U.S. patent application number 13/013869 was filed with the patent office on 2011-07-28 for printed matter, method for recording color images, color printed matter, look-up table for use in color image recording, and white ink.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Takayoshi Kagata, Ippei OKUDA, Tsuyoshi Sano.
Application Number | 20110181646 13/013869 |
Document ID | / |
Family ID | 44308646 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110181646 |
Kind Code |
A1 |
OKUDA; Ippei ; et
al. |
July 28, 2011 |
PRINTED MATTER, METHOD FOR RECORDING COLOR IMAGES, COLOR PRINTED
MATTER, LOOK-UP TABLE FOR USE IN COLOR IMAGE RECORDING, AND WHITE
INK
Abstract
Printed matter, in which an image is recorded on a clear film
with a white ink containing a white coloring material and at least
one urethane resin as a resin fixative and having a degree of white
shielding of 50 or more.
Inventors: |
OKUDA; Ippei; (Shiojiri-shi,
JP) ; Kagata; Takayoshi; (Shiojirl-shi, JP) ;
Sano; Tsuyoshi; (Shiojiri-shi, JP) |
Assignee: |
SEIKO EPSON CORPORATION
|
Family ID: |
44308646 |
Appl. No.: |
13/013869 |
Filed: |
January 26, 2011 |
Current U.S.
Class: |
347/14 ;
358/3.23; 428/195.1; 524/589 |
Current CPC
Class: |
B41J 2/2114 20130101;
Y10T 428/24802 20150115; C09D 11/037 20130101; B41J 2/21 20130101;
C09D 11/322 20130101 |
Class at
Publication: |
347/14 ;
428/195.1; 524/589; 358/3.23 |
International
Class: |
B41J 29/38 20060101
B41J029/38; B32B 3/10 20060101 B32B003/10; C09D 11/10 20060101
C09D011/10; G06K 15/02 20060101 G06K015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2010 |
JP |
2010-015701 |
Claims
1. Printed matter, in which an image is recorded on a clear film
with a white ink containing a white coloring material and at least
one urethane resin as a resin fixative and having a degree of white
shielding of 50 or more.
2. Printed matter, in which an image is recorded on a clear film
with a white ink containing a white coloring material and a
combination of at least one urethane resin and a resin other than
urethane resin as a resin fixative and having a degree of white
shielding of 50 or more.
3. The printed matter according to claim 2, wherein the resin other
than urethane resin includes an acrylic styrene resin.
4. The printed matter according to claim 2, wherein the resin other
than urethane resin includes a polyethylene resin.
5. The printed matter according to claim 1, wherein the degree of
white shielding is 70 or more.
6. The printed matter according to claim 1, wherein the degree of
white shielding is expressed by "(L* value-65)/integrated
transmittance.times.1000", wherein the integrated transmittance is
the integral of transmittance at a wavelength in the range of 380
to 700 nm.
7. A recording method, comprising recording a color image with a
color ink on the image of the printed matter according to claim 1,
wherein the color image is recorded with reference to a look-up
table that corresponds to a predetermined degree of white shielding
or a predetermined white ink.
8. A recording method, comprising recording a color image with a
color ink on the image of the printed matter according to claim 2,
wherein the color image is recorded with reference to a look-up
table that corresponds to a predetermined degree of white shielding
or a predetermined white ink.
9. A recording method, comprising recording a color image with a
color ink on the image of the printed matter according to claim 3,
wherein the color image is recorded with reference to a look-up
table that corresponds to a predetermined degree of white shielding
or a predetermined white ink.
10. A recording method, comprising recording a color image with a
color ink on the image of the printed matter according to claim 4,
wherein the color image is recorded with reference to a look-up
table that corresponds to a predetermined degree of white shielding
or a predetermined white ink.
11. A recording method, comprising recording a color image with a
color ink on the image of the printed matter according to claim 5,
wherein the color image is recorded with reference to a look-up
table that corresponds to a predetermined degree of white shielding
or a predetermined white ink.
12. A recording method, comprising recording a color image with a
color ink on the image of the printed matter according to claim 6,
wherein the color image is recorded with reference to a look-up
table that corresponds to a predetermined degree of white shielding
or a predetermined white ink.
13. A look-up table for use in the recording of a color image with
a color ink on the image of the printed matter according to claim
7.
14. A look-up table for use in the recording of a color image with
a color ink on the image of the printed matter according to claim
8.
15. A look-up table for use in the recording of a color image with
a color ink on the image of the printed matter according to claim
9.
16. A look-up table for use in the recording of a color image with
a color ink on the image of the printed matter according to claim
10.
17. A look-up table for use in the recording of a color image with
a color ink on the image of the printed matter according to claim
11.
18. A look-up table for use in the recording of a color image with
a color ink on the image of the printed matter according to claim
12.
19. A white ink, comprising a white coloring material and a
combination of at least one urethane resin and a resin other than
urethane resin as a resin fixative, wherein the degree of white
shielding in recording of an image on a clear film with the white
ink is 50 or more.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention relates to white printed matter having
a wide color reproduction area, particularly white printed matter
having a wide color reproduction area when color printing is
performed on white printed matter prepared using a white ink on a
transparent substrate (for example, a clear film), for example,
made of plastic, a method for recording color images, color printed
matter, a look-up table for use in color image recording, and a
white ink.
[0003] 2. Related Art
[0004] Ink jet recording methods can record high-resolution images
with relatively simple apparatuses and are being rapidly developed
in various fields. The ink jet recording methods are used in
various applications and employ particular recording media and inks
suitable for each application.
[0005] White printed matter prepared using a white ink is generally
assessed with an indicator L-value (the luminance of reflected
light).
[0006] White coloring materials (pigments), such as titanium oxide,
are used to improve visibility. However, dotted portions of color
images have a thick ink layer, which retards the curing of the ink
layer by active energy beam irradiation through the white layer.
The resulting incomplete curing of the color ink layer can cause
color bleeding.
[0007] Regarding white ink, there is known an ink jet recording
method that can exhibit excellent visibility and tone
reproducibility even with transparent recording media or
low-brightness recording media. (see JP-A-2003-182061)
[0008] JP-A-2003-182061 includes the following description.
[0009] In the case that an image is viewed on a recording medium, a
white image is formed on the recording medium with an ink jet
printer having tone reproduction means using a white ink, and a
gray-scaled color normal image is then formed on the white image
with color inks.
[0010] In the case that an image is viewed through a recording
medium, a gray-scaled color reverse image is formed on the
recording medium with color inks, and a white image is then formed
on the reverse image with a white ink.
