Abstract: In a thermal printer for thermally printing on a wide media with a composite printhead comprising a plurality of standard thermal printheads and including a small diameter print roller for supporting the media adjacent the printhead, an improvement to improve print quality by preventing bowing of the print roller away from the printhead. In one embodiment, there is a first cylindrical support roller mounted parallel to the print roller in rolling contact therewith along the length thereof to oppose vertical movement or deformation of the print roller.

Abstract: In a device having a driving mechanism for moving a writing medium over a platen disposed adjacent the mechanism and having a generally horizontal table portion and a curved outer portion where the writing medium is smoothly curved from a generally horizontal supported state to an unsupported vertically hanging state an improvement to the platen for eliminating static charge buildup problems. In its simplest form, it comprises a plurality of horizontal grooves in the upper surface of at least the curved outer portion of the platen at spaced intervals. Preferably, the plurality of horizontal grooves are substantially V-shaped in cross-section so as to create, in effect, a series of overlapped plates on the surface of the platen which, in turn, cause the creation of areas of air turbulence which partially support the moving medium.

Abstract: An apparatus which records an image, such as text, onto printable media, such as paper, has a removably closable lid, a paper cutting blade mounted on an pivoting arm having an equilibrium position in which the blade is withdrawn in a safe position, and a rod actuator cooperative with the lid for rotating the pivoting arm whenever the lid is closed so as to move the blade from the safe position to an operative position adjacent a cutting block suitable for severing the media. The pivoting arm is rotatable about a pivot pin, the blade being attached at one end of the arm and the other end of the arm being lighter, so that the blade tends to fall toward the safe position under a front cover of the apparatus whenever the lid is opened.

Abstract: A control system for controlling a turret head in a pen plotter wherein the turret head and pen holder move in combination with the pen carriage to provide turret selectability at the writing site. Sensors and associated logic are provided for detecting the presence of a turret on the pen carriage, for sensing the presence and absence of pens in the turret and in the pen holder, for detecting the type of pen or other writing device being used and taking appropriate action responsive thereto, and for applying variable damping constants to the movement of the turret head. Control logic is disclosed for assuring reliable and optimum operation.

Abstract: A digitizer tablet and associated method of construction employing ink-on-glass technology. The method comprises first obtaining substrate having top and bottom surfaces. A plurality of parallel, spaced conductive ink first conductors are applied on the top surface of the substrate with the first conductors terminating in conductive ink pads adajcent a side edge of the substrate. A plurality of parallel, spaced conductive ink second conductors are then applied on the bottom surface of the substrate perpendicular to the first conductors with the second conductors terminating in conductive ink pads adjacent another side edge of the substrate. A flexible connector strip containing a plurality of flexible conductors terminating in conductive pad ends is then placed with the pad ends over respective ones of the conductive ink pads and an electrically conductive adhesive tape is placed between respective ones of the conductive pad ends and the conductive pad end's associated the conductive ink pad.

Abstract: A digitizing tablet for use in conjunction with a stylus and a digitizing circuit capable of generating signals representative of the position of the stylus on the digitizing tablet is disclosed. The digitizing tablet includes a sheet of glass that functions as the writing surface over which the stylus is disposed. On the underside of the glass, opposite the writing surface, there are lines of conductive ink that have been applied as two sets of parallel lines that intersect perpendicularly so as to form a grid. A dielectric ink is applied over the conductive ink to serve as a protective coating and an insulator to prevent current flow at the points the lines intersect. The lines of conductive ink terminate at surface contact pads also formed of conductive ink. Electrical components can be surface mounted to the digitizing tablet at the surface contact pads by the use of a solder, conductive adhesive or other conductive bonding media.

Abstract: A method and associated circuitry for use in an electromagnetic digitizer having a plurality of first grid conductors connected from a first multiplexer controlled by a first enable input to ground and a plurality of second grid conductors connected from a second multiplexer controlled by a second enable input to ground and crossing over the first grid conductors at multiple points for eliminating errors caused by capacitively coupled signals between the grid conductors at the cross over points.

