Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2001-02-26
2003-06-24
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031470, C106S031490, C106S031760, C106S031770, C106S031780, C106S031570, C106S031860
Reexamination Certificate
active
06582501
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for INK COMPOSITION FOR INK-JET PRINTERS earlier filed in the Korean Industrial Property Office on the of Sep. 22, 2000 and there duly assigned Ser. No. 00-55198.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink composition for ink-jet printers which can be effectively used with dyes or pigments and which is easy to fix and has excellent waterfastness (water resistance) and smearfastness (smear resistance) after printing, and has good storage stability and excellent wetness at nozzles (anti-clogging of nozzles).
2. Description of the Related Art
Ink-jet printing, a type of non-impact printing, produces less noise than that produced by impact printing, and it is easier to implement color printing by the ink-jet printing technique than by a laser beam printing technique. The major types of non-impact printing processes include a continuous inkjet process and a drop-on-demand (DOD) process. In continuous inkjet processes, the direction of jetting is adjusted by changing the electric field during continuous jetting of ink. DOD processes, which expel droplets of ink for printing, include thermal-bubble ink jet processes and piezoelectric ink jet processes. As for thermal-bubble ink jet processes, a bubble of ink vapor is created by heating and is substantially expelled due to the resultant increase in pressure. In contrast, piezoelectric ink jet processes adopt a piezoelectric oscillator to generate pressure required to expel the ink. The piezoelectric oscillator deforms by the application of electricity, thereby producing pressure to discharge the ink.
On the other hand, ink-jet ink compositions basically include a chromophore as a colorant, and a vehicle. Ink-jet ink compositions for color printing should have physical properties suitable for a printing device and should be easily fixed or absorbed onto a target recording medium, so as to produce a desired print. In particular, the following conditions are generally required for ink-jet ink compositions, and the compositions include a variety of components:
(1) the ink composition should have a proper viscosity and surface tension, so as to produce a high optical density, a high dot uniformity and a high jetting stability.
(2) the ink composition should dry rapidly with minimal color-to-color bleed
(3) the ink composition should have good storage stability.
(4) the ink composition should have good color characteristics for properties such as hue, lightness and saturation.
(5) the ink composition should be attractive to a printer head or a recording medium such as paper or overhead projector film. That is, it should have the properties of smearfastness and waterfastness.
Many approaches have been taken to develop an ink composition with improved performance, as may be seen in U.S. Pat. Nos. 5,108,503, 5,858,075, 5,980,622, 5,990,202, 6,057,384, 5,641,346, 5,679,724, 5,936,008, 5,969,033, 6,025,412, 5,324,349, 5,421,871, 5,690,723, 5,704,969, 5,972,086, 6,039,796, and 6,095,645. A method of improving the storage stability and wetness at nozzles of the ink composition and the drying time after discharging of the ink has been disclosed using a variety of nitrogen-containing heterocyclic compounds, such as 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone. The above-listed disclosures, which utilize nitrogen-containing heterocyclic compounds, such as 2-pyrrolidone, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone, explain the reasons for the improvements in storage stability, wetness at nozzles and drying time as follows.
Nitrogen-containing heterocyclic compounds have a stronger dipole moment than water. Thus, such compounds are miscible with water at the molecular level through dipole—dipole interaction with water. However, the nitrogen-contained heterocyclic compounds have a stronger affinity than water for the functional groups of a chromophore, or coloring agent, contained in ink compositions, which enables the chromophore to dissolve in the composition, so that the chromophore can remain dispersed without aggregation and precipitation of the chromophore when the ink composition is preserved in a cartridge.
On the other hand, when the nozzle of an ink jet printer is exposed to the air, the nozzle can be clogged due to evaporation of volatile components from the ink composition, which causes clogging and thus a problem in discharging ink through the nozzle occurs. To avoid the problem of clogging, some degree of wetness is required for the ink composition. At the same time, the ink composition should dry rapidly, such that less color-to-color bleeding and smearing occur after jetting. Consistent with these requirements, the nitrogen-contained heterocyclic compound is hydrophilic and has a low vapor pressure, which prevents the evaporation of water. As a result, the nozzle can be kept wet even when the nozzle is exposed to the air for a longer period of time, thereby preventing clogging of the nozzle. In addition, a low surface tension of the nitrogen-contained heterocyclic compound allows easy penetration of droplets of ink into porous paper, thereby facilitating drying of the ink on paper.
