESCRIPTION OF THE DRAWING

[0023] Fig. 1 is a graph illustrating a rise of tribo charge quantity of each of the toners obtained in Examples 1 to 3 and Comparative Example 2, wherein the abscissa axis represents a stirring (mixing) time with iron powder carrier, and the ordinate axis represents tribo charge quantity (µC/g).

DETAILED DESCRIPTION OF THE INVENTION

[0024] Now, the present invention will be illustrated in more detail below.

[0025] Preferred examples of the quaternary ammonium salt which can be used in the charge controlling agent composition of the present invention include quaternary ammonium salts represented by the following formulas (I) to (VII):


wherein R₁, R₂, R₃ and R₄ may be the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30; and X^⊖ represents an anion;


wherein R₅, R₆, R₇, R₈ and R₉ may be the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₅ and R₆ or R₇ and R₈ may be combined with each other to form an alicyclic or aromatic ring containing 6 to 30 carbon atoms;


wherein R₁₀ and R₁₁ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₁₁ may represent a hydrogen atom;


wherein R₁₂, R₁₃ and R₁₄ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; Y presents a carbon, oxygen or sulfur atom; and X^⊖ represents an anion; provided that R₁₃ and R₁₄ may be a hydrogen atom;


wherein R₁₅, R₁₆ and R₁₇ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₁₆ and R₁₇ may represent a hydrogen atom;


wherein R₁₈ and R₁₉ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; and


wherein R₂₀ represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30; and X^⊖ represents an anion.

[0026] In the above formulas (I) to (VII), X⁻ represents an anion such as an ion of a halogen atom (e.g., Cl⁻, Br⁻, I⁻), ClO₄⁻, BF₄⁻, PF₄⁻, sulfate ion, nitrate ion, borate ion, phosphate ion, an organic sulfate ion (e.g., methylsulfate ion), an organic phosphate ion (e.g., phenylphosphate ion), a carbonic acid ion (e.g., anions of acetic acid, benzoic acid, stearic acid and oleic acid), a tetraphenyl borate ion (e.g., anions of tetraphenyl borate, p-chlorotetraphenyl borate, p-methyltetraphenyl borate and tetranaphthyl borate), a cyanate ion (e.g., anions of zinc tetracyanate and zinc tetrathiocyanate), a phenolate ion (e.g., anions of phenol, p-chlorophenol and o-chlorophenol), a polyacid ion containing molybdenum or tungsten atom (e.g., anions of molybdenic acid, tungstic acid, and heteropolyacids containing molybdenum or tungsten atom), and an anion of an organic sulfonic acid such as those represented by the following formula (VIII) and (IX):


wherein m presents 1 or 2; n represents 0, 1 or 2; and R₂₁ may be the same or different when n is 2 and represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms, an aryl group containing 6 to 30 carbon atoms, an alkoxy group containing 1 to 30 carbon atoms, an aryloxy group containing 6 to 30 carbon atoms, hydroxy group or amino group each of which may have one or two of sulfonic acid group; provided that when n is 2, two R₂₁ groups may be combined with each other to form a heterocyclic, alicyclic or aromatic heterocyclic ring; and


wherein p represents 1 or 2; q and r each represents 0, 1 or 2; R₂₂ and R₂₃ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms, an aryl group containing 6 to 30 carbon atoms, an alkoxy group containing 1 to 30 carbon atoms, an aryloxy group containing 6 to 30 carbon atoms, hydroxy group or amino group each of which may have one or two of sulfonic acid group; provided that when q is 1 or 2 and r is 1 or 2, R₁ and R₂ may be combined with each other to form a heterocyclic, alicyclic or aromatic heterocyclic ring.

[0027] Further, oligomers having a quaternary ammonium salt group and polymers having a quaternary ammonium salt group can also be used as the quaternary ammonium salt.

[0028] Examples thereof include oligomers and polymers represented by the following formula (X):


wherein R₂₄ and R₂₅ may be the same or different and each represents an alkyl or alkoxy group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms, an aryl group containing 6 to 30 carbon atoms, or an aryloxy group containing 6 to 30 carbon atoms each of which may have an ether bond, a thioether bond, a carboxylic acid amide group, a sulfonic acid amide group, an urethane bond, a chloromethyl group, a nitro group, or a pyridinum group; R₂₆ represents a hydrogen atom or an alkyl group containing 1 to 10 carbon atoms; and s represents an integer of 2 to 100; provided that one of R₂₄ and R₂₅ has a quaternary ammonium salt group.

[0029] Further, quaternary ammonium salts of oligomers and polymers obtained from monomers selected from those represented by the following formulas (XI) to (XVI) are preferably used:


wherein R₂₇ represents an alkylene group containing 1 to 12 carbon atoms; and R₂₈ and R₂₉ independently represent a hydrogen atom or an alkyl group containing 1 to 30 carbon atoms;


wherein R₃₀ represents a hydrogen atom or a lower alkyl group;


wherein R₃₁, R₃₂, R₃₃ and R₃₄ independently represent a hydrogen atom or an alkyl group containing 1 to 20 carbon atoms;


wherein R₃₅ and R₃₆ independently represent a hydrogen atom or an alkyl group containing 1 to 10 carbon atoms; R₃₇ and R₃₈ independently represent a hydrogen atom, an alkyl group containing 1 to 20 carbon atoms or an aryl group; and R₃₉ represents an alkylene group containing 1 to 20 carbon atoms.

[0030] Examples of the inorganic pigment which can be used in the present invention include barium sulfate, magnesium hydroxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, zinc silicate, calcium silicate, aluminum silicate, magnesium silicate and magnesium hydrogenphosphate. These inorganic pigments may be coated with organic compounds, organic polymers, hydrophobic treating agents or titanate coupling agents.

[0031] The particle size of the inorganic pigment is preferably 25 µm or below. When the inorganic pigment is present in the form of secondary aggregations, the particle size of the aggregation may be 25 µm or more.

[0032] The inorganic pigments may be any of synthetic products and natural pigments. Further, inorganic pigment-containing reaction mixtures (solutions) formed by reaction of inorganic compounds can be used.

