Heater having at least one cycle path resistor and image heating apparatus therein

• US 20030196999A1
• Filed: 04/17/2003
• Published: 10/23/2003
• Est. Priority Date: 04/22/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ogawa, Kenichi, Sakakibara, Hiroyuki, Kato, Akira, Tomoyuki, Yoji, Nakazono, Yusuke
• Granted Patent: US 6,734,397 B2
• Time in Patent Office: Days
• US Class Current: 219/216
• CPC Class Codes: H05B 3/0095 Heating devices in the form of rollers heated by induction H05B6/145

Abstract

A heater, or an image heating apparatus including the heater includes a substrate, heat generating resistors formed at least in a cycle path on the substrate, and current supply electrodes provided at electrical ends of the heat generating resistors, wherein plural heat generating resistors are connected in parallel to at least one of the current supply electrodes. Thus there can be obtained a heater having excellent heat generating characteristics even in a compact dimension and an image heating apparatus utilizing such heater.

Claims

1. A heater comprising:

a substrate;

heat generating resistors formed at least in a cycle path including a forward path and a return path on said substrate; and

current supply electrodes provided at electrical ends of said heat generating resistors;

wherein plural heat generating resistors are connected in parallel to at least one of said current supply electrodes.

2. A heater according to claim 1, wherein, in both the forward path and the return path of said heat generating resistor, a plurality of said heat generating resistors are connected in parallel to said current supply electrode.

3. A heater according to claim 1, wherein a plurality of said heat generating resistors are connected in parallel to one of said current supply electrodes, and a heat generating resistor is connected to the other of said current supply electrodes.

4. A heater according to claim 1, wherein said plural heat generating resistors connected in parallel are electrically connected in plural positions in the longitudinal direction of said substrate.

5. A heater according to claim 1, further comprising a surface layer on said heat generating resistors, wherein said surface layer fills in gaps between said heat generating resistors to improve an irregularity.

6. A heater according to claim 1, wherein said plural heat generating resistors have respectively different resistances.

7. An image heating apparatus for heating an image formed on a recording material, comprising:

a heater, including a substrate, heat generating resistors formed at least in a cycle path including a forward path and a return path on said substrate, and current supply electrodes provided at electrical ends of said heat generating resistors; and

a flexible sleeve rotating in sliding contact with said heater;

wherein a plurality of said heat generating resistors are connected in parallel to at least one of said current supply electrodes.

8. An image heating apparatus according to claim 7, wherein, in both the forward path and the return path of said heat generating resistor, a plurality of said heat generating resistors are connected in parallel to said current supply electrode.

9. An image heating apparatus according to claim 7, wherein a plurality of said heat generating resistors are connected in parallel to one of said current supply electrodes, and a heat generating resistor is connected to the other of said current supply electrodes.

10. An image heating apparatus according to claim 9, wherein said current supply electrode to which a heat generating resistor is connected is an electrode at an upstream side in the moving direction of the recording material.

11. An image heating apparatus according to claim 7, wherein said plural heat generating resistors connected in parallel are electrically connected in plural positions in the longitudinal direction of said substrate.

12. An image heating apparatus according to claim 7, further comprising a surface layer on said heat generating resistors, wherein said surface layer fills in gaps between said heat generating resistors to improve an irregularity.

13. An image heating apparatus according to claim 7, wherein said plural heat generating resistors have respectively different resistances.

14. A heater comprising:

a substrate;

heat generating resistors provided on said substrate and formed by resistors of different resistances connected serially at least in two cycle paths.

15. A heater according to claim 14, further comprising a surface layer on said heat generating resistors, wherein said surface layer fills in gaps between said heat generating resistors to form a flat surface.

16. An image heating apparatus for heating an image formed on a recording material, comprising:

a heater, including a substrate, heat generating resistors provided on said substrate and formed by resistors of different resistances connected serially at least in two cycle paths, and current supply electrodes provided at electrical ends of said heat generating resistors; and

a flexible sleeve rotating in sliding contact with said heater.

17. A heater according to claim 16, wherein said plural resistors have resistances gradually changing in a moving direction of the recording material.

18. A heater according to claim 16, further comprising a surface layer on said heat generating resistors, wherein said surface layer fills in gaps between said heat generating resistors to improve an irregularity.