Screen printing device and screen printing method for producing three-dimensional screen prints

Abstract

A screen printing device for producing a three-dimensional screen print comprises one or more screen printing cylinders. The screen printing device is configured so as to successively apply M printing layers onto a printing substrate, where M is greater than or equal to 2. For each m from 1 to M, the screen printing device is configured so as to bring about a relative movement between the printing substrate and a screen printing cylinder for applying the m-th printing layer and, at the same time, a rotation of the screen printing cylinder about its cylinder axis such that the screen printing cylinder rolls on the printing substrate and thereby applies the m-th printing layer onto the printing substrate. For each m which is greater than 1, the distance, during the application of the m-th printing layer, between the printing substrate and the screen printing cylinder for applying the m-th printing layer is greater, by the thickness of the (m-1)-th printing layer, than the distance, during the application of the (m-1)-th printing layer, between the printing substrate and the screen printing cylinder for applying the (m-1)-th printing layer.

Description

[0001] T33015W0

[0002] TERRAMARK Markencreation GmbH

[0003] Screen printing device and screen printing process for producing three-dimensional screen prints

[0004] Description

[0005] The present invention relates to a screen printing device and a screen printing method for producing three-dimensional screen prints.

[0006] A well-known method for producing three-dimensional screen prints is D-flatbed screen printing, as described in DE 42 05 969 C2. A corresponding device for producing three-dimensional screen prints is described in EP 2999595 A2. In this technique, a flat screen with a layout is used, through which the substrate or "ink" is transferred to a substrate positioned below by means of a squeegee. While the screen and substrate are stationary, a squeegee is moved across the screen, thereby transferring the layout, along with the substrate, to a substrate below. After each printing process, the distance between the screen and the substrate is increased by the thickness of the previously applied print, so that the next print is carried out under the same conditions. By changing the screen, different structures and materials can be realized in a single component.

[0007] However, this method is reaching its limits today, primarily due to the dynamic variables and influences of screen technology, stretching, warpage, time-related changes in screen tension, and also difficult-to-control doctor blade and squeegee conditions, such as the changing position of the squeegee and squeegee rollers of the applied material during each printing process. Even if the dimensional deviations in successive printing layers of the body are only slight, they can accumulate considerably during the print build-up. Furthermore, long changeover times and downtimes lead to a high degree of inflexibility in the body structure.

[0008] It is an object of the present invention to provide a device and a method for producing a three-dimensional screen print in order to improve user-friendliness with regard to the desired applications.

[0009] The above problem is solved by a screen printing device according to claim 1 and a screen printing method according to claim 17. Claims 2 to 16 relate to particularly advantageous embodiments of the screen printing device according to claim 1. The present invention relates to a screen printing device for producing a three-dimensional screen print, which comprises one or more screen printing cylinders (or screen cylinders or screen cylinder rollers or stencil rollers or printing units). The screen printing device is configured to successively apply M printing layers or print levels to a printing substrate or substrate or a print receptacle, where M (a natural number) is greater than or equal to 2. The three-dimensional screen print can be a geometrically structured body and can comprise or consist of the M printing layers.For each m from i to M, the screen printing device is configured to cause a relative movement between the substrate and a screen printing cylinder (from one or more screen printing cylinders) to apply an m-th printing layer (of the M printing layers), and simultaneously a rotation of the screen printing cylinder about its cylinder axis, so that the screen printing cylinder rolls or unwinds on the substrate or a surface of the substrate (or on the m-th printing layer or a surface of the m-th printing layer), thereby applying the m-th printing layer to the substrate or the surface of the substrate (or on the m-th printing layer or the surface of the m-th printing layer). In this way, a first printing layer (m = i) can be applied to the substrate, then a second printing layer (m = 2), and so on, until finally an m-th printing layer is applied to the substrate.

[0010] The one or more screen printing cylinders can each comprise a drum screen (or sleeve screen, stencil roller, or screen drum), in particular a screen in the form of a hollow cylinder, as well as a layout carrier (or a layout carrier drum) that is applied to the drum screen. The layout carrier can also have the form of a hollow cylinder and can, according to a desired print image or layout, have one or more printing areas (openings, perforations) that are permeable to a substrate, printing material, or printing compound, and / or one or more blocking areas that are impermeable to the substrate. The layout carrier can thus form a stencil by means of which the desired layout can be transferred to the substrate.

[0011] Furthermore, the screen printing device can include one or more feed units, each for feeding a substrate into an interior of a respective screen printing cylinder. The screen printing device can also include one or more squeegees, each arranged in an interior of a corresponding screen printing cylinder, for pressing the substrate through the drum screen or the printing areas of the layout cylinder onto the substrate. The one or more squeegees can each be arranged to be stationary relative to a cylinder axis of a corresponding screen printing cylinder. During the relative movement between the screen printing cylinder and the substrate, the squeegee arranged in the screen printing cylinder is thus moved relative to the substrate; however, the squeegee does not rotate with the screen printing cylinder, but always points towards the substrate to press the substrate from the screen printing cylinder onto the substrate.The one or more screen printing cylinders can include the one or more feed units and / or the one or more squeegees.

[0012] During the relative movement (feed motion) between the printing medium and the screen printing cylinder, the cylinder axis of the screen printing cylinder can be fixed relative to the housing of the screen printing device, while the printing medium moves relative to the housing. Alternatively, the printing medium can be fixed relative to the housing, while the screen printing cylinder moves relative to the housing. The relative movement between the printing medium and the screen printing cylinder and the rotation of the screen printing cylinder about its cylinder axis can be synchronous, such that the speed of the relative movement is equal to the linear velocity of a point on the circumferential surface of the rotating screen printing cylinder. When the screen printing cylinder rolls on the printing medium, the cylinder axis can run parallel to the surface of the printing medium, and the distance between the cylinder axis and the printing medium can be constant.

[0013] The relative movement between the printing substrate and the screen printing cylinder, as well as the rotation of the screen printing cylinder about its cylinder axis, can be effected by separate or combined electrical, mechanical, magnetic, pneumatic, and / or hydraulic drive units of the screen printing device. Alternatively, the rotation of the screen printing cylinder, which is effected, for example, by a drive unit, can cause the relative movement, e.g., by means of static friction between the screen printing cylinder and the printing substrate, or conversely, the relative movement can cause the rotation of the screen printing cylinder, e.g., by means of static friction.

