Abstract: An optically readable record for storing encoded information comprises (1) a recording medium, (2) a self-clocking data code for encoding the information, with this data code being composed of glyphs that are written in a two dimensional code field on the recording medium on centers that are spatially distributed in nominal accordance with a predetermined spatial formatting rule, where the glyphs are defined by respective symbols that are selected from a finite set of optically discriminable symbols to encode the information, and (3) a self-clocking synchronization code pattern that is written on the recording medium to fully frame at least a portion of the data code, with this the synchronization code pattern defining multiple paths of self-clocking glyphs for reaching any given glyph of synchronization code pattern from any other glyph thereof.

Abstract: A device for moving an object, such as a sheet of paper or other substrate, includes a base element, a drive mechanism to move the base element in first and second directions, such as by vibration, and a plurality of flexible ratchets fixedly secured to the base element. As the base element vibrates, the ratchets advance the sheet of paper in a direction perpendicular to the direction of vibration of the base element. Pluralities of base elements and drive mechanisms can be provided to direct movement of the substrate in various directions.

Abstract: A self-clocking glyph code is composed of data glyphs which encode logically ordered data values, together with one or more multi-glyph synchronization code patterns. Each of the synchronization code patterns is distinguishable from the data glyphs, but the synchronization code pattern or patterns provide an explicit spatial reference for the data glyphs. To this end, the glyphs of the synchronization code pattern or patterns are written on the recording medium in accordance with the same spatial formatting rule as the data glyphs, plus at least one additional formatting rule that establishes a predetermined geometric relationship between the glyphs of the synchronization code pattern or patterns and corresponding ones of the spatially formatted data glyphs, such that the logical order of at least a significant number (>>1) of the data glyphs is inferable from the synchronization code pattern or patterns.

Abstract: The Ionographic Beam Positioning And Crosstalk Correction Using Grey Levels is a method and apparatus which solves the problem of poor density and definition of an image formed by an ion current (20) projected from an ionographic print head (10), caused by electric field crosstalk between adjacent modulation electrodes (22) in the head (10). By applying a partial modulation voltage (V.sub.M ') to the adjacent modulation electrodes (22), the density of an individual pixel charge is increased and the pixel charge is "addressed" or deflected to a position on a receptor surface (26) more precise than the pitch dimension between modulation electrodes (22). A data processor (46) intercepts printing driver commands (44) and constructs therefrom values of partial modulation voltage (V.sub.M ') by means of an algorithm making deliberate use of the crosstalk phenomenon. The algorithm is pre-defined with respect to image-dependent modulation voltage states and implemented as programmed software or firmware.

Abstract: To correct for blooming artifacts in an ionographic imaging device, a summation of the effects of previously deposited charge is made prior to depositing ions to form the image, to determine the likely amount of displacement of any ion due to a previously deposited charge. A comparison of the displaced pixel position, with the desired image is made to determine where the ions will fall. If the ions are predicted to fall within an area in which ion deposition is desired, ions are allowed to pass to the imaging surface. If the comparison of the displaced pixel position with the desired image is made and predicts that ions will fall outside of an area in which charge is desired, ions are prevented from passing to the image surface.

Abstract: A capacitive tactile sensor array is formed of capacitive plates formed on a dielectric substrate, on which large area electronics is also deposited. A conductive film is spaced from the capacitive plates, to form the other plates of the sensor capacitors. This conductive film may be grounded. The large area electronics includes a circuit that provides outputs corresponding to the pressure applied to each of the sensor capacitors. A method is also disclosed for controlling the circuit to provide an output corresponding to the pressure applied to the conductive film.

Abstract: The present invention is a method and apparatus which solves the problem of rapidly calibrating to a uniform value, the ion current (i) associated with each modulation electrode (50) of a print array (40) in an ionographic printing head (10). The calibration data may then be used during printing to produce high quality images of uniform density. The present invention employs a calibration array (30) positioned to sense the ion current (i) associated with each opposing modulation electrode (50) as a voltage (V(i)) across a calibration electrode (70) load resistance (R). When the instantaneous value of ion current (i) and the desired calibrated ion current (i.sub.F) differ when presented to a comparator, a feedback circuit (62) feeds back an error voltage (V.sub.INT) to a driver (100) coupled to the modulation electrode (50). The modulation voltage (Vm(i)) and the error voltage (V.sub.

Abstract: Weighted and unweighted convolution filtering processes are provided for decoding bitmap image space representations of self-clocking glyph shape codes and for tracking the number and locations of the ambiquities or "errors" that are encountered during the decoding. This error detection may be linked to or compared against the error statistics from an alternative decoding process, such as the binary image processing techniques that are described herein to increase the reliability of the decoding that is obtained.

Abstract: The In Situ Ionographic Uniformity Correction is a method and apparatus which solves the problem of non-uniform density of ion current projected from an ionographic print head (10) caused chiefly by variations in the dimensions of the modulation channel (24). During calibration, the present invention senses ion current (20) using a simplified ion sensor (36) which has an electrode (32), very large in proportion to the width of several modulation electrode (22). Groups (60), (61) of modulation electrodes (22) are electronically addressed in steps of one modulation electrode (22), each, across the width of the print array (16). To prevent cross-talk from rendering the sensed ion current (20) values unusable, the modulation voltage (Vm(i)) is adjusted by a feedback circuit (42) to achieve a fixed value of ion current (20) for each group (60), (61). Values of this modulation voltage (Vm)I)) are stored in an electronic data file (44).

Abstract: A method for the situ measuring of a sample of a porous material having a gaseous fluid and fine granular material located within its pores and, in particular, for determining the concentration of the fine granular material within the sample. The method includes the steps of generating a first acoustic wave signal of known amplitude and phase velocity, directing the first acoustic wave signal through the sample, receiving a second acoustic wave signal representing the first acoustic wave having passed through the sample, and determining the concentration of the fine granular material in the sample from the changes between the first acoustic wave signal and the second acoustic wave signal.

Abstract: A method and apparatus for transporting electrically charged particles suspended in a fluid, such as ions or the like, through said fluid, in a transport direction by means of a traveling electrostatic surface wave. The apparatus includes an array of transport electrodes to which a source of AC multi-phase potential is applied to create a stable and controllable particle transport system in which the charged particles have a compound motion comprising a generally cyclical movement and drift movement through the fluid, in the transport direction. The locus of charged particle movement is maintained above the surface of the electrode array.

Abstract: A heater for an ionographic marking apparatus including a housing, means for generating a supply of marking ions within the housing, means for transporting the marking ions through and out of the housing, and an array of modulation electrodes upon a substrate for controlling the transport of ions out of the housing, the modulation electrodes being spaced from one another by electrically insulating regions. The heater is associated with the array for raising the temperature of the electrically insulating regions so as to prevent the condensation of moisture thereon.

Abstract: A noncontacting method of measuring periodic surface heating is described. The perturbation of an externally generated acoustic wave is measured. The acoustic wave is generated in the air above a sample to be studied. The acoustic wave is directed onto the sample surface, coincident with a modulated light beam. Absorption of the light beam results in the periodic heating of the sample, at and near the sample surface. The air in contact with the sample surface is in turn heated, and produces a periodic phase shift in the reflected acoustic wave. This phase shift is detected and gives a direct measure of the periodic heating of the sample surface. An acoustic microscope may generate the acoustic wave. The sample is placed in water. An acoustic microscope lens produces an acoustic wave in the water, which focuses onto the sample surface, coincident with a modulated laser beam. The light beam is guided onto the sample using an optical fiber.