U.S. patent application number 15/232118 was filed with the patent office on 2016-12-01 for ink, ink cartridge, and inkjet recording apparatus.
This patent application is currently assigned to RICOH COMPANY, LTD.. The applicant listed for this patent is Hisashi Habashi, Tomohiro Inoue, Masayuki Koyano, Takashi OKADA. Invention is credited to Hisashi Habashi, Tomohiro Inoue, Masayuki Koyano, Takashi OKADA.
Application Number | 20160347962 15/232118 |
Document ID | / |
Family ID | 53481014 |
Filed Date | 2016-12-01 |
United States Patent
Application |
20160347962 |
Kind Code |
A1 |
OKADA; Takashi ; et
al. |
December 1, 2016 |
INK, INK CARTRIDGE, AND INKJET RECORDING APPARATUS
Abstract
Provided is an ink containing at least: an inorganic pigment
having a surface hydrophobicity; resin particles; and water.
Inventors: |
OKADA; Takashi; (Kanagawa,
JP) ; Inoue; Tomohiro; (Kanagawa, JP) ;
Habashi; Hisashi; (Kanagawa, JP) ; Koyano;
Masayuki; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OKADA; Takashi
Inoue; Tomohiro
Habashi; Hisashi
Koyano; Masayuki |
Kanagawa
Kanagawa
Kanagawa
Kanagawa |
|
JP
JP
JP
JP |
|
|
Assignee: |
RICOH COMPANY, LTD.
Tokyo
JP
|
Family ID: |
53481014 |
Appl. No.: |
15/232118 |
Filed: |
August 9, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14571506 |
Dec 16, 2014 |
|
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15232118 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08K 9/04 20130101; C08K
9/02 20130101; C09D 11/107 20130101; C09D 11/322 20130101; C01P
2004/62 20130101; Y10T 428/24901 20150115; B41J 2/17503 20130101;
C09D 11/36 20130101; C08K 9/06 20130101; C09C 1/30 20130101; C09D
11/102 20130101; B41J 2/2114 20130101; B41M 5/50 20130101; C01P
2006/22 20130101; C09C 1/3653 20130101; C09C 1/3684 20130101; C09C
1/3669 20130101 |
International
Class: |
C09D 11/322 20060101
C09D011/322; B41J 2/175 20060101 B41J002/175; C09D 11/107 20060101
C09D011/107; C09D 11/102 20060101 C09D011/102; B41M 5/50 20060101
B41M005/50; C09D 11/36 20060101 C09D011/36 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 2013 |
JP |
2013-268914 |
Claims
1-13. (canceled)
14. An ink, comprising: an inorganic pigment having a surface
hydrophobicity; resin particles; water; and a water-soluble organic
solvent, wherein the water-soluble organic solvent is at least one
of 3-methyl-1,3-butanediol and 3-methoxy-3-methyl-1-butanol, and
wherein the inorganic pigment having the surface hydrophobicity is
dispersed in the water with the water-soluble organic solvent, and
a chemical structure for imparting hydrophobicity to a surface of
the inorganic pigment is selected from a group consisting of alkyl
and fluoroalkyl.
15. The ink according to claim 14, wherein the inorganic pigment
having a surface hydrophobicity is titanium dioxide.
16. The ink according to claim 14, wherein a silane coupling agent
selected from a group consisting of dialkyl dihalogenated silane,
trialkyl halogenated silane, and alkyl trihalogenated silane is
utilized in imparting hydrophobicity to the surface of the
inorganic pigment.
17. The ink according to claim 14, wherein a particle diameter
(D50) of the inorganic pigment having a surface hydrophobicity at a
50% cumulative mean in a volume-basis particle size distribution
thereof is from 200 nm to 600 nm.
18. The ink according to claim 14, wherein the resin particles are
at least one kind selected from the group consisting of styrene
acrylic resin particles, acrylic silicone resin particles,
polyurethane resin particles, and acrylic urethane resin
particles.
19. The ink according to claim 14, wherein a content of the resin
particles is from 0.1% by mass to 20% by mass.
20. The ink according to claim 14, wherein the ink is a white
ink.
21. The ink according to claim 14, wherein the ink is for inkjet
recording.
22. An inkjet recording method, comprising: applying an impulsion
to the ink according claim 14 to fly the ink, to thereby record an
image on a recording medium.
23. An image forming method, comprising: forming an image over a
base material using the ink according to claim 14.
24. An ink recorded matter, comprising: an image formed over a base
material using the ink according to claim 14.
25. An ink cartridge, comprising: an ink; and a container in which
the ink is contained, wherein the ink comprises: an inorganic
pigment having a surface hydrophobicity; resin particles; water;
and a water-soluble organic solvent, wherein the water-soluble
organic solvent is at least one of 3-methyl-1,3-butanediol and
3-methoxy-3-methyl-1-butanol, and wherein the inorganic pigment
having the surface hydrophobicity is dispersed in the water with
the water-soluble organic solvent, and a chemical structure for
imparting hydrophobicity to a surface of the inorganic pigment is
selected from a group consisting of alkyl and fluoroalkyl.
26. An inkjet recording apparatus, comprising: an ink flying unit
configured to apply an impulsion to an ink to fly the ink, to
thereby record an image on a recording medium, wherein the ink
comprises: an inorganic pigment having a surface hydrophobicity;
resin particles; water; and a water-soluble organic solvent,
wherein the water-soluble organic solvent is at least one of
3-methyl-1,3-butanediol and 3-methoxy-3-methyl-1-butanol, and
wherein the inorganic pigment having the surface hydrophobicity is
dispersed in the water with the water-soluble organic solvent, and
a chemical structure for imparting hydrophobicity to a surface of
the inorganic pigment is selected from a group consisting of alkyl
and fluoroalkyl.
Description
BACKGROUND OF THE INVENTION
[0001] Field of the Invention
[0002] The present invention relates to an ink, an ink cartridge,
and an inkjet recording apparatus.
[0003] Description of the Related Art
[0004] Most ordinary inkjet recording inks are highly transparent
inks intended for being printed on white recording media. When such
inks are printed on a transparent base material or a base material
having a low luminosity, a visible print is difficult to obtain
because a contrast or a clear color development performance may not
be obtained. Hence, attempts are being made to use white inks
having a high hiding power.
[0005] As such white inks, inks containing a white inorganic
pigment as a colorant are used. Because such inorganic pigments
generally have a specific gravity greater than that of organic
pigments, their problem is susceptibility to colorant settling. For
example, ink cartridges housing an ink containing a commercially
available inorganic pigment as a colorant (containing titanium
dioxide surface-treated for hydrophilization) have a warning that
the ink cartridges must be shaken before use, when 10 days or more
has passed since the last service (see
http://dLepson.jp/support/manual/data/ink/pxw8000/4118542_00.
PDF).
[0006] Further, it has been necessary to use inkjet recording
apparatuses including a stirring mechanism or a circulation
mechanism, when using inks containing an inorganic pigment such as
titanium dioxide as a colorant (see Japanese Patent Application
Laid-Open (JP-A) No. 2010-222385).
[0007] Further, JP-A No. 2013-208760 describes use of hydrophobized
titanium dioxide as an aqueous dispersion. However, titanium
dioxide is not used as a colorant; titanium dioxide particles
suppress agglutination with an electrolytic effect.
[0008] Further, there is proposed an aqueous pigment dispersion
liquid that contains: titanium oxide surface-treated with alumina
and silica and then further surface-treated with a silane coupling
agent; a resin having an anionic group; a water-soluble organic
solvent; and a basic compound (see JP-A-No. 2011-225867). However,
the resin having an anionic group in this proposal is a
water-soluble polymer (a water-soluble styrene acrylic-based resin
is used in an Example), and not present in the ink in the form of
resin particles, leading to a problem that a settling property and
re-dispersibility are poor.
[0009] Hence, it is requested to provide an ink in which an
inorganic pigment contained as a colorant hardly settles, and can
easily redisperse even if it settles.
SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide an ink in
which an inorganic pigment contained as a colorant hardly settles,
and can easily redisperse even if it settles.
[0011] An ink of the present invention as a solution to the problem
described above contains at least:
[0012] an inorganic pigment having a surface hydrophobicity;
[0013] resin particles; and
[0014] water.
[0015] The present invention can solve the conventional problems
described above, achieve the object described above, and provide an
ink in which an inorganic pigment contained as a colorant hardly
settles, and can easily redisperse even if it settles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic diagram showing an example of an ink
cartridge.
[0017] FIG. 2 is a schematic diagram of the ink cartridge of FIG.
1, including the case thereof.
[0018] FIG. 3 is a perspective diagram showing an example of an
inkjet recording apparatus.
[0019] FIG. 4 is a schematic diagram showing another example of an
inkjet recording apparatus.
[0020] FIG. 5 is a schematic plan view of a main portion, showing
an example of a mechanical portion of an inkjet recording
apparatus.
[0021] FIG. 6 is a schematic plan view showing an example of a
mechanical portion of an inkjet recording apparatus, where A
represents a carriage main-scanning direction, and B represents a
belt conveying direction (sub-scanning direction).
DETAILED DESCRIPTION OF THE INVENTION
(Ink)
[0022] An ink of the present invention contains at least an
inorganic pigment having a surface hydrophobicity, resin particles,
and water, preferably contains a water-soluble organic solvent, and
further contains other components according to necessity.
[0023] According to the present invention, in an ink containing
water, a water-soluble organic solvent, a dispersant, and an
inorganic pigment, hydrophobization of the inorganic pigment and
addition of resin particles make it harder for the inorganic
pigment having the surface hydrophobicity to settle and to easily
redisperse even if it settles.
