Fixing device and image forming apparatus

Patent metadata

Field	Value
Publication number	US-12393141-B2
Application number	US-202318180509-A
Country	US
Kind code	B2
Filing date	Mar 8, 2023
Priority date	Mar 18, 2022
Publication date	Aug 19, 2025
Grant date	Aug 19, 2025

Abstract

A fixing device includes a rotator, a heater, a rotator support, a nip formation pad, lubricant, and a pressure rotator. The heater heats an inner circumferential surface of the rotator. The rotator support supports an end of the inner circumferential surface of the rotator in an axial direction of the rotator. The rotator slides on the rotator support. The nip formation pad is in contact with the inner circumferential surface of the rotator. One end of the nip formation pad in a longitudinal direction of the nip formation pad is separated from the rotator support with a clearance of 2 mm or more. The lubricant is between the rotator and the nip formation pad. The pressure rotator presses the nip formation pad via the rotator to form a nip between the rotator and the pressure rotator.

First claim

What is claimed is:

1. A fixing device comprising:
a rotator configured to rotate;
a heater configured to heat an inner circumferential surface of the rotator;
a rotator support including a base portion and a cylindrical wall extending from the base portion, the cylindrical wall supporting a first end of the inner circumferential surface of the rotator extending from a nip in a longitudinal direction of a nip formation pad, and supporting a second end of the inner circumferential surface of the rotator facing the first end, the base portion defining a base opening, and the cylindrical wall defining an extension opening;
the nip formation pad in contact with the inner circumferential surface of the rotator, the nip formation pad having one end in a longitudinal direction of the nip formation pad, the one end laterally separated from the first end of the rotator support contacting the inner circumferential surface of the rotator with a clearance of 2 mm or more;
lubricant between the rotator and the nip formation pad;
a pressure rotator configured to press the nip formation pad via the rotator to form a nip between the rotator and the pressure rotator; and
a flower preventer in contact with the inner circumferential surface of the rotator at a same level as the cylindrical wall contacting the inner circumferential surface of the rotator, the flower preventer separated from and between the nip formation pad and the rotator support that form the clearance forming a lubricant gap exposing the inner circumferential surface of the rotator between the flower preventer and the nip formation pad,
the cylindrical wall having a side surface facing the nip formation pad.

2. The fixing device according to claim 1 ,
wherein the flow preventer has an O-shape in an axial direction along the inner circumferential surface of the rotator.

3. The fixing device according to claim 1 , further comprising
a lubricant absorber in contact with the inner circumferential surface of the rotator between the nip formation pad and the rotator support that form the clearance, the lubricant absorber om the nip formation pad.

4. The fixing device according to claim 1 , further comprising
a sliding sheet impregnated with lubricant and disposed between the nip formation pad and the rotator.

5. The fixing device according to claim 1 ,
wherein the nip formation pad has a space between the rotator and the nip formation pad to store lubricant.

6. The fixing device according to claim 5 , wherein
the nip formation pad includes a groove,
the groove and the rotator cooperatively define the space, and
the space is a closed space configured to prevent lubricant from moving outside of the nip formation pad in an axial direction.

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

8. The fixing device according to claim 1 ,
wherein the rotator support includes a portion having an outer circumference equal to an inner circumference of the inner circumferential surface of the rotator.

Assignees

• Shiodera Kota
• Andoh Takayuki
• Samei Masahiro
• Kabata Toshiyuki
• Yoshinaga Hiroshi
• Ricoh Co Ltd

Inventors

• Shiodera Kota
• Andoh Takayuki
• Samei Masahiro
• Kabata Toshiyuki
• Yoshinaga Hiroshi

Classifications

• G03G15/2025 Primary

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

• G03G2215/2035

  the fixing nip having a stationary belt support member opposing a pressure member · CPC title

• G03G15/2053 Primary

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