U.S. patent application number 15/353034 was filed with the patent office on 2017-03-09 for ink composition, ink set, and black ink set.
The applicant listed for this patent is Seiko Epson Corporation. Invention is credited to Tomoyuki OKUYAMA.
Application Number | 20170066939 15/353034 |
Document ID | / |
Family ID | 53797528 |
Filed Date | 2017-03-09 |
United States Patent
Application |
20170066939 |
Kind Code |
A1 |
OKUYAMA; Tomoyuki |
March 9, 2017 |
INK COMPOSITION, INK SET, AND BLACK INK SET
Abstract
Disclosed herein is an ink composition, including: a pigment;
acetylenediol having an HLB of less than 4; and an anionic
surfactant, in which the mass ratio of the acetylene diol to the
anionic surfactant is 0.30 to 4.0.
Inventors: |
OKUYAMA; Tomoyuki; (Chino,
JP) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Seiko Epson Corporation |
Tokyo |
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JP |
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|
Family ID: |
53797528 |
Appl. No.: |
15/353034 |
Filed: |
November 16, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14624957 |
Feb 18, 2015 |
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15353034 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B41J 2/16505 20130101;
C09D 11/40 20130101; C09D 11/38 20130101; C09D 11/324 20130101;
C09D 175/04 20130101 |
International
Class: |
C09D 11/324 20060101
C09D011/324; B41J 2/165 20060101 B41J002/165; C09D 175/04 20060101
C09D175/04; C09D 11/38 20060101 C09D011/38; C09D 11/40 20060101
C09D011/40 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 2014 |
JP |
2014-030361 |
Claims
1. An aqueous ink composition configured for use in an ink jet
recording apparatus having a nozzle for ejecting the ink
composition and a suction cap that defines a cap space that
includes an ink absorber therein, the suction cap being configured
to seal the nozzle for evacuating the cap space, the ink
composition comprising: a pigment, a content of the pigment being
equal to or greater than 5.0 mass %; acetylenediol having an HLB of
less than 4, a content of the acetylenediol being 0.010 mass % to
0.40 mass %; a 1,2-alkanediol having 4 to 6 carbon atoms, a content
of the 1,2-alkanediol having 4 to 6 carbon atoms being 0.50 mass %
to 6.0 mass %; and an anionic surfactant, a content of the anionic
surfactant being 0.025 mass % to 0.25 mass %, wherein the
solubility of the acetylenediol having an HLB of less than 4 in
water being improved by the anionic surfactant, a mass ratio of the
acetylenediol to the anionic surfactant is 0.30 to 4.0, and a mass
ratio of the acetylenediol to the 1,2-alkanediol is 0.0010 to
0.100.
2. The ink composition according to claim 1, wherein the
acetylenediol includes
2,5,8,11-tetramethyl-6-dodecyne-5,8-diol.
3. The ink composition according to claim 1, wherein the anionic
surfactant contains at least one selected from the group consisting
of polyoxyethylene-based compounds and sulfates.
4. The ink composition according to claim 1, wherein the content of
the pigment is 5.0 mass % to 10 mass %.
5. The ink composition according to claim 1, further comprising an
acetylenediol derivative having an HLB of equal to or greater than
7.
6. The ink composition according to claim 1, further comprising a
pyrrolidone derivative, a content of the pyrrolidone derivative
being 1.0 mass % to 12 mass %.
7. The ink composition according to claim 1, wherein a dissolved
nitrogen content is equal to or greater than 10 ppm.
8. The ink composition according to claim 1, wherein the pigment
contains self-dispersing carbon black.
9. An ink set, comprising: a self-dispersing black ink, which is
the ink composition according to claim 8; and a color ink.
10. A black ink set, comprising: a self-dispersing black ink, which
is the ink composition according to claim 8; and a resin-dispersing
black ink containing resin-dispersing carbon black and
acetylenediol having an HLB of less than 4, wherein the content of
the acetylenediol contained in the resin-dispersing black ink is
lower than the content of the acetylenediol contained in the
self-dispersing black ink, and the content of the resin-dispersing
carbon black is equal to or less than 3.0 mass %.
11. An ink jet recording apparatus, comprising: the ink composition
according to claim 1; a nozzle for ejecting the ink composition;
and a suction cap that seals the nozzle, the suction cap defining a
cap space that includes an ink absorber therein, and the cap space
configured to be evacuated when the suction cap seals the
nozzle.
12. An ink jet recording apparatus, comprising: the ink composition
according to claim 2; a nozzle for ejecting the ink composition;
and a suction cap that seals the nozzle, the suction cap defining a
cap space that includes an ink absorber therein, and the cap space
configured to be evacuated when the suction cap seals the
nozzle.
13. An ink jet recording apparatus, comprising: the ink composition
according to claim 3; a nozzle for ejecting the ink composition;
and a suction cap that seals the nozzle, the suction cap defining a
cap space that includes an ink absorber therein, and the cap space
configured to be evacuated when the suction cap seals the
nozzle.
14. The ink composition according to claim 5, wherein the
acetylenediol derivative having an HLB of equal to or greater than
7 is selected from the group consisting of an alkylene oxide adduct
of 2,5,8,11-tetramethyl-6-decyne-5,8-diol,
2,4-dimethyl-5-decyne-4-ol, and an alkylene oxide adduct of
2,4-dimethyl-5-decyne-4-ol.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/624,957, filed Feb. 18, 2015, which claims
priority to Japanese Patent Application No. 2014-030361, filed Feb.
20, 2014, the disclosures of both applications are expressly
incorporated by reference herein in their entireties.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to an ink composition, an ink
set, and a black ink set.
[0004] 2. Related Art
[0005] As a liquid ejecting apparatus for ejecting liquid onto a
target, an ink jet printer for ejecting ink onto a recording medium
(hereinafter, simply referred to as a printer) is known. In this
printer, in order to reduce the ejection failure of ink, cleaning
for discharging the ink or the like thickened from an injection
nozzle for ejecting ink has been appropriately carried out.
