Fixing device and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9316977-B2
Application number	US-201414204268-A
Country	US
Kind code	B2
Filing date	Mar 11, 2014
Priority date	Mar 29, 2013
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A fixing device includes an exciting coil to generate a magnetic flux and a heat generation layer disposed opposite the exciting coil to generate heat by the magnetic flux from the exciting coil. A temperature sensitive magnetic body, disposed opposite the exciting coil via the heat generation layer, obtains and loses magnetism at a temperature defined by a Curie temperature by composition adjustment to selectively create a heating region and a non-heating region of the heat generation layer. A degausser is made of a non-magnetic material having an electrical resistivity smaller than an electrical resistivity of the temperature sensitive magnetic body. The degausser is disposed opposite the exciting coil with an interval in a range of from about 4.2 mm to about 8.2 mm.

First claim

What is claimed is:

1. A fixing device comprising:
an exciting coil to generate a magnetic flux;
a heat generation layer disposed opposite the exciting coil to generate heat by the magnetic flux from the exciting coil;
a temperature sensitive magnetic body disposed opposite the exciting coil via the heat generation layer, the temperature sensitive magnetic body to obtain and lose magnetism at a temperature defined by a Curie temperature by composition adjustment to selectively create a heating region and a non-heating region of the heat generation layer; and
a degausser made of a non-magnetic material having an electrical resistivity smaller than an electrical resistivity of the temperature sensitive magnetic body, the degausser disposed opposite the exciting coil with an interval in a range of from about 4.2 mm to about 8.2 mm,
wherein the heat generation layer and the temperature sensitive magnetic body are tubular,
wherein the degausser includes an opposed face disposed opposite the exciting coil and contoured to correspond to an inner circumferential surface of the temperature sensitive magnetic body, and
wherein the opposed face of the degausser is arcuate.

2. The fixing device according to claim 1 , wherein the heat generation layer is made of one of gold and copper.

3. The fixing device according to claim 1 , wherein the heat generation layer has a thickness in a range of from about 3 micrometers to about 30 micrometers.

4. The fixing device according to claim 1 , wherein the degausser is made of a non-magnetic conductor.

5. The fixing device according to claim 4 , wherein the non-magnetic conductor of the degausser is made of one of aluminum and copper.

6. The fixing device according to claim 1 , wherein the degausser is tubular.

7. The fixing device according to claim 1 , wherein the degausser includes an arch having a center angle greater than an angle defined by a circumferential span of the exciting coil disposed opposite the degausser.

8. The fixing device according to claim 1 , further comprising a holder, disposed opposite the exciting coil via the heat generation layer and the temperature sensitive magnetic body, to support the degausser.

9. The fixing device according to claim 1 , further comprising:
a heating roller including the heat generation layer and the temperature sensitive magnetic body; and
a shaft rotatably mounting the heating roller and disposed opposite the heating roller via the degausser.

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

11. The fixing device according to claim 1 , further comprising:
a tubular heating roller including the heat generation layer and the temperature sensitive magnetic body, the tubular heating roller being rotatable.

12. The fixing device according to claim 1 , further comprising:
a tubular heating roller including the heat generation layer and the temperature sensitive magnetic body;
a fixing roller; and
a fixing belt looped over the heating roller and the fixing roller.

13. A fixing device comprising:
an exciting coil to generate a magnetic flux;
a heat generation layer disposed opposite the exciting coil to generate heat by the magnetic flux from the exciting coil;
a temperature sensitive magnetic body disposed opposite the exciting coil via the heat generation layer, the temperature sensitive magnetic body to obtain and lose magnetism at a temperature defined by a Curie temperature by composition adjustment to selectively create a heating region and a non-heating region of the heat generation layer; and
a degausser made of a non-magnetic material having an electrical resistivity smaller than an electrical resistivity of the temperature sensitive magnetic body, the degausser disposed opposite the exciting coil with an interval in a range of from about 4.2 mm to about 8.2 mm,
wherein the heat generation layer and the temperature sensitive magnetic body are tubular, and
wherein the degausser is tubular.

Assignees

• Yamano Motoyoshi
• Tokuda Tetsuo
• Sakamaki Takashi
• Suzuki Naoto
• Ueno Satoshi
• Utsunomiya Kohichi
• Hirose Fumihiro
• Ricoh Co Ltd

Inventors

• Yamano Motoyoshi
• Tokuda Tetsuo
• Sakamaki Takashi
• Suzuki Naoto
• Ueno Satoshi
• Utsunomiya Kohichi
• Hirose Fumihiro

Classifications

• G03G15/2057 Primary

  relating to the chemical composition of the heat element and layers thereof · CPC title

• G03G15/2078

  Physics · mapped topic

• G03G15/2053

  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

  with means for controlling the fixing temperature · CPC title