Abstract: A lead loader mechanism for a pencil plotter in which a lead stocker contains a plurality of leads for use in a pencil plotter, at least one lead actuator mechanism is coupled to the lead stocker and is adapted to release the leads, and a support is provided for holding at least one lead holder and for engaging the lead actuator mechanism to release the leads into the lead holder. In a particular embodiment, the lead stocker has at least one lead storage chamber therein and the lead actuator mechanism is mounted on the lead stocker below the lead storage chamber and is adapted to be changed from a first condition in which the leads are prevented from leaving the lead storage chamber to a second condition in which the leads are free to leave the lead storage chamber, and the support is adapted to cause the lead actuator mechanism to change from the first condition to the second condition.

Abstract: Methods and apparatus for setting the signal-sampling period of each grid wire in a digitizing tablet having grid wires that are sequentially and repetitively scanned to develop a positional signal related to a cursor so as to reduce jitter associated with non-movement of the cursor and signal error associated with rapid movement of the cursor. The method comprises setting the signal-sampling period of each grid wire to a longest signal-sampling period the digitizer tablet is designed to employ if the cursor is not moving and setting the signal-sampling period of each grid wire to a value inversely related to the present speed of movement of the cursor such that the faster the present speed of movement of the cursor the shorter the signal-sampling period of each grid wire as compared to the longest signal-sampling period the digitizer tablet is designed to employ. The present position of the cursor is then saved as the prior position of the cursor for the next time the steps of the method are performed.

Abstract: This is a method and apparatus for use in the "color-graphics board" of a computer having a pictorial output visualizable in color. It is particularly suitable for use with computers of the Macintosh type of configuration, but is by no means limited to computers of that type. The invention affords to the operator of the computer the ability to select various bit levels for the pixels which together comprise the display of the computer. The bit levels may be selected at will depending upon the necessary degree of resolution and color selectability that characterize the diverse possible uses of the visual display of the computer.

Abstract: A media loader for a media roll having a pair of endcaps. The media loader has a handle portion, a support portion adapted to partially encircle the endcap and a flexible midportion having an opening narrower than a selected portion of the endcap and adapted to flex to allow the passage therethrough of the selected portion of the endcap. The support portion is substantially the same cross-sectional size as the selected portion of the endcap but is adapted to remain stationary when the endcap rotates therein. The handle portion is adapted to accept therethrough portions of the endcap of larger cross-sectional size than the selected portion of the endcap while the flexible midportion is sufficiently stiff so as not to flex under the weight of the media loader.

Abstract: A lead positioner for a pencil plotter in which a lead stocker contains a plurality of leads for use in a pencil plotter, a lead actuator mechanism is coupled to the lead stocker and is adapted to release the leads into a lead holder, and a shaker is provided coupled to the lead stocker and adapted to enable the leads to be released individually into the lead holder. In a particular embodiment, the shaker imparts a vibrational motion to the lead stocker prior to the lead actuator mechanism releasing the leads to enable the leads to be released individually. The shaker is further adapted to provide a translational motion to the lead stocker to align the leads and the lead holder and, in addition, to enable the lead actuator mechanism to release the leads into the lead holder.

Abstract: An ink sensing system for a vector plotter in which a pen is adapted to be raised and lowered from a drawing media surface along a system axis. An optical detection system is provided which has a focal point on the system axis and below the media surface when the pen is in its lowered position and at the media surface when the pen is in its raised position. The optical detection system includes a source of illumination and a detector system to determine the degree of reflectance from the media surface to indicate the presence or absence of ink on the media surface. In a particular embodiment the optical detection system is moveable and the movement of the optical detection system is coupled to the movement of the pen. Furthermore, the focal point of the optical detection system coincides substantially with the last point of contact of the pen with the media surface when the pen is in the raised position.

