Bidirectional dual head printer

Claim 2

Control means for operating a printer having at least first and second printer heads each of said heads having a plurality of print wire solenoids for selectively generating dot column patterns; said control means comprising first means for storing and recirculating binary coded data words each representing an alphanumeric character to be printed including means for reinserting the word at the output stage of the first means back into the input stage to cause said first means to operate as a recirculating memory; second means for shifting said words in said first means; third means coupled to said second means for counting the number of shift operations performed; fourth means for temporarily storing a data word; fifth means coupled to said third means for writing the data word appearing at the output stage of said first means into said fourth means without removing the data word from said first means when said third means reaches a predetermined count; character generator means for generating signals representing a dot column pattern for the data word in said fourth means; sixth means responsive to a second predetermined count in said third means for coupling the output of said first means to said character generating means; seventh means for temporarily storing the dot column pattern signals generated by said character generator means when coupled to said fourth means; eighth means coupled to said third means for terminating operation of said second means when said third means reaches a predetermined count, said eighth means including means for coupling the data word in the output stage of said first means to the input of said character generating means; ninth means responsive to said eighth means for simultaneously coupling the outputs of said seventh means and said character generating means to said first and second print heads to print dot column patterns.

Claim 3

The control means of claim 1 further comprising registration means for generating registration signals each representative of the positions at which dot column patterns are to be printed; means for counting said registration signals to generate signals representative of the number of registration signals counted; said character generating means comprising first input means for receiving a data word and second input means for receiving the output of said registration signal counting means for generating a selected one of a plurality of dot column patterns which collectively represent the alphanumeric character to be printed, the dot column pattern being selected being controlled by the count of said timing signal counting means.

Claim 4

The control means of claim 2 further comprising means coupled to said registration signal counting means for resetting said registration signal counting means for activating said second means to shift the next succeeding characters into the output stage of said first means when a third predetermined count is completed and before the next third predetermined count is initiated.

Claim 5

The control means of claim 1 further comprising carriage means for receiving said printer heads, said printer heads being mounted at spaced intervals along said carriage means; means for moving said carriage means in a forward direction; means for moving said carriage means in a reverse direction; first limit means for generating a first limit signal when said carriage means is in its left-hand most position; means for generating a second limit signal when said carriage means is in its right-hand most position.

Claim 6

The control means of claim 4 further comprising means for clearing the first means when either said first or said second limit signal is generated; means for activating said fifth means and seventh means only when said first limit signal is generated.

Claim 7

The control means of claim 5 further comprising 10th means coupled to said third means and responsive to said second limit signal for transferring the data word in the output stage of the first means to the input of said fourth means when a fourth predetermined count is accumulated; 11th means coupled to said third means and responsive to said second limiting signal for disabling said second means and coupling the output stage of said first means to the input of said character generating means when said third means accumulates a fifth predetermined count.

Claim 8

A dot matrix printer capable of printing 2N characters per line where N is a real integer comprising a platen; a reciprocating carriage; means for selectively moving said carriage and in a forward and a reverse direction across said platen; first and second print head means arranged at spaced intervals along the carriage whereby each print head means is adapted to print one-half of the characters on each line of characters; each print head means having a plurality of print wire actuating means for generating dot column patterns upon a paper document supported by the platen as the carriage moves across the platen; a recirculating register having 2N+1 stages for storing 2N binary words each word representing a character to be printed, the N+1 stage of said register being the output stage; means for loading said register with a start character word and 2N character words; means for shifting said binary words through said register; means for counting the number of shift operations; first stage means; first decoding means being enabled responsive to a count of N+1 in said counting means for transferring the word in the said output stage to said first storage means; character generating means having first and second input means and an output for generating successive dot column pattern signals which cooperatively represent a cHaracter responsive to the character responsive to the character word coupled to the first input means and responsive to a dot column position signal coupled to said second input means; second storage means for storing one dot column pattern; said first decoding means further including means for enabling said character generating means to transfer the dot column pattern of the character stored in said first storage means to said second storage means; second decoding means being enabled responsive to a count of 2N+1 in said counting means for disabling said shifting means, said second decoding means including print initiating means for coupling the output stage of said recirculating register to said character generating means first input means and for simultaneously coupling the outputs of said character generating means and said second storage means respectively to said first and second print head means to print the dot column patterns for the first and (N+1)st characters on a line of characters.

