Patent ID: 6963715
Filing Date: 2005-11-08
Classification: G03G

Abstract:
1. A color image forming apparatus comprising: a plurality of photoconductors arranged in a line so that their rotary center shafts become parallel with one another and rotating in the peripheral direction, on which electrostatic latent images corresponding to toner images of each color are formed respectively; developing units provided respectively correspondingly to said photoconductors and making said electrostatic latent images formed on said photoconductors visible to form toner images; an endless intermediate transfer member arranged in a contactable state with said photoconductors to run; first bias transfer rollers which are arranged in a loop of said intermediate transfer member correspondingly to each photoconductor, and bring said intermediate transfer member into pressure contact with said photoconductors thereby to transfer the toner images of each color on said photoconductor onto said intermediate transfer member, that is, to perform first bias transfer; a second bias transfer roller which presses a recording medium against said intermediate transfer member thereby to transfer the toner image transferred on said intermediate transfer member onto said recording medium, that is, to perform second bias transfer; and a separation mechanism which, when a maximum print length of an image to be printed on one recording medium is below a length from a transfer point of the first bias transfer located on the most downstream side in the moving direction of said intermediate transfer member to a transfer point of second bias transfer in the moving direction of said intermediate transfer member, separates said photoconductor and said intermediate transfer member from each other during a period after all first bias transfer of the toner image to be transferred on a last recording medium in a first print job has been completed, before second bias transfer onto the last recording medium is started and after second bias transfer onto a recording medium immediately before the last recording medium has been completed.