CHAPTER II.

Platen Machines—Mechanical Features

Platen machines are made in various sizes. Where power is used the demy folio, crown and even demy sizes are more or less popular. Treadle machines are usually in royal octavo (7 x 11 ins.), foolscap folio (9 x 13 ins.), crown folio (10 x 15 ins.), demy folio (13 x 19 ins.), royal folio (13 x 20 ins.). These sizes are inside measurements of the machine chases.

The machines now in general use are distinguished by trade names which identify their manufacturers but do not indicate their principles or special features. They have features common to all, but some of them possess improvements of their own, adapting them for particular classes of work. The most popular class of platen machine for half-tone work, three-colour and the heavier class of printing, is that represented by the Victoria, Phoenix Caxton, Harrild, Conqueror, and kindred machines.

The original inventor of the small platen machine was Gee. F. Gordon, an American. His machine, called the Franklin Press, was brought over to England and manufactured for many years by the Croppers, a firm of engineers, who re-named it the Minerva. Hence it has since been known as the Cropper or the Minerva machine. This style of machine is largely used for light, ordinary work, but later machines have been adopted having greater strength, speed and rolling facilities. The Cropper being the prototype of the class requires to be noticed first.

In the hand press, as already pointed out, the forme is laid on a horizontal table, or bed, and is run along the ribs until it is brought under a horizontal platen, which, descending, produces the impression on the paper beneath it. In the ordinary platen machine a different principle is adopted. The is placed in a vertical position, and when the platen is brought into contact the paper between them is impressed. The vertical principle of the machine, as compared with the horizontal principle of the press, reduces the amount of labour involved to one-tenth, whilst permitting of an output ten times as great, as some of the motions are automatic and the apparatus driven either by treadle or by power.

The Cropper machine consists of two side frames held together by iron stretchers. To these frames all the working parts are connected. The back part consists of a bed into which the forme is fitted in a perpendicular position. Over this is the inking apparatus. The front part consists of a platen at an angle of about 45º when stationary. The sheet is laid to pins or gauges of some kind on the platen, which is pulled forwards toward the forme by two strong steel arms, one on either side, such action causing the impression. The platen returns to its original position and so remains sufficiently long to enable the operator—usually a boy, often known as a “Cropper hand”—to take off the printed sheet with his left hand and lay on another sheet with his right hand.

Inking Arrangements. In small machines there are two composition rollers, or inkers, and one distributor. The latter receives its ink from a “duct,” the construction of which is described in chapter iv. which deals with cylinder machines. The inker distributes the ink over the ink plate, which is a disc, and may be in two or more parts revolving in different directions, in order to facilitate the distribution. The two inkers travel on bearers down the front of the bed, in the course of which movement they ink the forme. This is done while the machine is open and the layer-on is removing one sheet and placing another in position.

These motions are effected as follows :—The shaft bears its extremity a small spur wheel which works a large wheel. To this latter is attached a strong steel rod connected at the other end with a frame which works loosely upon fixed bearings. The rollers, generally three in number, the fitted into forks in a frame. The movement of the latter is effected by the revolution of the large wheel holding the steel arm. The perpendicular travel of the rollers is caused springs attached to the fork which pull the inkers with the surface of the forme, allowing them to run in on to the almost flat ink disc on their return. For this purpose the rollers are fitted with flat wheels running on guides. The latter ensure steady motion and support and prevent a roller from being damaged by undue pressure.

Feeding Arrangement. Fitted round the edge of the platen are two wrought-iron bands, hinged in the centre, which may be lifted up separately. When closed down these act as clips, which secure on the platen the corres­ponding to that in the press, but which is therein placed between the outer and inner tympans. The sheet of paper is secured to the platen in its descent by two flat pieces of steel or gun-metal, about 10 inches long, three-quarters of an inch wide and one-eighth of an inch thick. These act like fingers, opening at one time and closing at another-that is when the sheet has to be kept firmly down. They are by a stationary cam, fixed on the side frame, and lie, platen goes down they mechanically close on the paper. For convenience of adjustment to different sized sheets they can be moved along a gripper bar from side to side.

Regulation of Impression. The forme, locked up in the is fastened to the bed by a chase catch, so made that it its hold instantly when the forme has to be removed. Behind the platen at the four corners are four screws which enable the platen to be perfectly levelled, so that at the proper time it will be precisely parallel to the bed. When the machine is adjusted for level impression these screws do not require alteration. The degree of impression is varied by a screw on a rod which is conveniently placed at the right-hand of the layer-on. This rod is connected with an eccentric shaft at the back of the machine which varies the pressure on the forme.

