Patent ID: 7890009
Filing Date: 2011-02-15
Classification: G03G

Abstract:
1. An image forming apparatus in which a recording material is set to be conveyed according to a paper feeding reference at a center in a width direction, comprising: a paper feeding tray; a presence or absence sensor for detecting a presence or absence of the recording material on the paper feeding tray; a top sensor for detecting a leading edge of the recording material; a width detection sensor for detecting a width of the recording material; a fixing part for fixing an unfixed image formed on the recording material, said fixing part including a heat member for heating the unfixed image formed on the recording material; a central portion temperature detection part that detects a temperature of a central region of the heat member in a direction perpendicular to a conveyance direction of the recording material; an end portion temperature detection part that detects a temperature of an end portion region of the heat member in the direction perpendicular to the conveyance direction of the recording material; and a control part that controls a power supply to said heat member to maintain a temperature detected by said central portion temperature detection part at a set fixing temperature; wherein in a case where the recording material is conveyed so that a center in a width direction of a small sized recording material moves along the paper feeding reference, said presence or absence sensor and said top sensor are provided in a conveyance area of the small sized recording material in the direction perpendicular to the conveyance direction of the recording material, and said width detection sensor and said end portion temperature detection part are provided outside the conveyance area of the small sized recording material in the direction perpendicular to the conveyance direction of the recording material, wherein said width detection part is disposed at a side opposite to a side at which said end portion temperature detection part is disposed with respect to the paper feeding reference, and wherein in a case where the recording material is detected by said presence or absence sensor, said top sensor and said width detection sensor, and a temperature detected by said end portion temperature detection part rises while said fixing part performs a fixing-process, or in a case where the recording material is detected by said presence or absence sensor and said top sensor and not detected by said width detection sensor, and a temperature detected by said end portion temperature detection part does not rise while said fixing part performs a fixing-process, said control part controls a power supply supplied to said heat member or a conveyance interval of the recording material so that a temperature of a non-sheet feeding region of said heat member is equal to or less than an allowable temperature.