US 5,430,527 AGranted

Electrophotographic apparatus having cleaning width larger than charging width

AssigneeCanon Kabushiki Kaisha

InventorsAkio Maruyama, Junichi Kishi, Hiroyuki Ohmori, Masami Okunuki

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Abstract

An image forming apparatus has a photosensitive member, a charging device, an image exposure device for exposing the photosensitive member to form a latent image, a developing device for developing the latent image with a toner to form a transferable toner image on the surface of the photosensitive member, a transfer device for transferring the toner image to a transfer material, and a cleaning device for removing a residual toner; the charging device, image exposure device, developing device, transfer device and cleaning device being disposed in the named order along the moving direction of the photosensitive member. The charging device includes an electroconductive member which directly contacts the photosensitive member surface to charge the photosensitive member surface. The electroconductive member forms a nip width with the photosensitive member of at least 0.5 mm and a load per unit contact area between the electroconductive member and photosensitive member is between 0.5-30 g/mm.sup.2. With respect to the longitudinal direction of the photosensitive member, the width of the photosensitive member surface cleaned by the cleaning device is equal to or greater than the width of the photosensitive member surface contacting the electroconductive member.

Claims5

Dependent claims

An image forming apparatus comprising:

a photosensitive member having a laminated photosensitive layer including a charge generation layer and a charge transport layer, said charge generation layer comprising a binder resin and an organic photoconductive material dispersed in said binder resin;
charging means, including an electroconductive member a portion of which is in direct contact with a surface of said photosensitive member, for charging said photosensitive member surface;
image exposure means for exposing said photosensitive member surface to form a latent image;
developing means for developing the latent image with a toner to form a transferable toner image on said photosensitive member surface;
transfer means for transferring the toner image to a transfer material;
and
cleaning means for removing contaminants, including residual toner, from said photosensitive member surface;
said charging means, image exposure means, developing means, transfer means, and cleaning means being disposed in the named order along a moving direction of said photosensitive member;
wherein with respect to a longitudinal direction of said photosensitive member, a width of said photosensitive member surface being cleaned by said cleaning means is larger than a width of the portion of said photosensitive member surface in direct contact with said electroconductive member;
and
wherein the width of the portion of said photosensitive member surface in direct contact with said electroconductive member is larger than the width of an imaging region of said photosensitive member surface, so that said cleaning means is effective to remove contaminants, including residual toner, remaining on the full width of the portion of said photosensitive member surface in direct contact with said electroconductive member, including a marginal region in excess of the imaging region, thereby reducing the possibility of a dielectric breakdown of said photosensitive member at the portion of the photosensitive member surface in direct contact with said electroconductive member;
and
wherein a nip width between said electroconductive member and said photosensitive member is at least 0.5 mm and a load applied therebetween per unit contact area is in a range between 0.5-30 g/mm.sup.2.

10 more elements

An image forming apparatus, comprising:

a photosensitive member having a laminated photosensitive layer including a charge generation layer and a charge transport layer, said charge generation layer comprising a binder resin and an organic photoconductive material dispersed in said binder resin;
charging means, including a charging member a portion of which is in direct contact with a surface of said photosensitive member, for charging said photosensitive member surface;
developing means for developing a latent image formed by exposing said photosensitive member after charging said photosensitive member surface, with a toner to form a transferable toner image on said photosensitive member surface;
cleaning means for removing contaminants, including residual toner, from said photosensitive member surface after transferring the toner image to a transfer material;
said charging means, developing means, and cleaning means being disposed in the named order along a moving direction of said photosensitive member;
wherein with respect to a longitudinal direction of said photosensitive member, a width of said photosensitive member surface being cleaned by said cleaning means is larger than a width of the portion of said photosensitive member surface in direct contact with said charging member;
and
wherein the width of the portion of said photosensitive member surface in direct contact with said charging member is larger than the width of an imaging region of said photosensitive member surface, so that said cleaning means is effective to remove contaminants, including residual toner, remaining on the full width of the portion of said photosensitive member surface in direct contact with said charging member, including a marginal region in excess of the imaging region;
and
wherein a nip width between said charging member and said photosensitive member is at least 0.5 mm and a load applied therebetween per unit contact area is in a range between 0.5-30 g/mm.sup.2.

7 more elements

An image forming apparatus, comprising:

a photosensitive member having a laminated photosensitive layer including a charge generation layer and a charge transport layer, said charge generation layer comprising a binder resin and an organic photoconductive material dispersed in said binder resin;
charging means, including a charging member a portion of which is in direct contact with a surface of said photosensitive member, for charging said photosensitive member surface;
developing means for developing a latent image formed by exposing said photosensitive member after charging said photosensitive member surface, with a toner to form a transferable toner image on said photosensitive member surface;
cleaning means for removing contaminants, including residual toner, from said photosensitive member surface after transferring the toner image to a transfer material;
said charging means, developing means, and cleaning means being disposed in the named order along a moving direction of said photosensitive member;
wherein with respect to a longitudinal direction of said photosensitive member, a width of said photosensitive member surface being cleaned by said cleaning means is larger than a width of the portion of said photosensitive member surface in direct contact with said charging member;
and
wherein the width of the portion of said photosensitive member surface in direct contact with said charging member is larger than the width of an imaging region of said photosensitive member surface, so that said cleaning means is effective to remove contaminants, including residual toner, remaining on the full width of the portion of said photosensitive member surface in direct contact with said charging member including a marginal region in excess of the imaging region, thereby reducing the possibility of a dielectric breakdown of said photosensitive member at the portion of the photosensitive member surface in direct contact with said electroconductive member;
and
wherein a nip width between said charging member and said photosensitive member is at least 0.5 mm and a load applied therebetween per unit contact area is in a range between 0.5-30 g/mm.sup.2.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/263,394Filed 21 Jun 1994 · continuation
Priority: JP 62-16356030 Jun 1987
Granted: 4 Jul 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G03G 21/0005
Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge: for removing solid developer or…
G03G 5/047
Photoconductive layers characterised by having two or more layers or characterised by their composite structure: characterised by the…
G03G 15/0216
By contact, friction or induction, e.g. liquid charging apparatus: by bringing a charging member into contact with the member to be charged, e.g.…
G03G 2215/025
By contact, friction or induction: using contact charging means having lateral dimensions related to other apparatus means, e.g. photodrum,…

Family

Serial212,655Parent of this continuation · filed 28 Jun 1988
Serial555,359Parent of this continuation · filed 18 Jul 1990
Serial839,716Parent of this continuation · filed 24 Feb 1992
Serial137,220Parent of this continuation · filed 18 Oct 1993
US 5,430,527 AThis patent

From the US filing history. Foreign family members aren’t listed.