| 摘要 |
PURPOSE: To prevent deterioration of resolution or the like and to detect a replacement period of an exposure lamp by revising an amplification factor in response to a signal obtained by A/D-converting a reflected light when a light emission position of a read object is opposite to a reference board. CONSTITUTION: At application of power, a control section 101 drives a mechanism control section 105 and when a carriage provided with a reflector reflecting a light from an exposure lamp 25 is moved to a position opposite to a center of a white reference board, the exposure lamp 25 is lighted. After lighting for a prescribed time, the white reference board is read by one line in the main scanning direction and a peak of the line is detected, and when the peak level is smaller than the setting level, an amplification factor of an amplifier of an image processing unit 106 is increased by one step. Then the comparison between the peak level and the setting value is repeated to set a gain of the amplifier suitable for a reference signal of an A/D converter. Then the relation between the reference signal of the A/D converter and the gain of the amplifier is made proper to prevent deterioration in the resolution or loss of high density. |
