U.S. patent application number 09/790253 was filed with the patent office on 2001-10-25 for ink composition suitable for use in ink jet recording.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Yatake, Masahiro.
Application Number | 20010032566 09/790253 |
Document ID | / |
Family ID | 26585927 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010032566 |
Kind Code |
A1 |
Yatake, Masahiro |
October 25, 2001 |
Ink composition suitable for use in ink jet recording
Abstract
An ink composition is provided which can yield prints having
high color density and, even when printed on recycled papers,
causes no significant feathering or bleeding and, at the same time,
has excellent ejection stability and storage stability, The ink
composition comprises a colorant, water, and a compound represented
by formula (I): R-(EO)n-(PO)m-M wherein R represents an alkoxy
group having in its molecular chain an acetylene bond; EO
represents an ethyleneoxy group; and PO represents a propyleneoxy
group; n and m each represent a repeating unit in terms of an
average value in the whole system. EO and PO may be present in any
order in the molecule. M represents a terminal group attached to
the terminal oxygen atom of EO or PO.
Inventors: |
Yatake, Masahiro;
(Nagano-Ken, JP) |
Correspondence
Address: |
LADAS & PARRY
26 West 61st Street
New York
NY
10023
US
|
Assignee: |
SEIKO EPSON CORPORATION
|
Family ID: |
26585927 |
Appl. No.: |
09/790253 |
Filed: |
February 21, 2001 |
Current U.S.
Class: |
106/31.58 ;
106/31.59; 106/31.86; 106/31.89; 347/100 |
Current CPC
Class: |
C09D 11/38 20130101 |
Class at
Publication: |
106/31.58 ;
347/100; 106/31.59; 106/31.86; 106/31.89 |
International
Class: |
C09D 011/00; G01D
011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2000 |
JP |
2000-046399 |
Apr 21, 2000 |
JP |
2000-121464 |
Claims
1. An ink composition comprising a colorant, water, and a compound
represented by formula (I):RO[EO.paren close-st..sub.nPO.paren
close-st..sub.m]M (I)wherein R represents a group represented by
formula; 5R.sup.1 represents an alkyl, cycloalkyl, or aryl group;
EO represents an ethyleneoxy group; PO represents a propyleneoxy
group; m and n each are independently 0 (zero) or a natural number
of not less than 1, provided that m+n>1; EO and PO may be
arranged, regardless of order in the parentheses of formula (I),
randomly or as blocks joined together; R.sup.2 and R.sup.3 each
independently represent a hydrogen atom or an alkyl group; and M is
a group attached to the terminal oxygen atom within the
parentheses.
2. The ink composition according to claim 1, wherein m in formula
(I) is 0 (zero).
3. The ink composition according to claim 2, wherein n in formula
(I) is 1 to 10.
4. The ink composition according to claim 1, wherein m in formula
(I) is not 0 (zero).
5. The ink composition according to claim 4, wherein n in formula
(I) is 0 (zero) to 10 and m is 1 to 5.
6. The ink composition according to any one of claims 1 to 5,
wherein M in formula (I) is (i) a hydrogen atom, (ii) an alkali
metal, an inorganic base, or an organic base, or (iii) a residue of
an acid selected from the group consisting of sulfonic acid,
phosphoric acid, and boric acid, or a salt of said acid with said
compound (ii).
7. The ink composition according to any one of claims 1 to 6,
wherein the compound represented by formula (I) has an average
molecular weight of not more than 2000.
8. The ink composition according to any one of claims 1 to 7,
wherein the total number of carbons in R in formula (I) is 4 to
50.
9. The ink composition according to any one of claims 1 to 8,
wherein R.sup.1 in formula (II) has a branched structure.
10. The ink composition according to any one of claims 1 to 9,
which further comprises a penetrating agent selected from the group
consisting of propylene glycol monobutyl ether, dipropylene glycol
monobutyl ether, and mixtures thereof.
11. The ink composition according to claim 10, wherein the content
of the penetrating agent is not more than 10% by weight.
12. The ink composition according to claim 10 or 11, wherein the
weight ratio of the compound represented by formula (I) to the
penetrating agent is 1:0 to 1:10.
13. The ink composition according to any one of claims 1 to 12,
which further comprises an acetylene glycol surfactant.
14. The ink composition according to claim 13, wherein the content
of the acetylene glycol surfactant is not more than 5% by
weight.
15. The ink composition according to claim 13 or 14, wherein the
weight ratio of the compound represented by formula (I) to the
acetylene glycol surfactant is 1:0 (zero) to 1:3.
16. The ink composition according to any one of claims 1 to 15,
which further comprises diethylene glycol monobutyl ether or
triethylene glycol monobutyl ether.
17. The ink composition according to claim 16, wherein the content
of diethylene glycol monobutyl ether or triethylene glycol
monobutyl ether is not more than 20% by weight.
18. The ink composition according to claim 16 or 17, wherein the
weight ratio of the compound represented by formula (I) to
diethylene glycol monobutyl ether or triethylene glycol monobutyl
ether is 1:0 (zero) to 1:10.
19. The ink composition according to any one of claims 1 to 18,
wherein the colorant is a member selected from the group consisting
of dyes, pigments, and mixtures thereof.
20. The ink composition according to claim 19, wherein the pigment
has been surface treated to introduce a hydrophilic group into the
pigment and thus to render the pigment self-dispersible in
water.
21. The ink composition according to any one of claims 1 to 20,
which is used in ink jet recording.
22. A recording method comprising the step of depositing an ink
composition onto a recording medium to perform printing, the ink
composition being one according to any one of claims 1 to 20.
23. An ink jet recording method comprising the steps of: ejecting
droplets of an ink composition; and depositing the droplets onto a
recording medium to perform printing, the ink composition being one
according to any one of claims 1 to 20.
24. A record produced by the recording method according to claim 22
or 23.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an ink composition suitable
for use in ink jet recording.
[0003] 2. Background Art
[0004] Ink jet recording is a printing method wherein droplets of
an ink composition are ejected and deposited on recording media,
such as paper, to print, for example, letters or figures. The
method have the advantage of realizing images, having high quality
with high resolution at a high speed by means of a relatively
inexpensive apparatus.
