Abstract: A digital color printer uses different mounts for holding fibers that transport light from a distribution device to light modulators. One mount, for holding the optical fibers relative to a photosensitive surface, includes a body a body having a plurality of slots therethrough to receive the optical fibers. Each slot is provided with a funnel-shaped opening on an edge of the body. The slots are substantially parallel to each other and angled relative to the edge of the body. The slots have widths selected so that, when placed within the slots, the optical fibers form essentially linear arrays. Another mount, for grouping optical fibers to receive light from a light source, includes an element having a plurality of wells therethrough, each well connecting to an edge of the element by a respective channel section. Each channel section has a funnel-shaped section at the element edge. Each well has a shape selected so that input ends of fibers grouped in the well optimally couple light from the light source.

Abstract: An imaging apparatus modulates or gates pluralities of light beams through individual light valves, thereby providing a greater number and finer resolution of modulated light beams without increasing the number of light valves or decreasing the spacing between adjacent light valves. A two-step modulation process is used, the first step being performed by a light generator incorporating a polygon mirror that selectively illuminates selected bundles of fiber optic strands. One strand from each bundle is routed to illuminate one of the cells in a light valve array, such that when a bundle is illuminated, every cell is illuminated by a strand from the illuminated bundle. The second step of the modulation process involves controlling the light valve array to modulate the light beams formed by the illuminated strands at each cell.

Abstract: An electro-optic imager, used for exposing photosensitive media, wherein a moving drum or mirror(s) are used to obtain a scanning action, and a plurality of scanning beams is preferably used. An encoder, preferably a radial optical ruling and two or more optical interrupters, is attached to a shaft connected to the moving drum or mirrors which cause the optical scanning action. The output from the interrupters is processed in circuitry which interpolates position, generating clocks much faster than the rate of signals received by the interrupters, and responding quickly to any speed changes which might occur.

Abstract: An electro-optic imager, used for exposing photosensitive media, wherein a modulator, e.g. an array of PLZT light valves, is used to modulate one or more light beams. Temperature control is applied to the modulator to reduce or eliminate variations in response characteristics which would otherwise change the color balance of the final print from the desired color balance.

Abstract: An electro-optic imager, used for exposing photosensitive media imagewise, wherein an array, e.g. two or more linear arrays, of light sources are imaged onto a rotating drum, to produce images in bands. Apertures are used to shape the beam energies. The use of two or more linear arrays with interlaced imaging allows aperture shapes to be used which precisely control the region of overlapping exposures. With properly shaped apertures, scanning artifacts (e.g. aliasing) can be nearly eliminated.

Abstract: An apparatus and method for transferring xerographically printed information on a piece of paper (102) to an ultraviolet sensitive medium (101). The paper (102) can be optionally treated with a chemical (207) to enhance ultraviolet light transmission through the paper (102). The paper (102)/medium (101) assembly may be advanced via nip rollers (432, 433) at a predetermined rate so as to optimize time of exposure to the ultraviolet light source (410).

Abstract: An electro-optic imager, used for exposing photosensitive media imagewise, wherein a linear array of scanning elements is scanned across a portion of the image, to produce a first region or band of image or information, and then translated in a direction parallel to the linear axis of the scanning elements for another scanning operation to produce a subsequent band, slightly overlapping the previous band. The translation, relative to the photoreceptor, of the scanning array is made very reproducible by establishing the position of a moving member by reference to that of a stationary notched or indented member or members, and the resultant image is made very uniform by adjusting the data controlling the imager within the region of redundant imaging to compensate for minor but known imperfections in this stationary member.

Abstract: Transition-encoded information for a single scan line of a font image consists of flags at the addresses of all points of transition upon the scan line from black to white, and from white to black, in order to generate one scan line of the font image. This information is produced, scan line by scan line, in a system receiving the vertical position, the horizontal position, and a starting address within a font memory whereat a run-length-encoded description of a particular character font is stored. This information is developed by adding, in an adder, the initial horizontal displacement plus, in a cumulative fashion, the run-length-encoded font information for each character which appears, in some portion, upon an individual scan line. The transition-encoded information is used to control pixel by pixel image generation in an image generator equivalently to full bit-mapped control but with lower cost, higher speed of conversion, and greater flexibility in the images generated.

Abstract: Transition-encoded font image information is a form of information flagging all pixel displacement locations upon a scan line of a raster scan image generator, nominally a laser printer, whereat black to white, and white to black, transitions occur during generation of the one scan line of a font image. Transition-encoded information for plural, superimposed, font images may be combined prior to generation of a synthesis image. In this combination of transition-encoded information for generating superimposed font images the flags representing transitions must not be overwritten, there being a limit that a single scan line pixel position must either transit black to white, transit white to black, or maintain the state of the previous pixel. The combining of transition encoded information encodes transitions for these one or ones of addresses (pixels) wherein two flags would otherwise overlap so that the total transitions within the combined font information are preserved.

Abstract: Transition-encoded font image information--being a form of information flagging all pixel displacement locations upon a scan line of a raster scanning image generator, nominally a laser printer, whereat a marker, nominally a laser beam, transits from marking white to marking black, and from marking black to marking white, during the generation of the one scan line of a font image--is stored in two random access memories (RAMs) each having a nominal 10,320+ address corresponding to the 1200 pixel positions per inch across an 8.6" scan line. The two RAMs are sequentially read in parallel from the start-of-scan of the scanning marker, or laser beam. The successively read transition-encoded information is used to decrement a counter upon each black-to-white transition and to increment the same counter upon each white-to-black transition.

