Mimeograph
Thomas Edison received US patent 180,857 for "Autographic Printing" on August 8, 1876. The patent covered the electric pen, used for making the stencil, and the flatbed duplicating press. In 1880 Edison obtained a further patent, US 224,665: "Method of Preparing Autographic Stencils for Printing", which covered the making of stencils using a file plate, a grooved metal plate on which the stencil was placed which perforated the stencil when written on with a blunt metal stylus.The word "mimeograph" was first used by Albert Blake Dick when he licensed Edison's patents in 1887.
Dick received Trademark Registration no. 0356815 for the term "Mimeograph" in the U.S. Patent Office. It is currently listed as a dead entry, but shows the A.B. Dick Company of Chicago as the owner of the name.
Over time, the term became generic and is now an example of a genericized trademark.("Roneograph," also "Roneo machine," was another trademark used for mimeograph machines, the name being a contraction of Rotary Neostyle)
Others who worked concurrently on the development of stencil duplicating were Eugenio de Zaccato and David Gestetner, both in Britain. In Britain the machines were most often referred to as "duplicators", though the predominance of Gestetner and Roneo in the UK market meant that some people referred to the machine by one of those two manufacturers' names.
In 1891, Gestetner patented his Automatic Cyclostyle. This was one of the first rotary machines that retained the flatbed, which passed back and forth under inked rollers. This invention provided for more automated, faster reproductions since the pages were produced and moved by rollers instead of pressing one single sheet at a time.
By 1900, two primary types of mimeographs had come into use: a single-drum machine and a dual drum machine. The single-drum machine used a single drum for ink transfer to the stencil and the dual-drum machine used two drums and silk-screens to transfer the ink to the stencils. The single drum (example Roneo) machine could be easily used for multi color work by changing the drum - each of which contained ink of a different color. This was spot color for mastheads. Colors could not be mixed.
The mimeograph became popular because it was much cheaper than traditional print - there was no typesetting or skilled labor involved. One individual with a typewriter and the necessary equipment essentially became his own printing factory, which allowed for greater circulation of printed material.
Mimeography Process
Once prepared, the stencil is wrapped around the ink-filled drum of the rotary machine. When a blank sheet of paper is drawn between the rotating drum and a pressure roller, ink is forced through the holes on the stencil onto the paper. Early flatbed machines used a kind of squeegee.
Preparing stencils
For printed copy, a stencil assemblage is placed in a typewriter. The typewriter ribbon has to be disabled so that the bare, sharp type element strikes the stencil directly. The impact of the type element displaces the wax, making the tissue paper permeable to the oil-based ink. This is called "cutting a stencil."
A variety of specialized styluses were used on the stencil to render lettering, illustrations, or other artistic features by hand against a textured plastic backing plate.
Mistakes can be corrected by brushing them out with a specially-formulated correction fluid, and retyping once it has dried. ("Obliterine" was a popular brand of correction fluid in Australia and the United Kingdom.)
Stencils were also made with a thermal process, an infrared method similar to that used by early photocopiers. The common machine was called a Thermofax.
Another device, called an electrostencil machine, sometimes was used to make mimeo stencils from a typed or printed original. It worked by scanning the original on a rotating drum with a moving optical head and burning through the blank stencil with an electric spark in the places where the optical head detected ink. It was slow and filled the air with ozone and text produced from electrostencils was of lower resolution than that produced by typed stencils, although the process was good for reproducing illustrations. A skilled mimeo operator using an electrostencil and a very coarse halftone screen could make acceptable printed copies of a photograph.
During the declining years of the mimeograph, some people made stencils with early computers and dot-matrix impact printers.
Limitations
Unlike spirit duplicators (Ditto Machines) (where the only ink available is depleted from the master image), mimeograph technology works by forcing a replenishable supply of ink through the stencil master. In theory, the mimeograph process could be continued indefinitely, especially if a durable stencil master were used (e.g. a thin metal foil). In practice, most low-cost mimeo stencils gradually wear out over the course of producing several hundred copies. Typically the stencil deteriorates gradually, producing a characteristic degraded image quality until the stencil tears, abruptly ending the print run. If further copies are desired at this point, there is no choice but to make up another stencil from scratch.