<Inorganic Pigment Having Surface Hydrophobicity>
[0024] "Surface hydrophobicity" of the inorganic pigment having a
surface hydrophobicity is defined as follows. Pure water (10 g) and
the inorganic pigment (2 g) are added in a 30 mL sample bottle
(SV-30 manufactured by Nichidenrika-Glass Co., Ltd.) in which a
stirring bar is put, stirred and mixed at 400 rpm for 10 minutes
with a stirrer (MS-2T manufactured by Ishii Laboratory Works Co.,
Ltd.), and then kept stationary for 30 minutes. In this case, when
the inorganic pigment is wholly floating without having settled, it
is judged to have a "surface hydrophobicity". When the inorganic
pigment has settled even partially, it is judged to have no
"surface hydrophobicity".
[0025] Examples of inorganic pigments as the inorganic pigment
having a surface hydrophobicity include titanium dioxide, silicon
dioxide, zinc dioxide, and barium sulfate. One of these may be used
alone, or two or more of these may be used in combination. Among
these, titanium dioxide is preferable.
[0026] The inorganic pigment is not particularly limited, and may
be an inorganic pigment that is not surface-treated, or may be an
inorganic pigment that is surface-treated in order for wettability
with a treating agent for hydrophobization to be increased and
thereby hydrophobization efficiency to be improved. Examples of
surface treatment include oxides of aluminum silicon, zirconium,
and zinc.
[0027] Examples of chemical structures for imparting hydrophobicity
to the surface of the inorganic pigment include alkyl, alkyl
silane, fluoroalkyl, and silicone oil. Among these, silicone
treatment and alkyl treatment are preferable.
[0028] The inorganic pigment having a surface hydrophobicity may be
an appropriately produced product or may be a commercially
available product.
[0029] As a method for the production, the inorganic pigment having
a surface hydrophobicity may be produced by bringing a
publicly-known silane coupling agent such as dialkyl dihalogenated
silane, trialkyl halogenated silane, and alkyl trihalogenated
silane or a silicone oil such as dimethyl silicone oil, and an
inorganic pigment into a contact reaction at a high
temperature.
[0030] Examples of the commercially available product include
TiO.sub.2 surface-treated with hydrophobic silicone (CR-63
manufactured by Ishihara Sangyo Kaisha, Ltd.), and TiO.sub.2
surface-treated with hydrophobic silicone (MTY-02 manufactured by
Tayca Corporation).
[0031] A particle diameter (D50) of the inorganic pigment having a
surface hydrophobicity at a 50% cumulative mean in a volume-basis
particle size distribution thereof is preferably from 200 nm to 600
nm, and more preferably from 250 nm to 500 nm. When the particle
diameter is in the average secondary particle diameter range
described above, it is possible to ensure a printed image a hiding
power, and at the same time to suppress clogging of an ink path in
an inkjet apparatus and a discharge nozzle and work the apparatus
stably.
[0032] The particle diameter (D50) at the 50% cumulative mean may
be measured with, for example, a granularity distribution analyzer
(MICROTRACK UPA-EX150 manufactured by Nikkiso Co., Ltd.).
[0033] The content of the inorganic pigment having a surface
hydrophobicity is preferably from 1% by mass to 20% by mass, and
more preferably from 3% by mass to 15% by mass, relative to the
whole amount of the ink,
<Dispersant>
[0034] The inorganic pigment having a surface hydrophobicity may be
dispersed in water with a water-soluble organic solvent, a
dispersant, or the like, and prepared as a pigment dispersion
liquid.
[0035] The water-soluble organic solvent to be used will be
described later.
[0036] Examples of the dispersant for dispersing the inorganic
pigment having a surface hydrophobicity in a dispersion liquid
include a water-soluble resin and a surfactant.
[0037] The method for dispersing may be a general-purpose equipment
such as ultrasonic irradiation, a homogenizer, a ball mill, a beads
mill, a paint shaker, etc.
[0038] It is possible to prepare the pigment dispersion liquid as
an ink by mixing it with a vehicle. The prepared ink can be used
favorably for inkjet recording purposes.
<<Water-Soluble Resin>>
[0039] Examples of the water-soluble resin include a block
copolymer or a random copolymer made of at least two selected from
the group consisting of styrene, a styrene derivative, a vinyl
naphthalene derivative, aliphatic alcohol ester, etc. of
.alpha.,.beta.-ethyleny unsaturated carboxylic acid, an acrylic
acid, an acrylic acid derivative, a maleic acid, a maleic acid
derivative, an itaconic acid, an itaconic acid derivative, a
fumaric acid, and a fumaric acid derivative, or a salt of the block
copolymer or the random copolymer.
[0040] These water-soluble resins are alkali-soluble resins that
are soluble in an aqueous solution in which a base is dissolved.
Among these resins, those having a weight average molecular weight
of from 3,000 to 20,000 are preferable because when used for an
ink, such resins can suppress the viscosity of the dispersion
liquid and can easily disperse.
[0041] The content of the water-soluble resin is preferably from
0.1% by mass to 10% by mass relative to the whole amount of the
ink.
<<Surfactant>>
[0042] Examples of the surfactant include an anionic surfactant, a
nonionic surfactant, an amphoteric surfactant, an acetylene
glycol-based surfactant, a fluorosurfactant, and a silicone-based
surfactant. It is preferable to select from among these, a
surfactant that does not spoil dispersion stability, depending on
the combination of the inorganic pigment having a surface
hydrophobicity and the water-soluble organic solvent.
[0043] The surfactant is not particularly limited to these, and one
of these may be used alone or more than one of these may be used as
a mixture. Even if a given surfactant does not easily dissolve in
an ink alone, it may be solubilized and present stably in an ink
when mixed with any other.
[0044] Examples of the anionic surfactant include polyoxyethylene
alkylether acetic acid salt, a dodecylbenzene sulfonic acid salt, a
succinic acid ester sulfonic acid salt, a lauric acid salt, and a
polyoxyethylene alkylether sulfate salt.
[0045] Examples of the nonionic surfactant include polyoxyethylene
alkyl ether, polyoxyethylene polyoxypropylene alkylether,
polyoxyethylene alkylester, polyoxyethylene polyoxypropylene
alkylester, polyoxyethylene sorbitan fatty acid ester,
polyoxyethylene alkylphenylether, polyoxyethylene alkylamine, and
polyoxyethylene alkylamide.
[0046] Examples of the amphoteric surfactant include a lauryl amino
propionic acid salt, lauryldimethyl betaine, stearyldimethyl
betaine, and lauryldihydroxyethyl betaine. Specific examples
include lauryldimethyl amine oxide, myristyldimethyl amine oxide,
stearyldimethyl amine oxide, dihydroxyethyl laurylamine oxide,
polyoxyethylene palm oil alkyldimethyl amine oxide, dimethylalkyl
(palm) betaine, and dimethyl lauryl betaine.
[0047] Examples of the acetylene glycol-based surfactant include
acetylene glycol-based products such as
2,4,7,9-tetramethyl-5-desine-4,7-diol,
3,6-dimethyl-4-octyne-3,6-diol, and 3,5-dimethyl-1-hexin-3-ol
(e.g., SURFYNOL 104, 82, 465, 485, and TG manufactured by Air
Products and Chemicals, Inc.).
[0048] Examples of the fluorosurfactant include a perfluoroalkyl
sulfonic acid salt, a perfluoroalkyl carboxylic acid salt, a
perfluoroalkyl phosphoric acid ester, a perfluoroalkyl ethylene
oxide adduct, perfluoroalkyl betaine, a perfluoroalkylamine oxide
compound, a polyoxyalkylene ether polymer having a perfluoroalkyl
ether group in a side chain or a sulfuric acid ester salt thereof,
and a fluoro-aliphatic polymer ester.
[0049] Examples of commercially available products of the
fluorosurfactant include: SURFLON S-111, S-112, S-113, S121, S131,
S132, S-141, and S-145 (manufactured by Asahi Glass Co., Ltd.);
FLUORAD FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430,
FC-431, and FC-4430 (manufactured by Sumitomo 3M Limited); FT-110,
250, 251, and 400S (manufactured by Neos Company Limited); ZONYL
FS-62, FSA, FSE, FSJ, FSP, TBS, UR, FSO, FSO-100, FSN N, FSN-100,
FS-300, and FSK (manufactured by Du Pont Kabushiki Kaisha); and
POLYFOX PF-136A, PF-156A, and PF-151N (manufactured by Omnova
Solutions Inc.). One of these may be used alone, or two or more of
these may be used in combination.
[0050] The silicone-based surfactant is not particularly limited,
and an arbitrary silicone-based surfactant may be selected
according to the purpose. However, a silicone-based surfactant that
does not decompose at a high pH is preferable. Examples of such
silicone-based surfactants include a side chain-modified
polydimethyl siloxane, a both terminal-modified polydimethyl
siloxane, a one terminal-modified polydimethyl siloxane, and a side
chain/both terminal-modified polydimethyl siloxane. Among these, a
polyether-modified silicone-based surfactant having a
polyoxyethylene group and a polyoxyethylene polyoxypropylene group
as modifying groups is particularly preferable.
[0051] The polyether-modified silicone-based surfactant may be a
commercially available product, examples of which include KF-618,
KF-642, and KF-643 (all manufactured by Shin-Etsu Chemical Co.,
Ltd.).
[0052] The content of the surfactant is preferably from 0.01% by
mass to 5% by mass, and more preferably from 0.5% by mass to 2% by
mass, relative to the whole amount of the ink. When the content is
less than 0.01% by mass, addition of the surfactant may be
ineffective. When the content is greater than 5% by mass, the ink
may permeate a recording medium more than necessary, which may
result in such problems as a low image density and occurrence of a
bleed-through.
<Resin Particles>
[0053] The resin particles have properties of thickening and
agglomerating upon landing of the ink on a recording medium, and
have an effect of suppressing permeation of the colorant component
and promoting fixing thereof on the recording medium. Further, some
kinds of resin particles have an effect of forming a film over a
recording medium and improving scratch resistance of the print.
Furthermore, addition of the resin particles improves dispersion
stability of the inorganic pigment having a surface hydrophobicity.
Moreover, in the present invention, the resin particles have an
effect of suppressing settling of the inorganic pigment having a
surface hydrophobicity, and improving re-dispersibility thereof
even if it settles.
