Abstract: A ribbon tension control for controlling the tension of ribbon traveling between a rotating supply spool and a rotating take-up spool varies the amount of braking torque applied to the supply spool to hold ribbon tension constant as the distribution of ribbon between the spools changes. A generator rotationally coupled to the supply spool produces braking torque to resist the rotation of the spool when the generator windings are electrically loaded. The loading of the generator is controlled by processing feedback signals emitted by the generator to provide periodic load switching signals. Processing of the feedback signal is accomplished in the exemplary embodiment by a drag lookup table which is addressed by the feedback signal. The drag lookup table produces a duty cycle value which is used to determine the duty cycle of the switching signal, which, in turn, controls the electrical loading of the generator.

Abstract: A dot matrix print head control circuit is capable of selectively requesting and receiving a predetermined set of print head control data from a digital data processor which successively transmits plural sets of such digital data and corresponding data acknowledge pulses in response to a data request signal. The microprocessor is thus enabled to independently control two print wire arrays in a dot matrix print head using identical circuits which are thus more economically formed as LSI chips. Each such identical print head control circuit has a "role determining" circuit which can be initialized such that its associated print head control circuit, although identically constructed, is capable of selecting a predetermined set (e.g. byte) of digital data from among the plural sets (e.g. bytes) of digital data transmitted in succession by the microprocessor. The identical print head control circuits are thus capable of effecting different print functions in response to the selectively received data set.

Abstract: Use of a programmable source of stepping pulses to control the speed of linear movement of a material from a supply spool to a takeup spool wherein feedback signals provide an indication of the angular velocity of the supply spool and a function table provides information on the rate of stepping pulses to be applied to the takeup spool.

Abstract: A dot matrix printer has a programmable interval counter which produces motion control pulses for stepping the stepper motor of a print head carriage and/or of a paper advance system. The same motion control pulse which is used to control the carriage step motor is also input to a microprocessor, in an open loop fashion, to request further print head data for driving the wire array(s) of the dot matrix print head. A programmed time delay may be introduced between the programmable interval counter and the carriage step motor to compensate for wire flight time of the print head wires in a manner which is substantially independent of carriage velocity. A variable delay may also be introduced between the programmable interval counter and the microprocessor to compensate for carriage motor shaft lag/lead.

Abstract: In a drive circuit for an electromagnetic printing element of a matrix impact printer, a drive pulse drives the printing element from the backstop toward a record medium to print indicia, and a damping pulse, applied to the printing element after its return to the backstop, urges it toward the backstop to limit rebound therefrom. Logical control circuitry is responsive to overlap of a drive pulse with a preceding damping pulse for terminating the damping pulse and for decreasing the width of the drive pulse in proportion to the amount of overlap. Blanking means are provided to prevent application of a damping pulse to the printing element until after the completion of a preceding drive pulse and after impact of the printing element with the record medium and with the backstop.

Abstract: An arrangement for processing data by modifying selected bit portions of coded control signals for comparison with coded input signals to control printing by a printer.

Abstract: A regulator for a two phase shaft encoder used in sensing irregular body movements which determines when the light transmission of a photocoupler is maximum and corrects the photocoupler output to agree with a reference value.

Abstract: Print control apparatus which combines a first in - first out memory for storing received data with a random access memory for feeding data to a movable type printer to eliminate the need for suspension of receiving input characters or the adding of fill characters or time delays during the period when printer action is suspended during execution of control actions, such as paper feed. The apparatus controls the transfer of data from the first in - first out memory to the random access memory by keeping the latter memory continuously replenished with data as the printer executes its printing action and printed characters are erased from the random access memory.

Abstract: An arrangement for detecting a change in the number of printing characters associated with a set of such characters employed in a printer and for automatically modifying the print control algorithm employed in the printing process in accordance with said detected change.

Abstract: Maximizing the printing rate of an electronic printer by causing it to print data characters at a relatively constant rate despite variations in the pattern of the incoming data. The number of characters in an incoming data pattern to be printed substantially simultaneously is monitored and the printing rate controlled within certain limits to provide a maximum printing rate consistent with the power and mechanical limits of the printer design.