Image forming apparatus capable of timely starting different image formation mode

An image forming apparatus comprising:

• an image formation device to form a toner image to be transferred and fused later onto a recording medium under at least two prescribed different image formation conditions;
• a thermal fixing unit including a fixing member heated or cooled to at least two prescribed first and second target fixing temperatures, said second target fixing temperature being lower than the first target fixing temperature and a pressing member pressing against the fixing member to form a fixing nip thereat, said thermal fixing unit fixing the toner image onto a recording medium by conveying the recording medium through the fixing nip;
• and
• a controller to permit the image formation device to start image formation all of when the first target fixing temperature is changed to the second target fixing temperature, and when a previous job is completed under a previous image formation condition designated previously and the next job becomes available, and when a prescribed elapsing time has elapsed after the next job becomes available, said prescribed time being determined in accordance with a type of an image to be outputted.