Stored energy printer

A stored energy printer is a type of computer printer that uses the energy stored in a spring or magnetic field to push a hammer through a ribbon to print a dot.

This technology is used to produce premium impact printers, that print for millions to billions of dots per hammer. The advantage of this technology is that it has the lowest known cost of ownership: ink is transferred by conventional typewriter-style ribbons, and the rest of the printer simply never wears out.

The technology is most frequently seen in premium line matrix printers, especially. It is also in a few very-high orce

The original technology, patented by Printronix in 1974, was to have the top of a stiff leaf-spring held back by a magnetic pole-piece. A tungsten-carbide hammer would be brazed to the center-top of the leaf-spring. A coil wrapped around the pole-piece would neutralize the magnetic field. The leafspring would snap the hammer away from the pole-piece, pushing the hammer out against a ribbon and push an image o fa dot onto the paper.

Recent designs have performed complex optimizations on the magentic ciricuit, and eliminated unwanted resonances in the spring. The result was a near-doubling of speed. Basically, the recent designs have used electron discharge machining to produce complex, three-dimensional hammers.

The way the mechanism normally wears is that the spring rubs against the pole-piece as it returns. This causes the pole-piece to wear, eventually requiring the pole pieces to be reground and recertified.

Hexavalent chrome plating on the pole-piece, combined with careful design, more than doubled dpeeds.