Image heating apparatus and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9280102-B2
Application number	US-201314083994-A
Country	US
Kind code	B2
Filing date	Nov 19, 2013
Priority date	Nov 30, 2012
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

An image heating apparatus includes: a rotatable heating member; a belt unit including an endless belt configured to heat the rotatable heating member, and a supporting portion configured to rotatably support an inner surface of the belt; a holding portion configured to rotatably hold the belt unit; a detecting portion configured to detect that the belt is out of a predetermined zone with respect to a widthwise direction of the belt; a tilting portion configured to tilt the belt unit relative to the holding portion in a direction of causing the belt to return into the predetermined zone on the basis of an output of the detecting portion; and a limiting portion configured to limit tilting of the belt unit to an angle exceeding a predetermined angle range wider than an angle range in which the belt unit is capable of being tilted by the tilting portion.

First claim

What is claimed is:

1. An image heating apparatus comprising:
a rotatable heating member configured to heat an image on a sheet;
a belt unit including an endless belt configured to heat said rotatable heating member by contacting an outer surface of said rotatable heating member, and first and second supporting members configured to rotatably support an inner surface of said endless belt;
a holding mechanism configured to rotatably hold said belt unit;
a detector configured to detect that said endless belt is out of a predetermined zone with respect to a widthwise direction of said endless belt;
a tilting device configured to tilt said belt unit relative to said holding mechanism in a direction of causing said endless belt to return into the predetermined zone on the basis of an output of said detector; and
a limiting mechanism configured to limit tilting of said belt unit to an angle exceeding a predetermined angle range wider than an angle range in which said belt unit is capable of being tilted by said tilting device.

2. An image heating apparatus according to claim 1 , wherein said limiting mechanism is provided on said holding mechanism.

3. An image heating apparatus according to claim 1 , wherein each of said first and second supporting members is a roller in which a heater is incorporated.

4. An image heating apparatus according to claim 1 , further comprising
a driving mechanism configured to rotationally drive said rotatable heating member,
wherein said endless belt is constituted so as to be rotated by rotation of said rotatable heating member.

5. An image heating apparatus according to claim 1 , wherein said rotatable heating member is a roller.

6. An image heating apparatus according to claim 1 , further comprising a nip forming member configured to form a nip for nipping and conveying the sheet between said nip forming member and said rotatable heating member.

7. An image heating apparatus comprising:
a rotatable heating member configured to heat a toner image on a sheet;
a belt unit including an endless belt configured to heat said rotatable heating member by contacting an outer surface of said rotatable heating member, and first and second rollers configured to rotatably support an inner surface of said endless belt;
a detector configured to detect a widthwise position of said endless belt;
a tilting device configured to tilt, on the basis of an output of said detector, said belt unit so that an axis of each of said first and second rollers in a state in which said rollers press said endless belt against said rotatable heating member crosses with a generatrix of said rotatable heating member; and
a limiting mechanism configured to limit tilting of said belt unit to an angle exceeding a predetermined angle range wider than an angle range of said belt unit tilted by said tilting device.

8. An image heating apparatus according to claim 7 , wherein said limiting mechanism is provided on said holding mechanism.

9. An image heating apparatus according to claim 7 , wherein each of said first and second rollers includes a heater incorporated therein.

10. An image heating apparatus according to claim 7 , further comprising a driving mechanism configured to rotationally drive said rotatable heating member,
wherein said endless belt is constituted so as to be rotated by rotation of said rotatable heating member.

11. An image heating apparatus according to claim 7 , wherein said rotatable heating member is a roller.

12. An image heating apparatus according to claim 7 , further comprising a nip forming member configured to form a nip for nipping and conveying the sheet between said nip forming member and said rotatable heating member.

13. An image heating apparatus comprising:
a rotatable heating member configured to heat a toner image on a sheet;
an endless belt configured to heat said rotatable heating member by contacting an outer surface of said rotatable heating member;
two rollers configured to rotatably support an inner surface of said endless belt;
a supporting mechanism configured to support said two rollers;
a holding mechanism configured to swingably hold said supporting mechanism;
a detector configured to detect a widthwise position of said endless belt;
a swinging device configured to swing, on the basis of an output of said detector, said supporting mechanism relative to said holding mechanism so that each of said two rollers in a state in which said two rollers press said endless belt against said rotatable heating member crosses with said rotatable heating member; and
a limiting mechanism configured to limit swinging of said supporting mechanism relative to said holding mechanism to an angle exceeding a predetermined angle range wider than an angle range in which said belt unit is capable of being swung by said swinging device.

14. An image heating apparatus according to claim 13 , wherein said swinging device is provided on an opposite side from said rotatable heating member with respect to said endless belt and has a swinging shaft which is positioned between said two rollers and which is substantially parallel to a direction of normal to a flat surface of said endless belt in a side remote from said rotatable heating member, and
wherein said swinging device swings said holding mechanism about the swinging shaft on the basis of an output of said detector.

15. An image heating apparatus comprising:
a rotatable heating member configured to heat an image on a sheet;
a belt unit including an endless belt configured to heat said rotatable heating member by contacting an outer surface of said rotatable heating member, and first and second supporting members configured to rotatably support an inner surface of said endless belt;
a detector configured to detect that said endless belt is out of a predetermined zone with respect to a widthwise direction of said endless belt;
a tilting device configured to tilt said belt unit in a direction of causing said endless belt to return into the predetermined zone on the basis of an output of said detector; and
a limiting mechanism configured to limit tilting of said belt unit.

16. An image heating apparatus according to claim 15 , wherein said tilting device tilts said belt unit within a predetermined angle range about a predetermined tilt center, and
wherein said limiting mechanism-limits the tilting of said belt unit to an angle exceeding an angle range wider than the predetermined angle range.

17. An image forming apparatus comprising:
a belt unit including an endless belt and first and second supporting members configured to rotatably support an inner surface of said endless belt;
a rotatable driving member configured to rotate said endless belt by rotation thereof in contact with an outer surface of said endless belt;
a holding mechanism configured to rotatably hold said belt unit;
a detector configured to detect that said endless belt is out of a predetermined zone with respect to a widthwise direction of said endless belt;
a tilting device configured to tilt said belt unit relative to said holding mechanism in a direction of causing said endless belt to return into the predetermined zone on the basis of an output of said detector; and
a limiting mechanism configured to limit tilting of said belt unit to an angle exceeding a predetermined angle range wider than an angle range in which said belt unit is capable of being tilted by said tilting device.

18. An image forming apparatus comprising:
a belt unit including an endless belt and first and second roll

Assignees

• Canon Kk

Inventors

• Hasegawa Takuya

Classifications

• G03G2215/00143

  Meandering prevention · CPC title

• G03G15/2039 Primary

  with means for controlling the fixing temperature · CPC title

• G03G15/2053 Primary

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

• G03G2215/2019

  the belt not heating the toner or medium directly, e.g. heating a heating roller · 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