Abstract: An image forming apparatus includes a plurality of image forming stations. In each image forming station an electrostatic latent image carrier and a charging member are arranged to face each other with a specified gap therebetween. A charging failure caused by an abnormal discharge in the gap is detected based on a current detection result by a current sensor, and an image forming station having an abnormality is reliably specified.

Abstract: A method and an apparatus of controlling a charge voltage including the steps of applying, charging, detecting, and determining. The applying step applies an application voltage having a direct-current voltage and an alternating-current voltage superimposed onto the direct-current voltage to a charge-applying member to charge a charge carrier. The changing step charges the alternating-current voltage of the application voltage. The detecting step detects an alternating current flowing through the charge carrier when the charge-applying member applies the application voltage to the charge carrier. The determining step determines a value of the alternating-current voltage of the application voltage based on at least two alternating currents detected by the alternating-current detector.

Abstract: An image forming apparatus which predicts VL fluctuations of a photosensitive drum in consideration of a double-sided print mode, and performs an image formation control based on the prediction, and thus always obtains a stable density image. The image forming apparatus performs an appropriate image formation control by controlling an image forming condition based on a photosensitive member rotation time, a photosensitive member stop time, a temperature of an atmospheric environment, an absolute humidity of the atmospheric environment, and whether an image formation that precedes a subsequent image formation is performed in single-sided printing or double-sided printing.

Abstract: Provided are an image forming apparatus and a method of forming a color image using the same. The image forming apparatus includes: an image forming medium forming a latent image and having a plurality of cells, wherein each cell operates independently and the cells are charged according to a color image to be recorded; a developing unit developing the latent image into the color image and comprising a plurality of toner cartridges containing different color toners, wherein the toner cartridges are aligned around the image forming medium and spaced apart from each other at predetermined intervals; a transferring unit transferring the color image to a recording medium; and a fixing unit fixing the color image that has been transferred to the recording medium, wherein, as the cells face the toner cartridges, the amount of charge applied to the cells is gradually increased and different color toners overlap on the cells, so that the latent image is developed into the color image.

Abstract: A reference developing image is formed on a photoreceptor drum under an image forming condition measured in advance, and the density of this reference developing image is detected. A development bias voltage is corrected based on the detection result, and when a correction value of the development bias voltage exceeds a predetermined range, a reference output voltage of an ATC sensor for detecting the density of toner in a developing device is corrected based on the detected value of humidity around the developing device, the frequency of use of the apparatus, and the agitation stress of developer.

Abstract: An image forming apparatus including a latent image bearing member a surface of which is rotated, a charging device, an irradiating device, a developing device, a transfer device, and a control unit. The control unit controls the image forming apparatus to perform subsequent image formation in accordance with a subsequent image forming request when determining that the subsequent image forming request is present at a predetermined determination time after completion of previous image formation, and controls the image forming apparatus to shut down certain predetermined operations including at least rotation of the surface of the latent image bearing member and application of a charging bias from the charging device and a developing bias from the developing device in accordance with a predetermined shutdown sequence when determining that the subsequent image forming request is not present at the predetermined determination time.

Abstract: An electrostatic charging apparatus, includes: an endless-shaped electrostatic charging belt having electrical conductivity, the electrostatic charging belt being arranged in a state of having a predetermined contact zone being in contact with a moving to-be-charged body and moving in the same direction as a moving direction of the to-be-charged body; and plural electrode members including at least a first electrode member and a second electrode member, the plural electrode members being provided inside the electrostatic charging belt, and the first and second electrode members being provided on both sides of the contact zone of the electrostatic charging belt in the moving direction thereof so as to press the electrostatic charging belt against the to-be-charged body and forming gaps that permit electric discharge between the to-be-charged body and the electrostatic charging belt, the gaps being adjacent to the respective sides of the contact zone of the electrostatic charging belt.

Abstract: An image forming apparatus including an image carrier that includes a photoconductive layer on which an electrostatic latent image is formed, a charging member that comes in contact with the image carrier and charges the photoconductive layer, and a feeding section that supplies a current to the charging member by applying a vibration voltage with an alternate current component superposed on a direct current component, wherein the alternate current component may contain a first amplitude that eliminates charging non-uniformity when the vibration voltage is applied with a uniform amplitude and a second amplitude that is smaller than the first amplitude.

