Do you get the same issue if you try printing to a PDF printer driver -- is the output grainy in the PDF? If you do not have the Adobe Acrobat PDF software, here are some free PDF printer programs to consider:

• PrimoPDF: http://www.primopdf.com/
• PDF Creator: http://www.pdfforge.org/download

(If you are viewing the information you want to capture inside Firefox, this add-on can capture it to PDF, although despite the name, this does not use Firefox printing so doesn't really address the question at hand: Print pages to PDF.)

Although it doesn't seem obvious, Firefox's option to use hardware graphics acceleration can affect fonts. Usually the problem is manifested on screen, but it might help to disable this feature and see whether it affects the printouts as well.

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the filter box, type or paste gfx and pause while the list is filtered

(3) Double-click gfx.direct2d.disabled to toggle its value from false to true (it should turn bold). This is the one for which there is a checkbox in the options dialog.

(4) Double-click gfx.content.azure.enabled to toggle its value from true to false (it should turn bold).

You usually need to restart Firefox before this takes effect.

Also... The forum software detected your Firefox as version 17. Is that correct?

Version 17 is not secure; Mozilla discloses security flaws after each new release. Is something holding you back from upgrading to Firefox 21? Please let us know so we can suggest solutions or workarounds.

If Help > About Firefox shows Firefox 21.0, you may need to clear the preference that is misreporting your version number. See: How to reset the default user agent on Firefox.

I have the latest firefox 21.0

I do have adobe acrobat and ive tried this (1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the filter box, type or paste gfx and pause while the list is filtered

(3) Double-click gfx.direct2d.disabled to toggle its value from false to true (it should turn bold). This is the one for which there is a checkbox in the options dialog.

(4) Double-click gfx.content.azure.enabled to toggle its value from true to false (it should turn bold).

You usually need to restart Firefox before this takes effect.

and it did not work

Is the PDF grainy, or is the issue printing to the "real" printer?

Could you also try Firefox's Safe Mode? That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?