Abstract: Apparatus and method for testing and determining the operating status of a plurality of ink-ejecting nozzles in a thermal ink jet array. An electrically conductive plate is placed adjacent the ink-ejecting orifices in a test position. An ink droplet appearing from an orifice will, for some brief moment, be in contact with both the orifice plate and the electrically conductive plate. The droplet completes a circuit with a conduction detector and allows current to flow thereby indicating an operative nozzle.

Abstract: An orifice plate for an ink jet printhead wherein a plurality of elongated isolator slots are adjacent the orifices and in fluid communication therewith, so as to prevent cross-talk between adjacent orifices.

Abstract: Cleaning and priming of ink-ejecting nozzles is achieved by engaging the nozzles with an elastomeric suction cup as the printhead moves to the beginning or ending of a print line. The suction cup contains an inner cup of foam which wipes off any residual ink droplets. The cup assembly is connected to a vacuum pump for drawing ink out of the nozzles. The assembly is mounted on a four-bar linkage which, as it rotates, lifts the cup assembly to engage the nozzles in the printhead.

Abstract: A method of providing electrical connections to a flexible circuit member having electrical contact pads of solderable material on one side. The contact pads and the flexible circuit are pierced with contact pins. Solder is caused to flow along the contact pins through the openings in the flexible circuit from the side opposite to that on which the contacts are disposed.

Abstract: A cable drive system is provided in which a fixedly mounted reversible motor imparts translational motion to a plurality of pairs of elements such as the right and left pairs of paper moving tractors in a high-speed printer. By means of a continuous cable loop routed around passive rotational elements, each element of a pair of elements, each of which is rigidly attached to the cable, can be translated the same distance in the same direction as the other while the relative alignment of one element with respect to the other element is maintained. Means for selectively translating one pair of elements independently or a plurality of pairs of elements simultaneously while maintaining the distance between the pairs are provided.

Abstract: In a standard residue class analog-to-digital converter, pseudo-random noise is introduced at first or subsequent approximations of an analog input signal by the local digital-to-analog converter.

Abstract: A passivation layer in a thermal ink jet printhead is formed or "grown" by a reaction between the materials of the ink jet structure to be protected and an element which will form a chemically inert, electrically insulating, thermally conductive compound. The resistor structure may be of tantalum or tantalum nitride and the electrical conductors therefor may be of aluminum. By subjecting this resistor-conductor structure to a reactive oxide atmosphere, the exposed surfaces of both are anodized so that a surface film of aluminum oxide is formed on the aluminum conductor and a surface film of tantalum pentoxide or tantalum oxynitride is formed on the resistor structure.

Abstract: An orifice plate is provided of an electroformed material which incorporates an integral ink distribution manifold and integral hydraulic separators between orifices. The general approach to the method of making the orifice plate is to first construct a two-part mandrel made up of a "hard" mandrel which can be reused many times and a "soft" mandrel which is renewed each time the mandrel is used. Typically, the surface of the "hard" mandrel is configured by mask and etch techniques, or by mask and electroplate techniques to define the ink distribution manifold and the hydraulic separators, while the "soft" mandrel is configured by mask and develop techniques to define the orifices and edges between orifice plates. Upon completion of the mandrel, its surface is electroplated with a relatively uniform thickness of metal, and the newly electroplated surface having the orifice plates patterned therein is separated from the mandrel.

Abstract: A protective passivation structure is provided for a thermal ink jet printing head which employs a resistive heating element formed of phosphorus-diffused silicon. The passivation structure includes a layer of silicon nitride over the heating element with a layer of silicon carbide over the silicon nitride layer. The nitride exhibits good adhesion to the underlying silicon as well as good thermal conductivity. The carbide has exceptionally good wear and hardness qualities against ink bubble cavitation as well as adhering well to the nitride.

Abstract: A circuit for varying the power supplied from a D.C. power supply to a moderate to high powered load such as a motor is disclosed. Trapezoidal voltage and current waveforms are used approaching the maximum load power delivery available from sine wave drives and the minimum dissipation in the driver circuitry available with square wave drives, while at the same time minimizing the generation of undesirable electromagnetic interference (EMI).

Abstract: A mount is provided for electrolytic capacitors, the mount being in the form of a ring having an internal shoulder portion. On the opposite end of the mount from the end on which the shoulder portion is located is a groove containing a compressible O-ring. When the capacitor is inserted in the mount with its terminals extending downwardly to the surface of a circuit board, the top edge of the capacitor can rest on the shoulder of the ring mount. Screws are inserted from the opposite side of the circuit board and engage the terminals. Upon being tightened, the capacitor can is drawn downwards bringing the end of the capacitor can into firm engagement with the ring mount and causing it to compress the O-ring so as to provide a seal between the O-ring and the surface of the circuit board.