[0011] In such a case, in order to achieve excellent color
developability and gray scalability of color images, the white ink
layer preferably has a transmission density of 0.15 or more and an
L-value of 65 or more.
[0012] More preferably, the white ink layer has a transmission
density of 0.2 or more and an L-value of 70 or more. The white ink
layer having a transmission density and an L-value smaller than
these lower limits or the absence of the white ink layer results in
poor visibility with a low contrast between the recording medium
and the color image, particularly an unsatisfactory gray scale in a
low-density area, causing image degradation. Although the
transmission density and the L-value do not have particular upper
limits, the transmission density is 0.5 or less and the L-value is
100 or less from an ink manufacturing standpoint.
[0013] As described above, judging from the transmission density of
0.15 or more and an L-value of 65 or more, more preferably a
transmission density of 0.2 or more and an L-value of 70 or more,
JP-A-2003-182061 specifies both a high transmission density and a
high L-value to achieve excellent color developability and gray
scalability of color images.
[0014] Although white printed matter is generally assessed with an
indicator L* value (the luminance of reflected light), the
shielding capability (the degree of shielding) of white printed
matter often varies even when the L-value remains constant. The
present inventors found that this variation results from a
difference in the type and amount of resin used in the white ink
(Japanese Patent Application No. 2009-161350).
[0015] On the basis of the fact that the shielding capability of
white printed matter often varies even when the L* value remains
constant, this finding provides a new method for determining "the
degree of white shielding". The degree of white shielding is a new
definition of whiteness of white printed matter and is expressed by
an interrelated equation of the "L* value" and the "integrated
transmittance in a visible light region":
(L*value-.alpha.)/integrated transmittance.times.1000 (hereinafter
referred to as a lightness shielding (LS) value).
[0016] An example regarding white printed matter based on the new
method for determining the degree of white shielding will be
described below as a reference embodiment.
[0017] The reference embodiment is implemented as described
below.
[0018] A method for determining the degree of white shielding
according to the reference embodiment includes the steps of
measuring the L* value of white printed matter, measuring the
integrated transmittance of the white printed matter in a visible
light region, and determining the degree of white shielding from
the L* value and the integrated transmittance. Thus, the method can
determine the degree of white shielding of white printed
matter.
[0019] In the reference embodiment, the degree of white shielding
is rated on a six-point scale of AA, A, B, C, D, and E on the basis
of the visibility of light from a fluorescent lamp through printed
matter printed on a transparent medium with a white ink.
[0020] A method for manufacturing a white ink in the reference
embodiment will be described below.
[0021] The method includes the steps of determining the type of
coloring material, determining a target degree of white shielding,
and determining the type of resin fixative in accordance with the
target degree of white shielding with reference to a table stored
in advance defining the relationship between a resin fixative for
the coloring material and the degree of white shielding.
[0022] An apparatus for supporting the manufacture of a white ink
in the reference embodiment will be described below. The apparatus
includes a unit for inputting the type of coloring material to be
used, a unit for setting a target degree of white shielding, a
table defining the relationship between the type of resin fixative
and the degree of white shielding, and a unit for determining the
type of resin fixative in accordance with the target degree of
white shielding with reference to the table.
1. White Ink Composition
1.1 Coloring Material
[0023] Preferably, a white ink composition according to the
reference embodiment contains a metallic compound or hollow resin
particles as an example of white coloring material.
[0024] The metallic compound in the reference embodiment may be any
compound containing a metal atom that can be used as pigment.
Preferably, the metallic compound is a known white pigment, such as
metal oxide, barium sulfate, or calcium carbonate. Examples of the
metal oxide include, but are not limited to, titanium dioxide, zinc
oxide, silica, alumina, and magnesium oxide. Among these, titanium
dioxide and alumina are preferred as the metallic compounds in the
reference embodiment.
[0025] The amount of the metallic compound preferably ranges from
1.0% to 20.0% by mass, more preferably 5.0% to 10.0% by mass, of
the total mass of the white ink composition. The amount of the
metallic compound above 20.0% by mass may result in low
reliability, for example, because of clogging of an ink jet
recording head. The amount of the metallic compound below 1.0% by
mass tends to result in an insufficiency of color density, such as
the degree of whiteness.
[0026] The average particle size (outer diameter) of the metallic
compound preferably ranges from 30 to 600 nm, more preferably 200
to 400 nm. The outer diameter larger than 600 nm may result in low
dispersion stability, for example, because of the sedimentation of
particles or low reliability, for example, because of clogging of
an ink jet recording head. The outer diameter smaller than 30 nm
tends to result in an insufficiency of color density, such as the
degree of whiteness.
[0027] The average particle size of the metallic compound can be
measured with a particle size distribution analyzer designed on the
principle of laser diffraction scattering. The laser diffraction
particle size distribution analyzer may be a particle size
distribution analyzer designed on the principle of dynamic light
scattering (for example, "Microtrac UPA" manufactured by Nikkiso
Co., Ltd.),
[0028] Preferably, the hollow resin particles in the reference
embodiment have a cavity within a shell made of a liquid-permeable
resin. Thus, the cavity of hollow resin particles in an aqueous ink
composition is filled with an aqueous medium. The particles filled
with the aqueous medium have substantially the same specific
gravity as the aqueous medium on the outside. The hollow resin
particles can therefore be stably dispersed in the aqueous ink
composition without causing sedimentation. This can improve the
storage stability and the ejection stability of the white ink
composition.
[0029] When a white ink composition containing hollow resin
particles is ejected onto a recording medium, such as paper, an
aqueous medium within the particles evaporates during a drying
process, leaving a cavity. In the particles containing air within,
the resin layer and the air layer have different refractive indices
and effectively scatter incident light. Thus, the particles assume
white. The hollow resin particles may have a colored transparent
resin layer and assume a color other than white.
[0030] The hollow resin particles used in the reference embodiment
are not particularly limited and may be known hollow resin
particles. For example, hollow resin particles described in U.S.
Pat. Nos. 4,880,465 and 3,562,754 can preferably be used.
[0031] The average particle size (outer diameter) of the hollow
resin particles preferably ranges from 0.2 to 1.0 .mu.m, more
preferably 0.4 to 0.8 .mu.m. The outer diameter larger than 1.0
.mu.m may result in low dispersion stability, for example, because
of the sedimentation of particles or low reliability, for example,
because of clogging of an ink jet recording head. The outer
diameter smaller than 0.2 .mu.m tends to result in an insufficiency
of color density, such as the degree of whiteness. The inner
diameter of the hollow resin particles preferably ranges from
approximately 0.1 to 0.8 .mu.m.
