CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation in part of U.S. Application Serial Number
09/069,717 entitled "Reactive Ink Set For Ink-Jet Printing," by Askeland et al., filed
April 29, 1998; and is also a continuation in part of U.S. Application Serial Number
09/069,616 entitled "Multi-Chamber Ink Supply," by Askeland et al., filed April 29,
1998; all assigned to same assignee as the present invention.
FIELD OF INVENTION
[0002] This invention relates to ink-jet printers and the like and, more particularly, to
a compact and high print speed ink-jet printing system having enhanced performance.
BACKGROUND OF THE INVENTION
[0003] Ink-jet printing is a non-impact printing process in which droplets of ink are deposited
on a print medium in a particular order to form alphanumeric characters, area-fills,
and other patterns thereon. Low cost and high quality of the hardcopy output, combined
with relatively noise-free operation, have made ink-jet printers a popular alternative
to other types of printers used with computers.
[0004] The non-impact printing process of ink-jet printing involves the ejection of fine
droplets of ink onto a print medium such as paper, transparency film, or textiles
in response to electrical signals generated by a microprocessor. There are two basic
means currently available for achieving ink droplet ejection in ink-jet printing:
thermally and piezoelectrically. In piezoelectric ink-jet printing, the ink droplets
are ejected due to the vibrations of piezoelectric crystals, again, in response to
electrical signals generated by the microprocessor.
[0005] In thermal ink-jet printing, an ink-jet image is formed when a precise pattern of
dots is ejected from a drop generating device known as a "printhead" onto a printing
medium. The typical ink-jet printhead has an array of precisely formed nozzles (or
ejector portions) attached to a thermal ink-jet printhead substrate, such as silicon,
nickel, or polyimide, or a combination thereof. The substrate incorporates an array
of firing chambers or drop ejector portions that receive liquid ink (colorants dissolved
or dispersed in a solvent) through fluid communication with one or more ink reservoir.
Each firing chamber has a thin-film resistor, known as a "firing resistor," located
opposite the nozzle so ink can collect between the firing resistor and the nozzle.
The printhead is mounted on a carriage that travels along the width of the printer
(otherwise referred to as the "scan axis").
[0006] Commercially-available thermal ink-jet printers, such as DeskJet® printers available
from Hewlett-Packard Company, use inks of differing hues, namely, magenta, yellow,
and cyan, and optionally black. The particular set of colorants, e.g., dyes, used
to make the inks is called a "primary dye set." A spectrum of colors, e.g., secondary
colors, can be generated using different combinations of the primary dye set.
[0007] One category of ink-jet printers utilizes disposable printheads in which the ink
reservoirs are on-board the carriage, thus the term on-board or on-axis. The reservoirs
can be formed integrally with the printhead portions or they can be detachably connected
thereto.
[0008] Another category of ink-jet printers employs ink reservoirs that are not located
on the carriage, thus the term off-board or off-axis. In one case, the reservoir intermittently
replenishes the printhead with ink when the printhead travels to a stationary reservoir
periodically for replenishment. Another type makes use of a replaceable ink reservoir
connected to the printhead by a fluid conduit. The printhead is replenished with ink
through this fluid conduit.
[0009] The reservoirs may be individually (separate from other reservoirs) replaceable or
the reservoirs can be formed as one integral reservoir portion, to be replaced as
a unit.
[0010] Different printhead / ink reservoir configurations address different customer needs.
For example, on-board designs provide for ease of use. Printers using the off-board
designs provide for fewer interruptions during printing jobs which require larger
ink volumes, such as large format printing.
[0011] In general, a successful ink set for color ink-jet printing should have the following
properties: good crusting resistance, good stability, the proper viscosity, the proper
surface tension, good color-to-color bleed alleviation, vibrant colors, sharp edges,
rapid dry time, no negative reaction with the vehicle, consumer-safety, good permanence
(e.g., smearfastness, lightfastness, waterfastness), and low strike-through. When
placed into a thermal ink-jet system, the ink set should also be kogation-resistant.
[0012] Regardless of whether an ink is dye-based or pigment-based, ink-jet inks commonly
face the challenge of color-to-color or black-to-color bleed control. The term "bleed,"
as used herein, is defined to be the invasion of one color into another, once the
ink is deposited on the print medium, as evidenced by a ragged border therebetween.
Bleed occurs as colors mix both on the surface of the paper substrate as well as within
the substrate itself. The occurrence of bleed is especially problematic between a
black ink and an adjacently-printed color ink because it is all the more visible.
Hence, to achieve good print quality, bleed should be substantially reduced or eliminated
such that borders between colors are clean and free from the invasion of one color
into the other. Several approaches have been utilized in controlling bleed between
the printed images, many of which utilize reactive ink mechanisms.
[0013] One approach used for controlling bleed between the printed images, as disclosed
in U.S. patent No. 5,428,383, entitled "Method and Apparatus for Preventing Color
Bleed in a Multi-Ink Printing System," filed by Shields et al., and assigned to the
same assignee as the present invention, and incorporated herein by reference, is to
employ a precipitating agent (e.g., a multi-valent metal salt) in one ink, and a colorant,
preferably in the form of an organic dye having at least one and preferably two or
more carboxyl and/or carboxylate groups, in another ink, preferably the black ink.
When the inks are printed on the printing medium adjacent one another, the ink containing
the precipitating agent brings about the precipitation of the colorant with the carboxyl/carboxylate
group, thereby preventing the migration of the colorant in the other ink, thereby
reducing bleed between the two adjacently printed areas.
