Abstract: This is a method and associated apparatus for creating a 3-dimensional model by curing a photocurable liquid polymer. The method comprises first placing a quantity of the photocurable liquid polymer in a container. A substrate upon which to build the model is then placed in the container and in the polymer. A knife member is positioned over the substrate with a bottom edge parallel to the substrate at a layer-spaced distance therefrom. The knife member is then moved over the substrate and parallel thereto from a starting side edge of the model to an opposite side edge of the model while a 1-dimensional pattern of light beams for curing the liquid polymer is simultaneously created and conducted to a line at and parallel to the bottom edge of the knife member and therefrom into the liquid polymer immediately behind the bottom edge of the knife member to cure a layer of the polymer and thereby form a layer of the model.

Abstract: A digitizer includes a tablet having an array of conductors, and a pen-shaped, coil-containing stylus. The digitizer applies an energizing signal to either the conductors or the stylus, which signal induces voltages in the other. Then, the digitizer detects the induced voltages corresponding to the conductors, which define a voltage waveform having a positive peak, a negative peak, and a zero-crossing therebetween. The digitizer corrects for pen tilt in determining stylus position on the tablet by determining a position value for the zero-crossing using voltages in a region between the positive and negative peaks of the waveform and generating a pen tilt correction value using the position value and voltages in a region outside the positive and negative peaks. Then, the pen-tilt correction value and a preferably cyclic-error-corrected value for the position of the zero-crossing are combined to yield a relatively accurate pen-tilt-compensated determination of stylus position.

Abstract: This is an apparatus and associated method for rolling large pieces of a flexible media such as completed plots produced by a plotting pen plotter. The rolling mechanism is placed adjacent an exit of the pen plotter to received ejected media pieces therein. Upon detecting the leading edge of a media piece while in an open position, the mechanism closes to form a guide slot to a cylindrical rolling chamber. The media piece is then urged along the guide slot and into the rolling chamber where it is rolled by a drive roller. Upon detecting the trailing edge of the media piece, the mechanism opens allowing the rolled media piece to fall into a receiving bin. The stationary portion and the rotating portion are formed of a plurality of slats having low contact area edges disposed for media pieces to move along whereby the media pieces move along a low friction path.

Abstract: This invention is directed to the use of single optical sensor to replace two mechanical sensors in a pen plotter. A light beam is directed through a slot in the plotter's main platen. The light beam is detected to provide a signal output. Servo fan motors of the plotter are turned on when the light beam is broken by media placed into the plotter for plotting as one function. A load sequence of the plotter is started only after a start command is input by a user through a control console and the light beam is broken by media placed into the plotter for plotting as a second function.

Abstract: In an electro-magnetic, cordless digitizer system wherein a transducer emits an AC magnetic field which is detected by a first grid of scanned parallel first wires in a tablet to provide positional data for the transducer in a first axis of a coordinate system and which are detected by a second grid of scanned second wires in the tablet to provide positional data for the transducer in a second perpendicular axis of the coordinate system, a method and associated apparatus for obtaining a phase reference signal; to be used in a demodulator demodulating data signals from the first and second grids of scanned first and second wires.

Abstract: This invention is a self-adjusting motor mount for holding a driving gear mounted on the shaft of a motor in engagement with a driven gear carried by a back plate disposed in a vertical plane and is particularly useful in a pen plotter. There is a mounting plate carrying the motor and the driving gear. A pivotal mounting carried by the back plate attaches the mounting plate to the back plate at a point above the motor for pivotal movement so as to have the motor pivotally hang from the point. There is a bias spring for resiliently urging the mounting plate to carry the driving gear into engagement with the driven gear. Finally, there is a shock absorber carried by the back plate for absorbing pivotal gear disengaging movement of the mounting plate.

Abstract: This is a method and associated apparatus for employing a non-regulated voltage input to a DC driver normally outputting a voltage having a curve with a dead band and a variable slope which is a function of the non-regulated voltage input to produce an output to a DC precision positioner from the DC driver which has a constant slope and no deadband. It is particularly useful in pen plotters.