[0032] The average particle size of the hollow resin particles can
be measured with a particle size distribution analyzer designed on
the principle of laser diffraction scattering. The laser
diffraction particle size distribution analyzer may be a particle
size distribution analyzer designed on the principle of dynamic
light scattering (for example, "Microtrac UPA" manufactured by
Nikkiso Co., Ltd.).
[0033] The amount (solid content) of the hollow resin particles
preferably ranges from 5% to 20% by mass, more preferably 8% to 15%
by mass, of the total mass of the white ink composition. The amount
(solid content) of the hollow resin particles above 20% by mass may
result in low reliability, for example, because of clogging of an
ink Net recording head. The amount (solid content) of the hollow
resin particles below 5% by mass tends to result in an
insufficiency of color density such as the degree of whiteness.
[0034] A method for preparing the hollow resin particles is not
particularly limited and may be a known method. For example, a
method for preparing the hollow resin particles is an emulsion
polymerization method in which a vinyl monomer, a surfactant, a
polymerization initiator, and an aqueous dispersion medium are
heated while stirring in a nitrogen atmosphere to form hollow resin
particle emulsion.
[0035] Examples of the vinyl monomer include nonionic
monoethylenically unsaturated monomer, such as styrene,
vinyltoluene, ethylene, vinyl acetate, vinyl chloride, vinylidene
chloride, acrylonitrile, (meth)acrylamide, and (math)acrylate.
Examples of (meth)acrylate include methyl acrylate, methyl
methacrylate, ethyl(meth)acrylate, butyl(meth)acrylate,
2-hydroxyethyl methacrylate, 2-ethylhexyl(meth)acrylate,
benzyl(meth)acrylate, laurel(meth)acrylate, oleyl(meth)acrylate,
palmityl(meth)acrylate, and stearyl(math)acrylate.
[0036] The vinyl monomer may be a bifunctional vinyl monomer.
Examples of the bifunctional vinyl monomer include divinylbenzene,
allyl methacrylate, ethylene glycol dimethacrylate, 1,3-butane-diol
dimethacrylate, and diethylene glycol dimethacrylate. The
monofuctional vinyl monomer and the bifunctional vinyl monomer can
be copolymerized to produce highly cross-linked hollow resin
particles having not only light scattering characteristics but also
heat resistance, solvent resistance, and solvent
dispersibility.
[0037] The surfactant may be any surfactant that can form a
molecular assembly, such as micelle, in water, for example, an
anionic surfactant, a nonionic surfactant, a cationic surfactant,
or an amphoteric surfactant.
[0038] The polymerization initiator may be a known compound soluble
in water, for example, hydrogen peroxide or potassium
persulfate.
[0039] The aqueous dispersion medium may be water or water
containing a hydrophilic organic solvent
1.2 Resin Fixative
[0040] Preferably, the white ink composition according to the
reference embodiment contains a resin fixative for fixing the
coloring material.
[0041] The resin fixative may be any transparent resin, for
example, acrylic styrene resin, polyurethane resin, acrylic resin,
styrene resin, polyethylene resin, or wax. Among these, in order to
achieve a higher degree of white shielding, polyurethane resin,
particularly carbonate- or ether-based aliphatic urethane resin, is
preferred.
[0042] The polyurethane resin in the reference embodiment may be of
an emulsion type in which the polyurethane resin is dispersed as
particulates in a solvent or a solution type in which the
polyurethane resin is dissolved in a solvent. The emulsion type can
be classified into a forced emulsification type and a
self-emulsification type in accordance with the emulsification
method. Although the invention can employ either of the types, the
self-emulsification type is preferred. This is because dispersion
of the self-emulsification type is superior in film-forming
properties and water resistance to the forced emulsification
type.
[0043] The average particle size of the polyurethane resin of the
emulsion type preferably ranges from 50 to 200 nm, more preferably
60 to 200 nm. The average particle size of the polyurethane resin
within this range can result in uniform dispersion of polyurethane
resin particles in the white ink composition.
[0044] The amount (solid content) of the polyurethane resin
preferably ranges from 0.5% to 10% by weight, more preferably 0.5%
to 5% by weight, of the total weight of the ink composition. The
amount of the polyurethane resin above 10% by weight may result in
poor ink reliability (such as clogging or low ejection stability),
thus failing to achieve physical properties (such as viscosity)
suitable for ink. The amount of the polyurethane resin below 0.5%
by weight results in poor fixing of ink on a recording medium, thus
failing to form images having high abrasion resistance.
1.3 Penetrating Organic Solvent
[0045] Preferably, the white ink composition according to the
reference embodiment contains at least one selected from
alkanediols and glycol ethers. Alkanediols and glycol ethers can
improve the wettability of ink to the recording surface of
recording media and the penetration ability of ink.
[0046] Preferred examples of alkanediols include 1,2-alkanediols
having four to eight carbon atoms, such as 1,2-butanediol,
1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, and
1,2-octanediol. Among these, 1,2-hexanediol, 1,2-heptanediol, and
1,2-octanediol, which have six to eight carbon atoms, are more
preferred because of their particularly high ability to penetrate
recording media.
[0047] Examples of glycol ethers include lower alkyl ethers of
polyhydric alcohols, such as ethylene glycol monomethyl ether,
ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,
diethylene glycol monomethyl ether, diethylene glycol monoethyl
ether, diethylene glycol monobutyl ether, dipropylene glycol
monomethyl ether, dipropylene glycol monoethyl ether, triethylene
glycol monomethyl ether, triethylene glycol monobutyl ether, and
tripropylene glycol monomethyl ether. Among these, use of
triethylene glycol monobutyl ether can achieve excellent recording
quality.
[0048] The amount of at least one selected from these alkanediols
and glycol ethers preferably ranges from 1% to 20% by mass, more
preferably 1% to 10% by mass, of the total mass of the white ink
composition.
1.4 Surfactant
[0049] Preferably, the white ink composition according to the
reference embodiment contains an acetylene glycol surfactant or a
polysiloxane surfactant. The acetylene glycol surfactant or the
polysiloxane surfactant can improve the wettability of ink to the
recording surface of recording media and the penetration ability of
ink.
[0050] Examples of the acetylene glycol surfactant include
2,4,7,9-tetramethyl-5-decyne-4,7-diol,
3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyne-3-ol, and
2,4-dimethyl-5-hexyne-3-ol. The acetylene glycol surfactant may
also be a commercial product, for example, Olfin E1010, STG, or Y
(manufactured by Nissin Chemical Industry Co., Ltd.), or Surfynol
104, 82, 455, 485, or TG (manufactured by Air Products and
Chemicals Inc.).
