Abstract: A barrelless gun for use with a microballistic printer to propel balls toward a printing medium in which the ball next to be fired is releasably held in a resilient breech with gas under pressure supplied to the region behind the breech and with the region in front of the breech extending to the medium being unobstructed so that no element of structure affects the flight of a ball fired from the breech. Preferably the ball in the breech is fired by moving another ball into the breech to dislodge the first ball.

Abstract: A copy image size changing system for a copying machine incorporating an original scanning optical system in which a change in the size of the copy image is effected by shifting the positions of reflecting elements disposed at locations along the optical axis of the copier on opposite sides of a fixedly positioned lens. Preferably the lens forms part of a partition which separates the scanning part of a liquid developer machine in which heat is generated by the original illuminating lamp and the developing process part wherein the liquid developer is stored and the photosensitive element is located.

Abstract: The invention relates to a method of operating a microballistic printer in which successive projectiles are fired against a platen to print successive dots and the gun is moved along a path to form characters from the successive dots. In order to prevent collisions between successively fired projectiles, the gun is positioned away from a plane extending normal to and outside of the printing area of the platen. Successive movements of the gun are in a direction away from this plane toward the gun.

Abstract: A ball injector for feeding balls to the ball gun of a ballistic printer in which a ball guide or separator is provided with a passage for receiving balls, a rotary saw blade whose teeth extend into the passage is driven to supply balls trapped between the teeth of the blade to the passage. To prevent jamming of a ball between one of the teeth and the passage entrance, a barrier having a resilient leading edge is disposed along the ball path portion adjacent the passage entrance. Preferably the resilient edge has a small radius of curvature and is disposed obliquely relative to the ball path.

Abstract: A combined registration, image transfer and pickoff assembly for an electrophotographic copier in which a transfer pressure roller having an elastomeric outer layer with a hardness approximating that of the copy paper is disposed across the imaging drum at a spacing from the drum greater than the thickness of the image toner layer but less than that of the copy sheet. A registration roller is urged into line engagement with the transfer roller to form a registration nip for receiving the leading edge of a copy sheet prior to its movement through the transfer nip. A selectively actuable gripper carried by the transfer roller is opened to receive the leading edge of the copy sheet when it enters the registration nip, then retracted to clamp the leading edge and carry it around with the transfer roller through the transfer nip, and reopened on the other side of the transfer nip to allow the leading edge to be peeled from the transfer roller and directed along an exit path.

Abstract: In an electrostatic copier having an applicator electrode positioned closely adjacent but not touching the photoconductive surface on which there is a latent electrostatic image to be developed. The surface of the latent image and the surface of the applicator electrode move at the same speed, or the electrode may move at a greater speed. The electrode and the photoconductor are spaced from each other by a gap in the order of between three and six mils. The applicator roller is mounted with its lower segment immersed in a tank containing a developing liquid bearing charged toner particles. There is a mechanism for increasing the liquid to the gap, such as a drive for speeding the rotary electrode to more than the photoconductor speed. After the latent image has been developed, a metering roller, which is a roller whose surface moves in the direction opposite to the surface of the photoconductor, meters or dynamically removes a portion of the liquid from the developed image.

Abstract: An improved pick-off device for a copying machine of the type in which the developed image is transferred from the surface of a photoconductor to a sheet of copy paper in which a thin semi-rigid blade having a knife edge at a transversely tapered end thereof is releasably secured to a resiliently restrained element of a clutch assembly mounted at a position at which the knife edge of the blade is resiliently biased into engagement with the photoconductor at a location in the path of the leading edge of a sheet to which an image has been transferred to guide the sheet into a narrow space between the normally stationary clutch element and a continuously driven clutch element. In response to the entry of the sheet into the narrow space the two clutch elements are coupled to cause the restrained element to move with the continuously driven element against the action of the restraining means to carry the sheet away from the photoconductor surface.

Abstract: A combined image transfer and registration system for an electrophotographic copier in which a somewhat conductive transfer roller having a surface hardness which is approximately the same as that of the copy material is brought into spaced relationship with the photoconductor surface at a distance less than the thickness of the copy material. Prior to the arrival of the leading edge of the developed image adjacent to the transfer roller a length of copy material has been fed to the nip between a registration roller and the transfer roller to permit a registration signal to initiate rotation of the transfer roller through an overrunning clutch to move the copy material into the space between the image bearing surface and the transfer roller to clutch the transfer roller to the drum to cause the copy material to move synchronously with the image as the transfer takes place. A bias potential may be applied to the transfer roller to assist in effecting transfer.

Abstract: My invention comprises a ballistic impact printer which includes a gun for successively propelling balls to a printing medium spaced from the gun. The balls are fed to the printer from a reservoir and recycled to the reservoir after they have performed their impact-printing function. I provide a bleeder duct for the projectiles intermediate the projectile feeder and the gun. When no printing occurs, the balls are deflected to the bleeder duct and never reach the gun. When printing is desired, the bleeder duct is blocked in order to constrain the projectiles to be fed to the gun, past a deflector which normally diverts the projectiles to the bleeder duct. The gate is a rapidly acting, electrically actuated assembly employing a piezo crystal or crystals, an electromagnet, or a solenoid. The deflector is positioned in the feeding duct and may be spring-loaded so it will yield when the gate is closed.

Abstract: A deformable polyurethane roller, which may be either a squeegee roller or a blotting roller, is positioned to contact a liquid-developed electrostatic image on a photoconductor. The polyurethane roller has a resistivity of 10.sup.9 ohm-centimeters or less and a Shore A hardness of 45 or less. The roller is biased by a potential having a sign the same as the sign of the charged toner particles in a liquid developer which comprises an insulating liquid having charged toner particles disseminated therethrough. The bias on the polyurethane roller is such that it prevents streaking, smearing, tailing or distortion of the developed electrostatic image and removes so much of the liquid carrier of the liquid developer from the surface of the photoconductor that the just-moist developed image can be transferred to a carrier sheet. This enables a higher-boiling insulating liquid to be used as the carrier liquid in a liquid developer.