[0014] The feed can therefore preferably be generated via the printing unit or the screen printing cylinder, which drives the printing medium (or the receiving unit into which the printing medium is inserted, as described below). Alternatively, a counter-pressure-generating component, if used, can also generate the feed. This makes it possible to perform the synchronous movements with only one drive unit, which represents the minimum requirement (apart from the feeding and removal of the printing medium).

[0015] The printing substrate can be plate-shaped and, in particular, designed as a rigid plate. A printing layer or layer can be applied to the printing substrate by pressing the substrate against the screen printing cylinder or the screen printing cylinder against the substrate during the relative movement between the printing substrate and the screen printing cylinder and the simultaneous rotation of the screen printing cylinder about its cylinder axis. In particular, the printing substrate itself can be driven synchronously with the screen printing cylinder and thereby generate the counter-pressure required for printing even during its movement. Alternatively, a receiving device in the form of a printing carriage driven synchronously with the screen printing cylinder, as described below, can receive the printing substrate and guide it under the screen printing cylinder, pressing the printing substrate against the screen printing cylinder.Alternatively or additionally, pressure can be generated by a counter roller or pressure roller, or by gravity or another force acting between the substrate and the screen printing cylinder. This pressure creates a contact strip or contact area between the substrate and the screen printing cylinder or the layout carrier, and the material is pressed from the interior of the screen printing cylinder, through the drum screen and the printing areas of the layout carrier, onto the substrate or contact area by means of the squeegee. As the screen printing cylinder simultaneously rolls along the substrate, as described above, the layout of the layout carrier is transferred to the substrate by means of the material being printed.

[0016] For each m that is greater than i (i.e. for each m from 2 to M), a distance (drop, screen printing form distance) during the application of the m-th printing layer, between the substrate or the surface or top edge of the substrate and the screen printing cylinder for applying the m-th printing layer, or a lateral surface or cylinder axis of the screen printing cylinder for applying the m-th printing layer, is greater than or substantially greater than a thickness (print job thickness or print job height) of the (mi)-th printing layer.

[0017] The one or more printing layers can have identical or different thicknesses. This can be achieved, in particular, by using screens with identical or different thicknesses. Furthermore, the one or more screen printing cylinders for applying multiple (especially successive) printing layers can be identical or different. In particular, the one or more screen printing cylinders can have identical or different layout carriers for printing identical or different layouts. Furthermore, the one or more screen printing cylinders can contain identical or different printing material. Between the application of two (especially successive) printing layers, the layout carrier of a screen printing cylinder can be replaced to change the layout, and / or the printing material inside the screen printing cylinder can be replaced or re-fed.Multiple screen printing cylinders with varying distances to the substrate can be used to apply multiple layers of print without having to change the layout carrier or the substrate between layers. Different layouts and / or materials can be applied either by a changeover during layout and / or material changes at a single printing unit, or by subsequent printing units in a line. If multiple printing units are used, they can be synchronized in drive and position, especially with a consistent print carriage as described below, and mutual registration of the screen cylinders. The number of prints per print job can be not only the same but also different. For example, a first cylinder can print twice, and a second cylinder only once. Other combinations of cycle sequences are also possible.

[0018] The screen printing device according to the invention has the advantage that, due to the rolling of the screen printing cylinder on the substrate during the application of each printing layer—i.e., due to the synchronized feed of the substrate with the screen printing cylinder—a shear load against the printing direction is eliminated or reduced. The closed cylinder screen circumference reduces the screen distortion in the squeegee direction, which is detrimental in D-flatbed screen printing, to such an extent that the frictional resistance between the squeegee and the screen wall, which is also present, is constant over the entire squeegee stroke during the printing of a single layer of material. Thus, the printing thickness remains homogeneous throughout the entire print, also because separate flooding is not necessary. Consequently, an accumulating printing height error can no longer occur.

[0019] Furthermore, the screen printing device according to the invention allows the printing carrier to be continuously guided under the screen printing cylinder, enabling a uniform and precise transfer of the printing material. Additionally, the use of a screen printing cylinder in which the screen and layout carrier are clamped in a cylindrical shape creates linear contact between the screen printing cylinder and the printing carrier parallel to the cylinder axis, along which the printing material is released as the screen printing cylinder rolls. The contact remains constant and linear except for the displacement along the rolling direction, resulting in higher print quality. The force required to release the printing material can also be generated by the cylinder's screen circumference without the need to deflect the screen mesh as in D-flatbed screen printing. Moreover, the rotation of the screen printing cylinder can be controlled very precisely, e.g.,The use of servo motors increases the accuracy of the printing process. Furthermore, a high printing speed can be achieved through a high rotational speed of the screen printing cylinder. Thus, the screen printing device according to the invention can produce more precise screen prints than, for example, D-flatbed screen printing. If layout misalignments in the printed component lead to, for example, flow losses or turbulence in heat exchangers, reactors, mixers, and other components, the component walls perpendicular to the printing direction must have a high degree of smoothness.In the D-flatbed printing process, even with smaller screen dimensions, screen elongation, the high proportion of printing material on the screen during printing—the weight of which causes the screen to sag with corresponding layout elongation, and, especially during the printing start-up phase, shifts in the printing point—lead to manufacturing tolerances of several hundred millimeters, not only in the vertical z-axis, but also in the horizontal x- and y-axis, and additionally in the print build-up height, combined with material overhangs and a wavy surface. These product parameters can be reduced to just a few millimeters by the screen printing device according to the invention. This is particularly advantageous in the manufacture and use of bipolar plates, flow fields, and products that have flow-optimized requirements or interact with other components, as is the case, for example, with mechanical seals.

[0020] Furthermore, the screen printing device according to the invention enables a higher application thickness and dimensional stability of the printed layers, making it particularly suitable for producing identifiable and tactilely perceptible raised areas. In addition, the stability of the screen printing device is increased, and the fixation of the printing substrate can be simplified; for example, a 3-point contact position of the printing substrate can already generate the desired positional stability without additional fixation. Damage to the screen print or the screen printing device can thus be avoided.

