Abstract: The invention relates to an apparatus for detecting sheet misfeed from a multi-tray sheet feeder. The thickness of the first sheet fed from each tray is detected by a common sensor and a thickness value is placed in memory for that tray. Each sheet subsequently fed from the same tray is detected by the common sensor and the thickness value sensed is compared with the thickness value in memory for that tray. If the values match, then only one sheet has been fed from the tray. If the thickness value is more that the thickness value in memory for that tray, then that indicates that more than one sheet has left the tray and the system is shut down to enable an operator to correct the situation. When a tray is reloaded, the thickness value in memory for the sheets previously loaded in the tray is erased and the first sheet fed from the reloaded tray is sensed and a thickness value for that sheet is placed in memory for the reloaded tray.

Abstract: A single piezoelectric transducer is used to drive an array of drop-on-demand ink jet ejectors. This is accomplished by utilizing a plurality of electrodes which divide the piezoelectric transducer into discrete, deformable sections, each section corresponding to an ejector.

Abstract: A coincidence ink jet principle is disclosed wherein each ink jet has two inlet passages communicated to an outlet orifice. Each inlet passage is communicated to a respective transducer chamber. The fluid displacement and fluid velocity effected by a pressure pulse generated by each transducer chamber in a respective inlet passage is insufficient to express a droplet from the orifice. However, the combined fluid displacement and fluid velocity, which is the result of the pressure pulses generated by the transducers being coincident at the orifice, will result in a droplet being expressed from the orifice.In one system disclosed utilizing the above described principle, each inlet passage of a jet is communicated to a respective transducer and each transducer is connected to a respective electronic driver. In this system, the number of electronic drivers and transducer chambers are substantially less than the number of ink jets. These transducer chambers are time shared for expressing an ink droplet.

Abstract: The output beam from a laser scans an input document and the signal reflected therefrom, corresponding to information on the document, is detected and amplified in a first amplifier and converted to an electrical signal. The laser beam is also sampled prior to scanning the document, the beam being detected and converted to an electrical signal which is then amplified in a second amplifier. The outputs of the first and second amplifiers are coupled to a gain control device. The gain versus control voltage characteristic of the device is selected such that the voltage from the second amplifier controls the voltage output from the device whereby noise present in the output laser beam which modulates the output signal from the first amplifier is substantially eliminated.

Abstract: Parallel connections are provided from high voltage power supplies of opposite polarities through separate light dependent resistors to an electrical load. Separate light emitting diodes are associated with each of the light dependent resistors and are driven by a differential amplifier having one reference input and another input responsive to load current or voltage. The load current or voltage is regulated or programmed through a relatively low voltage power supply and a programmed or regulated amplifier which manipulates the illuminating effect of the light emitting diodes to vary the resistance of the light dependent resistors in a prescribed manner. This manipulation of the resistances imposed in the parallel power leads produces an alternating current across the load. The reference input to the differential amplifier is preferably adjustable.

Abstract: An impact printer is provided with an easy load print wheel mechanism. A print wheel cartridge containing a print wheel therein, is inserted into position without disturbing the position of a print wheel drive motor, a ribbon cartridge or hammer mechanism. The easy load mechanism automatically grabs the print wheel cartridge to swing the cartridge into a print wheel loaded position whereby the print wheel within the cartridge is automatically coupled to the print wheel drive motor shaft.

Abstract: A liquid developer is presented to a charge pattern on a photoconductor surface as an evenly distributed array of droplets passing tangentially to it. The droplets emanate from a series of jets and are spread into an even pattern electromagnetically. The charge pattern is developed by the droplet which it draws to the photoconductor surface.

Abstract: A mapping arrangement for memory overlay wherein the address coordinates are referenced to a main serial memory. This main memory is partitioned into pages of equal size. An accelerator memory is concurrently loaded with a few pages representing a small portion of the main memory contents and is periodically overlayed with new memory contents on a page-at-a-time basis as the using system demands. During this overlay the fields of the accelerator memory are inscribed at corresponding main memory address coordinates together with code bits indicating whether certain memory fields go together and are therefore promoted as a single unit. The resulting effect is to cause an apparent increase in page size since more than one page is promoted as a consequence of a reference to a page not contained in the accelerator memory.

Abstract: A memory control processor adapted to expand a random access or accelerator memory by logical overlays which performs these overlays into memory fields (pages) on the basis of page usage history. To provide a quick reference to page use a chronological sequence is established by links rather than by reordering a stack. This link sequence is tied by very limited leads to the rest of the memory control processor and can therefore be updated during each memory access. In addition the memory control processor includes a task priority logic integrating various competing memory access requests with the overlay operations. To achieve the various transfer modes in the quickest time the memory control processor is organized around a wide control memory storing the task servicing sequences. The width of the control memory and the associated task logic allow general purpose microprogrammable direct memory access which may further be utilized in multiplexed fashion to accommodate various concurrent tasks.

Abstract: An electro-optic modulator/deflector for use with a light beam comprising at least two wavelengths of light including an electro-optical material and an electrode pattern adjacent a first surface of said material arranged in response to a voltage supply to provide an electric field in the material to influence the deflection of the light beam at the moment of total internal reflection at the first surface. The light beam is divided into its constituent wavelengths which are directed to different parts of the first surface, the electrode pattern comprising interdigitated electrodes arranged so as to modulate separately the different wavelengths by predetermined respective amounts.

