U.S. patent application number 10/001637 was filed with the patent office on 2003-05-01 for ink-jet inks for improved image quality and reliability.
Invention is credited to Chatterjee, Amiya K., Gardner, John M., Kelly-Rowley, Anne M., Prasad, Keshava A..
Application Number | 20030079650 10/001637 |
Document ID | / |
Family ID | 21689632 |
Filed Date | 2003-05-01 |
United States Patent
Application |
20030079650 |
Kind Code |
A1 |
Prasad, Keshava A. ; et
al. |
May 1, 2003 |
Ink-jet inks for improved image quality and reliability
Abstract
The present invention provides ink-jet inks for ink-jet
printing, comprising from 0.1% to 5% by weight of at least one dye;
from 8% to 20% by weight of a diol selected from the group
consisting of 1,2-pentanediol, 1,2-hexanediol, and combinations
thereof; from 0.1% to 5% by weight of an aliphatic alcohol or
aliphatic alcohol mixture; and from 0.1% to 1.5% by weight of at
least one component independently selected from the group
consisting of buffers, biocides, and metal chelators, with the
proviso that no surfactant is present in the inkjet ink
composition. The ink-jet inks formulated according to the present
invention provide good dot size, color-to-color bleed alleviation,
improved coalescence, less chia, and improved print head materials
compatibility.
Inventors: |
Prasad, Keshava A.; (San
Marcos, CA) ; Chatterjee, Amiya K.; (San Diego,
CA) ; Gardner, John M.; (San Diego, CA) ;
Kelly-Rowley, Anne M.; (San Diego, CA) |
Correspondence
Address: |
HEWLETT-PACKARD COMPANY
Intellectual Property Administration
P.O. Box 272400
Fort Collins
CO
80527-2400
US
|
Family ID: |
21689632 |
Appl. No.: |
10/001637 |
Filed: |
October 30, 2001 |
Current U.S.
Class: |
106/31.58 |
Current CPC
Class: |
C09D 11/40 20130101;
C09D 11/30 20130101; C09D 11/32 20130101 |
Class at
Publication: |
106/31.58 |
International
Class: |
C09D 011/00 |
Claims
What is claimed is:
1. An ink-jet ink for ink-jet printing, consisting of: from 0.1% to
5% by weight of at least one dye; from 8% to 20% by weight of an
organic solvent selected from the group consisting of
1,2-pentanediol, 1,2-hexanediol, and combinations thereof; from
0.1% to 5% by weight of an aliphatic alcohol or aliphatic alcohol
mixture; from 0.1% to 1.5% by weight of at least one component
independently selected from the group consisting of buffers,
biocides, and metal chelators; and from 68.5% to 91.7% by weight of
water.
2. An ink-jet ink as in claim 1 wherein the aliphatic alcohol or
aliphatic alcohol mixture comprises alcohols having from 3 to 9
carbon atoms.
3. An ink-jet ink as in claim 2 wherein the aliphatic alcohol is
neopentyl alcohol.
4. An ink-jet ink as in claim 2 wherein the aliphatic alcohol is
3,5-dimethyl-1-hexyn-3-ol.
5. An ink-jet ink as in claim 1 wherein the organic solvent is
1,2-hexanediol.
6. An ink-jet ink as in claim 1 wherein the organic solvent is
present in an amount from about 8% to about 13% by weight.
7. An ink-jet ink as in claim 1 wherein at least one of each
component selected from the group consisting of buffers, biocides,
and metal chelators is present.
8. An ink-jet ink as in claim 1 having a pH ranging from 3 to about
9.
9. An inkjet ink as in claim 8 having a pH ranging from 6.5 to
about 8.
10. An ink-jet ink for ink-jet printing, comprising: from 0.1% to
5% by weight of at least one dye; from 8% to 20% by weight of an
organic solvent selected from the group consisting of
1,2-pentanediol, 1,2-hexanediol, and combinations thereof; from
0.1% to 5% by weight of an aliphatic alcohol or aliphatic alcohol
mixture; and from 0.1% to 1.5% by weight of at least one component
independently selected from the group consisting of buffers,
biocides, and metal chelators, with the proviso that no surfactant
is present in the ink-jet ink.
11. An ink-jet ink as in claim 10 wherein the aliphatic alcohol or
aliphatic alcohol mixture comprises alcohols having from 3 to 9
carbon atoms.
12. An ink-jet ink as in claim 11 wherein the aliphatic alcohol is
neopentyl alcohol.