[0054] Examples of the resin particles include styrene acrylic
resin particles, acrylic silicone resin particles, polyurethane
resin particles, and acrylic urethane resin particles. Among these,
polyurethane resin particles are particularly preferable.
[0055] The resin particles are present in the form of solid
particles when used as a material for ink production or after ink
production.
[0056] The polyurethane resin particles include a type that is
obtained by granulating a relatively hydrophilic polyurethane resin
by externally using an emulsifier, and a self-emulsifying type
obtained by incorporating a functional group that serves as an
emulsifier into the resin itself by means of copolymerization or
the like. The present invention may be carried out with either
type. However, care must be taken because depending on the
combination in the ink composition, there may be some difference in
the dispersion stability of the inorganic pigment having a surface
hydrophobicity and the resin particles. Resin particles that always
have excellent dispersion stability without fail in any combination
of the inorganic pigment having a surface hydrophobicity and the
dispersant are anionic self-emulsifying polyurethane resin
particles. In this case, the polyurethane-based resin is more
preferably an ether type than a polyester type and a polycarbonate
type, in terms of fastness and dispersion stability of the
inorganic pigment having a surface hydrophobicity. Many non-ether
types have a poor solvent resistance and tend to viscously
agglomerate during storage of the ink at a high temperature,
although the reasons are uncertain.
[0057] The resin particles may be a commercially available product.
Examples of commercially available products include: J-450, J-734,
J-7600, J-352, J-390, J-7100, J-741, J74J, J-511, J-840, J-775,
HRC-1645, and HPD-71 (styrene-acrylic resin particles, all
manufactured by Johnson Polymer, LLC); UVA383MA (acrylic-silicone
resin particles, manufactured by BASF Japan Ltd.); AP4710
(acrylic-silicone resin particles, manufactured by Showa
Highpolymer Co., Ltd.); SF460, SF460S, SF420, SF110, SF300, and
SF361 (polyurethane resin particles, all manufactured by NUC
Corporation); and ACRIT WEM-321U (acrylic urethane resin particles,
manufactured by Taisei Kako Co., Ltd.). One of these may be used
alone, or two or more of these may be used in combination.
[0058] The content of the resin particles is preferably from 0.1%
by mass to 20% by mass, and more preferably from 0.2% by mass to
10% by mass, relative to the whole amount of the ink. When the
content is less than 0.1% by mass, dispersibility and
re-dispersibility of the inorganic pigment having a surface
hydrophobicity may be poor, and an amount of the resin to cover the
inorganic pigment having a surface hydrophobicity after the ink
lands on a recording medium may be insufficient, resulting in a
poor effect of scratch resistance. When the content is greater than
20% by mass, the ink may have an excessively high viscosity and may
be difficult to print by an inkjet system.
<Water-Soluble Organic Solvent>
[0059] In the present invention, by mixing a water-soluble organic
solvent with water as a dispersion medium and controlling the
hydrophilicity of the dispersion medium, it is possible not only to
disperse the inorganic pigment having a surface hydrophobicity
uniformly, but also to make the inorganic pigment having a surface
hydrophobicity less susceptible to settling in the dispersion
liquid and make it easily re-disperse even if it settles.
[0060] The water-soluble organic solvent is not particularly
limited, and an arbitrary water-soluble organic solvent may be
selected according to the purpose. Examples thereof include
multivalent alcohols, multivalent alcohol alkyl ethers, multivalent
alcohol aryl ethers, nitrogen-containing heterocyclic compounds,
amides, amines, sulfur-containing compounds, propylene carbonate,
and ethylene carbonate.
[0061] Examples of the multivalent alcohols include ethylene
glycol, polyethylene glycol, propylene glycol, dipropylene glycol,
tripropylene glycol, polypropylene glycol, 1,5-pentanediol,
2-methyl-2,4-pentanediol, hexylene glycol, 1,6-hexanediol,
1,2,6-hexanetriol, trimethylolethane, trimethylolpropane,
3-methyl-1,3-hexanediol, propylpropylene diglycol, glycerin,
1,3-butanediol, 1,2,3-butanetriol, 1,2,4-butanetirol, diglycerin,
triethylene glycol, tetraethylene glycol, diethylene glycol,
3-methyl-1,3-butanediol, and 3-methoxy-3-methyl-1-butanol. One of
these may be used alone, or two or more of these may be used in
combination.
[0062] Examples of the multivalent alcohol alkyl ethers include
ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,
diethylene glycol monomethyl ether, diethylene glycol monoethyl
ether, diethylene glycol monobutyl ether, ethylene glycol
mono-2-ethylhexyl ether, propylene glycol monoethyl ether, and
triethylene glycol dimethyl ether. One of these may be used alone,
or two or more of these may be used in combination.
[0063] Examples of the multivalent alcohol aryl ethers include
ethylene glycol monophenyl ether, and ethylene glycol monobenzyl
ether.
[0064] Examples of cyclic ethers include epoxies, oxetanes,
tetrahydrofurans, tetrahydropyrans, and crown ether.
[0065] Examples of the amines include monoethanol amine, diethanol
amine, triethanol amine, N, N-dimethylmonoethanol amine,
N-methyldiethanol amine, N-methylethanol amine, N-phenylethanol
amine, and 3-aminopropyl diethyl amine.
[0066] Examples of the amide compounds include 2-pyrrolidone,
N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone,
.epsilon.-caprolactam, .gamma.-butyrolactone,
.beta.-methoxy-N,N-dimethyl propionamide, and
.beta.-butoxy-N,N-dimethyl propionamide.
[0067] Examples of the sulfur-containing compounds include dimethyl
sulfoxide, sulfolane, and thiodiglycol.
[0068] The content of the water-soluble organic solvent is
preferably from 10% by mass to 50% by mass, and more preferably
from 15% by mass to 40% by mass, relative to the whole amount of
the ink. When the content is less than 15% by mass, ink discharge
stability may be poor, and a non-volatile component may be deposit
and adhere to a maintenance device of an inkjet recording
apparatus. On the other hand, when the content is greater than 50%
by mass, a non-volatile component may deposit due to even a slight
desiccation, and the ink may have a poor drying property on a
recording medium and may take a long time to dry.
<Other Components>
[0069] The other components are not particularly limited, and
arbitrary components may be selected according to necessity.
Examples thereof include a permeant, a pH adjustor, an
antiseptic/mildewcide, a chelate reagent, an anticorrosive agent,
an oxygen absorber, and a photostabilizing agent.
-Permeant-
[0070] Examples of the permeant include
2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol,
2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol,
2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol,
5-hexene-1,2-diol, and 2-ethyl-1,3-hexanediol. One of these may be
used alone, or two or more of these may be used in combination.
Among these, 2-ethyl-1,3-hexanediol, and
2,2,4-trimethyl-1,3-pentanediol are preferable.
[0071] Examples of other permeants include: alkyl and aryl ethers
of multivalent alcohols, such as diethylene glycol monophenyl
ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl
ether, diethylene glycol monophenyl ether, diethylene glycol
monobutyl ether, propylene glycol monobutyl ether, and
tetraethylene glycol chlorophenyl ether; and lower alcohols such as
ethanol.
[0072] The content of the permeant is preferably from 0.1% by mass
to 4% by mass relative to the whole amount of the ink. When the
content is less than 0.1% by mass, a quick drying property may not
be obtained and an image may be smudged. When the content is
greater than 4% by mass, such problems may occur that dispersion
stability of the inorganic pigment having a surface hydrophobicity
is lost, a nozzle is clogged, and the ink has a more than necessary
permeability to a recording medium to result in a low image density
or cause a bleed-through.
-pH Adjustor-
[0073] The pH adjustor is not particularly limited, and an
arbitrary pH adjustor may be selected according to the purpose as
long as it can adjust pH to a value of from 7 to 11 without giving
adverse influence to the ink in which it is mixed. Examples thereof
include alcohol amines, hydroxides of alkali metal elements,
ammonium hydroxides, phosphonium hydroxides, and alkali metal
carbonates.
[0074] When the pH is lower than 7 or higher than 11, erosion of an
inkjet head or an ink supply unit by the ink may be large, and
troubles such as property changes, leakage, and discharge failure
of the ink may occur.
[0075] Examples of the alcohol amines include diethanol amine,
triethanol amine, and 2-amino-2-ethyl-1,3-propanediol.
[0076] Examples of the hydroxides of alkali metal elements include
lithium hydroxide, sodium hydroxide, and potassium hydroxide.
[0077] Examples of the ammonium hydroxides include ammonium
hydroxide, and quaternary ammonium hydroxide.
[0078] Examples of the phosphonium hydroxides include quaternary
phosphonium hydroxide.
[0079] Examples of the alkali metal carbonates include lithium
carbonate, sodium carbonate, and potassium carbonate.
-Antiseptic/Mildewcide-
[0080] Examples of the antiseptic/mildewcide include sodium
dehydroacetate, sodium sorbate, sodium-2-pyridinethiol-1-oxide,
sodium benzoate, and sodium pentachlorophenol.
[0081] Examples of the chelate reagent include sodium ethylene
diamine tetraacetate, sodium nitrilotriacetate, sodium hydroxyethyl
ethylene diamine triacetate, sodium diethylenetriamine
pentaacetate, and sodium uramil diacetate.
[0082] Examples of the anticorrosive agent include acidic sulfite,
sodium thiosulfate, ammonium thiodiglycolate, diisopropyl ammonium
nitrite, pentaerythritol tetranitrate, and dicyclohexyl ammonium
nitrite.
-Antioxidant-
[0083] Examples of an antioxidant include a phenol-based
antioxidant (including a hindered phenol-based antioxidant), an
amine-based antioxidant, a sulfur-based antioxidant, and a
phosphorus-based antioxidant.