Abstract: An image forming apparatus comprises an image carrier configured to hold a developing agent image; a transfer unit that transfers the developing agent image to a recording medium; a first application unit that controls a transfer voltage applied to the transfer unit; a recovery unit that recovers the developing agent remaining on the image carrier; a second application unit that controls a recovery voltage applied to the recovery unit; a determination unit that determines whether or not a recovery current flowing between the image carrier and the recovery unit exceeds a first predetermined current value; and a control unit that, when the determination unit makes a positive determination that the recovery current has exceeded the first predetermined current value, performs a protective control for controlling the first application unit such that a transfer current flowing between the image carrier and the transfer unit becomes greater.

Abstract: An image forming apparatus includes an auxiliary charging member contacting an image bearing member and for being supplied with a bias of an identical polarity to a normal charge polarity of toner at a position downstream from a transfer portion where a transfer member is located and upstream from a charging portion where a charging member is located with respect to a rotation direction of the image bearing member. When rotation of the image bearing member is stopped and then resumed, application of a toner transfer bias to the transfer member is started before a contact position between the image bearing member and the auxiliary charging member during the rotation stop of the image bearing member first reaches the transfer portion.

Abstract: A method for determining a location of an uncharged region on a photoconductive drum in an electrophotographic device, including rotating the photoconductive drum, and charging a surface of the drum via a charge roller by application of a voltage to the charge roller. An electrical characteristic of one of the charge roller or photoconductive drum is measured, and an alteration in the electrical characteristic is used to determine a location of the uncharged region.

Abstract: Data associated with printing on the sides of sheets subjected to printing by a printing apparatus are managed in the print order. The data associated with printing on the sides are output to the printing apparatus in the print order.

Abstract: A xerographic marking engine adjusts a charging actuator, such as an AC peak-to-peak voltage or an AC peak-to-peak AC current, based upon toner patch density measurements made using, e.g., a toner patch density sensor. The sensor is used to detect a knee in a toner mass density curve obtained by sweeping an AC peak-to-peak voltage or an AC peak-to-peak current. Once the knee is located, an AC charging actuator peak-to-peak voltage or AC peak-to-peak current is determined that reduces the amount of positive charge that is deposited onto the surface of the photoconductor, thereby extending its life while maintaining acceptable print quality. The described approach may improve photoconductor life without significantly increasing production costs or complexity.

Abstract: An apparatus includes an image bearing member for carrying an image; an intermediary transfer member for receiving the image; a primary transfer member for transfer of the image onto the intermediary transfer member in a primary transfer station; a secondary transfer member for transfer of the image onto a transfer material in a secondary transfer station; a first charging member for charging toner remaining in a region upstream of the primary transfer station and downstream of the secondary transfer station; and a second charging member for charging the toner remaining in a region upstream of the primary transfer station and downstream of the first charging member. The first charging member rubs a surface of, and the second charging member moves in contact with, the intermediary transfer member, to transfer the toner remaining on the intermediary transfer member to the image bearing member simultaneously with the primary transfer.

Abstract: An image forming apparatus uses a charging roller to charge the surface of a photosensitive member to a predetermined potential. A current detector detects charging current when the charging bias is applied. A bias corrector corrects the charging bias and a storage stores a target charging current value when the photosensitive member is charged to a required potential. The bias corrector performs two corrections. The first correction compares a charging current value with a stored target charging current value, and determines a new bias based on the comparison. The second correction determines whether the bias obtained by the first correction is at a predetermined level or a higher level, and when the corrected charging bias is at the higher level, changes the target charging current value in accordance with the corrected charging bias and obtains a new charging bias on the basis of the changed target charging current value.

Abstract: An image density in a predetermined section of an image represented by an image signal is calculated on the basis of the image signal, and the calculated image density is compared with the result of detection of a density in the predetermined section of a toner image formed on the basis of the image signal. Then, it is determined whether or not to perform a density-adjusting process in which an image-density adjustment is performed on the basis of correction pattern data. Thus, the density adjustment is performed at a suitable timing while monitoring the density of images formed in a normal image-forming operation.

Abstract: To provide: a charge control agent having negative chargeability, which contributes to environmental conservation and the like to an increased degree, has high performance (high charge amount, quick rise-up of charge, excellent stability with time, and high environmental stability), and has improved dispersibility; a toner for developing an electrostatic charge image containing the charge control agent; and an image forming method and an image forming apparatus each using the toner for developing an electrostatic charge image. A charge control agent for controlling a charged state of powder, characterized by including one or more units each represented by the following chemical formula (1) in a molecule.