However, the disclosed ink compositions provide an improved storage stability, wetness at nozzles, and fast-drying property only when a dye is added as a chromophore. Here, “dye” refers to a water-soluble chromophore, and “pigment” to a water-insoluble chromophore. As for pigment-based ink compositions, the storage stability is less improved. This is because the pigment contains a small number of hydrophilic functional groups, compared with the dye, thus hindering a stable reaction with the existing nitrogen-contained heterocyclic compound. As for dye-based ink compositions, waterfastness and smearfastness after printing are still unsatisfactory, thereby degrading the quality of print.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved ink composition for ink-jet printers.
It is another object of the invention to provide an ink having improved storage stability.
It is a further object of the invention to provide an ink having wetness at nozzles.
It is a yet further object of the invention to provide an ink having excellent waterfastness (water resistance) and smearfastness (smear resistance) after jetting, either when a dye or a pigment is used as a chromophore.
To achieve the objective of the present invention, there is provided an ink composition for ink-jet printers, comprising a chromophore, a solvent, a co-solvent, a humectant, a surfactant, a viscosity adjuster, and an additive, wherein the additive is a nitrogen-containing heterocyclic in compound having formula:
where each of R
1
and R
2
is independently selected from —CH
2
OH, —CH
2
CH
2
OH, —CH
2
CH(OH)(CH
2
)
n1
CH
3
(n1 is an integer from 1 to 5), —CH
2
CH(OH)(CH
2
)
n2
OH (n2 is an integer from 1 to 6), —CH
2
CH(OH)(CH
2
)
n3
NH
2
(n3 is an integer from 1 to 6), —CH
2
CH
2
O(CH
2
CH
2
O)
n4
CH
2
CH
2
OH (n4 is an integer from 1 to 10), —CH
2
CH(OH)(CH
2
CH
2
O)
n5
CH
2
CH
2
OH (n5 is an integer from 1 to 10), —CH
2
CH(OH)(CH
2
CH
2
NH)
n6
CH
2
CH
2
OH (n6 is an integer from 1 to 9), —CH
2
CH(OH)(CH
2
CH(OH))
n7
CH
2
CH
2
OH (n7 is an integer from 1 to 10), —CH
2
CH(OH)(CH
2
CH(CN))
n8
CH
2
CH
2
OH (n8 is an integer from 1 to 10), —CH
2
CH(OH)(CH
2
CH(COONH
2
))
n9
CH
2
CH
2
OH (n9 is an integer from 1 to 10) or —CH
2
CH(OH)(CH
2
CH(COO(CH
2
)
m
NH
2
))
n10
CH
2
CH
2
OH (n10 is an integer from 1 to 10, and m is an integer from 1 to 5);
where x and y are integers and (0≦x+y≦8); and
where each of R
3
and R
4
is independently selected from —H, —CH
3
, —CH
2
OH, —CH
2
CH
2
OH, —CH
2
CH(OH)(CH
2
)
n1
CH
3
(n1 is an integer from 1 to 5), —CH
2
CH(OH)(CH
2
)
n2
OH (n2 is an integer is from 1 to 6), —CH
2
CH(OH)(CH
2
)
n3
NH
2
(n3 is an integer from 1 to 6), —CH
2
CH
2
O(CH
2
CH
2
O)
n4
CH
2
CH
Cha Jun-hoe
Jang Seung-soon
Ryu Seung-min
Bushnell , Esq. Robert E.
Klemanski Helene
Samsung Electronics Co,. Ltd.
LandOfFree
Ink composition for ink-jet printers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink composition for ink-jet printers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink composition for ink-jet printers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3092124