Abstract: A developer backer bar having a surface having a plurality of radii for interfacing with a noncontact developer member. The backer bar is arranged so that it can be retracted for clearance purposes when removing or inserting a xerographic CRU. Upon installation of the CRU, the backer bar is biased into position to maintain a development zone within predetermined parameters. The multiple radii surface eliminates or minimizes errors that may result from slight variations in axial alignment between the backer bar and the developer member while additionally providing low drag forces on the photoreceptor.

Abstract: A printing machine having a moving imaging surface, a projecting system for modulating a beam and projecting an image onto the imaging surface, a developer for application of toner to the image projected onto the imaging surface for transfer of the image to a medium, a method of development control including the steps of; generating a setup calibration tone curve base on a preset representative halftone patches; marking a test pattern in the interdocument zone of the imaging surface, the test pattern comprising a plurality of halftone patches; sensing the test pattern and measuring a relative reflection of each of said plurality of halftone patches in the interdocument zone of the imaging surface; entering said measured values into a matrix and correlating said matrix to a plurality of print quality actuators; generating a representative tone reproduction curve base on the matrix results; producing a feedback signal by comparing the representative tone reproduction curve to said setup calibration tone curve;

Abstract: An apparatus for developing a latent image recorded on an imaging surface, including a housing defining a reservoir storing a supply of developer material including toner. A mag roll loads a toner layer onto a region of said outer surface of said donor member. A donor member, spaced from the imaging surface, moves toner on an outer surface of said donor member to a development zone opposed from the imaging surface. A shield, adjacent to said donor member and said development zone, said shield being electrical biased to generate a toner cloud between said shield and said donor member which said toner cloud releases to the development zone to develop the latent image, in response to the movement of toner on the outer surface of said donor member.

Abstract: A method adjusting variations in toner concentration in a printing machine by first determining a pixel count of documents to be imaged. The system then provides two test targets on the imaging surface in the image area, one of the test targets having a relatively low reflectance and the other test target having a medium reflectance. The reflectance value of the test targets is sensed and the difference between the reflectance values is calculated and compared to a reference value to provide an error value. The system then to the error value and the pixel count of documents to be imaged to determine a time period of dispense for a toner dispenser.

Abstract: A hybrid jumping development system utilizing two component developer and providing an improved device for controlling developed toner mass. Toner is metered onto a donor structure and a toner cloud is formed in a development nip between the donor structure and the charge retentive surface having a latent electrostatic image thereon. The toner cloud is formed by applying an alternating potential to the donor structure so as to cause the toner particles to jump off of the donor structure. The duty cycle of the AC potential is used to control the toner cloud and thus the amount of toner developed on the charge retentive surface.

Abstract: A method and apparatus is provided for transverse registration of image exposures on photoreceptive belts subject to lateral deviation from linear travel in which targets, corresponding in location to the image areas to be exposed, are used for the detection of lateral belt displacement and to control the transverse location of exposure scan. The targets each comprise a group of three slots formed in the belt, each slot inclined by some angle .theta. with respect to the transverse process direction of belt travel so that the duration of time between passage of the slots with respect to a spatially fixed sensing axis will vary with lateral displacement of the belt.

Abstract: A development system for a reproduction machine includes a pair of augers which mix and transfer the developer mixture to a magnetic roll brush system. A supply auger having a length at least as great as said magnetic brush roll is positioned along a horizontal plane and adapted to transport developer material in a direction so as to supply said material to said magnetic brush roll. The auger has a first portion thereof having an irregular blade edge and wedge shaped paddles to eliminate auger mark print defects.

Abstract: A method and apparatus for producing within an imaging area of a charged surface and without significant banding, an array of pixel spots forming image scan lines including a start-of-image scan line. The method and apparatus include a ROS for generating an even number of light beams. The ROS includes a rotating polygon assembly having a plural number of facets `F` for each deflecting the even number of light beams onto the imaging area of the charged surface forming scanning beams for simultaneously each producing an image scan line. The method and apparatus also include a controller for controlling the even number of light beams so that a scanning beam spacing "d" is maintained where "d" is equal to `F`-1, and so that at start-of-producing the pixel spots forming the image scan lines, the beams are offset relative to the start-of-image scan line and only one-half the even number of light beams is deflected onto the imaging area of the charged surface to each form an image scan line.

Abstract: An apparatus for driving, steering and maintaining tension on a moving web, particularly in an electrophotographic printing machine of the type having an endless photoreceptor belt supported by a plurality of rolls and arranged to move in a predetermined path through a plurality of processing stations disposed therealong the belt being of the type which is supported by a plurality of rolls. A belt utility roll for driving, steering and maintaining tension on the belt adapted for rotational movement about a first axis and tilting movement about a second axis transverse to the first axis is used. The drive motor and transmission are mounted integral to the utility roll unit and tilt with the roll. An actuator tilts the roll in one of two directions to cause the belt to laterally walk along the roll to maintain the predetermined belt path.

