Titanylphthalocyanine crystal and method of producing the titanylphthalocyanine crystal, and electrophotographic photoreceptor, method, apparatus and process cartridge using the titanylphthalocyanine crystal

• US 20040033428A1
• Filed: 06/05/2003
• Published: 02/19/2004
• Est. Priority Date: 06/13/2002
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Niimi, Tatsuya
• Granted Patent: US 7,419,751 B2
• Time in Patent Office: Days
• US Class Current: 430/59.5
• CPC Class Codes: C09B 67/0016 of phthalocyanines
• CPC Class Codes: C09B 67/0026 of phthalocyanine pigments
• CPC Class Codes: G03G 5/0696 Phthalocyanines

Abstract

A titanylphthalocyanine crystal having an X-ray diffraction spectrum having plural diffraction peaks and a primary particle diameter not greater than 0.2 μm, wherein a maximum diffraction peak is observed at a Bragg (2θ) angle of 27.2±0.2°; main peaks are observed at 9.4°, 9.6° and 24.0°; and a minimum diffraction peak is observed at 7.3°; and preferably no diffraction peak is observed at an angle greater than 7.3° and less than 9.4° when a specific X-ray of CuKα having a wavelength of 1.542 Å irradiates the titanylphthalocyanine crystal.

Claims

1. A titanylphthalocyanine crystal having a CuKα

1.542 Å

X-ray diffraction spectrum comprising plural diffraction peaks and a primary particle diameter not greater than 0.2 μ

m, wherein a maximum diffraction peak is observed at a Bragg (2θ

) angle of 27.2°

;

main peaks are observed at 9.4°

, 9.6° and

24.0°

; and

a minimum diffraction peak is observed at 7.3°

; and

no diffraction peak is observed at an angle greater than 7.3° and

less than 9.4°

, wherein said angles may vary by ±

0.2° and

the minimum interval where no peak is observed between required peaks at 7.3 and 9.4 is 2.0 degrees absolute or more.

2. The titanylphthalocyanine crystal of claim 1, wherein no diffraction peak is observed at 26.3°

.

5. An electrophotographic photoreceptor comprising:

an electroconductive substrate;

a charge generation layer located overlying the electroconductive substrate and comprising the titanylphthalocyanine crystal according to claim 1;

and

a charge transport layer located overlying the charge generation layer.

6. The electrophotographic photoreceptor of claim 5, wherein the charge transport layer comprises a charge transport polymer material.

7. The electrophotographic photoreceptor of claim 5, further comprising a protection layer located overlying the charge transport layer.

8. The electrophotographic photoreceptor of claim 6, wherein the protection layer comprises at least one of an inorganic pigment and a metal oxide, which have a resistivity not less than 10₁₀ Ω

·

cm.

9. The electrophotographic photoreceptor of claim 8, comprising a metal oxide selected from the group consisting of alumina, titanium oxide and silica.

10. The electrophotographic photoreceptor of claim 8, comprising α

-alumina.

11. The electrophotographic photoreceptor of claim 7, wherein the protection layer comprises a charge transport polymer material.

12. The electrophotographic photoreceptor of claim 5, wherein an oxide film is formed on the substrate by anodizing.

13. An image forming method comprising:

charging the electrophotographic photoreceptor according to claim 5;

irradiating the electrophotographic photoreceptor with imagewise light to form an electrostatic latent image thereon;

developing the electrostatic latent image with a developer comprising a toner to form a toner image thereon; and

transferring the toner image onto a transfer sheet.

14. An image forming apparatus comprising:

at least one image forming unit comprising;

the electrophotographic photoreceptor according to claim 5;

a charger configured to charge the electrophotographic photoreceptor;

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

an image developer configured to develop the electrostatic latent image with a developer comprising a toner to form a toner image thereon; and

a transferer configured to transfer the toner image onto a transfer sheet.

15. The image forming apparatus of claim 14, comprising plural image forming units.

16. The image forming apparatus of claim 14, wherein the charger is contacted or located close to the electrophotographic photoreceptor.

17. The image forming apparatus of claim 16, wherein the charger is located close to the electrophotographic photoreceptor and a gap between the charger and the electrophotographic photoreceptor is not greater than 200 μ

m.

18. The image forming apparatus of claim 14, wherein the charger applies a DC voltage overlapped with an AC voltage to the electrophotographic photoreceptor.

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

the electrophotographic photoreceptor according to claim 5;

and at least one of;

a charger configured to charge the electrophotographic photoreceptor;

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

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

a transferer configured to transfer the toner image onto a transfer sheet;

a cleaner configured to clean the photoreceptor after the toner image is transferred into the transfer sheet; and

a discharger configured to discharge charges remaining on the photoreceptor after the toner image is transferred into the transfer sheet.

3. A method of producing a titanylphthalocyanine crystal comprising:

subjecting a titanylphthalocyanine, which is either amorphous or low-crystalline, and which has a maximum CuKα

1.542 Å

diffraction peak having a half width not less than 1°

at a Bragg (2θ

) angle of from 7.0 to 7.5°

±

0.2° and

an average primary particle diameter not greater than 0.1 μ

m, to crystal conversion with an organic solvent in the presence of water; and

separating the titanylphthalocyanine from the organic solvent before the titanylphthalocyanine crystal grows to a size where the average primary particle diameter is greater than 0.2 μ

m.

4. The method of producing a titanylphthalocyanine crystal of claim 3, wherein the organic solvent is selected from the group consisting of tetrahydrofuran, toluene, dichloromethane, carbon bisulfide, o-dichlorobenzene and 1,1,2-trichloroethane.