EP0505168A2
Expired / Lapsed
EP
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Colour picture image formation devices
Assignee: Fujitsu Ltd
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Filing: 1992-03-18
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Granted: —
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Expires: 2012-03-18
Abstract
Abstract A colour picture image formation device includes a plurality of image formation sections (P′), each containing a photosensitive body drum (17), a charge unit (18), an exposure unit (19) and a developing unit (20). The image formation sections produce toner picture images of different respective colours. The device also includes an intermediate transfer body (15) for receiving, and superimposing on one another, the toner picture images from the photosensitive body drums (17) of the image formation sections and for transferring the combined toner picture image to recording paper (100). The intermediate transfer body (15) is constructed and connected to permit the potential at its surface to differ at different locations thereon, thereby permitting different primary transfer voltages to be generated, between the transfer body (15) and the photosensitive body drum (17), for the different image formation sections (P′). The transfer section of the intermediate transfer body (15), from which the toner images are transferred to the recording paper (100), can be grounded to permit the secondary transfer voltage to be reduced.
Inventors
- 👤 Shuji C/O Fujitsu Limited Koike
- 👤 Akihiko C/O Fujitsu Limited Ishii
- 👤 Shino C/O Fujitsu Limited Sakai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 06:56
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/01; G03G15/0105; G03G15/0131; G03G15/0142; G03G15/0178; G03G15/0194
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
168 words
A color picture image formation device having a plurality of photosensitive body drums, said device comprising: a plurality of image formation sections, each comprising one of said photosensitive body drums, an electrocharge unit, an exposure unit, and a developing unit for developing a respective color toner image on said photosensitive body drum; an intermediate transfer body for holding toner powder images in a required number of colors, so that said respective color toner images on said photosensitive body drums are transferred, respectively, onto said intermediate transfer body and, after all of the toner picture images have been formed on said intermediate transfer body, the toner picture images thereon are transferred at a recording area onto a recording paper and then fixed thereto by a fixing unit; characterized in that a transfer voltage which should be exerted to the intermediate transfer body can be regulated for respective area corresponding to the respective developing units and moreover said transfer voltage is grounded at a transfer area to said recording area.
Claim 2
Dependent Claim
51 words
A color picture image formation device as described in Claim 1, characterized in that said intermediate transfer bodies are of drum shape and the applicable intermediate transfer drum has a multiple layer construction consisting of an insulation layer, electrode and a voltage application layer from the surface of metallic elementary tube.
Claim 3
Dependent Claim
94 words
A color picture image formation device as described in Claim 2, characterized in that the metallic conductive electrode to be arranged on the insulation layer of said intermediate transfer body drum uses said intermediate transfer body drum which has been split thinly in longitudinal axis direction, a voltage application brush or a grounding brush has been constituted in such that it body get in contact with these metallic conductive electrodes and moreover the width of metallic conductive electrode is thinner than the contact width of photosensitive body drum, transfer roller and intermediate transfer drum.
Claim 4
Dependent Claim
127 words
A color picture image formation device as described in Claim 3, characterized in that, as regards said metallic conductive electrode, electrodes equal to or longer than the depth of said intermediate transfer body drum are arranged in parallel to each other at equal distance before said conductive electrode is to be laid out on the intermediate transfer body drum, both the ends of which are fixed in place by an adhesive tape and the width of said metallic conductive electrode is within 5 mm or shall preferably be from 500 µm to 1 mm, and its thickness is set to be thinner than 2 mm so that it may not get bent or broken even after getting in touch with said voltage application brush or grounding brush.
Claim 5
Dependent Claim
124 words
A color picture image formation device as described in Claim 3, characterized in that long cavities are perforated in width direction into the formation of electrodes of equal distance on a plate for a long metallic conductive electrode whose thickness is less than 2 mm and which is longer than the depth of said intermediate transfer body drum, this cavity is longer than the depth of intermediate transfer body drum, a part of both the ends is tied against the width direction, and both the ends of plate for said metallic conductive electrode are cut off after passing said part of both ends on the insulation layer over said intermediate transfer body drum so that the respective thin metallic conductive electrodes may become individual.
Claim 6
Dependent Claim
107 words
A color picture image formation device as described in Claim 2, characterized in that a pressurization conductive rubber lined on the metallic conductive electrode for intermediate transfer body drum has a volumetric resistivity from 10⁶ to 10¹⁰ Ω·cm or shall preferably be in the order of 10⁶ Ω·cm during its pressuri zation so that there may exist no short circuitry with the transfer roller and of higher than 10¹³ Ω·cm during no pressure application, and no rubber is lined on the intermediate transfer body drum as to the portion corresponding to the width of voltage impressing conductive brush at one end of said intermediate transfer body drum.
