792:
into a waste toner compartment for later disposal; however, in some systems, it is routed back into the developer unit for reuse. This process, known as toner reclaim, is much more economical, but can possibly lead to a reduced overall toner efficiency through a process known as 'toner polluting' whereby concentration levels of toner/developer having poor electrostatic properties are permitted to build up in the developer unit, reducing the overall efficiency of the toner in the system.
54:
796:
developing system, developed by KIP from an abandoned line of research by Xerox, completely replaces magnetic toner manipulation and the cleaning system, with a series of computer-controlled, varying biases. The toner is printed directly onto the drum, by direct contact with a rubber developing roller which, by reversing the bias, removes all the unwanted toner and returns it to the developer unit for reuse.
723:
the moving drum or belt, fast enough to render a perfect latent image. Where there is text or image on the document, the corresponding area of the drum will remain unlit. Where there is no image the drum will be illuminated and the charge will be dissipated. The charge that remains on the drum after this exposure is a 'latent' image and is a negative of the original document.
783:
were trays covered in cotton gauze sprinkled with a volatile liquid, such as ether. When the transferred image was brought into proximity with the vapor from the evaporating liquid, the result was a perfectly fixed copy without any of the distortion or toner migration which can occur with the other methods. This method is no longer used due to emissions of fumes.
639:" powder). Photoconductors using organic compounds are electrochemically charged vice versa to the preceding system in order to exploit their native properties in printing. Organic photoconductors are now preferred because they can be deposited on a flexible, oval or triangular, belt instead of a round drum, facilitating significantly smaller device build size.
742:
In high-volume copiers, the drum is presented with a slowly turbulent mixture of toner particles and larger, iron, reusable carrier particles. Toner is a powder; its early form was carbon powder, then melt-mixed with a polymer. The carrier particles have a coating which, during agitation, generates a
726:
Whether in a scanning or a stationary optical system, combinations of lenses and mirrors are used to project the original image on the platen (scanning surface) onto the photoconductor. Additional lenses, with different focal lengths or zooming lenses are utilized to enlarge or reduce the image; the
722:
to be copied is illuminated by flash lamps on the platen and either passed over a lens or scanned by a moving light and lens, such that its image is projected onto and synchronized with the moving drum surface. Alternatively, the image may be exposed using a xenon strobe illuminating the surface of
925:
Pai, Damodar M.; Melnyk, Andrew R.; Weiss, David S.; Hann, Richard; Crooks, Walter; Pennington, Keith S.; Lee, Francis C.; Jaeger, C. Wayne; Titterington, Don R.; Lutz, Walter; Bräuninger, Arno; De
Brabandere, Luc; Claes, Frans; De Keyzer, Rene; Janssens, Wilhelmus; Potts, Rod. "Imaging Technology,
791:
The drum, having already been partially discharged during detack, is further discharged by light. Any remaining toner, that did not transfer in step 6, is removed from the drum surface by a rotating brush under suction, or a squeegee known as the cleaning blade. This 'waste' toner usually is routed
782:
The toner image is permanently fixed to the paper using either a heat and pressure mechanism (hot roll fuser) or a radiant fusing technology (oven fuser) to melt and bond the toner particles into the medium (usually paper) being printed. There also used to be available "offline" vapor fusers. These
764:
Paper is passed between the drum and the transfer corona, which has a polarity that is the opposite of the charge on the toner. The toner image is transferred from the drum to the paper by a combination of pressure and electrostatic attraction. On many color and high-speed machines, it is common to
747:
charge (a form of static electricity), which attracts a coating of toner particles. In addition, the mix is manipulated with a magnetic roller to present to the surface of the drum or belt a brush of toner. By contact with the carrier each neutral toner particle has an electric charge of polarity
751:
Where a negative image is required, as when printing from a microform negative, then the toner has the same polarity as the corona in step 1. Electrostatic lines of force drive the toner particles away from the latent image towards the uncharged area, which is the area exposed from the negative.
709:
The polarity is chosen to suit the positive or negative process. Positive process is used for producing black on white copies. Negative process is used for producing black on white from negative originals (mainly microfilm) and all digital printing and copying. This is to economize on the use of
795:
Some systems have abandoned the separate developer (carrier). These systems, known as monocomponent, operate as above, but use either a magnetic toner or fusible developer. There is no need to replace worn-out developer, as the user effectively replaces it along with the toner. An alternative
773:
Electric charges on the paper are partially neutralized by AC from a second corona, usually constructed in tandem with the transfer corona and immediately after it. As a result, the paper, complete with most (but not all) of the toner image, is separated from the drum or belt surface.
634:
sought to avoid Xerox's patents for selenium drums by developing organic photoconductors as an alternative to the selenium drum. In the original system, photocopiers that rely on silicon or selenium (and its alloys) are charged positively in use (hence work with negatively charged
748:
opposite to the charge of the latent image on the drum. The charge attracts toner to form a visible image on the drum. To control the amount of toner transferred, a bias voltage is applied to the developer roller to counteract the attraction between toner and latent image.
