CHARGING ELEMENTS IN ELECTROPHOTOGRAPHIC PRINTERS

• US 20180217519A1
• Filed: 01/14/2016
• Published: 08/02/2018
• Est. Priority Date: 01/14/2016
• Status: Active Grant

• Current Assignee: HP Indigo B.V. (HP Inc.)
• Original Assignee: HP Indigo B.V. (HP Inc.)
• Inventors: ANUFA, Asaf, BORENSTAIN, Shmuel, VERNER, Maty
• Granted Patent: US 10,331,056 B2
• Time in Patent Office: Days
• CPC Class Codes: G03G 15/0266 Arrangements for controlling the amount of charge
• CPC Class Codes: G03G 15/10 using a liquid developer
• CPC Class Codes: G03G 15/104 Preparing, mixing, transporting or dispensing developer
• CPC Class Codes: G03G 15/169 with means for preconditioning the toner image before the transfer G03G15/095 and G03G15/11 take precedence
• CPC Class Codes: G03G 21/06 Eliminating residual charges from a reusable imaging member

Abstract

In certain examples, a liquid electrophotographic printer has a charge erasing element and a charging element. The charge erasing element at least partially discharges a charged photo imaging plate and a charged layer of liquid toner and the charging element at least partially recharges the layer of liquid toner and the photo imaging plate.

Claims

1. A liquid electrophotographic printer comprising:

a photo imaging plate;

a first charging element to charge the photo imaging plate;

at least one image development unit to develop a latent image by depositing a charged layer of liquid toner onto the charged photo imaging plate;

a charge erasing element to at least partially discharge the charged photo imaging plate and the charged layer of liquid toner; and

a second charging element to at least partially recharge the layer of liquid toner and the photo imaging plate.

2. The liquid electrophotographic printer of claim 1 comprising an intermediate transfer member, wherein the intermediate transfer member is grounded, and

wherein the grounded intermediate transfer member receives the at least partially recharged layer of liquid toner from the at least partially recharged photo imaging plate and transfers the at least partially recharged layer of liquid toner to a print substrate.

3. The liquid electrophotographic printer of claim 1, wherein a voltage is applied to the second charging element, and

wherein the applied voltage is tuned to adjust the recharging of the layer of liquid toner and photo imaging plate.

4. The liquid electrophotographic printer of claim 3, wherein the applied voltage is the same polarity as the charged layer of liquid toner.

5. The liquid electrophotographic printer of claim 3, wherein the applied voltage is tuned to enable substantially all of the at least partially recharged layer of liquid toner to be transferred to an intermediate transfer member.

6. The liquid electrophotographic printer of claim 3, wherein the applied voltage is tuned to enable substantially all of the charge on the at least partially recharged photo imaging plate to be retained on the photo imaging plate.

7. The liquid electrophotographic printer of claim 2, wherein the intermediate transfer member is grounded when the intermediate transfer member receives the at least partially recharged layer of liquid toner from the at least partially recharged photo imaging plate.

8. The liquid electrophotographic printer of claim 2, wherein the intermediate transfer member is grounded when the intermediate transfer member transfers the at least partially recharged layer of liquid toner to the print substrate.

9. The liquid electrophotographic printer of claim 1, wherein the print substrate is conductive.

10. The liquid electrophotographic printer of claim 1, wherein the print substrate is non-conductive.

11. A method of printing an image in a liquid electrophotographic printer, the method comprising:

at least partially discharging a charged photo imaging plate and a charged layer of liquid toner applied on the charged photo imaging plate;

at least partially recharging the layer of liquid toner and the photo imaging plate;

transferring the at least partially recharged layer of liquid toner from the at least partially recharged photo imaging plate to an intermediate transfer member, wherein the intermediate transfer member is grounded; and

transferring the at least partially recharged layer of liquid toner from the grounded intermediate transfer member to a print substrate.

12. The method of claim 11 further comprising:

applying a voltage to a charging element and;

tuning the applied voltage to adjust the recharging of the layer of liquid toner and photo imaging plate.

13. The method of claim 11 further comprising:

applying a voltage to a charging element, wherein the voltage is the same polarity as the charged layer of liquid toner.

14. The method of claim 12 further comprising:

tuning the applied voltage to enable at least one of;

substantially all of the at least partially recharged layer of liquid toner to be transferred to the grounded intermediate transfer member; and

substantially all of the charge on the at least partially recharged photo imaging plate to be retained on the photo imaging plate.

15. A non-transitory computer readable storage medium comprising a set of computer-readable instructions stored thereon, which, when executed by a processor, cause the processor to, in a liquid electrophotographic printer:

apply a first voltage to a first charging element to charge a photo imaging plate;

control a charge erasing element to at least partially discharge the charged photo imaging plate and to at least partially discharge a charged layer of liquid toner on the charged photo imaging plate;

apply a second voltage to a second charging element to at least partially recharge the layer of liquid toner and the photo imaging plate;

control an intermediate transfer member to receive the at least partially recharged layer of liquid toner from the at least partially recharged photo imaging plate; and

control the intermediate transfer member to transfer the at least partially recharged layer of liquid toner to a print substrate;

wherein the processor grounds the intermediate transfer member;

when the intermediate transfer member receives the at least partially recharged layer of liquid toner from the at least partially recharged photo imaging plate; and

when the intermediate transfer member transfers the at least partially recharged layer of liquid toner to the print substrate.