Abstract: An image forming apparatus is constructed by: an image bearing member, a charging unit, a developing unit, and a density detecting unit, and densities of developer images as electrostatic latent images formed by changing the charging voltage and the developing voltage are detected by the density detecting unit and, on the basis of detection results, a charging voltage which is applied to the charging unit and a developing voltage which is applied to the developing unit are determined when an image is formed.

Abstract: A charging device includes a charging member for being supplied with a voltage to electrically charge a rotatable member to be charged, the charging member including a magnetic particle layer contactable to the member to be charged, and a carrying member for carrying the magnetic particle layer; wherein the member to be charged starts to rotate after start of application of the voltage and after the start of rotation of the carrying member.

Abstract: An improved electrophotographic printer is provided in which the voltage applied to the charge roller is automatically adjusted to compensate for its changing characteristics over its life span. A high voltage DC power supply includes an output that is connected to the charge roller, and the input side of this high voltage DC power supply is controlled by a microprocessor of the print engine. The print engine controls the output voltage of the high voltage DC power supply by changing the duty cycle of the pulse-width modulated control signal that is supplied to the input of the high voltage DC power supply. A look-up table contains the correct duty cycle for the pulse-width modulated control signal with respect to the number of prints that have been made. The result of the inspection of the look-up table is used by the microprocessor of the print engine to control the correct duty cycle for the pulse-width modulated signal.

Abstract: An electrostatographic recording apparatus and method includes a primary charger establishing a uniform primary electrostatic voltage level on an image recording member. A recorder imagewise modulates the electrostatic charge on the image recording member to form a latent electrostatic image. A development station develops the electrostatic image with toner. A controller controls the primary charger by periodically adjusting a signal to the primary charger in response to a signal related to charger efficiency. The charger efficiency is determined as the ratio of the charger's grid voltage to a voltage level established on the recording member. To calculate changes to the grid, voltage control patches are printed on the member and the densities used to determine changes to setpoint values for the charger.

Abstract: An image forming apparatus has an image forming unit for forming a toner image on a recording material, the image forming unit including an image bearing member for bearing a toner image, and a charging device provided with a magnetic particle layer contactable to the image bearing member to charge the image bearing member; and a determining device for determining an image forming condition of the image forming unit in accordance with a physical quantity relating to a toner amount introduced in the magnetic particle layer or deciding prohibition of the image forming operation of the image forming unit.

Abstract: An image forming apparatus includes a voltage generating section for generating one of an AC voltage and a voltage obtained by superposing an AC voltage on a DC voltage; an image carrier; and a contact charger for receiving the voltage generated by the voltage generating section and giving a surface potential corresponding to the received voltage to the image carrier by contact. Further, it includes a latent image forming section for forming a latent image by scanning the image carrier with a predetermined scanning period, and a control section for controlling the voltage generating section and the latent image forming section. The control section controls the voltage generating section and the latent image forming section so that a period of an AC component of the voltage generated by the voltage generating section is N times or 1/N times as long as the scanning period, where N is a natural number.

Abstract: An image forming apparatus includes an image bearing member; a charging member, contactable to said image bearing member, for being supplied with a voltage to charge said image bearing member; a developing device for forming a toner image by developing with toner an electrostatic image formed on said image bearing member, and also being capable of cleaning said image bearing member to remove residual toner; and a transferring device for transferring the toner image onto a transfer material. When the apparatus stops during an image forming operation as during a jam, the voltage applied to said charging member is a superimposed voltage of an AC voltage and DC voltage and is a DC voltage without the AC voltage thereafter between resumption after jamming and the start of image formation.

Abstract: A method for cleaning an image-forming apparatus. Toner is charged to the first polarity prior to transferring the toner image to the print medium and accidentally inverted from the first polarity to a second polarity opposite to the first polarity during the transfer of the toner image to the print medium. When performing a cleaning operation, a first voltage of a first polarity is applied to at least one of a charging roller and a cleaning roller in contact with a surface of a photoconductor. The surface of the photoconductor is charged to a second voltage. The second voltage has a smaller value than the first voltage and is of the same polarity as the first voltage. Therefore, the toner of the second polarity sandwiched between the charged surface of the photoconductor and the at least one of the charging roller and cleaning roller is inverted in polarity, i.e., from the second polarity to the first polarity by triboelectric charging.

