Developing roller, toner and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9851656-B2
Application number	US-201615072689-A
Country	US
Kind code	B2
Filing date	Mar 17, 2016
Priority date	Mar 18, 2015
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A developing roller includes a conductive axis body; a conductive elastic layer overlying the conductive axis body; and a toner bearing layer overlying the conductive elastic layer and having a surface dispersed with particles having an average particle diameter of from 11 nm to 40 nm. The rotary torque is from 2.5 N to 3.5 N.

First claim

What is claimed is:

1. A developing roller, comprising:
a conductive axis body;
a conductive elastic layer overlying the conductive axis body; and
a toner bearing layer overlying the conductive elastic layer and having a surface dispersed with particles having an average particle diameter of from 11 nm to 40 nm,
wherein a rotary torque of the developing roller is from 2.5 N to 3.5 N when the developing roller is rotated at 180 rpm, and
wherein the toner bearing layer includes concavities and convexities adjacent to each other having gaps therebetween of from 1 to 3 μm.

2. The developing roller of claim 1 , wherein the toner bearing layer comprises a polymer formed of a polyisocyanate prepolymer and an alternating copolymer of fluoroethylene and vinyl ether.

3. The developing roller of claim 1 , wherein the surface of the toner bearing layer has a roughness skewness Rsk in the longitudinal direction of from −0.6 to −0.3.

4. The developing roller of claim 1 , wherein the particles having an average particle diameter of from 11 nm to 40 nm are hydrophobized silica, titanium oxide or aluminum oxide.

5. A toner used for the developing roller according claim 1 , the toner comprising:
a core particle comprising a binder resin, a colorant and a release agent; and
a fine resin particle adhering to the surface of the core particle,
wherein an amount of the release agent abstracted from 1.0 g of the toner with n-hexane is from 10 mg to 26 mg.

6. An image forming apparatus, comprising:
a latent image bearer to bear a latent image;
a charger to uniformly charge the surface of the latent image bearer;
an irradiator to irradiate the surface of the latent image bearer according to image data to form an electrostatic latent image on the surface thereof;
the developing roller according claim 1 to feed a toner to the electrostatic latent image to form a visible image on the surface of the latent image bearer;
a transferer to transfer the visible image to a transfer body; and
a fixer to fix the visible image on the transfer body.

7. The image forming apparatus of claim 6 , further comprising a cleaner comprising a cleaning blade to clean a toner adhering to the latent image bearer.

8. The image forming apparatus of claim 7 , wherein the cleaning blade comprises a strip-shaped elastic blade including a tip ridgeline contacting the surface of the latent image bearer and a surface facing the latent image bearer, and
wherein the elastic blade has a Martens hardness of from 2.0 N/mm 2 to 10.0 N/mm 2 , the Martens hardness measured by pushing a Vickers quadrangular pyramid penetrator of a hardness meter into a position on the surface facing the latent image bearer of the elastic blade by a depth of 5 μm, the position being 20 μm downstream from the tip ridgeline relative to the rotational direction of the latent image bearer.

9. The image forming apparatus of claim 7 , wherein the elastic blade has a Martens hardness of from 4.0 N/mm 2 to 6.0 N/mm 2 .

10. A developing roller, comprising:
a conductive axis body;
a conductive elastic layer overlying the conductive axis body; and
a toner bearing layer overlying the conductive elastic layer and having a surface dispersed with particles having an average particle diameter of from 11 nm to 40 nm,
wherein a rotary torque of the developing roller is proportional to a force of 2.5 N to 3.5 N detected when the developing roller is rotated at 180 rpm, and
wherein the toner bearing layer includes concavities and convexities adjacent to each other having gaps therebetween of from 1 to 3 μm.

Assignees

• Juri Keiichiro
• Matsushita Makoto
• Yasunaga Hideaki
• Ricoh Co Ltd

Inventors

• Juri Keiichiro
• Matsushita Makoto
• Yasunaga Hideaki

Classifications

• G03G9/08

  with toner particles · CPC title

• G03G21/0011

  using a blade; Details of cleaning blades, e.g. blade shape, layer forming · CPC title

• G03G15/0818 Primary

  characterised by the structure of the donor member, e.g. surface properties · CPC title