[0005] Examples of ink jet recording methods which have been
developed and put to practical use include: a method wherein an
electric signal is converted to a mechanical signal using an
electrostrictive element to intermittently eject an ink reservoired
in a nozzle head section, thereby recording letters or symbols on
the surface of a recording medium; and a method wherein an ink,
reservoired in a nozzle head section, in its portion very close to
the ejection portion is rapidly heated to create a bubble and the
ink is intermittently ejected by volume expansion created by the
bubble to record letters or symbols on the surface of a recording
medium.
[0006] Various properties required of ink compositions for an ink
jet recording method are such that the drying property of the print
is good, no significant feathering is created in printed images,
uniform printing can be realized on the surface of conventional
recording media, and, in the case of multi-color printing, mixing
between adjacent colors does not occur. In particular, it is
important for the ink compositions for ink jet printing to realize
good images having no feathering or bleeding attributable to paper
fibers of paper as a recording medium.
[0007] In conventional inks, particularly pigment-based inks, a
technique has been proposed wherein the penetration of ink is
mainly suppressed to suppress wetting of the surface of paper by
the ink and consequently to allow ink droplets to stay near the
surface of paper, whereby print quality is ensured.
[0008] On the other hand, an attempt has also been made to increase
the penetration of the ink composition into paper to suppress
feathering or bleeding. For example, the use of an additive for
lowering the surface tension of the ink composition to increase the
penetration speed of the ink composition into paper and thus to
reduce feathering or bleeding has been proposed. More specifically,
the use of diethylene glycol monobutyl ether (U.S. Pat. No.
5,156,675) or Surfynol 465 (manufactured by Air Products and
Chemicals Inc., U.S.A.) (U.S. Pat. No. 5,183,502) as an acetylene
glycol surfactant or the combined use of diethylene glycol
monobutyl ether and Surfynol 465 (U.S. Pat. No. 5,196,056) has been
proposed. Further, an ink composition has been proposed which
contains, as a wetting agent, polyglycerin (Japanese Patent
Laid-Open No. 152170/1991), polyglycerin with an ethyleneoxy group
added thereto (Japanese Patent Laid-Open No. 328644/1997), or
glycerin with an ethyleneoxy group added thereto (Japanese Patent
Laid-Open No. 18465/1992).
[0009] Further, the addition of a glycol ether compound to an ink
composition has been proposed from the viewpoint of improving the
penetration of the ink composition into paper. For example,
Japanese Patent Laid-Open No. 147861/1981 describes the addition of
triethylene glycol monomethyl ether to a pigment-containing ink
composition, and Japanese Patent Laid-Open No. 111165/1997
describes an example of a combination of a water-soluble dye with
ethers of ethylene glycol, diethylene glycol, or triethylene
glycol.
[0010] For the above-described conventional ink compositions,
however, there is still room for improvement, for example, in the
effect of preventing feathering or bleeding, storage stability, and
fixation of prints.
SUMMARY OF THE INVENTION
[0011] The present inventors have now found that the addition of a
compound having a combination of an acetylene structure with
ethyleneoxy or propyleneoxy groups can realize ink compositions
having various excellent properties, excellent drying properties
and excellent storage stability and thus that the ink composition
can yield images having no significant feathering or bleeding on
various recording media, particularly on plain papers and recycled
papers. The present inventors have further found that these ink
compositions have various excellent properties, for example,
ejection stability, required of ink compositions for ink jet
recording. The present invention has been made based on such
finding.
[0012] Accordingly, it is an object of the present invention to
provide an ink composition which has various excellent properties,
especially an ink composition which can yield prints having
excellent drying properties and has excellent storage stability,
and can realize images having no significant feathering or bleeding
on various recording media, particularly on plain papers and
recycled papers.
[0013] It is another object of the prevent invention to provide an
ink composition having various excellent properties, for example,
ejection stability, required of ink compositions for ink jet
recording.
[0014] According to one aspect of the present invention, there is
provided an ink composition comprising at least a colorant, water,
and a compound represented by formula (I).
RO[EO.paren close-st..sub.nPO.paren close-st..sub.m]M (I)
[0015] wherein
[0016] R represents a group represented by formula; 1
[0017] R.sup.1 represents an alkyl, cycloalkyl, or aryl group;
[0018] EO represents an ethyleneoxy group;
[0019] PO represents a propyleneoxy group;
[0020] m and n each are independently 0 (zero) or a natural number
of not less than 1, provided that m+n>1;
[0021] EO and PO may be arranged, regardless of order in the
parentheses of formula (I), randomly or as blocks joined
together;
[0022] R.sup.2 and R.sup.3 each independently represent a hydrogen
atom or an alkyl group; and
[0023] M is a group attached to the terminal oxygen atom within the
parentheses.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Ink composition
[0025] The ink composition according to the present invention may
be used in recording methods using an ink composition. Recording
methods using an ink composition include, for example, an ink jet
recording method, a recording method using writing utensils, such
as pens, and other various recording methods. In particular, the
ink composition according to the present invention is preferably
used in an ink jet recording method.
[0026] Compound represented by formula (I)
[0027] In formula (I), R represents a group represented by formula
(II), and the total number of carbon atoms of R is preferably 4 to
50, more preferably 4 to 30, from the viewpoint of the penetration
of the ink composition and the solubility of the compound
represented by formula (I) in water. When the total number of
carbon atoms of R exceeds 30, the hydrophobicity of the compound is
enhanced. Therefore, in some cases, the number of ethyleneoxy
groups or propyleneoxy groups may be increased to ensure the water
solubility of the compound. Further, according to finding of the
present inventors, a compound, wherein the total number of carbon
atoms of R exceeds 30, is likely to cause foaming. Therefore, when
such a compound is used, care may be taken so as to avoid the
occurrence of the unfavorable foaming phenomenon.
[0028] In formula (II), R.sup.1 represents an alkyl group
(preferably C.sub.3-20 alkyl, more preferably C.sub.5-10 alkyl), a
cycloalkyl group (preferably C.sub.3-20 cycloalkyl, more preferably
C.sub.5-10 cycloalkyl), an aryl group (preferably phenyl, naphtyl,
biphenyl, tolyl, xylyl, or cumyl).