[0021] By ensuring that for every m greater than 1, the distance between the printing substrate and the screen printing cylinder for applying the m-th printing layer is greater by the thickness of the (mi)-th printing layer than the distance between the printing substrate and the screen printing cylinder for applying the (mi)-th printing layer, it can be ensured in particular that the pressure between the screen printing cylinder and the printing substrate, and thus the squeegee pressure, which corresponds to a stripping of the printed material, remains the same when applying each printing layer, and thus the multiple printing layers are applied with consistent quality and accuracy.Furthermore, by using multiple screen printing cylinders with identical or different layout carriers and with identical or different printing material, the flexibility, efficiency and speed of the production of three-dimensional screen prints can be increased.

[0022] Furthermore, positioning and repositioning systems available for conventional rotary screen printing can be applied to this screen printing device. When feeding back a carrier plate, printed once or multiple times and containing the 3D body that builds up with each print, mechanical positioning devices such as registration pins, trapezoidal guides, and grippers can be used, depending on the required precision. Compared to the 3D flatbed printing process, the problem of the material becoming trapped in the screen mesh is prevented or reduced. Partial release or smearing of the layout edges does not occur, resulting in significantly smoother walls on the screen-printed body. The close contact between the screen and the print body also reduces or prevents smearing of the printed layers against each other. This is particularly important when, for example,A second type of material is to be printed not only across the entire surface, but also partially. The possibility of through-hole plating is also applicable here in tablet manufacturing with or without gradients across the tablet height and its edges.

[0023] Furthermore, examining the mass in the printing cylinder with the squeegee stationary reveals a consistently stable amount of material throughout the printing process, even when the squeegee reaches a holding position within the cylinder screen. These constant conditions eliminate the dynamic problems associated with using a traditional screen printing frame.

[0024] Plastic or metal mesh, or stencils, can be used for the core screens of screen printing cylinders. If the material compatibility between the substrate and the mesh exists, metallic meshes are preferable, primarily due to the even higher achievable precision. As with the flatbed process, all possible hardening and stabilization processes can be applied to the individual printed layers.

[0025] In summary, the screen printing device according to the invention overcomes the disadvantages of conventional 3D flatbed screen printing and expands and perfects the applicability of body production using the printing process, thus increasing user-friendliness.

[0026] In a preferred embodiment, the screen printing device is designed for at least one m x between 1 and M and at least one m2 between 1 and M, where m2 is greater than m xis configured such that, after the application of the nu-th print layer to the substrate using a screen printing cylinder (from one or more screen printing cylinders), it increases the distance between the substrate and the screen printing cylinder by a sum of the thicknesses of the rm-th to (m2-i)-th print layers, in order to apply the m2-th print layer to the substrate using the screen printing cylinder. The screen printing cylinder can be the screen printing cylinder for applying the nu-th print layer and the screen printing cylinder for applying the m2-th print layer.Thus, the screen printing device can use the same screen printing cylinder to apply the nub-th and m2-th printing layers to the substrate; optionally, however, the layout carrier of the screen printing cylinder can be exchanged between applying the nub-th printing layer and applying the m2-th printing layer, so that the layout of the m2-th printing layer is different from the layout of the nm-th printing layer; furthermore, the substrate of the nub-th printing layer can be the same or different from the substrate of the m2-th printing layer. Preferably, m2 = m. x + 1, so that two successive printing layers are applied using the same screen printing cylinder.

[0027] Particularly preferred is the screen printing device configured for each m greater than or equal to 2 such that, after applying the (m)th printing layer to the substrate using a screen printing cylinder, it increases the distance between the substrate and the screen printing cylinder by the thickness of the (m)th printing layer in order to apply the m-th printing layer to the substrate using the screen printing cylinder. Thus, the screen printing device can apply each of the M printing layers using the same screen printing cylinder. In other words, in this case, the screen printing device is configured to increase the distance between the substrate and the screen printing cylinder by the thickness of the most recently applied printing layer after each applied printing layer. However, even in this case, the layout carrier of the screen printing cylinder and / or the substrate can be changed between the application of two printing layers.

[0028] Alternatively, the screen printing device can alternately or periodically use two or more different screen printing cylinders to produce a three-dimensional screen print with alternating or periodically changing print layers.

[0029] When increasing the distance between the printing medium and a screen printing cylinder, either the screen printing cylinder can be fixed relative to the housing of the screen printing device and the printing medium can be moved (lowered) relative to the housing, or the printing medium can be fixed relative to the housing and the screen printing cylinder can be moved (raised) relative to the housing. Here, "lowering" can refer to moving "downwards," i.e., towards a support surface of the screen printing device or in the direction of gravity when the screen printing device is in an operating state, while "raising" refers to moving "upwards," i.e., in the opposite direction.

[0030] Thus, in addition to the one-time adjustment of the printing pressure between the screen cylinder and the squeegee, the height can be adjusted after each individual print job on a single substrate, or after several substrates, by increasing the distance between the printing cylinder and the top edge of the substrate by the print job height after each print job. This can be achieved by adjusting the height within the printing unit itself; that is, the screen printing cylinder with the squeegee is adjusted in height, or the substrate or the mounting unit with the inserted substrate is lowered according to the print job height.

[0031] This has the advantage that a separate screen printing cylinder is not required for each printing layer. Instead, the screen printing machine can use the same screen printing cylinder to apply several (consecutive) or all printing layers to the substrate. This is particularly advantageous when multiple printing layers have the same layout or are produced using the same substrate, as the same screen printing cylinder can then be used to apply these layers without changing the layout carrier or the substrate. This increases the efficiency of the screen printing machine and reduces the costs associated with providing multiple screen printing cylinders.

[0032] In a preferred embodiment, the screen printing device further comprises a receiving unit, in particular a printing carriage or an autonomous shuttle, for inserting the printing carrier into the receiving unit and preferably for releasably attaching the printing carrier to the receiving unit as well as for removing the printing carrier from the receiving unit. For each m from i to M, the screen printing device is configured such that it effects a relative movement between the receiving unit, into which the printing carrier is inserted, and the screen printing cylinder for applying the m-th printing layer and simultaneously a rotation of the screen printing cylinder about its cylinder axis to apply the m-th printing layer to the printing carrier.In this case, during the relative movement between the receiving unit and the screen printing cylinder, the cylinder axis of the screen printing cylinder is preferably arranged immovably relative to the housing of the screen printing device, and the receiving unit is moved relative to the housing.

