Abstract: A length mode drop on demand type ink jet print head includes a lower body portion formed of an active piezoelectric material and an upper body formed from an inactive material. The lower body portion, which includes a plurality of longitudinally extending projections, is poled in a first direction generally orthogonal to both its longitudinal and vertical axes. The upper body portion also includes a plurality of longitudinally extending projections. The lower and upper body portions are mated such that the lower and upper body projections are spaced interdigitally with each other. By mating the lower and upper body portions in this manner, a plurality of ink-carrying channels are formed. The ink jet print head further includes a controller for selectively applying an electric field across each of the lower body projections in the poling direction.

Abstract: An ink-jet type printer having a self-contained, unitary print-head and ink-supply cartridge which can be readily inserted or removed from the printer without requiring disconnection of or user-exposure to any part of the ink reservoir or ink delivery system. The large-capacity ink reservoir in the cartridge is separate from the ink delivery system and connected thereto by flexible hoses which allow the print-head to be moved independently from the ink supply. A drive gear for the print-head motion system, enclosed in the print-head and ink supply cartridge is partially exposed such that it engages a motor disposed within the printer housing when the cartridge is inserted into the printer housing. An elongated shutter mechanism in the cartridge opens during printing to expose the print-head to the printing surface. When the ink reservoir is exhausted, the cartridge is removed from the printer housing in a single motion.

Abstract: The thermal printhead of a printing terminal requires a controlled voltage to insure uniformity of the print copy. Printhead temperature is sensed by a voltage generating diode on the printhead itself. This feedback voltage is used to control the reference voltage of a switching regulator power supply which in turn provides power to the thermal printhead. The switching regulator comprises an efficient means of providing a controlled voltage to the thermal printhead.

Abstract: A control system moves an inductively controlled multi-phase motor in a forward or reverse direction. The motion may be in steps or it may be a continuous rotation. A microprocessor under the control of a ROM operates through an integrated input/out device to provide control signals for the motor.In the step mode of operation, a high current level is induced in the next motor phase so as to accelerate the motor toward the next detent position. After the motor has traversed a predetermined percentage of the distance to the next detent position, as indicated by a sensor, a high current level is induced in the lagging phase of the motor so as to provide a decelerating torque. After a predetermined time, the high current is switched from the lagging to the leading phase to cause the motor to reach the next detent position, after which the current in the new detent phase is reduced to a holding level.

Abstract: A multiphase stepper motor is used to position the printhead of a thermal printer. Movement of the printhead is controlled by sequentially enabling adjacent phases of the stepper motor. While enabled, the current flowing in any phase is controlled by a switching regulator. During those periods when the switching regulator is turned off, the decaying current in an enabled phase flows through a flyback diode, the power loss associated with the flyback diode circuit being very small. Accordingly, the decay of current in the inductive phase winding is primarily controlled by the losses of the winding itself. When a phase is disabled, however, and the next phase enabled by the enabling means of the controller, it is desired that the inductive current in the disabled phase rapidly decay to zero. This is accomplished by a circuit in the decaying current path and in series with the flyback diode, this circuit being switchable to a high loss condition during the decaying phase of the inductive current.