Just a thought here, I'm not an electrician or EE but have maintained a house for 40 years...

Try plugging your printer into a different circuit than you are currently using (i.e. one in a completely different part of the house not on the same breaker). You may have a hot and neutral or neutral and ground crossed somewhere in the circuit. I had a similar problem once- a slight but definite tingle while touching a light fixture housing during a bulb change. Took me a long time to find the culprit, but a neutral had worn off insulation in a bathroom exhaust fan due to vibration and was touching the metal housing.

Could be something as simple as changing the circuit you are using could fix the problem with your printer.