Electrophotographic photoreceptor, method of manufacturing the photoreceptor, and electrophotographic image forming method and apparatus using the photoreceptor

• US 6,521,387 B2
• Filed: 05/09/2001
• Issued: 02/18/2003
• Est. Priority Date: 05/09/2000
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Kawasaki, Yoshiaki
• Primary Examiner(s): Chapman, Mark A.
• Application Number:
  US09/851,128
• Publication Number:
  US 20020094487A1
• Time in Patent Office: 650 Days
• Field of Search: 430/59.5, 430/58.05, 399/159
• US Class Current: 430/59.5
• 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: G03G 5/0521 comprising one or more heterocyclic groups
• CPC Class Codes: G03G 5/0696 Phthalocyanines

Abstract

A photoreceptor including an electroconductive substrate; a charge generation layer formed overlying the electroconductive substrate and including as a charge generation material a titanyl phthalocyanine crystal having an X-ray diffraction spectrum such that a maximum diffraction peak is observed at a Bragg (2θ) angle of 27.2°±0.2° when a specific X-ray of Cu-Kα having wavelength of 1.542 Å irradiates the titanyl phthalocyanine crystal; and a charge transport layer formed on the charge generation layer and including a binder resin, a charge transport material, water and tetrahydrofuran, wherein a weight ratio of the water to the tetrahydrofuran in the charge transport layer is from 1/50 to 1/0.5.

Claims

1. A photoreceptor comprising:

an electroconductive substrate;

a charge generation layer overlying the electroconductive substrate and comprising as a charge generation material a titanyl phthalocyanine crystal having an X-ray diffraction spectrum such that a maximum diffraction peak is observed at a Bragg (2θ

) angle of 27.2°

±

0.2°

when a specific X-ray of Cu-Kα

having a wavelength of 1.542 Å

irradiates the titanyl phthalocyanine crystal; and

a charge transport layer on the charge generation layer and comprising a binder resin, a charge transport material, water and tetrahydrofuran,

wherein a weight ratio of the water to the tetrahydrofuran in the charge transport layer is from 1/50 to 1/0.5.

2. The photoreceptor according to claim 1, wherein the tetrahydrofuran is present in the charge transport layer in an amount of from 0.01 to 0.5% by weight based on total solid components in the charge transport layer.

3. The photoreceptor according to claim 1, wherein the binder resin in the charge transport layer comprises a bisphenol-Z-form polycarbonate resin.

4. The photoreceptor according to claim 1, wherein the binder resin in the charge transport layer has a water absorption not greater than 0.30%.

5. The photoreceptor according to claim 1, further comprising an undercoat layer between the electroconductive substrate and the charge generation layer.

6. A method for manufacturing a photoreceptor comprising:

forming a charge generation layer overlying an electroconductive substrate, wherein the charge generation layer comprises a titanyl phthalocyanine crystal having an X-ray diffraction spectrum such that a maximum diffraction peak is observed at a Bragg (2θ

) angle of 27.2°

±

0.2°

when a specific X-ray of Cu-Kα

having a wavelength of 1.542 Å

irradiates the titanyl phthalocyanine crystal; and

forming a charge transport layer on the charge generation layer by coating the charge generation layer with a charge transport layer coating liquid comprising a charge transport material, a binder resin, tetrahydrofuran and water,

wherein a weight ratio of the water to the tetrahydrofuran in the charge transport layer is from 1/50 to 1/0.5.

7. The method according to claim 6, wherein the tetrahydrofuran is present in the charge transport layer coating liquid in an amount of from 0.1 to 4.0% by weight.

8. The method according to claim 6, wherein the binder resin in the charge transport layer comprises a bisphenol-Z-form polycarbonate resin.

