Abstract: A corona generating device for producing uniform charge along the length of the generating device is described which comprises a plurality of separate parallel coronode wires supported between insulating end block assemblies with the coronode wires being closely spaced relative to the adjacent wire such that when energized, each wire is placed within the electrostatic fringe field of the adjacent wire. In a preferred embodiment the device comprises a pair of parallel coronode wires formed from a single U-shaped wire with a closed end portion wrapped around an arcuate insulating end post in a first end block assembly, and an arcuate insulating end post in the second end block assembly around which the ends of the coronode wire may be wrapped, and insulating block adapters at both ends of the device having wire positioning slits therein, the end post being larger in diameter than the width of said slits in said end block adapters whereby the pair of wires is urged against opposite sides of the slit.

Abstract: A method and apparatus for producing a uniform elongate corona is provided. The apparatus includes at least one stationary corona electrode coupled to a supply of corona voltage. A moving ground electrode having a series of equally-spaced grounding points is coupled to a bias circuit that returns to ground. The moving ground electrode may be arranged to form a helix on a motor-driven insulating rod, with the longitudinal axis of the rod parallel to the stationary elongate corona electrode at a predetermined distance therefrom. The supply of corona power provides a high negative D.C. voltage or a series of high frequency negative high voltage pulses. The preferred bias circuits include one of a self-bias provided by a high resistance; a high frequency pulsating D.C. power supply circuit; or a fixed value negative D.C. power supply circuit.

Abstract: An electrophotographic process 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 in one preferred embodiment 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 an a.c. voltage in which the firing angle of a negative half wave is controlled in phase to be within a phase angle corresponding to a lower voltage than the firing angle so that the positive discharge period may be longer than the negative one during one period, and a third step of forming an electrostatic latent image on the transparent insulator layer by applying a uniform exposure.

Abstract: An electrode shield device for use in conjunction with a needle electrode preferably embodied in an oven. The shield device includes a perforated plate and mechanical means supporting the plate for causing relative movement between the plate and the needle electrode. In operation, the mechanical means locating the plate in a spaced relationship to cover the needle electrode for preventing physical contact with the needles when the electrode is electrically inactive and the mechanical means locating the plate in an engaging relationship to expose the needles for permitting the needles to establish current contact with, for example, high potential food.

Abstract: In an electrophotographic reproduction apparatus and method, a moving photoconductor is charged by a primary corona charger that includes a corona wire. Nonuniformities in the charge pattern produced on the photoconductor by this primary line charger are reduced by subjecting the photoconductor to a second corona charger having point charging electrodes.

Abstract: Apparatus to reduce static electricity in a work zone comprises:(a) a first electrical conductor having first tips spaced therealong in a first row to dispense positive ions in response to first voltage application to the first conductor,(b) a second electrical conductor having second tips spaced therealong in a second row to dispense negative ions in response to second voltage application to the second conductor, said first and second voltages being different, and(c) a body mounting said conductors at locations and separations from one another characterized in that static electricity at or proximate the work to be treated is effectively reduced to non-objectionable levels when said differential voltages are applied to the conductors,(d) the first and second rows being parallel.

Abstract: An electrostatic reproducing apparatus in which a passage of ions generated from an ion generator is modulated by an ion modulating electrode which modulates corresponding to image signals that are to be reproduced. An ion flow condensing electrode comprising an insulating plate and a conductive plate coated on one surface of said insulating plate is disposed between said ion generator and said ion modulating electrode. Said electrostatic reproducing apparatus comprises an electrode for deflecting the flow path of ion flow, said electrode for deflecting being disposed on the side opposite to said ion generator of said ion modulating electrode, and being applied with a predetermined potential with respect to said ion modulating electrode.

Abstract: Excessive heat-generating current levels produced in semiconductive materials by electrostatically assisted coating apparatus employed to, for example, improve the uniformity of a coating applied to such materials are avoided by passing an auxiliary current through said semiconductive materials in the same region and in a direction opposite to that of the current produced by said electrostatically assisted coating apparatus such that the difference between the said current produced by said electrostatically assisted coating apparatus and the said auxiliary current is less than or equal to a predetermined value.

