Your printer has this thing called a "queue." Documents that are to be printed are added to this queue, and if any errors occur or anything happens that halts printing without sending a cancel job order, it will print the next thing in line as soon as it can. Usually when a printer runs a blank sheet after printing, a large blank footer or something has created a new page and the printer will run it just because the computer is telling it to print all of the pages. This could be the case, or if the manual was a PDF, most manuals have blank pages at the beginning and end, resulting in a blank sheet before/after printing. Also try this:
Start
Settings
Control panel
Click administrative tools
Click services
Scroll down to printer spooler
Click stop
Click restart