发明申请
- 专利标题: IMAGE FORMING APPARATUS
- 专利标题(中): 图像形成装置
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申请号: US12537375申请日: 2009-08-07
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公开(公告)号: US20090317139A1公开(公告)日: 2009-12-24
- 发明人: Fumitake HIROBE , Yuichiro TOYOHARA , Tatsuomi MURAYAMA , Akihiro NOGUCHI
- 申请人: Fumitake HIROBE , Yuichiro TOYOHARA , Tatsuomi MURAYAMA , Akihiro NOGUCHI
- 申请人地址: JP Tokyo
- 专利权人: CANON KABUSHIKI KAISHA
- 当前专利权人: CANON KABUSHIKI KAISHA
- 当前专利权人地址: JP Tokyo
- 优先权: JP2005-251658 20050831
- 主分类号: G03G15/01
- IPC分类号: G03G15/01
摘要:
An image forming apparatus includes a developing apparatus for developing an electrostatic image with a developer comprising at least a toner and a first external additive, the developing apparatus including a plurality of developing devices, containing toners different in color or lightness from each other, in which at least two developing devices contain a dark color toner and a light color toner which have an identical hue and different lightnesses and the developing device containing the light color toner is subjected to a developing operation prior to another developing device; a first transfer apparatus for sequentially transferring toner images, which have been developed by the plurality of developing devices, onto an intermediary transfer member; and a second transfer apparatus for transferring the toner images from the intermediary transfer member all together onto a transfer medium The first external additive includes particles having an aspect ratio of not less than 1.0 and not more than 1.5 and a number-average particle size of not less than 0.06 μm and not more than 0.3 μm, and has a coverage thereof with respect to the light color toner larger than that with respect to the dark color toner in a transferred state on the intermediary transfer member.
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