13. An ink-jet ink as in claim 11 wherein the aliphatic alcohol is
3,5-dimethyl-1-hexyn-3-ol.
14. An ink-jet ink as in claim 10 wherein the organic solvent is
1,2-hexanediol.
15. An ink-jet ink as in claim 10 wherein the organic solvent is
present in an amount from about 8% to about 13% by weight.
16. An ink-jet ink as in claim 10 wherein at least one of each
component selected from the group consisting of buffers, biocides,
and metal chelators is present.
17. An ink-jet ink as in claim 10 having a pH ranging from 3 to
about 9.
18. An ink-jet ink as in claim 17 having a pH ranging from 6.5 to
about 8.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to ink-jet inks
having improved image quality and reliability.
BACKGROUND OF THE INVENTION
[0002] Thermal ink jet printers provide an effective means of
propelling ink jet inks onto various media including paper. These
printers can accomplish this by using resistive heater elements for
heating the ink to a boil, and propelling the ink through an
overlying orifice plate. Specifically, a typical ink-jet printhead
has an array of precisely formed nozzles located on a nozzle plate
and attached to an ink-jet printhead substrate. The substrate
incorporates an array of firing chambers that receive liquid ink
(colorants dissolved or dispersed in a solvent) through fluid
communication with one or more ink reservoirs. Each chamber has a
thin-film resistor located opposite the nozzle so ink can collect
between the firing resistor and the nozzle. Upon energizing a
particular resistor element, a droplet of ink is expelled through
the nozzle toward a print medium. Such printers, as typified by the
Hewlett-Packard DeskJet.TM. and DesignJet.TM. printers, are
desirable for use for several reasons. For example, thermal ink jet
printers have a relatively fast throughput while being relatively
inexpensive to run. Additionally, these printers are relatively
easy to use, and the ink is easily replaced.
[0003] There are several reasons that ink-jet printing has become a
popular way of recording images on various media surfaces,
particularly paper. Some of these reasons include low printer
noise, capability of high speed recording, and multi-color
recording. Additionally, these advantages can be obtained at a
relatively low price to consumers. However, though there has been
great improvement in ink-jet printing, accompanying this
improvement are increased demands by consumers in this area, e.g.,
higher speeds, higher resolution, full color image formation,
increased stability, new applications, etc. As new ink-jet inks are
developed, there are several traditional characteristics to
consider when evaluating the ink in conjunction with a printing
surface or substrate. Such characteristics include edge acuity and
optical density of the image on the surface, dry time of the ink on
the substrate, adhesion to the substrate, lack of deviation of ink
droplets, presence of all dots, resistance of the ink after drying
to water and other solvents, long-term storage stability, good dot
size and dot gain, color-to-color bleed alleviation, less chia,
acceptable coalescence, and long term reliability without corrosion
or nozzle clogging. Though the above list of characteristics
provides a worthy goal to achieve, there are difficulties
associated with satisfying all of the above characteristics. Often,
the inclusion of an ink component meant to satisfy one of the above
characteristics can prevent another characteristic from being met.
Thus, most commercial inks for use in ink-jet printers represent a
compromise in an attempt to achieve at least an adequate response
in meeting all of the above listed requirements.
[0004] Ink-jet ink compositions have tended to become more and more
complicated as demands for print quality have increased. In U.S.
Pat. No. 5,788,754, an ink-jet ink composition is described that
exhibits some desired properties of good ink-jet inks. For example,
when printed on gelatin-coated media, excellent color-to-color
bleed alleviation, good dot gain, good dot size, etc., are
observed. However, the formulation is somewhat complicated having a
large number of components. Thus, it is recognized that it would be
desirable to formulate ink-jet inks that provide some of the same
advantages of the inks of the prior art, while at the same time
providing ink-jet ink formulations that are simpler to manufacture
and less aggressive toward materials used in typical
printheads.
SUMMARY OF THE INVENTION
[0005] The present invention provides an ink-jet ink for ink-jet
printing, consisting of from 0.1% to 5% by weight of at least one
dye; from 8% to 20% by weight of an organic solvent selected from
the group consisting of 1,2-pentanediol, 1,2-hexanediol, and
combinations thereof; from 0.1% to 5% by weight of an aliphatic
alcohol or aliphatic alcohol mixture; from 0.1% to 1.5% by weight
of at least one component independently selected from the group
consisting of buffers, biocides, and metal chelators; and from
68.5% to 91.7% of water.