[0033] The holding unit enables precise positioning and movement of the printing medium relative to the one or more screen printing cylinders. Furthermore, when multiple printing media are used, as described below, each media can be inserted into the same holding unit and positioned and moved relative to the one or more screen printing cylinders by means of the holding unit, thus eliminating the need for a separate positioning or drive unit for each media. In addition, the holding unit can be used to press the printing medium, or each of the multiple media, against the respective screen printing cylinder during the application of the printing layers.

[0034] In a particularly preferred embodiment, for at least one m t between 1 and M and at least one m2 between 1 and M, where m2 is greater than m xThe screen printing device is configured such that, after the application of the middle printing layer to the printing substrate by means of a screen printing cylinder, it increases the distance between the receiving unit and the screen printing cylinder by a sum of the thicknesses of the middle to (m2-i)th printing layers in order to apply the m2-th printing layer to the printing substrate by means of the screen printing cylinder, wherein preferably m2 = m t+ i is. In particular, for each m greater than or equal to 2, the screen printing device can be configured such that, after applying the (m-1)th printing layer to the substrate using a screen printing cylinder, it increases the distance between the receiving unit and the screen printing cylinder by the thickness of the (mi)th printing layer in order to apply the m-th printing layer to the substrate using the screen printing cylinder. In these cases, when increasing the distance between the receiving unit and the screen printing cylinder, the screen printing cylinder is preferably arranged to be stationary relative to the housing of the screen printing device, and the receiving unit is moved (lowered) relative to the housing.

[0035] Thus, the holding unit can be used not only for the relative movement between the printing medium and the screen printing cylinder, and for pressing the printing medium against the screen printing cylinder when applying a layer of print, but also for increasing the distance between the printing medium and the screen printing cylinder after the layer has been applied. The holding unit enables particularly precise adjustment of the distance between the printing medium and the screen printing cylinder. Furthermore, if multiple printing media are used, as described below, each of the media can be inserted into the holding unit and positioned relative to the one or more screen printing cylinders using the holding unit, so that a separate positioning unit is not required for each printing medium.

[0036] In a preferred embodiment, the screen printing unit comprises L screen prints, in particular L identical or substantially identical print copies, where L (a natural number) is greater than or equal to 1. For each m from 1 to M, the screen printing unit is configured such that the screen printing cylinder rotates 360° around its cylinder axis L times as it rolls on the substrate to apply the m-th printed layer. In other words, the screen printing cylinder rolls completely L times on the substrate during the application of the m-th printed layer.

[0037] In particular, a limited number L of rotations greater than 1 can be performed at a distance height whose development corresponds to the length of the printhead before the printhead is fed again at a distance between the screen cylinder and the printhead that has been changed by the print build-up height. Furthermore, a parking or waiting position can be integrated into the layout of the screen printing cylinder. This position is suitable not only for positioning the screen cylinder and counter-pressure unit, but also for feeding new printing material without any of it running into the layout being printed.

[0038] This has the advantage that the L print copies can be printed efficiently and at high speed. Furthermore, the continuous movement of the printing medium relative to the screen printing cylinder ensures a uniform and precise transfer of the printed material.

[0039] In a preferred embodiment, the relative movement between the printing carrier and the screen printing cylinder is a linear or substantially linear movement, or a movement along a curved path (sheet guidance), wherein the curved path can in particular be a circle or an ellipse, or a segment of a circle or an ellipse, or substantially such a path. The distance between the printing carrier, or the surface or the upper edge of the printing carrier, and the screen printing cylinder, or a lateral surface or a cylinder axis of the screen printing cylinder, can remain constant during the relative movement, in particular at the level of the respective squeegee.

[0040] In particular, the printing substrate (or the surface of the printing substrate) and / or the M printing layers (or their surfaces) can be curved, in particular simply curved (i.e. curved only in one direction and flat in the perpendicular direction, which runs parallel to the cylinder axis of the screen printing cylinder during the relative movement), in particular as lateral surfaces of a cylinder with a circular or elliptical base or as segments or sections of such lateral surfaces.

[0041] This increases the flexibility of arranging the one or more screen printing cylinders relative to the housing of the screen printing device, as well as their relative movement to each other, and the flexibility of the relative movement of the printing carrier to the one or more screen printing cylinders. In particular, this allows the shape and dimensions of the screen printing device to be adapted to the specific application. For example, in high-performance cooling elements for hot gas turbines or similar applications, the interfaces with the turbine wall play a significant role in the required temperature transfer and the associated thermo-physical expansion. To achieve these contact surfaces without mechanical deformation of the components, which would lead to inhomogeneous structural properties, the printing substrate or carrier can be adapted to the radius of curvature of the turbine wall and thus guided along the screen contact line, always parallel but in a corresponding arc.This results in a component shape from three-dimensional screen printing that already exhibits homogeneous thermal and physical properties in all component directions x, y, and z, thus providing high thermal and physical stability at the turbine wall interface. Product examples include impact heat sinks as well as media supply and discharge systems.

[0042] As another example, sealing systems in the propellant gas guides of jet engines with high leakage rates present a persistent problem in the prior art. The joints of the seals, in particular, are subject to this problem. Due to their large dimensions of up to several meters, one-piece manufacturing is hardly possible or economically feasible. Here, the screen printing device according to the invention offers the possibility of continuously and seamlessly printing a self-contained seal layout in a disc-shaped printing plate without increasing the size of the printing system. This is achieved by repeatedly directing the print under the printing station, where it can be applied to the contact line. The height adjustment, which occurs with each revolution, is carried out inline.

[0043] In a preferred embodiment, for at least one m greater than 1, the screen printing device is configured such that the screen printing cylinder for applying the (mi)th printing layer rolls along a (mi)th rolling direction on the printing substrate, wherein the (mi)th rolling direction can be parallel to the surface of the printing substrate and / or perpendicular to the cylinder axis of the screen printing cylinder for applying the (mi)th printing layer, and the screen printing cylinder for applying the m-th printing layer rolls along an m-th rolling direction on the printing substrate, wherein the m-th rolling direction can be parallel to the surface of the printing substrate and / or perpendicular to the cylinder axis of the screen printing cylinder for applying the m-th printing layer. In a first particularly preferred embodiment, the (mi)th rolling direction and the m-rolling direction are identical. In this case, the printing substrate orThe receiving unit or screen printing cylinder returns to its starting position after the application of the (mi)th printing layer without applying a further printing layer, and then the m-th printing layer is applied by rolling in the same direction as the (mi)th printing layer. In a second particularly preferred embodiment, the (mi)th rolling direction and the m-th rolling direction differ by 180°. In this case, a printing layer can be applied to the printing substrate during each forward and backward movement of the printing unit or screen printing cylinder. In a third particularly preferred embodiment, the (mi)th rolling direction and the m-rolling direction differ by an angle other than 0° and other than 180°, preferably being 90° or 270°. In this case, the printing substrate orThe receiving unit or the screen printing cylinder is rotated between the application of several printing layers around an axis perpendicular to the surface of the printing substrate or perpendicular to the cylinder axis.

