An image forming apparatus includes a detector for detecting one of position and density information of a detection image based on a signal corresponding to a difference between a value of a detection signal corresponding to a first position of one of the detection image on an image carrier and a surface of the image carrier and an average value of a value of the detection signal corresponding to a second position on a downstream side with respect to the first position in a moving direction of the detection image and a value of the detection signal corresponding to a third position on an upstream side with respect to the first position in the moving direction during a time when the detection image formed on the image carrier passes through an irradiation region of an irradiation device.

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.

The image forming apparatus includes an image forming unit, a fixing unit having a heating member, a temperature detector, an acquisition unit, and a controller. When image formation is consecutively performed, and the acquisition unit acquires a first density, which is the density information of the image formed on a k-th recording material, and a second, higher density, which is the density information of the image formed on an l-th recording material, while the image is being fixed on the k-th recording material, the controller controls the power so that the detection temperature becomes a temperature higher than a fixing temperature according to the first density, and lower than a fixing temperature according to the second density. While the image is being fixed on the l-th recording material, the controller controls the power so that the detection temperature becomes the fixing temperature according to the second density.

An image forming apparatus including: a first processing unit configured to subject input image data to tone correction with use of a tone correction table; a second processing unit configured to subject the image data to dither processing; a correction unit configured to correct the image data with use of a correction amount based on positional deviation of scanning lines caused by a mirror face tangle error; a deflection unit configured to deflect light beams emitted from the light source with a mirror face to form the scanning lines; an extraction unit configured to extract a feature amount of the tone correction table; and an adjustment unit configured to adjust a change in tone characteristics in a case where the feature amount extracted by the extraction unit exceeds a predetermined range.

An image forming apparatus includes an image bearing member to which lubricant is supplied; a toner image forming section; and a patch image forming section and a control section configured to control the toner image forming section and the patch image forming section such that a first development condition for forming the patch image and a second development condition for forming the toner image are different from each other.

An image forming apparatus includes: a detection unit configured to detect a test pattern formed on an image carrier by image forming units; and an adjustment unit configured to control the image forming units to form the test pattern, and adjust relative positions of images based on a detection result of the test pattern. The adjustment unit is further configured to control the image forming units to form the test pattern after the image forming units has formed on the image carrier an image to be transferred to a sheet with a basis weight smaller than a threshold, and before the image forming units form on the image carrier an image to be transferred to a sheet with a basis weight larger than the threshold.

An image forming apparatus comprises an image forming unit configured to form measurement images used for density correction at different timing using pseudo halftone processing pattern and a density detection sensor for detecting density of an object to be detected on an optical path including the measurement image formed. Further, the image forming apparatus comprises a shutter which is arranged on the optical path between a density detection sensor and the measurement image, changed, by a motor, to a closed state in which a detecting surface of the density detection sensor is closed when the measurement image is not detected and changed to an open state in which the detecting surface of the density detection sensor is opened when the measurement image is detected. Further, the image forming apparatus comprises a controller which changes an image forming condition based on detection result of the density detection sensor.

An image forming apparatus includes an image bearer to bear a black toner pattern formed with a black toner image under an increased exposure amount and an increased developing bias. A first optical sensor detects an amount of reflection light reflected by the black toner pattern on the image bearer. The first optical sensor includes a light-emitting element to emit light toward the black toner pattern on the image bearer and a light-receiving element to receive the reflection light reflected by the black toner pattern on the image bearer. A toner adhesion amount converter converts the amount of the reflection light detected by the first optical sensor into a toner adhesion amount of toner adhered to the image bearer and adjusts an image density according to the toner adhesion amount.

An image forming apparatus includes a detection unit configured to detect a linear velocity change of a photosensitive drum, which occurs when the photosensitive drum rotates, and an exposure controller configured to control an exposure timing of the exposure unit based on the linear velocity change of the photosensitive drum, which is detected by the detection unit.

An image forming apparatus includes a conversion unit, an image bearing member, an image forming unit that forms an image on the image bearing member based on image data converted by the conversion unit, a measuring unit that measures a measurement image on the image bearing member, and a controller that controls the image forming unit to form a first measurement image, controls the measuring unit to measure the first measurement image, and generates a conversion condition based on a result of measurement of the first measurement image and a first feedback condition. In forming a chromatic color image after a predetermined number of monochrome images, the controller controls the image forming unit to form a second measurement image, controls the measuring unit to measure the second measurement image, and generates the conversion condition based on a result of measurement of the second measurement image and a second feedback condition.