STATIC ELECTRICITY IN PAPER
Among the “paper troubles” due to conditions for which neither the paper-maker nor the printer is responsible, none is more bothersome than the presence of static electricity in paper. These static charges, which are created by friction either in the making or handling of paper, develop magnetic propensities in the sheets, causing them to behave in ways which seem nothing but freakish until their nature is understood. Some sheets stick together as if they were glued, while others appear repellent to one another. Likewise, they may act in the same manner toward the fly-bars of the press. It is next to impossible to “feed” sheets so charged, and there is every likelihood of the ink from one sheet offsetting to another.
Every one familiar with the magnet knows that there are in magnetism two poles, the positive and the negative; that two substances of opposite polarity attract one another, but that substances of the same polarity repel each other. Static electricity—or frictional electricity, as it is also called—exists both in positive and negative charges, and sheets of paper containing static charges are governed accordingly.
Paper, when dry, is an insulator to electricity, but when moist it becomes an excellent conductor. Consequently, too much drying in manufacture increases the likelihood of electrical troubles, because it makes the paper more retentive of electricity with which it may become charged.
Pure air is also an insulator of electricity, which finds its paths through the air by means of the dust particles in suspension. Moisture in the air forms a connection between the dust particles through which the electricity easily passes into the ground, but when the air is dry this medium is lacking, so that substances containing static charges are deprived of these channels of conductivity. Cold air can not hold so much moisture as warm air, so that its insulating properties are increased. It is, consequently, in cold weather when this sort of paper trouble is at its worst.
These facts suggest the first steps of prevention to take against static electricity. First keep the air in the pressroom warm, and, if necessary, increase its humidity. It is also advisable to keep the paper in a warm room, for it has often been noticed that paper coming cold into a pressroom gives much trouble.
The entire virtue of the so-called electric annihilators for moistening the tympan of a press comes from the moisture they contain. Ordinary glycerin, which is cheaper, will answer as well. These applications are undesirable because they cause the packing to swell, and, in consequence, detract from the adjustment of the overlays.
There is a simple and not very expensive device on the market called the Thompson electrical neutralizer that has been found helpful. It is provided with a tinsel cord such as is used in decorating Christmas trees. The cord is stretched across the press so that the sheets are brushed by it as they pass to the delivery board, and are thus offered a connection whereby the static charges may escape into the ground. A second device of merit consists in a gas pipe with flames at frequent intervals over which the printed sheets pass in close proximity on their way to the delivery board.
The most successful neutralizer with which the writer is personally familiar is the Chapman. By means of an alternating current of electricity, it supplies through a special apparatus alternating discharges of positive and negative electric currents against the sheets of paper as they are carried along the press. In the presence of such a current the charges on the paper become their own destroyers, as they draw out of the alternating current only the kind and quantity of electricity which is sufficient for their complete neutralization.
There have been quite a number of other inventions, an account of which the writer published in The Printing Art, Vol. XIX, No. 1, March, 1912. All are based on one of the following principles:
1.—Making paper a conductor by moistening.
2.—Making the air a conductor by humidifying.
3.—Inducing static charges out of the paper by means of grounded wires or gas flames.
4.—Neutralizing the static charges in the sheet with charges of opposite polarity.
Another solution of this problem, as well as of the problem of expansion of paper and consequent poor register, could be reached by the construction of an insulated pressroom. The air for this room should be supplied through an apparatus in which it could be brought to any required degree of temperature and humidity. The paper would naturally have to undergo sufficient airing in such a room as to become acclimated. After that, if the conditions remained constant, there could be no difficulty in getting register, so far as the paper was concerned, and a proper amount of warmth and moisture would also dissipate all static electricity.
It is difficult to anticipate or to completely cover all conceivable paper troubles, and when some one which may not be diagnosed on the basis of the general principles enumerated, consultation with some paper expert should clearly be sought. The author will be glad to communicate on such subjects.
CHAPTER ELEVEN
THE PAPER TRADE
The distribution of paper is cared for in part by direct sales from the mills to consumers, such as large publishers of newspapers, magazines, and books, and manufacturers of paper commodities, such as tags, boxes, stationery, toilet accessories etc.
The sale is also conducted to some extent by brokers, who operate principally in a few of the larger cities, especially those located within easy shipping distance from the mills, where the handicap of not carrying a large warehouse stock is at a minimum.
The broker carries no stock as a rule, with the exception of a supply for regular contracts. Occasionally the mills will carry a stock for the broker. A few firms specializing on contract business have made distinct successes in this branch of the paper business, but the broker is not an important figure in the paper trade, taking the country as a whole.
The most important distributing factor to the printing trade, is the paper merchant, who with his large purchasing power, accumulates ample and varied stocks, at minimum cost (having the advantage of carload prices and freight rates), and stands ready to distribute in large or small quantities, whatever is required. He also helps in a considerable measure to finance his trade by extending credit.
There is a distinct tendency toward “chain stores” one of the more prominent of which now comprises eight warehouses and seventeen branch offices, covering practically the entire country. These large factors frequently control the entire output of several mills, and sell to the smaller jobbers, as well as to the printers and consumers.
Statistics on distribution are apparently lacking, since the Government has never regularly compiled them, and the National Paper Trade Association, composed of paper merchants was unable to furnish any. The only estimate the author has obtained, comes through the President of the American Paper & Pulp Association, (The Manufacturers’ Association), who wrote on Jan. 22nd, 1914—