Note: Descriptions are shown in the official language in which they were submitted.
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PATENT APPLICATION
INK JET PRINTING PROCESS
BACKGROUND OF THE INVENTION
The present invention is directed to an ink jet printing
process. More specifically, the present invention is directed to an ink jet
printing process wherein color forming liquids ("inks") are jetted onto a
substrate. One embodiment of the present invention is directed to a
process which comprises (a) incorporating into an ink jet printing
apparatus (1)- a developing composition comprising u liquid vehicle
and a color developer; (2) an oxidizing composition comprising a liquid
vehicle and an oxidizing agent; (3) a coloring composition comprising
a liquid vehicle and a dye coupler; and (4) a fixing composition
comprising a liquid vehicle and a fixative; (b) causing droplets of the
developing composition to be ejected in an imagewise pattern onto
the substrate; (c) causing droplets of the oxidizing composition to be
ejected in an imagewise pattern onto the substrate; (d) causing
droplets of the coloring composition to be ejected in an imagewise
pattern onto the substrate; and (e) causing droplets of the fixing
composition to be ejected in an imagewise pattern onto the suostrate;
wherein the process results in at least some portions of the substrate
bearing images comprising all four of the developing composition, the
oxidizing composition, the coloring composition, and the fixing
composition, said portions forming a printed image.
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Ink jet printing systems generally are of two types:
continuous stream and drop-on-demand. In continuous stream ink jet
systems, ink is emitted in a continuous stream under pressure through at
least one orifice or nozzle. The stream is perturbed, causing it to break
up into droplets at a fixed distance from the orifice. At the break-up
point, the droplets are charged in accordance with digital data signals
and passed through an electrostatic field which adjusts the trajectory
of each droplet in order to direct it to a gutter for recirculation or a
specific location on a recording medium. In drop-on-demand systems,
a droplet is expelled from an orifice directly to a position on a recording
medium in accordance with digital data signals. A droplet is not
formed or expelled unless it is to be placed on the recording medium.
Since drop-on-demand systems require no ink recovery,
charging, or deflection, the system is much simpler than the continuous
stream type. There are three types of drop-on-demand ink jet systems.
One type of drop-on-demand system has as its major components an
ink filled channel or passageway having a nozzle on one end and a
piezoelectric transducer near the other end to produce pressure pulses.
The relatively large size of the transducer prevents close spacing of the
nozzles, and physical limitations of the transducer result in low ink drop
velocity. Low drop velocity seriously diminishes tolerances for drop
velocity variation and directionality, thus impacting the system's ability
to produce high quality copies. Drop-on-demand systems which use
piezoelectric devices to expel the droplets also suffer the disadvantage
of a slow printing speed.
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Another type of drop-on-demand system is known as
acoustic ink printing. As is known, an acoustic beam exerts a
radiation pressure against objects upon which it impinges. Thus, when
an acoustic beam impinges on a free surface (i.e., liquid/air interface)
of a pool of liquid from beneath, the radiation pressure which it exerts
against the surface of the pool may reach a sufficiently high level to
release individual droplets of liquid from the pool, despite the
restraining force of surface tension. Focusing the beam on or near the
surface of the pool intensifies the radiation pressure it exerts for a
given amount of input power. These principles have been applied to
prior ink jet and acoustic printing proposals. For example, K. A. Krause,
"Focusing Ink Jet Head," IBM Technical Disclosure Bulletin, Vol. 16, No.
4, September 1973, pp. 1168-1170 describes an ink jet in which an
acoustic beam emanating from a concave surface and confined by
a conical aperture was used to propel ink droplets out through a small
ejection orifice. Acoustic ink printers typically comprise one or more
acoustic radiators for illuminating the free surface of a pool of liquid
ink with respective acoustic beams. Each of these beams usually is
brought to focus at or near the surface of the reservoir (i.e., the
liquid/air interface). Furthermore, printing conventionally is performed
by independently modulating the excitation of the acoustic radiators
in accordance with the input data samples for the image that is to be
printed. This modulation enables the radiation pressure which each of
the beams exerts against the free ink surface to make brief, controlled
excursions to a sufficiently high pressure level for overcoming the
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restraining force of surface tension. That, in turn, causes individual
droplets of ink to be ejected from the free ink surface on demand at an
adequate velocity to cause them to deposit in an image configuration
on a nearby recording medium. The acoustic beam may be intensity
modulated or focused/defocused to control the ejection timing, or an
external source may be used to extract droplets from the acoustically
excited liquid on the surface of the pool on demand. Regardless of the
timing mechanism employed, the size of the ejected droplets is
determined by the waist diameter of the focused acoustic beam.
Acoustic ink printing is attractive because it does not require the nozzles
or the small ejection orifices which have caused many of the reliability
and pixel placement accuracy problems that conventional drop on
demand and continuous stream ink jet printers have suffered. The size
of the ejection orifice is a critical design parameter of an ink jet
because it determines the size of the droplets of ink that the jet ejects.
As a result, the size of the ejection orifice cannot be increased, without
sacrificing resolution. Acoustic printing has increased intrinsic reliability
because there are no nozzles to clog. As will be appreciated, the
elimination of the clogged nozzle failure mode is especially relevant to
the reliability of large arrays of ink ejectors, such as page width arrays
comprising several thousand separate ejectors. Furthermore, small
ejection orifices are avoided, so acoustic printing can be performed
with a greater variety of inks than conventional ink jet printing, including
inks having higher viscosities and inks containing pigments and other
particulate components. It has been found that acoustic ink printers
embodying printheads comprising acoustically illuminated spherical
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focusing lenses can print precisely positioned pixels (i.e., picture
elements) at resolutions which are sufficient for high quality printing of
relatively complex images. It has also has been discovered that the
size of the individual pixels printed by such a printer can be varied over
a significant range during operation, thereby accommodating, for
example, the printing of variably shaded images. Furthermore, the
known droplet ejector technology can be adapted to a variety of
printhead configurations, including (1) single ejector embodiments for
raster scan printing, (2) matrix configured ejector arrays for matrix
printing, and (3) several different types of pagewidth ejector arrays,
ranging from single row, sparse arrays for hybrid forms of parallel/serial
printing to multiple row staggered arrays with individual ejectors for
each of the pixel positions or addresses within a pagewidth image field
(i.e., single ejector/pixel/line) for ordinary line printing. Inks suitable
for
acoustic ink jet printing typically are liquid at ambient temperatures
(i.e., about 25 C), but in other embodiments the ink is in a solid state at
ambient temperatures and provision is made for liquefying the ink by
heating or any other suitable method prior to introduction of the ink into
the printhead. Images of two or more colors can be generated by
several methods, including by processes wherein a single printhead
launches acoustic waves into pools of different colored inks. Further
information regarding acoustic ink jet printing apparatus and processes
is disclosed in, for example, U.S. Patent 4,308,547, U.S. Patent 4,697,195,
U.S. Patent 5,028,937, U.S. Patent 5,041,849, U.S. Patent 4,751,529, U.S.
Patent 4,751,530, U.S. Patent 4,751,534, U.S. Patent 4,801,953, and U.S.
Patent 4,797,693.
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The use of focused acoustic beams to eject droplets of controlled
diameter and velocity from a free-liquid surface is also described in J.
Appl. Phys., vol. 65, no. 9 (1 May 1989) and references therein.
Still another type of drop-on-demand system is known as
thermal ink jet, or bubble jet, and produces high velocity droplets and
allows very close spacing of nozzles. The major components of this
type of drop-on-demand system are an ink filled channel having a
nozzle on one end and a heat generating resistor near the nozzle.
Printing signals representing digital information originate an electric
current pulse in a resistive layer within each ink passageway near the
orifice or nozzle, causing the ink vehicle (usually water) in the
immediate vicinity to vaporize almost instantaneously and create a
bubble. The ink at the orifice is forced out as a propelled droplet as the
bubble expands. When the hydrodynamic motion of the ink stops, the
process is ready to start all over again. With the introduction of a
droplet ejection system based upon thermally generated bubbles,
commonly referred to as the "bubble jet" system, the drop-on-demand
ink jet printers provide simpler, lower cost devices than their continuous
stream counterparts, and yet have substantially the same high speed
printing capability.
The operating sequence of the bubble jet system begins
with a current pulse through the resistive layer in the ink filled channel,
the resistive layer being in close proximity to the orifice or nozzle for that
channel. Heat is transferred from the resistor to the ink. The ink
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becomes superheated far above its normal boiling point, and for water
based ink, finally reaches the critical temperature for bubble formation
or nucleation of around 280 C. Once nucleated, the bubble or water
vapor thermally isolates the ink from the heater and no further heat
can be applied to the ink. This bubble expands until all the heat stored
in the ink in excess of the normal boiling point diffuses away or is used
to convert liquid to vapor, which removes heat due to heat of
vaporization. The expansion of the bubble forces a droplet of ink out of
the nozzle, and once the excess heat is removed, the bubble collapses
on the resistor. At this point, the resistor is no longer being heated
because the cUrrent pulse has passed and, concurrently with the
bubble collapse, the droplet is propelled at a high rate of speed in a
direction towards a recording medium. The resistive layer encounters a
severe cavitational force by the collapse of the bubble, which tends to
erode if. Subsequently, the ink channel refills by capillary action. This
entire bubble formation and collapse sequence occurs in about 10
microseconds. The channel can be refired after 100 to 500
microseconds minimum dwell time to enable the channel to be refilled
and to enable the dynamic refilling factors to become somewhat
dampened. Thermal ink jet processes are well known and are
described in, for example, U.S. Patent 4,601,777, U.S. Patent 4,251,824,
U.S. Patent 4,410,899, U.S. Patent 4,412,224, and U.S. Patent 4,532,530.
U.S. Patent 3,870,435 (Watanabe et al.) discloses an almost
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colorless aqueous ink containing a color coupler which is used to
inscribe a record on a recording sheet having a coated layer
containing a fine white powder and a color developer which reacts
with the color coupler to form a visual record of vivid color of highly
durable nature.
U.S. Patent 3,850,649 (Buerkley et al.) discloses an ink
composition which is particularly suitable for lithographic (wet) offset
printing and comprises a quick set vehicle mixed with an iron-
complexing agent. The composition provides a storable latent (i.e.
invisible or concealed) image when printed on a properly selected low
iron-content paper. Treatment of.the printed latent image with an iron
salt develops the image and makes it clearly visible. Visible material
can be printed with the latent material on the same paper using a
conventional 2-color offset press.
U.S. Patent 5,443,629 (Saville et al.) discloses a latent image
ink particularly for use in printing forms such as games or coioring
books. An offset lithographic press is used for imprinting a substantially
invisible image on a sheet of standard paper. The latent ink used to
form the latent image is a mixture of potassium ferrocyanide or other
suitable color fixing iron complexing compounds, white ink, and
varnish. A developing solution such as ferric chloride or ammonium
sulfate is subsequently added to the paper to render the image visible.
Japanese Patent Publication JP 77049366 B discloses a
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recording system which comprises a pen which applies a colorless ink
containing a color developer such as potassium ferrocyanide and a
hygroscopic compound such as glycerol dissolved in water to a paper
coated with a white mineral powder and a colorless compound such
as iron alum which forms color on reacting with the color developer.
