US2689523A - Moistening device for the plate cylinders of printing presses - Google Patents

Description

2 Shets-Sheet l W. KOCH y MOISTENING DEVICE FOR THE PLATE CYLINDERS OF PRINTING PRESSES Sept. 21, 1954 Filed April 4, 195o Sept. 21, 1954 w. KOCH 2,689,523

MoIsTENING DEVICE FOR THE PLATE CYLINDERS 0E PRINTING PRESSES Filed April 4, 1950 2 Sheets-Sheet 2 In venan- Patented Sept. 21, 1954 MOIS TEN IN G D EVICE FOR THE l PLATE CYLINDERS OF PRINTING :PRES SE S Werner `Koch, Offenbach am MainGermany, as-

signorto Faber &"Sc'hleicher Aktiengesellschaft, Offenbach am Main, Germany, a, firm Application April 4, 1950, 'Serial No. 153,937

'Claims priority, 'application Germany April 9, 1949 2 Claims. l l

This invention relates to a device for applying liquidto surfaces and'isintended more especially for use in lithographie printing machines, in which it more particularly refers to the means provided in such or similar machines for moistenlng the plate cylinders-thereof. It is tobe understood'however, that in some of itseaspects the invention is not limited to machines or devices of the particular kind -referred `to but may `be applied to anyother machine or `mechanism in whichthe process or the means constituting this invention may be found advantageous.

`It is one of the objects of 'this inventionto improve the` methodandithe meansfor carrying out such moistening `of surfaces, particularly moving surfaces-as have `hitherto been'in use `and to en` able a better taking up and amore uniform or efficient spreading of the liquid upon `the said surface. i

The invention further provides waysand means to :afford such improvements in a novel, variable manner and to lsuit varioustypes-of surfaces/and devices, and with these `and vother objects in viewlitconsists in Aa new and useful `arrangement of parts and -inthe'mannerof their-application or use as Lwill lbe-v hereinafter described and pointed i out inthe claims.

Inlithographic printing machines fit is customary to meisten the printing `platecylinders bythe use of a`moistening device, in which a metallic cylinder isn-adapted 1Ato Aevenly or intermittently rotate in fa -water freceptacle. The water contained in the receptacle is caused to be carried up bythe rrotation of this cylinder and transferred toa fabriccoveredoscillating rollenwhieh contacts the cylinder at certain .predetermined intervals, kand transmitted to a systernof distributing rollers 'which eventually apply Ithe moisture/thus received 'onto the printing plate.

Regulationlof the quantity of liquid to be applied in `these known devices may be carried out in Avarious ways, as for Linstance by altering the space through which the circumference of the cylinder passes during the time of one printing operation, or, in the case of an evenly rotating cylinder, by varying the time of contact between the take-up roller and the said cylinder.

With these known devices difliculties arise particularly in connection with high-speed printing presses partly owing to the fact that the alterations in the diameter of the take-up roller, which in practice cannot be avoided, renders a shockless starting` of the oscillatory movement of the said roller impossible, and partly because of the necessity of suddenly bringing the rotary speed of (Cl. Vlill-147) the 'take-up roller from thespeed offmovementof theplate to the just prevailing speed of rotation of the cylinder, and vice versa.

In order to avoid these disadvantages it has been proposed to apply the required moisture both totheplate andthe distributing rollersby means of suitable nozzles adapted to eject water under great pressure. It has further been proposed to spray Athe moistening liquid by means of compressed airincooperationlwith mechanical means such as rotary brushes or high-speed toothed gearing.

However, -n'either o'f these known `meistening deviceshas been able-to satisfy the -practical requirements, i partly -`on vthe score of unreliability and partly because of their failure `to permit-of adequate regulation.

The process which-forms one part of my invention has for `its main object to remove these disadvantages and for Athis vreason consists in the continuous formation of numerous small pads or dabs of liquid, to convey sameto their places of application and to precipitate them at a given moment :against the surface or surfaces 1to be moistened.

Ithas beenlfound practical 'to produce thesaid- 'pads of `l'iyuidby passing a revoluble liquid carrier ofA suitable formation :through the liquid contained 4.in "a :receptacle fand blasting them at the given 'moment by a draft of airolforthrough` the carrier against' the-platen. Instead of immersing the Vcarrier vin i or passing it through the liquid, the Lsaid pads `may be Vcaused to :form by the liquid l being sprayed upon the carrier.