[0044] In particular, this means that for 3D printing or for each layer of 3D printing, the print carrier or print carriage can be loaded from all directions and, after printing, can also be removed in all directions.

[0045] This has the advantage that the rolling direction for each printing layer can be optimally adapted to the structure of the printing layer to be applied or the printing layers already applied, thus increasing the flexibility in the construction of the three-dimensional screen printing.

[0046] In a preferred embodiment, the one or more screen printing cylinders are provided with one or more rotary seals, preferably one or more mechanical seals.

[0047] This is particularly advantageous when printing on materials containing or made of oxidation-sensitive substances (printing material) such as the finest metal powders, e.g., copper, aluminum, iron, magnesium, titanium, etc., because the one or more screen printing cylinders, or the printing material arranged within them, can be shielded from external influences—especially oxygen or moisture—by the rotary seals, particularly the mechanical seals. This further increases flexibility in the selection of printing materials and thus user-friendliness.

[0048] In a preferred embodiment, the screen printing device is configured to flood one or more interior spaces of the one or more screen printing cylinders with a protective gas such as argon or nitrogen or a reaction gas such as forming gas, particularly when the one or more screen printing cylinders are at rest and / or during the printing movement.

[0049] This is particularly advantageous when printing objects made of or containing oxidation-sensitive materials (printing material) as described above, since it prevents exposed metal particle surfaces from reacting with the printing mass. A gas pressure within the one or more internal chambers is particularly preferred, as is a higher gas pressure outside the one or more screen printing cylinders; that is, there is a gas overpressure within the one or more screen printing cylinders, especially when stationary. This has the advantage of generating a gas flow from inside the one or more screen printing cylinders to the outside, particularly through the mesh of the respective screen, which minimizes or prevents oxidation of residue adhering to the screen printing cylinder or the screen between prints.

[0050] Alternatively or in addition to the protective gas or reaction gas as described above, a sterile gas can be used to flood the one or more interior spaces.

[0051] This is particularly advantageous when using organic materials, especially carrier materials for inoculation with biological cells, or biological cells themselves, as printing material, since this minimizes or avoids contamination.

[0052] In a preferred embodiment, the screen printing device is configured to flood one or more interior spaces of the one or more screen printing cylinders with a carrier gas or purge gas, wherein the temperature of the carrier gas is higher or lower than the ambient temperature of the screen printing device. Alternatively or additionally, the screen printing device can include one or more heating elements for heating and / or one or more cooling elements for cooling the one or more interior spaces, wherein preferably the one or more heating elements and / or the one or more cooling elements are arranged at least partially or completely within the one or more screen printing cylinders.

[0053] This is particularly advantageous when using temperature-sensitive printing materials such as cells, especially biological and / or vital cells, as it ensures an idealized climate option or an optimal temperature of the printing material.

[0054] In a preferred embodiment, the screen printing device comprises one or more heating elements for heating the one or more screen printing cylinders or one or more core screens of the one or more screen printing cylinders, wherein preferably the one or more heating elements are configured such that they each conduct an electric current through the one or more screen printing cylinders or the one or more core screens, or apply an electric current to the one or more screen printing cylinders or the one or more core screens. The electric current can cause the one or more screen printing cylinders or the one or more core screens to heat up due to their respective electrical resistance.Alternatively or additionally, the screen printing device can be configured to flood one or more chambers of the one or more screen printing cylinders with a carrier gas, the temperature of which is higher than the ambient temperature of the screen printing device. Alternatively or additionally, the screen printing device can include one or more heating elements for heating the one or more chambers. The heat can also be transferred from the one or more chambers to the one or more core screens, or vice versa.Particularly preferably, the one or more heating elements are further configured to heat one or more squeegees, or the screen printing device comprises one or more additional heating elements for heating the one or more squeegees arranged within the one or more screen printing cylinders, as described above, wherein the one or more squeegees are preferably made of metal. The one or more squeegees can heat themselves actively, or this can be achieved by integrated and controlled heating cartridges without the one or more squeegees heating themselves. The heat can then be transferred from the one or more internal chambers and / or sleeve screens and / or squeegees to the respective substrate.

[0055] This is particularly advantageous when using thermally liquefiable printing compounds, similar to the enamels used in glass decoration. During the application of the printing layers by the one or more screen printing cylinders, the printing compound can be at least partially or completely liquefied, especially to facilitate easier and more precise application to the substrate. As the printing compound subsequently cools and hardens, the stability of the printing layers is ensured, allowing for efficient and precise production of the finished product.

[0056] In particular, materials can be used that become stable upon slight cooling. Since the contact time between the cylinder screen and the substrate is very short, the natural cooling of the printed layer is sufficient to allow the next print to be applied without any further measures.

[0057] In a preferred embodiment, the screen printing device is configured to produce N identical or substantially identical three-dimensional screen prints or print copies, wherein N (a natural number) is greater than or equal to 2; wherein the screen printing device is configured to successively apply the m-th print layer successively to each of the N print carriers for each m from 1 to M; wherein, for each m from 1 to M and for each n from 1 to N, the screen printing device is configured to cause a relative movement between an n-th print carrier (of the N print carriers) and the screen printing cylinder for applying the m-th print layer and simultaneously rotate the screen printing cylinder about its cylinder axis, so that the screen printing cylinder rolls on the n-th print carrier and thereby applies the m-th print layer to the n-th print carrier; and wherein, for each m greater than i and for each n, a distance,During the application of the m-th printing layer, the distance between the n-th printing substrate and the screen printing cylinder for applying the m-th printing layer is greater than the thickness of the (mi)-th printing layer. Thus, the screen printing device first applies the first printing layer successively to each printing substrate, then the second printing layer successively to each printing substrate, and so on, finally applying the m-th printing layer successively to each printing substrate. In particular, for each m, the distance between the screen printing cylinder for applying the m-th printing layer and each of the N printing substrates can be constant during the application of the m-th printing layer to the respective printing substrate. Particularly preferably, for each m from 1 to M and for each n from 1 to N, the screen printing device is configured such that...that the screen printing cylinder, when applying the m-th print layer, rotates at most 360° around its cylinder axis when rolling onto the n-th printing substrate, i.e., at most once (completely). In other words, the screen printing cylinder rolls at most once (completely) onto the printing substrate during the application of the m-th print layer.

