EP0515053A2
Expired / Lapsed
EP
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Colour electrophotographic method and apparatus employed therefor
Assignee: Panasonic Holdings Corp
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Filing: 1992-04-30
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Granted: —
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Expires: 2012-04-30
Abstract
Abstract A colour electrophotographic apparatus includes a plurality of image forming units (25) each including a photoreceptor (27) and a corona charger (28), and using toner (31). In the apparatus, the image forming units (25) are arranged to be displaceable, with respect to an exposure position of an exposure device (24) and a transfer position of a transfer paper holding member (38) being fixed. During image formation, the image forming units (25) are moved to a predetermined position, and the obtained colour image is transferred onto paper sheet on the transfer paper holding member (38). Each of the image forming units (25) has a first image forming position confronting the transfer paper holding member, and a second image forming position different from the first image forming position. In a colour electrophotographic method of the present invention, when the time of use of each photoreceptor (27) for each single colour image in a colour image forming process is represented by T, and the time for electrostatically resting each photoreceptor (27) until the next use of the photoreceptor (27) is denoted by t , a step in the relation of T<t is repeated during the colour image formation. By this electrophotographic arrangement, a compact colour electrophotographic apparatus simple in construction may be obtained, with a high speed operation during a single colour image formation, and favourable nature for maintenance. Furthermore, by the apparatus of the present invention, stable images may be obtained even during continuous use, without fatigue of the photoreceptor and undesirable temperature rise.
Inventors
- 👤 Hajime Yamamoto
- 👤 Hiroshi Terada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 06:13
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/01; G03G15/0105; G03G15/0126; G03G15/0121; G03G15/0142; G03G15/0178; G03G15/0194; G03G2215/00; G03G2215/01; G03G2215/0103; G03G2215/0109; G03G2215/0112; G03G2215/0116
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
111 words
A color electrophotographic apparatus which comprises a plurality of movable image forming units each having at least a photosensitive member and a developing unit, a moving means for displacing the respective image forming units in turn, to the same image forming position during color image formation, a transfer paper holding member for holding transfer paper so as to transfer toner image formed on said photosensitive member onto the transfer paper, and a single exposure device, the respective developing units of said image forming units having toner in a plurality of colors, with a transfer position of said transfer paper holding member and the exposure position of said exposure device being fixed.
Claim 2
Dependent Claim
100 words
A color electrophotographic apparatus as claimed in Claim 1, wherein each of said image forming units has the photosensitive member adapted to move, with a fixed magnet enclosed therein, and a magnetic developing material, and also, includes a toner hopper containing the magnetic developing material and located in a position confronting said photosensitive member so as to cause the magnetic developing material to be magnetically attracted onto the surface of said photosensitive member for adhesion thereto, and a collecting roller for collecting unnecessary developing material in a position confronting the photosensitive member for visualizing the image on said photosensitive member.
Claim 3
Dependent Claim
26 words
A color electrophotographic apparatus as claimed in Claim 2, wherein said magnetic developing material is of a dual-component developing material composed of magnetic carrier and toner.
Claim 4
Dependent Claim
22 words
A color electrophotographic apparatus as claimed in Claim 2, wherein said magnetic developing material for black is of a magnetic mono-component toner.
Claim 5
Dependent Claim
19 words
A color electrophotographic apparatus as claimed in Claim 2, wherein an A.C. voltage is applied to said collecting roller.
Claim 6
Dependent Claim
95 words
A color electrophotographic apparatus which comprises a plurality of movable image forming units each having at least a photosensitive member and a developing unit, a transfer paper holding member for holding transfer paper so as to transfer toner image onto the transfer paper, and an exposure means, with the respective developing units of said image forming units having toner in a plurality of colors each of said image forming units having a first image forming position confronting said transfer paper holding member, and a second image forming position different from said first image forming position.
Claim 7
Dependent Claim
206 words
A color electrophotographic apparatus which comprises a plurality of movable image forming units each having at least a photosensitive member and a developing unit, a transfer paper holding member for holding transfer paper so as to transfer toner image onto the transfer paper, and an exposure means, with the respective developing units of said image forming units having toner in a plurality of colors, said color electrophotographic apparatus including a color mode and a single color mode, and a moving means of said image forming units so controlled as to displace said image forming units in turn, to a first image forming position during said color mode, whereby, after forming an electrostatic latent image on the photosensitive member of said image forming unit by the exposure means and developing said electrostatic latent image by toner, toner images of the respective colors are successively transferred onto the paper sheet held on the transfer paper holding member to form the color image on the transfer paper, and, to displace the predetermined image forming unit to a second image forming position during said single color mode, with the toner image in the single color developed thereat being transferred onto the paper sheet without employing said transfer paper holding member.
