DE3004295A1 - FLUID ROLLER - Google Patents

Description

description

The invention relates to rollers, in particular to liquid rollers with a hard surface and gaps provided therein.

The transfer of liquid by means of cylindrical rollers has long been known. The training of the The roller often depends on the area of application, the viscosity of the liquid to be applied and the operating speed and similar parameters. In the printing industry, fluid rollers are used for a variety of purposes used, for example, in color systems, color is supplied via inking rollers; Well solution is used in humidification systems fed via rollers; Coatings, pigments and dyes are applied instantly with the help of rollers applied to paper or fabric or similar webs. The application of liquid rollers is with it only outlined by way of example, and it is only used in the following to simplify the description of the printing technology spoken. However, this does not mean a limitation of the invention, which of course also applies to the transmission of others Liquids on other substrates with different viscosities is suitable.

In large lithographic printing presses, fluid wetting and ink application usually take place. Thieves-

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wetting system requires a controlled supply of wetting fluid by a plurality of rollers arranged in the press. The fluid supply must be controlled Speed, controlled application thickness and controlled Uniformity in order to achieve a sufficient quality for the print and streaks, color gradients, To avoid lubrication points and other negative influences. The controlled fluid transfer is, however A problem not only for lithographic printing, but also for other fields of application as well as difficulties for different roller shapes.

One of the greatest problems in offset lithographic printing is the application of the dampening fluid the surface of the lithographic printing plate, and it is difficult to obtain equal amounts in a more uniform manner Apply in a manner that is necessary for a consistently good reproduction quality of the image printed on the paper is. A lithographic printing plate is a chemically treated metal plate that holds the printing surface is prepared for the absorption of color, while the areas not intended for printing are hydrophilic or are capable of absorbing moisture. For the printing process, a thin layer of wetting fluid is applied to the surface applied to the pressure plate, which is

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phile areas, but is repelled in the pressure areas. This allows the print areas to color while the non-printing areas are separated from the ink by the wetting layer.

Numerous rollers for printing technology are already known, for example polished, chrome-coated wetting rollers for lithographic wetting (U.S. Patent 3,259,062). Similar rollers are from the US patents 3,647,525, 3,508,489, 3,168,037 and 3,433,155 are known. The well-known chrome-coated rollers have a smooth, polished and chrome-plated surface that is very special in terms of its surface properties is hard and which is very soft for easy application of a fluid layer. Chromium-coated, hydrophilic Transfer rollers are therefore widely used in the printing industry, although they have certain disadvantages. So For example, a wetting agent such as alcohol must be present in the wetting solution. Through the Alcohol reduces the surface tension of the network fluid, so that it is evenly distributed over the polished, homogeneous surface of the roller. Because alcohol however, is extremely expensive and becomes more expensive as the oil shortage increases, this presents a significant disadvantage represent.

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A roller with a rough surface is also known from US Pat. No. 3,285,169. There are also rollers with rougher Surface known whose surfaces are soft; however, the latter have not caught on. With the known hard, rough roller, which is referred to as the so-called "anilox" roller, allows greater fluid layer thicknesses apply than with smooth rollers. However, they also have certain disadvantages and that is their surface Easily damaged due to the fact that it is made of copper with a surface coating. Also, often sits down Paint in the deep cracks of the "anilox" roller. Further disadvantages of the known rollers are in the Surface friction, the tendency to form emulsions, fluid turbulence and the resulting Unevenness of transmission. The rough hard or soft rollers were therefore replaced by the smooth, Polished, hydrophilic rollers with hard surface replaced, which however also part of the advantages of the rough rollers was lost. The same is true of other, industrially used rollers, and it does exist hence a strong need for better liquid transfer rollers.

Wherever there is a transfer of liquid through rollers rotating at different surface speeds, this is often the case with controlled processes

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is the case - the surface shape of the rollers has a direct influence on the amount of energy expended for the rotation. So owns a rough roller that deals with at a different speed than an adjacent roller rotates, a higher frictional resistance. Require hard polished rollers therefore, in general, less propulsive energy when facing one another at a different speed Turn the rotating roller that is pressed in at the same time. If highly viscous liquids, e.g. polymer coatings, transferred, the surface friction is even greater, and there is an increased need for improved transfer rollers.

