Are you having trouble printing from Windows inside Parallels on a Mac? This might solve the problem:
First, make sure Parallels has installed the printer in Windows. If not, then you will need to run the installation software for your printer.
If you've installed the software, but still can't print, you may need to force Parallels to play nice. In some cases, you can simply use the "Devices" menu at the top of the Parallels window. Inside, choose USB and force it to Windows.
That did not work for me, for whatever reason. But, what DID work was to put Parallels in Windowed mode, then find the USB icon (shown below):