| 摘要 |
PURPOSE:To make subtle density adjustment possible, by switching the electric power quantity for the lamp adjusted by a key to the adjustment quantity for standard light-exposure at a prescribed time after the end of copying and by inhibiting light quantity adjustment during light-exposure. CONSTITUTION:Variable resistor VR2 is provided for setting a light-exposure quantity and is arranged in the operation panel part of the copying machine as a light-exposure dial, and variable resistor VR3 is so operated that it becomes a proper value for the center value of variable resistor VR2 to perform fine adjustment of the light-exposure quantity, and further, variable resistor VR1 is operated to determine an adjustable voltage range by variable resistor VR2. Then, after the end of copying, the electric power quantity for lamp LA is switched to the adjustment quantity for standard light-exposure at a prescribed time, and further, light quantity adjustment is inhibited during light-exposure. Filter 3 to cut infrared rays is inserted to the light path of the optical system to prevent the bad influence upon the copied image dependent upon change of the spectral distribution characteristic of the light source for change of brightness of the light source. |
