Abstract: An image forming apparatus includes an image bearer, a charger, an exposure device, a developing device, an image density sensor, and a controller. The controller is configured to charge the image bearer, expose the image bearer with a first exposure that saturates potential of the image bearer after exposure to form a latent image pattern on the image bearer, develop the latent image pattern into a toner pattern while changing a developing electrical field, detect a first image density of the toner pattern, determine developing bias and charging bias, form patterns with the first exposure and a second exposure smaller than the first exposure, detect a second image density of the patterns, and determine an exposure to output an image based on the second image density, the first exposure, and the second exposure.

Abstract: A toner supplying device including a secondary toner container, a first feeding member performing a first feeding operation of feeding toner from a toner container to the secondary container on demand, a second feeding member performing a second feeding operation of feeding the toner from the secondary container to a developing device on demand, and a toner supply controller controlling the amount of the toner in the secondary container to be greater than a predetermined amount. The controller performs first control in which when the first feeding operation is performed, the amount of the toner fed in the second feeding operation per unit of time is decreased, or second control in which when the amount of the toner fed in the second feeding operation is greater than a predetermined amount, the amount of the toner fed in the first feeding operation per unit of time is decreased.

Abstract: In an embodiment, a diffuse reflection output conversion method is executed in an apparatus detecting a plurality of gradation patterns. The apparatus includes a light emitter and light receiver, and detects specular reflection and diffuse reflection simultaneously. A region before specular reflection saturation is a region where the specular reflection component decreases and saturates at minimum level. A diffuse reflection detector is calibrated by: obtaining a diffuse reflection output resulting from an amount of attached powder at a border between the region before specular reflection saturation and the region after specular reflection saturation; calculating a ratio between the diffuse reflection output and a reference diffuse reflection output calculated in advance as a calibration coefficient; and multiplying a diffuse reflection output obtained from the gradation patterns by the calibration coefficient calculated at the calculating.

Abstract: A developing device for developing an electrostatic latent image on an image bearing member including a developer bearing member opposed to the image bearing member to bear thereon a developer including a toner and a magnetic carrier; a developer containing part to contain the developer to supply the developer to the developer bearing member; an agitating or feeding member to agitate or feed the developer in the developer containing part; a magnetic permeability sensor to measure magnetic permeability of the developer to determine toner concentration of the developer; a developer feeder; a feeding member to feed the developer to the developer containing part through the developer feeder; and a driver to drive the feeding member independently of the agitating or feeding member. The magnetic permeability sensor is arranged on the developer feeder.

Abstract: A developing device for developing an electrostatic latent image on an image bearing member including a developer bearing member opposed to the image bearing member to bear thereon a developer including a toner and a magnetic carrier; a developer containing part to contain the developer to supply the developer to the developer bearing member; an agitating or feeding member to agitate or feed the developer in the developer containing part; a magnetic permeability sensor to measure magnetic permeability of the developer to determine toner concentration of the developer; a developer feeder; a feeding member to feed the developer to the developer containing part through the developer feeder; and a driver to drive the feeding member independently of the agitating or feeding member. The magnetic permeability sensor is arranged on the developer feeder.

Abstract: In an embodiment, a diffuse reflection output conversion method is executed in an apparatus detecting a plurality of gradation patterns. The apparatus includes a light emitter and light receiver, and detects specular reflection and diffuse reflection simultaneously. A region before specular reflection saturation is a region where the specular reflection component decreases and saturates at minimum level. A diffuse reflection detector is calibrated by: obtaining a diffuse reflection output resulting from an amount of attached powder at a border between the region before specular reflection saturation and the region after specular reflection saturation; calculating a ratio between the diffuse reflection output and a reference diffuse reflection output calculated in advance as a calibration coefficient; and multiplying a diffuse reflection output obtained from the gradation patterns by the calibration coefficient calculated at the calculating.

Abstract: An image forming apparatus includes a problem-occurrence determining unit, a problem-occurrence area determining unit, and a notifying unit. If the problem-occurrence determining unit determines that a problem has occurred in an image forming process, the problem-occurrence area determining unit determines whether the problem is caused by a toner filling process on the basis of toner-filling control data and toner-supply control data. The notifying unit then notifies the determination as to whether the problem is caused by the toner filling process.

Abstract: An image forming apparatus forms a plurality of tone patterns of different colors, each of which containing a plurality of toner patches having different toner densities. Some of the toner patches in each of the tone patterns are formed with a predetermined fixed developing bias and the rest of the toner patches in each of the tone patterns are formed with developing biases set based on previous developing biases that have been obtained through a previous control process. The largest toner density of the toner patches in each of the tone patterns is determined based on a magnitude relation of previous index values obtained through the previous control process.

Abstract: An image forming apparatus is disclosed that includes an image density control unit that performs control operations based on an image density control condition that is adjustably set to control an output image to have a predetermined image density, an image density control condition modifying unit that calculates a modified image density control condition based on information on an amount of toner exchanged at a developing apparatus within a predetermined period and a parameter for image density control condition calculation and sets the modified image density control condition as the image density control condition to be used by the image density control unit, and a parameter modifying unit that modifies the parameter for image density control condition calculation used by the image density control condition modifying unit based on a toner pattern detection result obtained by detecting a toner pattern formed on a belt member.

