WO1993011943A1

WO1993011943A1 - Inking-pad printing press

Info

Publication number: WO1993011943A1
Application number: PCT/CH1992/000237
Authority: WO
Inventors: Louis Bachmann
Original assignee: Louis Bachmann
Priority date: 1991-12-09
Filing date: 1992-12-08
Publication date: 1993-06-24
Also published as: EP0571571A1; ATE136257T1; JP3219766B2; DE59205914D1; CH688442A5; EP0571571B1; AU2940192A; JPH06508574A

Abstract

The inking-pad printing press proposed has an ink reservoir (7) which is open underneath and which is pressed by a piston/cylinder unit on to a mobile printing plate (6). The reservoir (7) is connected by an articulated joint to the piston (15) of the piston/cylinder unit (12), the articulated joint being located inside the reservoir (7), near the upper surface of the printing plate (6). If the upper surface of the printing plate (6) is inclined at an angle, the ink reservoir (7) can adjust itself in any direction to the plate inclination so that a uniform pressure is exerted by the whole of the end of the ink reservoir (7). Thus even if the upper surface of the printing plate is inclined, the printing quality is excellent.

Description

Tairipon printing machine

The invention relates to a pad printing machine according to the preamble of independent patent claim 1.

A machine of this type is known from DE-C-1 923 374. This has an ink container open at the bottom, which rests on a reciprocating gravure printing plate, also called a cliché. The paint container has a wedge-shaped edge at the bottom of an edge resting on the plate. When the container is full, this color is applied when the printing plate is moved. By means of a stamp, the print image is transferred to a print item after an ink application. It is essential that the container is constantly pressed resiliently against the pressure plate, which is done here with a helical compression spring.

If the upper side of the printing plate is skewed with respect to the ink container in such a machine, for example as a result of an assembly error or an error in the carriage on which the printing plate is mounted, this leads to an uneven application of color and finally an unsatisfactory print.

A similar pad printing machine is known from DE-A-37 37 937, in which the ink container is designed in the area of its end face in such a way that it can bend or twist in this area. For this purpose, an elastic seal in the form of an O-ring is used, for example, in the paint container above the end face. Furthermore, a pressing device is provided which has three points of the hollow body which act substantially diametrically opposite one another and point upward-pointing surfaces. These points are arranged on a pressure ring on which a pressure force is applied at two points on a diameter line. With these structurally complex measures, a decoupling between the lower region and the upper region of the ink container and finally an adaptation of the front surface of the ink container to a crooked or uneven cliché should be possible. It is considered important here that the paint container is held close to the face. An additional pressure ring is thus provided here so that the pressure force is distributed to some extent evenly over the end face of the paint container.

A tampon printing machine is also known in the prior art, in which the ink container by means of a magnet is pressed against the pressure plate. With this, an oblique pressure plate is not a problem in itself. However, there are now many colors that chemically and physically unfavorably change in a magnetic field, and which therefore cannot be used in such a machine. With such a machine, the selection of suitable colors is therefore comparatively small.

The invention has for its object to provide a tampon printing machine of the type mentioned, which is structurally simpler and in particular does not require a separate pressure ring and which nevertheless delivers excellent printing results even with an inclined printing plate. The paint container should be easy to assemble and replace and should also be easy to manufacture. The object is achieved by the invention according to claim 1. The subject of a subsidiary claim is an ink container which is particularly suitable for the tampon printing machine.

In the tampon printing machine according to the invention, the pressing device in the interior of the ink container is connected to the latter. In the case of a paint container with a circular end face, the contact pressure can then be applied exactly on the center line to the end face and near the pressure plate. This point is then as far away as possible from all points on the end face and the contact pressure is thus distributed evenly over the end face. A pressure ring that distributes the pressure force over several points is therefore not necessary here. It is also advantageous that the outside of the paint container has no parts for attaching the pressing device and that it is therefore freely accessible from the side for mounting and replacement. The contact pressure is evenly distributed over the face of the paint container if it does not have hard material such as hardened steel. In the tampon printing machine according to the invention, it is also possible to exert the contact pressure on the ink container near the top of the printing plate.

According to a development of the invention, it is provided that the container can be pivoted in all directions with respect to the pressing device, as in the case of a ball joint. The ink tank can then adapt to any inclination of the printing plate. According to a further embodiment of the invention, this is achieved by a ball-and-socket bearing.

A particularly simple and suitable articulated connection is created according to a further development of the invention in that a cover of the paint container has a recess on the top side in which a hemisphere socket is arranged which forms a joint with a ball pin inserted into this opening. The ball pin is preferably inserted loosely from above into this preferably cylindrical recess. A particularly simple pressing device has one, for example pneumatic cylinder, with the free end of the piston being articulated to the paint container. The contact pressure is then exerted by this pressure cylinder. To replace the paint container, simply hold the paint container and retract the piston. The contact pressure of the cylinder can be checked and adjusted periodically using a suitable control device.

