An image forming apparatus comprises: an image processor to convert image data based on a conversion condition; an image forming unit to form an image based on the converted image data using a replaceable member; a memory to store the image data and the converted image data; a sensor to perform measurement on a test image; and a controller. If the replacement of the replaceable member is detected while forming images, the controller controls the image forming unit to form the test image and generates the conversion condition based on a result of the measurement on the test image. If the replacement of the replaceable member is detected while forming the images, the controller further controls the image processor to convert the image data stored in the memory based on the generated conversion condition.

A housing includes a first opening and a second opening, and encloses a light-emitting element, a first light receiving unit, and a second light receiving unit. The first opening is provided in a first light guide path arranged between the light-emitting element and a first irradiated region of the target surface, and is arranged so that light output from the light-emitting element travels toward the first irradiated region. The second opening is provided in a second light guide path arranged between the first irradiated region and the first light receiving unit, and is arranged so that diffused reflection light from the toner image passes through when the toner image passes the first irradiated region.

Provided is an image calibration method, an image formation device and a storage medium. The image calibration method includes: acquiring at least one of a first end color density value or a second end color density value of a calibration reference image along a direction to be calibrated; calculating a difference between the at least one of the first end color density value or the second end color density value and a target color density value, to obtain at least one of a first end color density difference value or a second end color density difference value; and performing uniformity calibration on an image to be calibrated if the at least one of the first end color density difference value or the second end color density difference value is greater than or equal to a preset difference threshold.

An apparatus comprising a first control unit that executes density correction processing on image data and generates an image signal, an image forming unit that forms an image on a recording medium on the basis of the image signal, and a second control unit that controls the image forming unit. The first control unit includes a specifying unit that transmits specifying information relating to the density correction processing to the second control unit. The second control unit includes an acquisition unit that acquires a parameter relating to the image forming apparatus, and an estimation unit that estimates a plurality of image densities corresponding to tone levels identified by the specifying information transmitted from the first control unit on the basis of the parameter acquired by the acquisition unit and transmits the plurality of image densities to the first control unit.

Provided is an image formation device including a photoreceptor configured to carry a toner image and a developer configured to form the toner image on a surface of the photoreceptor and configured such that the developer is a replaceable development unit, the image formation device including: a development bias application section configured to apply a development bias to between the photoreceptor and the developer; a stabilization control section configured to perform image stabilization control of determining a development bias value to be used in future by changing the development bias while measuring a density of the toner image formed by the developer, thereby obtaining the toner image with a target density; and a life determination section configured to determine expiration of use of the development unit when the development bias value determined by the stabilization control falls outside a preset acceptable range.

An image forming apparatus includes a photoreceptor, an exposure unit, a developing unit, and a control unit. The control unit sets the toner-layer-forming electric potential difference lower than an electric potential when forming the image on the print medium, forms a combined patch for calibration by the set toner-layer-forming electric potential difference for calibration, so as to adjust the developing-bias potential by measuring a print density of the formed combined patch. The combined patch includes a first patch and a plurality of second patches. The plurality of second patches have a width within a range of 0.2 mm to the predetermined value in the peripheral-velocity direction of the photoreceptor, extend with a length equal to or more than the predetermined value in the rotation-shaft direction of the photoreceptor, and are arranged at a predetermined interval in the peripheral-velocity direction of the photoreceptor.

An image forming apparatus includes a detection unit to detect a toner attached to an image carrying surface at a detection position. The first control unit controls the image forming unit such that a first check image including a patch pattern and a line pattern is formed. The relationship determination unit determines a correlation between a width of the line pattern and a density of an image to be formed based on a density of the patch pattern and a width of the line pattern. The determination unit determines an allowable range based on the determined correlation. The second control unit controls the image forming unit such that a second check image including the line pattern is formed. The line width determination unit determines a width of the line pattern based on a detection status relating to the line pattern. The monitoring unit monitors a formation status of the image by comparing the determined width and the determined allowable range.

An image forming apparatus includes an exposure unit provided with a rotatable polygon mirror including a plurality of reflecting surfaces for scanning a light beam emitted from a light source to expose a photosensitive member with the light beam according to image information. A determining unit determines an end of lifetime of the exposure unit based on a detecting result of density of a toner image detected by two detecting units at a first timing and a detecting result of density of the toner image detected by the two detecting units at a second timing after the first timing.

An image forming apparatus is provided. The apparatus comprises an image forming unit to form an image based on an image forming condition; a sensor to measure a measurement image formed by the image forming unit; and a controller to obtain information correlated with a change in density of an image to be formed by the image forming unit, control the sensor to measure the measurement image, determine first data related to density of the image to be formed by the image forming unit, determine, based on a result of measuring the measurement image, second data related to density of the image to be formed by the image forming unit, and generate the image forming condition based on a weighted average of the first data and the second data.

A processor causes a printing portion to execute test image transfer processing for transferring a plurality of test toner images onto an area outside a secondary transfer area on a surface of an intermediate transfer member, and secondary voltage stop processing for stopping a supply of a secondary transfer voltage. The processor acquires a plurality of first sensing densities. The processor causes the printing portion to execute the test image transfer processing and secondary voltage supply processing for supplying the secondary transfer voltage. The processor acquires a plurality of second sensing densities. The processor compares the plurality of first sensing densities and the plurality of second sensing densities to determine a state of a toner charging amount in each of the plurality of test toner images.