Japanese Patent Publication JP 9030107 A discloses a
process which includes ejection of droplets of multiple color ink
compositions to a recording medium having an absorbing layer for
coloring agents to make the coloring agent in the ink composition
adhere to the recording image to form a color image. Each of the
coloring agents in the color ink compositions are localized at a specific
depth of the absorbing layer for coloring agents, and the coloring
agents having different color tone do not mingle at the same depth in
the absorbing layer. Improved color reproduction can be achieved
when multiple types of coloring agent are printed on the same
position.
British Patent Publication GB 1398334 discloses a printing ink
composition capable of forming latent images which can be rendered
visible by reaction with metal salts which comprises (1) at least 40
percent by weight of a color stable, quick set vehicle free of inetallic
driers and having sufficient tack, viscosity, hydrophobicity, and
pigment carrying capacity for use in lithographic offset printing, and,
dispersed in the vehicle, (2) at least 10 percent of a light colored, solid,
particulate water insoluble reactant having an average particle size of
0.5 to 5.0 microns and being capable of forming a strongly colored
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complex with a coreactant iron salt. The composition is particularly
useful for the printing of educational aids such as self-answering
examination sheets.
German Patent Publication DE 2505077, discloses a water
borne writing or printing liquid for producing an invisible recording
which contains a mixture of gallic acid and alkali galiate which will
react with heavy metal salts.
"Leuco Dye System for Ink Jet Printing," W. T. Pimbley, IBM
Technical Disclosure Bulletin, Vol. 23, No. 4, p. 1387 (September 1980)
discloses ink jet printing with improved archival properties by using
leuco or vat dyes. The dyes convert to their permanent form when
oxidized. The record medium is first coated or impregnated with an
oxidizing agent such as acidic materials, such as acidified clays,
organic acids, or polymeric phenols. Upon combining with the oxidant,
the dyes convert to their permanent form, becoming insoluble and
having high tinctorial strength and excellent archival properties, such
as waferfastness and lightfastness.
While known compositions and processes are suitable for
their intended purposes, a need remains for improved ink jet printing
processes. In addition, a need remains for ink jet printing processes
which enable generation of photographic quality images on plain
paper. Further, a need remains for ink jet printing processes which
enable increased color gamut. Additionally, a need remains for ink jet
printing processes which enable increased color intensity. There is also
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a need for ink jet printing processes which generate permanent and
waterfast images. In addition, there is a need for ink jet printing
processes which exhibit desirable throughput speed. Further, there is a
need for ink jet printing processes which enable gray ievel printing
without specific regard to drop ejector resolution, wherein near
continuous tone or multigray level images can be realized with simple
300 dpi (dots per inch) drop ejectors. Additionally, there is a need for
ink jet printing processes which enable the printing of continuous tone
pictorial images without specific regard to drop ejector resolution. A
need also remains for ink jet printing processes which enable
production of variable spot sizes. In addition, a need remains for ink jet
printing processes which enable production of high resolution images.
SUMMARY OF THE INVENTION
It is an object of an aspect of the present invention to
provide ink jet printing processes with the above noted advantages.
It is another object of an aspect of the present invention to
provide improved ink jet printing processes.
It is yet another object of an aspect of the present
invention to provide ink jet printing processes which enable generation
of It is still another object of an aspect of the present invention to
provide ink jet printing processes which enable increased color gamut.
Another object of an aspect of the present invention is to
provide ink jet printing processes which enable increased color
intensity.
Yet another object of an aspect of the present invention is
to provide ink jet printing processes which generate permanent and
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waterfast images.
Stili another object of an aspect of the present invention is
to provide ink jet printing processes which exhibit desirable throughput
speed.
It is another object of an aspect of the present invention to
provide ink jet printing processes which enable gray level printing
without specific regard to drop ejector resolution, wherein near
continuous tone or multigray level images can be realized with simple
300 dpi (dots per inch) drop ejectors.
If is yet another object of an aspect of the present
invention to provide ink jet printing processes which enable the printing
of continuous tone pictorial images without specific regard to drop
ejector resolution.
It is still another object of an aspect of the present
invention to provide ink jet printing processes which enable production
of variable spot sizes.
Another object of an aspect of the present invention is to
provide ink jet printing processes which enable production of high
resolution images.
These and other objects of aspects of the present
invention (or specific embodiments thereof) can be achieved by
providing a process which comprises (a) incorporating into an ink jet
printing apparatus (1) a developing composition comprising a liquid
vehicle and a color developer; (2) an oxidizing composition comprising
a liquid vehicle and an oxidizing agent; (3) a coloring composition
comprising a liquid vehicle and a dye coupler; and (4) a fixing
composition comprising a liquid vehicle and a fixative; (b) causing
droplets of the developing composition to be ejected in an imagewise
pattern onto
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the substrate; (c) causing droplets of the oxidizing composition to be
ejected in an imagewise pattern onto the substrate; (d) causing
droplets of the coloring composition to be ejected in an imagewise
pattern onto the substrate; and (e) causing droplets of the fixing
composition to be ejected in an imagewise pattern onto the substrate;
wherein the process results in at least some portions of the substrate
bearing images comprising all four of the developing composition, the
oxidizing composition, the coloring composition, and the fixing
composition, said portions forming a printed image.
According to an aspect of the present invention, there is
provided a process which comprises:
a) incorporating into an ink jet printing apparatus:
a color forming composition comprising a liquid
vehicle and at least one color forming agent, and
a reacting composition comprising a liquid vehicle
and at least one mate(al capable of reacting with the color forming
agent to cause a desired color to form;
b) causing droplets of the color forming composition to be
ejected in an imagewise pattern onto a substrate; and
c) causing droplets of the reacting composition to be
ejected in an imagewise pattern onto the substrate; wherein the
process results in at least some portions of the substrate bearing images
comprising both the color forming composition and the reacting
composition, the portions forming a printed image, wherein one of i)
the color forming composition and ii) the reacting composition is
applied to the substrate in fixed volumes per pixel, and the other of i)
and ii) is applied to the substrate in varying volume per pixel, thereby
varying the intensity of color of the printed image.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view illustrating a multicolor, multi-
printhead, scanning type thermal ink jet printer useful for the present
invention;
Figure 2 is a view taken along line B-B of Figure 1, illustrating
the nozzle arrays of the multicolor, multi-printhead thermal ink jet
recording head assembly;
Figure 3 is an isometric view of a multicolor, single
printhead thermal ink jet printer having replaceable ink jet supply tanks
useful for the present invention;
Figure 4 is a partially exploded isometric view of a
multicolor, single printhead thermal ink jet cartridge used in the printer
of Figure 3 with integral printhead and ink connectors and replaceable
ink tanks;
Figure 5 is a schematic, partially shown side elevation view
of an acoustic ink jet printer useful for the present invention;
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Figure 6 is a schematic representation of an acoustic ink jet
printhead used in the. apparatus of Figure 5 and showing ink droplets
moving toward a recording medium on the transport belt;
Figure 7 is an unscaled, cross-sectional view of a first
embodiment acoustic droplet ejector which is shown ejecting a droplet
of a marking fluid;
Figure 8 is an unscaled cross-sectional view of a second
embodiment acoustic droplet ejector which is shown ejecting a droplet
of a marking fluid;
Figure 9 is an top-down schematic depiction of an array of
acoustic droplet ejectors in one ejector unit;
Figure 10 is a top-down schematic view of the organization
of a plurality of ejector units in a color printhead;
Figure 11 is a cross-sectional view of one embodiment of
the present invention, a material deposition head having multiple
ejection units;
Figure 12 is a perspective view of the structure of Figure 11;
Figure 13 is a schematic front elevation view of a portion of
on extended width or full width printhead which has been assembled
from a plurality of partial width array thermal ink jet or acoustic ink jet
printheads; and
Figure 14 illustrates schematically a process of the present
invention wherein gray scale images are generated by overlapping
droplets.
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DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to a process which
comprises (a) incorporating into an ink jet printing apparatus (1) a
developing composition comprising a liquid vehicle and a color
developer; (2) an oxidizing composition comprising a liquid vehicle and
an oxidizing agent; (3) a coloring composition comprising a liquid
vehicle and a dye coupler; and (4) a fixing composition comprising a
liquid vehicle and a fixative; (b) causing droplets of the developing
composition to be ejected in an imagewise pattern onto the substrate;
(c) causing droplets of the oxidizing composition to be ejected in an
imagewise pattern onto the substrate; (d) causing droplets of the
coloring composition to be ejected in an imagewise pattern onto the
substrate; and (e) causing droplets of the fixing composition to be
ejected in an imagewise pattern onto the substrate; wherein the
process results in at least some portions of the substrate bearing images
comprising all four of the developing composition, the oxidizing
composition, the coloring composition, and the fixing composition, said
portions forming a printed image. In one embodiment, only one
coloring composition is incorporated into the printing apparatus, and
the resulting images are of a single color. In another embodiment, at
least two different coloring compositions are incorporated into the
printing apparatus, and the resulting images are of at least two
different colors. In one specific embodiment, three different coloring
compositions are incorporated into the printing apparatus, one
containing a cyan dye coupler, one containing a magenta dye
coupler, and one containing a yellow dye coupler, thereby enabling
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the production of full color images. Specific embodiments of the
present invention are directed to the realization of continuous tone and
gray scale in images by (1) control of the time at which color forming
reactions are quenched by controlling the time peraod between
deposition of the color forming liquids and deposition of the fixing liquid;
(2) control of the extent of color forming reactions by limitation of the
quantity of one of the color forming liquids (i.e., the coloring
composition, the developing composition, or the oxidizing composition);
or (3) control of pixel size by drop placement control over the overlap
areas of drops of color forming liquids.
The present invention can employ any suitable or desired
ink jet printing apparatus, including continuous stream ink jet printers,
piezoelectric ink jet printers; thermal ink jet printers, acoustic ink jet
printers, hot melt ink jet printers of any of the above types, or the like.
Illustrated below are some examples of 'suitab(e apparatus for the
present invention; these examples are illustrative in nature and shouid
not be construed to limit the scope of the invention in any way..
Figure 1 shows a three-color printing mechanism 1
including a carriage 2 mounted for reciprocation in the directions of
arrow A-A on guide rails 3 and 4 secured to a frame (not shown) of the
printer. The carriage is driven along the guide rails by a suitable
mechanism such as a drive belt 5 supported between idler pulley 6 and
drive pulley 7, and driven by motor 8.
In the illustrated embodiment, to make a composite, multi-
color image, recording heads 9a, 9b, 9c, 9d, 9e, and 9f (delivering a
developing composition, an oxidizing composition, a coloring
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composition containing a yellow dye coupler, a coloring composition
containing a magenta dye coupler, a coloring composition containing
a cyan dye coupler, and a fixing composition, respectively) are
mounted in respective cartridge holders provided on the carriage 2. in
another embodiment (not shown), four recording heads are provided,
with one delivering a coloring composition, wherein the resulting
images are monochrome. Each cartridge holder includes appropriate
mechanical, electrical and fluid couplings so that selected ink drivers
can be activated in response to a suitable driving signal from a
controller 13 to expei ink from the cartridges onto a recording substrate
14 supported upon a platen 15.
Controller 13, which may be a microprocessor or
computer, receives signals representing a color composite image from
an image generator 16. Image generators are well known in the art.