[0006] Alternatively, the present invention provides an ink-jet ink
for ink-jet printing, comprising from 0.1% to 5% by weight of at
least one dye; from 8% to 20% by weight of an organic solvent
selected from the group consisting of 1,2-pentanediol,
1,2-hexanediol, and combinations thereof; from 0.1% to 5% by weight
of an aliphatic alcohol or aliphatic alcohol mixture; and from 0.1%
to 1.5% by weight of at least one component independently selected
from the group consisting of buffers, biocides, and metal
chelators, with the proviso that no surfactant is present in the
ink-jet ink composition.
DETAILED DESCRIPTION OF THE INVENTION
[0007] For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to the
exemplary embodiments, and specific language will be used to
describe the same. It will nevertheless be understood that no
limitation of the scope of the invention is thereby intended. Any
alterations and further modifications of the inventive features
illustrated herein, and any additional applications of the
principles of the invention as illustrated herein, which would
occur to one skilled in the relevant art and having possession of
this disclosure, are to be considered within the scope of the
invention.
[0008] The singular forms "a," "an," and, "the" include plural
referents unless the context clearly dictates otherwise. Thus, for
example, reference to "a dye" includes reference to one or more of
such dyes.
[0009] As used herein, "effective amount" refers to the minimal
amount of a substance or agent, which is sufficient to achieve a
desired result. For example, an effective amount of an "ink
vehicle" is the minimum amount required in order to create an ink
composition, while maintaining properties necessary for effective
ink-jetting.
[0010] As used herein, "ink vehicle," refers to the composition in
which dyes are added to provide ink-jet ink compositions. Ink
vehicles are well known in the art, and a wide variety of ink
vehicles may be used with the systems, methods, and ink composition
of the present invention. However, with the present invention, the
ink-vehicle is defined by specific components in specific amounts,
and excludes common additives such as surfactants.
[0011] An "inkjet ink" or "ink composition" comprises an ink
vehicle, a dye, and water.
[0012] In one embodiment, the present invention provides an ink-jet
ink for ink-jet printing, consisting of from 0.1% to 5% by weight
of at least one dye; from 8% to 20% by weight of an organic solvent
selected from the group consisting of 1,2-pentanediol,
1,2-hexanediol, and combinations thereof; from 0.1% to 5% by weight
of an aliphatic alcohol or aliphatic alcohol mixture; from 0.1% to
1.5% by weight of at least one component independently selected
from the group consisting of buffers, biocides, and metal
chelators; and from 68.5% to 91.7% of water. In another embodiment,
the present invention provides an ink-jet ink for ink-jet printing,
comprising from 0.1% to 5% by weight of at least one dye; from 8%
to 20% by weight of an organic solvent selected from the group
consisting of 1,2-pentanediol, 1,2-hexanediol, and combinations
thereof; from 0.1% to 5% by weight of an aliphatic alcohol or
aliphatic alcohol mixture; and from 0.1% to 1.5% by weight of at
least one component independently selected from the group
consisting of buffers, biocides, and metal chelators, with the
proviso that no surfactant is present in the ink-jet ink
composition. Notably absent from these ink-jet ink compositions is
the presence of any traditional surface active agents such as
anionic or nonionic surfactants.
[0013] Turning to a discussion of each component of the ink-j et
ink compositions of the present invention, one component that must
be present is an aliphatic alcohol or aliphatic alcohol mixture.
Preferably, the aliphatic alcohol can comprise from 3 to 9 carbon
atoms. In particular, the use of neopenyl alcohol and/or
3,5-dimethyl-1-hexyn-3-ol are preferred. It has been recognized by
the inventors that, in accordance with the formulations of the
present invention, the addition of such alcohols can improve dot
gain, dot size, and ultimately, image quality.
[0014] With respect to the use of appropriate organic solvents of
the present invention, preferred organic solvents can be selected
from a group consisting of 1,2-hexanediol, 1,2-pentanediol, and
combinations thereof. Of these two organic solvents,
1,2-hexanediol, in most circumstances, is the most preferred
solvent for use. Though from 8% to 20% by weight circumscribes a
broad range that can be used, as a practical matter the organic
solvent is preferably present at from about 8% to about 13% by
weight. The concentration of the organic solvent within the ink-jet
ink composition is important as a goal of the present invention is
to provide ink-jet ink formulations having good dot size,
color-to-color bleed alleviation, improved coalescence, less chia
(solvent and dye migration at the beginning of a swath), and
improved print head materials compatibility.
[0015] Additional components must also be present in the ink-jet
ink formulations of the present invention. For example, the present
invention must have at least one component independently selected
from the group consisting of buffers, metal chelators, and
biocides. In one embodiment, one of each component is present.