[0006] In this cleaning, a nozzle formation surface provided with
nozzles is sealed with a suction cap, and then a space (in the
suction cap) hermetically closed with the nozzle formation surface
and the suction cap is vacuumed up by a suction pump. That is, in
the cleaning, a space having negative pressure is formed in the
discharge direction of ink, and the thickened ink or like is
discharged from a nozzle by using the negative pressure.
[0007] In such cleaning, generally, the ink discharged from the
nozzle is sucked by the suction pump through the suction cap, and
is then discharged to an ink recovery unit as a liquid recovery
unit. In such an ink recovery unit, an ink absorber for absorbing
ink is contained. This ink absorber absorbs the discharged ink,
thereby recovering the ink discharged from the suction pump.
[0008] As an example of the technology focusing on an ink recovery
unit, JP-A-2006-21451 is known. JP-A-2006-21451, for the purpose of
providing a liquid absorber for eliminating the bubbles contained
in the liquid discharged from an outlet of a suction pump to a
liquid recovery unit and smoothly absorbing and recovering the
discharged liquid, discloses a liquid absorber for absorbing the
liquid discharged from an outlet of a suction means depressurizing
the space by suctioning liquid and gas, in which the liquid
absorber includes a defoaming agent for eliminating the bubbles
contained in the liquid discharged from the outlet.
[0009] However, in the technique described in JPA-2006-21451, there
is a problem that a mechanism for supplying a defoaming agent to
the liquid absorber of the liquid recovery unit in a recording
apparatus is further required.
[0010] Further, the ink sucked through the nozzle contains the
bubbles generated therein by the suction (negative pressure).
Through the suction cap, fine bubbles are discharged together with
the thickened ink. Since it is difficult for these bubbles to be
absorbed by the ink absorber in the suction cap, an ink composition
accumulates in the suction cap, and eventually the ink composition
overflows from the suction cap. When the ink composition overflows
from the suction cap, there is a concern that the nozzle formation
surface is contaminated during the cleaning, and thus
cleaning-induced ejection failure occurs.
SUMMARY
[0011] An advantage of some aspects of the invention is to provide
an ink composition, an ink set, and a black ink set, each of which
can suppress cleaning-induced ejection failure and is excellent in
intermittent characteristics.
[0012] The present inventors have conducted intensive studies. As a
result, they have found that the invention can be realized by using
a predetermined acetylenediol and an anionic surfactant, thus
completing the invention.
[0013] That is, the invention is as follows.
[0014] [1] According to an aspect of the invention, there is
provided an ink composition, including: a pigment; acetylenediol
having an HLB of less than 4; and an anionic surfactant, in which
the mass ratio of the acetylenediol to the anionic surfactant is
0.30 to 4.0.
[0015] [2] The ink composition according to the above [1] may
further include 1,2-alkanediol having 4 to 6 carbon atoms, in which
the mass ratio of the acetylenediol to the 1,2-alkanediol may be
0.0010 to 0.100.
[0016] [3] In the ink composition according to the above [1] or
[2], the acetylenediol may include
2,5,8,11-tetramethyl-6-dodecyne-5,8-diol.
[0017] [4] In the ink composition according to any one of the above
[1] to [3], the content of the anionic surfactant may be 0.025 mass
% to 0.25 mass %.
[0018] [5] In the ink composition according to any one of the above
[1] to [4], the content of the acetylenediol may be 0.010 mass % to
0.40 mass %.
[0019] [6] In the ink composition according to any one of the above
[1] to [5], the anionic surfactant may contain at least one
selected from the group consisting of polyoxyethylene-based
compounds and sulfates.
[0020] [7] In the ink composition according to any one of the above
[1] to [6], the content of the pigment may be equal to or greater
than 5.0 mass %.
[0021] [8] The ink composition according to any one of the above
[1] to [7] may be used in a recording apparatus having a suction
cap.
[0022] [9] The ink composition according to any one of the above
[1] to [8] may further include an acetylenediol derivative having
an HLB of equal to or greater than 7.
[0023] [10] The ink composition according to any one of the above
[1] to [9] may further include a pyrrolidone derivative.
[0024] [11] The ink composition according to any one of the above
[1] to [10] may have a dissolved nitrogen content of equal to or
greater than 10 ppm.
[0025] [12] In the ink composition according to any one of the
above [1] to [11], the pigment may contain self-dispersing carbon
black.
[0026] [13] According to another aspect of the invention, there is
provided an ink set, including: a self-dispersing black ink, which
is the ink composition according to the above [12]; and a color
ink.
[0027] [14] According to still another aspect of the invention,
there is provided a black ink set, including: a self-dispersing
black ink, which is the ink composition according to the above
[12]; and a resin-dispersing black ink containing resin-dispersing
carbon black and acetylenediol having an HLB of less than 4, in
which the content of the acetylenediol contained in the
resin-dispersing black ink is lower than the content of the
acetylenediol contained in the self-dispersing black ink, and in
which the content of the resin-dispersing carbon black is equal to
or less than 3.0 mass %.
[0028] [15] According to still another aspect of the invention,
there is provided a recording apparatus, including the ink
composition according to any one of the above [1] to [12], the ink
set according to the above [13], or the black ink set according to
the above [14].
BRIEF DESCRIPTION OF THE DRAWING
[0029] The invention will be described with reference to the
accompanying drawing, wherein like numbers reference like
elements.
[0030] FIGURE is a schematic view of a suction cap provided in a
recording apparatus.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0031] Hereinafter, an embodiment of the invention (hereinafter,
referred to as "present embodiment") will be described in detail
with reference to the drawing as necessary, but the invention is
not limited thereto. Various modifications can be made within the
scope not departing from the gist thereof. In the drawing, the same
elements are given the same reference numerals and the description
thereof will not be repeated. In addition, the positional
relationships such as top, bottom, left, and right are based on the
positional relationships shown in the drawing unless otherwise
specified. Furthermore, the ratios of the dimensions are not
limited to the ratios shown in the drawings.
Ink Composition
[0032] The ink composition according to the present embodiment
includes: a pigment; acetylenediol having an HLB of less than 4;
and an anionic surfactant, in which the mass ratio of the
acetylenediol to the anionic surfactant is 0.30 to 4.0.