[0033] For example, a mixture of barium sulfate and aluminum hydroxide obtained by reaction barium chloride with aluminum sulfate and an alkali, a mixture of zinc carbonate and sodium sulfate obtained by reacting sodium carbonate with zinc sulfate, calcium carbonate obtained by reacting sodium carbonate with calcium chloride, or calcium sulfate obtained by reacting sodium sulfate with calcium chloride can be used.

[0034] The charge controlling agent composition of the present invention is prepared from the aforesaid quaternary ammonium salt and the aforesaid inorganic pigment. Any methods can be employed to prepare the charge controlling agent composition from the quaternary ammonium salt and the inorganic pigment can be used so long as a homogeneous composition of them can be obtained.

[0035] The homogeneous composition may be either a composition comprising particles in which the quaternary ammonium salt and the inorganic pigment are contained, or a composition comprising particles of the quaternary ammonium salt on which the inorganic pigment uniformly adheres.

[0036] The particles in which the quaternary ammonium salt and the inorganic pigment are contained is preferably prepared by adding the inorganic pigment or inorganic compounds which form the inorganic pigment at any one stage during the preparation of the quaternary ammonium salt, separating the resulting quaternary ammonium salt containing the inorganic pigment, then drying the quaternary ammonium salt.

[0037] In this instance, it is preferred that the inorganic pigment is, or the inorganic compounds which form the inorganic pigment are, allowed to exist together with starting compounds in a reaction system for preparing the quaternary ammonium salt.

[0038] As the inorganic compounds which form the inorganic pigment, those mentioned above can be used.

[0039] Further, the inorganic pigment may be added to a reaction mixture which is transferred from reaction step for the formation of the quaternary ammonium salt to purification step therefor, or it may be added to a wet filter cake obtained in the purification step.

[0040] Furthermore, the particles in which the quaternary ammonium salt and the inorganic pigment are contained can be prepared by mixing the dried quaternary ammonium salt and the inorganic pigment in the presence of an appropriate solvent, and then drying the resulting mixture. In this instance, the mixing of the quaternary ammonium salt and the inorganic pigment can be effected by kneading them in the presence of a slight amount of the solvent, or by preparing a slurry comprising the quaternary ammonium salt, the inorganic pigment and the solvent and stirring the slurry. The solvent may be water, an organic solvent, or a mixture of water and an organic solvent. Preferred examples of the organic solvent include alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and MIBK (methyl isobutyl ketone); dimethylformaldehyde and dimethylsulfonamide.

[0041] Alternatively, the particles of the quaternary ammonium salt on which the inorganic pigment uniformly adheres can be prepared by mechanically mixing and stirring the dried quaternary ammonium salt and the inorganic pigment so as to adhere the inorganic pigment uniformly onto the surface of the particles of the quaternary ammonium salt. As means for mixing, a ball mill, a Henschel mixer, a speed kneader, and the like can be used.

[0042] The particles obtained in the afore-mentioned manners can be used as the charge controlling agent composition for the preparation of the toner as such. If desired, the particles may be further pulverized, classified, and then used.

[0043] The content of the inorganic pigment in the thus-obtained charge controlling agent composition is such an amount that the characteristics of the charge controlling agent composition as a charge controlling agent is not adversely affected. The weight ratio of the quaternary ammonium salt to the inorganic pigment in the charge controlling agent composition is preferably from 0.5 to 99.5, more preferably from 5 to 95.

[0044] The charge controlling agent composition of the present invention has good dispersibility in binder resins, and a toner obtained by using the charge controlling agent composition has a good rise of charging and is freed from the problems associated with conventional toner with regard to the unstable chargeability of the toner and the scattering of the toner even when the toner is used over a long period of time under a low temperature and humidity condition or a high temperature and humidity condition. Accordingly, a clear developed image can be obtained.

[0045] The toner of the present invention is prepared by mixing the aforesaid charge controlling agent composition according to the present invention with the other components.

[0046] In a general method for preparing a two-component type toner, a binder resin is placed into a Henschel mixer and then a colorant and a charge controlling agent are added thereto, followed by preliminary mixing. Subsequently, the resulting mixture is kneaded by means of an EXTRUDER generally at 150°C or below, and then the resulting product is pulverized and classified to give a toner having a particle size distribution ranging from 5 to 25 µm. On the other hand, a one-component type toner can be obtained in the aforementioned method except for that the colorant is replaced by a magnetic powder.

[0047] The toner of the present invention can be obtained in the aforementioned methods provided that the charge controlling agent composition of the present invention is used in place of the conventional charge controlling agent.

[0048] An amount of the charge controlling agent composition of the present invention in the toner is preferably from 0.1 to 15 % by weight, more preferably from 0.5 to 10 % by weight, based on the weight of the toner.

[0049] It is preferred that the charge controlling agent composition of the present invention is in the form particles having a particle size distribution ranging from 0.5 to 25 µm. It is also preferred that the quaternary ammonium salt is in the form of particles having a particle size distribution ranging from 0.5 to 25 µm.

[0050] The toner of the present invention comprises a binder resin and a colorant in addition to the charge controlling agent composition.

[0051] Examples of the binder resin which can preferably be used in the toner of the present invention include polymers of styrene and substituted styrenes such as polystyrene and polyvinyltoluene; styrene-substituted styrene copolymers; styrene-acrylic ester copolymers; styrene-methacrylic acid copolymers; styrene-acrylonitrile copolymers; polyvinyl chloride resins; polyethylene-silicone resins; polyesters; polyurethanes; polyamides; epoxy resins; modified rosins; phenolic resins; and waxes. In addition thereto, other materials which are conventionally used as binder resins for toners can also be used in the present invention.

[0052] Examples of the colorant which can be used in the present invention include C.I. Pigment Yellow-12, C.I. Solvent Yellow-18, C.I. Disperse Yellow-33, C.I. Pigment Red-122, C.I. Solvent Red-19, C.I. Pigment Blue-15, C.I. Pigment Black-1, C.I. Solvent Black-3, C.I. Solvent Black-22 and carbon black. In addition thereto, other materials which are conventionally used as colorants for toners can also be used in the present invention. The colorant is contained in the toner according to the present invention in an amount of preferably from 3 to 10 % by weight.