Claim 9

A dot matrix printer capable of printing 2N characters per line where N is a real integer comprising a platen; a reciprocating carriage; means for selectively moving said carriage and in a forward and a reverse direction across said platen; first and second print head means arranged at spaced intervals along the carriage whereby each print head means is adapted to print one-half of the characters on each line of characters; each print head means having a plurality of print wire actuating means for generating dot column patterns upon a paper document supported by the platen as the carriage moves across the platen; a recirculating register having 2N+1 stages for storing 2N binary words each word representing a character to be printed, the N+1 stage of said register being the output stage; means for loading said register with a start character word and 2N character words; means for shifting said binary words through said register; means for counting the number of shift operations; first stage means; first decoding means being enabled responsive to a count of N+1 in said counting means for transferring the word in the said output stage to said first storage means; character generating means having first and second input means and an output for generating successive dot column pattern signals which cooperatively represent a cHaracter responsive to the character responsive to the character word coupled to the first input means and responsive to a dot column position signal coupled to said second input means; second storage means for storing one dot column pattern; said first decoding means further including means for enabling said character generating means to transfer the dot column pattern of the character stored in said first storage means to said second storage means; second decoding means being enabled responsive to a count of 2N+1 in said counting means for disabling said shifting means, said second decoding means including print initiating means for coupling the output stage of said recirculating register to said character generating means first input means and for simultaneously coupling the outputs of said character generating means and said second storage means respectively to said first and second print head means to print the dot column patterns for the first and (N+1)st characters on a line of characters.

Claim 10

The printer of claim 7 further comprising registration means for generating position pulses responsive to the movement of said carriage means; means for counting said position pulses; the output of said position pulse counting means being coupled to the character generating means second input means whereby the dot column pattern generated at the output of the character generating means is altered as the counting in said second counting means is incremented.

Claim 11

The printer of claim 7 further comprising means responsive to the operation of said print initiating means for restarting said shifting means.

Claim 14

The method of claim 10 further comprising the steps of: h. linearly moving the print heads during the printing operation; i. monitoring the movement of the print heads for generating position signals representing the position of the heads relative to the paper document upon which the dot matrix characters are being printed; j. controlling the dot column pattern being formed during each converting step by said position signals to sequentially produce N dot column pattern signals for each character where N is a real integer greater than 1.

Claim 15

The method of claim 10 further comprising the steps of: h. shifting the binary groups in the recirculating register until the binary signal group representing the second character to be printed by the right-hand print head is shifted into the outPut stage of the recirculating register; i. temporarily storing the aforesaid signal group in a latch register; j. shifting the signal groups in the register until the signal group representing the second character to be printed by the left-hand print head is shifted into the output stage of the register; k. converting the signal group in the latch register into dot column pattern signals for forming the character represented by the binary signals in said latch register, and storing the dot column signals in an output latch register; l. immediately thereafter, converting the signal group in the output stage of the recirculating register into dot column pattern signals for forming the character represented by the binary signals in the output stage of the recirculating register; m. simultaneously applying the dot column pattern signals to their respective print heads for simultaneously operating the heads.

Claim 16

The method of claim 12 further comprising the steps of: n. clearing the recirculating register when the printing of the line of characters is completed; shifting groups of binary signals into the recirculating register which groups represent the next line of characters to be printed; moving the carriage means in the reverse direction to print the next line of characters thereby eliminating the need for a carriage return operation and whereby alternate lines of characters are printed when the carriage moves in a forward direction and intervening lines of characters are printed when the carriage moves in the reverse direction.