Abstract: A loopback conductor arrangement for a digitizer grid employs rotation sequencing of the conductors. The conductors in each of the X- and Y-directions are looped back and forth in a parallel, spaced relationship across the active grid area so as to provide a plurality of crossing conductor segments, with the positions of selected conductors (e.g., alternate conductors) in each successive loop shifting in sequential positions by a constant offset with respect to the other conductors in those loops.

Abstract: This invention is directed to simplified menu display and inputting apparatus for use in a pen plotter having a set of up, down, left, and right control buttons used for pen control. There is an alpha-numeric display for displaying menu choices, an ON LINE button for placing the plotter in an on line mode of operation wherein the pen control buttons are employed in their normal manner, and a MENU button for placing the plotter in a menu input mode wherein the pen control buttons are employed to move from top to bottom through top level menu definitions and from left to right through subfunction menu definitions. Displayed menu choices are selected for insertion into a current parameter value list while in the menu input mode. Provision is made to identify a number of users and store their operating parameters separately and individually so that users can return and use the plotter with their values without having to re-enter them each time.

Abstract: This invention maintains a selected printed ink drop density in an image recording device such as an X-Y plotter having a cartridge of the type which emits discrete ink droplets onto a recording medium and wherein the cartridge is transported along two axes with respect to the medium. There is sensing apparatus for sensing the two-dimensional velocity vector of the cartridge and control apparatus for regulating the rate at which the cartridge emits the droplets in accordance with the two-dimensional velocity vector. Thus, a given printed dot density on the medium is maintained for different angles of travel of the cartridge.

Abstract: A battery powered oscillator in a freely movable pointer drives a coil and a divider. A grid of spaced conductors in a base unit is inductively coupled to the coil. A conductive plate that lies parallel to the conductor grid capacitively couples the signal from the divider to a phase locked loop to provide a reference signal that has a constant phase in relation to the oscillator. Detection circuitry uses the signals induced in selected grid conductors and the phase reference signal to determine the location of the pointer relative to the conductors. As an alternative to the phase locked loop, the signal induced in an idle reference conductor can be combined with the capacitively coupled reference signal to aid in demodulating the induced signals. As an alternative to an oscillator in the pointer, the coil may be driven by a signal capacitively coupled from the base unit.

Abstract: This invention is a two-color unitary application and vacuuming head for a liquid toner electrostatic printing system. There is a body having three planar faces angularly displaced from one another concentrically about a pivot point, one of the faces being a first toner face having openings therein communicating with a first network of toner passages in the body, a second of the faces being a second toner face having openings therein communicating with a second network of toner passages in the body, a third of the faces being a vacuum face also having individual openings therein communicating respectively with a third network of toner passages in the body and with a fourth network of toner passages in the body.

Abstract: The invention is a digitizer circuit in a peripheral system for a computer comprising a moveable instrument and a planar grid in which an excitation signal in one of said instrument and grid generates an induced signal in the other one of said instrument and grid, and wherein the phase difference between said excitation and induced signals is indicative of the position of said instrument with respect to said grid, comprising means for summing said excitation and induced signals to produce a sum signal and means for producing an output signal whose frequency is a function of the amplitude of said sum signal.

Abstract: This invention is a control system for controlling an electrostatic printer/plotter electrostatically generating an image on a recording media being driven by a transport motor over a plurality of image-forming electrodes by applying image writing pulses to the electrodes. There is a media sensor for sensing which one of a plurality of pre-determined media types is currently being used in the printer/plotter and a sensor for measuring a parameter related to conductivity of the media. There is also a microprocessor for determinnig from the conductivity and type of media currently being used in the printer/plotter an optimum pulse width for the image writing pulses which maintains the density of an image produced on the media by the electrodes at a maximum density and for generating images employing image writing pulses transmitted to the electrodes which are of the optimum pulse width. Pulse repetition rate and media speed are also regulated in an optimum manner.

