DEVELOPER CARRYING MEMBER AND IMAGE FORMING APPARATUS

• US 20160033894A1
• Filed: 10/13/2015
• Published: 02/04/2016
• Est. Priority Date: 06/30/2014
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Tokiwa, Shuhei, Hagiwara, Kazunari, Orihara, Tatsuaki, Fukatsu, Makoto, Nakamoto, Atsushi
• Granted Patent: US 9,405,217 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G03G 15/08 using a solid developer, e.g. powder developer
• 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

Provided is a developer carrying member which depends on a sheet-passing speed to a small extent while maintaining satisfactory developability, and can stably suppress a fogging amount with time. The developer carrying member includes: an electro-conductive mandrel; and an electro-conductive elastic layer, in which: the elastic layer contains a resin j, an electro-semiconductive particle p, and an electro-conductive particle c; and when an electroconductivity of the resin j is defined as σ_j, a dielectric constant of the resin j is defined as ∈_j, an electroconductivity of the electro-semiconductive particle p is defined as σ_p and a dielectric constant of the electro-semiconductive particle p is defined as ∈_p, σ_j, ∈_j, σ_p, and ∈_p satisfy relationships represented by the following formulae (1) and (2), σ_j, ∈_j, σ_p and ∈_p being calculated by an AC impedance method.

σ_j<σ_p<0.05 S/cm  (1)

∈_p<∈_j  (2)

Claims

1. A developer carrying member, comprising:

an electro-conductive mandrel; and

an electro-conductive elastic layer,

wherein;

the elastic layer contains

a resin j,

an electro-semiconductive particle p, and

an electro-conductive particle c; and

when

an electroconductivity of the resin j is defined as σ

_j,

a dielectric constant of the resin j is defined as ∈

_j,

an electroconductivity of the electro-semiconductive particle p is defined as σ

_p, and

a dielectric constant of the electro-semiconductive particle p is defined as ∈

_p,

σ

_j, ∈

_j, σ

_p, and ∈

_p satisfy relationships represented by the following formulae (1) and (2),

σ

_j, ∈

_j, σ

_p and ∈

_p being calculated by an AC impedance method.

σ

_j<

σ

_p<

0.05 S/cm 

 

(1)

∈

_p<

∈

_j 

 

(2)

2. A developer carrying member according to claim 1, wherein in the electro-conductive elastic layer,

when

an electroconductivity of the electro-semiconductive particle p component is defined as σ

_p,

a dielectric constant of the electro-semiconductive particle p component is defined as ∈

_p,

an electroconductivity of a component u except the electro-semiconductive particle p is defined as σ

_u, and

a dielectric constant of a component u except the electro-semiconductive particle p is defined as ∈

_u,

σ

_p, ∈

_p, σ

_u, and ∈

_u have a relationship represented by the following formula (10),

|log₁₀[(σ

_p/∈

_p)/(σ

_u/∈

_u)]|<

1.5 

 

(10)

Wherein

σ

_p, ∈

_p, σ

_u, and ∈

_u being calculated through separation of constituent components of the layer into the electro-semiconductive particle p component and the component u except the electro-semiconductive particle p by the AC impedance method.

3. A developer carrying member according to claim 1, wherein the resin j, the electro-semiconductive particle p, and the electro-conductive particle c incorporated into the electro-conductive elastic layer are a urethane resin, a zinc oxide particle, and a carbon particle, respectively.

4. A developer carrying member according to claim 3, wherein a volume occupancy of the zinc oxide particle in the electro-conductive elastic layer increases toward a vicinity of a surface of the electro-conductive elastic layer.

5. An image forming apparatus, comprising:

an image-bearing member configured to bear an electrostatic latent image; and

a developer carrying member configured to carry a developer and to contact with the image-bearing member to develop the electrostatic latent image with the developer,

wherein;

the developer carrying member comprise;

an electro-conductive mandrel; and

an electro-conductive elastic layer,

wherein;

the elastic layer contains

a resin j,

an electro-semiconductive particle p, and

an electro-conductive particle c; and

when

an electroconductivity of the resin j is defined as σ

_j,

a dielectric constant of the resin j is defined as ∈

_j,

an electroconductivity of the electro-semiconductive particle p is defined as σ

_p, and

a dielectric constant of the electro-semiconductive particle p is defined as ∈

_p,

σ

_j, ∈

_j, σ

_p, and ∈

_p satisfy relationships represented by the following formulae (1) and (2),

σ

_j, ∈

_j, σ

_p and ∈

_p being calculated by an AC impedance method.

σ

_j<

σ

_p<

0.05 S/cm 

 

(1)

∈

_p<

∈

_j 

 

(2)