Abstract: A module for dust-free containment of rotating data storage media such as disc packs, both in and out of the drive, including top and bottom covers, sliding door access for read/write heads and filtered air, a carrying handle coupled to the media hub for carrying the module and for locking the media in a fixed position within the module while being transported, and a removable chuck plate cover for covering a magnetic chuck plate and for locking the media in a fixed position within the module while being stored.

Abstract: The present invention provides a real-time fault-tolerant hardware error correction device which is typically implemented as a data transfer circuit between a disc memory and a processing unit. It operates in two modes: as an encoding system and error detector on a disc write, and as a decoding system and error corrector on a disc read. In its first mode, each block of data from the processing unit is encoded with an error syndrome as it is transmitted to the disc memory. Two identical linear feedback shift registers (LFSR's) are used for error detection purposes. In its second mode, the same two LFSR's are implemented with a buffer memory to achieve real-time error correction. Data flow to the LFSR's from the disc memory is alternated block-by-block, one block being received by one LFSR and the succeeding block being received by the other LFSR. At the same time that data is channeled to a particular LFSR, it is channeled synchronously to the buffer memory.

Abstract: An apparatus amplifies a signal in two different modes. The apparatus amplifies the signal in a linear mode when the voltage of the signal is much less than the voltage of the power source, and in a switching mode when the signal is at other voltages.

Abstract: Data representations are translated on a rotating disc utilizing multiple transducers at different radial positions. The disc is logically formatted into selected concentric bands. Within each band data representations are translated alternately in a repetitive sequence among a selected number of transducers characteristic of the particular band. By appropriately selecting band format parameters and increasing the characteristic number of transducers as a function of decreasing band radial position the track data density may be maintained within selected limits.

Abstract: An improved laser pumping system is provided which utilizes optic fibers configured in a fan-in arrangement and an array of light emitting diodes or diode lasers to which the optic fibers are connected for concentrating light energy on a lasing medium. The improvement is an increase of the amount of light energy that can be applied to the laser within a fixed volume.

Abstract: Method of and apparatus for operating an image display system using a hybrid field effect liquid crystal light valve of the type wherein the molecules of the nematic liquid crystal layer are helically twisted through an acute angle. A polarized projection beam is oriented with its polarization direction within the acute twist angle and applied to a reflective face of the light valve. A writing light input image is applied to a photoresponsive opposite face in order to modulate the reflected projection beam. An electric field applied across the light valve is adjusted between two levels to produce either a simultaneous display of multicolor symbology and achromatic (black-white) gray scale images or a separate display of either one of them.

Abstract: The specification discloses a process for forming a graded index waveguide structure by first providing a substrate of a first selected optical material having a chosen index of refraction. Next, a patterned layer of a second optical material is formed on one surface of the substrate or, optionally, within selected cavities formed in the substrate. This second optical material has a refractive index which is larger than the refractive index of the substrate. The patterned layer of the second optical material is formed in a predetermined geometry and to a predetermined thickness. Then, a layer of a third selected optical material is formed on the patterned layer of the second optical material and on the substrate surface to a predetermined thickness. This third optical material has a refractive index which is substantially the same as the refractive index of the substrate.

Abstract: A floating gate tunneling metal oxide semiconductor (FATMOS) transistor is formed in a well region on a semiconductive substrate of a conductivity type opposite to that of the well region, so that charging and discharging of the FATMOS floating gate is accomplished by controlling the potential of the well region. As a result, in an electrically erasable programmable read-only memory, each memory cell requires only one FATMOS transistor, the need for an additional control transistor having been eliminated. Selection of individual memory cells is enhanced by providing a floating gate which only partially overlies the FATMOS transistor channel, so that the overlying FATMOS control electrode performs an "and" gate function independently of the floating gate.

Abstract: A meander channel charge couple device having a pair of parallel colinear elongate electrodes extending longitudinally along the length of the register disposed over a meander channel and formed in the same conductive layer so that they both reside at the same height above the semiconductor substrate, thereby providing a symmetrical surface potential distribution. Charge transfer instabilities beneath a gap separating the electrodes are eliminated by providing an additional set of electrodes, each extending transversely to the meander channel and to the first pair of parallel electrodes and spanning the gap. Contact is made by each of the longitudinal electrode pairs to alternate ones of the transverse electrodes and a two-phase clock system is applied to the longitudinal electrode pair.