Abstract: An image forming apparatus capable of detecting a resistance value of an intermediate transferring member at a stabilized sensitivity irrespective of the influences of environmental conditions, disturbing elements, etc. and contributing to the promotion of the image quality when forming images. The image forming apparatus is equipped with an electric potential controller to fix electric potential of the photosensitive surface of a photosensitive drum, a power source to supply a prescribed voltage or current to the photosensitive surface through the transferring surface of an intermediate transferring member, and a resistance detector to detect a current value flowing through the intermediate transferring member against a prescribed voltage supplied from the power source or a voltage value generated in an intermediate transferring member against a prescribed current and detect a resistance value of the intermediate transferring member based on the detected current value or voltage value.

Abstract: An apparatus for forming a multi-color is disclosed which includes a controller that performs an anti reverse-transfer control such that a surface potential of a previously-formed separated-developer-image subset of a plurality of single-color separated-developer-images which has been previously transferred onto an image transferred medium is reduced, prior to a subsequent transfer in which a remainder of the plurality of separated-developer-images is transferred onto the image transferred medium after a previous transfer of the previously-formed separated developer-image subset onto the image transferred medium, to thereby prevent a reverse transfer of a part of a developer material on the image transferred medium from the image transferred medium onto a photoconductor at the subsequent transfer.

Abstract: An image forming apparatus includes a standard exposure device (1) adjusted to emit light of a predetermined light quantity, and a control device configured to determine light quantity of the pre-charge exposure device in an image-forming period based on the first and the second charging current values, wherein first charging current value is detected when an area on a photosensitive member surface is recharged by the contact charging member, in a case where the photosensitive member is exposed by turning on the standard exposure device without turning on a pre-charge exposure device, and second charging current value is detected when an area on the photosensitive member surface is recharged by the contact charging member, in a case where the photosensitive member charged by applying a predetermined voltage by the contact charging member is exposed by turning on the pre-charge exposure device without turning on the standard exposure device.

Abstract: A charging device includes a charging member that charges a body to be charged; a detector that detects an AC component of a current flowing through the charging member; an integration section that integrates the AC component of the current detected by the detector; a controller that controls the current flowing through the charging member, according to a result of integration executed by the integration section; a periodic signal generating section that generates a periodic signal having a cycle period corresponding to a cycle period of the AC component; and an integration period adjusting section that adjusts a period of integration executed by the integration section, with reference to the periodic signal.

Abstract: A charging unit available in a process unit detachably attached to an image forming apparatus includes a charging member configured to uniformly charge a surface of an image carrying member while contacting the image carrying member, and a charge bias applying unit configured to apply a charge bias superimposing a direct current voltage on an alternating current voltage to the charging member. The alternating current voltage satisfies a relational expression of “Vpp×0.4/t?8.8×103”, “Vpp” representing a peak-to-peak voltage of the alternating current voltage in the charge bias, and “t” representing a time period from a first point of a swing of a wave component starting to swing by a large amount to a same polarity as the direct current voltage of the charge bias to a second point of the swing of the wave component reaching approximately 80% of an amplitude of the wave component.

Abstract: An image forming apparatus is provided capable of preventing fog from happening and obtaining more stable image density, which includes an image carrier; a charging section for charging surface of the image carrier; an exposing section for forming an electrostatic latent image on the image carrier; a developing section for making developer adhere to the electrostatic latent image formed on the image carrier so as to form a visible image; a transferring section to transfer the visible image onto a transfer member; a density detecting section to detect a density of the visible image; a development voltage setting section to set a development; a charge voltage setting section to set a difference between the charge voltage and the development into a value in a predetermined range; and an exposure quantity setting section to set an appointed exposure quantity with respect to the charge voltage.

Abstract: An image formation apparatus is provided and includes: a photoconductor; a charging section that applies a bias voltage having an AC voltage superposed on a DC voltage to the photoconductor so as to charge the photoconductor; a controller that controls at least one of the AC voltage and an AC current in response to a fluctuation amount of a DC current flowing between the photoconductor and the charging section when an AC voltage is applied; and a detector that detects the DC current.

Abstract: An image forming apparatus includes a photoreceptor having on a surface thereof a photosensitive layer, in which an electrostatic latent image is formed, a contact charging roll applied with a bias containing a direct current component having superimposed thereon an alternating current component, the contact charging roll charging the photoreceptor to a predetermined potential, a film thickness detecting unit detecting a film thickness of the photosensitive layer of the photoreceptor, an environment detecting unit detecting environment, and a contact area changing unit changing a contact area between the contact charging roll and the photoreceptor based on detected results of the film thickness detecting unit and the environment detecting unit.

