Electrophotographic apparatus including a plurality of developing agent image forming units and a method of forming an electrophotographic image

• US 6,336,021 B1
• Filed: 03/23/2000
• Issued: 01/01/2002
• Est. Priority Date: 03/26/1999
• Status: Expired due to Term

• Current Assignee: Toshiba Tec Corporation (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nukada, Hideki
• Primary Examiner(s): Braun, Fred L
• Assistant Examiner(s): TRAN, HOAN H
• Application Number:
  US09/533,931
• Time in Patent Office: 649 Days
• Field of Search: 399/57, 399/237, 399/239, 399/240, 399/249, 152/565.1, 430/117, 430/118, 430/260, 430/261
• US Class Current: 399/249
• CPC Class Codes: G03G 15/11 Removing excess liquid developer, e.g. by heat
• CPC Class Codes: G03G 2215/017 single rotation of recording member to produce multicoloured copy
• CPC Class Codes: G03G 2215/0629 liquid at room temperature

Abstract

Disclosed are an electrophotographic apparatus and a method for forming an electrophotographic image, in which a solvent recovery surface is rotated in a direction opposite to a moving direction of an image-holding surface having a liquid developer containing a toner and a solvent supplied thereto at a speed 1 to 4 times as high as the rotating speed of the image-holding surface such that the solvent recovery surface is apart from the image holding surface and in contact with the solvent attached to the image-holding surface at the position where these solvent recovery surface and image-holding surface are closest to each other, so as to remove at least partially the solvent from the image-holding surface.

Claims

1. A color electrophotographic apparatus, comprising:

an image holder having a movable image-holding surface;

a plurality of developing agent image forming units each comprising a latent image forming device configured to form a latent image on the image-holding surface, a developing device configured to form an image of a developing agent on the image-holding surface by supplying a liquid developer containing a toner and a solvent onto the image-holding surface having the latent image formed thereon, and a solvent recovery device including a solvent recovery surface and configured to recover at least partially the solvent from the image-holding surface, the solvent recovery surface being apart from the image-holding surface and in contact with the solvent attached to the image-holding surface in a position closest to the image-holding surface and moving in a direction opposite to a moving direction of the image-holding surface at the position closest to the image-holding surface, the latent image forming device, the developing device and the solvent recovery device facing the image-holding surface in the order mentioned in the moving direction of the image-holding surface;

a transfer unit facing the image-holding surface and configured to transfer the developing agent images from the image-holding surface onto a transfer material; and

a control unit connected to each of the solvent recovery devices and configured to control each moving speed of the solvent recovery-surfaces at 1 to 4 times as high as the moving speed of the image-holding surface.

2. An apparatus according to claim 1, wherein each of the solvent recovery devices comprises a roller having the solvent recovery surface.

3. An apparatus according to claim 2, wherein each of the solvent recovery devices further comprises a removing member configured to remove the solvent attached to the solvent recovery surface.

4. An apparatus according to claim 1, wherein the image holder is a photoconductor drum.

5. An apparatus according to claim 1, wherein the latent image is an electrostatic latent image.

6. An apparatus according to claim 5, wherein each of the solvent recovery devices further comprises a voltage application mechanism configured to apply a voltage of a polarity opposite to the charged polarity of the toner to the solvent recovery surface.

7. An apparatus according to claim 1, wherein the plural developing agent image forming units consists of four developing agent image forming units forming a yellow developing agent image, a magenta developing agent image, a cyan developing agent image and a black developing agent image, respectively.

8. An apparatus according to claim 1, wherein the developing agent image forming units are configured to form a composite color image comprising the developing agent images on the image-holding surface, and the transfer unit is configured to transfer the composite color image from the image-holding surface onto the transfer material.