[0053] The mixing of the charge control agent composition and the other ingredient to give the toner of the present invention can be effected by melt-mixing the binder resin with 0.1 to 50 % by weight based on the binder resin of the charge controlling agent composition, solidifying the resulting mixture, coarsely crushing the solidified mixture by means of a crushing device such as a hammer mill, finely crushing the crushed particles by means of a jet mill crusher, and then classifying the finely crushed particles by means of an air stream classifier. Alternatively, it may be effected by adding a polymerization initiator to a monomer or a monomer mixture for the binder resin, adding the charge controlling agent composition to the mixture in an amount of 0.1 to 50 % by weight based on the weight of the monomer component, polymerizing the monomer component while suspending in water, and then recovering and drying the resulting toner. A dye or carbon black as the colorant may added during these steps.

[0054] The thus-prepared toner can be charged by an amount of charge suitable for carrying out the development of an electrostatic latent image by the friction between the toner and the carrier. Even when development is repeatedly carried out, the toner is not affected by the change of temperature and humidity, the charge quantity can be retained constantly, and the charge distribution is uniform and can be kept constant.

[0055] Examples of the carrier which can be used in the present invention include iron powder and carriers obtained by coating a magnetic core with a styrene-methyl methacrylate copolymer, a silicone resin, a mixed resin of a styrene-methyl methacrylate copolymer and a silicone resin or a tetrafluorostyrene resin.

[0056] The charge controlling agent composition of the present invention can provide excellent charging characteristics even when used in one-component developer containing a magnetic substance. Further, the charge controlling agent composition of the present invention can be used for capsule toners and polymerization toners.

[0057] Examples of magnetic materials which can be used as the magnetic substance include fine powders of metals such as iron, nickel and cobalt; alloys of metals such as iron, cobalt, copper, aluminum, nickel and zinc; metal oxides such as aluminum oxide, iron oxide and titanium oxide; ferrites of iron, manganese, nickel, cobalt and zinc; nitrides such as vanadium nitride and chromium nitride; carbides such as tungsten carbide and silicon carbide; and mixtures thereof.

[0058] Preferred examples of the magnetic substance include iron oxides such as magnetite, hematite and ferrite.

[0059] The present invention is further illustrated below by reference to the following preparation examples of the composition and the application examples thereof as the toner. However, the invention is not intended to be construed as being limited to these examples. In the following examples, the amounts, parts and ratios of the ingredients are by weight unless otherwise indicated.

EXAMPLE 1

Quaternary ammonium salt:

[0060] 

        (C₁₄H₂₉)₂N^⊕(CH₃)₂·1/4[Mo₈O₂₆]^4⊖   (Compound 1)



   There was dissolved 13.0 parts of N,N-dimethyl-N,N-ditetradecylammonium chloride in 100 parts of methanol. To the resulting solution, there was added 20 parts of aluminum hydroxide (2 µm). Subsequently, an aqueous solution composed of 10 parts of ammonium molybdate tetrahydrate and 60 parts of water was added thereto, and the mixture was stirred at 50°C. The precipitated white precipitate was recovered by filtration, thoroughly washed with water and dried to obtain Composition 1 composed of the quaternary ammonium salt and aluminum hydroxide (50:50).

[0061] Subsequently, 88 parts of a styrene-n-butyl methacrylate copolymer resin (Himer SBM-73 manufactured by Sanyo Kasei KK), 5 parts of low-molecular polypropylene (Viscol 550-P manufactured by Sanyo Kasei KK), 5 parts of carbon black (#44 manufactured by Mitsubishi Kasei Corporation) and 2 parts of Composition 1 were premixed in a mixer for 10 minutes, and then melt-kneaded by means of a hot roll mill at 120°C, followed by crushing and classifying to obtain a toner having a particle size of 5 to 25 µm.

[0062] Next, 3 parts of the toner was mixed with 97 parts of an iron powder carrier (TEFV 200/300 manufactured by Nippon Teppun KK) to prepare a developer. After the developer was stirred, tribo-charge quantity was measured by using a blow-off charge measuring machine (manufactured by Toshiba Chemical KK). Tribo charge quantities (µC/g) after stirring time for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours were 3.9, 5.5, 9.3, 10.0, 10.4, 10.3 and 10.3, respectively. Accordingly, a rise of charging in a short period to time was good, charge quantity reached nearly saturated charge quantity in 5 minutes, and the rise of charging was very good.

[0063] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not change, and neither toner scattering nor off-set occurred. Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained in the copying test under normal temperature and humidity conditions was obtained. Neither toner scattering nor off-set occurred.

EXAMPLE 2

[0064] There was dissolved 13.0 parts of N,N-dimethyl-N,N-ditetradecylammonium chloride in 100 parts of methanol. An aqueous solution composed of 100 parts of ammonium molybdate tetrahydrate and 60 parts of water was added thereto, and the mixture was stirred at 50°C. The produced quaternary ammonium salt (Compound 1) was recovered by filtration.

[0065] The resulting wet cake was dispersed in 100 parts of water with stirring at room temperature. Subsequently, 20 parts of the same aluminum hydroxide (2 µm) as that used in Example 1 was added thereto, and the mixture was stirred overnight. The product was recovered by filtration, thoroughly washed with water and dried to obtain Composition 2 composed of the quaternary ammonium salt (Compound 1) and aluminum hydroxide (50:50).

[0066] A toner was prepared in the same manner as in Example 1 except that Composition 2 was used in place of Composition 1. The tribo charge quantity of the toner was measured. As a result, it was found that, after stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, tribo charge quantities (µC/g) were 3.6, 4.9, 9.0, 9.6, 9.8, 9.9 and 10.2, respectively. Tribo charge quantity after stirring for 5 minutes was 94% of that after 2 hour-stirring. Thus, there was obtained a toner having good rise of charging in a short period of time.

The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the quality of the image was not changed, and neither toner scattering nor offset occurred. The toner was not affected under high temperature and humidity environmental conditions as well as under low temperature and humidity environmental conditions, and a good image quality was obtained.

EXAMPLE 3

[0067] The quaternary ammonium salt (Compound 1) was synthesized in the same manner as in Example 2, recovered by filtration and dried. Immediately after drying, the same aluminum hydroxide (2 µm) as that used in Example 1 was added thereto, and the mixture was pulverized to obtain Composition 3 composed of the quaternary ammonium salt and aluminum hydroxide (50:50).

