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:
May. 12, 1998
Filed:
Nov. 14, 1995
Robert H Melino, Webster, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
The present invention discloses a dynamic control of a drive circuit to a diode laser used in a raster output scanning system. In the prior art, the binary serial stream input to a diode laser operates on the laser to pulse the laser on when a 'one' input is applied, the laser staying on when the first one input is immediately followed by successive one inputs. The first on pixel creates an exposure at an image plane which is less than uniform due to the characteristics of the drive circuit due to the overshoot or undershoot characteristics of the drive circuit. The second and succeeding pixels following the first pixel turned on will be at a maximum exposure value and hence will have an undesirable exposure contrast with the first pixel. The present invention adds delay circuitry to the drive circuits of the diode laser to introduce a gating signal which delays the application of the pixel stream to the laser diode in such a way that each successive on pulse is cycled on and off therefore each exposure value of each on pixel is exactly the same. Additional circuitry is included to compensate for the loss of exposure by increasing the laser diode output.