755:
Early color copiers and printers used multiple copy cycles for each page output, using colored filters and toners. Modern units use only a single scan to four separate, miniature process units, operating simultaneously, each with its own coronas, drum and developer unit.
576:
The first commercial use was hand processing of a flat photosensor (an electrostatic component that detects the presence of visible light) with a copy camera and a separate processing unit to produce offset lithographic plates. Today this technology is used in
656:
The steps of the process are described below as applied on a cylinder, as in a photocopier. Some variants are described within the text. Every step of the process has design variants. The physics of the xerographic process are discussed at length in a book.
891:
Xerography has been used by photographers internationally as a direct imaging photographic process, by book artists for publishing one-of-a-kind books or multiples, and by collaborating artists in portfolios such as those produced by the
677:
from a corona unit (Corotron), with output limited by a control grid or screen. This effect can also be achieved by using a contact roller with a charge applied to it. Essentially, a corona discharge is generated by a very thin wire
1106:
Baudelaire thought machines would be the death of art," New York artist Louise
Neaderland said this week during a chat at 1708 East Main . "On the other hand, if Leonardo da Vinci had had a photocopier, I think he would have used
730:
A drum is inferior to a belt in the sense that although it is simpler than a belt, it must be buffered gradually in parts rolling on the curved drum, while the flat belt efficiently uses one exposure to make a direct passage.
831:
can last as long as typewritten or handwritten documents on the same paper. However, xerographic copies are vulnerable to undesirable toner transfer if they are stored in direct contact or close proximity to
612:. A metal cylinder called the drum is mounted to rotate about a horizontal axis. The drum rotates at the speed of paper output. One revolution passes the drum surface through the steps described below.
734:
In a laser or LED printer, modulated light is projected onto the drum surface to create the latent image. The modulated light is used only to create the positive image, hence the term "blackwriting".
908:
at 1708 Gallery in
Richmond, Virginia, "She's living proof that, when a new technology begins to be mass-produced, artists will be curious enough—and imaginative enough—to explore its creative uses.
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rectifying (diode-causing) layer that minimizes current leakage, and a surface layer of silicon doped with oxygen or nitrogen; silicon nitride is a scuff-resistant material.
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to develop it as a commercial product. Before that year, Carlson had proposed his idea to more than a dozen companies, but none was interested. Haloid's president,
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in the untreated pulp; in the worst case, old copies can literally crumble into small particles when handled. High-quality xerographic copies on
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replace the transfer corona with one or more charged bias transfer rollers, which apply greater pressure and produce a higher quality image.
1104:
Proctor, Roy (April 14, 1980). "1708 provides a showcase for photocopier art". Richmond, Virginia: The
Richmond News Leader. p. A-44.
615:
The end-to-end dimension is the width of print to be produced plus a generous tolerance. The drums in the copiers originally developed by
844:. In extreme cases, the ink toner will stick directly to the binder cover, pulling away from the paper copy and rendering it illegible.
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will be repelled and pushed away onto the conductor. The conductor is set on top of a conducting surface, kept at ground potential.
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adapted xerography to eliminate the hand-inking stage in the animation process by printing the animator's drawings directly to the
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630:. Amorphous selenium will hold an electrostatic charge in darkness and will conduct away such a charge under light. In the 1970s,
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durability, depending on the quality of the paper used. If low-quality paper is used, it can yellow and degrade due to residual
534:, saw the promise of Carlson's invention, and saw to it that Haloid diligently worked to produce a working commercial product.
1153:
Eichhorn, Kate (2016). Adjusted Margin: Xerography, Art, and
Activism in the Late Twentieth Century. Cambridge: The MIT Press.
531:
861:
1128:
Copies in
Seconds: How a Lone Inventor and an Unknown Company Created the Biggest Communication Breakthrough Since Gutenberg
871:, released two years earlier. At first, only black lines were possible, but in 1977, gray lines were introduced and used in
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The development of xerography has led to new technologies that have the potential to eventually eradicate traditional
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in 1778. Carlson's original process was cumbersome, requiring several manual processing steps with flat plates.
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It was almost 18 years before a fully automated process was developed, the key breakthrough being the use of a
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By using a cylinder to carry the photosensor, automatic processing was enabled. In 1960, the automatic
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Draw the
Lightning Down: Benjamin Franklin and Electrical Technology in the Age of Enlightenment
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Xerographic documents (and the closely related laser printer printouts) can have excellent
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technique. Originally called electrophotography, it was renamed xerography—from the Greek
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is placed on the wire, which will ionize the space between the wire and conductor, so
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instead of a flat plate. This resulted in the first commercial automatic copier, the
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and in the 1980s, colored lines were introduced and used in animated features like
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was created and many millions have been built since. The same process is used in
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1149:. Springer Series in Electrophysics. Vol. 14. Berlin: Springer-Verlag.
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sandwich structure with a hydrogen-doped silicon light-chargeable layer, a
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30:"Electrophotography" redirects here. For the photographic technique, see
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laser light by the "blackwriting" or "write to black" exposure method.
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626:(more recently ceramic or organic photoconductor or OPC), applied by
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Schiffer, Michael B.; Hollenback, Kacy L.; Bell, Carrie L. (2003).