[0068] A toner was prepared in the same manner as in Example 1 except that Composition 3 was used in place of Composition 1. Tribo charge quantity was measured. After stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, tribo charge quantities (µC/g) were 3.4, 4.8, 8.8, 9.3, 9.5, 9.6 and 10.3, respectively. The value measured after stirring for 5 minutes was 90.3% of that after 2 hours. There was obtained a toner having good rise of charging in a short period of time.

[0069] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred.

[0070] The continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained under normal temperature and humidity conditions was obtained. Neither toner scattering nor offset occurred.

COMPARATIVE EXAMPLE 1

[0071] One part of the quaternary ammonium salt (Compound 1) synthesized and dried in the same manner as in Example 2 was used, and a toner was prepared in the same manner as in Example 1 except that aluminum hydroxide was omitted. Tribo charge quantity was measured. After stirring of the developer for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, tribo charge quantities (µC/g) were 2.0, 2.8, 4.9, 6.5, 8.7, 9.2 and 10.0, respectively. Tribo charge quantity after stirring for 5 minutes was 65% of that after 2 hours. Hence, a rise of charging was very poor.

[0072] In the same manner as in Example 1, an image test was made. A clear image which was not fogged was obtained at the initial stage of running. However, after obtaining about 1,000 copies, an image which was fogged and not clear was obtained.

COMPARATIVE EXAMPLE 2

[0073] The quaternary ammonium salt (Compound 1) synthesized and dried in the same manner as in Example 2 was used, and a toner was prepared in the same manner as in Example 1 by using the following composition.

Styrene-n-butyl methacrylate copolymer resin (Himer SBM-73F manufactured by Sanyo Kasei KK)	88 parts
Low-molecular polypropylene (VISCOL 550-P manufactured by Sanyo Kasei KK)	5 parts
Carbon black (#44 manufactured by Mitsubishi Kasei Corporation)	5 parts
Quaternary ammonium salt (Compound 1)	1 part
Aluminum hydroxide (2 µm)	1 part

[0074] In the same manner as in Example 1, a developer was prepared by using the resulting toner. After stirring with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, tribo charge quantities (µC/g) were 2.0, 3.0, 5.3, 7.0, 9.0, 9.5 and 10.4, respectively. Tribo charge quantity after stirring for 5 minutes was 67% of that after 2 hours. Hence, a rise of charging was poor.

[0075] In the same manner as in Example 1, an image test was carried out. A clear image which was not fogged was obtained at the initial stage of running. However, after obtained about 1,000 copies, an image which was fogged and not clear was obtained.

[0076] Fig. 1 is a graph illustrating a rise of tribo charge quality of each of the toners obtained in Examples 1 to 3 and Comparative Example 2, wherein the abscissa axis represents a stirring time (mixing time) of the toner with iron powder carrier, and the ordinate axis represents tribo charge quantity (µC/g). It can be seen from these results that the toners containing the charge controlling agent composition of the present invention are very excellent in a rise of charging.

[0077] It is important that the toner and the carrier are uniformly dispersed in each other in a short period of time to obtain a rapid rise characteristics of charging. A dispersed state after the stirring of each of the toners of Examples 1 to 3 and Comparative Examples 1 and 2 for 30 seconds was visually observed. Further, a developer was prepared by blending 3 parts of the toner with 97 parts of the carrier (iron powder carrier TEFV 200/300 manufactured by Nippon Teppun KK), and an image was copied by using a copying machine.

[0078] The toners containing the charge controlling agent composition of the present invention prepared in Examples 1 to 3 showed that the dispersed state of the toner and the carrier was nearly uniform, while the dispersed state of the toners of Comparative Examples 1 and 2 were speckled and non-uniform. When the toners of Examples 1 to 3 were dispersed, the dispersion of the toner and the carrier in each other could be attained in a short period of time, resulting in an excellent rise of charging as shown in Fig. 1. Further, the toners of Examples 1 to 3 gave a good image which had a good image quality and scarcely suffered from ground fog. The results are thought to be due to the charging characteristics obtained by a difference in the dispersed state of the quaternary ammonium salt and the inorganic pigment.

EXAMPLE 4

[0079] Composition 4 was prepared in the same manner as in Example 1 except that aluminum hydroxide (30 µm) was used in place of aluminum hydroxide (2 µm). A toner was prepared in the same manner as in Example 1 except that Composition 4 was used in place of Composition 1. The tribo charge quantity of the toner was measured. After the mixing of the toner with the carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, tribo charge quantities (µC/g) were 3.8, 5.6, 9.2, 9.9, 10.1, 10.2 and 10.2, respectively. The value after stirring for 5 minutes was 97.0% of that after 2 hours, and hence a rise of charging was good.

[0080] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred.

[0081] Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained by conducting copying under normal temperature and humidity conditions was obtained. Further, neither toner scattering nor offset occurred.

EXAMPLES 5 TO 19 AND COMPARATIVE EXAMPLES 3 TO 17

[0082] Compositions 5 to 30 containing quaternary ammonium salts indicated in Table 1 were prepared in the same manner as in Example 1 and used in Examples 5 to 19 shown in Table 2.

[0083] In the same manner as in Comparative Example 2, toners were prepared in Comparative Examples 3 to 17 shown in Table 3.

[0084] The results are shown in Tables 2 and 3. Binder resins, charge quantity-measuring method and the criterion of each evaluation item in Tables 2 and 3 are as follows.
Binder resins used in the preparation of toners:

A:

Styrene-acrylic acid copolymer (Himer SBM-73 manufactured by Sanyo Kasei KK)

B:

Styrene-acrylic acid copolymer (Himer TB-1000 manufactured by Sanyo Kasei KK)

C:

Polyester (HP-313 manufactured by Nippon Gosei Kagaku KK)

D:

Polyester (HP-320 manufactured by Nippon Gosei Kagaku KK)

E:

Polystyrene (average molecular weight: 1500)

Charge quantity:

Value measured after stirring for 2 hours.

Criterion:

The mark  ⃝ means that there is practically no problem.
The mark X means that there is practically a problem.