Abstract: A charge roller has a steel shaft and conductive outer cylindrical body which is formed by curing with heat a blend comprised of epichlorohydrin rubber, mineral-oil-free zinc oxide dispersion, stearic acid as a lubricant, accelerators and a sulfur donor. The roller has a long useful life and does not express oil while inactive.

Abstract: A brush type charger capable of reducing noise which occurs on superposing AC voltage on DC voltage and of restraining image defects such as moire images and density unevenness from occurring will be supplied.In a brush type charger, having a shaft 1A for brush made of a conductive member, and a brush-shaped charging member 1B which is radially provided toward the outside around the shaft 1A for brush, and which is made of a conductive member entirely formed into a roller shape, configured such that the outer circumference of the brush-shaped charging member 1B is brought into contact with a photoreceptor 3 and predetermined DC voltage having AC voltage superimposed thereon is applied to the brush-shaped charging member 1B to thereby charge the photoreceptor 3, the brush-shaped charging member 1B is provided in a helical fashion around the shaft 1A for brush.

Abstract: An image forming apparatus includes an image bearing member for bearing an image. A charging device is supplied with a voltage. The charging device includes a magnetic brush contactable to the image bearing member to electrically charge the image bearing member. A developing device develops, at a developing position, an electrostatic image formed on the image bearing member using a charging operation of the charging device, with toner having the same polarity as a charging polarity of the charging device, into a toner image. The developing device is capable of removing residual toner from the image bearing member. The developing device stops its developing operation if an area of the image bearing member, which has been charged by the charging device when the charging device is being supplied with an oscillating voltage in the form of superimposed AC and DC voltages, is still at the developing position.

Abstract: An image forming apparatus has an image bearing member, an image forming unit adapted to form a toner image on the image bearing member and having a first charge member for charging the image bearing member with the same polarity as normal polarity on toner, an intermediate transfer member, a voltage apply means for applying voltage to the intermediate transfer member to electrostatically transfer the toner image formed on the image bearing member by the image forming unit onto the intermediate transfer member at a first transfer station, a second charge member for charging residual toner remaining on the intermediate transfer member with polarity opposite to the normal polarity of the toner on the image bearing member, after the toner image on the intermediate transfer member is electrostatically transferred onto a transfer material at a second transfer station, and a controller for variably controlling voltage applied to the first charge member, and the voltage application generates an electric field for tr

Abstract: An image forming apparatus of the present invention includes at least an image carrier and a contact type charging device. The image forming apparatus further includes a control control device that controls the contact type charging device so as to apply DC voltage having the same polarity as the charging polarity of the image carrier to the image carrier at the same time that or before rotation of the image carrier begins and successively applies a voltage in which AC voltage is superimposed on the DC voltage at the same time that or after the DC voltage is applied and at the latest after the rotation of the image carrier begins. Therefore, according to the present invention, electrostatic memory in the image carrier is prevented, so that the occurrence of black stripe or the like corresponding to a contact point of the contact type charging device is prevented, thereby enabling formation of high quality images.

Abstract: The present invention provides a contact type charging device for applying a lower frequency AC voltage in combination with a DC voltage to an electric charger so as to suppress generation of noise in the electric charger as well as eliminate a Moire image in a half tone image when the DC voltage is overlapped with the lower frequency AC voltage, thus enabling to improve a charge uniformity. The charging device includes: an electric charger 1 that is in contact with an electrostatic latent image carrier 100 and applies a predetermined voltage to the electrostatic latent image carrier 100 for charging it; and a power source consisting of a DC power source 13 and an AC power source 15 for applying to the electric charger 1 a DC voltage in combination with an AC voltage. The AC power source 15 has a frequency of a predetermined value corresponding to a latent image to be formed on the electrostatic latent image carrier 100.

