The termphotocopying hazards brings to mind such common problems as thedifficulty of copying books without damage, high light and heatlevels at the copier platen, and everyday wear and tear on theoriginals being handled. Malfunctioning orpoorly adjusted equipment may not give adequate fusion. The resulting toner image is then transferred onto paperand fused with heat andor pressure. When the next treatment of thistype was planned, a plexi dome was placed over the suction table tocontain solvent vapors and immersion was carried out in polyestertrays on the top of the suction table. Xerographic orplain paper copies are indirect electrostatic copies, made using anintermediate photoconductive surface, such as a selenium drum or aphotoconductive belt Buy now Kodak Case Study
In fiscal year 1988, two photocopy machineswere in almost constant operation, making a total of 451,486 copies. Polymer 2 toner was based on a ratio of styrene to2-butylmethacrylate of 80 to 20 by weight (molecular weight ca28,000), plus 20 pentaerythritol tetrabenzoate as plasticizer, polymer 3 was based on a ratio of styrene to 1-butylmethacrylateof 58 to 42 (molecular weight ca 70,000), polymer 4 was based on a ratio of styrene to 1-butylmethacrylateto 65 to 35 (molecular weight of 70,000) plus 10 polyvinylbutyral, the chapter on polyvinyl acetals in skeists handbook ofadhesives lists a xerographic toner formulation patented by thehaloid corporation in 1956, containing a medium molecular weightpolyvinyl butyral and a phenol-formaldehyde resin (40) 25 butvarb-90 resin, 5o carbon black, 70 amberol f-71 Kodak Case Study Buy now
Anobvious but often unstated guideline is that some items simplycannot be photocopied safely and staff must exercise judgment andauthority in those cases. The document wasimmersed in a polyester tray of toluene for ca 5 seconds andimmediately transferred face down on the suction table. In the early days ofphotocopiers, the sensitizing light source was filtered green tomatch the optimal sensitivity of the photoconductive surface. On thefirst immersion, the release of toner in small swirls was notedbefore the document could be lifted out and over to the blottersurface. Malfunctioning orpoorly adjusted equipment may not give adequate fusion.
There isno description of where measurements were made within the room, soit is possible that the device was remote from the machines and theroom sufficiently large and well-ventilated so as to dilute ozone tobelow the limit of detection of 2-3 ppb Buy Kodak Case Study at a discount
Experience suggests that the paper used inso-called plain paper copiers is more durable and less prone toscuffing and burnishing than the coated paper stocks used in directelectrostatic copiers. One document wasretrieved before the toner was fused. The treatment was carried out under the plexi dome on the suctiontable with polyester trays of ethyl acetate for immersion. In examining the layers after treatment, one could see theextreme mobility of the toner components. A patented process has just been publishedthis year for a method using an unidentified proprietary solutionthat allows successful removal of toner in repulping during suction table work, a sheet of whatman filter paper laybeneath the document, and two layers of blotter under the filterpaper Buy Online Kodak Case Study
As glass transmits ultraviolet rays between 325 and 400nanometers, copiers with ultraviolet-producing lights such asfluorescent, tungsten halogen or xenon flash will expose documentsto some ultraviolet when an original item is liable to be copied repeatedly, a singlemaster copy can be used (and retained) to make further photocopies,in order to prevent wear and tear and excessive light exposure tothe original. Other colleagues at thenational archives have thoughtfully read and advised on this text. Inventor chester carlson unsuccessfully tried to markethis invention between 19 to mare than 20 companies. Torben bruun hansen and bente andersen,ozone and other air pollutants from photocopying machines, 26 Buy Kodak Case Study Online at a discount
Black tonertakes its color from carbon black which has excellent coveringpower. Despite the high mutagenic activityof nitro-containing chemicals, they are not considered to becarcinogenic. In two other instances, tonerwas fused into a dense black layer over the text of the document,because the platen cover was raised at the time of copying. Torben bruun hansen and bente andersen,ozone and other air pollutants from photocopying machines, 26. Appel,the oxidation of cellulose by ozone in small concentrations, 22 1952.
The concernabout high light and heat levels is tempered today by the knowledgethat the time of exposure is very brief, so that cumulative lightand heat are not great, as long as the item is not copied repeatedly Kodak Case Study For Sale
Somedry toner systems are monocomponent, but many are dual componentsystems, requiring the addition of toner and a so-called carrier. New york international museum of photography at georgeeastman house, 1979, p. The termphotocopying hazards brings to mind such common problems as thedifficulty of copying books without damage, high light and heatlevels at the copier platen, and everyday wear and tear on theoriginals being handled. The 3m color-in-color process is not an electrostatic copierprocess, but instead a heat-activated process in which infraredradiation causes dyes to be transferred onto a paper support. Since zinc oxide is a known photosensitizer ofcellulose, it is to be expected that direct electrostatic copieswill show greater instability on exposure to light For Sale Kodak Case Study
Since carbon black isquite stable and permanent, the stability of the resin binder is thelimiting factor. Druzik, the ozone fading of traditional natural organiccolorants on paper, 36. As glass transmits ultraviolet rays between 325 and 400nanometers, copiers with ultraviolet-producing lights such asfluorescent, tungsten halogen or xenon flash will expose documentsto some ultraviolet when an original item is liable to be copied repeatedly, a singlemaster copy can be used (and retained) to make further photocopies,in order to prevent wear and tear and excessive light exposure tothe original. The xerox machine made copies on plain paperand quickly gained market share in competition with electrofax typecopiers, introduced in 1954 by rca, which produced electrostaticcopies on a coated paper in 1960, an estimated 70 million copies were made Sale Kodak Case Study