DE3225982A1 - INK FOR A LITHOGRAPHIC PRINTING MACHINE - Google Patents

Description

Dahlgren Manufacturing Company, '3305 Manor Way, Dallas, Texas 75235, V.St.A.

Inking unit for a lithographic printing machine

The invention relates in particular to an inking unit for a lithographic printing machine, with a by means of a drive drivable application roller with elastic surface, which under pressure on a Pressure plate rests, a strip-shaped ink metering element, and a support means for supporting the dosing member designed in the manner of a cantilever arm, whose non-supported end is pressed into the elastic surface of the application roller, with the rotation of the applicator roller from this an excess of paint to the non-supported end of the cantilever arm is moved.

Inking units for printing plates on the market entrance 512/18

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found generally contain two to four forming rollers which are in rolling engagement with a printing plate stand. Each of the forming rollers is normally in rolling engagement with one or more oscillating rollers, on what color by a large number of rollers in a roller train of rollers with different Diameters is supplied, the compactors generally arranged or constructed in the manner of a pyramid are. Color is supplied to this roller train via a ductor roller, which engages and disengages through Is to bring oscillatory movement and has an uneven color film. The uneven film will formed by a flexible doctor blade that engages a hard surface on a slowly rotating ink fountain roller is pressed by many ink keys.

The ink film formed on the ink fountain roller is too thick and too uneven to be placed directly on a printing plate to be applied with a quality print. These inking units, which include a large number of rollers, are provided to reduce the thickness of the paint and to keep a film of uniformly controllable thickness to deliver on the printing plates. However, there is the "starved" ink film on every form roller during printing is not completely refreshed with each rotation of the forming roller, so-called ghost images are known to occur or color accumulation on the one hand and color deficiency on the other.

In trying, both the cost and the cons to prevent such multi-roller inking units, Efforts have been made to inking units

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to develop, in which a new, fresh paint film is dosed on an elastic forming roller, which is in relative pressure engagement with a planograph printing plate was made to eliminate the roller trains, eliminate the ghosting, and last but not least, the excessive accumulation or "starvation" of color.

In a known system there are two rollers of approximately the same diameter, which are below mutual pressure abut against each other and form a gap, wherein the adjacent surface sections move in the opposite direction at the gap. One of the rollers is completely cleaned by a pair of doctor blades, and the rollers are brought together under pressure so that the local Pressure at any point along the contact line or the gap is greater than a "critical pressure threshold value" so that theoretically one of the rollers carries a film of paint of constant thickness over the length of the rollers, which can be applied directly to a printing plate without first coming into contact with leveling rollers to come or to have to come. However, since the adjacent surfaces of the rollers on the Gap move in the opposite direction, and there is pressure across the length of the gap between the rollers is not uniform, has the temperature that is on the adjacent surfaces, which are in move in the opposite direction, is generated, with the result that a substantial temperature change is over the length of the rollers is made and accordingly the color carried by the rollers. Furthermore considerable power is required to turn the rollers and to adjust the film thickness of the dosed dye

films at the gap is not very sensitive because there are already slight changes in the surface speed the roller that has been completely cleaned of paint, downright drastic change that of the ink film thickness worn on another roller.

Ideally, a stationary metering unit should be used for those known from the previously known inking units Problems may be a solution that does not require a drive in addition to that for rotating a single forming roller is required. Attempts have been made in which doctor blades (doctor blades) are provided as metering units, but these attempts have proven to be unsuccessful exposed. Doctor blades are has been used successfully as ink stripping devices in inking units that use a roller train for distributing and smoothing the color, but such blades have not been found to be suitable for solely as ink metering units for a forming roller with an elastic surface in a lithographic one Pressure application to be used.

Generally speaking, printing ink is an oily, viscous substance that is highly enriched with pigment and which can be described as sticky, so that the color as intended on the image sections of a lithographic printing plate adhered. If the image portion of the printing plate paint directly on paper or A cloth cylinder transfers, which in turn transfers the color to paper, small fibers, lint or stick Fragments of coating material] or the like. on the surface of the plate cylinder. The plate causes

this foreign material gets on the surface of the inking roller. When the surface of the inking roller is moved directly into the ink supply and then with a conventional doctor blade (doctor blade) is scraped off for the purpose of cleaning, such foreign particles tend to stick to the edge the metering blade, causing the formation of an uneven paint film on the roller surface has the consequence. For this reason, in addition to the random behavior of the surface, the elastic No inking device has yet been developed or proposed for roller under dynamic conditions which is suitable with a doctor blade for the purpose of continuous metering (dosing) of a uniform film directly onto the surface of a resilient roller in rolling engagement with a pressure plate to effect.

Between a fixed edge and the surface of an elastic roller can be dynamic Conditions no uniform pressure can be maintained, since the respective modulus of elasticity of the elastic The surface of the roller increases as the periodic load increases. The dimensions of the elastic forming roller change under dynamic conditions when the elastic surface is exposed to periodic load changes is because elastic material has a so-called "memory" and does not change immediately recovered that the original original dimensions are restored after such an elastic Surface has been subjected to compression. Furthermore, vibration and fatigue of the elastic roll surface through a substantial

Indentation of the surface induced or generated, since the elastic jacket is "dammed" as it were Result of the compressive loading on one side of the stationary, solid edge, and since it is on the other Side of the edge is under tension. A vibration of the axis of the roller relative to a stationary, fixed one Edge resulting from movement of the roller surface into and out of the nip in the plate cylinder is not to be completely isolated from the solid supporting edge.

The present invention addresses the problem of forming a continuous film of printing ink same thickness on an elastic roller surface to and the problem directly related to it, the color film in engagement with the image portion on a to move lithographic printing plate, with the above-mentioned roller trains, which are known at Inking units are available, should be avoided, while continuing to require excessive power Dosing a thin, even paint film should be avoided, and the problems should be solved, which deals with an accumulation of lint or the like. result. Furthermore, a dosing member is to be created, which an elastic roller surface is not insubordinate Way claimed and accordingly can damage, with the roller surface as possible no or at most a harmless vibration should be transmitted, and finally one should be transmitted overall Dosing device are created with which it is possible to form a uniform film, the Thickness independent or at least practically or largely independent of the printing press speed

The subject of the application deals with improvements to an inking unit, as described in the US patent application the file number 142 596 of April 22, 1980 has been disclosed, this disclosure herewith at the same time is made to disclose the present patent application.

Such an improved inking unit, as it is the subject of the present patent application, comprises a single one Application roller with an elastic surface that determines is suitable and accordingly capable of relative pressure engagement with a lithographic printing plate to work together, in combination with an improved ink metering member, which is suitable for a thin, to form a controllable and uniform film of printing ink on the surface of a forming roller, its ink film thickness regardless of the surface speed of the elastic roller.

The surface of the roller, which moves out of the engagement area with the pressure plate, is through a Reservoir, i.e. a supply of paint, moved so that an excess of paint on the surface of the Roller is applied or that such arises there, around the "exhausted" sections of the ink film to refresh after printing on the plate. A metering member with a metering surface for a certain paint viscosity is in relation to the elastic Surface of the roller brought to form a wedge-shaped intake section to which the excess ink transported through the roller surface

is used to form a thin, uniform film of ink that adheres to the elastic surface of the Roller is sticking.

The thin, flat or even, right-angled body of the metering member is approximately tangential to the Roller surface placed in position so that the paint strikes like a weir against the thin side or edge of the metering member. If the Positioning is done so that the angle between the metering member and a tangent is smaller than 30 °, the metering member is fixedly supported in the tangential direction and flexibly supported in the radial direction. A trapezoidally shaped metering member or a metering section of such a metering member is attached to the thin edge of the metering member formed in order to achieve an optimal diometric relation for the purpose of metering To form paint, and to separate the metered or metered paint film from the metering member, while the Dosing member is held or supported essentially tangentially to the elastic roller surface.

The metering member is mounted so that two polished, flexible edges of the trapezoidally shaped metering section are separated by a support surface and are radially relative to the axis of the elastically coated Move the roller. The edges are towards the elastic surface of the roller moved under pressure or bias to a substantially constant metering relation relative to the Roll surfaces along the scimped length of the roll and to form or generate in the circumferential direction. the polished, flexible edges of the metering member

accordingly firmly supported in a substantially tangential direction with respect to the roll surface, and the trailing edge is oriented in such a way that it deforms the resilient roll surface in order to dampen a substantial part To minimize surface portion of the metering member downstream of the polished trailing edge and effecting separation of the paint from the metering member adjacent the polished trailing edge. Accordingly, the rear surface of the trapezoidally shaped metering section is the metering member Shaped or designed so that color on the indented, elastic roller surface does not separate from the roller surface and collects or collects on the rear surface of the metering member. builds up when this regresses from a compressed situation that results from the relevant surface section passes the flexible, polished rear edge of the metering member or has happened.

Accordingly, a primary object of the present invention is in consideration of the aspects related to the object already referring above statements therein, an inking unit or a color system for To create printing machines with which a continuously precise control of the ink film thickness is possible, which is supplied on a lithographic printing plate in order to thereby in particular the formation of so-called. Avoid ghosting and a change in color or color density in the printed images ultimately result in a considerable waste of time and material and corresponding costs. A further rounding off of the task for the registration subject is for the competent specialist

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based on the description above and below, taking into account the other documents recognizable.

Preferred embodiments of the present invention are described in the subclaims.

The invention is based on exemplary embodiments below further explained with reference to a drawing. It shows:

1 shows a cross section through a lithographic printing machine;

2 shows an enlarged partial section in a cross-sectional view, which the relation of the metering member relative to an elastic coated forming roller shows in static state and under dynamic operating conditions;

3 shows an enlarged, partial cross section of the trapezoidally shaped metering section at the working end of the dosing member;

4 shows the mutual relation of different surfaces of the metering member to one another;

Fig. 5 is a graph showing in principle that if a force the metering member in relative pressure engagement or indentation with a

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Roller surface brings, and if this Force is increased, a minimum ink film thickness is reached at a certain angular relation between the metering member and the roll surface;

6 shows a curve representation similar to FIG. 5, which shows a family of curves for various Shows the angle of the metering surface relative to a radial line to the roller;

7 is a graph showing the change in color density in the transverse direction over a printed sheet as a function of a change in the force with which the edge of a Dosing member in relative pressure engagement with an elastic roller surface is brought or pressed;

8 is a graph showing the change in positioning of a Edge of the metering member shows when a resilient coated roller is rotating at a constant speed and also at changing speeds;

Fig. 9 is a graph showing that the ink film thickness is independent of the Press speed is; and

10 shows a somewhat schematized or combined

fold-out chart showing the density of colors on a printed sheet.

Identical and identically acting parts are in the individual illustrations or figures provided with the same reference numerals.

The inking unit, generally designated 1 in FIGS. 1 and 2 of the drawing, is spaced apart from one another arranged side frames 2, which are attached to side frames 3 of a printing machine, which a conventional Plate cylinder P, a blanket cylinder B and an impression cylinder I for printing on a web W or on sheet material, in particular on paper.

A support device 5 is provided in order to adjustably fasten a metering member 10 between the side frames 2 and to position the metering member 10 relative to an application roller 40 provided with an elastic coating. The opposite ends of the application roller 40 are rotatably mounted on the side frame 2 in suitable bearings. The applicator roller 40 is driven by any suitable drive means such as a chain 4 which drivingly connects a sprocket on the plate cylinder to a sprocket on a coupling (not shown) at one end of the applicator roller 40. The surface speed of the form roller 40 is preferably substantially equal to the surface speed of the plate cylinder P.

Side limits 6 are attached to the support device and are in sealing engagement with one another opposite ends of the applicator roller 40 pressed, and the metering member 10 forms an ink reservoir or an ink supply R, from which the ink is dosed onto the surface of the applicator roller 40. One or more Ink supply oscillating rollers 8a and 8b are rolling with the ink on the surface of the applicator roller 40 Intervention to remove any irregularities on the upper

to smooth surfaces that may occur in the paint film before the paint film from the surface of the Application roller 40 to the dampening unit D and to the surface of a printing plate P 'of the plate cylinder P. will be carried. The ink supply oscillating rollers 8a and 8b are in rolling engagement with the ink the surface of the applicator roller 40 and not only smooth surface irregularities or resemble them but also change a smoothed finish of the dosed color film into a smooth one matte finish to condition the paint film for proper moistening and for application an image portion of a printing plate.

