[0001] The present invention relates to a porous ink jet recording element and a printing
method using the element.
[0002] In a typical ink jet recording or printing system, ink droplets are ejected from
a nozzle at high speed towards a recording element or medium to produce an image on
the medium. The ink droplets, or recording liquid, generally comprise a recording
agent, such as a dye or pigment, and a large amount of solvent. The solvent, or carrier
liquid, typically is made up of water, an organic material such as a monohydric alcohol,
a polyhydric alcohol or mixtures thereof.
[0003] An ink jet recording element typically comprises a support having on at least one
surface thereof at least one ink-receiving layer. The ink-receiving layer is typically
either a porous layer that imbibes the ink via capillary action, or a polymer layer
that swells to absorb the ink. Swellable hydrophilic polymer layers take an undesirably
long time to dry. Porous ink-receiving layers are usually composed of inorganic or
organic particles bonded together by a binder. The amount of particles in this type
of coating is often far above the critical particle volume concentration, which results
in high porosity in the coating. During the ink jet printing process, ink droplets
are rapidly absorbed into the coating through capillary action and the image is dry-to-touch
right after it comes out of the printer. Therefore, porous coatings allow a fast "drying"
of the ink and produces a smear-resistant image.
[0004] Ink jet prints, prepared by printing onto ink jet recording elements, are subject
to environmental degradation. They are especially vulnerable to damage resulting from
contact with water and atmospheric gases such as ozone. The damage resulting from
the post imaging contact with water can take the form of water spots resulting from
deglossing of the top coat, dye smearing due to unwanted dye diffusion, and even gross
dissolution of the image recording layer. Ozone bleaches ink jet dyes resulting in
loss of density. To overcome these deficiencies, ink jet prints are often laminated.
However, lamination is expensive as it requires a separate roll of material.
[0005] U.S. Patents 4,785,313 and 4,832,984 relate to an ink jet recording element comprising
a support having thereon a fusible, ink-transporting layer and an ink-retaining layer,
wherein the ink-retaining layer is non-porous. However, there is a problem with this
element in that it has poor image quality.
[0006] EP 858, 905A1 relates to an ink jet recording element having a porous, outermost
layer formed by heat sintering thermoplastic particles such as polyurethane which
may contain a slight amount of a hydrophilic binder such as poly(vinyl alcohol). However,
there is a problem with this element in that it has poor resistance to mechanical
abrasion when it does not contain a hydrophilic binder, and poor water-resistance
when it does contain a hydrophilic binder.
[0007] It is an object of this invention to provide an inkjet recording element having a
fusible protective uppermost layer and ink-retaining underlayer which can be printed
with ink jet inks without bleed. It is another object of the invention to provide
a porous ink-transporting layer that has good mechanical integrity and is abrasion
resistant. It is another object of the invention to provide a protective uppermost
ink-transporting layer that is thermally fusible and thereby can be rendered water
resistant. It is another object to provide an inkjet recording element that can be
thermally fused to provide high density of the printed image.
[0008] Another object of the invention is to provide a printing method using the above-described
element.
[0009] These and other objects are achieved in accordance with the invention which comprises
an ink jet recording element comprising a support having thereon in order:
a) at least one porous, ink-retaining layer; and
b) a fusible, porous ink-transporting layer comprising fusible, polymeric particles
and a film-forming, hydrophobic binder.
[0010] By use of the invention, a porous ink jet recording element is obtained that has
good abrasion resistance, and which when printed with an ink jet ink, and subsequently
fused, has good water-resistance and high print density.
[0011] Another embodiment of the invention relates to an ink jet printing method comprising
the steps of:
I) providing an ink jet printer that is responsive to digital data signals;
II) loading the printer with the ink jet recording element described above;
III) loading the printer with an ink jet ink composition;
IV) printing on the image-receiving layer using the ink jet ink composition in response
to the digital data signals; and
V) fusing the fusible, porous ink-transporting layer to provide a continuous polymeric
layer on the surface of the ink jet recording element.
