| 摘要 |
PURPOSE:To deal with a change in the quantity of light from a light source for exposing by detecting the light transmittance of an original together with the quantity of light from the light source for exposing and controlling or correcting a conveyance speed. CONSTITUTION:A detection circuit 40 for insertion of an original including a detector 20 outputs a detection signal to a detection circuit 42 (an optical fiber 14 and a photosensor 16) for quantity of light. The circuit 42 detects the quantity of light from a light source 10 and outputs the same to the 1st signal holding circuit 46. When the original is conveyed to the position between an optical fiber 14 and a photosensor 16, the signal corresponding to the light transmitting the original is outputted to a peak value detector 48. An arithmetic circuit 50 compensates the light transmittance of the original and feeds the corrected signal, via an AD converter 52, to the 2nd signal holding circuit 54. When the forward ends of the original and photosensitive paper are conveyed just before a conveyance roll 26 in a printing section, the circuit 54 impresses the peak value signal held therein, via a DA converter 56, to a motor speed control circuit 60, thereby controlling the rotating speed of a motor 28. |
