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. 30, 1989
Filed:
Nov. 30, 1987
Donald V Mager, St. Paul, MN (US);
James A Howe, Burnsville, MN (US);
Printware, Inc., Mendota Heights, MN (US);
Abstract
A photosensitive, photoconductive media moving in a first direction relative to a laser light beam scanning in a second direction, transverse to the first direction, incurs velocity variations. These velocity variations result in variations in the absolute and relative heights of white and black image features. This printed image nonuniformity is especially visually detectable for closely spaced parallel lines in the second direction, and/or gray scale. An optical velocity sensor senses instantaneous media velocity. An analog or digital velocity error processor maintains a running average velocity and determines, by subtraction, an instantaneous velocity error as the difference between currently sensed and running average velocities. The instantaneous velocity error so determined is used to adjust the intensity of the laser light beam to be proportionally brighter (dimmer), exposing a wider (narrower) scan line, on a faster-moving (slower-moving) media region. By this compensating, the ratio of white and black image features is maintained constant during media velocity variations.