Abstract: Printers that correct for polygon phasing errors. Such printers include a raster output scanner, a moving photoreceptor, a page sensor for sensing the position of an image area, a start-of-scan sensor for sensing the start of scan, a light valve array having a plurality of electrically controlled light valves for selectively passing light, and a system controller that controls the light valve(s). The system controller initially selects one of the light valves. When the page sensor senses the beginning of a page the system controller starts selecting sequential light valves at a controlled rate. After a start-of-scan occurs the system controller stops sequencing the light valves. The light valve that passed light when the start-of-scan occurred continues to pass light. Beneficially, the system controller monitors the photoreceptor motion. If the photoreceptor motion changes the system controller then selects a light valve that moves the scan line toward the proper position.

Abstract: In a raster output scanning apparatus including a laser diode adapted to output a writing beam, a reflex circuit controls the laser diode. A sensor diode is positioned to receive a portion of light flux from the laser diode while the laser diode emits the writing beam to expose one pixel area on a photosensitive surface. An accumulator associated with the sensor diode accumulates charge created by the sensor diode resulting from light flux from the laser diode. A comparator associated with the accumulator monitors charge accumulated on the accumulator and arrests the source of light flux when the charge accumulated on the accumulator reaches a predetermined threshold level.

Abstract: An optical element for the selective scan line skew correction in a raster output scanner (ROS) of an electrostatographic printer. The optical element includes a chamber having a volume defined by parallel surfaces in substantially parallel planes containing a liquid crystal material having a variable index of refraction as a function of voltage applied thereacross. An inhomogenous electric field is generated through the liquid crystal material to produce a refractive index gradient along substantially perpendicular planes in the optical element. The ROS includes a control and feedback system coupled to a variable voltage source for applying a variable biasing voltage across the optical element to control the variable index of refraction of the liquid crystal material for selectively correcting scan line skew.

Abstract: A vacuum fluorescent printing device is disclosed having cathode filaments, a multiplexed control grid and a skewed matrix of addressable phosphor elements configured on an anode in such a fashion as to enable convenient electrical connection plus imagewise recombination of emitted light from said phosphor elements into a high resolution linear array for the purpose of directing this collection of addressable points of light onto a single line of a photoreceptor drum or belt thereby enabling a xerographic image to be generated.

Abstract: A vacuum fluorescent printing device is disclosed having cathode filaments, at least one multiplexed control grid and a skewed matrix of addressable phosphor elements configured on an anode in such a fashion as to enable convenient electrical connection plus imagewise recombination of emitted light from said phosphor elements into a high resolution linear array for the purpose of directing this collection of addressable points of light onto a single line of a photoreceptor drum or belt thereby enabling a xerographic image to be generated. A fly's-eye lens is employed as a light coupling means with the printing device.

Abstract: A vacuum fluorescent printing device is disclosed having cathode filaments, a plurality of multiplexed control grids and a skewed matrix of addressable phosphor elements configured on an anode in such a fashion as to enable convenient electrical connection plus imagewise recombination of emitted light from said phosphor elements into a high resolution array for the purpose of directing this collection of addressable points of light onto a single line of a photoreceptor drum or belt thereby enabling a xerographic image to be generated. An equipotential screen grid is located between one of said plurality of grids and the anode in order to reduce voltage swings needed for cutoff of either grid for phosphor addressing purposes.