| CPC G03G 15/2039 (2013.01) [G03G 15/2053 (2013.01); G03G 15/5004 (2013.01); H05B 3/0095 (2013.01); G03G 2215/00805 (2013.01); H05B 2203/007 (2013.01)] | 19 Claims |
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1. An image heating apparatus comprising:
a tubular film;
a heater that is disposed in an inner space of the film and includes a plurality of heating elements arranged in a longitudinal direction of the heater, which is a direction perpendicular to a conveyance direction of a recording material;
a roller that is in contact with an outer peripheral surface of the film, and sandwiches the film with the heater, and forms a nip portion with the film, where a recording material on which a toner image is formed is sandwiched and conveyed;
a plurality of temperature detecting portions configured to detect respective temperatures of a plurality of heating regions which are heated by the plurality of heating elements respectively;
an acquiring portion configured to acquire recording material information including a size of a recording material; and
a control portion, wherein
in the image heating apparatus, the control portion individually controls the plurality of heating elements based on the recording material information, and the toner image is heated in the nip portion, wherein
the plurality of heating regions include
a reference heating region that is specified as a heating region, which includes a conveyance reference position of the recording material, and
a first heating region that is specified as a passing heating region, which does not include the conveyance reference position and which the recording material passes through, by the recording material information, wherein
in a case of performing heating processing consecutively on a plurality of recording materials,
the control portion acquires a deviation of a difference between a control target temperature and a detected temperature by a temperature detecting portion in the first heating region, with respect to a difference between a control target temperature and a detected temperature by a temperature detecting portion in the reference heating region; and
determines whether the first heating region is actually the passing heating region or a non-passing heating region which a recording material does not pass through, based on whether the deviation is within a predetermined range or not, and
in a case where it is determined that the first heating region is the non-passing heating region, the control portion performs a prevention control to prevent overheat of the first heating region in heating processing of the recording material that passes through the nip portion after the determination.
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