In an example, a method includes printing a set of images by transferring print agent between a roller of a print agent source and an electrophotographic surface in a plurality of transfer operations, wherein the roller is controlled to have a first voltage profile during each of the transfer operations. A variation in optical density which is consistent across the set of printed images may be detected, and a second voltage profile correction may be determined based on the variation in optical density. The method may further comprise printing a subsequent image by transferring print agent between the print agent source roller and the electrophotographic surface in a subsequent transfer operation, wherein the roller is controlled to have the second voltage profile during the subsequent transfer operation.

An image forming apparatus includes an image forming unit (LBP) to form an image on a sheet, a conveyance unit configured to convey the sheet, a sensor, which is configured to move in a direction perpendicular to a conveying direction in which the conveyance unit conveys the sheet, and to read the image on the sheet, and a controller. The image forming unit forms a first trigger image and a first pattern image on the sheet, and the image forming unit forms a second trigger image and a second pattern image at a position on the sheet different from a position of both the first trigger image and the first pattern image in the conveying direction. A formation area of the first trigger image in the direction perpendicular to the conveying direction overlaps with a formation area of the second pattern image.

A detecting apparatus includes: a light emitting element which emits light toward a detection material; a light receiving element which receives reflected light from the detection material; and an apparatus main body having an opening/closing member which opens and closes an opening through which light emitted from the light emitting element and reflected light from the detection material pass through, the apparatus main body being capable of moving between a first position where the apparatus main body comes into contact with the detection material and a second position where the apparatus main body separates from the detection material, and the opening/closing member being configured to open when the apparatus main body moves to the first position and to close when the apparatus main body moves to the second position.

First correction data for use in a first printing mode is generated by image density measurement in the first printing mode, and second correction data for use in a second printing mode, which is different from the first printing mode in peripheral speed ratio of a developing roller to a photosensitive drum, is generated by image density measurement in the second printing mode. First processing for generating first and second correction data for the first and second printing modes, respectively, by density measurement, or second processing for generating the first correction data by density measurement and generating the second correction data using the generated first correction data and a difference in image density between the first printing mode and the second printing mode is executed. The first processing is executed when a predetermined condition is satisfied.

A measurement apparatus includes a first conveyance path, a second conveyance path, a measuring portion, a third conveyance path and a sheet stacking portion. A sheet discharged out of an image forming apparatus is conveyed toward a downstream apparatus through the first conveyance path. The second conveyance path is branched from the first conveyance path, extended below the first conveyance path, and merged with the first conveyance path. The measuring portion is disposed on the second conveyance path. The third conveyance path is provided above the first conveyance path and is configured to convey the sheet from which a test image has been measured by the measuring portion in the second conveyance path. The sheet stacking portion is provided above the first conveyance path, and the sheet discharged out of the third conveyance path is stacked on the sheet stacking portion.

An image forming apparatus includes a temperature sensor, a memory, a fixing device, and a controller. The temperature sensor is configured to detect a temperature of an inside of the image forming apparatus. The memory is configured to store temperature history information regarding a history of the temperature of the inside of the image forming apparatus detected by the temperature sensor. The fixing device is configured to fix a toner image onto the paper sheet by heating the paper sheet to a fixing temperature. The toner image is transferred to the paper sheet using a toner stored in a toner cartridge of the image forming apparatus. The controller is configured to control a fixing temperature at the fixing device based on the temperature history information stored in the memory.

An image forming apparatus, configured to operate in first and second modes of which color gamut is different from each other, includes an exposure unit configured to expose a photosensitive drum; a developing roller configured to form a toner image; a detection unit configured to detect density of the toner image transferred to an intermediate transfer member; and a controller configured to adjust the density based on a value of input image data. A dithering process for the controller's controlling of the exposure unit is different depending on whether the operation is in the first mode or the second mode, and in at least a part of the input image data, the density of the toner image formed by the dithering process in the first mode is higher than the density of the toner image formed by the dithering process in the second mode.

A controller controls a charging unit to charge a photosensitive member so that a surface potential of the photosensitive member is controlled to a first potential, controls an exposure unit to expose the photosensitive member so that a potential of an exposure region on the photosensitive member is controlled to a second potential, controls a surface potential of a developing sleeve of a developing unit to a third potential, and forms a test image on a sheet by controlling the photosensitive member, the charging unit, the exposure unit, and the developing unit. An absolute value of the first potential is higher than an absolute value of the second potential. An absolute value of the third potential is higher than the absolute value of the first potential.

An image forming apparatus includes an image forming unit configured to form an image on a sheet based on image forming condition, a reader configured to convey the sheet and read a test image on the sheet while the sheet is conveyed, and a controller configured to control the image forming unit to form the image and the test image on a same sheet, control the reader to read the test image on the same sheet, and generate the image forming condition for adjusting a density of an image to be formed by the image forming unit, based on a reading result of the test image by the reader.

An image forming apparatus includes: a job acquirer that acquires a print job; a photoconductor including a surface on which a toner image is to be formed; an electrifying member that electrifies the photoconductor; an exposure member that exposes the photoconductor; a developing member that supplies toner to the photoconductor; a cleaner that cleans the photoconductor; and a controller connected to the job acquirer to control the image forming apparatus, wherein the controller computes a first non-toner region that is provided on the surface of the photoconductor when the toner image is formed on the photoconductor, the first non-toner region not containing toner in a longitudinal direction of the surface of the photoconductor, and the controller causes the exposure member and the developing member to form the toner image on the photoconductor and to form a set of toner patches in the first non-toner region.