Abstract: An image forming device includes: a high voltage generating circuit for applying an oscillating voltage to a charging member disposed in contact with or proximity to an image carrier, the oscillating voltage having a DC voltage Vdc and an AC voltage Vac superimposed thereon; a current detecting portion for detecting the value of a DC current Idc between the image carrier and the charging member; an AC voltage control portion for controlling the value of the AC voltage Vac so as to secure the detected value of the DC current Idc within a target current range; and an aging control portion for performing rotation driving of the image carrier while securing the AC voltage Vac and the DC voltage Vdc at preset voltage values and setting the frequency of the AC voltage Vac at a frequency different from a frequency during an image forming operation.

Abstract: A method of controlling AC voltages applied to a charging member to bring a photoreceptor to a state of uniform charging, with reduced time required for setting AC voltage value. The method includes the steps of determining a relational expression between AC voltage and AC current flowing into the charge receptor member using a discharge onset voltage Vth, a first detection current flowing into the charge receptor member under a first AC voltage of 2×Vth or larger, a second detection current under a second AC voltage, which is 2×Vth or larger and different from the first AC voltage; and obtaining a third AC voltage by substituting a predetermined standard AC current value into the relational expression. When the third AC current under the third AC voltage, which is actually applied to the charging member, is within a predetermined range, the third AC voltage is set as the AC voltage to be applied to the charging member.

Abstract: Charging devices, electrostatic imaging devices, and methods generate a charging waveform having a DC bias component and an AC component for charging the imaging surface of a charge retentive member, the AC component having a substantially squarewave waveform.

Abstract: A charging system for uniformly charging an imaging surface moving in a predefined path including a dicorotron for charging the imaging surface; a discorotron, adjacent to and downstream from said dicortron, for charging the imaging surface; the discorotron including a coronode, a grid and a shield a first power supply for biasing the grid and the shield; a second power supply for energizing each of the coronode; means for determining a voltage level of the imaging surface and generating a feedback signal of the voltage level; and a controller, responsive to the feedback signal and in communication with the first power supply, for controlling the energiziation of the grid and the shield.

Abstract: Embodiments of an electrophotography device are disclosed.

Abstract: In an image forming apparatus, temporary constant voltages are not by using three voltage-current data obtained by applying voltages at three levels to a primary transfer roller to detect currents corresponding to the voltages, respectively. A surface potential of a photosensitive drum is detected by a potential sensor by changing an exposure intensity of an exposure device at three levels in a state in which the temporary constant voltage is applied to the primary transfer roller. A constant voltage during image formation is determined by correcting the temporary constant voltage by using three voltage-current data obtained by detecting currents when surfaces different in potential by light exposure pass through a primary transfer portion.

Abstract: An image forming apparatus includes a photosensitive member; a charging device for charging the photosensitive member; an exposure device for exposing the photosensitive member charged by the charging device in accordance with image information; a developing device for developing, with toner, an electrostatic image formed on the photosensitive member by the exposure device into a toner image; a transfer charger for transferring the toner image formed on the photosensitive member by the developing device onto an image receiving member in a transfer portion; a light discharger, provided between the transfer charger and the charging device with respect to a rotational direction of the photosensitive member, for electrically discharging by light the photosensitive member; a current detector for detecting a current flowing through the transfer charger; a corrector for correcting a charging bias voltage applied to the charging device on the basis of an output of the current detector provided when a portion of the p

Abstract: A storage stores data of charging electric potentials at two or more points on a surface of an image carrier, and coordinates thereof expressed using a main-scanning position and a sub-scanning position thereof. A determination unit determines a correction value of a light power from the data of charging electric potentials at two or more points and coordinates thereof that have been read out from the storage unit. The correction value is applied to the light source so as to reduce the charging electric potential or the charging electric potential unevenness of coordinates on the surface of the image carrier. A correction unit uses the determined charging electric potential or correction value to correct the light power of the light source so as to mitigate an influence of charging unevenness at each set of coordinates.

Abstract: An image forming apparatus includes a photoconductor, a transfer roller, and a power supply for providing a voltage signal for the transfer roller to transfer surface attachments on the transfer roller to the photoconductor. Moreover, before providing the voltage signal for the transfer roller, a surface voltage level of the photoconductor can be adjusted according to the voltage signal in order to ensure that the surface voltage level of the photo conductor can be kept in a safe charging range. Therefore, the transferring efficiency of the transfer roller is ensured and damage to the photo conductor is prevented.

