Fixing device and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9612556-B2
Application number	US-201615052450-A
Country	US
Kind code	B2
Filing date	Feb 24, 2016
Priority date	Mar 17, 2015
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

A fixing device includes a heater to generate heat and a fixing rotator to rotate while contacting the heater. A pressure rotator presses against the heater via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator, through which a recording medium bearing a toner image is conveyed. The heater includes an insulative substrate and a resistive heat generation layer mounted on the substrate. The resistive heat generation layer is disposed upstream from a center of the fixing nip in a recording medium conveyance direction.

First claim

What is claimed is:

1. A fixing device comprising:
a heater to generate heat;
a fixing rotator to rotate while contacting the heater; and
a pressure rotator to press against the heater via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator, the fixing nip through which a recording medium bearing a toner image is conveyed,
the heater including:
an insulative substrate;
a resistive heat generation layer mounted on the substrate, the resistive heat generation layer being disposed upstream from a center of the fixing nip in a recording medium conveyance direction; and
a thermal conductor,

wherein the resistive heat generation layer is disposed opposite the fixing rotator via the thermal conductor.

2. The fixing device according to claim 1 , wherein:
the thermal conductor is separably mounted on the substrate.

3. The fixing device according to claim 2 , wherein:
a thermal conductivity of the thermal conductor is greater than a thermal conductivity of the substrate.

4. The fixing device according to claim 2 ,
wherein the thermal conductor includes a metal plate extended and coupled with the fixing rotator throughout an entire width of the fixing nip in an axial direction of the fixing rotator.

5. The fixing device according to claim 2 ,
wherein the thermal conductor includes a projection projecting from a downstream end of the thermal conductor in the recording medium conveyance direction toward the pressure rotator.

6. The fixing device according to claim 2 ,
wherein the thermal conductor includes a projection tilted toward the pressure rotator in cross-section in a span defined from a downstream end of an upstream portion of the fixing nip to a downstream end of a downstream portion of the fixing nip in the recording medium conveyance direction.

7. The fixing device according to claim 2 ,
wherein the thermal conductor has a substantially uniform thickness at the fixing nip.

8. The fixing device according to claim 7 ,
wherein the resistive heat generation layer adheres to the thermal conductor in a longitudinal direction of the thermal conductor.

9. The fixing device according to claim 7 ,
wherein the heater further includes a thermal conductor supplement sandwiched between the resistive heat generation layer and the thermal conductor, and
wherein the resistive heat generation layer adheres to the thermal conductor via the thermal conductor supplement.

10. The fixing device according to claim 2 ,
wherein a length of the thermal conductor is greater than a length of the fixing nip in the recording medium conveyance direction.

11. The fixing device according to claim 10 ,
wherein the thermal conductor includes an upstream portion disposed upstream from the fixing nip in the recording medium conveyance direction and disposed opposite the resistive heat generation layer.

12. The fixing device according to claim 2 ,
wherein the substrate is contoured along the thermal conductor with substantially no gap between the substrate and the thermal conductor.

13. The fixing device according to claim 2 ,
wherein the substrate is disposed opposite an upstream portion of the fixing nip in the recording medium conveyance direction.

14. The fixing device according to claim 13 , further comprising:
a support disposed opposite a downstream portion of the fixing nip in the recording medium conveyance direction to support the thermal conductor.

15. The fixing device according to claim 14 , further comprising:
a heater holder to support the heater, the heater holder including a projection disposed opposite the downstream portion of the fixing nip in the recording medium conveyance direction to support the thermal conductor.

16. The fixing device according to claim 1 , further comprising:
a nip formation pad to press against the pressure rotator via the fixing rotator to form the fixing nip, the nip formation pad mounting the heater.

17. The fixing device according to claim 1 , further comprising:
a heat source disposed opposite a center span of the fixing rotator in an axial direction of the fixing rotator to heat the fixing rotator,
wherein the heater is disposed opposite a lateral end span of the fixing rotator in the axial direction of the fixing rotator.

18. A fixing device, comprising:
a heater to generate heat;
a fixing rotator to rotate while contacting the heater; and
a pressure rotator to press against the heater via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator, the fixing nip through which a recording medium bearing a toner image is conveyed,
the heater including:
an insulative substrate; and
a resistive heat generation layer mounted on the substrate, the resistive heat generation layer being disposed upstream from a center of the fixing nip in a recording medium conveyance direction; and

a nip formation pad to press against the pressure rotator via the fixing rotator to form the fixing nip, the nip formation pad mounting the heater,
wherein the substrate and the resistive heat generation layer are mounted on a lateral end of the nip formation pad in a longitudinal direction of the nip formation pad.

19. An image forming apparatus comprising:
an image bearer to bear a toner image; and
a fixing device disposed downstream from the image bearer in a recording medium conveyance direction to fix the toner image on a recording medium,
the fixing device including:
a heater to generate heat;
a fixing rotator to rotate while contacting the heater; and
a pressure rotator to press against the heater via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator, the fixing nip through which the recording medium bearing the toner image is conveyed,
the heater including:
an insulative substrate;
a resistive heat generation layer mounted on the substrate, the resistive heat generation layer being disposed upstream from a center of the fixing nip in a recording medium conveyance direction; and
a thermal conductor,

wherein the resistive heat generation layer is disposed opposite the fixing rotator by the thermal conductor.

Assignees

• Ogino Yasuhiko
• Ishii Kenji
• Seto Takashi
• Fujimoto Ippei
• Kishi Kazuhito
• Sawada Kazunari
• Yoshinaga Hiroshi
• Takagi Hiromasa
• Hase Takamasa
• Seo Hiroshi
• Matsusaka Susumu
• Kobashigawa Shohta
• Ricoh Co Ltd

Inventors

• Ogino Yasuhiko
• Ishii Kenji
• Seto Takashi
• Fujimoto Ippei
• Kishi Kazuhito
• Sawada Kazunari
• Yoshinaga Hiroshi
• Takagi Hiromasa
• Hase Takamasa
• Seo Hiroshi
• Matsusaka Susumu
• Kobashigawa Shohta

Classifications

• 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

• G03G15/2064

  combined with pressure · CPC title