Abstract: Integrations of the historical numbers of times that a light beam scanned in an oscillatory course by a self-resonant galvanometer scanner does traverse so far in a first direction so as to impinge upon a Beginning-of-Trace (BOT) sensor, and does traverse so far in the opposite direction so as to impinge upon an End-of-Trace (EOT) sensor, are each used to separately control the voltage level developed in a first, BOT, electrical tank circuit and in a second, EOT, electrical tank circuit. Voltage from each tank circuit is amplified and applied to drive the self-resonant scanner, at a polarity to induce continued oscillation, during one-half of each oscillatory cycle. Amplitude and centering control thereby obtained of the sinusoidal oscillation of the self-resonant scanner is repeatable to better than one part in ten thousand between cycles.

Abstract: Random access memory (RAM) clock switching circuitry for a laser printer having a RAM for storage of microprocessor information plus storage of font information with separate clock generators is provided for use in accessing the two types of information. The switching circuitry has a switch portion for alternately connecting the clock generators to a lockout circuit portion. A lockout request signal from the laser printer microprocessor determines when clock pulses presented to the lockout circuit can be applied to the RAM.

Abstract: Circuitry for control of the level of light output from a laser diode that is adapted to direct its light output to a resonant scanning mirror including a biasing current circuit portion for providing a current level for the laser diode at a desired set point and a circuit portion connected to the laser diode which reduces the current through the laser diode by an amount that is inversely proportional to the velocity of the scanning mirror so the amount of light energy received from the scanning mirror at any portion of a scan surface covered by the scanning mirror will be the same when the laser diode is on. Another circuit portion is also connected directly to the laser diode to selectively reduce the current through the laser diode to a level that is below the laser diode threshold current in accordance with binary signals supplied to such circuit portion.

Abstract: Circuitry for controlling the amplitude of a self-resonant scanner including a first means for measuring the time to complete a number of full cycle scanner movements, a second means for measuring the time to complete a number of movements between a first fixed point and a second fixed point in the scan path and logic means using such time measurements to determine whether the scanner amplitude is greater or less than a desired amplitude and providing digital information to produce an analog signal for controlling the scanner amplitude to reduce any difference from the desired amplitude.

Abstract: Compensation circuitry for a laser printer using a self-resonant scanner wherein a clock generator (VCO) and an address counter operated between start of scan (SOS) and end of scan (EOS) signals are used in the generation of data clock signals. A flip-flop circuit is connected to receive the EOS signal and the output from a higher order bit output of the address counter to provide logic circuitry with an indication of whether the clock generator (VCO) frequency should be raised or lowered. The logic circuitry provides an input to a digital to analog means which is connected to the control input of the clock generator (VCO).

Abstract: Data clocking circuitry providing data clocking signals usable to control the output of a laser directed to a self-resonant mirror of a scanning apparatus. The circuitry selects clock signals from the output of a stable clock in accordance with a program stored in a memory and with the output of a voltage controlled oscillator (VCO) used to provide the data clocking signals with the VCO provided with a control signal based on the difference in the accumulated count between the selected clock signals and data clocking signals.

Abstract: Clocking circuitry for providing clocking signals in accordance with a preprogrammed sequence of rates. An addressable memory is included having data defining such rates with a voltage controlled oscillator (VCO) controlled via data from the addressable memory. An address producing means is controlled by the clocking signals of the VCO to provide an address signal for the memory in response to each clocking signal. The clocking circuitry is used with a moving mirror for a laser printer apparatus, the mirror having a known repetitive movement which is used in establishing the preprogrammed sequence of rates.

Abstract: A thermal print head with a plurality of spaced-apart electrical conductors carried by a support with a surface area provided at an end portion of each conductor. A common electrical conductor is provided having a thin portion for each surface area which is spaced from and essentially parallel to the surface area with resistive material disposed between the common electrical conductor and each of the surface areas. The print head provides a path for current flow and thermal flow through the resistive material in a direction essentially perpendicular to the surface areas.

Abstract: Apparatus and circuitry for positioning a mirror at a desired position includes an electric to rotary motion transducer means connected with the mirror which is controlled by a signal obtained in response to an electrical positioning signal and a feedback signal derived from the actual mirror position. An electro-optical sensing means resonsive to the actual position of the mirror provides the feedback signal. The circuitry is automatically calibrated.

Abstract: Circuitry providing a scanning threshold for a scanning apparatus in response to the output of a photomultiplier of the apparatus produced during a threshold determining scan of the field uses a first memory circuit to store a signal level indicative of the maximum light intensity sensed by the photomultiplier with a second memory circuit provided to store a signal level indicative of the minimum light intensity sensed. A threshold circuit connects with the stored signals to provide a threshold signal intermediate the two stored signal levels. An inhibiting circuit may be provided to prevent the second memory circuit from responding to signals below a predetermined level. Inhibiting circuitry and memory deletion circuitry are used to condition the memories prior to and immediately following a threshold determining scan.