[0051] The polysiloxane surfactant may be a commercial product, for
example, BYK-347 or BYK-348 (manufactured by BYK Japan KK).
[0052] The white ink composition according to the reference
embodiment may contain another surfactant, such as an anionic
surfactant, a nonionic surfactant, or an amphoteric surfactant.
[0053] The amount of the surfactant preferably ranges from 0.01% to
5% by mass, more preferably 0.1% to 0.5% by mass, of the total mass
of the white ink composition.
1.5 Polyhydric Alcohol
[0054] Preferably, the white ink composition according to the
reference embodiment contains a polyhydric alcohol. When a white
ink composition according to an embodiment of the invention is used
in an ink jet recording apparatus, a polyhydric alcohol can retard
the drying of the ink and can prevent clogging of an ink, jet
recording head.
[0055] Examples of the polyhydric alcohol include ethylene glycol,
diethylene glycol, triethylene glycol, poly(ethylene glycol),
polypropylene glycol), propylene glycol, butylene glycol,
1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin,
trimethylolethane, and trimethylolpropane.
[0056] The amount of the polyhydric alcohol preferably ranges from
0.1% to 30% by mass, more preferably 0.5% to 20% by mass, of the
total mass of the white ink composition.
1.6 Tertiary Amine
[0057] Preferably, the white ink composition according to the
reference embodiment contains a tertiary amine. The tertiary amine
functions as a pH adjusting agent and can easily adjust the pH of
the white ink composition.
[0058] The tertiary amine may be triethanolamine. The amount of the
tertiary amine preferably ranges from 0.01% to 10% by mass, more
preferably 0.1% to 2% by mass, of the total mass of the white ink
composition.
1.7 Solvent and Additive Agent
[0059] The white ink composition according to the reference
embodiment generally contains water as a solvent. Preferably, the
water is pure water or ultrapure water, such as ion-exchanged
water, ultrafiltered water, reverse osmosis water, or distilled
water. In particular, water sterilized, for example, by ultraviolet
irradiation or the addition of hydrogen peroxide is preferred
because the sterilized water is free from mold or bacteria for a
long period of time.
[0060] If necessary, the white ink composition according to the
reference embodiment may contain an additive agent, for example, a
fixative, such as water-soluble rosin, a fungicide or preservative,
such as sodium benzoate, an antioxidant or ultraviolet absorber,
such as allophanate, a chelating agent, or an oxygen absorbent.
These additive agents may be used alone or in combination.
1.8 Preparation Method
[0061] The white ink composition according to the reference
embodiment can be prepared in the same manner as known pigment inks
with a known apparatus, such as a ball mill, a sand mill, an
attritor, a basket mill, or a rolling mill. Preferably, coarse
particles are removed with a membrane filter or a mesh filter.
[0062] The white ink composition according to the reference
embodiment can be applied to various recording media to form white
images. Examples of the recording media include paper, thick paper,
textile products, sheets and films, plastics, glass, and
ceramics.
[0063] The white ink composition according to the reference
embodiment may be used in any application, including various ink
jet recording methods. Examples of the ink jet recording methods
include thermal ink jet, piezoelectric ink jet, continuous ink jet,
roller application, and spray application.
[0064] Basic operations of a method for determining the degree of
white shielding of white printed matter according to the reference
embodiment will be described below with reference to a flow chart
illustrated in FIG. 1.
[0065] Step S1: Measure the L* value of white printed matter
printed with a white ink.
[0066] Step S2: Determine the integrated transmittance of the white
printed matter in a visible light region.
[0067] Step S3: Determine the degree of white shielding from the L*
value and the integrated transmittance determined in the steps S1
and S2.
[0068] The L* value was measured with a commercial colorimeter,
such as GretagMacbeth Spectroscan and Spectrolino (manufactured by
X-Rite Inc.), on the black backing material.
[0069] In white printing, a violet chamber of a special cartridge
of an ink jet printer ("PX-G930" manufactured by Seiko Epson Co.)
was filled with the white ink composition. A printing test was
performed with the printer on which the ink cartridge was
mounted.
[0070] The white ink composition was applied to Lumirror S10-100
.mu.m (manufactured by Toray Industries, Inc.) in 1440.times.720
dpi resolution.
[0071] In the reference embodiment, the term "duty" is defined by
the following equation.
Duty (%) Number of dots printed/(Vertical
resolution.times.Horizontal resolution).times.100
[0072] wherein the "number of dots printed" refers to the number of
dots printed per unit area, and the "vertical resolution" and the
"horizontal resolution" refer to resolution per unit area 100% duty
means the maximum ink mass of a single color per pixel.
[0073] The integrated transmittance of a white printed matter
sample is the integrated transmittance in a visible light region
(for example, a region in the range of 380 to 700 nm). The
wavelength range is not limited to the above-mentioned range and
may be another wavelength range in the visible light region. In
that case, a correspondence between the LS value and the reference
level may be different from the correspondence in the reference
embodiment.
[0074] The integrated transmittance in the reference embodiment is
determined in the following manner.
[0075] Light passing through a white printed matter sample is
measured with a spectrophotometer in the visible light region (the
region in the range of 380 to 700 nm) at 1 nm intervals.
[0076] The measured values are outputted in the form of 0 to 100
(%).
[0077] The measured values are integrated (hereinafter referred to
as an integrated transmittance).
[0078] The integrated transmittance ranges from 0 to 32,000,
wherein 0 indicates complete shielding, and 32,000 indicates
complete transmission.
[0079] Although the spectrophotometer is used in the measurement
described above, the integrated transmittance may be determined
from reflectivity obtained by reflective measurement.
[0080] The degree of white shielding is determined from the L*
value and the integrated transmittance by the following
equation.
[0081] Degree of white shielding (LS value)=(L*
value-.alpha.)/Integrated transmittance.times.1000
[0082] The subtraction of .alpha. from the L* value aims to
accentuate the influence of a change in the L* value in the white
region. The .alpha. is a predetermined value (in the range of 60 to
70) and is preferably, but is not limited to, "65".
[0083] In the reference embodiment, the degree of white shielding
(LS value) determined in the step S3 is compared with a
predetermined value.
[0084] More specifically, the degree of white shielding is rated on
the plurality of levels (AA, A, B, D, and B) in organoleptic
evaluation relying on the visual inspection of an observer. The
degree of white shielding at each of the levels is correlated with
actual measurement.