[0084] Examples of the phenol-based antioxidant (including a
hindered phenol-based antioxidant) include butylated hydroxy
anisole, 2,6-di-tert-butyl-4-ethylphenol,
stearyl-.beta.-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,
2,2'-methylenebis(4-methyl-6-tert-butylphenol),
2,2'-methylenebis(4-ethyl-6-tert-butylphenol),
4,4'-butylidenebis(3-methyl-6-tert-butylphenol),
3,9-bis{1,1-dimethyl-2-[.beta.-(3-tert-butyl-4-hydroxy-5-methylphenyl)
propnionyloxy]ethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane,
1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane,
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,
and
tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]met-
hane.
[0085] Examples of the amine-based antioxidant include
phenyl-.beta.-naphthyl amine, .alpha.-naphthyl amine,
N,N'-di-sec-butyl-p-phenylenediamine, phenothiazine,
N,N'-diphenyl-p-phenylenediamine, 2,6-di-tert-butyl-p-cresol,
2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl-phenol,
butylhydroxyanisole,
2,2'-methylenebis(4-methyl-6-tert-butylphenol),
4,4'-butylidenebis(3-methyl-6-tert-butylphenol),
4,4'-thiobis(3-methyl-6-tert-butylphenol),
tetrakis[methylene-3-(3,5-di-tert-butyl-4-dihydroxyphenyl)propionate]meth-
ane, and
1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
[0086] Examples of the sulfur-based antioxidant include
dilauryl-3,3'-thiodipropionate, distearyl thiodipropionate, lauryl
stearyl thiodipropionate, dimyristyl-3,3'-thiodipropionate,
distearyl-.beta.,.beta.'-thiodipropionate,
2-mercaptobenzoimidazole, and dilauryl sulfide.
[0087] Examples of the phosphorus-based antioxidant include
triphenyl phosphite, octadecyl phosphite, triisodecyl phosphite,
trilauryl trithiophosphite, and trinonyl phenyl phosphite.
-Ultraviolet Absorber-
[0088] Examples of an ultraviolet absorber include a
benzophenone-based ultraviolet absorber, a benzotriazole-based
ultraviolet absorber, a salicylate-based ultraviolet absorber, a
cyanoacrylate-based ultraviolet absorber, and a nickel complex
salt-based ultraviolet absorber.
[0089] Examples of the benzophenone-based ultraviolet absorber
include 2-hydroxy-4-n-octoxybenzophenone,
2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone,
2-hydroxy-4-methoxybenzophenone, and
2,2',4,4'-tetrahydroxybenzophenone.
[0090] Examples of the benzotriazole-based ultraviolet absorber
include 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole,
2-(2'-hydroxy-5'-methylphenyl)benzotriazole,
2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, and
2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole.
[0091] Examples of the salicylate-based ultraviolet absorber
include phenyl salicylate, p-tert-butylphenyl salicylate, and
p-octylphenyl salicylate.
[0092] Examples of the cyanoacrylate-based ultraviolet absorber
include ethyl-2-cyano-3,3'-diphenylacrylate,
methyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate, and
butyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate.
[0093] Examples of the nickel complex salt-based ultraviolet
absorber include nickelbis(octylphenyl)sulfide,
2,2'-thiobis(4-tert-octylferrate)-n-butyl amine nickel(II),
2,2'-thiobis(4-tert-octylferrate)-2-ethylhexyl amine nickel(II),
and 2,2'-thiobis(4-tert-octylferrate)triethanol amine
nickel(II).
<Ink Production Method>
[0094] The ink is produced by dispersing or dissolving a pigment
dispersion liquid containing the inorganic pigment having a surface
hydrophobicity, the resin particles, the dispersant, the
water-soluble organic solvent, and water, and according to
necessity, any other components in an aqueous medium, and according
to necessity, stirring and mixing them. The stirring and mixing may
be performed with, for example, a sand mill, a homogenizer, a ball
mill, a paint shaker, an ultrasonic disperser, etc. The stirring
and mixing may be performed with a stirrer using an ordinary
stirring blade, a magnetic stirrer, a high-speed disperser,
etc.
<<Physical Properties of Ink>>
[0095] Physical properties of the ink are not particularly limited,
and may be appropriately selected according to the purpose. For
example, the viscosity and the surface tension of the ink are
preferably in the ranges described below.
[0096] The viscosity of the ink at 25.degree. C. is preferably from
5 mPas to 25 mPas. When the viscosity is 5 mPas or greater, an
effect of improving a print density and character appearance
quality is obtained. When the viscosity is suppressed to 25 mPas or
less, ink dischargeability is ensured.
[0097] The viscosity can be measured at 25.degree. C. with, for
example, a viscometer (RE-550L manufactured by Toki Sangyo Co.,
Ltd.).
[0098] The surface tension of the ink is preferably 30 mN/m or
less, and more preferably 28 mN/m or less at 25.degree. C. When the
surface tension is 30 mN/m or less, the ink has a good permeability
and causes less beading, which leads to a good drying property
during printing on regular paper. Further, the ink has a good
wettability with a pre-treatment layer, which leads to a good color
development property and white spot suppression. On the other hand,
when the surface tension is greater than 30 mN/m, the ink tends to
be leveled over a recording medium, and may take a long time to dry
(have a poor drying property).
[0099] The ink can be used favorably in a printer mounted with any
types of inkjet heads, such as a piezo type that uses a
piezoelectric element as a pressure generation unit for
pressurizing the ink in an ink flow path, and deforming a vibration
plate that forms the wall surface of the ink flow path to thereby
change the cubic capacity within the ink flow path and discharge
ink droplets (see JP-A No. 02-51734), a so-called thermal type that
heats the ink within an ink flow path with a heat generating
resistor and generates bubbles (see JP-A No. 61-59911), and an
electrostatic type that deforms a vibration plate that forms the
wall surface of an ink flow path with an electrostatic force
generated between the vibration plate and an electrode disposed
opposite to the vibration plate, to thereby change the cubic
capacity within the ink flow path and discharge ink droplets (see
JP-A No. 06-71882).
[0100] The ink can also be used in a printer or the like that has a
function of promoting print fixing by heating a recording medium
and the ink at from 50.degree. C. to 200.degree. C. during, before,
or after printing.
[0101] The ink of the present invention can be recorded on various
surfaces including a base material having a low luminosity such as
a black base material, and a transparent base material with a
sufficient whiteness and a high visibility. Therefore, the ink is
useful for the purposes of marking on industrial products such as
plastic products.
[0102] Further, the colorant of the ink, that is, the inorganic
pigment hardly settles, and can easily re-disperse even if it
settles. Therefore, the ink can be used for various purposes
including an inkjet recording ink and a coating material. However,
it is preferable that the ink be used as an inkjet recording ink
described below.
(Ink Cartridge)
[0103] An ink cartridge of the present invention includes the ink
of the present invention described above, and a container, and
further includes other members such as an ink bag according to
necessity. Hence, in an ink replacement operation or the like,
there is no need of directly touching the ink, there is no risk of
fingers or wears being contaminated, and mixing of foreign matters
such as dirt into the ink can be prevented.
[0104] The container is not particularly limited, and the shape,
structure, size, material, etc. thereof may be appropriately
selected according to the purpose. A preferable example of the
container is one that includes an ink bag formed of an aluminum
laminate film, a resin film, or the like.
[0105] The ink cartridge will be explained below with reference to
FIG. 1 and FIG. 2. FIG. 1 is a schematic diagram showing an example
of an ink bag 241 of the ink cartridge. FIG. 2 is a schematic
diagram showing an ink cartridge 200 that includes the ink bag 241
of FIG. 1, and a cartridge case 244 housing the ink bag.
[0106] As shown in FIG. 1, the ink bag 241 is filled with the ink
through an ink injection port 242, deaerated of any residual air
therein, and then closed at the ink injection port 242 by fusion
bonding. For use, an ink discharge port 243 formed of a rubber
material is pierced with a needle of the apparatus body for the ink
to be supplied into the apparatus. The ink bag 241 is formed of a
packaging material having no gas permeability, such as an aluminum
laminate film. Then, typically, the ink bag is housed in a
cartridge case 244 formed of a plastic as shown in FIG. 2, and as a
thusly obtained ink cartridge 200, mounted on an inkjet recording
apparatus attachably and detachably.
[0107] It is preferable that the ink cartridge be attachable to and
detachable from an inkjet recording apparatus. This makes it
possible to simplify an ink refill or replacement work and improve
the work efficiency.
(Inkjet Recording Method and Inkjet Recording Apparatus)
[0108] An inkjet recording apparatus of the present invention
includes at least an ink flying unit, and further includes other
units appropriately selected according to necessity, such as an
impulsion generation unit and a control unit.
[0109] An inkjet recording method of the present invention includes
at least an ink flying step, and further includes other steps
appropriately selected according to necessity, such as an impulsion
generating step and a control step.
[0110] The inkjet recording method of the present invention can be
performed favorably by the inkjet recording apparatus of the
present invention. The ink flying step can be performed favorably
by the ink flying unit. The other steps can be performed favorably
by the other units.
-Ink Flying Step and Ink Flying Unit-
[0111] The ink flying step is a step of applying an impulsion to
the ink of the present invention described above to fly the inkjet
recording ink to thereby form an image.
[0112] The ink flying unit is a unit configured to apply an
impulsion to the ink of the present invention described above to
fly the inkjet recording ink to thereby form an image. The ink
flying unit is not particularly limited, and examples thereof
include an inkjet head.
[0113] The inkjet head may be any of a piezo type that uses a
piezoelectric element as a pressure generation unit for
pressurizing the ink in an ink flow path, and deforming a vibration
plate that forms the wall surface of the ink flow path to thereby
change the cubic capacity within the ink flow path and discharge
ink droplets (see JP-A No. 02-51734), a so-called thermal type that
heats the ink within an ink flow path with a heat generating
resistor and generates bubbles (see JP-A No. 61-59911), an
electrostatic type that deforms a vibration plate that forms the
wall surface of an ink flow path with an electrostatic force
generated between the vibration plate and an electrode disposed
opposite to the vibration plate, to thereby change the cubic
capacity within the ink flow path and discharge ink droplets (see
JP-A No. 06-71882), etc.
