Bleed alleviation in ink-jet inks using organic acids
US5785743A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 6, 1995 |
| Grant date | Jul 28, 1998 |
| Priority date | — |
| Expiry date | Dec 6, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09D11/40
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
An organic acid component is employed in a first ink-jet ink composition to reduce the pH differential required to render insoluble the pH-sensitive colorant of a second encroaching ink-jet ink composition. By inducing the precipitation of the pH-sensitive colorant, migration of the colorant is inhibited, thereby substantially reducing bleed between the pH-sensitive ink and the ink containing the organic acid (the "target" ink). The organic acid component is employed at a concentration ranging from about 0.25 to 20 wt % and may be represented by such as acids as polyacrylic, acetic, glycolic, malonic, malic, maleic, ascorbic, succinic, glutaric, fumaric, citric, tartaric, lactic, sulfonic, ortho-phosphoric acid, derivatives thereof. Without the organic acid component, a pH differential on the order of at least 4 and more likely 5 units must exist between the pH-sensitive ink and the target ink to substantially eliminate bleed. By employing an organic acid in the practice of the invention, a pH differential on the order of only 1 to 3 units may be required. Therefore, assuming the pH-sensitive ink has a pH of about 8, the pH of the target ink could be as high as 7 in the practice of…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.