Pigment
[0033] Carbon black used in a black ink is not particularly
limited, but examples thereof include No. 2300, No. 900, MCF88, No.
33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B, and the
like (all are manufactured by Mitsubishi Chemical Corporation);
Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven
700, and the like (all are manufactured by Carbon Columbia Co.,
Ltd.); Regal 400R, Regal 330R, Regal 660R, Mogul L, Monarch 700,
Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100,
Monarch 1300, Monarch 1400, and the like (all are manufactured by
CABOT JAPAN K.K.); and Color Black FW1, Color Black FW2, Color
Black FW2V, Color Black FW18, Color Black FW200, Color Black S150,
Color Black S160, Color Black S170, Printex 35, Printex U, Printex
V, Printex 140U, Special Black 6, Special Black 5, Special Black
4A, Special Black 4, and the like (all are manufactured by Degussa
Co., Ltd.).
[0034] The pigment used in a black ink is not particularly limited,
but specific examples thereof include self-dispersing carbon black
and resin-dispersing carbon black. Among these, self-dispersing
carbon black is preferable. Since the self-dispersing carbon black
tends to easily contain nitrogen, increase the dissolved nitrogen
content of the ink composition and easily generates bubbles, the
invention is particularly advantageous.
[0035] The pigment used in a white ink is not particularly limited,
but examples thereof include C.I. Pigment Whites 6, 18, and 21,
titanium oxide, zinc oxide, zinc sulfide, antimony oxide, zirconium
oxide, white hollow resin particles, and polymer particles.
[0036] The pigment used in a yellow ink is not particularly
limited, but examples thereof include C.I. Pigment Yellows 1, 2, 3,
4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65,
73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113,
114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154,
167, 172, and 180.
[0037] The pigment used in a magenta ink is not particularly
limited, but examples thereof include C.I. Pigment Reds 1, 2, 3, 4,
5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30,
31, 32, 37, 38, 40, 41, 42, 48:2, 48:5, 57:1, 88, 112, 114, 122,
123, 144, 146, 149, 150, 166, 168, 170, 171, 175, 176, 177, 178,
179, 184, 185, 187, 202, 209, 219, 224, and 245; and C.I. Pigment
Violets 19, 23, 32, 33, 36, 38, 43, and 50.
[0038] The pigment used in a cyan ink is not particularly limited,
but examples thereof include C.I. Pigment Blues 1, 2, 3, 15, 15:1,
15:2, 15:3, 15:34, 15:4, 16, 18, 22, 25, 60, 65, and 66; and C. I.
Bat Blues 4 and 60.
[0039] Other pigments except for the above-mentioned pigments are
not particularly limited, but examples thereof include C.I. Pigment
Greens 7 and 10; C.I. Pigment Browns 3, 5, 25, and 26; and C.I.
Pigment Oranges 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43,
and 63.
[0040] Pigments may be used alone or in a combination of two or
more thereof.
[0041] The above-mentioned pigment may be a dispersible pigment.
Examples of methods of dispersing the pigment include a method of
dispersing the pigment using a water-soluble resin, a method of
dispersing the pigment using a surfactant, and a method of
dispersing the pigment by chemically and physically providing a
hydrophilic functional group to the surface of a pigment particle
to enable the pigment particles to be dispersed and/or dissolved.
In the pigment used in the present embodiment, any one of the
above-mentioned methods may be used, and, if necessary, a
combination thereof may also be used. Particularly, in the method
of dispersing the pigment in an aqueous ink composition using a
water-soluble resin, when aqueous ink recorded matter adheres to a
recording medium, the adhesion between the recording medium and the
aqueous ink composition and/or the adhesion between solidified
products in the aqueous ink composition can be increased, and
therefore, this method is preferable. In addition, the method of
dispersing the pigment in an aqueous ink composition by chemically
and physically providing a hydrophilic functional group to the
surface of a pigment particle is preferred in terms of improving
the dispersion stability of the pigment and making the preservation
stability of this aqueous ink composition better.
[0042] The content of the pigment is preferably 5.0 mass % to 10
mass %, more preferably 5.0 mass % to 9.0 mass %, and still more
preferably 5.0 mass % to 8.0 mass %, based on the total amount of
the ink composition. When the content of the pigment is equal to or
greater than 5.0 mass %, there is a tendency to further improve an
OD value. In addition, when the content of the pigment is equal to
or less than 10 mass %, there is a tendency to further improve
discharge stability and setting reliability.
Acetylenediol Having HLB of Less than 4
[0043] When the ink composition according to the present embodiment
includes acetylenediol having an HLB of less than 4, the
defoamability of the ink composition is further improved, thereby
suppressing the cleaning-induced ejection failure thereof. In the
invention, HLB is defined by the following Equation through the
Griffin method. The lower limit of HLB is not particularly limited,
but equal to or greater than 0 is preferable.
HLB value=20.times.sum of formula weight of hydrophilic
portion/molecular weight
[0044] The acetylenediol having an HLB of less than 4 is not
particularly limited, but an example thereof includes
2,5,8,11-tetramethyl-6-dodecyne-5,8-diol. When this acetylenediol
having an HLB of less than 4 is used, there is a tendency to
further improve the defoamability of the ink composition, thereby
suppressing the cleaning-induced ejection failure thereof. The
acetylenediol having an HLB of less than 4 may be used alone or in
a combination of two or more. The ink composition according to the
present embodiment does not include
2,4,7,9-tetramethyl-5-decyne-4,7-diol having an HLB equal to or
greater than 4 (commercially available product: Surfynol 104) or
the like.
[0045] The content of the acetylenediol having an HLB of less than
4 is preferably 0.010 mass % to 0.40 mass %, more preferably 0.012
mass % to 0.30 mass %, and still more preferably 0.014 mass % to
0.20 mass %, based on the total amount of the ink composition. When
the content of the acetylenediol having an HLB of less than 4 is
equal to or greater than 0.01 mass %, there is a tendency to
further suppress cleaning-induced ejection failure. In addition,
when the content of the acetylenediol having an HLB of less than 4
is equal to or less than 0.40 mass %, there is a tendency to
further improve intermittent characteristics.
