| 摘要 |
PURPOSE:To form a high-grade image having a stable image density while reducing a wasteful time by detecting the circumferential temp. of a laser beam source and controlling a current value so that the intensity of the laser beam outputted from a laser beam source becomes stable at a predetermined level corresponding to the detection result. CONSTITUTION:The electrostatic latent image obtained by irradiating a charged photosensitive drum 13 with modulated laser beam LB from a laser diode LD is developed by toner to obtain an image. A predetermined drive current and a threshold current are supplied to the laser diode LD by a drive circuit 11 and a threshold circuit 12 and the circumferential temp. of the laser diode LD is detected by a temp. sensor 15. A control circuit 14 controls the current values supplied from the circuits 11,12 so that the intensity of the laser beam outputted from the laser diode LD becomes stable at a predetermined level capable of footing an electrostatic latent image. As a result, a wasteful time is reduced and a high-grade image containing a medium contrast image can be formed in stable image density. |