[0029] In formula (I), EO represents an ethyleneoxy group, PO
represents a propyleneoxy group, and n and m each indenpendently
are a number of 0 (zero) or 1 or more.
[0030] In the present invention, the compound represented by
formula (I) is a single compound selected from the group consisting
of compounds represented by formula (I), or alternatively is a
mixture of at least two compounds selected from the group
consisting of compounds represented by formula (I). When the single
compound is used as the compound represented by formula (I), this
single compound may be obtained by separation from a mixture of two
or more compounds represented by formula (I) by distillation or
other conventional process.
[0031] According to a preferred embodiment of the present
invention, when m in formula (I) is 0 (zero), n is preferably 1 to
10. On the other hand, when m is not 0, n is preferably 0 to 10
with m being 1 to 5.
[0032] EO and PO may be arranged, regardless of order in the
parentheses of formula (I), randomly or as blocks joined together.
In the compound represented by formula (I) , when n and m are not
simultaneously 0, a compound having a structure, wherein PO has
been added to an organic group represented by formula (II) followed
by the addition of EO, is preferred from the viewpoint of print
quality.
[0033] R.sup.2 and R.sup.3 each independently represent a hydrogen
atom or an alkyl group, preferably an alkyl group having 1 to 6
carbon atoms.
[0034] M represents a group attached to the terminal oxygen atom
within the parentheses. According to a preferred embodiment of the
present invention, M in formula (I) is preferably selected from
[0035] (i) a hydrogen atom,
[0036] (ii) an alkali metal, an inorganic base, or an organic base,
or
[0037] (iii) a residue of an acid selected from the group
consisting of sulfonic acid, phosphoric acid, and boric acid, or a
salt of said acid with said compound (ii).
[0038] Preferred examples of M include (a) a hydrogen atom, (b)
lithium, sodium, and potassium as alkali metals, (c) ammonia as the
inorganic base, and (d) organic amines as the organic base.
Specific examples of organic amines include mono-, di-, or
tri-(hydroxy-C.sub.1-6 alkyl)amine, for example, monoethanolamine,
diethanolamine, triethanolamine, monoisopropanolamine, and
mono-s-butanolamine.
[0039] When M or the counter ion contained in M is one which is
liberated in the ink, all the ion species of the compound
represented by formula (I) contained in the ink composition are
preferably identical.
[0040] The compound represented by formula (I) is preferably
synthesized by the following method:
[0041] (a) a method wherein a target molar amount of ethylene oxide
or propylene oxide is added in the presence of an alkali or the
like to an alcohol represented by formula R--OH, wherein R is as
defined above, is used as a starting compound, to form the compound
represented by formula (I), or
[0042] (b) a method wherein a mono- or poly-ethylene glycol or a
mono- or poly-propylene glycol is subjected to
dehydro-addition.
[0043] The compound represented by formula (I), which has been
produced by the above method, is generally in the form of a mixture
of a plurality of compounds wherein n and m are different from each
other. As described above, this mixture as such can be added to the
ink composition, or alternatively can be optionally isolated into a
single kind of compound.
[0044] Commercially available products may be utilized as the
alcohol represented by formula R--OH. Specific examples thereof
include; Surfynol 61 which is an alcohol represented by R--OH
wherein R.sup.1 represents an isobutyl group, R.sup.2 represents a
methyl group, and R.sup.3 represents a hydrogen atom; Olfine B
which is an alcohol represented by R--OH wherein R.sup.1 and
R.sup.2 each represent a methyl group and R.sup.3 represents a
hydrogen atom; and Olfine P which is an alcohol represented by
R--OH wherein R.sup.1 represents an ethyl group, R.sup.2 represents
a methyl group, and R.sup.3 represents a hydrogen atom (all the
above products being available from Nissin Chemical Industry Co.,
Ltd).
[0045] Preferably, the alcohol used in the production of the
compound represented by formula (I) does not remain in the product.
The amount of the residual alcohol, if any, is preferably not more
than 1% by weight. This is because, when the amount of the residual
alcohol is not more than 1% by weight, it is possible to
effectively avoid problems including high susceptibility to wetting
of the head in its nozzle face to cause the formation of prints
having deteriorated quality, and the emission of the odor of
alcohol
[0046] In the present invention, the average molecular weight of
the compound represented by formula (I) is preferably not more than
2000, more preferably not more than 1000, still more preferably not
more than 500.
[0047] Preferably, the ink composition according to the present
invention further comprises a penetrating agent selected from the
group consisting of propylene glycol monobutyl ether, dipropylene
glycol monobutyl ether, and mixtures thereof. Although the ink
composition for ink jet recording according to the present
invention has excellent penetrability, these penetrating agents can
further improve the penetration effect. The amount of the
penetrating agent added is preferably not more than 10% by weight,
more preferably 0.5 to 5% by weight. The weight ratio of the
compound represented by formula (I) to the penetrating agent is
preferably 1:0 to 1:10.
[0048] According to a preferred embodiment of the present
invention, the ink composition according to the present invention
further comprises an acetylene glycol surfactant. The addition of
the acetylene glycol surfactant can further improve the print
quality. The amount of the acetylene glycol surfactant added is
preferably not more than 5% by weight, more preferably 0.1 to 2% by
weight, from the viewpoints of the effect improved by the addition
of the acetylene glycol surfactant and the prevention of an
increase in viscosity.
[0049] According to a preferred embodiment of the present
invention, the weight ratio of the compound represented by formula
(I) to the acetylene glycol surfactant is 1:0 to 1:3.
[0050] Examples of preferred acetylene glycol surfactants include
compounds represented by formula 2
[0051] wherein 0.ltoreq.m*+n*.ltoreq.50; and R.sup.1*, R.sup.2*,
R.sup.3*, and R.sup.4* each independently represent an alkyl group,
preferably a C.sub.1-6 alkyl group.
[0052] Commercially available products may be used as the compound
represented by the above formula, and examples thereof include
Olfine Y and Surfynol 82. Surfynol 440, Surfynol 465, and Surfynol
485 (all the above products being manufactured by Air Products and
Chemicals Inc.). They may be used alone or in combination of two or
more.
