Image forming apparatus and recording material discrimination unit

An image forming apparatus for forming an image on a recording material, the image forming apparatus comprising:

• a sensor configured to detect a characteristic of the recording material, and output an output value according to a detection result;
• and
• a processor configured to control an image forming condition based on the output value output by the sensor, and
• wherein, after the sensor detects a first recording material and outputs a first output value, the sensor detects a second recording material and outputs a second output value,
• wherein the processor obtains a differential value between the first output value and the second output value, the processor selects at least one of the first output value and the second output value based on the differential value, and the processor controls the image forming condition with respect to the second recording material based on the selected output value.