Image forming apparatus

An image forming apparatus comprising:

• a stack portion on which recording materials are to be stacked;
• a feeding unit configured to feed each of the recording materials stacked on the stack portion;
• an image forming unit configured to form an image on each recording material of the recording materials fed by the feeding unit;
• a transmitter configured to transmit an ultrasonic wave;
• a receiver configured to receive the ultrasonic wave transmitted from the transmitter via the recording material and an operating sound generated in the image forming apparatus;
• a basis weight detection unit configured to detect a value corresponding to a basis weight of the recording material based on the ultrasonic wave received by the receiver;
• an operating sound detection unit configured to detect an abnormality based on the operating sound received by the receiver;
• and
• a mode selection unit configured to select, for each of the recording materials fed to the image forming unit, between a first mode in which the basis weight detection unit detects the value and a second mode in which the operating sound detection unit detects the abnormality,
• wherein the mode selection unit selects the second mode for a first recording material, a second recording material, and a third recording material fed from the feeding unit,
• wherein the mode selection unit performs the first mode for at least one or more recording materials fed between the first recording material and the second recording material and for at least one or more recording materials fed between the second recording material and the third recording material, and
• wherein a number of the at least one or more recording materials fed between the first recording material and the second recording material is different from a number of the at least one or more recording materials fed between the second recording material and the third recording material.