[0053] According to a preferred embodiment of the present
invention, when the acetylene glycol surfactant is used, diethylene
glycol monobutyl ether or triethylene glycol monobutyl ether is
added in combination with the acetylene glycol surfactant from the
viewpoint of improving the solubility. The amount of the acetylene
glycol surfactant added is preferably not more than 20% by weight
from the viewpoint of properly maintaining the viscosity of the ink
composition. The weight ratio of the compound represented by
formula (I) to diethylene glycol monobutyl ether or triethylene
glycol monobutyl ether is preferably 1:0 to 1:10.
[0054] According to the present invention, the colorant may be
properly selected from dyes or pigments. If necessary, the dye and
the pigment may be properly used in combination.
[0055] According to the present invention, various dyes commonly
used in ink jet recording, such as direct dyes, acid dyes,
foodstuff dyes, basic dyes, reactive dyes, disperse dyes, vat dyes,
and soluble vat dyes, may be used as the dye. Further, colorants,
which fall into categories of oil soluble dyes and basic dyes, may
also be used.
[0056] Various pigments, for example, inorganic or organic
pigments, may be used as the pigment. Specific examples thereof
include:
[0057] (a) pigments for black, for example, carbon blacks (C.I.
Pigment Black 7), such as furnace black, lamp black, acetylene
black, and channel black, metal oxides, such as copper oxide, iron
oxide (C.I. Pigment Black 11), and titanium oxide, and organic
pigments, such as aniline black (C.I. Pigment Black 1);
[0058] (b) pigments for yellow, for example, C.I. Pigment Yellow 1
(Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 24, 34, 35,
37, 42 (yellow iron oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR),
95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, and
153;
[0059] (c) pigments for magenta, for example, C.I. Pigment Red 1,
2, 3, 5, 17, 22 (Brilliant Fast Scarlet), 23, 31, 38, 48:2
(Permanent Red 2B (Ba)), 48:2 (Permanent Red 2B (Ca)), 48:3
(Permanent Red 2B (Sr)), 48;4 (Permanent Red 2B (Mn)), 49:1, 52:2,
53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81
(Rhodamine 6G Lake), 83, 88, 101 (iron oxide red), 104, 105, 106,
108 (cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146,
149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 202, 209,
and 219; and
[0060] (d) pigments for cyan, for example, C.I. Pigment Blue 1, 2,
15 (Phthalocyanine Blue R), 15:1, 15:2, 15:3 (Phthalocyanine Blue
G). 15:4, 15:6 (Phthalocyanine Blue E), 16, 17:1, 56, 60, and 63,
and C.I. Pigment Green 1, 4, 7, 8, 10, 17, 18, and 36, Further,
predispersed pigments, such as grafted carbons, produced by
treating the surface of pigments, for example, with resin may also
be used.
[0061] According to the present invention, the particle diameter of
the pigment is preferably not more than 25 .mu.m, more preferably
not more than 1 .mu.m, still more preferably not more than 0.1
.mu.m.
[0062] According to a preferred embodiment of the present
invention, the pigment is preferably one which can be dispersed in
the ink composition with the aid of a dispersant or a surfactant,
or a surface treated pigment which has on its surface a dispersion
group and can be dispersible in an aqueous medium without the aid
of any dispersant.
[0063] In the ink composition according to the present invention,
the dispersant, which may be used in dispersing the pigment in the
ink, is preferably a resin dispersant wherein the molecular
skeleton is constituted by a styrene/acrylic acid copolymer resin,
the weight average molecular weight (hereinafter referred to simply
as "molecular weight") is 1,600 to 25,000 and the acid value is 100
to 250. Specific examples of such dispersants include those
manufactured by Johnson Polymer Corp., for example, Joncryl 68
(molecular weight 10,000, acid value 195), Joncryl 680 (molecular
weight 3,900, acid value 215), Joncryl 682 (molecular weight 1,600,
acid value 235), Joncryl 550 (molecular weight 7,500, acid value
200). Joncryl 555 (molecular weight 5,000, acid value 200), Joncryl
586 (molecular weight 3,100, acid value 105), Joncryl 683
(molecular weight 7,300, acid value 150), and B-36 (molecular
weight 6,800, acid value 250).
[0064] In order to dissolve the resin dispersant, the residue of
acrylic acid in the resin dispersant is preferably in the form of a
salt. Neutralizers usable for the formation of the salt include,
for example, aminomethylpropanol, 2-aminoisopropanol,
triethanolamine. morpholine, and ammonia. The addition of the
neutralizer in an amount of at least the neutralization equivalent
of the dispersant suffices for contemplated results. The amount of
the neutralizer added, however, is preferably about 1.3 times the
neutralization equivalent from the viewpoint of the fixation after
printing.
[0065] Further, pH buffer is preferably added to facilitate ion
dissociation of the salt in the dispersant, thereby regulating the
ink to an optimal pH value. Specific examples of pH buffers usable
herein include potassium hydrogenphthalate, potassium
dihydrogenphosphate, disodium hydrogenphosphate, sodium
tetraborate, potassium hydrogentartrate, sodium hydrogencarbonate,
sodium carbonate, tris(hydroxymethyl)aminomethane, and
tris(hydroxymethyl)aminomethane hydrochloride. From the viewpoint
of the durability of the head member and the stability of the ink,
the amount of the pH buffer added is preferably such that the pH
value of the ink composition is brought to about 7 to 10.
[0066] In the present invention, the dispersion group in "the
surface treated pigment which has on its surface a dispersion group
and can be dispersible in an aqueous medium without the aid of any
dispersant" refers to a group which can render the pigment
dispersible by itself, that is, without the addition of any
dispersant in an aqueous medium. Specific examples of dispersion
groups include carboxyl, carbonyl, hydroxyl, and sulfonic acid
groups.