Abstract: A line spacer for a pair of insulated conductors each having conductive points projecting laterally beyond the insulation thereof in a common direction at sites spaced therealong, comprising a block of insulating material having a pair of laterally spaced grooves extending therealong near opposite edges thereof and opening to a first surface of the block, the grooves being deeper than the sum of the conductor diameter added to the point projection, and means severally accessible from the opposite edges of the block for compressively retaining the conductors against motion in said grooves.

Abstract: Control apparatus for a corona discharge device to be utilized in a xerographic reproduction machine. The control is characterized by utilizing the shield or coronode voltage to derive signals which can be used for maintaining the photoconductive surface of the machine at a predetermined voltage level. The voltage level on the shield or coronode is measured twice, once with the surface in its conducting state and with the surface in its non-conducting state. The difference between the two voltages is compared to a reference voltage to generate an output signal for controlling the voltage applied to either the shield or coronode depending upon which is being used.

Abstract: In a xerographic reproduction machine there is provided apparatus for partially neutralizing charge on the backside of a copy sheet electrostatically adhered to a photoconductive surface. Included in the apparatus is a conductive wire having a relatively thick insulative outer coating which is sufficiently thick that with an a.c. voltage applied to the conductive wire there is substantially no net d.c. current flow from the wire in the absence of an external electrostatic field. Such a construction of wire and outer coating is known as a dicorotron electrode. A net positive current flows from the wire to the back of the paper when an external electrostatic field is established between the conductive shield and the copy sheet by moving said copy sheet with a positive voltage on its backside past the conductive wire.

Abstract: A charger for electrophotographic surfaces wherein a pair of corona wires (1 and 2) are spaced apart parallel to but spaced from the surface (4) which is to be charged and have the corona-producing voltage applied between them, the wires preferably being enclosed in a shield (5) and there being a control electrode (3) behind the surface being charged, the electron field preferably being applied intermittently at a selected frequency by out-of-phase supply means comprising transformers (20, 21), transistors (22, 23) and cross coupling condensors (24, 25), the control electrode being earthed or having a potential applied thereto by means such as a battery (18 or 32).

Abstract: An ion modulating electrode to form an electrostatic image on the image recording member by modulating the ion flow includes a multi-layer structure consisting of a first conductive layer and a first dielectric layer, a second conductive layer, and a second dielectric layer and a third conductive layer, stacked together in that order to form a multi-layer structure, through-apertures formed in this multi-layer structure, and a dielectric or semiconductive thin film coated on the first conductive layer or third conductive layer. A high-frequency voltage is applied between the first conductive layer and the second conductive layer to produce ions in these apertures. A voltage is applied to the third conductive layer for enhancing the passage through the apertures of ions generated in these apertures by high frequency voltage. The thin film covers a part of the inside of the apertures.

Abstract: A corona device comprising a multiplicity of electrode pins embedded in a body of insulating material has each pin projecting from two sides of the insulating body and has this body disposed between two conductive elements, or electrodes, which are connectable to the opposite poles of a voltage source. The ends of each pin are in the electric field between the electrodes at locations between which a high potential difference is present, so that a corona discharge may develop between each end of a pin and the related electrode. The corona device may also comprise provisions for inhibiting deterioration of the pin ends subject to positive corona discharge, and/or for counteracting the positive potential so that no positive corona discharge will occur.

Abstract: A brush-like device having an array of conductive bristles is able to establish a relatively uniform dipole type electrostatic charge level on, for example, a moving web of charge-retaining material by passing said web through the relatively strong electrostatic field established by such a device when it is electrically connected to a relatively low potential DC source having the proper magnitude and polarity.

Abstract: Apparatus and method for efficiently transferring energy through a medium between a source and a target which in one form includes a rigid frame supporting a plurality of electrically conductive probe strips having probe tips or points spaced therealong and a plurality of connected grid wires or rods in spaced relation to the probe tips or points and electrically insulated therefrom. The grid wires are arranged in at least a pair configuration with respect to each of the probe strips. The probe points are disposed in facing relation toward the target and each grid wire pair is equally disposed in relation to the axis of the probe strip points that it serves. A high voltage low amperage direct current source is connected to the probe strips. In another form the apparatus includes a single probe tip or point in combination with a pair of electrically connected grid wires.

