| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device capable of always forming an image having high image quality by controlling the bias voltage of a developing roller, so as to prevent a change in printing density occurring according to the increase of the number of prints. SOLUTION: A cumulative print number value stored in an EFPROM is read out (S1) and when the exchange of a process unit 7 is not required (S2:NO), a prescribed bias value voltage corresponding to each cumulative print number value is read from developing bias voltage information 80 stored in the EEPROM (S5). Then, a fixed bias voltage is applied to the developing roller (S6). After that, printing is started (S7) and when the rotation of a photoreceptor drum for one print is detected by a photoreceptor drum rotation sensor (S8:YES), the application of a developing bias voltage is stopped (S9). After that, the cumulative print number value is increased by one (S10) and when printing is not completed (S11:NO), a printing operation is continued again. |