698: inch (6.35 to 12.7 mm) away from the photoconductor. A
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1083:(1st ed.). Montréal: Éditions de la Nouvelle barre du jour.
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Médium, photocopie : copigraphie canadienne et allemande
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is uniformly distributed over the surface of the drum by a
859:. The first animated feature film to use this process was
987:. Berkeley: University of California Press. pp.
865:(1961), although the technique was already tested in
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scanning speed must adapt to elements or reductions.
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article on the history and technology of xerography
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The
Physics and Technology of Xerographic Processes
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900:. Art critic Roy Proctor said of artist/curator
896:founded by American printmaker and book artist,
803:machines. These new machines that print in full
929:Ullmann's Encyclopedia of Industrial Chemistry
926:2. Copying and Nonimpact Printing Processes".
483:Xerography was invented by American physicist
412:
8:
619:were manufactured with a surface coating of
589:which are slowly replacing many traditional
593:in the printing industry for shorter runs.
471:, the process of xerography used no liquid
1147:Electrophotography and Development Physics
642:Laser printer photo drums are made with a
526:In 1946, Carlson signed an agreement with
487:, based significantly on contributions by
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932:. Weinheim: Wiley-VCH. pp. 1–53.
495:. Carlson applied for and was awarded
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1051:vol. 13, p. 394, 10th edition, 2007
1023:vol. 13, p. 395, 10th edition, 2007
1130:. New York: Simon & Schuster.
25:
1171:"Static Pops Pictures On Paper"
1062:"Xerography and animated films"
556:Xerography is now used in most
862:One Hundred and One Dalmatians
504:Carlson's innovation combined
1:
938:10.1002/14356007.o13_o08.pub2
604:printers and computer output
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769:Step 5. Separation or detack
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1079:Georg Mühleck, ed. (1987).
528:Haloid Photographic Company
521:Georg Christoph Lichtenberg
1229:
1019:"Photocopying processes".
962:"Definition of Xerography"
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443:
29:
27:Dry photocopying technique
1047:Photocopying processes".
366:Thermal-transfer printing
778:Step 6. Fixing or fusing
241:Photostat and rectigraph
836:, which are present in
40:Part of a series on the
1145:Schein, L. B. (1988).
898:Louise Odes Neaderland
91:Intaglio (printmaking)
498:U.S. patent 2,297,691
211:Hot metal typesetting
1003:electrophorus volta.
549:, being released by
519:process invented by
501:on October 6, 1942.
454:, meaning "dry" and
231:Daisy wheel printing
1208:American inventions
1198:Non-impact printing
738:Step 3. Development
271:Dot matrix printing
46:History of printing
32:Kirlian photography
1193:1942 introductions
880:The Secret of NIMH
579:photocopy machines
356:Solid ink printing
71:Woodblock printing
18:Electrophotography
902:Louise Neaderland
848:Uses in animation
838:looseleaf binders
628:vacuum deposition
617:Xerox Corporation
541:drum coated with
512:, unlike the dry
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261:Spirit duplicator
171:Chromolithography
16:(Redirected from
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525:
503:
482:
436:photocopying
431:
430:
280:
181:Rotary press
81:Movable type
1124:Owen, David
887:Uses in art
598:photocopier
539:cylindrical
510:photography
493:Pál Selényi
376:3D printing
349: 1972
161:Lithography
124: 1515
109: 1440
1187:Categories
912:References
840:made with
815:Durability
553:in 1960.
491:physicist
432:Xerography
281:Xerography
221:Mimeograph
191:Hectograph
63:Techniques
1213:Xerox art
853:Ub Iwerks
720:microform
704:electrons
621:amorphous
602:microform
547:Xerox 914
489:Hungarian
473:chemicals
469:cyanotype
434:is a dry
131:Mezzotint
1126:(2004).
821:archival
624:selenium
543:selenium
517:printing
151:Aquatint
693:⁄
683:⁄
572:Process
479:History
116:Etching
1157:
1134:
1087:
995:
944:
809:Xeikon
585:, and
991:–44.
671:volts
644:doped
637:toner
606:laser
562:laser
451:xeros
445:ξηρός
440:roots
1155:ISBN
1132:ISBN
1085:ISBN
993:ISBN
942:ISBN
825:acid
805:CMYK
564:and
390:1991
380:1986
370:1981
360:1972
335:1969
325:1957
315:1950
305:1949
295:1940
285:1938
275:1925
265:1923
255:1911
245:1907
235:1889
225:1885
215:1884
205:1875
195:1860
185:1843
175:1837
165:1796
155:1772
145:1690
135:1642
95:1430
85:1040
1107:it.
989:242
934:doi
842:PVC
688:to
665:An
608:or
75:200
1189::
1040:^
1010:^
1001:.
964:.
940:.
883:.
581:,
568:.
475:.
346:c.
121:c.
106:c.
1140:.
1093:.
968:.
950:.
936::
695:2
691:1
685:4
681:1
635:"
420:e
413:t
406:v
34:.
20:)
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