Abstract: Presented is an image forming apparatus that includes a plurality of photoconductors, a sensor, a first memory, and a processor. The photoconductors include first and second photoconductors on which a toner image is formed in response to an image being formed. The sensor detects a physical amount that changes in response to a deterioration state of the first photoconductor. The first memory collects and stores a history of the physical amount and usage status information relating to a usage status of the first photoconductor. The processor performs a prediction of a lifespan of the second photoconductor and determination of a failure of the second photoconductor based on the history of the physical amount and the usage status information of the first photoconductor, and usage status information relating to a usage status of the second photoconductor.

Abstract: A print apparatus is disclosed. The print apparatus includes a photoconductive surface to receive a latent image representative of an image to be printed onto a printable substrate; a charging component to apply a voltage is to be applied to the photoconductive surface as the charging component moves relative to the photoconductive surface; and processing circuitry to receive data indicative of a measurement of a first current resulting from the voltage applied by the charging component; determine, responsive to detecting an increase in the measured first current relative to a reference current, the increase being greater than a first defined threshold current, that there exists a point defect under affecting the latent image; and generate instruction data responsive to determining that there exists a point defect under affecting the latent image. A method and a machine-readable medium are also disclosed.

Abstract: An image forming apparatus includes an image forming unit configured to form an image on a sheet based on image data, a control unit configured to control driving of the image forming unit, and a power supply unit configured to, if a factor for shifting from a power saving state to a standby state is detected, supply power to the image forming unit and the control unit. If a first type of factor is detected as the factor in the power saving state, the power supply unit supplies power to the control unit and the image forming unit, and the control unit restricts the driving of the image forming unit. If an instruction to perform a function of forming an image on a sheet is accepted, the control unit cancels restriction of the driving of the image forming unit.

Abstract: An image forming apparatus includes a photoconductor, a charger, a detection unit, and a determination unit. The charger charges the photoconductor. The detection unit detects an actual charging potential of the photoconductor after the photoconductor is charged by the charger. The determination unit determines one of a plurality of causes related to a charging abnormality of the photoconductor based on a relationship between a standard charging potential of the photoconductor to be obtained by charging by the charger and a charging potential detected by the detection unit.

Abstract: An image forming apparatus includes a developer bearing member, a supply member, first and second voltage application units, and a control unit. Assuming that a difference between a voltage to be applied to the developer bearing member by the first voltage application unit and a voltage to be applied to the supply member by the second voltage application unit in the image forming operation is defined as a first supply contrast, and a difference between the voltage to be applied to the developer bearing member by the first voltage application unit and the voltage to be applied to the supply member by the second voltage application unit in the preliminary rotation operation is defined as a second supply contrast, the control unit controls the second supply contrast to be less than the first supply contrast or to have polarity reversed from polarity of the first supply contrast.

Abstract: An image forming apparatus includes a print engine including a photosensitive drum forming an image on an image forming medium, a charging member charging the photosensitive drum, a power supply to provide a charging power supply having a reference charging voltage to the charging member, a sensor to detect an image density of an image formed on the image forming medium, and a processor to control the power supply to change a magnitude of voltage of the charging power supply within a predetermined voltage range at predetermined periods, and to identify an occurrence of a background with respect to the photosensitive drum based on an image density detected by the sensor while the charging power supply is changed.

Abstract: Apparatus and methods are disclosed for particle beam focusing, suitable for use in sample preparation or test environments, including SEM-based nanoprobing platforms. With a particle beam incident on a sample surface, stage current is used as an indicator of spot size. By scanning or searching settings of a working distance control, a control value having maximum (or minimum) stage current is used to set the beam waist at the sample surface. Alternatively, minima (or maxima) of reflected current can be used. Stigmator controls can be adjusted similarly to reduce astigmatism. The scan of control settings can be performed concurrently with sweeping the beam across a region of interest on the sample. Curved sweep patterns can be used. Energy measurements can be used as an alternative to current measurement. Applications to a nanoprobing workflow are disclosed.

