Back to results
US 9,519,238 B2Granted
Image forming apparatus with photoconductor drum preservation
AssigneeCanon Kabushiki Kaisha
InventorsShinji Katagiri, Shuichi Tetsuno, Masaru Ohno
Life of this patent
Estimating the term…
Abstract
An image forming apparatus that adjusts the electric current supplied from a second transfer member to suppress acceleration of abrasion of a photoconductor drum while maintaining the second transfer efficiency at a desired level.
Claims11
An image forming apparatus, comprising:
- a plurality of photoconductors that carry toner images;
- an endless intermediate transfer member that is rotatable and to which the toner images are first-transferred from the plurality of photoconductors;
- a plurality of contact members disposed at positions corresponding to the plurality of photoconductors, the plurality of contact members coming into contact with an inner circumferential surface of the intermediate transfer member;
- a second transfer member that comes into contact with an outer circumferential surface of the intermediate transfer member and second-transfers the toner images from the intermediate transfer member to a transfer medium;
- a stretching member that stretches the inner circumferential surface of the intermediate transfer member;
- a voltage maintenance element connected to the plurality of contact members and the stretching member and maintaining a surface potential of the intermediate transfer member;
- and
- a controller that is operable in a color mode and a monochrome mode, the color mode being a mode in which toner images, first-transferred to the intermediate transfer member from the plurality of photoconductors using an electric current supplied from the second transfer member in a state where all the plurality of photoconductors are in contact with the intermediate transfer member, are second-transferred to a transfer medium, and the monochrome mode being a mode in which a toner image, first-transferred to the intermediate transfer member from only a specific one of the photoconductors using an electric current supplied to the second transfer member in the state where all the plurality of photoconductors are in contact with the intermediate transfer member, is second-transferred to a transfer medium,
- wherein the voltage maintenance element maintains potentials of the plurality of contact members and the stretching member at a predetermined potential when an electric current flows from the second transfer member through the intermediate transfer member and the stretching member at a predetermined electric current or higher,
- wherein a first electric current supplied from the second transfer member to the intermediate transfer member when the controller is operated in the monochrome mode is lower than a second electric current supplied from the second transfer member to the intermediate transfer member when the controller is operated in the color mode, and
- wherein the first electric current is an electric current is higher than or equal to the predetermined electric current.
8 more elements
An image forming apparatus, comprising:
- a plurality of photoconductors that carry toner images;
- an endless intermediate transfer member that is rotatable and to which the toner images are first-transferred from the plurality of photoconductors;
- a plurality of contact members disposed at positions corresponding to the plurality of photoconductors, the plurality of contact members coming into contact with an inner circumferential surface of the intermediate transfer member;
- a second transfer member that comes into contact with an outer circumferential surface of the intermediate transfer member and second-transfers the toner images from the intermediate transfer member to a transfer medium;
- a stretching member that stretches the inner circumferential surface of the intermediate transfer member;
- a voltage maintenance element connected to the plurality of contact members and the stretching member and maintaining a surface potential of the intermediate transfer member;
- and
- a controller that is operable in a first image formation mode and a second image formation mode, the first image formation mode being a mode in which toner images are second-transferred from the intermediate transfer member to a transfer medium at a first image formation speed, and the second image formation mode being a mode in which toner images are second-transferred from the intermediate transfer member to a transfer medium at a second image formation speed lower than the first image formation speed,
- wherein an electric current supplied from the second transfer member to the intermediate transfer member when the controller is operated in the second image formation mode is lower than an electric current supplied from the second transfer member to the intermediate transfer member when the controller is operated in the first image formation mode,
- wherein the voltage maintenance element maintains potentials of the plurality of contact members and the stretching member at a predetermined potential when an electric current flows from the second transfer member through the intermediate transfer member and the stretching member at a predetermined electric current or higher, and
- wherein an absolute value of the electric current supplied from the second transfer member to the intermediate transfer member when the controller is operated in the second image formation mode is equal to an absolute value of the predetermined electric current.
8 more elements
An image forming apparatus, comprising:
- a plurality of photoconductors that carry toner images;
- an endless intermediate transfer member that is rotatable and to which the toner images are first-transferred from the plurality of photoconductors;
- a contact member disposed at a position corresponding to the plurality of photoconductors, the contact member coming into contact with an inner circumferential surface of the intermediate transfer member;
- a second transfer member that comes into contact with an outer circumferential surface of the intermediate transfer member and second-transfers the toner images from the intermediate transfer member to a transfer medium;
- a stretching member that stretches the inner circumferential surface of the intermediate transfer member;
- a voltage maintenance element connected to the contact member and the stretching member and maintaining a surface potential of the intermediate transfer member;
- and
- a controller that is operable in a color mode and a monochrome mode, the color mode being a mode in which toner images, first-transferred to the intermediate transfer member from the plurality of photoconductors using an electric current supplied from the second transfer member in a state where all the plurality of photoconductors are in contact with the intermediate transfer member, are second-transferred to a transfer medium, and the monochrome mode being a mode in which a toner image, first-transferred to the intermediate transfer member from only a specific one of the photoconductors using an electric current supplied to the second transfer member in the state where all the plurality of photoconductors are in contact with the intermediate transfer member, is second-transferred to a transfer medium,
- wherein the controller performs control so that a first electric current amount, which is an amount of an electric current supplied from the second transfer member to the intermediate transfer member in a case where the monochrome mode is executed, is smaller than a second electric current amount, which is an amount of an electric current supplied from the second transfer member to the intermediate transfer member in a case where the color mode is executed.
6 more elements
Dependencies are inferred from the claim text.