Fixing device and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9400465-B2
Application number	US-201514933246-A
Country	US
Kind code	B2
Filing date	Nov 5, 2015
Priority date	Nov 10, 2014
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

A fixing device fixing an image on a recording medium includes a fixing belt rotatable around a first rotation axis, a pressuring member, a heat source body and a cover member. The pressuring member forms a nip part pressuring and making the recording medium pass through with the fixing belt. The heat source body is arranged inside the fixing belt and heats the fixing belt by emitting radiant heat. The cover member is arranged between the fixing belt and the heat source body and covers the heat source body. The nip part has a passing area where the recording medium passes through and a non-passing area outside the passing area in an axial direction. The cover member covers a part of the heat source body corresponding to the non-passing area and includes through holes formed so as to adjust surface temperature of the heat source body.

First claim

What is claimed is:

1. A fixing device fixing an image on a recording medium comprising:
an endless fixing belt rotatably arranged around a first rotation axis;
a pressuring member rotatably arranged around a second rotation axis in parallel to the first rotation axis and configured so as to form a nip part pressuring and making the recording medium pass through with the fixing belt;
a heat source body arranged inside the fixing belt and configured so as to have a longitudinal shape extending in roughly parallel to the first rotation axis and to heat the fixing belt by emitting radiant heat; and
a cover member arranged between the fixing belt and the heat source body and configured so as to cover the heat source body,
wherein the nip part has a passing area as an area where the recording medium passes through and a non-passing area as an area outside the passing area in an axial direction,
the cover member covers a part of the heat source body corresponding to the non-passing area,
the cover member includes a plurality of through holes formed so as to adjust surface temperature of the heat source body,
the cover member is further composed of an upper plate part at an upper side and lateral plate parts at its both sides and the plurality of through holes are formed in the upper plate part.

2. The fixing device according to claim 1 , wherein
the cover member is configured so that the size and the number of the through holes are determined so as to maintain the surface temperature of the heat source body by a surface limit temperature of the heat source body or less in a fixing operation.

3. The fixing device according to claim 1 , wherein
the cover member has an end part at a side near the center in the axial direction of the fixing belt and the end part is positioned at a position roughly coinciding with a boundary line between the passing area and the non-passing area.

4. The fixing device according to claim 1 , wherein
the nip part has a maximum passing area as an area where the recording medium with a maximum width passes through and a minimum non-passing area as an area outside the maximum passing area in an axial direction,
the cover member has an end part at a side near the center in the axial direction of the fixing belt and the end part is positioned at a position roughly coinciding with a boundary line between the maximum passing area and the minimum non-passing area.

5. The fixing device according to claim 1 further comprising:
a temperature detecting part arranged at an outer circumference side of an end side in the axial direction of the fixing belt and configured so as to detect temperature of the fixing belt,
wherein the cover member covers a part in the heat source body facing to the temperature detecting part in a radial direction.

6. The fixing device according to claim 1 , wherein
the plurality of through holes are formed in a slit-like shape extending in the axial direction of the fixing belt.

7. An image forming apparatus comprising:
a fixing device fixing an image on a recording medium,
the fixing device includes:
an endless fixing belt rotatably arranged around a first rotation axis;
a pressuring member rotatably arranged around a second rotation axis in parallel to the first rotation axis and configured so as to form a nip part pressuring and making the recording medium pass through with the fixing belt;
a heat source body arranged inside the fixing belt and configured so as to have a longitudinal shape extending in roughly parallel to the first rotation axis and to heat the fixing belt by emitting radiant heat; and
a cover member arranged between the fixing belt and the heat source body and configured so as to cover the heat source body,
wherein the nip part has a passing area as an area where the recording medium passes through and a non-passing area as an area outside the passing area in an axial direction,
the cover member covers a part of the heat source body corresponding to the non-passing area,
the cover member includes a plurality of through holes formed so as to adjust surface temperature of the heat source body,
the cover member is further composed of an upper plate part at an upper side and lateral plate parts at its both sides and the plurality of through holes are formed in the upper plate part.

8. The image forming apparatus according to claim 7 , wherein
the cover member is configured so that the size and the number of the through holes are determined so as to maintain the surface temperature of the heat source body by a surface limit temperature of the heat source body or less in a fixing operation.

9. The image forming apparatus according to claim 7 , wherein
the cover member has an end part at a side near the center in the axial direction of the fixing belt and the end part is positioned at a position roughly coinciding with a boundary line between the passing area and the non-passing area.

10. The image forming apparatus according to claim 7 , wherein
the nip part has a maximum passing area as an area where the recording medium with a maximum width passes through and a minimum non-passing area as an area outside the maximum passing area in an axial direction,
the cover member has an end part at a side near the center in the axial direction of the fixing belt and the end part is positioned at a position roughly coinciding with a boundary line between the maximum passing area and the minimum non-passing area.

11. The image forming apparatus according to claim 7 , wherein
the fixing device further includes a temperature detecting part arranged at an outer circumference side of an end side in the axial direction of the fixing belt and configured so as to detect temperature of the fixing belt,
the cover member covers a part in the heat source body facing to the temperature detecting part in a radial direction.

12. The image forming apparatus according to claim 7 , wherein
the plurality of through holes are formed in a slit-like shape extending in the axial direction of the fixing belt.

Assignees

• Kyocera Document Solutions Inc

Inventors

• Eiki Takashi
• Yamagishi Yoshihiro
• Yotsutsuji Takefumi

Classifications

• G03G15/2053 Primary

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

• G03G15/2017

  Structural details of the fixing unit in general, e.g. cooling means, heat shielding means (G03G15/2053 takes precedence) · CPC title

• G03G15/2039 Primary

  with means for controlling the fixing temperature · CPC title