Image forming apparatus, image forming method, and computer readable recording medium for recording program that determines a fixing portion target temperature based on presence or absence of an image with a specific characteristic

An image forming apparatus, comprising:

• a fixing portion configured to fix a toner image formed in accordance with image data onto a recording material;
• a first determining portion configured to determine, based on the image data, presence or absence of a first image in which at least a first number of pixels each having a density-related value of at least a predetermined value are continuously arrayed in a subscanning direction which is a conveying direction of the recording material, and in which at least a second number of pixels each having a density-related value of at least the predetermined value are continuously arrayed in a main scanning direction which is orthogonal to the subscanning direction, the second number being greater than the first number;
• a second determining portion configured to determine a first temperature as a target temperature to maintain a temperature of the fixing portion regardless of a density-related value of the first image, in a case where a determination result by the first determining portion indicates the presence of the first image, or determine a second temperature as the target temperature to maintain the temperature of the fixing portion in a case where the determination result by the first determining portion indicates the absence of the first image, the second temperature being lower than the first temperature;
• 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,
• wherein a width of the first image in the subscanning direction is 120 to 380 μm, and
• a width of the first image in the main scanning direction is greater than 5 mm.

An image forming method of an image forming apparatus including a fixing portion configured to fix a toner image formed in accordance with image data onto a recording material, the image forming method comprising:

• executing, by a computer,
• a first determining step of determining, based on the image data, presence or absence of a first image in which at least a first number of pixels each having density-related value of at least a predetermined value are continuously arrayed in a subscanning direction which is a conveying direction of the recording material, and in which at least a second number of pixels each having the density-related value of at least the predetermined value are continuously arrayed in a main scanning direction which is orthogonal to the subscanning direction, the second number being greater than the first number;
• a second determining step of determining a target temperature at which to maintain a temperature of the fixing portion, wherein the target temperature is determined based on the presence of the first image regardless of a density-related value of the first image, in a case where a determination result in the first determining step indicates the presence of the first image, and wherein the target temperature is determined based on a density-related value of a second image that is different from the first image, in a case where the determination result in the first determining step indicates the absence of the first image;
• and
• a control step of controlling power to be supplied to the fixing portion so that the temperature of the fixing portion is maintained at the determined target temperature,
• wherein a width of the first image in the subscanning direction is 120 to 380 μm, and
• a width of the first image in the main scanning direction is greater than 5 mm.

An image forming method of an image forming apparatus including a fixing portion configured to fix a toner image formed in accordance with image data onto a recording material, the image forming method comprising:

• executing, by a computer,
• a first determining step of determining, based on the image data, presence or absence of a first image in which at least a first number of pixels each having a density-related value of at least a predetermined value are continuously arrayed in a subscanning direction which is a conveying direction of the recording material, and in which at least a second number of pixels each having a density-related value of at least the predetermined value are continuously arrayed in a main scanning direction which is orthogonal to the subscanning direction, the second number being greater than the first number;
• a second determining step of determining a first temperature as a target temperature to maintain a temperature of the fixing portion regardless of a density-related value of the first image, in a case where a determination result in the first determining step indicates the presence of the first image, or determining a second temperature as the target temperature to maintain the temperature of the fixing portion in a case where the determination result in the first determining step indicates the absence of the first image, the second temperature being lower than the first temperature;
• and
• a control 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 a width of the first image in the subscanning direction is 120 to 380 μm, and
• a width of the first image in the main scanning direction is greater than 5 mm.