Certain embodiments provide an image forming apparatus including: a transmission and reception part to receive printing data and a scheduled number of copies of printing by a USB command from a computer apparatus; a sensor to detect occurrence and removal of an error; a printing part to print the printing data; a storage part to store the number of printed sheets and the scheduled number of copies; a calculation part to calculate a remaining number of copies to be printed based on the number of printed sheets and the scheduled number of copies; and a control part to control the transmission and reception part to transmit the remaining number of copies to the computer apparatus, receive a resumption number of copies having substantially the same value as the remaining number of copies from the computer apparatus after return, and register the resumption number of copies.