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:
Apr. 28, 1998
Filed:
Jan. 16, 1996
Katsuhiko Nishizawa, Kanagawa, JP;
Fuji Xerox Co., Ltd., Tokyo, JP;
Abstract
A digital image forming apparatus is constructed to accurately detect period abnormality of a horizontal sync signal. In the apparatus, a sync signal generation portion outputs the horizontal sync signal by a received light signal from a light position detector. A sync signal abnormality monitor monitors whether a detected period of the sync signal is longer than a reference period, or it is normal. When the output signal of the sync signal is judged to be longer than the reference period, an abnormality detecting signal is supplied to a continuous turning-on portion. When the continuous turning-on portion receives the abnormality detecting signal, it issues an instruction to a synchronizing turning-on portion so that video data continues to be turned on, that is, turning-on signal is continuously outputted. Since a laser beam is continuously turned on by this instruction, the light position detector can certainly receive the laser beam. Accordingly, the period of the sync signal can be accurately detected and the cause of period abnormality can be specified.