Image forming apparatus to prevent air duct bending

Patent metadata

Field	Value
Publication number	US-12386309-B2
Application number	US-202418648163-A
Country	US
Kind code	B2
Filing date	Apr 26, 2024
Priority date	Feb 7, 2022
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

An image forming apparatus includes a photosensitive member, a transfer unit having a transfer belt, a primary transfer roller, a secondary transfer inner roller below the primary transfer roller in a vertical direction, and a stretching roller, a secondary transfer outer roller, a support unit, and an air duct provided in the transfer unit. The secondary transfer outer roller faces the secondary transfer inner roller via the transfer belt and forms a nip portion for secondarily transferring a toner image on the transfer belt to a sheet. The air duct is located downstream of the nip portion in a sheet conveyance direction and below a portion of the transfer belt stretched between the secondary transfer inner roller and the stretching roller in the vertical direction. The air duct includes an air intake port and moves with the transfer unit with movement of the transfer unit from the support unit.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a photosensitive member;
a transfer unit including:
a transfer belt onto which a toner image formed on a photosensitive member is transferred;
a primary transfer roller that faces the photosensitive member via the transfer belt and forms a primary transfer nip portion for primarily transferring the toner image formed on the photosensitive member to the transfer belt;
a secondary transfer inner roller that is provided below the primary transfer roller in a vertical direction and in contact with an inner circumferential surface of the transfer belt; and
a stretching roller for stretching the transfer belt that is provided between the secondary transfer inner roller and the primary transfer roller in a rotation direction of the transfer belt;
a secondary transfer outer roller configured to face the secondary transfer inner roller via the transfer belt and to form a secondary transfer nip portion for secondarily transferring the toner image formed on the transfer belt to a recording material;
a support unit configured to support the transfer unit to move along a rotation axis direction of the secondary transfer inner roller;
an air duct which includes a joint portion with a second duct and is provided in the transfer unit and is configured to move integrally with the transfer unit along with movement of the transfer unit from the support unit; and
a sealing member provided between the joint portion of the air duct and the second duct to seal the joint portion of the air duct.

2. The image forming apparatus according to claim 1 , wherein the transfer unit further includes a cleaning unit that is provided downstream of the secondary transfer nip portion in the rotation direction of the transfer belt and is configured to clean an outer circumferential surface of the transfer belt.

3. The image forming apparatus according to claim 2 , wherein the air duct is fixed to the cleaning unit.

4. The image forming apparatus according to claim 2 , further comprising a guide unit that is provided between the secondary transfer nip portion and the cleaning unit in a conveyance direction of the recording material and is configured to prevent a sheet from sticking to the transfer belt,
wherein the air duct is provided integrally with the guide unit.

5. The image forming apparatus according to claim 1 , further comprising:
a conveyance unit,
wherein the conveyance unit includes a conveyance roller that is located downstream of the secondary transfer nip portion in a conveyance direction and is configured to convey the recording material onto which the toner image is transferred at the secondary transfer nip portion,
wherein the conveyance unit is supported by the support unit to be movable along a rotation axis direction of the secondary transfer outer roller.

6. The image forming apparatus according to claim 5 , wherein the air duct is provided between a portion of the transfer belt stretched between the secondary transfer inner roller and the stretching roller and the conveyance roller in the vertical direction.

7. The image forming apparatus according to claim 6 , wherein the air intake port is provided outside an end portion of the transfer belt in the rotation axis direction of the secondary transfer inner roller.

8. The image forming apparatus according to claim 5 , further comprising a fixing unit that is provided in the conveyance unit and is configured to fix the toner image to the recording material conveyed by the conveyance roller,
wherein the air duct is provided between a portion of the transfer belt stretched between the secondary transfer inner roller and the stretching roller and the fixing unit in the vertical direction.

9. The image forming apparatus according to claim 8 ,
wherein the fixing unit includes a heating unit, a first rotating member to be heated by the heating unit, and a second rotating member that forms a fixing nip together with the first rotating member, and
wherein the air intake port is provided upstream of the fixing nip in the conveyance direction of the recording material.

10. The image forming apparatus according to claim 9 , wherein the air duct includes another air intake port provided downstream of the fixing nip in the conveyance direction of the recording material.

11. The image forming apparatus according to claim 8 ,
wherein the transfer unit is configured to move between a mounting position where the secondary transfer nip portion is formed by the secondary transfer inner roller and the secondary transfer outer roller and a pull-out position where the transfer unit is moved from the mounting position and pulled out forward from the image forming apparatus,
wherein the transfer unit includes an operating lever configured to be rotated in a state in which the transfer unit is located at the mounting position to move the transfer belt in a direction away from the photosensitive member, and
wherein the transfer unit is configured to move to the pull-out position in a state in which the operating lever is rotated.

12. The image forming apparatus according to claim 11 , wherein the air duct includes an exhaust port configured to exhaust air taken from the air intake port, the image forming apparatus further comprising a duct unit,
wherein the duct unit includes another air intake port configured to be joined to the exhaust port in the state in which the transfer unit is located at the mounting position and to be separated from the exhaust port in a state in which the transfer unit is located at the pull-out position and includes a fan configured to form an airflow inside the air duct in the state in which the transfer unit is located at the mounting position.

13. The image forming apparatus according to claim 12 , further comprising:
a first housing configured to include the photosensitive member, the transfer unit, and the conveyance roller; and
a second housing configured to include the fixing unit, wherein the air duct is provided between the transfer belt and the fixing unit in the conveyance direction of the recording material, wherein the air duct includes another air intake port different from the air intake port, and wherein the image forming apparatus further comprises another duct unit that includes another exhaust port configured to be joined to the another air intake port in a state in which the transfer unit is located at the mounting position and to be separated from the another air intake port in a state in which the transfer unit is located at the pull-out position.

14. The image forming apparatus according to claim 12 , further comprising:
a first housing configured to include the photosensitive member, the transfer unit, and the conveyance roller; and
a second housing configured to include the fixing unit, wherein the air duct is provided between the transfer belt and the fixing unit in the conveyance direction of the recording material in the secondary transfer nip portion, wherein the air duct includes another air intake port different from the air intake port, and wherein the image forming apparatus further comprises another
duct unit that includes another exhaust port configured to be joined to the another air intake port in a state in which the transfer unit is located at the mounting position and to be separated from the another air intake port in a state in which the transfer unit is located at the pull-out position.

15. The image forming apparatus according to claim 12 , wherein the air duct is located downstream of the secondary transfer nip portion in a conveyance direction of

Assignees

• Canon Kk

Inventors

• Fujita Keiko
• Yamana Kentaro
• Doi Shigeo
• Yokobori Yuya
• Nojima Hiroshi

Classifications

• G03G15/2028

  with means for handling the copy material in the fixing nip, e.g. introduction guides, stripping means · CPC title

• G03G2215/1661

  of transfer belt · CPC title

• G03G2215/0132

  vertical medium transport path at the secondary transfer · CPC title

• G03G2221/1642

  for the transfer unit · CPC title

• G03G15/161

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