Abstract: A lamp power supply circuit for an image forming device, which is not provided with a full-wave rectifier and any additional noise reducing circuit but is capable of effectively suppressing inrush current not to produce noise that may cause erroneous operation of the image forming device and affect any external appliance. A lamp lighting control system for use in an image forming device, which can realize soft-starting of an exposure lamp or a fixing heater-lamp by gradually increasing a conducting angle .beta..sub.i (i=0, 1 . . . ) for applying a voltage to a lamp through phase control of an AC power-supply voltage V.sub.AC for an initial period of energizing the exposure lamp or the fixing heater-lamp. Wherein, the conducting angle is gradually increased per even-number unit of cycles of AC power-supply voltage V.sub.AC on the condition that even numbers of cycles in the same unit have the same conducting angle, e.g., .beta..sub.0 =.beta..sub.1 <.beta..sub.2 =.beta..sub.3 <.beta..sub.4 =.beta..sub.

Abstract: Disclosed is a method for cleaning the contact charger of an electrophotographic apparatus including a photosensitive (photoconductive) drum, developing means, transfer means and main motor, which comprises the steps of applying a charging voltage of a specified level to the contact charger to make the surface of the photosensitive drum keep a surface potential of a given level during rotation of the main motor, cutting off the charging voltage applied to the contact charger and developing voltage applied to the developing means after a specified time so as to transfer the toner of opposite polarity attached to the contact charger to the photosensitive drum, and applying a negative transfer voltage to the transfer means so as to transfer the toner of opposite polarity transferred to the photosensitive drum to a sheet of paper.

Abstract: A digital copying machine develops an electrostatic latent image formed on a photosensitive drum with toner, and transfers the developed image onto a sheet. In forming images on the photosensitive drum successively, three types of test patterns are formed in order in intro-image areas between image forming areas, and AIDC is made. The first test pattern is a low-density pattern, the second test pattern is an intermediate-density pattern, and the third test pattern is a high-density pattern.

Abstract: An image quality control apparatus controls quality of xerographic images formed by a xerographic imaging system onto a recording medium when at least one sensor which is operative to provide signals to the xerographic imaging system for quality control malfunctions. The image quality control apparatus includes a controller device in communication with the xerographic imaging system. The controller includes a data collection device, a determining device and an input generating device. The data collection device collects and processes sensor data received from the at least one sensor while the at least one sensor is operative. The determining device determines whether the at least one sensor malfunctions.

Abstract: This invention relates to a image forming apparatus comprising an image carrier, charging means, image exposing measuring means, surface correction toner image forming means for forming a toner image extending in parallel to a direction of a rotation axis of the image carrier at a non-image area on the surface of the image carrier and a controller for changing a formation condition of the surface correction toner image formed parallel to the direction of the rotation axis of the image carrier at the non-image area on the surface of the image carrier by the surface correction toner image forming means, according to the surface roughness or the physical property value reflecting the surface roughness of the image carrier measured by the measuring means.

Abstract: A charging apparatus includes a rotatable charging roller contactable to a member to be charged to electrically charge the member to be charged. The eharging roller includes a foam member and is supplied with a voltage including an oscillating component. A control means is provided for constant-current-control of the oscillating component. When the constant-current-control is carried out, a response time of the constant-current-control is longer than time required for a width to be charged to pass through a discharge area between the charging roller and the member to be charged.

Abstract: An apparatus for monitoring and controlling electrical parameter of an imaging surface, the monitoring controlling apparatus including a patch generator for recording a first control patch at a first voltage level and a second control patch at a second voltage level on the imaging surface; electrostatic voltmeter for measuring voltage potentials associated with the first control patch and second control patch. A processor, in communication with the patch generator, calculates the electrical parameters of the imaging surface from the measured voltage potentials from the first and second control patches. The processor determines a deviation between the calculated electrical parameters values and setup values. Then, the processor produces and sends a feedback error signal to the patch generator if the deviation exceed a threshold level. The patch generator records a third control patch at a third voltage level on the imaging surface upon reception of the error signal. The ESV senses the third control patch.

