Image forming apparatus that controls the speed difference between a transfer belt and a conveying unit or a fixing unit

Patent metadata

Field	Value
Publication number	US-11274003-B2
Application number	US-201916582189-A
Country	US
Kind code	B2
Filing date	Sep 25, 2019
Priority date	Sep 28, 2018
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

An image forming apparatus includes: a belt unit including a transfer belt and a first memory that stores a first sheet conveying speed of the transfer belt; a second memory storing a first reference value and a second sheet conveying speed of the fixing unit a controller configured to: control at least one of the belt motor and the fixing motor to bring the speed difference between the sheet conveying speed of the transfer belt and the sheet conveying speed of the fixing unit closer to the first reference value by setting a rotational speed of the fixing motor based on the first reference value and a first speed difference between the first sheet conveying speed read from the first memory and the second sheet conveying speed read from the second memory.

First claim

What is claimed is:

1. An image forming apparatus comprising:
an apparatus main body;
a photosensitive drum;
a belt unit that is detachably attachable to the apparatus main body, the belt unit including a transfer belt and a first memory, the transfer belt being configured to convey the sheet and to transfer a toner image on the photosensitive drum onto the sheet, the first memory storing a first sheet conveying speed which is an original sheet conveying speed of the transfer belt;
a fixing unit that includes a fixing roller that heats the sheet and a pressure roller that presses the fixing roller, the fixing unit configured to fix the toner image on the sheet conveyed by the transfer belt to the sheet in a state where the belt unit is attached to the apparatus main body;
a belt motor configured to drive the transfer belt;
a fixing motor configured to drive the fixing unit;
a second memory storing a second sheet conveying speed and a first reference value, wherein the second sheet conveying speed is an original sheet conveying speed of the fixing unit, and wherein the first reference value is a reference value of a speed difference between an actual sheet conveying speed of the transfer belt and an actual sheet conveying speed of the fixing unit; and
a controller configured to:
read the first sheet conveying speed from the first memory;
read the second sheet conveying speed from the second memory; and
control at least one of the belt motor and the fixing motor to bring the speed difference between the actual sheet conveying speed of the transfer belt and the actual sheet conveying speed of the fixing unit closer to the first reference value by setting at least one of a rotational speed of the belt motor and a rotational speed of the fixing motor based on the first reference value and a first speed difference which is a speed difference between the first sheet conveying speed read from the first memory and the second sheet conveying speed read from the second memory.

2. The image forming apparatus according to claim 1 ,
wherein the first sheet conveying speed, which is stored in the first memory, is the original sheet conveying speed of the transfer belt that is obtained based on a value measured in advance.

3. The image forming apparatus according to claim 1 ,
wherein the second sheet conveying speed, which is stored in the second memory, is the original sheet conveying speed of the fixing unit that is obtained based on a value measured in advance.

4. The image forming apparatus according to claim 1 ,
wherein the belt motor is configured to drive the photosensitive drum.

5. The image forming apparatus according to claim 1 ,
wherein, in controlling at least one of the belt motor and the fixing motor, the controller sets the rotational speed of the fixing motor based on the first speed difference and the first reference value.

6. The image forming apparatus according to claim 5 ,
wherein, in controlling at least one of the belt motor and the fixing motor, the controller decreases the rotational speed of the fixing motor in a case where the first speed difference is greater than the first reference value and increases the rotational speed of the fixing motor in a case where the first speed difference is smaller than the first reference value.

7. The image forming apparatus according to claim 1 ,
wherein the transfer belt conveys the sheet between the transfer belt and the photosensitive drum.

8. The image forming apparatus according to claim 1 ,
wherein the transfer belt is an endless belt.

9. The image forming apparatus according to claim 1 ,
wherein the first sheet conveying speed is an actual measurement value of the original sheet conveying speed of the transfer belt measured in advance.

10. The image forming apparatus according to claim 1 ,
wherein the belt unit includes a belt drive roller and a belt driven roller, wherein the belt drive roller is configured to drive the transfer belt and is in contact with an inner circumferential surface of the transfer belt, wherein the belt driven roller is configured to be rotated by being driven by the transfer belt and is positioned at a position apart from the belt drive roller, and wherein the belt driven roller is in contact with the inner circumferential surface of the transfer belt, and
wherein the first sheet conveying speed is a calculation value calculated based on a thickness of the transfer belt measured in advance and a value of an outer diameter of the belt drive roller.

11. The image forming apparatus according to claim 1 ,
wherein the first sheet conveying speed stored in the first memory is faster than the second sheet conveying speed stored in the second memory.

12. The image forming apparatus according to claim 1 ,
wherein the second sheet conveying speed is an actual measurement value of the original sheet conveying speed of the fixing unit measured in advance.

13. The image forming apparatus according to claim 1 ,
wherein the fixing unit includes a fixing roller that is configured to heat the sheet, and
wherein the second sheet conveying speed is a calculation value calculated based on a value of an outer diameter of the fixing roller measured in advance.

14. The image forming apparatus according to claim 1 ,
wherein the apparatus main body includes a cover that is configured to take an opened state and a closed state, wherein the cover allows the belt unit to be attached to and detached from the apparatus main body in the opened state,
wherein the image forming apparatus further comprises:
a first sensor configured to detect the opened state and the closed state of the cover; and
a second sensor that detects whether or not the belt unit is attached to the apparatus main body,
wherein the controller starts reading the first sheet conveying speed and the second sheet conveying speed in a state where the first sensor detects the cover being at the closed state and the second sensor detects the belt unit being attached to the apparatus main body.

15. The image forming apparatus according to claim 1 ,
wherein the second memory is configured to store a reference sheet conveying speed which is a reference value of the sheet conveying speed of the transfer belt, and
wherein the controller is configured to:
in reading the first sheet conveying speed and the second sheet conveying speed, read the reference sheet conveying speed from the second memory in a case where the first sheet conveying speed is not able to be read out from the first memory; and
in controlling at least one of the belt motor and the fixing motor, set a speed difference between the reference sheet conveying speed read from the second memory and the second sheet conveying speed read from the second memory as the first speed difference.

16. The image forming apparatus according to claim 1 ,
wherein the second memory is configured to store a reference sheet conveying speed which is a reference value of the actual sheet conveying speed of the transfer belt, and
wherein the controller is configured to:
in reading the first sheet conveying speed and the second sheet conveying speed, read the reference sheet conveying speed from the second memory; and
in controlling at least one of the belt motor and the fixing motor, set a speed difference between the reference sheet conveying speed read from the second memory and the second sheet conveying speed read from the second memory as the first speed difference in a case where the speed difference between the first sheet conveying speed read from the first memory and the referen

Assignees

• Brother Ind Ltd

Inventors

• Hashimoto Junichi
• Inoue Masafumi
• Ota Shuji
• Hatano Shuhei

Classifications

• G03G2215/00603

  Control of other part of the apparatus according to the state of copy medium feeding · CPC title

• G03G15/6555

  Handling of sheet copy material taking place in a specific part of the copy material feeding path · CPC title

• G03G15/5008 Primary

  Driving control for rotary photosensitive medium, e.g. speed control, stop position control · CPC title

• G03G15/20

  for fixing, e.g. by using heat · CPC title

• B65H5/021 Primary

  by belts · CPC title