A press with four impression cylin ders is capable of printing 10,000 rm pressions per hour. Four persons are required to feed in the sheets, which are thrown out and laid in heaps by self acting flyers, as in our ordinary cylinder presses. A press with eight impression cylinders will print 16,000 or more impressions per hour.
2. The Single Cylinder Printing Machine. In this press the form is placed on a flat bed, and the impres sion taken on the paper by a cylinder while the form is passing under it. The diameter of the cylinder is small, allow ing of compactness, and increases the number of impressions in a given time. One person only is required to feed it, and it gives from 2,000 to 3,000 im pressions per hour. The printed sheets are thrown out by a fly frame. By the addition of a register point appara tus it is rendered fit for book printing. It may be driven by hand or steam.
3. The Double Cylinder Printing Ma chine, has an arrangement similar to the foregoing, with the addition of ano ther impression cylinderich gives an additional impression the same form. Two attendants supply the sheets, which is all that is required for large edi tions, but where small editions are work ed off two boys extra are required to take out. A view of this press is given in the accompanying page.
4. Patent Single Large Cylinder Ma chine. In this the cylinder is of greater diameter than in any of the foregoing. It has a perfect register and sheet flyer, and adjustable bearers of iron, so that stereotype may be worked on it. One boy is required to feed, and it gives from one to two thousand impressions per hour. Man or steam power may be used. India-rubber impression cloths are used with these presses. An illus tration of this press is here subjoined.
5. The Little Jobber. This press com bines speed with durability. It is capa ble of throwing off 2.500 impressions per hour. it may be driven by the foot and treadle. The manner of running the bad is original, being accomplished by a crank and lever, which gives it a slow and uniform motion, while the impres sion is being taken, and a quick retro grade motion. The sheet-flyer is so ar ranged that no tapes pass round the im pression cylinder, no matter what the size of the form may be that is worked, and thus no tapes or fingers have to be shifted. It has iron feed and fly boards, and adjustable fountain, knife, and bearers.
The Patent Washington Hand Press, and the Patent Smith Press, are conveni ent forms of the bed and platen variety.
Messrs. Hoe have attached to these presses self-inking rollers, which may be thus described. The large distributing cylinder vibrates : there are two rollers to ink the forms, moving in a carriage with four wheels. The wheels on one end are plain, those on the other have a projecting flange in the middle of the rim. Two wrought iron rails are on the bed outside of the chase, one of them hav ing a groove cut in its top to receive the projecting flanges on one pair of the wheels, the other level on the surface. Projecting from ale distributor frame are two short rails, on which the wheels rest while the rollers receive ink from the distributing cylinder. The machine is set up behind the press so that the short rails on it shall agree exactly with the rails on the bed of the press, when it is run out, both in height and width. The brasses in which the inking rollers run, have regulated adjusting screws, so that they may bear more or less on the type as circumstances may require.