[0058] Thus, after each individual print, i.e., a single unwinding of the screen cylinder, a new, independently acting print carrier can be positioned and fed in. Only when all print carriers have been fed in can the distance between the print cylinder and the surface of the print carrier, with the prints or print layers already applied, be increased. The N print carriers can be positioned sequentially, e.g., by a print carriage as described above, or (especially with a larger number of print carriers) guided on a conveyor belt or carrier belt. In particular, the print carrier can be identified, as described above, with the first print carrier of this preferred embodiment; in addition, this preferred embodiment defines the second to Nth print carriers.

[0059] This has the advantage that the N identical or substantially identical screen prints or printed copies can be printed efficiently and at high speed. Furthermore, this method allows for a reduction in the size of the screen printing device, since, even when producing multiple identical printed copies, the one or more screen printing cylinders only rotate once around their cylinder axis when applying each printing layer. In a preferred embodiment, the screen printing device comprises one or more top-side screen printing cylinders and one or more bottom-side screen printing cylinders; wherein the screen printing device is configured to apply M top-side printing layers to a top side of a printing substrate and M bottom-side printing layers to a bottom side of the printing substrate, the top side of the printing substrate being arranged opposite the bottom side of the printing substrate.wherein for each m from i to M the screen printing device is configured to cause a relative movement between the substrate and a pair consisting of a top-side screen printing cylinder for applying an m-th top-side print layer and a bottom-side screen printing cylinder for applying an m-th bottom-side print layer, and simultaneously a rotation of the top-side and bottom-side screen printing cylinders about their respective cylinder axes, such that the top-side screen printing cylinder rolls on the top of the substrate, thereby applying the m-th top-side print layer to the top, and the bottom-side screen printing cylinder rolls on the bottom of the substrate, thereby applying the m-th bottom-side print layer to the bottom;where for each m that is greater than i, a distance during the application of the m-th top-side printing layer, between the top of the substrate and the top-side screen printing cylinder for applying the m-th top-side printing layer is greater by a thickness of the (mi)-th top-side printing layer than a distance during the application of the (mi)-th top-side printing layer, between the top of the substrate and the top-side screen printing cylinder for applying the (mi)-th top-side printing layer;and wherein, for each m greater than i, a distance between the underside of the substrate and the underside screen printing cylinder for applying the m-th underside print layer is greater by the thickness of the (mi)-th underside print layer than a distance between the underside of the substrate and the underside screen printing cylinder for applying the (mi)-th underside print layer during the application of the (mi)-th underside print layer. In particular, the one or more screen printing cylinders, as described above, can be identified with the one or more top-side screen printing cylinders of this preferred embodiment, and the M print layers, as described above, can be identified with the M top-side print layers of this preferred embodiment;In this preferred embodiment, the screen printing device additionally comprises one or more underside screen printing cylinders for applying the M underside printing layers.

[0060] This device allows the top and bottom surfaces of the printing substrate to be printed with multiple layers, thereby increasing the flexibility of the body print. In particular, the top and bottom surfaces can be printed simultaneously, saving time and costs. The present invention further relates to a screen printing method for producing a three-dimensional screen print using one or more screen printing cylinders, wherein the screen printing method comprises: applying M print layers successively onto a printing substrate, where M is greater than or equal to 2;wherein for each m from 1 to M the screen printing process comprises: causing a relative movement between the substrate and a screen printing cylinder (from the one or more screen printing cylinders) for applying an m-th printing layer (of the M printing layers) and simultaneously rotating the screen printing cylinder about its cylinder axis so that the screen printing cylinder rolls on the substrate and thereby applies the m-th printing layer to the substrate; and wherein for each m greater than 1, a distance, during the application of the m-th printing layer, between the substrate and the screen printing cylinder for applying the m-th printing layer is greater by one thickness of the (mi)-th printing layer than a distance, during the application of the (m-i)-th printing layer, between the substrate and the screen printing cylinder for applying the (mi)-th printing layer.

[0061] The screen printing process according to the invention exhibits the same technical effects and advantages as the screen printing device according to the invention, and thus particularly increases user-friendliness. Furthermore, each feature described above in connection with the screen printing device can be implemented analogously in the screen printing process and thus exhibits the same technical effects and advantages.

[0062] As an example, in a preferred embodiment of the screen printing process, the screen printing process comprises L screen panels, where L is greater than or equal to 1. For each m from 1 to M, the screen printing cylinder rotates L times by 360° around its cylinder axis to apply the m-th printing layer as it rolls on the printing substrate.

[0063] As a further example, the screen printing process according to a preferred embodiment is a method for producing N identical three-dimensional screen prints, wherein N is greater than or equal to 2; wherein the method successively comprises, for each m from 1 to M: applying the m-th printing layer successively to each of the N printing substrates; wherein, for each m from 1 to M and for each n from 1 to N, the screen printing process comprises: causing a relative movement between an n-th printing substrate and the screen printing cylinder to apply the m-th printing layer and simultaneously rotating the screen printing cylinder about its cylinder axis, so that the screen printing cylinder rolls on the n-th printing substrate and thereby applies the m-th printing layer to the n-th printing substrate;and wherein for each m greater than 1 and for each n, a distance during the application of the m-th printing layer, between the n-th printing carrier and the screen printing cylinder for applying the m-th printing layer is greater by a thickness of the (mi)-th printing layer than a distance during the application of the (mi)-th printing layer, between the n-th printing carrier and the screen printing cylinder for applying the (mi)-th printing layer.;

[0064] These and other features and advantages of the invention will become clear with reference to the accompanying drawings, which show particularly advantageous embodiments. They show:

[0065] Fig. 1A shows an embodiment of the screen printing device according to the invention during the application of a first printing layer onto a printing substrate; and

[0066] Fig. 1B shows the embodiment of the screen printing device according to the invention during the application of a second printing layer to the printing substrate.

