RISOGRAPHY
Risograph is a high-speed digital printing system manufactured by the Riso Kagaku Corporation and designed mainly for high-volume photocopying
and printing. Increasingly, Risograph machines have been commonly
referred to as a RISO Printer-Duplicator, due to their common usage as a
network printer as well as a stand-alone duplicator.
When printing or copying multiple quantities (generally more than 20)
of the same original, it is typically far less expensive per page than a
conventional photocopier, laser printer, or inkjet printer. Printing
historian Rick O'Connor has debated that the original, and thus correct,
name for the device is RISSO and not RISO. This debate spawns from the
notion that an extra 'S' is added because the inventor's wife found it
more pleasing to the ears.
How a Risograph works
The underlying technology is very similar to a mimeograph. It brings together several processes which were previously carried out manually, for example using the Riso Print Gocco system or the Gestetner system.
The original is scanned through the machine and a master is created,
by means of tiny heat spots on a thermal plate burning voids
(corresponding to image areas) in a master sheet. This master is then
wrapped around a drum and ink is forced through the voids in the master.
The paper runs flat through the machine while the drum rotates at high
speed to create each image on the paper.
This simple technology is highly reliable compared to a standard
photocopier and can achieve both very high speeds (typically 130 pages
per minute) and very low costs. A good lifespan for a risograph might involve making 100,000 masters and 5,000,000 copies.
The key master-making thermal head component is manufactured by Toshiba. Similar machines to Risographs are manufactured by Ricoh, Gestetner, Rex Rotary and Nashuatec. All these other brands are now owned by Ricoh.
Because the process involves real ink - like offset printing - and
does not require heat to fix the image on the paper - like a photocopier
or laser printer - the output from a risograph can be treated like any
printed material. This means that sheets which have been through a
risograph may happily go through a laser printer afterwards and
vice-versa.
For schools, clubs, colleges, political campaigns and other short run
print jobs, the Risograph bridges the gap between a standard
photocopier (which is cheaper up to about 50 copies) and using a
commercial printer (cheaper over about 10,000 copies).
Risographs have typically had interchangeable colour inks and drums
allowing for printing in different colours or using spot colour in one
print job. The Riso MZ series models have two ink drums allowing two
colours to be printed in one pass.
MIMEOGRAPHY
http://en.wikipedia.org/wiki/Mimeograph
The stencil duplicator or mimeograph machine (often abbreviated to mimeo) is a low-cost printing press that works by forcing ink through a stencil onto paper.
Along with spirit duplicators and hectographs,
mimeographs were for many decades used to print short-run office work,
classroom materials, and church bulletins. They also were critical to
the development of early fanzines because their low cost and availability enabled publication of amateur writings. These technologies began to be supplanted by photocopying and cheap offset printing in the late 1960s.
Although in mid-range quantities, mimeographs remain more economical
and energy-efficient, easier-to-use photocopying and offset printing
have replaced mimeography almost entirely in developed countries. Mimeograph machines continue to be used in developing countries because it is a simple, cheap, and robust technology. Many mimeographs can be hand-cranked, and thus require no electricity.
Origins
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
The image transfer medium is a stencil made from waxed mulberry paper. This flexible waxed sheet is backed by a sheet of stiff card stock, with the sheets bound at the top.
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
(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.
Uses and art
Mimeographs and the closely related but distinctly different spirit duplicator
process were both used extensively in schools to copy homework
assignments and tests. They were also commonly used for low-budget
amateur publishing, including club newsletters and church bulletins. They were especially popular with science fiction fans, who used them extensively in the production of fanzines in the middle 20th century, before photocopying became inexpensive.
Letters and typographical symbols were sometimes used to create illustrations, in a precursor to ASCII art.
Because changing ink color in a mimeograph could be a laborious
process, involving extensively cleaning the machine or, on newer models,
replacing the drum or rollers, and then running the paper through the
machine a second time, some fanzine publishers experimented with
techniques for painting several colors on the pad, notably Shelby Vick, who created a kind of plaid "Vicolor."
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