IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of enhancing the efficiency and convenience for determining the abnormality of a sensor. SOLUTION: The apparatus includes: ATC sensors (5Y, 5M, 5C and 5K) for outputting detection values to detect two or more kinds of apparatus states including a remaining amount of toner, an abnormality determining means for determining whether the detection value of the ATC sensor is abnormal or not; an information means for informing a user of the occurrence of the abnormality when determining by the abnormality determining means that the detection value of the ATC sensor is abnormal; and a predicted toner-remaining calculating part 14 for calculating the predicted remaining amount of toner based on the detection result by a toner usage detecting part 13. In the case the predicted remaining amount of toner is equal to or exceeding a prescribed amount when determining by the abnormality determining means that the detection value of the ATC sensor is abnormal, an operation screen including a selection button to select whether or not continuing an image forming operation is displayed, and when the continuity of the image forming operation is selected by the selection button, image formation by the amount of the allowable number of sheets obtained based on the predicted remaining amount of toner is allowed. COPYRIGHT: (C)2008,JPO&INPIT