FEEDING MACHINE. By this name are commonly known the machines used to au tomatically supply printing-presses or the like with paper sheets. Printing of a high grade is not done on the great web printing machines, which feed from a roll of paper. Those are built for speed, but for fine printing presses of the single cylinder type, using single sheets of paper are almost universally used. Such presses were always fed by hand until about 1895, when the first practical paper-feeding ma chines for printing-presses began to come into use. The first of these machines to secure a considerable sale was the Economic feeder. A little later the Dexter pile feeder came in the market. This machine is attached at the rear of a cylinder printing machine, and lifts a sheet of paper from the top of a pile by first buckling the two rear corners, then blowing air under the buckled sheet to separate it wholly from the rest of the pile, after which the sheet is advanced or pushed forward to the guides of the press by means of rubbers and traveling endless tapes. The pile of paper from which the sheets are fed is placed on a platform that is arranged with mechanism for raising it very slowly, so that the top of the pile is always kept at substantially the same level. The per fecting of these machines has been obtained only after very costly experimenting, and the addition of improvements as defects were found. Paper piled in sheets has a tendency to stick together, in fact, sheets are sometimes actually glued in spots, as by the crushing of an insect between them. The automatic feed ing machine has to provide for such contin gencies, and when a torn sheet is found, or a wrinkled one, or two sheets stuck together, the feeder must not only be stopped, but the print ing-press also must be brought quickly to a standstill or damage results. Ingenious auto matic devices have been introduced for control ling these conditions, and the machines are now commonly used in connection with the printing of magazines of large circulation, some of the larger magazine and book printers employing as many as 30 or more feeding machines in one establishment. The Dexter machines will ac
commodate 10,000 to 20,000 sheets of paper at a single loading, which saves the time formerly lost by the hand feeder about once in 1,000 sheets, in stopping to put up another pile. There is also a saving in soiled sheets, in wages paid, and often in the speed at which the print ing-press can be run. A few years ago the Dexter Company brought out the reloading feeder, which has an auxiliary table or piling board, permitting the reloading of the machine with a very trifling stop. Dexter was the first to introduce a machine driven by floor connec tions, which secures greater rigidity than when driven by a chain from the cylinder of the press. Non-electrical devices are employed throughout, some of the most ingenious being the devices for calipering the sheet, to make sure that two sheets do not go into the press together, and the controlling apparatus for trip ping the impression of the printing cylinder if a sheet is missed or fails to mine down properly to the guides. The Dexter Company also builds folding machines, and their feeders are adapted to use with these, as well as for ruling ma chines.
The Cross continuous paper-feeder, made also by the Dexter Company, does not occupy any floor space, as do those previously de scribed, being located above the feed-board of the press. It accommodates several hundred sheets at a time and reloading is accomplished without stopping the press. It requires no ad justments for quality or weight of paper, and is practical for short as well as long runs. The sheets of the pile are combed out, then turned completely over and reversed in direction and guided one by one to the feed-guides of the press.. The Harris printing-press, a job rotary machine, built in a great variety of styles, em ploys a feeding mechanism that should be men tioned in this connection. It automatically picks an envelope or card from the bottom of a pile and carries it into the press. It will also feed very light and thin papers with accuracy. All the modern automatic job presses now em feeding mechanism as a part of their equipment. See PRINTING; FOLDING MACHINES.