Abstract: The present invention provides a control method for controlling of output of a constant voltage power source so that a current value detected by a current detect means becomes to a predetermined current value, by applying voltage from the constant voltage power source to a voltage applied member and by detecting current flowing the voltage applied member by the current detect means and by changing the voltage applied to the voltage applied member every certain voltage width, wherein the voltage width can be varied with a difference between the predetermined current value and the current value detected by the current detect means.

Abstract: An image forming apparatus includes a photosensitive body, a charging member for charging the photosensitive body, voltage applicator for applying a voltage including an AC component to the charging member, exposing device for image exposing on the photosensitive body charged by the charging member to form an electrostatic image, and developer for developing the electrostatic image, wherein the image forming apparatus can select from a first mode having low tone reproductivity and a second mode having tone reproductivity higher than that of the first mode, and wherein, when the second mode is selected, the voltage applicator applies a voltage having a frequency of the AC component higher than that when the first mode is selected.

Abstract: The present invention aims to improve image quality in an image forming apparatus in which plural color toner images are formed on a photosensitive member and the toner images are collectively transferred onto a transfer material, and provides such an image forming apparatus that includes a first charge member for charging the photosensitive member, a digital optical system for exposing image information on the photosensitive member, a first developing device for inversion-developing a first latent image formed on the photosensitive member with first toner, a second charge member for charging the photosensitive member developed by the first developing member, a second developing member for developing a second latent image formed on the photosensitive member by exposing second image information onto the charged photosensitive member, with second toner, and a transfer means for collectively transferring first and second toner images formed on the photosensitive member onto a transfer material, and wherein an ex

Abstract: A charger for charging the surface of a photoconductive drum by a contact charging method in an electrophotographic image forming apparatus includes: a charge roller for charging an unexposed surface of the photoconductive drum to a prescribed potential by contact with the surface of the photoconductive drum; a power supply connected to the charge roller, for supplying a variable DC charge voltage to the charge roller; a potential sensor installed around the photoconductive drum, for detecting a charge potential value of the unexposed surface of the photoconductive drum; and a controller for comparing the charge potential value detected by the potential sensor with a specified value, and changing the charge voltage generated by the power supply upon detecting any difference therebetween, so as to maintain the charge potential of the photoconductive drum at a constant value.

Abstract: An electrophotographic apparatus is provided with suppressed or eliminated electrostatic fatigue and physical wearing-off of a photoconductive element and drive system layout, and is further provided with resultant reduced running cost which is realized by minimum rotation of a photoconductive element and minimum applying time of an impressive charger for each image forming procedure. The electrophotographic apparatus is provided with optional feeders in addition to a main feeder, and a detecting device is provided at a position capable of detecting a tip end position of a recording sheet at an upper stream of a transfer process, from any of the main sheet feeder or the optional sheet feeders, in which a photoconductive element motor or charge applying process is started in accordance with an output of the recording sheet detecting device.

Abstract: The present invention, for example, forms a test pattern image on the surface of a photosensitive member at predetermined periodicity and detects the density of said test pattern image. If the detected density value of the test pattern image is other than said target value, the charging voltage is preferentially adjusted to maintain a stable toner density. When the adjusted charging voltage attains either an upper limit or a lower limit, the toner density is adjusted.

Abstract: An electrophotographic printing apparatus has two charging bodies that are held at different potentials. The first charging body makes contact with the surface of a photosensitive drum; the second charging body makes contact with the first charging body. Toner particles that have acquired an electrostatic charge opposite to their normal charge are attracted from the drum surface to the first charging body. These toner particles are then attracted from the first charging body to the second charging body, whereby the first charging body is kept clean and able to charge the surface of the photosensitive drum to a uniform potential.

