IMAGE FORMING APPARATUS

• US 20100260509A1
• Filed: 06/28/2010
• Published: 10/14/2010
• Est. Priority Date: 03/12/2003
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Tec Corporation (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Tec Corporation (Toshiba Corporation)
• Inventors: Aoki, Shinji, Watanabe, Takeshi, Hiroki, Masashi, Takahashi, Masashi
• Granted Patent: US 8,237,757 B2
• Time in Patent Office: Days
• US Class Current: 399/40
• CPC Class Codes: G03G 15/0115 and forming a half-tone image
• CPC Class Codes: G03G 15/0173 plural rotations of recording member to produce multicoloured copy, e.g. rotating set of developing units G03G15/0163 takes precedence
• CPC Class Codes: G03G 15/0189 primary transfer to an intermediate transfer belt G03G15/0184 takes precedence
• CPC Class Codes: G03G 15/0194 primary transfer to the final recording medium G03G15/0184 takes precedence
• CPC Class Codes: G03G 15/0415 and means for controlling illumination or exposure
• CPC Class Codes: G03G 21/0064 using the developing unit, e.g. cleanerless or multi-cycle apparatus
• CPC Class Codes: G03G 2215/0119 Linear arrangement adjacent plural transfer points
• CPC Class Codes: G03G 2215/0164 Uniformity control of the toner density at separate colour transfers
• CPC Class Codes: G03G 2215/0602 Developer

Abstract

There is provided a photoreceptor cleanerless image forming apparatus capable of decreasing color mixture or an exposure error due to reverse transfer toner or untransferred toner.

An image forming apparatus 100 according to the present invention comprises four image forming units 100a, 100b, 100c, and 100d configured to be photoreceptor cleanerless in a 4-drum tandem manner. Each image forming unit includes a photoreceptor 103a, 103b, 103c, or 103d, a charger 105a, 105b, 105c, or 105d, an exposure apparatus 106a, 106b, 106c, or 106d, and a developing apparatus 109a, 109b, 109c, or 109d. When exposure intensities Iy, Ic, Im, and Ik are assumed for exposure sources of the exposure apparatuses in the image forming units which form yellow, magenta, cyan, and black images, respectively, the exposure intensities are configured to satisfy conditions of Ik≧Ic≧Im≧Iy and Ik>Iy. This decreases an exposure error (image hysteresis) in an image formed on paper.

Claims

1. A photoreceptor cleanerless image forming apparatus to overlappingly form yellow, magenta, cyan, and black toner images,

wherein said apparatus includes a control section that is configured to decrease color mixture or exposure error based on controlling a volume-based average particle diameter of toner,

wherein said apparatus comprises four photoreceptor cleanerless developing apparatuses to overlappingly form yellow, magenta, cyan, and black toner images;

and

volume-based average particle diameters Pa, Pb, Pc, and Pd are configured to satisfy conditions of Pa≧

Pb≧

Pc≧

Pd and Pa>

Pd, where Pa, Pb, Pc, and Pd indicate volume-based average particle diameters of toners to be developed on a photoreceptor in the order of development.