HP C3180 All-in-One Not Printing

[DPHMac]

I have an HP C3180 All-in-One printer. It worked fine for a year. However, now it won't print or scan, from my MAC. When I go to print a document, it acts as if it's printing, via the print monitor, but then nothing actually prints. Once in a long while something will print. The printer will make copies (a la an office copier) so the printer itself is clearly working mechanically. I have double-checked all the connections and tried different cables to no avail. I have also reinstalled the printer software (twice) with no luck.