An electrofax was a type of fax. It involved electrostaticprinter and copier technology, where an image was formed directly on the paper, instead of first on a drum, then transferred to paper, as it would be in xerography. It was used in the United States from the 1950s through the 1980s.
The paper used in this process was coated with a zinc oxide powder, adhered with a resin, to make it able to hold an electrostatic charge, and absorb toner, to form an image and allow the evaporation of toner dispersants. Users of electrofax machines purchased paper with the coating already applied.
Copiers typically feed paper from a roll, where it is given a staticelectric charge, after which it is exposed to light reflected from the original document, and focused through a lens; zinc oxide particles either preserve or discharge the electric charge, depending on the amount of light reaching them. After exposure, the paper is passed through a toner station: toner is typically carbon black suspended in an organic liquid known as a dispersant, then spread over the paper. Black toner particles adhere to areas on the paper that remain charged; discharged areas do not attract toner particles. A knife then cuts the paper to the proper length (typically letter or legal size). The subsequently independent sheet of paper then passes from the toner station, where excess dispersant is wiped off. Typically, the paper is finally sent to an output tray where any remaining dispersant evaporates, leaving copies with a faint "kerosene" odor.
In printers and plotters, paper is typically electrostatically charged by passing it over a bar containing hundreds or thousands of charging contacts. As paper passes over it, an image is formed by either applying or removing a charge from each individual contact. The result is a grid of charged dots on the paper. Toner is then applied as described above.
In the early 1950s, this technology was first developed at RCA (Radio Corporation of America). Subsequently, many office machine companies, including SCM (Smith Corona Marchant), Savin, etc., introduced copiers that utilized this technology. Versatec was a brand of computer printers and plotters using this process; electrostatic printers like the Versatec were important stepping-stones to later laser printers. Programs like vtroff, by Tom Ferrin at UCSF, consequently justified early more expensive laser printers.
Copying machines using electrofax technology were common from the 1960s through the 1980s. They were less expensive to manufacture than xerographic copiers, although the paper was slightly more costly than the plain paper used by xerography. Electrofax fell out of favor when other copier technologies could produce markedly better quality copies at less expense. By comparison, electrofax suffered a number of drawbacks, including: weak blacks in the image (most machines could only produce a dark gray), dampness and odor of the copies, the need for special paper, and multiple-bottle liquid toner replacement. Similarly, the need for electrofax based printers & plotters faded, as laser printers became cheaper, followed by inkjet printers.
In computing, a printer is a peripheral machine which makes a persistent representation of graphics or text, usually on paper. While most output is human-readable, bar code printers are an example of an expanded use for printers. Different types of printers include 3D printers, inkjet printers, laser printers, and thermal printers.
Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The earliest known form of printing as applied to paper was woodblock printing, which appeared in China before 220 AD for cloth printing. However, it would not be applied to paper until the seventh century. Later developments in printing technology include the movable type invented by Bi Sheng around 1040 AD and the printing press invented by Johannes Gutenberg in the 15th century. The technology of printing played a key role in the development of the Renaissance and the Scientific Revolution and laid the material basis for the modern knowledge-based economy and the spread of learning to the masses.
Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a "drum" to define a differentially charged image. The drum then selectively collects electrically charged powdered ink (toner), and transfers the image to paper, which is then heated to permanently fuse the text, imagery, or both, to the paper. As with digital photocopiers, laser printers employ a xerographic printing process. Laser printing differs from traditional xerography as implemented in analog photocopiers in that in the latter, the image is formed by reflecting light off an existing document onto the exposed drum.
Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensive consumer models to expensive professional machines. By 2019, laser printers outsold inkjet printers by nearly a 2:1 ratio, 9.6% vs 5.1% of all computer peripherals.
The triboelectric effect is a type of contact electrification on which certain materials become electrically charged after they are separated from a different material with which they were in contact. Rubbing the two materials with each other increases the contact between their surfaces, and hence the triboelectric effect. Rubbing glass with fur for example, or a plastic comb through the hair, can build up triboelectricity. Most everyday static electricity is triboelectric. The polarity and strength of the charges produced differ according to the materials, surface roughness, temperature, strain, and other properties.
A blueprint is a reproduction of a technical drawing or engineering drawing using a contact print process on light-sensitive sheets. Introduced by Sir John Herschel in 1842, the process allowed rapid and accurate production of an unlimited number of copies. It was widely used for over a century for the reproduction of specification drawings used in construction and industry. The blueprint process was characterized by white lines on a blue background, a negative of the original. The process was not able to reproduce color or shades of grey.