It is therefore an object of the invention to provide an improved roller that has both the advantages of a rough Roller combined with the advantages of a smooth, polished roller. The invention provides such a roller, which largely avoids the disadvantages occurring in the prior art and because of its surface design facilitates fluid transfer. This is achieved by being etched into a very hard surface with great precision Surface gap reached. The result is the unevenly polished surface and the connecting gaps a significantly improved fluid transfer while avoiding the disadvantages occurring in the prior art.

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The measures specified in the characterizing part of the main claim are used to solve this problem. This provides an improved fluid roller having a hard metallic surface around a cylindrical core which is rotatable in contact with a fluid supply roller. Irregular gaps are provided in the surface of the roller. The gaps take up up to 30 % of the surface of the roller and form an irregular pattern. They are interconnected and allow the fluid to flow crosswise and to mechanically break the surface tension to facilitate greater transmission capacity.

The invention also relates to a method for producing a metallic fluid roller from a cylindrical core, which is characterized in that the cylindrical core is provided with a metal jacket which is then etched to achieve an irregular gap pattern. The webs remaining between the gaps are polished, whereby gap depths of 0.025 to 0.05 mm are formed. The gaps take up to 30 % of the surface of the roller.

In a further development of the invention, the chrome-sheathed, cylindrical core is etched and polished to produce a result in an irregular split pattern that is 10 to 17%

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occupies the surface and the gaps are up to 0.25 mm deep before polishing. The one between the columns remaining islands are finely polished to 8 RMS. The roller is as a fluid transfer roller together with a Fluid supply, for example a trough, and an application area, for example a web, can be used, if devices for applying fluid under pressure are provided; this is, for example, a second roller with a soft surface that is pressed against the transfer roller. The uneven distribution of the gaps the roll according to the invention allows lateral distribution of the fluid in the gaps, and as a result, larger amounts of fluid can be transferred than with smooth rollers.

The invention is explained in more detail below with reference to figures; show it:

Figure 1 is a perspective view of a fluid transfer roller;

FIG. 2 shows an enlarged section through the surface of the transfer roller according to FIG. 1, showing of an implementation of split patterns;

Figure 3 is an enlarged plan view of the surface of the roller according to Figure 1 showing a Split pattern;

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FIG. 4 shows another embodiment of the gap pattern according to FIG. 3; and

Figure 5 is an enlarged side view in section through the roller according to Figure 1 showing the Fluid transfer.

Figure 1 shows a fluid roller 10, which is attached to a second Roller 12 is pressed and this presses for easier fluid transfer. It can be seen on the fluid roller 10 a gap pattern 14. The gap pattern 14 is in a hard outer cylindrical surface 16 of the fluid roller 10 in Shaped in the manner described below and gives the roller a certain, non-coherent, non-homogeneous Surface. When working with the roller, the nip pattern does not give the fluid roller 10 all of the benefits interrupted, smooth-polished roller and a rough, knurled or "anilox" roller without both of them Has disadvantages. The outer surface 16 is hard and impenetrable to impact, while at the same time Depressions in the form of the gap pattern 14 are present.

FIG. 2 shows an enlarged, sectional side view of the outer surface 16 and the gap pattern 14 of the fluid roller 10 according to Figure 1. It can be seen that the gap pattern 14 from a plurality of interconnected, in the

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Outer surface 16 is formed columns 18, which are in a generally predetermined depth and width in the outer surface 16 extend. Between adjacent columns 18 there are polished islands 20 which form the surface of the Form fluid roller 10. The islands 20 are separated from one another by the irregularly extending gaps and permit a fluid flow around it. In this way, the outer surface 16 of the fluid roller 10 has a discontinuous, inhomogeneous surface compared to applied fluids. On the surface either static or Dynamically applied fluid initially has certain flow properties that depend on the type of surface, i.e. smooth or rough, are independent. For example, if a drop of water is applied to a known roller, then it generally clumps together unless it has been previously treated with a wetting agent to reduce its surface tension has been treated. If the same drop of water on the outer surface 16 of the invention Fluid roller 20 applied, then it spreads as if a wetting agent had been added, because the each other connected column 18 break its surface tension mechanically. This also occurs when the Drops of water are applied dynamically.

FIG. 3 shows an enlarged plan view of part of the outer surface 16 of the fluid roller 10 according to the invention.