[0012] The fusible, polymeric particles employed in the invention may have any particle
size provided they will form a porous layer. In a preferred embodiment of the invention,
the particle size of the fusible, polymeric particles may range from 0.5 to 10 µm.
The particle may be formed from any polymer which is fusible, i.e., capable of being
converted from discrete particles into a continuous layer through the application
of heat and/or pressure. In a preferred embodiment of the invention, the fusible,
polymeric particle comprises a condensation polymer, a styrenic polymer, a vinyl polymer,
an ethylene-vinyl chloride copolymer, a polyacrylate, poly(vinyl acetate), poly(vinylidene
chloride), a vinyl acetate-vinyl chloride copolymer. In still another preferred embodiment,
the condensation polymer may be a polyester or polyurethane.
[0013] The film-forming, hydrophobic binder useful in the invention can be any film-forming
hydrophobic polymer capable of being dispersed in water. In a preferred embodiment
of the invention, the hydrophobic binder is an aqueous dispersion of an acrylic polymer
or a polyurethane.
[0014] The particle-to-binder ratio of the particles and binder employed in the ink-transporting
layer can range between 98:2 and 60:40, preferably between 95:5 and 80:20. In general,
a layer having particle-to-binder ratios above the range stated will usually not have
sufficient cohesive strength; and a layer having particle-to-binder ratios below the
range stated will usually not be sufficiently porous to provide good image quality.
[0015] In a preferred embodiment of the invention, the ratio of the mean volume weighted
size of the dispersed film forming hydrophobic polymeric binder particles to the fusible,
polymeric particles is preferably 0.15 to 1, and more preferably greater than 0.41
to 1, as determined by a Horiba LA-920 Laser Scattering Particle Size Distribution
Analyzer (Horiba Instruments, Inc.). While not being bound by any theory, it is believed
that if the ratio is below the lower limit stated, the binder particles pass through
the interparticle voids between the larger fusible particles, and deposit at the interface
with the ink-retaining layer. The resultant structure blocks ink flow into the ink-retaining
layer, resulting in undesirable bleed. The interparticle voids are taken to be the
radius in the plane of contact of the interstice, r, formed by three spheres of radius,
R. In a close packed array, r = 0.15R, and in the more open array of square packed
spheres r = 0.41R.
[0016] The ink-retaining layer can be any porous structure, but it is preferred that the
mean pore radius is smaller than the uppermost ink-transporting layer. Thus, if the
ink-retaining layer is composed of particles and binder, the particles will be significantly
smaller than the fusible, polymeric particles in the upper ink-transporting layer,
thereby assuring a correct pore-size hierarchy.
[0017] In general, the ink-retaining layer or layers will have a thickness of 1 µm to 50
µm, and the top ink-transporting layer will usually have a thickness of 2 µm to 50
µm. In a preferred embodiment, the ink-retaining layer is present in an amount from
1 g/m
2 to 50 g/m
2, preferably from 5.0 g/m
2 to 30 g/m
2.
[0018] In a preferred embodiment of the invention, the ink-retaining layer is a continuous,
co-extensive porous layer which contains organic or inorganic particles. Examples
of organic particles which may be used include core/shell particles such as those
disclosed in U.S.S.N. 09/609,969 of Kapusniak et al., filed June 30, 2000, and homogeneous
particles such as those disclosed in U.S.S.N. 09/608,466 of Kapusniak et al., filed
June 30, 2000. Examples of organic particles which may be used include acrylic resins,
styrenic resins, cellulose derivatives, polyvinyl resins, ethylene-allyl copolymers
and polycondensation polymers such as polyesters. Examples of inorganic particles
which may be used in the ink-retaining layer of the invention include silica, alumina,
titanium dioxide, clay, calcium carbonate, barium sulfate, or zinc oxide.
