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 a photoconductor, a light source, an optical scanning device, an image bearer, an image density sensor, an image processing circuit, and a light source driver. The plurality of images are formed with a plurality of light intensities and a plurality of image area rates on the image bearer. The image density sensor detects a plurality of image densities of the plurality of images at a plurality of positions in a main scanning direction. The image processing circuit determines a light intensity correction value to correct an image density of a target image in the main scanning direction based on the plurality of light intensities, image area rates, image densities, and positions, and the image area rate of the target image, and outputs a control signal to adjust a light intensity. The light source driver adjusts the light intensity based on the control signal.

A video count value is acquired per unit area predetermined in a direction in which a recording medium is conveyed, based on recording target image data. When an image has been formed on an area of the recording medium from which the video count value has been acquired, control is performed by using the acquired video count value so that a developing unit is replenished with an amount of toner corresponding to the video count value acquired from the area.

An image forming apparatus includes an intermediary transfer member; a first image forming portion including a first developing device and a detecting portion; a second image forming portion including a second developing device; a contact-and-separation mechanism capable of setting a first state and a second state; and an executing portion capable of executing an operation in a first monochromatic mode in the first state and capable of executing an operation in a second monochromatic mode in the second state. When a toner amount in the first developing device is below a predetermined amount on the basis of the detecting portion during an image forming operation for continuously forming the black image in the operation in the first monochromatic mode, the executing portion continuously executes the image forming operation in the second state.

A moving member is disposed between an upper guide, which guides a conveyed transfer material and to which a voltage is applied from a power source, and a lower guide, which guides the conveyed transfer material, the upper guide being disposed on an upstream side with respect to a photosensitive drum in a conveyance direction of the transfer material. The moving member is supported by the upper guide, and is capable of abutting against and separating from the lower guide. By being pushed by the transfer material, the moving member transitions from a first state in which the moving member is abutted against the lower guide to a second state in which the moving member is separated from the lower guide.

An image forming apparatus includes a developing device that performs a developing process by using two-component developer; an image carrier that carries a toner image including a toner band developed by the developing device; a density detection unit that detects a density of the toner band; and a determining unit that determines whether or not to perform a density adjustment on the basis of the density of the toner band detected by the density detection unit.

An image forming apparatus includes a voltage applying unit that applies a bias voltage for enabling a transfer unit to transfer a developer layer to a transfer medium, the developer layer being retained by an image carrier in accordance with image information; a measuring unit that measures a surface potential of the developer layer; and a setting unit that sets a value of the bias voltage to be applied by the voltage applying unit in accordance with the surface potential measured by the measuring unit, a combined electrostatic capacitance of a surface layer of the image carrier and the developer layer, and an electrostatic capacitance specific to the transfer medium.

An image forming apparatus includes an image forming unit configured to form an image by using a developer, and a controller configured to control the image forming unit to form a test image on the sheet, acquire information related to the test image, and correct, based on the information, a position on the sheet, wherein the test image is used to detect positional deviation, wherein the controller performs first processing in which the image forming unit forms the test image and a first pattern image, and second processing in which the image forming unit forms the test image and a second pattern image, wherein the image forming unit forms the first pattern image so that an adhesion amount of the developer becomes a first amount, and the second pattern image so that an adhesion amount of the developer becomes a second amount that is larger than the first amount.

An image forming apparatus that forms an image on a transfer material in an image forming mode, includes: a photoreceptor rotatable in a predetermined rotation direction; a developer that forms a toner image on the photoreceptor using a two-component developing agent including toner and a carrier; a transferor that transfers the toner image on the photoreceptor onto the transfer material; a carrier collector that applies an electric field corresponding to a collecting bias to a carrier adhering to the photoreceptor to collect the carrier; a carrier detector that detects a carrier remaining on the photoreceptor after collecting the carrier by the carrier collector; and a hardware processor that sets the collecting bias in the image forming mode on the basis of the amount of carriers detected by the carrier detector when a carrier adhesion detecting mode for forcibly causing a carrier to adhere to the photoreceptor is executed.

An integrated sensor has a density detection sensor, a sensor board, and a potential sensor pattern. The density detection sensor detects the density of a toner image formed on a toner image carrying member. On the sensor board, the density detection sensor is mounted. The potential sensor pattern is provided on the sensor board, and detects the potential of the toner image.