Abstract: The intersheet gaps or spacings between successive sheets of copy paper for an ink jet printing system are set according to the print densities for sheets to be printed to enhance the operation of a sheet dryer within the printing system. The greater the print density, the greater the intersheet gaps such that sheets which are more heavily printed are effectively exclusively within the sheet dryer for a longer period of time and, hence, receive more of the available sheet dryer energy. The print densities are determined from image data which define images to be printed on the sheets by translating the data into the number of drops to be printed per image data word and accumulating the number of drops required to print each sheet by counting the resulting numbers of drops.

Abstract: A driving circuit for supplying a radio frequency electrical signal to the applicator section of a radio frequency dryer includes a voltage controlled oscillator, supplying a signal to an amplifier circuit. The amplifier circuit supplies an amplified signal to the applicator section of the dryer via an impedance match circuit. The signal supplied to the applicator section is compared in phase with the output of the voltage controlled oscillator and phase deviations are utilized to produce a signal which controls the frequency of the voltage controlled oscillator output, such that the applicator section of the dryer is driven at its resonant frequency.

Abstract: A jet drop copying apparatus has a print head which directs a row of jets toward a print sheet mounted on a rotating drum. The row of jets extend substantially across the full width of the print sheet and are operated under control of a printing controller to print a series of tracks extending circumferentially along the sheet. The jets are shifted laterally in synchronism with the drum rotation such that each jet is moved a distance equal to the width of one printing track during one rotation of the drum. The shifting continues until a solid print has been obtained. An illumination device is provided for illuminating a narrow strip extending across a document to be copied and projecting an image of the illuminated strip upon a row of photodetectors. Longitudinal image scanning proceeds in synchronism with the rotation of the printing drum, and there is a lateral shifting of the image in synchronism with the shifting of the jet printing tracks.

Abstract: Apparatus for illuminating a narrow transverse strip on a document. The apparatus includes a pair of laterally extending illumination lamps and a pair of trough shaped reflectors for collecting light from the illumination lamps and focussing one-dimensional images of the lamp filaments along a common line extending across the document. Each trough shaped reflector has an associated flat reflecting mirror for directing its beam of illuminating light toward the document. The two flat mirrors are rotated in synchronism for scanning the light beams longitudinally along the document. The trough shaped reflectors are moved in synchronism with the scanning movement of the beams so that the images of the lamp filaments remain in one-dimensional focus throughout scanning of the flat document plane. The illuminating light is further collected and directed toward the document by a pair of reflective side surfaces which define walls for the illumination station.

Abstract: A document illumination system adapted for use in a jet drop copier or duplicator. A pair of focussing reflectors collect illumination from two parallel line source illuminators and direct the collected illumination toward a pair of scanning mirrors. The scanning mirrors, together with a pair of side mirrors, direct narrow beams of illumination toward a common illuminated strip on the face of a document positioned on a flat document support member. The scanning mirrors are scanned in synchronism to move the illuminated strip back and forth along the face of the document, and the reflectors are concomitantly moved in synchronism to maintain an image of the illumination sources in one dimensional focus at the surface of the document. All motion of the scanning mirrors and the reflectors is produced by a single drive motor, which drives a set of interspersed timing belts to produce uniform rotary motion of the input shafts for four conjugate cam arrangements.