Image forming apparatus

An image forming apparatus comprising:

• an image forming unit configured to form a toner image on a recording material;
• a fixing unit configured to heat and fix the toner image formed on the recording material to the recording material in a fixing nip portion, wherein the fixing unit includes a heater and a nip portion forming member that forms the fixing nip portion to pinch and convey the recording material;
• and
• a control unit configured to control power to be supplied to the heater,
• wherein the control unit is configured to control the power to be supplied to the heater so as to change a temperature gradient at time of warm-up of the fixing unit to a target temperature in accordance with time from start of power supply to the heater until entry of the recording material into the fixing nip portion.