Abstract: A driving grid is driven by an ac signal comprising a carrier frequency modulated by a lower frequency. An untethered, batteryless pointer includes a pick-up coil in a first tuned circuit tuned to the carrier frequency, connected by diodes to a driving coil in a second tuned circuit tuned to the lower modulating frequency. Energy picked up by the first tuned circuit from the driving grid at the carrier frequency drives the second tuned circuit at the modulating frequency. Modulating frequency signals induced in the receiving grid conductors are used to locate the pointer in the usual manner. Because the carrier signal contains no frequency component of the modulating signal, the driving grid and receiving grid are sufficiently decoupled.

Abstract: An apparatus such as a printer or a plotter feeds image-receiving media such as paper by rotation of a shaft, and a media position sensor responds to the rotation of a sensor roller. The apparatus includes a position sensor calibration device having an elastically deformable ring compressible between the shaft and the sensor roller and a calibrator for changing the distance between the shaft and the sensor roller so as to change the amount by which the deformable ring is compressed, in order to adjust the output of the media position sensor for a given amount of media movement. The shaft is connected to one of a pair of media-gripping pinch rollers, the one pinch roller being rotatable by the shaft, and a shaft motor is connected to the shaft. The ring is pinched between the shaft and the sensor roller. The calibrator is a screw threaded through a stationary threaded support and extending toward the sensor roller to push the roller toward the shaft and compress the elastically deformable ring.

Abstract: This is a method and associated apparatus for electrically connecting a coaxial connector plug having a hollow cylindrical center pin inside a cylindrical conductive housing concentrically disposed about the center pin with an insulating support separating the pin and the housing to a coaxial cable having a center conductor inside a hollow conductive shield and separated therefrom by an insulating layer without the use of solder.

Abstract: In a digitizer tablet system employing a tablet having equally spaced parallel grid wires disposed in a plane along an axis parallel to the tablet's upper surface and a pen cursor having a sensing coil disposed concentric with and perpendicular to a longitudinal axis of the pen cursor to develop a characteristic output waveform from electromagnetic inductance between the grid wires and the sensing coil, this invention is the method of compensating a calculation of the position of the pen's tip on the tablet's upper surface and along the axis determined from an interpolation of the characteristic output waveform to find its zero voltage crossing point for tilt of the pen cursor longitudinal axis from perpendicular to the tablet's upper surface comprising using voltage values from grid wires next on opposite sides of the zero crossing point to calculate a pen tilt compensation factor.

Abstract: A method and associated apparatus for frictionally compensating a vector plotter having an X-drive motor for driving plotting apparatus in +X and -X directions and a Y-drive motor for driving plotting apparatus in +Y and -Y directions and logic for applying positive and negative electrical drive currents to the respective motors to affect plotting. Plotter accuracy and associated plot quality are improved by the method which comprises the steps of, providing a memory for holding +X, -X, +Y, and -Y friction compensation factors; prior to the time of plotting with the vector plotter, calibrating the plotter by (1) causing the motors to move the plotting apparatus in +X, -X, +Y, and -Y directions, (2) measuring the friction during the +X, -X, +Y, and -Y directional movement, and (3) calculating and storing the +X, -X, +Y, and -Y friction compensation factors in the memory.

Abstract: The method of manufacturing an electrostatic printhead or the like. Conductive surfaces are applied to both sides of an insulating substrate. Unneeded portions of the conductive surface are etched away by a photolithographic process to form conductive layers in patterns of parallel, spaced, printwire traces and connective conductors with ends of the printwire traces terminating in a common plane defining a printface of the printhead. Additional conductive material is added to the printwire traces by an additive plating process to give them a substantially square cross-section. The edge is laser trimmed to form the print face. Insulative layers are added over both sides with vias located over the connective conductors at places where electrical connection is to take place.