# US 4,394,431 A · Method for developing an electrostatic latent image with a liquid developer

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- Number: US 4,394,431 A
- Document ID: US4394431A
- Status: Granted
- Kind: A
- Application number: 06/307,523
- Filed: 1981-10-01
- Granted: 1983-07-19
- Earliest claimed: 1978-12-12
- Assignees: Canon Kabushiki Kaisha
- Inventors: Takashi Saito; Junichi Sakurayama; Tsuyoshi Watanabe
- Web page: https://patentgrep.com/patent/US4394431A

## CPC

- G03G 13/10: using a liquid developer {, e.g. liquid suspension}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A method for developing an electrostatic latent image comprising bringing a rigid member into pressure contact with a rotary member having a porous elastic member in the form of a layer provided in the periphery thereof to allow said elastic member to contain therein liquid developer in accordance with elastic deformation of the elastic member, urging said rotary member against an electrostatic latent image bearing surface and rotating said rotary member to supply the liquid developer to said bearing surface, thereby carrying out development of the electrostatic latent image, which comprises regulating the amount of elastic deformation of said elastic member in the direction of the thickness upon pressure contact thereof with said rigid member so as to be equivalent to or larger than that of said elastic member in the direction of the thickness upon pressure contact thereof with said bearing surface to conduct said development.

## Claims

### Claim 1

A method for developing an electrostatic latent image comprising the steps of bringing a rigid member into pressure contact with a rotary member having a porous elastic member in the form of a layer provided about the periphery thereof to cause said elastic member to be refreshed therein with liquid developer in accordance with the elastic deformation of the elastic member, urging said rotary member against an electrostatic latent image bearing surface and rotating said rotary member to supply the liquid developer to said bearing surface, thereby carrying out development of the electrostatic latent image, and regulating the amount of elastic deformation of said elastic member in the direction of its thickness produced by the pressure contact thereof with said rigid member to be equivalent to or larger than the elastic deformation of said elastic member in the direction of its thickness produced by the pressure contact thereof with said bearing surface.

### Claim 2 (depends on 1)

A method according to claim 1, in which said rotary member is brought into pressure contact with said bearing surface under a linear pressure of 100-800 g/cm.

### Claim 3 (depends on 1)

A method according to claim 1, in which said rotary member is capable of squeezing out liquid developer when said porous elastic member is compressed and absorbing the liquid developer when said porous elastic member is restored from the compressed state.

### Claim 4 (depends on 1)

A method according to claim 1, in which said elastic member is 1-10 mm thick.

### Claim 5 (depends on 1)

A method according to claim 1, in which the amount of elastic deformation of said elastic member in the direction of its thickness produced by the pressure contact thereof with the rigid member is regulated so as not to exceed 2/3 of the predetermined thickness of said elastic member.

### Claim 6 (depends on 1)

A method according to claim 1, in which said elastic member is controlled so as to have an Asker C hardness of 10-40, measured in accordance with the standard set by the Rubber Society of Japan, SRIS-0101-1968.