Process cartridge and image forming apparatus

Patent metadata

Field	Value
Publication number	US-11003106-B2
Application number	US-201916679524-A
Country	US
Kind code	B2
Filing date	Nov 11, 2019
Priority date	Nov 14, 2018
Publication date	May 11, 2021
Grant date	May 11, 2021

Abstract

A charging member 2 that charges an image bearing member 1 has an electrically conductive support and an elastic layer in contact with the image bearing member 1 . The elastic layer includes a semi-conductive rubber composition having a matrix-domain structure including a matrix and domains having electric conductivity. The matrix has a higher volume resistivity than the domain. The developer includes a toner having toner particles. The toner particles each have a surface layer including an organosilicon polymer. The organosilicon polymer has a structure represented by R—SiO 3/2 (R is a hydrocarbon group having at least 1 and not more than 6 carbon atoms). The adhesion ratio of the organosilicon polymer on the surface of the toner particle is 90% or more.

First claim

What is claimed is:

1. A process cartridge for use in an image forming apparatus, comprising:
an image bearing member configured to bear a developer image formed by developing an electrostatic latent image with a developer;
a charging member configured to contact the image bearing member and charge the image bearing member; and
a cleaning member configured to contact a surface of the image bearing member and clean the surface,
wherein
the charging member has an electrically conductive support and an elastic layer which is positioned in contact with the image bearing member;
the elastic layer includes a semi-conductive rubber or resin composition having a matrix-domain structure including a matrix and domains having electric conductivity; and
the matrix has a higher volume resistivity than the domain;
a developer including a toner having toner particles;
the toner particles each have a surface layer including an organosilicon polymer and being formed from a hydrolysate;
the organosilicon polymer has a structure represented by a following formula:
R—SiO 3/2

wherein R represents a hydrocarbon group having at least 1 and not more than 6 carbon atoms; and
wherein when a ratio of (i) an amount of silicon in the toner particles after washing with an aqueous solution of neutral detergent to (ii) the amount of silicon in the toner particles before the washing with the aqueous solution of neutral detergent is defined as an adhesion ratio, the adhesion ratio of the organosilicon polymer on the surface of each of the toner particles is 90% or more.

2. The process cartridge according to claim 1 , further comprising:
a developing member configured to supply the developer to the image bearing member.

3. The process cartridge according to claim 1 , wherein
the toner has a Martens hardness of at least 200 MPa and not more than 1100 MPa when measured under a maximum load of 2.0×10 −4 N.

4. The process cartridge according to claim 1 , wherein
the average number of carbon atoms directly bonded to a silicon atom in the organosilicon polymer is at least 1 and not more than 3 per one silicon atom.

5. The process cartridge according to claim 1 , wherein
each of the domains includes an electrically conductive particle.

6. The process cartridge according to claim 1 , wherein
a circumferential surface of the elastic layer that is in contact with the image bearing member is configured such that portions made of the domains are scattered on a surface composed of the matrix.

7. An image forming apparatus comprising:
an apparatus main body; and
a process cartridge according to claim 1 that is detachably attachable to the apparatus main body.

Assignees

• Canon Kk

Inventors

• Agata Shinichi
• Hagiwara Shinichi
• Mitsui Yoshihiro
• Ikada Kosuke
• Yamawaki Kentaro

Classifications

• G03G9/09725

  Silicon-oxides; Silicates · CPC title

• G03G15/0233 Primary

  Structure, details of the charging member, e.g. chemical composition, surface properties · CPC title

• G03G21/1842

  for guiding and mounting the process cartridge, positioning, alignment, locks (G03G21/1864 and G03G21/1871 take precedence) · CPC title

• G03G9/0821

  characterised by physical parameters (magnetic parameters G03G9/083) · CPC title

• G03G9/08773

  Polymers having silicon in the main chain, with or without sulfur, oxygen, nitrogen or carbon only · CPC title