Examples of a suitable image generator 16 are a scanner or digitizer
that scans data from a color original and generates signals in a
predetermined color space representing color readings, or a computer
and associated software and/or user interfaces that generate digital
image signals in a predetermined color space. There are many
accepted standards of color space format such as RGB, CYMK, CIELAB,
CIELUV and others. Signals from generator 16 are preferably stored at
least temporarily in a buffer memory 17. Memory 17 can be a. RAM or
ROM.
As shown in Figure 2, each cartridge 9 is provided with an
array of aligned nozzles 18. The nozzles can be of any size and spacing
depending on the desired resolution of the printing device. For
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example, if a resolution of 300 spots per inch is preferred, each nozzle
would be approximately 2 mil in diameter and would be spaced on
about 3.3 mil centers.
Printheads suitable for use in the apparatus illustrated in
Figures 1 and 2, including both "sideshooter" and "roofshooter"
configurations, are disclosed in, for example, U.S. Patent 4,638,337, U.S.
Patent 4,601,777, U.S. Patent 5,739,254, U.S. Patent 5,753,783, U.S. Patent
4,678,529, U.S. Patent 4,567,493, U.S. Patent 4,568,953, U.S. Patent
4,789,425, U.S. Patent 4,985,710, U.S. Patent 5,160,945, U.S. Patent
4,935,750, and U.S. Patent Re. 32,572.
Figure 3 illustrates an isometric view of a multicolor, sir, gle
printhead thermal ink jet printer 19 which is useful for the process of the
present invention. In the illustrated embodiment, the printer includes six
replaceable ink supply tanks 20 mounted in a removable ink jet
cartridge 21. The ink supply tanks supply a developing composition, an
oxidizing composition, a coloring composition containing a yellow dye
coupler, a coloring composition containing a magenta dye coupler, a
coloring composition containing a cyan dye coupler, and a fixing
composition. In another embodiment (not shown), four replaceable
ink supply tanks are provided, with one delivering a coloring
composition, wherein the resulting images are monochrome. The
removable cartridge is installed on a translatable carriage 22 which is
supported by carriage guide rails 23 fixedly mounted in frame 24 of the
printer. The removable cartridge is designed to consume or deplete
the ink from at least ten ink supply tanks of the same color of ink. The
carriage is
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translated back and forth along the guide rails by any suitable means
(not shown), as well known in the printer industry, under the control of
the printer controller (not shown). Referring also to Figure 4, the
multicolor, single printhead thermal ink jet cartridge 21 comprises a
housing 25 having an integral multicolor ink jet printhead 26 and ink
pipe connectors 27 which protrude from a wall 28 of the cartridge for
insertion into the ink tanks when the ink tanks are installed in the
cartridge housing. Ink flow paths, represented by dashed lines 29, in
the cartridge housing interconnects each of the ink connectors with
the separate inlets of the printhead. The ink jet cartridge, which
comprises the replaceable ink supply tanks that contain ink for
supplying ink to the printhead 26, includes an interfacing printed circuit
board (not shown) that is connected to the printer controller by ribbon
cable 30 through which electric signals are selectively applied to the
printhead to selectively eject ink droplets from the printhead nozzles
(not shown). The multicolor printhead 26 contains a plurality of ink
channels (not shown) which carry ink from each of the ink tanks to
respective groups of ink ejecting noales of the printhead.
When printing, the carriage 22 reciprocates back and forth
along the guide rails 23 in the direction of arrow 31. As the printhead 26
reciprocates back and forth across a recording medium 32, such as
single cut sheets of paper which are fed from an input stack 33 of
sheets, droplets of ink are expelled from selected ones of the printhead
nozzles towards the recording medium 32. The nozzles are typically
arranged in a linear array perpendicular to the reciprocating direction
of arrow 34. During each pass of the carriage 22, the recording
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medium 32 is held in a stationary position. At the end of each pass, the
recording medium is stepped in the direction of arrow 34.
A single sheet of recording medium 32 is fed from the input
stack 33 through the printer along a path defined by a curved platen
34a and a guide member 35. The sheet is driven along the path by a
transport roller 36 as is understood by those skilled in the art or, for
instance, as illustrated in U.S. Patent 5,534,902. As the recording
medium exits a slot between the platen 34 and guide member 35, the
sheet 32 is caused to reverse bow such that the sheet is supported by
the platen 34a at a flat portion thereof for printing by the printhead 26.
With continued reference to Figure 4, ink from each of the
ink supply tanks 20 is drawn by capillary action through the outlet port
37 in the ink supply tanks, the ink pipe connectors 38, and ink flow paths
29 in the cartridge housing to the printhead 26. The ink pipe
connectors and flow paths of the cartridge housing suppiies ink to the
printhead ink channels, replenishing the ink after each ink droplet
ejection from the nozzle associated with the printhead ink channel. It is
important that the ink at the nozzles be maintained at a slightly
negative pressure, so that the ink is prevented from dripping onto the
recording medium 32, and ensuring that ink droplets are placed on the
recording medium only when a droplet is ejected by an electrical
signal applied to the heating element in the ink channel for ~the
selected nozzle. A negative pressure also ensures that the size of the
ink droplets ejected from the nozzles remain substantially constant as
ink is depleted from the ink supply tanks. The negative pressure is
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CA 02472355 2004-07-20
usually in the range of -0.5 to -5.0 inches of water. One known method
of supplying ink at a negative pressure is to place within the ink supply
tanks an open cell foam or needled felt in which ink is absorbed and
suspended by capillary action. Ink tanks which contain ink holding
material are disclosed, for example, in U.S. Patent 5,185,614, U.S. Patent
4,771,295, and U.S. Patent 5,486,855.
In Figure 5, a partially shown side elevation view of an
acoustic ink jet printer 40 is depicted. The printer has a printer
controller 41, a transport belt 42 entrained on idler roller 43 and drive
roller 44 for movement in the direction of arrow 45, a plurality of
acoustic ink jet printheads 46 mounted on a carriage 47 which is
translatable along guide rails 48 in a direction orthogonal to the
direction of the printhead carriage, and a pair of input feed rollers 49
and 50 forming a nip therebetween for registering and feeding a
recording medium 51, such as a sheet of paper, on to the transport
belt. A pair of output feed rollers 52 and 53 drive the recording
medium from the transport belt, so that the recording medium is always
in the grip of either the feed rollers or the output rollers.
The printer controller 41 directly communicates with and
controls the input feed rollers 49 and 50, which accept the recording
medium from the input tray (not shown) after the recording medium
exits from a pair of guides 54 which direct the recording medium to the
input feed rollers. Printer controller 41 also directly communicates with
and controls the movement of the transport belt via a stepper motor
(not shown). In the illustrated embodiment, the acoustic ink jet
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printheads are translatable, partial width printheads, one printhead for
each of the liquids to be dispensed onto the recording medium, and
the transport belt is held stationary by the printer controller while the
printheads print a swath of an image. The transport belt is then
stepped a distance equal to the height of the printed swath or a
.portion thereof until the entire image is printed. Other embodiments
are possible, including an embodiment in which the printheads are
pagewidth and fixed and the transport belt is moved relative to the
printheads at a constant velocity. The printer controtler 41 directly
communicates with and controls the acoustic ink droplet ejectors 55
(see Figure 6) in each of the acoustic printheads.
Referring to Figure 6; a schematic representation of the
apparatus is shown in an enlarged cross-sectional view of a portion of
the printhead 46, the transport belt 42 with the recording medium 51
thereon, and the gap "G" between the face 56 of the printhead
having the apertures 57 therein and the transport belt. The printhead
46 ejects ink droplets 58 through the printhead apertures 57 directed
toward the recording medium 51 using acoustic ink dropiet ejectors 55.
Each acoustic ink droplet ejector includes a piezoelectric transducer of
RF source which creates a sound wave 59 in the ink 60 stored in the
printhead. A lens (not shown), such as a Fresnel lens, focuses the sound
wave at the ink surface 61 in the apertures 57. The acoustic pressure at
the ink surface 61 causes an ink droplet 58 to form. The fully formed
and ejected droplet 58 is directed and propelled towards the
recording medium 51.
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CA 02472355 2004-07-20
Refer now to Figure 7 for an illustration of an exemplary
acoustic droplet ejector 65. Figure 7 shows the droplet ejector 65
shortly after ejection of a droplet 66 of marking fluid 67 and before the
mound 68 on the free surface 69 of the marking fluid 67 has relaxed. As
droplets are ejected from such mounds, mound relaxation and
subsequent formation are prerequisites to the ejection of other dropiets.
The forming of the mound 68 and the ejection of the
droplet 66 are the results of pressure exerted by acoustic forces
created by a ZnO transducer 70. To generate the acoustic pressure, RF
drive energy is applied to the ZnO transducer 70 from an RF driver
source 71 via a bottom electrode 72 and a top electrode 73. The
acoustic energy from the transducer passes through a base 74 into an
acoustic lens 75. The acoustic lens focuses its received acoustic energy
into a small focal area which is at, or is near, the free surface 69 of the
marking fluid 67. Provided that the energy of the acoustic beam is
sufficient and properly focused relative to the free surface 69 of the
marking fluid, a mound 68 is formed and a droplet 66 is ejected.
Suitable acoustic lenses can be fabricated in many ways,
for example, by first depositing a suitable thickness of an etchable
matenal on the substrate. Then, the deposited materiai can be etched
to create the lenses. Alternatively, a master mold can be pressed into
the substrate at the location where the lenses are desired. By. heating
the substrate to its softening temperature acoustic lenses are created.
Still referring to Figure 7, the acoustic energy from the
acoustic lens 75 passes through a liquid cell 76 filled with a liquid (such
as water) having a relatively low attenuation. The bottom of the liquid
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CA 02472355 2004-07-20
cell 76 is formed by the base 74, the sides of the liquid cell are formed
by surfaces of an aperture in a top plate 77, and the top of the liquid
cell is sealed by an acoustically thin capping structure 78. By
"acousticalty thin" it is implied that the thickness of the capping
structure is less than the wavelength of the applied acoustic energy.
The droplet ejector 65 further includes a reservoir 79,
located over the capping structure 78, which holds marking fluid 67. As
shown in Figure 7, the reservoir includes an opening 80 defined by
sidewalls 81. It should be noted that the opening 80 is axially aligned
with the liquid cell 76. The side walls 81 include a plurality of portholes
82 through which the marking fluid passes. A pressure means 83 forces
marking fluid 67 through the portholes 82 so as to create a pool of
marking fluid having a free surface over the capping structure 78.
The droplet ejector 65 is dimensioned such that the free
surface 69 of the marking fluid is at, or is near, the acoustic focal area.
Since the capping structure 78 is acoustically thin, the acoustic energy
readily passes through the capping structure and into the overlaying
marking fluid.
A second embodiment acoustic droplet ejector 85 is
illustrated in Figure 8. The droplet ejector 85 does not have a liquid cell
76 sealed by an acoustically thin capping structure 78. Nor does it
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CA 02472355 2004-07-20
have the reservoir filled with marking fluid 67 nor any of the elements
associated with the reservoir. Rather, the acoustic energy passes from
the acoustic lens 75 directly into marking fluid 67. However, droplets 66
are still ejected from mounds 68 formed on the free surface 69 of the
marking fluid.