Abstract: A method and an apparatus for charging a dielectric layer electrostatically to a predetermined potential. An AC electrode is arranged at a distance from the dielectric layer and connected to one output of an AC voltage generator. The AC voltage generator has the other output connected to an output of a DC voltage generator. Between the AC electrode and the dielectric layer there is a DC electrode which is connected to the other output of the AC voltage generator. The dielectric layer rests on a counter-electrode which is connected to the other output of the DC voltage generator and is at ground potential. Each of the electrodes can comprise one or a plurality of mutually insulated single electrodes.

Abstract: An electronic copying apparatus is provided of the type in which an electrostatic latent image is formed on a record medium and developed with a toner powder to provide a visual image which is then transferred onto a transfer paper. A neutralizer has a conductive shield plate which includes a side plate which is located at an advanced position as viewed in the direction of movement of the record medium and which is spaced a given distance from the surface of the record medium, maintaining an electric field formed therebetween below 2 kV/cm. A conductive electrode plate is disposed close to an image carrier or a record medium which moves while retaining the visual toner powder image, and a voltage of the same polarity as that of the toner powder is applied to the conductive electrode plate.

Abstract: Electrostatic charge images of identical shape but opposite sign are generated on both sides of a transparent, highly insulating foil. Subsequently, pigment is deposited on both sides of the foil by means of oppositely charged developers. The optical density of an electrophotographic image on a transparent insulating foil is increased, as compared to densities achieved in the past, for a given surface charge density by establishing a charge exchange between one side of the foil and an electrode. On the other side of the foil a charge image is generated and the foil. The electrode are separated from each other prior to development.

Abstract: A corona device suitable for use in electrophotographic apparatus to provide a uniform charge on photoconductive material comprises as the ion-generating means a multiplicity of electrode pins, all of the same diameter, which are provided at the same mutual spacing from one another in a body of insulating material from which all the pins project to the same extent, with the pins limited to a diameter between 10 and 100 microns, a mutual spacing of between 0.3 and 2.5 mm, a projecting length of between 0.7 and 3 mm, a length to diameter ratio of between 10 and 300 and a spacing distance to diameter ratio of between 4 and 250. The electrode pins are formed from lengths of a suitable conductive wire which are laid at the required mutual spacing and soldered to and between conductive strips to form an electrically conductive unit that is embedded in a cast body of the insulating material with free ends of the wire lengths projecting to the required extent.

Abstract: A charging device for charging paper and other flexible material comprising a cylindrical cavity (16) in a housing (10) having an inlet and an outlet (typically a single slit) (12)) into which and from which the flexible medium (14) can pass. Centrally along the axis of the cavity is a charging conductor (28) and the conductive interior of the cavity (20) and the conductor (28) are connected to opposite sides of a source of potential (38). A perforated cylindrical guide (30) may be located within the cavity so as to define a narrow annular gap around which the flexible medium can pass. Three rollers (32,34,36) forming entrance and exit nips for the flexible medium (14) may be located at the entrance/exit slit.

Abstract: A supersonic jet ionizer (10) comprises dielectric structure defining a chamber (30) for receiving pressurized gas and a convergent-divergent nozzle (31) for causing the gas to issue from the chamber (30) in a jet at supersonic velocity. A high-voltage electrode tip (51) and a grounded metallic ring (60) are mounted in a diverging region (41) of the nozzle (31) so that a corona can be maintained in the diverging region (41). Ions formed in the corona are swept out of the nozzle (31) by the supersonic gas jet. The supersonic jet ionizer (10) can be utilized as a particulate charging means in a system (75) for filtering charged particulates from a particulate-laden gas stream.

Abstract: Apparatus for generating and dispersing ions, comprises:(a) first and second tip means aimed generally longitudinally forwardly, said first tip means spaced laterally from said second tip means,(b) circuit means to supply high voltage of relatively positive polarity to the first tip means and high voltage of relatively negative polarity to the second tip means, and(c) insulative structure, including a barrier extending generally forwardly to separate positive ions dispensed generally forwardly of the first tip means from negative ions dispensed generally forwardly of the second tip means.The first and second tip means may be located in insulative, parallel tubes which are endwise open and located in the surrounding tube through which gas is caused to flow; or the barrier may comprise a plate or wall which extends forwardly of the tips.

