# US 5,708,944 A · Image forming apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,708,944 A
- Document ID: US5708944A
- Status: Granted
- Kind: A
- Application number: 08/716,480
- Filed: 1996-09-19
- Granted: 1998-01-13
- Earliest claimed: 1995-09-20
- Assignees: Fuji Xerox Co., Ltd.
- Inventors: Nobuo Hyakutake; Yuji Yokota; Yoshihiro Enomoto
- Web page: https://patentgrep.com/patent/US5708944A

## CPC

- G03G 15/1645: {Arrangements for controlling the amount of charge}
- G03G 2215/0177: Rotating set of developing units
- G03G 2215/1609: Corotron
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An image forming apparatus includes a control unit for forming an adsorb-charging region having a length along a paper transporting direction from a rear end of an image region on the recording paper adsorbed on the recording paper carrying/transporting member toward a backward direction by controlling operation-OFF timing of the adsorb-transferring charging means in such a manner that this operation-OFF timing is delayed from operation-OFF timing of the latent image forming unit, and this length of the adsorb-charging region becomes longer than, or equal to 1.5 mm.

## Claims

### Claim 1

An image forming apparatus, comprising:
latent image forming means for forming an electrostatic latent image;
an image carrier on which a toner image is formed by developing the latent image formed by said latent image forming means;
a recording paper carrying/transporting member arranged adjacent to a transfer position of this image carrier, for transporting a recording paper to which the toner image on the image carrier is transferred, while adsorbing said recording paper;
one adsorb-transferring charging means for performing an adsorb-charging operation for causing the recording paper to be adsorbed on said recording paper carrying/transporting member and a transfer-charging operation for transferring the toner image on the recording paper; and
control means for controlling operation-OFF timing of said adsorb-transferring charging means so that the operation-OFF timing is delayed from operation-OFF timing of said latent image forming means to form an adsorb-charging region having a predetermined length along the paper transporting direction from a rear end of an image region on the recording paper adsorbed on said recording paper carrying/transporting member backwardly.

### Claim 2 (depends on 1)

An image forming apparatus as claimed in claim 1, wherein the predetermined length of the adsorb-charging region formed by said control means is equal to or longer than 1.5 mm.

### Claim 3 (depends on 1)

An image forming apparatus as claimed in claim 1, wherein Said control means controls the operation-OFF timing of said latent image forming means and said adsorb-transferring charging means with a signal periodically produced in conjunction with a rotation of said recording paper carrying/transporting member as a reference signal.

### Claim 4 (depends on 1)

An image forming apparatus as claimed in claim 1, wherein said control means rotates the recording paper carrying/transporting member by 1 cycle only so as to adsorb such a recording paper having a non-fixed size when said recording paper having the non-fixed size whose length along the paper transporting direction is unknown is used, and controls the operation-OFF timing of said latent image forming means and said adsorb-transferring charging means, while the length of the recording paper having the non-fixed size along the paper transporting direction is sensed by paper size sensing means installed in a recording paper transporting path before an absorption.

### Claim 5 (depends on 1)

An image forming apparatus as claimed in claim 1 wherein when images are formed on both first and second surfaces of the recording paper, said control means performs such a control that a length of an adsorb-charging region along the paper transporting direction when the image is formed on the second surface is made longer than a length of an adsorb-charging region along the paper transporting direction when the image is formed on the first surface.