The individual acoustic droplet ejectors 65 and 85
(illustrated in Figures 7 and 8, respectively) are usually fabricated as part
of an array of acoustic droplet ejectors. Figure 9 shows a top-down
schematic depiction of an array 86 of individual droplet ejectors 87
which is particularly useful in printing applications. Since each droplet
ejector 87 is capable of ejecting a droplet with a smaller radius than
the droplet ejector itself, and since full coverage of the recording
medium is desired, the individual droplet ejectors are arrayed in offset
rows. In Figure 9, each droplet ejector in a given row is spaced a
distance 88 from its neighbors. That distance 88 is eight (8) times the
diameter of a droplet ejected from a droplet ejector. By offsetting
eight (8) rows of droplet ejectors at an angle 89, and by moving the
recording medium relative to the rows of droplet ejectors at a
predetermined rate, the array 100 can print fully filled in (no gaps
between pixels) lines or blocks.
Figure 9 illustrates an array of droplet ejectors capable of
single pass printing of one color of marking fluid, i.e., one ejection unit.
Multipie ejection units, each capable of ejecting a different material,
can be contained in a single material deposition head. Figure 10
schematically depicts a material deposition head 90 comprising six
arrays, designated arrays 91, 92, 93, 94, 95, and 96, each similar to the
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CA 02472355 2004-07-20
array 86 shown in Figure 9 (except that, for clarity, only three rows of
droplet ejectors 87 are shown). While in many applications the
distance between each of the arrays will be the same, such is not
required.
The benefit of a material deposition head such as material
deposition head 90 is readily apparent. By forming multiple arrays,
each capable of printing a different fluid, and by moving the recording
medium relative to the material deposition head at a controlled rate,
and by timing the ejection of each array correctly, registration of the
printed liquids can be readily achieved.
A cross-sectional, simplified (again, only three rows of the
eight rows of each ejection unit, and only two of the six ejection units)
depiction of the material deposition head 90, with the arrays 92 and 93,
is shown in Figure 11. The other arrays are not shown, but are
understood as being off to the left and right. As shown, the free surface
97 of the material 98 is contained within apertures 99 that are defined
in a thin plate 100 which is over a support 101. Figure 12, a perspective
view of Figure 11, better illustrates the apertures 99. It is to be
understood that each material 98 is confined in a chamber defined by
a channel 102 and the base. The individual droplet ejectors each align
with an associated aperture 99 which is axially aligned with that droplet
ejector's acoustic lens 75 (see also Figures 7 and 8). Droplets are
ejected from the free surface 97 through the apertures. The support
101 is directly bonded to a gloss base 28.
It is to be noted that Figures .11 and 12 and the subsequent
text and associated drawings all describe and illustrate individual
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CA 02472355 2004-07-20
droplet ejectors according to Figure 8. It should be noted that droplet
ejectors according to Figure 7 are also suitable for use in the apparatus
illustrated in Figures 11 and 12.
In Figure 13, a schematic front view of a portion of a
multifluid printhead 105 is shown in dashed line. The printhead 105
comprises a plurality of partial width array printheads 106 assembled in
at least two parallel rows. Each partial width array printhead has at
least four rows of nozzles 107 or, in the case of the nozzleless acoustic
ink jet printheads disclosed, for example, in U.S. Patent 4,697,195, the
partial width array printhead has at least four rows of droplet ejecting
locations 107. Each row of nozzles or droplet ejecting locations 107
eject a developing composition, an oxidizing composition, a coloring
composition containing a yellow dye coupler, a coloring composition
containing a magenta dye coupier, a coloring composition containing
a cyan dye coupler, or a fixing composition. In another embodiment
(not shown), four rows of nozzles are provided, with one delivering a
coloring composition, wherein the resulting images are monochrome.
In the illustrated embodiment, the partial width array printheads in
each of the two rows are equally spaced from each other and the
partial width array printheads in one row are offset from the partial
width array printheads in the other row, with the end portions 108 of
adjacent partial width array printheads in the two different rows
overlapping each other. Each partial width array printhead 106 has an
equal number of droplet ejecting locations or nozzles 107 per row and
an equal number of droplet ejecting locations or nozzles per printhead.
A sufficient number of staggered partial width array printheads 106 are
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CA 02472355 2004-07-20
assembled to provide for extended width printing or page width
printing, and when sufficient for page width printing, such a printhead
is referred to as a full width array printhead. An extended width array
printhead is one which has a plurality of partial width array printheads
but the rows of such printheads do not contain enough partial width
array printheads to print across the width of a page. An extended
width array printhead functions similarly to a partial width array
printhead, but is able to print a larger swath of information.
In all of the above printing apparatus illustrated in Figures 1
through 13, it will be appreciated that the number of liquids applied to
the substrate, and accordingly the number of ink supplies or- containers,
can be varied as desired. For example, for monochrome printing, the
printer will apply to the substrate four liquids, namely a developing
composition, an oxidizing composition, a fixing composition, and the
coloring composition of the desired color. In multicolor printing, black
may be applied in addition to cyan, magenta, and yellow, and the
printer will apply to the substrate seven liquids, namely a developing
composition, an oxidizing composition, a fixing composition, and the
cyan, magenta, yellow, and black coloring compositions.
Additional examples of suitable printing apparatus for the
present invention are disclosed in, for example, U.S. Patent 5,568,169,
U.S. Patent 5,565,113, U.S. Patent 5,596,355, U.S. Patent 5,371,531, U.S.
Patent 4,797,693, U.S. Patent 5,198,054, U.S. Patent 5,971,531 and U.S.
Patent 6,079,814.
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CA 02472355 2004-07-20
Any order of deposition of dye coupler, developer, and
oxidizing agent can be employed; typically, the seiected order is
dependent on the specific reagents employed and their formulations.
Fixative is always deposited last. In one embodiment of the present
invention, the timing of the deposition of the fixative determines the
color intensity. When developer, coupler, and oxidizer come together,
the reaction to form the dye starts. The intensity of the color depends
on the amount of dye formed. Deposition of the fixative at different
times along the reaction profile stops the dye forming reactions, and
the amount of dye formed at that moment in time determines the
color tone or intensity. Developer and coupler can usually be
deposited without regard to time. Once oxidizer and developer come
together, however, the timing of deposition of coupler and fixative
becomes more important, because the oxidized developer is highly
reactive and should be reacted with the coupler relatively soon after
its formation.
In one embodiment of the present invention, a multiplicity
of intensity or "gray" levels within a particular color can be obtained by
controlling the time between the point at which the developing
composition, oxidizing composition, and coloring composition all come
together and the point at which the fixing composition is deposited.
The reaction between the dye coupler and the oxidized developer
can be halted at a point short of maximum color intensity, thereby
creating one or more "gray" levels of color.
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CA 02472355 2004-07-20
In another embodiment of the present invention, a
muitiplicity of intensity or "gray" levels within a particular color can be
obtained by jetting fixed amounts of developing composition and
coloring composition onto the substrate in combination with varying
amounts of oxidizing composition, with the oxidizing agent in the
oxidizing composition being present in reaction limiting quantities with
respect to the color developer in the developing composition and the
dye coupler in the coloring composition. More specifically, the
printhead for jetting the oxidizing composition can have a multiplicity of
channels, each of which jet a different volume of oxidizing compound,
as required. Alternatively, the printhead for jetting the oxidizing
composition can jet drops of very small volume, and multiple small
drops of oxidizing composition can be deposited at a given pixel
location, depending on the intensity or "darkness" or saturation of color
desired at that pixel location. High resolution gray level printing can
thus be obtained without loss of throughput speed, which might
otherwise be associated with gray level ink jet printing processes.
Alternatively, instead of varying the amount or volume of oxidizing
composition, the amount or volume of developing composition and/or
the amount or volume of coioring composition can be varied by the
above methods to obtain gray level prints.
In yet another embodiment of the present invention, high
resolution and gray scaie images can be generated by generating
spots of varying sizes on the substrate. More specifically, the
developing composition, coloring composition(s), and oxidizing
composition are jetted in an imagewise pattern so that the overlap of
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CA 02472355 2004-07-20
droplets of these three compositions is controlled. Pixel size can
thereby be modulated to realize variable spot sizes, and high resolution
gray level printing can thus be obtained without loss of throughput
speed which might otherwise be associated with gray level ink jet
printing processes. As illustrated schematically in Figure 14, the
developer composition droplets 201, the oxidizing composition droplets
203, and the coloring composition droplets 205 can be jetted onto the
substrate 207 with varying amounts of overlap 209, thereby forming
image areas of varying size. In a full color printing process, three
coloring compositions are employed to form varying size image areas
of, for example, cyan, magenta, and yellow.
The developing composition generally comprises a liquid
vehicle and a color developer or developing agent, and functions as a
color forming component in the process of the present invention. For
the purpose of simplicity, the developing composition will at times
hereinafter be referred to as an ink. Any liquid can be employed as the
major component of the liquid vehicle, provided that it dissolves or
disperses the components of the composition and is of a viscosity
appropriate for the selected drop ejector. For example, in thermal ink
jet printing systems, a preferred liquid vehicle is water. In other drop
ejectors, such as those employing continuous stream processes,
piezoelectric ink jet printers, acoustic ink jet printers, and the like, other
liquids can also be employed, such as hydrocarbons, glycols, ethers,
sulfones such as sulfolane, pyrrolidinones such as 2-pyrrolidinone and N-
methyl pyrrolidinone, other dipolar aprotic solvents, and the like, as well
as mixtures thereof. The developing composition can also contain
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CA 02472355 2004-07-20
other components which might improve its performance as an ink jet
ink, such as humectants, penetrants, cosolvents, jetting aids, or the like,
set forth in more detail hereinbelow. The developing composition
typically contains the color developer in an amount of from about 0.05
to about 15 percent by weight of the developing composition,
preferably from about 0.1 to about 10 percent by weight of the
developing composition, and more preferably from about 0.5 to about
5 percent by weight of the developing composition, although the
amount can .be outside of these ranges.
Examples of color developers or developing agents
include phenylenediamines, of the formulae
NH2 NH2
HR
or
NHR
wherein R is a hydrogen atom, an alkyl group, preferably with from 1 to
about 4 carbon atoms, or a substituted alkyl group, wherein the
benzene ring can be substituted, and wherein 2 or more substituents
can be joined together to form additional rings, such as
p-phenylenediamine, of the formula
H2N 0 HZ
o-phenylenediamine, of the formula
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CA 02472355 2004-07-20
NH2
NH2
monomethyl-p-phenylenediamine, of the formula
- CH3
HZN
and the like. Parficularly preferred as color developers are. N,N-dialkyl-
p-phenylenediamines, of the general formula
H2N RiR2
wherein each of Ri and R2, independently of the other, is an alkyl
group, preferably with from 1 to about 4 carbon atoms, or a substituted
alkyl group, wherein the benzene ring can be substituted, and wherein
2 or more substituents can be joined together to form additional rings.