Abstract: The invention is a media positioning system for determining the position of the media relative to reference positions thereof in a media transporter in which media having opposed faces is transported along a path of a track including a spatially varying pattern on the media, the alignment system including a light sensor having a light-sensitive surface facing one face of the media in at least approximate registration with the track, the light-sensitive surface including plural sections, the sensor producing plural signals at an output thereof proportional to the intensity of light impinging on respective ones of the plural sections of the light-sensitive surface, a light source facing the other face of the media and directing a beam of light through the media onto the light-sensitive surface, whereby the plural signals vary as a function of the spatially varying pattern of the track as the media is transported along the path of the track, and signal detection and logic apparatus for converting the plural sign

Abstract: This is a hand cursor for a digitizing system allowing easier positioning of the cursor at the points to be digitized. The cursor includes a quasi-sight window having a CCD panel for viewing a 2-dimensional area and an LCD panel for displaying it to the user. There is a vertical positioning line on the panel. A position signal generator is disposed in the cursor for continuously generating and outputting positional data from which a reference point position and the orientation of the positional line on the tablet surface can be dynamically determined. There is also position determination logic for inputting the electrical signal output from the CCD panel and the positional data from the positional generator and for determining a point on the tablet surface where the positional line crosses a line contained in a drawing disposed on the tablet surface over which the quasi-sight window is positioned as a point to digitize.

Abstract: This is a low-cost cursor for a digitizing tablet which provides the user with the feel of a mouse. There is a case bottom piece for sliding on the surface of the digitizing tablet and a pair of microswitches. A printed circuit board fits in the case bottom piece with the pair of switches mounted behind one another thereon. A transparent front-piece is disposed over the printed circuit board with slots therethrough through which the switches are disposed. The front-piece has a front portion extending outward from a front end and parallel to the bottom surface and has an annular armature formed thereon with a concentric pair of cross-hairs and a sensing coil of wire wound around the armature. A connecting cable of wires is connected to the sensing coil of wire and the switches. There is also a case top piece attached over the case bottom piece to form a hollow case which is tapered from back to front to give the case the feel of a mouse.

Abstract: In a pen plotter having plotting media supplied in the form of plotting media supply rolled around a hollow tube, this is a method and apparatus for automatically identifying the type of, and measuring the amount of, plotting media contained on the plotting media supply roll. A circular barcode strip is secured to the inner surface of the supply tube and is optically scanned to reveal the identity of the media contained on the supply roll. Said barcode strip's properties allow for the determination of the rotational velocity of the supply roll which, when used in conjunction with other known and easily derivable pieces of information, also allow for the precise calculation of the amount of media remaining on the roll. Knowing the identity of the media on the roll allows the plotter to handle the media in a manner consistent with its properties. Knowing the quantity of media remaining allows both media low and media out conditions to be determined and alarmed.

Abstract: This method and apparatus are suitable for inclusion in the "graphics circuit board" of a personal computer. The digital output of the computer is used to plot a series of "pixel pairs" which, taken together, closely approximate the desired path of a line to be drawn on a display device such as a color cathode-ray tube. The addresses and relative intensities of the pixels of each pair and of the series are computed so as to produce a line that is substantially free from the "jaggies" resulting from "aliasing" in prior-art apparatus. Computation of addresses relies upon both integer and floating-point numbers.

Abstract: In a cordless digitizing system wherein a cordless stylus having a manually operable button thereon transmits positional pulses to a tablet at a carrier frequency this invention is apparatus for transmitting status information about the button to the tablet. There is first status logic associated with the stylus for sensing the present status of the button and for encoding and transmitting the present status of the button as a binary 1 or 0 employing a first unique and recognizable sequence of carrier frequency cycles as a binary "1" and a second unique and recognizable sequence of carrier frequency cycles as a binary "0". Then, there is second status logic included in association with the tablet for recognizing the first unique and recognizable sequence of carrier frequency cycles to be a binary "1", for recognizing the second unique and recognizable sequence of carrier frequency cycles to be a binary "0", and for determining the present status of the button therefrom.

Abstract: In a pen plotter having a pen carriage exchangeably carrying a pen with a downward-facing plotting tip controlled in its movement over a plotting area by control logic and also having a multiple pen-holding rotating turret hub controlled by the control logic, this invention consists of cleaning apparatus for automatically cleaning the tip of a pen after pickup from the turret hub and prior to or just after use. There is a brush ring having upward-facing bristles concentrically carried by the turret hub and additional logic contained in the control logic for moving the pen carriage to the brush ring to place the plotting tip within the bristles prior to or just after plotting with the plotting tip and for rotating the turret hub and the brush ring in combination when the plotting tip is within the bristles whereby to clean the plotting tip with the bristles. The brush ring can be rotated bi-directionally for better cleaning if desired.

