Mechanical composition: slugcasting typesetters
The Linotype and Intertype slugcasting typesetters produce lines of letterpress composition in a single operation, starting with the assembling of the movable matrices. The letter matrices are thin, brass 19 × 32-millimetre (0.7 × 1.3-inch) plates, with two ears and a system of 14 notches arranged in a V on the upper surface and two heels in their lower part. The letter is engraved in intaglio on the face surface; usually two copies of the same letter are superimposed (duplex matrices)—one normal, or roman, the other a variant, either italic (sloping design) or boldface (stronger design). Thus, their thickness varies according to the letter and the body of the character.
The set of matrices is stored in a magazine, a flat, trapezoidal metal box consisting of 90 channels in which the matrices are aligned one behind the other, duplicates of 20 or 24 for each letter or sign, lying face down, resting on an ear and a heel.
Blanks are introduced into the line in two ways: either by using unengraved blank matrices, included in the magazine in three standard sizes, or by using spacebands designed to ensure justification.
The operator sits in front of a keyboard with 90 keys, corresponding to the channels in the magazine, on the left the lowercase letters, on the right the uppercase letters, in the middle the small capitals, numbers, and various symbols. A special bar operates the release of spacebands.
Slugcasting typesetters function as follows: (1) Touching a key releases the matrices, which are brought in proper order on a conveyor belt to a composing stick made of slide-bars and held by their ears. The spacebands, which are stored directly above the composing stick, fall into place between the words. (2) When the matrices and spacebands in the composing stick visibly take up the amount of space planned for the length of the line, the operator completes the line, either with a whole word or by dividing the last word, and pushes a lever to move the line. Since the remaining operations are done automatically he can go on to set the next line. (3) The assembled matrices and spacebands are moved three times in succession: vertically upward on the composing stick; sideways to the left on a transfer slide rest; vertically downward on an elevator that puts them in front of the opening of a mold mounted on a cogwheel called a mold wheel, connected to an electric melting pot containing the molten lead alloy. (4) A justifying hammer forces the long pieces of the spacebands upward, forcing them to separate by equal spaces until all the matrices and spacebands are locked between two steel jaws fixed at the precise justification of the line. A piston plunges into the melting pot and forces the alloy into the mold to cast the line. (5) While the mold wheel rotates three-quarters of a revolution and the solidified line is finished to its exact letterpress height before it is ejected into a galley, the matrices and spacebands are again moved upward by the elevator. (6) They are pushed to the right toward a triangular bar bearing 14 grooves corresponding to the 14 notches in the matrices. (7) Raised by a catcher arm, this bar removes the matrices, which are caught by their notches; the unnotched spacebands are released and immediately return to the place where they are stored. (8) When the catcher arm is at its highest position, the matrices are pushed to the right toward another triangular bar with 14 grooves along its length and flush with the top part of the magazine; this is the distributor bar. (9) The matrices move along the distributor bar until at a certain point the arrangement of grooves ceases to provide support for the notches, which of course are different for each letter or sign. Each letter’s matrix is then released at the opening of its own channel in the magazine.
The automatic cycle of the typesetter is controlled by several large cams mounted on a single shaft driven by an electric motor.
Modern typesetting machines are equipped with several magazines of varying type sizes that can be used alternately. Some so-called double-distribution machines permit two magazines to be used at once by pressing a supplementary key.
The performance of recent models has been improved by accelerating the revolution of the matrices, intensifying the cooling system of the mold, and increasing the number of molds on the mold wheel to six.
The slugcasting typesetter, which furnishes solid, easy to handle, composed type, is particularly suited to printing newspapers. It has the disadvantage that to correct any error, however trivial, the whole line must be recomposed.
The All-Purpose Linotype is a combination manual and automatic machine that retains only the casting part of the Linotype. Special matrices, solidly rectangular or with notches, ears, and heels, are assembled by hand in a composing stick. Justification is done with blank matrices of various sizes. The line of matrices, held by the composing stick, is placed against two set squares fastened to the bedplate of the machine and manually pushed on a slide rest, which takes it to the elevator. The elevator places the matrices in front of the opening to the mold for the casting operation, which delivers the slug. The matrices are then distributed by hand.
Typesetter casting aligned characters
The operation of the Monotype typesetter, which casts individual aligned characters, is based on a system of measuring the width of characters, called the set. In each font, letters and symbols have sizes determined in units of set, from five units for the narrowest, such as the “i” or the “l,” to 18 units for the largest, such as the “W” or the “M.”
The Monotype keyboard, separate from the caster, consists, on the standard model, of 274 keys, 30 of which, in two rows numbered from 1 to 15, are called justifying keys. Typing out the text results in the perforation, by an automatic punch, of one or two holes, each letter or symbol having its own pattern, in the width of a paper tape that allows 31 possible arrangements. An automatic calculator adds the widths of the letters and symbols typed out. Moving his forefinger across a scale that he has before him, the operator knows when the end of a line is near. Once he has finished a line, he places his other forefinger on the justifying drum, which indicates which two justifying keys he must now press. This move results in the perforation of one or two holes whose position indicates the quotient of the number of units lacking for the line to be completed by the number of spaces between the words of this line, plus a third hole in a position specifically fixed for the justification process.