Specific examples of N,N-dialkyi-p-phenyienediamines include N,N-
dimethyl-p-phenylenediamine, of the formula
CH3
H2N ~ ~ --N
C H3
N,N-diethyl-p-phenylenediamine, of the formula
C2H5
HZN < / '
C2H5
N,N-diethyi-p-phenylenediamine hydrochloride, of the formula
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CA 02472355 2004-07-20
HSC2,, N-IC2H5
=HCI
NH2
N,N-diethyl-p=phenylenediamine hemisulfate, of the formula
HSC2,.,.C2H5
I \ =~/zHZS4a
NH2
N,N-diethyl-p-phenylenediamine sulfur dioxide complex, of the formula
H5C2,,NiC2H5
=S02='/zH20
NHz
N,N-diethyl-toluene-2,5-diamine hydrochloride, of the formula
H5C2,,N,,C2H5
=HCI
CH3
NH2
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CA 02472355 2004-07-20
2-(p-amino-N-ethylanilino)ethanol sulfate, of the formula
H5C2,,,.CH2CH2OH
.H2SO4
NH2
N-ethyl-N-(O-methanesulphonamidoethyl)-4-aminoaniline, of the
formula
_ C2H5
H2N
~ ~CH2CH2NHS02CH3
N-(2-(4-amino-N-ethyt-m-toluidino)ethyl)-methanesulfonamide
sesquisulfate hydrate, of the formula
H5C2,~N~CH2CH2NHSO2CH3
=1'/~H2SO4
=H20
CH3
NH2
2-((4-amino-m-tolyl)ethylamino)ethanol sulfate, of the formula
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CA 02472355 2004-07-20
H5C2.,,N~CH2CH2OH
( \ .H2SO4
CH3
NH2
, . .
4-(N-ethyl-N-2-methane sulfonyiaminoethyl)-2-methyiphenylene
diamine sesquisulfate, of the formula
H5C2,,,N,,CH2CH2N HSO2CH3
=1'/~H2SO4
.! CH3
NH2
and the like. The latter is particularly preferred because, as a function
of pH, it can exist in cationic and zwitterionic forms and both forms can
react with an ionized dye coupler, albeit at different rates. Also suitable
are hydroquinones, of the formula
HO <D OH
wherein the benzene ring can be substituted, and wherein 2 or more
substituents can be joined together to form additional rings, such as
hydroquinone, of the formula
HO OH
chlorohydroquinone, of the formula
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CA 02472355 2004-07-20
HO OH
CI
bromohydroquinone, of the formula
HO OH
Br
toluhydroquinone, of the formula
HO ~ ~ OH
CH3
methoxyhydroquinone, of the formula
HO OH
OCH3
and the like, catechol, of the formula
OH
OH
and its derivatives, such as pyrogallol, of the formula
~ OH
HO OH
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CA 02472355 2004-07-20
4-phenyl catechol, of the formula
OH
OH
gallic acid, of the formula
HO
HO ~ / COOH
H
methyl gailate, of the formula
HO
0
HO P \
OCH3
H
gallacetophenone, of the formula
HO
0
ii
HO CH3
HO
methyl ester of gentisic acid, of the formula
0
C--OCH3
HO d OH
-38-
CA 02472355 2004-07-20
daphnetin, of the formula
OH
HO O 0
5,8-methano-5,6,7,8-tetrahydro-1,4-dihydroxynaphthalene, of the
formula
OH
H
and the like. Also suitable are p-aminophenols, of the general formula
OH
NRIR2
wherein Ri and R2 each, independently of the other, are hydrogen
atoms, alkyl groups, preferably with from 1 to about 4 carbon atoms, or
substituted alkyl groups, wherein the benzene ring can be substituted,
and wherein 2 or more substituents can be joined together'to form
additional rings, such as p-aminophenol, of the formula
HO C) H2
o-aminophenol, of the formula
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CA 02472355 2004-07-20
NH2
OH
2-methyl-p-aminophenol, of the formula
H2N Z OH
CH3
2-hydroxymethyl-p-aminophenol, of the formula
H2N OH
CH2OH
1-amino-2-naphthol-6-sulfonic acid (Eikonogen), of the formula
NH2
OH
\ I /
HSO3
1-amino-2-naphthol-3,6-disulfonic acid (Diogen), of the formula
NH2
OH
\ I /
HSO3 SO3H
4=aminophenol hydrochloride, of the formula
-40-
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CA 02472355 2004-07-20
OH
=HCI
NH2
N-methyl-p-aminophenol (Metol), of the formula
CH
~ 3
HO
- ~-i
2,4-diaminophenol (Amidol), of the formula
H2N < OH
H2
,
2,4-diaminophenol dihydrochioride, of the formula
OH
H2
=2HCI
NH2
2,3,4-triaminophenol, of the formula
OH
H2N R2:,H,2
Triamol, of the formula
-41-
CA 02472355 2004-07-20
NH2
H2N ( OH
HZ
N-(4-hydroxyphenyl)glycine (Glycin), of the formula
HO O
~CHZCOOH
4-(hydroxyethylamino)-3-methyl-l-hydroxybenzene, of the formula
H
HO \CH2CH2OH
CH3
4-(di(hydroxyethyl)amino)-1-hydroxybenzene, of the formula
C CH2CH2OH
HO
"\CH2CH2OH
N-(2'-hydroxy-5'-aminobenzyl)-3-hydroxyaniline hydrochloride, of the
formula
OH H H
1 I
-N
H .HCI
NH2 H
4-amino-2-benzylaminophenol, of the formula
-42-
CA 02472355 2004-07-20
OH H H
N-C I0
H
~ \ .
NH2
2-amino-4-(p-hydroxybenzylamino)-phenol, of the formula
NH2
H H
HO
H
m-methyl-p-hydroxy-N-phenylmorpholine, of the formula
CH3
O N OH
~ ~
\...-/ ,
1-(4-hydroxyphenyl)-pyrrolidine, of the formula
CH3
DNOH
p-hydroxydiphenylamine (Duratol), of the formula
p-aminosalicylic acid (Neol), of the formula
-43-
CA 02472355 2004-07-20
OH
COOH
=HCI
NH2
2-methyl-4-aminophenol hydrochloride (Monomet), of the formula
OH
CH3
=HCI
NH2
N-(hydroxyethyl)-o-aminophenol (Atomal), of the formula
H"'Ne CH2CH2OH
OH
~
3-(hydroxymethyl)-4-hydroxyaniline hemisulfate (Edinol), of the formula
OH
CH2OH
I ='/~H2SO4
NH2
and the like; Diphenal, of the formula
-44-
CA 02472355 2004-07-20
H2N
NH2.HC1
HO
and the like. Mixtures of two or more developers can also be used.
Commercially available examples of suitable developers include CD-2
[diethylamino-o-toluidine hydrochioride, CAS# 2051-79-8], CD-3 [4-(N-
ethyl-N-2-methane sulfonylaminoethyl)-2-methylphenylene diamine
sesquisulfate, CAS# 25640-71-3], and CD-4 [2-[(4-amino-m-
tolyl)ethylamino]ethanol sulfate, CAS#25646-77-9], all available from
Eastman Kodak Co., Rochester, NY, and the like. Further information
regarding color developers is disclosed in, for example, SPSE Handbook
of Photographic Science and Engineering, W. Thomas, Jr., ed., John
Wiley & Sons (New York 1973); NebJette's Handbook of Photography
and Reprography, 7th ed., J. Sturge, ed., Van Nostrand Reinhold Co.
(New York 1977); Modern Photographic Processing, G. Haist, John Wiley
& Sons (New York 1979); U.S. Patent 477,486, U.S. Patent 1,799,568, U.S.
Patent 1,712,716, U.S. Patent 1,758,892, U.S. Patent 1,758,762, U.S. Patent
2,610,122, U.S. Patent 2,385,763, U.S. Patent 3,622,629, U.S. Patent
3,762,922, U.S. Patent 1,937,844, U.S. Patent 3,265,499, U.S. Patent
3,134,673, U.S. Patent 3,091,530, U.S. Patent 2,193,015, U.S. Patent
2,688,549, U.S. Patent 2,688,548, U.S. Patent 2,691,589, U.S. Patent
3,672,896, U.S. Patent 2,289,367, U.S. Patent 3,241,967, U.S. Patent
3,330,839, U.S. Patent 2,685,516, U.S. Patent 2,852,374, U.S. Patent
3,672,891, U.S. Patent 1,939,231, U.S. Patent 2,181,944, U.S. Patent
3,459,549, U.S. Patent 1,390,260, U.S. Patent 1,663,959, U.S. Patent
-45-
CA 02472355 2004-07-20
2,587,276, U.S. Patent 2,857,275, U.S. Patent 2,857,274, U.S. Patent
3,293,034, U.S. Patent 3,287,125, U.S. Patent 3,287,124, U.S. Patent
3,455,916, U.S. Patent 2,843,481, U.S. Patent 3,723,117, U.S. Patent
2,596,978, U.S. Patent 1,082,622, U.S. Patent 2,220,929, U.S. Patent
2,419,975, U.S. Patent 2,685,514, U.S. Patent 3,782,949, U.S. Patent
853,643, U.S. Patent 2,943,109, and U.S. Patent 2,397,676; British Patent
1,191,535, British Patent 295,939, British Patent 1,210,417, British Patent
1,273,081, British Patent 1,003,783, British Patent 928,671, British Patent
989,383, British Patent 430,264, British Patent 767,700, British Patent
783,727, British Patent 542,502, British Patent 650,911, British Patent
679,677, British Patent 728,368, British Patent 757,271, British Patent
997,033, British Patent 761,301, British Patent 954,106, British Patent
679,678, British Patent 757,840, British Patent 459,665, British Patent
479,466, British Patent 1,122,085, British Patent 1,327,033, British Patent
1,191,535, British Patent 1,327,034, British Patent 1,327,035, British Patent
1,154,385, British Patent 943,928, British Patent 466,625, and British Patent
466,626; French Patent 1,480,920, French Patent 1,380,163, and French
Patent 325,385; German Patent 945,606, German Patent 955,025,
German Patent 158,741, German Patent 875,048, German Patent
870,418, German Patent 945,606, German Patent 1,151,175, German
Patent 1,047,618, German Patent 1,079,455, German Patent 34,342,
German Patent 36,746, and German Patent 97,596; Canadian Patent
931,009.
In silver halide development processes, the developer
generally is oxidized by interaction with the silver halide in the film. For
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CA 02472355 2004-07-20
the instant invention, the developer is reacted with an oxidant or
oxidizing agent. The developer, upon oxidation, is converted to a form
capable of reacting with a dye coupler to form a dye. For example, a
developer of the N,N-dialkyl-p-phenylenediamine class, upon
oxidation, is converted to the quinone diimine, as follows:
NH2 NH
+ oxidant ----~- I ~
NRIR2 X'e ONRIR2
wherein X is an anion derived from the oxidant.
