Abstract: The camera portion of a photocopy machine employs a vacuum platen type of transport for moving photoconductive sheets into exposure-position.The sheets are of one standard size, and are normally properly filled when imaged in one-to-one size relationship with the original, but less than the full sheet is imaged whenever a reduction mode is imposed.The photoconductive sheet is blanket charged over its entire surface before it moves to the image area and therefore, if less than the full frame is exposed, there will be large areas of residual field which will pick up toner and produce toned marginal areas, which is undesirable and wasteful. Whenever the photoconductive sheet is a master, the residual field will print the block in ink on every copy, usually rendering them unfit for use.

Abstract: An improved paper handling system includes a pair of work units which sequentially work on opposite sides of a sheet with the same edge of the sheet leading. An inverter between the two work units is effective to invert the sheet in such a manner that the edge of the sheet which leads during passage of the sheet through the first work unit will also lead as the sheet passes through the second work unit. A sheet which has been worked on, first side up, by the first work unit will also lead as the sheet passes through the second work unit. A sheet which has been worked on, first side up, by the first work unit with a head edge of the sheet leading is moved by a first conveyor along a first path into engagement with a stop member which engages the head edge of the sheet to arrest it at a first readiness position. A pusher then engages a side edge of the sheet and pushes it sidewardly.

Abstract: Exposure control for an image projecting system, particularly for a projection system in which an image is projected from an illuminated object plane through a lens and onto an image plane of a copier of the full frame exposure type. Illumination means are employed for illuminating an object plane. Transducer means, preferably in the form of a photosensor, are provided in the light path and on the image side of a lens for primarily sensing the intensity of the light incident on the image plane. The transducer means produce an output signal which varies in accordance with the intensity of the projected image, and integrating means coupled to the transducer are adapted to produce a time integral output signal of the intensity of the illumination sensed by said transducer means. Means are further provided for discontinuing the illumination of the object plane by the illumination means when the time integral output signal reaches a predetermined level.

Abstract: A conveyor is provided for accepting sheets moving in one direction from a duplicator and conveying them at an angle to the initial direction; e.g., 90.degree.. The conveyor consists of rollers of relatively large diameter arranged with close spacing so that sheets of paper will pass easily from one to the other, and entering sheets will find fairly continuous support whatever their size. The rollers are set at an angle to the desired feed path to provide an effect urging the sheets towards a side alignment stop and the construction is such that the angular roller setting may be readily made during manufacture, to act towards whichever side of the feed path is selected as the one to carry the alignment stop surface.

Abstract: Duplicating equipment is provided for printing on both faces of the same sheet or, in the alternative, making two impressions on the same face (e.g., in different colors) by means of two printing heads. Both printing heads are served with masters from a single supply point, the masters being fed in proper order and attached to the master cylinder of the appropriate printing head automatically. In one form of the invention, the single master supply point takes the form of a single master maker and converter.

Abstract: Sheet separating apparatus for separating the bottom sheet from a sheet stack while at the same time adapted to adjust to any non-uniformity in thickness of portions of the sheet as each sheet enters a nip between a friction member and a sheet conveyor of substantial breadth. The sheet separating apparatus includes a broad friction member which is biased toward engagement with a broad, load distributing conveyor which transports the sheet material. The friction member is supported in such a manner that it can tilt about an axis which is parallel to the sheet path, and thus adjust itself in accordance with any variations in thickness of that portion of the sheet which the conveyor encounters as it enters the nip between the friction member and the conveyor. This arrangement causes a uniform pressure to be generated by the various portions of the friction member upon the various portions of the conveyor, and thereby to have a more uniform effect upon the portions of the sheets as they enter the nip.

Abstract: Corona electrodes in electrostatic copying machines take the form of a fine gauge wires, and when subjected to toner an atmosphere with a high density of particle dispersion, can become covered with a deposit which impairs their effectiveness. Cleaning of such a wire is situ without danger of injury thereto is effected by periodically inducing vibrations in the wire, either by controlled mechanical plucking, or by electromagnetically or electrostatically inducing vibrations.

Abstract: Electrostatic toner powder images on copy sheets are fixed by the application of pressure alone, using sets of mating rollers so arranged that each set nips and treats a narrow track on the sheet, and also so arranged that the treated tracks have slightly overlapping margins whereby the full area of the sheet is treated in the process.