Abstract: An apparatus for controlling the concentration of toner within a developer material of carrier and toner. The apparatus having a magnetic roll for transporting a combination of carrier material and toner particles, a donor roll for transporting toner particles from said magnetic roll to a photoreceptor transfer zone, the magnetic roll and the donor roll each having a voltage applied thereto. A sensor measures the dynamic current between the magnetic roll and the donor roll and generates a signal as a function thereof. The dynamic current between the magnetic roll and the donor roll is a function of the concentration of the toner particles and the carrier material. As a result of the sensor output signal toner particles are added to the developer sump to maintain proper triboelectric properties within the developer unit.

Abstract: A method and apparatus for minimizing image smear. A plurality of sheets are printed, each having the same test pattern thereon but varying a sheet transport speed as each sheet is printed. The sheets are then scanned by the machine and a velocity profile for each sheet is created. The velocity profile is then used to determine a standard deviation and a mean velocity which are then calculated and stored or can be plotted for each sheet. The point at which the relationship between the standard deviation and the mean results in the lowest value is the optimum speed for the subsystem being calibrated. The test is then performed on a second subsystem and repeated several times so that the optimum speeds for the pre and post transfer drives are quickly and easily determined.

Abstract: A gateless rocker inverter for reversing the lead and trail edges of a sheet includes two idler roll and drive roll nip pairs with the drive rolls continuously rotating in opposite directions. The idler rolls are attached to two ends of a coupler of a four-bar linkage which opens and closes the nips in sequence, first to drive the sheet forward and subsequently to drive the sheet in a reverse direction out of the inverter for duplexing purposes.

Abstract: A full productivity, high performance inverter apparatus includes a sheet input nip, a sheet output nip, a reversing roll nip downstream of the input and output nips, and adjustable interleaving baffles for guiding sheets of a wide variety of lengths between the input nip, output nip, and the reversing nip.

Abstract: A photoreceptor apparatus constructed of a photoreceptor belt releasably attached to the surface of a cylindrical mandrel. The photoreceptor belt is preferably attached to the mandrel by means of a slot in mandrel capable of accepting a portion of the belt and retained therein by means of a releasable key.

Abstract: An image forming apparatus having an image transfer belt for transferring a plurality of images, a first image forming station for forming a first registration indicia on the image transfer belt, and a second image forming station for forming a second registration indicia on the image transfer means. The image forming apparatus further includes a registration indicia sensor belt for sensing positioning of the first and second registration indicia, a misregistration determining portion for determining misregistration of the second image forming station based upon the positioning of the second registration indicia relative to the first registration indicia, and a correcting portion for correcting the misregistration of the second image forming station as determined by the misregistration determining portion.

Abstract: An apparatus and method is presented for forming multiple color images on separate pitches of a photoreceptor belt and for registering the images and avoiding exposure of said images on the belt seam. In one embodiment, four LED print bars each form a color image on separate pitches of a photoreceptor belt, the images superimposed on each other to form a composite color image which is transferred to an output sheet. A photosensor is placed beneath each print bar and a belt hole formed on the belt surface a few scan lines before the start of an associated belt pitch. One of the belt holes has a dimension which is larger than the other holes and its location is sensed to provide information as to the location of the belt seam. Each belt hole, as the belt rotates, is detected by the sensor which produces a signal corresponding to detection of the trailing edge of the hole.

Abstract: A smart sheet sensor control system and method compensating for degradation of an optical sensor. A reference voltage trigger level is periodically adjusted in a manner biased toward a null state indicating an absence of a sheet of paper or document in a paper location. The reference voltage trigger level is periodically adjusted by a microprocessor to always lie within a window range between the null state value and an activated state value indicating a presence of the sheet in the paper location. Since the adjustment is periodic, the microprocessor need not be a dedicated microprocessor and may be used to adjust the reference voltage trigger level corresponding to several sensors respectively sensing the presence or absence of a sheet of paper at several different locations.

Abstract: A single pass tandem color printer is disclosed which utilizes a plurality of Raster Output Scan (ROS) systems mounted within a common housing. The ROS systems produce a plurality of scanning beams which emerge from the housing along parallel paths. Each scanning beam is incident on the surface of an associated photoreceptor drum at a non-normal angle of incidence greater than zero to eliminate the reflections back along the optical path which may be present in conventional tandem scanning systems.

Abstract: A high throughput, single pass direct transfer color printer utilizing a roll web based design which simplifies tandem engine architecture by eliminating a very difficult subsystem. Improved image registration is achieved simply by position/velocity synchronization of the paper web with respect to photoreceptors of the tandem print engines. Frictional slip between the web and an overrunning vacuum transport develops web tension which in turn provides a positive contact between the web and the photoreceptors needed for good image transfer. An arcuate convex paper path increases normal forces applied to the engines which increases contact pressure, as well as increasing contact surface area of the engines and the web. A web buckle between the vacuum transport and a fuser is provided to reduce vibrational disturbances and a cutter furnishes a printout in an appropriate size.

Abstract: A single pass, polygon ROS system provides a plurality of latent images which may subsequently be developed in different colors. The ROS units are initially aligned so that each color image is precisely registered at the same relative position along the exposed area of a photoreceptor belt. The alignment is accomplished by detecting the entrance of the leading edge of an image frame into an image scan exposure area, detecting the instant location of the scanning beam along the surface of the particular polygon facet and either printing the first image information line with the next start of scan detection signal or the second image information line, depending upon whether the scanning beam is after or before the midpoint of the facet, respectively.