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The random distribution of the gaps 18 and their essentially uniform width can be seen with the formation of islands 20 of approximately the same size. The term "random pattern" is understood here to mean interconnected gaps which form the disconnected and inhomogeneous surface shown and described. The arrangement of the columns is random or irregular due to their manufacturing process. However, they form islands 20, the size and number of which, as well as the gap size and number, are carefully controlled. This is an essential feature of the invention. A further essential feature of the invention lies in the density of the column 18 opposite the smooth islands 20. The gap density or occupation rules is in the embodiment of Figure 3 14 to 17%, wherein the dynamic for the Operation for the transfer of relatively non-viscous fluids such as water an occupancy of about 15 % has proven advantageous. Gap depths of 0.025 to 0.05 mm and approximately the same width have also proven to be advantageous in order to achieve optimal results.

FIG. 4 shows another gap coverage in the order of 20 %. It is clear that the figure indicates an average value for the column opposite the islands 20. The size of the column 18 is preferably not affected. It has been shown, however, that with increasing

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the gap density in the islands 20 shallow gap depressions arise. If this happens then it will result in a Avoidance of the gap pattern 14 according to the invention and leads to a roller surface provided with depressions, which is more similar to the prior art and does not have the fluid transfer properties of the invention. Those belonging to the state of the art, with indentations provided roller surfaces do not cause any lateral distribution of the fluid, as the gaps are not connected to one another. In dynamic operation, the gap pattern 14 according to the invention, the fluid transfer under pressure from a fluid supply device, for example pressed rollers, relieved. In the following, that stress is referred to as "pressed in under pressure" understood by rollers in which the profile of one or both is pressed into the other. The split pattern 14 in the same way facilitates the application of the fluid to the desired substrate, since the latter in the Gap pattern 14 flows.

FIG. 5 shows an enlarged, schematic illustration of the fluid roller 10 in operation. Fluid is made with the help of a second roller 22 is applied to the fluid roller 10. However, the application of fluid can also be applied to any other Way. In one embodiment, the fluid wrrd transferred to the fluid roller 10 under pressure, including in a

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other design other pressure devices are provided. The second roller 22 has a soft outer surface 24 and is at the transition point 26 from the hard fluid roll 10 pressed in. A fluid gap 28 with fluid 30 is created at the transition between the two rollers. The fluid 30 becomes pressed through the transition point 26 and transferred to the fluid roller 10. This is where the prior art occurs Difficulties that are avoided according to the invention. The thickness of the fluid layer formed in this way 32 on the fluid roller 10 according to the invention is more uniform and larger than in the known hard ones Rollers. With the known rollers, it is true that large layer thicknesses can also be transferred, for example with the "Anilox" roller, but the quality of the transfer is lower than that of polished hydrophilic rollers. Apart from that on the fragility of copper-clad rolls, especially when a certain critical value is exceeded Speed value, the driving forces on rollers that are driven at different speeds cause difficulties, which can cause residues to accumulate in crevices or depressions.

The manufacture of the fluid roller 10 includes various coating and etching processes, with suitable processes for example relate to the manufacture of an inverted shape as the fluid roller 10: namely, the manufacture

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of engine cylinder liners. The gaps formed in the process are worked into the inner wall of the cylinder liner;
they are generally very deep to hold oil for lubrication purposes. Various methods of chrome and iron coating with different gap patterns are known for this purpose. The gap pattern formation for cylinder liners creates pockets for the storage of oil and the reduction of friction and wear. These locations, often referred to as "pores", are electrically etched into the hard metal surface. The islands 20 remaining between the pores are honed or polished to give a proper sliding surface. Various electroplating etching processes are known for creating the desired porosity properties in the smooth surface. So far, however, only cylinder liners have been machined in this way, but no reference to the application of these methods to the production of fluid rollers can be found in the prior art.

The gap pattern 14 according to the invention for the fluid roller 10 provides a synergistic effect. The flow properties correspond neither to the smooth nor to the rough rolls belonging to the state of the art. A modification of the gap density, gap dimension and those described herein Gap arrangement provides only a few advantages without the same

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also have critical disadvantages at an early stage.

