Abstract: A piezoelectric DOD printing system including a piezoelectric-based print engine, a micro pump, an ink line, a vacuum sensor, and control circuitry. The micro pump delivers ink from a cartridge reservoir to the print engine. The ink line fluidly connects an outlet of the micro pump with an inlet of the print engine. The vacuum sensor is fluidly connected to the ink line. The control circuitry is electrically coupled to the vacuum sensor and programmed to control operation of the print engine and the micro pump. The control circuitry activates and deactivates the micro pump based upon information from the vacuum sensor.

Abstract: A piezoelectric DOD printing system including a piezoelectric-based print engine, a micro pump, an ink line, a vacuum sensor, and control circuitry. The micro pump delivers ink from a cartridge reservoir to the print engine. The ink line fluidly connects an outlet of the micro pump with an inlet of the print engine. The vacuum sensor is fluidly connected to the ink line. The control circuitry is electrically coupled to the vacuum sensor and programmed to control operation of the print engine and the micro pump. The control circuitry activates and deactivates the micro pump based upon information from the vacuum sensor.

Abstract: A sensor device including a base, first and second proximity sensors mounted to the base at a pre-determined distance from one another, and circuitry programmed to determine presence and speed of an article passing by the sensor device based upon signaled information from the proximity sensors.

Abstract: Obstruction detector apparatus operatively coupled to an automatic electric door operator compares the time span of transmission and receipt of reflected echoes of ultrasonic energy within a door passageway obstruction zone with predetermined time spans in order to prevent door closure under conditions indicating passageway obstruction or system malfunction. Signal generators provide timing signals respectively representative of the anticipated time span of reflected echoes from locations in front of, and beyond, the door jamb opposite the ultrasonic transmitter and receiver transducers for comparison by a relay controller with the time of generation of a signal representing a reflected echo at the transducer receiver, the relay controller appropriately actuating a door operator relay in response to such comparison.

Abstract: In a control system for a bidirectional printer capable of printing at different speeds on different lines and in which the actual velocity of the print carriage is compared with a desired velocity profile to generate an error count, the error count is measured and averaged out for each direction and speed of carriage movement to compensate for the effect of changes in the printer system dynamics such as aging, wear, debris buildup, etc.

Abstract: A microprocessor controlled printer includes a forms feed assembly, a dot matrix print assembly, a ribbon drive assembly and a number of emitter assemblies associated with the foregoing to provide positional information during operation of the printer which prints on a line-by-line basis. During the printing of characters, such as Kanji characters, extremely accurate control of dot placement is required. In order to achieve a balance between the operating cycle times of the microprocessor and the forms feed assembly, the microprocessor analyzes emitter pulses in two stages. One stage involves use of relatively low frequency emitter pulses for start-up, normal speed, and high speed operations. Another stage involves use of an additional emitter track that produces high frequency pulses utilized by the microprocessor during stopping conditions to achieve greater precision in final positioning of the forms.