DE2855769A1 - METHOD AND DEVICE FOR INDIRECT, DISCONTINUOUS TRANSFER OF LIQUID MATERIALS - Google Patents

Description

AGFA-GEVAERT 5090 Leverkusen, Bayerwerk

SHARED COMPANY

Patent department HRS / W

21. EET. 1978

Method and device for the indirect, discontinuous crossing of liquid materials.

The invention relates to a method and a device for the indirect, discontinuous transfer of liquid materials, these materials being stored in a storage container, a cliché with indentations is present in the cliché surface for receiving the materials, a squeegee device for Cleaning of the cliché surface is provided and an elastic transfer part, called a tampon, for Pick-up and transfer of the material remaining in the depressions of the cliché to the one to be coated Surface is provided.

In the printing industry, methods for the continuous indirect printing of materials are known in which a cliché roller dips into ^a supply of printing material and wets itself and then through a 030028/0188

Squeegee that located on the surface of the cliché Printing material is doctored off, so that printing material remains only in the depressions (engraving). This The material remaining as a print image is taken over by an elastic pressure pad roller and transferred to the The goods to be printed are transferred by unrolling or pressing on. Here the pressure pad material is like this ensure that the surface of the cliché can just barely pick up the printing material and onto the Almost all of the goods to be printed are lost.

For this purpose, the transfer cylinder consists of silicone rubber with preferably high elasticity, and The printing materials used are screen printing inks based on plastic or synthetic resin or also stoving colors. A printing process and a corresponding device are described in DE-OS 21 26 described.

Indirectly and discontinuously operating printing devices are also known, in which liquid Materials by means of an elastic transfer part, generally called a tampon, from a cliché, whose wells were filled with the materials, removed and placed on a part to be printed be transmitted.

With these devices for printing, the print image is in a cliché plate made of steel or copper

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engraved. The liquid printing material comes from an open material tray with a brush device Spread over the cliché and doctored off the excess printing material. After that takes over the pad removes the printing material by pressing it onto the cliché. By applying the with Pad with printing material on the part to be printed, the printing material is attached to the part to be printed Part delivered. There are several options for the mechanical process. Devices are possible in which the tampon is fixed and alternately with it Color-filled cliché and the part to be printed are pressed against the pad, or with which the pad is movable and pressed alternately onto the cliché and the parts to be printed will.

Such a printing process is described in DE-OS 1,939,437. Can be used as printing materials only relatively evaporation-resistant materials based on plastic or synthetic resin or stoving varnishes used.

Since the printing materials are removed from an open material tray in this process, an constant evaporation of solvents. In order to maintain the quality of the print, frequent readjustments are

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fill and a constant dilution of the paint is required. This shows that only possible evaporation-resistant Printing materials for this process are desirable, but which on the other hand require a long drying time of the printed parts require.

Are printing materials processed that are harmful or highly flammable, volatile? Contain components., So must these hazards by an additional suction can be encountered, reducing the undesirable evaporation of the compared to the Volume very large surface of the material supply in the paint tray is further increased.

Certain materials, such as glue or hotmelts, cannot be extracted from an open material supply process, as these cool down too quickly on the surface of the material supply and / or stick to the Decompose air.

Another disadvantage of the known devices is the encrustation of the printing material on the container for the supply, on the cliché and the squeegee, so that frequent work interruptions for cleaning are necessary are. With every major standstill of the device when changing clichés or printing material It also requires cleaning time, with paper always being lost.

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The invention is based on the object of a method and to find a device which, with a simple construction, also allow printing materials to use the highly volatile, flammable, decomposing in the atmosphere or extremely harmful Have components or materials that can only be processed when they are warm are.

This object has been achieved according to the invention in that in the case of the method and the corresponding device, the supply of the liquid material, a roller body with the cliché and the squeegee device in a container that is largely closed to the outside are encapsulated that

a discharge opening of the container through the roller body is closed as far as possible that the rotation during the removal stroke of the tampon of the roller body is interrupted so that a depression in the cliché surface of the discharge opening is assigned and that

an additional lock is provided, which is only opened during the removal stroke and then closed again will.

According to a particular embodiment, to interrupt the rotation of the roller body in the Delivery position a pawl actuated by the tampon on the downstroke switched on, which turns into a ratchet wheel intervenes.

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The tampon also controls the additional closures at the removal opening by means of a mechanical, pneumatic one or electromechanical control so that it is on the downward stroke of the tampon to remove material open and close on the upstroke after removal.

