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. 24, 2001
Filed:
Jun. 02, 1999
Kazuro Yamada, Shizuoka-ken, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In an electrophotographic image formation, a driving current for laser emission is pulse-width-modulated in correspondence with externally input image data. The pulse width modulation of the driving current is started after a predetermined time period has passed from a time point of beam detection by a light detector located at a position leading a photosensitive drum in a main scanning direction. The driving current is adjusted in correspondence with the light amount detected. Current adjustment data is supplied to a current modulation circuit in the same manner as image data. Detection is made of the laser beam, which is pulse-width-modulated by the current modulation circuit on the basis of the supplied adjustment data, and is emitted from the laser light source, by a laser monitor device under control of a monitor controller. Data supply and detection control by the monitor controller are started after a predetermined time period has passed from a time point of beam detection by the detector, when a pulse width of the current modulation circuit is adjusted in correspondence with the detected light amount.