The oxidizing composition generally comprises a liquid
vehicle and an oxidizing agent, and functions as a color forming
component in the process of the present invention. For the purpose of
simplicity, the developing composition will at times hereinafter be
referred to as an ink. Any liquid can be employed as the major
component of the liquid vehicle, provided that it dissolves or disperses
the components of the composition and is of a viscosity appropriate for
the selected drop ejector. For example, in thermal ink jet printing
systems, a preferred liquid vehicle is water. In other drop ejectors, such
as those employing continuous stream processes, piezoelectric ink jet
printers, acoustic ink jet printers, and the like, other liquids can also be
employed, such as hydrocarbons, glycols, ethers, sulfones such as
sulfolane, pyrrolidinones such as 2-pyrrolidinone and N-methyl
pyrrolid'inone, other dipolar aprotic solvents, and the like, as well as
mixtures thereof. The oxidizing composition can also contain other
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CA 02472355 2004-07-20
components which might improve its performance as an ink jet ink,
such as humectants, penetrants, cosolvents, jetting aids, or the like, set
forth in more detail hereinbelow. The oxidizing composition typicaliy
contains the oxidizing agent in an amount of from about 0.05 to about
15 percent by weight of the oxidizing composition, preferably from
about 0.1 to about 10 percent by weight of the oxidizing composition,
and more preferably from about 0.5 to about 5 percent by weight of
the oxidizing composition, although the amount can be outside of
these ranges. The reaction between the oxidizing agent and the color
developer is stoichiometric, and to obtain full color intensity, a full
stoichiometric amount or an excess amount of oxidizing agent is
employed to oxidize all of the developer. In one embodiment of the
present invention, color tone or intensity is controlled by the deposition
of variable stoichiometricaily insufficient amounts of oxidizing agent.
Examples of suitable oxidizing agents include potassium
peroxydisulfate, ammonium peroxydisulfate, hydrogen peroxide,
alkylhydroperoxides, of the general formula
RI
R2--C-O-O-H
k3
wherein Ri, R2, and R3 each, independently of the others, are alkyl
groups, preferably with 1 or 2 carbon atoms, although the number of
carbon atoms can be outside of this range, or alkylaryl groups,
preferably with from 7 to about 9 carbon atoms, although the number
of carbon atoms can be outside of this range, such as t-butyl
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CA 02472355 2004-07-20
hydroperoxide, cumene hydroperoxide, and the like, dialkylperoxides,
of the generai formula
Ri R6
R2-~-O-O-C-RS
k3 ~4
wherein Ri, R2, R3, R4, R5, and Re each, independently of the others, are
alkyl groups, preferably with 1 or 2 carbon atoms, although the number
of carbon atoms can be outside of this range, or alkylaryl groups,
preferably with from 7 to about 9 carbon atoms, although the number
of carbon atoms can be outside of this range, such as di-t-
buty(peroxide, dicumylperoxide, and the like, wherein the class of
dialkyl peroxides also includes substituted dialkyl peroxides, such as t-
butylperoxybenzoate, of the formula
CH3 O
H3C-~-O--O-C
&3
t-butylperoxy isopropyl carbonate, of the formula
H3C-cH O-O-C-O-CH CH3
i
&3 H
and the like, diacylperoxides, of the general formula
0 0
R r-8-0-0-C--R2
wherein R, and R2 are each, independently of the others, alkyl groups,
preferably with 1 or 2 carbon atoms, aryl groups, preferably with from 6
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CA 02472355 2004-07-20
to about 9 carbon atoms, or alkylaryl groups, preferably with from 7 to
about 9 carbon atoms, such as benzoyl peroxide, pivaloyl peroxide,
and the like, peroxycarbonates, such as sodium percarbonate and the
like, and the like, as well as mixtures thereof. Peroxides such as the
above are available from, for example, Aldrich Chemical Co.,
Milwaukee; WI, and Alfa Aesar, division of Johnson Matthey Catalog
Co., Inc.; Ward Hill, MA.
As indicated, the developer in its oxidized form can react
with a dye coupler to form a dye. The coloring composition generally
comprises a liquid vehicle and a dye coupler, and functions as a color
forming component in the process of the present invention. For the
purpose of simplicity, the developing composition wiil at times
hereinafter be referred to as an ink. Any liquid can be employed as the
major component of the liquid vehicle, provided that it dissolves or
disperses the components of the composition and is of a viscosity
appropriate for the selected drop ejector. For example, in thermal ink
jet printing systems, a preferred liquid vehicle is water. In other drop
ejectors, such as those employing continuous stream processes,
piezoelectric ink jet printers, acoustic ink jet printers, and the like, other
liquids can also be employed, such as hydrocarbons, glycols, ethers,
sulfones such as sulfolane, pyrrolidinones such as 2-pyrroiidinone and N-
methyl pyrrolidinone, other dipolar aprotic solvents, and the like, as weli.
as mixtures thereof. The coloring composition can also contain other
components which might improve its performance as an ink jet ink.
such as humectants, penetrants, cosolvents, jetting aids, or the like, set
forth in more detail hereinbelow. The coloring composition typically
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CA 02472355 2004-07-20
contains the dye coupler in an amount of from about 0.05 to about 15
percent by weight of the coioring composition, preferably from about
0.1 to about 10 percent by weight of the coloring composition, and
more preferably from about 0.5 to about 5 percent by weight of the
coloring composition, although the amount can be outside of these
ranges. The reaction between the dye coupler and the color
developer is stoichiometric, and to obtain full color intensity, a full
stoichiometric amount or an excess amount of oxidizing agent is
employed to oxidize all of the developer. In one embodiment of the
present invention, color tone or intensity is controlled by the deposition
of variable stoichiometrically insufficient amounts of dye coupler.
Examples of suitable cyan dye couplers include substituted
phenois and a-naphthols, including those of the general formulae
OH H
I
N R
X
OH H
CI
R'
X
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CA 02472355 2004-07-20
OH O
/ \ ~A r
H
x
OH O
OAr
H
\ ,.- .
x
...
OH
/ \ \ ( /
R X
and the like, wherein X is a hydrogen atom, a chiorine atom, an alkoxy
group (-OR), an aryloxy group (-OAr), or a thioaryl group (-SAr), n is an
integer representing the number of repeat -CHr units, and preferably is
from about 1 to about 3, R and R' each, independently of the others,
are organic segments which provide desired solubility characteristics,
such as alkyl groups, preferably with from 1 to about 22 carbon atoms,
or polar solubilizing groups, such as -COOH or -S03H, and Ar is an aryl
group, including substituted aryl groups, preferably with from 6 to about
14 carbon atoms, or an aryiaikyi group, including substituted aryiaikyi
groups, preferably with from 7 to about 36 carbon atoms. Amphiphilic
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CA 02472355 2004-07-20
cyan couplers, such as 1-N-stearoyl-3-N-(1'-hydroxy-2'-naphthoyl)-
phenylenediamine-4-sulphonic acid, believed to be of the formula
H3CN%WC18H37
OH O
N
H 03H
X
or a salt thereof, such as a sodium salt, are particularly preferred for
water based ink formulations such as those suitable for thermal ink jet
printing.
Examples of suitable yellow dye couplers include a-
ketocarboxamides and pivaloylacetanilides, of the general formulae
O
Z / Y
-4 O
IQ,
ballast
and
H3C 0
H3C-~ O
H3G /
F( baNast
wherein X is a hydrogen atom, a chlorine atom, a-OSOzR group, a
-SO2R group, a-O-C(=O)R group, or a -SAr group, wherein R is an alkyl
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CA 02472355 2004-07-20
group, preferably with from 1 to about 22 carbon atoms, and Ar is an
aryl group, preferably with from 6 to about 22 carbon atoms, Y, Z, and
"ballast" are each, independently of the others, solubilizing groups, such
as an alkyl group (-R), a carboxyl group, a sulfonyl group, or an
alkylamide group (-NH-COR), wherein R is an alkyl group, preferably
with from 1 to about 22 carbon atoms. Substituents Y. and Z can be
used to attach ballasting or solubilizing groups and to alter the
reactivity of the coupler and the hue of the resulting dyes. Coupling to
the oxidized developer . generally occurs with displacement of
substituent X. Specific examples of suitable yellow dye couplers include
4-(p-toluenesulfonylamino)-w-benzoylacetanilide, of the formula
O H O _
H3
/
H H
a-benzoyl-o-methoxyacetanilide, of the formula
H3CO
0_0 H O H H
dichloroacetanilide, of the formula
Ci
O H O
H H
CI
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CA 02472355 2004-07-20
and the like. Amphiphilic yellow couplers, such as para-stearoylamino-
benzoyl-acetanilide-3',5'-dicarboxylic acid, believed to be of the
formula
COOH
0=~ H H
C17H35 COOH
or meta-stearoyiamino-benzoyl-acetanilide-para'-carboxylic acid,
believed to be of the formula
H35C17\C O
H-tf
O H O
COOH
H H
or salts thereof, such as the sodium salts, are parficularly preferred for
water based ink formulations such as those suitable for thermal ink jet
printing.
Examples of suitable magenta dye couplers include those
derived from the 1-aryl-2-pyrazolin-5-ones, of the general formulae
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CA 02472355 2004-07-20
. / \
N-N
N"" R'
H X
and
N-N
O N
H X
wherein X is
-O
O H
-O-C-N-R
0
-O-C-R
H O
-N-S-R
-R
-S
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CA 02472355 2004-07-20
-S-A r
or
-N==N-A r
R, R', and R" each, independently of the others, are organic segments
which provide desired solubility characteristics, such as alkyl groups,
preferably with from 1 to about 22 carbon atoms, or polar solubilizing
groups, such as -COOH or -SO3H, and Ar is an aryl group, including
substituted aryl groups, preferably with from 6 to about 14 carbon
atoms, or an arylalkyl group, including substituted arylalkyl g.roups,
preferably with from 7 to about 36 carbon atoms, the pyrazolo-(3,2,-c)-
5-triazoles and related isomers, of the general formula
~(CH2)"
N N---;{ ba Ilast
H3C N -N~I
I
X H
wherein X is a chlorine atom, a thloalkyl group (-SR), a thioaryl group
(-SAr), or an aryloxy group (-OAr), n is an integer representing the
number of repeat -CHr units, and preferably is from 0 to about 3, R is an
alkyl group, preferably with from 1 to about 22 carbon atoms, Ar is an
aryl group, preferably with from 6 to about 22 carbon atoms, and
"ballast" represents a solubilizing group, such as an alkyl group (-R), a
carboxyl group, a sulfonyl group, or an alkylamide group (-NH-COR),
wherein R is an alkyl group, preferably with from 1 to about 22 carbon
atoms, and the like. Also suitable are cyanoacetjrl derivatives of cyclic
systems, such as cyanoacetylcoumarone, of the formula
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CA 02472355 2004-07-20
H
C-~-C=-=v
H =
indazolones, of the general formula
O
N-H
wherein A is a hydrogen atom or a substituent selected to optimize
characteristics such as solubility, reactivity, hue, stability, or the like.
For
example, substituents such as sulfonate (-SO3) or carboxylate (-COOH)
can enhance water solubility and suitability for use in aqueous liquids.
Specific examples of suitable magenta dye couplers include 2-
cyanoacetyl coumarone, of the formula
H O O HC
aF ~
1-(2,4,6-trichlorophenyl)-3-p-nitroanilino-2-pyrazoline-5-one, of the
formula
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CA 02472355 2004-07-20
H
O2N \' N-C CH2
~ 'N ~,
~N~ 'O
CI CI
and the like. Amphiphilic magenta couplers, such as 3-heptadecyl-l-
(4'-suifophenyl)-2-pyrazoline-5-one, believed to be of the formula
H
H35C17-C ~-'X
03H
wherein X is a hydrogen atom or a chlorine atom, or 1-(5'-sulpho-3'-
stearoyl-aminophenyl)-2-pyrazoline-5-one, believed to be of the
formula
O ~N
OI~
H 35 C 1 C~N \ SO3H
7 I
H
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CA 02472355 2004-07-20
or salts thereof, such as the sodium salts, are particularly preferred for
water based ink formulations such as those suitable for use in thermal
ink jet printing. Further information regarding dye couplers is disclosed
in, for example, SPSE Handbook of Photographic Science and
Engineering, W. Thomas, Jr., ed., John Wiley & Sons (New York 1973);
Neblette's Handbook of Photography and Reprography, 7th ed., J.
