An image forming apparatus includes optical sensor units provided opposed to an image bearing member; light blockers provided between the image bearing member and the optical sensor units, respectively, the blockers being movable between locking and exposing positions, respectively; calibration members provided where the light is incident when the blockers are in the blocking positions, respectively, the calibration members calibrating data acquired by the optical sensor units; a movable link connected with the blockers; a switching portion for switching the blockers between the exposing and blocking positions; and a positioning portion for determining the blocking position, the positioning portion being disposed at a position where at least one of the blockers is contacted to the positioning portion when the blockers are switched from the exposing positions to the blocking positions.

An image forming apparatus includes an image forming device, an image density detector, and a processor. The processor controls the image forming device to form a first test toner image, and controls the image density detector to detect an image density at the plurality of positions of the first test toner image. The processor adjusts an image forming condition so that the image density detected at each of the plurality of positions becomes a target image density, controls the image forming device to form a second test toner image based on the adjusted image forming condition, controls the image density detector to detect an image density at the plurality of positions of the second test toner image, determines whether a streak exists in the second test toner image based on the detected image densities, and executes a countermeasure to prevent an occurrence of the streak.

An image forming apparatus includes an image forming unit and a controller. The image forming unit includes a latent image bearer, a charger to charge the latent image bearer, an exposure device to expose a latent image on the surface of the latent image bearer, and a developing device to develop the latent image with a developer. The controller executes an image forming process, a first fluctuation control that cyclically changes a developing bias supplied to the developing device based on predetermined first pattern data, and a second fluctuation control that cyclically changes a charging bias supplied to the charger based on predetermined second pattern data, in parallel. The controller executes a determination process to determine whether the controller executes the first fluctuation control. When the controller determines not to execute the first fluctuation control, the controller determines not to execute the second fluctuation control, too.

Provided is an image forming apparatus that reduces replacement frequency for waste toner container, and efficiently performs waste toner accommodation with a waste toner container. The image forming apparatus includes a toner detection sensor detecting a quantity of a toner in a toner container; a waste toner detection sensor detecting an accommodation quantity of a waste toner removed from a photosensitive medium and accommodated in a waste toner container; a waste toner container full-state forecasting part that, upon toner detection sensor detecting empty state of toner container, forecasts whether waste toner container is filled up with waste toner before toner container newly loaded is emptied, on detection result by waste toner detection sensor; and a system control part that, upon waste toner container full-state forecasting part forecasting waste toner container being filled up, notifies a replacement message urging replacement of waste toner container to a panel part.

An image forming apparatus includes a plurality of image formers each capable of forming, on a sheet, an overlap image and a non-overlap image, a fixer that fixes, on the sheet, a whole image composed of the overlap images and the non-overlap images, and a hardware processor that controls each of the plurality of image formers such that a difference in image at a boundary between the overlap image and the non-overlap image is reduced in the whole image.

A density correction unit (a1) obtains density measurement values of a surface in a measurement section of an image carrier at a first round, (a2) calculates as section background data at the first round respective differences between the density measurement values at the first round and an average value thereof, (a3) obtains density measurement values of a surface at least in the measurement section at a second round, (a4) calculates as section background data at the second round respective differences between the density measurement values at the second round and an average value thereof in a specific section with the same length as the measurement section, and (a5) determines the rotation period on the basis of a correlation between the section background data at the first round and at the second round. Here the measurement section is a part in a circulating direction of the image carrier.

To provide an image forming device that can be efficiently maintained. According to one embodiment, the image forming device includes a plurality of photoconductors, an exposure device, a developer, and a processor. The exposure device irradiates a corresponding surface of the plurality of photoconductors with light corresponding to an image formed on a corresponding photoconductor of the plurality of photoconductors. The developer supplies a toner to the corresponding surface of the plurality of photoconductors on which an electrostatic latent image is formed by the light emitted by the exposure device. The processor adjusts, for every photoconductor, a contrast potential for supplying the toner from the developer to the electrostatic latent image formed on the corresponding surface of the plurality of photoconductors, and notifies a warning when there is a contrast potential whose difference from another contrast potential exceeds a reference value.

An image forming apparatus includes a processing unit, a sensor, and a processor. The processing unit has a developing device using a developer containing two components of a toner and a carrier. The sensor outputs a detection value corresponding to a toner concentration of the developer during operation of the processing unit. The processor performs a process of determining whether a service call to a service person is necessary based on the detection value of the sensor. The processor operates the processing unit at either a high process speed or a low process speed to acquire the detection value of the sensor, before determining whether the service call is necessary. The processor determines the process speed at which the processing unit is to be operated based on the detection value. The processor operates the processing unit at the determined process speed to determine whether the service call is necessary.

An image forming apparatus includes an image bearing member, a transfer device, an applying portion; a detecting portion, a controller, and a receiving portion. The controller executes an operation in a setting mode in which during non-image formation, test images are transferred onto the recording material at different test voltages to the transfer device and then a transfer voltage applied to the transfer device during image formation is set on the basis of a detection result of the detecting portion. In a case that the operation in the setting mode is executed to set the transfer voltage for one-side mode, the receiving portion is capable of receiving instruction information selectively instructing a setting condition of the transfer voltage set by the operation in the setting mode from setting conditions including a first setting condition and a second setting condition.

An image forming apparatus includes a platen on which an original is to be placed, a feeder configured to feed an original placed on a tray, a sensor configured to detect a sheet on the tray, a lamp provided to the feeder, a reader configured to read the original placed on the platen and to read the original conveyed by the feeder, an image forming unit configured to form an image on a sheet, and a controller. The controller is configured to control the image forming unit to form a test image on a sheet, control the reader to read the test image formed on the sheet placed on the platen, control a density of the image to be formed by the image forming unit based on a reading result of the test image.