IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can eliminate both trouble resulting from reflected light detection of a reference toner image and trouble caused by a transmission type photosensor and improve productivity. SOLUTION: The image forming apparatus is provided with a transfer conveyor belt 60 which transfers the reference toner image on a photoreceptor onto its surface while moving, reflection type photosensors 69a and 69b which detect its light transmissivity, and a reflection member 70 which reflects light transmitted through the transfer conveyor belt 60. Further, the image forming apparatus is provided a toner concentration detecting device which detects toner concentration during printing operation, a displacement detecting device which detects a quantity of displacement, a displacement detecting device which interrupts the printing operation and detects the quantity of the displacement, and an image position correcting means of correcting an image position. During the printing operation, the quantity of displacement and toner concentration are detected and when it is recognized that the quantity of the displacement is within a given range and toner concentration detection data is normal, the printing operation is interrupted to detect the displacement and correct an image position. COPYRIGHT: (C)2004,JPO