It can be seen that when the surface of the applicator roller 4O moves away from the surface of the printing plate P ¹ , the surface is again smoothed and conditioned by an inking and dampening liquid supply oscillating roller 8c before it is immersed in paint and an excess of paint in the Ink supply R is applied to it.

If the ink system is used for lithographic printing, dampening liquid is first applied to the ink on the surface of the application roller 40 and then onto the printing plate P ¹ on the plate cylinder P. Means are provided with which dampening liquid is evaporated from the surface of the application roller 40 or the like. is to prevent an accumulation of superfluous dampening liquid in the ink supply R. As shown in Fig. 1 of the drawing, a hollow, perforated or slotted tube 9 extends transversely between the side frames 2 and is apertured

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provided, through which dried compressed air is passed to a stream of dry air to straighten the surface of the applicator roller 40. At least one end of the tube 9 is over a Hose line or the like. connected to a suitable air source, not shown.

When dampening liquid in the inking unit according to the invention is used can also have a greater than normal ratio of alcohol to Water should be provided to print with less water, and to prevent evaporation or evaporation to accelerate the dampening liquid, which on the applicator roller 40 remains when it moves away from the printing plate P '. So could the dampening liquid solution Contain more than the normal 5 to 25% alcohol to ensure rapid evacuation of the Ensure dampening solution from the applicator roller, when this moves between the plate and the paint metering member. The alcohol, one or more Rollers 8c and the air, all of these measures can do their part to reduce excess dampening liquid remove after printing and ensure a new distribution.

As will be explained in detail further below, are to create a precise control of the viscosity of the paint contained in the paint supply R and, if this is desired, to change the paint viscosity with the paint supply R flexible tubes 7 or the like. connected to give a liquid such as water at a controlled temperature and to a controlled extent into one end of a conduit 5 'of the support means 5 and from the other end of the conduit 5 ¹ again

lead out.

For high speed printing, the physical properties of the color film 130, which is between the metering member 10 and the elastic jacket or coating 44 of the roller 40 is formed and the im Color supply R existing color continues to be controlled by temperature a liquid are controlled, which by the oscillating rollers 8a, 8b or 8c and / or a Line in the core 42 of the roller 40 flows. It has been found that a large flow rate only one generated small temperature changes along the length of a roller, and that by monitoring and controlling the Outlet temperature heat dissipates and the color temperature can be controlled so that the physical properties of the film produced is kept essentially constant over the length of a production process can be.

Accordingly, by cooling or heating of the liquid by the support device 5 and / or the Roller core 42 and / or the oscillating rollers 8a, 8b or 8c flows, the ink viscosity on and before the next Gap N still defined below is controlled in order to achieve a constant desired color film for the purpose of proper Keep pressing down on the plate P '.

The dosing member

A preferred embodiment of the color metering member is shown in FIGS.

In particular from Fig. 4 it can be seen that the color metering member 1O a smooth, polished, finely machined precision

Has metering edge 25, which at the connection point or penetration of a metering surface 24 and a support surface 26 is formed.

The metering edge 25 preferably extends in length over a distance within a range of 10 to 80 inches (about 25 to 200 cm) depending on the width of the printing machine, and is formed by the penetration of the polished surfaces 24 and 26. The polished surfaces 24 and 26 meet at an obtuse angle, that is to say form a type of wedge with an included angle A ₁ which is approximately 120 or greater.

The metering edge 25 is preferably made of a relatively hard metallic material with a Rockwell hardness from C 48 to 50 or more. It is important that the polished metering edge 25, the metering surface 24, the support surface 26, the rear edge 28b of the support surface 26 and the adjoining, hereinafter also referred to as "Third surface" designated rear surface 28a of the metering member are wear-resistant, since they are in the resilient surface 45 of the forming roller 40 are depressed during normal operating conditions.

The metering member 10 is preferably elastic, i.e. it consists of flexible, metallic material with a Young's modulus of about 30 10 psi or less to provide the property that one is looking for the metering edge 25 when rotating the forming roller 40 with regard to the comparable sequence of movements as a "pickup effect" (compared to a record player).

A metering member 10 is made from a strip of stainless spring steel which has been sheared off with good results Edges have been manufactured, which are on the market for example by the company Sandvik Steel, Inc., Benton Harbor, Michigan / USA, and under the name Sandvik 7 C 27 Mon 2 is distributed.

The strip of stainless steel was especially popular because of its hardness, flatness, elasticity, grain structure and its smooth surface finish, to ensure high wear resistance and good fatigue properties. The stripe The stainless steel was 0.070 inches (approximately 1.78 mm) thick and approximately 5.3 inches (approximately 5.3 inches) wide. 135 mm). The strip of material was heat treated and had a shiny polished surface finish, one extra precise thickness and normal strength. The width tolerance was -0.016 inches (about 0.4 mm) and the thickness tolerance was -0.00181 inch (about 0.046 mm). The stainless steel strip was corrosion resistant in the presence of air, water and most of the organic acids in dissolved form at room temperature. The tensile strength was about 249,000 psi corresponding to a Rockwell hardness of C 49.

Originally, the edge at the junction of surfaces 22 and 26 had serrated notches, which a correspondingly serrated Edge contour resulted. To form a straight, precision edge and a continuous line across the extent of the metering member 10, the surfaces 24 and 26 were ground at a predetermined obtuse angle and then ground with a fine grain stone,

as will be explained in more detail below, as the first step in the formation of the polished metering edge 25. The strip was then clamped in a special holder. The area 24 of the strip was Apply a super finish by hand at a specified angle using a fine-grain whetstone and then polished by hand with 600 grit sandpaper.

As a final step, the stainless steel strip was placed on a flat horizontal surface arranged. The surface 26 was then given a super finish by hand, namely with a Fine-grain grindstone and then hand-polished with 600 grit sandpaper.

If on the metering member during superfinishing and Polishing the surfaces 24 and 26 results in a sharpened edge, this should be done with leather or a polishing agent removed. If these are sharpened "springy" or provided with wire-shaped irregularities Edge has been removed is a smooth, continuous, uniform, defect-free edge on the strip educated. Accordingly, in polishing or "sharpening" the obtuse angled edge 25, the "sharpness" of the edge can be increased may be altered slightly to form a non-cutting edge that does not pierce the film. This manufacturing process creates a fine, continuous, smooth, straight, polished, sophisticated, uniform, super-finished edge 25 with minimal surface irregularities. There should be no small nicks or protrusions in the edge. The ones from the edge 25 formed by polished surfaces 24 and 26 is a

extremely fine edge that has been polished to create the highest quality super finish and to realize the texture as perfectly as humanly possible. Surfaces 24 and 26 are preferred Finished so that RMS 4 is not exceeded. The designation used above and below "Super-Finish" refers to a surface that is sanded and polished so that the surface peaks are removed and flat, even surfaces are formed, which, however, still have the smallest "valleys" or have reservoirs to accept and carry the lubricant color.

The edge 25 is finished to a surface finish which approximately corresponds to that of the edge of a razor blade. It can be seen, however, that the obtuse angle A ₁ between surfaces 24 and 26 is significantly greater than the corresponding angle of a razor blade and that accordingly an obtuse, obtuse, non-cutting and non-penetrating edge is formed. In fact, the surface 24 merges into the surface 26 via the edge 25, as it were, with a continuous, polished surface being formed or being present on each side adjacent to the metering edge 25.

The material used to form the edge 25 not only has to be hard enough and able to produce a blunt, to create or make available fine, polished, uninterrupted edge, but the material must also be tight and yet flexible over the length of the metering edge 25. The edge 25 should be lengthways be quite flexible, so that the edge 25 when pressed under pressure into the elastic surface of the

Is applicator roller 40 comparable accordingly or bent under the influence of the surface of the roller 40 _r yields so that the edge 25 and the surface of the roller 40 can adapt to each other, and thus a substantially uniform depressed portion over the length of the roller 40 is formed will. As will be discussed in greater detail below, the resilient jacket 44 of the roller 40 is on the order of 3/8 to 5/8 inch (about 9.5 to 15.9 mm), preferably about 1/2 inch, in thickness (approx. 12.7 mm), and an elasticity of approx. 40 to 70 Shore A hardness, preferably 60 Shore A hardness units. This "bias" of the edge 25 in order to achieve a corresponding adaptation to the surface of the roller 40 should be possible without excessively depressing the surface of the roller when it is under dynamic running conditions.

The edge 25 of the metering member 10 should be arranged so that it is resilient towards the surface the application roller 40 is pressed, and that it over its entire length in the radial direction to the application roller 40 is freely movable. The edge 25 must also be in a substantially tangential direction to the applicator roll surface be firmly supported.

An ideal support for the metering edge 25 is a flexible lever arm (= cantilever arm) that carries the edge 25 and on the one hand for the required flexibility and on the other hand for the required strength or firmness Provides support. Although the edge 25 is, for example, part of a separate essentially in cross-section can be trapezoidal element which is functionally connected to the lever arm, there is a preferred Design in which the edge 25 of the trapezoid

to form shaped section 10 on the arm itself, so that both are an integral unit. In order to achieve this, the lever must be split in two Directions be flexible, namely along the length of the edge 25 and also along the width of the Strip, i.e. the length of the arm.

The color metering member shown in Fig. 4 of the drawing, in which the edge 25 is formed on the unsupported end portion 10 'of the lever or cantilever arm is, has a substantially rectangular cross-section defined by front and rear side surfaces 22 or 22 ', an upper side 28 and a lower side 29 is formed. The support surface 26 lies essentially in the plane of the underside 29 when the lever or Cantilever is not bent. The dosing area

24 and the support surface 26 penetrate one another to form an obtuse angle A ₁ and intersect at an apex 25, which is essentially a straight line.

The lever or cantilever arm, which is the obtuse-angled edge

25 has, for example, from a thin, flexible, elongated strip of stainless steel or a corresponding strip-shaped material exist or be manufactured, as already described above and may have a thickness of, for example, 0.070 inches (about 1.78 mm) and a width of 5.3 inches (e.g.

135 mm) or less. The width of the lever or the length of the material strip is preferably approximately within the range between 2 5 cm and approximately 2 m the lever is flexibly supported over the length of the edge 2 5, as well as this over the length of the

Lever arm is the case. The modulus of elasticity of the lever arm can be 29 χ 10 psi, for example and is known to be a measure of the stiffness of the material, i.e. its resistance to deformation When this value is combined with the moment of inertia I, the EI factor gives the rigidity of the lever arm.

The special or specific dimensions and characteristics of the metering member 10 are exemplary has been shown or named, and it should be noted that these dimensions, characteristics and Installation conditions can of course be changed for special conditions. Accordingly are preferred dimensioning ranges have been specified here.

The metering member 10 also has a recess in the underside 2 9 of the strip of material from which the Dosing member 10 is formed.

The portion of the strip of material used to form a polished edge 25 to be polished is covered and the metallic material is adjacent to it through mechanical or chemical grinding removed in order to remove part of the metal in this way, without creating stresses that can deform the strip.

The third surface 28 a, which is adjacent to the support surface 26, is smoothed by a sanding finish in order in this way remove about 0.003 inch (about 0.076 mm) of rough surface material. The third surface 28a can then with 600-

(grit) sandpaper can be sanded to a very smooth surface finish on surface 28a to form or manufacture. The rear edge 28b is accordingly designed as this further has been set forth above with reference to the edge 25.

If the thickness, i.e., the distance between surfaces 26 and 28, of the strip of material is 0.070 inches (about 1.78 mm) is, the depth of the recess 27 is preferably greater than 0.020 inch (about 0.5 mm), for example 0.035 inch (about 0.89 mm), so that the material thickness between the surface 28 'forming the top of the recess 27 and the top 28 approximately 0.035 inches (about 0.89 mm) amounts to.

