US1810470A - Intaglio printing machine - Google Patents

Description

June 16, 1931.

A. EGLI INTAGLIO PRINTING MACHINE FiledJuly 20, 19?

I bu anion Patented June 16, 1931 UNITED STATES PATENT OFFICE ARNOLD EGIII, OF HAMBURG, GERMANY INTAGLIO PRINTING MACHINE Application filed July 20, 1928, Serial No.

It is generally necessary in intaglio-printing-machines, especially for intaglio-sheetprmtirig-machines, for the printingand impression-cylinders to be separated very 6 quickly by a distance of about in. in order to allow the passing of a sheet or portion of a web without its being touched by the printing-cylinder 01' printed by it. i

It is known how toshift the printingl cylinder in the direction of pressure of the 'will be visible in the difference of tinge of the sheets being printed and is therefore very objectionable. t

This undesirable efi'ect is less noticeable in single colour-printing-machines, as an interruption of the printing-process occurs very seldom, but it would be practically impossible to produce a multiple-colour-intaglio-printing of good quality because'of this effect, since after every printing-operation of the machine one or more stops are necessary.

Besides the foregoing other intaglio-printing-machines are known,-where the printingcylinder with the scraper belonging to it can be shifted in radially arranged wings towards the impression-cylinder and away from it. The purpose of this device is to interrupt the printing upon an endless paper-band, to which the colours are transferred from the rubber impression-cylinder by means of several colour-inking rollers similar to oftset-printingin order to terminate the work of the machine.

The problem however of producing a mul tiple-coloured intaglio-printing cannot be solved by means of such a device, as intaglioprinting is a. printing process which, because of its peculiar character, requires absolute accuracy. If, for the purpose of guiding the printing-cylinders, wings are arranged in the well known manner, the guiding otthe stone-blocks in the wings supporting the printing-cylinders must work so 294,272, and in Germany July 28, 1927.

easily, that the required velocity of the shifting-movement is actually attained; such guiding can however, be eifected only by a relatively large play between the stone-blocks and the wing-guides. This great play causes great inconveniences in intaglio-printing on account of its fineness, as a completely obliterated print is produced. It now instead of loosely guiding the moving mechanism, strong forces are applied not only are knocks produced but, on account of the strong friction of the parts working against each other this play and therewith the before mentioned disadvantages again appear.

The invention about to be described does away with these disadvantages by providing a novel mounting for the printing-cylinder, which moves towards and away from the impression-cylinder, such printing-cylinder according to the invention being journalled in supporting plates which are swingable about a rotary pivot, the latter being in substantial ly vertical alignment with the center of the cylinder. Because of the small friction areas at the pivot of the supporting-plates only small 'forces need be exerted for oscillating the printing-cylinder in spite of the tact'that the pivots are mounted in the bearings without play. When each pivot is arranged in a vertical line. passing through the center of gravity of the associated printing-cylindersystem, the latter can be moved through comparatively large angular displacements with out raising or lowering such center of gravity to any considerable extent, in consequent of which practically no more power is needed for oscillating the printing-cylinder toward and away from the impression-cylinder than is necessary to overcome the friction at the rotary-pivot-bearing. If the pivot of the plates in the vertical line through the center of gravity of a printing-cylinder-system is arranged below the center of gravity the system being then in unstable equilibrium as it is balanced upon the pivot shaft, a further advantage is obtained in that when the printing-cylinder-system is swung out of its os1 tion of unstable equilibrium only part 0 the distance to. the impression cylinder, the,

weight of the printing-cylinder-system itself" ice acts to move the system for the rest of such distance in consequence of which less power for the shifting action is required.

A further advantage flowing from the use of pivoted supporting plates mounted on rotary pivots in accordance with my invention lies in the fact that the scraper as well as the inking-roller can be arranged on such plates, in consequence of which the scraper and the inking-roller are oscillated together with the printing cylinder, thereby. preventing any change in their relative positions. The printing cylinder is thus engaged with a constant and uniform pressure by the scraper, regardless of whether it is in the printing position or has been moved away from the impression cylinder. The-inking-roller is likewise kept at a uniform distance from the printing cylinder, so that the inking action is not influ enced in any way. p Y

A preferred form of the invention is illustrated diagrammatically-by way of example in the accompanying drawing. As shown on such drawing, a rotary pivot (g) is arranged substantially vertically below the shaft (a) '2 of the printing-cylinder (6). U n this rotarypivot (q) supporting-plates d) are journalled to swing-out and receive the shaft 3a) of the printing-cylinder (b) the bearings e) of the scraper-holder (f) and the adjustable bearings (g) of the inking-roller (k).

Because of the fact that the pivot (a) is arranged perpendicularly below the shaft ((1) of the printing cylinder (6),. the center of gravity of which, in consequence of the preponderating weight of the printing cylinder, has nearly the same position as the center of vity of the printing cylinder, scraper and inking-roller system, the entire load of the system is supported by the pivot, so-that to move or oscillate the platesand the mechanism supported therehy only the friction of thepivot (a) must beovercome. Immediately after the movement of the printing cylinder, scraper, and inking-roller system out of the position of unstable equilibrium has started, the weight of the system acts to overcome a part of the friction forces existing on the clrcumference of the rotary pivot (a) and frames-on their pivots to move the printing cylinder alternately toward and away from the impression cylinder, the pivotal axis of said plates being in substantial vertical alignment with the center of gravity of the mass mounted on said pivots, whereby oscillation of the printing cylinder toward and away from the impression cylinder is effected without appreciably raising orlowering said cen-" ter of gravity, and the power required to move said printing cylinder is reduced. 7 Y

2. In an intagliov printing machine, in combination, an impression cylinder, a pair of carrier frames pivoted adjacent to said cylinder, a printing cylinder journalled in said carrier frames, and means for oscillating said frames on their pivots tomovethe printing cylinder alternately toward and away from the impression cylinder, the pivotal axis of said plates being in substantial vertical ahgnment with and located below the center of. gravity ofsaid printing cylinder, whereby oscillation of the printing cylinder toward and away from the impression cylinder is effected without appreciably raising or lowering said center of gravity, and the power required to move said printing cylinder is reduced. v

- 3. In an intaglio printing machine, in combination, an. impression cylinder, a air of carrier frames pivoted adjacent to sai cylmder, a printing cylinder journalled in said car-- rier frames, an inking roller and a scraper likewise mounted on said frames, and means for oscillating said frames on their pivots to move the printing cylinder alternately toward and'away' from the impression cylmder, the pivotal axis of-said plates bein in substantial vertical ali ent with an located below the center 0 gravity of the printing cylinder, inking roller and scraper, whereby oscillation of the printing cylindertoward and away from the impression cylinder is effected without appreclablyraising or lowering said center of gravity, and the power required to move said printing cyhnder 1s reduced. I I

In testimony whereof I have hereunto set in hand.

y ARNOLD EGLI.

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