Sturge, ed., Van Nostrand Reinhold Co. (New York 1977); and 'The
Chemistry of Color Photography," W. C. Guida et al., Journal of
Chemical Education, Vol. 52, No. 10, p. 622 (October 1975).
At least one of the developing composition, coloring
composition, and oxidizing composition is of a pH sufficiently alkaline to
drive the coupling reaction between the oxidized developer and the
dye coupler. Accordingly, at least one of these compositions typically
also includes a base and/or a buffer. While it is generally simplest to
include the base and/or buffer in the oxidizing composition, the
developing composition and/or the coloring composition can also
have its. pH adjusted to an appropriate level to enable the coupling
reaction. The composition(s) containing a base and/or a buffer, and
having its pH adjusted to enable the coupling reaction, will hereinafter
be referred to as the pH adjusted composition. The pH of the pH
adjusted composition generally is over about 9, and preferably is from
about 10 to about 13, although the value can be outside of this range.
Examples of compositions which can be added to the pH adjusted
composition to obtain the desired pH include hydroxides such as
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sodium hydroxide, tetramethylammonium hydroxide, and the like,
potassium carbonate, sodium phosphate, or the like, as well as mixtures
thereof.
The fixing composition generally comprises a liquid vehicle
and a fixative. For the purpose of simplicity, the fixing composition will
at times hereinafter be referred to as an ink. Any liquid can be
employed as the major component of the liquid vehicle, provided that
it dissolves or disperses the components of the composition and is of a
viscosity appropriate for the selected drop ejector. For example, in
thermal ink jet printing systems, a preferred liquid vehicle is water. In
other drop ejectors, such as those employing continuous stream
processes, piezoelectric ink jet printers, acoustic ink jet printers, and the
like, other liquids can also be employed, such as hydrocarbons, glycols,
ethers, sulfones such as sulfolane, pyrrolidinones such as 2-pyrrolidinone
and N-methyl pyrrolidinone, other dipolar aprotic solvents, and the like,
as well as mixtures thereof. The fixing composition can also contain
other components which might improve its performance as an ink jet
ink, such as humectants, penetrants, cosolvents, jetting aids, or the like,
set forth in more detail hereinbelow. Typically, the fixative is a mixture
of a weakly acidic reagent and a reducing agent. The acid is present
in the fixing composition in an amount sufficient to neutralize base from
the developing composition, coloring composition, and/or oxidizing
composition in the initially formed image. The reducing agent is present
in the fixing composition in an amount sufficient to quench excess
oxidizing components in the initially formed image. The fixing
composition typically contains the flxative mixture in an amount of from
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CA 02472355 2004-07-20
about 0.1 to about 10 percent by weight of the fixing composition,
preferably from about 1 to about 5 percent by weight of the ftxing
composition, although the amount can be outside of these ranges.
Examples of suitable weakly acidic fixative components
include ascorbic acid, phthalic acid, benzoic acid, acetic acid, maleic
acid succinic acid, poly(acrylic acid), poly(methacrylic acid),
copoly(styrene/maleic acid), copoly(methylvinylether/maleic acid),
and the like, as well as mixtures thereof. Examples of suitable reducing
fixative components include ascorbic acid, sodium tulfite, sodium
bisulfite, glucose and other reducing sugars, and the like, as well as
mixtures thereof.
As stated hereinabove, the developing composition, the
oxidizing composition, the coloring composition, and the fixing
composition (hereinafter collectively referred to as inks or ink
compositions of or for the present invention) all generally have
compositions which render them suitable for use as ink jet inks in an ink
jet printing apparatus. Ink jet inks generally contain an aqueous liquid
vehicle. The liqUid vehicle can consist solely. of water, or it can
comprise a mixture of water and a water soluble or water miscible
organic component, such as ethylene glycol, propylene glycol,
diethylene glycols, glycerine, dipropylene glycols, polyethylene glycols,
polypropylene glycols, amides, ethers, urea, substituted ureas, ethers,
carboxylic acids and their salts, esters, alcohols, organosulfides,
organosulfoxides, sulfones (such as suifoiane), alcohol derivatives,
carbitol, butyl carbitol, cellusolve, tripropyiene glycoi monomethyl
ether, ether derivatives, amino alcohols, ketones, N-
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methylpyrrolidinone, 2-pyrrolidinone, cyclohexylpyrrolidone,
hydroxyethers, amides, sulfoxides, lactones, polyelectrolytes, methyl
sulfonylethanol, imidazole, betaine, and other water soluble or water
miscible materials, as well as mixtures thereof. When mixtures of water
and water soluble or miscible organic liquids are selected as the liquid
vehicle, the water to organic ratio typically ranges from about 100:0 to
about 30:70, and preferably from about 97:3 to about 40:60. The non-
water component of the liquid vehicle generally serves as a
humectant or cosolvent which has a boiling point higher than that of
water (100 C). In the ink compositions of the present invention, the
liquid vehicle is typically present in an amount of from about 80 to
about 99.9 percent by weight of the ink, and preferably from about 90
to about 99 percent by weight of the ink, although the amount can be
outside these ranges.
Other optional additives to the inks of the present invention
include pH controlling agents such as acids or, bases, phosphate salts,
carboxylates salts, sulfite salts, amine salts, and the like, present in an
amount of from 0 to about 1 percent by weight of the ink and
preferably from about 0.01 to about 1 percent by weight of the ink, or
the like. One or more surfactants or wetting agents can also be added
to the ink. These additives may be of the cationic, anionic, or nonionic
types. Suitable surfactants and wetting agents include sodium lauryl
sulfate, TamolO SN, TamolO LG, those of the Triton series available
from Rohm and Haas Company, those of the Marasperse@ series, those
of the Igepal0 series available from GAF Company, those of the
Tergitol series, and other commercially available surfactants. These
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CA 02472355 2004-07-20
surfactants and wetting agents are present in any desired or effective
amounts, generally from 0 to about 15 percent by weight of the ink,
and preferably from about 0.01 to about 8 percent by weight of the
ink, although the amount can be outside of this range.
One example of an additive to the inks of the present
invention is a polymeric additive consisting of two polyalkylene oxide
chains bound to a central bisphenol-A-type moiety. This additive is of
the formula
Ri
H- (OR4)x-O a C O O-(R3O)y -H
2
wherein Ri and R2 are independently seiected from the group
consisting of hydrogen, alkyl groups with from 1 to about 8 carbon
atoms, such as methyl, ethyl, propyl, and the like, and alkoxy groups
with from 1 to about 8 carbon atoms, such as methoxy, ethoxy, butoxy,
and the like, R3 and R, are independently selected from the group
consisting of alkyl groups with from 1 to about 4 carbon atoms, and x
and y are each independently a number of from about 100 to about
400, and preferably from about 100 to about 200. Generally, the
molecular weight of the polyalkylene oxide polymer is from about
14,000 to about 22,000, and preferably from about 15,000 to about
20,000. although the molecular weight can be outside this range.
Materials of this formula are commercially available; for example,
Carbowax M20, a polyethylene oxide/bisphenol-A polymer of the
above formula with a molecular weight of about 18,000, available from
Union Carbide Corporation, Danbury, CT, is a suitable polymeric
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CA 02472355 2004-07-20
additive for the inks of the present invention. In addition, compounds
of the above formula can be prepared by the methods disclosed in
Polyethers, N. G. Gaylord, John Wiley & Sons, New York (1963) and
"Laboratory Synthesis of Polyethylene Glycol Derivatives," J. M. Harris, J.
Molecular Science - Rev. Macromol. Chem. Phys., C25(3), 325-373
(1985). The polyalkylene oxide additive is generally present in the ink in
an amount of at least about 1 part per million by weight of the ink.
Typically, the polyalkylene oxide additive is present in amounts of up to
1 percent by weight of the ink, and preferably in amounts of up to 0.5
percent by weight of the ink; larger amounts of the additive may
increase the viscosity of the ink beyond the desired level, but larger
amounts can be used in applications wherein increased ink viscosity is
not a problem. Inks containing these additives are disclosed in U.S.
Patent 5,207,825.
The ink compositions of the present invention are generally
of a viscosity suitable for use in thermal ink jet printing processes. At
room temperature (i.e., about 25 C), typically, the ink viscosity is no
more than about 10 centipoise, and preferably is from about 1 to
about 5 centipoise, more preferably from about 1 to about 4
centipoise, although the viscosity can be outside this range, particularly
for applications such as acoustic ink jet printing.
ink compositions of the present invention can be of any
suitable or desired pH. At least one of the developing composition,
coloring composition, and oxidizing composition is sufficiently alkaline
to
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CA 02472355 2004-07-20
foster the coupling reaction between the color developer and the dye
coupler.
Ink compositions suitable for ink jet printing can be
prepared by any suitable process. Typically, the inks are 'prepared by
simple mixing of the ingredients. One process entails mixing all of the
ink ingredients 'together and filtering the mixture to obtain an ink. Inks
can be prepared by mixing the ingredients, heating if desired, and
filtering, followed by adding any desired additional additives to the
mixture and mixing at room temperature witi'i moderate shaking until a
homogeneous mixture is obtained, typically from about 5 to about 10
minutes. Alternatively, the optional ink additives can be mixed with the
other ink ingredients during the ink preparation process, which takes
place according to any desired procedure, such as by mixing all the
ingredients, heating if desired, and fiitering.
In one specific embodiment of the present invention, the
ink jet printing apparatus employs a thermal ink jet process wherein the
ink in the nozzles is selectively heated in an imagewise pattern, thereby
causing droplets of the ink to be ejected in imagewise pattem. In
another specific embodiment, the printing apparatus employs an
acoustic ink jet process, wherein droplets of the ink are caused to be
ejected in imagewise pattern by acoustic beams. Other methods, such
as piezoelectric drop on demand ink jet printing, continuous stream ink
jet printing, hot melt ink jet printing, or the like, can also be employed.
Any suitable substrate or recording sheet can be
employed, including plain papers such as XeroxV 4024 papers, Xerox9
image Series papers, Courtland 4024 DP paper, ruled notebook paper,
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CA 02472355 2004-07-20
bond paper, siiica coated papers such as Sharp Company silica
coated paper, JuJo paper, and the like, transparency materials,
fabrics, textile products, plastics, polymeric films, inorganic substrates
such as metals and wood, and the like. In a preferred embodiment,
the process entails printing onto a porous or ink absorbent substrate,
such as plain paper. In embodiments of the present invention wherein
special substrates or receiver sheets are used, it can be advantageous
to use a paper coated with absorbing layers for specific dye couplers.
As disclosed in, for example, Japanese Patent Publication JP 9030107 A,
when coloring agents are localized at a specific depth in the receiving
sheet, improved color reproduction can be achieved because agents
of different color tone do not mingle at the same depth in the
absorbing layer.
