USB2 is a faster version of USB1. USB2 equipment will run using USB1, but its speed will be restricted to the USB1 speed. With a printer, that might not be a problem because the limiting thing is probably the printer itself, not the speed the signal gets to it.
I'm not sure how you can check if you've got USB2 or 1 on your PC at the moment. Hopefully someone else will help you with that.