US 4,028,669 A · Printer control system

Abstract

A printer control system is disclosed for receiving data in the form of binary bits over a transmission line from a central processing unit, said data divided into characters to be printed, the control system comprises a rotary drum printer and a control circuit for directing the printer to print the characters. The control circuit has a storage means for receiving and storing the data, a drum trace means for providing an output and dependent upon the drum position, a comparator means for comparing, a character at a time, the data stored in the storage means with the drum position, a serial shift register for storing match and non-match signals between the data to be printed and the drum position and a trigger means for firing, after all stored characters have been compared with the drum position, those hammers of the printer which correspond to the matches between the data and the drum position. The characters are similarly compared to the next drum position and so on until the drum makes a complete revolution by which time all characters have been printed. In addition, the storage means comprises a memory which is divided into halves and the printer control circuit writes into one half the data received and prints the data stored in the second half and includes means for controlling into which half of the memory data is being written and out of which half data is being read.

Claims28

Dependent claims

A printer control system for a rotary drum printer for printing data, said data comprising bits divided into characters to be printed, said rotary drum printer having a plurality of columns of characters distributed in rows therealong for printing said characters of data and having hammers associated with each column being controlled by said system, said system comprising:

storage means for receiving and storing said data;
drum trace means for providing a drum trace signal dependent upon a position of said drum;
comparator means connected to both said storage means and said drum trace means for comparing said data, a character at a time, to said drum trace signal and for providing a match signal when there is a match of said data character and said drum position and a non-match signal where there is no match;
serial shift register means for shifting and storing match and non-match signals, including a serial shift register and means for supplying to said shift register a column finish signal before a comparison operation is started and for supplying said column finish signal out of said serial shift register when said serial shift register is full of match and non-match signals and means responsive to said column finish signal for terminating said comparison operation;
and,
trigger means responsive to said match signals stored in said serial shift register for firing only those hammers corresponding to said match signals after all characters, stored in said storage means, have been compared with said drum position.

3 more elements

A printer control system for a rotary drum printer for printing data, said data comprising bits divided into characters to be printed, said rotary drum printer having a plurality of columns of characters distributed therealong in rows for printing said characters of data and having hammers associated with each column being controlled by said system, said system comprising:

pulse supply means for generating a succession of scan A and scan B pulses;
storage means for receiving and storing said data including a memory, a write address means responsive to scan B pulses for storing said data in said memory, read address means responsive to scan A pulses for supplying said data out of said memory and write pointer means for dividing said memory into first and second halves, in responsive to scan A and for controlling pulses, into which half said data is stored and out of which half said data is supplied;
drum trace means for providing a drum trace signal dependent upon the position of said drum;
comparator means for comparing said data supplied out of said memory to said drum position for providing a match signal when there is a match between the data supplied out of said memory and said drum position and a non-match signal when there is no match;
and
hammer control means responsive to said match signals for firing only those hammers corresponding to said match signals after all data characters have been compared with said drum position.

3 more elements

pulse supply means for generating a succession of scan A and scan B pulses;
storage means for receiving said storing said data including a memory, a write address means responsive to scan B pulses for storing said data in said memory, read address means responsive to scan A pulses for supplying data out of said memory;
drum trace means responsive to scan B pulses for providing a drum trace signal dependent upon a position of said drum;
comparator means connected to said storage means and said drum trace means for comparing during a scan B pulse said data, a character at a time, to said drum trace signal and for providing a match signal when there is a match of said data character and said drum position and a non-match signal when there is no match;
serial shift register means for shifting and storing said match and non-match signals, said serial shift register means having an output corresponding to each of said signals;
a plurality of logic gates, each gate having a first input connected to a corresponding output from said serial shift register means, a second input, and an output connected to said printer;
and,
firing means connected to the second inputs of said plurality of said logic gates and responsive to the next succeeding scan A pulse for firing only those hammers corresponding to said match signals after all characters, stored in said storage means, have been compared with said drum position.

5 more elements

Dependencies are inferred from the claim text.

Printer control system

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Printer control system

Life of this patent

Abstract

Claims28