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AFP and Impact Printers

Advanced Function Printing (AFP) was developed to enable new functions supported by page printing technology which provided better control of the placement of print on the page than earlier line printing technology. It can also simplify the task of redirecting the printed output from an application to a different target printer supported by the AFP architecture.

How do Impact Printers fit in the AFP world?

Impact printers are printer which generate print by hitting ink, usually from an inked ribbon, onto the output page. Unlike page printers, they normally print one line at a time rather than a page at a time. However, some impact printers are supported by AFP.

AFP-supported impact printers do not typically support downloadable character sets although they do support selection of printer-resident character sets. Usually, they do not support multiple print orientations. They may support graphics but the resolution is usually not as good as that produced by page printers.

Font Support

In the AFP environment, a "coded font" is defined as the combination of a "code page" and a "character set".

A "code page"
is used to map the characters in the print data stream into characters within
a "character set",
which is a group of character shapes supported by the printer.

"Code pages" and "character sets" are usually downloaded from the host to the printer for non-impact printers. For impact printers, fonts are supported via tables that map host "code pages" and "character sets" to printer resident resources. Although it is possible to create new "coded fonts" by combining "code pages" and "character sets" in different combinations, the corresponding hardware resources must exist on the printer.

More about font mapping tables

Why?

The AFP architecture supports highly reliable printing - the printer can participate in error recovery so that, even in the event of disastrous power outages, error recovery is maintained and loss of data is prevented. The application can still achieve some level of printer independence within the capabilities of the impact printer. Also, impact printers can be cheaper than page printers and some people actually prefer them.
Big Iron