[0114] The impulsion can be generated with, for example, the
impulsion generation unit. The impulsion is not particularly
limited, and an arbitrary impulsion may be selected according to
the purpose. Examples thereof include heat (temperature), pressure,
vibration, and light. One of these may be used alone, or two or
more of these may be used in combination. Among these, heat and
pressure are preferable.
[0115] Examples of the impulsion generation unit include a heater,
a pressure device, a piezoelectric element, a vibration generator,
an ultrasonic oscillator, and a light. Specific examples include a
piezoelectric actuator such as a piezoelectric element, a thermal
actuator that uses an electrothermal conversion element such as a
heat generating resistor to utilize a phase change due to film
boiling of a liquid, a shape-memory-alloy actuator that utilizes a
metal phase change due to a temperature change, and an
electrostatic actuator that utilizes an electrostatic force.
[0116] The method for flying the ink is not particularly limited,
and different methods are used depending on the kinds of the
impulsion. For example, when the impulsion is "heat", the ink
flying method may be to apply a thermal energy corresponding to a
recording signal to the ink in a recording head by means of, for
example, a thermal head, to generate bubbles in the ink by the
thermal energy, and jet out the ink from nozzle holes of the
recording head in the form of liquid droplets by the pressure of
the bubbles. When the impulsion is "pressure", the ink flying
method may be to apply a voltage to a piezoelectric element bonded
at a position in a so-called pressure chamber provided in an ink
flow path in a recording head, to bend the piezoelectric element
and shrink the cubic capacity in the pressure chamber, to thereby
jet out the ink from nozzle holes of the recording head in the form
of liquid droplets.
[0117] The size of the liquid droplets of the ink to be flown is
preferably from 3 pl to 40 pl, for example. The speed at which the
ink droplets are jetted out is preferably from 5 m/s to 20 m/s. The
drive frequency of the ink droplets is preferably 1 kHz or greater.
The resolution of the ink droplets is preferably 300 dpi or
greater.
[0118] The control unit is not particularly limited, and an
arbitrary control unit may be selected according to the purpose as
long as it can control the operations of each unit. Examples
thereof include devices such as a sequencer and a computer.
[0119] Here, an inkjet recording apparatus shown in FIG. 3 includes
an apparatus body 101, a paper feeding tray 102 attached to the
apparatus body 101 and configured to feed sheets, and a paper
ejection tray 103 attached to the apparatus body 101 and configured
to be stocked with sheets on which an image has been recorded
(formed). A top surface of a top cover 111 of the apparatus body
101 is an approximately flat surface. A front surface 112 of a
front cover of the apparatus body 101 is inclined rearward
obliquely with respect to the top surface. The paper ejection tray
103 and the paper feeding tray 102 are provided below the inclined
front surface 112 so as to protrude frontward (toward the shallower
side). An ink cartridge loading portion 104 is provided at an end
of the front surface 112 at a portion lower than the top cover 111,
so as to protrude frontward from the front surface 112. An
operation unit 105 including operation keys, a display, etc. is
provided on the top surface of the ink cartridge loading portion
104. The ink cartridge loading portion 104 has an openable/closable
front cover 115 for an ink cartridge to be attached and
detached.
[0120] As shown in FIG. 4 and FIG. 5, in the apparatus body 101, a
carriage 133 is supported slidably in a main-scanning direction by
a guide rod 131 and a stay 132, which are guide members bridged
laterally between unillustrated left and right side panels, and is
moved and scanned in a carriage scanning direction of FIG. 5 by an
unillustrated main scanning motor.
[0121] The carriage 133 is loaded with four recording heads 134,
which are inkjet heads configured to discharge ink droplets of
yellow, cyan, magenta, and black, respectively. A plurality of ink
discharge ports of each recording head are arranged in a direction
perpendicular to the main-scanning direction, and an ink
discharging side of each recording head faces downward.
[0122] The head constituting the recording head 134 may be a head
that includes as an energy generation unit for discharging an ink,
a piezoelectric actuator such as a piezoelectric element, a thermal
actuator that uses an electrothermal conversion element such as a
heat generating resistor to utilize a phase change due to film
boiling of a liquid, a shape-memory-alloy actuator that utilizes a
metal phase change due to a temperature change, an electrostatic
actuator that utilizes an electrostatic force, or the like.
[0123] A nozzle surface as an ink discharging portion of each
inkjet head is provided with a layer made of codeposited Ni/PTFE, a
silicone resin, and a fluorine-based water repellency imparting
agent, in order for discharge stability and a wiping property to be
improved. In the present invention, a surface energy on an inner
wall of a nozzle hole is determined depending on the liquid to be
discharged. It is more effective if a surface energy on the nozzle
surface is determined adaptively to the surface energy on the inner
wall of a nozzle hole. Hence, a treatment similar to that applied
to the nozzle surface should also be applied to the inner wall of a
nozzle hole, according to necessity.
[0124] The carriage 133 is mounted with sub tanks 135 for the
respective colors, which are configured to supply inks of the
respective colors to the respective recording heads 134. The sub
tanks 135 are refilled and supplied with the inks from the ink
cartridges loaded on the ink cartridge loading portion 104 through
unillustrated ink feeding tubes. A paper feeding unit configured to
feed sheets 142 stacked on a sheet stacker (pressure plate) 141 of
the paper feeding tray 102 includes a half-moon roll (paper feeding
roll) 143 configured to feed sheets one by one separately, and a
separation pad 144 opposed to the paper feeding roll 143 and made
of a material having a large friction coefficient. The separation
pad 144 is biased by the paper feeding roll 143.
[0125] A conveying unit configured to convey the sheet 142 fed by
the paper feeding unit below the recording heads 134 includes a
conveyor belt 151 configured to convey the sheet by electrostatic
adsorption, a counter roller 152 configured to convey the sheet 142
fed from the paper feeding unit via a guide 145 by sandwiching it
between itself and the conveyor belt 151, a conveyor guide 153
configured to change the direction of the sheet 142 conveyed
approximately vertically upward by approximately 90.degree. to make
the sheet follow the conveyor belt 151, and a leading end
pressurizing roll 155 biased toward the conveyor belt 151 by a
pressing member 154. It also includes a charging roller 156 which
is a charging unit configured to electrically charge the surface of
the conveyor belt 151.
[0126] The conveyor belt 151 is an endless belt, and hung between a
conveyor roller 157 and a tension roller 158 to move around in a
belt conveying direction. The conveyor belt 151 includes a surface
layer that is made of a resin material resistively uncontrolled and
having a pure thickness of about 40 .mu.m, e.g., an ETFE pure
material, and serves as a paper adsorbing surface, and a back layer
(an intermediate resistance layer, or an earth layer) made of the
same material as that of the surface layer and resistively
controlled with carbon. A guide member 61 is provided on the back
side of the conveyor belt 151 at a position corresponding to a
region where the recording heads 134 perform printing. A paper
ejection unit configured to eject a sheet 142 having had a print
recorded by the recording heads 134 includes a separation claw 171
configured to separate the sheet 142 from the conveyor belt 151, a
paper ejection roller 162 and a paper ejection roll 173, and the
paper ejection tray 103 below the paper ejection roller 162. A
both-side paper feeding unit 181 is mounted attachably and
detachably on the rear surface of the apparatus body 101. The
both-side paper feeding unit 181 retrieves a sheet 142 that is
returned by the conveyor belt 151 being rotated in a reverse
direction, and feeds it again to between the counter roller 152 and
the conveyor belt 151 by overturning it. A manual paper feeding
portion 182 is provided on the top of the both-side paper feeding
unit 181.
[0127] In the inkjet recording apparatus configured in this way,
sheets 142 are fed from the paper feeding unit one by one
separately. A sheet 142 fed approximately vertically upward is
guided by the guide 145, is conveyed by being sandwiched between
the conveyor belt 151 and the counter roller 152, and with its
leading end guided by the conveyor belt 153 and pressed by the
leading end pressurizing roll 155 onto the conveyor belt 151, has
its conveying direction changed by approximately 90.degree.. At the
moment, the conveyor belt 151 has been electrically charged by the
charging roller 156, and the sheet 142 is conveyed by being
electrostatically adsorbed to the conveyor belt 151. Hence, by the
recording heads 134 being driven in response to image signals while
the carriage 133 is moved, ink droplets are discharged and one line
is recorded on the sheet 142 that is being stopped, and then the
next line is recorded thereon after the sheet 142 is conveyed by a
predetermined amount. Upon reception of a recording completion
signal or a signal indicating that the rear end of the sheet 142
has reached the recording region, the recording operation is
terminated, and the sheet 142 is ejected onto the paper ejection
tray 103. When the amount of residual ink in any sub tank 135 is
detected to be "near end", a predetermined amount of ink is
replenished into the sub tank 135 from the ink cartridge.
[0128] As shown in FIG. 6, a maintenance device 91 according to the
present invention configured to maintain and restore the conditions
of the nozzles of the recording heads 34 is provided at a
non-printing region at one side in the scanning direction of the
carriage 33.
[0129] The maintenance device 91 includes caps 92 configured to cap
the nozzle surfaces of the recording heads 34 respectively, a wiper
blade 93 configured to wipe the nozzle surfaces, a blank discharge
receptacle 94 configured to receive liquid droplets during blank
discharge of discharging liquid droplets that do not contribute to
recording in order to remove thickened inks, a wiper cleaner 94
molded integrally with the blank discharge receptacle and serving
as a cleaning member for removing inks adhered to the wiper blade
93, and a cleaner roll 96 constituting a cleaner member for
pressing the wiper blade 93 onto the wiper cleaner during cleaning
of the wiper blade 93.
[0130] With the configuration described above, the wiper blade 93
is stuck up to the moving path of the recording heads 34 when the
recording heads pass the position of the wiper blade 93, and as a
result, the discharge ports of the recording heads 34 are
wiped.
