Abstract: A word processor system comprising a typewriter, a data storage unit, a tab stop register for storing signals representative of tab stops set on the typewriter and means for controlling the tab stop register to keep it aligned with the typewriter carrier during the course of typing including backspacing, carrier return and tabbing actions. Additional means responsive to tab command and tab stop signals is provided for recording a tab action in the data storage unit as a succession of encoded space signals equal to the number of typing positions to the next tab stop from the carrier position at the instant of the tab command.

Abstract: An electromagnetic actuator is disclosed having a magnetic circuit which provides a plurality of annular, concentrically located air gaps and a plurality of annular actuator forms which are positioned in the air gaps. A winding is mounted on each of the forms and each winding is adapted when electrically energized to establish a field which reacts with a field of the magnetic circuit and causes rectilinear motion of the form in an axial direction. A single magnetic circuit is thereby provided for a plurality of actuating forms and advantageously reduces the iron requirements of the actuator.

Abstract: A microprocessor system includes a microprocessor, a memory, and one or more direct memory access controllers, all connected to a common system bus which includes a system address bus and a system data bus. At least one of the direct memory access controllers is shared by a plurality of subsystem device controllers which may control peripheral devices having diverse characteristics. The microprocessor is limited in its instruction repertoire and may control peripheral devices only by means of an input and an output instruction. The shared direct memory access controller includes no circuitry which is specifically for controlling only a single type of peripheral device, the device dependent logic being located in subsystem device controllers. Data transfers may take place directly between the memory and, through the shared direct memory access controller, any selected one of the peripheral devices.

Abstract: Apparatus including means for fluidically supporting and guiding a moving, cylindrically formed thin metal belt used in the transport of magnetic particles. Magnet pole pieces disposed adjacent the surface of the belt accommodate formation thereon of a non-translating, rotating bead of dry magnetic ink particles in the application of a uniform ink coating over the belt suitable for printing. The belt is held in substantially fluid tight relation along its opposed edges on bearing means affording rotation of the belt about a fixed, axially extending mandrel including fluid supply cavities and a magnet support cavity. The fluid supply cavities terminate in radially presented recessed orifices for discharging a fluid into a relatively close space provided between the mandrel and the belt, to the side of the latter opposite the surface on which the ink bead is formed by a magnet disposed within the magnet cavity.

Abstract: A multi-jet ink printer comprises a drum having rows of pointed jet formers, or prongs, mounted about its outside surface. The drum is successively rotated such that the tips of the prongs are dipped into a reservoir of ink and thereafter pointed toward a recording carrier, such as paper. When the prongs are directed toward the carrier, an electrostatic field is established between the drum and electrodes located on the opposite side of the carrier. The ink is thereby caused to leave the sharp points and form ink jets composed of very small droplets of ink. The ink is thereby deposited on the carrier. There is an electrode located opposite each prong which is selectively energized to produce dots on the carrier when the prong is in selected positions relative to the carrier. In this respect, the drum is moved axially (horizontally) to scan rows on the carrier, and the carrier is moved longitudinally (vertically) to scan vertically on the carrier.

Abstract: A phase detector comprising three bistable flops and a NAND gate interconnected to respond to a data input pulse stream and a controlled square wave clock pulse stream to provide, in response to each data pulse, a reference pulse having a width equal to one-half the clock pulse period and a variable pulse having a nominal width equal to that of the reference pulse and a proportionately greater or lesser width according to the direction and amount of displacement of the data pulse from the center of the clock period in which it occurs.

Abstract: An on line high speed printer is described in which any of a plurality of non-printable characters can be printed as a preselected printable mating character. The printer control system includes a first circuit for detecting the presence of a selected one or group of non-printable characters in a line of data to be printed. A second circuit detects when a preselected printable character on the type member of the printer occupies a print position corresponding to the columnar print position of the detected non-printable character. The second circuit operates when the above condition occurs and actuates the printer and causes preselected printable characters to be printed in the columnar position of the detected non-printable character.