Untitled record

Outer cover for impression cylinder lifts The impression cylinder for rotary printing presses are provided with a lift of elastic material, and it is known, this lift of rubberized fabric, 'cork material o. The like. In one or more layers. or to produce leaves. In general, the outside of this elevator is provided with an oil-impermeable coating in order to avoid damage to the elevator by the fat ink. When transferring the elevators around the printing cylinder, the high tension of them easily damages the oil-proof coating material. Further, in the process of printing in the elevator, the types or printing form cause impressions and impressions which, at later prints, cause imperfections which disturb the clarity of the printing.

These disadvantages are avoided according to the invention in that a special, not firmly connected to the elevator top cover is placed on this, consisting of woven fabric layers with elastic layers, z. As rubber or synthetic resin, and on the effective surface has an oil-repellent coating. This top cover has a very small thickness, which is preferably not much larger than o, 6mm. When using such a top cover attack by the oil of the ink is avoided, and the blanket takes no impressions or impressions of the printing plate, so that the known lifts adhering üb.elstände be eliminated.

An embodiment of the printing blanket according to the invention is shown schematically in cross section on the enlarged scale. It consists of two layers ii and 12 of light and strong cotton fabric, which are cemented by means of an intermediate layer io of adhesive. This intermediate layer may consist of a conventional rubber cement.

Tissue layers ii and 12 are coincidentally coincidental and it is convenient to use aircraft grade A grade fabric as described below: Twisted mercerized yarn, plain weave, warp count 8o, weft 8o, weight 1 5 2.6 g , the square meter, minimum tear strength 36.29 kg on each way after the strip method, thickness 1 / i mm.

The rubber cement must be a firm and elastic layer which is not easily destroyed by contact with oil and solvents.

Without limiting the invention to the following ingredients and amounts, the following example of this rubber cement, which has given satisfactory results, is given here: Isautsclitik. , , , , , , , , , , , , , j 3,6o8 kg, zinc oxide. , , , , , , , , , , , , 11.567 kg antimony sulphide. , , , , , , , , , , , 2,375 kg .: sulfur. , , , , , , , , , , , 1.361 kg, aldol-alplia-naphthlivani .. 0.1701: g, lime. , , , , , , , , , , , , , , , o, 17o kg, diplienylguanidine. ,. , , , , , , o, 153 kg, stearic acid. , , , , , , , , , , , , o, j_12 kg. The mixture indicated in this example is preferably dissolved in a suitable solvent, such as gasoline, and the mass is then applied to the Geivebest @ offschicliten 1 i and 12 by the known Spreading process, whereby the putty is applied in a series of thin layers. Enough solvent is added to make the cup dispensable.

The putty can be applied to the fabric layers ii and 12 by means of a calender, but a uniform thickness can be achieved with certainty by brushing.

After the putty is applied to a surface of each of the two fabric layers 1 i and 12, the coated surfaces are compressed by performing the layers i 1 and 12 by rolling. The total thickness of the two fabric layers ii and 12 and the intermediate layer io must be about 1; smin less than the desired thickness of the final product. For most purposes, the desired thickness of the final product is from -1/5 to 3/1 mm. The thickness of each fabric layer may be about 1/4 "and the thickness of the intermediate layer about 1/4" as the material passes through the rolls.

Instead of using rubber, any other putty can be used, which has the desired elasticity, flexibility and strength. So z. Certain synthetic resins, such as phenol-formaldehyde condensation products, and the resins formed by the action of glycerol on phthalic anhydride are used. It is also possible to use the synthetic, rubber-like product described in US Pat. No. 1,829,502, which is a polynier of the di-vinyl-acetylacetate. Then, a surface coating 13 is applied to one of the fabric layers. This surface coating inuß flexible, elastic. 4.z@h and be oil repellent. Preferably, a surface coating is used which consists essentially of a reaction pad obtained by the action of ethylene dichloride on sodium polysulfide. Other similar coating materials can be used, which are formed by the action of halogen-substituted olefins on alkali metal polysulfides.

Likewise, other coating materials may be used which have a base of nitrocellulose, cellulose acetate, phenol-formaldehyde condensation products or resins formed by reaction of glycerol and phthalic anhydride. Also, oxidized linseed oil u. Like. Be used.

The general process for the preparation of this surface element is described in the German Patent 6oo 5 ¬ 3.

Preferably, after being prepared and cooled, the blanket is passed through a polishing and smoothing machine. This machine basically consists of two drums that rotate at high speed. One of these drums is covered with fine abrasive cloth or some other abrasive or cleaning material and the other drum is covered with felt or other suitable polishing material. The finished and cooled blanket is pulled through this machine under tension several times until all surface coating defects have been eliminated and a smooth and highly polished finish. Surface is formed.

In the finished ceiling, the thickness of the surface lap is equal, so that the finished article has a total thickness of 3/5 mm.