An image forming apparatus includes image bearers including a first image bearer and a second image bearer and circuitry that corrects misalignment of images developed on the image bearers, transferred to a transfer member, and detected by a detector. The circuitry sequentially executes a first correction process and a second correction process. The first correction process includes correcting misalignment in relation to images developed on the first image bearer based on images developed on a first group of image bearers of the image bearers. The first group of image bearers includes the first image bearer and the second image bearer. The second correction process includes correcting misalignment in relation to images developed on the second image bearer based on images developed on a second group of image bearers of the image bearers. The second group of image bearers excludes the first image bearer and includes the second image bearer.

An image forming apparatus includes an image bearing member, a voltage applying portion, a feeding portion, a detecting portion, a storing portion, a controller for controlling a first operation in which on the basis of a detection result of the detecting portion, a kind of the recording material set in the feeding portion is stored in the storing portion, and a second operation in which an adjusting chart is outputted for adjusting a transfer voltage; and an inputting portion. In response to a single start instruction, the controller is capable of carrying out control so as to execute the first operation and the second operation for outputting the adjusting chart prepared by transferring a plurality of test images onto the recording material from which an index interrelating with the kind of the recording material is detected by the detecting portion in the first operation.

An example image forming apparatus includes a printing portion to print an image on a print medium, a gate member at an outgoing side of the printing portion to selectively guide the print medium discharged from the printing portion to a first route or a second route, and a reading member in the first route to read the image from the print medium discharged from the printing portion.

An image forming apparatus includes an image forming portion, an exposure device, an image density sensor, and a control portion. The control portion can, by adjusting the development voltage based on the image density of a reference image and the amount of exposure from the exposure device, perform image density correction to adjust the image density. The control portion predicts the toner charge amount based on a formation condition of the reference image and the image density of the reference image and determines the timing of performing the image density correction next time based on the rate of change of the toner charge amount calculated using a first toner charge amount predicted when the image density correction was performed last time, a second toner charge amount predicted when the image density correction is performed this time, and the interval between the image density correction performed last time and this time.

An image forming apparatus includes: a control unit configured to form, onto an image carrier, a detection pattern including a first image group including a plurality of first images and a second image group including a plurality of second images, and determine a color misregistration amount in a rotational direction and a width direction orthogonal to the rotational direction based on a detection result of the detection pattern. The detection pattern includes a plurality of basic patterns arranged at a first interval in the rotational direction, and each of the plurality of basic patterns includes the first image group and the second image group arranged at a second interval in the rotational direction, and the first image group and the second image group arranged at a third interval different from the second interval in the rotational direction.

A test image is formed by an image forming unit. A sensor receives light reflected from a test image on an intermediate transfer member passing through a detection position and outputs an output signal based on a reception result of the reflected light. A controller reduces density unevenness of images to be formed in a rotation direction of a photosensitive member based on a correction data, determines a reference output signal used to generate the correction data among output signals output from the sensor in time series based on a timing at which the test image reaches the detection position.

A control device selects one of a plurality of chromatic colors as a target chromatic color according to a consumption status of developing agents of the plurality of chromatic colors. The control device causes an image forming portion to execute a process of forming, on a surface of a transfer medium, a plurality of chromatic color test images of the plurality of chromatic colors, and a superimposed test image in which a black test image is superimposed on a background image of the target chromatic color. The control device acquires a test detection signal of an amount of diffuse reflection light in each of areas of the plurality of chromatic color test images and the superimposed test image on the surface of the transfer medium. The control device adjusts timing of image formation of the plurality of colors by the image forming portion based on the test detection signal.

An image forming apparatus includes an image carrying member, a charging device, an exposure device, a developing device, a toner container, a toner concentration sensor, a toner charge amount detection portion, and a control portion. The developing device includes a developer carrying member carrying a two-component developer and develops an electrostatic latent image into a toner image. The toner concentration sensor detects a toner concentration in the developing device. The toner charge amount detection portion detects a toner charge amount in the developing device. Based on a result of detection by the toner concentration sensor, the control portion controls replenishment of the developing device with the toner from the toner container. Based on the toner charge amount detected by the toner charge amount detection portion, the control portion executes first target value changing control of changing a target value of the toner concentration.

An image forming apparatus includes an image carrying member, a charging device, an exposure device, a developing device, an intermediate transfer belt, a cleaning brush, an image density sensor, and a control portion. The control portion executes calibration including: a first adjustment process of changing an image forming condition based on a result of detection of a first reference image formed on the intermediate transfer belt; a first bare-surface-measurement process of detecting, after execution of the first adjustment process, a first-reference-image formation area; and a second adjustment process of changing, after execution of the first bare-surface-measurement process, the image forming condition based on a result of detection of a second reference image formed on the first-reference-image formation area. In a case where an output value of the image density sensor in the first bare-surface-measurement process is equal to or less than a threshold value, the second adjustment process is executed.

An image forming apparatus includes an image forming section, an intermediate transfer belt, and a stretching roller. The intermediate transfer belt has a pair of test regions on opposite sides of a printing region in the width direction, and the image forming section transfers a test pattern image to the test regions. The image forming apparatus further includes an image density sensor and a counter-sensor member having a counter portion facing the image density sensor across the intermediate transfer belt. The edge positions of the counter portion in the width direction are inward, in the width direction, of the edge positions of the stretching roller in the width direction.