US 3,938,641 AGranted

Control system for high speed printer

AssigneeExtel Corporation

InventorJohn R. Fulton

Life of this patent

Estimating the term…

Loading patent…

Abstract

An all-electronic control system for a high-speed column sequential dot matrix printer, using a permutation code signal of given pulse rate p comprising a series of individual code words each including a fixed number of data pulses preceded by a start pulse; the control system comprises a plural-stage FIFO storage register with a capacity of at least three, and preferably four or more, code words, for storing input data, as during a carriage return of the printer. A print timing oscillator having a frequency f is coupled to countdown means that develops a normal print rate signal f/n and a fast print rate signal f/m, where f >>p and n>m. A print rate selector selects one of the print rate signals, to control the printing speed of the printer, depending on whether a code word is stored in a given stage of the storage register.

Claims13

Dependent claims

An electronic print rate control system for a high-speed column-sequential dot matrix printer actuated in accordance with a permutation code signal of given pulse rate in which each code word, representative of a character to be reproduced or of a non-print function, includes a given number of data pulses, the printer comprising a print head, print head drive means for stepping the print head through a plurality of column movements in each spacing character cycle, a print timing oscillator having an operating frequency f much higher than the pulse rate of said permutation code signal, a plural-stage FIFO storage register, each stage having a capacity sufficient to record a code word, means for recording each code word in the storage register, and means for reading out the code words from the storage register in the same order as received, the print rate control system comprising:

first countdown means, coupled to the print timing oscillator, for developing a normal print rate signal having a frequency f/n;
second countdown means, coupled to the print timing oscillator, for developing a fast print rate signal having a frequency f/m, where n and m are integers and n>m;
and print rate selection means for selectively applying one of the print rate signals to the print head drive means to control the rate of column movements, in each spacing character cycle, in accordance with the presence or absence of a code word recorded in a given stage of the storage register.

An electronic print rate control system for a high-speed column-sequential dot matrix printer actuated in accordance with a permutation code signal of given pulse rate in which each code word, representative of a character to be reproduced or of a non-print function, includes a given number of data pulses, the printer comprising a print head, print head drive means for stepping the print head through a plurality of column movements in each spacing character cycle, a plural-stage FIFO storage register, each stage having a capacity sufficient to record a code word, means for recording each code word in the storage register, and means for reading out the code words from the storage register in the same order as received, the print rate control system comprising:

means for generating a normal print rate signal of fixed frequency to actuate said printer to reproduce characters at a normal print rate approximately equal to the rate of receipt of code words;
means for generating a fast print rate signal of mixed frequency to actuate said printer to reproduce characters at a fast print rate, substantially faster than said normal print rate;
and print rate selection means for selectively applying one of the print rate signals to the print head drive means to control the rate of column movements, in each spacing character cycle, in accordance with the presence or absence of a code word recorded in a given stage of the storage register.

Dependencies are inferred from the claim text.