The production of the gap pattern 14 can be accomplished, for example, in the following way:

First, a cylindrical core is prepared for coating with chrome or a similar coating. Of the The core is aligned very precisely with respect to the coating anode in order to produce a uniform coating. When the applied metal reaches a given layer thickness of the order of 0.5 mm it is electro-etched, the polarity of the current being reversed and parts of the applied metal being removed will. The interconnected gaps 18 extend into the outer surface to a depth of about 0.25 mm 16, depending on the layer thickness. Then the etched roller is honed or on a lathe or a similar device to reduce the plating thickness, polishes the surface dimensions and layout set within precise limits and the smooth, uniform islands 20 with intervening gaps according to Figures 1 to 4 to be obtained. The etching and polishing must be carried out to form the gap pattern of the present invention 14 must be coordinated with one another. A gap depth between 0.025 and 0.075 mm has proven to be sufficient. For this purpose, the initial layer thickness of the

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cylindrical core deposited metal often larger than with conventional plating processes, while the etching in takes place in a controlled manner and the polishing is precisely coordinated with the etching.

For operation, the fluid roller 10 is first treated with a suitable agent, for example for chrome surfaces with hydrochloric acid to make all surfaces, islands 20 and gaps 18 capable of absorbing fluid. Then will the fluid roller 10 is mounted on a fluid supply device and an application area. According to Figure 1 presses Fluid roller 10 against a soft roller, both rollers being drivable either independently of one another or together are. A certain turbulence is transmitted to the fluid layer by the rotating transition points 26. This turbulence is due in part to a cross-flow of fluid in the gaps 18, which is a smooth Roll surfaces significantly disrupts laminar flow. For example, fluid rings or humps are formed laminar fluid flow on smooth, contiguous, hydrophilic surfaces. Due to the dynamic surface effect the gap pattern 14 according to the invention prevents such ring formation. This is especially for lithographic humidification systems are advantageous, in which alcohol is often in the wetting fluid or in the spray solution is used to reduce surface tension.

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The inventive gap pattern 14 makes the use of alcohol and similar wetting agents superfluous, so that more economical fluid transfer is possible.

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Claims (30)

