Even if you could gain direct access to your users printer, writing your code to handle the 1/2 a zillion different printers on the market, handle the selection of paper sizes available A3, A4, A5, foolscape etc. Color or b&w, draft mode, letter quality, photo-realistic, margins, headers and footers.

Not to mention that whilst you might think that your data look great in 14pt Ariel, that font might mot be available for the printer in question, and besides, I prefer much smaller fonts. Others may prefer (or require) to use much bigger fonts. You might think it important to have your creative, 1/4 page logo appear on every sheet, but you wouldn't many thanks from me if you did this:)

Offer a "printer friendly icon" which presents the data as cleanly and simply as possible Preferably without using tables for positioning, or at least without artificially limiting the width of the overall tables or individual columns. That way, If I choose to print in landscape on A3 paper so that 'wrapped' contents of table columns gets printed onto single lines, I can do so.

For the rest, save yourself time and your users frustrations by letting the browser, the printer driver and the user decide how they want the data printed, rather than trying to do it your way.

Actually, that is pretty good advice for presenting web pages too.