Patent ID: 8651611

Claim:
An ink jet recording apparatus that ejects droplets from nozzles of an ink jet head to record an image on a cut sheet-shaped recording medium, comprising: a processing barrel that performs predetermined processing on the recording medium while rotating with the recording medium retained on an outer circumferential surface thereof; a transfer barrel that is disposed on an upstream side or a downstream side in a conveying direction of the recording medium with respect to the processing barrel so as to retain the recording medium on an outer surface thereof and transfer or receive the recording medium to or from the processing barrel by rotating with a leading end of the recording medium grasped; a conveying unit that is disposed on the opposite side of the transfer barrel in the conveying direction of the recording medium with respect to the processing barrel so as to convey the recording medium from or to the processing barrel; a first detection sensor and a second detection sensor that are provided so as to face the transfer barrel and the conveying unit to detect a pass of the recording medium; and an abnormal pass detecting circuit that receives a first output signal output from the first detection sensor and a second output signal output from the second detection sensor so as to detect an abnormal pass of the recording medium from the received first and second output signals, wherein the abnormal pass detecting circuit includes a first reverse logic delay timer that delays timing of a logic reverse to a detection logic of the first detection sensor with respect to the first output signal, and a second reverse logic delay timer that delays timing of a logic reverse to a detection logic of the second detection sensor with respect to the second output signal, and wherein signal changes shorter than timer setting periods of the first and second reverse logic delay timers are removed from the first and second output signals, respectively, to thereby prevent detection errors of the abnormal pass of the recording medium by the abnormal pass detecting circuit.