Image forming apparatus and image forming method

An image forming apparatus, comprising:

• a photosensitive drum;
• a developing roller configured to develop an electrostatic latent image on the photosensitive drum with a toner to form a toner image;
• a belt onto which the toner image formed on the photosensitive drum is to be transferred or on which a recording material, onto which the toner image is to be transferred, is borne;
• a detector configured to detect a density of a detection image formed on the belt;
• a controller configured to perform a first detection image actual measurement for obtaining a first characteristic indicating a relationship between input image data in a first mode and a density corresponding to the input image data based on a result of detecting the density of the detection image by the detector in the first mode;
• and
• a storage,
• wherein the controller is configured to perform a predicted density correction for predicting, based on the first characteristic, a characteristic indicating a relationship between input image data in a second mode in which an image formation is performed with a color gamut different from a color gamut in the first mode and the density corresponding to the input image data, and perform an image formation in the second mode by using a predicted characteristic,
• wherein the controller is configured to perform a second detection image actual measurement for obtaining a second characteristic indicating a relationship between the input image data in the second mode and the density corresponding to the input image data based on a result of detecting the density of the detection image by the detector in the second mode, obtain a correction value based on the second characteristic and the predicted characteristic, and correct the predicted characteristic by using an obtained correction value while storing the obtained correction value in the storage, and
• wherein the controller is configured to further correct the predicted characteristic by using the obtained correction value stored in the storage without performing the second detection image actual measurement.

An image forming method to be performed by an image forming apparatus, the image forming apparatus comprising a photosensitive drum, a developing roller configured to develop an electrostatic latent image on the photosensitive drum with a toner to form a toner image, a belt onto which the toner image formed on the photosensitive drum is to be transferred or on which a recording material, onto which the toner image is to be transferred, is borne, a detector configured to detect a density of a detection image formed on the belt, wherein the image forming apparatus is configured to perform an image formation in a first mode in which a circumferential speed difference of a circumferential speed of the developing roller with respect to a circumferential speed of the photosensitive drum is a first circumferential speed difference and in a second mode in which the circumferential speed difference is greater than the first circumferential speed difference, a controller configured to calculate a first conversion unit configured to convert a gradation of input image data so that a density output for the input image data becomes a first density output characteristic based on a first detection result of the detection image detected by the detector in the first mode, and a storage, the image forming method comprising:

• generating, by the controller, a second conversion unit configured to convert the gradation of the input image data so that the density output for the input image data becomes a second density output characteristic in the second mode based on the detection result in the first mode and correction information;
• and
• further updating, by the controller, the correction information based on a second detection result of the detection image detected by the detector in the second mode and the first detection result.

An image forming method to be performed by an image forming apparatus, the image forming apparatus comprising a photosensitive drum, a developing roller configured to develop an electrostatic latent image on the photosensitive drum with a toner to form a toner image, a belt onto which the toner image formed on the photosensitive drum is to be transferred or on which a recording material, onto which the toner image is to be transferred, is borne, a detector configured to detect a density of a detection image formed on the belt, a controller configured to perform a first detection image actual measurement for obtaining a first characteristic indicating a relationship between input image data in a first mode and a density corresponding to the input image data based on a result of detecting the density of the detection image by the detector in the first mode, and a storage, the image forming method comprising:

• performing, by the controller, a predicted density correction for predicting, based on the first characteristic, a characteristic indicating a relationship between input image data in a second mode in which an image formation is performed with a color gamut different from a color gamut in the first mode and the density corresponding to the input image data, and performing an image formation in the second mode by using a predicted characteristic;
• performing, by the controller, a second detection image actual measurement for obtaining a second characteristic indicating a relationship between the input image data in the second mode and the density corresponding to the input image data based on a result of detecting the density of the detection image by the detector in the second mode, obtaining a correction value based on the second characteristic and the predicted characteristic, correcting the predicted characteristic by using an obtained correction value while storing the obtained correction value in the storage;
• and
• further correcting, by the controller, the predicted characteristic by using the obtained correction value stored in the storage without performing the second detection image actual measurement.