Abstract: In a method of forming a pattern of granules on a moving asphalt coated sheet, a blend drop of first and second granules is discharged onto the sheet. The blend drop forms a granule deposit on the sheet including an inner portion of first granules and an outer portion of second granules. An apparatus for use in the method includes a nozzle having an orifice for discharging a blend drop of first and second granules onto the sheet. A first granule feed chamber is provided for feeding first granules into the nozzle. A second granule feed chamber is provided for feeding second granules into the nozzle. The first and second granule feed chambers are positioned so that the first granules are fed inside the second granules in the nozzle.

Abstract: Systems and methods are described for rapidly forming precision metallic and intermetallic alloy net shape parts directly from liquid metal droplets. A directed droplet deposition apparatus includes a crucible with an orifice for producing a jet of material, a jet destabilizer, a charging structure, a deflector system, and an impact zone. The systems and methods provide advantages in that fully dense, microstructurally controlled parts can be fabricated at moderate cost.

Abstract: Disclosed is a process of producing an optical fiber preform having a step of charging a feedstock gas in an oxygen-hydrogen burner via an electrode and hydrolyzing the same in an oxygen-hydrogen flame to produce particulates containing charged glass particulates and a step of blowing the charged particulates onto a target comprised of a seed rod or a soot body formed on the seed rod so as to cause them to deposit on the target and build up as a soot body. Preferably, the process includes the further step of reducing the magnitude of the charge of the particulates in the burner along with an increase of the diameter of the target which is formed. More preferably, the process also includes the further step of making the position facing the burner across the target an opposite polarity from the charging polarity of the particulates ejected from the burner so as to electrically attract the particulates ejected from the burner.

Abstract: A method and apparatus for performing high speed chemical treatment of v type cylinder blocks. First the cylinder bores of one bank are treated. Then those of the other bank are treated. This permits a simple but compact treating plant.

Abstract: A technique for uniformly depositing particles, especially phosphor particles, onto a display panel and an apparatus for carrying out this technique are set forth in this application. This technique relies on both electrostatically and pneumatically passing charged particles to the display panel so that a uniform coating takes place both on the flat surfaces and on the curved surfaces.

Abstract: A spray device and method for the coating of objects with powder coating material. A high voltage electrode or several electrodes are located on only one side of the coating material stream in the vicinity of a spray orifice for electrostatically charging the coating material. A first flow of compressed air is directed over the electrodes to keep the coating material from accumulating on the electrode and to shape the envelope of the sprayed coating material. A second stream of compressed air is directed at the stream of coating material to counteract the deflection of the stream by the first flow and by the effects of the high voltage. Better coating efficiency (reduced loss of sprayed powder) is achieved than with electrodes arranged on both sides of the coating material stream.

Abstract: A powder coating system for difficult to handle powders includes a powder hopper containing fluidized powder particles, a pump body connected to the hopper and having an inlet in communication with the hopper, an ejector nozzle mounted to the pump body and aimed at an outlet thereof, a second nozzle mounted to the pump body and aimed at the inlet thereof and a powder application device for receiving powder particles from the outlet of the pump body and spraying them onto an article to be coated. The ejector nozzle sprays pressurized air toward the outlet to transport powder particles along a flow path which extends from the powder hopper into the pump body via the inlet and then out of the pump body via the outlet. The second nozzle sprays air pulses at the inlet in a direction opposite the particle flow along the flow path caused by the ejector nozzle. This spray from the second nozzle creates microvibrations in the inlet of the pump body to eliminate powder particle adherence and cohesion thereat.

Abstract: A technique for uniformly depositing particles, especially phosphor particles, onto a display panel and an apparatus for carrying out this technique are set forth in this application. This technique relies on both electrostatically and pneumatically passing charged particles to the display panel so that a uniform coating takes place both on the flat surfaces and on the curved surfaces.

Abstract: A method and apparatus for forming an insulator 62 on one major surface of a uniaxial tension focus mask 25 includes the steps of: positioning a mask sheet 27, having a multiplicity of openings 42 that extend from a first major surface of the mask sheet through a main body portion thereof to an oppositely disposed second major surface, at a distance from a charging gun 72, 172 having a source 74, 174 of a dry-powdered insulative material; charging and directing the dry-powdered insulative material toward the first major surface of the mask to provide a coating of the charged, dry-powdered insulative material thereon, and providing means 70, 272 for preventing the charged, dry-powdered insulative material from extending into the openings 42 and being deposited onto the main body portion of the mask surrounding the openings and the second major surface.