The third surface 28a intersects the polished support surface 26 at an angle A ¹ in a range between 30 and 90 ° (the latter as shown). The upper portion of the metering surface 24 of the metering member 10 can extend to the top 28 or be angled at an angle to form the front side surface 22 (as shown).

The metering surface 24 can accordingly only be a relatively small chamfer of the original one act front side surface 22. The obtuse angle A not only creates a metering element with an obtuse, obtuse angled edge that is not "fragile" but is mostly at a certain angle or shaped in a specific design in order to allow the metering of a specific color film thickness for a specific color To enable viscosity and color intensity, and around the

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Dosing the film without an immediate change in the direction of the roller surface and without too much Indentation of the roll shell, which causes rapid wear of the metering member and / or the roll shell would result.

In the embodiment shown in the drawing of the metering member 10, the polished metering surface 24 extends from the polished edge 25 over a Distance upwards, which is approximately equal to the depth of the recess 27 or greater and the surface 22 intersects or penetrates. It can be readily seen that the polished support surface 26 supports the polished edges 25 and 28b. When surfaces 24 and 28a are parallel, surface 26 can be refinished without the stress characteristics the polished edge 25 of the metering member 10 to change.

The surfaces 26, 24 and 28a and accordingly also the edges 25 and 28b can be easily renewed. By a slight re-finishing of the support surface 26 can both edges be "sharpened" again at the same time or surfaces 24 and 26 can also be resharpened. After considerable use a small radius or curvature can arise at the edge 25 and change the metering properties. In order to avoid replacing the entire metering element, the regrinding described above can be carried out and hand finishing can be repeated several times before replacing the entire metering member got to. Typically 1/1000 to 3 / 10OO of an inch removed from each surface to be machined, the extent of after machining on the extent of wear

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depends in order to relocate or "sharpen" the edges 25 and 28a again.

For finishing the surfaces 24 and 26, a special holder can be used to prevent damage to prevent the metering member. Such a holder should not only hold the metering member, but also guide surfaces for the fine grinding treatment with a honing stone or the treatments with Create sandpaper to ensure that only a minimal amount of material is removed, and that the angle A. and the edges 25 and 28 are maintained will.

The angle A 'should be large enough to prevent any ink film from being present on the surface of the roller 40 to allow to separate from the support surface 26 without both of the support surface 26 as well as paint accumulates on the third surface 28a, with the result that paint that has accumulated there then drips off and causes non-uniform pressure.

The applicator roller

The applicator roller 40 has a hollow, solid, tubular metal core 42 and an elastic, non-absorbent one Jacket 44, which is attached to the core 42, the jacket 44 a uniform has a smooth, evenly textured and elastically resilient outside or surface 4 5. Of the The coating or jacket 44 of the applicator roller 40 is elastic but relatively firm, for example in one

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Range between 40 and 70 Shore A.

The jacket 4 4 of the application roller 40 is preferably made made of an elastic urethane, polyurethane, rubber or a rubber-like or rubber-like material, which is attached to the metallic core 42. In a preferred embodiment, there is Jacket 4 4 made of Buna nitrile rubber, which creates a natural surface with microscopic pores ensures that color is absorbed and retained in it and that a thin color film can be dispensed, which is suitable for lithographic printing applications.

The jacket 44 of the applicator roller 40 should have high strength, high tear and abrasion resistance and be resistant to oil, solutions and chemicals. The coat 44 should also have a relatively low indentation resistance, good recovery capacity and have uniform ink absorption properties. A suitable jacket can, for example, be made of urethane or rubber in order to produce an elastic coating of preferably about 60 Shore Α hardness.

A suitable urethane jacket can, for example, be made from a set, precatalyzed material manufactured by Arnco in South GaIe, California / USA under the trademark "Catapol" is available. The material is at 160 ° F Preheated for about 5 hours, then poured into a mold around the roller core, and finally at 280F Heated for about 8 1/2 hours and finally cooled down before grinding and polishing.

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A suitable rubber cover can, for example, from Mid-America-Roller Company, Arlington / Texas, USA, under the name "Buna-Nitrile", which is conventionally obtained via attached to the core and treated with a high speed abrasive prior to polishing will.

After an elastic jacket 4 4 made of urethane or rubber or the like. has been formed, the roller can be a have, as it were, smoothed or "shiny" outer skin, which is removed by grinding. To a grinding treatment with a 120 grit grinding tool can the surface of the elastic jacket 44, if it is made of urethane, with 180 grit sandpaper treated to provide a surface of uniform smoothness on the surface 4 5 of the elastic Sheath 44 to form. Meanwhile, if the elastic sheath is made of rubber, it may be subjected to grinding treatment Using a 120 grit tool the rubber can be treated with 400 grit sandpaper to make a to create a velvety smooth, uniformly textured surface / which is free of "orange peel structure" or other irregularities.

Microscopic reservoirs in which paint is held help ensure that a continuous, unbroken ink film remains on the surface 45 of the applicator roller 40.

Surface scratches, sanding lines and other surface irregularities should be removed so that the surface roughness - whether there is

the sheath is made of urethane or rubber - after treatment with sandpaper Does not exceed 30 RMS. As will be explained in detail below, the adhesive forces between the color molecules and the molecules of the surface 45 of the jacket 44 is the cohesive force between exceed the paint molecules in order to enable the paint to shear off and a controlled, continuous, to be able to form an unbroken paint film on the surface 45 of the applicator roller 40.

It is known that it is extremely difficult, if not impossible, to make the roller 40 so that the Surface 45 is perfectly circumferentially round, and remains so, continues to be is perfectly straight in the longitudinal direction and that it is ultimately concentric in a precise manner to the axis of the roller core 42. The straightness or waviness of the surface 45 of the roller 40 can be economical with a tolerance of about 0.002 inches (about 0.05 mm) along the length of the roller and the radial eccentricity can be within a tolerance of about 0.0015 inches (approx. 0.038 mm).

A Shore Α hardness test is generally used to measure the hardness of an elastic roll shell, wherein the resistance to penetration is at a constant temperature of about 76 ° F with the roll mantle stationary is measured. The hardness of an elastic surface under dynamic conditions gives way completely depends significantly on the hardness measured in the hardness test under static conditions. The spring rate of a

elastic material increases as little as the deformation increases.

If the stress frequency of an elastic component increases, the dynamic module or the Modulus of elasticity, which means that the jacket is made of a harder, stiffer material appears. However, a cyclic or periodic alternating stress on an elastic material has result in the generation of internal heat, which increases the temperature and a decrease in hardness and accordingly results in the modulus of elasticity of the elastic jacket.

Since the surface 45 of the roller 44 is preferably in mutual pressure engagement with the surface of a Plate cylinder is, the plate cylinder has one extending in its longitudinal direction Gap, whereby this cyclic or periodic stress generates an uneven heat generation Extent in the circumferential direction of the surface 4 5 results. Such temperature differences at the Surface 45 can experience a noticeable change in the radial distance from the axis of roller 40 too Points of the surface 4 5 result, since the coefficient of thermal expansion of elastomeric materials, which are used to form elastic roll mantles that are several times higher than the coefficient of thermal expansion for example of steel.

As stated, the roller 40 can be different in diameter than the plate cylinder P, without that thereby the printing of a color film 130 on

a web W or a sheet is adversely affected, since the metering member 1O a continuous Ribbon produced on the surface 4 5 of the applicator roller 40, regardless of the previous one Indentation and independent of the temperature fluctuations in the roll jacket 44.

The applicator roller 40 should not have the same diameter like the plate cylinder P, because in such a case even the slightest defect, a hole, crack or the like. on the surface of the applicator roller 40 would repeat at the same point on the disk if both were at the same peripheral speed are driven and have the same diameter. Such a repetition can in particular adverse effects when printing a lithographic plate on the non-image portions to lead. Such a crack or the like. can namely on a printed sheet or the like. in one Non-image section appear as color. If such an irregularity occurs in a portion of the image, too much color could appear accordingly. Accordingly, it is most convenient to Needless to say, the surface of the applicator roller 40 does not coincide with the plate surface of the plate cylinder repeatedly. It has been observed that when such a repetition fails occurs, said irregularities of a lithographic plate in a non-image portion not affect, even if such an irregularity is relatively severe is trained.

"Ir

The support device

The support device 5 for supporting the lever arm-shaped metering member 10 according to FIGS. 1 and 2 has an elongated support beam 50, one side of which is ground and really has flat surface 52, and a relative to the flat surface 52 inclined surface 54, the forms a shoulder 50 which extends along the support beam 50. Bearings 56 extend from the opposite ends of the support beam 50 and are rotatable in self-aligning, not shown bearing bushes 57 mounted in bearing blocks 60, which outwardly extending projections 58 adjacent to the opposite ends.

An elongated slot is formed in each of the projections 58 through which anchor bolts pass 52 ′ for fastening the bearing blocks 60 to the inking unit side frame 2.

As can be seen from Fig. 1, four jack screws 64 extend through threaded bores in the projections 58 on the bearing blocks 60 and are in engagement with a surface 65 of the inking unit side frame 2, in order to be able to move the support beam 50 in the vertical direction.

Transverse adjustment screws 66 extend through threaded bores in outwardly extending lugs 68 of the inking unit side frame 2 and stand with end faces 66 'of the projections 58 in engagement.

JjZ-

From the foregoing it can already be seen that the position of the bearing blocks 60 in vertical and Is adjustable in the horizontal direction, as can be seen from Fig. To the support bracket 50 relative to the Axis C of the roller 40 can be adjusted.

An arm 70 is bolted or otherwise to the end of the bearing 56 on the support bracket 50 and secured by a piston rod 71 of a fluid pressure actuated cylinder 72 against to push one end of a stop screw 7 4 that is screwed to an arm 75 or otherwise having it the bearing block 6O is connected. It can be seen that the support bracket 50 is relative to the bearing block is rotatable relative to arm 75 by adjusting the position of the end of stop screw 74.

A pressure regulator R "is installed to adjust the intake pressure in the cylinder 52 to be sufficient is large to hold the arm 70 firmly against the screw 74 at all indentations of the Edge 25 into the surface 45 of the shell 44.

The metering member 10 is attached to the flat or planar surface 52 of the support beam 50 by screws 7 6, which extend through spaced apart openings in a clamping member 78, as well as oversized openings that extend through the adjacent to the rear edge Extend lever arm. The screws 76 are in threaded holes of the support beam 50 screwed in. The screws 76 and the clamp member 78 operate in this way together that the metering member 10 evenly on the

Support bracket 50 is attached or is supported by this, so that the edge 25 is uniform over its length Has spring property.

In the embodiment of the device according to FIG. 1, the stop screw 7 4 is driven by a direct current motor 80 remotely controlled, which is attached to the arm 75 by a support bracket 81. Between the engine 80 and the screw 74 a reduction gear is arranged to increase the speed of rotation of the screw 74 continue to steer. Between the screw 74 and the output shaft of the motor 80 is one with both connected splined coupling or the like. 76 'arranged. A suitable motor 80 is commercially available, for example from Globe Industrials Division of TRW, Inc., Dayton, Ohio / USA.

Connection lines 82 and 84 extend between the motor 80 and a control unit 85 for controlling the motor position, the control unit 85 of is of conventional construction and includes a DC power source and a three-position switch.

The control unit 85 for controlling the motor position has a digital display device 86 by means of which indicate the position of a rotary potentiometer (not shown) at the end of the stop screw 74 which cooperates with arm 70 to provide a visual indication of the posture of the support beam 50 for the dosing member 10 zu sch.afferu The motor control unit 8 5 i ^ i ^ feeTT ^ Hemin shown in the drawing Embodiment attached to the side frame 3 of the printing machine. An additional or

however, another motor control unit 85 is preferably adjacent to the delivery end of the printing press or on a control console arranged so that the position of the metering member 10 can be adjusted remotely can, when inspecting printed sheets, adjust the color density across the sheet as required or desired to adjust.

