Abstract: A method of detecting a fault within a micro electro-mechanical device in the form of an ink ejection nozzle having an actuating arm that moves an ink displacing paddle when heat inducing electric current is passed through the actuating arm and having a movement sensor associated with the actuating arm. The method comprises the steps of passing at least one current pulse having a predetermined duration through the actuating arm and detecting for a predetermined level of movement of the actuating arm. If a fault is detected to exist, as indicated by an insufficient level of movement of the actuating arm, at least one further current pulse having an energy level greater than the fault detecting pulse may be passed through the actuating arm in an attempt to clear the fault.

Abstract: Ink jet printers used for printing large characters employ a separate solenoid valve for each drop stream which forms part of a printhead matrix. By optimizing the frequency response of the nozzle/valve sub system (primarily the connecting tubing), higher operating frequencies can be obtained. It has been found that a ratio of six to one between subsystem resonant frequency and operating frequency provides greatly improved printing.

Abstract: An improved method and apparatus for controlling an electrostatic plotter is disclosed which results in an increased speed for the plotter. This speed is achieved by dividing the picture to be printed into frames and processing the individual frames in parallel with separate controllers for each frame. The styli on the electrostatic printer's head will accordingly be divided into the separate frames. The raster data produced by each of the controllers is combined to form the entire picture and is forwarded to the plotter.

Abstract: A method for preformatting each track of an optical disk with spaced header patterns using a plurality of overlapping, individually modulated writing laser beams arranged in a line perpendicular to the track. All of the writing laser beams are derived from a single multi-line laser so as to provide high positioning stability, and adjacent beams are chosen to have different wavelengths in order to prevent the deleterious effects of coherent interference between the overlapping beams. A specific header pattern is provided on a single pass by turning on different ones of the writing beams during specific time periods as each header recording area is traversed. A laser read-after-write beam is additionally provided to permit immediate verification of the recorded header pattern.