# US 2016/0259264 A1 · Image forming apparatus

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- Number: US 2016/0259264 A1
- Document ID: US20160259264A1
- Status: Published application
- Kind: A1
- Application number: 15/061,277
- Filed: 2016-03-04
- Published: 2016-09-08
- Earliest claimed: 2015-03-05
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Taisuke Matsuura
- Web page: https://patentgrep.com/patent/US20160259264A1

## CPC

- G03G 15/0266: {Arrangements for controlling the amount of charge}
- G03G 15/065: {Arrangements for controlling the potential of the developing electrode}
- G03G 15/1675: {with means for controlling the bias applied in the transfer nip}
- G03G 15/0189: {primary transfer to an intermediate transfer belt (G03G15/0184 takes precedence)}
- G03G 15/5037: {the characteristics being an electrical parameter, e.g. voltage}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An image forming apparatus includes a photosensitive member, a charging member, a charging voltage source, an exposure device, a developing device, a developing voltage source, a transfer member, a transfer voltage source, a detecting member, a setting portion for setting, a transfer voltage applied to the transfer member on the basis of a detection result of the detecting member, and an adjusting portion for increasing a potential difference between the potential of the photosensitive member charged and the developing voltage so as to be large when an absolute value of the transfer voltage set by the setting portion is a first threshold or more and an absolute value of the current flowing at the time of application of the transfer voltage to the transfer member is a second threshold or less.

## Claims

### Claim 1

An image forming apparatus comprising:
a photosensitive member;
a charging member for electrically charging said photosensitive member to a predetermined potential at a charging portion;
a charging voltage source for applying a voltage to said charging member;
an exposure device for exposing said photosensitive member to light to form an electrostatic image on said photosensitive member;
a developing device, including a developing sleeve for carrying a toner, for supplying the toner to the electrostatic image on said photosensitive member to form a toner image;
a developing voltage source for applying a developing voltage to said developing sleeve;
a transfer member for forming a transfer portion where the toner image is transferred from said photosensitive member onto a transfer receiving member;
a transfer voltage source for applying a voltage to said transfer member;
a detecting member for detecting information on the voltage and a current when the voltage is applied to said transfer member;
a setting portion for setting, on the basis of a detection result of said detecting member, a transfer voltage applied to said transfer member when the toner image is transferred from said photosensitive member onto the transfer receiving member at the transfer portion; and
an adjusting portion for increasing a potential difference between the potential of said photosensitive member charged and the developing voltage so as to be large when an absolute value of the transfer voltage set by said setting portion is a first threshold or more and an absolute value of the current flowing at the time of application of the transfer voltage to said transfer member is a second threshold or less.

### Claim 2 (depends on 1)

An image forming apparatus according to claim 1, wherein said adjusting portion adjusts the potential difference so as to be large by changing an absolute value of the voltage applied to said charging member by said charging voltage source so as to be large.

### Claim 3 (depends on 1)

An image forming apparatus according to claim 1, wherein said adjusting portion adjusts the potential difference so as to be large when a result of detection of a current value by said detecting member under application of the transfer voltage set by said setting portion to said transfer member is the second threshold or less.

### Claim 4 (depends on 1)

An image forming apparatus according to claim 1, wherein said adjusting portion adjusts the potential difference so as to be large on the basis of a relationship between a voltage value and a current value detected by said detecting member when a plurality of different voltages obtained when the transfer voltage is set by said setting portion are applied to said transfer portion.

### Claim 5 (depends on 1)

An image forming apparatus according to claim 1, wherein the first threshold is an upper limit value of the absolute value of the voltage outputted by said transfer voltage source.

### Claim 6 (depends on 1)

An image forming apparatus according to claim 1, further comprising a plurality of image forming units each including said photosensitive member, said charging member, said charging voltage source, said exposure device, said developing device, said developing voltage source, said transfer member and said transfer voltage source, said image forming units being arranged along a movement direction of the transfer-receiving member,
wherein said adjusting portion adjusts the potential difference so as to be large at least one of the image forming units disposed downstream of a most upstream image forming unit of said image forming units with respect to the movement direction of the transfer-receiving member.

### Claim 7 (depends on 1)

An image forming apparatus according to claim 1, wherein said charging voltage source applies a DC voltage containing no AC component to said charging member.

### Claim 8 (depends on 1)

An image forming apparatus according to claim 1, wherein a pre-exposure member for exposing said photosensitive member to light is not provided downstream of the transfer portion and upstream of the charging portion with respect to a movement direction of said photosensitive member.