Acetylenediol Derivative Having HLB of 7 or More
[0046] It is preferable that the ink composition according to the
present embodiment include an acetylenediol derivative having an
HLB of 7 or more. When the ink composition includes an
acetylenediol derivative having an HLB of 7 or more, there is a
tendency to further improve discharge stability. The acetylenediol
derivative having an HLB of 7 or more is not particularly limited,
but examples thereof include an alkylene oxide adduct of
2,4,7,9-tetramethyl-5-decyne-4,7-diol, an alkylene oxide adduct of
2,5,8,11-tetramethyl-6-decyne-5,8-diol, 2,4-dimethyl-5-decyne-4-ol,
and an alkylene oxide adduct of 2,4-dimethyl-5-decyne-4-ol.
Commercially available products of the acetylenediol derivative
having a HLB of 7 or more are not particularly limited, but
examples thereof include Olfine E1010 and Surfynol 465.
[0047] The content of the acetylenediol derivative having an HLB of
7 or more is preferably 0.10 mass % to 1.5 mass %, more preferably
0.15 mass % to 1.0 mass %, and still more preferably 0.25 mass % to
0.75 mass %, based on the total amount of the ink composition. When
the content of the acetylenediol derivative having an HLB of 7 or
more is equal to or greater than 0.10 mass %, there is a tendency
to further improve discharge stability. In addition, when the
content of the acetylenediol derivative having an HLB of 7 or more
is equal to or less than 1.5 mass %, there is a tendency to further
improve setting reliability.
[0048] From the viewpoint of improvement of solubility of the
acetylenediol having an HLB of less than 4, preferably, the content
of the acetylenediol derivative having an HLB of equal to or
greater than 7 exceeds the content of the acetylenediol having an
HLB of less than 4, and more preferably, the content of the
acetylenediol derivative having an HLB of equal to or greater than
7 is two times or more than the content of the acetylenediol having
an HLB of less than 4.
Anionic Surfactant
[0049] Relatively hydrophobic acetylenediol having a HLB of less
than 4 tends to gather in the meniscus with the evaporation of
moisture from a nozzle and thus thicken the ink in the vicinity of
a nozzle opening. For this reason, the intermittent characteristics
of an ink composition containing acetylenediol having a HLB of less
than 4 are apt to decrease. However, since the ink composition
according to the present embodiment includes an anionic surfactant,
it is possible to improve the solubility of acetylenediol having a
HLB of less than 4 in water, and thus it is possible to alleviate
the increase in the viscosity of ink, thereby exhibiting excellent
intermittent characteristics.
[0050] The anionic surfactant is not particularly limited, but
examples thereof include alkyl sulfocarboxylate, .alpha.-olefin
sulfonate, polyoxyethylene alkyl ether acetates, N-acylamino acid
and salts thereof, N-acylmethyltaurine salt, alkyl sulfate,
polyoxyalkyl ether sulfate, polyoxyethylene alkyl ether phosphate,
rosin acid soap, castor oil sulfate, lauryl alcohol sulfate,
alkylphenol type phosphate ester, alkyl type phosphate ester,
alkylaryl sulfonate, diethyl sulfosuccinate, diethyl hexyl
sulfosuccinate, and dioctyl sulfosuccinate. Among these, at least
one selected from the group consisting of polyoxyethylene compounds
and sulfates is preferable. The polyoxyethylene compounds are not
particularly limited, but examples thereof include polyoxyethylene
alkyl ether acetates, and polyoxyethylene alkyl ether phosphates
such as polyoxyethylene lauryl ether phosphate and the like. The
sulfates are not particularly limited, but examples thereof include
alkyl sulfates such as sodium lauryl sulfate and the like, and
polyoxyethylene alkyl ether sulfates. When such anionic surfactant
is used, there is a tendency to improve intermittent
characteristics. In addition, as the anionic surfactant, an anion
type surfactant, which is a resin, may be used. The anionic
surfactant may be used alone or in a combination of two or
more.
[0051] The content of the anionic surfactant is preferably 0.025
mass % to 0.25 mass %, more preferably 0.030 mass % to 0.20 mass %,
and still more preferably 0.050 mass % to 0.20 mass %, based on the
total amount of the ink composition. When the content of the
anionic surfactant is equal to or greater than 0.025 mass %, there
is a tendency to further improve intermittent characteristics. In
addition, when the content of the anionic surfactant is equal to or
less than 0.25 mass %, there is a tendency to further reduce
foamability.
[0052] The mass ratio of acetylenediol to the anionic surfactant
(when the mass of the anionic surfactant is set to 1) is 0.30 to
4.0, preferably 0.50 to 3.5, and more preferably 0.60 to 3.0. When
the mass ratio of acetylenediol to the anionic surfactant is equal
to or greater than 0.30, cleaning-induced ejection failure can be
further suppressed. In addition, when the mass ratio of
acetylenediol to the anionic surfactant is equal to or less than
4.0, intermittent characteristics are further improved.
1,2-alkanediol having 4 to 6 carbon atoms
[0053] It is preferred that the ink composition according to the
present embodiment further include 1,2-alkanediol having 4 to 6
carbon atoms. When this ink composition further includes
1,2-alkanediol having 4 to 6 carbon atoms, there is a tendency to
further improve discharge stability. The 1,2-alkanediol having 4 to
6 carbon atoms is not particularly limited, but examples thereof
include 1,2-butanediol, 1,2-pentanediol, and 1,2-hexanediol.
[0054] The content of the 1,2-alkanediol having 4 to 6 carbon atoms
is preferably 0.50 mass % to 6.0 mass %, more preferably 1.0 mass %
to 5.0 mass %, and still more preferably 2.0 mass % to 4.0 mass %,
based on the total amount of the ink composition. When the content
of the 1,2-alkanediol having 4 to 6 carbon atoms is equal to or
greater than 0.50 mass %, there is a tendency to further improve
discharge stability. In addition, when the content of the
1,2-alkanediol having 4 to 6 carbon atoms is equal to or less than
6.0 mass %, there is a tendency to further improve setting
reliability.