A major advantage of the tampon printing machine according to the invention is further seen in the fact that it is also possible to work with non-circular, for example elliptical, angular and in particular rhombic ink containers. These containers are then preferably held at at least two spaced locations.

Further advantageous features result from the dependent claims, the following description and the drawing. Exemplary embodiments of the tampon printing machine according to the invention are explained in more detail below with reference to the drawing. Show it:

1 is a view of a partially cut tampon printing machine according to the invention,

2a and 2b each have a vertical section through a

Ink tanks, a cliché and a cliché holder,

3 shows a side view of the tampon printing machine according to the invention, Fig. 4 is another view of the partially sectioned

Pad printing machine, Fig. 5a and 5b vertical section and plan of an ink container according to a variant Fig. 6a and 6b vertical section and plan of an ink container according to another variant.

The pad printing machine shown in FIGS. 1, 3 and 4 has a housing 1 with a bottom 1 a on which a slide guide 3 for a reciprocable slide 2 with a carrier 4 and a pressure plate 6 is attached. The pressure plate 6, also called a cliché, is inserted into the carrier 4 from above and this is in turn fixed with screws 5 on the carriage 2. With a drive, not shown here, the carriage 2 for coloring the printing plate 6 is moved from the position shown in solid lines in FIG. 3 to the dash-dotted position and then brought back into the original position. If the printing plate 6 is colored, the ink remaining on the printing plate 6 is transferred to the object to be printed with a tampon 40.

For inking the printing plate 6, an ink container 7 is provided, which is open at the bottom and rests below with a circumferential and comparatively sharp edge 8 under vertical pressure on the upper side 6a of the printing plate 6. Inside the container Color 7 is not shown here, which is applied during the movement of the carriage 2 into the position 2 'shown in FIG. 3 and is scraped off by means of the edge 8 during the return movement. An embodiment is also conceivable here in which the carriage 2 is fixed with respect to the housing 1 and the container 7 is moved. The relative displacement between the container 7 and the slide 2 or the pressure plate 6 is therefore essential.

It is also essential that the edge 8 rests evenly on the upper side 6a over the entire circumference, even if, as shown in FIG. 2b, the upper side 6a 'is flat but not horizontal. Even an inclination that is significantly less than the inclination shown exaggerated in FIG. 2b inevitably leads to an unsatisfactory pressure if this is caused by an uneven pressure of the edge 8 over the circumference. An inclination of the upper side 6a can have different causes, for example an inaccurate machining of the pressure plate 6, inaccuracies in the guide 3 or tolerance deviations on the slide 2. The surface 6a can thus be inclined in all directions. So that the ink container 7 can adapt in all directions to a possibly inclined upper side 6a of the pressure plate 6 ', this has an extension 9 which extends into the interior of the ink container 7 and which has a recess 19 which is connected to a piston 15 of a pneumatic Cylinder 12 forms a ball pin bearing. The pneumatic pressure cylinder 12 is fixed to the housing 1 with a fastening part 10 and screws 11. The paint container 7 is thus held by the piston 15, so that the paint container 7 is not moved horizontally when the carriage 2 is displaced. The projection 9 is arranged centrally with respect to a cylindrical wall 17 and also with respect to the edge 8 and is integrally formed on a ceiling wall 18. The recess 19 is cylindrical at the top and merges in the lower region of the attachment 9 into a hemisphere socket 19a, against which an articulated ball 15a of the piston 15 slidably abuts. The ball 15a merges via a neck 15b into a cylindrical part 15c which has an outer diameter which is somewhat smaller than the inner diameter of a cylindrical region 19b of the recess 19. The longitudinal axis A) of the recess 19 is thus limited in all directions pivotable with respect to the longitudinal axis B) of the piston 15. Since, as mentioned above, any inclination of the upper side 6a is generally only very slight, a correspondingly slight pivotability is sufficient here.

The piston 15 presses on the hemisphere socket 19a from above with a force which is exerted essentially constantly by the pressure cylinder 12. For this purpose, the cylinder 12 is connected via ports 14 to valves (not shown here) and a suitable control. The use of a pressure cylinder 12 has the essential advantage that the contact pressure of the piston 15 and thus of the ink container 7 can be automatically monitored and controlled. It is now essential that the contact pressure to protect the container 7 and the pressure plate 6 can be kept comparatively small. This is achieved by the uniform support of the edge 8 over the entire circumference. This uniform support is in turn a consequence of the pivoting of the paint container 7 on all sides.

