Helping San Diego, California and beyond since 1997.
Do you need
volunteer, community service, work, military or court hours?
|
|
Helping San Diego, California and beyond since 1997.
|
|
Click here and add this page to your favorites!
|
Encyclopedia Britannica - Main :: COM-COR |
|
|
COPYING MACHINES . Appliances of various kinds have been devised for producing copies of writings made by the pen or pencil. A simple method commonly adopted when only a single copy is required is to write the original
ordinary ink), to place upon it a damped sheet of thin absorbent paper , and to press the twotogether in some way, as in a copying press. The resulting impression, being reversed, must be read from the back of the absorbent paper , which is thin enough to be transparent. Another process, by which a considerable number of copies can be made simultaneously, consists in interleaving a number of sheets of thin white paper with sheets of paper prepared with lampblack (" carbon paper ") and writing on the top sheet with a " style " or other sharp
instrument , The hectograph may be taken as typical of manifolding processes analogous to lithography. In it the writing is in first instance done with aniline ink, and then a transfer is made to a plate
series of duplicates can be taken off. Another class of methods involves the preparation of what are essentially stencils. In the cyclostyle, paper of a special
plate
instrument consists of a holder having at the end a small wheel provided with a serrated edge on its periphery, which perforates the paper with lines of minute cuts and thus forms a stencil. When ink is passed over this stencil with a roller it goes through the perforations and leaves an impression on a piece of paper placed underneath. In the trypograph a similar result is attained by using a simple style for writing, but stretching the paper over a metal plate having its surface covered with fine sharp
series of minute holes is punctured in the paper by the act of writing. For copying plans and drawings, engineers, architects, &c., use a " blue print " process which depends on the action of light on certain salts of iron (see SUN-COPYING and PHOTOGRAPHY).End of Article: COPYING MACHINES If you wish, you can link directly to this article.
<a href="http://jcsm.org/StudyCenter/Encyclopedia/COM_COR/COPYING_MACHINES.html"> COPYING MACHINES </a> |
|
|
(Previous) COPYHOLD |
(Next) COPYRIGHT |
|
Sponsored Advertisements