[0014] Another method of reducing bleed between ink-jet inks involves the use of pH-sensitive
dyes as disclosed in U.S. Patent No. 5,181,045 entitled "Bleed Alleviation Using pH-sensitive
Dyes/Inks," filed by Shields et al, and assigned to the same assignee as the present
invention, and incorporated herein by reference. It disclosed therein that an ink
having a pH-sensitive dye, the "pH-sensitive ink," would be prevented from bleeding
into an adjacent ink having an appropriate pH, the "target ink." More particularly,
migration of the ink having the pH-sensitive dye is prevented by rendering the dye
insoluble on the page by contact with the adjacent ink having the appropriate pH.
Thus, bleed is reduced or eliminated by using both the "pH-sensitive" ink as well
as the "target" ink. Typically, since the invasion of a black dye into a color ink
is more problematic than vice versa because of its greater visibility, the black ink
would employ the pH-sensitive dye and the pH of the color ink would be controlled
in the practice of the invention, such that the black ink would be prevented from
bleeding into the color ink. The method of U.S. Patent No. 5,181,045 requires a pH
differential of about 4 (or even 5) units to completely control bleed.
[0015] U.S. Patent No. 5,785,743 entitled "Bleed Alleviation in Ink-Jet Inks using Organic
Acids," filed by Adamic et al. on December 6, 1995, and assigned to the same assignee
as the present invention) and U.S. Patent 5,679,143 (entitled "Bleed Alleviation in
Ink-jet Inks Using Acids Containing a Basic Functional Group," filed by Looman and
assigned to the same assignee as the present invention), both incorporated herein
by reference, further disclose methods for controlling bleed by forcing the precipitation
of a pH-sensitive dye in one ink (the pH-sensitive ink) on the print medium by contacting
the pH-sensitive dye with a second ink (the target ink) having an appropriate pH (either
higher or lower than the first ink). Upon contact on the print medium, the pH-sensitive
dye of the first ink becomes insoluble, thus bleeding less. U.S. Application 08/567974
discloses the use of organic acids to reduce the pH differential required to effect
precipitation of a pH-sensitive dye colorant as compared to that disclosed in U.S.
Patent No. 5,181,045, described above. U.S. Patent 5,679,143 employs the use of an
organic acid having no basic functional groups and a pH adjusting organic compound
containing both acidic and basic functional groups, specifically, at least one acidic
functional group and at least one basic functional group, where the number of basic
functional groups is the same as or greater than the number of acidic functional groups.
The presence of the organic acid in the ink-jet ink composition reduces the pH differential
required to render insoluble the pH-sensitive colorant of a second encroaching ink-jet
ink composition, as described in U.S. Application No. 08/567974 above. The presence
of the dual-function pH adjusting compound further increases the concentration of
an acid functional group in the ink-jet ink composition while also increasing the
pH of the ink-jet ink composition to acceptable levels. Therefore, the dual-function
pH adjusting compound augments the bleed alleviation achieved by an organic acid alone
according to the mechanism disclosed in Serial No. 08/567974.
[0016] In order to prevent the occurrence of bleed between the primary (e.g., cyan, magenta,
and yellow) and secondary colors (e.g., red, blue, and green) with black, all the
three primary colors are designed to be reactive with the black ink according to reaction
mechanisms such as those described above (multi-valent metal salt, pH-sensitive dye).
[0017] The above solutions utilizing reactive inks, although of merit, do not maximize flexibility
in the design of the inks and printing system in which they are used. For example,
using reactive ink systems may lead to unwanted mixing of the reactive inks, hence
contributing to reliability problems in the printing system, particularly in compact
printhead arrangements or compact ink delivery arrangements.
[0018] U.S. Patent Application Serial Number 09/069717 entitled "Reactive Ink Set For Ink-Jet
Printing," filed April 29, 1998, by Askeland et al., discloses an ink set and method
for printing using the same, wherein the ink set comprises inks comprising an aqueous
vehicle and a colorant, the ink set comprising at least two mutually reactive inks;
and an ink non-reactive with the at least two mutually reactive inks. The ink set
utilizes the advantages of reactive inks while allowing flexibility in the design
of the inks and the architecture of the ink-jet printing systems in which they are
used.
[0019] U.S. Patent Application Serial Number 09/069616 entitled "Multi-Chamber Ink Supply,"
filed April 29, 1998, by Askeland et al., discloses, an ink-jet printing system and
ink supply configuration that can utilize the advantages of reactive inks while allowing
for maximum flexibility in the design and architecture of the ink-jet printing system.
The ink-jet printing apparatus comprises a printhead portion having at least three
ejector portions; a reservoir portion comprising at least three ink chambers, each
ink chamber for providing ink to one of the at least three ejector portions, two of
the ink chambers each chamber including one of a first or a second mutually reactive
inks and the other ink chamber including an ink non-reactive with the first and second
mutually reactive inks.
[0020] U.S. Patent Applications Serial Numbers 09/069717 and 09/069616 address either or
both the undesirable mixing of colors (e.g., bleed) and other image quality attributes.
When the ink set includes an ink non-reactive with the first ink, a printing method
(the under-printing method) may be employed to reduce bleed between the first ink
and the non-reactive ink or to enhance other print system attributes. In applying
the "under-printing" method, an area (herein referred to as the first area) to be
printed with the first ink (e.g., black) is also, at least partially, printed with
at least one ink reactive (e.g., magenta or yellow) with the first ink, thereby minimizing
the mixing of colors between the first area and a second area to be printed with the
non-reactive ink. These ink sets comprising a non-reactive ink subset, although of
great merit, do not address obtaining all of the image quality attribute enhancements
desirable in an ink-jet image.
[0021] Therefore, a need exists for an ink-jet printing system and ink supply configuration
that can utilize the advantages of reactive inks while allowing for maximum flexibility
in the design and architecture of the ink-jet printing system.
