US2233357A - Printing mechanism and impression cylinder therefor - Google Patents

Description

Feb. 25, 1941. F. G. BREYER 7 2,233,357

PRINTING MECHANISM AND IMPRESSION CYLINDER THEREFOR Filed July 11, 1940 10 20 gf K G. BREYEQ ATTORNEYS Patented Feb. 25, 1941 PATENT ()FFICE PRINTING MECHANISM AND IMPRESSION CYLINDER THEREFOR Frank G. Breyer, Wilton, Conn., assignor to J M. Huber, Inc., New York, N. Y., a. corporation of New Jersey 7 Claims.

This invention relates to printing apparatus intended particularly for use in the practice of the recently-developed cold set printing process described in a co-pending application of Walter Huber, Serial No. 288,113, filed August 3, 1939.

In the practice of said process, the inking rollers and printing form of each printing mechanism must be heated to elevated temperatures substantially above the melting range of the nor- 1 mally solid thermo-fluid ink to be printed. For high speed newspaper printing, such as at web speeds of 600 to 1500 linear feet per minute, I have found it advantageous to use printing temperatures well above 210 F., as set forth in my co-pending application, Serial No. 344,885, filed of even date herewith. When using such elevated printing temperatures, however, heat exchange between the hot printing form of each printing mechanism and the surface of the adjacent impression cylinder tends to raise the temperature of the latter to such a point that it becomes somewhat plastic. The usual printing press impression cylinder is formed with layers of elastic cushioning material supporting a top or surface sheet of rubber or other thermoplastic material. Excessive heating of this thermo-plastic material, together with the constant impact and deforming pressure of hot printing surfaces thereagainst during printing operations, has been found to result in such indentation or marring of the impression cylinder surface that printing results are seriously impaired. This difficulty has been particularly evident when printing with high speed newspaper presses in which the impression cylinders are constantly held close to the heated printing cylinders and consequently tend to become quite hot.

An object of my present invention is to provide new and improved printing apparatus and new impression cylinders therefor whichcan be used without diificulty in printing according to said cold set process. Another object of this invention is to provide a new impression cylinder 15 construction which possesses the required elasticity or cushioning action and at the same time resists heat and remains smooth and uniform in surface qualitiesover long periods of use at elevated printing temperatures.

I have dlscoveredthat the difficulties encountered with impression cylinders of known construction can be avoided and that the cold set printing process can be, carried out with improved 'results by providing each printing mechanism with an impression cylinder having a special cov- Application'July 11, 1940, Serial No. 344,886

ering of very finely woven, heat-resistant fabric. In preferred embodiments of my invention this covering consists of a finely-woven fabric such as balloon cloth, which, if desired, may be provided with a thin coating containing aluminum 5 powder. The ballon cloth covering may be applied to the cylinder as part of a laminated top sheet consisting of layers of balloon cloth enclosing an intermediate thin layer of rubber or other suitable. cushioning material, which top 10 sheet is drawn tightly over an elastic supporting structure comprising laminations of coarser fabrics and cushioning materials of the kinds usually employed as supporting blankets in the construction of printing press impression cyl- 15 inclers.

The finely woven cloth surface of the new impression cylinders resists indentation or deformation during long periods of service at printing temperatures as high as 230 F. and higher. This 20 result is achieved even though the cloth surface be positioned next to a thin layer of rubber or rubber-like material, as the latter is enclosed between and protected by balloon cloth layers. The tightness and finely woven quality of the bal- 25 loon cloth strands prevent them from being spread by the pressure of small half-tone dots or other small printing characters carried by the hot printing form, and the balloon cloth I or the like presents a smooth impression surface 30 free from irregularities or level variation that would adversely affect printing quality. Notwithstanding these characteristics, the covering fabric yields under the pressure of the printing surfaces and thus prevents the latter from dam- 35.

aging the paper web during printing operations. In addition, the fabric is resistant to water and oil, even at elevated temperatures, so that the new construction can be used to advantage whenever a spray of water-oil emulsionor other suit- 40 A to reveal the composite construction; and 55 Figure 3 is an enlarged fragmentary cross section through the periphery of th impression cylinder.

Referring to the drawing for details of the illustrated embodiment, Figure 1 shows one printing mechanism of a high speed rotary letterpress such as may be used for high speed newspaper printing according to the cold set process. A printing cylinder P and an impression l cylinder S are arranged side by side in closely spaced relation. The printing cylinder carries a printing form F, usually consisting of stereotype printing plates. The printing form rotates in contact with inking rollers I, which form parts of an inking mechanism (not shown) that feeds molten thermo-fluid ink from an ink furnisher and distributes it evenly onto the relieved printing surfaces of the rotating form. The printing cylinder P, as shown, is made hollow and is heated to elevated printing temperatures by circulation of hot water therethrough. The water heating system is not shown in the drawing because it forms no part of the present invention.

