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EP0564420A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Image heating device capable of controlling activation of plural heaters

Assignee: Canon Inc
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Filing: 1993-03-29
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Granted: —
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Expires: 2013-03-29
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Abstract

Abstract Disclosed is an image heating device for a fixing device in an image forming apparatus. The image heating device is provided with two heaters (49,50) and an image fixing roller (45). The image fixing roller (45) is heated by the two heaters (49,50), one having the heat distribution in the center and the other having the heat distribution in the end portion of the fixing roller (45). The heaters (49,50) are alternately energized so that the power requirement is maintained limited. The energization time ratio of the heaters (49,50) is suitably varied according to the sheet size in order to compensate the temperature loss in the end portions when the heating is conducted in the central portion only, or to reduce the temperature rise in the end portions, encountered when narrow sheets are consecutively passed, thereby preventing various drawbacks resulting from uneven temperature distribution on the fixing roller (45).

Inventors

  • 👤 Saijiro c/o Canon Kabushiki Kaisha Endo
  • 👤 Yoshikuni c/o Canon Kabushiki Kaisha Toyama
  • 👤 Hisaaki C/O Canon Kabushiki Kaisha Senba
  • 👤 Hisatsugu C/O Canon Kabushiki Kaisha Tahara
  • 👤 Hiroshi c/o Canon Kabushiki Kaisha Matsumoto
  • 👤 Keisuke c/o Canon Kabushiki Kaisha Hasegawa

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 06:44
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/20; G03G15/2003; G03G15/2014; G03G15/2039; G03G15/2042

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 56 words
An image heating device comprising: a heating member including a first heater and a second heater of a heat distribution different from that of said first heater; a back-up member forming a nip with said heating member; and power supply control means for effecting time-shared control of supplying electric power to said first and second heaters.
Claim 2
Dependent Claim 49 words
An image heating device according to claim 1, wherein the heat distribution of said first heater substantially corresponds to a recording member of a small size, and the heat distribution of said second heater substantially corresponds to a portion where said recording member of small size does not pass.
Claim 3
Dependent Claim 47 words
An image heating device according to claim 1, wherein said first heater has the heat distribution which is higher in a central portion than in end portions, and said second heater has the heat distribution which is higher in the end portions than in the central portion.
Claim 4
Dependent Claim 35 words
An image heating device according to claim 1, wherein said power supply control means is adapted to control an energization ratio of said first and second heaters according to the size of the recording member.
Claim 5
Dependent Claim 45 words
An image heating device according to claim 1, wherein said power supply control means is adapted to vary the energization ratio of said first and second heaters between a state that the recording member passes and another state that the recording member does not pass.
Claim 6
Dependent Claim 61 words
An image heating device according to claim 1, further comprising a temperature detecting member for detecting the temperature of a portion, where the recording member does not pass, of said heating member, wherein said power supply control means is adapted to control the energization ratio of said first and second heaters according to the temperature detected by said temperature detecting member.
Claim 7
Dependent Claim 40 words
An image heating device according to claim 1, wherein said power supply control means is adapted to control the energization ratio of said first and second heaters according to the size and the continuously passed number of the recording member.
Claim 8
Dependent Claim 39 words
An image heating device according to claim 1, wherein said power supply control means is adapted to control the energization ratio of said first and second heaters after termination of image heating according to conditions of said image heating.
Claim 9
Dependent Claim 48 words
An image heating device according to claim 1, wherein said power supply control means is adapted to control the energization ratio of said first and second heaters according to the size of the recording material and the number of image heating operations in a preceding image heating operation.

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