Abstract: In an electrostatic copying machine, a charging apparatus for a photoconductive member includes a thermally responsive device for automatically adjusting the distance between the corona charger and the photoconductive member in response to temperature changes in the photoconductive member. Therefore, the charge accepted by the photoconductive member is maintained at a substantially uniform level despite the temperature variations of the photoconductive member.

Abstract: A sequential corona charging method including apparatus therefor which acts to provide several corona fields, each of its own distinct origin, which are brought together with some spatial overlap to act collectively to provide uniform charge current distribution throughout the surface of an electrophotographic medium. Independence from non-uniform charging brought about by the undesirable effects of electrostatic repulsion between adjacent electric corona fields is achieved through the rapid controlled on and off sequencing of overlapping field corona regions so that the active time coincident therebetween is negligible.

Abstract: A system for adjusting the output current of a discharge electrode for electrophotographic copying machines comprising the step of adjusting the output current of the discharge electrode in the electrophotographic copying machine by selecting a selector switch which corresponds to a class of photosensitive members, such that the discharge electrode produces an output current which is suited for the photosensitive members of the class.

Abstract: A xerographic device having a reusable photoconductor which is subjected in repeating cycles to (1) a charge corona whereat the photoconductor is uniformly charged to a negative voltage, (2) an imaging station whereat a working portion of the photoconductor is selectively discharged, to leave a charged area on this working portion defining a negative electrostatic latent image to be reproduced on copy paper, (3) a magnetic brush developing station whereat negatively charged carrier beads transport positively charged toner to the photoconductor's latent image, to leave a toned image on the photoconductor, (4) a transfer station, including a negative transfer corona, whereat a portion of the photoconductor's toned image is transferred to copy paper, (5) a positive preclean corona whereat the negatively charged photoconductor and its positive residual toner are subjected to a positive charge, and (6) a cleaning station whereat the photoconductor is cleaned by a brush having an affinity for positively charged par

Abstract: Method and apparatus for controlling static charges on dielectric material by producing an ionized field and controlling the balance and magnitude of the directional conductivity of the ionized field. The directional conductivity characteristics are typically controlled by applying a DC bias of selected polarity and magnitude to a high voltage AC output which is applied to an ionizing member to produce the ionized field.

Abstract: A system for minimizing contamination of an electrophotographic copier machine wherein toner particles and/or carrier beads are the contaminating agents. The leading edge of corona housings is positioned a substantial distance from the surface of a rotating drum so as to not affect the rotating boundary layer near the drum surface. In that manner, vortex formation within the corona housings may be prevented. The trailing edge of corona housings is given a curved shape and is at least as far removed from the drum surface as the leading edge. The system includes a vacuum scavenging chamber to remove toner particles entrained in the boundary layer. The leading edge of the scavenging chamber is given a curved shape to create a venturi in order to draw the boundary layer into the vacuum. Carrier beads are removed in the scavenging chamber since the broad curved leading edge interferes with fringe fields holding carrier beads to the surface.

Abstract: Primary charging of a moving electrographic photoconductor to a nominal potential level is achieved with low sensitivity to variation in system parameters, such as photoconductor capacitance, photoconductor velocity and/or charger efficiency. Separately-addressed, AC corona discharge units are arranged and predeterminedly biased to first substantially overcharge the photoconductor relative to the nominal potential and then discharge the photoconductor to exit at the nominal potential level.

Abstract: Corona discharge electrodes are coated with compressed dielectric materials. A corona discharge electrode is placed under tension and coated with a molten, viscous dielectric material, such as glass, while under tension. The dielectric material is allowed to cool so that the dielectric material becomes bonded securely to the corona discharge electrode. The tension upon the corona discharge electrode is released thereby causing a compression of the dielectric material adhered thereto. The resulting dielectric coated corona discharge electrode has a substantially improved life and delivers substantially uniform currents.

