| 摘要 |
PURPOSE:To shorten a potential measurement time greatly by using an LED, which has a short rising and a short breaking time, as a light source for measuring the potential of a photoreceptor. CONSTITUTION:An optical system consisting of an original exposure lamp 46 and a mirror 44 moves forth for original exposure and when it reaches an inversion position, a shielding member 82 is closed to inhibit a drum 47 from being irradiated with light from the lamp 46 and a setting table 54. The LED70 emits intense light for irradiation of light-part light quantity and when the drum 47 turns by a prescribed angle, the LED70 is turned off. At the timing where the part of the drum irradiated as mentioned above comes to an electrometer 67, the potential of the light part is measured and at the timing where the unexposed part comes, the potential of a dark part is measured. On the basis of the measurement results, primary and AN charging currents are correct. Simultaneously with the corrections, the light emission quantity of the LED70 is changed over to the standard light emission quantity, and a standard light-part potential is measured to determine a development bias voltage. Those found values are outputted to a primary charger 51, an AC discharger 69, a developing device 62, and a developing roller 65 respectively to control their operations. |