<Ink Recorded Matter>
[0131] An ink recorded matter of the present invention includes a
base material, and an image formed on the base material with the
ink of the present invention described above.
[0132] The base material is not particularly limited, and an
arbitrary base material may be selected according to the purpose
unless it is a white base material. Examples thereof include gloss
paper, special paper, cloth, an OHP sheet, and a film. Among these,
a non-porous base material such as a film is preferable.
[0133] Here, the non-porous base material means such materials as a
resin film having a surface made of a plastic material, including a
transparent or colored polyvinyl chloride film, a polyethylene
terephthalate (PET) film, a polycarbonate film, a polyethylene
film, an acrylic film, a polypropylene film, a polyimide film, and
a polystyrene film, laminated paper, coated paper, glass, and
metals, that do not contain in the surface thereof, a paper
component such as wood paper, Japan paper, synthetic pulp paper,
and a synthetic fiber. One of these may be used alone, or two or
more of these may be used in combination.
[0134] A pigment ink containing an inorganic pigment as a colorant
can be a white ink when a white material is used as the inorganic
pigment. Such a white ink can not only be used favorably for
recording on a recording medium other than a white one, but such a
white ink can be used for image formation for recording on a
transparent medium such as an OHP sheet. Furthermore, by applying
such a white ink over a transparent recording medium to form a
white layer, and then forming an image thereon with an ink of a
different color, it is possible to obtain a clearer image having a
high image quality. In this case, it is possible to firstly form a
white layer over the transparent medium by applying the ink of the
present invention, and then form an image over the white layer with
inks such as a black ink and a color ink. It is also possible to
obtain a clear image by applying the ink of the present invention
after forming an image over a transparent medium with inks such as
a black ink and a color ink.
[0135] The black ink and the color ink are not particularly
limited, and may be the inks disclosed in, for example, JP-A No.
2009-280749 and Japanese Patent (JP-B) No. 5304023.
[0136] A material other than a white material may also be used as
the inorganic pigment. By selecting an inorganic pigment other than
a white material, it is possible to form a layer of an arbitrary
color.
[0137] In the ink of the present invention, the inorganic pigment
hardly settles, and can easily re-disperse even if it settles.
Therefore, an ink recorded matter obtained by using the ink of the
present invention has a high image quality with no smudging and an
excellent aging stability, and can be used for various purposes as
a handout or the like on which various prints or images are
recorded.
EXAMPLES
[0138] Examples of the present invention will be explained below.
The present invention is not limited to these Examples by any
means.
(Preparation Example 1 of Inorganic Pigment Having Surface
Hydrophobicity)
[0139] Preparation of Titanium Dioxide Surface-Treated with
Silicone-
[0140] Titanium dioxide (CR-50 manufactured by Ishihara Sangyo
Kaisha, Ltd.) (10 parts by mass) that had been dried with a
reduced-pressure dryer at 110.degree. C. for 2 days was added in a
200 mL flask equipped with an isobaric pressure funnel, which was
then purged with a nitrogen gas. A solution obtained by diluting a
reactive silicone oil (KF-99 manufactured by Shin-Etsu Chemical
Co., Ltd.) (2 parts by mass) with a dehydrated toluene (40 parts by
mass) was added gradually thereto through the dropping funnel, and
they were stirred. After the dropping was completed, they were
heated in an oil bath to distill toluene away, and then reacted at
150.degree. C. for 3 hours. After the reaction was completed, a
solid content was recovered, washed sufficiently with toluene and
then with methanol, and after this, dried at reduced pressure at
60.degree. C. for 1 day, to thereby obtain titanium dioxide
surface-treated with silicone.
(Preparation Example 2 of Inorganic Pigment Having Surface
Hydrophobicity)
[0141] -Preparation of Titanium Dioxide Surface-Treated with
Alkyl-
[0142] A 5 mM octadecyltrimethoxysilane toluene solution (50 parts
by mass), titanium dioxide (CR-50 manufactured by Ishihara Sangyo
Kaisha, Ltd.) (10 parts by mass) that had been dried with a
reduced-pressure dryer at 110.degree. C. for 2 days, and zirconia
beads having a diameter of 4 mm (200 parts by mass) were added and
sealed in a glass bottle purged with a nitrogen gas, and after
this, reacted for 2 days while being rotated with a mix rotor.
After this, the beads were separated therefrom through a sieve, and
then a solid content was filtered and recovered. After this, the
solid content was washed sufficiently with toluene and then with
methanol. After this, the solid content was dried at reduced
pressure at 60.degree. C. for 1 day, to thereby obtain titanium
dioxide surface-treated with alkyl.
(Preparation Example 3 of Inorganic Pigment Having Surface
Hydrophobicity)
[0143] -Preparation of Silicon Dioxide Surface-Treated with
Silicone-
[0144] Silicon dioxide surface-treated with silicone was obtained
in the same manner as in Preparation Example 1 of the inorganic
pigment having a surface hydrophobicity, except that spherical
silica having a particle diameter of 0.4 .mu.m (manufactured by
Sakai Chemical Industry Co., Ltd.) was used.
<Evaluation of Surface Hydrophobicity>
[0145] In the evaluation of surface hydrophobicity, pure water (10
g) and an inorganic pigment (2 g) were added in a 30 mL sample
bottle (SV-30 manufactured by Nichidenrika-Glass Co., Ltd.) in
which a stirring bar was put, stirred and mixed at 400 rpm for 10
minutes with a stirrer (MS-2T manufactured by Ishii Laboratory
Works Co., Ltd.), and then kept stationary for 30 minutes. In this
case, when the inorganic pigment was wholly floating without having
settled, it was judged to have a "surface hydrophobicity". When the
inorganic pigment had settled even partially, it was judged to have
no "surface hydrophobicity".
[0146] All of the inorganic pigments having a surface
hydrophobicity of Preparation Examples 1 to 3 were evaluated as
"having a surface hydrophobicity". Further, TiO.sub.2
surface-treated with a hydrophobic silicone (CR-63 manufactured by
Ishihara Sangyo Kaisha, Ltd.) and TiO.sub.2 surface-treated with a
hydrophobic silicone (MTY-02 manufactured by Tayca Corporation),
which were to be used in Examples described below, were evaluated
as "having a surface hydrophobicity".
[0147] In contrast, all of hydrophilized TiO.sub.2 (CR-60
manufactured by Ishihara Sangyo Kaisha, Ltd.), hydrophilized
TiO.sub.2 (CR-50 manufactured by Ishihara Sangyo Kaisha, Ltd.), and
non-treated SiO.sub.2 (spherical silica having a particle diameter
of 0.4 .mu.m, manufactured by Ishihara Sangyo Kaisha, Ltd.) were
evaluated as "having no surface hydrophobicity".
Example 1
Preparation of Dispersion Liquid
[0148] Ion-exchanged water (11.4 parts by mass),
3-methyl-1,3-butanediol (12 parts by mass), and as a dispersant,
DISPERBYK-190 (manufactured by Byk Chemie GmbH) (0.6 parts by mass)
were added in a vial container, and stirred lightly and
homogenized. After this, the titanium dioxide surface-treated with
silicone of Preparation Example 1 (6 parts by mass) was added
thereto, and they were irradiated with ultrasonic waves (600 W) at
50.degree. C. for 3 hours, to thereby obtain a dispersion liquid.
After the obtained dispersion liquid was slowly cooled to room
temperature, a particle diameter (D50) of the dispersion liquid at
a 50% cumulative mean in a volume-basis particle size distribution
thereof was measured with a granularity distribution analyzer
(MICROTRACK UPA-EX150 manufactured by Nikkiso Co., Ltd.), and it
was 331 nm.
-Preparation of Vehicle-
[0149] A vehicle was prepared by mixing the raw materials described
below. [0150] ACRIT WEM-321U (acrylic urethane resin particles,
manufactured by Taisei Kako Co., Ltd., with a solid content
concentration of 38% by mass) - - - 12.3 parts by mass [0151]
Glycerin - - - 11.7 parts by mass [0152] 1,3-butanediol - - - 35.2
parts by mass [0153] 2-ethyl-1,3-hexanediol - - - 6.3 parts by mass
[0154] POLYFOX PF-156A (anionic fluorosurfactant, manufactured by
Omnova Solutions Inc.) - - - 5.2 parts by mass [0155] PROXEL LV
(antiseptic/mildewcide, 1,2-benzisothiazolin-3-one, manufactured by
Nitto Denko Avecia Inc.) - - - 0.3 parts by mass [0156] Triethanol
amine - - - 0.2 parts by mass [0157] Ion-exchanged water - - - 28.9
parts by mass
[0158] The prepared dispersion liquid and the vehicle were mixed in
equal amounts in a vial container, to thereby prepare an ink.
[0159] The viscosity of the obtained ink measured with RE-80L
VISCOMETER (manufactured by Toki Sangyo Co., Ltd.) was 11.4 mPas at
25.degree. C. A particle diameter (D50) of the inorganic pigment in
the ink at a 50% cumulative mean was confirmed to be substantially
not different from that of the dispersion liquid.
[0160] Next, with the ink of Example 1, a settling property,
re-dispersibility, whiteness of a printed image were evaluated in
the manners described below. The results are shown in Table 2.
<Settling Property of Inorganic Pigment>
[0161] The settling property of the inorganic pigment in the ink
was measured with TURBISCAN (MA2000 manufactured by Eko Instruments
Co., Ltd.).
[0162] The ink was subjected to ultrasonic dispersion (at 100 W,
for 40 minutes) with an ultrasonic cleaner (US-3 manufactured by As
One Corporation) and homogenized, and then poured into a glass cell
specially prepared for the instrument in an amount of 5.5 mL with a
pipette. Measurement was performed 30 minutes later when the liquid
surface of the ink in the cell had stabilized, and this timing was
regarded as a start of evaluation of the settling property. Then,
the ink was kept stationary at 23.degree. C., and measured until
240 hours later, to thereby observe the settling property as a
deviation with respect to the start of evaluation of the settling
property. The settling property was observed mainly by measuring
change of backscattering due to production of a supernatant, by
performing a cumulative calculation (in a relative value mode) of
the peaks of the backscattering, and was evaluated based on the
criteria below.
