| 摘要 |
PROBLEM TO BE SOLVED: To reduce the amount of silica to be transferred to an image carrier at the beginning of using a developing device while reducing a difference in wear due to an external additive between an image part and a non-image part on the image carrier when the developing device is used for a long time.SOLUTION: The carrier particle diameter of initial developer stored in developer housing chambers 26, 27 before using a developing device 20 is set to be larger than the carrier particle diameter of developer to be supplied. The amount of free silica is thereby suppressed and the amount of silica to be deposited on a photoreceptor drum 1 is reduced. In developer 33 to be supplied from a supply cartridge 30a, the particle diameter of a magnetic carrier is made to be smaller than that of the initial developer to adjust the amount of free silica which is not attached to toner. The amount of silica to be transferred to a non-image part of the photoreceptor drum is thereby maintained to reduce uneven wear on a surface of a photoreceptor drum when the surface is worn by the silica deposited at the tip of a cleaning blade 6b. |