[0019] In a preferred embodiment of the invention, the porous ink-retaining layer comprises
from 20 % to 100 % of particles and from 0 % to 80 % of a polymeric binder, preferably
from 80% to 95 % of particles and from 20 % to 5 % of a polymeric binder. The polymeric
binder may be a hydrophilic polymer such as poly(vinyl alcohol), poly(vinyl pyrrolidone),
gelatin, cellulose ethers, poly(oxazolines), poly(vinylacetamides), partially hydrolyzed
poly(vinyl acetate/vinyl alcohol), poly(acrylic acid), poly(acrylamide), poly(alkylene
oxide), sulfonated or phosphated polyesters and polystyrenes, casein, zein, albumin,
chitin, chitosan, dextran, pectin, collagen derivatives, collodian, agar-agar, arrowroot,
guar, carrageenan, tragacanth, xanthan, rhamsan and the like. Preferably, the hydrophilic
polymer is poly(vinyl alcohol), hydroxypropyl cellulose, hydroxypropyl methyl cellulose,
a poly(alkylene oxide), poly(vinyl pyrrolidinone), poly(vinyl acetate) or copolymers
thereof or gelatin.
[0020] Suitable porous materials for an ink-retaining layer include, for example, silica
or alumina in a polymeric binder. In a preferred embodiment, the ink-retaining layer
is porous fumed alumina in a crosslinked poly(vinyl alcohol) binder.
[0021] In order to impart mechanical durability to an ink jet recording element, crosslinkers
which act upon the binder discussed above may be added in small quantities. Such an
additive improves the cohesive strength of the layer. Crosslinkers such as carbodiimides,
polyfunctional aziridines, aldehydes, isocyanates, epoxides, polyvalent metal cations,
vinyl sulfones, pyridinium, pyridylium dication ether, methoxyalkyl melamines, triazines,
dioxane derivatives, chrom alum, zirconium sulfate and the like may be used. Preferably,
the crosslinker is an aldehyde, an acetal or a ketal, such as 2,3-dihydroxy-1,4-dioxane.
[0022] The porous ink-retaining layer can also comprise an open-pore polyolefin, an open-pore
polyester or an open pore membrane. An open pore membrane can be formed in accordance
with the known technique of phase inversion. Examples of a porous ink-receiving layer
comprising an open-pore membrane are disclosed in U.S.S.N. 09/626,752 and U.S.S.N.
09/626,883, both of Landry-Coltrain et al., filed July 27, 2000.
[0023] In another preferred embodiment of the invention, two porous, ink-retaining layers
are present. In this embodiment, the uppermost layer is substantially the same as
the lower layer, but at a thickness of only 1 % to 20 % of the thickness of the lower
layer, and also contains from 1-20 % by weight of a mordant, such as a cationic latex
mordant.
[0024] The two porous, ink-retaining layers can be coated simultaneously or sequentially
by any of the known coating techniques as noted below. The dye image is then concentrated
at the thin uppermost ink-retaining layer containing a mordant, and thereby enhances
print density.
[0025] The support used in the ink jet recording element of the invention may be opaque,
translucent, or transparent. There may be used, for example, plain papers, resin-coated
papers, various plastics including a polyester resin such as poly(ethylene terephthalate),
poly(ethylene naphthalate) and poly(ester diacetate), a polycarbonate resin, a fluorine
resin such as poly(tetra-fluoro ethylene), metal foil, vinyl, fabric, laminated or
coextruded supports, various glass materials, and the like. In a preferred embodiment,
the support is a resin-coated paper. The thickness of the support employed in the
invention can be from 12 to 500 µm, preferably from 75 to 300 µm.
[0026] If desired, in order to improve the adhesion of the base layer to the support, the
surface of the support may be corona-discharge-treated prior to applying the base
layer or solvent-absorbing layer to the support.
[0027] Since the image recording element may come in contact with other image recording
articles or the drive or transport mechanisms of image recording devices, additives
such as surfactants, lubricants, UV-absorbing agents, matte particles and the like
may be added to the element to the extent that they do not degrade the properties
of interest.