Abstract: An impact printer is provided with an easy load print wheel mechanism. A print wheel cartridge, containing a print wheel therein, is inserted into a print wheel loaded position and removed therefrom without disturbing the position of a print wheel drive motor or ribbon cartridge. The print wheel drive motor shaft is automatically coupled to the print wheel within the cartridge upon insertion of the cartridge into print wheel loaded position.

Abstract: A magnetic bubble element which is useful as an image information processing element. A thin film made of a magnetic bubble forming material has a plurality of wedge-formed patterns made of a non-magnetostriction soft magnetic thin film is formed on the upper surface of the thin film 16. A conductor grating comprising two undulating conductor patterns are provided each cycle of the undulation in both conductor patterns defining a wider pitch and a narrower pitch, each of the wedge-formed patterns being disposed over the corresponding part of one of the two conductor patterns defining the narrower pitch in a manner such that the apex portion and the bottom portion of each wedge shaped pattern extend into the parts forming the wider pitch.

Abstract: An improved analog meter is provided having no moving parts. This meter comprises a tapered resistor device having a tapered, electrically resistive element which develops a non-uniform temperature profile on electrical energization and a heat sensitive element operatively associated with the tapered resistive element. The heat sensitive medium employed is a reversible medium which either undergoes a change in color or contrast when heated to an appropriate temperature and when viewed under appropriate illumination. A method of metering employing this device is also disclosed.

Abstract: An apparatus for substantially eliminating the effects of a nonsinusoidal current from a reactive or nonlinear load as applied to a resistive load requiring an input current that appears to be sinusoidal. If the amplitude of the current source as applied to the resistive load can be controlled through a switching regulator by matching a sine wave reference signal with current inputed from the current source then said input current may be forced into a sinusoidal mode that is in phase with the voltage thereof. Accordingly, with the input current in a phased sinusoidal condition, harmonic elimination and power factor correction may be afforded to the inputed power relative to the resistive load.

Abstract: A tapered resistor device which includes generally a tapered resistive film comprising a semiconducting material or other suitable material with a negative temperature coefficient of resistivity is provided. It is apparent with reference to the curves which show the variation of .DELTA.E that large energy savings are possible at the narrow end of the taper with relatively small concomitant degradation in the temperature profile of the region of interest. It is therefore seen that employing a material with a negative temperature coefficient of resistivity provides an improvement in reducing power usage according to the principles of the instant invention.

Abstract: An autonomous processor for displaying on a video tube both text characters and facsimile data. To conserve memory space the facsimile data is stored in compressed form and is decompressed or unfolded in synchronism with the vertical and horizontal deflections in the video tube. Similarly the text characters are stored in coded form, together with interspaced commands, both inscribed in a list memory. Each character code in the list then selects an appropriate dot matrix from a font memory which also contains displacement data. Selected lines of the font dot matrices are then addressed by row coordinates to form a horizontal video signal, which is accumulated in a ping pong buffer concurrently unloading into a video register. This same video register merges the facsimile data which is concurrently unfolded.

Abstract: A diode laser having an active region which has a section in the shape of a closed loop or ring, with the path length of the loop or ring causing a light wave traveling completely around the loop or ring section from a coupler section of the active region to undergo a phase shift of 180.degree. relative to its starting phase whereby the two waves interfere destructively, and thus provide optical feedback.

Abstract: A semiconductor device which utilizes interferometric principles and electrical control to provide either light reflection or light transmission or partial light reflection/transmission. In a preferred embodiment, the device includes an input waveguide which divides into branch waveguides, with the branch waveguides being reunited at an output waveguide. When the optical path lengths of the branched waveguides varies by an integer multiple of the light wavelength in the guides, the light waves interfere constructively at the output waveguide causing light to be transmitted into the output waveguide. When the light wave in one branch waveguide undergoes a single pass phase shift of 180.degree. relative to the light wave in the other branch waveguide, the light waves interfere at the output waveguide and are caused to return to the input waveguide through the branch waveguides. The returning light wave in the one branch waveguide once again experiences a single pass 180.degree.

Abstract: There is disclosed a light system for projection of images onto a visual read out surface such as a screen or photo receptor recording device such as a xerographic drum. The projection system employs a nonpoint light source which forms a light beam of nonuniform intensity. The light beam is passed through a conical light pipe with a high degree of internal reflection which diffuses the light beam, thereby reducing the nonuniformity of the light beam and also collimates the light beam by internal reflections. The collimated light beam is then modulated with imaging information and is focused onto a visual readout surface such as a screen or a recording device surface.

Abstract: A distributed function processing system utilizing a conventional microprocessor operated as a text processor in combination with a plurality of other autonomous processing devices arranged to operate in a coherent processing system. One of the autonomous processors which is a memory control processor serves to periodically overlay a random access accelerator memory with the contents of a main memory system and concurrently resolves conflicts among various other autonomous memory service requests. This processor, therefore, accommodates the data rates of the main memory. The other processor is a display processor which generates signals to a video display system to provide a visual interface to the user and is therefore tied to the video rate. Accordingly, the processing burden is distributed within processors entailing differing rates operating autonomously.