[0085] The following are the criteria for the levels (AA, A, B, C,
D, and E).
[0086] Degree of white shielding E: Light from a fluorescent lamp
through white printed matter can be clearly seen while the white
printed matter cannot be recognized.
[0087] Degree of white shielding D: Light from a fluorescent lamp
through white printed matter can be clearly seen while the white
printed matter can also be recognized.
[0088] Degree of white shielding C: Light from a fluorescent lamp
through white printed matter is seen slightly dimly.
[0089] Degree of white shielding B: Light from a fluorescent lamp
through white printed matter is seen dimly.
[0090] Degree of white shielding A: Light from a fluorescent lamp
through white printed matter can scarcely be seen.
[0091] Degree of white shielding AA: Light from a fluorescent lamp
through white printed matter cannot be seen.
[0092] In the reference embodiment, the thresholds for the degree
of white shielding (LS value) at the levels (AA, A, B, C, D, and E)
are, but are not limited to, the following values. The levels
according to the organoleptic evaluation relying on the visual
inspection of an observer are also not limited to these six
levels.
[0093] Degree of white shielding E: Transparent medium (not white
printed matter).
[0094] Degree of white shielding D: White printed matter having an
LS value larger than 0 but smaller than 54.
[0095] Degree of white shielding C: White printed matter having an
LS value of 54 or more.
[0096] Degree of white shielding B: White printed matter having an
LS value of 64 or more.
[0097] Degree of white shielding A: White printed matter having an
LS value of 82 or more.
[0098] Degree of white shielding AA: White printed matter having an
LS value of 87 or more.
[0099] A method for manufacturing a white ink composition according
to the reference embodiment containing a coloring material and a
resin fixative will be described below.
[0100] A method for manufacturing a white ink, composition
according to the reference embodiment employs an apparatus for
supporting the manufacture of a white ink that includes a unit for
inputting the type of coloring material, a unit for setting the
degree of white shielding, a storage for storing a table defining
the relationship between the type of resin fixative for the
coloring material and the degree of white shielding, and a
processor. The method for manufacturing a white ink composition
according to the reference embodiment includes a step of
determining the type of coloring material, a step of setting a
target degree of white shielding, and a step of determining the
type of resin fixative in accordance with the target degree of
white shielding with reference to the table stored in advance
defining the relationship between the resin fixative for the
coloring material and the degree of white shielding.
[0101] Representative reference examples according to the reference
embodiment will be described below.
[0102] Table 1 in FIG. 2 shows representative examples, the degree
of white shielding (LS value) of each of which is rated level AA,
A, B, C, D, or E.
[0103] FIG. 2 shows reference examples in which titanium dioxide
and hollow resin particles are used as coloring materials (there is
a case where no coloring material is used), and all acrylic styrene
resin ("Joncryl 62J" manufactured by BASF), a urethane resin A
("D-6300" manufactured by Dainichiseika Color & Chemicals Mfg.
Co., Ltd.), a urethane resin B ("D-6455" manufactured by
Dainichiseika Color & Chemicals Mfg. Co., Ltd.), and a urethane
resin C ("D-2020" manufactured by Dainichiseika Color &
Chemicals Mfg. Co., Ltd.) are used as representative resin
fixatives (there is a case where no resin fixative is used).
[0104] For Comparative Example (Reference Example) 1 in FIG. 2
containing no coloring material and no resin fixative (a PET
recording medium alone), the L-value is not available, the
integrated transmittance is 12136 (light substantially passes
through the recording medium), the LS value is 0, and the degree of
shielding is rated E.
[0105] Comparative Example (Reference Example) 2 contains 10% by
mass of titanium dioxide as a coloring material, no resin fixative,
1% by mass of a surfactant, 2% by mass of propylene glycol, 5% by
mass of 1,2-hexanediol, 2% by mass of 2-pyrrolidone, and water as
the remainder. Comparative Example (Reference Example) 2 has an
L-value of 70.3, an integrated transmittance of 1113.9, an LS value
of 4.7, and the degree of shielding rated D. The results of
Reference Example 2 show that the white ink containing titanium
dioxide as a coloring material and no resin fixative has a much
lower degree of shielding than white inks containing a resin
fixative.
[0106] When a white ink having a high degree of white shielding is
desired, the white ink preferably contains titanium dioxide and a
resin fixative.
[0107] Reference Example 1-1 contains 10% by mass of titanium
dioxide particles as a coloring material, 4% by mass of an acrylic
styrene resin ("Joncryl 62J" manufactured by BASF) as a resin
fixative, 1% by mass of a surfactant, 2% by mass of propylene
glycol, 5% by mass of 1,2-hexanediol, 2% by mass of 2-pyrrolidone,
and water as the remainder. Reference Example 1-1 has an L-value of
76.8, an integrated transmittance of 194.3, an LS value of 60, and
the degree of shielding rated C.
[0108] Reference Example 2-1 contains 10% by mass of titanium
dioxide particles as a coloring material, 4% by mass of a urethane
resin A ("D6300" manufactured by Dainichiseika Color &
Chemicals Mfg. Co., Ltd.) as a resin fixative, 1% by mass of a
surfactant, 2% by mass of propylene glycol, 5% by mass of
1,2-hexanediol, 2% by mass of 2-pyrrolidone, and water as the
remainder. Reference Example 2-1 has an L-value of 74.8, an
integrated transmittance of 151.76, an LS value of 64, and the
degree of shielding rated B.
[0109] Reference Example 3-1 contains 10% by mass of titanium
dioxide particles as a coloring material, 4% by mass of a urethane
resin B ("D6455" manufactured by Dainichiseika Color &
Chemicals Mfg. Co., Ltd.) as a resin fixative, 1% by mass of a
surfactant, 2% by mass of propylene glycol, 5% by mass of
1,2-hexanediol, 2% by mass of 2-pyrrolidone, and water as the
remainder. Reference Example 3-1 has an L-value of 75.3, an
integrated transmittance of 119.17, an LS value of 86, and the
degree of shielding rated A.
[0110] Reference Example 4-1 contains 10% by mass of titanium
dioxide as a coloring material, 4% by mass of a urethane resin C
("D2020" manufactured by Dainichiseika Color & Chemicals Mfg.
Co., Ltd.) as a resin fixative, 1% by mass of a surfactant, 2% by
mass of propylene glycol, 5% by mass of 1,2-hexanediol, 2% by mass
of 2-pyrrolidone, and water as the remainder. Reference Example 4-1
has an L-value of 74.9, an integrated transmittance of 102.45, an
LS value of 96, and the degree of shielding rated A.
