Image forming apparatus and image forming method

An image forming apparatus, comprising:

• a fixing portion configured to fix a toner image formed in accordance with image data to a recording material;
• a determining portion configured to acquire a density value indicating image density represented by the image data for each of colors of toners constituting the toner image, calculate a toner bearing amount for the each of the colors of the toners from the density values with respect to the respective colors of the toners, obtain a sum amount of the toner bearing amounts with respect to the respective colors of the toners, and determine a target temperature for maintaining a temperature of the fixing portion on the basis of the sum amount;
• and
• a control portion configured to control power to be supplied to the fixing portion so that the temperature of the fixing portion is maintained at the target temperature.

An image forming method, causing a computer included in an image forming apparatus to perform:

• a fixing step of fixing a toner image formed in accordance with image data to a recording material using a fixing portion;
• a determining step of acquiring a density value indicating image density represented by the image data for respective colors of toners constituting the toner image, obtaining a sum value of the density values with respect to the respective colors of the toners, obtaining a numerical value indicating the number of the density values being values larger than 0 out of the density values corresponding to the respective colors of the toners, and determining a target temperature for maintaining a temperature of the fixing portion on the basis of the sum value and the numerical value;
• and
• a controlling step of controlling power to be supplied to the fixing portion so that the temperature of the fixing portion is maintained at the target temperature, wherein
• the determining step includes, in a case the sum value is a first value and the numerical value is a first number, determining a first temperature as the target temperature, in a case the sum value is the first value and the numerical value is a second number that is larger than the first number, determining a second temperature that is lower than the first temperature as the target temperature.

An image forming method, causing a computer included in an image forming apparatus to perform:

• a fixing step of fixing a toner image formed in accordance with image data to a recording material using a fixing portion;
• a determining step of acquiring a density value indicating image density represented by the image data for respective colors of toners constituting the toner image, calculating a toner bearing amount for the respective colors of the toners from the density value with respect to the respective colors of the toners, obtaining a sum amount of the toner bearing amounts with respect to the respective colors of the toners, and determining a target temperature for maintaining a temperature of the fixing portion on the basis of the sum amount;
• and
• a controlling step of controlling power to be supplied to the fixing portion so that the temperature of the fixing portion is maintained at the target temperature.