9. An image forming method comprising:

charging a photoreceptor;

irradiating the photoreceptor with light to form an electrostatic latent image on the photoreceptor;

developing the electrostatic latent image with a developer comprising a toner to form toner image on the photoreceptor;

transferring the toner image on a receiving material;

cleaning a surface of the photoreceptor; and

discharging a remaining charge on the photoreceptor, wherein the photoreceptor comprises;

an electroconductive substrate;

a charge generation layer overlying the electroconductive substrate and comprising as a charge generation material a titanyl phthalocyanine crystal having an X-ray diffraction spectrum such that a maximum diffraction peak is observed at a Bragg (2θ

) angle of 27.2°

±

0.2°

when a specific X-ray of Cu-Kα

having a wavelength of 1.542 Å

irradiates the titanyl phthalocyanine crystal; and

a charge transport layer on the charge generation layer and comprising a binder resin, a charge transport material, water and tetrahydrofuran;

wherein a weight ratio of the water to the tetrahydrofuran in the charge transport layer is from 1/50 to 1/0.5.

10. The image forming method according to claim 9, wherein the tetrahydrofuran is present in the charge transport layer in an amount of from 0.01 to 0.5% by weight based on total solid components in the charge transport layer.

11. The image forming method according to claim 9, wherein the binder resin in the charge transport layer comprises a bisphenol-Z-form polycarbonate resin.

12. The image forming method according to claim 9, wherein the binder resin in the charge transport layer has a water absorption not greater than 0.30%.

13. The image forming method according to claim 9, further comprising an undercoat layer between the electroconductive substrate and the charge generation layer.

14. an image forming apparatus comprising:

a photoreceptor;

a charger configured to charge the photoreceptor;

a light irradiator configured to irradiate the photoreceptor with light to form an electrostatic latent image on the photoreceptor;

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

an image transfer configured to transfer the toner image on a receiving material;

a cleaner configured to clean the surface of the photoreceptor; and

a discharger configured to discharge a remaining charge on the photoreceptor;

wherein the photoreceptor comprises;

an electroconductive substrate;

a charge generation layer overlying the electroconductive substrate and comprising as a charge generation a titanyl phthalocyanine crystal having an X-ray diffraction spectrum such that a maximum diffraction peak is observed at a Bragg (2θ

) angle of 27.2°

±

0.2°

when a specific X-ray of Cu-Kα

having a wavelength of 1.542 Å

irradiates the titanyl phthalocyanine crystal; and

a charge transport layer on the charge generation layer and comprising a binder resin a charge transport material, water and tetrahydrofuran;

wherein a weight ratio of the water to the tetrahydrofuran in the charge transport layer is from 1/50 to 1/0.5.

15. The image forming apparatus according to claim 14, wherein the tetrahydrofuran is present in the charge transport layer in an amount of from 0.01 to 0.5% by weight based on total solid components in the charge transport layer.

16. The image forming apparatus according to claim 14, wherein the binder resin in the charge transport layer comprises a bisphenol-Z-form polycarbonate resin.

17. The image forming apparatus according to claim 14, wherein the binder resin in the charge transport layer has a water absorption not greater than 0.30%.

18. The image forming apparatus according to claim 14, further comprising an undercoat layer between the electroconductive substrate and the charge generation layer.

19. A process cartridge for an electrophotographic image forming apparatus, comprising:

a housing; and

a photoreceptor,

wherein the photoreceptor comprises;

a charge generation layer overlying the electroconductive substrate and comprising as a charge generation material a titanyl phthalocyanine crystal having an X-ray diffraction spectrum such that a maximum diffraction peak is observed at a Bragg (2θ

) angle of 27.2°

±

0.2°

when a specific X-ray of Cu-Kα

having a wavelength of 1.542 Å

irradiates the titanyl phthalocyanine crystal; and

a charge transport layer on the charge generation layer and comprising a binder resin, a charge transport material, water and tetrahydrofuran;

wherein a weight ratio of the water to the tetrahydrofuran in the charge transport layer is from 1/50 to 1/0.5.

20. The process cartridge according to claim 19, wherein the tetrahydrofuran is present in the charge transport layer in an amount of from 0.01 to 0.5% by weight based on total solid components in the charge transport layer.

21. The process cartridge according to claim 19, wherein the binder resin in the charge transport layer comprises a bisphenol-Z-form polycarbonate resin.

22. The process cartridge according to claim 19, wherein the binder resin in the charge transport layer has a water absorption not greater than 0.30%.

23. The process cartridge according to claim 19, further comprising an undercoat layer between the electroconductive substrate and the charge generation layer.