| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technique for automatically optimizing a primary transfer bias according to characteristics of individual belts for primary transfer without adding any special hardware to a color image forming device. <P>SOLUTION: A part of a photosensitive belt 1 is electrostatically charged by a primary electrostatic charger 2 to -600 V and rotated up to a primary transfer nip 32 and a primary transfer bias +300 V is applied in timing to the entry of an electrostatically charged part into the primary transfer nip 32, thereby reducing negative electrostatic charges. After the photosensitive belt 1 is cleaned and electrostatically discharged, an electrometer 33 measures the potential and the primary transfer bias is raised by +100 V repeatedly up to +1,100 V or until the potential of the photosensitive belt 1 decreases below -50 V. The primary transfer bias and potential variation data on the photosensitive belt before and after the primary transfer are collated with potential variation of the photosensitive belt before and after the primary transfer and transfer rate data which are previously obtained to obtain a primary transfer voltage with which the maximum transfer rate is obtained. <P>COPYRIGHT: (C)2004,JPO |
