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:
Jul. 04, 1989
Filed:
May. 23, 1988
Kenichirou Asada, Tokyo, JP;
Ricoh Co., Ltd., Tokyo, JP;
Abstract
A synchronizing device is used in a laser printer which comprises a polygonal mirror for periodically deflecting a laser beam which scans a scanning plane and a photodetector provided on the scanning plane outside a region in which a printing is made by the laser beam for outputting an output signal when the laser beam is detected. The output signal of the photodetector is used for producing an image scan clock signal which synchronizes each scan of the laser beam. The synchronizing device comprises a pulse generating circuit for generating a plurality of pulse signals having a frequency identical to that of the image scan clock signal and having phases which are successively shifted by a constant phase with respect to each other, a clock selecting circuit for selectively outputting one of the plurality of pulse signals generated by the pulse generating circuit as the image scan clock signal, and a setting circuit for arbitrarily setting the pulse signal to be selectively outputted from the clock selecting circuit responsive to the output signal of the photodetector.