Abstract: An image forming apparatus includes an image carrier, a toner supply unit, an application roller adjacent to the image carrier, a toner measuring unit, and a control unit. The toner supply unit supplies toner to the image carrier. The application roller applies a lubricant to the image carrier. The toner measuring unit measures an amount of toner transferred from the image carrier to the application roller. The control unit adjusts the supply of toner to be supplied to the image carrier in accordance with the amount of toner measured by the toner measuring unit.

Abstract: A method of encoding information on a material substrate and a device including the modified material substrate are provided. The method includes providing a material substrate having at least one exposed surface or interior (bulk) location with an initial material state, treating the exposed surface or interior location with an energy source, wherein the energy source encodes encryption information on the exposed surface or interior location to provide a modified material substrate having an exposed surface or interior location with an intermediate material state, and then treating the exposed surface or interior location with an intermediate material state with the energy source to encode decipher information on the exposed surface or interior location to provide a remodified material substrate having an exposed surface or interior location with a final material state.

Abstract: An image forming apparatus includes an image bearing member, a charging member, an exposure unit which performs first exposure to form a non-image portion potential on the electrically charged surface of the image bearing member, and second exposure to form an image portion potential thereon, a developing member, a charging voltage application unit, a current detection unit which detects a current flowing from the image bearing member to the charging member, and a control unit which controls the exposure unit and the charging voltage application unit, wherein, in a case where a current value detected in a predetermined charging voltage application state is a second current value larger than a first current value, the control unit controls the exposure unit to perform image formation with a first exposure amount smaller than that in a case where the detected current value is the first current value.

Abstract: A photoconductive layer in an image forming apparatus is refreshed. A first refreshing cycle is performed, including applying, at a first refresh unit, a first refresh voltage to the photoconductive layer and applying, at a second refresh unit, a second refresh voltage to the photoconductive layer. A second refreshing cycle is performed, including applying, at the first refresh unit, a third refresh voltage to the photoconductive layer, the third refresh voltage being higher than the first refresh voltage and higher than the second refresh voltage. Each of the first and second refreshing cycles electrically bias the photoconductive layer to a refresh polarity opposite to a print polarity applied during a print routine of the image forming apparatus.

Abstract: With prior art static electricity distribution measuring devices, there has been the problem that it has not been possible to measure the amount of electrostatic charge over a wide range at high spatial resolution and quickly. In the present invention, there are provided: a detection unit 20 in which a plurality of sensors, provided upon a surface, move relatively along the surface of an electrostatically charged subject 100 to be measured, and detect potential changes generated by the distance to the surface of the measurement subject being changed; a reference distance measuring unit that measures the distance between the surface of the measurement subject and the surface of the detection unit; a distance adjustment unit that adjusts that distance so that it becomes a reference distance that is determined in advance; and a vibrating unit that causes the distance between the surface of the measurement subject and the surface of the detection unit to change upon a predetermined cycle.

Abstract: A charging bias output portion is controlled so that a direct-current component of a charging bias voltage reaches a target voltage value taking a first set time after output start. A transfer bias output portion is controlled so that output of a transfer bias is started after a first position of an image bearing member reaches a transfer position and before a second position reaches the transfer portion, and a transfer current reaches a target current value taking a second set time. The first position is a position of the image bearing member that passes through a charging portion between a charging member and the image bearing member at a timing when the output of the charging DC is started, and the second position is a position that passes through the charging portion at a timing when the charging DC reaches the target voltage value.

Abstract: In an image forming apparatus, a control unit performs a control to cause an exposing unit to expose a plurality of image bearing members at different times to form exposure regions on the plurality of image bearing members, to acquire results acquired by applying direct current voltage lower than discharge start voltage to a plurality of abutting members by an applying unit when the exposure regions pass by abutting parts against the abutting members and detected by a detecting unit, and to, based on the acquired results of the detections, acquire information regarding the surface potentials of the plurality of image bearing members.