DISCLOSURE OF THE INVENTION
[0022] In accordance with the invention, an ink-jet printing system and fluid supply configuration
are disclosed that utilize the advantages of reactive fluids while allowing for maximum
flexibility in the design and architecture of the ink-jet printing system. The ink-jet
printing apparatus comprises a printhead portion having at least one integral printhead
portion, the printhead portion having at least two ejector portions; and at least
one reservoir portion associated with the printhead portion, the reservoir portion
having at least two reservoir chambers, each reservoir chamber for providing fluid
to one of the at least two ejector portions, one of the chambers including a reactant
fluid and the other chamber including at least one ink non-reactive with the reactant
fluid.
[0023] Additionally, in accordance with the invention, a fluid delivery apparatus for providing
fluid to an ink-jet printing system is disclosed, the fluid delivery apparatus comprises
a reservoir portion having at least one integral reservoir portion, the reservoir
portion having at least two reservoir chambers, each reservoir chamber for providing
fluid to the ink-jet printing system, one of the reservoir chambers including a reactant
fluid, the other reservoir chambers including an ink non-reactive with the reactant
fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 is an unscaled schematic representation of an ink-jet printing system depicting
an ink-jet printhead, fluid reservoir, and the control electronics.
[0025] Figure 2 is an unscaled schematic, partially sectioned, representation of an integral
ink-jet printhead.
[0026] Figure 3(a) is an unscaled schematic, partially sectioned, representation of an ink-jet
printhead with multiple integral printheads.
[0027] Figure 3 (b) is an unscaled schematic, partially sectioned, representation of another
ink-jet printhead with multiple integral printheads.
[0028] Figure 3 (c) is an unscaled schematic, partially sectioned, representation of another
ink-jet printhead with multiple integral printheads.
[0029] Figure 3 (d) is an unscaled schematic, partially sectioned, representation of another
ink-jet printhead with multiple integral printheads.
[0030] Figure 3 (e) is an unscaled schematic, partially sectioned, representation of another
ink-jet printhead with multiple integral printheads.
[0031] Figure 4 is an unscaled schematic representation of an on-board fluid delivery system
where the fluid reservoir is separately replaceable from the printhead.
[0032] Figure 5 is an unscaled schematic representation of an off-board fluid delivery system
where the fluid reservoir is connected to the printhead via a fluid conduit.
DETAILED DESCRIPTION OF THE INVENTION
DEFINITIONS
[0033] Fluid - Includes either or both the reactant fluid and ink compositions.
[0034] Reaction - when the solubility or state of one or more colorants in at least one
of two fluids reactive with one another, is changed as to immobilize the movement
of the at least one colorant on the print medium in the event that the fluids come
in contact with one another.
[0035] Reactant fluid - A fluid that is substantially devoid of color (i.e., the reactant
fluid may contain no colorant (e.g., dye or pigment) at all, or it may contain a colorant
that does not absorb in the visible light but may absorb in either or both IR or UV).
The reactant fluid comprises a component (a molecule or complex, or a functional group
in a molecule or complex) that is reactive with a component (a molecule or complex,
or a functional group in a molecule or complex) in an ink thus providing for enhanced
image integrity of printed areas created with the ink, such as, increased permanence
(e.g. waterfastness, smearfastness) or bleed alleviation; improved color vibrancy,
improved edge acuity, or reduced dry time; in the event that the reactant fluid and
the ink are printed at least partially on a same pre-determined area on a print medium,
or on pre-determined areas adjacent one another on a print medium.
[0036] Reactive fluid - a fluid that is reactive with another fluid.
[0037] Mutually reactive fluids - Fluids reactive with one another.
[0038] Integral Printhead - A printhead having an array of drop ejector portions that are
permanently attached to a rigid structure. Ejector portions are fabricated from materials
including silicon, nickel, polyimide, or a combination thereof. Such techniques of
forming a monolithic printhead are known in the art and are discussed in publication
such as U.S. Patent Numbers 4,438,191 and 4,922,265, both assigned to the assignee
of the present invention.
[0039] Printhead Portion - A printhead comprising one or more integral printhead portions.
[0040] Integral Reservoir Portion - A reservoir portion comprising a plurality of reservoir
chambers wherein the plurality of reservoir chambers are permanently affixed with
respect to each other.
[0041] Integral Print Cartridge - An ink jet printhead portion; and at least one reservoir
chamber, or an integral reservoir portion; forming an integral print cartridge.
[0042] On-board (on-axis) - A category of ink-jet printers utilizing disposable printheads
in which the fluid reservoirs are on-board the carriage. The reservoirs can be formed
integrally with the printhead portions or detachably connected thereto.
[0043] Off-board (off-axis) - A category of ink-jet printers employing fluid reservoirs
that are not located on the carriage. In one case, the reservoir intermittently replenishes
the printhead with fluid when the printhead travels to a stationary reservoir periodically
for replenishment. Another type makes use of a replaceable ink reservoir connected
to the printhead by a fluid conduit. The printhead is replenished with fluid through
this fluid conduit.
[0044] Scan axis - Axis defined by motion of a carriage associated with the printing system.
DESCRIPTION
[0045] Referring now to Figure 1, set forth therein is an unscaled schematic representation
of an ink-jet printing system 100 which includes a multi color ink delivery system
105 of the present invention employing at least two fluids, the fluids including a
reactant fluid and an ink non-reactive with the reactant fluid. The fluids may furthermore
include at least one ink reactive with the reactant fluid for enhancing any one of
a number of print system attributes such as bleed alleviation, smearfastness, reduced
dry time. Printing system 100 includes a printhead portion 110 that receives signals
from printing system control electronics 130 via electronic link 140 for selectively
depositing droplets of fluid available from an fluid reservoir portion 120 on a printing
medium 90 in response.
