Developer carrying member, developing assembly, process cartridge, and image forming apparatus

• US 9,261,811 B2
• Filed: 11/04/2014
• Issued: 02/16/2016
• Est. Priority Date: 11/13/2013
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Hagiwara, Kazunari, Orihara, Tatsuaki, Tokiwa, Shuhei, Ito, Yoshikuni, Matsumoto, Yasuyuki, Fuei, Naoki, Fukatsu, Makoto
• Primary Examiner(s): GRAY, FRANCIS C
• Application Number:
  US14/532,402
• Publication Number:
  US 20150132031A1
• Time in Patent Office: 469 Days
• US Class Current: 1/1
• CPC Class Codes: G03G 15/0808 characterised by the developer supplying means, e.g. structure of developer supply roller
• CPC Class Codes: G03G 15/0818 characterised by the structure of the donor member, e.g. surface properties

Abstract

A developing roller that is capable of carrying toner on a surface thereof, and that supplies the toner carried on the surface to a surface of a photosensitive drum when a voltage is applied thereto, includes: a rubber layer; and a surface layer that covers the rubber layer, contains alumina, and has a higher volume resistivity than the rubber layer.

Claims

1. A developer carrying member that is capable of carrying a developer on a surface thereof, and that supplies the developer carried on the surface to a surface of an image bearing member when a voltage is applied thereto, comprising:

an elastic layer; and

a surface layer that covers the elastic layer, contains alumina, and has a higher volume resistivity than the elastic layer,

wherein an Asker-C hardness is no lower than 45 degrees and no higher than 70 degrees, and

a microhardness measured using a nanoindentation method is no lower than 50 MPa and no higher than 220 MPa.

2. The developer carrying member according to claim 1, wherein a volume resistance is greater than 2×

10⁴Ω and

smaller than 5×

10⁶Ω

.

3. The developer carrying member according to claim 1, wherein a thickness of the surface layer is no smaller than 0.01 μ

m and no larger than 5.0 μ

m, and

the volume resistivity of the surface layer is no smaller than 10¹⁰ Ω

cm and no larger than 10¹⁴ Ω

cm.

4. The developer carrying member according to claim 1, wherein a thickness of the surface layer is no smaller than 0.1 μ

m and no larger than 2.5 μ

m, and

the volume resistivity of the surface layer is no smaller than 5×

10¹⁰ Ω

cm and no larger than 5×

10¹³ Ω

cm.

5. The developer carrying member according to claim 1, wherein an average diameter of a pore distribution of the surface layer is no smaller than 0.1 nm and no larger than 500 nm.

6. The developer carrying member according to claim 1, wherein the surface layer is formed using a colloidal alumina solution.

7. The developer carrying member according to claim 1, wherein the surface layer is formed by subjecting aluminum alkoxide to a hydrolysis process and a condensation process.

8. A developing assembly comprising:

a developer container housing a developer; and

the developer carrying member according to claim 1.

9. A process cartridge that can be attached to a main body of an image forming apparatus detachably in order to perform an image formation process, comprising:

an image bearing member capable of bearing a developer image; and

the developer carrying member according to claim 1, which forms the developer image by developing an electrostatic latent image on the image bearing member.

10. An image forming apparatus comprising:

an image bearing member capable of bearing a developer image;

the developer carrying member according to claim 1, which forms the developer image by developing an electrostatic latent image on the image bearing member; and

applying means for applying a voltage to the developer carrying member.