Envy 7640 will not print pdf's. It will print Word docs. All drivers etc. have been updated. When trying to print pdf's it will act as though it is spooling, spits out one blank piece of paper and acts as though it has printed what was asked for. Sometimes it will say "printing cancelled". I have also unplugged printer to reset. Nothing seems to correct problem.
What program are you using to print the PDF's? I have seen several cases where using Adobe Acrobat Reader DC resolved printing issues from other pdf programs. You can download the free reader from Adobe here: https://get.adobe.com/reader/. Review the optional offers, you may want to uncheck these.