[0046] The printhead 110 comprises a plurality of ejector portions 115 for ejecting different
fluids. In an exemplary embodiment, the ejector portion 115 comprises ejector portions
115K, 1115C, 115M, 115Y, and 115F for ejecting black, cyan, magenta, and yellow inks,
and reactant fluid, respectively. However, more or less inks and reactant fluids can
be utilized, having same or different formulations depending on the printing application
and degree of print quality, color gamut, and other print attributes desired.
[0047] Each ejector portion receives fluid from a separate reservoir chamber (although in
some embodiments it is possible to have more than one reservoir chamber including
for supplying the same fluid to an ejector portion). In an exemplary embodiment, the
reservoir portion 120 includes reservoir chambers120K, 120C, 120M, and 120Y for housing
black, cyan, magenta, and yellow inks, and 120F for housing reactant fluid "F", respectively.
The reservoir chambers can be formed integrally with the printhead portion 110; or
can be detachably connected to the printhead portion, either as in the case of an
off-board or an on-board system. For example, there may be an optional separation
portion 160 between the reservoir portion and the printhead portion. Each reservoir
chamber may be individually replaceable. In a preferred embodiment, to simplify the
fluid delivery system, the reservoir chambers are formed as one integral reservoir
portion 120, to be replaced as a unit (i.e., integral reservoir portion).
[0048] In a preferred embodiment, the plurality of ejector portions 115, are arranged along
an axis to simplify and maximize space efficiency. This axis will be referred to as
the array axis "A." To further maximize space efficiency, the array axis "A" is parallel
to a scan axis "S" referring to the direction of travel for the printhead portion
over the printing medium during a printing operation.
[0049] In the remainder of the disclosure, by way of example, unless stated otherwise, "image
integrity" will be used to describe the desired effect obtained as the result of the
reaction between reactive fluids, for example between an ink reactive with the reactant
fluid or between two inks reactive with one another; and, black, cyan, magenta, and
yellow will be used to refer to the first through fourth inks. Furthermore, the term
"image integrity" will encompass print attributes such as bleed alleviation, reduced
dry time, smearfastness, and waterfastness that may be affected as the result of the
reaction between two reactive fluids. Additionally, when referring to an ink reactive
with the reactant fluid, the ink may be reactive or non-reactive, with another ink.
[0050] By way of example, Figure 1, represents an ink-jet printing system employing five
different reservoir chambers 120K, 120C, 120M, and 120Y, for housing four different
inks, first through fourth inks; and 120F for housing reactant fluid F, respectively,
in which the reactant fluid is reactive with at least one of ink. In one embodiment,
the reactant fluid and the at least one ink reactive with the reactant fluid are utilized
in an integral printhead portion. In another embodiment, the fluid set further comprises
an ink non-reactive with the reactant. In the embodiment employing an integral printhead,
the fluid set, preferably, includes an ink non-reactive with the reactant fluid. In
a preferred embodiment, the reactant fluid and the at least one ink reactive with
the reactant fluid are utilized in an integral printhead portion. In a preferred embodiment
the reactant fluid is reactive with at least one of the black, cyan, and magenta inks,
more preferably with black, cyan, and magenta inks, and non-reactive with the yellow
ink. In one embodiment, in addition to the reactant fluid being reactive with at least
one ink and non-reactive with at least one ink, at least two of the inks are reactive
with one another (otherwise referred to as "mutually reactive inks"), for example,
the black ink is reactive with at least the magenta ink or the yellow ink, and preferably,
with both the magenta and the yellow inks; and more preferably, the cyan ink is non-reactive
with the black ink. It should be appreciated by those skilled in the art, that the
present invention is not limited to a fixed number of inks and reactant fluids and
that more or less fluids, the fluids having same or different compositions, may be
used in the fluid set.
[0051] In one embodiment the inks are non-reactive with one another but are reactive with
the reactant fluid with the exception of the ink that is associated with the drop
ejector portion positioned adjacent the drop ejector portion associated with the reactant
fluid, the exceptional ink being non-reactive also with the reactant fluid.
[0052] It is not uncommon for fluids (including inks and reactant fluids) to puddle on the
nozzle plate of the ink-jet printhead. This puddling, in turn, may lead to the mixing
of the fluids, for example during the wiping process. This mixing of the fluids, especially
when reactive fluids are used in association with an integral printhead may result
in reliability problems in the firing chambers. Therefore, when using reactive fluid
approaches (regardless of whether the reaction is between two inks or between an ink
and the reactant fluid), such as those described above (or any other reactive approach
for that matter), it is preferable to separate the ejector portions associated with
the fluids that are reactive with one another (i.e., mutually reactive fluids). Thus,
it is preferred that the mutually reactive fluids are separated by at least one ejector
portion associated with a fluid non-reactive with the mutually reactive fluids to
provide a separation buffer between the mutually reactive fluids. In other words,
in an integral printhead configuration, no two mutually reactive fluids are associated
with ejector portions that are adjacent one another. This preference for separation
of adjacent ejector portions associated with mutually reactive inks, is existent in
all embodiments to be described in the remainder of the description of the present
invention. In a preferred embodiment, the reactant fluid is non-reactive with at least
one ink associated with the ejector portion which is adjacent the ejector portion
associated with the reactant fluid. In one embodiment, the reactant fluid and the
at least one ink non-reactive with the reactant fluid are contained in an integral
reservoir portion. In another embodiment, the reactant fluid and the at least one
ink non-reactive with the reactant fluid are utilized in an integral printhead portion.
In one preferred embodiment, the reactant fluid is non-reactive with the fourth ink;
the first ink is mutually reactive with the third ink, and preferably, with both the
third and fourth inks; and the first ink is non-reactive with the second ink. In one
preferred embodiment the first, second, third, and fourth, inks are black, cyan, magenta,
and yellow, respectively.
