Abstract: A method of electrophotographically manufacturing a luminescent screen on an interior concave surface of a CRT faceplate panel having a major axis with a first center of curvature and a minor axis with a second center of curvature, the method including the steps of utilizing a charging apparatus for uniformly charging a photoconductive layer disposed on the concave surface of the faceplate panel by providing a corona voltage from a corona generator to at least one corona charger which has an arcuately-shaped charging electrode, the corona charger has a center of curvature substantially concentric with a center of curvature of the concave surface of the panel, a support arm attached to the corona charger is pivotably located at the other center of curvature, the corona charger substantially conforms to, and is spaced from the photoconductive layer on the concave surface, and moving the corona charger across the concave surface.

Abstract: An apparatus and method for providing a charged fluid and for creating an electret from a receptor, such as roll mill polymer film, whereby the electret will have the highest possible static electrical charge within the physical limits of the receptor. The apparatus according to the present invention includes, inter alia, a housing, a plurality of equidistantly spaced electrodes, each electrode having optimum geometry, location and electrification voltage so as to provide a maximum, uniform electric field therebetween, the electrodes collectively forming a charger grid within the housing, and a source of flowing gaseous fluid entering into the housing, the flowing gaseous fluid ionizing at the charger grid, resulting in an optimized corona within the housing. The method according to the present invention induces an optimal corona, defined as a maximum possible electric field having a strength that is near the spark over voltage, in a flowing gaseous fluid by passing the gaseous fluid past the charger grid.

Abstract: A scorotron charging device for charging the surface of a receptor includes a ribbon coronode with a curvilinear field modifying screen surrounding a major portion of the ribbon to level the charge and decrease the possibility of arcing.

Abstract: In an electrophotographic printer, a toner image formed on a photoconductive member is transferred onto a recording medium by charging the recording medium and by making the charged recording medium contact the toner image formed on the photoconductive member. A transfer charger for charging the recording medium is arranged in such a fashion that the transfer charger faces the recording medium at the upstream-side portion, with respect to the feeding direction of the recording medium, of an area where the photoconductive member and the recording medium contact. Therefore, the recording medium is charged at the upstream side of the portion with respect to the lateral center of the portion where the recording medium and the image carrying means contact.

Abstract: A corona discharging device in which an engaging member engages with one of the slits of a control grid is provided on a cover of an end block. When mounting the control grid on the corona discharging device, one end of the control grid is first attached to the device, and the slit formed in the other end of the control grid engages with the engaging member on the cover. Subsequently, the cover is mounted on the end block with its one end serving as a fulcrum surface.

Abstract: An apparatus and method for providing a charged fluid and for creating an electret from a receptor, such as roll mill polymer film, whereby the electret will have the highest possible static electrical charge within the physical limits of the receptor. The apparatus according to the present invention includes, inter alia, a housing, a plurality of equidistantly spaced electrodes, each electrode having optimum geometry, location and electrification voltage so as to provide a maximum, uniform electric field therebetween, the electrodes collectively forming a charger grid within the housing, and a source of flowing gaseous fluid entering into the housing, the flowing gaseous fluid ionizing at the charger grid, resulting in an optimized corona within the housing. The method according to the present invention induces an optimal corona, defined as a maximum possible electric field having a strength that is near the spark over voltage, in a flowing gaseous fluid by passing the gaseous fluid past the charger grid.

Abstract: An electrode assembly for a plasma reactor, such as a plasma etch or plasma-enhanced chemical vapor deposition reactor, comprises an electrode plate having a support frame attached to one surface thereof. The electrode plate is composed of a substantially pure material which is compatible with a particular reaction being performed in the reactor, while the support frame is composed of a material having desirable thermal, electrical, and structural characteristics. The support frame is bonded to the electrode plate using a bonding layer, usually a ductile metallic bonding layer, which provides effective thermal and electrical coupling while permitting a degree of thermal expansion mismatch between the support frame and the electrode plate.

Abstract: A corona charging method and apparatus is disclosed for charging discrete and relatively isolated three-dimensional surfaces of various compositions having a generally exposed surface from which the three dimensional surface extends. The applied charge serves to significantly enhance the wetting and bonding properties of the respective surfaces and is conducted with a relatively concentrated corona emission from discharge electrodes connected to a high voltage source and directed toward the three dimensional surfaces overlying an air gap. The exposed and more accessible surfaces can be treated concomitantly with a field effect diffusion of corona from additional electrodes directed generally toward the exposed surfaces of the composition.

