Image heating apparatus that determines if a region is a passing region based on a temperature deviation related to a reference heating region, and image forming apparatus

An image forming apparatus for forming a toner image on a recording material, comprising:

• an image forming portion configured to form the toner image on the recording material;
• a fixing portion configured to fix the toner image formed on the recording material to the recording material, the fixing portion includes
• a tubular film,
• a heater disposed in an inner space of the film and includes a plurality of heating blocks arranged on a substrate in a longitudinal direction of the heater, which is a direction perpendicular to a conveyance direction of a recording material, wherein the plurality of heating blocks includes a first heating block provided at a conveyance reference position of the recording material with respect to the longitudinal direction and a second heating block provided at a position different from the first heating block with respect to the longitudinal direction,
• a roller configured to contact with an outer peripheral surface of the film to form a nip portion, where the recording material on which the toner image is formed is sandwiched and conveyed, in cooperation with the heater through the film,
• a first temperature detecting element configured to detect a temperature of the first heating block, and
• a second temperature detecting element configured to detect a temperature of the second heating block,
• a first TRIAC configured to switch between a power supply state and a power supply cutoff state to the first heating block;
• a second TRIAC configured to switch between a power supply state and a power supply cutoff state to the second heating block;
• and
• a controller, the controller controls the first TRIAC so that the temperature detected by the first temperature detecting element is maintained at a target temperature and controls the second TRIAC so that the temperature detected by the second temperature detecting element is maintained at a target temperature,
• wherein in a state where the recording material is conveyed at the nip portion and a fixing process is performed, the controller determines whether or not a size of the recording material set by a user matches the size of the recording material actually conveyed at the nip portion in accordance with an information including the size of the recording material set by the user, the temperature of the first heating block detected by the first temperature detecting element, and the temperature of the second heating block detected by the second temperature detecting element.

An image forming apparatus for forming a toner image on a recording material, comprising:

• an image forming portion configured to form the toner image on the recording material;
• a fixing portion configured to fix the toner image formed on the recording material to the recording material, the fixing portion includes
• a tubular film,
• a heater disposed in an inner space of the film and includes a plurality of heating blocks arranged on a substrate in a longitudinal direction of the heater, which is a direction perpendicular to a conveyance direction of a recording material, wherein the plurality of heating blocks includes a first heating block provided at a conveyance reference position of the recording material with respect to the longitudinal direction and a second heating block provided at a position different from the first heating block with respect to the longitudinal direction,
• a roller configured to contact with an outer peripheral surface of the film to form a nip portion, where the recording material on which the toner image is formed is sandwiched and conveyed, in cooperation with the heater through the film,
• a first temperature detecting element configured to detect a temperature of the first heating block, and
• a second temperature detecting element configured to detect a temperature of the second heating block,
• a first TRIAC configured to switch between a power supply state and a power supply cutoff state to the first heating block;
• a second TRIAC configured to switch between a power supply state and a power supply cutoff state to the second heating block;
• and
• a controller, the controller controls the first TRIAC so that the temperature detected by the first temperature detecting element is maintained at a target temperature and controls the second TRIAC so that the temperature detected by the second temperature detecting element is maintained at a target temperature,
• wherein in a state where the recording material is conveyed at the nip portion and a fixing process is performed, the controller determines whether or not a size of the recording material set by a user matches the size of the recording material actually conveyed at the nip portion in accordance with an information including the size of the recording material set by the user, the target temperature of the second heating block, and the temperature of the second heating block detected by the second temperature detecting element.