Image heating apparatus and heater therefor

• US 7,283,145 B2
• Filed: 06/17/2005
• Issued: 10/16/2007
• Est. Priority Date: 06/21/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Iwasaki, Atsushi, Makihira, Tomoyuki, Kato, Akira, Sakai, Hiroaki, Maeda, Masafumi, Takami, Hiroshi, Miura, Seietsu
• Primary Examiner(s): TRAN, HUAN HUU
• Application Number:
  US11/154,545
• Publication Number:
  US 20050280682A1
• Time in Patent Office: 851 Days
• Field of Search: 347/155, 347/156, 347/212, 399/328
• US Class Current: 347/156
• CPC Class Codes: B41J 11/0024 using conduction means, e.g. by using a heated platen
• CPC Class Codes: G03G 15/2042 specially for the axial heat partition
• CPC Class Codes: G03G 2215/2035 the fixing nip having a stationary belt support member opposing a pressure member

Abstract

The n image heating apparatus for heating an image formed on a recording material, includes a heater including a substrate, and plural heat generating resistors formed on the substrate along a longitudinal direction thereof, and plural switching elements connected electrically between a power source and the plural heat generating resistors, wherein the plural heat generating resistors include at least two first heat generating resistors driven by a first switching element and at least a second heat generating resistor driven by a second switching element, and the second heat generating resistor is provided between the at least two first heat generating resistors in a direction of a shorter side of the substrate. In this manner there can be provided an image heating apparatus with a heater of an excellent durability, and a heater adapted for use in such apparatus.

Claims

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

a heater including a substrate and a plurality of heat generating resistors formed on said substrate along a longitudinal direction thereof; and

a plurality of switching elements connected electrically between a power source and said plurality of heat generating resistors;

wherein said plurality of heat generating resistors include at least two first heat generating resistors driven by a first switching element and at least one of a second heat generating resistor driven by a second switching element, and said second heat generating resistor is provided between said first heat generating resistors in a direction of a shorter side of said substrate.

2. An image heating apparatus according to claim 1, wherein said first heat generating resistors are provided substantially symmetrically with respect to an approximate center in a shorter side direction of said substrate.

3. An image heating apparatus according to claim 2, wherein said second heat generating resistor is provided in one unit and is provided at the center.

4. An image heating apparatus according to claim 2, wherein said second heat generating resistors are provided in two units and are provided substantially symmetrically to the center.

5. An image heating apparatus according to claim 1, wherein said first heat generating resistor and said second heat generating resistor have different heat generation distributions.

6. An image heating apparatus according to claim 1, wherein said first and second heat generating resistors are formed on a top surface and a rear surface of said substrate.

7. An image heating apparatus according to claim 1, further comprising a flexible sleeve of which an internal surface is in contact with said heater, and a pressure roller for forming a nip portion with said heater through said flexible sleeve, wherein the recording material is heated while being pinched and conveyed in the nip portion.

8. A heater for use in an image heating apparatus, comprising:

a substrate; and

a plurality of heat generating resistors formed on said substrate along a longitudinal direction thereof;

wherein said plurality of heat generating resistors include at least two first heat generating resistors driven by a first switching element of the image heating apparatus and at least one of a second heat generating resistor driven by a second switching element of the image heating apparatus, and said second heat generating resistor is provided between said first heat generating resistors in a direction of a shorter side of said substrate.

9. A heater according to claim 8, wherein said first heat generating resistors are provided substantially symmetrically with respect to an approximate center in a shorter side direction of said substrate.

10. A heater according to claim 9, wherein said second heat generating resistor is provided in one unit and is provided at the center.

11. A heater according to claim 9, wherein said second heat generating resistors are provided in two units and are provided substantially symmetrically to the center.

12. A heater according to claim 8, wherein said first heat generating resistor and said second heat generating resistor have different heat generation distributions.

13. A heater according to claim 8, wherein said first and second heat generating resistors are formed on a top surface and a rear surface of said substrate.