Abstract: A control portion executes: a step of calculating a surface potential of an image bearing member charged by a charging member, to which a predetermined voltage is applied, and exposed to light by a predetermined exposure amount on the basis of a discharge start voltage between a measurement member and the image bearing member and calculating a correction value from a difference between a target value and calculated surface potential of the image bearing member; a step of correcting calculated surface potential of the image bearing member on the basis of the correction value; and a step of controlling at least one of the voltage applied to the charging member and an exposure amount of the exposure apparatus on the basis of the corrected surface potential of the image bearing member so that the surface potential of the image bearing member reaches the target value.

Abstract: An image forming apparatus includes an apparatus main body, a photoreceptor drum, a charging apparatus, an exposure apparatus, a developing device, a charging bias applying unit, a developing bias applying unit, an image condition adjusting unit, and a print density measurement unit. The image condition adjusting unit forms a second electric potential region by applying the charging bias where a first differential electric potential is subtracted from a first tentative charging bias on a circumference surface of a photoreceptor drum, and forms a second toner image by an electric potential difference between the second electric potential region and a developing roller by applying the target electric potential. The image condition adjusting unit decides value of the charging bias corresponding to the target electric potential from measurement results of print densities of a first toner image and the second toner image measured by the print density measurement unit.

Abstract: Voltages are applied to an image bearing member using at least three application voltage values which are larger than a discharge start voltage value and which have different magnitudes, at least one of the application voltage values having a value at which a direction of a current corresponding to the one of the application voltage values is reverse to those of currents corresponding to the other application voltage values. A relation between the application voltage value and the detection current value in a discharge area is calculated based on at least three application voltage values Vd1, Vd2, Vd3 and at least three detection current values Id1, Id2, Id3 detected by a current detection portion in relation to at least three application voltage values Vd1, Vd2, Vd3 and a voltage value V0 at which the detection current value is zero is calculated based on the relation in the discharge area.

Abstract: An image forming apparatus includes a latent image bearer; a charger; an exposure device; a developing device; a potential detector to detect a surface potential at a detection position between an exposure position and a development position on the latent image bearer in a direction of rotation of the latent image bearer; and a potential controller to determine an image forming condition. The potential controller includes a potential calculator to calculate an exposed area potential based on a detected potential smaller in charging polarity than a potential threshold, out of the detected surface potential, and a threshold determiner to set the potential threshold between the exposed area potential and an unexposed area potential of the latent image bearer based on at least one of a change in the unexposed area potential, a change with time of the latent image bearer, and a change in an ambient condition.

Abstract: An image forming apparatus includes a photosensitive member, an exposure device, a detection device, a measurement device that measures a current flowing to the detection device, and a control unit that executes a detection mode in which an electrostatic latent image is formed on the photosensitive member and the measurement device detects a change in the current relative to the electrostatic latent image, wherein, in an adjustment mode, the control unit causes a potential difference between the electrostatic latent image and the detection device to be smaller as a layer thickness of the photosensitive member is more reduced.

Abstract: An image forming apparatus includes: a charging member; a transfer member; a setting portion for setting a positive-side discharge start voltage when a positive-side voltage relative to a reference potential is applied to the transfer member after a voltage is applied to the charging member so that a surface of the image bearing member is charged to the reference potential by the charging member and for setting a negative-side discharge start voltage when a negative-side voltage relative to the reference potential is applied to the transfer member after the voltage is applied; a calculating portion for calculating a correction amount for correcting a light portion surface potential, of the image bearing member, calculated by the calculating portion on the basis of the positive-side and negative-side discharge start voltages; and a correcting portion for correcting the light portion surface potential by using the correction amount.

Abstract: An image forming apparatus includes a latent image carrier, a charging device, a latent image forming device, a developing device, a transfer device, a toner amount detector, and a control circuit to execute an imaging condition determination process. The control circuit obtains a linear approximation formula of a developing potential and an amount of toner according to an exposure potential of the patch pattern and a detected amount of toner to calculate a developing gamma and a developing start voltage according to a gradient of the linear approximation formula, determines target charging potential, exposure potential and developing bias according to the developing gamma and the developing start voltage, determines an amount of a background potential to be corrected according to a difference between the developing start voltage and a target developing start voltage obtained according to environmental information, and corrects the target charging potential.

