# US 2010/0166440 A1 · Image Forming Apparatus

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- Number: US 2010/0166440 A1
- Document ID: US20100166440A1
- Status: Published application
- Kind: A1
- Application number: 12/647,082
- Filed: 2009-12-24
- Published: 2010-07-01
- Earliest claimed: 2008-12-26
- Assignees: Brother Kogyo Kabushiki Kaisha
- Inventors: Yoh NISHIMURA
- Web page: https://patentgrep.com/patent/US20100166440A1

## CPC

- G03G 15/5058: {using a test patch}
- G03G 15/065: {Arrangements for controlling the potential of the developing electrode}
- G03G 15/556: {for toner consumption, e.g. pixel counting, toner coverage detection or toner density measurement}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An image forming apparatus includes: an image carrier; a developing housing that accommodates a developer for developing an electrostatic latent image into a developer image; a developer carrier, which carries the developer in the developing housing, and which supplies the developer to the image carrier; a developing bias supply part that supplies a developing bias to the developer carrier; a remaining quantity calculation part that calculates a remaining quantity of the developer in the developing housing; a deterioration grade storage part that stores a relationship between the remaining quantity of the developer in the developing housing and a deterioration degree of the developer caused by the developing operation; and a developing bias setting part that sets a value of the developing bias in accordance with the remaining quantity calculated by the remaining quantity calculation part and the relationship stored in the deterioration grade storage part.

## Claims

### Claim 1

An image forming apparatus, which executes a developing operation for forming a developer image, and which forms an image comprising the developer image on a recording medium, the image forming apparatus comprising:
an image carrier, on which an electrostatic latent image is formed;
a developing housing that accommodates a developer for developing the electrostatic latent image into a developer image;
a developer carrier, which is held by the developing housing, which carries the developer in the developing housing, and which supplies the developer to the image carrier;
a developing bias supply part that supplies a developing bias to the developer carrier;
a remaining quantity calculation part that calculates a remaining quantity of the developer in the developing housing;
a deterioration grade storage part that stores a relationship between the remaining quantity of the developer in the developing housing and a deterioration degree of the developer caused by the developing operation; and
a developing bias setting part that sets a value of the developing bias in accordance with the remaining quantity calculated by the remaining quantity calculation part and the relationship stored in the deterioration grade storage part.

### Claim 2 (depends on 1)

The image forming apparatus according to claim 1,
wherein the remaining quantity calculation part calculates the remaining quantity at each predetermined timing, and
wherein the developing bias setting part sets the value of the developing bias every time the remaining quantity calculation part calculates the remaining quantity.

### Claim 3 (depends on 2)

The image forming apparatus according to claim 2, wherein the remaining quantity calculation part calculates the remaining quantity in each developing operation.

### Claim 4 (depends on 1)

The image forming apparatus according to claim 1, further comprising:
a dot counter that counts the number of dots of the image formed on the recording medium,
wherein the remaining quantity calculation part calculates the remaining quantity of the developer in the developing housing based on the number of dots counted by the dot counter.

### Claim 5 (depends on 1)

The image forming apparatus according to claim 1, further comprising:
a deterioration quantity calculation part, which calculates the deterioration degree of the developer based on the relationship stored in the deterioration grade storage part, and which calculates a deterioration quantity of the developer by integrating the calculated deterioration degrees every time the remaining quantity calculation part calculates the remaining quantity of the developer,
wherein the developing bias setting part sets the developing bias to a value corresponding to the deterioration quantity calculated by the deterioration quantity calculation part.

### Claim 6 (depends on 1)

The image forming apparatus according to claim 1, further comprising:
a developing operation prohibition part that prohibits execution of subsequent developing operations when the deterioration quantity calculated by the deterioration quantity calculation part exceeds a threshold value.