EP0526137A2
Expired / Lapsed
EP
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Electrophotographic method and apparatus employed therefor
Assignee: Panasonic Holdings Corp
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Filing: 1992-07-24
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Granted: —
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Expires: 2012-07-24
Abstract
Abstract An electrophotographic method and an apparatus employed for effecting the method, in which a photoreceptor drum having a fixed magnet member (MIR) in it is employed. After forming an electrostatic latent image on the surface of the photoreceptor drum (P1), the photoreceptor surface is brought into contact with the magnetic developing material (O) within a developing material hopper (H1) so as to attract the developing material onto the surface of the photoreceptor drum by magnetic force. When the photoreceptor surface further passes an electrode roller (R1), the toner remains only at the image portion for development into a visible toner image. As a force for removing the magnetic developing material from the photoreceptor surface, a resultant force of a magnetic force connecting the photoreceptor drum and the electrode roller and an electrostatic force connecting the photoreceptor drum and the electrode roller, is employed. Thus, the present invention provides the novel electrophotographic method and the apparatus for executing the method, which is simple in construction and a compact in size, and capable of providing images with a high resolution.
Inventors
- 👤 Hajime Yamamoto
- 👤 Hiroshi Terada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 05:45
CPC Classifications
B; B82; B82Y; B82Y15/00; G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/095; G03G15/75; G03G15/751; G03G2215/00; G03G2215/06; G03G2215/0602; G03G2215/0604; G03G2215/0614; G03G2215/0621; G03G2215/0634; G03G2215/0636; G03G2215/0639
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
146 words
An electrophotographic method which comprises a first step for causing a magnetic developing material to adhere onto a surface of an electrostatic latent image holding member by moving the electrostatic latent image holding member enclosing therein a fixed magnet means so as to pass through a developing material hopper containing therein the magnetic developing material, and a second step for removing unnecessary magnetic developing material from the surface of said latent image holding member by confronting said latent image holding member with an electrode roller provided through a gap with respect to the surface of said latent image holding member, wherein a force required for removing the magnetic developing material from the surface of said latent image holding member is said second step is of a resultant force of a magnetic force and an electrostatic force connecting said latent image holding member with said electrode roller.
Claim 2
Dependent Claim
148 words
An electrophotographic method which comprises a first step for causing a magnetic developing material to magnetically adhere onto a surface of an electrostatic latent image holding member by moving the latent image holding member enclosing therein a fixed magnet A so as to pass through a developing material hopper containing therein the magnetic developing material, and a second step for removing unnecessary magnetic developing material from the surface of said latent image holding member by confronting said latent image holding member with an electrode roller having therein another magnet B of a polarity opposite to that of said fixed magnet A and provided through a gap with respect to the surface of said latent image holding member, said electrode roller being applied with an A.C. voltage in said second step so as to collect the unnecessary magnetic developing material on the surface of said latent image holding member.
Claim 3
Dependent Claim
174 words
An electrophotographic method which comprises a charging step for successively charging a surface of an electrostatic latent image holding member by moving said latent image holding member enclosing therein a fixed magnet means, a latent image forming step for forming an electrostatic latent image on the surface of said latent image holding member, a developing material supply step for magnetically attracting and adhering a magnetic developing material onto the surface of said latent image holding member by passing said latent image holding member through a developing material hopper containing therein the magnetic developing material, and a developing step for subjecting the electrostatic latent image to reversal development by confronting the surface of said latent image holding member with an electrode roller provided through a gap with respect to the surface of said latent image holding member and applied with a voltage, wherein timing of the voltage impression for effecting the reversal development in said developing step is set at passing of the developing step for the charged region of said latent image holding member.
Claim 4
Dependent Claim
101 words
An electrophotographic method as claimed in Claim 3, wherein the voltage to be applied to said electrode roller is of an A.C. voltage superposed with a D.C. voltage, and the A.C. voltage superposed with the D.C. voltage which will not subject the electrostatic latent image holding member to development is applied at the time of passing of an uncharged region of said latent image holding member, while the A.C. voltage superposed with the D.C. voltage which is suitable for development of the latent image is applied at the time of passing of the charged region of said latent image holding member.
Claim 5
Dependent Claim
116 words
An electrophotographic apparatus which comprises an electrostatic latent image holding member enclosing a fixed magnet therein and adapted to be moved, a supply means for supplying magnetic developing material onto a surface of said latent image holding member, an electrode roller disposed at a position confronting at least part of said fixed magnet, through a predetermined gap with respect to the surface of said latent image holding member, and adapted to rotate in its advance in a direction opposite to the direction of rotation of said electrode roller, and further , a voltage impressing means for impressing a voltage for removing toner at a non-image portion on said latent image holding member, to said electrode roller.
Claim 6
Dependent Claim
17 words
An electrophotographic apparatus as claimed in Claim 5, wherein said electrode roller is of a magnetic member.
Claim 7
Dependent Claim
23 words
An electrophotographic apparatus as claimed in Claim 5, wherein said electrode roller is of a non-magnetic roller having a magnet means enclosed therein.