[0028] The layers described above, including the base layer and the top layer, may be coated
by conventional coating means onto a support material commonly used in this art. Coating
methods may include, but are not limited to, wound wire rod coating, slot coating,
slide hopper coating, gravure, curtain coating and the like. Some of these methods
allow for simultaneous coatings of both layers, which is preferred from a manufacturing
economic perspective.
[0029] After printing on the element of the invention, the fusible, porous ink-transporting
layer is heat and/or pressure fused to form an overcoat layer on the surface. Fusing
is preferably accomplished by contacting the surface of the element with a heat fusing
member, such as a fusing roller or fusing belt. Thus, for example, fusing can be accomplished
by passing the element through a pair of heated rollers, heated to a temperature of
60 °C to 160 °C, using a pressure of 5 to 15 MPa at a transport rate of 0.005 m/sec
to 0.5 m/sec.
[0030] Ink jet inks used to image the recording elements of the present invention are well-known
in the art. The ink compositions used in ink jet printing typically are liquid compositions
comprising a solvent or carrier liquid, dyes or pigments, humectants, organic solvents,
detergents, thickeners, preservatives, and the like. The solvent or carrier liquid
can be solely water or can be water mixed with other water-miscible solvents such
as polyhydric alcohols. Inks in which organic materials such as polyhydric alcohols
are the predominant carrier or solvent liquid may also be used. Particularly useful
are mixed solvents of water and polyhydric alcohols. The dyes used in such compositions
are typically water-soluble direct or acid type dyes. Such liquid compositions have
been described extensively in the prior art including, for example, U.S. Patents 4,381,946;
4,239,543 and 4,781,758.
[0031] The following examples further illustrate the invention.
Example 1
Synthesis of Polyurethane Polymer
[0032] In a 2 liter resin flask equipped with thermometer, stirrer, water condenser and
vacuum outlet, 123 g (0.041 mole) Polyester polyol, Tone® 0260, (Union Carbide Corp.),
Mw 3000, was melted and dewatered under vacuum at 90°C. The vacuum was released and
at 40°C there was then added 10.20 g (0.076 mole) 2,2- Bis(hydroxymethyl)propionic
acid, 128.76 g (0.383 mole) Hexafluorobisphenol A, 75 g of Reagent grade Ethyl Acetate,
and 20 drops of Dibutyltin Dilaurate (catalyst). The temperature was adjusted to 80°C
and the contents stirred for 30 minutes. The temperature was lowered to 70°C and while
stirring, 111.20 g (0.50 mole) of isophrone diisocyanate and 10 g ethyl acetate were
added. The temperature was raised to 80°C and reaction stirred at temperature until
completion which gave, upon cooling, a 60.6 weight percent solids solution. The solution
was used to prepare the polyurethane particles P1 described below.
Preparation of Polyurethane Particles - P1
[0033] To 194.8 g of the above 60.6 % weight percent solids polyurethane dissolved in ethyl
acetate described above was added 172.0 g of ethyl acetate and 4.0 g of triethanolamine.
A separate aqueous composition was prepared by mixing 26.8 g of ethyl acetate and
1202.4 g of deionized water. The organic composition was added slowly to the aqueous
composition using a low shear propeller mixing device. The resulting oil-in-water
emulsion was then subjected to a high shear Brinkman rotor-stator mixer for 5 minutes
at 5000 rpm. The ethyl acetate was removed by rotary evaporation under vacuum at 68°C
and the particles were concentrated to afford a 30 % solids dispersion of 2 µm particles.
