Some websites may choose the printer by default. Are you getting a system dialog that pops up giving you options? The website may have changed the option to do this as well.

Try using { Ctrl + P } or File > Print to initiate printing. The dialog that appears allows you to select a different printer, which isn't possible from Print Preview that you get first when using the Print toolbar button.

By pressing control P, it automatically prints. I am trying to process some packing slips through a website we use for orders (SHIPSTATION) and before I updated Mozilla, it worked fine. I would select the order and be able to print any pages and what printer too. Now when I select print, it just automatically prints to my label maker. I have to download it into a pdf in order to print it the way I want it to(or how it use to).