| 摘要 |
PURPOSE:To eliminate the need for an output compensate circuit when an AC power source is used for a light source and to correct the quantity of light appropriately all the time by using a DC power source for the light source for a scan on an original and controlling its applied voltage independently according to a filter in use. CONSTITUTION:An original is image-formed on a CCD through respective filters R, G, and B and a photoreceptor is exposed to a beam according to the signal of the CCD to form an electrostatic latent image. When a scan start instruction for the original is inputted to a CPU 35, a soft starting circuit 39 is activated to turn on a lamp 9. At the same time, transistors (TRs) Q3-Q5 are selected by a signal corresponding to the color of the filter to correct the quantity of light. The power source for the light source is changed from AC to DC by a rectifying circuit, the secondary voltage of a transformer T1 is connected to comparators 44A and 44B, and oscillations of the TRs Q1 and Q2 are controlled according to their outputs to control the quantity of light. |