Preparation of Polystyrene Particles - P2
[0034] To 333 g styrene was added 10 g 2,2'- azobis(2,4-dimethylvaleronitrile), Vazo 52®
(DuPont Corp.), and stirred until the Vazo 52 ® dissolved. Separately, an aqueous
phase was prepared by adding to 1000 g of distilled water, 10.43 g potassium hydrogen
phthalate, 4 g 0.1N HCl, 7.2 g poly(adipic acid-co-methylaminoethanol) and 91.5 g
of Ludox TM® colloidal silica, and stirring for 15 minutes. The organic phase was
then added to the stirred (marine prop agitator) aqueous phase and stirred for 15
minutes. The resultant dispersion was passed through a Gaulin homogenizer twice at
20.7 MPa and then heated at 54°C for sixteen hours. There was thereby obtained a narrowly
distributed population of 2 µm polystyrene particles.
Preparation of Coating Solutions for Ink-transporting Upper Layer
[0035] Coating solution S1 was prepared by adding to the P1 particles the hydrophobic binder,
B1, Witcobond ®W320, an aqueous dispersion of 1.9 polyurethane particles Tg = -12°C.
The coating solution at 20 % solids comprised 90 parts by weight P1 particle solids
and 10 parts by weight binder solids.
[0036] Coating solution S2 was prepared by adding to the P2 particles the same hydrophobic
binder. The solution at 20 % solids comprised 85 parts P2 particle solids and 15 parts
binder solids.
Preparation of Porous Ink-Retaining Lower Layers
[0037] A polyethylene resin-coated paper support was corona discharge treated. The support
was then hopper coated and force air dried at 60°C to provide the following ink-retaining
layers:
Layer L1- a 38 µm layer comprising 87 % fumed alumina, 9 % poly(vinyl alcohol), and 4 % dihydroxydioxane
crosslinking agent
Layer L2- a two layer structure comprising L1 and coated simultaneously on L1 a 2 µm layer
comprising 87 % fumed alumina, 8 % 100nm colloidal latex dispersion of divinylbenzene-co-N-
vinylbenzyl- N,N,N - trimethylammonium chloride, 6 % poly(vinyl alcohol), and 1 %
Zonyl ®FSN surfactant (Dupont Corp.).
Preparation of Control Non-Porous Hydrophilic Ink-Retaining Layers
[0038] Hydrophilic Layer L3 - an aqueous solution comprising 6.7 % gelatin, and 1.2 % poly(vinyl pyrrolidone),
K90 (International Specialty Products Co.) was hopper coated to provide an ink-retaining
layer of 8.6 g/m
2.
[0039] The following control layers were rod coated:
Hydrophilic Layer L4- an aqueous solution comprising 10% poly(vinyl pyrrolidone), K90 (International Specialty
Products Co.) was rod coated and air dried to provide a base layer of 8.0 g/m2;
Hydrophilic Layer L5- a layer comprising polyvinyl alcohol at 8.0 g/m2 was prepared in like fashion.
Element 1 of the Invention
[0040] The porous ink-transporting layer was prepared by separately coating solutions as
shown in Table 1 over the porous ink-retaining layers as shown in Table 1 using a
wire wound rod, calibrated to give a wet laydown of 40 µm and air dried.
Control Elements C-1 through C-4
[0041] These elements were prepared the same as Element 1 except using the solutions and
ink-retaining layers as shown in Table 1.
Control Elements C-5 through C-8
[0042] These elements were layers L2 through L5 without the ink-transporting layer.
Printing
[0043] A bleed test target was printed on the elements and controls with a Hewlett-Packard
Photosmart ® printer. The target design had seven adjacent 9 mm by 48 mm rectangular
bars, each bar was one of the primary or secondary subtractive color i.e. C,M,Y,R,G,B,K,
and in each bar was embedded six 7 mm squares of the other colors. So, for example,
the Cyan bar had embedded squares of M,Y,R,G,B,K.
Testing
[0044] The printed elements were then examined for bleed with the following evaluation standards:
5: No change in the shape of the embedded squares with sharp edges of the squares
maintained
3: The square pattern was slightly rounded with smooth edges
1: Major spreading and deformation of the rectangular pattern with ragged edges.
