Image fixing apparatus and image forming apparatus capable of effectively controlling an image fixing temperature

An image forming apparatus in electrophotographic process, comprising:

• an image fixing apparatus that fixes a toner image onto an recording medium including:
• a pair of rotating members to form a nip-press region through which the recording medium passes,
• a heater to heat at least one of the pair of rotating members,
• a temperature sensor to detect a temperature of the at least one of the pair of rotating members,
• a calculator to calculate a heat value to increase a temperature of the at least one of the pair of rotating members to a target temperature based on a temperature detected by the temperature sensor,
• a controller to control the heater based on a calculation result of the heat value output by the calculator,
• a compensator to calculate and generate a delay compensation output by using a delay prediction model according to the calculation result of the calculator, and
• a selector to select one of a first condition in which the delay compensation output is entered into an input of the calculator and a second condition in which the delay compensation output is not entered into the input of the calculator, wherein the selector selects the first condition when continuously performing an image fixing operation on a plurality of the recording mediums continuously fed.

An image fixing apparatus which fixes a toner image onto a recording medium, comprising:

• means for forming a nip-press region through which the recording medium passes;
• means for heating the nip-press region;
• means for detecting a temperature of the means for forming;
• means for calculating a heat value to increase a temperature of the means for heating to a target temperature based on a temperature detected by the means for detecting;
• means for controlling the means for heating based on a calculation result of the heat value output by the means for calculating;
• means for compensating by calculating and generating a delay compensation output by using a delay prediction model according to the calculation result of the means for calculating;
• and
• means for selecting one of a first condition in which the delay compensation output is entered into an input of the means for calculating and a second condition in which the delay compensation output is not entered into the input of the means for calculating, wherein the means for selecting selects the first condition when continuously performing an image fixing operation on a plurality of the recording mediums continuously fed.