Abstract: A shield for use in eliminating edge effects from an electromagnetic digitizer having an active area of a grid of wires surrounded by a peripheral area of connecting wires containing sensitive interconnecting circuitry. The shield is a pan-shaped shield of a non-ferrous metal sized and shaped to fit over the underside of the grid of wires and surrounding area of connecting wires. The shield comprises a center section disposed over the active area of the grid wires and spaced from the active area so as to provide no interference with the operation thereof and an outer peripheral shielding lip that is disposed in close-spaced, non-contacting relationship to the areas of sensitive interconnecting circuitry contained within the connecting wires. The preferred shield is formed of a single blank of aluminum sheet having peripheral edge portions thereof bent into non-connected, abutting relationship at corners thereof to form the outer peripheral shielding lip.

Abstract: A humidifying system for maintaining the moisture content of the paper at a preferred level in an electrostatic plotter. The plotter has a paper supply compartment rotatably holding a horizontal roll of plotting paper where the paper passes from the roll and through the supply compartment to a separate printing compartment. There is a powered piezoelectric humidifier for supplying cool water vapor at an outlet opening thereof. An adjustable humidistat is disposed in the paper supply compartment and operatively connected to turn the humidifier on and off as a function of the humidity in the paper supply compartment. A plastic pipe manifold is horizontally disposed across the inside of the paper supply compartment. The manifold has a closed end and an opposite end connected to the outlet opening of the humidifier. The manifold has a plurality of spaced outlet holes through sidewalls thereof along the length thereof for water vapor introduced into the manifold by the humidifier to emerge therefrom.

Abstract: In a digitizer system, a grid comprises a group of X conductors and a group of Y conductors, each such group comprising a first and second set of conductors. The first set in each group is formed by looping a predetermined number of conductors back and forth across the grid active area so as to provide a plurality of crossing conductors segments. The second group is formed by looping a different number of conductors back and forth across the active area in the spaces between the conductors of the first set so as to provide a plurality of second set crossing conductor segments alternating with said first set crossing conductor segments. Due to the differing number of conductors in the sets and their alternate looping across the grid active area, the positional and directional polarity relationships between the crossing conductor segments shift across the active area, enabling segments to be distinguished from one another and treated as if they were separate and distinct wires.

Abstract: In a digitizer system, a primary set of conductors is formed by looping spaced conductors in pairs through four quarter sections of a grid active area in such a way that the unexcited or directional polarities of each pair are different in each quarter section. A secondary set of conductors is formed by looping at least one additional conductor back and forth through the active area in the spaces between the conductor pairs of the primary set. A coil in a pen tip is movable relative to the grid, and used to inductively couple signals in the conductors of the grid. This intertwined conductor loopback arrangement permits coverage of relatively large grid active areas with a minimal number of multiplexers for switching the conductors to signal processing circuitry.

Abstract: A digitizer cursor coil for use as part of a digitizer is disclosed. The cursor coil includes a primary winding and a secondary winding concentric with the primary winding and having a larger diameter than same. The windings are connected together in series such than when they are energized, current flow in the primary coil is in a direction opposite to the direction of the current flow in the secondary coil. The digitizer cursor includes a lens assembly comprising a bottom core and a top core both of which are formed from a disk shaped transparent material. The primary winding is wrapped into a groove formed in the bottom core, the secondary winding is wrapped into a groove formed in the top core. Cross hairs and a cross hair center point are formed in the bottom core. The top core is movable relative to the top core so that when the cursor coil is energized the center point of the magnetic field formed thereby can be aligned with the cross hair center point.