An evaluation of 5 or 3 is necessary for good image quality. The following results
were obtained:
Table 1
Element |
Solution |
Ink-Retaining Layer |
Bleed |
1 |
S1 |
L1 |
5 |
2 |
S1 |
L2 |
5 |
3 |
S2 |
L2 |
5 |
Control 1 |
S1 |
L3 |
1 |
Control 2 |
S1 |
L4 |
1 |
Control 3 |
S1 |
L5 |
1 |
Control 4 |
S2 |
L3 |
1 |
Control 5 |
- |
L2 |
5 |
Control 6 |
- |
L3 |
5 |
Control 7 |
- |
L4 |
5 |
Control 8 |
- |
L5 |
5 |
[0045] The above results show that the elements of the invention having a fusible, porous
ink-transporting uppermost layer and porous ink-retaining bottom layers have excellent
bleed performance, whereas the control elements having the same ink-transporting layer
over a non-porous hydrophilic ink-retaining layer have poor bleed performance which
is significantly worse than that of the hydrophilic layer alone.
Example 2
Preparation of Urethane Particles employed in the Invention
Particle P3
[0046] In a 2 liter resin flask equipped with thermometer, stirrer, water condenser and
a vacuum outlet, 107.5 g (0.125 mole) polycarbonate polyol PC 1733, Mw = 860, (Stahl
Co.) was melted and dewatered under vacuum at 100°C. The vacuum was released and then
at 40°C, 10.2 g (0.076 mole) dimethylol propionic acid, 100.52 g (0.299 mole) bisphenol
AF, and 75 g methyl ethyl ketone were added. Then 20 drops dibutyltin dilaurate (catalyst)
was added while stirring. The temperature was adjusted to 75°C and maintained until
a homogeneous reaction mixture was obtained. Slowly, 111.2 g (0.50 mole) isophorone
diisocyanate was added followed by 10 g methyl ethyl ketone. The temperature was raised
to 85°C and maintained until the isocyanate functionality was reduced to substantially
nil. While stirring, a stoichiometric amount of potassium hydroxide based on dimethylol
propionic acid was added, and maintained for 5 minutes. An amount of water 5 times
the amount of methyl ethyl ketone was added with rapid stirring to form a milky white
aqueous dispersion. The mean particle size was 6.1 µm as determined using a Horiba
LA-920 Particle Size Analyzer.
Binders
[0047] The following binders were employed in this Example for Elements of the Invention:
Hydrophobic Binder B1 Witcobond ® W320 an aqueous dispersion of 1.9 micron polyurethane particles Tg =
-12°C from Uniroyal Chemical Co.
Hydrophobic Binder B2 Witcobond ® W507 an aqueous dispersion of 1.9 micron polyurethane particles Tg =
-30°C from Uniroyal Chemical Co.
Hydrophobic Binder B3 Witcobond ® W290H an aqueous dispersion of 1.9 micron polyurethane particles Tg =
-44°C from Uniroyal Chemical Co.
[0048] The following binders were employed in this Example for Control Elements:
Hydrophilic Binder B4 - Methyl Cellulose A4M a water-soluble polymer from Dow Chemical Co.
Hydrophilic Binder B5- A water soluble polyvinyl alcohol from Nippon Gohsei Co.
Hydrophilic Binder B6- Limed ossein gelatin.
Elements 4-7 of the Invention
[0049] The porous ink-transporting layer was prepared by coating an 8.1% solids dispersion
comprised of 85 parts particles P3 and 15 parts hydrophobic binder B1. The dispersion
was coated with a 40 µm wire wound rod over the porous ink-retaining layer L2 described
in Example 1 to form Element 4. Elements 5-7 were similarly prepared from 20 % solids
dispersions comprised of 90 parts particles P1 and 10 parts hydrophobic binder in
the combinations given in the table below.
