PRESSES, PRINTINCI. The Hoe Rotary Art Press.—With the growth of magazines and the advance of their artistic character has come the demand for machinery capable of producing the highest class of illustrated work at great speed, and it is to meet this demand that the Hoe rotary art press, Fig. 1, has recently been constructed for the illustrated pages of The Century Magazine. This is the first machine ever made on the rotary principle and designed for the finest quality of illustrations, taking the place of the Hoc stop-cylinder presses, on which this grade of work has heretofore been done. The plates used are electro types of standard thickness, bent to the proper curve by a little machine furnished for the purpose. Each electrotype plate contains a page of the magazine and is locked upon curved blocks, which arc securely fastened upon the circumference of one cylinder. Sixteen form rollers, supplied with ink from two fountains, give the required amount of ink to the plates. The plates are inked with delicacy and fullness of color. The sheets of paper, each of the size of 32 magazine pages, are fed to the machine in the usual way, by hand, but by four feeders. The sheets are drawn between the impression cylinder and the plate cyl inder, receiving the impression.
After passing around the cylinders they are carried to the two fly deliveries, one above the other, each of which throws out two sheets of 16 pages each. The sheets conic out in four separate lots, those which each man feeds to the press being delivered in one compartment. The individual work of the feeder is thus accurately known.
It was a general belief not long since that the finest quality of illustrated work could be done only on hand presses, but the progress in the development of cylinder presses has made possible a high order of illustration at a much greater speed. The rotary art press has the capacity of four stop-eylinder presses, and is claimed to do even a higher quality of work than the stop-cylinder presses.
Cottrdes Improved two-color PPM is especially designed for bag printing in colors, and is applicable to many other styles and qualities of fine printing. The press is a two-roller drum-cylinder machine, to which is attached a supplementary cylinder of half the diameter of the drum. It is constructed to admit of curved stereotype or electrotype plates. and is furnished with fountain distributors, etc. There is also a patent device for controlling the momentum of the cylinder. In all cylinder presses (except the stop-cylinder) there is more or less backlash within the gearing, arising from the clearance of the teeth, and from the tendency of the cylinder to maintain its velocity while the bed is slowed down to pass the center. To obviate this, a patent device for controlling the momentum of the cylinder is
used. It cheeks the momentum of the cylinder at the right time. keeps the gears up to the working sides of the teeth, and harmonizes the regular velocity of the cylinder to the irregu lar velocity of the bed, relieves the gearing of all unnatural strain, and accurate register at any speed is thus secured. It consists of a brake-shoe attached to the framework and made adjustable at the box. The brake-shoe is adjusted to engage with the friction face secured to the cylinder shaft, with sufficient friction to gradually cheek the momentum of the cylin der at the proper time.
The Hoe Century Press.—The illustrated pages of a magazine form but a part of the work of its publication. There remain the plain forms and advertising pages to be pro duced, and the quantity of these is now so great that to continue to print them on the ordi nary cylinder press is no longer economical, indeed hardly practicable. To meet the new de mand, the century press has been built. The arrangement of this press (see Fig. 2) is similar to the Hoe fast newspaper press, but the plate and impression cylinders arc placed nearly on a level, and at a height that makes them easily accessible to the pressman. The distribution is effected by two large and two small ink cylinders for each fountain, with an adequate service of distributing rollers. The inking rollers are six in number, with an additional composition roller for cleaning the form. The plates used are electrotypes of the usual thick ness, viz.: of an inch, containing each one page of the magazine, and mechanically bent to the requisite press cylinder. The plates are each secured upon a curved iron stereotype block, locked up by a rack and pinion in the usual manner, and these curved blocks are in turn fastened securely to the surface of the plate cylinders, the pages being placed longitu dinally. The roll of paper is at the end of the press and is controlled in momentum by the usual hand brake. From it the web is drawn by tension in the usual manner through the printing cylinders, and is then cut into transverse sections, containing 8 pages on each side, or 16 on the two sides. These sections are gathered by a collecting cylinder• in pairs, one above the other; then receive a transverse fold between the two pages, and are sent alter nately to two delivery cylinders, where they arc slit longitudinally and delivered on two sets of traveling belts, in signatures of 8 pages each. The machine has thus a capacity of 8 signatures, or 64 pages, at each revolution, or 24,000 signatures per hour, cut and folded, ready for the binder.