When either of the forms is depressed, its distributing-rollers are carried to the ink-trough to receive ink from the supply-roller, which they transfer to the form by passing over its surface as it is elevated.
The paper to be printed is supplied to the machine from a feeding-board, through the medium of an endless web, passing over rollers, connected by bands or chains to the main shaft, which communicates, simultaneously, to all parts of the machine. The sheets of paper being placed on the feeding-board, a boy pushes them forward singly, when they are successively caught by the rollers and endless web, by being pressed down upon them through the medium of a projecting lever, operated upon at stated times by the motion of the machinery-When the sheet of paper is brought between the form and the platten, its motion, as well as the motion of the form, is stopped while the impression is communicated to it This stoppage of motion is effected without interfering with the motion of the main shaft, and other parts of the machinery, by removing the teeth from a portion of the circumference of the spur-wheel, which communicates motion to the web-rollers. After the first impression has been given to the sheet, it is carried about another roller, which turns its reverse side towards the platten, while the second or perfecting form is brought, by a vibration of the frame-work, under the paper to print the second side, or to give ill the perfecting impression, which is effected while the motion of the web-roller is stopped as before.
The platten is suspended over the centre of the press, and guided perpendiaularly down by strong frame-work, and the pressure is produced by a vertical rod, connected with the platten at its upper end, and with a revolving crank at its lower end; a lever with a counterpoise is also connected with the lower end of the vertical rod, which compensates for the weight of the rod and platten, while the two form-tables balance each other on the vibrating frame; and thus jarring irregularities in the motion of the machinery is prevented.
The second improvement consists of a printing press, or machine, with but one form-table, which is placed upon a frame, and made to vibrate between two plattens, placed in oblique positions, where impressions are given by each with such rapidity, that two or more feeding-boards, with the requisite web-rollers, are required to supply it with paper. This is a single printing machine, and there the sheet has to pass through it twice before the printing is completed. It differs, however, materially from the common printing machines; it having two plattens, and a form-table placed between them on a vibrating frame, instead of running forwards and backwards on wheels, as is the case with the printing machines employed at the Times' office, and other machines made by Applegath and Cowper.
Mr. Wayte's third improvement consists in a new arrangement of inking-rollers, by which he is enabled to diminish their number, and to effect a saving in the ink, by conducting the supply to such places only of the distributing-rollers as come in contact with the types: this is effected by causing the inking-rollers to pass over distributing blocks, which are made to correspond with the types in the form, and supplied with ink by a transferring roller; by this means the ink is supplied only to such parts of the rollers as come in contact with the types. This inking apparatus is equally applicable to the printing machines invented by Mr. Wayte, and to those of the usual construction.
Mr. David Napier, of Fitzroy Square, London, a manufacturer of printing machinery, of great ability and experience, specified a patent in 1831, granted to him for "certain improvements in printing and pressing machinery, with a method of economizing power, which is also applicable to other purposes." There are four inventions contained in this patent, all having reference to the printing business, and calculated to increase its facilities; we therefore subjoin a brief account of them.
Thefirst is a printing machine, of the kind called a perfecting, or that which prints both sides of the sheet before it is delivered from the machine. There are two forms of type placed on the same traversing stage, so far apart that the distance between them shall be equal to the length of one of the forms. The sheet of paper to be printed is conveyed to the forms by endless felts and guide rollers, in the manner usually adopted in the printing machines manufactured by Cowper and others. On the axes of the two rollers, which give the pressure to the paper while on the type form, are fixed two wheels, with teeth extending only half round, each of which takes into racks fixed on the side of the form stage. The diameter of these wheels is equal, and they are made exactly to correspond with the diameter of the rollers with which they move; they are connected together, and made to turn in different directions by means of a band passing over equal pulleys on each, and being so adjusted with respect to each other, that the teethed half of the one shall be upwards while the teethed part of the other is downwards; and thus they will take into their respective racks, and cause the form to traverse backwards and forwards alternately.
This arrangement will be better understood by inspecting the opposite diagram. a a represents the two cylinders which give the impression, with spur-wheel teeth on half the circumferences, as shown at b b. These teeth take into the racks c c, which being connected with the form stage dd, communicating to it reciprocating motion. The sheets of paper to be printed are receiving alternately from the feeding-tables at ef, and receive the first impression as they pass under the cylinder a; whence following the course pointed out by the arrows, they pass around and receive the second, or completing impression, in returning under the cylinder a, and are finally delivered on the receiving board g. The endless felts, tapes, and guide rollers, by which the sheets of paper are conducted, are not shown in the drawing, as they do not differ materially from those usually adopted for this purpose, hik and l represent a series of pulleys, by which the inking apparatus is put into operation.