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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.
Methods of copying handwritten letters Manifold stylographic writer, using early "carbonic paper" Letter copying book process; Mechanical processes Tracing to make accurate hand-drawn copies; Pantograph, manual device for making drawn copies without tracing, can also enlarge or reduce; Printmaking, which includes engraving and etching
A copying clerk would begin by counting the number of master letters to be written during the next few hours and by preparing the copying book. Suppose the clerk wanted to copy 20 one-page letters. In that case, he would insert a sheet of oiled paper into the copying book in front of the first tissue on which he wanted to make a copy of a letter.
When the solvent-impregnated paper comes into contact with the back side of the first sheet, it dissolves just enough of the pigmented wax to print the image onto the paper as it goes under the printing drum. One master can produce 40 or so good copies; after that, the copies gradually become paler as the colored wax is used up. [5]
The drum then transfers the image onto paper which is passed through the machine by direct contact. Finally, the paper is passed onto a finisher, which uses heat to instantly fuse the toner that represents the image onto the paper. The laser is typically an aluminium gallium arsenide (AlGaAs) semiconductor laser), which emits red or infrared light.
Copy paper is used for copying and laser printers. The basis weight is 70-90 g/m 2 (approximately 18-24 lb) and ISO brightness 80-96%. It is made of 90–100% virgin chemical pulp or 100% deinked pulp with total pigment content of 10-15%. The most important quality is smooth run in a copying machine / printer and good dimensional stability.
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The tabla consists of two small drums of slightly different sizes and shapes. [4] [12] Each drum is made of hollowed-out wood, clay or metal. The smaller drum (dayan/tabla) is used for creating treble and tonal sounds, while the primary function of the larger drum (baya/dagga) is for producing bass. They are laced with hoops, thongs and wooden ...