9. A color electrophotographic apparatus, comprising:

an image holder having a movable image-holding surface;

a plurality of developing agent image forming units each comprising a latent image forming device configured to form a latent image on the image-holding surface, a developing device configured to form an image of a developing agent on the image-holding surface by supplying a liquid developer containing a toner and a solvent onto the image-holding surface having the latent image formed thereon, and a solvent recovery device including a solvent recovery surface and configured to recover at least partially the solvent from the image-holding surface, the solvent recovery surface being apart from the image-holding surface and in contact with the solvent attached to the image-holding surface in a position closest to the image-holding surface, moving in a direction opposite to a moving direction of the image-holding surface at the position closest to the image-holding surface, and having a curvature radius of 5 mm to 11 mm, the latent image forming device, the developing device and the solvent recovery device facing the image-holding surface in the order mentioned in the moving direction of the image-holding surface;

a transfer unit facing the image-holding surface and configured to transfer the developing agent images from the image-holding surface onto a transfer material; and

a control unit connected to the solvent recovery device and configured to control the moving speed of the solvent recovery surface at 1 to 4 times as high as the moving speed of the image-holding surface.

10. An apparatus according to claim 9, wherein the image-holding surface has a curvature radius of 50 mm to 135 mm at the position closest to the solvent recovery surface.

11. An apparatus according to claim 10, wherein the distance between the solvent recovery surface and the image-holding surface is 25 μ

m to 100 μ

m where these solvent recovery surface and image-holding surface are positioned closest to each other.

12. An apparatus according to claim 11, wherein the image holder is a photoconductor drum and the solvent recovery device comprises a roller having the solvent recovery surface.

13. An apparatus according to claim 9, wherein the distance between the solvent recovery surface and the image-holding surface is 25 μ

m to 100 μ

m where these solvent recovery surface and image-holding surface are positioned closest to each other.

14. An apparatus according to claim 9, therein the developing agent image forming units are configured to form a composite color image comprising the developing agent images on the image-holding surface, and the transfer unit is configured to transfer the composite color image from the image-holding surface onto the transfer material.

15. A color electrophotographic apparatus, comprising:

an image holder having a movable image-holding surface;

a plurality of developing agent image forming units each comprising a latent image forming device configured to form a latent image on the image-holding surface, a developing device configured to form an image of a developing agent on the image-holding surface by supplying a liquid developer containing a toner and a solvent onto the image-holding surface having the latent image formed therein, and a solvent recovery device including a solvent recovery surface and configured to recover at least partially the solvent from the image-holding surface, the solvent recovery surface being apart from the image-holding surface by 25 μ

m 100 μ

m and in contact with the solvent attached to the image-holding surface in a position closest to the image-holding surface and moving in a direction opposite to a moving direction of the image-holding surface at the position closest to the image-holding surface, the latent image forming device, the developing device and the solvent recovery device facing the image-holding surface in the order mentioned in the moving direction of the image-holding surface;

a transfer unit facing the image-holding surface and configured to transfer the developing agent images from the image-holding surfaces onto a transfer material; and

a control unit connected to each of the solvent recovering device and configured to control each moving speed of the solvent recovery surfaces at 1 to 4 times as high as the moving speed of the image-holding surface.

16. An apparatus according to claim 15, wherein the developing agent image forming units are configured to form a composite color image comprising the developing agent images on the image-holding surface, and the transfer unit is configured to transfer the composite color image from the image-holding surface onto the transfer material.

17. A method of forming an electrophotographic image, comprising:

forming a first electrostatic latent image on an image-holding surface being moving;

supplying a first liquid developer containing a first toner and a first solvent onto the image-holding surface having the first latent image formed thereon to form a first developing agent image containing the first toner;

moving a first solvent recovery surface in a direction opposite to the moving direction of the image-holding surface at a speed 1 to 4 times as high as the moving speed of the image-holding surface such that the first solvent recovery surface is apart from the image-holding surface and in contact with the first solvent attached to the image-holding surface in a position closest to the image-holding surface, thereby recovering at least partially the solvent from the image-holding surface;

forming a second electrostatic latent image on the image-holding surface being moving and having the first solvent recovered at least partially therefrom;

supplying a second liquid developer containing a second toner and a second solvent onto the image-holding surface having the second electrostatic latent image formed thereon to form a composite color image comprising the first developing agent image and a second developing agent image containing the second toner;

moving a second solvent recovery surface in a direction opposite to the moving direction of the image-holding surface at a speed 1 to 4 times as high as the moving speed of the image-holding surface such that the second solvent recovery surface is apart from the image-holding surface and in contact with the second solvent attached to the image-holding surface in a position closest to the image-holding surface, thereby recovering at least partially the second solvent from the image-holding surface; and

transferring the composite color image from the image-holding surface onto a transferring material.