Abstract: A corona wire cleaning device for a corona unit for cleaning corona wires stretched in a shield case, comprising: a driving wire wound on a driving pulley and an idle pulley for reciprocating motion along the length of the corona wire; and a cleaning member slidably mounted in the shield case for traveling motion in association with the reciprocating motion of the driving wire and having a cleaning tool which rubs and cleans the corona wire by the traveling motion thereof in one direction and which comes away from the corona wire by the traveling motion thereof in the other direction, whereby a foreign matter such as dust can be surely removed from the corona wire, thereby accomplishing reliable cleaning of the corona wire.

Abstract: There is disclosed a corona discharger comprising a discharge wire for producing a corona discharge, a voltage source for applying a predetermined voltage to the discharge wire, an electrically conductive back plate being provided on the opposite side of the discharge wire to a member to be electrified, and an electrically conductive side plate being provided close to the member to be electrified. In the corona discharger, an opening for discharging ozone produced by said corona discharge is formed between said side plate and said back plate, and respective electric potentials of the side plate and the back plate are set so that a difference between respective electric potentials of the side plate and the discharge wire becomes lower than a difference between respective electric potentials of the back plate and the discharge wire.

Abstract: An apparatus and method for providing a charged gaseous fluid and for creating an electret from a receptor, such as roll mill polymer film, whereby the electret will have the highest possible static electrical charge within the physical limits of the receptor. The apparatus according to the present invention includes, inter alia, a housing, a plurality of equidistantly spaced electrodes, each electrode having optimum geometry, location and electrification voltage so as to provide a maximum, uniform electric field therebetween, the electrodes collectively forming a charger grid within the housing, and a source of flowing gaseous fluid entering into the housing, the flowing gaseous fluid ionizing at the charger grid, resulting in an optimized corona within the housing.

Abstract: A cleaning device for wire electrode of corona discharger, for example, for use in electrophotographic image forming apparatus, which automatically cleans the wire electrode by relative movement of the wire electrode and cleaning member adapted to contact the wire electrode. Driving of a motor for the relative movement is temporarily stopped at a predetermined time or in response to occurrence of trouble of the relative movement, and started again, whereby the relative movement starts certainly.

Abstract: A universally adaptable corona charger apparatus of simplified construction which is replaceable by an unskilled operator and is inexpensive so that discarding the apparatus when it is no longer useful is cost justified. The corona charger apparatus comprises a conductive corona wire, a generally U-shaped conductive shield, a generally U-shaped non-conductive housing, and a pair of non-conductive end caps. The housing is formed with integral features which retain and accurately space the shield within the housing, locate and properly tension the corona wire, locate and support a grid if required, support electrical terminals for the corona wire and grid, retain and locate the end caps, and enable the assembled apparatus to be accurately located by an unskilled operator. By use of the integral features, the corona charger apparatus is substantially simpified with a concomitant reduction in its cost.

Abstract: A web electricity removing roller which removes static charge appearing on the surface of a web formed of paper, a plastic sheet or the like. The roller has a rotary cylindrical body as the main body thereof for guiding contact with the web. The rotary cylindrical body can be electrically connected to a power source or grounded. A plurality of through bores are formed in the peripheral surface of the cylindrical body and a discharge electrode is disposed within the rotary cylindrical body. The electrically charged particles that are radiated from the discharge electrode by corona discharge form an electrically charged layer on the outer peripheral surface of the rotary cylindrical body which can remove the static charges from the surface of the web in surface contact with the roller.

Abstract: A blow-off gun is provided having a static eliminator having a gas inlet end and a gas outlet end. A removable hollow fiber filter is retained in and extends into the gas inlet end of the static eliminator. The hollow fiber filter communicates with a supply of gas through a handle portion of the gun. Located within the handle portion is a valve and trigger assembly, the valve being provided with a pin hole to supply a constant positive flow of gas, thereby to prevent backflow of ambient air into the gun.

Abstract: A charging device having a coronode that includes a comb-like ruthenium glass electrode silk screened onto a supporting dielectric substrate. The teeth of the comb-like electrode extend to an edge of the dielectric substrate and positionable relative to a screen or slit in several ways in order to form scorotron type devices.

