U.S. patent application number 10/034281 was filed with the patent office on 2003-07-10 for materials for reducing inter-color gloss difference.
This patent application is currently assigned to Eastman Kodak Company. Invention is credited to Chen, Huijuan D., Han-Adebekun, Gang C., Reczek, James A..
Application Number | 20030128262 10/034281 |
Document ID | / |
Family ID | 21875412 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030128262 |
Kind Code |
A1 |
Chen, Huijuan D. ; et
al. |
July 10, 2003 |
MATERIALS FOR REDUCING INTER-COLOR GLOSS DIFFERENCE
Abstract
An ink jet ink set and recording element combination comprising:
A) a porous ink jet recording element having a 60.degree. specular
gloss of at least about 5; and B) a pigment based ink jet ink set
comprising at least two inks; wherein the RGD value is less than
40% and RGV value among inks is less than 10% when 60.degree. is
used as the specular angle; the RGD and RGV values are calculated
according to Equations (A) and (B), respectively: 1 RGD % = I = 1 N
Gloss ( Imaged Areas ) I - Gloss ( Non Imaged Areas I = 1 N Gloss (
Imaged Areas ) I Equation ( A ) RGV ( % ) = I = 1 N | ( Gloss (
Imaged Area ) I - AG ) | AG / N Where AG = I = 1 N Gloss ( Imaged
Area ) I N Equation ( B ) I is a variable which identifies a
certain color patch used in the evaluation, N is the total number
of color patches used in the evaluation.
Inventors: |
Chen, Huijuan D.; (Webster,
NY) ; Han-Adebekun, Gang C.; (Rochester, NY) ;
Reczek, James A.; (Rochester, NY) |
Correspondence
Address: |
Paul A. Leipold
Patent Legal Staff
Eastman Kodak Company
343 State Street
Rochester
NY
14650-2201
US
|
Assignee: |
Eastman Kodak Company
|
Family ID: |
21875412 |
Appl. No.: |
10/034281 |
Filed: |
December 28, 2001 |
Current U.S.
Class: |
347/100 |
Current CPC
Class: |
B41M 5/52 20130101; B41M
5/5218 20130101; B41M 5/5236 20130101; B41M 5/5254 20130101; C09D
11/40 20130101; B41M 5/508 20130101 |
Class at
Publication: |
347/100 |
International
Class: |
G01D 011/00 |
Claims
What is claimed is:
1. An ink jet ink set and recording element combination comprising:
A) a porous ink jet recording element having a 60.degree. specular
gloss of at least about 5; and B) a pigment based ink jet ink set
comprising at least two inks; wherein the RGD value is less than
40% and RGV value among inks is less than 10% when 60.degree. is
used as the specular angle; the RGD and RGV values are calculated
according to Equations (A) and (B), respectively: 4 RGD % = I = 1 N
Gloss ( Imaged Areas ) I - Gloss ( Non Imaged Areas I = 1 N Gloss (
Imaged Areas ) I Equation ( A ) RGV ( % ) = I = 1 N | ( Gloss (
Imaged Area ) I - AG ) | AG / N Where AG = I = 1 N Gloss ( Imaged
Area ) I N Equation ( B ) I is a variable which identifies a
certain color patch used in the evaluation, N is the total number
of color patches used in the evaluation.
2. The combination of claim 1 wherein the RGD value is less than
30% and RGV value among inks is less than 7% when the specular
angle is 60.degree..
3. The combination of claim 1 wherein the porous ink jet recording
element further comprises a support having thereon a porous
ink-receiving layer.
4. The combination of claim 3 wherein said porous ink-receiving
layer comprises from about 20% to about 95% by weight of inorganic
particles and from about 5% to about 80% by weight of a polymeric
binder; based on the combined weight of the inorganic particles and
the binder.
5. The combination of claim 4 wherein said inorganic particles
comprise silica, alumina, titanium dioxide, clay, calcium
carbonate, barium sulfate or zinc oxide.
6. The combination of claim 4 wherein said polymeric binder is
gelatin, poly(vinyl alcohol), poly(vinyl pyrrolidinone) or
poly(vinyl acetate) or copolymers thereof.
7. The combination of claim 3 wherein said porous ink-receiving
layer contains organic particles.
8. The combination of claim 3 wherein said porous ink-receiving
comprises a polymeric open-pore membrane.
9. The combination of claim 3 wherein said porous ink-receiving
layer further contains a crosslinker capable of crosslinking said
binder.
10. The combination of claim 3 wherein said support is
polyethylene-coated paper.
11. The combination of claim 1 wherein said pigment is a yellow
pigment, a cyan pigment, a magenta pigment, a black pigment, a
white pigment, a violet pigment, a green pigment, or an orange
pigment.
12. The combination of claim 11 wherein said yellow pigment is C.I.
Pigment Yellow 155 or C.I. Pigment Yellow 74.
13. The combination of claim 11 wherein said cyan pigment is C.I.
Pigment Blue 15:3 or
bis(phthalocyanylalumino)tetraphenyldisiloxane.
14. The combination of claim 11 wherein said magenta pigment is
C.I. Pigment Red 122.
15. The combination of claim 11 wherein said black pigment is C.I.
Pigment Black 7.
16. The combination of claim 1 wherein the inks in the ink set
comprise non-film forming particles.
17. The combination of claim 16 wherein the non-film forming
particles are between 0.03 and 0.5 micron.
18. The combination of claim 16 where the non-film forming
particles are inorganic particles.
19. The combination of claim 18 wherein the inorganic particles are
silica, alumina, titinium dioxide, zircona and clay, calcium
carbonate, barium sulfate or zinc oxide.
20. The combination of claim 16 wherein the non-film forming
particles are organic polymeric particles.
21. The combination of claim 20 wherein the organic polymeric
particle is a polyurethane, a polyacrylic, or a polyester with a Tg
of greater than 60.degree. C.
22. The combination of claim 1 wherein the ink in the ink set
further comprises a film forming polymer resin.
23. The combination of claim 22 wherein the film forming polymer
resin is water dispersible.
24. The combination of claim 22 wherein the film forming polymer
resin is a polyester, a polyurethane or a polyacrylic.
25. The combination of claim 24 wherein the polyester is a
sulfonated polyester ionomer.