Abstract: A process cartridge for use in an image forming apparatus includes an image bearing member and a developing unit. The developing unit includes a developer bearing member to bear developer including toner and carrier, a casing forming a developer container containing the developer, a screw having a shaft with a spiral screw blade, a toner density sensor to detect a density of the toner on a detection surface, and a detection surface agitating member fixedly mounted on the shaft of the screw at a position facing a detection surface to scrape away the developer accumulated on the detection surface as the screw rotates. The detection surface agitating member includes an elastic sheet elastically deformable to scrape away the developer accumulated on the detection surface and disposed at a substantially same angle to an axial direction of the shaft of the screw as the spiral screw blade.

Abstract: An image forming apparatus includes an image carrier configured to carry an image and a charger to which a direct current voltage overlapped with an AC voltage is applied as a charging bias to charge the image carrier. The charger is positioned in contact or contactlessly with the image carrier. The AC voltage applied to the charger in an adjustment of the AC voltage is not less than twice a charging start voltage Vth at which the image carrier starts to be charged.

Abstract: An image forming apparatus includes multiple image forming units to form different single-color images with respective different color developers and a control system to selectively perform a multicolor image forming operation, a specific-color image forming operation, a multicolor image quality correction operation, and a specific-color image quality correction operation.

Abstract: An image forming apparatus includes an image forming unit configured to form a plurality of toner images on an image carrier, an optical detector configured to detect reflection light from the toner image, and dedicated to detect infrared rays and near-infrared rays, and a controller configured to perform a predetermined control using a detection results of the optical detector. Gradation pattern that is comprised of a plurality of toner patches formed in the image forming unit with an image forming condition to have different adhesive amounts, and is formed of at least two colors, and detection values detected by the optical detector are used for the predetermined control.

Abstract: An image forming apparatus includes a control device that calculates a developing ability of the developing device based on a detection value detected by an optical detection device from the plural toner patches. The control device adjusts an image formation condition based on the calculated developing ability. A factor detection device is provided to detect a contributing factor that causes the developing ability to largely change after the last adjustment of the image formation condition. The control device controls image formation such that when the factor detection device does not detect the contribution factor and a developing ability calculated this time is different from that calculated last time (as to a part of the plural toner patches), the plural toner patches are formed based on a prescribed fixed image formation condition so that an attraction amount of toner attracting to the plural toner patches enter a prescribed range detectable for the optical detection device.

Abstract: An image forming apparatus and an image density control method for controlling image density in the image forming apparatus, involving adjusting a toner concentration control reference value in accordance with an amount of the toner replaced in a developing device so as to adjust the image density to maintain a consistent developability and changing image forming intervals in accordance with an amount of the toner replaced in the developing device during continuous printing operation.

Abstract: An image forming apparatus, which comprises a toner density detection device for detecting the density of a toner inside a developing device, acquires the number of pixels from inputted image information, calculates the toner replenishment amount from the toner density detection value and the information on the pixels, and thereby performs replenishment control so that excessive replenishment or insufficient replenishment of the toner is not caused. The upper limit value of the amount of toner to be replenished at once to the developing device is changed in accordance with the amount of information on an input image such as the image area, pixels of the input image.

Abstract: A toner supplying device including a secondary toner container, a first feeding member performing a first feeding operation of feeding toner from a toner container to the secondary container on demand, a second feeding member performing a second feeding operation of feeding the toner from the secondary container to a developing device on demand, and a toner supply controller controlling the amount of the toner in the secondary container to be greater than a predetermined amount. The controller performs first control in which when the first feeding operation is performed, the amount of the toner fed in the second feeding operation per unit of time is decreased, or second control in which when the amount of the toner fed in the second feeding operation is greater than a predetermined amount, the amount of the toner fed in the first feeding operation per unit of time is decreased.

Abstract: An image forming apparatus includes an image carrier configured to carry an electrostatic latent image, a developing device configured to develop the electrostatic latent image with a two-component developer including toner and magnetic carrier, a toner supplier configured to supply the toner to the developing device, a toner concentration detector configured to detect toner concentration in the two-component developer inside the developing device, and a controller. The controller is configured to detect first information to determine toner replacement amount in the developing device during a predetermined time period and second information to determine a charge characteristic of the toner in the developing device, change a toner concentration control reference value based on the first information and the second information, and control the toner concentration based on an output from the toner concentration detector and the toner concentration control reference value.

Abstract: In a reuse method for reusing a reusable device and a sensor of a first image forming apparatus having a first process linear velocity in a second image forming apparatus having at least one second process linear velocity different from the first process linear velocity, the reusable device and the sensor are installed in the first image forming apparatus, and when the first image forming apparatus switches from the first process linear velocity to the second process linear velocity at an initial state before the reusable device is used, output of the sensor at the second process linear velocity is measured. When information on the output of the sensor at the second process linear velocity is stored, the reusable device and the sensor are removed from the first image forming apparatus and installed in the second image forming apparatus.

Abstract: In an image forming apparatus a developing device develops an electrostatic latent image on an image carrier with a developer that contains toner to obtain a toner image, a toner-amount detecting unit detects amount of toner attached to the toner image, and a toner-density detecting unit detects a density of toner in the developer. Moreover, a process control unit corrects a toner-density target value indicative of a target value of density of toner in the developer based on the amount of toner detected by the toner-amount detecting unit and the density of toner detected by the toner-density detecting unit, and a determines execution timing of next process based on corrected toner-density target value.