The best machines in this class are provided with a useful contrivance called a “throw-off.” This stops impression, arresting the motion of the platen. It allows of the ink run up while the forme is in position and prevents a laid sheet being spoiled. The throw-off in the Cropper is put in operation by turning to the left a knob, to the end of the impression rod, which has been already mentioned. Other machines utilize different devices for the same purpose.

The whole operation of printing, except the supply and removal of the sheets, is done automatically by the machine, which in the absence of power, may be driven by treadle.

The Cropper, or Minerva, is a compact and simple machine, nevertheless it lacks certain qualities which are essential when attempting the best kinds of modern printing. Hence the attention of printing machine engineers has been directed to greater strength of impression, increased inking and distributing power, more convenience in making ready and higher rate of output.

The Improved Franklin (Cropper, CharIton & Co., Ltd.) is made on the Cropper principle. The framework is cast in one piece and fitted with special ink duct and distributing roller. Other new features are : the supply of ink from the duct can be varied without stopping the machine ; the ink feed can be varied or stopped automatically, according to the variation or throw-off of the impression; there are a distributing roller, which passes only over the ink disc, and three inking rollers, all of which pass completely over the forme ; a flexible steel knife with adjusting screws is applied to the ink duct ; this allows of varying amounts of ink being supplied to different parts of the forme when printing two or more colours at one impression ; the ink cylinders can, be lifted entirely away in such a manner that the knife and cylinder can be easily cleaned and the cylinder put back into its place without the necessity of adjustment.

The machines are now made with either right or left-hand Check Motion, and when required to be driven by electric power a suitable flywheel is sent with a flange cast upon the same so that the machine can be driven direct from a pulley on the motor without the use of fast or loose pulleys. The motor is controlled by the operator by simply moving the striking rod which controls the electric switch and this starts, or stops the machine instantaneously.

As examples of modern platen presses mention may be made of the following machines:

The Art Caxton Platen

is a British-built machine constructed with cylindrical inking and parallel approach of platen to type bed. It is exceedingly strong, and is intended not only, for the highest grade of letterpress and colour printing but is also designed cope with heavy work, such as embossing, carton cutting, plate marking, etc., all of which can be carried out upon this class of machinery. The impression is obtained by the impact of a moving platen upon a stationary bed. This moving platen is a single heavy, casting rolling along suitable supports until it is perfectly parallel with the face of the type, when it moves inwards with an absolutely square impact.

The framework of the machine is a single massive casting of great strength and stiffness, of which the type bed forms an integral part. The platen is also a single heavy casting, whilst the surfaces of both platen and type bed are not only planed true but are also hand scraped to Whitworth surface plate standard, which ensures a perfect impression over the whole of the forme. The platen and type bed are connected by massive side arms of best wrought-steel and rectangular section and are backed by heavy steel shafts accurately ground. These side arms are designed to withstand a breaking strain of 100 tons. The shaft at the back of the type bed is furnished with two massive gears, one at each end, which carry the crank pins upon which the side arms work. Most machines are furnished with a flywheel on either side. It is claimed for this method of construction that tortional stresses in the shaft at the back of the type bed are eliminated and the press will do better work and last longer.

The inking arrangements, which are successively elaborated in different models, are designed to cope with the most exacting, conditions. In all models there is a powerful distributing system above the forme. The ink supply is governed by a flexible steel knife, capable of fine adjustment, and is thoroughly broken tip by means of a succession of composition and steel distributing rollers which charge two large reciprocating distributing drums. These drurns charge four large inkers which measure 2¾ inches in diameter in the three best models, these inkers being, interchangeable with the distributors. The inkers work upon adjustable tracks, so that their pressure on the forme can be easily regulated, and those models which are furnished with a single inking system have their forme rollers so arranged that certain of them are held in reserve as the roller carriage travels downwards, and these come into play while the roller carriage travels upwards, thus ensuring that the forme is inked with fully charged rollers from either side. In a more elaborate model there is a more perfect arrangement still. In this machine, known as Art Caxton Model A, there is not only a powerful inking system above the forme, but below are reciprocating distributing drums. All four ink rollers are in contact with the forme on the downward travel of the roller carriage, and when these reach the bottom of their stroke the ink left upon them is thoroughly worked up and equalized by the three drums below the forme, so that they are practically freshly charged on their return upwards. Model B is still more elaborate. This machine is furnished with a duplicate ink duct and distributing system below the forme so that when the rollers reach the bottom of their travel they are completely recharged, the forme therefore being double rolled.