26. The ink set of claim 1 imagewise disposed on the receiver of
claim 1.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application relates to commonly assigned copending
application Ser. No. ______ (Docket 83710) entitled INK JET INK
SET; application Ser. No. ______ (Docket 83886) entitled INK JET
INK SET/RECEIVER COMBINATION; application Ser. No. ______ (Docket
83899) entitled A METHOD OF SELECTING INK JET INKS IN A COLOR SET
and application Ser. No. ______ (Docket 83900) entitled A METHOD OF
SELECTING INK JET INKS IN A COLOR SET filed simultaneously
herewith. These copending applications are incorporated by
reference herein for all that they contain.
FIELD OF THE INVENTION
[0002] This invention relates to a combination of ink jet color ink
set and a porous ink jet recording element for ink jet printing
that provides images with improved gloss difference in imaged and
non-imaged areas as well as inter-color gloss difference.
BACKGROUND OF THE INVENTION
[0003] In a typical ink jet recording or printing system, ink
droplets are ejected from a nozzle at high speed towards a
recording element or medium to produce an image on the medium. The
ink droplets, or recording liquid, generally comprise a recording
agent, such as a dye or pigment, and a large amount of solvent. The
solvent, or carrier liquid, typically is made up of water and an
organic material such as a monohydric alcohol, a polyhydric alcohol
or mixtures thereof.
[0004] An ink jet recording element typically comprises a support
having on at least one surface thereof an ink-receiving or
image-receiving layer, and includes those intended for reflection
viewing, which have an opaque support, and those intended for
viewing by transmitted light, which have a transparent support.
[0005] An important characteristic of ink jet recording elements is
their need to dry quickly after printing. To this end, porous
recording elements have been developed which provide nearly
instantaneous drying as long as they have sufficient thickness and
pore volume to effectively contain the liquid ink. For example, a
porous recording element can be manufactured by cast coating, in
which a particulate-containing coating is applied to a support and
is dried in contact with a polished smooth surface.
[0006] One of the major disadvantages of the current ink jet
recording element is "differential gloss", particular on images
printed using pigment-based inks. In pigment-based inks, the
colorant exists as discrete particles. These pigment particles are
usually treated with addenda known as dispersants or stabilizers
which serve to keep the pigment particles from agglomerating and/or
settling out. Therefore, when the pigment-based inks are printed on
recording elements having glossy surfaces, the inks on the imaged
areas tend to stay on the surface of the receiver. "Differential
gloss" may include both "image and non-image differential gloss"
and "inter-color differential gloss". "Image and non-image image
differential gloss" describes the image artifact where the gloss of
the non-imaged areas is very different from that of imaged areas.
"Inter-color differential gloss" describes the image artifact where
the gloss levels of imaged areas of different colors are very
different from each other. Both types of image quality defects can
be quite noticeable, even to ordinary observers. Although not
designed to improve "differential gloss", one possible solution to
this problem is to cover the entire receiver with a protective
layer through techniques such as laminating the printed image, or
fusing the top fusible polymeric layer in receivers to a continuous
overcoat layer, such as those disclosed in U.S. patent application,
Ser. No. 09/954,779, filed on Sep. 18, 2001 of Wexler, or coating a
protective layer on the imaged areas as described in EP1057646 and
EP1048466. However, all these approaches involve separate steps
after printing, making the entire process complex and costly.
[0007] What the art needs is a way to minimize gloss level
variations in imaged and non-imaged areas as well as those among
different colors when the various inks are deposited and dried on a
receiver. This should be done as part of the printing process and
not as a separate step after printing.
SUMMARY OF THE INVENTION
[0008] The present invention provides an ink jet color ink set and
receiver combination that is capable of producing images wherein
the gloss level variations between imaged and non-imaged areas as
well as that among different colors in the color image are
simultaneously minimized. The gloss variation is judged after the
ink is deposited and dried on a receiver, but the invention is a
part of the ink and receiver selection and printing process; not a
separate step after printing.
[0009] In accordance with the invention, the gloss level of the ink
is predetermined, as measured from single color patches on a
receiver. The gloss level of the receiver is also determined under
a similar measurement condition. The gloss level variability among
different inks as well as the relative gloss difference between the
imaged and non-imaged areas are both calculated. By simultaneously
keeping the relative gloss difference of the ink and receiver
combination as well as the gloss variability with a certain range,
the quality of the image is improved.
[0010] Hence, the present invention discloses an ink jet ink set
and recording element combination comprising:
[0011] A) a porous ink jet recording element having a 60.degree.
specular gloss of at least about 5; and
[0012] B) a pigment based ink jet ink set comprising at least two
inks;
[0013] wherein the RGD value is less than 40% and RGV value among
inks is less than 10% when 60.degree. is used as the specular
angle; the RGD and RGV values are calculated according to Equations
(A) and (B), respectively: 2 RGD % = I = 1 N Gloss ( Imaged Areas )
I - Gloss ( Non Imaged Areas I = 1 N Gloss ( Imaged Areas ) I
Equation ( A ) RGV ( % ) = I = 1 N | ( Gloss ( Imaged Area ) I - AG
) | AG / N Where AG = I = 1 N Gloss ( Imaged Area ) I N Equation (
B )
[0014] I is a variable which identifies a certain color patch used
in the evaluation,
[0015] N is the total number of color patches used in the
evaluation.
[0016] The advantage of the invention is that it minimizes gloss
difference between the imaged and non-imaged areas as well as among
different colors in a printed color image on the receiver and this
is done as a part of the initial printing process.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Ink Set and Receiver Gloss Matching
[0018] Gloss, commonly referred to as specular gloss, of a surface
is defined as its degree of approach to a mirror-like surface. It
is a measure of the amount of energy reflected at a reflection
angle equal to or near the angle of incidence. Specular gloss can
be measured in terms of gloss units, at several angles, e.g.
20.degree., 30.degree., 45.degree., 60.degree., 75.degree. and
80.degree. from the surface normal. Gloss meters are used to
measure the gloss of a sample at various angles. The BYK-Gardner
micro-TRI-glossmeter is an example of such an instrument.
[0019] The porous receiver used in this invention refers to an
ink-recording element having a 60.degree. specular gloss level of 5
or higher. An ink jet recording element typically comprises a
support having on at least one surface thereof an ink-receiving or
image-forming layer, the ink-receiving layer is a porous layer
which imbibes the ink via capillary action. The gloss level of the
receiver can be achieved through receiver layer design and the
properties of components in each layer, such as particle sizes of
the surface coating, surface roughness of the support, etc. For
example, possibly by varying the inorganic particle sizes in the
ink-receiving layer, 60.degree. gloss level of Kodak Instant-Dry
Photographic Glossy Media Cat 8103137 has reached a value of about
64. In comparison, the 60.degree. gloss level of Epson Photoglossy
Paper.RTM. SP91001 is only about 34. In addition, as known in the
art, gloss level can be modified by changing the surface smoothness
of the support within a receiver. For example, by changing the
surface smoothness of the chill roll (e.g. a F-surface versus a
textured E-surface) used in the resin coating step of the support
manufacturing, Kodak Instant-Dry Photographic media has a wide
range of gloss level from a 60.degree. gloss level of about 30
(Satin Media Cat 8648263) to that of 64 (Glossy Media Cat
8103137).