Abstract: In a shockless type static eliminator having pointed discharge electrodes capacitively coupled to the high voltage side of an A.C. power source and a grounded conductive member or housing adjacently spaced from the discharge points, the improvement comprising the interposing of a high voltage shield about the capacitor plates from which the discharge points project in order to minimize the capacitance between such capacitor plates and ground. The reduced plate-to-ground capacitance, C.sub.g, enables a greater portion of the supply voltage, V.sub.s, to be applied to the discharge points without increasing the discharge electrode-to-high voltage capacitance, C.sub.p, thereby permitting the use of smaller and less expensive power supply and static bar constructions.

Abstract: An apparatus for the rated charging of electrostatic layers after exposure by a corona discharge is provided, in which the primary current of the voltage transformer and/or the resistance between the corona tube and earth (housing) is varied and which comprises means for altering the position and/or the spacing of the electrode relative to the electrostatic layer.

Abstract: A corona generating apparatus for use in an electrophotographic copying machine is disclosed, which includes an elongated shield of a conductive net member defining an open ended chamber and a corona discharge electrode mounted in the chamber. The conductive net may be backed by a conventional conductive shield plate.

Abstract: A device for discharging positive or negative static electricity on an article by producing charge of opposite polarity at a sharp tip electrode. The pulse charge is produced by a capacitor triggered at a predetermined voltage to discharge through the primary winding of a transformer to induce a high voltage in the secondary winding which is rectified by a diode to give a pulse charge of the required polarity at the sharp tip electrode. A smoothing capacitor is connected across the output from the diode so that a consistent smoothed or semi-smoothed D.C. potential is obtained when the device is operated continuously. The device may be operated from the A.C. mains or from battery means.

Abstract: Photocopying machine comprising shield elements which are provided between an electrophotosensitive medium and a corona discharge unit at a transfer station, define a slit to permit transfer of conductive toner particles onto copy paper charged by the corona discharge unit but prevent imposition on the paper of a charge liable to cause early transfer of toner particles or of a charge liable to cause cancellation of the charge of the toner particles, and hence detachment, of toner particles on the copy paper.

Abstract: An improved electrographic recording system. The system includes a first charging corona for providing a distribution of charge on a surface of a recording medium representing a desired image to be recorded on the medium. The system also includes an automatically controlled second charging corona. A sensor continuously monitors the potential of a conductive layer of the medium and automatically controls the magnitude of the charge deposited by the second charging corona so as to maintain a constant potential at the conductive layer of the medium.

Abstract: There is provided a corona filament assembly which is characterized by parallel rails each having a plurality of binding posts secured thereto. Each post is formed of a button about which the filament turns and having a lip spaced from the rail and an O-ring gripping element compressibly coacting between the rail and the lip to hold the filament. The filament is wound about the binding posts in a serpentine manner and tightly retained by the O-ring.

Abstract: A method and apparatus for treating electrically charged airborne particles to reduce deposition of the particles on walls and other exposed surfaces in an enclosed area. Air containing positively charged particles exhausted from a first group of electrostatic precipitators is admixed with air containing negatively charged particles exhausted from a second group of electrostatic precipitators, the mixed air containing oppositely charged particles having less tendency to become deposited on walls and other surfaces in the enclosed area.

Abstract: An improved powder material processing apparatus is described herein, in which a plurality of wire-shaped electrodes are disposed within an imaginary plane at an equal interval and in parallel to each other. An insulator layer is interposed between the adjacent wire-shaped electrodes to prevent spark discharge from being generated by an A.C. high voltage applied between the adjacent wire-shaped electrodes. A silent discharge region is established between said adjacent wire-shaped electrodes, and positive and negative charges are separately given to the particles forming said powder material by making uncharged powder material pass through said silent discharge region, resulting in formation of powder material consisting of substantially equal numbers of positively charged particles and negatively charged particles, whereby control characteristics of the processed powder material can be greatly improved and the above-mentioned charging process can be effected continuously at a high efficiency.

Abstract: A static neutralizer which emits ions without emitting light to the environment. The static neutralizer includes a body of insulating light absorbing material, having a cavity therein, with points of ion emitters located in the cavity. A passage leads from the cavity to the exterior, permitting flow of ions from the body and preventing passage of light from the ionizing points to the exterior. A metal sleeve surrounds the insulating material body with a peripheral edge of the metal band and the ionizing points preferably lying in a common plane. A source of electric potential, preferably alternating, is connected to the ion emitters, and the metal sleeve is connected to ground. Preferably, the connections are provided by a shielded cable having an inner conductor connected to the ion emitters, an outer, flexible woven wire shield connected to the metal band, and a light impervious, insulating layer on the exterior of the woven shield.