[0067] The introduction of the dispersion group into the surface of
the pigment may be properly carried out according to the type of
the dispersion group. For example, carboxyl or hydroxyl groups can
be introduced by oxidation. The oxidation refers to a method
wherein the pigment is oxidized in a liquid phase or gaseous phase
with an oxidizing agent, for example, ozone, nitric acid, hydrogen
peroxide, hypohalous acid, nitrogen oxide, or fluorine gas. Plasma
treatment of the surface of the pigment also can introduce carboxyl
or hydroxyl groups into the surface of the pigment. On the other
hand, when sulfonic acid groups are introduced as the dispersion
group, the sulfonic acid groups can be introduced by sulfonation.
The sulfonation refers to treatment with a sulfonating agent, such
as sulfuric acid, fuming nitric acid, sulfonated
pyridine-carboxylic acid, sulfamic acid, sulfur trioxide,
chlorosulfuric acid, or amidosulfuric acid. These oxidizing agents
and sulfonating agents may be used alone or as a mixture of two or
more.
[0068] The surface treated pigment is also stable against glycol
ethers, for example, (di)propylene glycol monobutyl ether and
di(tri)ethylene glycol monobutyl ether which are used as a surface
tension modifier. This is advantageous over the dispersion of the
pigment with the aid of a dispersant in that the pigment can be
stably stored and used under high temperature or low temperature
conditions.
[0069] According to the present invention, the content of the
colorant is preferably 0.5 to 30% by weight, more preferably 1 to
12% by weight, based on the ink composition from the viewpoint of
ensuring the print density and preventing a deterioration in
ejection stability due to an increase in viscosity.
[0070] If necessary, the ink composition according to the present
invention may further contain optional ingredients, such as
water-soluble organic solvents, preservatives, fungicides,
antioxidants, electric conductivity adjustors, pH adjustors,
viscosity modifiers, other surface tension modifiers, and oxygen
absorbers, These optional ingredients may be used solely or as a
mixture of a plurality of optional ingredients falling within the
same category or a plurality of optional ingredients selected from
different categories.
[0071] For example, water-soluble glycols or saccharides may be
used to prevent the ink composition from being dried at the front
face of nozzles in the recording head.
[0072] Examples of water-soluble glycols usable herein include
ethylene glycol, diethylene glycol, triethylene glycol, propylene
glycol, dipropylene glycol, tripropylene glycol, polyethylene
glycol having a butanediol, 1,3-butanediol, 1,2-pentanediol,
5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2,6-hexanetriol,
1,8-octanediol, 1,2-octanediol, glycerin, mesoerythritol, and
pentaerythritol.
[0073] Saccharides usable herein include monosaccharides and
polysaccharides. More specific examples thereof include glucose,
mannose, fructose, ribose, xylose, arabinose, lactose, galactose,
aldonic acid, glucitose, maltose, cellobiose, sucrose, trehalose,
maltotriose, alginic acid and salts thereof, cyclodextrins, and
celluloses. The amount of the saccharide added to the ink
composition is preferably 0.05 to 30% by weight from the viewpoints
of restoring the front end of the head, clogged with the ink as
result of drying of the ink, to its original condition, that is, to
unclogged state, and preventing an increase in viscosity of the
ink. The amount of the monosaccharide and the polysaccharide, such
as glucose, mannose, fructose, ribose, xylose, arabinose, lactose,
galactose, aldonic acid, glucitose, maltose, cellobiose, sucrose,
trehalose, or maltotriose, is more preferably 3 to 20% by weight.
The amount of alginic acid and salts thereof, cyclodextrins, and
celluloses added is preferably such that the addition of these
compounds does not excessively increase the viscosity of the
ink.
[0074] The ink composition according to the present invention may
further contain the following compounds: alkyl alcohols having 1 to
4 carbon atoms; glycol ethers, such as ethylene glycol monomethyl
ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl
ether, ethylene glycol monomethyl ether acetate, diethylene glycol
monomethyl ether, diethylene glycol monoethyl ether, diethylene
glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether,
diethylene glycol mono-iso-propyl ether, ethylene glycol
mono-n-butyl ether, diethylene glycol mono-n-butyl ether,
triethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl
ether, diethylene glycol mono-t-butyl ether,
1-methyl-1-methoxybutanol, propylene glycol monomethyl ether,
propylene glycol monoethyl ether, propylene glycol mono-t-butyl
ether, propylene glycol mono-n-propyl ether, propylene glycol
mono-iso-propyl ether, dipropylene glycol monomethyl ether,
dipropylene glycol monoethyl ether, dipropylene glycol
mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether,
propylene glycol mono-n-butyl ether, and dipropylene glycol
mono-n-butyl ether; formamide; acetamide; dimethyl sulfoxide
sorbit; sorbitan; acetin; diacetin; triacetin; and sulfolane. These
compounds are compatible with water, and can improve the solubility
of glycol ethers, which have low solubility in water, contained in
the ink composition and the ink ingredients, and, in addition, can
improve the penetration of the ink composition into recording
media, for example, paper, or can prevent nozzle clogging.
[0075] The ink composition according to the present invention may
further comprise other surfactant from the viewpoint of regulating
the penetration of the ink composition into recording media, or
regulating the surface tension of the ink composition. The
surfactant is preferably highly compatible with the ink composition
according to the present invention. Further, the surfactant
preferably has high penetration and is highly stable. Such
surfactants include, for example, amphoteric surfactants and
nonionic surfactants.
[0076] Specific examples of amphoteric surfactants include
lauryldimethylaminoacetic acid betaine,
2-alkyl-N-carboxymethyl-N-hydroxy- ethylimidazolinium betaine,
coconut oil fatty acid amide propyldimethylaminoacetic acid
betaine, polyoctylpolyaminoethylglycine, and imidazoline
derivatives.
[0077] Specific examples of nonionic surfactants usable 3
[0078] herein include ether surfactants, such as polyoxyethylene
nonylphenyl ether, polyoxyethylene octylphenyl ether,
polyoxyethylene dodecylphenyl ether, polyoxyethylene alkylallyl
ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether,
polyoxyethylene alkyl ether, and polyoxyalkylene alkyl ether,
polyoxyethyleneoleic acid, ester surfactants, such as
polyoxyethyleneoleic ester, polyoxyethylenedistearic ester,
sorbitan laurate, sorbitan monostearate, sorbitan monooleate,
sorbitan sesquioleate, polyoxyethylene monooleate, and
polyoxyethylene stearate, and fluorosurfactants, such as
fluoroalkyl esters and salts of perfluoroalkylcarboxylic acid.