[0055] The mass ratio of acetylenediol to the 1,2-alkanediol (when
the mass of the 1,2-alkanediol is set to 1) is preferably 0.0010 to
0.100, more preferably 0.0025 to 0.075, and still more preferably
0.0050 to 0.050. When the mass ratio of acetylenediol to the
1,2-alkanediol is equal to or greater than 0.0010, there is a
tendency to further improve defoamability. In addition, when the
mass ratio of acetylenediol to the 1,2-alkanediol is equal to or
less than 0.100, it is possible to secure solubility.
Pyrrolidone Derivative
[0056] It is preferred that the ink composition according to the
present embodiment further include a pyrrolidone derivative. When
this ink composition further includes a pyrrolidone derivative,
there is a tendency to further improve intermittent ability. The
pyrrolidone derivative is not particularly limited, but examples
thereof include 2-pyrrolidone, N-methyl-2-pyrrolidone, and
N-ethyl-2-pyrrolidone.
[0057] The content of the pyrrolidone derivative is preferably 1.0
mass % to 12 mass %, more preferably 2.0 mass % to 10 mass %, and
still more preferably 4.0 mass % to 8.0 mass %, based on the total
amount of the ink composition. When the content of the pyrrolidone
derivative is equal to or greater than 1.0 mass %, there is a
tendency to further improve intermittency. In addition, when the
content of the pyrrolidone derivative is equal to or less than 12
mass %, there is a tendency to further improve setting reliability.
Resin
[0058] It is preferred that the ink composition according to the
present embodiment further include a resin. As the resin, for
example, a resin, in which a polymer component is dispersed or
dissolved in a solvent in the form of an emulsion, is preferable.
Among these, the resin, in which a polymer component is dispersed
or dissolved in a solvent in the form of an emulsion, is
preferable. When such resin is used, there is a tendency that
recorded matter having more excellent water resistance and abrasion
resistance is obtained.
[0059] The resin is not particularly limited, but examples thereof
include an acrylate resin, a vinyl acetate resin, a vinyl chloride
resin, a butadiene resin, a styrene resin, a polyester resin, a
crosslinked acrylate resin, a crosslinked styrene resin, a
benzoguanamine resin, a phenol resin, a silicone resin, an epoxy
resin, a urethane resin, a paraffin resin, a fluorocarbon resin, a
water-soluble resin, and a copolymer, which is a combination of
monomers constituting these resins. The copolymer is not
particularly limited, but examples thereof include a
styrene-butadiene resin and a styrene-acrylate resin. In addition,
as the resin, a polymer latex containing these resins may be used.
For example, the polymer latex is a polymer latex containing the
microparticles of an acrylate resin, styrene-acrylate resin,
styrene resin, crosslinked acrylate resin, and crosslinked styrene
resin.
[0060] Among these, an acrylate resin, a urethane resin, a
polyester resin, a water-soluble resin, and a copolymer, which is a
combination of monomers constituting these resins, are preferable.
These resins tend to further improve the abrasion resistance of the
obtained recorded matter. These resins may be used alone or in a
combination of two or more thereof.
[0061] The content of the resin is preferably 0.5 mass % to 5.0
mass %, more preferably 0.5 mass % to 4.0 mass %, and still more
preferably 0.5 mass % to 3.0 mass %, based on the total amount of
the ink composition. When the content of the resin is more than or
equal to 0.5 mass %, there is a tendency to further improve the
fixing property to media. In addition, when the content of the
resin is equal to or less than 5.0 mass %, there is a tendency to
further improve setting reliability.
Other Components
[0062] In the ink composition according to the present embodiment,
in order to favorably maintain the storage stability and the
discharge stability from the head, to improve the clogging, and to
prevent the deterioration of the ink composition, various
additives, such as a dissolution aid, a viscosity modifier, a pH
adjuster, an antioxidant, a preservative, an anti-mold agent, a
corrosion inhibitor, and a chelating agent for capturing a metal
ion that influences dispersion, may be added appropriately.
Dissolved Nitrogen Content
[0063] In the content of dissolved nitrogen in an ink composition,
generally, with the decrease of the dissolved nitrogen content, the
generation of bubbles is suppressed, and cleaning-induced ejection
failure is suppressed. However, in order to keep the dissolved
nitrogen content of the ink composition at a low level, a degassing
mechanism is required in the production step and the storage step.
In the ink composition according to the present embodiment, even
when the dissolved nitrogen content thereof is set to equal to or
greater than 10 ppm or equal to or greater than 15 ppm, bubbles are
hardly generated by the defoaming effect of the acetylenediol
having a HLB of less than 4, and thus the cleaning-induced ejection
failure tends to be suppressed. Meanwhile, the upper limit of the
dissolved nitrogen content is not particularly limited, but is
preferably equal to or less than 50 ppm, and more preferably equal
to or less than 25 ppm. This dissolved nitrogen content may be
measured by the methods described in the following Examples.
Ink Composition for Recording Apparatus Having Suction Cap
[0064] It is preferable that the ink composition according to the
present embodiment be used for a recording apparatus having a
suction cap. In the case where a recording apparatus having a
suction cap is used, when an ink composition prone to generate
bubbles is used, the discharged ink composition is easily
accumulated in the suction cap, and particularly, cleaning-induced
ejection failure easily occurs. Therefore, the present invention is
particularly advantageous. Hereinafter, the suction cap will be
described with reference to FIGURE.
[0065] FIGURE is a schematic view of a suction cap provided in a
recording apparatus. As shown in FIGURE, a round bar-shaped guide
shaft 16 is installed in a longitudinal direction. The guide shaft
16 is provided with a carriage 17 which is movably inserted and
supported along the longitudinal direction. This carriage 17 is
configured to reciprocate in a horizontal direction (main scanning
direction X) along the guide shaft 16 by the driving force of a
carriage motor (not shown).
[0066] Below the carriage 17, a platen 18 is disposed in parallel
to the guide shaft 16. The platen 18 is a support base which is
disposed to oppose the carriage 17 to support a recording paper P
fed from a paper feeding unit. This platen 18 is provided with a
paper feeding mechanism (not shown) for feeding the recording paper
P in a direction (sub-scanning direction Y) perpendicular to the
main scanning direction X.
