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. 24, 1992
Filed:
Nov. 04, 1991
Michael W Mattern, Hamlin, NY (US);
Jeremy K Chung, Greece, NY (US);
Kenneth D Kieffer, Rochester, NY (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
A non-impact printhead for use in recording on a recording medium includes a plurality of energizable recording elements such as LED's. Integrated circuit driver chips are provided that include a current mirror having a master circuit for generating a reference current and a plurality of slave circuits for providing respective driver currents to the recording elements selected for energization. A transistor switch is in series with a respective recording element and switchable from one state to another in response to a signal at its control electrode. An enabling circuit operating upon the control electrode switches the transistor switch to allow current to be selectively provided to the recording element for a predetermined period of time. Each of the slave circuits include an additional slave circuit which provides a current path for facilitating changing of the signal at the control electrode from on voltage level to another such as by allowing a capacitive charge at the control electrode to dissipate. A reference voltage is generated for driving the recording elements. A second transistor in series with the transistor switch establishes a first voltage signal that is input to one electrode of the transistor switch. The first voltage signal varies with variations in the reference voltage. The additional slave circuit generates a voltage signal at the control electrode of the transistor switch means that varies with the reference voltage. Thus, variations in the reference voltage will not substantially affect the level of current driven to the LED's during recording of a pixel.