Status determination and control of toner cartridge using sensor

A non-transitory computer-readable storage medium having stored therein instructions executable by a processor, the instructions comprising:

• instructions for obtaining, from a sensor, an output signal corresponding to a degree of shrinkage of a transporting member that transports a developing agent in a toner cartridge, as the transporting member rotates;
• instructions for determining a state of the toner cartridge based on a characteristic of the output signal;
• and
• instructions for executing a recovery mode that increases a driving force delivered to the transporting member when it is determined that the state of the toner cartridge is an abnormal state in which toner is not normally supplied to a developing device.

An image forming apparatus comprising:

• a toner cartridge;
• a sensor to obtain an output signal corresponding to a degree of shrinkage of a transporting member that transports a developing agent in a toner cartridge as the transporting member rotates;
• a developing device supplied with toner in the developing agent from the toner cartridge;
• a user interface device;
• a processor;
• and
• a memory storing instructions executable by the processor,
• wherein the processor executes the instructions to:
• determine a state of the toner cartridge based on a characteristic of the output signal;
• and
• execute a recovery mode that increases a driving force delivered to the transporting member when determining that the state of the toner cartridge is an abnormal state in which toner is not normally supplied to the developing device.