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:
Dec. 12, 2000
Filed:
Jul. 30, 1999
Takami Maeda, Fukuoka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A phase-difference-measuring-circuit counts time-lags of beam-detect-signals with regard to a reference beam-detect-signal based on a reference clock. The counted values are stored in respective registers. When register-load-signals are set to 'active', the stored values are loaded to pulse-generating-circuits, and counters in the pulse-generating-circuits count down the stored values based on the reference clock. During this count down operation, pulse-generating-circuits output one-shot-pulse-signals. When the on-shot-pulse-signals stays active, frequency dividers are set to 'disable' and stop their operations. Duties of motor clocks driving rotary polygons in laser-beam-scanning-units are temporarily varied during this period, and the motor clocks are outputted with phase delay corresponding to this period, thereby correcting phase deviation in the main scan direction of the polygons.