Claim 8
Dependent Claim
26 words
An electrophotographic apparatus as claimed in Claim 5, wherein said magnetic developing material is of a dual- component magnetic developing material composed of toner and carrier.
Claim 9
Dependent Claim
20 words
An electrophotographic apparatus as claimed in Claim 5, wherein said magnetic developing material is of a mono-component magnetic developing material.
Claim 10
Dependent Claim
171 words
An electrophotographic apparatus which comprises an electrostatic latent image holding member enclosing a fixed magnet means therein and adapted to be moved, a latent image forming means for forming an electrostatic latent image on said latent image holding member, a developing material hopper confronting the surface of said latent image holding member and containing a magnetic developing material therein so as to cause the developing material to be magnetically attracted and adhere onto the surface of said latent image holding member by an action of said fixed magnet means, and an electrode roller provided through a gap with respect to the surface of said latent image holding member so as to be applied with an A.C. voltage, and adapted to rotate in a direction of advance opposite to that of said latent image holding member, wherein position of magnetic poles of said magnet means within said latent image holding member is at an upstream side from the closest position of said latent image holding member with respect to said electrode roller.
Claim 11
Dependent Claim
225 words
An electrophotographic apparatus which comprises an electrostatic latent image holding member enclosing a fixed magnet A therein and adapted to be moved, a latent image forming means for forming an electrostatic latent image on said latent image holding member, a developing material hopper confronting the surface of said latent image holding member and containing a magnetic developing material therein so as to cause the developing material to be magnetically attracted and adhere onto the surface of said latent image holding member by an action of said fixed magnet A, and an electrode roller for removing toner at a non-image portion on said latent image holding member, wherein said electrode roller is constituted by a non-magnetic member enclosing therein another magnet B having polarity opposite to that of said magnet A, position of magnetic poles of said magnet means within said latent image holding member is at an upstream side from the closest position of said latent image holding member with respect to said electrode roller, with position of magnetic poles of said magnet B within said electrode roller being at the closest position between said latent image holding member and said electrode roller or at a downstream side therefrom, and said electrode roller is provided through a gap with respect to the surface of said latent image holding member, and applied with an A.C. voltage.
Claim 12
Dependent Claim
165 words
An electrophotographic apparatus which comprises an electrostatic latent image holding member enclosing a fixed magnet means therein and adapted to be moved, a latent image forming means for forming an electrostatic latent image on said latent image holding member, a developing material hopper confronting the surface of said latent image holding member and containing a magnetic developing material therein so as to cause the developing material to be magnetically attracted and adhere onto the surface of said latent image holding member by an action of said fixed magnet means, and an electrode roller for removing toner at a non-image portion on said latent image holding member, wherein said electrode roller provided through a gap with respect to the surface of said latent image holding member is applied with an A.C. voltage, and adapted to rotate in its advancing direction opposite to that of said latent image holding member, with its moving speed being equal to or slower than that of said latent image holding member.
Claim 13
Dependent Claim
158 words
An electrophotographic apparatus which comprises an electrostatic latent image holding member enclosing a fixed magnet means therein and adapted to be moved, a charging means for charging said latent image holding member, a latent image forming means for forming an electrostatic latent image on said latent image holding member, a developing material hopper confronting the surface of said latent image holding member and containing a magnetic developing material therein so as to cause the developing material to be magnetically attracted and adhere onto the surface of said latent image holding member by an action of said fixed magnet means, and an electrode roller provided through a gap with respect to the surface of said electrostatic latent image holding member so as to be applied with an A.C. voltage for reversal development of said electrostatic latent image, charging width of said latent image holding member by said charging means being larger than magnetizing width of said fixed magnet means.
Claim 14
Dependent Claim
157 words
An electrophotographic apparatus which comprises an electrostatic latent image holding member enclosing a fixed magnet means therein and adapted to be moved, a latent image forming means for forming an electrostatic latent image on said latent image holding member, a developing material hopper confronting the surface of said latent image holding member and containing a magnetic developing material therein so as to cause the developing material to be magnetically attracted and adhere onto the surface of said latent image holding member by an action of said fixed magnet means, and an electrode roller provided through a gap with respect to the surface of said latent image holding member so as to be applied with an A.C. voltage, and adapted to rotate in a direction of advance opposite to that of said latent image holding member, said fixed magnet means having the maximum flux density larger than 300 gauss on the surface of said latent image holding member.
Claim 15
Dependent Claim
144 words
An electrophotographic apparatus which comprises an electrostatic latent image holding member enclosing a fixed magnet means therein and adapted to be moved, a developing material hopper confronting the surface of said latent image holding member and containing a magnetic developing material therein so as to cause the developing material to be magnetically attracted and adhere onto the surface of said latent image holding member by an action of said fixed magnet means, and a rotatable electrode roller provided through a gap with respect to the surface of said latent image holding member so as to be applied with a voltage for collecting unnecessary developing material on said latent image holding member, said developing material hopper having a width larger than 5mm at its portion confronting the surface of said latent image holding member in the direction of movement of said latent image holding member.
References Cited (Backward Citations)
No citation records indexed.
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