| 摘要 |
PURPOSE:To output a tone similar to a general white-and-black picture by providing an exposure and electrifying part which compensates the variance of sensitivity around a photosensitive drum. CONSTITUTION:The sensitive variance compensating exposure and electrifying part is provided between an eraser 4 and a main electrifier 3. This exposure and electrifying part consists of a compensating electrifier 1 and a compensating exposure lamp 2, and the compensating electrifier 1 is so combined that the light of the compensating exposure lamp 2 passes it, and the compensating electrifier 1 has a polarity opposite to that of the main electrifier 3 and electrifies a high-sensitivity part of a photosensitive drum 5 with a small absolute value and electrifies a low-sensitivity part with a large absolute value. Main electrification of the main electrifier 3 is performed with a constant current, and the potential is high in the high-sensitivity part and is low in the low-sensitivity part. This potential of the small absolute value is higher than the minimum value of the potential for printing. With respect to exposure, the wavelength is equal to that of exposure for printing and the quantity of light is so set that the charging voltage of the opposite polarity is reduced to an about half. |