Abstract: My invention comprises a novel method of increasing the effective sensitivity of photoconductors to discharge by ionizing radiations by masking a latent electrostatic image formed by exposure of a subject to ionizing radiations, masking the latent electrostatic image, and then subjecting the masked electrostatic image to light exposure to increase the contrast of the latent electrostatic image. The thus enhanced latent electrostatic image is then developed by either positive or negative development, and the developed image may, if desired, be transferred to a carrier sheet. The invention reduces the Roentgen level to which a patient is exposed. One form of apparatus for carrying out this method is shown, comprising a first toning means for masking the latent electrostatic image and means for subjecting the masked electrostatic image to enhancement by flooding the same with light exposure. A second toning means for developing the enhanced electrostatic image is provided.

Abstract: A pickoff device for a copying machine of the image transfer type in which the leading edge of the copy sheet to which the image has been transferred is guided from the surface on which the image was formed and developed into the narrow space between a first continually driven clutch element and a second clutch element resiliently restrained against frictional rotation with the first clutch element in the absence of a copy sheet in the space between the elements with this space being sufficiently narrow that entry of the leading edge of the copy sheet into the space clutches the elements together to move as a unit to carry the copy sheet around to a location at which the clutch automatically releases as the leading edge of the copy sheet enters the nip between an upper metallic delivery roller and a lower delivery roller which moves with the first clutch member. Any suitable device, such as a mechanical finger, a jet of air or the like may be employed to direct the leading edge of the sheet into the clutch.

Abstract: My invention relates to a microballistic printer in which I provide a collector wall normally struck by projectiles rebounding from the platen of the printer with an anti-bounce surface. The surface comprises a thin and flexible sheet spaced from the wall to absorb or dissipate the kinetic energy stored in the rebounding projectiles. The sheet has a thickness of the order of four mils and is formed of a material having a ratio of yield strength to modulus of elasticity which is sufficiently high to prevent a permanent set in the area of impact by a projectile.

Abstract: Apparatus for removing residual electrostatic charge following image transfer from the surface of a photoconductive imaging layer such as selenium exhibiting substantially greater dark resistance to the flow of current in one direction than in the other. A resilient conductive cleaning member in wiping engagement with the imaging layer and supplied with slightly conductive cleaning liquid is supplied with a biasing potential relative to the imaging layer substrate of a polarity opposite to that of the residual charge. The biasing potential is of such a magnitude as to ensure that all portions of the imaging layer surface have discharged to the potential of the substrate within the period of contact.

Abstract: My invention comprises an improved method of electrophotography which enables me to increase the effective speed of a photoconductor. The speed at which copies may be made is a function of the quantum of light falling on the photoconductive surface and the conductivity of the photoconductor under illumination. Since the rate at which a given photoconductor discharges the surface potential on the photoconductor through the action of light is limited, speed can be increased for a given photoconductor only by increasing the illumination. This requires energy and produces heat. My process deliberately underexposes a charged photoconductor to a light and shade image of the original to produce a weak latent electrostatic image of low contrast which is insufficient to make a satisfactory copy. I then mask the latent image with a liquid-carried toner while preventing deposition of the toner on the background areas. I then discharge the background areas with a blanket illumination of low intensity.

Abstract: Apparatus for collating, stacking or otherwise sorting successive sheets of paper delivered from the output station of a sheet-delivering device, for example, from a photocopier. A compact stack of a selected number of sheet-receiving trays is lifted above the output station and the trays are caused to drop one at a time to a position below the output station such that each can receive one or more sheets from the output station. In a preferred embodiment, the trays are mounted to move between the top and bottom of a vertically movable frame in which the trays are lifted to form an upper stack from which they are successively dropped to form a lower compact stack with an intervening space into which the sheets are delivered to be deposited on the uppermost tray of the lower stack.

Abstract: A jam detector for use in a plain paper copying machine of the type in which the copy paper to which the image has been transferred from the surface of a photoconductive drum is removed from the drum by a pick-off element which acts on a narrow strip of the copy paper extending rearwardly from the leading edge of the paper along one side edge thereof wherein the leading edge of a narrow or skewed or otherwise misdirected copy paper which misses the pick-off element is engaged by a jam detector element positioned in the path of the paper a predetermined distance inboard of the pick-off element to cause the jam detector element to disable the machine and to illuminate the jam indicating signal light. The arrangement is such that the machine cannot be reset for the next operation until such time as the jammed copy paper is removed from the machine.

Abstract: A control system for a copying machine having a scanning optical system and main and auxiliary supplies of copy paper of different size and adapted for use with a collator having a back bar, in which a signal which is produced when the machine is turned on automatically sets the machine to feed paper from the main supply and sets the initial scan to the length of the longest copy and in which a signal which is a measure of the length of the first copy being made in a given operation sets the length of the scan and positions the collator back bar in accordance with the length of the first copy.

Abstract: An electrophotographic liquid developing system for overcoming the effect of photoconductor background potential in which during the passage of the image area through the developer unit a constant current source supplies a small current to the development electrode to raise the electrode to a potential of the same polarity as and of a magnitude greater by predetermined amount than that of the average background potential of the image area in a preferred embodiment the constant current source is provided by a small plate mounted in and insulated from the transfer corona housing and having such dimensions as to provide the required current. Preferably, the output of the constant current source is controlled in response to a measurement of the conductivity of the developer.