[0111] Reference Example 5 contains 10% by mass of hollow resin
particles as a coloring material, 4% by mass of a urethane resin B
("D6455" manufactured by Dainichiseika Color & Chemicals Mfg.
Co., Ltd.) as a resin fixative, 1% by mass of a surfactant, 2% by
mass of propylene glycol, 5% by mass of 1,2-hexanediol, 2% by mass
of 2-pyrrolidone, and water as the remainder, Reference Example 5
has an L-value of 78.5, an integrated transmittance of 194.5, an LS
value of 69, and the degree of shielding rated B.
[0112] The results in FIG. 2 show that the white ink compositions
containing titanium dioxide particles as a coloring material and a
urethane resin as a resin fixative generally have a high LS value
although the LS value depends on the type of urethane resin.
[0113] FIG. 2 also shows that use of hollow resin particles as a
coloring material (Reference Example 5) results in a higher L-value
but a lower LS value than use of titanium dioxide particles
(Reference Example 3-1).
[0114] FIGS. 3, 4, and 5 show other reference examples having the
same degree of shielding (rating) as some of the reference examples
in FIG. 2.
[0115] FIG. 3 (Table 2) shows other reference examples having the
same degree of shielding (rating) B as Reference Example 2-1 shown
in FIG. 2. Except that 4% by mass of W635 (Reference Example 2-2),
AQ515 (Reference Example 2-3), or W605 (Reference Example 2-4) is
used as a resin fixative, the other conditions are the same as the
conditions of Reference Example 2-1.
[0116] FIG. 4 (Table 3) shows another reference example having the
same degree of shielding (rating) A as Reference Example 3-1 shown
in FIG. 2. Except that 4% by mass of WS6021 (Reference Example 3-2)
is used as a resin fixative, the other conditions are the same as
the conditions of Reference Example 2-1.
[0117] FIG. 5 (Table 4) shows other reference examples having the
same degree of shielding (rating) AA as Reference Example 4-1 shown
in FIG. 2. Except that 4% by mass of D4200 (Reference Example 4-2)
or WS5000 (Reference Example 4-3) used as a resin fixative, the
other conditions are the same as the conditions of Reference
Example 2-1.
[0118] In the reference examples, as shown in FIG. 2, titanium
dioxide and hollow resin particles are used as coloring materials
(there is a case where no coloring material is used), and the
acrylic styrene resin ("Joncryl 62J" manufactured by BASF), the
urethane resin A ("D-6300" manufactured by Dainichiseika Color
& Chemicals Mfg. Co., Ltd.), the urethane resin B ("D-6455"
manufactured by Dainichiseika Color & Chemicals Mfg. Co.,
Ltd.), and the urethane resin C ("D-2020" manufactured by
Dainichiseika Color & Chemicals Mfg. Co., Ltd.) are used as
representative resin fixatives (there is a case where no resin
fixative is used). Each of the reference examples employs only one
type of resin (basically urethane resin) as the resin fixative.
Thus, the LS value and the applicability of white ink compositions
containing a plurality of resins as resin fixatives have not been
examined.
SUMMARY
[0119] An advantage of some aspects of the invention is that it
provides the determination of the LS value of a white ink
containing titanium dioxide or hollow resin particles as a coloring
material and a combination of at least one urethane resin and
another resin as a resin fixative and, as utilization based on the
LS value, provides printed matter having a wide color reproduction
area.
[0120] Another advantage of some aspects of the invention is that
it provides a method for recording color images Using printed
matter and provides color printed matter, a look-up table for use
in color image recording, and a white ink for use in printed
matter.
[0121] In printed matter according to an aspect of the invention,
an image is recorded on a clear film with a white ink containing a
white coloring material and at least one urethane resin as a resin
fixative and having a degree of white shielding of 50 or more.
[0122] In printed matter according to an aspect of the invention,
an image is recorded on a clear film with a white ink containing a
white coloring material and a combination of at least one urethane
resin and a resin other than urethane resin as a resin fixative and
having a degree of white shielding of 50 or more.
[0123] The resin other than urethane resin may include an acrylic
styrene resin.
[0124] The resin other than urethane resin may include a
polyethylene resin.
[0125] The degree of white shielding may be 70 or more.
[0126] The degree of white shielding may be expressed by
"(L*value-65)/integrated transmittance.times.1000".
[0127] The integrated transmittance is the integral of
transmittance at a wavelength in the range of 380 to 700 nm.
[0128] A recording method, including recording a color image with a
color ink on the image of the printed matter described above,
wherein the color image is recorded with reference to a look-up
table that corresponds to a predetermined, degree of white
shielding or a predetermined white ink.
[0129] A look-up table for use in the recording of a color image
with a color ink on the image of the printed matter according to
the recording method described above.
[0130] A white ink, containing a white coloring material and a
combination of at least one urethane resin and a resin other than
urethane resin as a resin fixative, wherein the degree of white
shielding in recording of an image on a clear film with the white
ink is 50 or more.
[0131] An advantage of some aspects of the invention is that it
provides the determination of the LS value of a white ink
containing a white coloring material and a combination of at least
one urethane resin and another resin as a resin fixative and, on
the basis of the LS value, provides printed matter having a wide
color reproduction area.
[0132] Another advantage of some aspects of the invention is that
it provides a method for recording color images using printed
matter and provides color printed matter, a look-up table for use
in color image recording, and a white ink for use in printed
matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0133] The invention will be described with reference to the
accompanying drawings, wherein like numbers reference like
elements.
[0134] FIG. 1 is a flow chart illustrating basic operations of a
method for determining the degree of white shielding of printed
matter according to a reference embodiment.
[0135] FIG. 2 illustrates Table 1 showing representative examples,
the degree of white shielding (LS value) of each of which is rated
level AA, A, B, C, D, or E.
[0136] FIG. 3 illustrates Table 2 showing other reference examples
having the same degree of shielding (rating) B as Reference Example
2-1 shown in FIG. 2.
[0137] FIG. 4 illustrates Table 3 showing another reference example
having the same degree of shielding (rating) A as Reference Example
3-1 shown in FIG. 2.
[0138] FIG. 5 illustrates Table 4 showing other reference examples
having the same degree of shielding (rating) AA as Reference
Example 4-1 shown in FIG. 2.
[0139] FIG. 6 illustrates Table 5 showing the gamut volumes of
Examples 1 to 4 having a degree of white shielding (LS value) of 50
or more and Comparative Examples 1 and 2 having a degree of white
shielding (LS value) of less than 50.