In order to change the ink container 7, it is held by hand on the pressure plate 6 and the piston 15 is moved upwards by actuating the cylinder 12 into the position shown in dash-dotted lines in FIG. 1. The container 7 can then be removed from the slide with the carrier 4 after the screws 5 have been removed. The new ink container is then inserted into the carriage 2 with the support 4 and the pressure plate 6. The piston 15 is then moved downward from the retracted position and its lower end is inserted into the recess 19b. After the support 4 has been fixed with the screws 5, the machine is ready again. The desired contact pressure is set independently by the pneumatic control device. Tensioning or re-tensioning a spring with levers and the like is therefore not necessary here.

Since the projection 9 extends downward into the interior of the container 7, as can be seen, it is very easily possible to comparatively close the location at which the piston 15 acts on the container 7 to the top 6a to arrange. At the same time, however, this attachment point is comparatively far away from the edge 8 and, in relation to this, is as far away as possible everywhere. This prevents the edge 8 from being deformed by an asymmetrical force effect.

In the wall 18 of the paint container 7, an opening 16 is provided for pressure equalization in a known manner.

5 and 6 or 5a and 6a show two paint containers 20 and 30 which, in contrast to the circular container 7, are elongated. The container 20 is approximately elliptical when viewed from above and the container 30 is hexagonal. A rectangular and elongated container is also conceivable. “An opening 23 or 33 is also provided for pressure compensation in these containers. The containers 20 and 30 are held with at least two pressure cylinders 12 in such a way that the pressure plate 6 is moved in the direction of the shorter diameter. The elongated shape of the pressure container 20 or 30 has the advantage that, compared to a circular design with the same content, the movements of the pressure plate 6 can be kept shorter. So that a compensation to a possibly oblique upper side 6a of a pressure plate is guaranteed and the contact pressure is nevertheless distributed as uniformly as possible over the entire area of the edge 8, two lugs 24 and 34 are provided here, which are arranged at a distance from one another and as symmetrically as possible are. In the embodiment according to FIG. 5, the lugs 24 are arranged approximately where the focal points of a corresponding ellipse are located. The approaches 24 and 34 also have one Recess 26 or 36 open at the top into which a piston 15 is inserted. The ball pans are formed here by inserts 25 and 35, respectively. In these versions, too, it is ensured that the container 20 or 30 can adapt to an inclined upper side 6a, the axes of the pistons 15 then being inclined to the corresponding axes of the projections 24 or 34. If the connecting line of the two lugs 24 and 34 is also inclined, the pistons automatically adapt to this inclination by appropriate retraction or extension.

The containers 20 and 30 have a lower edge 22 or 32, which each consists of a different material than the remaining part 21 or 31 of the container 20 or 30. The edge 22 or 32 can be made of ceramic, for example. However, the containers 20 and 30 can also be made in one piece from a suitable plastic, as is also provided for the container 7.

In the exemplary embodiments explained above, the connection between the container and the piston or pistons 15 is a ball joint. However, other known joints are also possible which permit a similar movement between the piston (s) 15 and the paint container. It is important here, however, that a substantial proportion of the force to be exerted on the container 7 acts on the container 7 within it. An embodiment is also conceivable in which the pneumatic pressure cylinder 12 is replaced by other similarly acting means, for example by a compression spring.

Claims

PATENT CLAIMS

1. Pad printing machine with an ink container (7, 20, 30) for inking a printing plate (6) that can move back and forth relative to the ink container and with a pressing device (12) for pressing the ink container (7, 20, 30) onto the print ¬ plate (6), wherein the paint container (7,20,30) is articulated to the pressing device (12), characterized in that the pressing device (12) within the container (7, 20,30) is connected to it .

2. pad printing machine according to claim 1, characterized ge indicates that the pressing device (12) via a Kugel¬ joint (15a, 16a) with the container (7,20,30) is connected.

3. Pad printing machine according to claim 1 or 2, characterized in that at least one recess (19, 26, 36) is arranged in a top wall of the container (7, 20, 30) and extends downward into the container interior and in which engages a joint part (15a) of the pressing device (12).

4. Pad printing machine according to one of claims 1 to 3, characterized in that the container (7) is circular in the horizontal section and the pressing device (12) is connected centrally to the container (7).

5. Pad printing machine according to one of claims 1 to 4, characterized in that the pressing device (12) is a pressure cylinder, the piston (15) of the cylinder releasably connected at its front end to the container (7, 20, 30) is.

6. Pad printing machine according to claim 5, characterized in that the printing cylinder (12) is fixedly connected to a housing (1) of the pad printing machine.

7. Pad printing machine according to one of claims 1 to 6, characterized in that the ink container (20, 30) is elongated and that it is connected to the pressing device at at least two spaced apart locations (25, 35).

8. pad printing machine according to claim 7, characterized ge indicates that the end face (8) of the container (20) is approximately elliptical or rectangular and that within the container (20) two articulated connections (25) arranged approximately above the focal points are provided.

9. container for a pad printing machine marked by the corresponding features of claims 1 to 8.