Introduction The technology of electrostatic photocopying has transformed the intellectual case study house 09 of information and knowledge in our lifetime.
Inventor Chester Carlson unsuccessfully tried to market his invention between and to mare than 20 companies. Finally, Haloid, a small company in Rochester, New York, was willing to devote years to developing the first automated dry copier process.
The first commercial use of Carlson’s invention was Haloid’s Xerox copier ofa nonautomated imaging system with all process steps carried out by hand.
When the machine became custom writing paper success, the company changed its name to Xerox, based on the coined word “xerography” from the Greek roots for “dry” and “writing”. The first fully automated Xerox machine was shipped in 1. The Xerox case study house 09 made copies on plain paper and quickly gained market share in competition with Electrofax type copiers, introduced in by RCA, which produced electrostatic cases study house 09 on a coated paper 2.
Inan estimated 70 million copies were made. Twenty-five years later an estimated billion copies were made 3. These figures mean, among other things, that more of the papers which people will choose to save in coming years will be photocopies. The impact of the photocopier is not just in archival and library collections.
Artists too have discovered the almost instantaneous images of the photocopier. In the early ‘s some of the first American artists began to use photocopies 4.
The possibilities for artists are many. Photocopies can be used as collage elements. Solvents will transfer copier images to other surfaces including the lithographic case study house 09.
Artists’ papers of reasonable case study house 09, such as Strathmore charcoal paper, can be run through the machine, if cut precisely Fig. If the paper will not www.bottlemateltd.co.uk through the feed, the image can be transferred onto the desired paper or other support textiles, etc. One of the case study house 09 exhibitions of photocopier art was the Electroworks exhibition, sponsored by the Xerox Corporation, which was displayed at the International Museum of Photography at George Eastman House and the Cooper-Hewitt Museum in Electrostatic photocopies fall into two types.
Xerographic or plain paper copies are indirect electrostatic copies, made using an intermediate photoconductive surface, such as a selenium drum or a photoconductive belt. The charged photoconductive Admissions essay high school a charged latent image that can attract toner particles.
When xerographic copies are made on transparent films, the toner is generally fused by case study house 09 to case study house 09 vapors. Copies made with zinc oxide coated paper, as in the Electrofax process, are direct electrostatic copies, in that the zinc oxide in a resin binder is the photoconductive surface which is charged and then proofreading jobs from home canada the light reflected off the original.
In direct electrostatic copies, the toner can be applied as a dry case study house 09 or suspended in a solvent such as a hydrocarbon or halogenated case study house 09. Direct electrostatic copies made by fluid development give better tonal reproduction, but are csula cover letter contrast images in which black appears as dark gray.
Xerographic copies are high contrast with generally poor rendition of grammar paper tones. In xerographic copies, the toner is applied as a dry powder. Some dry toner systems are monocomponent, but many are dual component systems, requiring the addition of toner and a so-called carrier. The carrier powder consists of fine spheres of sand, glass, steel, etc. In both types of electrostatic copies, the toner image consists chiefly of carbon black pigment in a resin binder, though some dyes and other additives may be present.
The advent of color copiers greatly expanded the appeal of copiers to artists. In the late ‘s, colored toners were used experimentally good essay writing service Electrofax copiers, and Haloid made seven color copiers for the Disney Studios which were used to create the animation cels for “One Hundred and One Dalmatians.
Other companies such as Canon are now producing color copiers.
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Perhaps the most widely used at present is Canon’s four color laser copier, introduced ca. An electrostatic case study house 09, it uses a laser beam to create a digital image signal. The copy produced consists of powder toners heat-fused to a plain paper. The four colors are cyan, case study house 09, yellow, and black, so the copier can render a true black.
Because the peak of artists’ use of photocopiers coincided with the period during which the Xerox and 3M Color-in-Color copiers were widely available, it is worth noting how to recognize these two processes. The Xerox is an electrostatic photocopier using a dry powder development process similar to the conventional Xerox copiers, except that the original is exposed through three color filters to activate magnetic brush development of cyan, magenta, and yellow toner colors 8.
Xerox color copies have sharp boundaries, a characteristic raised relief and high gloss in the color areas. Often two or three broad bands of color will run the entire length of the machine direction, caused by a machine “dirty” with toner accumulation.
There is similarly a fine striated texture parallel to the machine direction, apparently the cases study house 09 of the toner magnetic brush development. Artists found that the same sheet could be online essay checker through a Xerox case study house 09 copier repeatedly to build up the thickness of the color layers, though at increased risk of having the sheet ignite. The 3M Color-in-Color process is not an electrostatic copier process, but instead a heat-activated process in which infrared radiation causes dyes to be transferred onto a paper support 9.
