Fixing device and image forming apparatus incorporating the same

Patent metadata

Field	Value
Publication number	US-12092978-B2
Application number	US-202318329201-A
Country	US
Kind code	B2
Filing date	Jun 5, 2023
Priority date	Jun 16, 2022
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

A fixing device includes a first rotator, a second rotator, a heater, a nip formation pad, and a separator. The second rotator contacts an outer circumferential surface of the first rotator to form a nip between the first rotator and the second rotator. The heater includes a resistive heat generator to heat the first rotator. The nip formation pad contacts an inner circumferential surface of the first rotator to form the nip. The separator separates a recording medium passing through the nip from the first rotator. The separator includes a separating surface and a contact. The separating surface is separated from the outer circumferential surface of the first rotator and separates the recording medium from the first rotator. The contact contacts the outer circumferential surface of the first rotator at a position where the first rotator is pinchable between the contact and the nip formation pad.

First claim

The invention claimed is:

1. A fixing device comprising:
a first rotator;
a second rotator contacting an outer circumferential surface of the first rotator to form a nip between the first rotator and the second rotator;
a heater including a resistive heat generator configured to heat the first rotator;
a nip formation pad contacting an inner circumferential surface of the first rotator to form the nip; and
a separator configured to separate a recording medium passing through the nip from the first rotator, the separator including:
a separating surface separated from the outer circumferential surface of the first rotator and configured to separate the recording medium from the first rotator; and
a contact contacting the outer circumferential surface of the first rotator at a position where the first rotator is pinchable between the contact and the nip information pad.

2. The fixing device according to claim 1 ,
wherein the contact contacts a non-passing region of the outer circumferential surface of the first rotator, and the non-passing region is outside a maximum recording medium passing region through which the recording medium having the maximum width passes.

3. The fixing device according to claim 1 ,
wherein the nip information pad holds the heater contacting the inner circumferential surface of the first rotator opposing the nip.

4. The fixing device according to claim 3 ,
wherein the heater has a flat surface contacting the inner circumferential surface of the first rotator.

5. The fixing device according to claim 3 ,
wherein the heater has a contacting surface contacting the first rotator,
the nip formation pad has a projection projected from the contacting surface of the heater toward the second rotator, and
the projection is downstream from a center of the nip in a medium passing direction in which the recording medium passes through the nip.

6. The fixing device according to claim 1 ,
wherein the nip formation pad has:
multiple guides; and
a contact surface contacting the inner circumferential surface of the first rotator opposing the nip,

the contact surface extends longer than one of the multiple guides in a longitudinal direction of the first rotator.

7. The fixing device according to claim 1 ,
wherein the contact contacts an outer region of the outer circumferential surface of the first rotator, and
the outer region is outside the resistive heat generator in a longitudinal direction of the first rotator.

8. The fixing device according to claim 1 ,
wherein the second rotator rotates the first rotator.

9. The fixing device according to claim 1 ,
wherein the first rotator includes a base layer made of resin.

10. The fixing device according to claim 1 , further comprising:
a pressing member configured to bring the first rotator and the second rotator into pressure contact with each other; and
a pressure release mechanism configured to release the pressure contact between the first rotator and the second rotator.

11. The fixing device according to claim 1 ,
wherein the contact is made of an elastic material.

12. The fixing device according to claim 1 ,
wherein an outer diameter of the first rotator is larger than an outer diameter of the second rotator.

13. The fixing device according to claim 1 , further comprising
a pressing member configured to press the second rotator against the first rotator.

14. The fixing device according to claim 1 ,
wherein the plate has a leading end, and
the leading end has:
a first clearance between the outer circumferential surface of the first rotator and the leading end of the plate at a center of the first rotator in a longitudinal direction of the first rotator; and
a second clearance between the outer circumferential surface of the first rotator and the leading end of the plate at both ends of the first rotator in the longitudinal direction, the second clearance being smaller than the first clearance.

15. The fixing device according to claim 1 ,
wherein the first rotator includes:
a base layer; and
a surface layer on an outer circumferential surface of the base layer.

16. The fixing device according to claim 1 ,
wherein the heater includes multiple resistive heat generators including the resistive heat generator, and
the multiple resistive heat generators are arranged in a longitudinal direction of the first rotator.

17. An image forming apparatus comprising the fixing device according to claim 1 .

Assignees

• Someya Yukimichi
• Furuichi Yuusuke
• Adachi Tomoya
• Shimada Hiroyuki
• Ricoh Co Ltd

Inventors

• Someya Yukimichi
• Furuichi Yuusuke
• Adachi Tomoya
• Shimada Hiroyuki

Classifications

• G03G15/2028 Primary

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

• G03G15/2053 Primary

  Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating · CPC title