In an image forming apparatus (10), a seal member (436) is a non-conductive, flexible member supported by a developing device (43). The seal member (436) is formed to project from an edge part (43b) of the developing device (43) that faces an image carrying member (41), along a longitudinal direction (D1) of the image carrying member (41). The seal member (436) fills a part of a gap between the developing device (43) and an outer circumferential surface of the image carrying member (41). An electrode film (437) is adhered to a surface of the seal member (436). The electrode film (437) is a conductive film. A potential detecting device (642) detects a potential of the electrode film (437). A charging controller (8b) controls a charging voltage based on a result of comparison between a predetermined reference potential and the potential detected by the potential detecting device (642).

An image forming apparatus, to which an external measurement device is connectable, including an image processor, a printer, a sensor arranged on a conveyance path, a controller that performs first processing for generating color processing condition based on a measurement result of measurement images of the sensor, the measurement images including a first measurement image and a second measurement image, wherein a length of the second measurement image in a conveyance direction is longer than a length of the first measurement image in the conveyance direction, and performs second processing for generating conversion condition, based on a measurement result of predetermined measurement images by the sensor and measurement data output from an external measurement device, wherein a length of a predetermined measurement image included in the predetermined measurement images in the conveyance direction is longer than the length of the first measurement image in the conveyance direction.

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.

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.

Provided is an image forming apparatus, including a photosensitive member, a latent image forming unit configured to form an electrostatic latent image on the photosensitive member, a developing unit configured to store developer containing toner and to develop the electrostatic latent image on the photosensitive member using the developer, a detector configured to detect an amount of the toner stored in the developing unit, and a supplying unit configured to supply toner to the developing unit.

An image forming apparatus according to an embodiment includes an image forming unit, and a processor. The image forming unit forms an image on a printing medium. The processor performs user authentication and, upon performing the user authentication, determines whether or not an image stabilization process should be performed in the image forming unit. The processor then instructs the image forming unit to perform the image stabilization process according to a result of the user authentication.

A image forming system of the present inventation includes a control section that causes a pattern image for image density control to be formed on an image carrier, and performs density correction control for correcting a density of a formed image on the basis of density information on the formed pattern image for image density control, wherein the control section determines a timing for performing the density correction control, on the basis of information corresponding to a density difference generated between images formed by the plurality of image forming apparatuses.

An image forming apparatus includes a control unit configured to be able to perform density adjustment control of forming a reference toner image for image density control on an image bearing member and changing a target value of a toner density based on an image density of the reference toner image detected by an image density detection unit. The control unit limits the target value of the toner density within a predetermined range, and changes frequency of execution of the density adjustment control based on the fact that the target value of the toner density is placed at a boundary value.

An image forming apparatus includes a converting unit, a plurality of image forming units, a scanning unit, a first generating unit, a second generating unit, an intermediate transfer member, a measuring unit, and a controller configured to, after the first generating unit generates an image forming condition, control the plurality of image forming units to form a measurement image, control the measuring unit to measure the measurement image, and control whether to control the second generating unit to generate a conversion condition or not on the basis of a result of the measurement performed on a previous measurement image and a result of the measurement performed on a current measurement image.

In an image forming apparatus, a storage portion stores a target adhesion amount of toner to adhere to an image bearing member at each of gradation levels as a target gradation level and a setting value of a control parameter used for control on the image forming portion at the target gradation level. A first control processor makes an adhesion amount sensor measure an actual adhesion amount corresponding to the setting value and thereafter compares a resultant measured value and the target adhesion amount and corrects the setting value if needed in association with at least one of the target gradation levels as a subject. A second control processor makes the image forming portion output a calibration image used for correcting the target adhesion amount using a period when the first control processor performs processing if there arises a need to correct the target adhesion amount associated with the subject.