Patents by Inventor Lam F. Wong

Lam F. Wong has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5253862
    Abstract: A sheet handler for successively transporting sheet-like material units to and from processing stations in image processing devices such as printers, copiers, and scanners. The sheet handler includes an idler and driven cross-roller set. The rollers are preloaded so that a normal force exists between the rollers at the nip. The nip is positioned in a path for receiving the sheet like material units and to urge such units along the path and into alignment along a registration edge. Apparatus for adjusting the preloaded force are provided to thereby adjust the normal force on sheet-like material passing through the nip.
    Type: Grant
    Filed: December 23, 1991
    Date of Patent: October 19, 1993
    Assignee: Xerox Corporation
    Inventors: Thomas Acquaviva, Vinod K. Agarwal, Robert P. Siegel, Lam F. Wong
  • Patent number: 5248027
    Abstract: A method for controlling lateral positioning of a longitudinally moving endless belt having at least two targets aligned with tolerances on a longitudinal fixed reference line, in which belt displacement from the fixed reference line is measured at least two times during each revolution of belt movement to provide a current value of measured displacement and at least one prior value of measured. The current value of measured displacement and the at least one prior value of measured displacement are averaged to provide a current average value of measured displacement and a current average value of measured displacement is calculated for each successive current value of measured displacement to provide a belt steering correction factor used to steer the belt as necessary to reduce the current average value of measured displacement to zero. Each of the targets is preferably an apertured pattern of N-shaped configuration formed in the belt.
    Type: Grant
    Filed: December 18, 1992
    Date of Patent: September 28, 1993
    Assignee: Xerox Corporation
    Inventors: Jacob N. Kluger, Ssujan Hou, Lam F. Wong, Stephen C. Arnone
  • Patent number: 5225877
    Abstract: A control method and apparatus for tracking an endless belt. The tracking apparatus includes a roller and a belt steering roller. A span of the belt defined between the roller and the belt steering roller travels in a plane and both the roller and the belt steering roller are adapted for rotational movement about longitudinal axes perpendicular to the plane. The belt steering roller is also capable of a tilting movement through a midpoint of the belt steering roller in a soft tilt axis intersecting the longitudinal axis. A tilting mechanism including a solenoid and a spring controls movement of a yoke for tilting the steering roller about the soft tilt axis to either a positively tilted position relative to the plane or to a negatively tilted position relative to the plane. An optical sensor senses the lateral position of the belt and produces an electrical signal representing the lateral position.
    Type: Grant
    Filed: June 12, 1992
    Date of Patent: July 6, 1993
    Assignee: Xerox Corporation
    Inventor: Lam F. Wong
  • Patent number: 5218405
    Abstract: An apparatus for mounting a photoreceptor drum so that the imaging surface thereof remains at a substantially constant distance from an imaging source to minimize image distortion caused by drum runout. The photoreceptor drum is mounted on a rotatable supports and is resiliently urged against a guide. By urging the imaging surface of the photoreceptor drum against a rotatable guide, the imaging surface is maintained a substantially constant distance from the imaging source thereby minimizing lateral magnification error caused by drum runout.
    Type: Grant
    Filed: June 29, 1992
    Date of Patent: June 8, 1993
    Assignee: Xerox Corporation
    Inventor: Lam F. Wong
  • Patent number: 5208796
    Abstract: A method and apparatus 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 are of a pattern defining a reference line and a line inclined with respect to the direction of belt travel so that the duration of time between passage of the target lines with respect to a spacially fixed sensing axis will vary with lateral displacement of the belt. The targets may assume a variety of specific patterns and the invention is applicable to single and multi-pass image exposure systems as well as to both modulated laser and light emitting diode types of exposure devices.
    Type: Grant
    Filed: January 3, 1991
    Date of Patent: May 4, 1993
    Assignee: Xerox Corporation
    Inventors: Lam F. Wong, Stephen C. Arnone, William J. Nowak, Daniel W. Costanza, Jacob N. Kluger, Ssujan Hou, Lloyd W. Durfey
  • Patent number: 5156392
    Abstract: An apparatus in which a sheet is registered during the movement thereof. The sheet is moved along a path in a forward direction of movement and a lateral force is applied thereto. The lateral force causes the sheet edge to engage a moving registration edge at which time the lateral motion is discontinued and the sheet continues along its path with virtualy no loss of velocity. As a result of the movement of the registration guide the relative velocity between the sheet and the guide is zero thereby substantially eliminating wear to the guide.