A spirit duplicator is a printing method invented in 1923 by Wilhelm Ritzerfeld that was commonly used for much of the rest of the 20th century. The term "spirit duplicator" refers to the alcohols that were a major component of the solvents used as "inks" in these machines. The device coexisted alongside the mimeograph.
Xerography is a dry photocopying technique. Originally called electrophotography, it was renamed xerography—from the Greek: [n] roots ξηρόςxeros, meaning "dry" and -γραφία-graphia, meaning "writing"—to emphasize that unlike reproduction techniques then in use such as cyanotype, the process of xerography used no liquid chemicals.
Toner is a powder mixture used in laser printers and photocopiers to form the printed text and images on paper, in general through a toner cartridge. Mostly granulated plastic, early mixtures added only carbon powder and iron oxide, however, mixtures have since been developed containing polypropylene, fumed silica, and various minerals for triboelectrification. Toner using plant-derived plastic also exists as an alternative to petroleum plastic. Toner particles are melted by the heat of the fuser, and are thus bonded to the paper.
In electronics, electrical breakdown or dielectric breakdown is a process that occurs when an electrically insulating material, subjected to a high enough voltage, suddenly becomes a conductor and current flows through it. All insulating materials undergo breakdown when the electric field caused by an applied voltage exceeds the material's dielectric strength. The voltage at which a given insulating object becomes conductive is called its breakdown voltage and, in addition to its dielectric strength, depends on its size and shape, and the location on the object at which the voltage is applied. Under sufficient electrical potential, electrical breakdown can occur within solids, liquids, or gases. However, the specific breakdown mechanisms are different for each kind of dielectric medium.
An electrostatic precipitator (ESP) is a filterless device that removes fine particles, such as dust and smoke, from a flowing gas using the force of an induced electrostatic charge minimally impeding the flow of gases through the unit.
Powder coating is a type of coating that is applied as a free-flowing, dry powder. Unlike conventional liquid paint which is delivered via an evaporating solvent, powder coating is typically applied electrostatically and then cured under heat or with ultraviolet light. The powder may be a thermoplastic or a thermoset polymer. It is usually used to create a hard finish that is tougher than conventional paint. Powder coating is mainly used for coating of metals, such as household appliances, aluminium extrusions, drum hardware, automobiles, and bicycle frames. Advancements in powder coating technology like UV curable powder coatings allow for other materials such as plastics, composites, carbon fiber, and MDF to be powder coated due to the minimum heat and oven dwell time required to process these components.
Savin was incorporated in 1959 by Max M. and Robert K. Low, and the company was named after Max Low's son-in-law, Robert S. Savin. The firm was run by Low's son, Robert K. Low and E. Paul Charlap. It was known primarily for its unusual line of liquid-toner photocopiers, which set it apart from other companies that manufactured dry-toner equipment such as Konica, Xerox, Canon, Sharp, and Kodak.
Toner refilling is the practice of refilling empty laser printer toner cartridges with new toner powder. This enables the cartridge to be reused, saving the cost of a complete new cartridge and the impact of the waste and disposal of the old one.
A photocopier is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers use a technology called xerography, a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles onto paper in the form of an image. The toner is then fused onto the paper using heat, pressure, or a combination of both. Copiers can also use other technologies, such as inkjet, but xerography is standard for office copying.
A toner cartridge, also called laser toner, is the consumable component of a laser printer. Toner cartridges contain toner powder, a fine, dry mixture of plastic particles, carbon, and black or other coloring agents that make the actual image on the paper. The toner is transferred to paper via an electrostatically charged drum unit, and fused onto the paper by heated rollers during the printing process. It will not stain like ink cartridges, but it can get messy if handled improperly.
A contract proof usually serves as an agreement between customer and printer and as a color reference guide for adjusting the press before the final press run. Most contract proofs are a prepress proof.
Katun is a supplier of OEM-compatible imaging consumables and supplies for office equipment.
An electrostatic plotter is a type of plotter that draws images on paper with an electrostatic process. They are most frequently used for Computer-Aided Engineering (CAE), producing raster images via either a Liquid Toner or a Dry Toner model.
Photoconductive polymers absorb electromagnetic radiation and produce an increase of electrical conductivity. Photoconductive polymers have been used in a wide variety of technical applications such as Xerography (electrophotography) and laser printing. Electrical conductivity is usually very small in organic compounds. Conductive polymers usually have large electrical conductivity. Photoconductive polymer is a smart material based on conductive polymer, and the electrical conductivity can be controlled by the amount of radiation.
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