Imaging member

• US 20060286471A1
• Filed: 06/21/2005
• Published: 12/21/2006
• Est. Priority Date: 06/21/2005
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Junginger, Johann, Liebermann, George, Evans, Kent, Mishra, Satchidanand, Carmichael, Kathleen M., Post, Richard L., Zak, Michael, Horgan, Anthony M., Domm, Edward, Prosser, Dennis J.
• Granted Patent: US 7,666,560 B2
• Time in Patent Office: Days
• US Class Current: 430/58.800
• CPC Class Codes: G03G 5/043 Photoconductive layers characterised by having two or more layers or characterised by their composite structure
• 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 5/0525 Coating methods
• CPC Class Codes: G03G 5/0564 Polycarbonates
• CPC Class Codes: G03G 5/061443 benzidine

Abstract

An imaging member includes a charge generating layer and a charge transport layer. The charge transport layer includes a first surface in contact with the charge generating layer and a second surface. The charge transport layer includes a film forming polymer binder and a charge transport component dispersed therein. The concentration of the charge transport component in the charge transport layer is at a peak in a region of the charge transport intermediate the first and second surfaces of the charge transport layer.

Claims

1. an imaging member comprising:

a charge generating layer; and

a charge transport layer comprising a first surface in contact with the charge generating layer and a second surface, the charge transport layer comprising a film forming polymer binder and a charge transport component dispersed therein, wherein the concentration of the charge transport component in the charge transport layer is at a peak in a region of the charge transport intermediate the first and second surfaces of the charge transport layer.

2. The imaging member of claim 1, wherein the concentration of the charge transport component in a first region of the charge transport layer adjacent the first surface is from about 5% to about 95% of the peak concentration of the charge transport component.

3. The imaging member of claim 2, wherein the concentration of the charge transport component in the first region Is from about 10% to about 80% of the peak concentration of the charge transport component.

4. The imaging member of claim 1, wherein the concentration of the charge transport component in the charge transport layer is lower in a second region of the charge transport layer adjacent the second surface of the charge transport layer than the peak concentration of the charge transport component.

5. The imaging member of claim 4, wherein the second region of the charge transport layer is spaced from the first region by a region in which the peak concentration of the charge component is located.

6. The imaging member of claim 4, wherein the concentration of the charge transport component in the second region is from about 5% to about 95% of the concentration of the peak charge transport component.

7. The imaging member of claim 6, wherein the concentration of the charge transport component in the second region is from about 10% to about 80% of the peak concentration of the charge transport component.

8. The imaging member of claim 1, wherein the charge transport layer further comprises a stabilizing hindered phenol and wherein the concentration of the hindered phenol increases in inverse relation to the concentration of the charge transport component towards a surface of the charge transport layer furthest from the charge generation layer.

9. The imaging member of claim 1, wherein the charge transport component progressively increases in concentration from the first surface and decreases from the peak to the second surface of the charge transport layer.

10. The imaging member of claim 1, wherein the charge transport layer comprises a first layer in which the concentration of the charge transport component is from about 5 to about 35 weight percent, based on the total weight of the first layer and a second layer in which the concentration of the charge transport component is from about 35 to about 90 weight percent, based on the total weight of the second layer.

11. The imaging member of claim 1, wherein the charge transport layer comprises a first layer and a second layer, the first layer being of a lower thickness than the second layer.

12. The imaging member of claim 11, wherein the second layer comprises the peak concentration of the charge transport component.

13. The imaging member of claim 11, wherein the first layer is from about 5 microns to about 15 microns in thickness and the second layer is from about 10 microns to about 35 microns in thickness.

14. The imaging member of claim 1, wherein the charge transport component is molecularly dispersed in the film forming polymer to form a solid solution.

15. The imaging member of claim 1, wherein the charge transport component comprises an aryl amine selected from the group consisting of diphenyl diamines, triphenyl amines, terphenyl diamines, and combinations thereof.

16. The imaging member of claim 15, wherein the charge transport component comprises (N,N′

-diphenyl-N,N′

-bis[3-methylphenyl]-[1,1′

-biphenyl]-4,4′

-diamine).

17. The imaging member of claim 1, wherein the charge transport component is the same throughout the charge transport layer.

18. The imaging member of claim 1, wherein the charge generating layer comprises a photogenerating material and the charge transport layer is substantially free of photogenerating materials.

19. A xerographic printing system comprising the imaging member of claim 1.

20. An imaging member comprising;

an optional substrate;

a source of charge; and

a charge transport layer which receives charge from the source, the charge transport layer comprising a film forming polymer binder and a charge transport component dispersed therein, the charge transport layer comprising a first region and a second region, the second region being spaced from the source of charge by the first region, the first region having a lower charge mobility than the second region whereby charge deficient spots are reduced as compared with an imaging member formed without the first region.

21. The imaging member of claim 20, further comprising a third region spaced from the first region by the second region, the third region having a lower charge mobility than the second region.

22. The imaging member of claim 20, wherein the first region comprises a lower concentration of charge transport component than the second region.

23. A method comprising:

forming a charge transport layer on a charge generating layer comprising;

depositing a first layer on the charge generating layer, the first layer comprising a film forming polymer binder and optionally a charge transport component dispersed therein;

depositing at least one second layer directly or indirectly on the first layer such that the at least one second layer is spaced from the charge generating layer by the first layer, the at least one second layer comprising a film forming polymer binder and a charge transport component dispersed therein, a concentration of charge transport component in the at least one second layer, upon drying, being higher than a concentration of charge transport component in the first layer;

optionally depositing a third layer on the at least one second layer, the third layer comprising a film forming polymer binder and optionally a charge transport component dispersed therein, a concentration of charge transport component in the third layer, upon drying, being lower than a concentration of charge transport component in an adjacent second layer; and

optionally depositing an overcoat layer over the charge transport layer.

24. The method of claim 23, wherein the first layer further includes a solvent and wherein the method comprises depositing at least one second layer prior to complete drying of the first layer.

25. The method of claim 24, wherein the first layer, when deposited, is substantially free of charge transport components and wherein the transport component diffuses from the second layer into the first layer prior to complete drying of the first layer.