Abstract: An electrostatic spray device contains a tube-like spray element (3); at least one charging electrode (12) to transfer electrostatic charges to the powder; at least one counterelectrode (44) arranged in the vicinity of the charging electrode (12), which is connected to an electrical potential (20) different from the charging electrode (12), so that it takes up at least part of the free ions generated during electrical charging of the powder; at least one ring-shaped element (44; 68; 74) which forms or carries the counterelectrode (44; 64; 74, 76) and extends around the downstream segment (72) of the spray element (3), on which it is radially supported; at least one connection ridge (78) outside the spray element (3), which carries the ring-shaped element (74) at its downstream end (79) and can be attached to the spray element (3) by its upstream end; and an electrical connection between the electrical potential connection (20) and the counterelectrode (44) by way of the connection ridge (78).

Abstract: A device electrically insulates the supply of paint for an electrostatic paint sprayer from the charged paint near the sprayer. In the electrostatic paint sprayer, the paint that is sprayed from a nozzle is charged to a high potential. Because the paint is electrically conductive, the charged paint will conduct charge toward the supply. The present invention runs the paint supply through a vessel of insulating material. The vessel has baffles with openings that divide the flow into droplets, thus creating a discontinuity in the supply stream. Charge accumulated on the interior wall of the vessel attracts oppositely charged droplets, causing them to accelerate and splatter against the interior wall. The resulting coating of electrically conductive paint on the interior wall can create an electrically conductive bridge that destroys the insulating effect of the device.

Abstract: An electrostatic spray gun comprising a housing (32) for receiving a replaceable collapsible container, a nozzle (39) from which fluid is to be sprayed, squeeze grip mechanism (36, 35, 34) for compressing the container to feed fluid to the nozzle and high voltage contacts (38a, 38b) for applying electrostatic potential to the fluid such that the fluid issues from the nozzle in the form of an electrically charged atomized spray, wherein the nozzle (39) forms or is fed by a resealable delivery valve having inner (11) and outer valve members (12) with fluid fed to a gap between them by the compression of the container, from which gap the fluid emerges to form the spray and the gap being closable, desirably with a wipping, fluid-cleaning action, by relative movement of the members.

Abstract: An apparatus and method including a droplet coating generator for generating a stream of electrically charged coating droplets within an evacuable chamber towards a substrate positioned within the evacuable chamber. A piezoelectric vibrator and orifice plate coupled thereto generate the stream of coating droplets. The coating droplets are urged to move in a sweeping motion across the substrate by at least one pair of opposing spaced apart electrodes powered by an electrical power supply. A uniform coating is thus produced while the evacuable chamber is maintained at subatmospheric pressure as required during typical semiconductor processing. Multiple applications of a photoresist coating may be applied by the coating apparatus without requiring that the evacuable chamber be repeatedly vented and pumped down to subatmospheric pressure.

Abstract: A magnetic recording device includes a movable body having a magnetic layer and an arrangement for writing a predetermined magnetic image on the movable body. A developing arrangement is controlled to blow a magnetic fluid onto the movable body in order to develop the magnetic fluid. The magnetic fluid is circulated except at times when the image is being developed by the magnetic fluid.

Abstract: A web charging apparatus, for use in a coating system for applying various coating liquids onto a web which has been previously charged by a static field in which conductive wires form a corona discharge electrode. The diameter of the wires is in a range of 100-200 .mu.m, and the tension of the wires is not less than 1 kg. Intermediate holding frames for holding the wires are also provided. The web charging apparatus reduces the voltage irregularities in the width direction of the web and the irregular thickness of the coating liquid in the transfer direction.

Abstract: Apparatus (74) and method are provided for electrostatically depositing particles (64) of a first material onto a sheet (18) of a second material, and for electrostatically neutralizing the residual charge. The apparatus (74) includes a particle generator (20) for aspirating particles (64) of the first material, electrodes (60a and 60b) for electrostatically charging the particles (64) to a first polarity, an electrode (75) for electrostatically recharging a portion of the particles (64) to the opposite polarity, and a depositing chamber (22) for electrostatically depositing the particles of the opposite polarity subsequent to depositing the particles of the first polarity.

