How do the police take fingerprints at the police station?

Depends on how advanced their systems are and why they are taking the prints. If you have been arrested the most advanced system is called "LiveScan".

Using a scanner the prints are taken, one finger at a time, a set of finger together and often palm prints.

The machine tells the person scanning if the print is good enough for comparison.

They system automatically files the prints under the name and Demographics listed on the arrest report.

It sends the prints to the local, state and Federal AFIS for gross comparison. The AFIS spits out comparable prints for a technician to make a match, if any.

If no machine the prints are taken on prints cards with inked fingers. Normally at lest 2 cards are taken, one for local check and one for Federal check. The local check can easily take a day or two. Teh Federal check can take weeks because of volume.

If not an arrest situation where the subject needs the prints for a clearance check and such they make one or two cards with ink as needed. The subject then gives the prints to the potential employer or whoever for a check.

Many private companies are authorized to take prints on a live scan system for clearance checks and they are hooked up directly to those systems.