[Evaluation Criteria]
[0163] A: A relative change of the backscattering at 240 hours
since the start of evaluation was less than 5%.
[0164] B: A relative change of the backscattering at 240 hours
since the start of evaluation was 5% or greater but less than
10%.
[0165] C: A relative change of the backscattering at 240 hours
since the start of evaluation was 10% or greater.
<Re-dispersibility of Settled Inorganic Pigment>
[0166] The prepared ink (30 mL) was poured in a 50 mL vial
container, and kept stationary at room temperature (25.degree. C.)
for 1 month. After this, re-dispersibility of any settled inorganic
pigment was evaluated based on the criteria below.
[Evaluation Criteria]
[0167] A: When the vial container was shaken with a hand for 10
seconds, the settling of the inorganic pigment disappeared, and the
particle diameter before stationary keeping was restored.
[0168] B: When the settled inorganic pigment in the vial container
was subjected to ultrasonic irradiation (at 100 W) with an
ultrasonic cleaner (US-3 manufactured by As One Corporation) for 2
minutes, the settling of the inorganic pigment disappeared, and the
particle diameter before stationary keeping was restored.
[0169] C: Even when the settled inorganic pigment in the vial
container was subjected to ultrasonic irradiation (at 100 W) with
an ultrasonic cleaner (US-3 manufactured by As One Corporation) for
longer than 2 minutes, the settling of the inorganic pigment did
not disappear.
<Whiteness of Printed Image>
[0170] The ink was filled in an ink cartridge. Then, with an inkjet
printer (IPSIO GX3000 manufactured by Ricoh Company, Ltd.), it was
seen to it that all nozzles were filled with the ink and no
abnormal image would be produced, and the discharge amount was
adjusted such that an amount of ink deposition on a recording
medium would be 20 g/m.sup.2. After this, a 50 mm.times.50 mm solid
image was printed on an OHP sheet as a recording medium. With a
commercially available black sheet underlaid below the printed OHP
sheet, the luminosity (L*) of the printed portion was measured with
a spectrophotometric densitometer X-RITE 938 (manufactured by
X-rite Inc.), and evaluated based on the criteria below. For
reference, a L* value measured in a state that an un-printed OHP
sheet was overlaid over a black sheet was 22.4
[Evaluation Criteria]
[0171] A: L* value was 75 or greater.
[0172] B: L* value was 65 or greater but less than 75.
[0173] C: L* value was less than 65.
Examples 2 to 11 and Comparative Examples 1 to 3
[0174] Inorganic pigment dispersion liquids were prepared in the
same manner as in Example 1, except that inorganic pigments and
water-soluble organic solvents shown in Table 1 were used unlike in
Example 1.
[0175] With the obtained inorganic pigment dispersion liquids, inks
of Examples 2 to 11 and Comparative Examples 1 to 3 were prepared
in the same manner as in Example 1.
[0176] With each of the obtained inks, a settling property,
re-dispersibility, whiteness of a printed image were evaluated in
the same manner as in Example 1. The results are shown in Table
2.
Example 12
[0177] An ink was prepared in the same manner as in Example 1,
except that a vehicle described below was used unlike in Example
1.
[0178] With the obtained ink, a settling property,
re-dispersibility, and whiteness of a printed image were evaluated
in the same manner as in Example 1. The results are shown in Table
2.
-Preparation of Vehicle-
[0179] A vehicle was obtained by mixing the raw materials described
below. [0180] ACRIT WEM-321U (acrylic urethane resin particles,
manufactured by Taisei Kako Co., Ltd., with a solid content
concentration of 38% by mass) - - - 52.6 parts by mass [0181]
Glycerin - - - 8.9 parts by mass [0182] 1,3-butanediol - - - 23
parts by mass [0183] 2-ethyl-1,3-hexanediol - - - 6.3 parts by mass
[0184] POLYFOX PF-156A (anionic fluorosurfactant, manufactured by
Omnova Solutions Inc.) - - - 5.2 parts by mass [0185] PROXEL LV
(antiseptic/mildewcide, 1,2-benzisothiazolin-3-one, manufactured by
Nitto Denko Avecia Inc.) - - - 0.3 parts by mass [0186] Triethanol
amine - - - 0.2 parts by mass [0187] Ion-exchanged water - - - 3.5
parts by mass
Example 13
[0188] An ink was prepared in the same manner as in Example 1,
except that a vehicle described below was used unlike in Example
1.
[0189] With the obtained ink, a settling property,
re-dispersibility, and whiteness of a printed image were evaluated
in the same manner as in Example 1. The results are shown in Table
2.
-Preparation of Vehicle-
[0190] A vehicle was obtained by mixing the raw materials described
below. [0191] ACRIT WEM-321U (acrylic urethane resin particles,
manufactured by Taisei Kako Co., Ltd., with a solid content
concentration of 38% by mass) - - - 0.3 parts by mass [0192]
Glycerin - - - 11.7 parts by mass [0193] 1,3-butanediol - - - 35.2
parts by mass [0194] 2-ethyl-1,3-hexanediol - - - 6.3 parts by mass
[0195] POLYFOX PF-156A (anionic fluorosurfactant, manufactured by
Omnova Solutions Inc.) - - - 5.2 parts by mass [0196] PROXEL LV
(antiseptic/mildewcide, 1,2-benzisothiazolin-3-one, manufactured by
Nitto Denko Avecia Inc.) - - - 0.3 parts by mass [0197] Triethanol
amine - - - 0.2 parts by mass [0198] Ion-exchanged water - - - 40.8
parts by mass
Example 14
[0199] An ink was prepared in the same manner as in Example 1,
except that a vehicle described below was used unlike in Example
1.
[0200] With the obtained ink, a settling property,
re-dispersibility, and whiteness of a printed image were evaluated
in the same manner as in Example 1. The results are shown in Table
2.
-Preparation of Vehicle-
[0201] A vehicle was obtained by mixing the raw materials described
below. [0202] ACRIT WEM-321U (acrylic urethane resin particles,
manufactured by Taisei Kako Co., Ltd., with a solid content
concentration of 38% by mass) - - - 26.3 parts by mass [0203]
Glycerin - - - 11.7 parts by mass [0204] 1,3-butanediol - - - 35.2
parts by mass [0205] 2-ethyl-1,3-hexanediol - - - 6.3 parts by mass
[0206] POLYFOX PF-156A (anionic fluorosurfactant, manufactured by
Omnova Solutions Inc.) - - - 5.2 parts by mass [0207] PROXEL LV
(antiseptic/mildewcide, 1,2-benzisothiazolin-3-one, manufactured by
Nitto Denko Avecia Inc.) - - - 0.3 parts by mass [0208] Triethanol
amine - - - 0.2 parts by mass [0209] Ion-exchanged water - - - 14.8
parts by mass
Example 15
[0210] An ink was prepared in the same manner as in Example 1,
except that a vehicle described below was used unlike in Example
1.
[0211] With the obtained ink, a settling property,
re-dispersibility, and whiteness of a printed image were evaluated
in the same manner as in Example 1. The results are shown in Table
2.
-Preparation of Vehicle-
[0212] A vehicle was obtained by mixing the raw materials described
below. [0213] ACRIT WBR-2018 (polyurethane resin particles,
manufactured by Taisei Fine Chemical Co., Ltd., with a solid
content concentration of 32.5% by mass) - - - 15 parts by mass
[0214] Glycerin - - - 11.7 parts by mass [0215] 1,3-butanediol - -
- 35.2 parts by mass [0216] 2-ethyl-1,3-hexanediol - - - 6.3 parts
by mass [0217] POLYFOX PF-156A (anionic fluorosurfactant,
manufactured by Omnova Solutions Inc.) - - - 5.2 parts by mass
[0218] PROXEL LV (antiseptic/mildewcide,
1,2-benzisothiazolin-3-one, manufactured by Nitto Denko Avecia
Inc.) - - - 0.3 parts by mass [0219] Triethanol amine - - - 0.2
parts by mass [0220] Ion-exchanged water - - - 26.1 parts by
mass
Example 16
[0221] An ink was prepared in the same manner as in Example 1,
except that a vehicle described below was used unlike in Example
1.
[0222] With the obtained ink, a settling property,
re-dispersibility, and whiteness of a printed image were evaluated
in the same manner as in Example 1. The results are shown in Table
2. [0223] CHALINE R-170EM (acrylic silicone resin particles,
manufactured by Nissin Chemical Industry Co., Ltd., with a solid
content concentration of 45% by mass) - - - 18.5 parts by mass
[0224] Glycerin - - - 11.7 parts by mass [0225] 1,3-butanediol - -
- 35.2 parts by mass [0226] 2-ethyl-1,3-hexanediol - - - 6.3 parts
by mass [0227] POLYFOX PF-156A (anionic fluorosurfactant,
manufactured by Omnova Solutions Inc.) - - - 5.2 parts by mass
[0228] PROXEL LV (antiseptic/mildewcide,
1,2-benzisothiazolin-3-one, manufactured by Nitto Denko Avecia
Inc.) - - - 0.3 parts by mass [0229] Triethanol amine - - - 0.2
parts by mass [0230] Ion-exchanged water - - - 22.6 parts by
mass
Comparative Example 4
[0231] An ink was prepared in the same manner as in Example 1,
except that a vehicle described below was used unlike in Example
1.
[0232] With the obtained ink, a settling property,
re-dispersibility, and whiteness of a printed image were evaluated
in the same manner as in Example 1. The results are shown in Table
2.
