Image forming apparatus with cleaning using cleaning member and charging member

Patent metadata

Field	Value
Publication number	US-9599935-B2
Application number	US-201615007597-A
Country	US
Kind code	B2
Filing date	Jan 27, 2016
Priority date	Jan 29, 2015
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

In an adjustment step, an adjustment purpose toner image is formed on an intermediate transfer belt, and the adjustment purpose toner image is removed from the intermediate transfer belt by a cleaning member contacting the intermediate transfer belt and through an electrostatic cleaning step. This adjustment step is executed in a state where a toner attachment amount on a charging member is switched from a first limit value, which is allowed in the image forming step to a second limit value, which is allowed immediately before executing the adjustment step. This switching is performed by the execution of a toner discharging step, where a power supply changes the state of applying voltage to the charging member from that in the electrostatic cleaning step, so that toner attached to the charging member is transferred to the intermediate transfer belt.

First claim

What is claimed is:

1. An image forming apparatus, comprising:
an image bearing member configured to bear a toner image that is formed by an electrostatic latent image being developed using toner;
an intermediate transfer belt configured such that a toner image is transferred from the image bearing member;
a cleaning member configured to remove toner from the intermediate transfer belt by contacting the intermediate transfer belt;
a charging member configured to charge toner borne on the intermediate transfer belt; and
a power supply configured to apply voltage, which is required for the charging member to charge toner, to the charging member,
wherein the image forming apparatus is configured to execute:
an image forming step in which an image is formed on a recording material by transferring a toner image, which is transferred from the image bearing member to the intermediate transfer belt, to the recording material;
an electrostatic cleaning step in which the power supply applies voltage, which has reversed polarity of the polarity used upon charging toner to develop an electrostatic latent image, to the charging member, and the charging member charges the toner borne on the intermediate transfer belt to have the reversed polarity so that the toner is transferred from the intermediate transfer belt to the image bearing member, and the toner is removed from the intermediate transfer belt;
a toner discharging step in which the power supply changes a state of applying voltage to the charging member from that in the electrostatic cleaning step, so that the toner attached to the charging member is transferred to the intermediate transfer belt; and
an adjustment step in which an adjustment-purpose toner image, which is not transferred to a recording material, is formed on the intermediate transfer belt, and the adjustment-purpose toner image is removed from the intermediate transfer belt by the cleaning member and through the electrostatic cleaning step,
wherein the adjustment step is executed in a state where a toner attachment amount of the charging member is switched from a first limit value, which is allowed in the image forming step, to a second limit value, which is allowed immediately before executing the adjustment step, by the execution of the toner discharging step.

2. The image forming apparatus according to claim 1 , wherein the second limit value is a value by which the toner attachment amount immediately after the end of the adjustment step becomes the first limit value or less.

3. The image forming apparatus according to claim 1 , wherein the second limit value is a value lower than the first limit value.

4. The image forming apparatus according to claim 1 , wherein
the toner discharging step is performed by the power supply alternately switching a state of applying voltage to the charging member between a first state and a second state which is different from the first state, and
the number of times when the power supply switches the voltage applying state is less in a first toner discharging step, which is executed immediately before the image forming step, than a second toner discharging step, which is executed immediately before the adjustment step.

5. The image forming apparatus according to claim 4 , wherein
the adjustment step is executed after executing the image forming step for a plurality of times, and
the number of times of switching the voltage applying state in the first toner discharging step is the number of times that allows the toner attachment amount to be maintained so as not to reach the first limit value until the second toner discharging step is executed.

6. The image forming apparatus according to claim 5 , wherein the number of times of switching in the first toner discharging step, which is executed immediately before each of the plurality of times of the image forming step, is the same each time.

7. The image forming apparatus according to claim 4 , wherein the voltage value which the power supply applies to the charging member is different between the first state and the second state.

8. The image forming apparatus according to claim 4 , wherein one of the first state and the second state is a state of the power supply applying voltage to the charging member (ON), and the other is a state of the power supply not applying voltage to the charging member (OFF).

9. The image forming apparatus according to claim 4 , wherein the polarity of the voltage which power supply applies to the charging member is different between the first state and the second state.

10. The image forming apparatus according to claim 1 , further comprising:
a cartridge configured to be detachable from an apparatus main body of the image forming apparatus, the cartridge including:
the image bearing member;
a developer bearing member configured to bear toner for developing an electrostatic latent image formed on the image bearing member;
a developer supplying member configured to supply toner to the developer bearing member; and
a developer container configured to contain toner which the developer supplying member supplies to the developer bearing member; and

a detection unit configured to detect that the cartridge is new,
wherein the adjustment step, which is initially executed after the detection unit detects that the cartridge is new, is executed in a state where the toner attachment amount is reduced, by the execution of the toner discharging step, to a third limit value or less that is allowed in a state immediately before the execution of the adjustment step which is initially executed.

11. The image forming apparatus according to claim 10 , wherein the third limit value is a value by which the toner attachment amount, immediately after the end of the adjustment step initially executed, becomes the first limit value or less.

12. The image forming apparatus according to claim 10 , wherein the number of times of the power supply switching the voltage applying state is higher in the third toner discharging step which is executed immediately before the adjustment step initially executed, than in the first toner discharging step which is executed immediately before the image forming step.

13. The image forming apparatus according to claim 10 , wherein the number of times of the power supply switching the voltage applying state is higher in the third toner discharging step which is executed immediately before the adjustment step initially executed, than in the second toner discharging step which is executed immediately before the adjustment step which is executed thereafter.

14. The image forming apparatus according to claim 10 , wherein the developer container includes:
an opening for feeding the contained toner to the developer supplying member; and
a sealing member which seals the opening when the cartridge is new, and which is removed from the opening to open the opening when the new cartridge is installed to the image forming apparatus main body, and
the third toner discharging step, which is executed immediately before the adjustment step initially executed, is executed while the sealing member is being removed from the opening.

15. The image forming apparatus according to claim 1 , wherein the adjustment-purpose toner image is a toner image for adjusting an image density or for adjusting an image position.

Assignees

• Canon Kk

Inventors

• Asai Masanori
• Funatani Kazuhiro
• Seki Hiroyuki
• Saito Shuji
• Yagi Yasutaka
• Fujimoto Tetsuichiro

Classifications

• G03G2215/0132

  vertical medium transport path at the secondary transfer · CPC title

• G03G15/161 Primary

  with means for handling the intermediate support, e.g. heating, cleaning, coating with a transfer agent · CPC title

• G03G2221/001

  Plural sequential cleaning devices · CPC title

• G03G21/0076

  Plural or sequential cleaning devices · CPC title