| 摘要 |
PURPOSE:To obtain stable image quality by adjusting the contrast of the saturated potentials of a bright part and dark part, then measuring the surface potential of a photoreceptor and determining the exposure of the original. CONSTITUTION:While voltage is being outputted to primary and secondary charger, the quantity of light of an exposure lamp 11 is set at an initial value. This is outputted to a D/A converter 24, and detection of surface potential and checking of whether the potential is a prescribed value or not are repeated. At this time, a CPU23 is kept ready to accept interruption, and in every time when a clock pulses enters, that is, in every time when a photoreceptor rotates by 1 deg., the quantity of light of an exposure lamp is lowered. When the surface potential attains a prescribed value, the clock pulses CK of the quantity equal to the photoreceptor angle between an electrometer and a secondary charger are applied to an initial value of the quantity of light. Thereby, the same quantity of light as the quantity of light irradiated to the part where the surface potential attained the prescribed value is irradiated to the photoreceptor. |