Abstract: An apparatus for providing a uniform application of a functional coating to one or both sides of a moving metal strip includes an enclosed cabinet in which a corona discharge field is established between high voltage electrodes and the strip. The coating liquid and air are separately supplied under pressure to atomizing nozzles within the enclosure. The nozzles create a dense flat spray that is directed into the discharge field at an acute angle relative to the strip. The particles in the spray become charged and are attracted to the grounded strip, while those that are not charged are directed onto the strip by the force of the discharge field. The rate at which the coating liquid is supplied to the nozzles is varied in accordance with the speed of the strip to thereby obtain a uniform coating regardless of variations in strip speed or width.

Abstract: UV-hardenable reaction resin compounds are irradiated in an applicator and immediately fed to an object that is to be covered. An initial, not activated reaction resin compound is irradiated after entering an input opening in a reactor having an irradiation space, a UV-radiation source and, optionally, a reflector. Immediately thereafter the activated compound is fed to an object to be coated or to an object to be surrounded, in an open casting mold or to a closed casting mold via the exit opening, optionally via a casting canal. The method and the apparatus are particularly well suited for covering semiconductor components and for encapsulating active and passive components as well as for cementing UV-impermeable fitting parts.

Abstract: An evaporation source in which an evaporation material is vaporized and jetted through a nozzle having a gradually opening cross-section, whereby the size of atom clusters of the jetted vapor can be controlled.

Abstract: An electrostatic filament coater comprising a plurality of coating chambers arranged coaxially in spaced apart serial relation. Each of the coating chambers has a base and an apex and being generally frusto-conical in shape with an exit opening at the apex and an entrance opening at the base. All of the coating chambers except the last one are positioned with the apex being within the base of the next adjacent coating chamber. The filament is trained through the coating chambers. A plurality of electrodes are positioned within the coating chambers so as to surround the filament. A near arc-over voltage is supplied to the electrodes and a fog of particulate coating material suspended in a gas is passed through the coating chambers and axially of the filament at a velocity which results in the electrostatic deposition of the particulate matter on the filament and the exhaust of the gas and excess particulate matter from between the coating chambers and the apex opening of the last coating chamber.

Abstract: Apparatus for producing open ended plastic containers having decreased gas permeability that includes a vacuum chamber and a pump for regulating the pressure therein, an ionization source mounted in the chamber proximate the container's open end and a container holder located in the chamber. The container holder has a hole aligned with the open end and may include a shield that encompasses the exterior of the container and may include a magnet setting up a magnetic field on the exterior of the shield. In the method, a container is placed on the container holder in the chamber with the open end and hole aligned and with the shield and magnet located as described above. The coating material is vaporized and ionized so that the ionized material is deposited on the interior wall of the container.

Abstract: An electrode arrangement for a coating installation which functions with the aid of an electric field. The electrode arrangement includes a pair of electrodes for creating an electrostatic field with at least one of the electrodes being fashioned with a sharp edge or tip. The electrode is disposed in a conduit and excess pressure or a vacuum is applied to the conduit with respect to the pressure in the coating chamber of the coating installation in an area of the electrode so that the coating medium is either prevented from coming into contact with the electrode or is suctioned off through the conduit system. By virtue of the provision of the suction removal means for the excess coating medium, the conduit system can be placed in direct communication with the ambient pressure. Additionally, the electrode may be arranged in a vacuum zone of the coating chamber.

Abstract: A process and apparatus for depositing a high-quality metallic coating on a steel strip. In this process, one or several metals or metal alloys are continuously evaporated in a thermal plasma from nonoxidizing gas and transformed into the highly ionized state of the thermal plasma. Subsequently, the metal ions contained in the plasma are electrostatically deposited on the steel strip at a pressure elevated by 100 Pa to 5000 Pa relative to the ambient pressure. During coating, the steel strip is held at a uniform temperature and coated at a rate of 40 m/min to 600 m/min.

Abstract: An electrostatic fluidized bed coating method, apparatus and system utilize a vortex effect within the particle cloud to produce coatings of exceptional uniformity upon a workpiece. The vortex effect produces a secondary particle cloud and a secondary electrostatic field, which contribute to the uniformity of the deposit, and the amount of metal structure included in the unit may be minimized, also to enhance uniformity. Operation can be carried out at voltages that are significantly reduced from those required for similar systems known in the art.