Abstract: Conducting plates of opposite electrical potential are alternately disposed and spaced apart and immersed in a dielectric fluid in a chamber. Gas is supplied to the bottom of the chamber and passes through the fluid and over the plates. A partial vacuum is maintained in the region above the surface of the dielectric, from which the gas is extracted.

Abstract: An electrode which has at least one internal channel and an adjustable gate or slot to permit passage of gaseous material to be ionized from the internal channel and then in proximity to one or more outside faces of the electrode in a suitable area of electron emission, the electrode being placed in an electrical field in convenient proximity to an electrode or body of opposite charge.

Abstract: A two cycle process electrophotographic copying device having charging, imaging, developing, transferring, and cleaning facilities, the arrangement being in the conventional sense, incorporates a combined charge and preclean corona unit that is operable to perform either a charging function or a precleaning function at the proper time during a copying/cleaning cycle and a combined precharge/transfer corona unit. The combined charge and preclean corona unit includes a dual bay corona which emits negative and positive ions and a common control grid for controlling the ion flow from each bay of the dual bay corona.

Abstract: A grid wire for use in a duct for imparting ions in the air flowing through the duct responsive to a voltage being placed on the grid. The grid includes a housing which has upper, lower and intermediate horizontally extending supports carried therein. Laterally spaced grid wires extend between the upper and lower support members. Screw means are provided for securing the grid wires to the intermediate non-conductive support members so as to minimize the length of the free swinging portion of the wire in case the wire breaks. By making the intermediate support member non-conductive a more uniform discharge of ions is produced by the grid.

Abstract: A polarity switch circuit in a machine for electrostatically copying images from an original document image including corona charging means for imposing an electrostatic charge on a photoconductive medium, power supply means having a first output of one electrical polarity and a second output of the opposite polarity, and switch means for selectively connecting the first and second outputs to the corona charging means to selectively and alternatively impose an electrostatic charge on the photoconductive medium of the one electrical polarity and the opposite electrical polarity.

Abstract: A corona discharge device including a corona discharge electrode and a conductive shield located adjacent the electrode, the electrode being coated with relatively thick dielectric material so as to substantially prevent the flow of conduction current therethrough. The delivery of charge to the photoconductive surface is accomplished by means of a displacement current or capacitative coupling through the dielectric material. The flow of charge to the surface to be charged is regulated by means of a d.c. bias applied to the corona shield.

Abstract: An electrical discharge device comprising an insulated conductor adapted to carry a high alternating voltage and an uninsulated conductor encircling the insulated conductor.

Abstract: A method and system for ionizing air passing through a metallic duct, e.g. to maintain precise electrically neutral, positive or negative atmosphere in an area, such as a textile mill, by adding charged ions to air being pumped into that area, with at least one electrical grid mounted in the duct by means of one or more insulator posts connecting the grid to a duct wall and adapted for connection to a DC high voltage source whereby buildup of conductive material such as grease or lint in a conductive path between the grid and duct wall is prevented. In one embodiment this is accomplished by providing an insulating sleeve within the duct and surrounding the grid, this sleeve by protecting against short circuits also permitting high currents to be safely used. In a second embodiment air deflectors mounted on the grid wall deflect the air in the duct away from the insulator posts, preferably with the aid of clean air injected between the air deflectors and duct wall.

Abstract: Disclosed is a process and, to implement the process, an electrostatic charging apparatus comprising means for producing a corona discharge; a counter-electrode positioned below the discharge means adapted for supporting a recording material to be charged; means for supporting the counter-electrode, including a pair of opposed vertical side walls defining a guide channel of substantially rectangular cross-section along which the recording material can pass; and a pair of elongated strip-like members of electrically insulative material extending within the channel at least from the side walls laterally along the opposed marginal regions of the counter-electrode and longitudinally along the whole length of the counter-electrode.