[0020] When inks are printed on a receiver, the gloss level of the
printed image is determined by both ink and receiver. Ink
properties, such as, for example, the refractive index of polymers
in the inks, the film forming property of the polymers in the inks
after printing, and the ink load deposit on the receiver, may
individually or in combination influence the gloss of a printed
image. For pigment-based inks, pigment particle size and
distribution, and the use of non-film forming particles can also
have a significant impact on the gloss levels, such as those
disclosed in U.S. patent application, Ser. No. ______ (Docket
83710), of Chen et al. filed simultaneously herewith. The present
inventors have discovered that when the gloss level of the receiver
is designed to match the gloss levels generated from the ink set,
the printed images have less observable differential gloss between
imaged and non-imaged areas. Furthermore, by keeping the gloss
level variability among different inks with a certain range, the
printed images have less observable inter-color gloss difference.
Both of them help to improve the image quality of the overall
print.
[0021] In this invention, the match between the receiver and ink
set is characterized by a parameter called Relative Gloss
Difference (RGD) as defined in Equation A. The inter-color gloss
difference is characterized by a parameter called Relative Gloss
Variability (RGV), which is derived from Average Gloss (AG) as
defined in Equation B. 3 RGD % = I = 1 N Gloss ( Imaged Areas ) I -
Gloss ( Non Imaged Areas I = 1 N Gloss ( Imaged Areas ) I Equation
( A ) RGV ( % ) = I = 1 N | ( Gloss ( Imaged Area ) I - AG ) | AG /
N Where AG = I = 1 N Gloss ( Imaged Area ) I N Equation ( B )
[0022] I is a variable which identifies a certain color patch used
in the evaluation,
[0023] N is the total number of color patches used in the
evaluation.
[0024] In this invention, RGD and RGV are obtained based on the
following procedure: load into a printer a selected ink set
comprising at least 2 inks and then print onto the recording
elements of this invention using a test image. The test image is
designed to include single color patches of Dmax density (100% dot
coverage). The size of the patch needs to be large enough, for
example, approximately 3 by 3 centimeters in size for uniform gloss
measurement. The dot coverage is also important in order to
minimize the gloss contribution from local areas not covered by the
inks at the pixel level. Usually, a reflection density of 1.5
(Dmax) can be achieved at 100% dot coverage. The color used in the
evaluation may include any combination of colors capable of being
generated by the selected ink set, such as primary colors (for
example, cyan, magenta, yellow, black) or, optional secondary
colors (for example, red, green, blue), process black (a
combination of cyan, magenta and yellow) or 400% black (a
combination of cyan, magenta, yellow and black). After allowing the
printed test images to dry for 24 hours at ambient temperature and
humidity, the gloss level at a certain specular angle (for example,
60 degree) of each color patch is then measured, using a gloss
meter, for example, the BYK-Gardner micro-TRI-glossmeter. Under the
same condition, the gloss level of the receiver (non-imaged areas)
is also measured.
[0025] It is preferred that the combination of ink set and the
porous ink jet recording element is capable of generating RGD
values of less than 40% (when 60 degree is used as the specular
angle) and RGV value among inks of less than 10% (when 60 degree is
used as the specular angle). It is further preferred that the
combination of ink set and the porous ink jet recording element is
capable of generating RGD values of less than 30% (when 60 degree
is used as the specular angle) and RGV value among inks of less
than 7% (when 60 degree is used as the specular angle).
[0026] Ink Jet Recording Element
[0027] The support for the ink jet recording element used in the
invention can be any of those usually used for ink jet receivers,
such as resin-coated paper, paper, polyesters, or microporous
materials such as polyethylene polymer-containing material sold by
PPG Industries, Inc., Pittsburgh, Pa. under the trade name of
Teslin.RTM., Tyvek.RTM. synthetic paper (DuPont Corp.), and
OPPalyte.RTM. films (Mobil Chemical Co.) and other composite films
listed in U.S. Pat. No. 5,244,861. Opaque supports include plain
paper, coated paper, synthetic paper, photographic paper support,
melt-extrusion-coated paper, and laminated paper, such as biaxially
oriented support laminates. Biaxially oriented support laminates
are described in U.S. Pat. Nos. 5,853,965; 5,866,282; 5,874,205;
5,888,643; 5,888,681; 5,888,683; and 5,888,714, the disclosures of
which are hereby incorporated by reference. These biaxially
oriented supports include a paper base and a biaxially oriented
polyolefin sheet, typically polypropylene, laminated to one or both
sides of the paper base. Transparent supports include glass,
cellulose derivatives, e.g., a cellulose ester, cellulose
triacetate, cellulose diacetate, cellulose acetate propionate,
cellulose acetate butyrate; polyesters, such as poly(ethylene
terephthalate), poly(ethylene naphthalate),
poly(1,4-cyclohexanedimethylene terephthalate), poly(butylene
terephthalate), and copolymers thereof, polyimides; polyamides;
polycarbonates; polystyrene; polyolefins, such as polyethylene or
polypropylene; polysulfones; polyacrylates; polyetherimides; and
mixtures thereof. The papers listed above include a broad range of
papers, from high end papers, such as photographic paper to low end
papers, such as newsprint. In a preferred embodiment,
polyethylene-coated paper is employed.
[0028] The support used in the invention may have a thickness of
from about 50 to about 500 .mu.m, preferably from about 75 to 300
.mu.m. Antioxidants, antistatic agents, plasticizers and other
known additives may be incorporated into the support, if
desired.
[0029] The ink-receiving layer for the ink jet recording element
used in the invention can be porous. In a preferred embodiment of
the invention, the porous ink-receiving layer contains particles.
Examples of particles useful in the invention include alumina,
boehmite, clay, calcium carbonate, titanium dioxide, calcined clay,
aluminosilicates, silica, barium sulfate, or polymeric beads. The
particles may be porous or nonporous. In a preferred embodiment of
the invention, the particles are metallic oxides, preferably fumed.
