Ink jet ink

Details Ink jet ink Ink jet ink

1999-12-20

2001-07-10

KLemanski, Helene (Department: 1755)

Compositions: coating or plastic

Coating or plastic compositions

Marking

C106S031860, C523S160000, C523S161000

Reexamination Certificate

active

06258155

ABSTRACT:

FIELD OF THE INVENTION
This application relates to an ink jet ink using an alcohol carrier and a particular dispersant.
BACKGROUND OF THE INVENTION
Ink jet printing is a non-impact method for producing images by the deposition of ink droplets on a substrate (paper, transparent film, fabric, etc.) in response to digital signals. Ink jet printers have found broad applications across markets ranging from industrial labeling to short run printing to desktop document and pictorial imaging. The inks used in ink jet printers are generally classified as either dye-based or pigment-based.
In pigment-based inks, the colorant exists as discrete particles. These pigment particles are usually treated with addenda known as dispersants or stabilizers which serve to keep the pigment particles from agglomerating and settling out of the carrier. Such a dispersant is necessary to produce a colloidally stable mixture and an ink that can be “jetted” reliably without clogging the print head nozzles.
Dispersing agents in an ink jet ink have the dual function of helping to break down pigments to sub-micron size during the milling process and of keeping the colloidal dispersion stable and free from flocculation for a long period of time. In general, dispersions suffer from poor colloidal stability due to particle agglomeration and/or sedimentation, thus limiting the usefulness of the dispersions in inks.
Although a wide variety of dispersing agents are known for pigmented ink jet inks, they are not without certain problems. For example, many dispersing agents are very selective as far as being able to disperse pigments to sub-micron size. In many instances, each class of pigments may require a specific dispersing agent. Another problem encountered with some polymeric dispersing agents is that they tend to impart an undesirably high viscosity to the resulting inks. Thus, there is a continuing need for improved dispersing agents for pigmented inks, especially for non-aqueous inks.
Dispersing agents for non-aqueous ink jet inks previously used include metal salts of styrene-acrylic copolymers, metal salts of sulfonated styrene-acrylic copolymers, phosphonium salts or quaternary ammonium salts of styrene-acrylic copolymers.
U.S. Pat. Nos. 5,837,046; 5,739,833 and 5,538,548 relate to ink jet inks containing various Disperbyk® dispersants used in a variety of carriers such as aliphatic hydrocarbons and dibasic esters. However, there is a problem with these dispersants in that they do not provide very low particle size dispersions when used with alcohol carriers.
It is an object of this invention to provide an ink jet ink having a low particle size in order to obtain better covering power and which would have less tendency to clog the ink jet nozzles. It is another object of this invention to provide a non-aqueous, pigment dispersion for an ink jet ink which employs a dispersant which enables the production of nanometer-size pigment particles.
SUMMARY OF THE INVENTION
These and other objects are achieved in accordance with this invention which relates to a ink jet ink composition comprising from about 30 to about 90% by weight of an alcohol carrier, from about 0.5 to about 30% by weight of a pigment, from about 0.125 to about 7.5% by weight of an amine-terminated polyether dispersant, and from about 10 to about 50% by weight of a humectant.
The dispersant used in the ink jet ink of the invention is highly effective in reducing pigment particles to a size of less than about 100 nm when milled in the presence of very fine milling media. The resulting dispersion is characterized by nanometer-size pigment particles. The dispersing agents employed are useful with a wide variety of pigments.


REFERENCES:
patent: 4877451 (1989-10-01), Winnick et al.
patent: 5129948 (1992-07-01), Breton et al.
patent: 5538548 (1996-07-01), Yamazaki
patent: 5538549 (1996-07-01), Kato et al.
patent: 5679138 (1997-10-01), Bishop et al.
patent: 5739833 (1998-04-01), Yamazaki et al.
patent: 5788759 (1998-08-01), Takao et al.
patent: 5837046 (1998-11-01), Schofield et al.
patent: 5888287 (1999-03-01), Brown et al.
patent: 5951749 (1999-09-01), Krepski et al.

Affiliated with

Also associated with

Rating

Ink jet ink 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 jet ink, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet ink will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2510178