HRP920833A2 - Tampon-printing device for transferring specific quantities of printing medium per unit area - Google Patents

Abstract

In the printing pad device described, the surface of the pad (20) is recessed while retaining essentially the same external form and volume. Also described is the use of the pad for at least partially coating a substrate (22) with a predetermined pattern. The substrate (22) is a printed circuit board for manufacturing integrated circuits, a component of a pharmaceutical presentation and/or dosage form, a label with raised characters, a prepolymer or similar.

Description

The technical field to which the invention belongs

The invention belongs to the field of devices for applying liquid or other liquid substances to surfaces, as well as to the field of printing devices, and especially relates to devices for applying paint. Designation according to the International Classification of Patents: B05C 1/06, B41L 27/26.

Technical problem

The invention solves the problem of how to design a device for printing with a pad, which will enable an increase in the contact area of the pad while maintaining the same external shape and volume of the mold in which the pad is located.

State of the art

Pad printing devices have been known since 1968 and are suitable for printing uneven surfaces, to which flexible pads, which transfer the printing medium, or imprinting are adapted. One pad printer is described, for example, in DE-OS 19 39 437. The shape element to be printed is hollowed out by etching in a cliché, or impression mold. The printing medium is fed into this plate, after the scraping operation, which dispenses the printing material in the plate, the buffer completely takes over the printing material left in the mold and transfers it to the object to be printed on. An overview of the applications and properties of the pad printing process can be found in the prospectus of TAMPOPRINT GmbH, Daimlerstrasse 27/1, Krontal-Munchigen, which is referred to in order to avoid repetition in its entirety.

Pad printers are very convenient due to the small required space, because they can be easily integrated into production lines, and can also be placed in envelopes, which is convenient when processing highly active or toxic printing media, such as medications, etching liquids, polymerization initiators or similar, for the protection of workers, but also to reduce the rate of evaporation of unstable substances.

Until now, no attempt has been made to use pad printers to transfer precisely regulated amounts of printing media. Unexpectedly, it turned out that already known tampon printing procedures enable accurate dosing of surface masses up to 26 g/m2 in one printing operation, with deviations within + 2% or less.

In doing so, it is possible, as shown in the parallel German patent application "Procedure for the production of a matrix for the release and/or dosing of medicinal active substances by means of a single printing process", filed on the same day as this one, by the same applicant, that very sensitive medications or regulatory membranes for the release of active substances with a contact surface mass are applied to the appropriate substrates.

The use of previously known means, such as changing the material of the pad (a softer pad transfers more printing media) and the viscosity of the printing media, could only ensure a slightly increased, practically constant, in quantity, release of the printing media onto a substrate. This amount was not, however, sufficient for the application of layers of higher specific mass, for example over 100 g/m2, so that the pad printing process, despite its outstanding properties, has so far not been suitable for applications such as the production of thicker layers of material according to one advance arranged pattern or shape, so it was not of interest for layering with this process.

Expensive screen printing procedures or complicated procedures for applying multiple layers were used.

Description of the solution to the technical problem

Therefore, the aim of the invention is to further develop the existing devices in such a way that larger amounts of printing media, which is possible with existing tampons, can be transferred to a substrate.

This goal was achieved, according to the invention, by a device of the described type, in which the minimum contact area for printing the entire surface of the tampon is increased while maintaining the same external shape and volume of the mold.

Increasing the surface can consist of embossing, roughening, grooving, or creating small bumps on the surface of the tampon, and this can be achieved by processing a finished tampon body, or creating an increased tampon surface by deforming the tampon body into a suitable shape.

These pads can, compared to existing pads with a smooth surface, transfer more than three times the amount of printing medium, with the same pad shape.

Further development according to the invention of the well-known tampon printer enabled for the first time the use of these machines, that is, the process, in a favorable way in gradually new areas of application, for the production of various covers, etc. Thus, this printer can, for example, be used for the production of shields with a thick layer of paint, integrated circuits, where a layer of photo varnish or conductive material can be applied, for the intentional application of polymerization initiators to prepolymers, for the application of etching liquid for the production of patterns, etc. by etching, for the application of colors to porcelain, for the production of pharmaceutical matrix for release and/or dosing, such as tablets, systems that are applied through the skin, whereby this includes systems that deliver materials through the mucous membrane, so for rectal and vaginal forms of application.

It is especially suitable for use in the production of therapeutic systems in the form of patches for action through the skin.

With the invention, the amount of printing media transferred in a single printing operation can be increased in an unexpected manner, while still maintaining the dosing within narrow limits of accuracy.

With the device according to the invention, it is possible for the first time to produce printing media containing active substances in the desired form, then small doses of active substances without loss of active substances, which was the case until now with the methods used for applying layers of substances to surfaces, such as therapeutic systems that work through the skin, which saves expensive active substances and can avoid the problematic removal of active substance waste.

Furthermore, it is possible that in one production step, by applying appropriate clichés, multiple printing agents can be applied simultaneously and spatially clearly separated from each other, such as, for example, multiple colors, colors and glue, glue and one aseptic area, or an area containing active substances , with patches or therapeutic systems, which saves one production step. Both the cliché and the buffer can be brought to the desired temperature, or can be processed only in a warm state, as individual glues. In the same way, these parts, as well as the entire device, can be cooled, if temperature-sensitive materials are processed or modified.

