| 摘要 |
PURPOSE:To increase a copying speed and to prevent an abnormal rise in temperature from occurring when small originals are copied continuously by deciding whether an exposure range determined by the size of copying paper and copying magnification is larger than a set value or not an controlling the exposure range. CONSTITUTION:The timing of the head of copying paper which abuts on a register roller 42 is detected by a detection switch 46 and the discharging of the copying paper is confirmed by a detection switch 47. Signals of the switches 46 and 47 are inputted to an exposure range control part to control and optical part movement control part and a light source turning-on control part. Exposure is carried out within ranges L1 and L2 corresponding to the size for originals D in sections X and Y of copying paper size and copying magnification and a light source is moved by a specific range L3 for an original of size Z, but turned on corresponding to only the original size. Thus, exposure corresponding to the original size is carried out for the original larger than a specific range to speed up copying operation and the exposure is limited when the original is smaller than the specific range to prevent an original platen 11 from rising in temperature locally and abnormally. |