The typesetter is composed of an electric melting pot containing molten alloy situated under a mold in the shape of a vertical chimney, the internal dimensions of which can vary according to the measurement in units of set of the characters or spaces to be cast.
The matrices are in the form of small bronze cubic blocks measuring five millimeters (0.2 inch) square, arranged in a steel frame nine centimeters (3.5 inches) square containing 15 rows of 15, enough for five complete alphabets, typically uppercase and lowercase in roman, italic, and boldface, and small capitals, as well as double or triple letters, numbers, and punctuation marks. Each row includes only matrices of letters and symbols of the same unit of set, from the smallest (five units) in the first row to the largest (18 units) in the back row.
The frame can slide horizontally in either direction to place any matrix from any row above the opening to the mold.
The process of setting and casting type on the Monotype is as follows: the roll of perforated paper tape is placed in the pneumatic tower of the typesetter—a row of 31 pipes distributing compressed air. As it unrolls, the tape prevents the compressed air from entering all pipes except those corresponding to the perforations.
The tape unrolls in the direction opposite to that in which it was rolled up—that is, in the opposite order to the way it was typed, the last line appearing first and the justifying perforations being inserted into the pneumatic tower before those for the letters and symbols. The compressed air that the perforations allow to pass into three (or two) of the pipes causes pieces of metal (justifying quoins) to fall into position in such a way as to control the internal measurement of the mold each time that the spaces between the words of the next line are to be cast.
The perforations for each letter or symbol allow the compressed air to pass into two (or only one) of the pipes connected to two blocks, each of which also contains a series of graded pins. Compressed air raises a pin in each block and halts the movement of the matrix frame in either of its sideways movements. In this way the matrix’s row and the matrix’s place in its row are selected. Selecting the row is the same as selecting a measurement given in units of set. Positioning the row is automatically linked to setting a piece of metal (the set quoin) whose position regulates the dimensions of the mold for casting the letter or symbol.
For the casting, a centering device places the selected matrix precisely against the opening of the mold, and a plunger in the melting pot forces the alloy up to cast the character or the space (that is, the unengraved matrix).
The composed line emerges from the machine completely assembled and justified and is placed in a galley.
The Monotype can cast type ranging in body size from five to 24 points (with a special mold for each). The addition of a speed-reducing device enables it to cast in 48 points. The maximum width of lines assembled is 60 picas.
In the early 1970s Monotype models could be equipped with a frame carrying 15 rows of 17 matrices (255) or 16 rows of 17 (272), with six or seven complete alphabets. The keyboard then has 310 keys.
A special model of the keyboard permits simultaneous perforation of two tapes for composing the same text in identical or different kinds of type and lengths of line.
The advantages of the Monotype system are the quality of its composition and the ease with which corrections can be made without having to reset the whole line. It is not well suited to newspaper printing because of the difficulty of handling lines of movable type and because, since typecasting begins with the end of the tape, composition must wait until all the type has been cast.
Automatic composition (perforated tape)
The Teletypesetter (TTS) system extends to slugcasting machines the principle of separation of function originally characteristic of the Monotype: it enables Linotype or Intertype machines to be controlled by a perforated tape produced on a separate keyboard, even situated in a different city, since the combination of the perforations on the tape can be sent telegraphically.
The Teletypesetter tape is six-channeled; that is, it contains six possible positions for perforations across its width. This allows 64 different combinations of from one to six perforations.
This limited capacity, less than the number of keys on the keyboard of the typesetter, is corrected by an arrangement whereby each combination of perforations may have two different uses (for example, the uppercase and the lowercase of the same letter) according to whether it follows one or other of two special signals (themselves represented by combinations of perforations) that control passage of one or other of these uses.
The keyboard for preparing the Teletypesetter tape looks like a typewriter with, in addition to the usual 44 keys and the space bar, 20 special keys. Striking each key establishes contact with the electric circuit or circuits that operate the perforators and at the same time acts on a calculating mechanism: a needle moving across a screen warns the operator of the end of each line.
Usually, as the tape is perforated the text is also typed out on a sheet of paper, which allows the work to be checked, reread, and corrected. For use with a Teletypesetter, the typesetting machine is equipped with a mechanism that translates the tape. In this mechanism the tape passes under six sensors that register electric contacts as the perforations pass. In accordance with the combination of electric contacts thus established, relays control the action of the keys or of the bar that causes the spacebands to drop and, at the end of each line, the starting of the casting cycle.
The most recent typesetters specially designed for use with the Teletypesetter offer such technical refinements as the elimination of the composing stick and immediate dispatch of the line to the elevator, simplifying the path taken by the matrices; and electromagnetic, rather than mechanical coupling, which speeds the starting up of the casting cycle.