    Type: Grant
    Filed: October 10, 1991
    Date of Patent: October 20, 1992
    Assignee: Xerox Corporation
    Inventors: Lam F. Wong, David M. Attridge
  • Patent number: 5138178
    Abstract: A non-contact, transmissive energy sensor is utilized for determining the thickness of paper sheets in a feed path. The sensor includes an energy emitting source and an energy detector, the output of the energy detecting source being proportional to the amount of energy received by the energy detector. The signal output level of the detector is utilized in a model to determine the basis weight of paper in the detecting zone of the detector. Heuristic sampling techniques can be utilized to reduce or eliminate the effects of images printed on the paper and flutter of the paper as it moves. An automatic calibration routine utilizing boundary coefficients is used to calibrate the paper basis weight detection system. The paper basis weight determination is utilized to control subsequent operations to which the paper sheet is subjected in order to optimize image quality and sheet handling, and to control finishing operations.
    Type: Grant
    Filed: December 17, 1990
    Date of Patent: August 11, 1992
    Assignee: Xerox Corporation
    Inventors: Lam F. Wong, Stephen C. Arnone, Jacob N. Kluger, David M. Attridge, Lisbeth S. Quesnel, Paul J. Degruchy
  • Patent number: 5083164
    Abstract: An apparatus in which successive developer units are moved to a development zone to develop, with different color toner, successive latent images recorded on a photoconductive member. At least four developer units move in unison with one another to index successive developer units into the development zone. The developer units translate horizontally to develop successive latent images. The first developer unit, third developer, fourth developer unit and second developer unit are indexed sequentially into the development zone to develop the first, second, third, and fourth latent images, respectively.
    Type: Grant
    Filed: March 11, 1991
    Date of Patent: January 21, 1992
    Assignee: Xerox Corporation
    Inventors: Venkatesh H. Kamath, Lam F. Wong
  • Patent number: 4919318
    Abstract: Side registration is provided for a web during its forward movement by lateral movement of the web causing one side edge of the web to engage a registration edge guide, by moving the web sideways with self-skewed pivotal rollers engaging and driving the web at their nip. Two separate roller drive systems with a slight speed differential are utilized in cooperation acting on the same web. A downstream, fixed nip, non-slip, roller drive system drives the sheet in its primary direction of movement, at a first driving velocity. Simultaneously, the same web is driven at an upstream position by a pivotal nip drive roller system. This upstream (pivotal nip) roller system is mounted on a pivot arm to pivot therewith, and is driven at a second driving velocity which is slightly lower than the first driving velocity of the other, downstream, roller drive system.
    Type: Grant
    Filed: April 18, 1988
    Date of Patent: April 24, 1990
    Assignee: Xerox Corporation
    Inventor: Lam F. Wong
  • Patent number: 4836527
    Abstract: Side registration of a moving sheet against a registration bar or abutment line may be accomplished by a roll nip that is slightly angled toward the registration line, and is thereafter self-pivotable from that angle to one angle nearly in alignment with the direction of sheet travel. The roll nip is spring urged toward the angled position, and moves toward the alignment position in response to the reaction force of the sheet when it engages the registration bar. More specifically, side registration and deskewing of a delicate or flimsy sheet is provided by driving the sheet sideways (transversely) against a side registration edge guide in the sheet path while the sheet is primarily being driven downstream by a roller drive system comprising a mating pair of rollers on opposite sides of the sheet path to form a non-slip nip engagement of the sheet. The rollers are not skewed relative to one another.
    Type: Grant
    Filed: April 18, 1988
    Date of Patent: June 6, 1989
    Assignee: Xerox Corporation
    Inventor: Lam F. Wong
  • Patent number: 4637581
    Abstract: A four point self-leveling support for a copier having a vertically slidable spring biased leg at each corner for contacting the floor, a cable and pulley connection from each leg to a common point located within the confines of a tetrahedron, a pulley at the apex of the tetrahedron, the cable to the leg at one corner being strung around the elevated pulley, whereby depositing of the support with copier on an uneven floor surface causes the legs to project by an amount necessary to contact the floor against the tension from the other legs transmitted via the cables so that the copier is level, and locking bolts to fix the legs in adjusted position following leveling.
    Type: Grant
    Filed: September 19, 1985
    Date of Patent: January 20, 1987
    Assignee: Xerox Corporation
    Inventor: Lam F. Wong