[0079] For example, sodium benzoate, pentachloroprenol sodium,
2-pyridinethiol-1-oxide sodium, sodium sorbate, sodium
dehydroacetate, and 1,2-dibenzothiazolin-3-one (Proxel CRL, Proxel
BDN, Proxel GXL, Proxel XL-2, and Proxel TN, manufactured by ICI)
may be used as preservatives or fungicides in the ink composition
of the present invention.
[0080] pH adjustors, solubilizers, or antioxidants usable herein
include: amines, for example, alkanolamines, such as
diethanolamine, triethanolamine, and propanolane,
alkylalkanolamines, such as methyldiethanolamine,
dimethylethanolamine, ethyldiethanolamine, and diethylethanolamine,
and morpholine, and modification products thereof; inorganic salts,
such as potassium hydroxide, sodium hydroxide, and lithium
hydroxide; ammonium hydroxide; quaternary ammonium hydroxide, such
as tetramethylammonium; salts of carbonic acid, such as potassium
carbonate, sodium carbonate, and lithium carbonate; salts of
phosphoric acid, such as potassium phosphate, sodium phosphate, and
lithium phosphate; N-methyl-2-pyrrolidone; urea compounds, such as
urea, thiourea, and tetramethylurea; allophanates, such as
allophanate and methyl allophanate; biurets, such as biuret,
dimethylbiuret, and tetramethylbiuret; and L-polyvinyl alcohol,
hydroxypropylcellulose, carboxymethylcellulose,
hydroxyethylcellulose, methylcellulose, salts of polyacrylic acid,
polyvinylpyrrolidone, gum arabic, and starch.
[0081] When the ink composition according to the present invention
is used in ink jet recording, various additives are preferably
added to the ink, for example, from the viewpoints of ensuring
stability under standing conditions, and realizing stable ejection
from an ink ejection head.
[0082] Further, commercially available antioxidants and ultraviolet
absorbers may also be used, and examples thereof include: Tinuvin
328, 900, 1130, 384, 292, 123, 144, 622, 770, and 292, Irgacor 252
and 153, and Irganox 1010, 1076, 1035, and MD 1024, manufactured by
Ciba-Geigy; and lanthanide oxides.
EXAMPLES
[0083] The present invention will be described in more detail with
reference to the following examples, though it is not limited to
these examples only.
[0084] Pigment dispersion 1
[0085] A styrene/acrylic acid copolymer resin (weight average
molecular weight 25,000, acid value 200) (4 parts by weight), 2.7
parts by weight of triethanolamine, and 0.4 part by weight of
isopropyl alcohol, were fully dissolved in 72.9 parts by weight of
ion-exchanged water with heating at 70.degree. C. Carbon Black
MA-100 (manufactured by Mitsubishi Chemical Corporation) (20 parts
by weight) was then added to the solution. After premixing,
dispersion was carried out by means of Eiger Mill (manufactured by
Eiger Japan) to an average particle diameter of the pigment of 100
nm (percentage beads packing=70%, media diameter=0.7 nm) to prepare
a contemplated pigment dispersion. The pigment dispersion was
diluted, and the diluted pigment dispersion was measured for the
average diameter of dispersed particles by a laser scattering
method and found to be 105 nm.
[0086] Pigment dispersion 2
[0087] A pigment dispersion 2 was prepared in the same manner as in
the pigment dispersion 1, except that copper phthalocyanine was
used instead of carbon black. The pigment dispersion 2 thus
obtained had an average diameter of dispersed particles of 85
nm.
[0088] Pigment dispersion 3
[0089] The surface of carbon black was oxidized with nitric acid to
introduce mainly a modification group terminated with carbonyl and
carboxyl groups into the surface of the carbon black to prepare a
self-dispersible carbon black as a pigment dispersion 3. The
pigment dispersion 3 thus obtained had an average diameter of
dispersed particles of 90 nm.
[0090] Pigment dispersion 4
[0091] The surface of carbon black was oxidized with sulfuric acid
to introduce mainly a modification group terminated with sulfone
groups into the surface of the carbon black to prepare a
self-dispersible carbon black as a pigment dispersion 4. The
pigment dispersion 4 thus obtained had an average diameter of
dispersed particles of 85 nm.
[0092] The following abbreviations are used in the following
description.
[0093] DEGmBE: diethylene glycol monobutyl ether,
[0094] TEGmBE: triethylene glycol monobutyl ether,
[0095] PGmBE: propylene glycol monobutyl ether,
[0096] DPGmBE: dipropylene glycol monobutyl ether, and
[0097] DEGmME: diethylene glycol monomethyl ether.
[0098] In the following examples, 0.1 to 1% by weight of Proxel
XL-2, 0.001 to 0.05% by weight of benzotriazole, and 0.01 to 0.03%
by weight of EDTA were added to water as the balance.
1 Example A1 (wt %) Pigment dispersion 1 5.0 (solid basis) Compound
A1 3.0 DEGmBE 2.0 Glycerin 6.0 1,5-Pentanediol 5.0 Triethanolamine
0.8 Ion-exchanged water Balance
[0099] The compound A1 is a compound represented by formula (I)
wherein R has the structure of Surfynol 61, n is 2.0, m is 0
(zero). and M represents sodium.
2 Example A2 (wt %) Pigment dispersion 2 4.5 (solid basis) Compound
A2 5.0 PGmBE 2.0 Dipropylene glycol 5.0 Surfynol 465 1.2
Triethanolamine 0.9 Ion-exchanged water Balance
[0100] The compound A2 is a compound represented by formula (I)
wherein R has the structure of Olfine B, n is 3.0, m is 0 (zero),
and M represents --N(C.sub.2H.sub.4OH).sub.3.
3 Example A3 (wt %) Pigment dispersion 3 5.5 (solid basis) Compound
A3 2.0 DPGmBE 1.5 Diethylene glycol 7.0 Thiodiglycol 3.5
1,6-Hexanedial 5.0 Triethanolamine 1.0 Potassium hydroxide 0.1
[0101] 4
[0102] is 4.0, m is 0 (zero), and M represents a hydrogen atom.
