CHAP. IX.

COPPER-PLATE AND OTHER PRESSES.

WOODEN ROLLER PRESS FOR PLATE PRINTING. HOW USED.CAST IRON ROLLER PRESS. DYER'S PATENT PRESS FOR PRINTING WITH PERKINS'S PLATES.

LITHOGRAPHIC PRESS.

STANDCOPYING

ING PRESS. ATHOL AND HYDRAULIC PRESSES. MACHINES. HAWKINS'S POLYGRAPH. — OTHER CONTRIVANCES

FOR COPYING LETTERS.

THE present chapter, although introduced under a new head, must, in fact, be considered as a continuation of the preceding one on iron printing machinery in general.

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A few years ago, the terms screw press, and "rolling press," or type press," and "plate press," would

have indicated with sufficient distinctness the methods of printing, and the kinds of presses then in use. Such, however, have been the alterations and inventions of late years introduced into the manufacture of machines for multiplying impressions on the principle of printing, that the roller is applied to the type form; the screw to the process of copying autograph letters; plates are cast in stereotype, as well as cut out of rolled copper or steel: and even stones, by a novel process uniting in some degree the two modes of type and plate printing, are made to yield, by the operation of lithography, a variety of exquisite and surprising productions; combining, with the utmost cheapness of material and facility of execution, the almost unbounded exercise of the arts of design.

The common roller press must, of course, have had its origin at the time when impressions first began to be taken from plates of copper engraved or etched on the surface, and this practice is supposed to be at least as ancient as the year 1540, about a century later than the date usually assigned to the invention of printing from movable types; though it has been said, that the art

was not employed in England before the reign of James I., having been brought over from Antwerp by Speed, the antiquary. The old wooden rolling press, and which appears to have undergone little alteration in general, is an exceedingly simple contrivance, consisting of two rollers, six inches or more in diameter, having trunnions or axles passing through the upright supports, and made to revolve by means of a cross, consisting of two levers, attached to the axle of the upper cylinder. Between these cylinders passes a board, called "the plank," upon which the plate, charged with ink, is laid to be printed from: the impression is produced by placing the paper, properly damped, over the plate, and then, by means of the cross levers, drawing the plank, with the plate and paper lying upon it, between the rollers; the uppermost of which, being covered with blanketing, forces the paper, as it were, into the interstices, and the ink adhering, an exact impression of the design on the metal is the result. Of these machines, constructed mostly of wood, many have been made with improvements, and at a very great expense, in modern times. They are now, however, manufactured of cast iron, by most of the iron press makers, and are made to

Fig. 74.

H

B

combine simplicity, cheapness, and efficiency, to a degree that has rendered them very common among en

gravers, whose means might have rendered difficult of attainment machines equally convenient and durable of any other material.

Fig. 74. is a representation of a cast-iron press adapted for printing from copper plates: although not so massy as to require the sinking of a considerable sum in mere weight of metal, it is nevertheless so stout as to answer efficiently the purpose for which it is designed. The whole fabric weighs about eight cwt. ABCDE indicate one side of a strong cast-iron frame, the width from A to B being, in the machine from which the description is made, three feet, and the height from the floor to the top of the pillar E four feet three inches. The two sides of this frame, which exactly resemble each other, are bound together by cross bars of wrought iron, fastened with nuts and screws at their extreme ends. F G are two cast-iron cylinders or rollers, two feet in length, accurately turned on their surfaces at a slide lathe, and working on iron axles passing through each side of the frame. The upper roller is nine inches and the lower one twelve inches in diameter. H is a stout plank of mahogany, or other hard wood, two inches thick, faced with plate iron, and about the width of the rollers; upon this the engraved plate is laid, when an impression is to be taken. The axles of both rollers rest upon brass bearings, which rise or fall in grooves, as seen in that side of the frame next the eye. At E, and in the corresponding upright on the other side, are screws to regulate the pressure of the rollers upon the plank; and, consequently, upon the plate laid thereupon. I is a pulley in a frame, upon a cross piece over the upper roller: its use is to carry a weighted string, for the purpose of detaining upon the cylinder the blanket, which, on being pressed upon the plate by the action of the rollers, effects the impression. K is a metal wheel, or cross lever, fixed on the axle of the upper roller: the handles or grips form levers, each of two feet six inches in length from the centre of the roller.

ob

In Dyer's patent for Perkins's plates and presses, tained in 1810, we find some striking improvements. In the following section of the machine, as constructed by Mr. Dyer, we find substantially the parts of that above described, as the upright support A, the rollers B C, and the lever wheel D. Instead, however, of the solid plank marked H in the former article, there is in Mr. Dyer's press a sliding table E, to the farther end of which, and passing over a pulley, is a string with a weight F attached, sufficient, when the table has been advanced, to bring it back to its present position when not acted upon by the roller. In this table at e there is a cell, containing a cast-iron box, for the purpose of containing a heater. A perforated plate rests in the rim of this box, above the heater; and upon it the engraved plate is placed, and may be kept at a proper temperature for a considerable time, without changing the heater or removing the plate, which obviates the inconveniency that would otherwise attach to the printing of thick and heavy steel plates. A still further improvement has been, the placing of a little stove with charcoal immediately under that part of the table upon which the plate is fastened, by which means an equal temperature is maintained in the plate, by its resting over this stove during every repetition of the inking process. Steam has still more recently been applied with success for heating copper plates when used for printing. The operation of the sliding table is as follows: The upper roller, instead of being a perfect cylinder, has, in one part of its periphery, a flat space, or, in other words, a portion of the material is cut away through the whole length of the surface. This being the case, it will easily be perceived, that, by turning the wheel, the table E is drawn between the cylinders, the counterpoise F rising accordingly; but that, on the upper cylinder having passed over the plate, and then presenting that part of its surface where it is cut away, it ceases to bear upon the table, upon which the weight immediately acting draws it back to its former

position, when the impression is removed, fresh ink and paper applied, and the operation renewed as before.

Fig. 75.

It might be deemed an omission in this notice of iron printing machines, were we to make no mention at all of the lithographic press; since its use in this country has not only become common of late years, but some of its productions are highly deserving of the admiration that has been bestowed upon them. The instrument, however, by the means of which impressions are taken from stone, as the name given to this art implies, although differing widely from those used in both letterpress and copper-plate printing, is only in a slight degree indebted to the smith for its materials or construction. We owe the discovery of this mode of printing to Alois Senefelder, a student of jurisprudence in the university of Ingoldstadt, in Bavaria, who, at the close of the last century, obtained impressions of music, drawings, and writing by this method. The principles on which it is founded are, first, the quality which a compact granular limestone has of imbibing grease or moisture; and, se