Abstract: An electrostatic spraying apparatus charges particles of a coating material to be emitted and sprays the same such that they become attracted to and deposited on a travelling web substrate. Electrode plates serve to repel the charged particles to thereby even the distribution of particles deposited on the web. An air flow may be used to additionally guide the particles or prevent them from adhering to the electrode plates.

Abstract: An apparatus and method is detailed for the application of non-conductive material, generally of a powder or fine fiber form from bulk storage onto a conductive filament or plurality of filaments. A series of vibrating troughs are used to store, convey, unpack and load particulate material at a controllable rate into a gas stream traversing a converging-diverging nozzle. High aerodynamic shear in the nozzle reduces the material's size. Divergent nozzle exit geometry slows the material to speeds where electrostatic forces can predominate, as the material is injected upwardly into a chamber fitted with a cascade of conical forms. Each cone is electrified about its circumference in one or more locations, with respect to a centrally located upward moving filament. Conventional electrostatic charging and deposition on the filament is augmented by the convergent geometry of the cones. Excess material falls on the outside of the cones, and eventually downward to a recovery area.

Abstract: The present invention relates to a process and an apparatus for electrostatic application of liquids or powders on many different substances and objects, by means of a cone diffusing the substances or objects to be coated, in free fall continuously along the internal wall of a tube where a high voltage positive corona zone is produced, while the liquid or powder is prayed from a centrifugal atomizer, by which a high voltage negative corona zone is produced, so that the liquid or powder is charged negatively and is attracted by the substances or objects charged positively and sliding on the wall of the tube.

Abstract: A method and apparatus for coating optical transmission glass fibers with a resinous composition. A vessel is provided through which a glass fiber is drawn. While it is being drawn through the vessel, the fiber is spun, and a resin coating is applied. In order to maintain the air pressure within the vessel fairly constant, an exhaust vent is provided through which excess particles of the resinous composition may escape. Turbulence is thus substantially reduced preventing the fiber from swinging and allowing the particles to be sprayed smoothly. Further, the particles may be electrically charged so that they are both attracted to the optical fiber and repel one another during flight. The invention employs both of these features to produce a uniform coat on an optical transmission glass fiber.

Abstract: An apparatus and method of using the apparatus for electrostatically depositing powder on moving objects. The apparatus includes powder-spraying chamber, air-filtering units adjacent the entrance and exit of the chamber, and at least one re-ionization chamber disposed between an air-filtering unit and the powder-spraying chamber. Each re-ionization chamber has walls extending transversely to the direction of motion of the objects through the apparatus to direct powder towards the objects on which powder is to be deposited.

Abstract: A workpiece which may be made of a highly electrically insulating material is held in a spaced opposing relationship with respect to a silent discharge plate electrode to which an a.c. voltage is applied. A d.c. voltage is applied across the workpiece and the silent discharge plate electrode to form a driving electric field therebetween. Powder particles suspended in air are charged in the same polarity as that of the silent discharge plate electrode and then injected into the region between the silent discharge plate electrode and the workpiece where the electric field drives the charged particles toward the workpiece to coat it. The a.c. voltage is sufficient to repel the electrode surface confronting the workpiece and to maintain the silent discharge at a reduced level and effectively precluding deposit of powder particles on the mentioned surface. An apparatus for the electrostatic coating is also disclosed.

Abstract: Rotary devices for atomizing liquid coating material are characterized by a housing having a circular front wall, a generally cylindrical side wall and a plurality of circumferentially spaced passages formed therethrough in proximity with the juncture of the front and side walls. Coating material smoothly introduced into the housing onto the front or side wall is carried in a thin film by centrifugal force toward and into the passages for being projected therefrom and atomized, and an electrostatic field is established between the device and an article to be coated for electrostatic deposition of coating material on the article. The device is rotated at a relatively high speed, and the passages bring the coating material to the full rotational speed of the device as it is projected therefrom, whereby atomization and the quality of the coating on the article are improved.

Abstract: A triboelectric powder spraying gun is provided which can produce an increased deposition efficiency and an improved coated surface. The spraying gun comprises an earthed or high voltage-impressed conductive nozzle having, as a lining, a plastic material which possesses an electrification series remarkably different from that of a powdered paint, in which said powdered paint is transferred to said nozzle so that it is triboelectrically charged within said nozzle, and a turbulence generator arranged inside of said nozzle. The surface of said turbulence generator is coated with a plastic material possessing an electrification series remarkably different from that of said powdered paint.

