| 摘要 |
PROBLEM TO BE SOLVED: To stably make a quantity of light constant regardless of variation of a power supply voltage, to enable a level of a reference signal of an automatic power control (APC) to be adjusted or set in a relatively wide range, to reduce effects of noise of the APC, and moreover to attain improvement of an image quality by solving generation of image density irregularities caused by quantity of light variation. SOLUTION: The light emitting driving device is equipped with a quantity of light reference signal generating means 70 which generates a quantity of light reference signal, and a driving means 80 which drives a light emitting element LD to emit light by a quantity of light corresponding to the quantity of light reference signal. The quantity of light reference signal generating means 70 includes a reference voltage generating means (71) which outputs a constant voltage signal regardless of the variation of the power supply voltage, and constant voltage output means 72, 73 and 74 which output to the driving means 80 a constant level signal that has a level ratio of the signal generated to the constant voltage signal made constant regardless of the variation of the power supply voltage by generating the signal corresponding to the constant voltage signal, feeding back the signal and comparing with the constant voltage signal. COPYRIGHT: (C)2007,JPO&INPIT
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