Stored energy printer
Encyclopedia
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. As compared to dot matrix printers that print a single column of dots at a time, these printers generally print an entire line of dots at a time and so are sometimes called line matrix printer
s.
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 most common printers to use this technology were the line-matrix printers made by Printronix
and its licensees. In these, the hammers were arranged as a "hammerbank," a sort of comb that oscillated horizontally to produce a line of dots.
A character matrix printer has also been produced. In this printer, the hammer
s were machined from an oval of magnetically-permeable stainless steel, and the hammer-tips form a couple of vertical rows.
The original technology, patented by Printronix in 1974, was to have the top of a stiff leaf spring
held back by a magnet
ic pole-piece. A tungsten carbide
hammer would be brazed
to the center-top of the leaf spring. When it was desired to produce a dot, a coil (electromagnet
) wrapped around the pole-piece would neutralize the magnetic field. The leaf spring would snap the hammer away from the pole-piece, pushing the hammer out against a ribbon and push an image of a dot onto the paper.
Recent designs have performed complex optimizations in the magnetic circuit, and eliminated unwanted resonance
s in the spring. The result was a near-doubling of speed. Other improvements include the use of electrical discharge machining
to produce complex, three-dimensional hammers that trade-off the magnetic circuit, mechanical resonances, and printing speed.
Normal wear usually occurs when 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 speeds and improved life-span tenfold to something like a billion impressions per hammer.
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...
that uses the energy stored in a spring or magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
to push a hammer through a ribbon to print a dot. As compared to dot matrix printers that print a single column of dots at a time, these printers generally print an entire line of dots at a time and so are sometimes called line matrix printer
Line matrix printer
A line matrix printer is a computer printer that is a compromise between a line printer and a dot matrix printer. Basically, it prints a page-wide line of dots. It builds up a line of text by printing lines of dots.-Applications:...
s.
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 most common printers to use this technology were the line-matrix printers made by Printronix
Printronix
Printronix is an independent supplier of line matrix, Thermal Bar Code printer, radio frequency identification and mobility solutions. Printronix printers are typically used for bar code labeling of products, as well as high-volume printing of reports...
and its licensees. In these, the hammers were arranged as a "hammerbank," a sort of comb that oscillated horizontally to produce a line of dots.
A character matrix printer has also been produced. In this printer, the hammer
Hammer
A hammer is a tool meant to deliver an impact to an object. The most common uses are for driving nails, fitting parts, forging metal and breaking up objects. Hammers are often designed for a specific purpose, and vary widely in their shape and structure. The usual features are a handle and a head,...
s were machined from an oval of magnetically-permeable stainless steel, and the hammer-tips form a couple of vertical rows.
The original technology, patented by Printronix in 1974, was to have the top of a stiff leaf spring
Leaf spring
Originally called laminated or carriage spring, a leaf spring is a simple form of spring, commonly used for the suspension in wheeled vehicles...
held back by a magnet
Magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.A permanent magnet is an object...
ic pole-piece. A tungsten carbide
Tungsten carbide
Tungsten carbide is an inorganic chemical compound containing equal parts of tungsten and carbon atoms. Colloquially, tungsten carbide is often simply called carbide. In its most basic form, it is a fine gray powder, but it can be pressed and formed into shapes for use in industrial machinery,...
hammer would be brazed
Brazing
Brazing is a metal-joining process whereby a filler metal is heated above and distributed between two or more close-fitting parts by capillary action. The filler metal is brought slightly above its melting temperature while protected by a suitable atmosphere, usually a flux...
to the center-top of the leaf spring. When it was desired to produce a dot, a coil (electromagnet
Electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. The magnetic field disappears when the current is turned off...
) wrapped around the pole-piece would neutralize the magnetic field. The leaf spring would snap the hammer away from the pole-piece, pushing the hammer out against a ribbon and push an image of a dot onto the paper.
Recent designs have performed complex optimizations in the magnetic circuit, and eliminated unwanted resonance
Resonance
In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
s in the spring. The result was a near-doubling of speed. Other improvements include the use of electrical discharge machining
Electrical discharge machining
Electric discharge machining , sometimes colloquially also referred to as spark machining, spark eroding, burning, die sinking or wire erosion, is a manufacturing process whereby a desired shape is obtained using electrical discharges...
to produce complex, three-dimensional hammers that trade-off the magnetic circuit, mechanical resonances, and printing speed.
Normal wear usually occurs when 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
Hexavalent chromium
Hexavalent chromium refers to chemical compounds that contain the element chromium in the +6 oxidation state. Virtually all chromium ore is processed via hexavalent chromium, specifically the salt sodium dichromate. Approximately of hexavalent chromium were produced in 1985...
chrome plating
Chrome plating
Chrome plating, often referred to simply as chrome, is a technique of electroplating a thin layer of chromium onto a metal object. The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness.-Process:A component to be chrome plated will...
on the pole-piece, combined with careful design, more than doubled speeds and improved life-span tenfold to something like a billion impressions per hammer.