While many types of inorganic and organic particles are
manufactured by various methods and commercially available for an
image-receiving layer, porosity of the ink-receiving layer is
necessary in order to obtain very fast ink drying. The pores formed
between the particles must be sufficiently large and interconnected
so that the printing ink passes quickly through the layer and away
from the outer surface to give the impression of fast drying. At
the same time, the particles must be arranged in such a way so that
the pores formed between them are sufficiently small that they do
not scatter visible light.
[0030] The particles may be in the form of primary particles, or in
the form of secondary aggregated particles. The aggregates are
comprised of smaller primary particles about 7 to about 40 nm in
diameter, and being aggregated up to about 300 nm in diameter. The
pores in a dried coating of such aggregates fall within the range
necessary to ensure low optical scatter yet sufficient ink solvent
uptake.
[0031] Any fumed metallic oxide particles may be used in the
invention. Examples of such particles include fumed alumina,
silica, titania, cationic silica, antimony(III) oxide,
chromium(III) oxide, iron(III) oxide, germanium(IV) oxide,
vanadium(V) oxide, or tungsten(VI) oxide. Preferred examples of
fumed metallic oxides which may be used in the invention include
silica and alumina fumed oxides. Fumed oxides are available in dry
form or as dispersions of the aggregates mentioned above.
[0032] The image-receiving layer may also contain a mordant.
Examples of mordants which may be used include water-soluble
cationic polymers, metal salts, water-insoluble cationic polymeric
particles in the form of a latex, water dispersible polymer, beads,
or core/shell particles wherein the core is organic or inorganic
and the shell in either case is a cationic polymer. Such particles
can be products of addition or condensation polymerization, or a
combination of both. They can be linear, branched, hyper-branched,
grafted, random, blocked, or can have other polymer microstructures
well known to those in the art. They also can be partially
crosslinked.
[0033] For the porous image-receiving layer comprising particles,
the void volume must be sufficient to absorb all of the printing
ink. For example, if a porous layer has 60 volume % open pores, in
order to instantly absorb 32 cc/m.sup.2 of ink, it must have a
physical thickness of at least about 54 .mu.m.
[0034] In order to improve the adhesion of the ink-receiving layer
to the support, the surface of the support may be subjected to a
corona-discharge treatment prior to applying the image-receiving
layer.
[0035] Coating compositions employed in the invention may be
applied by any number of well known techniques, including
dip-coating, wound-wire rod coating, doctor blade coating, gravure
and reverse-roll coating, slide coating, bead coating, extrusion
coating, curtain coating and the like. Known coating and drying
methods are described in further detail in Research Disclosure no.
308119, published Dec. 1989, pages 1007 to 1008. Slide coating is
preferred, in which the base layers and overcoat may be
simultaneously applied. After coating, the layers are generally
dried by simple evaporation, which may be accelerated by known
techniques such as convection heating.
[0036] To improve colorant fade, UV absorbers, radical quenchers or
antioxidants may also be added to the image-receiving layer as is
well known in the art. Other additives include pH modifiers,
adhesion promoters, rheology modifiers, surfactants, biocides,
lubricants, dyes, optical brighteners, matte agents, antistatic
agents, etc. In order to obtain adequate coatability, additives
known to those familiar with such art such as surfactants,
defoamers, alcohol and the like may be used. A common level for
coating aids is 0.01 to 0.30% active coating aid based on the total
solution weight. These coating aids can be nonionic, anionic,
cationic or amphoteric. Specific examples are described in
MCCUTCHEON's Volume 1: Emulsifiers and Detergents, 1995, North
American Edition.
[0037] The coating composition can be coated either from water or
organic solvents, however water is preferred. The total solids
content should be selected to yield a useful coating thickness in
the most economical way, and for particulate coating formulations,
solids contents from 10-40% are typical.
[0038] Pigment Milling and Ink Formulation
[0039] The process of preparing inks from pigments commonly
involves two steps: (a) a dispersing or milling step to break up
the pigment to the primary particle, and (b) dilution step in which
the dispersed pigment concentrate is diluted with a carrier and
other addenda to a working strength ink. In the milling step, the
pigment is usually suspended in a carrier (typically the same
carrier as that in the finished ink) along with rigid, inert
milling media. Mechanical energy is supplied to this pigment
dispersion, and the collisions between the milling media and the
pigment cause the pigment to deaggregate into its primary
particles. A dispersant or stabilizer, or both, is commonly added
to the pigment dispersion to facilitate the deaggregation of the
raw pigment, to maintain colloidal particle stability, and to
retard particle reagglomeration and settling.
[0040] There are many different types of materials which may be
used as milling media, such as glasses, ceramics, metals, and
plastics. In a preferred embodiment, the grinding media can
comprise particles, preferably substantially spherical in shape,
e.g., beads, consisting essentially of a polymeric resin. In
general, polymeric resins suitable for use as milling media are
chemically and physically inert, substantially free of metals,
solvent and monomers, and of sufficient hardness and firability to
enable them to avoid being chipped or crushed during milling.
Suitable polymeric resins include crosslinked polystyrenes, such as
polystyrene crosslinked with divinylbenzene, styrene copolymers,
polyacrylates such as poly(methyl methylacrylate), olycarbonates,
polyacetals, such as Derlin.TM., vinyl chloride polymers and
copolymers, polyurethanes, polyamides, poly(tetrafluoroethylenes),
e.g., Teflon.TM., and other fluoropolymers, high density
polyethylenes, polypropylenes, cellulose ethers and esters such as
cellulose acetate, poly(hydroxyethylmethacrylate),
poly(hydroxyethylacrylate), silicone containing polymers such as
polysiloxanes and the like. The polymer can be biodegradable.
Exemplary biodegradable polymers include poly(lactides),
poly(glycolids) copolymers of lactides and glycolide,
polyanhydrides, poly(imino carbonates), poly(N-acylhydroxyproline)
esters, poly(N-palmitoyl hydroxyprolino) esters, ethylene-vinyl
acetate copolymers, poly(orthoesters), poly(caprolactones), and
poly(phosphazenes). The polymeric resin can have a density from 0.9
to 3.0 g/cm3. Higher density resins are preferred inasmuch as it is
believed that these provide more efficient particle size reduction.
Most preferred are crosslinked or uncrosslinked polymeric media
based on styrene.
[0041] Milling can take place in any suitable grinding mill.
Suitable mills include an air jet mill, a roller mill, a ball mill,
an attritor mill and a bead mill. A high speed mill is preferred.