[0067] Fig. 1A shows an embodiment of the screen printing device according to the invention during the application of a first printing layer 4 to a printing substrate 5. The screen printing device comprises a screen printing cylinder 1 for applying the first printing layer 4. The screen printing cylinder 1 comprises a drum screen and a layout carrier that is applied to the drum screen. The layout carrier in Fig. 1A contains hatched areas corresponding to printing areas that are permeable to a substrate 3, and unhatched areas corresponding to blocking areas that are impermeable to the substrate 3.The screen printing device is configured to cause a relative movement (represented by the horizontal arrow) between the printing substrate 5 and the screen printing cylinder 1, and simultaneously a rotation of the screen printing cylinder 1 about its cylinder axis (represented by the curved arrow), so that the screen printing cylinder 1 rolls on the printing substrate 5 and thereby applies the first printing layer 4 to the printing substrate 5. In this embodiment, a receiving device 6 in the form of a printing carriage driven synchronously with the screen printing cylinder 1 receives the printing substrate 5 and guides the printing substrate 5 under the screen printing cylinder 1, pressing the printing substrate 5 against the screen printing cylinder 1. This pressure creates a contact strip.The contact area between the printing carrier 5 and the screen printing cylinder 1 is used to press the printing material 3 from inside the screen printing cylinder 1, through the drum screen and the printing areas of the layout carrier, onto the printing carrier 5 by means of the squeegee 2. As the screen printing cylinder 1 simultaneously rolls across the printing carrier 5, the layout of the layout carrier is transferred to the printing carrier 5 by means of the printing material 3.

[0068] Fig. 1B shows an embodiment of the screen printing device according to the invention during the application of a second printing layer 4 to the printing substrate 5 or to the first printing layer 4. The screen printing device comprises a screen printing cylinder 1 for applying the second printing layer 4. The screen printing cylinder 1 for applying the first printing layer 4 (as shown in Fig. 1A) and the screen printing cylinder 1 for applying the second printing layer 4 (as shown in Fig. 1B) can be the same or different. It is also possible to use the same screen printing cylinder 1 but to exchange the layout carrier of the screen printing cylinder 1 between the application of the printing layers 4. In Fig. 1B, a different layout carrier is shown than in Fig. 1A (different hatched or unhatched areas), so that the second printing layer 4 has a different layout than the first printing layer 4. The substrate 3 from Fig. 1B and the substrate 3 from Fig. 1A can also be the same or different.

[0069] In Fig. 1A, the distance between the substrate 5 and the screen printing cylinder 1 during the application of the first print layer 4 is zero (the outer surface of the screen printing cylinder 1 touches the substrate 5 in this case). In Fig. 1B, the distance between the substrate 5 and the screen printing cylinder 1 during the application of the second print layer 4 is equal to the thickness of the first print layer 4 (the outer surface of the screen printing cylinder 1 touches the first print layer 4). Thus, the distance between the substrate 5 and the screen printing cylinder 1 during the application of the second print layer 4 is greater than the distance between the substrate 5 and the screen printing cylinder 1 during the application of the second print layer 4 by the thickness of the first print layer 4.This ensures that the pressure between the respective screen printing cylinder 1 and the printing carrier 5, and thus the squeegee pressure, remains constant when applying the two printing layers 4.

[0070] List of reference symbols

[0071] 1 screen printing cylinder

[0072] 2 squeegees

[0073] 3 Printed matter

[0074] 4 printing layers

[0075] 5 printing plates

[0076] 6 recording unit

Claims

T33015W0 TERRAMARK Markencreation GmbH Claims 1. Screen printing device for producing a three-dimensional screen print, wherein the screen printing device comprises one or more screen printing cylinders (1); wherein the screen printing device is configured to successively apply M printing layers (4) to a printing substrate (5), wherein M is greater than or equal to 2; wherein for each m from 1 to M, the screen printing device is configured to effect a relative movement between the printing substrate (5) and a screen printing cylinder, from the one or more screen printing cylinders, for applying an m-th printing layer of the M printing layers and simultaneously a rotation of the screen printing cylinder (1) about its cylinder axis, so that the screen printing cylinder (1) rolls on the printing substrate (5) and thereby applies the m-th printing layer to the printing substrate (5);and wherein for each m greater than 1, a distance between the printing carrier (5) and the screen printing cylinder for applying the m-th printing layer is greater by a thickness of the (mi)-th printing layer than a distance between the printing carrier (5) and the screen printing cylinder for applying the (mi)-th printing layer during the application of the (mi)-th printing layer.

2. Screen printing device according to claim 1, wherein for at least one m x between 1 and M and at least one m2 between 1 and M, where m2 is greater than m xThe screen printing device is configured such that, after the application of the middle printing layer to the printing substrate (5) by means of a screen printing cylinder (1), it increases the distance between the printing substrate (5) and the screen printing cylinder (1) by a sum of the thicknesses of the middle to (m2-i)th printing layers in order to apply the m2-th printing layer to the printing substrate (5) by means of the screen printing cylinder (1), wherein preferably m2 = m t + 1 is.

3. Screen printing device according to claim 1 or 2, wherein for each m greater than or equal to 2, the screen printing device is configured such that, after the application of the (mi)th printing layer to the printing substrate (5) by means of a screen printing cylinder (1), it increases the distance between the printing substrate (5) and the screen printing cylinder (1) by the thickness of the (m-i)th printing layer in order to apply the m-th printing layer to the printing substrate (5) by means of the screen printing cylinder (1).

4. Screen printing device according to one of the preceding claims, which further comprises a receiving unit (6) for inserting the printing carrier (5) into the receiving unit (6) and for removing the printing carrier (5) from the receiving unit (6); and wherein for each m from i to M the screen printing device is configured such that it causes a relative movement between the receiving unit (6) into which the printing carrier (5) is inserted and the screen printing cylinder to apply the m-th printing layer and simultaneously a rotation of the screen printing cylinder (1) about its cylinder axis to apply the m-th printing layer to the printing carrier (5).

5. Screen printing device according to one of the preceding claims, wherein the screen printing L comprises screen blanks, wherein L is greater than or equal to 1; and wherein for each m from 1 to M the screen printing device is configured such that the screen printing cylinder rotates L times by 360° about its cylinder axis when rolling on the printing substrate to apply the m-th printing layer.