The inking unit side frames 2 are pivotally mounted to the printing machine side frames 3 by a shaft and are adjacently mounted on opposite sides of the printing press. A fluid actuable fitting 92 is pivotally mounted to protrusions 93 attached to the side frame 3 of the printing machine , and has a piston rod 94 pivotally connected to a shoulder 95 which is welded or otherwise connected to the inking unit side frame 2. A one-stop single screw 96 is screwed into a shoulder which is connected to is connected to the press side frame 3 and arranged to engage the inking unit side frame 2 when pressure is ^{properly achieved between the surface of the form roller 40 and the printing plate P 1.} An off-stop single screw 98 is in a lug screwed in, the JL-connected by welding or "in some other way with the printing machine side frame n is and stands with deffl ~ -F-Ä2rbwerks-TiriS when the piston rod

of the release cylinder 92 extended ^^^ S ^ öötä while the surface 45 of the application roller 40 separates from the surface of the printing plate P ¹ .

As stated above, the page boundaries 6 pressed into sealing engagement with the opposite ends of the applicator roller 40 and delimit the opposite ends of the paint supply R. A paint retaining wall 100 is in sealing engagement with the surface 45 of the applicator roller 40, as shown in FIGS. 1 and 2 of the drawing and their opposite ends are at the side boundaries 6 attached. The lower edge 102 of the paint retaining wall 100 is preferably slightly off Distance to the surface 22- of the paint metering member 10.

The color retention arid 100 delimits the entrance side of the ink supply R. The outlet or outlet side of the ink supply R is limited by a component 105, which is fastened to the support beam 50 by means of screws 106. A lower seal 108 adjacent the component 105 is arranged adjacent to the upper side 28 of the metering part 10 to allow a flow of paint also to prevent the upper side 28 of the metering part 10 from the paint supply R and to form a stagnation area in which paint stops flowing or to flow. Since lithographic ink is thixotropic, the ink viscosity is considerably reduced, when paint is in motion compared to the viscosity of paint at rest.

As shown in Fig. 1 of the drawing, for the sake of simplicity, a stirrer is also used below designated component 110 attached to the paint retaining wall 100 in order to access the paint in the R supply To act on the color. The stirrer 110 is commercially available

for example from Baldwin-Gegenheimer, Stamford, Connecticut / USA, and has a pinion-rod gripper drive (not shown) which extends in the longitudinal direction over the upper section of the ink supply R and carries a mixing head, which is driven via a chain by a motor at constant speed. When the mixing head approaches a side boundary 6, which is located at the end of the application roller 40, it reverses one direction of movement and moves to the other end of the ink supply R. The stirrer 110 rotates in the Paint in order to stir it in the transverse direction or to exert shear forces on the paint and viscosity irregularities to prevent along the color supply.

Commissioning and operation or function

The working and functioning of the device described above is as follows:

The metering member 10 is aligned by means of two bolts or pins 51 which are pressed into the support beam 50 and extend through precisely arranged, aligned bores in the metering member 10. The dosing member 10 is attached to surface 52 of support bracket 50 by screws 76. The pins 51 in the Support brackets 50 extend through bores in the metering member 10 and provide a uniform overhang of the metering member 10 safe over its length and accordingly also a uniform bending and stress or application of force on the edge 25. The anchoring screws 52 are first solved to a

Mobility of the bearing block 60 relative to the inking unit side frame 2 to enable.

The lifting screws 64 are provided to support the surface 52 to align parallel to the axis C, and to the angular relation between the support surface 26 of the (actual, underlying) metering part 10 ″ relative to a tangent to one through the edge 25 extending radial line of the application roller 40 to be able to adjust.

The transverse adjustment screws 66 are provided to the Move bearing block 60 relative to application roller 40 to be able to, and to align the edge 25 of the metering member 10 relative to the surface 4 5 of the elastic jacket 44 of the applicator roller 40 to enable.

After the edge 25 of the metering member 10 is aligned with the surface 45 of the applicator roller 40 and the angular relation between the surface 26 and a tangential line to the applicator roller 40 is established has been tightened, the anchor bolts 42 'that secure the bearing blocks 60 to the Fasten side frame 2.

As can be seen from FIGS. 1 and 3, the edge 25 of the metering member 10 now penetrates the surface 45 of the jacket 44 of the roller 40 at a point P " around 11 o'clock, i.e. in the 9-12 o'clock quadrant, if one assumes that 0 and 12 o'clock is at the top of the applicator roller, and that one the designation like a dial in the clock

selects pointer senses. The paint reservoir R is accordingly designed as shown and naturally causes, due to the force of gravity, that paint rests or is located on the edge 25 of the metering member 10, whereby a complete fusing of paint on the front side of the metering member 10 on the surface 4 5 of the jacket 44 of the roller 40 at point P "is ensured. The edge 25 is now brought into" kissing contact "with the surface 45 of the applicator roller 40. An amount of paint that is greater than that required for continuous coloring of the plate P ¹ on the Plate cylinder P is required, is made available by the ink supply R of the surface of the application roller 40, which approaches the metering surface 24 of the metering member 10.

After the edge 25 has been brought into "kissing contact" with the surface 45, the stop screws 74 rotated, whereby the support bracket 50 from that shown in solid lines in FIG Position is rotated into the position shown there in dash-dotted lines.

This leads to a bending of the cantilever arm and the flexible, polished edge 25 is in pressure engagement brought with the elastic surface of the applicator roller 40 and adapts to this accordingly. A rotation of the roller 40 now continuously moves ink from the ink supply R into contact with the Dosing surface 24 and the edge 25. In this way, paint is applied in sufficient quantities to the surface 4 5 Sheared off to a color film 130, as it were, the thickness of which can be changed, like this one

is set out in detail below.

Assuming once that the edge 25 is firmly supported at one end of a cantilever arm, so is the Function for the bending line

Y = F (2L ³ - 3L ² x + x ³ ) 6EI.

In a prototype, the distance between the shoulder 55 and the metering edge 25 of the metering member 10, which would correspond to the unsupported end of the cantilever arm, was 1.625 inches (approx. 41.3 mm), the distance between the surfaces 28 and 28 ^f was 0.035 inch (about 0.89 mm) and a static load of 25 ppi wide (about 4.46 k / cm) was applied to the edge. The support width S was 0.15 inch (approx. 3.8 mm). The modulus of elasticity E of the metering member was about 30 10 psi.

The moment of inertia I of a rectangular surface is

12,

where b is the base length of the rectangular surface and h is the height of the rectangular surface. The moment of inertia I of the metering member 10 with a thickness of 0.035 inch wi:
of the cantilever.

- 6 Thickness of 0.035 inch becomes 3.5 χ 10 per inch of width

At the unsupported end of the cantilever arm is χ 0 and the deflection is Y

FL ³
3EI.

Accordingly, it was calculated that the deflection of the unsupported end of the cantilever would be about 0.31 inches (about 7.87 mm) with a 25 ppi load applied to edge 25. Accordingly, it was concluded that the spring rate for the cantilever would be 0.012 inch deflection per pound of force (0.4536 kgf) ( - on the edge 25 or 81 pounds per inch deflection over one inch width of the edge 25.

It should be noted that the calculation of the bending line, as it has been explained above, only one Can be an approximate value for calculating the curvature of the edge 25, which the metering member 10 is not entirely accurate is firmly supported or clamped on the shoulder 55 of the support bracket 50, and since the 0.035 inch The recess does not extend all the way to the shoulder. However, it can certainly be seen without further ado that the edge 25 is acted upon elastically in the radial direction to the applicator roller 40.

The bending or the distance covered by the edge .25 of the metering member 10 was in the case of the above Example actually measured to be 0.14 inch (about 3.56 mm) when an average static force of 25 ppi was applied to the edge 25. A division of the force of 25 ppi by the curvature of the Metering member 10 gives approximately 178 ppi bend. The result of the actual bending of the elastic Dosing member 10 calculated spring constant differs from the above approximately calculated spring constant.

The differences between the approximately calculated and actually measured spring constants have already been identified predicted.

The wide support width S of 0.15 inches (about 3.81 mm) was chosen to provide an adequate support surface corresponding to the large 25 pound force acting on the support surface 26 of the metering member 10 and on the Jacket 44 of application ^{roller 40 in the section indented with N 1} on the ink film produced at the metering edge 25 in order to create a pressure in the area N 'which is sufficiently great to cover the entire surface 26 and both edges 25 and 28b in the surface 45 of the jacket 44 of the application roller 40 to be pressed. Static indentation was measured to be about 0.06 inch (about 1.52 mm), but this immediately changed to 0.04 inch (about 1.02 mm) when an applicator roller with a hardness of 60 rotated the one Jacket 0.5 inch (about 12.7 mm) thick. It would accordingly be concluded that a certain force is required for a desired bending of the edge 25 on the collar portion of the metering member, and that a certain support surface is required for this force, which creates a pressure which is sufficiently great to a certain roller shell around a to press a sufficiently large amount, and around a wedge or the like between the roller surface and the metering surface on the first edge of the metering member 10. to form to dose a certain color of known viscosity to a desired film thickness when the film leaves the rear (second) edge of the support surface of the metering member. In general it can be said that low

Edge bends require small forces in order to obtain the small bending, and that a support can then take place by means of a correspondingly small support surface in order to achieve a sufficiently high pressure for the indentation into a certain jacket to a desired extent. Large bends require correspondingly large forces in order to obtain the desired large bend, but a correspondingly large support surface must be available in order to achieve the same pressure and the same indentation with one and the same jacket. Accordingly, FIG. 3 shows both, namely a large support surface width S and a small width S ·. S is greater than t, namely approximately 2t, while S ^{1 is} equal to or less than t, namely approximately equal to t in the illustrated embodiment. Satisfactory results have been obtained with values of S between t and 2 t. Relatively large edge deflections are also desirable in order to create a system which does respond to a change in the position of the stop screw 74, but which in turn does not respond too sensitively to this.

As will be explained in detail below, is the combined distance that the Edge 25 is bent, plus the distance by which the edge 25 is pressed into the roller surface 45 is, preferably substantially larger than the maximum space between points on the roll surface 45 and the edge 25 when the surface and the edge are in "kiss contact". For example may be irregularities or manufacturing inaccuracies of the roller surface 45 and a minor Waviness of the edge 25 slightly to a maximum

A deviation of 0.002 inches (about 0.05 mm) so that the surface 45 and the edge 25 do not come together are compliant when they initially touch. When the edge 25 is bent 0.16 inch (about 4 mm), and is indented 0.04 inch (about 1 mm) into surface 45 under dynamic conditions, that would be initial deviation of 0.02 inch only 1% of the combined distance of 0.20 inch (approx. 5.1 mm). Since the edge 25 and the jacket 44 are elastic, they behave flexibly and can adapt to one another. After such adjustment, the pressure along the touch strip N is substantial constant and the effect on the color film is negligible with regard to the small differences.

This combined distance between bending and indentation under dynamic conditions is a hundred times the original deviation, so that the maximum error after the edge 25 has been pressed against the surface 45 is only 1%. Accordingly, changes in pressure and indentation in the area N become negligible. As a result, a color film thickness is maintained which is considered by printers to be more than acceptable for uniformity of color density. As is well known, printers describe a control as very good if the color density is not more than -5% above di <
printed sheet varies.

rather than - 5% over the surface of a

As shown in Fig. 3, the edge 25 of the metering member 10 is so in the surface of the applicator roller 40 pressed in that the elastic material is formed as it were bead-like, with upstream

to the surface 24 a small bead or a wave is formed in the jacket 4 4, while downstream to the edge 25 in the jacket 44 a kind of groove or a channel 27 'is formed. The section before the Surface 24 forms a wedge through which paint is drawn. The wedge is on one side through one Section of the surface 24 and the edge 25 bounded and on the other hand by a portion of the Surface 45, probably between a small portion of the bead 120 and the portion of the surface 45 immediately adjacent to the polished edge If the cantilever arm of the flexible edge 25 allows, to follow the contour of the applicator roller, the wedge automatically moves somewhat radially relative to the Axis C of the applicator roller 40. Since the wedge by cooperation of the opposing, under Bias flexible deformed edge 25 and the elastic surface 45 of the applicator roller 40 formed this movement is desirable when there is a constant pressure relation on the through the opening extruded color should be maintained. The surface of the applicator roller 40 is constantly changing Contour when the roller rotates, due to its 'elastic memory', temperature fluctuations and variations in the dynamic modulus of elasticity, as discussed above has been. Accordingly, it is important that the edge 25 automatically move radially and longitudinally can deform flexibly in order to adapt to these contour changes.

