The process is very similar to the type of dry process photocopier first produced by Xerox.
An electric charge is first sprayed onto a revolving drum by a corona wire. The drum has a surface of a special plastic or garnet. Electronics drives a system that writes light onto the drum. The light causes the electrostatic charge to leak from the exposed parts of the drum. The surface of the drum passes through a bath of dry plastic powder. The charged parts of the drum electrostaticaly attract the particles of powder. The drum then deposits the powder on a piece of paper. The paper passes through a fusor, which bonds the plastic powder to the paper.
Each of these steps has numerous technical choices. One of the more interesting choices is that most "laser" printers actually use a linear array of light-emitting diodes to write the light on the drum. The toner can be either wax or plastic. The paper can be oppositely charged, or not. The fusor can be an infrared oven, a heated roller, or (on some very fast, expensive printers) a xenon strobe.
The slowest printers of this type print about four pages per minute, and are inexpensive. The fastest print mass mailings (commonly for utilities) at several thousand pages per minute.
The cost of this technology depends on a combination of costs of paper, toner replacement, and drum replacement. Often printers with soft plastic drums can have a very high cost of ownership that does not become apparent until the drum requires replacement. Follow manufacturer's instructions on replacing these components.
One helpful trait is that in very high volume offices, a duplexing printer, that prints both sides, can often halve paper costs, and reduce filing volumes and floor weight as well.
Many premium units also have a toner-conservation mode. It can be substantially more economical at the price of only slightly lower contrast.
Aside from these components, typical maintenance is to vacuum the mechanism, and eventually clean or replace the paper-handling rollers. The rollers are rubber, and eventually become covered with slippery paper dust. They can usually be cleaned with a damp lint-free rag.