[0067] The carriage 17 is provided with a recording head 19. The
recording head 19 is provided with a nozzle formation surface 19a.
The nozzle formation surface 19a is provided with a plurality of
liquid ejecting nozzles (not shown) for ejecting ink as a
liquid.
[0068] A suction cap 26 is formed in the shape of an upper
side-opening box, and is reciprocally supported along a vertical
direction by a lifting mechanism (not shown). The suction cap 26 is
provided at the bottom surface thereof with a suction hole 26a
penetrating the suction cap 26 in the vertical direction. Further,
the suction cap 26 is provided at the inside thereof with a
sheet-shaped discharge ink absorber 26b. Furthermore, the suction
cap 26 is provided at the upper edge thereof with a rectangular
outer frame 26c made of a flexible member.
[0069] And, when the recording head 19 moves to an non-printing
area and the suction cap 26 moves upward, the outer frame 26c of
the suction cap 26 comes in contact with the recording head 19 I to
seal the nozzle formation surface 19a. Thus, a space sealing the
nozzle formation surface 19a, that is, a cap space is formed in the
suction cap 26.
[0070] The suction hole 26a formed at the bottom of the suction cap
26 is connected to a discharge tube 27. The discharge tube 27 is a
flow channel for air or ink, and is configured to allow the
communication between an ink recovery unit 30 and the cap space
through a suction pump 28. This suction pump 28 is a pump that is
operated by a pump motor (not shown). When the suction pump 28
operates, the gas in the cap space is sucked, a negative pressure
corresponding to the suction capacity of the suction pump 28 is
formed. By this negative pressure, the thickened ink or the like in
the recording head 19 is ejected from the liquid ejecting nozzles
toward the cap space (discharge ink absorber 26b). This ejected ink
or the like is discharged to the ink recovery unit 30 together with
the gas in the cap space through the suction pump 28 and the
discharge tube 27.
[0071] As such, in this cleaning mechanism 25, By setting the
inside of the suction cap 26 to the negative pressure, the
thickened ink or the like is ejected from the liquid ejecting
nozzles, thus cleaning the inside of the recording head 19.
Simultaneously, in this cleaning mechanism 25, the ejected ink or
the like is sucked in the suction pump 28, and is thus discharged
to the ink recovery unit 30.
Ink Set
[0072] The ink set according to the present embodiment includes:
the above-described ink composition (hereinafter, referred to as
"self-dispersing black ink") containing self-dispersing carbon
black; and a color ink. Since carbon black contained in the
self-dispersing black ink tends to easily contain nitrogen and
easily increase the dissolved nitrogen content causing
cleaning-induced discharge failure, the invention is particularly
advantageous. Generally, in terms of suppressing the bleeding of
black ink into color ink on recorded matter, it is preferred that
the wettability of black ink be low, that is, the content of a
surfactant be small. Even in this regard, it is preferred that the
ink composition of the present embodiment, which can suppress
cleaning-induced ejection failure and improve intermittent
characteristics by containing a relative small amount of an anionic
surfactant, be used as black ink.
[0073] The "color ink" is not particularly limited if it is an ink
composition containing a color pigment, and commonly known color
inks may be used. The color ink may contain acetylenediol have a
HLB of less than 4. The surfactant contained in the color ink is
not particularly limited, but examples thereof include a
silicone-based surfactant and a fluorine-based surfactant.
[0074] The method of manufacturing a self-dispersing black ink is
not particularly limited, but, for example, there is a method of
mixing water with ingredients other than a pigment, a resin and
acetylenediol and then additionally mixing this obtained mixture
with a pigment, a resin and acetylenediol.
Black Ink Set
[0075] The black ink set according to the present embodiment
includes: a self-dispersing black ink, which is the above-described
ink composition; and a resin-dispersing black ink containing
resin-dispersing carbon black and acetylenediol having a HLB of
less than 4. Here, the content of acetylenediol contained in the
resin-dispersing black ink is less than the content of the
acetylenediol contained in the self-dispersing black ink, and the
content of the resin-dispersing carbon black is less than or equal
to 3.0 mass %.
[0076] The black ink set including the self-dispersion black ink
and the resin-dispersing black ink has the following effects.
First, the self-dispersing black ink can provide higher black
density to matte paper. This is because a small amount of resin
exists between carbon particles and this is finely fixed on matte
paper. Meanwhile, the resin-dispersing black ink can provide high
black density and high glossiness to glossy paper. This is because
the dispersed resin swollen with an organic solvent such as
1,2-hexanediol smoothly covers the surface of fixed pigment, and
thus gloss appears. By the above effects, if the black ink set of
the present embodiment is used, it is possible to obtain a
high-quality recorded matter for extensive recording media.
[0077] The resin-dispersing carbon black and acetylenediol having a
HLB of less than 4 contained in the resin-dispersing black ink are
the same as above.
[0078] The content of the acetylenediol having a HLB of less than 4
contained in the resin-dispersing black ink is less than the
content of the acetylenediol having a HLB of less than 4 contained
in the self-dispersing black ink. Specifically, the content of the
acetylenediol having a HLB of less than 4 contained in the
resin-dispersing black ink is preferably 0.0015 mass % to 0.0075
mass %, more preferably 0.0020 mass % to 0.0070 mass %, and still
more preferably 0.0025 mass % to 0.0065 mass %. When the content of
the acetylenediol having a HLB of less than 4 contained in the
resin-dispersing black ink is less than the content of the
acetylenediol having a HLB of less than 4 contained in the
self-dispersing black ink, there are following effects. Since the
resin-dispersing black ink tends to contain a relatively small
amount of pigment, to be different from the self-dispersing black
ink and to have a small dissolved nitrogen content, the
acetylenediol having a HLB of less than 4 may be contained in a
small amount. In addition, since this acetylenediol has strong
hydrophobicity, there are risks of separating it from a liquid
medium and it attacking resin (dispersant), it is preferred that
its content be small.
