An image forming apparatus includes a plural image forming units each having a plural image forming sections, and an intermediate transfer body on which toner images formed by the plural image forming sections are primarily transferred, a plural secondary transfer units that are provided corresponding to the plural image forming units, and secondarily transfer the toner images of the intermediate transfer body to a recording medium, and a processor, in which each image forming unit has the image forming section of the same color, and the processor is configured to: in response to an instruction to output a color chart of the same color, execute a mode in which the color chart of the toner image having a density of intermediate gradation, formed by the image forming section of the same color for each image forming unit, is secondarily transferred to the recording medium and output.

An image-forming apparatus includes a generating unit that generates correction data for correcting an unevenness in light amount of an exposure head using a read image of a correction chart, and a correction unit that corrects image data for image formation based on the correction data. The exposure head includes light-emitting chips each of which includes light-emitting elements. The correction chart includes a plurality of regions arranged in a direction, a first reference mark located on one side of the regions, and a second reference mark located on the other side of the regions. The generating unit determines partial regions respectively formed by the light-emitting chips within the regions based on positions of the first and second reference marks in the read image of the correction chart, and generate the correction data based on a result of measurement on the partial regions.

An image forming apparatus includes an image bearing member, a rotatable endless intermediary transfer belt, an inner roller, an outer roller, a power source, a detecting portion, and a controller. On the basis of a result of detection by the detecting portion when a voltage is applied to the inner roller so as to form a chart on a recording material of a predetermined kind in an operation in an adjusting mode, the controller determines whether a transfer voltage when a toner image is transferred onto the recording material of the predetermined kind is subjected to constant-voltage control so that the voltage applied to the inner roller by the power source becomes a target value or is subjected to constant-current control so that a current supplied to the inner roller becomes a target value.

An image forming apparatus includes an image former; a detector; and a hardware processor that: calculates a minimum area for each of the plurality of tones based on image data of the image, calculates a density ratio between the densities before and after the transferring is made for each of the plurality of tones from the densities detected by the detector, extracts as a first area a minimum area of a tone corresponding to a density ratio which switches from less than a predetermined threshold to equal to or more than the threshold, and extracts as a second area a minimum area of a tone the density ratio of which is a maximum, and changes a setting of a dot size of the image so that a size of the second area becomes the same as a size of the first area until the next setting change is performed.

According to one embodiment, there is provided a toner cartridge used in an image forming apparatus including a processor which forms a toner pattern image on a photoconductive member, transfers the toner pattern image on a medium, and changes an image forming condition based on a detection result obtained by optically detecting the toner pattern image transferred onto the medium, the toner cartridge including: a toner accommodating container accommodating a toner, and a memory. The memory stores reference data which is determined according to toner characteristics in the toner accommodating container, and is used for applying a reference value for an optical detection result of a toner pattern formed by the toner on the medium.

A toner detection unit (optical sensor) includes a first light receiving element configured to receive specular reflection light of first irradiating light, and a second light receiving element configured to receive diffused reflection light of second irradiating light, and a separation component configured to separate irradiating light emitted from an LED into the first and second irradiating light. A housing forms a first opening through which the first irradiating light and the second irradiating light pass and the diffused reflection light to be received by the second light receiving element passes, and a second opening through which the specular reflection light to be received by the first light receiving element passes.

An image forming apparatus includes a latent image bearer configured to bear a latent image and a developing device configured to develop the latent image on the latent image bearer with developer. The developing device includes a plurality of developer bearers configured to bear the developer. The image forming apparatus further includes a rotation position detector configured to detect a rotation position of at least one of the plurality of developer bearers, a common power source configured to apply a developing bias to each of the plurality of developer bearers, and circuitry configured to cause the common power source to periodically vary the developing bias. The circuitry is configured to cause the plurality of developer bearers to rotate in a same rotation period; and vary an output value of the developing bias in a same period as the rotation period based on a detection result by the rotation position detector.

An image forming apparatus capable of detecting a development nip disengaging error and a method of detecting a development nip disengaging error are provided. According to an example method, a test pattern is formed on a photoconductor of an image forming apparatus, the test pattern transferred to an intermediate transfer belt is detected through a sensor from a time when an operation of an adjusting member moving a developing roller is controlled such that the developing roller moves from a disengaging position where the developing roller is spaced from the photoconductor to disengage a development nip from the photoconductor to a developing position where the developing roller is in contact with the photoconductor to form the development nip, and whether the development nip disengaging error occurred is determined based on the detected test pattern.

An image forming apparatus includes an image bearer, a driver, an image forming device, a sensor, and circuitry. The driver drives and rotates the image bearer. The image forming device forms a toner image on the image bearer driven and rotated by the driver. The sensor emits light to the image bearer and receives reflected light. The circuitry controls the driver and the image forming device to form a first toner image with a first color and a second toner image with a second color different from the first color. The circuitry controls the sensor to detect specularly reflected light and diffusely reflected light from the first toner image and the second toner image. The circuitry calculates an amount of misalignment of the first toner image and the second toner image based on a value of the specularly reflected light and a value of the diffusely reflected light.

An image forming apparatus includes a storage unit and a charging amount acquisition unit. The charging amount acquisition unit forms a measurement toner image on the image carrier while changing the frequency of the alternating current voltage of the development bias with the potential difference in the direct current voltage between the developing roller and the image carrier being kept constant, acquires a tilt of a measurement straight line representing a relationship between the change amount of the frequency and the density change amount of the measurement toner image, based on the change amount of the frequency and a result of detecting density of the measurement toner image in the density detecting unit, and acquires a charging amount of the toner included in the measurement toner image formed on the image carrier based on the acquired tilt of the measurement straight line and the reference information in the storage unit according to the toner density detected by the toner density detecting unit.