EXAMPLE 20

[0085] There was dissolved 6.24 parts of N,N,N-tri-n-butyl-N-benzylammonium chloride in 100 parts of methanol. To the resulting solution, there was added 3.0 parts of calcium carbonate (1.5 µm). Subsequently, an aqueous solution composed of 7.65 parts of sodium 1,7-dihydroxynaphthalene-3-sulfonate and 100 parts of water was added thereto. The mixture was stirred at 50°C for 2 hours. The precipitated white precipitate was recovered by filtration, thoroughly washed with water and dried to obtain Composition 31 composed of the quaternary ammonium salt and calcium carbonate (75:25).

[0086] A toner was prepared in the same manner as in Example 1 except that Composition 31 was used in place of Composition 1. The tribo charge quantity of the toner was measured.

[0087] After stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 3.0, 4.2, 7.0, 9.0, 9.1, 9.2 and 9.3, respectively. The value after 5 minutes was 96.8% of that after 2 hours. Accordingly, a rise of charging was good.

[0088] The toner was put into the development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred.

[0089] Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained by conducting copying under normal temperature and humidity conditions was obtained. Neither toner scattering nor offset occurred.

EXAMPLE 21

Quaternary ammonium salt:

[0090] 

[0091] There was dissolved 6.24 parts of N,N,N-tri-n-butyl-N-benzylammonium chloride in 100 parts of methanol. Subsequently, an aqueous solution composed of 7.65 parts of sodium 1,7-dihydroxynaphthalene-3-sulfonate and 100 parts of water was added thereto. The mixture was stirred at 50°C for 2 hours. The resulting quaternary ammonium salt (Compound 27) was recovered by filtration, and the wet cake was dispersed in 100 parts of water with stirring at room temperature. To the dispersion, there was added 3.0 parts of the same calcium carbonate (1.5 µm) as that used in Example 20. The mixture was stirred overnight. The product was recovered by filtration, thoroughly washed with water and dried to obtain Composition 32 having the same composition ratio as that of Composition 31.

[0092] A toner was prepared in the same manner as in Example 1 except that Composition 32 was used in place of Composition 1. The tribo charge quantity of the toner was measured.

[0093] After stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 2.8, 4.0, 6.3, 8.7, 9.0, 9.1 and 9.2, respectively. The value after 5 minutes was 94.6% of that after 2 hours. Accordingly, a rise of charging was good.

[0094] The toner was put into a development device, and continuous copying was carried out to make image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not charged, and neither toner scattering nor offset occurred.

[0095] Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained by conducting copying under normal temperature and humidity conditions was obtained. Neither toner scattering nor offset occurred.

EXAMPLE 22

[0096] The quaternary ammonium salt (Compound 27) synthesized in the same manner as in Example 22 was recovered by filtration, thoroughly washed with water and dried. Immediately after drying, the same calcium carbonate (1.5 µm) as that used in Example 20 was mixed with the salt. The mixture was pulverized in a pulverizer to obtain Composition 33 composed of the quaternary ammonium salt and calcium carbonate (75:25).

[0097] A toner was prepared in the same manner as in Example 1 except that Composition 33 was used in place of Composition 1. The tribo charge quantity of the toner was measured.

[0098] After stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantity (µC/g) were 2.6, 3.8, 6.0, 8.5, 8.8, 8.9 and 9.3, respectively.

[0099] The value after 5 minutes was 91.4% of that after 2 hours. Accordingly, a rise of charging was good.

[0100] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred.

[0101] Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained by conducting copying under normal temperature and humidity conditions was obtained. Neither toner scattering nor offset occurred.

COMPARATIVE EXAMPLE 18

[0102] One part of the quaternary ammonium salt (Compound 27) synthesized and dried in the same manner as in Example 21 was used, and a toner was prepared in the same manner as in Example 1 except that aluminum hydroxide was omitted. The tribo charge quantity of the toner was measured.

[0103] After stirring of toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes and 2 hours, the tribo charge quantities (µC/g) were 2.0, 3.1, 5.2, 5.8, 7.0, 8.0 and 9.0, respectively. The value after 5 minutes was 64.4% of that after 2 hours. Hence, a rise of charging was poor.

[0104] An image test was made in the same manner as in Example 1. A clear image which was not fogged was obtained at the initial stage of running. However, after obtaining about 1,000 copies, an image which was fogged and not clear was obtained.

COMPARATIVE EXAMPLE 19

[0105] A toner was prepared in the same manner as in Example 1 by using the quaternary ammonium salt (Compound 27) synthesized and dried in the same manner as in Example 21 and the following composition.

Styrene-n-butyl methacrylate copolymer resin (Himer SBM-73F manufactured by Sanyo Kasei KK)	88 parts
Low-molecular polypropylene (VISCOL 550-P manufactured by Sanyo Kasei KK)	5 parts
Carbon black (#44 manufactured by Mitsubishi Kasei Corporation)	5 parts
Quaternary ammonium salt (Compound 27)	1 part
Calcium carbonate (1.5 µm)	1 part

[0106] The tribo charge quantity of the resulting toner was measured. After stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes and 2 hours, the tribo charge quantities (µC/g) were 2.1, 3.3, 5.3, 6.0, 7.7, 8.0 and 9.2, respectively. The value after 5 minutes was 65.2% of that after 2 hours. Hence, the toner had a poor rise of charging.

[0107] In the same manner as in Example 1, an image test was carried out. A clear image which was not fogged was obtained at the initial stage of running. However, after obtaining about 1,000 copies, an image which was fogged and not clear was obtained.

EXAMPLES 23 TO 46, AND COMPARATIVE EXAMPLES 20 TO 43

[0108] Compositions 34 to 68 indicated in Table 4 were prepared by adding inorganic pigments during the course of the preparation of the quaternary ammonium salt in the same manner as in Example 20, and used in Examples 23 to 46 shown in Table 5. Compositions were prepared in the same manner as in Comparative Example 19 by using the quaternary ammonium salt synthesized and dried in the same manner as in Example 21, and used in Comparative Examples 20 to 43 shown in Table 6. The results are shown in Tables 5 to 6.