6. Screen printing device according to one of the preceding claims, wherein the relative movement is a linear movement or a movement along a curved path.

7. Screen printing device according to one of the preceding claims, wherein for at least one m greater than 1, the screen printing device is configured such that the screen printing cylinder for applying the (mi)th printing layer rolls along a (mi)th rolling direction on the printing substrate (5) and the screen printing cylinder for applying the m-th printing layer rolls along a m-th rolling direction on the printing substrate (5); i) wherein the (mi)th rolling direction and the m-rolling direction are identical; or ii) wherein the (mi)th rolling direction and the m-rolling direction differ by 180°; or iii) wherein the (mi)th rolling direction and the m-rolling direction differ by an angle other than 0° and other than 180°, preferably the angle being 90° or 270°.

8. Screen printing device according to one of the preceding claims, wherein the one or more screen printing cylinders (1) are provided with one or more rotary seals, preferably one or more mechanical seals.

9. Screen printing device according to one of the preceding claims, which is further configured to flood one or more interior spaces of the one or more screen printing cylinders (1) with a protective gas or a reaction gas or a sterile gas, preferably such that a gas pressure inside the one or more interior spaces is higher than a gas pressure outside the one or more screen printing cylinders (1).

10. Screen printing device according to one of the preceding claims, which is further configured to provide one or more interior spaces of the one or more Screen printing cylinder (i) is flooded with a carrier gas, wherein the temperature of the carrier gas is higher or lower than the ambient temperature of the screen printing device.

11. Screen printing device according to one of the preceding claims, which further comprises one or more heating elements for heating and / or one or more cooling elements for cooling one or more interior spaces of the one or more screen printing cylinders (1), wherein preferably the one or more heating elements and / or the one or more cooling elements are arranged at least partially or completely within the one or more screen printing cylinders (1).

12. Screen printing device according to one of the preceding claims, comprising one or more heating elements for heating one or more sleeve screens of the one or more screen printing cylinders (1), wherein preferably the one or more heating elements are configured such that they each conduct an electric current through the one or more sleeve screens.

13. Screen printing device according to one of the preceding claims, comprising one or more heating elements for heating one or more squeegees (2) arranged in the one or more screen printing cylinders (1), wherein the one or more squeegees (2) are preferably made of metal.

14. Screen printing device according to one of the preceding claims, which is configured to produce N identical three-dimensional screen prints, wherein N is greater than or equal to 2; wherein the screen printing device is configured to successively apply the m-th printing layer successively to each of the N printing substrates (5) for each m from 1 to M; wherein for each m from 1 to M and for each n from 1 to N, the screen printing device is configured to effect a relative movement between an n-th printing substrate and the screen printing cylinder for applying the m-th printing layer and simultaneously a rotation of the screen printing cylinder (1) about its cylinder axis, so that the screen printing cylinder (1) rolls on the n-th printing substrate and thereby applies the m-th printing layer to the n-th printing substrate;and wherein for each m greater than 1 and for each n, a distance during the application of the m-th printing layer, between the n-th printing carrier and the screen printing cylinder for applying the m-th printing layer is greater by a thickness of the (mi)-th printing layer than a distance during the application of the (mi)-th printing layer, between the n-th printing carrier and the screen printing cylinder for applying the (mi)-th printing layer.; 15- Screen printing device according to claim 14, wherein for each m from 1 to M and for each n from 1 to N the screen printing device is configured such that the screen printing cylinder for applying the m-th printing layer rotates at most 360° about its cylinder axis when rolling on the n-th printing carrier.

16. Screen printing device according to one of the preceding claims, comprising one or more top-side screen printing cylinders (1) and one or more bottom-side screen printing cylinders (1); wherein the screen printing device is configured to apply M top-side printing layers (4) to a top side of a printing substrate (5) and M bottom-side printing layers (4) to a bottom side of the printing substrate (5), wherein the top side of the printing substrate (5) is arranged opposite to the bottom side of the printing substrate (5);wherein for each m from 1 to M the screen printing device is configured such that it causes a relative movement between the printable substrate (5) and a pair consisting of a top-side screen printing cylinder for applying an m-th top-side print layer and a bottom-side screen printing cylinder for applying an m-th bottom-side print layer, and simultaneously causes a rotation of the top-side screen printing cylinder (1) and the bottom-side screen printing cylinder (1) about their respective cylinder axes, such that the top-side screen printing cylinder (1) rolls on the top side of the printable substrate (5) and thereby applies the m-th top-side print layer to the top side, and the bottom-side screen printing cylinder (1) rolls on the bottom side of the printable substrate (5) and thereby applies the m-th bottom-side print layer to the bottom side;wherein for each m that is greater than 1, a distance during the application of the inten top-side printing layer, between the top of the printing carrier (5) and the top-side screen printing cylinder for applying the m-th top-side printing layer is greater by a thickness of the (mi)-th top-side printing layer than a distance during the application of the (mi)-th top-side printing layer, between the top of the printing carrier (5) and the top-side screen printing cylinder for applying the (mi)-th top-side printing layer;and wherein for each m that is greater than 1, a distance during the application of the inten bottom-side print layer, between the bottom of the print carrier (5) and the bottom-side screen printing cylinder for applying the m-th bottom-side print layer is greater by a thickness of the (mi)-th bottom-side print layer than a distance during the application of the (mi)-th bottom-side print layer, between the bottom of the print carrier (5) and the bottom-side screen printing cylinder for applying the (mi)-th bottom-side print layer.; 17- Screen printing process for producing a three-dimensional screen print using one or more screen printing cylinders (1); wherein the screen printing process comprises: applying M printing layers (4) successively onto a substrate (5), wherein M is greater than or equal to 2; wherein for each m from 1 to M the screen printing process comprises: causing a relative movement between the substrate (5) and a screen printing cylinder, from the one or more screen printing cylinders, to apply an m-th printing layer of the M printing layers and simultaneously rotating the screen printing cylinder (1) about its cylinder axis, so that the screen printing cylinder (1) rolls on the substrate (5) and thereby applies the m-th printing layer to the substrate (5);and wherein for each m greater than 1, a distance between the printing carrier (5) and the screen printing cylinder for applying the m-th printing layer is greater by a thickness of the (mi)-th printing layer than a distance between the printing carrier (5) and the screen printing cylinder for applying the (mi)-th printing layer during the application of the (mi)-th printing layer.

Images