Abstract: After a toner image is transferred from a photoreceptor to an intermediate transfer belt, a surface of the photoreceptor is destaticized by a static eraser including a plurality of light emitting elements arranged in an axial direction of the photoreceptor. A first density sensor and a second density sensor for detecting densities of toner applied to the intermediate transfer belt are provided at a position where a large quantity of light from the static eraser is applied to the photoreceptor surface and a position where a small quantity of light from the static eraser is applied to the photoreceptor surface. In a case where a density difference between the detected toner densities exceeds a predetermined threshold value, a destaticization controller carries out an additional destaticizing operation by the static eraser.

Abstract: A state determining device includes a current detecting unit, a state determining unit, and a notifying unit. The current detecting unit detects a current value of a drive current which flows into a drive motor that rotary-drives a driven unit with a drive force according to the drive current. Based on the drive current value detected by the current detecting unit, the state determining unit determines a state of a driving system including the driven unit. The notifying unit notifies a user of a determination result of the state determining unit.

Abstract: A method of measuring a total amount of latent image charge includes: scanning a sample with a charged particle beam, the sample having a charge distribution on a surface of the sample, the charge distribution being caused by forming an electrostatic latent image by exposure; measuring a state of a surface charge distribution on the sample based on a detection signal obtained by the scanning; obtaining an electric potential at a potential saddle point, the potential saddle point being formed by the surface charge distribution of the sample; obtaining an electrostatic latent image area, the electrostatic latent image being formed by the surface charge distribution of the sample; and performing a calculation using the electric potential at the potential saddle point and the electrostatic latent image area to measure a total amount of electric charge of the electrostatic latent image.

Abstract: An image forming apparatus configured to, in a state where a voltage is applied to a charging unit, determine a surface potential of an image bearing member using a first voltage applied when a current value obtained by, after applying a predetermined voltage to a transfer unit, detecting the current value while changing the applied voltage to a positive direction reaches a discharge current value, and a second voltage applied to the transfer unit when a current value obtained by, after applying the predetermined voltage to the transfer unit, detecting the current value while changing the applied voltage to a negative direction reaches the discharge current value.

Abstract: An image forming apparatus includes a rotatable image carrier that carries a toner image having a length corresponding to at least a circumferential length of the carrier; an image density detector that detects a density of the image; a potential detector that detects, over at least the circumferential length, a surface potential of the carrier before toner adheres thereto; a first image forming device that adjusts the density with a first factor, and forms an image based on a first condition of the first factor; a second image forming device that adjusts the density with a second factor, and forms an image based on a second condition of the second factor; a first determining device that determines the first condition based on uneven density; and a second determining device that determines the second condition based on uneven density and a potential distribution of the surface potential.

Abstract: An image forming apparatus configured to, in a state where a voltage is applied to a charging unit, determine a surface potential of an image bearing member using a first voltage applied when a current value obtained by, after applying a predetermined voltage to a transfer unit, detecting the current value while changing the applied voltage to a positive direction reaches a discharge current value, and a second voltage applied to the transfer unit when a current value obtained by, after applying the predetermined voltage to the transfer unit, detecting the current value while changing the applied voltage to a negative direction reaches the discharge current value.

Abstract: An image forming apparatus includes a deterioration determining device to determine a deterioration degree of a latent image bearer based on a potential detected by a surface potential detector. The deterioration determining device calculates a relative value indicating the deterioration degree based on the aggregated number of pixels and a time value for each of virtually divided regions. The deterioration determining device determines a deterioration degree of a detecting target region of the virtually divided region based on a potential detected by the surface potential detector. The deterioration determining device further determines deterioration degrees of non-detecting target respective regions of the virtually divided regions based on the relative values of the non-detecting target respective regions, the relative value of the detecting target region, and the deterioration degree of the detecting target region.