Abstract: An electronic pen for a digitizer capable of providing signals to a computer for pen movement in three dimensions relative to a planar tablet. There is a hollow, pen-shaped body member having a writing tip end. A sensing coil is disposed in the body member adjacent the writing tip end and having wires thereof connectable to the computer for use in developing X- and Y-axis positional signals relative to movement of the writing tip end over the surface of the tablet. A pen member is disposed in the body member for longitudinal slidable movement within the body member. The pen member has a writing tip passing out through the body member at the writing tip end and an opposite inner end. Finally, there is a linear position transducer disposed within the body member for producing on output wires therefrom connected to the computer Z-axis positional signals relative to the pressing of the writing tip end against the surface of the tablet.

Abstract: A new design for electrostatic printheads, and the like, which can be formed quickly, easily, inexpensively, and reliably employing wire bonding techniques. The preferred method disclosed is a method for simultaneously making two electrostatic printhead portions each having a row of dot-producing conducting printwire ends at a planar print face. A pair of printed circuit boards containing a plurality of parallel, spaced, flat, conductor strip ends along edges thereof are disposed in a common plane with the conductor strip ends positioned opposite one another in paris. Connecting wires are then wire bonded between the pairs of strip ends. The connecting wires are then embedded in an insulating material which will adhesively bond to the printed circuit boards along the edges thereof and cure into a hard material forming the body of the resultant printhead elements.

Abstract: A method and apparatus for providing automatic paper edge finding and sizing in a graphics plotter system having a platen over which paper is moved longitudinally to create one axis, penholding apparatus moved transversely across the platen and the paper to create the other axis, and a controlled raising and lowering mechanism connected to the penholding apparatus for lowering a pen being held therein into contact with, for raising it from contact with the paper, and for providing a relative vertical position value signal. Vertical sensing apparatus is connected to the penholding apparatus for sensing the top surface of the platen. First logic is operably connected to the vertical sensing apparatus and to receive the vertical position value signal from the controlled raising and lowering mechanism for calculating and saving a plurality of values indicating the distance to the platen top surface at a plurality of spaced points across the platen.

Abstract: A digitizer wherein the transduction frequency is controlled (automatically or manually) to minimize the interference effect of sources of external AC fields, such as CRT monitors. The digitizer implements the method of operation comprising the steps of, connecting a source of a frequency higher than the frequency to be employed as the transduction frequency of the digitizer to the first input of a counter; receiving input pulses from the source at the first input of the counter; outputting output pulses which are employed to generate the transduction frequency in the digitizer at an output of the counter; selectively setting an initial count value at a second input of the counter; and, repeatedly counting from the initial count value at the second input to a terminal value, outputting an output pulse upon reaching the terminal value, and resetting to the initial count value after outputting each output pulse.

Abstract: In a multi-position graphics plotter pen carousel system employing a pen capping mechanism therein at each pen position for capping and uncapping pens held by the carousel, an improvement for allowing the sensing of pen presence at the pen positions and the indexing of the carousel with a single sensor. Each pen capping mechanism is adapted to assume a first position with a pen in the pen position and assume a second position with no pen in the pen position. A plurality of first sensible attributes are associated with respective ones of the pen capping mechanisms for exhibiting a first characteristic when a pen is contained at the associated pen position and for exhibiting a second characteristic when no pen is contained at the pen position. A plurality of second sensible attributes are associated with respective ones of the pen positions for constantly exhibiting the first characteristic.

Abstract: In a digitizer system, adjacent conductors in pairs are looped through four quarter sections of a grid active area in such a way that the unexcited polarities of the pair are different in each quarter section. A coil in a pen tip is moveable relative to the grid, and used to inductively couple signals in the conductors of the grid. The number of conductors required to span a given grid active area, and the number of multiplexers required to handle such conductors, are reduced by a factor of four. The polarities of signals induced in the conductors by the coil are selectively changed depending upon the quarter section in which the coil is located and sampled to coarsely locate the coil as being between two particular adjacent conductors. In the disclosed embodiment, a ratio of the magnitudes of the signals induced in the two particular conductors is then used to precisely locate the coil between these two adjacent conductors.