Fitzpatrick, Cella, Harper & Scinto
Image recording apparatus using optical beam
 In a laser beam printer, automatic optical quantity (APC) control is performed based on an optical quantity detection output to generate a laser beam having a predetermined quantity of light. In each scanning cycle, APC is effected by utilizing a period (unblanking period) in which the laser device is forcibly actuated to generate a horizontal synchronization signal. The unblanking period may be changed according to the print paper size or image formation/non-image-formation periods. Also, light quantity control may be effected through a plurality of scanning cycles before image formation and may be effected by utilizing the unblanking period during the period corresponding to the intervals of print sheets. Techniques also provided to prevent a transfer unit from being contaminated by toner images formed as a byproduct of APC. 
Canon Kabushiki Kaisha
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G03G G03G G03G B41J G03G
additional additional inventional inventional inventional
Makoto Seiji Akio Yukihide Youji Kazurou Shinpei Junichi
Takeuchi Uchiyama Noguchi Ushio Serizawa Yamada Matsuo Kato