[0140] FIG. 7 is an explanatory drawing illustrating a gamut
difference between Example 1 having an LS value of 53 and
Comparative Example 2 having an LS value of 27.
[0141] FIG. 8 is an explanatory drawing illustrating a gamut
difference between examples having almost the same L-values (74.9
and 74.8) and different integrated transmittances (136 and
364).
[0142] FIG. 9 is an explanatory drawing illustrating a gamut
difference between examples having almost the same integrated
transmittances (136 and 132) and different L-values (74.9 and
75.7).
[0143] FIG. 10 is a table showing the LS value (the degree of white
shielding), corresponding a- and b-values, and ODs for black (K),
cyan (C), magenta (M), and yellow (Y).
DESCRIPTION OF EXEMPLARY EMBODIMENTS
Examples
[0144] As described below, measurement conditions for examples of
the invention shown in Table 5 in FIG. 6 are the same as the
measurement conditions for the reference embodiment. The L* value
was measured with a commercial colorimeter, such as GretagMacbeth
Spectroscan and Spectrolino (manufactured by X-Rite Inc.), on the
black backing material.
[0145] In white printing, a violet chamber of a special cartridge
of an ink jet printer ("PX-G930" manufactured by Seiko Epson Co.)
was filled with the white ink composition. A printing test was
performed with the printer on which the ink cartridge was
mounted.
[0146] The white ink composition was applied to Lumirror S10-100
.mu.m (manufactured by Toray Industries, Inc.) in 1440.times.720
dpi resolution.
[0147] The integrated transmittance of a white printed matter
sample is the integrated transmittance in a visible light region
(for example, a region in the range of 380 to 700 nm). The
wavelength range is not limited to the above-mentioned range and
may be another wavelength range in the visible light region. In
that case, a correspondence between the LS value and the reference
level may be different from the correspondence in the reference
embodiment.
[0148] As in the reference embodiment, the integrated transmittance
was determined by the following method.
[0149] Light passing through a white printed matter sample was
measured with a spectrophotometer in the visible light region (the
region in the range of 380 to 700 nm) at 1 nm intervals. The
measured values were outputted in the form of 0 to 100 (%).
[0150] The measured values were integrated (hereinafter referred to
as an integrated transmittance).
[0151] The integrated transmittance ranges from 0 to 32,000,
wherein 0 indicates complete shielding, and 32,000 indicates
complete transmission.
[0152] Although the spectrophotometer was used in the measurement
described above, the integrated transmittance may be determined
from reflectivity obtained by reflective measurement.
[0153] The degree of white shielding was determined from the L*
value and the integrated transmittance by the following
equation.
Degree of white shielding (LS value)=(L* value-.alpha.)/Integrated
transmittance.times.1000
[0154] The subtraction of .alpha. from the L* value aimed to
accentuate the influence of a change in the L* value in the white
region. The .alpha. is a predetermined value (in the range of 60 to
70) and was "65" in the examples.
[0155] The "Gamut volume" in Table 5 in FIG. 6 refers to the gamut
volume in the Lab three-dimensional space.
[0156] The gamut volume was measured in the following manner.
[0157] A specific output pattern composed of 400 patches was
printed on the white printed matter sample with color inks. The
colors of patches were measured over the entire printed matter to
calculate the gamut volume in the L*a*b* three-dimensional space
with an arithmetic tool. The gamut volume calculated is
dimensionless.
[0158] Representative examples (measurement examples) according to
embodiments of the invention will be described below. FIG. 6 (Table
5) shows the gamut volumes of Examples 1 to 4 having a degree of
white shielding (LS value) of 50 or more and Comparative Examples 1
and 2 having a degree of white shielding (LS value) of less than
50.
[0159] in FIG. 6, titanium dioxide was used as a coloring material
(there was a case where no coloring material was used), and a
urethane resin (resin A: "W605" manufactured by Mitsui Chemicals
Polyurethane Co., Ltd.) and resins other than urethane (resin B: an
acrylic styrene resin "Joncryl 62J" manufactured by BASF and resin
C: a polyethylene resin "S120" manufactured by Mitsui Chemicals,
Inc.) were used as resin fixatives. Furthermore, "WBR-022U"
manufactured by Taisei Fine Chemical Co., Ltd., "W635" manufactured
by Mitsui Takeda Chemicals, Inc., and "D-6300", "D-6455", and
"D-2020" manufactured by Dainichiseika Color & Chemicals Mfg.
Co., Ltd. can be used as urethane resins. Examples of the resin
other than urethane resin include acrylic styrene resins, such as
"Joncryl 511", "Joncryl 711", and "Joncryl 7001" manufactured by
BASF and polyethylene resins, such as "AQ515" manufactured by BYK
Japan KK and "Hytec E-7025P" and "Hytec E-2213" manufactured by
Toho Chemical Industry Co., Ltd.
[0160] Comparative Example 1 in Table 5 in FIG. 6 containing no
coloring material and no resin fixative (a PET recording medium
alone) had no available L-value, an integrated transmittance of
16136 (light substantially passed through the recording medium), an
LS value of 0, and a gamut volume of 560.
[0161] An ink according to Comparative Example 2 contained 10% by
mass of titanium dioxide as a coloring material, no urethane resin
A, 2% by mass of each of the resin B and the resin C as resin
fixatives other than urethane resin, 1% by mass of a surfactant, 2%
by mass of propylene glycol, 5% by mass of 1,2-hexanediol, 2% by
mass of 2-pyrrolidone, and water as the remainder.
[0162] Comparative Example 2 had an L-value of 74.8, an integrated
transmittance of 364, an LS value of 27, and a gamut volume of
378160.
[0163] An ink according to Example 1 contained 10% by mass of
titanium dioxide as a coloring material, 1% by mass of the urethane
resin A and 1% by mass of each of the resin B (acrylic styrene
resin) and the resin C (polyethylene resin) other than urethane
resin as resin fixatives, 1% by mass of a surfactant, 2% by mass of
propylene glycol, 5% by mass of 1,2-hexanediol, 2% by mass of
2-pyrrolidone, and water as the remainder.
[0164] Example 1 had an L-value of 75.9, an integrated
transmittance of 207, an LS value of 53, and a gamut volume of
400360.
[0165] An ink according to Example 2 contained 10% by mass of
titanium dioxide as a coloring material, 2% by mass of the Urethane
resin A and 2% by mass of each of the resin B and the resin C other
than urethane resin as resin fixatives, 1% by mass of a surfactant,
2% by mass of propylene glycol, 5% by mass of 1,2-hexanediol, 2% by
mass of 2-pyrrolidone, and water as the remainder.
