Image forming apparatus and control method thereof

A control method of an image forming apparatus which includes:

• a toner cartridge storing a toner;
• an image forming unit which forms a toner image with the toner supplied from the toner cartridge;
• and a counter which counts a consumption of the toner in the toner cartridge, the control method comprising:
• a detection step of detecting a density of a first toner image formed by the image forming unit;
• a judgment step of determining a necessity of a correction of a count value of the counter based on index information related to a status of the apparatus when the density of the first toner image is lower than a first density previously defined in correspondence to the first toner image and a quantity of the toner in the toner cartridge determined from the count value of the counter is smaller than a predetermined quantity;
• a correction step of correcting the count value of the counter when it is determined in the judgment step that the correction of the count value is necessary;
• a step of using a detected density of a second toner image as the index information, the second toner image formed by the image forming unit where an operation parameter affecting the image density is set to a different value from the value used in the formation of the first toner image;
• and
• a step of determining the correction of the count value to be necessary if a residual quantity of the toner in the toner cartridge indicated by the count value is smaller than a predetermined quantity and the second toner image has a higher density than a second predetermined density.

An image forming apparatus comprising:

• a toner cartridge storing a toner;
• an image forming unit that forms a toner image with the toner supplied from the toner cartridge;
• a counter that counts a consumption of the toner in the toner cartridge;
• and
• a controller that makes judgment on necessity of a correction of a count value counted by the counter when a density of a first toner image formed by the image forming unit is lower than a first density previously defined in correspondence to the first toner image based on a quantity of the toner in the toner cartridge indicated by the count value of the counter and index information that indicates a status of the apparatus, and that corrects the count value of the counter when determining the correction of the count value to be necessary,
• wherein the controller:
• uses detected densities of plural toner images as the index information, the plural toner images being formed by the image forming unit with operation parameters affecting the image density being set to different values from each other, and
• determines the correction of the count value to be necessary if a residual quantity of the toner in the toner cartridge indicated by the count value is smaller than a predetermined quantity and at least one of the plural toner images has a higher density than a predetermined value corresponding to a low image density to be practically ineffective.

A control method of an image forming apparatus that includes:

• a toner cartridge storing a toner;
• an image forming unit that forms a toner image with the toner supplied from the toner cartridge;
• and a counter that counts a consumption of the toner in the toner cartridge, the control method comprising:
• a detection step of detecting a density of a first toner image formed by the image forming unit;
• a judgment step of determining a necessity of a correction of a count value of the counter based on index information related to a status of the apparatus when the density of the first toner image is lower than a first density previously defined in correspondence to the first toner image and a quantity of the toner in the toner cartridge determined from the count value of the counter is smaller than a predetermined quantity;
• a correction step of correcting the count value of the counter when it is determined in the judgment step that the correction of the count value is necessary;
• a step of using detected densities of plural toner images as the index information, the plural toner images being formed by the image forming unit with operation parameters affecting the image density being set to different values from each other;
• and
• a step of determining the correction of the count value to be necessary if a residual quantity of the toner in the toner cartridge indicated by the count value is smaller than a predetermined quantity and at least one of the plural toner images has a higher density than a predetermined value corresponding to a low image density to be practically ineffective.