Abstract: A corona discharging device for an electrophotographic copier, laser printer or similar image forming equipment of the type using an electrophotographic procedure. The device has a corona wire, a rear electrode, and a dielectric plate intervening between the corona wire and the rear electrode. A pulse voltage is applied across the corona wire and rear electrode, while a DC bias voltage is applied across the corona wire and a photoconductive element which is located in close proximity to the corona discharging device. A current for charging the photoconductive element is controlled to a predetermined constant value. When the charging current is lowered below a predetermined value or when the DC bias voltage is increased above a predetermined value or decreased below a predetermined value, a high-tension power supply stops feeding a high voltage by deciding that an output is open or short-circuited.

Abstract: An electrocoating system with multistage voltage application includes an electrocoating bath filled with a coating material and having inlet and outlet sides, a feeding arrangement for supporting and moving an object to be immersed and coated in the electrocoating bath so that the object will serve as an electrode, electrode means including a plurality of voltage-application stages arranged successively from the inlet to outlet sides of the electrocoating bath, each of the stages having at least one electrode arranged along a path of travel of an object as moved by the feeding arrangement, power supply means for applying different independently variable voltages through the stages, respectively, and diode means for preventing the electrodes of the stages from being electrocoated with the coating material, the diode means including diodes which are forward-connected respectively between the power supply means and the electrodes of the stages.

Abstract: A new type of corona discharging apparatus. The apparatus revealed is equipped with a pair of thin electrodes which are edge-to-edge parallelly arranged, and bewteen them is an air gap. It is characteristic of this apparatus that the equipped electrodes are allowed to reciprocate along a definite path within a desired distance. By using the apparatus, corona discharge on polymer film can be performed, either in a still or moving state, for a considerable length of time without causing dielectric breakdown. One of the practical applications of this invention is poling of stretched PVDF (polyvinylidene flouride) films to gain high piezolelectric activity with high production yield.

Abstract: A corona discharge device having a modified barrier which improves the discharge properties, is described. The device includes a metal electrode, a low field conductive plane and an ac or dc voltage source for applying a potential to the electrode. The barrier is positioned between the electrode and the plane and, in various embodiments, is in contact with either the electrode or the plane or neither one. The barrier is comprised of any of several materials including a doped glass or ceramic, a porous glass or ceramic, a dispersion of metal with glass or ceramic, a semiconductor, a photoconductor or a fibrous material which functions as a catalyst substrate.

Abstract: A wire cleaning device has a cleaner movable for cleaning a charging wire in a corona discharger, and a motor for moving the cleaner. Whether or not the cleaner is locked somewhat in its stroke of movement is determined by signals from a position detector and a movement failure detector, or signals from an overcurrent detector and a timer. Alternatively, the cleaner which is locked in its moving stroke is forcibly moved by a larger amount of energy than normal, or is vibrated, on the basis of signals from a home position sensor and a failure detector.

Abstract: A paper separation charger for separating papers from a photosensitive member in an electrophotographic copier includes a grid member disposed between a corona wire and the photosensitive member. The grid member is constructed so as to have a higher aperture efficiency at the upstream side of the grid in the paper transport direction than at the downstream side of the grid.

Abstract: A balancing system for electrical A.C. air ionizers having at least one discharge electrode adjacently spaced from a proximity ground and connected to the high side of an A.C. high voltage power source includes (a) a capacitor interposed between each electrode and the high voltage source to maintain a bias on each of the electrodes by blocking the D.C. current component across the circuit capacitance between the discharge electrodes and ground, and (b) a by-pass resistor across the circuit capacitance for providing a path to ground to bleed off excess bias so that equal positive and negative ion densities are generated during corona flow, the by-pass resistor having a resistance value which is determined by the parameters of the system's corona characterisitics (including corona onset voltage and average current flow) that will provide a required equilibrium bias for producing the correct ratios of positive and negative ion currents as will balance the ion densities.

Abstract: A charging device for forming a latent image of high precision includes plural electron beams generated by plural solid state beam sources, which are independently controlled by plural accelerating electrodes by independently variable voltages.

Abstract: An image carrier carries an electrostatic latent image. A charger charges the image carrier to carry the electrostatic latent image. A high-voltage source supplies a high-voltage output to the charger for charging. A temperature detector detects the temperature of the image carrier. A charging controller outputs a control signal for regulating the high-voltage output of the high-voltage source in response to the temperature detection signal from the temperature detector. The control signal has the ability to compensate for changes in the charging of the image carrier by controlling the high-voltage output of the high-voltage source, in accordance with changes in temperature of the image carrier.