Abstract: Migration imaging apparatus of the kind using a photoelectrophoretic dispersion and having an electrode moveable along an endless operative path past dispersion application and imaging zones features improved dispersion applicator structure comprising a flat-spray, atomizing nozzle adapted to form a uniform layer of dispersion on the electrode without imparting velocity perturbations to the moving electrode.

Abstract: An electrodynamic spray painting system having a spray gun (13) for spraying paint toward a workpiece (15) and an electrode (16) for causing a charge to be imposed on the paint. A high voltage waveform generator (21) supplies an oscillating voltage to said electrode (16) such that coronas of varying strengths are periodically, controllably generated.This oscillating voltage enhances the spectrum of charges on the paint particles improving evenness of coverage of paint on the workpiece (15). Additionally, wastage of paint is decreased. This invention is also applicable to other coating materials, such as powders.

Abstract: A device for the electrostatic application of particles entrained in a stream of gas to a non-conductive, flat substrate, typically a web or sheets of paper. The particles are electrically neutral in the stream. A charging electrode is located below the substrate in the area where the gas stream impinges on the substrate. The substrate is advancing lengthwise, and a counterelectrode is located below the substrate in the direction of advance from the charging electrode. Preferably the direction and velocity of the gas stream near the substrate and direction and velocity of the substrate itself are approximately equal. Also in the preferred form, a grounded collecting pan is located beneath the electrodes.

Abstract: Lubricating material is applied to a fast moving strip within a vertical deposition chamber having smooth side walls and a roof slanted at an acute angle with respect to the side walls on each side of the chamber at its top. A plurality of sources of lubricating particles are spaced in each side of the deposition chamber intermediate its top and bottom. Each of the sources includes a horizontal chamber outside of the deposition chamber and opens into the deposition chamber. Each of the sources have a plurality of compressed air atomizers supplied from a supply of lubricating material in said horizontal chamber and are adapted to remove the larger particles of lubricating material from said spray and to urge the remaining smaller particles into the deposition chamber by the residual flow of compressed air from said atomizers. Lubricating particles flow slowly and without significant momentum into the deposition chamber.

Abstract: An apparatus for applying a bump-plating on one surface of a semiconductor wafer, which comprises a plurality of cup-shaped plating basins and a plurality of holders, each of the holders being engageable with a relevant one of the basins to set a semiconductor wafer horizontally, in which the underside of the wafer is contacted with plating liquid vertically blown up, the respective plating basins having an annular protrusion provided on the inner peripheral surface thereof to thereby bias internally a portion of plating liquid blown up along the inner surface of the plating basin so as to contact uniformly the plating liquid to the underside of the wafer as well as to average electric field density applied on the wafer surface.

Abstract: Apparatus generates and substantially uniformly electrostatically deposits very finely divided lubricating particles onto the surface of an electrically conducting substrate. A lubricant material is sheared into droplets of various sizes. The larger particles are filtered out of a flow of particles by gravity, baffles, and other forces leaving only a cloud of extremely small particles to be deposited. Deposition occurs within a housing that includes a plurality of sections arranged longitudinally on at least one side of the substrate and includes electrode means transversely positioned in each such section. The cloud of particles is uniformly provided to each of a plurality of longitudinal sections of the substrate and permitted to drift or migrate relatively slowly between the electrodes and the substrate. The particles in the cloud are electrostatically charged by high voltage applied to the electrodes and deposited on the surface of the substrate as a uniform dispersion of spaced particles of lubricant.

Abstract: The object is electrically charged to have a first polarity. A dispersion in air of powdered coating is similarly charged to have a like, first polarity and is clouded about the object. The metal object is then suddenly provided with an opposite charge to have an opposite, second polarity, whereupon particles from the cloud are uniformly attracted to and deposited on the object. The powder composition and the technique for fusing the deposited powder to provide a continuous coating may be the same as are in current commercial use.

Abstract: An apparatus used in the electrodeposition coating of a continuous sheet of metal as it travels in a horizontal pathway between a pair of electrically charged electrodes and through a bath of liquid coating solution that is continuously circulated to the bath through a pair of liquid seals which are disposed adjacent opposing, aligned openings through which the sheet of metal enters and exits a chamber containing the bath. The liquid seals are each comprised of a pair of nozzles for directing converging streams of liquid coating solution against the traveling sheet of metal in the direction of the chamber and have a three-fold purpose.