Abstract: In a method to determine an electrical potential at a predetermined point on a surface of a photoconductor rotating with process speed in an electrophotografic printer, a charge reversal station is arranged at the photoconductor to reverse a charge of the photoconductor. A potential measurement probe is provided adjacent to the photoconductor to measure a potential at the photoconductor. The photoconductor is operated with a speed reduced from the process speed in a ratio of a distance between the charge reversal station and the potential measurement probe and the distance between the charge reversal station and the predetermined point. The potential at the photoconductor is measured via the potential measurement probe which creates a measurement value at the reduced speed. The photoconductor is accelerated to the process speed. The measurement value of the potential measurement probe is used as the electrical potential at the predetermined point.

Abstract: The image forming apparatus includes an image carrier, a developer carrier, a magnetic field generation unit that is fixedly disposed in a hollow part of the developer carrier and includes a plurality of magnetic poles disposed in a circumferential direction of the developer carrier, a conductive member disposed so as to oppose a predetermined magnetic pole, of the plurality of magnetic poles, which is located odd-number pole upstream of a magnetic pole corresponding to a developing area D in a rotational direction of the developer carrier, a power source that can apply a voltage to the conductive member, a potential detection unit configured to detect pre-development and post-development potentials of a predetermined image formed on the image carrier, and a changing unit configured to change the voltage to be applied from the power source to the conductive member based on a detection result obtained by the potential detection unit.

Abstract: In a method to determine an electrical potential at a predetermined point on a surface of a photoconductor rotating with process speed in an electrophotografic printer, a charge reversal station is arranged at the photoconductor to reverse a charge of the photoconductor. A potential measurement probe is provided adjacent to the photoconductor to measure a potential at the photoconductor. The photoconductor is operated with a speed reduced from the process speed in a ratio of a distance between the charge reversal station and the potential measurement probe and the distance between the charge reversal station and the predetermined point. The potential at the photoconductor is measured via the potential measurement probe which creates a measurement value at the reduced speed. The photoconductor is accelerated to the process speed. The measurement value of the potential measurement probe is used as the electrical potential at the predetermined point.

Abstract: The high-voltage output apparatus includes a voltage application part that applies a DC voltage to the charge member; a current detection part that detects a value of a current flowing in the image bearing member when the DC voltage is applied to the charge member; and a control part that calculates a plurality of discharge start voltages for the image bearing member, based on a plurality of current values detected by the current detection part as a result of the voltage application part applying a plurality of different DC voltages to the charge member, and controls the DC voltage applied to the charge member, using the plurality of calculated discharge start voltages. Consequently, a high-quality image can be formed by maintaining a potential on a photosensitive drum to be constant irrespective of the states of the circumstances and/or the drum layer thickness.

Abstract: A cleaning device includes a cleaning roller which contacts an intermediate transfer belt for carrying an image developed using a liquid developer, a cleaning roller which contacts the other cleaning roller and has a greater axial length than the other cleaning roller, and a rubber blade which contacts the cleaning roller and has a greater axial length than the cleaning roller.

Abstract: This disclosure provides methods and systems for troubleshooting charging and photoreceptor failure modes associated with a xerographic process. Specifically, according to an exemplary method the photoreceptor decay behavior, with and without the effects of depletion, are quantified and used to determine a performance state of one or more of the charging stations and the photoreceptor surface.

Abstract: An image forming apparatus includes a sheet-type determining unit that determines a sheet type of a recording sheet; a sheet-characteristic measuring unit that measures a sheet characteristic of the recording sheet; an image processing unit that performs an image processing on image data of an image for adjusting a consumption amount of color material that is used for forming the image on the recording sheet based on the sheet type and the sheet characteristic; and an image forming unit that forms the image of the image data processed by the image processing unit on the recording sheet.

Abstract: Non-uniformity of a rotatable electrophotographic imaging component is compensated. The component has an intentional periodic variation that produces density variations in a test target. The angular position on the component of the intentional variation is correlated with the amount of an unintentional variation at several points to produce a non-uniformity map. An image signal with multiple regions of data is received. For each region, the angular position of the intentional variation in that region is determined, and the non-uniformity map is used to determine the correction required for the unintentional variation. The image data in the region are adjusted to compensate, and corresponding toner is deposited.

