A B717 flight crew declared an emergency and diverted to the nearest suitable airport due to a smoking ACARS printer.

Narrative

At FL330 both the First Officer and I smelled an odor. After about a minute we realized it was originating in the cockpit. We determined it was coming from the ACARS printer. Visible smoke was beginning to fill the First Officer's side of the cockpit. A very strong electrical 'burning' smell was present. We donned oxygen masks and completed the electrical smoke/fire QRH checklist. I declared an emergency and requested a diversion to an airport which was in sight off the nose. We began a descent. The checklist directs the crew to transition the aircraft to emergency power through several steps. At that point I hand flew the aircraft. The Lead Flight Attendant secured the cabin and prepared the cabin crew and passengers. We were vectored for a visual approach to the runway. After we transitioned to emergency power the ACARs printer was un-powered; smoke accumulation in the cockpit ceased; and only the odor and residual smoke remained. The lead Flight Attendant informed us at some point prior to landing that one passenger was having a panic attack and was receiving oxygen. We requested EMTs standing by for our arrival at the gate. After landing; emergency equipment followed us to the gate where we deplaned. The First Officer noticed that the ACARS printer was 'hot' to the touch as we completed our post flight.