Epson FX-185 User Manual - Page 149

A final multiplication: 480 main columns X 792 rows gives you a grand total of 380,160 dot positions per FX-80 page. And that doesn't even take into account intermediate columns, the FX-100's ability to print 136 Pica matrixes, or both models' ability to use graphics density settings to increase the number of dots across the page and microscopic line spacing to increase the number of dots down the page. Since there is a huge number of such dot positions on each page, this sounds like a giant task. It won't be, however, because we'll give you methods to shorten the time and steps to good graphics design. Print Head Printing high-resolution graphics on the FX requires a mode that is very different from the text modes. In any of the several versions of Graphics Mode, none of the predefined characters or symbols in the printer's memory are used. Instead, you create the patterns of dots that are printed. Thus, you control where and when each and every dot is printed. To do this, you look at the page as a series of dot columns, arranged in rows. For each column position on a print line, the print head impresses the pattern of dots that you have specified. Before you can start designing these patterns, however, you need to know a little more about the way the print head works. Even though there are nine pins on the print head, each column can be only eight dots high. That's because printer/computer communications are based on eight data lines, with each of the top eight pins of the print head corresponding to one of the eight lines. So each sweep of the head prints eight or fewer dots, depending on your computer system and your specifications (see Figure 10-1). Seven-bit systems can control only the middle seven pins. Because we want users of such systems to be able to use these programs, we rarely put the top pin to work in the programs that follow. When we do, we tell you so. 132