Mobile device that ensures function extension of image forming apparatus, image forming system, and recording medium

A non-transitory computer-readable recording medium storing a function extension program for extending a function of an image forming apparatus, the function extension program causing a mobile device including an operation circuit and a display to function as:

• an operation screen display that displays an operation screen to operate the image forming apparatus on the display;
• and
• a function execution circuit that performs a function other than a function executable by the image forming apparatus alone and a specified function performed using the image forming apparatus,
• wherein the function execution circuit performs the specific function according to an operation to an operation part in the operation screen displayed on the display via the operation circuit.

A method for extending a function of an image forming apparatus using a mobile device including an operation circuit and a display, the method including:

• displaying an operation screen to operate the image forming apparatus on the display;
• and
• performing a function other than a function executable by the image forming apparatus alone and a specified function performed using the image forming apparatus,
• wherein the executing performs the specific function according to an operation to an operation part in the operation screen displayed on the display via the operation circuit.