Abstract: An image forming apparatus wherein a developer remaining on a photosensitive member after an image transfer process is removed by developing means, the apparatus includes an electrophotographic photosensitive member; a contact charging means including an electrode contacted to the photosensitive member to electrically charge the photosensitive member, the contact charging means being supplied with a bias voltage form a charging bias voltage source; exposure means for exposing the photosensitive member to form an electrostatic latent image thereon after the photosensitive member is electrically charged by the charging means; developing means for supplying the developer from a developer carrying member to a latent image portion of the photosensitive member to develop the photosensitive member and simultaneously removing the developer remaining on the photosensitive member after the transfer process and conveyed to a downstream of the contact charging means on the photosensitive member, to the developer carrying

Abstract: A method of cleaning is used to remove residual toner in an electrophotographic printer. After a printing operation, some amount of normally-charged toner and reversely-charged toner is left on the photoconductive drum and rollers such as charging rollers, transfer roller, and cleaning roller in contact with the photoconductive drum. A potential difference is applied between two members, for example, the cleaning roller and the photoconductive drum in electrical contact with each other so as to cause the residual toner to migrate from one member to the other. The potential differences are applied at specific timings so that the residual toner migrates properly onto the rotating photoconductive drum and is carried to the developing section for reuse.

Abstract: The surface of a photosensitive body is evenly charged by a charging member, and then the charged surface is exposed to light by an exposure device in order to produce an electrostatic latent image. A toner is caused to adhere to the latent image by a developing roller and then is transferred to paper. The temperature of the charging member is detected by a temperature detecting device and, in accordance with the detected temperature, a voltage to be applied to the charging member is corrected by a voltage correcting device. An aging change of the photosensitive body is detected by an aging change detecting device and, in accordance with the amount of the aging change, a correction rule for an applied voltage corrected by the voltage correcting device is changed by a correction rule changing device. A potential of the surface of the charged photosensitive body or a developing bias of the developing roller in an image forming process is corrected by a potential correcting device.

Abstract: An electrophotographic apparatus includes an electrophotographic photosensitive member, a charging device, an image exposure device, a developing device, a transfer device, and a control device. The control device stops rotation of the electrophotographic photosensitive member after a region of the electrophotographic photosensitive member, which region opposes the transfer device at the time when operation of the transfer device is stopped while the rotation of the electrophotographic photosensitive member is not stopped, passes, by at least one revolution, a position opposing the charging device which is running. The electrophotographic apparatus requires no idle rotation, makes high speed processing possible, suppresses negative and positive ghosting, and suppresses variations in electric characteristics and in image densities between first and second copying operations, thereby enabling images of high quality to be prepared quickly and simply.

Abstract: A test pattern image is formed on a photosensitive drum, and the density of the test pattern image is detected by a sensor. The grid voltage Vg of an electrifying charger and the toner concentration T/C in a developer are adjusted according to the detection result so that a target image density can be obtained. Every time a specified number of copies are made in a multiple copying operation, the adjusting target value of the toner concentration T/C is lowered by one step, and the adjusting target value of the grid voltage Vg is heightened by one step.

Abstract: An image forming apparatus includes an image bearing member; a charging member, contactable to the image bearing member, for being supplied with a voltage to electrically charge the image bearing member, the charging member having a resistance which is larger when it is supplied with a voltage of 50V than when it is supplied with a voltage of 500V; developing device for developing with toner an electrostatic image formed on the image bearing member using charging operation of the charging member, the developing means being capable of removing the toner from the image bearing member; wherein the voltage is an oscillating voltage, and a ratio T.sub.up of time period when a voltage level thereof is in a side of a charging polarity of the charging member beyond an average voltage in one period of the oscillating voltage to a length of time of one period of the oscillating voltage, and a ratio T.sub.