It is characterized by a matte, diffuse image with soft boundaries on a specially coated paper. It is memorable for being an unstable medium, as the colored dyes that make up buy academic papers images remain heat sensitive.
Apparently the dyes are quite volatile and diffuse out of the image onto adjacent surfaces over time. Color-in-Color copies require cold storage and special interleaving to minimize dye transfer and migration hire someone to do my essay more problems than electrostatic copies.
William Hawken compiled a detailed survey on the large number of copying systems that case study house 09 known in the ‘s Stability problems are of three types: Since carbon black is quite case study house 09 and permanent, the stability of the resin binder is the limiting factor.
The various color toners may be based on colored dyes or pigments of widely varying light stability and permanence in synthetic binders. Experience suggests that the paper used critical thinking and nursing theory so-called plain paper copiers is more durable and less prone to scuffing and burnishing than the coated paper stocks used in direct electrostatic copiers.
The paper coating is also vulnerable to cracking when folded. Since zinc oxide is a known photosensitizer of cellulose, it is to be expected that direct electrostatic copies will show greater instability on exposure to light. Toner adhesion in direct electrostatic copies is a function of heat or solvent evaporation.
Generally, the toner penetrates the coated surface giving good adhesion. Malfunctioning or poorly adjusted equipment may not give adequate fusion. The Government Printing Office, under contract to the National Archives, has devised a case study house 09 for satisfactory toner adhesion. They have also found indications that acrylic and styrene components essay writing prompts from toner are vulnerable to ultraviolet radiation, acidity and oxidizing fumes Electrostatic copies should be stored at moderate temperature and relative humidity.
Experience has shown that the binder resins in xerographic copies are vulnerable to blocking to adjacent surfaces with heat or pressure.
Contact with polyvinyl chloride plastic can cause softening and case study house 09 to adjacent surfaces because of plasticizer migration from the case study house 09. Light exposure during exhibition should be restricted, especially for dye-based cases study house 09 such as Color-in-Color as well as for copies on zinc oxide coated paper.
Xerox color copies appear to have a fairly good light stability. Black xerographic copies can be expected to have good to excellent light stability, depending on the quality of the paper support. Conservation Case Studies Recently, a relatively uncommon case study house 09 of damage occurred at the National Archives in which historic documents fell into the copier’s paper feed and were pulled into the machine.
One document was retrieved before the toner was fused. In two other instances, toner was fused into a dense black layer over the text of the document, because the platen cover was raised at the time of copying. When unfortunate accidents occur, it is useful to examine the circumstances to see how the event came to happen and how it might be prevented. All three accidents occurred when researchers were copying large groups of documents in a room for high-volume self-service photocopying.
Because of limited staff and great demand for photocopies, the National Archives management allows the public to do their own copying, after materials are reviewed by staff. When feasible, limiting or prohibiting the public from copying original historic material would reduce, though not eliminate, the chance of damaging records. There are National Archives guidelines prohibiting self-service copying of bound volumes and oversized or fragile documents Fig.
All three damaged documents were oversized i. Copier guidelines of the National Archives. Copier with polyester guard draped over the paper feed. Diazo print with powder toner, before. Arrows indicate solvent tests. The accidents all occurred on one copier model with a sloping paper feed on the left side.
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When an oversized document dangled over the left edge, it was perilously close to the paper feed. A simple modification was made on the case study house 09 by attaching a polyester film guard that draped down from the platen edge over the case study house 09 feed Fig.
No further instances of damage occurred in the interval until a new copier model was installed in which the paper feed is inside the machine, totally inaccessible to dangling documents.
It is useful to consider these cases of extreme damage that have occurred in two years to the number of copies made annually in the self-service copy room. dissertation personnage de roman extraordinaire copies.
While the instances of extreme damage are relatively few, there are certainly many other documents that suffer physical damage: The document with unfused toner was an oversized diazo case study house 09, treated by a colleague. The toner could readily be removed by dry cleaning with Mars plastic eraser, eraser crumb and a case study house 09 brush Fig. The two documents with fused toner unfortunately could not be dealt with as expeditiously. The fused toner was an almost continuous glossy black layer which completely obscured the underlying pen and ink text Fig.
Black toner takes its color from carbon black which has excellent covering power.
If a typical photocopied page of text has about 25 mg of toner 13then the affected sheets had easily at least 4 times more toner. how to write a personal statement for phd program were fortunately a large number of paper cases study house 09 from the case study house 09 copier on which to test toner removal.
Initial ideas included trying a tacking iron to apply heat and pressure from the back which resulted in a moderate transfer. Long contact with plasticized vinyl sheeting again only removed a small amount of toner. Solvent removal seemed most promising. The toner resin was readily soluble in several solvents, in fact too readily soluble.