Besides these main features the Art Caxton Platens have a special device which is of great value when the press is used for the double purposes of printing and embossing. This is what is called a “two-position platen”. By means of this device it is an easy matter to increase the platen opening by five thirty-seconds of an inch above type height without disturbing the impression latch blocks. This increased platen opening is necessary to admit of the introduction of a thick force when embossing with type-high dies. It is useful when printing book covers and is exceedingly valuable for carton cutting, as it allows of the face of the platen being protected by rneans of a thin plate of brass or mild steel.

The Caxton is made in two sizes—demy and demy folio. A crown folio machine of this type has also been produced and is known as the Caxtonette.

The Sterling

This machine is made in demy folio size. The main body of the machine is one strong, box casting with which the typebed face, platen supports and main bearings are incorporated. The platen is cast in one piece and is fitted with turned steel shaft, depressible grippers and adjustable feeding gauges which are very simply adjusted. The impression is adjusted by two segments, one each end of the platen (usually only one segment is used by other makers on this size machine), which can be set to the greatest accuracy. The impression check is made in a very substantial manner and is very easily operated. The ink distributing drum has a lateral movement and is fitted with distributing and steel rider rollers. The ink duct is fitted with steel knife which is well regulated by adjusting thumb screws. The levers are made in either wrought-iron or cast-steel, the shafts and connecting link are steel forgings. Altogether this is a serviceable and well­made machine.

The Acme Platen

Of foolscap folio size, this is especially useful for jobbing work and has a dead dwell oil the impression, the platen being securely supported by an approved locking device. The impression is regulated by means of an adjustable clieck apparatus with ease. The machine is fitted with three rollers and one distributing roller which pass over the ink disc, depressible grippers, adjustable feeding gauges and ink duct, which is fitted with flexible steel knife and adjusting screws. The cylinder of the duct can be turned up from1 the knife for easy cleaning. The machine is run by power, steam gear with brake being provided therefor.

The Paragon Press

The NO. 2 Paragon Press, size 11 x 7 inches inside chase, is typical of a machine designed for small high-class printing. The type bed is cast with the main standard in one piece. The roller bearers are adjustable. It is fitted with ink duct with flexible steel knife. The cylinder of the duct can be raised for cleaning. It has one distributing, roller and three inking rollers. The grippers are depressible. The impression can be checked at any time by a simple and easy movement. The machine is strongly built and runs very smoothly by treadle.

The Falcon Safety Platen Press

This machine, patented and manufactured by Waite & Saville, Ltd., Falcon Works, Otley, embodies the features of an ordinary platen with the addition of a safe Wharfedale feed and self delivery. The principal object is to eliminate any danger to the feeder and, at the same tinme, greatly increase production. The machine is claimed to yield from two to three times the output. of any other platen, as the relieved of the taking off. Nearly three-fourths of the time occupied by the whole operation is now rendered available for feeding, thus leaving both hands at liberty for stroking in the sheets. The sheets are fed on the flat on a feed table with adjustable gauges, and are thence taken, printed and delivered, printed side up, without the aid of tapes or flyers, thereby obviating the risk of smearing. The feed table is detachable and can be lifted off, leaving the platen fully exposed and accessible from all sides. The necessity, for sticking quads, etc., on the platen is dispensed with, as the metal gauges on the feed table can be readily adjusted in a few seconds.

A novel arrangement on the type bed enables the operator by means of a small hand wheel, to move the forme up or down to the desired position and there lock it.

The inking, arrangements are easily controlled. Three rollers of large diameter, deriving. their supply of ink from a circular distribution plate, pass twice completely over a full forme. The circular plate is charged from an ink duct, which can be regulated without stopping the machine to pick any number of teeth, from 0 to 6, thus allowing it to be controlled with great nicety.

In regard to register, the platen is brought to rest to receive the impression on a broad seating, or shoe, and any variation is thus rendered impossible. The sheet is taken from the feed-plate by the platen itself, no other intermediate carrying mechanism being employed.

After being, printed, a set of grippers, mounted on a swinging gripper shaft, lays hold of the sheets, takes them. to the delivery board and there deposits them in a pile, printed side up, without risk of smearing. It delivers a full-sized sheet or a visiting card, no adjustment being required.

The Express Falcon

prints a sheet 10 x 6½ inches. It is the smallest size made of this class and is fitted with detachable automatic envelope feeder. It runs at a very rapid rate. For printing ordinary stock the automatic feeder can be replaced by the usual feed table in one minute. The makers claim this to be the fastest platen in the world.

