It saves to a .prn file when I want to print a .pdf file

It saves to a .prn file when I want to print a .pdf file to SHARP MX-3640N printer

Solution:

Open the .pdf file you want to print.
Click File/Print.
Click Advanced. There is no tick mark against 'Print to File'.
Tick it. Click OK. Click Print. 'Print to File' popup box appears. Click 'Cancel'.

Click File/Print/Advanced again. Clear the tick against 'Print to File'. Click OK.
Click Print. It prints successfully.