Mark:
It seems to me the process to support your printer would not be at all unlike handling bitmapped fonts for a graphics LCD display. I have posted a some Keil C-51 code for handling bitmapped font tables for LCD display modules on my 8052.COM user page. The code works by having an in memory bitmap buffer that maps to the physical device. Then there are higher level functions to draw lines, texts, and boxes into the bitmapped buffer and lower level routines that support copying the buffer out to the physical device. I would invite you to visit my page at:

Karas User Page

....and look for the article Using Bitmapped Fonts With a Graphics LCD Module. The code download links are on that page.

Hope you can find that useful to your printer application.

Michael Karas