The web A to be printed passes through the bite between the printing cylinder P and the impression cylinder F and thence over a cooling roller C, which is held at a suitably low temperature by 'intemal circulation of cold water. As the web travels between the two cylinders it is impressed with films of molten thermo-fluid ink carried on the printing surface of the form F. The hot molten ink films so printed adhere to the web and freeze to a solid condition by loss of heat into the web immediately upon leaving the printed surfaces. Their final solidification to a hard, mar-resistant condition is effected by the chilling action of the cooling roller 0.

The impression cylinder S, as shown more fully in Figure 2 and Figure 3, comprises a rigid cylindrical core I 0 which is surrounded by lamina- 4 tions 20 and 30 of elastic cushioning materials and covered tightly by a top sheet 40 having a surface fabric of balloon cloth or other similar v thin, finely-woven fabric.

In the illustrated embodiment, as shown in Figure 3, the lowermost lamination 20 consists of coarsely woven fabrics 22 and 24 enclosing anintermediate layer 26 of rubber or rubber-like composition. The next lamination 30 consists of coarsely woven fabrics 32 and 34 enclosing a layer 36 of cork composition or the like. The top sheet 40 consists of two layers 42 and 44, each of balloon cloth, and a thin ermediate layer 46 of rubber or rubber-like c mposition. As an example only, the thicknesses of laminations 20, 30 and 40 may beabout .062", .062" and .025", respectively. The stipling on the face of the top sheet 40 in Figures 2 and 3 is intended to indicate the presence on the outer Balloon cloth layer so 44 of a thin protective coating containing aluminum powder. I

It will be understood that the blankets underlying the top sheet may be made of various types of cushioning materials and may be arranged in any number, order or thickness as long as the required elasticity orcushioning effect is obtained. The important feature is to utilize the surface characteristics and heat resistance of the balloon cloth covering, which provides a smooth, uniform, yieldable impression surface and protects the impression cylinder against damage formerly caused by high temperature conditions i in conjunction with the impact and pressure of 5 hot printing surfaces thereagainst at high printing speeds. It will also be understood that other finely-woven cloths having similar qualities may be used in place of balloon cloth, and that various types of protective coatings may be used on 1 the surface cloth. Indeed, the use of a surface coating may be dispensed with altogether with-' out departing from the broader contribution of this invention.

It will therefore be apparent that the inven- 15 tion should be accorded a scope commensurate with its novel contributions to the art, as intended to be set forth in the appended claims, without restriction to non-essential details of the illustrated embodiment. 2

I claim.

1. A rotary printing mechanism for printing molten thermo-fluid ink comprising a printing cylinder, heating means therefor, and an impression cylinder adjacent thereto having a covering of smooth, finely-woven, heat-resistant fab ric.

2. A rotary letter-press printing mechanism for printing molten thermo-fluid ink comprising a printing cylinder adapted. to carry a printing 30 form, heating means therefor, an impression cylinder adjacent thereto having a covering of smooth, finely-woven, heat-resistant fabric, and an elastic backing for said fabric yieldable under pressure from said form.

3. A rotary letter-press printing mechanism for printing molten thermo-fiuid ink comprising a printing cylinder adapted to carrya printing form, heating means therefor, an impression cylinder adjacent thereto having a covering of smooth, finely-woven, heat-resistant fabric, and an elastic backing for said fabric comprising laminations of fabrics and cushioning materials.

4. A rotary letter-press printing mechanism for printing molten thermo-fluid ink comprising a r printing cylinder adapted to carry a printing form, heating means therefor, and an impression cylinder adjacent thereto having a tight covering of balloon cloth supported by an elastic backing. I

5. An impression cylinder for a printing press or the like comprising a rigid cylindrical core, elastic cushioning materials surrounding said core, and a covering of smooth, finely-woven, heat-resistant fabric. I

6. An impression cylinder for a printing press or the like comprising a rigid cylindrical core, a plurality of laminations of fabrics and elastic cushioning materials surroundingsaid core, and a tight covering sheet over said laminations having inner and outer layers of balloon cloth and an intermediate thin layer of elastic cushioning material laminated thereto.

7. An impression cylinder for a printing press or the like having a surface of balloon cloth with a thin coating thereon containing aluminum powder.

FRANK G. BREYER.

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