Cleaning bias voltage control

Patent metadata

Field	Value
Publication number	US-12105447-B2
Application number	US-202118033027-A
Country	US
Kind code	B2
Filing date	Jun 18, 2021
Priority date	Oct 27, 2020
Publication date	Oct 1, 2024
Grant date	Oct 1, 2024

Abstract

An example image forming apparatus includes a power device, a photosensitive drum, a transfer device to remove remaining toner based on a cleaning bias voltage, an optical sensor to detect remaining toner, and a processor to adjust the cleaning bias voltage based on a set offset bias voltage. The processor may change a surface potential of the photosensitive drum to a voltage of a set pattern using the power device, acquire a size ratio of a periodic component based on a frequency of a signal detected from the remaining toner using the optical sensor, and, based on the acquired size ratio of the periodic component being greater than or equal to a set size ratio, adjust the cleaning bias voltage based on an offset bias voltage corresponding to the size ratio of the periodic component and provide the adjusted cleaning bias voltage to the transfer device to remove remaining toner.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a power device;
a photosensitive drum;
a transfer device to remove remaining toner based on a cleaning bias voltage provided from the power device;
an optical sensor to detect remaining toner of the transfer device or the photosensitive drum; and
a processor to:
change a surface potential of the photosensitive drum to a voltage of a set pattern by using the power device,
acquire a size ratio according to a periodic component of a signal determined by the optical sensor, the signal indicative of the remaining toner of the transfer device, based on a frequency of the signal detected from the remaining toner by using the optical sensor,
based on the acquired size ratio according to the periodic component being greater than or equal to a set size ratio, adjust the cleaning bias voltage based on an offset bias voltage corresponding to the acquired size ratio according to the periodic component,
provide the adjusted cleaning bias voltage to the transfer device by using the power device to remove the remaining toner, and
based on the acquired size ratio according to the periodic component being less than the set size ratio, provide the cleaning bias voltage to the transfer device by using the power device to remove the remaining toner.

2. The image forming apparatus of claim 1 , wherein the processor is to provide the voltage of the set pattern by changing at least one of a voltage application cycle, a voltage size, or a set number of times of applying a voltage to the photosensitive drum by using the power device.

3. The image forming apparatus of claim 2 , wherein the processor is to display an exposure marker that distinguishes a start and an end of an operation of detecting the remaining toner at a starting point and an ending point of providing the voltage of the set pattern.

4. The image forming apparatus of claim 1 , wherein the processor is to detect the remaining toner at a time point of warming-up or a time point of tone reproduction curve (TRC) of the image forming apparatus.

5. The image forming apparatus of claim 1 , wherein the offset bias voltage includes a bias voltage to reduce an absolute value of the cleaning bias voltage.

6. The image forming apparatus of claim 1 , further comprising:
a memory to store an offset table including a size ratio of the periodic component and the offset bias voltage corresponding to the size ratio of the periodic component.

7. The image forming apparatus of claim 1 , wherein the offset bias voltage changes according to the acquired size ratio of the periodic component, a printing speed, a temperature of a surrounding environment of a location of the image forming apparatus, or the humidity of the surrounding environment of the location of the image forming apparatus.

8. The image forming apparatus of claim 7 , wherein the offset bias voltage is represented as a positive correlation with at least one of the temperature or the humidity of the surrounding environment of the location of the image forming apparatus.

9. A method of controlling a cleaning bias voltage, the method comprising:
changing a surface potential of a photosensitive drum to a voltage of a set pattern;
acquiring a size ratio according to a periodic component of a signal determined by an optical sensor, the signal indicative of remaining toner of a transfer device, based on a frequency of the signal detected from the transfer device or the photosensitive drum to detect the remaining toner;
based on the acquired size ratio according to the periodic component being greater than or equal to a set size ratio, adjusting a cleaning bias voltage for removing the remaining toner based on an offset bias voltage corresponding to the acquired size ratio according to the periodic component;
providing the adjusted cleaning bias voltage to the transfer device to remove the remaining toner; and
based on the acquired size ratio according to the periodic component being less than the set size ratio, providing the cleaning bias voltage to the transfer device by using the power device to remove the remaining toner.

10. The method of controlling a cleaning bias voltage of claim 9 , wherein the changing of the surface potential of the photosensitive drum comprises:
providing the voltage of the set pattern by changing at least one of a voltage application cycle, a voltage size, or a set number of times of applying a voltage to the photosensitive drum.

11. The method of controlling a cleaning bias voltage of claim 10 , wherein the changing of the surface potential of the photosensitive drum comprises:
displaying an exposure marker to distinguish a start and an end of an operation of detecting the remaining toner at a starting point and an ending point of providing the voltage of the set pattern.

12. The method of controlling a cleaning bias voltage of claim 9 , wherein the detecting of the remaining toner of the transfer device is performed at a time point of warming-up or a time point of tone reproduction curve (TRC) of the image forming apparatus.

13. The method of controlling a cleaning bias voltage of claim 9 , wherein the offset bias voltage includes a bias voltage which reduces an absolute value of the cleaning bias voltage.

14. The method of controlling a cleaning bias voltage of claim 9 , wherein the offset bias voltage changes according to the acquired size ratio of the periodic component, the printing speed, a temperature of a surrounding environment of a location of the image forming apparatus, or a humidity of the surrounding environment of the location of the image forming apparatus.

15. A non-transitory computer-readable recording medium including a program to perform a method of controlling a cleaning bias voltage, the non-transitory computer-readable recording medium comprising:
instructions to change a surface potential of a photosensitive drum to a voltage of a set pattern;
instructions to acquire a size ratio according to a periodic component of a signal determined by an optical sensor, the signal indicative of remaining toner of transfer device, based on a frequency of the signal detected from the transfer device or the photosensitive drum to detect the remaining toner;
instructions to, based on the acquired size ratio according to the periodic component being greater than or equal to a set size ratio, adjust a cleaning bias voltage for removing the remaining toner based on an offset bias voltage corresponding to the acquired size ratio according to the periodic component;
instructions to provide the adjusted cleaning bias voltage to the transfer device to remove the remaining toner; and
instructions to, based on the acquired size ratio according to the periodic component being less than the set size ratio, provide the cleaning bias voltage to the transfer device by using the power device to remove the remaining toner.

Assignees

• Hewlett Packard Development Co

Inventors

• Song Jung Hun
• Kim Do Geun
• Kim Jeong Hwan

Classifications

• G03G15/5037 Primary

  the characteristics being an electrical parameter, e.g. voltage · CPC title

• G03G15/1675

  with means for controlling the bias applied in the transfer nip · CPC title

• G03G2221/0005

  Cleaning of residual toner · CPC title

• G03G2215/00978

  Details relating to power supplies · CPC title

• G03G2215/00025

  Machine control, e.g. regulating different parts of the machine · CPC title