Dot-matrix printer with pattern checking and pattern correcting means

Claim 1

A dot-matrix printer comprising: buffer memory means adapted for storing a dot character pattern including a plurality of dot pattern data which has been input through an external unit, and a character code corresponding to the dot character pattern; pattern-correcting means for receiving from said buffer memory means first and second adjacent dot pattern data from the same line of said dot character pattern in a printing direction, and for selectively erasing a dot from one of said first and second dot pattern data when said data from said one of said first and second dot pattern data is adjacent a dot from the other of said first and second dot pattern data; register means for storing the corrected data produced by said pattern-correcting means; pattern-checking means for comparing the data stored in said register with data representing said first dot pattern data, and for generating, when the data stored in said register is different from said first dot pattern data, a check signal indicating contact between any two adjacent dots of said first dot pattern data which are arranged in said printing direction; control means for detecting, upon receipt of said check signal from said pattern-checking means, when any two adjacent dots of said first dot pattern data which are arranged in said printing direction are in contact, and then causing said pattern-correcting means to transfer the data from said register means to said buffer memory means; and printing means for printing a dot character pattern read from said character memory means is accordance with printing data input through said external device.