Fixing device and image forming apparatus including same

A fixing device for an image forming apparatus, comprising:

• a rotatable fixing member to rotate while contacting an unfixed image;
• a pressure member to press against the fixing member to form a fixing nip in cooperation with the fixing member;
• a power supply;
• a heating member divided into a plurality of heating elements in a direction perpendicular to a conveyance direction of a sheet of recording medium and to heat the fixing member with power from the power supply;
• a heat performance sensor to detect the heating performance of each heating element of the heating member;
• and
• a controller to control the heating member,
• wherein the image is fixed on the recording medium by passing the sheet of recording medium through the nip portion, and
• wherein the controller is configured to:
• control each heating element independently such that a temperature of a portion of the fixing member corresponding to a blank area on the recording medium becomes lower than the temperature of a portion of the fixing member corresponding to an image area on the recording medium;
• and
• control the temperature to be maintained at each heating element based on the detected heating performance of each heating element detected by the heat performance sensor.