[0079] The content of the resin-dispersing carbon black is
preferably equal to or less than 3.0 mass %, and more preferably
equal to or less than 2.75 mass %, based on the total amount of the
resin-dispersing black ink. The lower limit of the content of the
resin-dispersing carbon black is not particularly limited, but is
preferably equal to or greater than 0.50 mass %. When the content
of the resin-dispersing carbon black is equal to or less than 3.0
mass %, there is a tendency to further improve setting
reliability.
Recording Apparatus
[0080] The recording apparatus according to the present embodiment
of the invention is an apparatus for recording an image using the
above-described ink composition or ink set. The recording apparatus
according to the present embodiment includes a suction cap, and it
is preferable that this suction cap be used in the above-described
ink composition or cleaning.
[0081] The printing methods of the recording apparatus include
various printing methods, such as offset printing, flexographic
printing, gravure printing, ink jet printing, and the like. Among
these, an ink jet recording apparatus using an ink jet printing
method is preferable. As the ejecting method of ink jet ink,
commonly known ejecting methods may be used, and, particularly,
when a method of ejecting liquid droplets using the vibration of a
piezoelectric element (a recording method using an ink jet head
that forms ink droplets by the mechanical deformation of an
electrostrictive element) is used, it is possible to perform an
excellent image recording.
Examples
[0082] Hereinafter, the invention will be described in more detail
with reference to the following Examples and Comparative Examples.
The invention is not limited to these Examples.
Materials for Ink Composition
[0083] Main materials of the ink composition used in the following
Examples and Comparative Examples are as follows.
Pigment
[0084] Self-dispersing carbon black Resin-dispersing carbon
black
Resin-dispersing PB 15:3
Resin-dispersing PY74
Resin-dispersing PV19
Solvent
Glycerin
[0085] 2-pyrrolidone 1,2-hexanediol Dipropylene glycol
Acetylenediol derivative Olfine E1010 (HLB=13, manufactured by
Nissin Chemical Industry Co., Ltd.)
Acetylenediol
[0086] Compound A (2,5,8,11-tetramethyl-6-dodecyne-5,8-diol, HLB=3)
Silicone-based surfactant BYK348 (manufactured by BASF Corporation)
Anionic surfactant Polyoxyethylene oleyl ether sodium sulfate
(product name: LATEMUL WX, manufactured by Kao Chemicals Co., Ltd.)
Sodium lauryl sulfate (product name: EMAL 10G, manufactured by Kao
Chemicals Co., Ltd.) Polyoxyethylene lauryl ether phosphate
(product name: MP-2H, manufactured by Miyoshi oil & fat Co.,
Ltd.)
Resin
[0087] Urethane resin emulsion
Preparation of Ink Composition
[0088] The above materials were respectively mixed at the
composition ratios shown in Tables 1 and 2 below, and sufficiently
stirred to obtain to each ink composition. In Tables 1 and 2 below,
the unit of each numerical value is mass %, and the total thereof
is 100.0 mass %.
Measurement Method of Dissolved Nitrogen Content
[0089] The dissolved nitrogen content of each ink was measured by
mass conversion using gas chromatography 6890N (trade name,
manufactured by Agilent Technologies Corporation).
Surface Tension
[0090] The surface tension of each ink composition was measured at
a liquid temperature of 25.degree. C. by the Wilhelmy method using
a surface tension meter (trade name: CBVP-Z, manufactured by Kyowa
Interface Science Co., Ltd.). Unit of surface tension is
"mN/m".
Cleaning-Induced Ejection Failure Evaluation Test
[0091] PX-G930 (manufactured by Seiko Epson Corporation) was filled
with each ink composition, and cleaning was carried out using a
suction pump. Thereafter, the ink composition was ejected onto a
recording medium (product name: Superfine, manufactured by Seiko
Epson Corporation) to form a nozzle check pattern. The obtained
nozzle check pattern was visually observed to confirm the number of
nozzles that are not correctly landed, such as missing nozzles,
bent nozzle, and the like. Cleaning-induced ejection failure was
evaluated by the ratio (induction rate) of the number of nozzles
that are not correctly landed, such as missing nozzles, bent
nozzle, and the like to the total number of nozzles, based on the
following evaluation criteria.
Evaluation Criteria
[0092] A: Induction rate is less than 20%. B: Induction rate is
equal to or greater than 20% and less than 40%. C: Induction rate
is equal to or greater than 40%. Induction rate: the ratio (failure
of cleaning) of observed missing nozzle and bent nozzles in the
nozzle check pattern after cleaning.
Intermittent Characteristics Evaluation Test
[0093] The obtained ink composition was charged in a head of an ink
jet printer PX-H6000. Thereafter, a nozzle check pattern was
printed to confirm the fact that there is no filling defect and
nozzle clogging. Thereafter, the ink composition was ejected onto a
recording medium (product name: Superfine, manufactured by Seiko
Epson Corporation) to form a ruled line pattern. Thereafter, the
ejection operation was stopped for 4 seconds, and then the ink
composition was ejected onto the recording medium (product name:
Superfine, manufactured by Seiko Epson Corporation) again to form a
ruled line pattern. Intermittent characteristics were evaluated by
comparing the landing positions of the ink composition before and
after the stopping of the ejection operation, based on the
following evaluation criteria.
Evaluation Criteria
[0094] A: Ink landing position deviation is within 10 .mu.m. B: Ink
landing position deviation is greater than 10 .mu.m and equal to or
less than 40 .mu.m. C: Ink landing position deviation is greater
than 40 .mu.m and equal to or less than 150 .mu.m. D: Ink landing
position deviation is greater than 150 .mu.m, or ink is not
ejected.