The impression is firm and rigid. Instead of the ordinary plan of driving a platen press by means of a spur wheel and pinion at one side only, the Falcon has large spur wheel and pinion at both sides, thus having double the driving power, giving equality of impression, and longer life. The platen is operated by a new method and its construction obviates the necessity for the type to be in the centre of the bed-the printing can be done equally well with the type at edge of platen as in the centre. This arrangement renders slurring impossible.

The inking arrangements are ample and easily controlled. Three rollers of large diameter, deriving their supply of ink from a circular distribution plate, pass twice completely over a full forme. The circular plate is charged from an ink duct, which can be regulated without stopping the machine to pick any number of teeth, from o to 6, thus allowing it to be con­trolled with nicety. There is an automatic double rolling motion, which checks the board and the impression at the same time. By turning over a small lever which is directly connected with the inkers, these pass completely over the forme four times for each impression.

The platen is brought to rest to receive the impression on a broad seating, or shoe, and any variation in register is thus rendered impossible.

After being printed, a set of grippers, mounted on a swinging gripper shaft, lays hold of the sheets, takes theni to the delivery board and there deposits them, in a pile, printed side up, without risk of'smearing. The check, which is situated in a handy position for the feeder, is entirely novel. It acts silently, without bump or jar, and cannot be thrown in or out of action at the wrong time.

The Autofalcon Press

is the Falcon Safety Platen equipped with an automatic feeder. Instead of building the Falcon and feeder in one frame they are made as two units, which can be coupled together to make the complete machine. Thus the owner of a New Model Platen (any Falcon having individual grippers on the platen is a New Model) can have the press converted into an Autofalcon by purchasing the feeder. The feeder is self-contained and can be attached in a few hours, without the necessity of boring a single hole in the Falcon frames.

Hand feeding is not possible with most automatic feeders, yet on very short runs hand feeding is often both advisable and economical. The Waite Feeder has been designed so that by merely slipping a feed-board and plate into position the machine may be hand fed. Furthermore, the hand feed­ing is semi-automatic, it being only necessary to feed the sheet approximately instead of exactly to a drop roller and it is straightway conveyed by tapes and registered to gauges automatically. The hand feed is required for card and for a few papers which automatic feeders do not handle with full satisfaction.

The feeder is simple in construction and in operation, whilst readily adjusted to different sizes and classes of paper.

The Autofalcon Press, foolscap folio, is speeded at 4,000 per hour, and even 3,000 per hour in the royal folio size.

Protectors for Feeders. A variety of appliances have been invented for the purpose of preventing accidents to feeders, who carelessly or otherwise may fail to lift the hands before the platen reaches the bed, thus getting them crushed. The Factory Act includes provision for protection to workmen operating machines. This Act applies to platen presses, and all platen machines must be equipped with a guard to protect the hand of the feeder. Practically all the makers of these machines now attach a guard, and, although there are a few special and patented appliances adjustable to most makes of platens, more or less automatic in action, each of the engineers making machines of this type has devised his own form of guard. The invention usually consists of a con­trivance whereby the motion of the platen automatically thrusts the hand up out of the way.

CHAPTER III.

THE WORKING OF PLATEN MACHINES.

THE following instructions apply generally to the working of the several makes of machines of which mention has already been made, and which must be efficiently carried out if the highest standard of work is the aim of the operator.

Making Ready Type Formes. The following is the usual procedure for an ordinary job in movable type, such as a circular :—

First see that the bed is clear and free from dirt, also that ink duct, distributing, surface and rollers are perfectly clean. If not, they should be rubbed over with a piece of rag or waste soaked in turpentine or benzoline and then wiped dry with a piece of rag. The rollers are next placed in position. With an ordinary palette knife a little of the colour it is intended to use is spread upon the ink table and the machine let running. This is termed “inking up.”

Packing the Platen. Take one or two sheets of fairly stout printing paper, say, 54-1b. double crown, or its equivalent. Fasten them beneath the bottom clip and then place, next to the platen, a thin sheet of cardboard, also adding two or three sheets of paper ; draw the tympan sheets tight and firm and secure them under the top clip in the usual way.

Of course, if the type is much worn softer packing should he used. The board can be dispensed with and additional sheets inserted.

The forme is next examined to see that all the quoins are tight and that nothing is loose ; that the chase is not springing ; that it is properly planed and that no foreign matter adheres to the back. It is a prudent plan to brush the back and to plane again.

If everything is correct the forme is fixed in the bed. A proof may now be taken. on a waste sheet with very light impression. This will enable the machinist to ascertain the