Cylindrical film and image heating apparatus

Patent metadata

Field	Value
Publication number	US-11194271-B2
Application number	US-201916558846-A
Country	US
Kind code	B2
Filing date	Sep 3, 2019
Priority date	Sep 4, 2018
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

A cylindrical film for use with an image heating apparatus includes a plurality of heat generating elements configured to generate heat by a flow of a current, in which each of the heat generating elements has a ring shape and is arranged along a longitudinal direction of the film; a ring-shaped insulating portion configured to electrically insulate the heat generating elements adjacent to each other; and a heat conductive layer different from a layer of the heat generating elements with respect to a thickness direction of the film, The heat conductive layer is 3 W/mK or more in thermal conductivity and overlaps with the heat generating elements with respect to the longitudinal direction.

First claim

What is claimed is;:

1. A cylindrical film for use with an image heating apparatus, comprising:
a cylindrical base layer made of a polyimide, a polyamideimide, a carbon fiber reinforced plastic, or a glass fiber reinforced plastic;
a plurality of heat generating layers configured to generate heat by a flow of current, wherein each of the heat generating layers has a ring shape and is arranged on the base layer along a longitudinal direction of the film;
a ring-shaped insulating portion configured to electrically insulate the heat generating layers adjacent to each other; and
a heat conductive layer different from a layer of the heat generating layers with respect to a thickness direction of the film,
wherein the heat conductive layer is electrically insulative, and
wherein the heat conductive layer is 3 W/mK or more in thermal conductivity and overlaps with the heat generating layers with respect to the longitudinal direction of the film.

2. The cylindrical film according to claim 1 , wherein the heat conductive layer also functions as the insulating portion.

3. The cylindrical film according to claim 2 , wherein the heat conductive layer comprises:
at least one resin material selected from the group consisting of a polyimide, a polyamideimide, an acrylic resin,. and an epoxy resin; and
at least one heat conductive filler selected from the group consisting of magnesium oxide, aluminum oxide, boron nitride, aluminum nitride, silicon dioxide,. and titanium oxide, and
wherein the heat conductive filler is dispersed in the resin material.

4. The cylindrical film according to claim 1 , wherein the heat conductive layer is provided outside the heat generating layers with respect to the thickness direction of the film.

5. The cylindrical film according to claim 1 , wherein the heat conductive layer is provided inside the heat generating layers with respect to the thickness direction of the film.

6. An image heating apparatus for heating an image formed on a recording material, comprising:
a cylindrical film rotatable while contacting the recording material;
a roller contacting an outer surface of the film and configured to form a nip, in which the recording material is nipped and fed, between itself and the film; and
an exciting coil unit configured to generate an induced current flowing through the film in a circumferential direction,
wherein the film includes:
a cylindrical base layer made of a polyimide, a polyamideimide, a carbon fiber reinforced plastic, or a glass fiber reinforced plastic;
a plurality of heat generating layers configured to generate heat by a flow of the induced current, wherein each of the heat generating layers has a ring shape and is arranged on the base layer along a longitudinal direction of the film;
a ring-shaped insulating portion configured to electrically insulate the heat generating layers adjacent to each other; and
a heat conductive layer different from a layer of the heat generating layers with respect to a thickness direction of the film,
wherein the heat conductive layer is electrically insulative, and
wherein the heat conductive layer is 3 W/mK or more in thermal conductivity and overlaps with the heat generating layers with respect to the longitudinal direction of the film.

7. The image heating apparatus according to claim 6 , wherein the heat conductive layer also functions as the insulating portion.

8. The image heating apparatus according to claim 7 , wherein the heat conductive layer comprises:
at least one resin material selected from the group consisting of a polyimide, a polyamideimide, an acrylic resin, and an epoxy resin; and
at least one heat conductive filler selected from the group consisting of magnesium oxide, aluminum oxide, boron nitride, aluminum nitride, silicon dioxide, and titanium oxide, and
wherein the heat conductive filler is dispersed in the resin material.

9. The image heating apparatus according to claim 6 , wherein the heat conductive layer is provided outside the heat generating layers with respect to the thickness direction of the film.

10. The image heating apparatus according to claim 6 , wherein the heat conductive layer is provided inside the heat generating layers with respect to the thickness direction of the film.

11. The image heating apparatus according to claim 6 , wherein the sexciting coil unit is provided in an inner space of the film,
wherein the exciting coil unit includes an exciting coil having a helical axis parallel to the longitudinal direction of the film and a core provided in the exciting coil along the longitudinal direction of the film,
wherein the core has a non-endless shape having end portions at positions corresponding to one end portion and another end portion, respectively, of the film with respect to the longitudinal direction of the film, and
wherein 90% or more of magnetic flux generated from opposite ends of the core by the exciting coil unit passes through an outside of the film with respect to a radial direction of the film.

Assignees

• Canon Kk

Inventors

• Fujimoto Tetsuichiro

Classifications

• G03G15/2053 Primary

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

• H05B6/145

  Heated rollers · CPC title

• G03G15/2057 Primary

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