[0109] Binder resins, charge quantity-measuring method and the criterion used in the Tables are as follows.
Binder resins used in the preparation of toners:

A:

styrene-acrylic acid copolymer (Himer SBM-73 manufactured by Sanyo Kasei KK)

B:

Styrene-acrylic acid copolymer (Himer TB-1000 manufactured by Sanyo Kasei KK)

C:

Polyester (HP-313 manufactured by Nippon Gosei Kagaku KK)

D:

Polyester (HP-320 manufactured by Nippon Gosei Kagaku KK)

E:

Polyester (average molecular weight: 1500)

Charge quantity:

Value measured after stirring for 2 hours.

Criterion:

The mark  ⃝ means that there is practically no problem.
The mark X means that there is practically a problem.

EXAMPLE 47

[0110] There was dissolved 20.0 parts of N,N-dimethyl-N,N-ditetradecylammonium chloride in 100 parts of methanol. To the resulting solution, there was added 8.2 parts of aluminum hydroxide (2 µm). Subsequently, a solution composed of 14.4 parts of sodium tetraphenylborate and 100 parts of methanol was added thereto. The mixture was stirred at 30°C. The precipitated white precipitate was recovered by filtration, thoroughly washed with water and dried to obtain Composition 69 composed of the quaternary ammonium salt and aluminum hydroxide (80:20).

[0111] A toner was prepared in the same manner as in Example 1 except that Composition 69 was used in place of Composition 1. The tribo charge quantity of the toner was measured. After stirring time for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 2.5, 4.0, 6.1, 8.8, 9.0, 9.2 and 9.3, respectively. The value after 5 minutes was 94.6% of that after 2 hours. Hence, a rise of charging was good.

[0112] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred.

[0113] Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained by conducting copying under normal temperature and humidity conditions was obtained. Neither toner scattering nor offset occurred.

EXAMPLE 48

Quaternary ammonium salt:

[0114] 

        (C₁₄H₂₉)₂(CH₃)₂N^⊕(C₆H₅)₄B^⊖   (Compound 63)



   There was dissolved 20.0 parts of N,N-dimethyl-N,N-ditetradecylammonium chloride in 100 parts of aqueous methanol. To the resulting solution, there was added a solution composed of 14.4 part of sodium tetraphenylborate and 100 parts of methanol. The mixture was stirred at 30°C. The resulting quaternary ammonium salt (Compound 63) was recovered by filtration.

[0115] The wet cake was dispersed in 100 parts of water with stirring at room temperature. Subsequently, 8.2 parts of the same aluminum hydroxide (2 µm) as that used in Example 47 was added thereto. The mixture was stirred overnight. The product was recovered by filtration, thoroughly washed with water and dried to obtain Composition 70 composed of the quaternary ammonium salt (Compound 63) and aluminum hydroxide (80:20).

[0116] A toner was prepared in the same manner as in Example 1 except that Composition 70 was used in place of Composition 1. The tribo charge quantity of the toner was measured. After stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 2.3, 4.0, 5.4, 8.6, 8.9, 9.0 and 9.3, respectively. The tribo charge quantity after stirring for 5 minutes was 92.5% of that after 2 hours. Hence, there was obtained a toner having a good rise of charging in a short period of time.

[0117] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred. Further, the continuous copying test was carried out under high temperature and humidity conditions and under low temperature and humidity conditions. An image of good quality was obtained without being affected by environmental conditions.

EXAMPLE 49

[0118] The quaternary ammonium salt (Compound 63) synthesized in the same manner as in Example 48 was recovered by filtration and dried. Immediately after drying, the same aluminum hydroxide (2 µm) as that used in Example 47 was mixed with the salt. The mixture was pulverized in a pulverizer to obtain Composition 71 composed of the quaternary ammonium salt and aluminum hydroxide (80:20).

[0119] A toner was prepared in the same manner as in Example 1 except that Composition 71 was used in place of Composition 1. The tribo charge quantity of the toner was measured. After stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 2.4, 4.1, 5.6, 8.4, 8.8, 9.0 and 9.2, respectively. The value measured after stirring for 5 minutes was 91.3% of that after 2 hours. Hence, there was obtained a toner having a good rise of charging in a short period of time.

[0120] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred.

[0121] Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained by conducting copying under normal temperature and humidity conditions was obtained. Neither toner scattering nor offset occurred.

COMPARATIVE EXAMPLE 44

[0122] One part of the quaternary ammonium salt (Compound 63) synthesized and dried in the same manner as in Example 48 was used, and a toner was prepared in the same manner as in Example 1 except that aluminum hydroxide was omitted. The tribo charge quantity of the toner was measured. After stirring of the resulting developer for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 1.8, 3.0, 4.4, 6.0, 7.6, 8.6 and 9.4, respectively. The tribo charge quantity after stirring for 5 minutes was 63.8% of that after 2 hours. Hence, a rise of charging was very poor.

[0123] An image test was carried out in the same manner as in Example 1. A clear image which was not fogged was obtained at the initial stage of running. However, after obtaining about 1,000 copies, an image which was fogged and not clear was obtained.

COMPARATIVE EXAMPLE 45

[0124] A toner was prepared by using the quaternary ammonium salt (Compound 63) synthesized and dried in the same manner as in Example 48 and the following composition in the same manner as in Example 1.

Styrene-n-butyl methacrylate copolymer resin (Himer SBM-73F manufactured by Sanyo Kasei KK)	88 parts
Low-molecular polypropylene (VISCOL 550-P manufactured by Sanyo Kasei KK)	5 parts
Carbon black (#44 manufactured by Mitsubishi Kasei Corporation)	5 parts
Quaternary ammonium salt (Compound 63)	1 part
Aluminum hydroxide (2 µm)	1 part

[0125] A developer was prepared by using the resulting toner in the same manner as in Example 1. After stirring of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 1.9, 3.1, 4.8, 6.5, 7.8, 8.7 and 9.5, respectively. The tribo charge quantity after stirring for 5 minutes was 68.4% of that after 2 hours. Hence, a rise of charging was poor.

[0126] An image test was carried out in the same manner as in Example 1. A good image which was not fogged was obtained at the initial stage of running. However, after obtaining about 1,000 copies, an image which was fogged and not clear was obtained.