-Preparation of Vehicle-
[0233] A vehicle was obtained by mixing the raw materials described
below. [0234] Glycerin - - - 11.7 parts by mass [0235]
1,3-butanediol - - - 35.2 parts by mass [0236]
2-ethyl-1,3-hexanediol - - - 6.3 parts by mass [0237] POLYFOX
PF-156A (anionic fluorosurfactant, manufactured by Omnova Solutions
Inc.) - - - 5.2 parts by mass [0238] PROXEL LV
(antiseptic/mildewcide, 1,2-benzisothiazolin-3-one, manufactured by
Nitto Denko Avecia Inc.) - - - 0.3 parts by mass [0239] Triethanol
amine - - - 0.2 parts by mass [0240] Ion-exchanged water - - - 41.1
parts by mass
Comparative Example 5
[0241] A titanium oxide dispersion liquid described in Example 1 of
JP-A No. 2011-225867 (a product obtained by treating with a silane
coupling agent, a surface-treated titanium oxide co-present with
alumina and silica at an alumina:silica mass ratio of 2:3) was
prepared. A particle diameter (D50) of this pigment dispersion
liquid at a 50% cumulative mean in a volume-basis particle size
distribution thereof was measured with a granularity distribution
analyzer (MICROTRACK UPA-EX150 manufactured by Nikkiso Co., Ltd.),
and it was 287 nm.
[0242] An ink of Comparative Example 5 was prepared by adding
glycerin (10 parts by mass), and as a surfactant, POLYFOX PF-156A
(anionic fluorosurfactant, manufactured by Omnova Solutions Inc.)
(1.5 parts by mass) in the obtained pigment dispersion liquid (88.5
parts by mass), and stirring them.
[0243] With the obtained ink, a settling property,
re-dispersibility, and whiteness of a printed image were evaluated
in the same manner as in Example 1. The results are shown in Table
2.
Comparative Example 6
[0244] An ink of Comparative Example 6 was prepared by adding
glycerin (3 parts by mass), JONCRYL 60J (water-soluble acrylic
polymer, with a weight average molecular weight of 8,500, a 34% by
mass aqueous solution, manufactured by BASF Japan Ltd.) (7 parts by
mass), and as a surfactant, POLYFOX PF-156A (anionic
fluorosurfactant, manufactured by Omnova Solutions Inc.) (1.5 parts
by mass) in the titanium oxide dispersion liquid prepared in
Comparative Example 5 (88.5 parts by mass), and stirring them.
[0245] With the obtained ink, a settling property,
re-dispersibility, and whiteness of a printed image were evaluated
in the same manner as in Example 1. The results are shown in Table
2.
TABLE-US-00001 TABLE 1-1 Pigment dispersion liquid Water-soluble
organic solvent Inorganic pigment 3-methoxy- Content 3-methyl-1,3-
3-methyl- (part by butanediol (part 1-butanol (part Kind mass) by
mass) by mass) Ex. 1 TiO.sub.2 surface -treated with silicone 6 12
-- of Preparation Example 1 Ex. 2 TiO.sub.2 surface -treated with
silicone 6 -- 18 of Preparation Example 1 Ex. 3 TiO.sub.2
surface-treated with 6 18 -- hydrophobic silicone (CR-63) Ex. 4
TiO.sub.2 surface-treated with 6 -- 10 hydrophobic silicone (CR-63)
Ex. 5 TiO.sub.2 surface-treated with alkyl of 6 12 -- Preparation
Example 2 Ex. 6 TiO.sub.2 surface-treated with alkyl of 6 -- 18
Preparation Example 2 Ex. 7 TiO.sub.2 surface-treated with 6 -- 18
hydrophobic silicone (MTY-02) Ex. 8 TiO.sub.2 surface -treated with
silicone 6 3.5 -- of Preparation Example 1 Ex. 9 TiO.sub.2 surface
-treated with silicone 6 -- 2 of Preparation Example 1 Ex. 10
TiO.sub.2 surface -treated with silicone 6 19.5 -- of Preparation
Example 1 Ex. 11 TiO.sub.2 surface -treated with silicone 6 -- 12
of Preparation Example 3 Comp. Hydrophilized TiO.sub.2 (CR-60) 6 12
-- Ex. 1 Comp. Hydrophilized TiO.sub.2 (CR-50) 6 -- 18 Ex. 2 Comp.
Non-treated SiO.sub.2 (by Sakai 6 -- 12 Ex. 3 Chemical Industry
Co., Ltd.) Comp. TiO.sub.2 surface -treated with silicone 6 12 --
Ex. 4 of Preparation Example 1
TABLE-US-00002 TABLE 1-2 Pigment dispersion liquid Dispersant
Ion-exchanged Total Median diameter DISPERBYK-190 water (part (part
by (D50) (nm) of (parts by mass) by mass) mass) dispersion liquid
Ex. 1 0.6 11.4 30 331 Ex. 2 0.6 5.4 30 263 Ex. 3 0.6 5.4 30 352 Ex.
4 0.6 13.4 30 320 Ex. 5 0.6 11.4 30 297 Ex. 6 0.6 5.4 30 278 Ex. 7
0.6 5.4 30 195 Ex. 8 0.6 19.9 30 657 Ex. 9 0.6 21.4 30 483 Ex. 10
0.6 4.9 30 246 Ex. 11 0.6 11.4 30 516 Comp. 0.6 11.4 30 368 Ex. 1
Comp. 0.6 5.4 30 349 Ex. 2 Comp. 0.6 11.4 30 475 Ex. 3 Comp. 0.6
11.4 30 331 Ex. 4
[0246] TiO.sub.2 surface-treated with a hydrophobic silicone (CR-63
manufactured by Ishihara Sangyo Kaisha, Ltd.) [0247] TiO.sub.2
surface-treated with a hydrophobic silicone (MTY-02 manufactured by
Tayca Corporation) [0248] Hydrophilized TiO.sub.2 (CR-60
manufactured by Ishihara Sangyo Kaisha, Ltd.) [0249] Hydrophilized
TiO.sub.2 (CR-50 manufactured by Ishihara Sangyo Kaisha, Ltd.)
[0250] Non-treated SiO.sub.2 (spherical silica having a particle
diameter of 0.4 .mu.m, manufactured by Ishihara Sangyo Kaisha,
Ltd.)
TABLE-US-00003 [0250] TABLE 2 Resin Ink properties particle Median
content diameter (solid (D50) White- content) (nm) ness in ink of
of (% by inorganic Viscosity Settling Re- printed mass) pigment
(mPa s) property dispersibility image Ex. 1 2.4 316 11.4 A A A Ex.
2 2.4 251 10.3 A A A Ex. 3 2.4 340 16.8 A A A Ex. 4 2.4 298 3.94 A
A A Ex. 5 2.4 285 15.6 A A A Ex. 6 2.4 259 11.2 A A A Ex. 7 2.4 185
10.8 A A B Ex. 8 2.4 631 2.93 B B A Ex. 9 2.4 452 1.85 B B A Ex. 10
2.4 261 21.2 A B B Ex. 11 2.4 483 9.84 A A B Ex. 12 10 309 18.3 A A
A Ex. 13 0.05 297 5.45 B B A Ex. 14 5 333 13.6 A A A Ex. 15 2.5 321
12.2 A A A Ex. 16 4.2 312 14.8 A A A Comp. 2.4 360 10.5 C C A Ex. 1
Comp. 2.4 371 8.98 C C A Ex. 2 Comp. 2.4 460 10.3 C C C Ex. 3 Comp.
Absent 322 8.81 C C B Ex. 4 Comp. Absent 308 9.64 C B A Ex. 5 Comp.
Absent 295 10.1 C B A Ex. 6
[0251] From the results of Table 2, it was revealed that all of
Examples 1 to 16 that included an inorganic pigment having a
surface hydrophobicity and resin particles had all of an excellent
settling property, an excellent re-dispersibility, and an excellent
whiteness of a printed image.
[0252] It was revealed that Comparative Example 6 was poor in the
settling property and re-dispersibility, because it used a
water-soluble acrylic polymer.
[0253] Aspects of the present invention are as follows, for
example.
<1> An ink, including at least:
[0254] an inorganic pigment having a surface hydrophobicity;
[0255] resin particles; and
[0256] water.
<2> The ink according to <1>,
[0257] wherein the inorganic pigment having a surface
hydrophobicity is titanium dioxide.
<3> The ink according to <1> or <2>,
[0258] wherein the inorganic pigment having a surface
hydrophobicity obtained by applying a silicone surface treatment or
an alkyl surface treatment to an inorganic pigment.
<4> The ink according to any one of <1> to
<3>,
[0259] wherein a particle diameter (D50) of the inorganic pigment
having a surface hydrophobicity at a 50% cumulative mean in a
volume-basis particle size distribution thereof is from 200 nm to
600 nm.
<5> The ink according to any one of <1> to
<4>,
[0260] wherein the resin particles are at least one kind selected
from the group consisting of styrene acrylic resin particles,
acrylic silicone resin particles, polyurethane resin particles, and
acrylic urethane resin particles.
<6> The ink according to any one of <1> to
<5>,
[0261] wherein a content of the resin particles is from 0.1% by
mass to 20% by mass.
<7> The ink according to any one of <1> to
<6>,
[0262] wherein the ink is a white ink.
<8> The ink according to any one of <1> to
<7>,
[0263] wherein the ink is for inkjet recording.
<9> An ink cartridge, including:
[0264] the ink according to any one of <1> to <8>;
and
[0265] a container containing the ink.
<10> An inkjet recording apparatus, including at least:
[0266] an ink flying unit configured to apply an impulsion to the
ink according to any one of <1> to <8> to fly the ink,
to thereby record an image on a recording medium.
<11> An inkjet recording method, including at least:
[0267] applying an impulsion to the ink according to any one of
<1> to <8> to fly the ink, to thereby record an image
on a recording medium.
<12> An image forming method, including:
[0268] forming an image over a base material using the ink
according to any one of <1> to <7>.
<13> An ink recorded matter, including:
[0269] an image formed over a base material using the ink according
to any one of <1> to <8>.
[0270] This application claims priority to Japanese application No.
2013-268914, filed on Dec. 26, 2013 and incorporated herein by
reference.
* * * * *
References