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:
Jun. 20, 2000
Filed:
Nov. 10, 1997
Makoto Nukui, Tokyo, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
In a laser scan based recording apparatus, laser light from a measuring laser diode is directed to one reflecting surface of a polygonal mirror. The reflected light is detected with a measuring photodiode. The reflectance of laser light is calculated from the detection output of the measuring photodiode and a reference voltage is generated. When the reflecting surface has rotated to the position where the laser light from laser light source scans a photoreceptor drum, the emission output of the laser light source is controlled by a laser output control circuit on the basis of the generated reference voltage. Despite variation in reflectance among the multiple reflecting surfaces of the polygonal mirror, the photoreceptor is scanned with a constant optical intensity of laser light. Since automatic power control is performed at all times, overdriving of the laser diode is effectively prevented to protect it against breakdown, producing consistent and highly reliable laser power control.