Claim 8
Dependent Claim
145 words
A color electrophotographic apparatus which comprises a plurality of movable image forming units each having at least a photosensitive member and a developing unit, a transfer paper holding member for holding transfer paper so as to transfer toner image onto the transfer paper, and an exposure means, with the respective developing units of said image forming units having toner in a plurality of colors, each of said image forming units having a first image forming position confronting said transfer paper holding member, and a second image forming position spaced from said transfer paper holding member, said exposure means being arranged to be changed over between a first state acting on the image forming unit at said first image forming position during the color mode, and a second state acting on the image forming unit at said second image forming position during the single color mode.
Claim 9
Dependent Claim
159 words
A color electrophotographic apparatus which comprises a plurality of movable image forming units each having at least a photosensitive member and a developing unit, a transfer paper holding member for holding transfer paper so as to transfer toner image onto the transfer paper, and a paper feeding means for feeding the paper for transfer to an image forming portion, with the respective developing units of said image forming units having toner in a plurality of colors, each of said image forming units having a first image forming position confronting said transfer paper holding member, and a second image forming position spaced from said transfer paper holding member, said paper feeding means being arranged to be changed over between a first state for feeding the paper to said transfer paper holding member during the color mode, and a second state for feeding the paper to the image forming unit at said second image forming position during the single color mode.
Claim 10
Dependent Claim
186 words
A color electrophotographic apparatus which comprises a plurality of image forming units each having at least a photosensitive member and a developing unit, a transfer paper holding member for holding transfer paper so as to transfer toner image onto the transfer paper, and a single exposure device, the respective developing units of said image forming units having toner in a plurality of colors with a transfer position of said transfer paper holding member and the exposure position of said exposure device being fixed, said color electrophotographic apparatus further including a moving means of said image forming units so controlled as to rotate the group of said image forming units on the whole and to displace said image forming units in turn, to the same image forming position during the color image formation, whereby, after forming an electrostatic latent image on the photosensitive member of said image forming unit by said exposure device and developing said electrostatic latent image by color toner, the toner images are transferred onto the paper sheet held on the transfer paper holding member to form the color image on the transfer paper.
Claim 11
Dependent Claim
98 words
A color electrophotographic apparatus as claimed in Claim 10, wherein each of said image forming units has the photosensitive member adapted to move, with a fixed magnet enclosed therein, and a magnetic developing material, and also, includes a toner hopper containing the magnetic developing material in a position confronting said photosensitive member so as to cause the magnetic developing material to be magnetically attracted onto the surface of said photosensitive member for adhesion thereto, and a collecting roller for collecting unnecessary developing material in a position confronting the photosensitive member for visualizing the image on said photosensitive member.
Claim 12
Dependent Claim
161 words
A color electrophotographic apparatus which comprises a plurality of movable image forming units each having at least a photosensitive member and a developing unit, a transfer image holding member for holding transfer image so as to transfer toner image, and a single exposure device, the respective developing units of said image forming units having toner in a plurality of colors, with a transfer position of said transfer image holding member and the exposure position of said exposure device being fixed, said color electrophotographic apparatus further including a moving means of said image forming units so controlled as to displace said image forming units in turn, to the same image forming position during the color image formation whereby, after forming an electrostatic latent image on the photosensitive member of said image forming unit by said exposure device and developing said electrostatic latent image by toner, the toner images are transferred onto said transfer image holding member to form the color image thereon.
Claim 13
Dependent Claim
89 words
A color electrophotographic method which comprises the steps of forming respective single color images in a plurality of colors, and combining said respective single color images to form a color image, wherein, when time for using the photosensitive member during said respective single color image forming step for the color image formation is represented by T, and time for electrostatically resting the photosensitive member up to the next use of said photosensitive member, by t, a step in a relation of T<t is repeated to form the color image.
Claim 14
Dependent Claim
48 words
A color electrophotographic method for continuously forming the same image for a plurality of times, which comprises the steps of forming the color by combining a plurality of single color images, and electrostatically resting a photosensitive member employed therefor during continuous use thereof for the color image formation.
Claim 15
Dependent Claim
55 words
A color electrophotographic method which comprises the steps of forming respective single color images in a plurality of colors, and combining said respective single color images to form a color image, wherein time for electrostatically resting a photosensitive member employed therefor is provided between said respective single color image formations in the plurality of colors.
References Cited (Backward Citations)
No citation records indexed.
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