Provided is an image forming apparatus having a simple configuration capable of measuring a toner current included in a developing current and accurately calculating a toner charge amount based on the measurement result. The developing device has a developer carrier that carries a two-component developer including a magnetic carrier and toner. The density detecting device detects the density of the toner image. The current detecting unit detects a DC component of a developing current that flows when a developing voltage is applied to the developer carrier. The control unit, in a state in which the image carrier is rotated at two or more different linear speeds during non-image formation, forms the same reference image on the image carrier by the developing device, and estimates the toner charge amount based on the developing current when the reference image is formed and the density of the reference image.

An image forming apparatus includes an image carrier, a charging unit, an exposure unit, a developing unit, a transfer device, a sensor, and a processor. The processor compares a surface potential difference between a first surface potential and a second surface potential of the image carrier to a threshold to detect that a surface potential difference exceeding the threshold is generated in the image carrier in a state where the supply of the developer from the developing unit to the image carrier is inhibited, the first surface potential being a surface potential of the image carrier to which the transfer bias measured by the sensor is not applied, and the second surface potential being a surface potential of the image carrier to which the transfer bias is applied.

An image forming apparatus includes: a developer carrier; a screw-shaped developer feeder that feeds developer to the developer carrier; an image carrier on which an image is imaged with toner of the developer; a developing current detector that detects developing current between the image carrier and the developer carrier during imaging; and a controller that detects image density failure that is periodic and oblique to a rotation direction of the image carrier. The controller causes a stripe image to be imaged on the image carrier and analyzes change of the developing current with time during imaging of the stripe image, thereby detecting the image density failure. The stripe image has a width in a length direction of the image carrier narrower than a period of a blade of the developer feeder and has a length in the rotation direction longer than a period of the image density failure.

An example image forming apparatus includes a charger, a developing device, a sensor, and a controller. The charger may apply a plurality of charging voltages to a photoconductor, the plurality of charging voltages having different magnitudes and respectively corresponding to a plurality of area sections constituting a test pattern and the developing device may supply a developer to the photoconductor. The sensor may sense an image formed by the supplied developer and corresponding to the test pattern. The controller may determine a remaining lifetime of the photoconductor based on the image corresponding to the test pattern.

An image forming apparatus that forms images on sheets, includes: a collection unit configured to collect history information relating to operation of the image forming apparatus; a selection unit configured to select, from among a plurality of accomplishment items, an accomplishment item relating to the operation of the image forming apparatus based on the history information; an acquisition unit configured to notify a user of one or more operation options related to the operation of the image forming apparatus that are for accomplishing the accomplishment item selected by the selection unit, and to acquire a selection result of whether or not the one or more operation options are to be used; and an operation control unit configured to control the operation of the image forming apparatus in accordance with the selection result.

According to one embodiment, an image forming apparatus includes a photoreceptor, a charging member, an application unit, and a control unit. An image is formed on the photoreceptor. The charging member is in contact with or close to a surface of the photoreceptor. The application unit applies a voltage to the charging member. The control unit performs control so that a current flowing through the charging member and the photoreceptor becomes a constant current when the photoreceptor is in an unused state, measures a voltage when the constant current flows and stores the measured voltage as a reference voltage, and controls the application unit to apply a voltage obtained by adding correction according to a value indicating a usage amount of the photoreceptor to the reference voltage.

An image forming apparatus includes a developing roller, a photoconductor drum, a density detector, a current detector, and a controller. The developing roller carries a toner. The photoconductor drum carries a toner patch. The density detector detects toner density of the toner patch. The current detector detects developing current flowing to the toner patch. The controller calculates an inclination of an approximate straight line approximating a relation between the toner density and the developing current. The developing roller develops three or more toner patches, different in toner density and different in developing current from one another, on the photoconductor drum. The controller calculates the inclination, using different mathematical expressions depending on whether three toner patches or four toner patches are provided.

An image forming apparatus includes a rotatable photosensitive member, a charging unit, a developing unit, a support frame, and a sensor unit. The sensor unit is detachably attached to the support frame in a direction that intersects a rotation-axis direction of the photosensitive member and includes a potential sensor, a support portion, a fixing portion, an electric board, and a linking portion. The support portion supports the potential sensor at an area from the charging unit to the developing unit in a rotational direction of the photosensitive member. The fixing portion is fixed to the support frame at a position that faces an area from the developing unit to the charging unit in the rotational direction of the photosensitive member. The support portion is positioned with respect to the support frame at a position downstream of the support portion in an attachment direction of the sensor unit.

A binary ink developer (BID) may include a power supply electrically coupled to an electrode, a developer roller, and a cleaner roller. The BID may also include a controller to determine a level of image ghosting based on a sum of currents at the electrode, the developer roller and the cleaner roller, and instruct the power supply to provide an adjusted voltage to the cleaner roller in response to a determination of the level of image ghosting.

An image forming apparatus includes an image forming portion, an image bearing member, a transfer member, a voltage source, a density detecting portion, a display portion, a controller, and an operating portion. The controller is capable of executing an operation in a mode in which a test chart for adjusting a transfer voltage is outputted, and setting information on the transfer voltage set for during transfer on the basis of a detection result when the test chart is detected by the detecting portion is displayed at the display portion and is checked by user. The controller causes the display portion to display setting information on the basis of a correcting value and causes the user to check the setting information in the operation in the mode executed after the correcting value is inputted from the operating portion.