By high speed mill we mean milling devices capable of accelerating
milling media to velocities greater than about 5 meters per second.
Sufficient milling media velocity is achieved, for example, in
Cowles-type saw tooth impeller having a diameter of 40 mm when
operated at 9,000 rpm. The preferred proportions of the milling
media, the pigment, the liquid dispersion medium and dispersant can
vary within wide limits and depends, for example, up on the
particular material selected and the size and density of the
milling media etc. After milling is complete, the dispersion of
active material is separated from the grinding media by simple
sieving or filtration. With either of the above modes the preferred
amounts and ratios of the ingredients of the mill grind will vary
widely depending upon the specific materials and the intended
applications. The contents of the milling mixture comprise the mill
grind and the milling media. The mill grind comprises pigment,
dispersant and a liquid carrier such as water. For aqueous ink jet
inks, the pigment is usually present in the mill grind at 1 to 50
weight %, excluding the milling media. The weight ratio of pigment
to dispersant is 20:1 to 1:2. The high speed mill is a high
agitation device, such as those manufactured by Morehouse-Cowles,
Hockmeyer et al.
[0042] The dispersant is another important ingredient in the mill
grind. Preferred dispersants used in the present invention include
sodium dodecyl sulfate, acrylic and styrene-acrylic copolymers,
such as those disclosed in U.S. Pat. Nos. 5,085,698 and 5,172,133,
and sulfonated polyesters and styrenics, such as those disclosed in
U.S. Pat.No. 4,597,794. Other patents referred to above in
connection with pigment availability also disclose a wide variety
of dispersant to select from. The dispersant used in the examples
is potassium N-methyl-N-oleoyl taurate (K-OMT).
[0043] The milling time can vary widely and depends upon the
pigment, mechanical means and residence conditions selected, the
initial and desired final particle size, etc. For aqueous mill
grinds using the preferred pigments, dispersants, and milling media
described above, milling times will typically range from 1 to 100
hours. The milled pigment concentrate is preferably separated from
the milling media by filtration.
[0044] The pigment particles useful in the invention may have any
particle sizes which can be jetted through a print head.
Preferably, the pigment particles have a mean particle size of less
than about 0.5 micron, more preferably less than about 0.2
micron.
[0045] A wide variety of organic and inorganic pigments, alone or
in combination, may be selected for use in the present invention.
Colorant particles which may be used in the invention include
pigments as disclosed, for example in U.S. Pat. Nos. 5,026,427;
5,086,698; 5,141,556; 5,160,370; and 5,169,436, the disclosures of
which are hereby incorporated by reference. The exact choice of
pigments will depend upon the specific application and performance
requirements such as color reproduction and image stability.
Pigments suitable for use in the present invention include, for
example, azo pigments, monoazo pigments, disazo pigments, azo
pigment lakes, .beta.-Naphthol pigments, Naphthol AS pigments,
benzimidazolone pigments, disazo condensation pigments, metal
complex pigments, isoindolinone and isoindoline pigments,
polycyclic pigments, phthalocyanine pigments, quinacridone
pigments, perylene and perinone pigments, thioindigo pigments,
anthrapyrimidone pigments, flavanthrone pigments, anthanthrone
pigments, dioxazine pigments, triarylcarbonium pigments,
quinophthalone pigments, diketopyrrolo pyrrole pigments, titanium
oxide, iron oxide, and carbon black. Typical examples of pigments
which may be used include Color Index (C.I.) Pigment Yellow 1, 2,
3, 5, 6, 10, 12, 13, 14, 16, 17, 62, 65, 73, 74, 75, 81, 83, 87,
90, 93, 94, 95, 97, 98, 99, 100, 101, 104, 106, 108, 109, 110, 111,
113, 114, 116, 117, 120, 121, 123, 124, 126, 127, 128, 129, 130,
133, 136, 138, 139, 147, 148, 150, 151, 152, 153, 154, 155, 165,
166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179,
180, 181, 182, 183, 184, 185, 187, 188, 190, 191, 192, 193, 194;
C.I. Pigment Orange 1, 2, 5, 6, 13, 15, 16, 17, 17:1, 19, 22, 24,
31, 34, 36, 38, 40, 43, 44, 46, 48, 49, 51, 59, 60, 61, 62, 64, 65,
66, 67, 68, 69; C.I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 21, 22, 23, 31, 32, 38, 48:1, 48:2,
48:3, 48:4, 49:1, 49:2, 49:3, 50:1, 51, 52:1, 52:2, 53:1, 57:1,
60:1, 63:1, 66, 67, 68, 81, 95, 112, 114, 119, 122, 136, 144, 146,
147, 148, 149, 150, 151, 164, 166, 168, 169, 170, 171, 172, 175,
176, 177, 178, 179, 181, 184, 185, 187, 188, 190, 192, 194, 200,
202, 204, 206, 207, 210, 211, 212, 213, 214, 216, 220, 222, 237,
238, 239, 240, 242, 243, 245, 247, 248, 251, 252, 253, 254, 255,
256, 258, 261, 264; C.I. Pigment Violet 1, 2, 3, 5:1, 13, 19, 23,
25, 27, 29, 31, 32, 37, 39, 42, 44, 50; C.I. Pigment Blue 1, 2, 9,
10, 14, 15:1, 15:2, 15:3, 15:4, 15:6, 15, 16, 18, 19, 24:1, 25, 56,
60, 61, 62, 63, 64, 66; C.I. Pigment Green 1, 2, 4, 7, 8, 10, 36,
45; C.I. Pigment Black 1, 7, 20, 31, 32, and C.I. Pigment Brown 1,
5, 22, 23, 25, 38, 41, 42. In a preferred embodiment of the
invention, the pigment is C.I. Pigment Blue 15:3, C.I. Pigment Red
122, C.I. Pigment Yellow 155, C.I. Pigment Yellow 74, C.I. Pigment
Black 7 or bis(phthalocyanylalumino)tetraphenyldisiloxane as
described in U.S. Pat. No. 4,311,775, the contents of which are
incorporated herein by reference.
[0046] The pigment used in element of the invention is present in
the ink jet ink in any effective amount, generally from about 0.1
to about 10% by weight, and preferably from about 0.5% to about 6%
by weight.
[0047] Typically, the aqueous carrier for the ink composition is
water or a mixture of water and at least one water miscible
co-solvent. Selection of a suitable mixture depends on requirements
of the specific application, such as desired surface tension and
viscosity, the selected pigment or dye, drying time of the ink jet
ink, and the type of paper onto which the ink will be printed.