The device for carrying out my "invention, which serves to form the said pads of liquid and to apply them "to the surface -to `be moistened, preferably and mainly consists `oi-a radially perforated hollow cylinder adapted to rotate in a bath of rliquid-and in the interior Vof which an elongated nozzle for the ejection ofthe compressed air is arranged. The distance: of the cylinder from the surface to be moistened is preferably adjustable. It is further suitable to provide between the cylinder, or the air nozzle respectively, and the surface to be moistened a shield or fender, which is preferably also adjustable in position as by means of a lever and set-screw arrangement, and by means of which part of the air blast may be warded off so as not to become effective.

A device suitable for carrying the invention into effect will now be described with reference to the accompanying drawings in which the new moistening device is illustrated by way of example.

In these drawings,

Fig. 1 is a cross section through a device in accordance with the invention.

Fig. 2 is a top view, partly in section, thereof.

Fig. 3 shows a detail.

In the example illustrated in these drawings a hollow cylinder I'I, which is adjustable preferably by a block 24, which can be raised and lowered within a vertical slot in the frame 23 of the machine by means of a screw 25 and nut 26, toward and away from the surface to be moistened, is employed. This cylinder, the axis of which runs parallel to that of the plate cylinder I, is provided with radially disposed perforations and adapted to rotate at regulatable speed in a liquid bath I8. Within the cylinder I'I is a nozzle I9 extending preferably over the entire length ,of the cylinder and through which compressed air is blown through the perforations in the cylinder against the surface to be moistened. When dipping into the liquid contained in the receptacle I8 the radial perforations of the cylinder are iilled with little pads of liquid which, by the rotation of the cylinder, are conveyed to opposite the orice or spout of the nozzle I9. The blast of air issued from the said nozzle now causes the small pads of liquid to be blown out of the perforations and to be thrown against the plate cylinder, to be distributed by the application roller 2 which, for the purpose, is provided with a felt sleeve 3.

The quantity of liquid applied can be regulated either by altering the speed of movement of the cylinder or by altering the air pressure or the velocity of the air respectively. Instead of causing a uniform ow of air through the system, the air may be blown intermittently through the perforated cylinder in which way it will be possible to regulate the degree of moisture applied with the speed of the cylinder remaining constant. Instead of blowing the pads of liquid directly against the cylinder I, they may be directed against the roller 2, 3 and transmitted from this roller onto the plate cylinder I.

In a preferred form, however, the regulation of .the quantity of liquid to be applied to the plate cylinder is effected by partially shielding oi the air blast, or both air and liquid respectively. For this purpose a shield or fender 2I is pivotally mounted in arms 20. By the turning of set screws 22 the upper edge of the shield 2l is moved more or less into the stream ejected from the nozzle and the perforations and, thereby, shield off part of the yliquid emanating from the moistening means. Y

I-Iavingl now described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a moistening device for moistening the plate cylinders in printing machines, a plate cylinder, a liquid receptacle, a hollow cylinder revoluble in said receptacle adjacent said plate cylinder about an axis parallel to the axis of said plate cylinder and with its lower part submerged in the liquid, radial perforations in the wall of the said cylinder of a kind to take up from the receptacle dabs of liquid and to carry them around during the revolution of the said cylinder, a take-up roll for spreading the liquid over said plate cylinder, a compressed-air nozzle Within the cylinder adjacent its inner wall and delivering directly through the said perforations to thereby blow the said dabs of liquid against the plate cylinder, an adjustable shield for screening 01T parts of the ejected liquid, a springcontrolled two arm lever pivoted to the axle of said cylinder carrying said shield upon one of its arms and a bearing surface for cooperation with an adjusting member on the other, and means for adjusting said cylinder together with its nozzle and screening device in relation to the said plate cylinder independently of the said liquid receptacle.

2. In a moistening device for moistening the plate cylinders in printing machines, a plate cylinder, a liquid receptacle, a hollow cylinder revoluble in said receptacle adjacent said plate cylinder about an axis parallel to the axis of said plate cylinder and with its lower part submerged in the liquid, radial perforations in the wall of the said cylinder of a kind to take up from the receptacle dabs of liquid and to carry them around during the revolution of the cylinder, a compressed-air duct concentrically arranged in the said cylinder and stationary in relation thereto, an elongated air nozzle forming part of said air duct and positioned adjacent the inner wall of the revoluble perforated vcylinder to directly blow said dabs of liquid through the said perforations against the plate cylinder, a take-up roll in rolling contact with said plate cylinder for spreading the ejected liquid over the plate cylinder, a spring-controlled lever pivotally arranged on the compressed-air duct outside of the cylinder a shield supported on said spring-controlled lever, a screw and nut arrangement in cooperation with said lever for pivotally adjusting said shield in relation to the nozzle, and means for moving the spraying device in a direction toward and away from the plate cylinder independently of the liquid receptacle.

References Cited in the le of this patent UNITED STATES PATENTSV Hauser et al Dec. 23, 1952

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