Electrophotographic photoreceptor and image forming apparatus using the photoreceptor

• US 20030215726A1
• Filed: 03/11/2003
• Published: 11/20/2003
• Est. Priority Date: 03/11/2002
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Kawasaki, Yoshiaki, Sugino, Akihiro, Kurimoto, Eiji, Ikegami, Takaaki, Kitajima, Ryohichi
• Granted Patent: US 6,853,823 B2
• Time in Patent Office: Days
• US Class Current: 430/58.05
• CPC Class Codes: G03G 5/047 characterised by the charge-generation layers or charge transport layers G03G5/0433 and G03G5/0436 take precedence
• CPC Class Codes: G03G 5/0507 Inorganic compounds
• CPC Class Codes: Y10S 430/103 Radiation sensitive composition or product containing specified antioxidant

Abstract

An electrophotographic photoreceptor includes an electroconductive substrate. A charge generation layer overlies the electroconductive substrate. A first charge transport layer overlying the charge generation layer includes a first charge transport material (D1) and a first binder resin (R1). A second charge transport layer overlying the first charge transport layer includes a filler, a second charge transport material (D2) and a second binder resin (R2). The first and second charge transport layers have a total thickness of from 5 to 25 μm. A weight ratio (D1/R1) of the first charge transport material (D1) to the first binder resin (R1) in the first charge transport layer is greater than a weight ratio (D2/R2) of the second charge transport material (D2) to the second binder resin (R2) in the second charge transport layer.

Claims

1. An electrophotographic photoreceptor comprising:

an electroconductive substrate;

a charge generation layer overlying the electroconductive substrate;

a first charge transport layer overlying the charge generation layer, comprising a first charge transport material and a first binder resin; and

a second charge transport layer overlying the first charge transport layer, comprising a filler, a second charge transport material and a second binder resin,

wherein the first and second charge transport layers have a total thickness of from about 5 to about 25 μ

m, and wherein a weight ratio of the first charge transport material to the first binder resin is greater than a weight ratio of the second charge transport material to the second binder resin.

2. The electrophotographic photoreceptor of claim 1, wherein a thickness of the first charge transport layer is not less than a thickness of the second charge transport layer.

3. The electrophotographic photoreceptor of claim 1, wherein the filler comprises an inorganic material.

4. The electrophotographic photoreceptor of claim 3, wherein the inorganic material comprises at least one of silica, alumina, and titanium oxide.

5. An image forming apparatus comprising:

the electrophotographic photoreceptor according to claim 1;

a charger configured to charge the electrophotographic photoreceptor;

an irradiator configured to irradiate the electrophotographic photoreceptor to form an electrostatic latent image thereon;

an image developer configured to develop the electrostatic latent image with a developer comprising a toner adapted to form a toner image on the electrophotographic photoreceptor; and

a transferer configured to transfer the toner image onto at least one of an intermediate transferer and a transfer sheet,

wherein a non-irradiated part of the photoreceptor has a potential of from about −

300 to about −

800 V.

6. The image forming apparatus of claim 5, wherein the irradiator comprises at least one of a laser diode and a light emitting diode, and the electrostatic latent image has an image resolution not less than 1,200 dpi.

7. The image forming apparatus of claim 5, further comprising:

an intermediate transferer, wherein the toner image developed on the electrophotographic photoreceptor is transferred onto the intermediate transferer and transferred onto the transfer sheet therefrom.

8. The image forming apparatus of claim 7, wherein the intermediate transferer comprises an elastic seamless belt including an elastic material.

9. A tandem full color image forming apparatus comprising:

a plurality of electrophotographic photoreceptors, each of the electrophotographic photoreceptors according to claim 1;

a plurality of chargers configured to charge the electrophotographic photoreceptors;

a plurality of irradiators configured to irradiate the electrophotographic photoreceptors to form electrostatic latent images thereon;

a plurality of image developers configured to develop the electrostatic latent images with developers each comprising a color toner adapted to form color toner images on the electrophotographic photoreceptors; and

a plurality of transferers configured to transfer the color toner images onto at least one of an intermediate transferer and a transfer sheet.

10. The tandem full color image forming apparatus of claim 9, further comprising:

an intermediate transferer, wherein each of the toner images developed on each of the electrophotographic photoreceptors is transferred onto the intermediate transferer so as to be overlaid thereon and the overlaid toner images are transferred onto the transfer sheet therefrom.

11. The tandem full color image forming apparatus of claim 9, wherein the intermediate transferee comprises an elastic seamless belt including an elastic material.

12. A process cartridge comprising:

the electrophotographic photoreceptor according to claim 1;

and

at least one of

(a) a charger configured to charge the electrophotographic photoreceptor;

(b) an irradiator configured to irradiate the electrophotographic photoreceptor to form an electrostatic latent image thereon, wherein a non-irradiated part of the photoreceptor has a potential of from about −

300 to about −

800 V;

(c) an image developer configured to develop the electrostatic latent image with a developer comprising a toner adapted to form a toner image on the electrophotographic photoreceptor; and

(d) a transferer configured to transfer the toner image directly or indirectly onto a transfer sheet.

13. An electrophotographic photoreceptor comprising:

an electroconductive substrate;

a charge generation layer overlying the electroconductive substrate;

a first charge transport layer overlying the charge generation layer, comprising a first charge transport means and a first binder means; and

a second charge transport layer overlying the first charge transport layer, comprising a filler, a second charge transport means and a second binder means,

wherein the first and second charge transport layers have a total thickness of from about 5 to about 25 μ

m, and wherein a weight ratio of the first charge transport means to the first binder means is greater than a weight ratio of the second charge transport means to the second binder means.