| 摘要 |
PURPOSE:To obtain high-quality images, by storing image information corresponding to at least three light beam lines in an auxiliary scanning direction, detecting the image information in the surrounding of a spot position of a light beam for irradiation on the basis of the stored information, and switching spot diameter in at least three steps under control. CONSTITUTION:A light quantity-detecting logical circuit 11 has three shift registers 20-22, each of which corresponds to one scanning, as storage means for scanning signals. When all of signals P2, P3 for spot positions adjacent to each other in a main scanning direction and signals P4, P5 for spot positions adjacent to each other in the auxiliary scanning direction are in a laser-ON state whereas at least one of signals P6-P9 for other adjacent spot positions is in a laser-OFF state, a light quantity-judging part 23 outputs a signal 14 for reducing the quantity of laser light to a laser driver. When at least one of the signals P2-P5 for the spot positions adjacent to each other in the main or auxiliary scanning direction is in the laser-OFF state, a signal 13 for a normal quantity of laser light is outputted, whereas when all of the signals P2-P9 for the adjacent spot positions in the laser-ON state, a signal 16 for increasing the laser light quantity is outputted. |
