Gemini Industries Printer user manual PkNT Matrix

Fundamentals of Dot Matrix Printkg

Figure 6-3. The nine rows of the matrix correspond to the nine pins on the print head. For this uppercase letter, only the top seven pins fire - all at once for each vertical line in this letter, and a single pin (firing repeatedly as the print head moves sideways) for the horizontal line.

This printing technology is called impact, dot matrix printing. Dots are printed according to a predesigned matrix or grid system. Each letter, numeral, punctuation mark, and other special character is formed by the arrangement of 4 to 36 dots.

The firing patterns for each character are pre-programmed in Gemini and stored in “firmware” (ROM’s). By sending the appropriate control codes to Gemini, we manipulate both the number of pins fired and the order in which they are fired. If you know which control code to send from your computer’s keyboard, through the computer to the printer, you can even create new “characters” by controlling the firing pins.

THE PkNT MATRIX

Let’s turn to Appendix K and look briefly at the dot patterns of the various characters. All these characters, during the “normal” printing mode (standard and italic), are constructed within a !5dot- wide by g-dot-high matrix of “boxes?All the dots are positioned vertically within one of the “boxes” in each column in the matrix.

Horizontally, the dots can be placed within any or all of the five boxes across the row or on the lines separating the boxes. If you thinkof the five boxes in a row as the “white” keys on a piano and the lines between them as four “black” keys, you can “play” a dot in any of the nine dot positions across a row. Thus, even

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