Control Elements C9 - C11
[0050] These elements were prepared by coating a 10 % solids dispersion comprised of 95
parts particles P3 and 10 parts hydrophilic binder B4 on the porous ink-retaining
layer L2. Controls 10 and 11 were similarly prepared and coated from 20 % solids dispersions
comprised of 90 parts particles P1 and 10 parts hydrophilic binders in the combinations
given in the table below.
Printing
[0051] A test target comprised was printed with a Hewlett-Packard Photosmaat ® printer.
The target consisted of seven sets of four 1 cm
2 color patches, a set in each of the primary and secondary colors and black. Each
patch was printed at a single density, the set ranging from 25 % to 100 % density
in equal steps.
Fusing and Testing
[0052] The printed elements and controls were fused in a heated nip at 150°C and 4.2 kg/cm
2 against a sol-gel coated polyimide belt at 63.5 cm/min. A water drop was placed on
each color patch of the fused print for 30 minutes and then blotted. Waterfastness
was judged by the transfer of dye to the blotter and density loss in the blotted color
patch on the following scale:
5 - no dye transfer to blotter and no density loss observable in the color patch.
1- heavy dye transfer to blotter and significant density loss in blotted color patch.
Table 2
Element |
Particles |
Binder |
Water Resistance |
4 |
P3 |
B1 |
5 |
5 |
P1 |
B1 |
5 |
6 |
P1 |
B2 |
5 |
7 |
P1 |
B3 |
5 |
Control 9 |
P3 |
B4 |
1 |
Control 10 |
P1 |
B5 |
1 |
Control 11 |
P1 |
B6 |
1 |
[0053] The above results show that the elements 4-7 of the invention with a hydrophobic
binder in the porous ink-transporter layer had excellent water resistance whereas
the controls with a hydrophilic binder in the ink-transporting layer have poor water
resistance.
Example 3
[0054] The following particles were used in this Example:
Particles P4 -prepared substantially as per P3 but neutralized with a stoichiometric amount of
triethanol amine and dispersed using Aerosol ®OT surfactant affording a particle size
3.8 microns.
Particles P5 - prepared substantially as per P 1 but with a particle size of 2.4 microns.
Particles P6 - prepared substantially as per P3 but neutralized with one half the stoichiometric
amount of KOH affording a particle size of 30 microns.
[0055] In addition to Binder B1, B2 and B3 described above, the following additional binders
were used in this Example:
Binder B7- Epocros® 2010 a commercially available acrylic latex obtained from Esprix Technologies
mean particle size 0.15 µm
Binder B8- Epocros ®2020 a commercially available acrylic latex obtained from Esprix Technologies
mean particle size 0.10 µm
Binder B9- Witcobond ®234 an aqueous dispersion of 0.10 micron polyurethane particles Tg =
-28°C.
Elements 8 -13 of the Invention
[0056] Aqueous 20 % solids dispersions were prepared from combinations of the above particles
and binders at 90 parts polyurethane particles and 10 parts binder particles in combinations
whose binder to particle size ratio was at least 0.15 and coated with a 40 µm wire
wound rod over the porous ink-retaining layer L2 from Example 1 to form elements of
the invention 8 -13, as shown in Table 3.
Controls C12 - C18
[0057] Controls C12 - C18 were prepared similar to Elements 8-13 except combinations of
particles and binder were chosen whose size ratio was less than 0.15. Control 1 had
no binder and Control 18 was Canon "HyperPhoto" media, a commercially available product
with a sintered ink-transporting layer, as shown in Table 3.
