Copier-duplicators, often referred to as "stencil-duplicators" are copying devices that have been recently developed for replacing the old "mimeo" type duplicators. Such mimeo machines were clumsy, had poor print quality, and employed a chemical system to generate copies which has an offensive smell. Nevertheless, the old mimeo machines were less expensive to operate as compared with xerographic type photocopy machines, which has accounted for the popularity of mimeo machines, especially in school systems.
Several years ago it was discovered that the chemical system employed in mimeo machines is hazardous to human health and the use of the conventional mimeo machine has consequently been curtailed in many locales.
The copier-duplicator has thus become the obvious and popular substitute for the conventional mimeo machine.
A copier-duplicator employs facsimile technology to simulate the functions of the old mimeo machine and also has many additional performance enhancements which include ease of operation, improved print quality, and odor-free copying. The copier-duplicator functions in much the same way as a xerographic type photocopy machine. The operation is such that an original is placed in a facsimile style feeder, where it is scanned as it is slowly drawn into the machine. A master is prepared from the scanned original by way of a printer similar to a facsimile thermal printer and simultaneously therewith the master is automatically wrapped about an ink drum. Once the master is completed, which task typically requires about thirty seconds, copies may be made in a manner similar to a printing press.
The ink from the drum carrying the master transfers through the openings in the master and on to blank paper, creating copies. Copies are produced much more rapidly than the copy production rate of photocopy machines and are produced at a greatly reduced cost. Although the cost of paper is the same, copier-duplicators require only ink whereas photocopy machines require toner, fuser oil and utilize a selenium drum which deteriorates as copies are made and has a limited useful operating life. Nevertheless, the copier-duplicator operator is not aware of any of these advantages or disadvantages. The operator need only be concerned with entering the number of copies required and thereafter pressing a "start" button.
Although the copier-duplicator has distinct advantages, one of which is economy, the copier-duplicator can be more expensive than a photocopy machine under a particular set of circumstances, most typical occurring when a master (which is comparatively expensive) is produced for the purpose of making only a small number of copies. Since the master typically costs from $0.30 to $0.75 to produce and cannot be reused, the total cost for a copying session can be relatively high if only a few copies are made, the price per copy being a function of the cost of a copy plus the cost of the master divided by the number of copies being produced by said master.
To illustrate this point, consider a copier with a cost of $0.05 per copy and a copier-duplicator with a cost of $0.50 per master and $0.01 per copy. The cost for making five copies on the copier is $0.25. However, the cost for making the same five copies on the copier-duplicator is $0.55. At ten copies, the total cost of copies on the copier is $0.50 while the cost for the same number of copies on the copier-duplicator is $0.60. The break-even point occurs at thirteen copies in the example given, i.e. for less than thirteen copies the copier is cheaper and for thirteen or more copies the copier-duplicator is cheaper.
Since copier-duplicators are typically sold based on the fact that their cost per copy is less than that of a photocopy machine, it is important to be able to prevent abuse by lax or unconcerned users.