Abstract: Apparatus for ionizing air molecules to suppress electrostatic charges in a room or for other purposes includes internal feedback which maintains a desired rate of ion production in the presence of electrode deterioration or other effects which could otherwise alter ion output. Production of air ions of a given polarity results in a ground return flow of electrical charges of opposite polarity from the high voltage generator at a rate corresponding to the rate of air ion output. The ground return current is monitored to produce an electrical feedback signal. A control circuit causes the high voltage generator to apply higher voltage to the electrode when the feedback signal decreases and to apply lower voltage to the electrode when the feedback signal increases. Such self-regulation of each individual electrode in systems having an array of electrodes that are otherwise jointly controlled acts to maintain a desired ratio of positive and negative ions in a room as well as a desired total ion concentration.

Abstract: A scorotron screen for use in a negative corona scorotron charging device comprises a beryllium copper alloy which reduces the problems associated with parking deletions in elecrophotographic process. The screen is fabricated by stamping from beryllium copper sheet metal. Heating the stamped member to a stress relieving temperature induces a tension on the member which enhances flatness.

Abstract: Apparatus and method for effecting a chemical reaction, including a mixer/charger for simultaneously mixing and electrically charging a fluid input to produce a charged fluid output, chemical reaction containment vessel for containing ingredients undergoing a chemical reaction separately from the mixer/charger, and a coupling for fluidically coupling the charged fluid output from the mixer/charger to the containment vessel to influence the chemical reaction. The method includes simultaneously mixing and electrically charging a fluid input to produce an electrically charged fluid output, and delivering the electrically charged fluid to a medium undergoing a chemical reaction to influence the chemical reaction thereof.

Abstract: A fluid jet assisted method for charging a receptor surface to a predetermined voltage includes the steps of generating ions in a chamber, entraining the ions in a rapidly moving fluid stream passing into, through and out of the chamber, depositing the ions on a charge receptor and biasing the back of the charge receptor with a bias equal to and of opposite potential of said predetermined voltage desired on the receptor surface. Both the ion generator and the receptor can be stationary for charging receptor plates or the like, or the receptor could be a moving belt or the like.

Abstract: A method of cleaning film includes:(a) providing a cleaning zone and passing film laterally through that zone,(b) providing streams of gas flowing toward opposite sides of the film as it passes in said zone, and(c) supplying ions of opposite polarity to the air streams and in cyclically reversing polarity relation.

Abstract: A corotron wire cassette including a supply reel seated therein for the acceptance of a wire-shaped electrode is interchangeably provided in a corona-generating means of an electrophotographic printer or copier device. The supply reel in the corotron wire cassette includes a restoring spring. The wire-shaped electrode is conducted via a deflection roller comprising felt rings secured thereon for cleaning the wire-shaped electrode. Connected to the wire-shaped electrode, a coupling clip is provided at the output of the corotron wire cassette, this coupling clip cooperating, in the inserted condition of the corotron wire cassette, with a holding element of a cleaning slide of the corona-generating means. Via an electro-motive means, a control device automatically pulls the wire-shaped electrode out of the cassette in accord with the preset paper width after the cassette is inserted.

Abstract: A ventilated corona charging device for charging a charge receptor includes at least one corona wire to which a high voltage is applied, an electrically conductive shield which partly encloses the corona wire and a blower for directing a stream of air at least into a first region defined between the corona wire and the charge receptor, preferably also into a second region defined between the corona wire and the shield, in order to cause corona discharge which is uniform as well as stable.

Abstract: A device for treating surfaces of objects by means of corona discharge has an electrically insulated discharge electrode in an external tube. The external tube is electrically conductive and grounded. Part of the discharge electrode projects somewhat out of the external tube to define an active, or discharging, region. Between the external tube and the discharge electrode, and air gap exists through which air can be suctioned off during operation.

Abstract: A corona-charging apparatus for charging successive image area segments of a charge-receiving element, which corona-charging apparatus is capable of adjusting the charging rate from one segment to the next while minimizing the transition region between successive image area segments, includes electrode means for creating a corona discharge and a composite grid between the electrode means and a moving charge-receiving element. The composite grid includes a plurality of conductive controlled grid sets with at least one grid wire per set. The grid sets are spaced in the direction of movement of the charge-receiving element, and the voltage on each grid set is adjustable independently of the voltages on the other grid sets. Regulator means are provided for synchronizing the voltage of each grid set with the movement of the charge-receiving element.