The elastic edge 25 of the metering member 10 and the elastic jacket 4 4 of the roller 40 can be at a

certain point of view can also be viewed as two opposing springs, each with a spring constant K ₁ or K _? have, the common or total spring constant then being calculated to

K = ^K 1 ^XK 2

This common spring constant K is less than each of the spring constants K ₁ or K ~. Table 1 below and the resulting calculations demonstrate the above finding that the total spring constant K is lower than the individual spring constants K ₁ or K ₂ . The table also shows that the original 0.002 inch deviation or the corresponding error only results in a final pressure difference of about 1% of the static or dynamic pressure.

S3

Table I.

data
part F =
force
(I / In) A =
area
(In ² ) P = F / A
Pressure"
(# / In ² ) D =
Bend
(In) K = F / D byast.
Spring bed
constant
(lb / in) Dosing
element M.
25th M.
.15 C.
167 M.
.14 C.
178 ₍ static a coat
order
roller M.
25th M.
.15 C.
167 M.
.06 I.
C.
417 j
(for 0.15 in.) Dosing
element C.
28.6 M.
.15 C.
191 M.
.16 C.
178. dynamic a coat
order
roller C.
28.6 M.
.15 C.
191 M.
.04 H
C.
715
(for 0.15 in.)

factually

178 + 417

=

^{E (%)} static ⁼ ( ⁰⁰² >< ¹²⁵ > x TOO (167) (.15)

K.,. ._, = (178) (715) = 143 # / lN,

'dynamic

178 + 715

dynamic

⁽¹⁴³ >

100 = 1

(191) (-15)

M = measured C = calculated

accordingly E (%) = + 1/2 2

Accordingly, the actual metering part 10 ″, i.e. the working end of the metering device 10, which is from the surfaces 22, 28a, 26 and the line 28 "is limited or is formed, a right-angled cross-section, which includes the metering surface 24 and the edges 25 and 28b, and can be spring loaded by any other means be, which the same function as the cantilever portion of the dosing member 1O on it exerts, i.e. the working end is elastic over its entire length in the radial direction and in the tangential direction Direction firmly or rigidly supported. When the surface 24 is formed on the rectangular section is, the working end of the metering member 10, as this can be seen in Fig. 4, forms one as it were trapezoidal section 10 ".

It should be noted that the color carried by the surface 45 of the applicator roller 40 on the (as it were acting as a kind of weir) metering surface 24 strikes or impinges on this, and that the surface forms a section of turbulent flow adjacent the bead 120 on the resilient roll surface. It follows that although the edge 25 is elastically depressed, as can be seen in FIG is, the metering surface 24 is shaped and positioned, and that the edge 25 is sufficiently elastic biased against the roller 40 presses to a change of the film 130 by hydrodynamic forces to cause that are exerted on the metering member 10 by the paint. This condition will also be assisted by positioning the polished edge 25 so that it is closer to the central axis C of the applicator roll or this itself lies as any other

Point of the support surface 26 of the metering member 10. The obtuse, obtuse-angled polished edge 25 preferably deforms the elastic jacket of the applicator roller with the formation of a metering wedge angle W between the Areas 24 and 120 for forming a color film of precisely controlled thickness, which has approximately a pressure profile, as shown in Fig. 3, where the maximum pressure is on the front dispensing edge.

The surface 28a of the metering member 10 is positioned immediately downstream of the support surface 26 so that the metered or metered ink film is only in contact with the metering member 10 along the support surface 26, and that the ink film 130 immediately separates from the metering member at the edge 28b in order to prevent paint moves along surface 28a, resulting in build-up of paint, dripping and eventually random flow which would destroy the uniformity of the paint film 130.

The underside of the metering member 10 is designed so that the surface 28a on the "heel" or edge 28b of the polished surface 26 and the at least partially enclosed recess section 27 is at an angle relative to the direction of movement of the ink film 130, so that the roller surface 44 cannot deform back into a position in which the color film 130 contacts the surface 28 'or collects and builds up on the surface 28a.

Accordingly, in the embodiment according to FIG. 3, the metering member 10 is shaped and arranged so that the

see p

The ink film 130 immediately moves away from the metering member 10 separates when the roll shell moves into the relaxed, un-depressed position.

Referring to Fig. 3, it should be noted that the edge 25 is shown so that it is a dimension d is pressed into the surface 45 of the applicator roller 40, the original radius R of which is a surface speed V, a jacket thickness T and a hardness D.

The metering member 10 shown in Fig. 4 has a support surface width S, a thickness t and a recess height r, which (at this point) leaves a cantilever lever height of (t ./. r). The distance L refers to the cantilever lever and the dimension 1 denotes the length of the recess. The metering surface 24 is at an angle B. employed at a height (T ./. h). The angle A. denotes is the total included obtuse angle between surfaces 24 and 26 and is 90 + B.

Referring again to FIG. 3, it should be noted that the angle A _{3 represents} the slight angle of incidence of the support surface 26 to a line parallel to a tangent to the roll radius R, which is determined by the indentation measured from the point P ". The point P" denotes the point of intersection on the radius R of the surface 45 of a radial line and a tangent to the roller. The angle Ao is preferably 0 ° or slightly greater in order to ensure that the edge 25 is indented by an amount which is equal to or greater than any other point on the support surface 26. The gap N is a measure of the color

between the support surface 26 of the metering member 10 and the pressed-in roller surface in the zone between the edges 25 and 28b, which is represented by the support width S. Indeed, the thickness of the nip N is substantially equal to the thickness of the ink film 130 produced behind the edge 28b on the roller surface 45, which will vary according to the parameters discussed above. A- is the angle between the metering surface 24 and a radial line running through the point P 2 *. We have λ ^^ U T ^ XIn.

The angle W is the wedge or entrance angle between the surface 24 and a tangent an imaginary circle or curve with a surface 120 moving towards the edge 25.

It is generally believed that the pressure on the edge 25 and the angle W determine the thickness of the color film 130 essentially determine u for a given liquid viscosity.

The resulting pressure effect of such a metering member 10, which properly in conjunction with a elastically coated applicator roller 40 is used, is that the surface 45 of the roll shell 44 generates a pressure profile which is considerable differs from those that arise in the known prior art in metering devices with cooperate on their outside elastic application rollers. In contrast to the prior art, in which the Pressure gradually rises to a maximum at a trailing edge and quickly falls to zero, like this at

3225382 SS

conventional blade scrapers for coating Paper etc. is the case, the invention disclosed here has the effect, as can be seen from FIG. 3, a more or less sudden increase in pressure on the roll shell, since the obtuse-angled first resp. leading edge 25 is pressed into the incoming, rotating roller, the pressure being a point or a Maximum P reached and then quickly drops slightly when the roller has passed the edge 25 and below the support surface 26 of the metering device 10 arrives, and the pressure then rapidly decreases again to 0, when the roller or roller surface leaves the rear edge 28b of the metering member 10. Something else This way it can be said that the maximum pressure P "of the metering member 10 according to the invention at the obtuse-angled, first or forward dosing edge of the dosing member 10 is reached, and not at the second edge of the metering member, that is to say the rear edge 28b, as is the case with known paper coatings the case is. In cases in which in the known state of the art for paint metering devices, too Pressure increase at a first edge may be achieved, it has not been recognized that also a important second edge must be provided, as provided here according to the invention, in the elastic Surface of the roller is pressed in to prevent that generated by the metering edge located in front Dosing effects cannot be destroyed again afterwards.

Furthermore, when positioning and supporting the two mentioned edges along their lengths, such as ■ this is provided here, it is important that the edges are firmly supported in the tangential direction, and that the support in the radial direction

is flexible, whereby these two features work together and in common an automatic dispensing consistency and -Create uniformity when the roller rotates and even when the speed of rotation varies.

During testing of the device described above, it was found that if the Force which initially increases the edge 25 in compressive engagement relative to or with the surface 45, the Thickness of the film 130 decreases to a minimum thickness, and then, as the pressure continues to increase, the film 130 grows again while remaining uniform or will.

From Fig. 5 it can be seen that this surprising phenomenon occurs when the edge 25 of the Cantilever-shaped metering device 10 acting force in the direction of the surface of the roller 40 increases. If a small force per unit linear length of the edge 25 was applied to the edge 25 in Pressing the face 45 into pressure decreased the color density. With this low application of force however, the color density was not uniform across the length of roller 40. When the force was increased, the thickness of the ink film on the roller was decreased to some degree of greater stress along the length of the edge 25 per unit of length had been reached. The paint film thickness then began to grow when the applied to the polished edge 25 in the direction of the central axis C of the roller 40 Force has been increased. In other words, as the force grew, the film thickness became first diminished and then began to increase when the

-SA-

Load was further increased. However, it became the Ink density extremely uniform in the transverse direction along the length of the roller 40 and in the circumferential direction around it, when the applied load has an average static force of 25 ppi on the edge 25 and the support surface 26 exerted. Area 26 was 0.15 inch (about 3.81 mm) wide. the The thickness of the roll shell was 0.50 inch (approx. 12.7 mm) and the hardness was 60 Shore A. The resulting The indentation was 0.04 inches (approx. 1.02 mm) and the roll radius was 5-1 / 8 inches (approx. 13 cm; s. Table II, Example I).

This phenomenon in which, at a pressure threshold, the ink film thickness suddenly begins to decrease and begins then to increase as the force on the edge 25 becomes higher has been observed when the edge 2 5 the is the lower front edge of a cantilever-type metering member. Fig. 3 shows such a metering member 10 in one such indented relation to the surface 4 5 of the roller 40 in a position in which the edge bending stress, the pressure (which determines the indentation) and accordingly the ink film thickness (which determines the color) are essentially constant.

Referring to Figure 5, it can be seen that the paint film thickness 130 as a function of the indentation of the polished Edge 25 in the elastic surface 45 of the jacket 44 of the application roller 40 varies. As above has already been described, as the indentation increases, the thickness of the paint film 130 rapidly increases to a minimum and then begins to increase again.

grow. Irregularities or imperfections on the surfaces of the metering device 10 and the applicator roller 40 are easily recognizable in the metered color film 130, up to the polished edge 25 up to a Point is indented, in which the change in the initial relation edge to roller along the length of edge 25 is small compared to the total bend, e.g. less than -5%. At this Point, the paint film becomes more uniform and uniform and remains substantially uniform when the polished edge 25 is bent further and pressed into the surface 45 of the applicator roller 40.

It was observed that the minimum ink film thickness corresponds to the minimum in the curve of FIG. 5 in is determined primarily by the pressure on the edge 25 and by the angle of the metering surface 24 relative to the roller surface 120, which in Fig. 3 for a certain Color viscosity is indicated with W.

With reference to FIGS. 3 and 4 of the drawing, it should be noted that the metering surface 24 is determined by the angles B and A, so that the metering surface 24 extends counterclockwise in the direction of the bead 120, as shown in FIG is recognizable. The minimum film thickness according to the curve in FIG. 5 is determined for a certain roll hardness and thickness, metering member support surface width, load (= pretension) and paint viscosity. Accordingly, when the obtuse angle A _{1 of} the metering member 10 and the positioning angle A ″ between the metering surface 24 and a roller radius change, a family of curves according to FIG. 5, as shown in FIG. 6, is obtained.

-Se -

From the previous explanations with simultaneous reference to FIG. 6, it follows that an angle A ~ can be selected and that, accordingly, the obtuse angle A ~ can be determined so that the desired Film falls well within the stress range that produces a uniform film 130 with no significant indentation and without a sharp formation of the angle A-, which produces heat and rapid destruction the metering edge 25 and / or the roller surface.

