Developing device and process unit and image forming apparatus incorporating same
AssigneeRicoh Company, Ltd.
InventorsTetsumaru Fujita, Ryuji Inoue, Rie Mitani
Life of this patent
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Abstract
A developing device includes a toner bearer including a surface in which multiple recesses having a cross-sectional void rate of 50% or smaller are formed, a toner supply member to supply toner to the toner bearer, and a developer regulator disposed facing or in contact with the toner bearer and including a bent tip portion. The toner bearer has a surface roughness Ra within a range from 1.0 μm to 2.0 μm, and a surface area ratio within a range from 2.0 to 4.0. The developing device uses polymerized toner having a weight average particle diameter of 8.0 μm or smaller and an average circularity of 0.98 or greater.
Claims7
A developing device comprising:
- a toner bearer including a surface in which multiple recesses having a cross-sectional void rate of 50% or smaller are formed, the toner bearer having a surface roughness Ra within a range from 1.0 μm to 2.0 μm and a surface area ratio within a range from 2.0 to 4.0;
- a toner supply member to supply toner to the toner bearer;
- and
- a developer regulator disposed facing or in contact with the toner bearer to adjust a layer thickness of toner carried on the toner bearer, the developer regulator including a bent tip portion,
- wherein the toner is polymerized toner having a weight average particle diameter of 8.0 μm or smaller and an average circularity of 0.98 or greater.
A process unit removably installed in an image forming apparatus, the process unit comprising:
- a latent image bearer on which a latent image is formed;
- and
- a developing device to develop the latent image, housed in a common unit casing together with the latent image bearer,
- the developing device comprising:
- a toner bearer including a surface in which multiple recesses having a cross-sectional void rate of 50% or smaller are formed, the toner bearer having a surface roughness Ra within a range from 1.0 μm to 2.0 μm and a surface area ratio within a range from 2.0 to 4.0;
- a toner supply member to supply toner to the toner bearer;
- and
- a developer regulator disposed facing or in contact with the toner bearer to adjust a layer thickness of toner carried on the toner bearer, the developer regulator including a bent tip portion to adjust a toner conveyance amount on the toner bearer,
- wherein the toner is polymerized toner having a weight average particle diameter of 8.0 μm or smaller and an average circularity of 0.98 or greater.
An image forming apparatus comprising:
- a latent image bearer;
- a latent image forming unit to form a latent image on the latent image bearer;
- and
- a developing device to develop the latent image bearer,
- the developing device comprising:
- a toner bearer including a surface in which multiple recesses having a cross-sectional void rate of 50% or smaller are formed, the toner bearer having a surface roughness Ra within a range from 1.0 μm to 2.0 μm and a surface area ratio within a range from 2.0 to 4.0;
- a toner supply member to supply toner to the toner bearer;
- and
- a developer regulator disposed facing or in contact with the toner bearer to adjust a layer thickness of toner carried on the toner bearer, the developer regulator including a bent tip portion to adjust a toner conveyance amount on the toner bearer,
- wherein the toner is polymerized toner having a weight average particle diameter of 8.0 μm or smaller and an average circularity of 0.98 or greater.
Dependencies are inferred from the claim text.