Abstract: A corona discharging apparatus is adapted to vibrate a corona discharge wire and/or grid wires by the use of a vibrating element to remove foreign matters deposited on the corona discharging wire and/or grid wires.

Abstract: An apparatus for continuous corona treatment of materials, such as wire. An electrode is helically wound about a tubular glass dielectric, and the electrode is attached to a source of high voltage, high frequency power. In order to facilitate rapid passage of the treated material through the glass tube, blocks with internal pulleys are mounted at either end of the tube.

Abstract: A corona discharge device having a first corona wire and a second corona wire parallel to the first corona wire and in physical contact therewith, such that the forces created by the wires during energization prevent the vibration of the wires, thereby eliminating short circuiting and the need for costly wire-damping devices.

Abstract: A pulse generator operating at a frequency preferably somewhat higher than 100 Hz charges a capacitor through a diode and the trailing edge of the pulse switches-in a discharge circuit to discharge the capacitor through the low-voltage winding of a pulse transformer, the high-voltage winding of which charges, through another diode, the high-voltage insulated conductor of an ionizer that cooperates with a point-bearing electrode that is grounded. The high-voltage electrode discharges through a resistor between pulses and the diode assures that ions of the same polarity will be produced. The ionizer is suited for being located inside a spray gun of an electrostatic coating apparatus for charging the coating material particles with the ions without producing an electric field between the spray gun and the workpiece that would interfere with the coating of hollow places of the workpiece because of the so-called cage effect.

Abstract: A process kit is detachably mounted in the main body of an image forming apparatus and includes a housing in which a photosensitive member, a corona discharger and a developing device are mounted and held as a unit, the housing including an optical opening formed therein upstream of the corona discharger for conducting a homogeneous light to the photosensitive member to eliminate any remaining charge thereon and an opening of exposure for conducting a light of information to the photosensitive member, the exposure opening being located between the corona discharger and the developing device.

Abstract: A corona-charging apparatus includes a conductive control grid, at least one corona-emitting electrode, and means for providing a current supply to the electrode. Current is sinked from the grid through a variable resistance, and means are provided for sensing the voltage produced on the insulating surface to be charged.The electrode power supply is AC, and the grid current sink includes a rectifier circuit. Means, responsive to the sensed voltage adjust the conductivity of the variable resistance in accordance with a predetermined program to thereby maintain the charge on the surface substantially constant.

Abstract: A method of charging or discharging a member including the steps of, opposing to a member to be acted on, a discharging member having a dielectric member, an inducing electrode and a discharging electrode sandwiching the dielectric member so that the discharging electrode faces the member to be acted on, applying an alternating voltage between the inducing electrode and the discharging electrode to produce a surface discharge on a surface of the dielectric member at the discharging electrode side, wherein a charge density of the surface discharge area is changed in the direction of the width of the discharging electrode, and moving the member to be acted on relative to the discharging electrode to be subjected to a low charge density portion and then to a high charge density portion to charge or discharge the member to be acted on by the thus formed surface discharge.

Abstract: An electrical charging apparatus which includes a confronting electrode formed by a metallic plate, a heat-resistant electrically insulative member for covering a surface of the confronting electrode, an exciting electrode in the form of a thin wire fixed to a surface of the heat-resistant electrically insulative member so as to face the confronting electrode through the heat-resistant electrically insulative member, a power source for applying a high voltage AC current between the confronting electrode and the exciting electrode, and a control electrode in the form of a mesh provided to confront the exciting electrode.

Abstract: An electrophotographic process and apparatus for performing the process which employs an electrophotographic photosensitive member of a basic construction in which a photoconductive layer and a transparent insulator layer are sequentially laminated on the surface of a conductive supporter. The process comprises a first step of providing a primary charge uniformly from the surface side of the transparent insulator layer, a second step of performing a secondary corona charging during an imagewise exposure by applying a square wave voltage whose voltage-time integration value of a polarity reverse to the primary charge is larger than that of the same polarity thereas and a third step of forming an electrostatic latent image on the surface of the transparent insulator layer by applying a uniform exposure.

