| 摘要 |
PROBLEM TO BE SOLVED: To provide a color image forming apparatus which can enhance the recycle efficiency of black developer high in use frequency by recovering the black developer without being color-mixed in a color image forming process, and can shorten the reduce printing time in monochrome image formation. SOLUTION: Toner images formed on YCM image carriers 1Y, 1C, and 1M are superposed and transferred to an intermediate transfer belt 6. A black toner image formed by an image carrier 1B is directly transferred to transfer paper conveyed by the transfer paper conveying belt 8 of a recording medium transfer means 15. Subsequently, the toner images superposed on the intermediate transfer belt 6 are transferred to the transfer paper by a secondary transfer roller 28. When a monochrome image is formed, the secondary transfer roller 28 is operated by a contact/separation mechanism, not shown, the transfer paper conveying belt 8 is separated from the intermediate transfer belt 6, and only the recording medium transfer means 15 is operated to transfer the black toner image. COPYRIGHT: (C)2009,JPO&INPIT
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