| 摘要 |
PURPOSE:To obtain an image forming device in which a light quantity is accurately controlled with one light quantity detection element by providing the light quantity detection element having a switching mechanism near the back side of an irradiating lamp. CONSTITUTION:A light quantity sensor 9 being the light quantity detection element moves to a position shown by a continuous line and detects the light quantity of the irradiating lamp 11 which is started to be energized through a path shown by an arrow C. As soon as the light quantity of the lamp 11 attains a certain necessary light quantity, the sensor 9 is moved to a position shown by a dotted line by turning on a solenoid 10. Then, an original platen 14 and an original pressure plate 15 are also moved to a copying start position which is a point H in a figure. Just before the sensor 9 is moved to the position shown by the dotted line, a microcomputer 30 performs constant-current control to the lamp 11 with necessary light quantity and sufficient current value until the sensor 9 returns to the position shown by the continuous line again so that the lamp 11 may keep the necessary light quantity. |