It was also observed that the thickness of the film increased by changing the viscosity of the paint in the paint supply R located color can be changed within certain limits. Accordingly, by adjusting and controlling the temperature of water or other liquid passing through the tubes 7 and the line 5 'flows in the support beam 5O, the paint viscosity can be changed in the color supply R in order to increase the color density affecting the coloring change or adjust. The viscosity or the flow properties of the paint can be used for a certain change The coloring can also be changed by means such as so-called reducers and / or extenders.

From Fig. 6 it can be seen that the lowest available color thickness as a result of a certain angular Relation between the metering surface 24 and a radius of the roller 40 can be that Color disappears completely from the surface 4 5 of the roller before the point at which the film thickness disappears begins to rise again. Accordingly, rapid wear on the surface of the roller 40 and / or to prevent the edge 25 of the metering member 10,

should be an angle Λ. be chosen as shown, i.e. e.g. 30 ° to provide uniformity while at the same time providing minimum and maximum film thickness without excessive pressure being added to considerable indentation and rapid wear.

A curve and, accordingly, an angle A ₂ and, in a corresponding manner, angle B are selected with which the minimally desired coloration can be achieved, the minimally obtainable film being achieved approximately at the same time. For example, angles A ~ = 15 ° and A "= would not reach this parameter. When using inks for lithographic offset printing on coated material, the generally recommended or desired color density is 1.25 for cyan, 1.30 for magenta, 1.60 for black, and 0.90 for yellow. The range should be around - 15 di.
wear.

- 15 dense points or a total of 30 dense points

Printing ink is generally an oily, viscous substance that is very heavily pigmented and can be referred to as sticky so that the paint properly adheres to the print sections as intended adhering to the printing plate. Ink commonly used for printing newspapers, has a viscosity in the range of 50 to 80 poise. Color commonly used for printing on printing machines used, as well as ink for offset printing on webs, has a viscosity of the order of magnitude from about 150 to 200 poise. Ink used in lithographic offset printing of sheets, generally has a viscosity of about 250 to

- jKs -

σι

300 poise.

If there are different viscosities, the curves labeled 0 °, 15 °, 30 °, 45 °, 60 °, etc. in FIG. 6 no longer apply as shown. Accordingly, FIG. In the manner shown only applies to special design parameters of the roller and the metering member and the flow behavior or the strength of a certain one
used color. For a more fluid color than her
be used in lithographic sheet-fed printing, for example a color such as that used in black
Newspaper printing in printing machines or the like. is used, for example, the angle required to produce an acceptable color density for direct lithographic printing on newsprint or the like. in
of the order of 60 ° instead of 30, as has been chosen above. For extremely viscous, very
solid colors one would choose smaller angles A "in order to
to get the desired print results. Accordingly, one can easily find optimal angles for A. and accordingly B, since A should be ~ O ° or something
larger after the design parameters for the
Application roller 40 and the metering member 10 are fixed for certain films and required viscosities “what
enables one to produce the color to be produced without noticeable indentation, which leads to premature coat-
and edge defects on the application roller or on the metering member would result. It should always use the largest possible angle A ₁ and B, ie the obtuse angle of the metering member 10 to achieve the desired
Realizing results.

Adjacent due to the construction of the metering member

to the ink supply R, the flow of ink in the ink supply to the metering member is turbulent, which has the consequence that Lint or other foreign matter will generally be rejected by a high pressure section like him is present immediately adjacent to the front edge of the metering member. Such lint or the like. will be in held back by the turbulent eddy of the paint reservoir, thereby increasing the pumping of frend particles the dosing edge of the dosing member is minimized. Color due to the movement of the surface of the elastic roller flows or is transported in the direction of the first polished edge of the metering member, causes an almost instantaneous increase in pressure, and the turbulent flow becomes immediately adjacent to the first polished edge is laminar. The paint is sheared off as it were when it is through a wedge between the elastic surface of the roller and the metering surface of the metering member adjacent to the first polished edge moves.

The polished support surface 26 and the edges 25 and 28b of the metering member 10 have been turned towards the elastic surface 45 of the applicator roller 40 pressed by means of a force which is sufficiently great to to depress the roller surface 45 along the length of the edges 25, 28b and along the length of the roller surface 45. The required indentation depends on the desired color thickness, the modulus of elasticity of the elastic roll shell 44, the thickness of the elastic roll shell 44, the temperature, strength, the Adhesion behavior and the viscosity of the paint as well as others related to the flow properties of the paint Properties, the texturing of the roller

surface, the condition and, if applicable, the arrangement of the front edge of the metering element, the width of the support surface, the angle of the metering surface of the metering member, the position of the support device relative to a tangential to the roller line, the pressure between the application roller and the adjacent plate, the Conditioning of the paint before and after application to the plate, as well as that in the paint to be dosed existing solution and any added solution to the paint to be dosed. The polished edges of the dosing element are slightly pressed into the surface of the elastic roller, for example 1/30 inch for a roller with a surface hardness of 60 Shore A and a jacket thickness of about 1/2 inch (approx. 12.7 mm). When the roller rotates, the polished edges of the metering member move relative to the axis C of the Roller 40 to maintain a state of equilibrium so that the edges 25, 28b automatically move move radially along their length relative to the axis C of the roll surface and in the circumferential direction to this, although the roll surface 45 is not ideally round and not free from slight waves.

Figure 7 shows schematically what has been discussed above Phenomenon which is that the uniformity of color density on a printed Sheet grows when the force with which the edge 25 under elastic pressure into the surface 4 5 of the Roller 40 is pressed, grows.

As described above in the comments relating to FIG. 10 of the drawings, the density of colors printed on a sheet of paper via the

- & - 67

Surface of the arc measured at distributed points. Maximum and minimum color density readings were made registered. Arches were selected which are applied to the edge 25 of the metering member 10 with different applied bias force had been printed to vary the color density over the entire sheet.

It can be seen that the difference in color density between the maximum and the minimum is about the entire sheet decreased when the force with which the polished edge was in relative pressure engagement with the elastic roll shell 4 4 of the roll 40 had been pressed, grew, as this through the lengths of the Lines D-, D ~, D ^ and D. in Fig. 7 have been indicated is.

It can be assumed that the dosing member 10, which is designed as a cantilever arm, has been bent when a force acted on the edge 25 to bring it into relative compressive pressure engagement with the surface 45 bring, and when that power had been increased. The elastic jacket 44 of the roller 40 has been deformed or pressed in, and the edges 25 and 28b were slightly deformed along their length, so that the edge 25 and the surface 45 of the roller 40 have been matched to one another in the immediate vicinity of one another, although the edge 25 and surface 45 of the roller when positioned in "kiss contact" will not be in ideally compliant. Accordingly, the deformation or bending of the metering member 10 carries the deformation or bending of the edge 25 along its length and the indentation of the skirt 44 all contribute to this the proper ink film thickness and uniform

6 /

Color density across the surface of a printed sheet to obtain.

Referring to Figs. 5 and 7 of the drawings, it should be noted that the color film thickness is limited to Minimum drops and then begins to grow again when the force engaging the edge 25 under pressure brings in relative indentation to the roller surface 4 5, grows. Accordingly, dnc is the same color film thickness at two different points on the curve. However, like this is by the different ones Lengths of the lines D ^ and D. in Fig. 7 of the drawing is indicated, the change in color density the two curve points different.

Referring to Figure 8 of the drawings, it should be noted that a dial gauge has been attached to the support bracket 50 and brought into engagement with the top surface 28 adjacent the metering surface 24 of the metering member 10. When the applicator roll 40 was rotated, an entire dial gauge reading of 0.002 inches (about 0.05 mm) was observed. This indicated that the out-of-roundness of the radius of surface 4 5 of roller 40 was 0.001 inch (about 0.025 mm), and that the edge 25 of metering member 10 boj increased 0.0025 inch (about 0.25 inch) with each rotation of roller 40. 05 now) moved. When the ¹ surface peripheral speed of the roller 40 was increased, the amount of movement of the edge 25 remained essentially the same for different surface peripheral speeds of the roller 40. The total deflection of the metering member 10 increased somewhat as the surface peripheral speed of the roller 40 was increased. It was also observed

(3

that - if the pressure on the release cylinder 92 has not been released - the edge 25 to the axis C around moved about 0.20 inch (about 0.51 ram) when the applicator roller 40 was stopped. Accordingly, the polished edge 25 of the metering member 10 moves automatically relative to the axis C of the application roller 40 with each movement of the application roller 40 as a result of changes in speed and out-of-roundness of the applicator roller to allow compression of the roller jacket 44 by the Edges 25, 28b and the support surface 26 of the metering member TO and damage resulting therefrom of the roller jacket 4 4 as well as the resulting streaks on the printed sheets, the system should be designed in such a way that the pressure in cylinder 7 2 is reduced or completely relieved, when the roller 40 is stopped.

At the start, the air pressure should be set back to the normal working pressure against the stop screw 44 will. In this way, the maximum indentation of the edge 25 into the roller surface 45 takes place only when the roller rotates under the edge 2 5 with a film of paint N in between. If the pressure is not reduced when stopping, the edge 24 pushes the roller surface 4 5 almost around the twice the amount as under running conditions.

From Fig. 9 of the drawings it can be seen that the ink film thickness over a wide range of speeds remained essentially constant and that it accordingly remained essentially independent of the surface velocity the applicator roller 40 is.

As already described above, it moves

the edge 25 of the metering member 10 automatically in the radial direction when the applicator roller 40 rotates. The metering member 10 is positioned so that the metering surface 24 and the polished edge 25 are firmly supported in the tangential direction. It can be seen that the force exerted on the metering surface 24, which is generated due to the application of paint, is directed both in the tangential and in the radial direction to the applicator roller 40, and that the force against the surface 22 of the metering member 10 is only substantially is directed tangentially. It should also be pointed out that the metering member 10 is angularly positioned in such a way that it is very stiff in an essentially tangential direction to the applicator roller 40. This means that during operation in a dynamic position the angle A _{3 of} the support surface 26 is essentially 0 or can be somewhat larger. The pressure wedge angle W, which arises directly in front of the edge 25 of the metering member 10 and acts against the roller surface 120 and the metering surface 24 because the surface 24 is only relatively small, cannot generate a sufficiently large force to move the edge 25 from the roller surface 45 or to lift or remove the roller surface 45 from the edge 25 and result in a change in the film thickness as the speed increases.

While it is necessary that the metering member 10 be configured or arranged to have the edge can press in the radial direction, the metering member 10 on the other hand must have a sufficiently large thickness have to have a recess r and a cantilever planer thickness T ./. r to enable, with a bc-

sensitive metering surface 24 and a polished edge The metering member 10 should not be too thin, because if a compressive force is exerted in the plane of a thin plate, then it has a tendency to bulge and to warp or to kink, as this is loaded axially in the same way with a long, thin one Stalk is the case. The color density printed on a sheet was measured using a "SOS 40" digital reflection densitometer measured, from the company COSA Corporation, Garland, Texas / USA, is available. The color density readings in the longitudinal and transverse directions of the printed sheet are with respect to yellow ink in Fig. 10 of the drawing. It can be seen that both the measured Color density in the transverse direction as well as in the longitudinal direction can be described as very precise can. Other inks such as magenta, cyan and black were obtained with equally good results measured.

The data shown schematically in FIG. 10 show that with the metering member TO a very uniform Ink film on the surface 45 of the applicator roller 40 has been dosed.

It was found that the drive power that for driving a printing machine with an inking unit according to the invention as described above is required, is not significantly different from the drive power required to drive a A printing press equipped with conventional inking units is required, and in most of them Cases is lower. As has been explained above, the "ghost image" exploited in terms of color is

- ir «-

on the surface 4 5 of the applicator roller 40, which moves from the plate P ¹ to the input side of the ink reservoir R, completely replenished with fresh new ink and the printing plate P 'is offered a newly dosed ink film with each rotation of the applicator roller 40. In this way, "starvation" of color or the formation of so-called ghost images was eliminated. Furthermore, because of its construction, arrangement and support, the metering member 10 described above and below is capable of metering a film that is sufficiently thin and sufficiently uniform for coloring a printing plate without critical components quickly wearing out, with an in or Multicolor printing of the highest quality is to be practiced. The color density can be changed immediately by simply changing the setting of the stopper screw 74, which is possible by remote control.

