| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that adjusting a quantity of laser light at a real time in a sampling period to a target quantity of light requires a high speed digital data process and a high speed D/A converter, which involves a cost increase compared to the case where a conventional analog circuit is used. SOLUTION: The image forming apparatus includes: a PD 501 for detecting a quantity of laser light emitted from a laser 502; a comparator 515 for comparing a digital value corresponding to the quantity of laser light detected by the PD 501, with a digital value corresponding to the target quantity of laser light; a computing section 508 for calculating a control value that determines a driving current for driving the laser according to the comparison result; and a switching constant current section 503 for driving the laser with the driving current according to the control value obtained by the computing section 508. The driving current for the laser in the exposure scanning of a present scanning line is determined by a control value obtained based on a quantity of laser light used for scanning lines before the present one. COPYRIGHT: (C)2009,JPO&INPIT
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