Grounded intermediate transfer members

• US 10,423,096 B2
• Filed: 07/24/2015
• Issued: 09/24/2019
• Est. Priority Date: 07/24/2015
• Status: Active Grant

• Current Assignee: HP Indigo B.V. (HP Inc.)
• Original Assignee: HP Indigo B.V. (HP Inc.)
• Inventors: Verner, Maty, Schlumm, Doron, Tagansky, Boaz
• Primary Examiner(s): Giampaolo, II, Thomas S
• Application Number:
  US15/569,340
• Publication Number:
  US 20180067422A1
• Time in Patent Office: 1,523 Days
• CPC Class Codes: G03G 15/10 using a liquid developer
• CPC Class Codes: G03G 15/161 with means for handling the intermediate support, e.g. heating, cleaning, coating with a transfer agent
• CPC Class Codes: G03G 15/1675 with means for controlling the bias applied in the transfer nip
• CPC Class Codes: G03G 15/1685 Structure, details of the transfer member, e.g. chemical composition
• CPC Class Codes: G03G 2215/1614 Transfer roll
• CPC Class Codes: G03G 2215/1619 Transfer drum

Abstract

A printing apparatus is described comprising a photoconductor for receiving an electrostatic charge pattern corresponding to an image, and one or more developers for applying a colorant to the photoconductor representative of the image. The apparatus further comprises a transfer member for transferring the image from the photoconductor onto a substrate, wherein the transfer member has a substantially grounded potential.

Claims

1. A printing apparatus comprising:

a photo imaging plate having a grounded potential;

a photoconductor attached to the photo imaging plate, the photoconductor to receive an electrostatic charge pattern corresponding to an image;

one or more developers to apply a colorant to the photoconductor representative of the image;

a transfer member to transfer the image from the photoconductor onto a substrate, wherein the transfer member has a grounded potential; and

a transfer blanket wrapped around an outer surface of the transfer member.

2. The printing apparatus of claim 1, wherein the electrostatic charge pattern is formed on the photoconductor by selectively discharging portions of a surface of the photoconductor, wherein the discharged portions of the photoconductor have a potential of between −

500V and −

800V, and the remaining portions have a potential of at least −

1300V.

3. The printing apparatus of claim 1, wherein the one or more developers are arranged for electrostatically attracting colorant to discharged portions of the photoconductor to modify a potential of the discharged portions, such that the discharged portions have a potential of between −

1000V and −

1100V.

4. The printing apparatus of claim 1, wherein the photoconductor has a negative potential with respect to the transfer member.

5. The printing apparatus of claim 1, wherein the photoconductor has a potential of at least −

400V.

6. The printing apparatus of claim 1, further comprising an impression member arranged such that the impression member has a grounded potential.

7. The printing apparatus of claim 1, comprising a charging unit to establish a substantially uniform electrostatic charge on a portion of a surface of the photoconductor.

8. The printing apparatus of claim 1, wherein the transfer member is used to contact the photoconductor.

9. The printing apparatus of claim 1, wherein the transfer member is a roller.

10. The printing apparatus of claim 1, wherein the substrate comprises a conductive substrate.

11. A method of printing onto a substrate, comprising:

forming an electrostatic charge pattern corresponding to an image on a photoconductor attached to a photo imaging plate having a grounded potential;

developing the image on the photoconductor using one or more colorants;

transferring the image from the photoconductor onto a transfer blanket wrapped around an outer surface of a grounded transfer member; and

transferring the image from the transfer blanket to a substrate.

12. The method of claim 11, further comprising charging the photoconductor to a potential of at least −

1500V prior to forming the electrostatic charge pattern.

13. The method of claim 11, wherein forming the electrostatic charge pattern comprises selectively discharging one or more portions of a surface of the photoconductor, such that the discharged portions of the photoconductor have a potential of between −

500V and −

800V, and the remaining portions have a potential of at least −

1300V.

14. The method of claim 11, wherein developing the image comprises moving the photoconductor with respect to one or more developers, such that a surface of discharged portions of the photoconductor is modified to a potential of between −

1000V and −

1100V.

15. The method of claim 11, comprising charging the photoconductor with a potential of at least −

600V to establish a substantially uniform electrostatic charge on a portion of a surface of the photoconductor.

16. The method of claim 11, wherein transferring the image from the transfer blanket to the substrate comprises contacting the substrate between the transfer blanket and an impression member with a grounded potential.

17. The method of claim 11, wherein the substrate comprises a conductive substrate.