Representative examples of water-miscible co-solvents that may be
selected include (1) alcohols, such as methyl alcohol, ethyl
alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol,
sec-butyl alcohol, t-butyl alcohol, iso-butyl alcohol, furfuryl
alcohol, and tetrahydrofurfuryl alcohol; (2) ketones or
ketoalcohols such as acetone, methyl ethyl ketone and diacetone
alcohol; (3) ethers, such as tetrahydrofuran and dioxane; (4)
esters, such as ethyl acetate, ethyl lactate, ethylene carbonate
and propylene carbonate; (5) polyhydric alcohols, such as ethylene
glycol, diethylene glycol, triethylene glycol, tetraethylene
glycol, propylene glycol, polyethylene glycol, glycerol,
2-methyl-2,4-pentanediol 1,2,6-hexanetriol and thioglycol; (6)
lower alkyl mono- or di-ethers derived from alkylene glycols, such
as ethylene glycol mono-methyl (or -ethyl) ether, diethylene glycol
mono-methyl (or -ethyl) ether, diethylene glycol mono-butyl (or
-ethyl) ether, propylene glycol mono-methyl (or -ethyl) ether,
poly(ethylene glycol) butyl ether, triethylene glycol mono-methyl
(or -ethyl) ether and diethylene glycol di-methyl (or -ethyl)
ether; (7) nitrogen containing cyclic compounds, such as
pyrrolidone, N-methyl-2-pyrrolidone, and
1,3-dimethyl-2-imidazolidinone; and (8) sulfur-containing compounds
such as dimethyl sulfoxide, 2,2'-thiodiethanol, and tetramethylene
sulfone.
[0048] Typically, the amount of aqueous carrier employed is in the
range of approximately 70 to 98 weight %, preferably approximately
90 to 98 weight %, based on the total weight of the ink. A mixture
of water and a polyhydric alcohol, such as diethylene glycol, is
useful as an aqueous carrier. In a preferred embodiment, the inks
contain from about 5 to about 60 weight % of water miscible organic
solvent. Percentages are based on the total weight of the aqueous
carrier.
[0049] Other additives which may optionally be present in the ink
jet ink compositions include thickeners, conductivity enhancing
agents, anti-kogation agents, drying agents, waterfast agents, dye
solubilizers, chelating agents, binders, light stabilizers,
viscosifiers, buffering agents, anti-mold agents, anti-curl agents,
stabilizers and defoamers. Additionally, the ink compositions can
include a humectant, a surfactant, a penetrant, a biocide, etc. as
is required depending on the application.
[0050] A humectant is usually employed in the ink jet compositions
of the invention to help prevent the ink from drying out or
crusting in the orifices of the printhead. Examples of humectants
which can be used include polyhydric alcohols, such as ethylene
glycol, diethylene glycol(DEG), triethylene glycol, propylene
glycol, tetraethylene glycol, polyethylene glycol, glycerol,
2-methyl-2,4-pentanediol,
2-ethyl-2-hydroxymethyl-1,3-propanediol(EHMP), 1,5 pentanediol,
1,2-hexanediol, 1,2,6-hexanetriol and thioglycol, lower alkyl mono-
or di-ethers derived from alkylene glycols, such as ethylene glycol
mono-methyl or mono-ethyl ether, diethylene glycol mono-methyl or
mono-ethyl ether, propylene glycol mono-methyl or mono-ethyl ether,
triethylene glycol mono-methyl, mono-ethyl or mono-butyl ether
(TEGMBE), diethylene glycol di-methyl or di-ethyl ether,
poly(ethylene glycol) monobutyl ether (PEGMBE), and diethylene
glycol monobutylether(DEGMBE); nitrogen-containing compounds, such
as urea, 2-pyrrolidinone, N-methyl-2-pyrrolidinone, and
1,3-dimethyl-2-imididazolidinone; and sulfur-containing compounds
such as dimethyl sulfoxide and tetramethylene sulfone, etc.
[0051] Preferred humectants for the inks of the invention include
DEG, glycerol, DEGMBE, TEGMBE, 1,2-hexanediol, 1,5-pentanediol,
urea, 2-pyrrolidinone, EHMP and mixtures thereof. The humectant may
be employed in each ink in an amount of from about 5 to about 60
weight percent.
[0052] Surfactants may be added to the ink to adjust the surface
tension to an appropriate level. The surfactants may be anionic,
cationic, amphoteric or nonionic and used at levels of 0.01 to 1%
of the ink composition. Preferred surfactants include Surfynol.RTM.
465 (available from Air Products Corp.) and Tergitol.RTM. 15-S-5
(available from Union Carbide).
[0053] A penetrant (0-10% by weight) may also be added to the ink
composition employed in the process of the invention to help the
ink penetrate the receiving substrate, especially when the
substrate is a highly sized paper. Examples of such penetrants
include alcohols, such as methyl alcohol, ethyl alcohol, n-propyl
alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol,
t-butyl alcohol, iso-butyl alcohol, furfuryl alcohol, and
tetrahydrofurfuryl alcohol; ketones or ketoalcohols such as
acetone, methyl ethyl ketone and diacetone alcohol; ethers, such as
tetrahydrofuran and dioxane; and esters, such as, ethyl lactate,
ethylene carbonate and propylene carbonate.
[0054] A biocide may be added to the ink composition employed in
the invention to suppress the growth of microorganisms such as
molds, fungi, etc. in aqueous inks. A preferred biocide for the ink
composition employed in the present invention is Proxel.RTM. GXL
(Avecia Corp.) at a final concentration of 0.0001-0.5 wt. %.
[0055] The pH of the aqueous ink compositions employed in the
invention may be adjusted by the addition of organic or inorganic
acids or bases. Useful inks may have a preferred pH of from about 2
to 10, depending upon the type of dye being used. Typical inorganic
acids include hydrochloric, phosphoric and sulfuric acids. Typical
organic acids include methanesulfonic, acetic and lactic acids.
Typical inorganic bases include alkali metal hydroxides and
carbonates. Typical organic bases include ammonia, triethanolamine
(TEA) and tetramethylethlenediamine.
