Charging device, process cartridge and image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorsHarumi Ishiyama, Yasunori Chigono, Jun Hirabayashi
Life of this patent
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Abstract
A charging device, suitable for use in an electrophotographic image forming apparatus, is formed of an object to be charged, and a roller-shaped charging member disposed in contact with the object via electroconductive particles and supplied with a voltage to charge the objects. The charging member has a surface layer including an elastic foam and is moved with a surface speed difference relative to the object. The charging member has surface cavities having an average diameter of 5 to 150 μm and occupying an area percentage of 50 to 90%. An image forming apparatus and a process cartridge therefor including the charging device are also provided.
Claims37
A charging device, including:
- an object to be charged, and a roller-shaped charging member disposed in contact with the object via electroconductive particles and adapted to be supplied with a voltage to charge the object, the charging member having a surface layer comprising an elastic foam and being adapted to be moved with a surface speed difference relative to the object,
- wherein the charging member has surface cavities having an average diameter of 5 to 150 μm and occupying an area percentage of 50 to 90%.
A process cartridge, comprising an electrophotographic photosensitive member and a charging device including a roller-shaped charging member and integrally supported to form a cartridge which is detachably mountable to a main assembly of an image forming apparatus, wherein
- the charging device is disposed in contact with the photosensitive member via electroconductive particles and supplied with a voltage to charge the photosensitive member,
- the charging member has a surface layer comprising an elastic foam and is moved with a surface speed difference relative to the photosensitive member,
- wherein the charging member has surface cavities having an average diameter of 5 to 150 μm and occupying an area percentage of 50 to 90%.
An image forming apparatus, comprising an electrophotographic photosensitive member, a charging device including a charging member disposed in contact with the photosensitive member via electroconductive particles and supplied with a voltage to charge the photosensitive member, exposure means for exposing the photosensitive member to light to form an electrostatic latent image on the photosensitive member, developing means for developing the electrostatic latent image with a developer to form a toner image on the photosensitive member, and transfer means for transferring the toner image onto a transfer receiving material, wherein
- the charging member has a surface layer comprising an elastic foam and is moved with a surface speed difference relative to the photosensitive member,
- wherein the charging member has surface cavities having an average diameter of 5 to 150 μm and occupying an area percentage of 50 to 90%.
Dependencies are inferred from the claim text.