Epson SQ-2550, SQ-850 Dot patterns, Eight-elementgraphics, Software and Graphics, Twenty-four-elementgraphics

Graphics

Dot patterns

Your printer’s print head is able to print graphics as well as text because graphic images are formed on the printer about the same way that pictures in newspapers and magazines are printed. If you look closely at a newspaper photograph, you can see that it is made up of many small dots. Your printer also forms its images with patterns of dots, as many as 360 dot positions per inch horizontally and 180 dots vertically. The images printed by the printer can, therefore, be as finely detailed as the ones at the beginning of this section.

Eight-element graphics

So that it is compatible with the many programs written for such printers such as the EPSON FX, RX, LX, and EX series, the printer has an S-element graphics mode with six densities. Although this mode uses only one third of the printer’s nozzles, it produces good quality graphics and allows you to use the many programs written for 8-element graphics.

Twenty-four-element graphics

The graphics mode that takes full advantage of the printer’s print head is 24-element graphics. It has five densities, but for simplicity this explanation will begin with only one of them, triple-density.

Triple-density prints up to 180 dots per inch horizontally. As the print head moves across the paper, every 1/180th of an inch it must receive instructions about which of its 24 nozzles to fire. At each position it can fire any number of nozzles from none to’

24.This means that the printer must receive 24 bits of information for each column it prints. Since the printer uses 8-bit bytes of information in its communication with a computer, it needs three bytes of information for each position.

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