Image forming apparatus, monitoring system for image forming apparatus, and operation program for image forming apparatus

A monitoring system for an image forming apparatus, comprising:

• an image forming apparatus including:
• a communication unit;
• an image forming section configured to form an image on a sheet on the basis of print data the communication unit received;
• and
• a controller configured to switch a security level between a first state and a second state, the first state allowing printing by the image forming section of only first print data provided with verification information among print data the communication unit received, and the second state allowing printing by the image forming section of print data the communication unit received irrespective of presence or absence of verification information, the controller switching the security level from the first state to the second state when, in the first state, the controller receives a permission signal that instructs permission of printing of second print data not provided with verification information, so as to allow printing of the second print data by the image forming section, and switching the security level from the second state to the first state after allowing the printing of the second print data;
• and
• a monitoring device that transmits the permission signal to the communication unit.