Each printer is equipped with only one universal printer print head, in large-scale applications, often with higher performance of a line printer, also known as "shuttle" or "comb" type printer. It is the more (for example, 44 or more) of the print pin mounted transversely in a row comb plate, so that each needle only responsible for one line print job a few characters, comb plate (with all print pin) reciprocate about sports, when a needle reaches the position a little to be printed through to its solenoid coil to provide a pulse current to make it a point to complete the printing operation. Combs each completed a move to the left or right, on the printing paper to print out all the information on the complete line of a dot matrix, and then control the printing paper to move away from a printing point by the paper feed mechanism, you can start the next line of dot matrix printing process information