EXAMPLE 50

[0127] Composition 72 was prepared in the same manner as in Example 47 except that aluminum hydroxide (30 µm) was used in place of aluminum hydroxide (2 µm). A toner was prepared in the same manner as in Example 1 except that Composition 72 was used in place of Composition 1. The tribo charge quantity of the toner was measured. After the mixing of the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 2.6, 4.3, 6.3, 8.9, 9.0, 9.3 and 9.3, respectively. The value after stirring for 5 minutes was 95.7% of that after 2 hours. Hence, a rise of charging was good.

[0128] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred.

[0129] Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained by conducting copying under normal temperature and humidity conditions was obtained. Neither toner scattering nor offset occurred.

EXAMPLE 51

Quaternary ammonium salt:

[0130] 

        (C₁₄H₂₉)₂(CH₃)₂N^⊕·Br^⊖   (Compound 64)



   There were dissolved 12.5 parts of N,N-dimethyl-N-tetradecylamine and 20.0 parts of tetradecyl bromide in 100 parts of methanol. To the resulting solution, there was added 18.0 parts of calcium carbonate (1.5 µm). The mixture was stirred at 50°C. The precipitated white precipitate was recovered by filtration and dried to obtain Composition 73 composed of the quaternary ammonium salt and calcium carbonate (50:50).

[0131] A toner was prepared in the same manner as in Example 1 except that Composition 73 was used in place of Composition 1. The tribo charge quantity of the toner was measured. After stirring for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 3.3, 5.3, 7.2, 9.9, 10.1, 10.3 and 10.4, respectively. The value after stirring for 5 minutes was 95.2% of that after 2 hours. Hence, a rise of charging was good.

[0132] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred.

[0133] Further, the continuous copying test was carried out under high temperature and humidity conditions at 35°C and 85% RH and under low temperature and humidity conditions at 10°C and 30% RH. An image quality substantially equal to that obtained by conducting copying under normal temperature and humidity conditions was obtained. Neither toner scattering nor offset occurred.

EXAMPLE 52

[0134] There were dissolved 12.5 parts of N,N-dimethyl-N-tetradecylamine and 20.0 parts of tetradecyl bromide in 100 parts of methanol. The mixture was stirred at 50°C. The formed quaternary ammonium salt (Compound 64) was recovered by filtration.

[0135] The wet cake was dispersed in 60 parts of water with stirring at 10°C. Subsequently, 19 parts of the same calcium carbonate (1.5 µm) as that used in Example 51 was added thereto. The mixture was stirred overnight. The product was recovered by filtration, washed with water and dried to obtain Composition 74 composed of the quaternary ammonium salt (Compound 64) and calcium carbonate (50:50).

[0136] A toner was prepared in the same manner as in Example 1 except that Composition 74 was used in place of Composition 1. The tribo charge quantity of the toner was measured. After stirring the toner with an iron powder carrier for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 3.0, 5.0, 7.1, 9.5, 9.9, 10.2 and 10.3, respectively. The tribo charge quantity after stirring for 5 minutes was 92.2% of that after 2 hours. Hence, there was obtained a toner having a good rise of charging in a short period of time.

[0137] The toner was put into a development device, and continuous copying was carried out to make an image test. A good image was obtained at the initial stage of running. After obtaining 50,000 copies, the image quality was not changed, and neither toner scattering nor offset occurred. Further, the continuous copying test was carried out under high temperature and humidity conditions and under low temperature and humidity conditions. An image of good quality was obtained without being affected by environmental conditions.

COMPARATIVE EXAMPLE 46

[0138] A toner was prepared in the same manner as in Example 1 except that 1.0 part of the quaternary ammonium salt (Compound 64) synthesized and dried in the same manner as in Example 52 was used, water was not used and aluminum hydroxide was omitted. The tribo charge quantity of the toner was measured. After stirring the resulting developer for 30 seconds, one minute, 3 minutes, 5 minutes, 10 minutes, 30 minutes and 2 hours, the tribo charge quantities (µC/g) were 1.8, 3.0, 4.2, 5.3, 6.0, 6.8 and 7.3, respectively. The tribo charge quantity after stirring for 5 minutes was 72.6% of that after 2 hours. Hence, the toner had a very poor rise of charging.

[0139] An image test was carried out in the same manner as in Example 1. A clear image which was not fogged was obtained at the initial stage of running. However, after obtaining about 1,000 copies, an image which was fogged and not clear was obtained.

EXAMPLES 53 TO 62 AND COMPARATIVE EXAMPLES 47 TO 56

[0140] Compositions 75 to 87 containing the quaternary ammonium salts indicated in Table 7 were prepared in the same manner as in Example 47 and used in Examples 53 to 62 shown in Table 8. Further, the quaternary ammonium salts were used in Comparative Examples 47 to 56 in the same manner as in Comparative Example 45. The results are shown in Tables 8 and 9.

[0141] Binder resins, charge quantity-measuring method and the criterion of the evaluation of each item used in Tables 8 and 9 are as follows.
Binder resins used in the preparation of toners:

A:

styrene-acrylic resin copolymer (Himer SBM-73 manufactured by Sanyo Kasei KK)

B:

Styrene-acrylic resin copolymer (Himer TB-1000 manufactured by Sanyo Kasei KK)

C:

Polyester (HP-313 manufactured by Nippon Gosei Kagaku KK)

D:

Polyester (HP-320 manufactured by Nippon Gosei Kagaku KK)

E:

Polystyrene (average molecular weight: 1500)

Charge quantity:

Value measured after stirring for 2 hours.

Criterion:

The mark  ⃝ means that there is practically no problem.
The mark X means that there is practically a problem.

[0142] It is seen from Examples and Comparative Examples that when the charge controlling agent composition according to the present invention, which comprises the quaternary ammonium salt and the inorganic pigment is used, the dispersibility of the quaternary ammonium salt having a charge controlling effect in the resin can be well-improved, and each toner particle has good charging characteristics, that is, a uniform charging level and excellent charge retention. As a result, the toner particles and the carrier can be dispersed in each other in a short period of time, a rise of charging becomes rapider, and copying speed can be increased, and at the same time, the life of the toner can be prolonged and the toner is scarcely affected by the change of environmental conditions due to the change of temperature and humidity.

