The HP iMFP won't show that it is receiving any data from the card swipe.  The same card reader works fine when tested on a PC Pharos Station or when simply attached to computer.

Blog Post created by toleary on Aug 8, 2013

Since the Magtek Reader is working on the PC Release Station that would mean it is set up for Keyboard Emulation.

In order for it to work properly with the HP iMFP it would need to be set up for HID Mode.

You can change the configuration by plugging the card reader into a computer, and navigating to this webpage:

Magtek Online Card Reader Configuration