[0016] Specifically, buffers can be used in the practice of the
present invention to modulate pH. These buffers can be
organic-based biological buffers or inorganic buffers. However, the
preferred buffers for use can be organic-based buffers. In the
ink-jet ink arts, a pH of around neutral is often desired for
certain applications. For example, a pH ranging from 3 to 9 can be
preferred. More specifically, in some embodiments, a pH from 6.5 to
8 can be desired. The buffers of the present invention can be used
to achieve such pH levels.
[0017] Examples of buffers that can be used include, but are not
limited to TRIZMA base, available from Aldrich Chemical,
4-morpholineethanesulfon- ic acid (MES), and
4-morpholinepropanesulfonic acid (MOPS). In one embodiment,
4-morpholinepropanesulfonic acid is a preferred buffer that can be
used.
[0018] The ink-jet inks of the present invention can comprise 0.1%
to about 1.5% by weight of a buffer. However, if other components
are present (chelator and/or biocide), then less than 1.5% will be
present. Thus, more preferably, the biocide will be present in the
ink-jet ink compositions at from 0.1% to about 0.5% by weight, with
a concentration from about 0.1% to about 0.3% being even more
preferred.
[0019] Turning to the metal chelator component, such metal
chelators that are capable of binding transition metal cations can
be present. A classic metal chelator known in the chemical arts is
ethylenediaminetetraacetic acid (EDTA), which can be added to the
ink-jet inks of the present invention. Other metal chelators can
also be added such as diethylenetriaminepentaacetic acid (DTPA),
trans-1,2-diaminocyclohexanete- traacetic acid (CDTA),
(ethylenedioxy) diethylenedinitrilotetraacetic acid (EGTA), or
other chelators that can bind transition metal cations.
Ethylenediaminetetraacetic acid (EDTA) and
diethylenetriaminepentaacetic acid (DTPA) are more preferred metal
chelators that can be used. Particularly, the use of
ethylenediaminetetraacetic acid (EDTA) in its disodium salt form
can be employed in the practice of the invention with good
results.
[0020] If a metal chelator is used, then from 0.1% about 1.5% by
weight can be present in the formulation. However, if other
components are present (buffer and/or biocide), then less than 1.5%
will be present. Thus, more preferably, the metal chelator will be
present in the ink-jet ink compositions at from 0.1% to about 0.5%
by weight, with a concentration from about 0.1% to about 0.3% being
even more preferred.
[0021] Any of the biocides commonly used in ink-jet inks can also
be used in the formulations of the present invention, provided the
biocide does not substantially adversely affect the properties that
are being sought with the present invention, e.g., good dot size,
color-to-color bleed alleviation, improved coalescence, less chia,
and improved print head materials compatibility. Examples of
biocides that can be used include, but are not limited to, NUOSEPT
95, available from Huls America; PROXEL GXL, available from Zeneca;
and glutaraldehyde, available from Union Carbide Company under the
trade designation UCARCIDE 250. The use of PROXEL GXL is
preferred.
[0022] The inks of the present invention can comprise from 0.1% to
1.5% by weight of a biocide. However, if other components are
present (buffer and/or metal chelator), then less than 1.5% will be
present. Thus, more preferably, the biocide will be present in the
ink-jet ink compositions at from 0.1% to about 0.5% by weight, with
a concentration from about 0.1% to about 0.3% being even more
preferred.
[0023] Turning now to the colorants that can be used with the
ink-jet ink compositions of the present invention, any dye can be
used that provides a desired color to the ink-jet ink, while not
substantially diminishing the properties that are desired to be
achieved with the present invention. Thus, the solubility of the
dye in the ink vehicle and the intensity of the color should be
considered when selecting an appropriate dye. In the context of the
present invention, the dye should be present in the inkjet ink
formulation at from about 0.1% to 5% by weight. The dyes can be
colored or black dyes, depending on the application or desired use.
Examples of dyes that can be used include, but are not limited to,
Direct Blue 199 (available form Zeneca Colors as Projet Cyan
Special), Direct Red 9, Direct Red 227, Magenta 377 (available from
Ilford AG, Rue de l'Industrie, CH-1700 Fribourg, Switzerland), Acid
Yellow 23, Direct Yellow 86, Yellow 104 (Ilford AG), Direct Yellow
4 (BASF), Yellow PJY H-3RNA (Zeneca Colors), Direct Yellow 50
(Zenceca Colors), Pacified Reactive Black 31, and other similar
dyes. The most preferred dyes for use include, Direct Blue 199,
Magenta 377, Ilford Yellow 104, and Pacified Reactive Black 31.