[0053] The reaction between mutually reactive fluids may employ any one of mechanisms well-known
in the art such as the use of a pH-sensitive colorant, or the use of a precipitating
agent, as described in the aforementioned patents and applications. The present invention
can be employed in any reactive system, regardless of the purpose for the reaction,
where the reactant fluid is reactive with at least one ink, and in addition, also
when at least two of the inks are reactive with one another such as when the first
ink is designed to be reactive with the third, and optionally, the fourth inks. The
one or more reactions can serve to enhance any one of a number of desired image integrity
attributes. Furthermore, the reaction scheme, between any two fluids reactive with
one another (e.g., fluids one and two) may be the same or different than reaction
schemes between any other two reactive fluids (e.g., fluids three and four or, fluids
one and four) including reactions between inks and between reactant fluid and an ink;
and each reaction scheme may comprise one or more reaction mechanisms (e.g., multi-valent
metal salts, cross-linking reaction).
[0054] Fluid sets employing the present invention will enhance image integrity (e.g., bleed)
between adjacently printed areas where one of the adjacent areas is printed, at least
partially, with at least one first reactive fluid and the other area is printed with
at least another second reactive fluid reactive with the first fluid; or in an alternate
embodiment, one of the adjacent areas printed (or to be printed) with an ink reactive
with the reactant fluid is also printed, at least partially, with the reactant fluid,
and the other print area is printed with another ink that may or may not be reactive
with either of the two fluids printed on the one adjacent print area. The present
fluid sets, may also enhance other image integrity attributes such as smearfastness
and waterfastness where an area to be printed with an ink reactive with the reactant
fluid is also printed, at least partially, with the reactant fluid, either before,
after, or substantially simultaneously with, the reactive ink. In an alternate embodiment
the fluid set comprises at least two mutually reactive inks. In another embodiment
employing at least two mutually reactive inks, an ink non-reactive (for example the
second ink) with the mutually reactive inks, can be employed such that the non-reactive
ink is associated with the ejector portion located between the ejector portions associated
with the two mutually reactive inks.
[0055] When an area adjacent to another print area is to be printed with an ink non-reactive
with any other fluid, it is preferred that the non-reactive ink (e.g., fourth ink)
has a color, preferably yellow, that will exhibit the least objectionable diffusion
into its adjacently printed areas.
[0056] In descriptions stated above such as inks, reactive, non-reactive fluid arrangements;
the reservoir, printhead, and print cartridge arrangements; will also be applicable
to the figures below.
[0057] Referring now to Figure 2, an integral printhead portion 500 comprising a plurality
of ejector portions 550; 550K, 550C, 550M, and 550Y; for ejecting a plurality of inks,
and 550F for ejecting a reactant fluid, is shown, broken away, with only the ejector
portions illustrated. In a preferred embodiment, the plurality of inks include black,
cyan, magenta, and yellow inks. Each ejector portion in printhead portion 500 includes
at least one row of nozzles or orifi for ejecting a fluid associated with the ejector
portion, and preferably arranged along a paper axis "P," perpendicular to the scan
axis "S." The reactant fluid is reactive with at least one of the inks, and preferably
non-reactive with the ink associated with the ejector portion adjacent the ejector
portion associated with the reactant fluid. In an alternate embodiment at least two
of the inks, for example, first and third inks, are mutually reactive. In a preferred
embodiment, the first ink is black.
[0058] Referring now to Figure 3(a), printhead portion 600 has been divided into two integral
printheads 600I and 600II. In a preferred embodiment, printhead 600I comprises ejector
portions 600K and 600C, and printhead 600II comprises ejector portions 600M, 600Y,
and 600F. Each of the ejector portions, such as 600K, may comprise one or more corresponding
ejector portions (e.g., for example, there may be two ejector portions associated
with a fluid, such as black ink, the association being with one or more reservoir
chambers). In one embodiment, ejector portions 600K and 600C are associated with black
and cyan inks, and ejector portions 600M, 600Y, and 600F are associate with magenta
and yellow inks and reactant fluid, respectively, wherein the magenta and the yellow
inks are reactive with the black ink, and the cyan ink is non-reactive with the black
ink, and preferably, the yellow ink is non-reactive with both the reactant fluid and
the magenta ink.
[0059] Referring now to Figure 3(b), printhead portion 610 has been divided into two integral
printheads 610I and 610II. In a preferred embodiment, printhead 610I comprises ejector
portions 610K, 610C, and 610M; and printhead 610II comprises ejector portions 610Y,
and 610F. In one embodiment, ejector portions 610K, 610C, and 610M are associated
with black, cyan, and magenta inks; and ejector portions 610Y, and 610F are associate
with yellow ink and reactant fluid, respectively, wherein the magenta and the yellow
inks are reactive with the black ink and the cyan ink is non-reactive with the black
and magenta inks.
[0060] Referring now to Figure 3(c), printhead portion 620 has been divided into two integral
printheads 620I and 620II. In a preferred embodiment, printhead 620I comprises ejector
portions 620K
1, 620K
2, and 620C; and printhead 620II comprises ejector portions 620M, 620Y, and 620F. As
can be noted, more than one ejector portion, e.g., 620K
1 and 620 K
2, are associated with a single fluid, e.g., black ink. In one embodiment, ejector
portions 620K
1, 620 K
2, are associated with black ink, and 620C is associated with, cyan ink; and ejector
portions 620M, 620Y, and 620F are associated with magenta and yellow inks and reactant
fluid, respectively, wherein the magenta and the yellow inks are reactive with the
black ink and the cyan ink is non-reactive with the black ink.
