An image forming apparatus includes: an image forming unit configured to form an image pattern on a medium, a predetermined image repeatedly appearing in a first cycle in a sub scanning direction in the image pattern; a density detector configured to optically detect a density of the image pattern in the sub scanning direction; a cyclic image detector configured to detect a feature image having a second cycle corresponding to the first cycle in accordance with a result of the detection; and a state determining unit configured to determine whether a cycle depending on an outer circumference of a rotary member included in the image forming apparatus corresponds to the second cycle when the feature image is detected by the cyclic image detector, and determine that a state of the rotary member has deteriorated when the cycle depending on the outer circumference is determined to correspond to the second cycle.

An image density detector for detecting image density of an image borne by an image bearer includes a reference board, a light emitter, a light receiver, an image density calculator, and an image density detecting condition corrector. The reference board has a spectral reflectance distribution closer to a spectral reflectance distribution of the image forming material than a spectral reflectance distribution of white. The light emitter emits light to the reference board and the image borne by the image bearer. The light receiver receives the light reflected from the image and the reference board. The image density calculator calculates the image density of the image based on an output of the light receiver receiving the light reflected from the image. The image density detecting condition corrector corrects an image density detecting condition based on an output of the light receiver receiving the light reflected from the reference board.

An image forming apparatus includes a first condition section that derives, from the density of the image detected by an image density detector, a forming condition in forming an image such that the density of the image formed comes close to a predetermined target density, a second condition section that derives, from the environmental state detected by the environmental detector, a forming condition such that the density of the formed image becomes the target density, and a stabilization section that causes, when a difference between the two forming conditions exceeds a predetermined degree, the image forming section to perform a stabilization operation which stabilizes a developing property of the developer in the developing device as compared to the current environmental state, and thereafter causes the formation of an image, the density detection, and the derivation of the forming condition by the first condition section to be performed again.

An image forming apparatus includes: a first image forming unit for forming toner images on a first photosensitive body; a second image forming unit for forming toner images on a second photosensitive body; a first exposure unit for exposing the first photosensitive body; a second exposure unit for exposing the second photosensitive body; a transfer unit for transferring, onto an intermediate transfer belt, toner images for correction formed from the first image forming unit and the second image forming unit; a detection unit for detecting the toner images for correction; and a control unit for controlling an exposure cycle of the first exposure unit, wherein the control unit corrects the exposure cycle of the first exposure unit based on a detected consequence of the detection unit.

A printer includes an image forming unit to form a toner image on an image receptor by using a toner containing fluorescent additives for generating light in a predefined wavelength band in response to light in an invisible wavelength band, transfer the toner image to a print medium, and fix the toner image on the print medium, a photodetector including a light emitting unit configured to irradiate light in an invisible wavelength band to the toner image accommodated in one of the image receptor and the print medium, and a light receiving unit to detect reflected light from the toner image, and a controller to control a printing operation of the image forming unit, based on a detection signal from the light receiving unit.

Changing of a peripheral speed ratio, resulting in change of the developer amount per unit area, enables the detection unit to detect the developer amount with sufficient accuracy.

An image forming apparatus comprises a plurality of image forming units, an intermediate transfer member, a detection unit, and a controller. The controller is configured to control the plurality of image forming units to form, on the intermediate transfer member, a pattern image including a first detection image having a reference color among the plurality of detection images and a second detection image having another color among the plurality of detection images. The first detection image and the second detection image are superimposed on a predetermined detection image. The controller is configured to control the detection unit to detect the amount of color misregistration which is related to a relative position of the first detection image and the second detection image, and to determine an adjustment value for adjusting an image write start timing of the other color different from the reference color.

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 includes: a toner transport body that is an endless belt holding a toner image, or is a transfer member transferring the toner image to a recording medium nipped between the endless belt and the transfer member; a cleaning brush that has plural first bristle materials that rotate and come into contact with a surface of the toner transport body, and cleans a toner adhering to the surface of the toner transport body; and a removing brush that has plural second bristle materials in contact with the first bristle material of the cleaning brush and removes the toner adhering to the first bristle material.

An electrophotographic image forming apparatus for forming an image in accordance with image information includes: an image forming unit configured to form an image that is uniform in area percentage of each of primary colors and a secondary color on an intermediate transfer belt; a measurer configured to measure amounts corresponding to density distribution of residual toner left on the intermediate transfer belt, on which the image uniform in area percentage of each of the primary colors and the secondary color is formed and from which toner is transferred onto a recording medium, in the main-scanning direction; and a corrector configured to correct a tone value of the image information so as to reduce density nonuniformity of a streak region observed in the density distribution in the main-scanning direction using the amounts measured by the measurer.