[0166] Example 2 had an L-value of 74.9, an integrated
transmittance of 136, an LS value of 73, and a gamut volume of
421936.
[0167] An ink according to Example 3 contained 10% by mass of
titanium dioxide as a coloring material, 2% by mass of the urethane
resin A and 2% by mass of the resin B and 1% by mass of the resin C
other than urethane resin as resin fixatives, 1% by mass of a
surfactant, 2% by mass of propylene glycol, 5% by mass of
1,2-hexanediol, 2% by mass of 2-pyrrolidone, and water as the
remainder.
[0168] Example 3 had an L-value of 74.6, an integrated
transmittance of 128, an LS value of 75, and a gamut volume of
424320.
[0169] An ink according to Example 4 contained 10% by mass of
titanium dioxide as a coloring material, 2% by mass of the urethane
resin A and 4% by mass of the resin C other than urethane resin as
resin fixatives, 1% by mass of a surfactant, 2% by mass of
propylene glycol, 5% by mass of 1,2-hexanediol, 2% by mass of
2-pyrrolidone, and water as the remainder.
[0170] Example 4 had an L-value of 75.7, an integrated
transmittance of 132, an LS value of 81, and a gamut volume of
444832.
[0171] A gamut difference between Example 1 having an LS value of
53 and Comparative Example 2 having an LS value of 27 will be
described below with reference to FIG. 7.
[0172] FIG. 7 illustrates the color reproduction areas in the
ab-region partitioned at the L-values of 10, 20, 30, 40, 50, 60,
70, 80, and 90 in the Lab three-dimensional space,
[0173] FIG. 7 shows that a white ink having an LS value of 53 has a
wider color reproduction area than a white ink having an LS value
of 27.
[0174] A gamut difference between examples having almost the same
L-values (74.9 and 74.8) and different integrated transmittances
(136 and 364), that is, between Example 2 having an LS value of 73
and Comparative Example 2 having an LS value of 27 will be
described below with reference to FIG. 8.
[0175] FIG. 8 illustrates the color reproduction areas in the
ab-region partitioned at the L-values of 10, 20, 30, 40, 50, 60,
70, 80, and 90 in the Lab three-dimensional space for Example 2
having an LS value of 73 and Comparative Example 2 having an LS
value of 27.
[0176] FIG. 8 shows that a white ink having an LS value of 73 has a
wider color reproduction area than a white ink having an LS value
of 27.
[0177] A gamut difference between examples having almost the same
integrated transmittances (136 and 132) and different L-values
(74.9 and 75.7), that is, between Example 2 having an LS value of
73 and Example 4 having an LS value of 81 will be described below
with reference to FIG. 9.
[0178] FIG. 9 illustrates the color reproduction areas in the
ab-region partitioned at the L-values of 10, 20, 30, 40, 50, 60,
70, 80, and 90 in the Lab three-dimensional space for Example 2
having an LS value of 73 and Example 4 having an LS value of
81.
[0179] FIG. 9 shows that a white ink having an LS value of 81 has a
wider color reproduction area than a white ink having an LS value
of 73.
[0180] The gamut examples illustrated in FIGS. 7 to 9 show that
white printed matter recorded with a white ink having an LS value
of 50 or more has a wide color reproduction area.
[0181] Furthermore, independent of a difference between the
L-values or the integrated transmittances, white printed matter
recorded with a white ink having a large LS value has a wide color
reproduction area.
[0182] A table in FIG. 10 shows the LS value (the degree of white
shielding), corresponding a- and b-values, and ODs for black (K),
cyan (C), magenta (M), and yellow (Y) for Reference Example 2 and
Examples 1, 2, and 4.
[0183] The table in FIG. 10 shows that the ODs do not vary,
significantly even when the LS value varies between 27 and 81. As
in paragraph [0063], the ODs were measured with a commercial
colorimeter, such as GretagMacbeth Spectroscan and Spectrolino
(manufactured by X-Rite Inc.), on the black backing material.
[0184] In white printing, a violet chamber of a special cartridge
of an ink jet printer ("PX-G930" manufactured by Seiko Epson Co.)
was filled with the white ink composition. A printing test was
performed with the printer on which the ink cartridge was
mounted.
[0185] The white ink composition was applied to Lumirror S10-100
.mu.m (manufactured by Toray Industries, Inc.) in 1440.times.720
dpi resolution. Patches were then printed with each of color inks
(black (K), cyan (C), magenta (M), and yellow (Y)) on the samples
to which the white ink composition was applied. The ODs of the
patches were measured.
[0186] In printing with the color inks in the measurement of the
gamut volumes and the ODs described above, black, cyan, magenta,
and yellow ink chambers of a special cartridge mounted on an ink
jet printer ("PX-G930" manufactured by Seiko Epson Co.) were filled
with their respective color inks. Like the white ink composition
described above, the color inks used contained water as the main
solvent, their respective pigments, a resin fixative, a surfactant,
an organic solvent as a penetrant or a humectant, and optionally
another additive agent. Such a color ink composition can be found
in JP-A-2006-282822.
[0187] The examples described above show that the gamut
reproducible area in the printing of the color inks on a white
shielding layer depends on the degree of white shielding. Thus, in
the recording of color images on a white base layer having a
predetermined degree of white shielding, reference to a look-up
table that corresponds to the degree of white shielding allows the
reproduction of optimum colors for the degree of white shielding in
a wide color reproduction area. The look-up table defines
correspondences between image data, such as RBG, to be printed and
data on the amount of ink to be applied by a printer. With
reference to the look-up table, the printer obtains the data on the
amount of ink and performs printing. The data on the amount of ink
outputted from the look-up table cover the entire color
reproduction area depending on the corresponding degree of white
shielding. The data are designed such that the color image
recording is performed over the entire color reproduction area
depending on the corresponding degree of white shielding.
[0188] The examples described above also show that the degree of
white shielding varies with the white ink composition (white ink).
Thus, in the recording of color images on a white shielding layer
printed with a given white ink composition, reference to a look-up
table that corresponds to the white ink composition allows the
reproduction of optimum colors for the white ink composition in a
wide color reproduction area. The data on the amount of ink
outputted from the look-up table cover the entire color
reproduction area depending on the corresponding white ink. The
data are designed such that the color image recording is performed
over the entire color reproduction area depending on the
corresponding white ink. Thus, even when the same image data are
inputted to look-up tables, the look-up tables in which the
corresponding degrees of white shielding or white inks are
different can output different data on the amount of ink.
* * * * *