[0061] Referring now to Figure 3(d), printhead portion 630 has been divided into two integral
printheads 630I and 630II. In a preferred embodiment, printhead 630I comprises ejector
portions 630K, 630C, 630M, and 630Y; and printhead 630II comprises ejector portion
630F. In one embodiment, ejector portions 630K, 630C, 630M, and 630Y are associated
with black, cyan, magenta, and yellow inks; and ejector portion 630F is associated
with reactant fluid, respectively, wherein the magenta and the yellow inks are reactive
with the black ink and the cyan ink is non-reactive with the black ink. In another
embodiment the inks are non-reactive with one another but are reactive with the reactant
fluid.
[0062] Referring now to Figure 3(e), printhead portion 640 has been divided into three integral
printheads 640I, 640II, and 640III. In a preferred embodiment, printhead 640I comprises
ejector portions 640F
1, 640Y
1, and 640C
1; printhead 640II comprises ejector portions 640M
1, 640K, and 640M
2; and printhead 640III comprises ejector portions 640C
2, 640Y
2, and 640F
2. In one embodiment, ejector portions 640K, 640C
1 and 640C
2, 640M
1 and 640M
2, and 640Y
1 and 640Y
2 are associated with black, cyan, magenta, and yellow inks; and ejector portions 640F
1 and 640F
2 are associated with reactant fluid; respectively. In one embodiment, the cyan and
the yellow inks are reactive with the black ink and the magenta ink is non-reactive
with the black ink.
[0063] Referring now to Figure 4, one embodiment of ink delivery system 105' is shown in
schematic form. Ink delivery system 105' includes a printhead portion 110' comprising
a plurality of ejector portions 115' for ejecting different fluids, and a reservoir
portion 120' for supplying fluids to the printhead portion 110' by way of fluid outlets
150' and fluid inlets 130'. When each fluid outlet 150' is connected to each fluid
inlet 130', it forms a fluidic connection that fluidically couples a reservoir chamber
having a particular fluid with a corresponding ejector portion in a printhead portion
utilizing the same fluid.
[0064] In a preferred embodiments, fluid outlets 150' include 150'K, 150'C, 150'M, 150'Y,
and 150'F are configured to connect to fluid inlets 130'K, 130'C, 130'M, 130'Y, and
130'F respectiyely, hence providing black, cyan, magenta, and yellow inks, and reactant
fluid from their corresponding fluid reservoir chambers 120'K, 120'C, 120'M, 120'Y,
and reactant fluid reservoir chamber 120'F; to ejector portions 115'K, 115'C, 115'M,
115'Y, and 115'F respectively.
[0065] In a preferred embodiment, for compactness of design, fluid outlets 150, fluid inlets
130', reservoir chambers 120', and ejector portions 115' are arranged along an array
axis that is preferably parallel to the scan axis "S."
[0066] The reactant fluid is reactive with at least one ink, preferably with three inks.
In one embodiment, at least two of the inks are mutually reactive. In a preferred
embodiment, the first ink is black. Preferably, the first ink is mutually reactive
with the third ink, and preferably with both the third and fourth inks; and non-reactive
with the second ink; and the reactant fluid is non-reactive with the fourth ink. In
the preferred embodiment the first, second, third, and fourth, inks are black, cyan,
magenta, and yellow.
[0067] In a preferred embodiment, the reservoir chambers 120'K, 120'C, 120'M; and 120'Y
and their corresponding fluid outlets 150'K, 150'C, 150'M, 150'Y, and 150'F are positioned
along the scan axis "S," in a predetermined positioning order same as that for their
corresponding ejector portions 115'K, 115'C, 115'M, 115'Y, and 115'F; and their corresponding
fluid inlets 130'K, 130'C, 130'M, 130'Y, and 130'F; respectively. This similar positioning
order, as depicted in Figure 4, provides for maximum distance between the fluidic
connections connecting the fluids reactive with one another, hence minimizing unwanted
contamination between mutually reactive fluids, particularly in the event of possible
leakage in the fluid connections.
[0068] Figure 5 depicts a representation of one embodiment of printing system 100". Printing
system 100" includes printing medium input 230"A and output 230"B trays for storing
printing medium (not shown) both before and after, respectively, the printing medium
is fed through a print zone 232". A carriage 234" supports a printhead portion 110"
and scans over print zone 232" in a scan direction "S" to allow the ejectors portions
(not shown) associated with printhead portions 110" to selectively deposit one or
more fluids on the printing medium. The printhead portion 110" is fluidically connected
to a reservoir portion 120" via conduit 216". The reservoir portion 120" may be placed
in a location that scans with the carriage 234" or in a location that does not, to
allow for varying carriage configurations. In the embodiment depicted in Figure 5,
printhead portion 110" comprising five ejector portions 115"K, 115"C, 115"M, 115"Y,
and 115"F (not shown); is spaced from the reservoir portion 120" comprising five reservoir
chambers 120"K, 120"C, 120"M, 120"Y, and 120"F; to allow the reservoir portion 120"
to be placed in a location that does not scan with carriage 234". Printhead portion
110" receives ink and reactant fluid from reservoir portions 120" via conduit 216".
[0069] It should be appreciated by those skilled in the art that the number and color of
inks and reactant fluid in the fluid set is not limited to the examples above and
that more or less number of inks having the same or different colors may be employed.
It should further be appreciated that the designation of first through fourth inks
is not limited to black, cyan, magenta, and yellow and also that when a non-reactive
subset is used any one of the inks may define the non-reactive subset. By way of example,
the ink set could comprise: black, cyan
1, cyan
2, magenta
1, magent
2, and yellow, wherein the designations "1" and "2" refer to inks having the same hue
but a different colorant concentrations or the same ink formulation; or black, cyan,
magenta, yellow, red, green, blue, and white to provide a larger color gamut. Furthermore,
the reactant fluid reservoir and its corresponding ejector portion may be placed at
any one or more locations consistent with the present invention, for example on either
or both sides of the inks as for example illustrated by the configuration depicted
in Figure 3(e). Consistent with the present invention, preferably, any two fluids
associated with adjacently located ejector portions are non-reactive with one another.