4 Example A4 (wt %) Pigment dispersion 4 5.0 (solid basis) C.I.
Direct Black 154 1.0 Compound A4 1.0 ThGmBE 3.0 Diethylene glycol
3.0 1,5-Pentanediol 20 Dimethyl-2- 2.0 imidazolidinone Sodium
benzoate 0.1 Triethanolamine 0.7 Ion-exchanged water Balance
[0103] The compound A4 is a compound represented by formula (I)
wherein R has the structure of Surfynol 61, n is 3.0, m is 0
(zero). and M represents --NH.sub.4.
5 Example A5 (wt %) Pigment dispersion 1 3.0 (solid basis) C.I.
Direct Black 154 1.0 Compound A5 as 7.0 mixture DEGmBE 2.0 Glycerin
14.0 Triethanolamine 0.9 Ion-exchanged water Balance
[0104] The compound A5 is a mixture composed of; 50% by weight of a
compound represented by formula (I) wherein R has the structure of
Surfynol 61, n is 4.0, m is 0 (zero), and M represents potassium;
and 50% by weight of a compound represented by formula (I) wherein
R has the structure of Olfine P, n is 2.0, m is 0 (zero), and M
represents potassium.
6 Example A6 (wt %) C.I. Direct Yellow 132 5.0 Compound A6 4.0
TEGmBE 4.0 Thiodiglycol 2.0 1,5-Pentanediol 1.0 Triethanolamine 0.9
Ion-exchanged water Balance
[0105] The compound A6 is a compound represented by formula (I)
wherein R has the structure of Surfynol 61, provided that R.sup.3
represents C.sub.2H.sub.5--, n is 7.0, m is 0 (zero), and M
represents lithium.
7 Example A7 (wt %) C.I. Direct Blue 86 5.0 Compound A7 as 10.0
mixture DEGmBE 3.0 Glycerin 5.0 Trimethylolpropane 1.0
Trimethylolethane 1.0 Surfynol 465 1.0 Triethanolamine 0.5
Potassium hydroxide 0.05 Ion-exchanged water Balance
[0106] The compound A7 is a mixture composed of: 50% by weight of a
compound represented by formula (I) wherein R has the structure of
Surfynol 61, n is 1, m is 0 (zero), and M represents --BO.sub.3Na;
and 50% by weight of a compound represented by formula (I) wherein
R has the structure of Olfine B, n is 1, m is 0 (zero), and M
represents --SO.sub.3K.
8 Example A8 (wt %) C.I. Acid Red 52 5.5 Compound A8 as 1.5 mixture
Glycerin 5.0 Diethylene glycol 5.0 Tetrapropylene glycol 5.0
Triethanolamine 0.9 Potassium hydroxide 0.1
[0107] The compound A8 is a mixture composed of: 50% by weight of a
compound represented by formula (I) wherein R has the structure of
Olfine B, n is 10, m is 0 (zero), and M represents potassium, 30%
by weight of a compound represented by formula (I) wherein R has
the structure of Olfine P, n is 2.5, m is 0 (zero), and M
represents --NH.sub.4; and 20% by weight of a compound represented
by formula (I) wherein R has the structure of Surfynol 61, n is
3.0, m is 0 (zero), and M represents sodium.
9 Example B1 (wt %) Pigment dispersion 1 5.0 (solid basis) Compound
B1 5.0 DEGmBE 2.0 Glycerin 6.0 1,5-Pentanediol 5.0 Triethanolamine
0.8 Ion-exchanged water Balance
[0108] The compound B1 is a compound represented by formula (I)
wherein R has the structure of Surfynol 61, n is 1.0, m is 1.5, and
M represents sodium.
10 Example B2 (wt %) Pigment dispersion 2 4.5 (solid basis)
Compound B2 5.0 PGmBE 2.0 Dipropylene glycol 5.0 Surfynol 465 1.2
Triethanolamine 0.9 Ion-exchanged water Balance
[0109] The compound B2 is a compound represented by formula (I)
wherein R has the structure of Olfine B, n is 1.0, m is 2.0, and M
represents --N(C.sub.2H.sub.4OH).sub.3.
11 EXAMPLE B3 (wt %) Pigment dispersion 3 5.5 (solid basis)
Compound B3 5.0 DPGmBE 1.5 Diethylene glycol 7.0 Thiodiglycol 3.5
1,6-Hexanediol 5.0 Triethanolamine 1.0 Potassium hydroxide 0.1
Ion-exchanged water Balance
[0110] The compound B3 is a compound represented by formula (I)
wherein R has the structure of Olfine P, n is 0 (zero), m is 4.5,
and M represents a hydrogen atom.
12 EXAMPLE B4 (wt %) Pigment dispersion 4 5.0 (solid basis) C.I.
Direct Black 154 1.0 Compound B4 8.0 TEGmBE 3.0 Diethylene glycol
3.0 1,5-Pentanediol 2.0 Dimethyl-2-imidazolidinone 2.0 Sodium
benzoate 0.1 Triethanolamine 0.7 Ion-exchanged water Balance
[0111] The compound B4 is a compound represented by formula (I)
wherein R has the structure of Surfynol 61, n is 3.0, m is 1.0, and
M represents --NH.sub.4.
13 EXAMPLE B5 (wt %) Pigment dispersion 1 3.0 (solid basis) C.I.
Direct Black 154 1.0 Compound B5 as mixture 7.0 DEGmBE 2.0 Glycerin
14.0 Triethanolamine 0.9 Ion-exchanged water Balance
[0112] The compound B5 is a mixture composed of: 50% by R has the
structure of Surfynol 61, n is 4.0, m is 1.0, and M represents
potassium; and 50% by weight of a compound represented by formula
(I) wherein R has the structure of Olfine P, n is 2.0, m is 1.0,
and M represents potassium.