Abstract: An image forming apparatus including an image bearing member, a charging member, and a measuring member. The image forming member is configured to bear an image. The charging member is configured to charge a surface of the image bearing member when a direct current bias voltage is added to at least an alternating bias voltage which is applied to the charging member, and has a frequency fc of the alternating bias voltage. The measuring member is configured to measure a potential of the surface of the image bearing member, and has a drive frequency fvsen. The relationship of the frequency fc and the drive frequency fvsen is expressed as fc?fvsen×n and fc×n?fvsen.

Abstract: The invention provides an image forming apparatus having: an image holding member; an image holding member; a charging unit; a latent image-forming unit; a development unit; a measuring unit; and a control unit. The image holding member has a substrate having a surface having regular reflectance in a range of about 30% to about 95% with respect to light having a first wavelength and a subbing layer having a light transmittance of about 50% or greater per unit thickness of the layer with respect to light having the first wavelength and a photosensitive layer having absorption with respect to light having a second wavelength that is different from the first wavelength.

Abstract: A charging apparatus which is excellent in charging uniformity and thus allows a to-be-charged body to be charged uniformly and in which the generation of discharge products can be reduced, is provided. In the charging apparatus, ions are generated under the difference in electrical potential between the discharge electrode and the induction electrode produced in the ion generating section. The generated ions are caused to flow toward the counter electrode, whereupon the to-be-charged body arranged between the ion generating section and the counter electrode is charged.

Abstract: In a charging device of the present invention, with reference to a state (movement speed of a charging receiving material, operating period of charging device) in which the charging device is used which state is obtained by an image formation controlling section, a voltage controlling section sets or changes an applied voltage to be applied between a discharge electrode and an inductive electrode. Accordingly, even in a case where discharge is hard to occur, a necessary amount of ions can be supplied stably.

Abstract: In an electrographic printing device, an image generating system generates an electrical charge image on an image carrier element. The electronic charge image is made visible by a developer station via charged ink particles, the image being subsequently transferred onto a final image medium and fixed thereon. A speed control is provided which: continuously varies speed of the image carrier element from zero up to a limit speed; adapts charge intensity of the image carrier element to its speed; adapts an exposure intensity for exposure according to the image and in a deletion exposure of the image carrier element to its speed; and keeps a supply of toner to the image carrier element constant per area.

Abstract: A total layer thickness detection apparatus for a charged body includes: a saturated charge amount detection unit that detects a saturated charge amount of a charged body having plural coating layers with mutually different relative dielectric constants; a storage unit that stores relation information indicating relation of change of the saturated charge amount of the charged body with respect to a change of layer thickness of a surface layer of the charged body; and a calculation part that calculates a total layer thickness of the plural coating layers of the charged body based on the change of the saturated charge amount detected by the saturated charge amount detection unit and the relation information stored in the storage unit.

Abstract: A printer 20 includes a photosensitive drum 1, a charge roller 2 for electrically charging the photosensitive drum 1, a developing device 4 for developing an electrostatic latent image on the photosensitive drum 1 into a toner image, a transfer roller 5 for transferring the toner image onto a recording material, and a transfer residual toner charging member 8 for electrically charging toner remaining on the photosensitive drum 1.

Abstract: An image forming apparatus includes a high voltage generating circuit 91 that applies an oscillating voltage in which a DC voltage and an AC voltage are superimposed on each other, to a charging member 42 disposed in contact with an image carrier 41; a voltage control portion 96 that controls a peak-to-peak voltage of the AC voltage to a target voltage value; and an initial voltage adjusting portion 95 that sets a target voltage value based on a DC current value between the image carrier 41 and the charging member 42 which is detected by a current detecting portion 92. When an environmental condition which is used when the target voltage value is set changes, the initial voltage adjusting portion 95 performs an interrupt operation during an image forming process.