FLUIDS
[0070] The present fluid set comprises at least one reactant fluid and at least one ink
reactive with the reactant fluid, and preferably, at least one ink non-reactive with
the reactant fluid. The fluids comprise an aqueous vehicle. The inks further comprise
at lease one colorant. The reactant fluid further comprises at least one component
for reacting with at least one component in the at least one ink with which the reactant
fluid is reactive. At least one ink, preferably all, and most preferably, all but
one, is reactive with the reactant fluid. In one embodiment, at least two of the inks
are also mutually reactive with one another (e.g., first and third inks). In another
embodiment, the ink set comprises at least one ink non-reactive (e.g., second ink)
with the at least two mutually reactive inks.
[0071] The reaction between the reactive fluids may employ any one of reactive mechanisms
well-known in the art such as the use of a pH-sensitive colorant, or the use of a
precipitating agent, as described in the aforementioned patents and applications.
The present invention can be employed in any reactive system when the reactant fluid
is reactive with at least one ink. As stated earlier, the reaction between the reactive
fluids can serve to enhance any one of a number of print system attributes such as
bleed alleviation, smearfastness, reduced dry time, or any other desirable attribute.
Furthermore, the reaction scheme, between any two reactive fluids (e.g., fluid one
and fluid two) may be the same or different than reaction schemes between any other
two reactive fluids (e.g., fluid three and fluid four or, fluid one and fluid four);
and each reaction scheme may comprise one or more reaction mechanisms, such as those
disclosed in U.S. Patent Application Serial Number 09/064,643, entitled "Ink Set For
Improved Print Quality," by Ma et. al., filed April 22, 1998, and assigned to the
same assignee as the present invention, and incorporated herein by reference in its
entirety.
AQUEOUS VEHICLE
[0072] The aqueous vehicle is water or a mixture of water and at least one water-soluble
organic solvent, as is well-known in the art. Selection of a suitable mixture depends
on requirements of the specific application, such as the desired surface tension and
viscosity, the selected colorant, drying time of the ink-jet fluid, and the type of
print medium onto which the fluid will be printed.
REACTIVE COMPONENTS
[0073] Depending on the reaction mechanism employed, the reactive fluids may have additional
components. For example, when the reaction mechanism for reducing bleed is by precipitation
of a pH-sensitive colorant in the first ink, either or both the reactant fluid and
the reactive third and fourth inks comprise an organic acid in sufficient amount to
render the pH-sensitive colorant of the first ink insoluble upon contact, as disclosed
in U.S. Patent 5,679,143 and U.S. Application 08/567974, mentioned above. Similarly,
when the reaction mechanism is based on the use of a precipitating agent, such as
multi-valent metal salts, as disclosed in the aforementioned patents, either or both
the reactant fluid and the third and fourth inks contain a precipitating agent, e.g.,
multi-valent metal salt.
[0074] Alternatively, when there are multiple reaction schemes, as for example, those disclosed
in Ma, all desired reactive components compatible with one another in a given fluid
composition may be present in the reactant fluid and any other reactive ink. For example,
Ma discloses, a set of printing liquids comprising: a first anionic printing liquid
comprising an aqueous vehicle, at least one first colorant, and at least one first
anionic polymer; a second anionic printing liquid comprising an aqueous vehicle, at
least one second colorant, at least one second anionic polymer, and an acid additive
having a pKa up to the pKa of the at least first polymer of the first printing liquid;
a third cationic printing liquid comprising an aqueous vehicle, at least one third
colorant, at least one third cationic polymer, and a pH in the range from about 2
to about 5; and a fourth anionic printing liquid comprising an aqueous vehicle, at
least one fourth anionic dye, and a precipitating agent. By way of example and without
limiting the scope of the present invention, Ma provides the following ink set and
reaction schemes:
Carbon black pigment is used as the colorant in the first ink. The carbon black pigment
in the first ink, black (K), is stabilized by a carboxylated polymeric dispersant
(anionic) and the ink has a pH of about 8.
The magenta pigment in the second ink, magenta (M), is stabilized by a sulfonated
or phosphonated polymeric dispersant (anionic). The magenta ink has a carboxylic acid
additive and a pH of about 3.
The yellow pigment in the third ink, yellow (Y), is stabilized by a cationic polymeric
dispersant, and the ink has a pH of about 3.
The cyan colorant in the fourth ink, cyan (C), is an anionic water-soluble dye. The
cyan ink further contains a precipitating agent, here a multivalent metal salt, and
optionally a carboxylic acid additive. The ink has a pH of about 3.
The reaction between the black and magenta inks is caused by the pH difference between
the two inks and the excess hydrogen ions from the magenta ink. The black ink and
the yellow ink react by virtue of the opposite charge between the dispersants for
the black and the yellow pigments. The black ink and the cyan ink react due to the
precipitation of the dispersed black pigment by the multi-valent metal ions (precipitating
agent). Additionally, when the fourth ink (e.g., cyan) contains the optional acid,
the pH difference between the cyan and the black ink further enhances the precipitation
of the colorant in the black ink.
The reaction between the magenta and the yellow inks is caused by the opposite charge
between the dispersants for the magenta and the yellow pigments. The magenta and the
cyan inks react by virtue of the multivalent metal precipitating the dispersed magenta
pigment.
And, finally, the yellow ink and the cyan ink react due to the opposite charge between
the dispersed yellow pigment and the cyan dye.
