Fixing device including a cleaner to clean a surface of a cleaning target and image forming apparatus incorporating same

Patent metadata

Field	Value
Publication number	US-10852671-B2
Application number	US-201916675912-A
Country	US
Kind code	B2
Filing date	Nov 6, 2019
Priority date	Nov 15, 2018
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A fixing device includes a fixing rotator, a pressure rotator, a cleaner, and a moving assembly. The cleaner contacts and cleans a cleaning target, which includes one of the fixing rotator and the pressure rotator. The moving assembly moves the cleaner between a contact position at which the cleaner contacts the cleaning target and a separate position at which the cleaner is apart from the cleaning target. The moving assembly includes a biasing member that presses the cleaner to move to the contact position. The moving assembly moves the cleaner from the contact position to the separate position against a biasing force of the biasing member. The moving assembly moves the cleaner from the separate position to the contact position while increasing and then decreasing the biasing force of the biasing member greater than the biasing force applied when the cleaner is located at the contact position.

First claim

What is claimed is:

1. A fixing device comprising:
a fixing rotator configured to heat a toner image and fix the toner image onto a surface of a recording medium;
a pressure rotator configured to press against the fixing rotator to form a fixing nip through which the recording medium is conveyed between the fixing rotator and the pressure rotator;
a cleaner configured to contact and clean a surface of a cleaning target, the cleaning target including one of the fixing rotator and the pressure rotator; and
a moving assembly configured to move the cleaner between a contact position at which the cleaner contacts the surface of the cleaning target and a separate position at which the cleaner is apart from the surface of the cleaning target, the moving assembly including,
a biasing member configured to press the cleaner to move to the contact position,
a cam follower, and
an eccentric cam including a cam face configured to contact the cam follower as the eccentric cam rotates to move the cleaner from the contact position to the separate position against a biasing force of the biasing member while first to third portions of the cam face sequentially approach the cam follower as the cleaner moves from the contact position to the separate position, a radius of the second portion of the cam face being largest amongst the first to third portions such that the biasing force of the biasing member increases and then decreases as the cleaner moves from the contact position to the separate position.

2. The fixing device according to claim 1 , wherein the moving assembly further includes: a cam shaft, the eccentric cam rotatable about the cam shaft, a pivot and an arm rotatable about the pivot, the arm configured to hold the cleaner, and to contact the eccentric cam,
wherein the second portion of the cam face is a maximum radius portion and the third portion of the cam face is a large radius portion,
wherein the large radius portion is in a range of 60 degrees or greater around the cam shaft, to locate the cleaner at the separate position,
wherein the maximum radius portion is adjacent to the large radius portion and having a larger radius than the large radius portion; and
wherein the biasing member is configured to press and rotate the arm to move the cleaner to the contact position.

3. The fixing device according to claim 1 ,
wherein the moving assembly further includes a cam shaft, the eccentric cam rotatable about the cam shaft, a pivot, an arm rotatable about the pivot, and a driven gear rotatable together with the cam shaft, the arm configured to hold the cleaner, and to contact the eccentric cam,
wherein the biasing member is configured to press and rotate the arm to move the cleaner to the contact position,
wherein the moving assembly is configured to move the cleaner from the contact position to the separate position before the fixing device is removed from an image forming apparatus, and
wherein the cleaner is configured to remain at the separate position when the driven gear meshing with a driving gear of the image forming apparatus rotates and comes apart from the driving gear in conjunction with removal of the fixing device from the image forming apparatus.

4. The fixing device according to claim 3 ,
wherein the biasing member includes a torsion spring that includes an arm portion on a longitudinal end side of the torsion spring,
wherein the arm portion is configured to be hooked on the arm, and
wherein the arm includes the cam follower that is configured to contact the eccentric cam.

5. The fixing device according to claim 1 ,
wherein the moving assembly further includes a cam shaft, the eccentric cam rotatable about the cam shaft, a pivot, and an arm rotatable about the pivot, the arm configured to hold the cleaner, and to contact the eccentric cam,
wherein the biasing member is configured to press and rotate the arm to move the cleaner to the contact position,
wherein the pivot is located between a contact part at which the arm contacts the eccentric cam and a point of effort at which the biasing member presses the arm, and
wherein a relation of A/B≤1.5 is satisfied, where A represents a distance between the contact part and the pivot and B represents a distance between the point of effort and the pivot.

6. The fixing device according to claim 1 , further comprising:
a temperature detector configured to detect a temperature of one of the cleaner and the cleaning target,
wherein the moving assembly is configured to move the cleaner from the contact position to the separate position or from the separate position to the contact position during rotation of the cleaning target, in a case in which the temperature detected by the temperature detector is greater than a given value, and
wherein the moving assembly is configured to move the cleaner from the contact position to the separate position or from the separate position to the contact position during a stop of rotation of the cleaning target, in a case in which the temperature detected by the temperature detector is equal to or smaller than the given value.

7. The fixing device according to claim 1 , wherein the cleaner includes a cleaning roller that is configured to rotate together with the cleaning target when the cleaner is in contact with the cleaning target rotating in a given direction.

8. An image forming apparatus comprising:
an image bearer configured to bear a toner image; and
the fixing device according to claim 1 , the fixing device being configured to fix the toner image onto the surface of the recording medium.

9. A fixing device comprising:
a fixing rotator configured to heat a toner image and fix the toner image onto a surface of a recording medium;
a pressure rotator configured to press against the fixing rotator to form a fixing nip through which the recording medium is conveyed between the fixing rotator and the pressure rotator;
a cleaner configured to contact and clean a surface of a cleaning target, the cleaning target including one of the fixing rotator and the pressure rotator; and
a moving assembly configured to move the cleaner between a contact position at which the cleaner contacts the surface of the cleaning target and a separate position at which the cleaner is apart from the surface of the cleaning target, the moving assembly including,
a biasing member configured to press the cleaner to move to the contact position,
a cam follower, and
an eccentric cam including a cam face configured to contact the cam follower as the eccentric cam rotates to move the cleaner from the contact position to the separate position against a biasing force of the biasing member while first to third portions of the cam face sequentially approach the cam follower as the cleaner moves from the contact position to the separate position, a radius of the second portion of the cam face being largest amongst the first to third portions such that the biasing force of the biasing member increases and then is maintained at a force greater than the biasing force applied when the cleaner is located at the contact position and then decreases as the cleaner moves from the contact position to the separate position.

10. The fixing device according to claim 9 , wherein the moving assembly further includes: a cam shaft, the eccentric cam rotatable about the cam shaft, a pivot and an arm rotatable about the pivot, the arm configured to hold the cleaner and to contact the eccentric cam,
wherein the biasing member is configured to press and rotate the arm to move the cleaner to the contact position, and
wherein the third portion of the cam face is a large radius portion in a range of 60 degrees or greater around the cam shaft, to loca

Assignees

• Imada Takahiro
• Hattori Yoshio
• Sasaki Yoshikuni
• Yamaoka Hironori
• Ishigaya Yasunori
• Waida Takumi
• Ricoh Co Ltd

Inventors

• Imada Takahiro
• Hattori Yoshio
• Sasaki Yoshikuni
• Yamaoka Hironori
• Ishigaya Yasunori
• Waida Takumi

Classifications

• G03G15/2025 Primary

  with special means for lubricating and/or cleaning the fixing unit, e.g. applying offset preventing fluid · CPC title