Abstract: The high-voltage output apparatus includes a voltage application part that applies a DC voltage to the charge member; a current detection part that detects a value of a current flowing in the image bearing member when the DC voltage is applied to the charge member; and a control part that calculates a plurality of discharge start voltages for the image bearing member, based on a plurality of current values detected by the current detection part as a result of the voltage application part applying a plurality of different DC voltages to the charge member, and controls the DC voltage applied to the charge member, using the plurality of calculated discharge start voltages. Consequently, a high-quality image can be formed by maintaining a potential on a photosensitive drum to be constant irrespective of the states of the circumstances and/or the drum layer thickness.

Abstract: The image forming apparatus calculates a surface voltage of an image bearing member based on a first charge start voltage, which is obtained when a first voltage application section applies a first DC voltage to a charge section, and a second charge start voltage, which is obtained when a second voltage application section applies a second DC voltage to the charge section. This allows a high-quality image to be formed irrespective of a change in circumstance or drum layer thickness.

Abstract: An image forming apparatus includes a rotatable image carrier that carries a toner image having a length corresponding to at least a circumferential length of the carrier; an image density detector that detects a density of the image; a potential detector that detects, over at least the circumferential length, a surface potential of the carrier before toner adheres thereto; a first image forming device that adjusts the density with a first factor, and forms an image based on a first condition of the first factor; a second image forming device that adjusts the density with a second factor, and forms an image based on a second condition of the second factor; a first determining device that determines the first condition based on uneven density; and a second determining device that determines the second condition based on uneven density and a potential distribution of the surface potential.

Abstract: A method of measuring a total amount of latent image charge includes: scanning a sample with a charged particle beam, the sample having a charge distribution on a surface of the sample, the charge distribution being caused by forming an electrostatic latent image by exposure; measuring a state of a surface charge distribution on the sample based on a detection signal obtained by the scanning; obtaining an electric potential at a potential saddle point, the potential saddle point being formed by the surface charge distribution of the sample; obtaining an electrostatic latent image area, the electrostatic latent image being formed by the surface charge distribution of the sample; and performing a calculation using the electric potential at the potential saddle point and the electrostatic latent image area to measure a total amount of electric charge of the electrostatic latent image.

Abstract: An image forming apparatus configured to, in a state where a voltage is applied to a charging unit, determine a surface potential of an image bearing member using a first voltage applied when a current value obtained by, after applying a predetermined voltage to a transfer unit, detecting the current value while changing the applied voltage to a positive direction reaches a discharge current value, and a second voltage applied to the transfer unit when a current value obtained by, after applying the predetermined voltage to the transfer unit, detecting the current value while changing the applied voltage to a negative direction reaches the discharge current value.

Abstract: A toner image height measurement apparatus capable of accurately measuring heights of toner images of respective colors with a relatively simple construction and without being affected by toner colors. With motion of an image carrier, there occurs a change in reflection light amount detected by a photodiode of the height measurement apparatus in timing when laser light having been irradiated onto the image carrier starts to be irradiated onto or intercepted by a toner image and in timing when the laser light having been irradiated onto the toner image starts to be irradiated onto the image carrier. Based on a principle that these timings vary according to a toner image height, the height measurement apparatus detects the timing when the reflection light amount changes by a predetermined amount, thereby detecting the toner image height.

Abstract: Disclosed herein is an image forming apparatus capable of avoiding positional interference between an electrical potential sensor and a developing device during the installation or separation of the developing device. The positional interference is prevented by moving the electrical potential sensor out of the movement path of the developing device in association with the opening/closing movement a cover for an access opening in the body of the image forming apparatus for the installation/separation of the developing device. A link device connects the cover and the electrical potential sensor to each other so as to cause the movement of the electrical potential sensor in linkage with the opening/closing of the cover. The link device serves as an anti-interference device that prevents the positional interference between the developing device and the electrical potential sensor.

