Image heating apparatus and image forming apparatus

摘要

A control portion executes a measuring mode and generates a value for adjusting a pressurizing mechanism reflecting a difference of pressurizing conditions of a longitudinal center part and a longitudinal end part of a nip portion. The measuring mode is a mode of detecting temperatures of the nip portion by temperature detecting elements in a process of changing temperature of the nip portion heated by a heater and of generating control information based on detected results. The control information is generated in response to a difference of temperature increase amounts of the temperature detecting elements in a predetermined time in the process of increasing the temperature of the nip portion. The control portion adjusts the pressurizing mechanism based on the control value obtained in the measuring mode after executing a process of heating a recording medium in succession of the process of increasing the temperature of the nip portion.

主权项

1. An image heating apparatus, comprising:
an endless belt member that comes in contact with an image surface of a recording medium; a support structure configured to be irrotational, to support an inner side surface of the belt member, and to heat the belt member; a roller member configured to come into contact with the belt member supported by the support structure and to form a nip portion; a pressurizing mechanism configured to form the nip portion by generating a pressurizing force between the support structure and the roller member; a first temperature sensor that detects the temperature of a longitudinal center part of the support structure; a second temperature sensor that detects the temperature of a longitudinal end part of the support structure; and a control portion configured to execute a measuring mode in which the control portion detects the temperatures by the first and second temperature sensors in a process of changing the temperature of the nip portion heated by the support structure, and to generate control information reflecting the difference of pressurizing conditions of the longitudinal end part and the longitudinal center part of the nip portion based on detected results.