Testing
[0058] Abrasion resistance of the unfused coatings was tested by contacting the coatings
with a 2.5 by 8.0 cm strip of acid free 29.5 kg card stock black paper from Fiskars
Inc., and applying a 4.4 N force to the latter third of the strip while uniformly
transporting it across the coating. The test was evaluated by noting the density of
white powder transferred to the black paper strip according to the following criteria:
5- No transfer
3- Light transfer
1- Heavy transfer
[0059] A rating less than 3 is unacceptable for abrasion resistance. A bleed test target
was printed and the elements and controls were then fused as described in Example
2. The bleed target was evaluated as described in Example 1.
Table 3
Element |
Binder Size (µm) |
Particle Size (µm) |
B/P Size Ratio |
Bleed |
Abrasion |
8 |
B1 (1.9) |
P1 (3.8) |
0.5 |
5 |
5 |
9 |
B2 (1.0) |
P1 (3.8) |
0.26 |
3 |
5 |
10 |
B3 (1.1) |
P1 (3.8) |
0.29 |
3 |
5 |
11 |
B1 (1.9) |
P2 (2.4) |
0.79 |
5 |
5 |
12 |
B2 (1.0) |
P2 (2.4) |
0.41 |
5 |
5 |
13 |
B3 (1.1) |
P2 (2.4) |
0.49 |
5 |
5 |
Control 12 |
- |
P1 (3.8) |
0.0 |
5 |
1 |
Control 13 |
B7 (0.15) |
P1 (3.8) |
0.04 |
1 |
- |
Control 14 |
B8 (0.10) |
P1 (3.8) |
0.03 |
1 |
- |
Control 15 |
B9 (0.10) |
P1 (3.8) |
0.03 |
1 |
- |
Control 16 |
B9 (0.10) |
P2 (2.4) |
0.04 |
1 |
- |
Control 17 |
B1 (1.9) |
P6 (30) |
0.06 |
1 |
- |
Control 18 |
- |
(0.5) |
0.0 |
5 |
3 |
[0060] The above results show that Elements 8-13 of the invention exhibited little or no
bleed with good mechanical integrity whereas the control elements were deficient in
abrasion resistance.
Example 4
Particles
[0061] Urethane particles P1 from Example 1 were used.
Binders
[0062] Hydrophobic binders B1 - B3 from Example 2 were used.
Ink-Retaining Layers
[0063] The ink-retaining layers L1 and L2 from Example 1 were used.
Elements 14-16 of the Invention
[0064] The ink-transporting layer was prepared by coating dispersions formed from combining
urethane particles P 1 at 90 parts by weight with each of the binders B1-B3 at 10
parts by weight to give 20 % solids dispersions. The dispersions formed with binders
B1-B3 were coated with a 40 µm wire-wound rod on porous ink-retaining layer L-2.
Controls 19-21
[0065] The controls were prepared similar to Elements 14-16 except that the dispersions
formed by combining the particles with binders B1-B3 were coated on the porous ink-retaining
layer L1.
Printing
[0066] A test target comprised was printed with a Hewlett-Packard Photosmart ® printer.
The target consisted of 3 cm
2 color patches at 100 % density in each of the primary and secondary colors and black.
Fusing and Testing
[0067] The printed elements and controls were fused as in Example 2. The densities of the
printed patches were then read with the following results.
Table 4
Element |
Blue |
Cyan |
Magenta |
Yellow |
Green |
Red |
Black |
14 |
2.08 |
2.05 |
1.86 |
1.79 |
1.21 |
0.72 |
2.0 |
15 |
2.1 |
1.75 |
1.9 |
1.77 |
1.23 |
0.72 |
2.06 |
16 |
2.00 |
1.98 |
1.83 |
1.72 |
1.22 |
0.71 |
1.99 |
Control 19 |
1.85 |
2.07 |
1.68 |
1.65 |
1.22 |
0.73 |
1.88 |
Control 20 |
1.84 |
2.04 |
1.69 |
1.65 |
1.19 |
0.72 |
1.88 |
Control 21 |
1.84 |
1.96 |
1.68 |
1.64 |
1.19 |
0.72 |
1.88 |
[0068] The above results show that Elements 14-16 of the invention with two porous ink-retaining
layers and whose thin upper layer contains a mordant having significantly higher magenta,
yellow, blue and black densities than the control elements.