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:
Nov. 23, 1993
Filed:
Jan. 23, 1992
Mary A Hadley, Rochester, NY (US);
Jeffrey A Small, Rochester, NY (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
In a non-impact printer apparatus such as an LED printhead a current mirror driver is used to control current to the recording elements, e.g., LED's. The current mirror driver is incorporated in an integrated circuit driver chip and a plurality of these chips are provided on the printhead. Each chip includes two sets of digitally addressable transistors. This allows for individual chip control of current to the respective LED's to correct for nonuniformity of light output from chip to chip due to temperature gradients as well as controlling for light output due to aging of the printhead. A continuously conducting transistor is associated with each set of addressable transistors to provide a minimum offset bias current level and selective activation of the addressable transistors provides for selective increase of a bias current over the minimum level. The bias current is mirrored in those LED's selected for activation.