Fuser including endless belt and lateral guide contacting lateral end of endless belt

Patent metadata

Field	Value
Publication number	US-10488797-B2
Application number	US-201815933488-A
Country	US
Kind code	B2
Filing date	Mar 23, 2018
Priority date	Mar 28, 2017
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

There is provided a fuser including: a cylindrical member; an endless belt; a pressing member; a pressing roller; and a lateral guide contacting a lateral end of the endless belt. A part of an outer circumferential surface of the pressing roller is located on a downstream of the second nip area in a first direction. A guide surface of the lateral guide has: a first guide surface located on an opposite side to the pressing roller with respect to a virtual plane including the center of a first nip area and the center of rotation of the cylindrical member, and a second guide surface located on a side of the pressing roller with respect to the virtual plane, located on the downstream side of the rotation axis of the pressing roller in the first direction, and arranged on a same plane as the first guide surface.

First claim

What is claimed is:

1. A fuser comprising:
a cylindrical member;
an endless belt including an outer circumferential surface contacting the cylindrical member, an inner circumferential surface being a reverse surface of the outer circumferential surface, and a lateral edge being an edge of the endless belt in a width direction of the endless belt;
a pressing member contacting the inner circumferential surface of the endless belt and sandwiching the endless belt together with the cylindrical member so as to form a first nip area;
a pressing roller contacting the inner circumferential surface of the endless belt and sandwiching the endless belt together with the cylindrical member so as to form a second nip area; and
a lateral guide including a guide surface contacting the lateral edge of the endless belt,
wherein a part of an outer circumferential surface of the pressing roller is located downstream of the second nip area in a first direction, the first direction being perpendicular to a rotation axis of the pressing roller and directing from a center of the first nip area toward a center of rotation of the cylindrical member,
wherein the guide surface includes a first guide surface and a second guide surface,
the first guide surface being located such that the pressing member is located between the pressing roller and the first guide surface in a predetermined direction, the predetermined direction being perpendicular to the rotational axis and the first direction, and
the second guide surface being located such that the pressing member is located between the second guide surface and the first guide surface in the predetermined direction, the second guide surface being located downstream of the rotation axis of the pressing roller in the first direction, the second guide surface contacting a downstream portion of the lateral edge of the endless belt, the downstream portion of the lateral edge being located downstream of the second nip area in the first direction, and the second guide surface being arranged on a same plane as the first guide surface, and

wherein the lateral guide defines a gap between the first guide surface and the second guide surface in the predetermined direction, and portions of the endless belt at the first and second nip areas are located within the gap in the predetermined direction such that the lateral edge of the portions of the endless belt do not contact both the first guide surface and the second guide surface.

2. The fuser according to claim 1 , wherein the guide surface includes a third guide surface connecting the first guide surface and the second guide surface, the third guide surface being arranged on the same plane as the first and second guide surfaces.

3. The fuser according to claim 1 , wherein the pressing roller includes: a roller portion contacting the inner circumferential surface of the endless belt, and a shaft projecting from an end of the roller portion,
wherein the fuser further comprises a supporting member supporting the shaft of the pressing roller and the pressing member, and
wherein the guide surface is arranged between the supporting member and the roller portion in an axial direction parallel to the rotation axis of the pressing roller.

4. The fuser according to claim 3 , wherein the lateral guide includes:
a first circular-arc surface along an outer circumferential surface of the shaft; and
a second circular-arc surface along an outer circumferential surface of the roller portion, and
wherein in a radial direction of the pressing roller, a distance from the first circular-arc surface to the second circular-arc surface is smaller than a distance from the outer circumferential surface of the shaft to the outer circumferential surface of the roller portion.

5. The fuser according to claim 4 , further comprising a bearing provided on the supporting member and supporting the shaft,
wherein the bearing projects toward the roller portion from a surface, of the supporting member, facing the roller portion; and
a radius of the first circular-arc surface is smaller than a radius of an outer circumferential surface of the bearing.

6. The fuser according to claim 5 , wherein the lateral guide includes a projection projecting toward the supporting member, and
in a second direction along the rotation axis, a distance from a surface, of the bearing, facing the lateral guide to a surface, of the lateral guide, facing the bearing is equal to a distance from a surface, of the projection, facing the supporting member to a surface, of the supporting member, facing the lateral guide.

7. The fuser according to claim 6 , wherein the center of the first nip area is located between the bearing and at least a part of the projection in the predetermined direction.

8. The fuser according to claim 1 , further comprising a stay supporting the pressing member at an inner space formed by the endless belt,
wherein the lateral guide contacts an outer surface of the stay.

9. The fuser according to claim 8 , wherein the stay has a U-shaped cross section, and wherein the lateral guide includes an engaging part engaging an inner surface of the stay.

10. The fuser according to claim 8 , wherein the lateral guide is movable, with respect to the stay, in a second direction along the rotation axis of the pressing roller.

11. The fuser according to claim 1 , wherein the lateral guide is supported by the endless belt.

12. The fuser according to claim 1 , wherein the lateral guide includes an inner circumferential guide surface contacting the inner circumferential surface of the endless belt.

13. The fuser according to claim 1 , wherein the pressing member includes a pad.

14. The fuser according to claim 13 , wherein the pad is formed of rubber.

15. The fuser according to claim 1 , wherein the pressing roller is disposed at a downstream side of the pressing member in a movement direction of the endless belt at the first nip area.

16. The fuser according to claim 1 , wherein the cylindrical member includes a tube and a heater disposed in the tube.

Assignees

• Brother Ind Ltd

Inventors

• Fujii Yasumasa
• Tanaka Tokifumi
• Kuriki Hirofumi
• Kajita Masahito
• Takeuchi Kenji
• Handa Hiroshi

Classifications

• G03G15/2053

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

• G03G2215/2009

  Pressure belt · CPC title

• G03G15/2064 Primary

  combined with pressure · CPC title

• G03G2215/2022

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

• G03G15/2032

  Retractable heating or pressure unit · CPC title