The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 28, 1998
Filed:
Dec. 06, 1995
Raymond J Adamic, Corvallis, OR (US);
James P Shields, Philomath, OR (US);
Mark H Kowalski, Corvallis, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
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 the invention as opposed to a pH of about 3 in the absence of an organic acid component.