Abstract: In a cordless, electro-magnetic digitizing system having a drive circuit outputting a square wave drive signal of known initial polarity to a transducer coil in a cursor to oscillate the transducer coil and cause a magnetic field output therefrom which is detected in an associated tablet, a method of operation and associated apparatus for determining the phase of a response signal induced by the magnetic field from the response signal itself.

Abstract: A hand-operated optical scanning system which can be used to scan a large document in multiple passes. There is a digitizing tablet containing position-sensing circuitry for outputting a signal indicating the position of a sensing coil in an x-y coordinate system associated with a working surface of the digitizing tablet as well as a buffer memory for receiving pixelized data associated with optical scanning of a document. A hand scanner for scanning the document comprises, a case having a longitudinal axis, guide rollers for allowing movement of the case only substantially along the longitudinal axis, a read bar centered on the longitudinal axis and perpendicular thereto for optically scanning a one-dimensional line of pixels and for outputting a signal reflecting an instantaneous scanned image, and a sensing coil carried by the case centered on the longitudinal axis at a pre-established distance from the read bar for being positionally sensed by the position-sensing circuitry of the digitizing tablet.

Abstract: A three-piece, all-plastic idler pulley assembly. There is a first unitary bell end portion having a first circular, inward-facing face with a concentrically-disposed, cylindrical shaft extending outward therefrom and perpendicular thereto. The cylindrical shaft has a concentric longitudinal bore therein. There is also a second unitary bell end portion having a second circular, inward-facing face with a concentrically-disposed, cylindrical projection extending outward therefrom and perpendicular thereto. The cylindrical projection is disposed within the longitudinal bore of the cylindrical shaft whereby the second circular, inward-facing, vertical face is disposed at the end of the cylindrical shaft perpendicular to the first inward-facing face and the second bell end portion is connected to the first bell end portion and spaced therefrom. A plastic cylindrical hub is rotatingly mounted on the cylindrical shaft between the first inward-facing face and the second inward-facing face.

Abstract: In a media transporter which positions media, a method and apparatus is provided for positioning the media for accurate alignment. The method includes the steps of sensing a spatial pattern of densities in the media along a scanned strip, saving the spatial pattern of densities during the initial pass to create a path map from the start position to an end point, comparing subsequently sensed spatial patterns of densities to the path map, and following the path map to repeatedly and accurately position the media at any point along the scanned path. The spatial pattern of densities in the media is sensed by shining a light through the media and sensing the transmitted light intensity.

Abstract: In a push-to-release latch connected to a door/lid revolving about an axis of rotation of a cabinet between open, closed and unlatched, and closed and latched positions wherein the closed and unlatched and closed and latched positions are rotationally displaced from one another, apparatus for determining the status of the latch without sensing the latch. A reflector is carried by the door/lid or the cabinet and a non-contacting optical sensor carried by the other for directing a beam of light from an emitter, for receiving the beam of light as reflected by the reflector, and for outputting an electrical signal at an output thereof as a function of reflected light. The reflector and the non-contacting optical sensor are positioned such that the beam of light strikes the reflector to be reflected thereby when the door/lid is in a closed and latched position and the beam of light does not strike the reflector to be reflected thereby when the door/lid is in a closed and unlatched position.

Abstract: In a pen plotter having a plotting head carrying one half of a pen exchanging mechanism including a holding plate pivotally attached to a plotting head for pivotal movement to raise and lower a pen gripped therein and carried thereby a spring-biased gripping finger pivotally carried by the holding plate for releasably holding a pen, this is a dual-function sensing apparatus for providing a single output signal indicating pen presence and pen up/down position. There is an optical sensor comprising a light source and a light detector separated from the light source by a space and having a sensing surface upon which a beam of light impinges and wherein the level of signal output is a function of the amount of light impinging on the sensing surface.