With proper training and arrangement, this has the effect Dosing member 10 further that lint or other foreign particles in the color of the between the surface 2 of the metering member 10 and the surface 21 of the applicator roller 40 formed wedge are kept away. The metering surface 24 and the surface 22 form a barrier above the edge 24, against which excess Color strikes on the applicator roller 40 as it were in a surfaced manner, with a turbulent section is formed as described above. As the high pressure section is formed immediately before the paint moves past the polished edge 25, lint and other foreign particles become normally distant from this section

hold if there is a low-pressure path in the paint supply R or section is available. The paint reservoir R is preferably under atmospheric pressure. Also light ones Foreign particles are picked up in the center of the vortex that is formed in this low pressure section.

It should again be pointed out that the creation of the steep, substantially radial surface 22 prevents that hydrokinetic ^ or hydrodynamic forces arise, which a hydraulic pressure wedge can produce, which lifts the polished edge 25 and would accordingly result in the thickness of the color film 130 changes when the surface speed changes the roller 4O changes. The edge 25 is thus carried or supported hydrostatically by paint, which is carried by the roller surface 45.

Any tendency of the metering member 10 to move away from the roller 40 or vice versa becomes rapid and automatically overcome by opposing elastic restoring forces that act against each other when both, i.e. the roller jacket 44 and the metering member 10 are under mutual elastic pretension, like this one is described above.

Various factors influence the ink film thickness that is metered onto the surface 45 of the applicator roller 40. These factors include, but are not limited to: the front angle, the angle A- between the metering surface 24 and the support surface 26; the angle A ₂ between the metering surface 24 and a radial line; the state of the metering edge 25; the width or depth S of the support surface 26; the viscosity of the paint; the harshness of having one

application roller 45 provided with elastic coating 44; the thickness of the shell 44 of the applicator roller 40; and the load or force that is impressed around the metering edge 25 in pressing relative pressure engagement with the jacket 44 of the applicator roller 44 bring.

The rigidity of the working end 10 'of the metering member 10 affects the uniformity. As has already been described above, the metering edge must Be deformable over the length of the application roller 40, so that they are manufacturing inaccuracies of the roller surface 45 and can create a uniformity across the width.

Test results show that the thickness of the ink film 130 responds to the following: (1) an increase in the indentation of the metering edge 25 into the jacket 44 of the applicator roller 40; (2) a reduction in the portion of support surface 26; (3) an increase in the force which presses the metering edge 25 in the direction of the axis C of the applicator roller 40; (4) a reduction in the hardness of the shell 44 of the applicator roll 40; (5) an increase in the radius of curvature of the metering edge 25; (6) an increase in the thickness of the shell of the applicator roll 40; and (7) an increase in the angle A ₂ between the metering surface 24 and a line R which extends radially to the applicator roller 40. The following are also of influence: an increase in the viscosity of the paint contained ^{in the reservoir R 1;} a decrease in the temperature of the paint contained in the reservoir R '; and an increase in the roughness of the surface 45 of the applicator roller 40 also results in an increase in the thickness of the ink film 130.

It can be seen on the basis of the above statements that an adjustment of any of the seven influencing factors mentioned above results in a change in the angle W, as is shown in FIG. 3 of the drawing. It has been found that a setting facility for the indentation of the metering edge 25 and an adjustment for the angle A "by rotating the metering surface 24 to change the metering edge 25, by the angle A, or by incorporation of a dosing member 10 with a different angle A ₁ results in adequate ink film thickness control for the printer. In an experiment in which a printing ink of low viscosity was used and in which a metering member 10 with an angle A .. of 160 and a roller shell hardness of 40 hardness units was provided, the ink film 130 was too thick. The metering member 10 was replaced by a metering member 10 with an angle A- of 150 ° and the color film 130 was immediately extremely satisfactory.

In another experiment, the ink film 130 was too thick for one color for printing on sheets, in which experiment a metering member TO with an angle A- of 130 and a roller jacket hardness of 30 hardness units had been used. This roller was replaced by a roller with a jacket of 60 hardness units and the ink film 130 was then too thin. The metering member with an angle A ₁ of 120 ° was then replaced by a metering member 10, which has an angle A ₁ of 130 °, and the paint film was then extremely satisfactory on the roller 40 with a jacket 44 and a hardness of 60 hardness units.

When a metering member 10 with an angle A ₁ of 90 was tried in cooperation with a roller 40 of a jacket with 60 hardness units, the ink film 130 was much too thin in the printing ink used for lithographic printing on sheets.

The influencing factors listed above, which the The dosing of color must be correlated, i.e. assigned to one another, in order to achieve a thinly dosed color To provide ink film suitable for use on a lithographic printing plate. As below in more detail in connection with various specific examples of the relative Assignment of the working end 10 ′ of the metering member relative to the surface 45 of the application roller 40 is explained, one or more of the influencing factors listed above can be changed to to change or set the color film thickness.

About the working and functioning of the metering member To understand clearly, it is necessary to clearly delimit or define some terms. the Metering surface 24 influences the metering of paint of different viscosities and a change in the angular Relation of the metering surface 24 relative to the surface 45 of the application roller 40 change the Color film thickness. The main reason that the metering surface 24 has a considerable influence on the ink film thickness, consists in the fact that the metering surface 24 intersects the support surface 26 at an apex and not significantly is rounded. The thickness of the color film is determined primarily by the relative allocation of the Dosing surface 24 and the dosing edge 25 relative to

the surface 45 of the applicator roller 40 is determined.

As will be explained in detail below, the support surface 26 influences the thickness of the color film 130 formed on applicator roll 40 not considerable. Experimental results show that within certain limits the angular The relation of the support surface 26 relative to the radial line R does not in itself mean the ink film thickness changes. It also appears that the trailing edge 28b does not (much) affect the film thickness. the However, surface 28a and support surface 26 must intersect or penetrate one another at an apex, so that the metering member 10 is almost abruptly separated from the surface 45 of the roller 40, so that no color accumulates on the surface 28a and leads to the phenomena as detailed above are described.

The angular relationship between the metering surface 24 and the support surface 26 and the orientation of the metering surface 24 and the support surface 26 relative to the surface 45 of the applicator roller 40 are critical. As already described above, a first consideration in the selection of the angle A ₁ between the metering surface 24 and the support surface 26 is the viscosity of the paint to be metered. From Example II it can be seen that a metering member 10 with an angle of 150 between the metering surface 24 and the support surface 26 has been selected to meter printing machine ink, namely an ink with very low viscosity, whose toughness and flow properties are called Designate "water-like"

could. Lithographic printing ink has a higher viscosity than printing ink used in printing presses, and it should be noted that in the example in I and III the angle A ₁ between the metering surface 24 and the support surface 26 was considerably smaller than the angle A ₁ of the metering member, as it has been used for metering printing machine ink.

In the example in I to III, the metering edge 25 was designed to have a highly polished precision surface as described above.

The width S of the support surface 26 in itself controls the thickness of the ink film 130 that is on the applicator roller 40 is formed, not. The width S of the support surface 26 is chosen so that the desired Indentation of the metering edge 25 is realized in the elastic roller surface. if a force of a predetermined magnitude is exerted on the dosing member 10. The force with which the dispensing edge 25 is brought into pressing pressure relation with the surface of the application roller 40, should be sufficient be large in order to ensure an indentation of the metering edge 25 in the elastic roller surface to to allow some movement of the metering edge 25 radially to the roller when the latter rotates, however large enough to create uniformity and uncontrollable or uncontrollable Vibration of the metering member 25 when the Drehon To prevent roller 40. Since the indentation of the metering edge 25 is primarily a function of the pressure

3225382

which is equal to the applied force divided by the size of the support surface is, is specific to the realization Parameter to choose the size of the support surface, which then also the sensitivity for the control the device is to be determined.

The viscosity of the paint can be slightly increased by the addition of chemical thinners or thickeners and by adjusting the temperature. However, there should be certain characteristics of the color not be changed in a disadvantageous manner if a lithographic quality stop is to be achieved.

The hardness of the roller must be adapted to the angle A ~ between the metering surface 24 of the metering member 10 and the roller surface 45 or vice versa in order to create a wedge W in the area between the metering surface 24 and the surface 45 of the applicator roller 40 immediately adjacent thereto and immediately upstream of the metering edge 25 to form a film of the desired thickness. It must be taken into account that one and the same metering member 10 penetrates deeper into a softer roller surface than into a hard one when the same force is exerted on the metering member 10. As FIG. 3 shows, this would reduce the angle W between the metering surface 24 and the surface 45 of the applicator roller 40, ie if the hardness of the surface 45 or of the jacket 44 of the applicator roller 40 is reduced.

The thickness of the jacket 4 4 of the applicator roller 40 influences the dosage, since the spring constant of an elastic roller is not linear when the force

grows. When the roll surface is heavily compressed the flexibility or its deformability decreases. So if the thickness of the jacket 44 of the Application roller 40 is decreased, the apparent increases Hardness of the elastic jacket 44.

As has already been mentioned above in connection with the width S of the support surface 26, the Load or bias of the metering member 10 can be chosen so that it is ensured that the metering edge 25 moves radially as necessary while roller 40 rotates. However, the force must be sufficient be large in order to regularly deform the metering member 10 and the metering edge 25 into the roller 40 in order to establish an angular relation between the metering surface 24 and the surface 45 of the applicator roller 40 adjacent to the metering edge 25 to create that for a uniform metering of a certain Color is necessary.

The angle A ^ between the support surface 26 and a Tangent to the surface 45 of the applicator roller 40 is not particularly relevant and influences in itself taken the dosage hardly or not as long as the rear edge in the elastic surface 45 of the roller 40 remains pressed in, and as long as the force, which the support surface 26 in the pressing relation to the resilient surface 45 of the roller 40 is large enough to prevent hydroplaning. If, however, a very small force, for example 1 ppi of the length of the metering member 10, is applied, in order to press the metering edge 25 into the surface 45 of the roller 40, it is necessary to use the support surface 26 then essentially perpendicular to a plane too

position that extends radially to the elastic surface of the roller 40 to exclude that it is under dynamic conditions during the run can lead to a lifting force, which would have the cause that the color film thickness increases as the speed increases.

The following examples are given to illustrate specific application examples of the invention described herein to show, using different lithographic printing inks with different viscosities have been.

The following values have been constant in the following examples:

L = 1.6 25 inches (approx. 41.3 mm)

1 = 1 inch (approx. 25.4 mm)

A ₃ S o °

t = 0.070 inch (approx. 1.78 mm)

r = 0.035 inch (approx. 0.89 mm)

h = 0.02 inch (approx. 0.51 mm)

t ./. h = 0.05 inch (approx. 1.27 mm) and

t ./. r = 0.035 inch (approx. 0.89 mm).

EXAMPLE I

Lithographic sheet printing ink (offset)

data

colour

paper

plate

Printing blanket

Printing press

speed

Roller width

Angle B

Angle A ..