Claim 7
Dependent Claim
100 words
A color picture image formation device as described in Claim 1, which in characterized in that, in the primary transfer between the intermediate transfer body drum and the photosensitive body drum, a transfer voltage application conductive brush is arranged to one end of said intermediate transfer body drum at the contact portion between said intermediate transfer body drum and each of photosensitive body drums, and said transfer voltage application conductive brush is laid out at every contact portion between each photosensitive body drum and said intermediate transfer body drum and is longer than the contact portion of both the drums.
Claim 8
Dependent Claim
89 words
A color picture image formation device as described in Claim 7, characterized in that the base material of said transfer voltage application conductive brush is prevented from coming in contact with each photosensitive body drum and moreover an insulation treated base material surface shall be used for said transfer voltage application brush, the voltage being impressed to said transfer voltage application brush can be adjusted in the primary transfer from each of photosensitive body drums so that a favorable transfer may be achieved for every picture image formation units.
Claim 9
Dependent Claim
123 words
A color picture image formation device as described in said Claim 1, which is characterized in that the transfer by roller shall be conducted in the secondary transfer to be transferred from the intermediate transfer body drum to the recording paper, and a conductive brush which is longer over the back and forth in circumferential direction than the contact portion between said roller transfer and said intermediate transfer body drum is installed to the portion where said metallic conductive electrode is exposed to said intermediate transfer drum surface of one end of said intermediate transfer body drum at the portion for the roller transfer to get in touch with said intermediate transfer body drum, with said conductive brush being grounded at all times.
Claim 10
Dependent Claim
51 words
A color picture image formation device as described in Claim 6 which is characterized in that the surface of pressurization conductive rubber lined on said intermediate transfer body drum is covered with a dielectric substance whose thickness if from 80 to 200 µm or shall preferably be set to 100 µm.
Claim 11
Dependent Claim
201 words
A color picture image formation device comprising: a plurality of image formation sections, each comprising a photosensitive means, an electrocharge unit, an exposure unit, and a developing unit for developing a single color toner image on said photosensitive means; an intermediate transfer body for holding toner powder images in a required number of colors, so that said respective color toner images on said photosensitive means are transferred, respectively, onto said intermediate transfer body and, after all of toner picture images have been formed on said intermediated transfer body, the toner picture images thereon are transferred onto a recording paper and then fixed thereto by a fixing unit; and means for exerting a voltage onto said intermediate transfer body for transferring said respective color toner picture images; characterized in that if a "transfer efficiency" is defined as a ratio of the mount of toner of the toner image formed on said intermediate transfer drum with respect to the mount of toner of the toner image formed on on said respective photosensitive means, a transfer efficiency of a first color transferred directly on the intermediate transfer body as a lowermost layer is more than those of the colors other than said first color.
Claim 12
Dependent Claim
48 words
A color picture image formation device as as described in claim 11, wherein a circumferential surface of said intermediate transfer body is coated with a conductive, resilient member having a volume resistivity of 10⁸ to 10¹²Ω·cm and a range of said transfer voltage is 600 to 1200 Volt.
Claim 13
Dependent Claim
29 words
A color picture image formation device as as described in claim 12, wherein said range of transfer voltage exerted by said voltage exerting means if 800 to 1000 Volt.
Claim 14
Dependent Claim
153 words
A colour image-forming device for forming a colour image on a recording medium, which device includes: a plurality of image-formation bodies (17), on which respective different-coloured toner images are produced electrostatically when the device is in use; and an intermediate transfer body (15) moveable relative to the said image-formation bodies (17), and having a working surface that is in contact at different respective locations with the individual image-formation bodies (17), for receiving the respective images from the image-formation bodies in turn so that those images are superimposed upon one another to form a combined colour toner image that is transferred to a recording medium from the said working surface at a recording location; the said intermediate transfer body (15) being constructed and connected to permit the potential of its working surface at each of the said different respective locations to be controlled independently of the potentials at each of the other such locations.
Claim 15
Dependent Claim
29 words
A colour image-forming device as claimed in claim 14, further including means (25) for maintaining the said working surface at ground potential in the vicinity of the recording location.
References Cited (Backward Citations)
No citation records indexed.
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