Cleaning sheet for use in an image forming apparatus and cleaning method

An image forming apparatus comprising:

• a transport unit configured to transport a printing medium;
• an input unit configured to input the printing medium transported by the transport unit as a first printing medium having an adhering matter;
• a printing unit configured to form an image on the printing medium;
• a fixing unit configured to heat and press the printing medium at a fixing temperature to fix the image;
• and
• a control unit configured as:
• a first counter configured to count a first number of sheets of the first printing medium transported by the transport unit,
• a second counter configured to count a second number of sheets of the printing medium including the first printing medium transported by the transport unit, and
• to execute a cleaning operation when a first value of a counter is more than a threshold value set in advance,
• wherein in the cleaning operation, the second counter is not increased, and the printing unit is stopped, and
• a second printing medium, other than the first printing medium, that is transported by the transport unit is passed through the fixing unit.