UEXKÜl.L & STOLBCRG pf-ofl '..- sional klpreocntatives PATfNiAtMWALTc Bl. Ί ORE TmE FUROPEAN PATENT OFFICE BESELERSTRASSE 4 D 2000 HAMBURG 52 DR J D FRHR from UEXKULL OR ULRICH GRAF STOLBERG DIPL ING JÜRGEN SUCHANTKE DIPL ING ARNULF HUBER DR ALLARD from KAMEKE DR KARL HEINZ SCHULMEYER Epic Products (priority: February 26, 1979 International Corporation _{us Q15 331} _ _164y8) Regal Row, Suite 215 Dallas, Texas 75247 / V.St.A. Hamburg, February 1980 Fluid roller Expectations Vl /. Method for producing a fluid roller with hard ter surface for the transfer of fluid in connection with other rollers of a fluid transfer system, marked by: - Providing a cylindrical core which is rotatably mountable in a fluid transmission device; - Application of a hard metal coating on the outer surface of the cylindrical core; - Etching of the coated core to form a random pattern of interconnected columns and intervening, discrete islands in the metal-coated outer surface; 030036/0592 - Polishing the outer surface of the fluid roller to form smooth, finely machined islands between the interconnected gaps that take up to 30% of the surface area of the fluid roll .; and Cleaning of the outer surface and the gaps of the fluid roller in order to make the fluid roller surface ready to receive fluid close. 2. The method according to claim 1, characterized in that the metal coating is carried out with chromium. 3. The method according to claim 2, characterized in that the core in the etching of the coated core Hydrochloric acid is immersed. 4. The method according to claim 1, characterized in that the metal coating with a thickness up to 0.5 mm is applied. 5. The method according to claim 1, characterized in that the gaps occupy between 9 and 26% of the surface of the fluid roller. 6. A method for producing a metallic fluid roller from a cylindrical core, characterized by: 030036/0592 Applying a metal coating to the outer surface of the cylindrical core; Etch the coated core to form a random pattern of crevices and islands in the metal coated Outer surface, with the gaps occupying up to 30% of the surface of the fluid roller ;, and Polishing the islands between the crevices to achieve a smooth, finely machined surface, in which the gaps have a depth of up to 0.075 mm. 7. The method according to claim 6, characterized in that the metal coating is carried out with chromium. 8. The method according to claim 7, characterized in that the etching of the coated core by immersion of the core takes place in hydrochloric acid. 9. The method according to claim 6, characterized in that the metal coating in a thickness up to 0.5 ram is applied. 10. The method according to claim 6, characterized in that the gaps occupy between 9 and 26% of the surface of the fluid roller. 030036 / 0592- 11. The method according to claim 6, characterized in that the roller for transferring fluid to others Rollers is pressed and pressed into this. 12. A method of transferring fluid between a hard and a soft roller in a fluid transfer device, marked by: Providing a cylindrical core in the fluid transfer device is rotatable mountable; Etching of the coated core to form a random distribution of crevices and islands in the metal-coated Surface; Polishing the surface of the roller to form smooth, finely machined islands between the gaps, which occupy up to 30% of the surface of the roller; Clean the surface of the roller to get it on the polished surfaces of the islands and in those in between to make lying gaps fluid absorbent; Mount the roller with pressure on a soft roller to rotate the hard roller and the gap pattern opposite the soft roller; Driving the hard and soft rollers in contact with a fluid to be transferred; and 030036/0592 Passing the fluid between the hard and the soft roller. 13. The method according to claim 12, characterized in that during the passage of the fluid between of the hard and soft rolls, the fluid interacts with the rotating gap pattern of the hard roll and thereby generating turbulence in the fluid passed therethrough. 14. The method according to claim 12, characterized in that the surface tension during the passage of the fluid between the hard and the soft roller
of the fluid passed through to facilitate the
Fluid transfer is broken up mechanically. 15. The method according to claim 12, characterized in that the coated core for etching in hydrochloric acid is dived. 16. The method according to claim 12, characterized in that the application of the metal coating in one Layer thickness up to 0.5 mm takes place. 17. The method according to claim 12, characterized in that the gaps occupy between 9 and 26% of the surface of the roller. 0300 3 6/0592 18. The method according to claim 12, characterized in that the metal coating is carried out with chromium. 19. Fluid roller for the transfer of fluid, with a hard outer surface in the form of a coating on a cylindrical core, which is rotatable in contact with a fluid supply device and a fluid application surface, characterized in that the outer surface (16) of the fluid roller (10) with a irregular, relatively flat gap pattern (14) consisting of interconnected gaps (18) and polished islands (20) in between, the gaps (18 ) occupying up to 30% of the surface of the fluid roller (10) in order to avoid an uneven, to form inhomogeneous fluid acquisition surface. 20. Fluid roller according to claim 19, characterized in that the coated metallic outer surface (16) is made of chrome. 21. Fluid roller according to claim 20, characterized in that a random gap pattern (14) in the chrome layer is etched and polished. 22. Fluid roller according to claim 21, characterized in that the applied to the cylindrical core 030036/0592 Chromium layer initially has a thickness of up to 0.5 mm and that the mean polished cleavage pattern depth is up to 0.075 mm. 23. Fluid roller according to claim 19, characterized in that the gaps (18 ) occupy between 9 and 26% of the surface of the fluid roller (10). 24. Fluid roller according to claim 19, characterized in that the gaps (18 ) occupy between 14 and 17% of the surface of the fluid roller (10). 25. Fluid roller according to claim 19, characterized in that the fluid supply device is a soft roller (22) which rotates with the fluid roller (10). 26. Fluid roller according to claim 19, characterized in that the fluid application surface is a soft roller, which rotates with the fluid roller (10). 27. The fluid roller according to claim 19, characterized in that the fluid application surface is one over the fluid roller (10) is a movable web of material for receiving the transferred fluid. 28. Fluid roller according to claim 19, characterized in that the gap (18) initially has a medium depth 030036/0592 of 0.25 mm in the outer surface (16) of the fluid roller (10) and that after polishing its middle Depth in the outer surface (16) is 0.05 mm. 29. Fluid roller according to claim 28, characterized in that the gaps (18) after the polishing of the fluid roller (10) have an average depth lying between 0.025 and 0.05 mm in the outer surface (16). 30. Fluid roller according to claim 19, characterized in that that the gap (18) in the outer surface (16) of the fluid roller (10) is between 0.025 and 0.05 mm have medium width. 030036/0592