[0056] A film-forming polymeric resin may be added to the ink
composition, to improve the wet and dry rub resistance of the
printed images. Preferably, the film forming polymeric resin is
water dispersible. The polymers used in the element of this
invention are generally hydrophobic polymers of any composition
that can be stabilized in a water-based medium. Such hydrophobic
polymers are generally classified as either condensation polymer or
addition polymers. Condensation polymers include, for example,
polyesters, polyamides, polyurethanes, polyureas, polyethers,
polycarbonates, polyacid anhydrides, and polymers comprising
combinations of the above-mentioned types. Addition polymers are
polymers formed from polymerization of vinyl-type monomers
including, for example, allyl compounds, vinyl ethers, vinyl
heterocyclic compounds, styrenes, olefins and halogenated olefins,
ethylenically unsaturated carboxylic acids and esters derived from
them, unsaturated nitriles, vinyl alcohols, acrylamides and
methacrylamides, vinyl ketones, multifunctional monomers, or
copolymers formed from various combinations of these monomers.
[0057] Preferred film-forming polymeric resin includes those
styrene/acrylic polymers prepared by free-radical polymerization of
vinyl monomers in aqueous emulsion, polyester ionomers such as
Eastman AQ.RTM. polyesters, (Eastman Chemical Company) including
Eastman Polyesters AQ 29, AQ 38, and AQ 55, and polyurethanes, such
as those disclosed in U.S. patent application, Ser. No. 09/548,514,
filed Apr. 13, 2000, of Yacobucci et al., the disclosure of which
is hereby incorporated by reference, Witcobond.RTM. polyurethane
dispersion by Witco Corp. and Sancure.RTM. polyurethane by B F
Goodrich Company.
[0058] The water dispersible film-forming polymeric resin used in
the ink set of the invention is present in the composition in any
effective amount, generally from about 0.1 to about 10% by weight,
and preferably from about 0.5% to about 5% by weight.
[0059] The ink can further comprise non film-forming particles,
including polymer particles and inorganic particles such as silica,
alumina, titanium dioxide, clay, calcium carbonate, barium sulfate,
or zinc oxide. It is preferred that the polymer particles have a
glass transition temperature greater than 60.degree. C. More
preferably, the polymer should have a glass transition temperature
greater than 80.degree. C.
[0060] The non-film forming particles used in the ink set of the
invention is present in the composition in any effective amount,
generally from about 0.1 to about 10% by weight, and preferably
from about 0.5% to about 5% by weight. The mean particles size of
the non-film forming particles used in the invention is generally
in the range of 0.01 to 1 .mu.m, more preferably 0.03 to 0.5
.mu.m.
[0061] Although the recording elements disclosed herein have been
referred to primarily as being useful for ink jet printers, they
also can be used as recording media for pen plotter assemblies. Pen
plotters operate by writing directly on the surface of a recording
medium using a pen consisting of a bundle of capillary tubes in
contact with an ink reservoir.
[0062] The following example is provided to illustrate the
invention.
EXAMPLES
[0063] Preparation of Pigment Dispersion
[0064] Cyan Pigment Dispersion
[0065] The cyan pigment dispersion contains: 8000 g of Polymeric
beads, mean diameter of 50 .mu.m (milling media); 1600 g of Bridged
aluminum phthalocyanine pigment (Eastman Kodak); 960 g of Oleoyl
methyl taurine, (OMT) Potassium salt and 5440 g of Deionized
water.
[0066] The above components were milled in a 40 liter double walled
vessel obtained from BYK-Gardner using a high energy media mill
manufactured by Morehouse-Cowles Hochmeyer. The mill was run for
approximately 8 hours at room temperature. During the milling
process, two batches of pigment samples (15.0 g each) as PC-1 and
PC-2 were obtained such that the median pigment particle sizes are
about 30 nm and 100 nm as measured by MICROTRAC II Ultrafme
particle analyzer (UPA) manufactured by Leeds & Northrup. The
medium particle size represents that 50% of the volume in the
sample is smaller than the indicated size. The dispersion was
separated from the milling media by filtering the mill grind
through a 4-8 .mu.m KIMAX.RTM. Buchner Funnel obtained from VWR
Scientific Products. Additional 8000 g of dilution water was added
to the filtered dispersion followed by a biocide, Proxel.RTM. GXL
(Zeneca Corp.). The pigment is about 10.0% by weight of the total
final dispersion and the biocide is about 230 ppm by weight of the
total final dispersion.
[0067] Yellow Pigment Dispersion
[0068] This dispersion was prepared the same as the Cyan Pigment
Dispersion 1 except that Pigment Yellow 155 (Clariant Corp.) was
used instead of Bridged aluminum phthalocyanine pigment. The amount
of OMT Potassium salt was 25 weight % based on the pigment. During
the milling process, two batches of pigment samples (15.0 g each)
as PY-1 and PY-2 were obtained such that the median pigment
particle sizes are about 110 nm and 130 nm as measured as measured
by MICROTRAC II Ultrafine particle analyzer (UPA) manufactured by
Leeds & Northrup.
[0069] Ink-Y1
[0070] To prepare the Ink-Y1, 2.5 g of Pigment Dispersion PY-1 (10%
active), 0.05 g Surfynol.RTM. 465 (Air Products Inc.), 0.8 g
glycerol, 1.0 g triethylene glycol and 0.3 g di(propyleneglycol)
methyl ether (Dowanolg DPM), and 0.33 g of AQ55.RTM. (30.5% active)
were added together with distilled water so that the final weight
of the ink was 10.0 g. The final ink contained 2.5% Pigment Yellow
155, 0.50% Surfynol.RTM. 465, 8.0% glycerol, 10.0% triethylene
glycol, 3% di(propyleneglycol) methyl ether and 1% AQ55.RTM.). The
solution was filtered through a 3 .mu.m polytetrafluoroethylene
filter and filled into an empty Epson 660 ink jet cartridge.
[0071] Ink-Y2
[0072] Ink Y2 was prepared similar to Ink-Y1 except that pigment
dispersion PY-2 was used instead of pigment dispersion PY-1.
[0073] Ink-C1
[0074] Ink C1 was prepared similar to Ink-Y1 except that 2.2 g
bridged aluminum phthalocyanine pigment dispersion PC-1 (10%
active) was used instead of pigment dispersion PY-1. The final ink
contained 2.2% by weight of bridged aluminum phthalocyanine
pigment.
[0075] Ink-C2
[0076] Ink C2 was prepared similar to Ink-C1 except that pigment
dispersion PC-2 was used instead of pigment dispersion PC-1.
[0077] Ink-M1
[0078] Ink M1 was obtained from the dark magenta channel of Epson
2000P Color Cartridges, CAT.No.T106201. The ink was then refilled
into an Epson 660 empty cartridge.
[0079] Ink-M2
[0080] Ink M2 was obtained from Epson C80 magenta cartridges, CAT.
