Patent ID: 8218983
Filing Date: 2012-07-10
Classification: G03G

Abstract:
1. An image formation apparatus comprising: a rotatable heat roller; a first temperature sensor detecting a temperature at a position at a prescribed distance from a surface of said heat roller; a second temperature sensor detecting an ambient temperature of said first temperature sensor; a storage portion storing a temperature table in which a surface temperature of said heat roller is defined in association with a combination of a first input value and a second input value obtained by said first temperature sensor and said second temperature sensor, and a transition destination table in which a weight for a transition from each element to an adjacent element is defined in association with each element of said temperature table; a temperature estimation portion estimating said surface temperature, in accordance with said temperature table, based on first and second input values; a temperature increase portion increasing the temperature of said heat roller according to the estimated surface temperature of said heat roller; and a determination portion successively integrating said weight every time an element corresponding to a combination of said first input value and said second input value makes a transition to an adjacent element, during a temperature increase of said heat roller by said temperature increase portion, and determining whether a malfunction occurs or not in said first or second temperature sensor, based on said integrated weight.