Image forming apparatus and control method of image forming apparatus with mode selection

A method of controlling an image forming apparatus including an image forming unit configured to form an image on a sheet by using toner, and a fixing device configured to heat the image to fix on the sheet, the method comprising:

• determining, by a control circuit, an instruction to change an operation mode to a first mode in which the image is formed using first toner or a second mode in which the image is formed using second toner;
• controlling, by the control circuit, heating of the fixing device to cause the fixing device to (i) perform heating to a first fixing reference temperature upon receiving a first image formation instruction in the first mode, (ii) perform heating to a second fixing reference temperature upon receiving a second image formation instruction in the second mode, the second fixing reference temperature being lower than the first fixing reference temperature, and (iii) perform heating to a first standby temperature upon receiving an instruction to change the operation mode a predetermined number of times before receiving a third image formation instruction in the second mode, the first standby temperature being between the first fixing reference temperature and the second fixing reference temperature;
• and
• controlling the fixing device to perform heating to a second standby temperature upon receiving an instruction to change the operation mode to the first mode from the second mode a predetermined number of times before receiving a fourth image formation instruction in the first mode, the second standby temperature being between the first fixing reference temperature and the second fixing reference temperature,
• wherein the first toner is non-decolorable toner, and the second toner is decolorable toner.