Paper reading apparatus, jam detection method, and computer-readable, non-transitory medium

A jam detection method in a paper reading apparatus for reading an image from a paper, the method comprising:

• acquiring a component of a first frequency band of an ultrasonic wave transmitted by an ultrasonic transmitter and passing through the paper, and a component of a second frequency band which is within the audible range and lower than the first frequency band of a sound of conveyance at the time of paper conveyance, from a filter for separating the component of the first frequency band and the component of the second frequency band, wherein the ultrasonic transmitter is provided near a conveyance path of the paper and the ultrasonic receiver is provided opposed to the ultrasonic transmitter across the conveyance path;
• determining whether multifeed of papers has occurred based on the component of the first frequency band;
• determining whether a jam has occurred based on the component of the second frequency band;
• and
• performing, by a computer, an abnormal processing based on the determining whether a jam has occurred,
• wherein the computer determines that the jam has not occurred and does not perform the abnormal processing, when determining that the jam has occurred and determining that the multifeed has occurred.

A computer-readable, non-transitory medium storing a computer program, wherein the computer program causes a paper reading apparatus for reading an image from a paper to execute a process, the process comprising:

• acquiring a component of a first frequency band of an ultrasonic wave transmitted by an ultrasonic transmitter and passing through the paper, and a component of a second frequency band which is within the audible range and lower than the first frequency band of a sound of conveyance at the time of paper conveyance, from a filter for separating the component of the first frequency band and the component of the second frequency band, wherein the ultrasonic transmitter is provided near a conveyance path of the paper and the ultrasonic receiver is provided opposed to the ultrasonic transmitter across the conveyance path;
• determining whether multifeed of papers has occurred based on the component of the first frequency band;
• determining whether a jam has occurred based on the component of the second frequency band;
• and
• performing an abnormal processing based on the determining whether a jam has occurred,
• wherein the computer determines that the jam has not occurred and does not perform the abnormal processing, when determining that the jam has occurred and determining that the multifeed has occurred.