Often, the stencil material covering the interiors of closed letterforms (e.g. "a", "b", "d", "e", "g", etc.) would fall away during continued printing, causing ink-filled letters in the resulting copies. The stencil would gradually stretch, starting near the top where the mechanical forces were greatest, causing a characteristic "mid-line sag" in the textual lines of the copies, that would progress until the stencil failed completely. The Gestetner Company (and others) devised various methods to make mimeo stencils last longer in use.
Compared to spirit duplication, mimeography produced a darker, more legible image. Spirit duplicated images were usually tinted a light purple or lavender. which gradually became lighter and fainter in color over the course of some dozens of copies. Mimeography was often considered "the next step up" in quality, capable of producing hundreds of copies. Print runs beyond that level were usually produced by professional printers, or as the technology became available, xerographic copiers.
Contemporary use
Gestetner, Risograph, and other companies still make and sell highly automated mimeograph-like machines that are externally similar to photocopiers. The modern version of a mimeograph, called a digital duplicator, or copyprinter, contains a scanner, a thermal head for stencil cutting, and a large roll of stencil material entirely inside the unit. It makes the stencils and mounts and unmounts them from the print drum automatically, making it almost as easy to operate as a photocopier. The Risograph is the best known of these machines.
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Spirit duplicator
A spirit duplicator (also referred to as a Ditto machine in the United States or Banda machine in the United Kingdom) was a low-volume printing method used mainly by schools and churches. It was also used by members of science fiction fandom and early comic book fandom to produce fanzines. Sheets printed on such a machine were sometimes called ditto sheets, or just dittos in the U. S. (an example of a genericized trademark). The term "spirit duplicator" refers to the alcohols which were a major component of the solvents used as "inks" in these machines. They are sometimes confused with the mimeograph, which is actually a different technology.
History
The thermofax machine was introduced by 3M in the late 1960s and could make a spirit master from an ordinary typewritten or handwritten sheet. The resulting print quality was very poor but the machines were popular because of their convenience.
Spirit duplicator technology gradually fell into disuse starting in the 1970s after the availability of low-cost, high-volume xerographic copiers; by the mid 1990s, the use of the technology was rare. The technology remains useful where electrical power is unavailable or where the only remaining originals of legacy documents requiring duplication are in "spirit master" form.
Operation
There is no ink used in spirit duplication. As the paper moves through the printer, the solvent is spread across each sheet by an absorbent wick. When the solvent-impregnated paper comes into contact with the waxed original, it dissolves just enough of the pigmented wax to print the image onto the sheet as it goes under the printing drum.
Colors
The usual wax color was aniline purple, a cheap, durable pigment that provided good contrast, but masters were also manufactured in red, green, blue, black, and the hard-to-find orange, yellow, and brown. All except black reproduced in pastel shades: pink, mint, sky blue, etc. Ditto had the useful ability to print multiple colors in a single pass, which made it popular with cartoonists. Multi-colored designs could be made by swapping out the waxed second sheets; for instance, shading in only the red portion of an illustration while the top sheet was positioned over a red-waxed second sheet. This was possible because the pungent-smelling duplicating fluid (typically a 50/50 mix of isopropanol and methanol) was not ink, but a clear solvent.
Paper
This process worked best with cheap, lightweight paper stocks, but when the sheets of paper were impregnated with the solvent they could easily crease or crumple, jamming the machine. One well-made master could at most print about 500 copies before the pigment was exhausted and the print quality became illegibly faint. If fewer copies were required, the master could be removed from the printing drum and saved for future use.
Smell
The aroma of pages fresh off the duplicator combined with the cool touch from the evaporating alcohol was a memorable feature of school life for those who attended in the spirit duplicator era. A pop culture reference to this is to be found in the film Fast Times At Ridgemont High. At one point a teacher hands out a duplicated exam paper and every student in the class immediately lifts it to his or her nose and inhales.
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