US 3,973,662 AGranted

Acceleration control system for high speed printer

AssigneeExtel Corporation

InventorJohn R. Fulton

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Abstract

An all-electronic print rate control system for a high-speed column sequential dot matrix printer, using a permutation code input signal, an input storage register with a capacity of at least three code words, for storing the input data and a print timing oscillator. The control system comprises a print clock, including a plurality of countdown circuits connected to the oscillator, for generating a normal print rate timing signal and a fast print rate timing signal; the print clock can also generate a variable print rate timing signal in which the initial column intervals are longer than in the normal print rate timing signal and the concluding column intervals are preferably shorter than in the normal signal. A print clock control selects one of these print rate timing signals to control the printing speed in each print cycle, depending on printer conditions in the prior cycle; the variable signal is used whenever the printer has actually come to rest for any appreciable interval.

Claims24

Dependent claims

An electronic print rate control system for a high speed column-sequential dot matrix printer utilizing a permutation code data input signal comprising a sequence of code words which, in continuous operation, occur at a given maximum receiving rate, the printer comprising:

a print head and a print head drive for moving the print head through a sequence of a given number of column steps, in each print cycle, at a speed controlled by a print rate timing signal which also controls other printer functions;
an operational storage register including a plurality of stages each capable of storing a code word;
input means for recording each received code word in the storage register;
and output means for reading code words from the register in the same sequence as recorded therein;
the print rate control system comprising:
print clock means for generating:
a normal print rate timing signal of given normal frequency to actuate the printer to reproduce spacing characters at a normal print rate approximately equal to the maximum receiving rate,
a fast print rate timing signal, having a frequency higher than the normal frequency, to actuate the printer to reproduce spacing characters at a fast print rate, substantially faster than the normal print rate, and
a variable print rate timing signal progressively increasing in frequency from an initial frequency substantially lower than the normal frequency to a final frequency at least as high as the normal frequency, during a limited number of print cycles;
and print clock control means, connected to the timing signal generating means and to the printer, for applying one of the print rate timing signals to the printer during each print cycle, each in accordance with different predetermined operating conditions of the printer at the beginning of the print cycle,
the print clock control means applying the variable print rate timing signal to the printer for print cycles in which a spacing character is reproduced following an interval in which the print head has been at rest.

8 more elements

The method of controlling the print rate of a high speed column-sequential dot matrix printer actuated by an input signal comprising a sequence of code words occurring at a maximum input rate, the printer comprising a print head, a print head drive for moving the print head through a number of column steps in a print cycle at a speed controlled by a print rate timing signal, and a multi-stage storage register, each stage capable of storing a complete code word, comprising the following steps:

generating at least two print rate timing signals of constant frequency, including a normal print rate timing signal at a normal frequency to actuate the printer at a normal print rate approximately equal to the maximum input rate and a fast print rate timing signal at a high frequency substantially higher than the normal frequency;
generating a variable print rate timing signal progressively increasing in frequency from an initial frequency below the normal frequency to a final frequency at least as high as the normal frequency;
and selectively applying the print rate timing signals to the printer to control the rate of reproduction of spacing characters in accordance with different operating conditions for the printer,
including applying the variable print rate timing signal to the printer during a print cycle in which a spacing character is reproduced following an interval in which the print head has been at rest.

1 more element

detecting each of the following conditions:
A. a spacing character was reproduced in the preceding print cycle;
B. a new code word was recorded in the storage register at a given time Y in the preceding print cycle;
and
C. a given number of code words, in excess of one, was recorded in the storage register at a given time X, prior to Y, in the preceding print cycle;
D. a new code word recorded in an output stage of the storage register represents a line feed or carriage return function for the printer;
applying a normal print rate timing signal to the printer when conditions A and B are detected but conditions C and D are not detected;
applying a fast print rate timing signal having a frequency substantially higher than the normal frequency to the printer when conditions A and C are detected but condition D is not detected;
and
applying a variable print rate timing signal of progressively increasing frequency to the printer when condition B and D are not detected, independently of whether conditions A or C are detected.

7 more elements

Dependencies are inferred from the claim text.