Image forming apparatus

Patent metadata

Field	Value
Publication number	US-2021041800-A1
Application number	US-202016986265-A
Country	US
Kind code	A1
Filing date	Aug 6, 2020
Priority date	Aug 9, 2019
Publication date	Feb 11, 2021
Grant date	—

Abstract

An image forming apparatus includes a photoconductor, a charger, a charge remover, and control circuitry. The charger is configured to charge the photoconductor. The charge remover is configured to remove charge from a surface of the photoconductor by light and electric discharge. The control circuitry is configured to: estimate a surface potential that the photoconductor has after the photoconductor is charged by the charger, based on a characteristic value of the photoconductor and a value of a current flowing through the charger after the charge remover removes charge from the photoconductor; and control a charging bias applied to the charger, based on the surface potential estimated.

First claim

1 . An image forming apparatus comprising:
a photoconductor; a charger configured to charge the photoconductor; a charge remover configured to remove charge from a surface of the photoconductor by light and electric discharge; and control circuitry configured to:
estimate a surface potential that the photoconductor has after the photoconductor is charged by the charger, based on a characteristic value of the photoconductor and a value of a current flowing through the charger after the charge remover removes charge from the photoconductor; and
control a charging bias applied to the charger, based on the surface potential estimated.

2 . The image forming apparatus according to claim 1 ,
wherein the control circuitry is configured to:
estimate a residual potential that the photoconductor has after the charge remover removes charge from the surface of the photoconductor only by light, based on a value of a current flowing through the charger when the charger charges the photoconductor after the charge remover removes charge from the surface of the photoconductor by light and electric discharge, a value of a current flowing through the charger when the charger charges the photoconductor after the charge remover removes charge from the surface of the photoconductor only by light, and the characteristic value of the photoconductor; and
adjust image forming conditions based on the residual potential estimated.

3 . The image forming apparatus according to claim 1 ,
wherein the control circuitry is configured to cause the charge remover to remove charge from the photoconductor by light and electric discharge for two or more rotations of the photoconductor.

4 . The image forming apparatus according to claim 1 ,
wherein the control circuitry is configured to perform an operation of acquiring the characteristic value of the photoconductor through repeatedly performing a cycle of charge removal by the charge remover and charging by the charger, and an operation of estimating a charge potential of the photoconductor through performing only once the cycle of charge removal by the charge remover and charging by the charger.

5 . The image forming apparatus according to claim 4 ,
wherein the operation of acquiring the characteristic value of the photoconductor is an operation of measuring, a plurality of times, a value of a current flowing through the charger when the charger charges the photoconductor after the charge remover removes charge from the photoconductor by light and electric discharge while changing the charging bias applied to the charger.

6 . The image forming apparatus according to claim 4 ,
wherein the control circuitry is configured to perform the operation of acquiring the characteristic value of the photoconductor in a case where a specific condition is satisfied.

7 . The image forming apparatus according to claim 6 ,
wherein the specific condition is a condition whose occurrence frequency is less than an occurrence frequency of the operation of estimating the charge potential of the photoconductor.

8 . The image forming apparatus according to claim 6 ,
wherein the case where the specific condition is satisfied is a case where the photoconductor is replaced.

9 . The image forming apparatus according to claim 6 ,
wherein the case where the specific condition is satisfied is a case where a use environment is changed by a predetermined amount or more.

10 . The image forming apparatus according to claim 6 ,
wherein the case where the specific condition is satisfied is a case where the photoconductor is used by a predetermined amount or more.

11 . The image forming apparatus according to claim 6 , further comprising:
a current detector configured to detect a value of a current flowing through the charger; and a charging power supply configured to apply the charging bias to the charger, wherein the case where the specific condition is satisfied is a case where the charging power supply is replaced,

12 . The image forming apparatus according to claim 1 ,
wherein the characteristic value of the photoconductor is an amount of change in charge potential with respect to an amount of change in charging current.

13 . The image forming apparatus according to claim 1 , further comprising a charging power supply configured to apply the charging bias to the charger,
wherein the charging power supply is configured to generate a direct current and an alternating current, and wherein the charging power supply is configured to apply an alternating current bias to the charger to cause the charge remover to remove charge from the surface of the photoconductor.

Assignees

• Kosuge Akio
• Suzuki Yuji
• Takahashi Daisuke
• Akatsu Shinichi
• Ito Daisuke
• Ricoh Co Ltd

Inventors

• Kosuge Akio
• Suzuki Yuji
• Takahashi Daisuke
• Akatsu Shinichi
• Ito Daisuke

Classifications

• G03G15/0266 Primary

  Arrangements for controlling the amount of charge · CPC title

• G03G15/05 Primary

  for imagewise charging, e.g. photoconductive control screen or optically activated charging means · CPC title

• G03G15/0291

  corona discharge devices, e.g. wires, pointed electrodes, means for cleaning the corona discharge device · CPC title

• G03G21/08

  using optical radiation · CPC title