| 摘要 |
<P>PROBLEM TO BE SOLVED: To shorten the press-contact period of a developing roller and a supply roller and to realize high-quality image formation by switching and operating a developing cartridge to be used as much as possible in loading a plurality of developing cartridges in which the same color toner is stored in order to realize long-term image formation which does not require the frequent replenishing work of the toner. <P>SOLUTION: In the image forming apparatus, the toner is stuck to an electrostatic latent image on the surface of a photoreceptor drum 32 so as to develop the image by rotating the developing roller 37b and the supply roller in a press-contact state only at a developing position where a plurality of developing cartridges 37 housed in a developing rotary unit 33 and storing the same color toner are opposed to the drum 32. Every time an engine control part receives a printing instruction, it rotates the unit 33 so as to switch to the cartridge 37 whose elapsed time after finishing previous developing operation is the longest. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
