PURPOSE: To always obtain an appropriate picture density by correcting the value of a voltage impressed on a main charger based on data, which is obtained by comparing a picture density with respect to an reference original with a prescribed picture density, when copying operation is carried out an appropriate number of times.
CONSTITUTION: When the copying operation is carried out the appropriate number of times, the picture density of a toner picture with respect to the reference original is calculated based on data detected by an optical detector 2. This picture density of the toner picture on a photosensitive body with respect to the reference original is compared with the prescribed picture density previously determined. The value of the voltage impressed on the main charger 4 is corrected based on this compared data. Thus, even when deterioration and change in characteristics arise in the main charger of its self and the photosensitive body of its self, an appropriate picture density can be always obtained.
NISHINO TOSHIO
YOSHIDA WATARU
| JPS63148272A | 1988-06-21 | |||
| JPS60143361A | 1985-07-29 |