Abstract: An image forming apparatus including a photosensitive member, a first developer for developing an electrostatic latent image on the photosensitive member, a charger adapted to charge the photosensitive member bearing a first developed image formed by the first developer and having a discharge electrode member and a shield member surrounding the discharge electrode member, an exposure device for image-exposing the photosensitive member charged by the charger, a second developer for developing an electrostatic latent image formed by exposure of the exposure device, and a voltage apply device for applying voltage having the same polarity as that of the first developed image to the shield member.

Abstract: The development of the edges of discharged areas on a photoconductor drum in an electrophotographic printing system is controlled by the ratio of the DC component of the developer bias to the magnitude of the difference between the DC component of the developer bias and the DC component of the bias supplied to the photoconductor charge roller. A development system using a developer, a photoconductor charge roller, a high voltage power supply, an optical density sensor, and a controller for controlling the high voltage power supply optimizes the electrophotographic edge development. The optical density sensor is used in a calibration process to determine the value of the DC component of the developer bias necessary to ensure the optical density of developed areas will meet the minimum specified optical density.

Abstract: A setup method for a corona charger device used in an electrophotographic recording apparatus. The setup method includes operating the corona charger device in a calibration mode so that charge of a first polarity is output by the device and deposited upon a photoconductive recording member. The level of charge deposited upon the member is sensed and a position of the charger device relative to the member is adjusted so that the level of charge deposited upon the member is at a target level. The charge of the first polarity output for setup is opposite to that of charge output during the production run.

Abstract: An apparatus and method that insures an even distribution of liquid in an aquatron charging device across the entire length of the device. This enables uniform charging across the width of the photoreceptor. The present invention fills and pressurizes a porous tube with a liquid. The liquid evenly exudes from the pores along the entire length of the porous tube. A hydrophilic liquid retentive foam which contacts the photoreceptor surface is wrapped snugly around the tube. The conductivity and overall rate of dispensation of liquid is controlled by the pressure differential across the porous tube.

Abstract: The present invention provides an image forming apparatus that suffers less toner particles scattering and a narrower variation in image density. In this image forming apparatus, a decrease of a contrast potential difference can be compensated by means of a developing bias voltage generator circuit and a grid bias voltage generator circuit, so that the image density can be kept constant. The apparatus includes a developing mechanism in which the respective average particle diameters of carrier members and toner particles, toner concentration, and the diameter and peripheral speed of a developing roller are optimized. Although the diameter of the developing roller is small, therefore, a high image density can be secured, and the value of toner particles scattering can be lowered.

Abstract: When an electrophotographic printer is manufactured, the initial electrical resistance of its transfer roller is measured and a corresponding value is stored in a memory device in the printer. During operation, the printer's control program estimates the resistance of the transfer roller from the stored value, taking aging into account, then measures the actual resistance of the transfer roller, and infers ambient conditions from the difference between the estimated and actual resistance values. The electrophotographic printer is controlled according to the inferred ambient conditions.

Abstract: In an image forming method in which an image is formed through the charging, exposing, developing, transferring, and charge eliminating steps using an amorphous silicon photoreceptor having an amorphous silicon photosensitive layer, an image forming method according to the present invention is so adapted that letting t1 be a time period from the charging step to the developing step and t2 be a time period from the charge eliminating step to the charging step, the value of t2/t1 is not less than one.

Abstract: In a method of adjusting image forming conditions according to the present invention, it is judged whether or not a humidity detected by a humidity sensor is not less than a predetermined first humidity H.sub.1 (step W6). As a result, when it is judged that the humidity is not less than the first humidity H.sub.1, a main charger table is accessed using the detected absolute humidity as an address, and corresponding additional data G is read out (step W7). The additional data G read out, together with additional data E and main charger driving time adjustment data F, is added to main charger reference data K.sub.2, so that main charger voltage data C.sub.2 is produced (step W8). On the other hand, when the detected humidity is less than the first humidity H.sub.1, a voltage to be applied to a main charger is not adjusted depending on the humidity.