The specific embodiments of the present invention which
enable production of gray-level images have been illustrated
hereinabove in the specific context of photographic, including color
photographic, materials and development processes. These
embodiments of the present invention, namely (1) providing a
multiplicity of intensity or "gray" levels within a particular color by
controlling the time between the point at which the developing
composition, oxidizing composition, and coloring composition all come
together and the point at which the fixing composition is deposited; (2)
providing a multiplicity of intensity or "gray" levels within a particular
color by jetting fixed amounts of one of (a) the developing
composition, (b) the coloring composition, or (c) the oxidizing
composition onto the substrate in combination with varying amounts
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CA 02472355 2004-07-20
the other two compositions, with the limited composition being present
in reaction limiting quantities with respect to the other two
compositions; and (3) jetting the developing composition, coloring
composition(s), and oxidizing composition in an imagewise pattern so
that the overlap of droplets of these three compositions is controlled,
thereby modulating pixel size to realize variable spot sizes, can also be
realized by a multiplicity of other specific chemistries. In some of these
embodiments, no fixative is needed; in other embodiments, only two
color forming liquid- compositions are used instead of three. One
embodiment of the present invention is directed to -a process which
comprises (a) incorporating into an ink jet printing apparatus (1) a color
forming composition comprising a liquid vehicle and at least one color
forming agent; and (2) a reacting composition comprising a liquid
vehicle and at Ieast one material capable of reacting with the color
forming agent to cause a desired color to form; (b) causing droplets of
the color forming composition to be ejected in an imagewise pattern
onto the substrate; and (c) causing droplets of the reacting
composition to be ejected in an imagewise pattern onto the substrate;
wherein the process results in at least some portions of the substrate
bearing images comprising both the color forming composition and the
reacting composition, said portions forming a printed image, wherein at
time Ti, the color forming composition has formed an image on the
substrate, at time Tz, the reacting composition is deposited onto a first
portion Pr of the image, -and at time T3, the reacting composition is
deposited onto a second portion P2 of the image, wherein time period
Ti to T2 is less than time period Ti to Ts, thereby resulting in second
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CA 02472355 2004-07-20
portion P2 having a different color intensity from first portion Pi. Another
embodiment of the present invention is directed to a process which
comprises (a) incorporating into an ink jet printing apparatus (1) a color
forming composition comprising a liquid vehicle and at least one color
forming agent; and (2) a reacting composition comprising a liquid
vehicle and at least one material capable of reacting with the color
forming agent to cause a desired color to form; (b) causing droplets of
the color forming composition to be ejected in an imagewise pattem
onto the substrate; and (c) causing droplets of the reacting
composition to be ejected in an imogewise pattern onto the substrate;
wherein the process results in at least some portions of the substrate
bearing images comprising both the color forming composition and the
reacting composition, said portions forming a printed image, wherein
one of (i) the color forming composition and (ii) the reacting
composition is applied to the substrate in fixed volumes per pixel, and
the other of (i) and (ii) is applied to the substrate in varying volume per
pixel, thereby varying the intensity of color of the printed image. Yet
another embodiment of the present invention is directed to a process
which comprises (a) incorporating into an ink jet printing apparatus (1)
a coior forming composition comprising a liquid vehicle and at least
one color forming agent; and (2) a reacting composition comprising a
liquid vehicle and at least one material capable of reacting with the
color forming agent to cause a desired color to form; (b) causing
droplets of the color forming composition to be ejected in an
imagewise pattern onto the substrate; and (c) causing droplets of the
reacting composition to be ejected in an imagewise pattern onto the
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substrate; wherein the process results in at least some portions of the
substrate bearing images comprising both the color forming
composition and the reacting composition, said portions forming a
printed image, wherein droplets of the color forming composition and
droplets of the reacting composition are applied to the substrate in an
imagewise pattern so that droplets of color forming composition and
reacting composition overiap in a controlled pattem, thereby forming
spots of varying sizes on the substrate, said spots being formed in areas
where droplets of the color forming composition and reacting
, composition overlap.
For example, the present invention includes embodiments
wherein more than one color forming agent is combined into a single
' ink" or liquid composition for printing. For example, the color developer
and the dye coupler can be included in a single 'ink' or liquid
composition, thereby eliminating the need for a separate developing
composition and the need for a separate printhead and cartridge for
printing said developing composition. In this embodiment, the use of
quinone color developers may be preferred over diamine color
developers in view of the higher reactivity (and potential unstability in
this embodiment) of the diamines.
In addition, dye developer molecules, commonly used -in
instant photography, can be used in place of distinct color developer
and dye coupler molecules. In this embodiment, the color developer
and the dye coupler are covalently bonded in a single molecule.
Otherwise, the process is analogous to that described hereinabove with
respect to materials commonly used in conventional photography.
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Further information on the dye developer molecules and processes for
the use thereof is disclosed in, for example, "Color Photography,
Instant," by Vivian K Walworth and Stanley H. Mervis in The
Encyclopedia of Chemical Technology, 4th Edition, Vol. 6, pp.1003-
1048, John Wiley & Sons, New York (1993); U.S. Patent 3,443,940; U.S.
Patent 2,983,606; U.S. Patent 3,255,001; U.S. Patent 3,201,384; U.S. Patent
3,246,985; U.S. Patent 3,857,855; U.S. Patent 4,264,701; M. Idelson, I. R.
Karday, B. H. Mark, D. O. Richter, and V. H. Hooper, Inorg. Chem. 6, 450
(1967); E. M. Idelson, Dyes and Pigments 3, 191 (1982); and H. G. Rogers,
E. M. Idelson, R. F. W. Cieciuch, and S. M. Bloom, J. Photogr. Sci. 22, 138
(1974).
Further, leuco or vat dyes, which are typically colorless
unless and until reacted with an oxidizing agent or pH altering agent,
can be used in combination with oxidative reagents or pH-altering
reagents to visualize them. In this embodiment, no fixative is needed.
Otherwise, the process is analogous to that described hereinabove
with respect to materials commonly used in conventional
photography. Further information on leuco and vat dyes and
processes for the use thereof is disclosed in, for example, IBM Technical
Disclosure Bulletin, Vol. 23, No. 4, p. 1387 (September 1980); U.S. Patent
1,055,115; British Patent 15055/12; and German Patent 257,167.
Additionally, metal vanadates and polyphenolic
compounds, such as gallic acid, tannic acid, dihydroxybenzene
carboxylic acids, or dihydroxynaphthalene carboxylic acids, can be
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used to create durable black images. Otherwise, the process is
analogous to that described hereinabove with respect to materials
commonly used in conventional photography. Further information on
metal vanadates and polyphenolics and processes for the use thereof
is disclosed in, for example, Japanese Patent Publication JP 77049366 8,
British Patent Publication GB 1398334, and German Patent Publication
DE 2505077.
Specific embodiments of the invention will now be
described in detail. These examples are intended to be illustrative, and
the invention is not limited to the materials, conditions, or process
parameters set forth in these embodiments. All parts and percentages
are by weight unless otherwise indicated.
EXAMPLE I
A developer composition was prepared by admixing 5
parts by weight CD-3 developer (4-(N-ethyi-N-2-
methanesulfonyiaminoethyl)-2-methyl-phenylenediamine sesquisulfate
monohydrate, obtained from Eastman Kodak Co., Rochester, NY), 70
parts by weight of deionized water, 11 parts by weight of tripropylene
glycol monomethyl ether (DOWANOL TPM, obtained from Dow
Chemical Co.), 10 parts by weight of dipropylene glycol, 0.05 parts by
weight of polyethylene' oxide (poly(ethylene gfycol)-bisphenol A
diglycidyl ether adduct, molecular weight 18,500, obtained from
Polysciences), and 3 parts by weight of potassium carbonate.
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An oxidizing composition was prepared by admixing 74
parts by weight of deionized water, 11 parts by weight of tripropylene
glycol monomethyl ether (DOWANOLO TPM, obtained from DoW
Chemical Co.), 10 parts by weight of dipropylene glycol, 0.05 parts by
weight of polyethylene oxide (poly(ethylene glycol)-bisphenol A
diglycidyl ether adduct, molecular weight 18,500, obtained from
Polysciences), 3 parts by weight of potassium carbonate, and 3 parts
by weight of potassium peroxodisulfate (K2S208).
A cyan coloring composition was prepared by admixing 74
parts by weight of deionized water, 11 parts by weight of tripropylene
glycol monomethyl ether (DOWANOLO TPM, obtained from Dow
Chemical Co.), 10 parts by weight of dipropylene glycol, 0.05 parts by
weight of polyethylene oxide (poly(ethylene glycol)-bisphenol A
diglycidyl ether adduct, molecuiar weight 18,500, obtained from
Polysciences), and 5 parts by weight of a a-naphthol cyan dye coupler
(N-(2-acetamidophenethyl)-1-hydroxy-2-naphthamide, obtained from
Fisher Scientific (ACROS ORGANICS), Pittsburgh, PA). A magenta
coloring composition was made by the same process except that the
dye coupler used was 5 parts by weight of a pyrazolinone magenta
dye coupler (1-(2,4,6-trichlorophenyl)-3-(p-nitroanilino)-2-pyrazoline-5-
one, obtained from Fisher Scientific (ACROS ORGANICS), Pittsburgh, PA).
A yellow coloring composition was made by the same process except
that the dye coupler used was 5 parts by weight of a(3-
ketocarboxamide yellow dye coupler (2-benzoylacetanilide, obtained
from Fisher Scientific (ACROS ORGANICS), Pittsburgh, PA).
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A fixing compositicn was prepared by admixing 70 parts by
weight of deionized water, i 1 parts by weight of tripropylene glycol
monornethyi ether (DOWANOLB TPM, obtained from Dow Chemical
Co.), 10 parts by weight of dipropylene glycol, 0.05 parts by weight of
polyethylene oxide (poly(ethylene glycol)-bisphenol A diglycidyl ether
adduct, molecular weight 18,500, obtained from Polysciences), 5 parts
by weight of poly(methyl vinyl ether/maleic acid) (GANTREZ MS-955,
obtained from GAF Corp., Wayne, NJ), and 4 parts by weight of sodium
sulfite (Na2SO3).
A microliter syringe was then used to deposit controlled
volumes of the developer composition onto XEROX Color Xpressionse
paper. Stoichiometric quantities of the oxidizing composition and the
cyan coioring composition were then deposited directly onto the spots
containing the developer composition to yield intensely colored cyan
spots.
The process was repeated with varying volumes of the
oxidizing composition to yield cyan colored spots of varying intensity.
The process was repeated so that the droplets of
developing composition, oxidizing composition, and coloring
composition did not overlap completely. Intensely colored cyan spots
of fractional size (compared to those obtained with 100 percent
dropiet overlap) were obtained only in those areas wherein the
droplets of developing composition, oxidizing composition, and
coloring composition overlapped.
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The reactions were quenched by deposition of a
stoichiometric excess of the fixing composition onto the developed
spots.
Other embodiments and modifications of the present
invention may occur to those of ordinary skill in the art subsequent to a
review of the information presented herein; these embodiments and
modifications, as well as equivalents thereof, are also included within
the scope of this invention.
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