[0143] While the present invention has been described in detail and with reference to specific embodiments thereof, it is apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and the scope of the present invention.

Claims

1. A charge controlling agent composition comprising a quaternary ammonium salt and an inorganic pigment selected from the group consisting of barium sulfate, magnesium hydroxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, zinc silicate, calcium silicate, aluminum silicate, magnesium silicate and magnesium hydrogenphosphate.

2. The charge controlling agent composition of claim 1, wherein the weight ratio of said quaternary ammonium salt to said inorganic pigment is from 0.5 to 99.5.

3. The charge controlling agent composition of claim 1, wherein said charge controlling agent composition is obtained by adding the inorganic pigment or inorganic compounds which form the inorganic pigment during the preparation of said quaternary ammonium salt, separating the resulting quaternary ammonium salt containing inorganic pigment, then drying the quaternary ammonium salt containing inorganic pigment.

4. The charge controlling agent composition of claim 1, wherein said charge controlling agent is prepared by mixing the quaternary ammonium salt and the inorganic pigment in the presence of a solvent, and then drying the resulting mixture.

5. The charge controlling agent composition of claim 1, wherein said charge controlling agent is prepared by mixing and stirring the quaternary ammonium salt and the inorganic pigment so as to uniformly adhere the inorganic pigment onto the particles of the quaternary ammonium salt.

6. The charge controlling agent composition of claim 1, wherein said quaternary ammonium salt is selected from the following compounds presented by the following formulas (I) to (VII):

wherein R₁, R₂, R₃ and R₄ may be the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30; and X^⊖ represents an anion;

wherein R₅, R₆, R₇, R₈ and R₉ may be the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₅ and R₆ or R₇ and R₈ may be combined with each other to form an alicyclic or aromatic ring containing 6 to 30 carbon atoms;

wherein R₁₀ and R₁₁ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₁₁ may represent a hydrogen atom;

wherein R₁₂, R₁₃ and R₁₄ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; Y presents a carbon, oxygen or sulfur atom; and X^⊖ represents an anion; provided that R₁₃ and R₁₄ may be a hydrogen atom;

wherein R₁₅, R₁₆ and R₁₇ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₁₆ and R₁₇ may represent a hydrogen atom;

wherein R₁₈ and R₁₉ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; and

wherein R₂₀ represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30; and X^⊖ represents an anion; and wherein said anion is an ion of a halogen atom, ClO₄⁻, BF₄⁻, PF₄⁻, sulfate ion, nitrate ion, borate ion, phosphate ion, an organic sulfate ion, an organic phosphate ion, a carbonic acid ion, a tetraphenyl borate ion, a cyanate ion, a phenolate ion, a polyacid ion containing molybdenum or tungsten atom, or an anion of an organic sulfonic acid.

7. An electrophotographic toner obtained by mixing a binder resin, a colorant, and a charge controlling agent composition comprising a quaternary ammonium salt and an inorganic pigment selected from the group consisting of barium sulfate, magnesium hydroxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, zinc silicate, calcium silicate, aluminum silicate, magnesium silicate and magnesium hydrogenphosphate.

8. The electrophotographic toner of claim 7, wherein said charge controlling agent composition is present in an amount of 0.1 to 15 % by weight in the electrophotographic toner.

9. The electrophotographic toner of claim 7, wherein the weight ratio of said quaternary ammonium salt to said inorganic pigment in said charge controlling agent composition is from 0.5 to 99.5.

10. The electrophotographic toner of claim 7, wherein said charge controlling agent composition is obtained by adding the inorganic pigment or inorganic compounds which forms the inorganic pigment during the preparation of said quaternary ammonium salt, separating the resulting quaternary ammonium salt containing inorganic pigment, then drying the quaternary ammonium salt containing inorganic pigment.

11. The electrophotographic toner of claim 7, wherein said charge controlling agent composition is prepared by mixing the quaternary ammonium salt and the inorganic pigment in the presence of a solvent, and then drying the resulting mixture.

12. The electrophotographic toner of claim 7, wherein said charge controlling agent composition is prepared by mixing and stirring the quaternary ammonium salt and the inorganic pigment so as to adhere the inorganic pigment onto the particles of the quaternary ammonium salt.

13. The electrophotographic toner of claim 7, wherein said quaternary ammonium salt is selected from the following compounds presented by the following formulas (I) to (VII):

wherein R₁, R₂, R₃ and R₄ may be the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30; and X^⊖ represents an anion;

wherein R₅, R₆, R₇, R₈ and R₉ may be the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₅ and R₆ or R₇ and R₈ may be combined with each other to form an alicyclic or aromatic ring containing 6 to 30 carbon atoms;

wherein R₁₀ and R₁₁ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₁₁ may represent a hydrogen atom;

wherein R₁₂, R₁₃ and R₁₄ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; Y presents a carbon, oxygen or sulfur atom; and X^⊖ represents an anion; provided that R₁₃ and R₁₄ may be a hydrogen atom;

wherein R₁₅, R₁₆ and R₁₇ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms each of which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; provided that R₁₆ and R₁₇ may represent a hydrogen atom;

wherein R₁₈ and R₁₉ may be the same or different and each represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30 carbon atoms; and X^⊖ represents an anion; and

wherein R₂₀ represents an alkyl group containing 1 to 30 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms or an aryl group containing 6 to 30 carbon atoms which may have one or more members selected from the group consisting of an amino group, an ether bond, a thioether bond, an alkoxy group, a hydroxy group, a carbonic acid amide group, a sulfonamide group, an urethane bond, a chloromethyl group, a nitro group, an aromatic group containing 6 to 30 carbon atoms and an aromatic heterocyclic group containing 6 to 30; and X^⊖ represents an anion; and
wherein said anion is an ion of a halogen atom, ClO₄⁻, BF₄⁻, PF₄⁻, sulfate ion, nitrate ion, borate ion, phosphate ion, an organic sulfate ion, an organic phosphate ion, a carbonic acid ion, a tetraphenyl borate ion, a cyanate ion, a phenolate ion, a polyacid ion containing molybdenum or tungsten atom, or an anion of an organic sulfonic acid.

Drawing