Roller

A hollow wooden cylinder covered with composition which, set in an iron frame, revolves upon a rod and is used for inking type. The test of a good roller is: It should be moderately soft to the touch, yet perfectly elastic and strung in texture. It should shrink but little, and yet Last a considerable time. To know when a roller that has been recently made or washed is in order, grasp it gently with the hand, or pass the ends of the fingers along its surface lengthwise. It it is in a raw, sticky condition, it is yet “green,” and must not be used. If it appears only moderately adhesive and pliant, but uniformly so, escaping from the fingers without showing a mark from them, and with a smooth rebound, the roller if is in good condition, and is best if mounted and charged with ink at once. A large poster or newspaper forme, or any large forme with old type, will require a soft roller with much suction. Book-work, wood-cuts, or tine job-work will require a harder roller, with a very smooth, elastic, and clinging surface. Coloured inks are best printed with a still harder roller and with much less suction.

All rollers should be perfectly clean and free from all cracks and holes. The suitable-ness of these rollers cannot be explained by words; such a knowledge will be best acquired by observation and experience. It may, however, be necessary to state that one roller will not do for all sorts of presswork; the quality of the work, the size and condition of the type, and the speed of the press must guide the pressman in his choice.

During the past few years various substitutes for the ordinary composition have been introduced. The most successful of these is that invented by Messrs. S. Moulton and Co., of Bradford-on-Avon. It is called the “Moss” Rubber Inking Roller, and is composed of a new and homogeneous material of the consistency of moss, and hermetically sealed in a smooth skin of specially-prepared india rubber. The advantages claimed for these rollers, as compared with the ordinary composition rollers, are: Their great durability, on account of the unchangeable nature of the material; they are wholly un-affected by any temperature; they are not damaged by use on brass rule; they are permanently soft and elastic; and they can be used immediately after being washed.—

To make composition rollers, put the glue in a bucket or pan and cover it with water; let it stand until more than half penetrated with the water, taking care that it shall not soak too long, and then pour it off and let it remain until it becomes soft, when it will be ready for the melting kettle. This is a double vessel like a glue kettle. Put the soaked glue into the inner vessel, and as much water in the outer boiler as it will contain when the inner vessel is placed in it. When the glue is all melted (if too thick add a little water), the molasses may be slowly poured into it and well mixed with the glue by frequent stirring. When properly pre-pared, the composition does not require boiling more than an hour. Too much boiling candies the molasses, and the roller consequently will be found to lose its suction much sooner. In proportioning the material much depends upon the weather and temperature of the place in which the rollers are to be used. Eight pounds of glue to one gallon of sugar-house molasses or syrup is a very good proportion for summer, and four pounds of glue to one gallon of molasses for winter use. For band-press rollers more molasses should be used, as they are not subject to so much hard usage as cylinder-press rollers, and do not require to be as strong, for the more molasses that can be used the better the roller.

Before casting a roller the mould should be perfectly clean and well oiled with a swab, but not to excess, as too much oil makes the face of the roller seamy and ragged. The end pieces should then be oiled, and together with the cylinder placed in the mould, the upper end piece being very open to allow the composition to pass down between the interior of the mould and the cylinder. The cylinder must be well secured from rising before the composition is poured in, by placing a stick upon the end of it sufficiently long to reach above the end of the mould, and be tied down with twine. The composition should be poured very slowly and in such a manner as to cause it only to run down one side of the cylinder, allowing the air to escape freely up the Other. If the mould be filled at night the roller may be drawn the next morning, but it should not be used for at least twenty-four hours after, except in very cold weather.

To determine when a roller is in order for working, press the hand gently to it; if the fingers can be drawn lightly and smoothly over its surface, it may be said to be in order; but should it be so adhesive that the fingers will not glide smoothly over its surface, it is not sufficiently dry and should be exposed to the air.

Rollers should not be washed immediately after use, but should be put away with the ink on them, as it protects the surface from the action of the air. When washed and exposed to the atmosphere for any length of time they become dry and skinny. They should be washed about half-an-hour before using them. In cleaning a new roller, a little oil rubbed over it will loosen the ink, and it should be scraped clean with the back of a case-knife. It should be cleaned in this way for about one week, when ley may be used.

New rollers are often spoiled by washing them too soon with ley. Camphine may be substituted for oil, but owing to its combustible nature it is objectionable, as accidents might arise from its use. Mr. Hansard, an eminent English printer, says: “Take glue made from the cuttings of parchment or vellum, fine green molasses, pure as from the sugar refiners, and a small quantity of the substance called Paris White, and you will have every ingredient requisite for good composition. The proportion as follows: Glue, 2 ℔s.; molasses, 6 ℔s.; Paris White ½℔. Put the glue in a little water for a few hours to soak; pour of the liquid, put the glue over the fire, and when it is dissolved add the molasses, and let them be well incorporated together for at least an hour; then with a very fine sieve mix the Paris White, frequently stirring the composition. In another hour or less it will be fit to pour into the mould.[”] Various patented compositions for rollers may now be had from printers’ brokers.