Fixing device including a pressure pad with at least one mouth, and image forming apparatus incorporating same

Patent metadata

Field	Value
Publication number	US-10025247-B2
Application number	US-201715447709-A
Country	US
Kind code	B2
Filing date	Mar 2, 2017
Priority date	Mar 11, 2016
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A fixing device includes fixing rotator, a heater to heat the fixing rotator, a pressure rotator disposed opposite an outer circumferential surface of the fixing rotator, a pressure pad disposed opposite an inner circumferential surface of the fixing rotator, a support to support the pressure pad, and a thermal conduction aid to conduct heat in an axial direction of the fixing rotator. The pressure pad presses against the pressure rotator via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator. The pressure pad includes a nip-side face disposed opposite the inner circumferential surface of the fixing rotator. The thermal conduction aid covers the nip-side face of the pressure pad. The nip-side face of the pressure pad includes at least one mouth therein defining a non-contact area in which the pressure pad does not contact the thermal conduction aid.

First claim

What is claimed is:

1. A fixing device comprising:
a fixing rotator formed into a loop and rotatable in a predetermined direction of rotation;
a heater to heat the fixing rotator;
a pressure rotator disposed opposite an outer circumferential surface of the fixing rotator;
a pressure pad disposed opposite an inner circumferential surface of the fixing rotator to press against the pressure rotator via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator,
the pressure pad including a nip-side face disposed opposite the inner circumferential surface of the fixing rotator;
a support to support the pressure pad; and
a thermal conduction aid to conduct heat in an axial direction of the fixing rotator,
the thermal conduction aid covering the nip-side face of the pressure pad,
the nip-side face of the pressure pad including at least one mouth defining a non-contact area of the pressure pad in the at least one mouth, in which the pressure pad does not contact the thermal conduction aid, and
the support contacts the pressure pad in a range corresponding to the non-contact area of the pressure pad as seen from the nip-side face of the pressure pad.

2. The fixing device according to claim 1 , wherein the pressure pad further comprises a convex contact portion coupled to the support, and
wherein the convex contact portion of the pressure pad contacts the support in a range corresponding to the non-contact area as seen from the nip-side face of the pressure pad.

3. The fixing device according to claim 1 , wherein the support further comprises a convex contact portion coupled to the pressure pad, and
wherein the convex contact portion of the support contacts the pressure pad in a range corresponding to the non-contact area as seen from the nip-side face of the pressure pad.

4. The fixing device according to claim 1 , wherein the at least one mouth of the pressure pad has a continuous, identical width over a given length in a longitudinal direction of the pressure pad.

5. The fixing device according to claim 4 , wherein the at least one mouth of the pressure pad includes a first mouth and a second mouth, and
wherein the first mouth and the second mouth are arranged side by side in a short direction of the pressure pad.

6. The fixing device according to claim 1 , wherein the nip-side face of the pressure pad further includes a contact area in which the pressure pad contacts the thermal conduction aid, and
wherein the contact area includes at least a position at which the nip-side face of the pressure pad is subjected to a maximum pressure.

7. The fixing device according to claim 1 , wherein a size and a number of the at least one mouth is determined such that the nip-side face of the pressure pad is subjected to a desired surface pressure.

8. The fixing device according to claim 5 , wherein the second mouth is disposed upstream from the first mouth in a direction of recording medium conveyance,
wherein each of the first mouth and the second mouth defines a non-contact area in which the pressure pad does not contact the thermal conduction aid, and

wherein the non-contact area defined by the second mouth is larger than the non-contact area defined by the first mouth.

9. The fixing device according to claim 1 , wherein the at least one mouth is disposed inboard from opposed lateral ends of the thermal conduction aid in a longitudinal direction of the thermal conduction aid.

10. The fixing device according to claim 1 , further comprising a lateral end heater on a lateral end of the pressure pad in a longitudinal direction of the pressure pad.

11. The fixing device according to claim 10 , wherein the lateral end heater is a contact-type, heat-transfer heater.

12. The fixing device according to claim 1 , wherein the fixing rotator is a flexible, endless belt.

13. The fixing device according to claim 1 , wherein the pressure pad has a shape conforming to a shape of the thermal conduction aid.

14. An image forming apparatus comprising:
an image forming device to form a toner image; and
the fixing device according to claim 1 ,
the fixing device being disposed downstream from the image forming device in a direction of recording medium conveyance to fix the toner image on a recording medium.

15. A fixing device comprising:
a fixing rotator formed into a loop and rotatable in a predetermined direction of rotation;
a heater to heat the fixing rotator;
a pressure rotator disposed opposite an outer circumferential surface of the fixing rotator;
a pressure pad disposed opposite an inner circumferential surface of the fixing rotator to press against the pressure rotator via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator,
the pressure pad including a nip-side face disposed opposite the inner circumferential surface of the fixing rotator;
a support to support the pressure pad; and
a thermal conduction aid to conduct heat in an axial direction of the fixing rotator,
the thermal conduction aid covering the nip-side face of the pressure pad,
the nip-side face of the pressure pad including at least one mouth defining a non-contact area of the pressure pad in the at least one mouth, in which the pressure pad does not contact the thermal conduction aid,
the nip-side face of the pressure pad further includes a contact area in which the pressure pad contacts the thermal conduction aid, and
the contact area includes at least a position at which the nip-side face of the pressure pad is subjected to a maximum pressure.

16. A fixing device comprising:
a fixing rotator formed into a loop and rotatable in a predetermined direction of rotation;
a heater to heat the fixing rotator;
a pressure rotator disposed opposite an outer circumferential surface of the fixing rotator;
a pressure pad disposed opposite an inner circumferential surface of the fixing rotator to press against the pressure rotator via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator,
the pressure pad including a nip-side face disposed opposite the inner circumferential surface of the fixing rotator;
a support to support the pressure pad; and
a thermal conduction aid to conduct heat in an axial direction of the fixing rotator,
the thermal conduction aid covering the nip-side face of the pressure pad,
the nip-side face of the pressure pad including at least one mouth defining a non-contact area of the pressure pad in the at least one mouth, in which the pressure pad does not contact the thermal conduction aid, and
a size and a number of the at least one mouth is determined such that the nip-side face of the pressure pad is subjected to a desired surface pressure.

Assignees

• Sawada Kazunari
• Fujimoto Ippei
• Ishii Kenji
• Seto Takashi
• Seki Takayuki
• Yoshinaga Hiroshi
• Matsuda Ryohei
• Ricoh Co Ltd

Inventors

• Sawada Kazunari
• Fujimoto Ippei
• Ishii Kenji
• Seto Takashi
• Seki Takayuki
• Yoshinaga Hiroshi
• Matsuda Ryohei

Classifications

• G03G2215/2035

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

• G03G15/2064

  combined with pressure · CPC title

• G03G15/206 Primary

  Structural details or chemical composition of the pressure elements and layers thereof · CPC title

• G03G15/2089 Primary

  Physics · mapped topic

• G03G15/2053 Primary

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