No.T032320. The ink was then refilled into an Epson 660 empty
cartridge.
[0081] Ink Set 1 (S-1)
[0082] Ink Set 1 is a tri-color ink set consisting of cyan, magenta
and yellow, obtained from Epson C80 cartridges, CAT.No.T032220,
T032320, T032420, respectively.
[0083] Ink Set 2 (S-2)
[0084] Ink Set 1 is a tri-color ink set consisting of dark cyan,
dark magenta and yellow inks obtained from Epson 2000P Color
Cartridges, CAT. No.T106201.
[0085] Ink Set 3(S-3)
[0086] Inks-C1, M1, and Y1 were used as a set of cyan, magenta, and
yellow, and filled into the C, M, Y Channels of an Epson 660 empty
Color cartridges, respectively.
[0087] Ink Set4(S-4)
[0088] Inks-C2, M2, and Y2 were used as a set of cyan, magenta, and
yellow, and filled into the C, M, Y Channels of an Epson 660 empty
Color cartridges, respectively.
[0089] Receiver 1 (R-1)
[0090] Receiver R-1 was Kodak Instant-Dry Photographic Glossy Media
Cat 8103137, which is a porous, glossy receiver.
[0091] Receiver 2 (R-2)
[0092] Receiver R-2 was Epson Photoglossy Paper.RTM. SP911001,
(Epson Corporation), which is a porous, glossy receiver.
[0093] Element 1 of the Invention (I-1)
[0094] Element 1 (I-1) of the invention is a combination of Ink set
3 (S-3) and Receiver 1 (R-1).
[0095] Element 2 of the Invention (I-2)
[0096] Element 2 (I-2) of the invention is a combination of Ink set
4 (S-4) and Receiver 1 (R-1)
[0097] Comparative Element 1 (Comp-1)
[0098] Comparative Element 1 (Comp-1) is a combination of Ink set 1
(S-1) and Receiver 2 (R-2).
[0099] Comparative Element 2 (Comp-2)
[0100] Comparative Element 2 (Comp-2) is a combination of Ink set 2
(S-2) and Receiver 2 (R-2).
[0101] Comparative Element 3 (Comp-3)
[0102] Comparative Element 3 (Comp-3) is a combination of Ink set 2
(S-3) and Receiver 2 (R-2).
[0103] Comparative Element 4 (Comp-4)
[0104] Comparative Element 4 (Comp-4) is a combination of Ink set 4
(S-4) and Receiver 2 (R-2).
[0105] Comparative Element 5 (Comp-5)
[0106] Comparative Element 5 (Comp-5) is a combination of Ink set 2
(S-2) and Receiver 1 (R-1).
[0107] Printing and Evaluation of RGD% and RGV%
[0108] The test images used consist of cyan, magenta, yellow, red,
green and blue single color patches of approximately 3 by 3
centimeters in size with a Dmax density (100% dot coverage). Using
an Epson 660 ink jet printer loaded with the three ink sets, the
above test images were printed onto recording elements as described
above. The test images were allowed to dry for 24 hours at ambient
temperature and humidity. Using the BYK-Gardner
micro-TRI-glossmeter, gloss level from each patch was measured at
60.degree. specular angle. Multiple measurements were carried out
using three individual patches of the same color and the average
values were used. Under the same condition, gloss levels from the
non-images areas were also measured. RGD% and RGV% values were
calculated based on the above data using Equation A and Equation B.
The results are shown in Table 1.
[0109] Image Quality Evaluation
[0110] Using Ink Set 1, Ink Set 2, Ink Set 3 and Ink Set 4, full
color photographic images that contains sufficient amount of
"non-imaged" or "white" were also printed onto the recording
elements as described above. The test images were allowed to dry
for 24 hours at ambient temperature and humidity. The test images
were then subjected for the Image Quality Evaluation test. Four
neutral observers were chosen to view the same images independently
under normal office light. Using a ranking scale of 1 to 5, the
observers rated the qualities of the images based on gloss
differences, especially in the locations between imaged and the
non-images area as well as those between colors. The 1 to 5 ranking
is based on the following definition: 1: strongly noticeable
difference in gloss, 2: somewhat noticeable difference in gloss, 3:
tolerable difference in gloss, 4: slightly noticeable difference in
gloss, 5: no noticeable difference in gloss. The evaluation results
are shown in Table 2.
1 TABLE 1 Receiver/ 60 degree gloss on color patches RG RGV Element
InkSet Bk C M Y R G B D % % Comp-1 R-2/S-1 34 62 66 106 73 73 64 53
15 Comp-2 R-2/S-2 34 65 85 96 78 50 46 53 23 Comp-3 R-2/S-3 34 82
81 93 84 92 76 61 6 Comp-4 R-2/S-4 34 62 66 73 70 70 69 51 5 Comp-5
R-1/S-2 65 63 69 73 48 44 34 25 24 I-1 R-1/S-3 65 70 72 66 59 71 65
6 6 I-2 R-1/S-4 65 52 64 54 55 63 59 14 7 S = ink set R = ink
receiver Bk: Non-imaged areas, C: Cyan patch, M: Magenta patches,
Y: Yellow patch, R: Red patch, G: Green patch and B: Blue patch
[0111]
2TABLE 2 Receiver/ Observer bserve Observer Observer Aver- Element
InkSet A r B C D age Comp-1 R-2/S-1 1 1 1 1 1.0 Comp-2 R-2/S-2 1 2
1 1 1.2 Comp-3 R-2/S-3 1 1 2 1 1.2 Comp-4 R-2/S-4 1 2 2 2 1.7
Comp-5 R-1/S-2 2 3 2 3 2.5 I-1 R-1/S-3 5 5 5 5 5.0 I-2 R-1/S-4 4 3
4 4 3.8
[0112] The above results show that when the gloss level of the
porous ink jet recording elements employed in this invention are
matched with the gloss levels of the pigment based ink sets,
together with matched gloss levels among inks, the printed images
have much smaller Relative Gloss Difference (RGD%) values and
Relative Gloss Variability (RGV%) values combined as compared to
that from the comparative examples. In addition Furthermore, RGD%
and RGV% numbers as defined in this invention are consistent with
results obtained from image quality evaluation based on human
observations.
[0113] The present description will be directed in particular to
elements forming part of, or cooperating more directly with,
apparatus and methods in accordance with the present invention. It
is to be understood that elements not specifically shown or
described may take various forms well known to those skilled in the
art.
* * * * *