Thus, one of each color, i.e., cyan, magenta, and yellow, and black
ink-jet inks can be formulated for use.
EXAMPLES
[0024] The following examples illustrate the preferred embodiments
of the invention that are presently best known. However, other
embodiments can be practiced that are also within the scope of the
present invention.
Example 1
[0025] A cyan inkjet ink was prepared according to the following
formulation (each by weight):
1 1.50% Direct Blue 199 0.10% ethylenediaminetetraacetic acid
(EDTA) (metal chelator) 0.15% 4-morpholinepropanesulfonic acid
(MOPS) (buffer) 0.20% PROXEL GXL (biocide) 9.25% 1,2-hexanediol
0.50% neopentyl alcohol balance water
Example 2
[0026] A cyan ink-jet ink was prepared according to the following
formulation (each by weight):
2 1.50% Direct Blue 199 0.10% ethylenediaminetetraacetic acid
(EDTA) (metal chelator) 0.15% 4-morpholinepropanesulfonic acid
(MOPS) (buffer) 0.20% PROXEL GXL (biocide) 11.25% 1,2-hexanediol
0.50% neopentyl alcohol balance water
[0027] Example 3
[0028] A cyan ink-jet ink was prepared according to the following
formulation (each by weight):
3 1.50% Direct Blue 199 0.10% ethylenediaminetetraacetic acid
(EDTA) (metal chelator) 0.15% 4-morpholinepropanesulfonic acid
(MOPS) (buffer) 0.20% PROXEL GXL (biocide) 9.25% 1,2-hexanediol
1.50% 3,5-dimethyl-1-hexyn-3-ol 0.50% neopentyl alcohol balance
water
Example 4
[0029] A black ink-jet ink was prepared according to the following
formulation (each by weight):
4 1.48% Pacified Reactive Black 31 0.10% ethylenediaminetetraacetic
acid (EDTA) (metal chelator) 0.15% 4-morpholinepropanesulfonic acid
(MOPS) (buffer) 0.20% Proxel GXL (biocide) 9.25% 1,2-hexanediol
0.50% neopentyl alcohol balance water
Example 5
[0030] A yellow ink-jet ink was prepared according to the following
formulation (each by weight):
5 3.00% Yellow 104 0.10% ethylenediaminetetraacetic acid (EDTA)
(metal chelator) 0.15% 4-morpholinepropanesulfonic acid (MOPS)
(buffer) 0.20% PROXEL GXL (biocide) 9.25% 1,2-hexanediol 0.50%
neopentyl alcohol balance water
Example 6
[0031] A magenta ink-jet ink was prepared according to the
following formulation (each by weight):
6 2.35% Magenta 377 0.10% ethylenediaminetetraacetic acid (EDTA)
(metal chelator) 0.15% 4-morpholinepropanesulfonic acid (MOPS)
(buffer) 0.20% PROXEL GXL (biocide) 9.25% 1,2-hexanediol 0.50%
neopentyl alcohol balance water
Example 7
Evaluation of Print Quality (Dot Size)
[0032] To evaluate dot size, dots were placed on a gelatin coated
ink-jet media (H-P Photosmart Glossy, C5982A) by ejecting single
dots from an ink-jet photo printer. Generally speaking, a dot size
from about 80 to 110 microns can be desired when using this
printer/media combination at 1200 dpi. Smaller dot sizes tend to
lead to images having inferior quality due to either or both
insufficient covering of the pixels and lack of hiding power for
the printing defects, e.g., misfiring of nozzles. Conversely,
larger dot sizes tend to exhibit blurry and ill-defined images.
Specifically, dot size was evaluated visually under the microscope.
The following table illustrates the dot size in microns for each
ink-jet ink prepared in Examples 1-6.
7 TABLE 1 INK-JET INK DOT SIZE (.mu.m) Example 1 110 Example 2 94
Example 3 102 Example 4 109 Example 5 111 Example 6 108
[0033] Table 1 above shows that by utilizing the formulations of
Examples 1-6, acceptable dot size compared to an optimal dot size
can be achieved.
[0034] While the invention has been described with reference to
certain preferred embodiments, those skilled in the art will
appreciate that various modifications, changes, omissions, and
substitutions can be made without departing from the spirit of the
invention. It is intended, therefore, that the invention be limited
only by the scope of the following claims.
* * * * *