14 EXAMPLE B6 (wt %) C.I. Direct Yellow 132 5.0 Compound B6 6.0
TEGmBE 4.0 Glycerin 15.0 Thiodiglycol 2.0 1,5-Pentanediol 1.0
Triethanolamine 0.9 Ion-exchanged water Balance
[0113] The compound B6 is a compound represented by formula (I)
wherein R has the structure of Surfynol 61, provided that R.sup.3
represents an ethyl group, n is 7.0, m is 1.0, and M represents
lithium.
15 EXAMPLE B7 (wt %) C.I. Direct Blue 86 5.0 Compound B7 as mixture
10.0 DEGmBE 3.0 Glycerin 5.0 Trimethylolpropane 1.0
Trimethylolethane 1.0 Surfynol 465 1.0 Triethanolamine 0.5
Potassium hydroxide 0.05 Ion-exchanged water Balance
[0114] The compound B7 is a mixture composed of; 50% by weight of a
compound represented by formula (I) wherein R has the structure of
Surfynol 61, n is 0 (zero), m is represents --SO.sub.4K.
16 EXAMPLE B8 (wt %) C.I. Acid Red 52 5.5 Compound B8 as mixture
6.0 Glycerin 5.0 Diethylene glycol 5.0 Tetrapropylene glycol 5.0
Triethanolamine 0.9 Potassium hydroxide 0.1 Ion-exchanged water
Balance
[0115] The compound B8 is a mixture composed of: 50% by weight of a
compound represented by formula (I) wherein R has the structure of
Olfine B, n is 0 (zero), m is 1.0, and M represents potassium; 30%
by weight of a compound represented by formula (I) wherein R has
the structure of Olfine P, n is 2.5, m is 1.5, and M represents
--NH.sub.4; and 20% by weight of a compound represented by formula
(I) wherein R has the structure of Surfynol 61, n is 3.0, m is 1.5,
and M represents sodium.
17 COMPARATIVE EXAMPLE 1 (wt %) Pigment dispersion 1 5.0 (solid
basis) Glycerin 10.0 Dispersant: 3.0 Hitenol N-07 (manufactured by
Dai-Ichi Kogyo Seiyaku Co., Ltd.) Nonionic surfactant: 1.0 Noigen
EA 160 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
Ion-exchanged water Balance
[0116]
18 COMPARATIVE EXAMPLE 2 (wt %) C.I. Direct Yellow 132 5.5 DEGmME
7.0 Diethylene glycol 10.0 2-Pyrrolidone 5.0 Ion-exchanged water
Balance
[0117]
19 COMPARATIVE EXAMPLE 3 (wt %) Pigment dispersion 3 5.5 (solid
basis) C.I. Direct Black 154 2.5 Diethylene glycol 10.0 Nonionic
surfactant: 1.0 Epan 450 (manufactured by Dai-ichi Kogyo Seiyaku
Co., Ltd.) Ion-exchanged water Balance
[0118] Evaluation 1:
[0119] The ink compositions thus obtained, were bidirectionally
printed as a plurality of character line patterns having different
sizes on the following predetermined test papers. The prints thus
obtained were visually inspected for blurring of characters and
feathering of characters due to ink migration down paper fibers to
evaluate print quality.
[0120] The printing was performed by means of an ink jet printer
EM-900C under conditions of 360 dpi and fine mode for plain paper.
In this evaluation test, plain papers commercially available in
Europe, America, and Japan, specifically Conqueror (manufactured by
Arjo Wiggins), Favorit (manufactured by XEROGRAFIE), Modo Copy
(manufactured by Modo), Rapid Copy (manufactured by igepa), EPSON
EPP (manufactured by Seiko Epson Corporation), Xerox P
(manufactured by Xerox Corp.), Xerox 4024 (manufactured by Xerox
Corp.), Xerox 10 (manufactured by Xerox Corp.), Neenha Bond
(manufactured by Kimberly-Clark), Ricopy 6200 (manufactured by
Ricoh Co., Ltd.), Yamayuri (manufactured by Honshu Paper Co.,
Ltd.), and Xerox R (manufactured by Xerox Corp.), were used as test
papers.
[0121] The results were evaluated according to the following
criteria:
[0122] A: A Japanese Kanji character "" in a JIS Minchou form at a
size of 3 mm square could be printed without overlapping.
[0123] B: A Japanese Kanji character "" in a JIS Minchou form at a
size of 4 mm square could be printed without overlapping.
[0124] C: Overlapping was observed in a printed Japanese Kanji
character "" in a JIS Minchou form at a size of 4 mm square.
[0125] D: Overlapping was observed in a printed Japanese Kanji
character "" in a JIS Minchou form at a size of 5 mm square.
[0126] The results were as summarized in Table 2.
20 TABLE 1 Example A 1 2 3 4 5 6 7 8 Conqueror A A A A A A A A
Favorit A A A A A A A A Modo Copy A A A A A A A A Rapid Copy A A A
A A A A A EPSON EPP A A A A A A A A Xerox P A A A A A A A A Xerox
4024 A A A A A A A A Xerox 10 A A A A A A A A Neenha Bond A A A A A
A A A Ricopy 6200 A A A A A A A A Yamayuri A A A A A A A A Xerox R
A A A A A A A A
[0127]
21 TABLE 2 Comparative Example B Example 1 2 3 4 5 6 7 8 1 2 3
Conqueror A A A A A A A A C C C Favorit A A A A A A A A D D D Modo
Copy A A A A A A A A C D D Rapid Copy A A A A A A A A D D D EPSON
EPP A A A A A A A A C C C Xerox P A A A A A A A A C C D Xerox 4024
A A A A A A A A D D D Xerox 10 A A A A A A A A C D D Neenha Bond A
A A A A A A A C D D Ricopy 6200 A A A A A A A A D C D Yamayuri A A
A A A A A A D D D Xerox R A A A A A A A A D D D
[0128] Evaluation 2:
[0129] The inks of Examples A1 to A8 and B1 to B8 were placed in
sample bottles made of glass. These glass bottles were hermetically
sealed, and were then allowed to stand at 60.degree. C. for one
week. Before and after the standing, the inks were inspected for
sediment and were measured for property values (viscosity and
surface tension).
[0130] As a result, for all the inks, sediment did not
substantially occur, and there was substantially no change in
property values between before and after the standing. Thus, all
the inks had good storage stability.
* * * * *