ITX 3000/2000 Printer User Manual
(UMITX315.PDF
)
Page 10 of 82 Date: 4/27/05
Detailed Printer Data
The following is a brief explanation of the process by which the FGL or “G” printer forms the printed image of a
character.
In order to print a simple line of text, each the letter’s graphic image (its pixels) need to be converted into printer dots.
For FGL printer, which has 13 internal fonts, one of these fonts is selected by a command, followed by the test for the
letters to be printed, using that font. For example, to print the word “Text”, in FGL, you would send “<F1>Text”. The printer
has an internally stored image of the dot patterns, for each printer font, and it uses this to print the selected font.
For Raster Graphics, the font selection is made using Windows programming methods. For example, a small Arial font
could be selected for the printable string of “Text” (as in the example above). The Windows GDI, using the Windows Printer
Driver, would then render this character string (convert the each letter’s graphic image, its pixels, into printer dot image data,
and commands). This data would be passed, to the printer, over the interface. The image below shows the graphical data.
Dots: Data (hex)
***** * F8 00 08
* * 20 00 08
* ** * * **** 20 C8 9E
* * * * * * 21 25 08
* ***** * * 23 E2 08
* * * * * 21 05 08
* ** * * ** 20 C8 86
Thus “Text” is converted to 7 rows of 3 bytes each. In addition, the Raster language requires a command prefix of at
least 2 characters, so each line is at least 5 bytes. This results in 35 bytes from the Raster Graphic driver, whereas only 8 data
bytes are required with FGL. For larger fonts, the difference can be 100:1, or more.
The Windows Raster programming method allows the use of any Windows font or graphic without special commands.
To support this larger data payload the “G” version printer has its electronic hardware, firmware and driver organized to handle
this very efficiently. Both modes have similar throughput. Note also that its is possible to change the operating mode of the
printer by simply downloading the preferred firmware to the printer.