Image forming apparatus

Patent metadata

Field	Value
Publication number	US-12416894-B2
Application number	US-202318400097-A
Country	US
Kind code	B2
Filing date	Dec 29, 2023
Priority date	Jan 30, 2023
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

An image forming apparatus includes a toner image bearer, a transfer device, a cleaner, a bias power source, and circuitry. The toner image bearer bears a toner image. The transfer device performs a transfer process. The cleaner contacts the toner image bearer to remove transfer residual toner that is subject to the transfer process and remove untransferred toner that is not subject to the transfer process. The bias power source applies one of a first bias and a second bias different from the first bias to the cleaner. The circuitry controls the bias power source to output the first bias to the cleaner in response to a start of an image forming operation to remove the untransferred toner from the toner image bearer and control the bias power source to switch an output from the first bias to the second bias.

First claim

The invention claimed is:

1. An image forming apparatus comprising:
a toner image bearer configured to bear a toner image formed by an image forming operation;
a transfer device configured to perform a transfer process to transfer the toner image from the toner image bearer to a sheet;
multiple cleaners contacting the toner image bearer and having different resistance values with each other, the multiple cleaners including at least
a first cleaner having a first resistance, and
a second cleaner having a second resistance greater than the first resistance,

wherein the multiple cleaners are configured to
remove transfer residual toner on the toner image bearer that is subject to the transfer process, and
remove untransferred toner on the toner image bearer that is not subject to the transfer process;

multiple bias power sources configured to apply one of a first bias or a second bias to the multiple cleaners, respectively, the second bias being larger than the first bias, the multiple bias power sources including
a first bias power source configured to apply the first bias to the first cleaner, and
a second bias power source configured to apply the first bias to the second cleaner; and

circuitry configured to
control the first bias power source to output the first bias to the first cleaner in response to a start of the image forming operation to remove the untransferred toner from the toner image bearer, and
control the first bias power source to switch an output from the first bias to a third bias, different from the first bias, to remove the transfer residual toner from the toner image bearer.

2. The image forming apparatus according to claim 1 , further comprising:
a sensor configured to detect a temperature,
wherein the circuitry is further configured to determine the first bias and the third bias based on the temperature detected by the sensor.

3. The image forming apparatus according to claim 1 , further comprising:
a motor rotatable at different linear velocities to drive the toner image bearer and the multiple cleaners,
wherein the circuitry is further configured to change at least one of the first bias or the second bias based on the different linear velocities of the motor.

4. The image forming apparatus according to claim 1 ,
wherein the circuitry is further configured to determine the first bias applied to the first cleaner at the start of the image forming operation, according to the expression

First
⁢

bias

[
V
]

=

basic
⁢

value

[
V
]

×
temperature
⁢

correction
⁢

⁢

coefficient

[
%
]

/
100
×
linear
⁢

velocity
⁢

correction
⁢

coefficient

[
%
]

⁠
/
100
×
untransferred
⁢

toner
⁢

correction
⁢

coefficient

[
%
]

/
100.

5. The image forming apparatus according to claim 4 ,
wherein the first cleaner is upstream of and adjacent to the second cleaner in a moving direction of the toner image bearer, and
wherein the circuitry is further configured to
set a first untransferred toner correction coefficient for the first cleaner, the first untransferred toner correction coefficient increasing an absolute value of the first bias applied to the first cleaner to be larger than an absolute value of the third bias applied to the first cleaner; and
set a second untransferred toner correction coefficient for the second cleaner that decreases an absolute value of the second bias applied to the second cleaner to be smaller than an absolute value of a fourth bias applied to the second cleaner.

6. The image forming apparatus according to claim 1 , wherein the multiple cleaners include at least one of cleaning brushes or cleaning rollers.

7. An image forming apparatus comprising:
a toner image bearer configured to bear a toner image formed by an image forming operation;
a transfer device configured to perform a transfer process to transfer the toner image from the toner image bearer to a sheet;
a cleaner contacting the toner image bearer, the cleaner configured to
remove transfer residual toner on the toner image bearer that is subject to the transfer process, and
remove untransferred toner on the toner image bearer that is not subject to the transfer process;

a bias power source configured to apply one of a first bias or a second bias different from the first bias to the cleaner;
a motor rotatable at different linear velocities to drive the toner image bearer and the cleaner; and
circuitry configured to
control the bias power source to output the first bias to the cleaner in response to a start of the image forming operation to remove the untransferred toner from the toner image bearer,
control the bias power source to switch an output from the first bias to the second bias to remove the transfer residual toner from the toner image bearer, and
change the bias based on the different linear velocities of the motor.

8. The image forming apparatus according to claim 7 , further comprising:
multiple cleaners including the cleaner, the multiple cleaners contacting the toner image bearer and having different resistance values with each other; and
multiple bias power sources including the bias power source,
wherein the multiple bias power sources are configured to apply one of the first bias or the second bias to the multiple cleaners, respectively,
wherein the circuitry is further configured to determine the first bias and the second bias to be output to the multiple cleaners differently according to the resistance values of the multiple cleaners.

9. The image forming apparatus according to claim 8 ,
wherein the multiple cleaners include:
a first cleaner having a first resistance, and
a second cleaner having a second resistance greater than the first resistance, and

wherein the multiple bias power sources include
a first bias power source configured to apply a first bias to the first cleaner; and

a second bias power source configured to apply a second bias, larger than the first bias, to the second cleaner.

10. The image forming apparatus according to claim 7 , further comprising:
a sensor configure

Assignees

• Goto Yutaka
• Kogure Seiichi
• Kikuchi Hiroshi
• Hatta Hirotaka
• Kimura Hideki
• Ishizuka Yusuke
• Akiyama Takuya
• Aoki Yuuki
• Ricoh Co Ltd

Inventors

• Goto Yutaka
• Kogure Seiichi
• Kikuchi Hiroshi
• Hatta Hirotaka
• Kimura Hideki
• Ishizuka Yusuke
• Akiyama Takuya
• Aoki Yuuki

Classifications

• G03G15/161

  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

• G03G2221/1627

  Details concerning the cleaning process · CPC title

• G03G21/0076 Primary

  Plural or sequential cleaning devices · CPC title

• G03G21/0047 Primary

  using electrostatic or magnetic means; Details thereof, e.g. magnetic pole arrangement of magnetic devices (G03G21/0064 takes precedence) · CPC title