Printing a simple webpage on a Dot Matrix printer

I'm trying to figure out how to get a webpage (Specifically http://sandbox.daveblencowe.com/pos/invoice.html) to print on a Dot Matrix Printer (oki microline 1190). So far I've understood I need to convert the page to ASCII but I'm unsure how to do that and maintain the spacing (It's printing to a 3 part invoice template (DUKSA002)).

Any help would be greatly appreciated.

The Microline 1190 has a printwidth of 80 characters, so you need to wrap your page around a maximum width of 80 as well. Also, you need to find out the maximum rows you may add to one page. If you have a preprinted form, to which this needs to be printed, you should add or remove spaces, until it fits your form.