Angle A ₃

A ¹

Color density
Ink reserve solution strips - FR to the plate plate cylinder diameter

Speed ratio between application roller and Plate cylinder

Process - Magenta & Cyan Mead Offset Enamel - 70% Tri-Metal - Metalgamma Reeves # 714 Compressible Harris LUM - 2 / c 2000 - 6000 IPH 38 "40 ° 130 ° approx. 4O ° 0.150 60 ° 1/2" (Buna N Rubber) 60 Shore A 0.04 "5-1 / 8" 1.20 - 1.40 6O ⁰ F - acid with 25% alcohol 1/2 "- 5/8" 10 "

1: 1

EXAMPLE 2

Printing machine color (litho direct)

colour black paper Newsprint plate Western front page wipe on Printing blanket. N / A Printing press Goss Universal Speed (V) 300-900 FPM Roller width 36 " Angle B 60 ° Angle A ₁ 150 ° Angle A " approx. 60 ° S. 0.090 " A ¹ 90 ° T 3/8 "(urethane) D. 40 Shore A d unknown R. 3-1 / 2 " Color density 1.10 - 1.20 Paint reserve solution 70 ° F - alkaline (no alcohol) Stripes - F.R. to the plate 1/2 " Plate cylinder diameter 13-1 / 2 " Speed ratio

between the application roller and the plate cylinder

1: 1

EXAMPLE 3

Lithographic web offset printing ink (test stand)

data

colour

paper

plate

Printing blanket

Printing press

Speed (V) roller width

Angle B

Angle A ^

Angle A ₂

A ¹

R.
Color density

Paint Reservoir Solution Strips - F.R. to the plate Plate cylinder diameter

Speed ratio between the application roller and the plate cylinder

Process Cyan Ν / Α Ν / Α Ν / Α Ν / Α 100-1200 FPM 18 "45 ° 135 ° approx. 4 0.125 * '90 ° 1/2" (Buna N) 60 Shore A Unknown

Film density adjusted to a value suitable for offset web printing N / A N / A N / A

N / A

If the working end 10 'of the metering member 10 is supported by a cantilever arm, how this continues has been shown and described above to generate an elastic radial force and a non-elastic, Creating fixed tangential force is a uniformity due to a relatively high force and the resulting bending of the metering member 10 to achieve against the roller surface 45. However, a great force penetrates excessively into an elastic roll shell, in particular into a relatively soft shell, if not a sufficiently large support surface 26 is present between the two edges 25, 28b of the metering member 10 is to minimize the pressure and thus the indentation of the roll shell. Harder roll shell are therefore recommended, especially since these are also more durable. The pressure on the first edge of the metering member, i.e. at the metering edge 25, which is caused by the relatively slight deformation of the hard, produced by a durable jacket generally results in a thin, lightly metered film, unless that a certain ineffective pressure wedge due to an obtuse angle at the indented working end 10 ' of the metering member 10 is formed. The extent of the indentation of the hard shell by a relative Slightly indented, blunt edge leads to a long service life of the edge and the roller jacket

From the preceding statements it should be apparent that the paint metering member 10, when it is with a Application roller 40 cooperates, the invention Solves tasks and goals as listed above.

"is

In addition, it goes without saying that the above Embodiments described with reference to the drawings are just examples represent, and that other, further embodiments of the invention are possible without the scope of to leave the present invention.

BSZUGoZKIClIENLIGTS (LIoT OF RSF

1 Inking unit Dosing surface 1 ο Side frame (of 1) Dispensing edge 2 3_ Page frame (of a printing press) Support surface 4th chain Recess 27 'groove (in 44) 4th Support device (for 10) 5 'line (in 5) Top (of 10) 28 'top (of 27) 5 6th Page limits ,.,,. ,,., "\ 28ci dxlLLt; Flcidit; (vuii 10)
Bottom (of 10) _{28b rear edge G {of 26)} 6th 7th flexible pipes - 7th * a _f b Ink reservoir oscillating rollers 8c dye and dampening liquid 8th 1 , ability supply oscillating roller 9 10.ΙΟ Dosierqlied 10 '' dosing part (of 10) 10 Ι 1 - 11th 12th - 12th 15th - 14- - 14- 15th - 15th 16 - 16 -17 - 17th 1 Β - 18th 1? _ 19th 23 20th £ - 1 21 ** Λ 'J front side surface (of 10) 22 'rear side surface 22nd ^: * τ ( from K J)
25th 24 24 25th 25th p. 26th 27 27 23 28 21 29 50 50

CWC r γ.μϊοητ I

31 - 31 7, A - 32 7, /, - ⁷ , 3 3-V - 34 35 - y 36 - 36 37 - 37 33 - 38 39 - 39 40 applicator roller / J-O 41 - 41 i \? Core (of 40) 4.? 43 - ^ 3 44 elastic coat (of 40) 44 45 surface (from 44 or 40) ^ 5 46 - 46 47 - 47 48 - 48 '+9 - 49 50 support beams (of 5) 50 51 pens 51 52 (flat) surface (of 50) 52 ' Anchor bolts 52 ^r ^ 3 - 53 54 area (of 50) 54 55 shoulder 55 56 bearings 56 57 bushings 57 58 protrusions 58 59 - 59 60 storage blocks 60 61 - O 1 62 - 0? r, 3 - 63 64 Lifting Screws 6A 65 area (of 2) 65

co transverse adjustment screws 66 ' End faces 66 67 r- "« approaches (of 2) 68 £ .0 - 69 7 3 arm 70 ^r ~ ', piston rod 71 ~~ cylinder 7? 7 Λ - Ti 7 '+ stop screw 74- 75 arm 75 76 screws 76 '7 ~ 77 73 clamping link 78 : ^; 9 - 79 rO DC motor 80 ^Γ · Ί Support bracket 81 - ^:; "■ Leadership 82 83 ~ · '+ Line 84 · ■; ^: 5 control unit (for 80) 85 . "ö display 86 87 08 - 88 -9 - 89 90 wave 90 31 - 91 • τ2 release cylinder 92 9 ^ projections 93 ? 4 piston rod (of 92) 94- 95 approach 95 Ί6 adjusting screw 96 97 - 97 ^ S adjusting screw 98 99 - 99 100 color retention wall 100

SO

102 lower edge

105 component

106 screws 108 seal 110 stirrer

120 bead (of 44)

130 color film

P plate cylinder

B cloth cylinder; Angle (Fig. 4)

J. impression cylinder; Moment of inertia

W track; angle

R, R ¹ color supply; Roll radius

D dampening system

P ¹ pressure plate

N gap

A ₁ angle (between 24 and 26)

E modulus of elasticity

A ¹ angle (2.6 / 28a)

C axis (from 40)

R ¹ 'pressure regulator

P ¹ 'intersection 25/45

S, S ¹ support width

A ^ angle

A "angle

viscosity

P ,, pressure maximum M

γ recess

Si

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Claims (4)

1 . _ ί CLAIMS 1. Inking unit for a lithographic printing machine, with an application roller that can be driven by means of a drive and has an elastic surface that rests against a printing plate under pressure, a strip-shaped color Dosierglj ed, and a support means for supporting the dosing member, which is designed in the manner of a cantilever arm, which does not supported end is pressed into the elastic surface of the applicator roller, whereby when the applicator roller rotates an excess of paint is moved ^{to the non-supported end of the cantilever arm, characterized in that at the non-supported end (10 1) of the dosing member (10} ) a metering section (IQ ¹¹ ) is present which has a metering surface (24), a support surface (26) and a rear third surface (28a), the metering surface (24) and the support surface (26) at an obtuse angle ( A ₁ ) stand in relation to one another and intersect or enforce one another at an apex to form a metering edge (25), and wherein the rear third surface (28a) and the support surface (26) intersect or penetrate one another to form a rear edge (28b) at an apex; that the support means (50) positions the support surface (26) of the metering member (10) essentially parallel to a tangent to the elastic surface (45) of the applicator roller (40), through the line of contact between the Dosiergliod (10) and the elastic surface (4 5) of the application roller (40) runs, the metering body of the metering member (1O) at an angle of less than 30 is arranged to the tangent, the rear third surface (28a) is arranged so that the angle between the tangent and the rear third surface (28a) is greater than 30 °, and the Dosing surface (26) is arranged so that the angle between the tangent and the dosing surface (24) is less than 90; and that the metering member (10) and the surface (45) of the applicator roller (40) so are arranged that by the movement of the applicator roller (40) an excess amount of paint against the the dosing surface (24) of the dosing member (10) located at the non-supported end of the cantilever arm is moved, . And the color (of the metered paint film (130)) on the rear edge (28b) of the metering member (10) of this separates. 2. Inking unit according to claim 1, characterized in that the metering member (10) in a known manner made of metal. 3. Inking unit for a lithographic printing plate with an application roller which can be driven by means of a drive and has an elastic surface, which under pressure the pressure plate rests and a metering member, characterized in that the metering member (10, 10 ') a Dosing surface (24), a support surface (26) and a rear third surface (28a) which are mutually enforce and an obtuse-angled dispensing edge (25) and a rear edge (28b) form; that the applicator roller (40) is rotated so that on her Surface (4 5) located paint is moved against the metering surface (24) of the metering member (10, 10 '); that means are provided by means of which the support surface (26) substantially tangential to the surface (45) of the applicator roller (40) and in engagement is to be positioned with this, so that the angle between the metering surface (24) and a radial to the roller (40) extending line in the range between 10 and 70 °, the metering surface (24) to the radial Line is employed in the direction of the approaching roller surface, and the metering edge (25) is formed is to ensure that when changing the angle between the metering surface (24) and the radial Line a change in the thickness of the paint film (130) adjacent to the metering edge (25) on the surface (45) the application roller takes place; and that means are provided by means of which the metering edge (25) and the trailing edge (28b) in relative pressure engagement with the resilient surface (45) of the applicator roller (40) are to be brought. 4. Device for dosing a liquid and for controlling a specific, thin, even liquid film given viscosity from a supply of an excess amount of liquid to a liquid carrier, characterized by an endless, rotatable, liquid-carrying component (40) with a smooth, firm, resilient outer surface (45) that is textured and capable of a continuous To wear liquid film (130); an elongated metering member (10, 10 ') with essentially trapezoidal cross-section, which is flexible along its length, the trapezoidal shape by two im substantially parallel surfaces, namely an upper surface and a lower surface, is formed, and one surface forming a top surface and the other a smooth, hard support surface (26), and further a smooth, hard metering surface (24) and a smooth, hard rear surface (28b) are present with the support surface (26) intersecting the metering surface (24) and the rear surface (28b) and forms two smooth, hard edges (25, 28b) over the entire length of the support surface (26), wherein the metering surface (24) forms an obtuse angle with the support surface (26), so that a hard, durable, polished, obtuse-angled edge on the flat Enforcement is formed; that the endless, rotatable, liquid-carrying member (40) from the support surface (26) is pressed in, and that both edges (25, 28b) of the elongated, flexible metering part (1O, 10 ') accordingly are pressed in over the length of the metering part, the metering surface (24) of the metering part (10, 10 ') forms a barrier or weir for an excess liquid supply, which is caused by the textured, elastic outside (45) of the liquid-carrying part (40) is supported and wherein the obtuse angle of the dosing part elastically yielding over its length against the elastic surface (45) of the liquid-carrying Component is pressed, and wherein the trapezoidal section continues in a surface parallel to the support surface (45) is firmly supported against a restoring force originating from the elastic surface (4 5), the one against the obtuse-angled edge (25) and which acts against the support surface (26) of the metering member (10, 10 '); that means of turning the endless Support surface (45) relative to the metering member (10, 10 ') are present so that the liquid against the surface of the barrier strikes as well as the obtuse-angled metering edge (25) of the metering member (10, 10 '); that a thin, essentially uninterrupted, continuous film of liquid (130) is sheared off and dosed on the surface and of this uniformly from the rear surface (28a) and the rear edge (28b) of the metering member (10, 10 ') from the textured surface (45) of the jacket of the support member (40) is carried away; that the elastic force acting on the flexible, elongated support surface (26) of the Dosing member (10, 10 ') acts, is sufficiently large to the elastic jacket or the elastic Surface (45) of the support part (40) to be pressed elastically along the edges (25, 28b) of the metering member (10, 10 ') to create a substantially uninterrupted continuous liquid film (130), which is essentially constant over the length of the metering member (10, 10 ') and the path of the metered film is how it emerges at the rear edge (28b) of the metering member (10, 10 '); and that of the liquid mass at the inlet of the metering surface (24) of the metering member (10, 10 ') or the surface (45) of the elastic outer side (45) of the support part (40) adjacent to the obtuse-angled Dosing edge (25) of the dosing member (10, 10 ') and the obtuse angularity of the dosing edge are preselected and are sufficiently large to dose the liquid, which has given flow properties, to one To dose film (130) with the desired thickness without considerable indentation and accordingly avoiding rapid wear and tear or rapid destruction of the metering member (10, 10 ') or the support surface (45).