# US 2017/0255133 A1 · Image forming apparatus

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- Number: US 2017/0255133 A1
- Document ID: US20170255133A1
- Status: Published application
- Kind: A1
- Application number: 15/446,130
- Filed: 2017-03-01
- Published: 2017-09-07
- Earliest claimed: 2016-03-04
- Assignees: Konica Minolta, Inc.
- Applicants: Konica Minolta, Inc.
- Inventors: AIKO KUBOTA; TAKAAKI KOORIYA; TORU YAMAGUCHI
- Web page: https://patentgrep.com/patent/US20170255133A1

## CPC

- G03G 15/1605: {using at least one intermediate support (G03G15/1625 takes precedence)}
- G03G 15/0189: {primary transfer to an intermediate transfer belt (G03G15/0184 takes precedence)}
- G03G 15/1685: {Structure, details of the transfer member, e.g. chemical composition}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An image forming apparatus includes: a primary transfer unit configured to transfer a toner image formed on an image carrier onto an intermediate transfer belt through primary transfer; and a secondary transfer unit configured to transfer the toner image formed on the intermediate transfer belt onto a recording medium through secondary transfer, wherein the secondary transfer unit extends along a width direction of the recording medium and includes a roller pair and a switching unit, the roller pair being configured to nip the intermediate transfer belt and the recording medium such that the intermediate transfer belt and the recording medium are in pressure contact with each other, the switching unit being configured to switch a length of at least one of the roller pair in a shaft direction.

## Claims

### Claim 1

An image forming apparatus comprising: a primary transfer unit configured to transfer a toner image formed on an image carrier onto an intermediate transfer belt through primary transfer; and
a secondary transfer unit configured to transfer the toner image formed on the intermediate transfer belt onto a recording medium through secondary transfer,
wherein the secondary transfer unit extends along a width direction of the recording medium and includes a roller pair and a switching unit, the roller pair being configured to nip the intermediate transfer belt and the recording medium such that the intermediate transfer belt and the recording medium are in pressure contact with each other, the switching unit being configured to switch a length of at least one of the roller pair in a shaft direction.

### Claim 2 (depends on 1)

The image forming apparatus according to claim 1,
wherein the switching unit switches the length of the at least one of the roller pair to a length shorter than a width of the recording medium that is a length of the recording medium in the width direction perpendicular to a conveyance direction of the recording medium.

### Claim 3 (depends on 1)

The image forming apparatus according to claim 1, wherein the switching unit includes:
a rotatable member including a plurality of rollers having different lengths in the shaft direction from each other and a supporting portion that rotatably supports the plurality of rollers and is rotatable about a shaft parallel to the shaft direction; and
a control unit that selects one roller from the plurality of rollers in accordance with a width of the recording medium and rotates the supporting portion to cause the one roller to oppose the intermediate transfer belt, and
the one roller is one of the roller pair.

### Claim 4 (depends on 3)

The image forming apparatus according to claim 3,
wherein the roller pair includes a driving roller over which the intermediate transfer belt is stretched and a driven roller that is driven along with the driving roller, and
the one roller is the driven roller.

### Claim 5 (depends on 3)

The image forming apparatus according to claim 3,
wherein the roller pair includes a first driving roller over which the intermediate transfer belt is stretched and a second driving roller that drives together with the first driving roller,
the one roller is the second driving roller, and
the secondary transfer unit includes a retracting mechanism that moves the rotatable member away from the intermediate transfer belt.

### Claim 6 (depends on 1)

The image forming apparatus according to claim 1, further comprising a sorting control unit that, in a case where image formation is successively performed on recording media having different widths, changes an order of image formation such that image formation is successively performed on recording media having the same width.

### Claim 7 (depends on 1)

The image forming apparatus according to claim 1, further comprising a voltage control unit that performs voltage control of determining a value of voltage corresponding to a value of an electric resistance of the roller pair at a predetermined frequency, and, in a case where the length of the at least one of the roller pair has been switched, changes the frequency of performing the voltage control in accordance with the length of the at least one of the roller pair after switching until a temperature of the at least one of the roller pair after switching reaches a set temperature.