An image forming apparatus includes an image carrier, an image forming unit, an intermediate transfer belt, a power supply, a transfer member to transfer toner image on the intermediate transfer belt to a recording medium, and a sensor to detect, as density information, a density of the recording medium toner image. In an adjustment mode, (i) a test recording medium is output as a test chart by applying multiple levels of test voltages to the transfer member to transfer test toner images to the test recording medium, (ii) the transferred test toner images are detected via the sensor, and (iii) a transfer voltage is adjusted based on the sensor detection. In the adjustment mode, test toner image groups are set, one test toner image group is extracted based on an index value, and the transfer voltage is adjusted based on the density information of the extracted test toner image group.

A first test image has one line segment of a first color and another line segment of the first color. The second test image has one line segment of the first color and another line segment of a second color or has one segment of the second color or another segment of the first color. The third test image has one line segment of the second color and another line segment of the second color. The fourth test image has one line segment of the second color and another line segment of a third color or has one segment of the third color or another segment of the second color. The fifth test image has one line segment of the third color and another line segment of the third color. An apparatus obtains an amount of color misregistration based on the test images.

A color printing system includes a color management service and one or more printing devices. An ink limit is specified for a calibration operation that uses a calibration chart to obtain measurement data. Using the measurement data, a calibration tone reproduction curve (TRC) along with calibration settings is generated. The calibration TRC and the ink limit are stored. For a print job, the calibration is identified and used to retrieve the calibration TRC and the ink limit. The original ICC profile for the calibration TRC also is provided. The ink limit is used to adjust the ICC profile accordingly. The adjusted ICC profile is used for color printing one or more documents for a print job.

An image forming apparatus includes an image forming portion, an image bearing member, a transfer member, a voltage source, a density detecting portion, a display portion, a controller, and an operating portion. The controller is capable of executing an operation in a mode in which a test chart for adjusting a transfer voltage is outputted, and setting information on the transfer voltage set for during transfer on the basis of a detection result when the test chart is detected by the detecting portion is displayed at the display portion and is checked by user. The controller causes the display portion to display setting information on the basis of a correcting value and causes the user to check the setting information in the operation in the mode executed after the correcting value is inputted from the operating portion.

An imaging system includes a transfer roller, a bias application device, and a controller. The transfer roller forms a transfer nip region between the transfer roller and a transfer belt, and the transfer roller transfers toner images carried on the transfer belt, onto media conveyed through the transfer nip region, during a print job. The bias application device applies a bias to the transfer roller. The controller controls the bias application device to apply a first bias to the transfer roller so that the toner image is transferred to a first medium during the printing job, apply a second bias having a polarity opposite to the first bias to the transfer roller between the first medium and a second medium following the first medium, and apply a third bias having the same polarity as the first bias to the transfer roller between the first medium and the second medium.

An image forming apparatus superimposes a plurality of color images each formed of a single-color developer to form a superimposed color image. The image forming apparatus includes a transfer belt and processing circuitry. The processing circuitry forms, as a correction pattern, combination patterns arranged along a conveyance direction of the color images and including a first pattern, a second pattern, and a third pattern. A formation interval of the first pattern constituting one combination pattern is shorter than a formation interval between one horizontal line of the first pattern constituting the one combination pattern and another horizontal line of the first pattern constituting another combination pattern. The one horizontal line is opposite the other horizontal line.

An image forming apparatus includes an image carrier, an image forming unit, a transfer unit, a detector, a controller, an edge detector, and an abnormality detector. The detector detects developer attached to an image carrying surface at a position between a position where an image is formed and a position where the image is transferred. The controller controls the image forming unit such that a check image including an edge that extends in a direction intersecting the moving direction of the image carrying surface is formed in a region of the image carrying surface that passes through the detection position. The edge detector determines a position of the edge based on a detection status of the developer. The abnormality detector determines whether or not the image former is abnormal based on the position of the edge.

An image forming apparatus includes a detecting unit configured to detect a test image formed on an image carrier; and an obtaining unit configured to obtain a color misregistration amount using a detection result of the test image by the detecting unit. The test image includes one or more basic patterns; each one of the one or more basic patterns includes a first pattern group and a second pattern group disposed at different positions with respect to a conveyance direction of the image carrier; the first pattern group and the second pattern group each include a plurality of V-shaped patterns; and the V-shaped patterns of the first pattern group and the second pattern group have an axisymmetrical shape about an axis corresponding to a width direction orthogonal to the conveyance direction.

An image forming apparatus includes a sheet transport path that transports a sheet on which an image has been recorded, the sheet transport path including a first guide surface and a second guide surface opposed to the first guide surface, an image reading unit disposed on the same side as the first guide surface of the sheet transport path to read the image, and a rotary element disposed on the same side as the second guide surface, the rotary element being rotatably disposed with a gap between the rotary element and the first guide surface.

An example photodetector for detecting fluorescent toner includes a light emitting unit to emit light to a toner image, and a light receiving unit. The light receiving unit is to detect visible light reflected by the toner image, detect that the toner image includes the fluorescent toner based on the detection of the visible light, the visible light generated by the fluorescent toner and having a predetermined wavelength band different from a wavelength band of the emitted light, and output a signal corresponding to the detection of the fluorescent toner.