Abstract: The transfer of a duplicate electronic document between image forming devices is done with an electronic document that is formed of only resolution-independent vector data and the like, and a normal printing of the duplicate electronic document or printing of different resolution is performed by developing the vector data. In high-quality printing of the duplicate electronic document, a Fill Map included in the original document the information indicating the location of an electronic document of copy source that is embedded in a metadata specifies is obtained, and this printing is made using the Fill Map.

Abstract: A potential sensor for detecting a surface potential of an electrophotographic photosensitive member includes an insulative film; a thin film electrode layer formed on the film; a curved portion formed by folding back the film so that the thin film electrode layer is inwardly located, the curved potion functioning as a detecting portion for detecting the surface potential of the electrophotographic photosensitive member in contact with the electrophotographic photosensitive member; and an electroconductive shielding portion provided so as to cover an outer surface of the film except for at least an area in which the curved portion is contactable to the electrophotographic photosensitive member, the shielding portion being electrically grounded.

Abstract: An image forming apparatus including a latent image carrier, a charger to evenly charge a surface of the latent image carrier, a writing device to irradiate a charged surface of the latent image carrier to form an electrostatic latent image, a writing device control unit to control the writing device, a developing device to develop the electrostatic latent image to form a toner image, a transfer device to transfer the toner image onto a transferred member, and a pre-transfer irradiating device to irradiate the charged surface of the latent image carrier during a period after development and before transfer. The writing device control unit controls the writing device based on a target image signal A and an image signal B output a single rotation of the latent image carrier after output of the target image signal A in a sub-scanning direction.

Abstract: An image forming apparatus which makes it possible to resolve correction error of potential unevenness caused by insufficient mounting accuracy of an image carrier, in a relatively short time period without performing a conventional operation for removing the image carrier. The image forming apparatus includes a photosensitive drum, an exposure unit, an electrical potential sensor, a shading data ROM, and a CPU. Electrical potential data items associated with respective positions on the surface of the photosensitive drum are stored in the shading data ROM. The CPU corrects an exposure amount onto the photosensitive drum by the exposure unit, based on the electrical potential data read from the ROM, and based on the result of correction, adjusts timing for reading out the data.

Abstract: An image forming apparatus including a photosensitive body, a charger configured to charge the photosensitive body, an exposure unit configured to expose the photosensitive body charged by the charger, a developer transport section configured to cause relative movement with respect to the photosensitive body for transporting developer therebetween, a current measurement section configured to measure a current flowing between the photosensitive body and the developer transport section, and a determination unit configured to compare a current with a threshold, the current measured by the current measurement section when the photosensitive body and the developer transport section move relatively to each other and a first area of the photosensitive body that needs to be exposed faces the developer transport section, and determine whether an exposure of the photosensitive body is proper based on a result of the comparison.

Abstract: An image forming apparatus includes a photosensitive member; a charging member contactable to said photosensitive member to electrically charge said photosensitive member; applying means applying a charging bias voltage to said charging member; detecting means detecting a current flowing between said charging member and said photosensitive member; a controller for controlling said image forming apparatus to execute an operational mode for removing an electric discharge product deposited on a surface of said photosensitive member, in the case that detecting means detects a current not lower than a predetermined value when a voltage lower than a voltage at which an electric charge starts between said photosensitive member and said charging member is applied to said charging member.

Abstract: There is provided an image forming apparatus and method capable of reducing a measurement error in a measurement result of the surface potential of an electrostatic latent image formed on the surface of an image bearing member. The measurement error occurs under the influence of an electric field generated from a pre-exposed area. Consequently, miniaturization of an image forming apparatus and consistent print quality can be achieved. The image forming apparatus includes an image forming control section for determining an error correction value corresponding to the charge state of a latent image on the basis of relationships between charge states of the latent image and error correction values which have been prepared in advance, computing an error corrected potential measurement value using the error correction value and a potential measurement value, and controlling the image forming apparatus on the basis of the error corrected potential measurement value.