An image forming apparatus 100 includes an intermediate transfer belt 21, a reading section 25, and an intermediate transfer unit 2 having a supplementary roller 26. The photo TFTs each have their respective gate electrodes shorted to source electrodes to increase generated photocurrent. The reflected signals are then processed to reconstruct the reflectors in the scene, wherein the processing enforces a model that a reflectivity of the scene in front and behind any reflector is equal to zero. The n DFE circuits are configured to equalize the n respective sampling signals in response to a DFE control signal and generate n respective pre-recovery signals in response to the n equalized sampling signals and n respective previous pre-recovery signals, the DFE control signal for changing an equalization ability of the n DFE circuits. Subject to non-contact sensing design, the control device avoids any mechanical fatigue or contact failure.