Abstract: An electrophotographic copying machine includes a main housing and an internal frame which can be detachably mounted in position defined in the main housing. The internal frame supports a photosensitive member in the form of an endless belt and a grid electrode. The main housing is provided with a corona discharger comprised of a corona wire and a casing partly surrounding the corona wire to define an opening through which corona ions are emitted. When the internal frame is mounted in position in the main housing, the grid electrode comes to be located opposite to the opening thereby functioning as a part of the corona discharger. Thus, when the internal frame is dismounted, the opening of corona discharger is exposed thereby allowing easy access to the corona wire.

Abstract: An ion generator for the formation of electrostatic images, including two electrodes at opposite faces of a solid dielectric member, using a threshold multiplexing principle for the drive circuit. The apparatus provides a drive signal to each electrode to generate ions in an air region adjacent one of the electrodes, which ions are extracted for electrostatic imaging. Two drive signals each consisting of a sinusoidal alternating potential, out of phase by 180.degree., intermittently induce the production and extraction of ions. Other time-varying potentials of like electrical characteristics may be used, providing a number of operating advantages. The ion generator produces ions only during print periods, and requires reduced power to achieve given ion outputs. The control electrode may be partially encapsulated to limit the discharge region. Drive circuitry such as low source impedance gated oscillators, or other low impedance drivers, reduce capacitive "cross-talk" in a multielectrode device.

Abstract: A cooking oven has an enhanced heating structure for decreasing the cooking time relative to conventional ovens. The enhanced heating structure located on the bottom of the oven has a plurality of spaced apart upward projecting needle electrodes and a heater element located adjacent the needle electrodes. A frame and a flat plate form an enclosure of selected volume for enclosing the needle electrodes and the heater element. The flat plate supports the food for cooking and provides safety and ease of cleaning for the user. An electrical circuit generates a high voltage between the flat plate and the needle electrodes for increasing the rate of heat transfer from the heater element to the flat plate. The temperature of the selected volume enclosed is separately monitored and independently controlled.

Abstract: A device for neutralizing static electric charge on a surface comprising a support means, a plurality of resilient, flexible thin fibers having an electrical resistivity of from about 2.times.10.sup.3 ohm-cm to about 1.times.10.sup.6 ohm-cm., the fibers being supported by the support means in such manner that the fibers are oriented and extend in a uniform direction, in a brush like configuration from the support means so that the distal ends of the fibers may extend toward a surface which has a static charge which one wishes to neutralize. Preferably, the resilient fibers have a resistivity of from about 4.times.10.sup.4 ohm-cm. to about 4.times.10.sup.5 ohm-cm., and are arranged in a linear array of spaced discrete bundles of fibers in a conductive potting composition in the support holder. Preferably the fibers are made of a partially carbonized polyacrylonitrile fiber and the device may be used in an electrostatographic reproducing machine having at least one dicorotron charging device.

Abstract: A corona generating device together with a coronode wire end block assembly is described, wherein the end block includes a spring member adapted for connection to a coronode wire which operates as a circuit breaker at the contact point of the end block thereby terminating the power supply, and preventing a potentially dangerous and destructive arcing situation in the event the wire ruptures. In a preferred embodiment the end block assembly comprises a conductive electrode having at one end a coronode contact and, at the other end a conductive plug adapted for engagement with a power supply contact, with the electrode being positioned in an electrically insulating holder between the coronode contact and the conductive plug. The conductive spring is mounted to the electrically insulating holder on one side of the coronode contact with the other end of the conductive spring being connected to the coronode wire.

Abstract: In a corona charger of the scorotron type, a corona wire is detachably secured to a base frame made of insulating material and a control grid is also detachably secured to a grid frame made of insulating material. The grid frame is secured to the base frame in an easily removable manner. The control grid is resiliently stretched over an opening of the grid frame by means of a coiled spring. The corona wire can be easily cleaned or replaced without removing the control grid from the grid frame, and the control grid can be also simply cleaned or replaced without removing the corona wire from the base frame.

Abstract: A method of charging or discharging a member including the steps of, opposing to a member to be acted on, a discharging member having a dielectric member, an inducing electrode and a discharging electrode sandwiching the dielectric member so that the discharging electrode faces the member to be acted on, applying an alternating voltage between the inducing electrode and the discharging electrode to produce a surface discharge on a surface of the dielectric member at the discharging electrode side, wherein a charge density of the surface discharge area is changed in the direction of the width of the discharging electrode, and moving the member to be acted on relative to the discharging electrode to be subjected to a low charge density portion and then to a high charge density portion to charge or discharge the member to be acted on by the thus formed surface discharge.