[0075] In the present invention, the reactant fluid may contain all of the aforementioned
reactive components compatible with one another so as to provide for the proper reaction
mechanisms between the reactant fluid and an ink reactive with the reactant fluid
or between two inks reactive with one another. It is also within the scope of the
present invention to have a fluid set wherein the reactant fluid may have to react
with more than one ink to achieve the desired (that is, the reactant fluid may provide
a component such that in the event that the reactant fluid and two inks come into
contact with one another on a print medium a desirable reaction occurs).
[0076] Furthermore, the reactant fluid may contain polymeric or cross-linkable components
for rendering the images more permanent. For example, the reactive fluids (e.g., the
reactant fluid and an ink reactive with the reactant fluid) may each contain a component
that will react with the component in the other reactive fluid such that upon reacting
it will render the printed image more permanent.
COLORANTS
[0077] The colorants may be dye-based or pigment-based. As used herein, the term "pigment"
refers to a colorant that is insoluble in the aqueous vehicle, and includes disperse
dyes as well has pigments that are either dispersed with the aid of a dispersant or
those that are self-dispersed.
[0078] The colorants employed in the inks may be either dye or pigment-based. The choice
of colorants is dependent upon the particular printing application. As in the case
of the colorant for the first ink, the choice of colorant further depends on the reaction
mechanism of choice, for example - use of pH sensitive colorant, or the use of a precipitating
agent (e.g., multi-valent metal salt), or any other suitable reaction mechanism.
[0079] Examples of suitable colorants used in the first ink include organic dyes having
at least one and preferably two or more carboxyl and/or carboxylate groups examples
of which are listed in U.S. Patent No. 4,963,189 (filed by Hindagolla and assigned
to the same assignee as the present invention, and incorporated herein by reference),
and carboxylated pigment dispersions having a water insoluble colorant (e.g., pigment)
dispersed with a dispersant preferably containing carboxylate solubilizing groups,
such as those disclosed in U.S. Patent No. 5,085,698, and U.S. Patent 5,555,008, both
incorporated herein by reference; or self-dispersed pigments provided under the Trade
name Cabojet™ by Cabot Company.
[0080] Colorants for use in the other inks, i.e., second, third, and fourth inks, are well-known
in the art, and for example, as described in the aforementioned patents and applications.
ADDITIONAL COMPONENTS
[0081] The fluids may further comprise additional components such as biocides, surfactants,
and the like, each of which are commonly employed additives in ink-jet printing.
PRINTING METHOD
[0082] Fluid sets employing the present invention will enhance image integrity (e.g., bleed)
between adjacently printed areas where one of the adjacent areas is printed, at least
partially, with at least one reactive fluid and the other adjacent area is printed,
at least partially, with at least another fluid reactive with the at least one reactive
fluid. The present fluid sets, may also enhance image integrity (e.g., smearfastness
and waterfastness) where an area to be printed with a reactive ink is also printed,
at least partially, with the reactant fluid, either before, after, or substantially
simultaneously with, the reactive ink.
[0083] The printing method comprises:
providing an ink-jet fluid set, the fluid set comprising at least three fluids, the
fluid set comprising at least two fluids reactive with one another wherein the at
least two reactive fluids comprises at least one reactant fluid and at least one ink
reactive with the reactant fluid, and at least one ink non-reactive with the reactant
fluid;
selecting a first predetermined area on a print medium;
printing at least one drop of one reactive fluid on the first predetermined print
area to create a first printed element;
printing at least one drop of the other reactive fluid on the print medium to create
a second printed element, such that the second printed element at least partially
overlaps with the first printed element, thereby causing a reaction between the at
least one drop of the one reactive fluid and the other reactive fluid on the print
medium, thereby enhancing a print attribute.
[0084] In another embodiment, separate from or complementary to the printing method described
above, the printing method comprises:
providing an ink-jet fluid set, the fluid set comprising at least three fluids, the
fluid set comprising at least two fluids reactive with one another wherein the at
least two reactive fluids comprises at least one reactant fluid and at least one ink
reactive with the reactant fluid, and at least one ink non-reactive with the reactant
fluid;
selecting a first predetermined area on a print medium;
selecting a second predetermined print area on the print medium adjacent the first
predetermined print area;
printing at least one drop of one reactive fluid on the first predetermined print
area to create a first printed element;
printing at least one drop of the other reactive fluid on the print medium to create
a second printed element, such that the second printed element at least partially
overlaps with the first printed element, thereby causing a reaction between the at
least one drop of the one reactive fluid and the other reactive fluid on the print
medium;
printing at least one drop of the non-reactive ink on the second predetermined print
area;
thereby minimizing the mixing of the at least one drop of the ink reactive with the
reactant fluid with the at least one drop of the ink non-reactive with the reactant
fluid on the print medium, thereby reducing bleed between the adjacently printed areas.
[0085] It should be appreciated by those skilled in the art, that the reaction between the
reactant fluid and the ink reactive with the reactant fluid may take place regardless
of the order in which droplets of the reactant fluid and the ink reactive with the
reactant fluid are deposited on the print medium. For example, the reactant fluid
may be deposited first, after or substantially simultaneously with the ink reactive
with the reactant fluid, such as the black ink, as it may be required to achieve the
desired reactive result. Similarly, the ink to be printed on the second print area
may be deposited first, followed by the deposition of the reactant fluid and the ink
reactive with the reactant fluid on the first print, respectively.
INDUSTRIAL APPLICABILITY
[0086] The present ink-jet printing apparatus and fluid delivery apparatus are expected
to find commercial use in ink-jet printing.
[0087] Thus, there has been disclosed an ink-jet printing apparatus and a fluid delivery
apparatus. It will be readily apparent to those skilled in the art that various changes
and modifications of an obvious nature may be made without departing from the spirit
of the invention, and all such changes and modifications are considered to fall within
the scope of the invention as defined by the appended claims.