Abstract: An image forming apparatus including an image bearing member the moving surface of which travels, a charging device including a charging member located facing the moving surface of the image bearing member, which uniformly charges the moving surface of the image bearing member to form a latent electrostatic image thereon by applying a charging bias in which an AC voltage is overlapped with a DC voltage to the charging member, a developing device to develop the latent electrostatic image with toner to form a toner image on the moving surface of the image bearing member, a transfer device to transfer the toner image on the moving surface of the image bearing member to a recording medium, a fixing device to fix the toner image on the recording medium, an image formation speed switching device to switch from one image formation speed to another image formation speed among multiple image formation speeds by changing a surface traveling speed of the image bearing member according to a particular switching condition

Abstract: Provided is an electro-photographic image forming apparatus and a method of determining a charging voltage thereof. The electro-photographic image forming apparatus includes: a charge roller for supplying a voltage of a predetermined level to a photoconductor; a transfer roller for transferring a developed image to a printing media by using a developer; a high voltage power supply for supplying a charging voltage at a preset level and a transfer voltage at a preset level to the charge roller and the transfer roller, respectively; and a controller for predicting a charged electric potential deviation based on the transfer voltage to be supplied by the high voltage power supply and for determining a charging voltage level to correct for the predicted charged electric potential deviation. Therefore, the deviation of the charged electric potential caused by the transfer voltage is prevented.

Abstract: An image forming apparatus capable of varying a transferring force according to an amount of developer, thereby improving transfer quality, and a control method thereof. The image forming apparatus includes a plurality of photoconductive media on which electrostatic latent images are formed, a transfer unit onto which color developer images respectively developed on the plurality of photoconductive media are transferred and superimposed in sequence, and a controller to control in a manner that electric potential differences between image areas and non-image areas of the electrostatic latent images vary in an order in which the color developer images are transferred.

Abstract: An image forming apparatus includes a rotatable photosensitive drum, a charging apparatus to which a charging voltage is applied, an exposure apparatus forming an electrostatic image, a developing apparatus to which a development voltage is applied, a timer measuring an image formation time lapsed from start of rotation of the photosensitive drum and an image formation stop time lapsed from stop of the rotation of the photosensitive drum, and a temperature and humidity sensor detecting a temperature and a humidity of an atmosphere environment around the photosensitive drum. When the humidity is low, a charging voltage is controlled based on a measured result of the timer and detected results of the temperature and humidity sensor. When the humidity is high, the charging voltage is controlled based on the measured result of the timer and the temperature detected result of the temperature and humidity sensor without using humidity information.

Abstract: An image forming apparatus includes a rotatable image bearing member on which an electrostatic latent image is formed, a charging member, and a transfer member. A charging potential of the charging member is different between when the charging member provides a first region on the image bearing member with a potential and when the charging member provides a second region on the image bearing member with a potential, thus providing a predetermined potential difference between the first region and the second region. A third region on the image bearing member, with the transfer member being supplied with a voltage to provide a predetermined potential difference between a potential of the third region before being charged by the charging member and a potential of the third region after being charged by the charging member.

Abstract: An image forming apparatus includes an image bearing member; a plurality of chargers for injection charging of the image bearing member; a latent image forming device, disposed downstream of the plurality of charging members with respect to a moving direction of a peripheral surface of the image bearing member, for forming a latent image on the image bearing member having been charged by the plurality of charging members; a potential detecting device for detecting a surface potential of the image bearing member after passing by the plurality of charging members, wherein the plurality of chargers include a first charger and a second charger disposed at a most downstream position with respect to the moving direction, and wherein the image forming apparatus is operable in a control mode in which a bias voltage applied to the first charger is changed with a bias voltage applied to the second charger unchanged.

Abstract: Image forming apparatus in which surface electric potentials of a plurality of surface areas are detected by charging a photoconductor with a different applied bias for each predetermined timing and exposing a plurality of surface areas of the photoconductor by scanning the photoconductor with an optical beam, while changing an exposure intensity of the optical beam for each of the surface areas of the photoconductor. Then, the applied bias necessary for obtaining a predetermined electric potential of a dark section and the exposure intensity of the optical beam necessary for obtaining a predetermined electric potential of a bright section are controlled, on the basis of the surface electric potentials that are detected respectively from the different applied biases and the different exposure intensities. Thereby, the adjustment time can be made shorter than the conventional case.

Abstract: The image forming apparatus includes image forming parts, a developing device and a cleaner to clean at least the intermediate transfer material or the transfer device, wherein at the image forming operation starting time, in each image forming part, after starting the charging, the application of the developing bias is started before the top end of the charging portion of the image bearing member surface reaches a developing area in which the image bearing member and the developer bearing member are set against each other, and from among the areas on the image bearing member in which the charging is not yet performed in each image forming part, in case each area having passed the developing area when the developing bias is applied is brought into contact with the intermediate transfer member, the contact area with each area in the intermediate transfer member is controlled without superposing on the intermediate transfer member.