Abstract: A method of forming a colored shade band having a relatively wide portion of essentially uniform intensity and a relatively narrow boundary portion of graded intensity by spraying a dye composition along a longitudinally extending edge portion of a non-electroconductive substrate such as a glass sheet or a sheet of plastic. In one embodiment of this invention, the substrate is sprayed to form the graded band and then laminated to a layer of plastic interlayer material to produce a laminated window having a shade band having a desired transverse pattern of graded intensity along a longitudinally extending edge portion thereof.

Abstract: An apparatus for bump-plating on one surface of a semiconductor wafer, in which the upper surface of a horizontally set semiconductor wafer that is not to be plated has a gas, blown thereon preferably with an inert gas, and the lower surface of the wafer is contacted with plating liquid that is blown vertically upward, to thereby prevent the non-plated surface from being contacted by with the plating liquid without usage of any coatings such as photoresist to being applied thereon so as to facilitate the bump-plating of semiconductor wafers.

Abstract: An apparatus for electrostatically coating conductive articles with powder. A mixture of powder and air is delivered through a passage of uniform cross-section and a short section of rotating tube to a rotating bell of nonconductive material having a surface angle with the axis of 50.degree. to 90.degree.. The powder is directed from a nozzle over the bell surface and the entraining air is dissipated laterally. The powder is discharged from the bell into an electrostatic field where the particles acquire a charge and are attracted to and deposited on the grounded articles. A pneumatic jet pump for entrailing the powder particle in an air stream has a nozzle and venturi so related that the expanding air from the nozzle blends with the expanding portion of the venturi.

Abstract: Disclosed is an electrostatic coating device and method employing highly charged particles that are charged remote from the articles to be coated and then delivered to an area where they are to be applied by conveying them in a moving air stream. The movement is stopped by closing off the air stream, suspending the particles in space. Thereafter the particles are applied to an article by electrostatics. Special components are a powder entraining device which uses air fed at the bottom to erode the powder, feeds additional air from above and removes entrained powder from below; a charging device using the reaction of two converging opposed vortexes to oscillate the powder turbulently through an isolated high voltage electrical zone; and a multiple valve that feeds the charged powder to a can and vents the can, then isolates the can, bypassing the powder.

Abstract: Objects moving through a coating chamber are coated with particles, flakes or fibres in a uniform manner as a result of the particles, flakes or fibres being fed to the coating chamber by a conveying system which includes a vibrating feeder box, a gravity duct, a vibrating conveyor channel, a T-shaped distributor body and a transducer located below the distributor body. The transducer includes insulated wires on the bottom leg thereof that convey an alternating current and electrodes which are capable of carrying a direct current to the moving objects to be coated which are themselves grounded. When the particles, flakes or fibres drop from the T-shaped distributor body to the vicinity of the transducer they become influenced by the alternating electrostatic field and rise up in swirls. They then become influenced by the direct electrostatic field between the electrodes and the objects to be coated and they move along the lines of flux to coat the objects uniformly.

Abstract: A power grid for a fluidized bed for electrostatically depositing a powdered plastic coating material from the bed onto an elongated metal substrate moving in a path of travel above the upper surface of the bed on a substantially horizontal pass line. The power grid includes two co-planar wire mesh elements positioned beneath the surface of the bed, the elements having opposed edges in parallel spaced relationship and defining a gap therebetween beneath the pass line. The edges are upturned to form a plurality of electrode segments, the tips of the electrode segments being substantially coincident with the upper surface of the bed when energized. In operation the electrode segments form a row of localized corona discharges to either side of the passing substrate to effect electrostatic deposition of a thin uniform film coating of the powdered material thereon.

Abstract: Electrostatic printing or coating apparatus including a main drum for transporting developer mix to an application or printing zone and having permanent magnet segments mounted within the drum for attracting developer mix to its exterior surface. An electric field is produced in the printing zone to provide movement of developer particles toward the article to be printed or coated and a field producing electrode is mounted within the drum adjacent the printing zone. A container conveyor extends past the printing zone to provide positioning of container portions to be coated, and a further drum having interior permanent magnet segment is positioned to remove developer mix from the main drum. The further drum may be rotated in the rotational direction opposite that of the main drum to reduce developer turbulence.