TABLE-US-00001 TABLE 1 Examples 1 2 3 4 5 6 7 Pigment
Self-dispersing 6% 6% 6% 6% 6% 6% 6% carbon black Solvent Glycerin
10% 10% 10% 10% 10% 10% 10% 2-pyrrolidone 6% 6% 6% 6% 6% 6% 6%
1,2-hexanediol 3% 3% 3% 3% 3% 3% 3% Dipropylene glycol 0.03% 0.03%
0.24% 0.13% 0.13% 0.13% 0.13% Acetylenediol Olfine E1010 0.50%
0.50% 0.50% 0.50% 0.50% 0.50% 0.50% derivative (HLB = 13)
Acetylenediol Compound A 0.017% 0.017% 0.10% 0.08% 0.08% 0.13%
0.13% (HLB = 13) Anionic Polyoxyethylene 0.025% 0.05% 0.03% 0.10%
0.25% 0.05% 0.25% surfactant oleyl ether sodium sulfate Sodium
lauryl -- -- -- -- -- -- -- sulfate Polyoxyethylene -- -- -- -- --
-- -- lauryl ether phosphate Resin Urethane resin 1.00% 1.00% 1.00%
1.00% 1.00% 1.00% 1.00% emulsion Pure water balance balance balance
balance balance balance balance Ratio (acetylenediol/anionic 0.67
0.33 3.33 0.83 0.33 2.67 0.53 surfactant) Ratio
(acetylenediol/1,2-alkanediol) 0.0056 0.0056 0.0333 0.0278 0.0278
0.0444 0.0444 Dissolved nitrogen content (ppm) 20 20 20 20 20 20 20
Cleaning induction B B A A A B B Intermittent ability B B B A B B B
Examples Comparative Examples 8 9 1 2 3 4 5 Pigment Self-dispersing
6% 6% 6% 6% 6% 6% 6% carbon black Solvent Glycerin 10% 10% 10% 10%
10% 10% 10% 2-pyrrolidone 6% 6% 6% 6% 6% 6% 6% 1,2-hexanediol 3% 3%
3% 3% 3% 3% 3% Dipropylene glycol 0.13% 0.13% 0.00% 0.09% 0.13%
0.13% 0.18% Acetylenediol Olfine E1010 0.50% 0.50% 0.50% 0.50%
0.50% 0.50% 0.50% derivative (HLB = 13) Acetylenediol Compound A
0.08% 0.08% -- 0.05% 0.08% 0.08% 0.12% (HLB = 13) Anionic
Polyoxyethylene -- -- 0.10% 0.20% -- 0.30% 0.03% surfactant oleyl
ether sodium sulfate Sodium lauryl 0.10% -- -- -- -- -- -- sulfate
Polyoxyethylene -- 0.10% -- -- -- -- -- lauryl ether phosphate
Resin Urethane resin 1.00% 1.00% 1.00% 1.00% 1.00% 1.00% 1.00%
emulsion Pure water balance balance balance balance balance balance
balance Ratio (acetylenediol/anionic 0.83 0.83 0. 0.25 -- 0.27 4.8
surfactant) Ratio (acetylenediol/1,2-alkanediol) 0.0278 0.0278 --
0.0167 0.0267 0.0267 0.0400 Dissolved nitrogen content (ppm) 20 20
20 20 20 20 20 Cleaning induction A A C B A A A Intermittent
ability A A B C C C C
TABLE-US-00002 TABLE 2 Bk1 Bk2 C Y M Pigment Self-dispersing carbon
6% -- -- -- -- black Resin-dispersing carbon -- 2.1% -- -- -- black
Resin-dispersing PB -- 0.4% 5% -- -- 15:3 Resin-dispersing PY74 --
-- -- 4.0% -- Resin-dispersing PV19 -- -- -- -- 5.0% Solvent
Glycerin 10% 10% 10% 10% 10% 2-pyrrolidone 6% 6% 6% 6% 6%
1,2-hexanediol 3% 3% 3% 3% 3% Dipropylene glycol 0.13% 0.02% 0.01%
0.01% 0.01% Acetylenediol Olfine E1010 (HLB = 13) 0.50% -- -- -- --
derivative Acetylenediol Compound A (HLB = 13) 0.08% 0.01% 0.02%
0.01% 0.01% Silicone-based BYK 348 -- 0.30% 0.30% 0.80% 0.80%
surfactant Anionic Polyoxyethylene oleyl 0.10% -- -- -- --
surfactant ether sodium sulfate Resin Urethane resin 1.00% 1.00%
1.00% 1.00% 1.00% Pure water balance balance balance balance
balance Dissolved nitrogen content (ppm) 20.0 .+-. 2.0 14.0 .+-.
2.0 10.0 .+-. 2.0 10.0 .+-. 2.0 10.0 .+-. 2.0 Surface tension 29 26
28 25 25 Ratio (acetylenediol/anionic surfactant) 0.80 -- -- -- --
Ratio (acetylenediol/1,2-alkanediol) 0.0267 0.0017 0.0033 0.0033
0.0033
[0095] Ink sets including Bk1 and Bk2, Bk1 and C, Bk1 and Y, and
Bk1 and M, shown in Table 2, respectively, were prepared. The
obtained ink set was set to an ink jet printer PX-H6000.
Thereafter, a nozzle check pattern was printed to confirm the fact
that there is no filling defect and nozzle clogging. Thereafter,
the ink composition was ejected onto a recording medium. In the
case of the black ink set including Bk1 and Bk2, In the case of the
black ink set comprising Bk1 and Bk2, as the recording medium,
matte paper (product name: Superfine, manufactured by Seiko Epson
Corporation) or glossy paper (product name: Photo Paper "Glossy",
manufactured by Seiko Epson Corporation) was used. Further, in the
case of the ink sets including Bk1 and C, Bk1 and Y, and Bk1 and M,
respectively, as the recording medium, matte paper (product name:
Superfine, manufactured by Seiko Epson Corporation) was used.
Moreover, in the case of the ink sets including Bk1 and C, Bk1 and
Y, and Bk1 and M, respectively, recording was conducted such that
the boundary line of the solid pattern of Bk1 is in contact with
the boundary line of the solid pattern of C, Y, or M.
[0096] By using the black ink set including Bk1 and Bk2, when matte
paper is used as the recording medium, recorded matter having
higher black density can be obtained, and when glossy paper is used
as the recording medium, recorded matter having higher black
density and higher glossiness can be obtained.
[0097] In addition, by using the ink sets including Bk1 and C, Bk1
and Y, and Bk1 and M, respectively, cleaning-induced ejection
failure can be suppressed and intermittent characteristics can be
improved, and simultaneously the bleeding of black ink into color
ink on recorded matter can be suppressed.
* * * * *