Grounded intermediate transfer members

• US 10,642,197 B2
• Filed: 08/29/2019
• Issued: 05/05/2020
• 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:
  US16/555,414
• Publication Number:
  US 20190384209A1
• Time in Patent Office: 250 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;

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

a developer to apply a colorant to the photoconductor corresponding to the image;

an intermediate transfer member to transfer the image from the photoconductor onto a substrate, the intermediate transfer member having a grounded potential; and

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

2. The printing apparatus of claim 1, further comprising:

an impression roller to bring the substrate into contact with the intermediate transfer member.

3. The printing apparatus of claim 2, wherein the impression roller has a grounded potential.

4. The printing apparatus of claim 1, wherein the photoconductor comprises a photo receptor sheet.

5. The printing apparatus of claim 1, further comprising:

a charge roller to apply a negative potential of at least −

400V to the photoconductor.

6. The printing apparatus of claim 5, further comprising:

a digitized discharge unit to selectively discharge portions of the photoconductor to provide the electrostatic charge pattern corresponding to the image.

7. The printing apparatus of claim 1, wherein the developer comprises a binary ink developer.

8. The printing apparatus of claim 1, wherein the transfer blanket receives the image from the photoconductor and transfers the image to the substrate.

9. The printing apparatus of claim 1, further comprising:

a charging unit to perform a pre-transfer erase on the photoconductor to remove any additional charge on the photoconductor such that the potential of the photoconductor matches the potential of the photo imaging plate.

10. The printing apparatus of claim 9, wherein the charging unit comprises a light emitter.

11. The printing apparatus of claim 1, wherein the photo imaging plate has a grounded potential.

12. The printing apparatus of claim 1, wherein the transfer blanket has a grounded potential.

13. The printing apparatus of claim 1, wherein the colorant comprises a toner.

14. 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 representative of an image;

a developer to apply a colorant to the photoconductor representative of the image; and

an intermediate transfer member to transfer the image from the photoconductor onto a substrate, the intermediate transfer member having a grounded potential.

15. The printing apparatus of claim 14, further comprising:

a charge roller to apply a negative potential of at least −

1100V to the photoconductor.

16. The printing apparatus of claim 14, further comprising:

a charging unit to provide the photoconductor with a uniform electrostatic charge prior to transferring the image to the intermediate transfer member.

17. The printing apparatus of claim 14, further comprising:

a digitized discharge unit to selectively discharge portions of the photoconductor to form the electrostatic charge pattern representative of the image.

18. The printing apparatus of claim 17, wherein the digitized discharge unit comprises a laser writing head.

19. The printing apparatus of claim 14, further comprising:

a transfer blanket wrapped around an outer surface of the intermediate transfer member, the transfer blanket having a grounded potential.

20. A method of printing onto a substrate, the method comprising:

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

developing the image on the photoconductor using a colorant;

transferring the image from the photoconductor onto a grounded intermediate transfer member; and

transferring the image from the intermediate transfer member to a substrate.