Abstract: In order to achieve such effects that memories such as image memory due to untransferred residual toner can be sufficiently prevented, and good images can be obtained by suppressing base fogging and reduction of entire image density for a long term, an oscillating voltage composed of a DC ingredient and an oscillating ingredient is applied to a charging device for charging a photosensitive member, while the charging device is in a position facing an image forming region of the photosensitive member. While the charging device is in a position facing an image non-forming region of the photosensitive member, only a DC voltage is applied to the charging device for at least a predetermined time.

Abstract: A charging method in which the surface of an image bearing device is charged in two steps in contact with the surface of the image bearing device before a latent image is formed on the surface of the image bearing device, the contact charging method includes two steps. First, the surface of the image bearing device is charged with a contact charging device which applies a voltage consisting of an AC component and a DC component superposed on the AC component. Second, the surface of the image bearing device is charged by a contact charging device applied with such a DC voltage as to discharge at least part of a pattern of charge potential variation of which the pitch corresponds to the frequency pitch of the AC component, which is caused in the primary charging operation.

Abstract: The image forming apparatus of the invention controls the toner density by any one of the following configurations: by correcting the toner density of the developer in association with the agitation total; by controlling a process parameter so that the density of a toner patch formed on the photoreceptor corresponds to a prescribed density value and determining that developing performance of the developer is improved and canceling the toner density correction when the process parameter reaches the prescribed value; by changing the toner density reference value when the variation as to the charger output is equal to or greater than a first predetermined value and maintaining the changed toner density reference value until the variation of the charger output again becomes equal to or greater than the first predetermined value; or by prohibiting toner supply for a constant duration to prevent excessive toner supply if time from the end of the last operation of the developing unit to the start of a next operation

Abstract: An image forming apparatus includes image bearing member for bearing a toner image; charging member contactable to the image bearing member to electrically charge the image bearing member; wherein .delta.V=.vertline.Vdc-Vs.vertline. is different between a first area of the image bearing member which is going to be image area and second area of the image bearing member which is going to be non-image area, where Vdc is a DC component of a voltage applied to the charging member, and Vs is is a potential of the image bearing member charged by the charging member.

Abstract: An electrostatic recording apparatus includes a background potential detector (12a, 12b, 13a and 13b) for detecting the potential (VMc) of a background region adjacent to a normal development region (having VHc) and the potential (VMd) of a background region adjacent to a reversal development region (having VLd), and a controller (25) for controlling a charge voltage, exposure intensity, and/or developing bias voltage according to the output of the background potential detector to eliminate a fogging phenomenon.

Abstract: In an image forming apparatus having an auto power-off function, the durability of a roller of a heat fusing member or the like is improved. Before a lapse of a specified time .DELTA.t from a time T at which an auto power-off timer stops time counting, a fusing roller is driven for the time .DELTA.t. By this operation, the fusing roller is consistently driven within the set time of the auto power-off timer, thereby reducing a continuous stress in a nip portion of the fusing roller.

Abstract: Developer material remaining on an image bearing member after transfer are collected by a developer. A cleaning member is arranged between a charger and an exposure in contact with the image bearing member, for collecting the residual developer material. A bias controller controls biases to be applied to a cleaner, a charger, and a developer. During an image forming process, the biases are so determined that the residual toner on the image bearing member is collected by the cleaner. While the image forming process is not performed, the biases are so determined that the collected toner is removed from the cleaner to the image bearing member and then collected by the developer.

Abstract: CPU is designed to create toner patches on the surface of the photoreceptor drum and pick up the detected data of the density of the toner patches by a photosensor. CPU calculates a correcting value .DELTA.Vg of the charger output in accordance with the picked up detected data, and compared the corrected charger output Vg with (Vgs+.alpha.) and (Vgs-.alpha.). If the corrections in the same direction are repeated in a row, k.beta. (where 0<k<1) is added to or subtracted from the toner density reference value. When the direction of the correction for the toner concentration reference value to be made is opposite that of the previous one, the absolute value of the correcting value for the current correction is set to be the absolute value of the previous one.