By choosing the appropriate material for the tampon, various requirements can be taken into account, so that the expert can easily choose elastic materials, such as natural and synthetic rubber, and especially silicone rubber, and depending on the solvents, heat resistance or sufficient elasticity at low temperatures.

The shape of the tampon can be chosen according to the substrate to be treated. It can have all the usual shapes, so tampons in the shape of a hemmed cone, flat or egg-shaped with an increased printing surface can be used.

With one printing, the device according to the invention can transfer a mass per unit area of about 200g/m2 of printing medium, and even more, whereby the expert can further increase the transferred amount by improving the process, such as the use of softer pads, other printing media and the like.

Other properties and advantages of the invention will be explained with reference to the attached drawings, whereby:

- picture 1 shows a pad printer when applying a layer of printing medium to a substrate,

- picture 2 shows the printer with the buffer from picture 1 when taking a new printing medium from the cliché,

- figure 3 shows the buffer according to the invention with an increased surface,

- figure 4 shows the second buffer according to the invention with an increased surface,

- figure 5 shows a section of a therapeutic system in the form of a patch, which acts through the skin, made with a device according to the invention,

- figure 6 shows a horizontal projection of a layer of active substances with two different active substances, made by a pad printing device according to the invention,

- Figure 7 shows a matrix for releasing medication in the form of a dragee, made with the device according to the invention.

Figure 1 schematically shows the application of a layer of printing medium on a flat substrate 22 by means of a buffer 20 made according to the invention. In doing so, an elastic egg-shaped buffer 20 made of silicone rubber, on which there is a layer of printing medium on the raised part 23 of the surface, which was taken in the previous working stage of the device from one recess, which corresponds to the desired shape of applying the printing medium, and which is shaped in cliché (see figure 2), presses on a flat surface 22, on which, after lifting the tampon 20, one even layer of the printing medium remains. In the same way, printing can be done on uneven substrates, for example on rounded substrates, or on wavy surfaces of coverings, as well as on substrates in the form of containers, etc.

Figure 3 shows a suitable construction of the egg-shaped tampon 20 according to the invention, on whose upper part 23, which serves to transfer the printing medium, there are grooved depressions as an increase in surface area, which enable the taking and transfer of larger amounts of printing media. In this procedure, the amount of printing medium taken will be determined by the depth and shape of etching of the cliché 24, from which the entire amount of printing medium is taken, and after it is distributed on the cliché in one scraping operation in the form of a layer of uniform thickness, whereby the medium will to print in that form and download and upload.

Figure 4 shows another embodiment of the buffer 20, which here has a cylindrical shape. Small indentations are made on the surface of the receiving, or transferring, pad in order to increase the surface area, which serves to accept increased amounts of printing media.

Figure 5 shows a patch containing active substances, made with the device according to the invention. This patch can be made by evenly applying one annular layer 16 of acrylic adhesive, impermeable to the active substance, on one cover film 15, in this case on siliconized paper, which is separated before using the patch, as well as one round regulatory layer 18, which with its constant thickness and chemical-physical properties regulate the passage of material, and then by printing the reservoir layer 14 containing the active substance using the pad printing device according to the invention, and finally by laminating with one impermeable carrier layer, in this case laminate 10 of aluminum and polyester. With the device according to the invention, it is possible to apply both the regulating layer 18, whose properties can only be achieved with a large constant thickness, and the active substance layer 14, whose active substance content can only be maintained in a suitable form for application with a large constant thickness and surface area of the applied layer. for pharmaceutical purposes.

Figure 6 shows one patch, such as the one from Figure 5, before the placement of the carrier layer 10, wherein this patch has two active substances 14 and 14'. And this execution can be carried out in a single step by applying the active substance using the pad printer according to the invention, whereby the ring 16 of glue impermeable to the active substance can also be seen in the picture.

Figure 7 shows a pharmacological matrix for releasing glue, which can be made with the device according to the invention, in the form of a sugar-coated dragee 30, with a two-layer core 34, 36, which can be made by printing the layer 36 on the circular base 34 without waste material of the base 34 or printed layer 36.

Other implementations, combinations and application of the device according to the invention are possible within the scope of the knowledge available to the expert, and are within the scope of the protection covered by the patent claims.

Claims (4)

1. Pad printing device for transferring defined amounts of printing media to a unit area, characterized by the fact that the pad surface (2), while maintaining essentially the same external shape and volume, is increased. 2. Device according to claim 1, characterized in that the increase in surface area consists in the formation of depressions, roughness, grooves or small protrusions at least on the part (23) of the surface of the pad, which serves to transfer the printing medium. 3. Device according to claim 1 or 2, characterized in that the increase in the surface of the tampon (23) is done by processing the finished body of the tampon (20). 4. Device according to claim 1 or 2, characterized in that the increased part (23) of the tampon surface can be made by molding the tampon body (20) into a suitable shape.