An image forming apparatus includes a plurality of image bearers, a plurality of rotation reference position detectors, and circuitry. Each of the plurality of rotation reference position detectors faces a corresponding image bearer of the plurality of image bearers to detect a rotation reference position of the corresponding image bearer. The circuitry performs, before an operation of rotating the plurality of image bearers, alignment control based on a result of detection performed by the plurality of rotation reference position detectors. The alignment control is control of driving of the plurality of image bearers to acquire a given relationship between the respective rotation reference positions of the plurality of image bearers. The circuitry determines whether to perform the alignment control based on whether the operation of rotating the plurality of image bearers is a function maintenance related operation.

An image formation apparatus according to an embodiment may include: a first image formation section configured to form a first image of a developer containing a lustrous pigment; a second image formation section configured to form a second image of a dyeing developer; and a transfer section configured to transfer the first image and the second image on a medium such that the first image and the second image are stacked to each other on the medium.

An image forming apparatus forms a color image on a recording medium by superimposing images of colors formed by image forming units. The apparatus includes a processor that: acquires a read image by reading the recording medium on which the color image has been formed; forms a register patch outside a job image forming region of the recording medium; and corrects image forming positions of the image forming units based on the read image that includes the register patch. The register patch includes: a leading end patch and a rear end patch formed with a reference color material; and one or more measurement target color patches formed with measurement target color materials between the leading end patch and the rear end patch. The hardware processor corrects the image forming positions based on relative positions of the leading end patch, the rear end patch, and the measurement target color patches.

An image forming apparatus includes plural image forming units and a controller. The plural image forming units are configured to form images of colors using colorants, respectively. The controller is configured to perform control such that the plural images formed by the plural image forming units are output as one image onto a recording medium. At least two of the image forming units are configured to form images using colorants of special colors, respectively and are arranged in succession.

An image formation apparatus includes: an image former that prints an image on paper; a corrector that corrects a print position of the image on the paper; and a first sensor that is disposed on a conveyance path upstream of the image former, detects paper, and outputs detection data to the corrector, wherein the corrector obtains, on the basis of the detection data, an amount of change in a shape of first paper from a shape of second paper printed before the first paper is printed, and corrects a print position of a first image on the first paper on the basis of the change amount.

A control circuit executes voltage adjustment processing of adjusting a voltage output from a transfer power source so that a current detected by a detection circuit becomes a predetermined current value. The voltage adjustment processing is executed before a toner image is transferred from at least one of a first image bearing member and a second image bearing member to an intermediate transfer belt. A processor determines whether the second transfer member is in a state of contact or is in a state of separation on the basis of behavior of the current detected by the detection circuit in a period in which the control circuit is executing the voltage adjustment processing.

An image forming apparatus includes: an apparatus body; an image forming unit that forms a toner image on a recording medium; a first transport part that transports the recording medium to the image forming unit along a feed path extending from one side toward the other side in the horizontal direction, the feed path being a path along which the recording medium transported by the first transport part passes, and that includes a portion extending toward the one side beyond the image forming unit; and a second transport part that transports the recording medium from the image forming unit to the outside of the apparatus body along a discharge path extending from the other side toward one side in the horizontal direction and that includes a portion extending toward the one side beyond the image forming unit, the discharge path and the feed path at least partially overlapping each other in the vertical direction.

An image forming apparatus is capable of being attached with a toner supply container. The toner supply container stores a toner that is to be supplied to a developing portion. An attachment location of the toner supply container is below a light scanning portion in a vertical direction.

An image forming apparatus includes: an annular formation target body to be transported; a change roller that is in contact with an inner peripheral surface of the formation target body so as to be rotatable around a rotation axis and that is capable of changing an angle of the rotation axis with respect to a width direction of the formation target body; multiple first image forming bodies that are arranged at a first distance from each other along the formation target body on an upstream side of the change roller in a transport direction of the formation target body, and that form images on the formation target body; and multiple second image forming bodies that are arranged at a second distance smaller than the first distance from each other along the formation target body on a downstream side of the change roller in the transport direction of the formation target body, and that form images on the formation target body.

An image forming apparatus includes image forming units. A controller includes an execution section, a measurement section, and a prediction section. The execution section controls execution of a developer refresh operation in which toner is ejected from a developer bearing member to an image bearing member so that a specific image forming unit replenishes a development device with the toner from the developer bearing member. The measurement section measures respective surface potentials of the image bearing members included in other image forming units while the specific image forming unit is executing the developer refresh operation. The prediction section uses measurement results of the respective surface potentials of the image bearing members included in the other image forming units for a prediction on the surface potential of the image bearing member included in the specific image forming unit.