Abstract: A toner system for delivering powder toner from a storage hopper to an element carrying an electrostatic pattern of charge to be toned before transfer to a receptor such as paper includes a scavenger which, when coupled to the toner system can be actuated to develop a slight negative pressure in the toner system sufficient to entrap flow enhancers such as zinc stearate and to remove the non-magnetic zinc stearate from the toner system. The scavenger includes baffles for collecting particles and means for developing the negative pressure in the toner system.The toner system also includes a pair of magnetic clips for positioning on the metering blade of the toner system to define the width of the toner path being transfered from the toner system to the electrostatic image on the dielectric surface and a cleaning device which periodically moves along the metering blade to clean the front of the metering blade of any accumulated toner.

Abstract: This invention provides an electrostatic printing apparatus comprising a rotatable electrostatically chargeable drum and ion deposition means for forming an electrostatic image on the electrostatically chargeable drum, the improvement comprising means for discharging a flow of air along the path of flow extending between the periphery of the electrostatically chargeable drum and the ion discharge means.

Abstract: A toner feeder is provided for use with a magnetic roller to tone electrostatic images. The feeder includes a doctor blade attached to an adjustable block for varying the gap between an edge of the blade and the magnetic roller. The block and blade combine to define a recess above the blade and toner builds up in the recess to present a living wall of toner. This reduces agglomeration and build up of toner lumps. The invention is particularly useful with toners requiring relatively low fusing pressures.

Abstract: Apparatus is provided for printing on a receptor such as paper. An electrostatic image is formed on a dielectric-coated drum in a controlled environment to minimize the creation of chemical contaminants. The image is then toned by wiping toner over the image from a toner delivery system which includes a mouth shaped to cause a vortex in the toner to improve toner flow. After toning the image is transferred to the receptor under pressure from a roller which is skewed with reference to the drum. The pressure in the nip is sufficient to also cause the toner to be fused to the receptor. An image eraser is also provided in the controlled environment.

Abstract: Apparatus for processing a digital raster scan signal for use by an electrostatic printer having a print cartridge with an ion deposition matrix composed of sixteen drive electrodes intersected by 128 finger electrodes is described. A digital input signal, representing a line of raster scan data, is reformatted to be compatible with this print cartridge. This is achieved by reformatting the signal into sixteen data groups, each containing 128 bits and storing at least sixteen data groups at any one time in a memory. A motion control circuit responds to signals from the memory circuit, from the rotation of the drum and from paper sensors to effect scanning of the ion deposition matrix in a timed sequence. One of the drive electrodes and all 128 finger electrodes are energized by one data group at any one time to effect ion deposition as the drum rotates, then the next drive electrode and the next data group are energized. This is repeated until the entire matrix is scanned.

Abstract: A corona charging device including a dielectric-coated elongate conductor contacting or closely spaced from a grid electrode, mounted against an insulating support. A high voltage varying potential between the elongate conductor and grid electrode induces a glow discharge in the vicinity of the dielectric-coated electrode. The grid electrode may act as a ground plane to provide a corona discharge device with respect to a proximate member. Alternatively, the grid electrode may be maintained at a desired potential to provide a charging device with an automatically limited voltage.

Abstract: Method and apparatus for duplex electrostatic imaging wherein a toner image is transferred and simultaneously fixed to two sides of a receptor medium using high pressure. The first toner image is created on a dielectric image roller and pressure transferred to a transfer roller moving at an identical surface velocity. A second toner image is subsequently formed on the image roller, and the two images are simultaneously transferred and fused to opposite sides of a receptor sheet at the nip. The image roller advantageously includes a hard, very smooth dielectric surface, while the transfer roller has a moderately smooth, compliant surface. The transfer roller surface preferably comprises an engineering thermoplastic or thermoset material characterized by a relatively low coefficient of friction in order to provide high transfer efficiency to the receptor sheet. The duplex imaging apparatus may be incorporated into electrostatic printers and copiers with suitable adaptations in the image generating stages.

Abstract: A corona charging device including a dielectric-coated elongate conductor embedded in a slot in a conductive member. A high voltage varying potential between the elongate conductor and slotted conductive member induces a glow discharge in a region of proximity of the two conductors. The slotted conductor may act as a grounding member to provide a corona discharge device with respect to a proximate surface. Alternately, the slotted conductor may be maintained at a desired potential to provide a charging device with an automatically limited voltage. The slotted conductor and dielectric-coated conductor may be replaced with alternative structures which provide an equivalent enclosure.