According to a special embodiment, the additional locks can only be closed for longer periods Standstills are carried out by a timer, so that the additional locks open at high cycle rates stay.

The additional locks can be designed both as a sliding device or as a folding mechanism.

An embodiment suitable for high quality requirements has an inlet and outlet nozzle, by means of which the level in the container and the viscosity can be regulated by circulation from the outside.

There is a special embodiment with a suction nozzle for processing toxic or very volatile substances intended to generate and maintain a negative pressure in the container.

In order to achieve high cycle rates, a device is used, which is to be coated or to be printed Materials are brought in and out in a timed manner.

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For the processing of hot glue, hotmelt and similar materials that are to be processed warm according to a particular embodiment, the container and the tampon are heated.

Due to the surprisingly simple construction, namely only the use of a container, its opening is closed with a roller that rotates through a supply of material and the use of the Surface of this roller as a cliché, with one of the depressions at the moment of the removal stroke of the tampon is assigned to the opening of the container in a defined position, there is a considerable expansion this procedure to areas of application that were previously closed. So can in addition to the previously The screen printing inks and stoving enamels used are now also harmful, volatile and possibly flammable materials that decompose if exposed to air are used. Even the Use of thick to pasty materials is in the process and with the device possible.

With the encapsulation can also be advantageously connected to a metering and circulating device for a constant viscosity adjustment of the material to be transferred ensures an even application guaranteed. Additional heating for heating hot glue or hotmelt material can also be provided.

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partially insert.

With the largely tight design of the device, it is extremely dangerous when processing substances only necessary, instead of a suction with high air output over the device inside the Container to maintain a slight negative pressure, which, however, does not result in any significant evaporation arises.

Since the processability and quality of the material to be transferred is constantly maintained by the present invention, especially in connection with a level control and a viscosity control device t , it is possible to run the machine without supervision during continuous operation with automatic supply and removal of the parts to be printed permit. Even with single cycle operation, even after long breaks between two printing processes, the machine is immediately ready for use. It has also been shown that at the end of the work the removal of the material to be transferred and careful cleaning of the device are no longer necessary. The time required for this and the associated loss of material are eliminated. In addition, it has surprisingly been found that the structurally complex solution for the reciprocating movement of the material application brush and the squeegee is achieved by a rotational movement of the cliché with the cliché constantly in engagement

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Doctoring can be simplified to its extent.

A particular advantage of the invention is that when it is necessary to change the cliché or the liquid material, the entire container can be exchanged so that the device is immediately ready for use again after a short downtime.

The number of cycles is not limited by the liquid material, since it is π i in a closed System is located and spraying is not possible as with brush application.

Further advantages, features and possible applications are linked from the following description with the accompanying drawings.

It shows:

Figure 1 is a partial section of an inventive

Device with a schematic representation of the work cycle of the tampon

Figure 2 is a partial section of a device according to the invention with an additional closure, which as Sliding device is executed in the open state during the removal stroke of the Tampons

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away

FIG. 3 shows a partial section of the device according to the invention according to Figure 2 with the sliding device closed

FIG. 4 shows a partial section of the device according to the invention, with one in the form of a folding mechanism trained additional lock, in the open state

Figure 5 shows a partial section of the device according to the invention, according to Figure 4 with the closed Folding mechanism.

FIG. 1 shows the device according to the invention for the discontinuous, indirect transfer of liquids Materials in a schematic representation. The printing material supply 1 is located in an encapsulated System, which is designed in this preferred embodiment as a closed container 2, the has a dispensing opening 3, at which the material to be transferred from the tampon through the removal stroke 14-13 is taken over by the roller surface serving as a cliché from the depressions 6.

Only during this removal stroke 14-13 of the tampon is the constant rotation of the roller body and the the cleaning of the cliché surface 5 taking place by the squeegee device 7 and interrupted

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Latching a latch 8 in a ratchet wheel 9 for the assignment of a material provided Well 6 for dispensing opening 3 provided.

After the removal stroke 14-13 of the tampon 12 during the Lifting off into the upper lift position 14 closes at the same time that shown in FIGS. 2, 3, 4 and 5 Additional closure 10, 11 from the opening 3 hermetically. At the same time, the latch 8 is also disengaged brought with the ratchet wheel 9 and thus restarted the rotation of the roller body.

After reaching the upper stroke position 14, the tampon 12 is shifted laterally up to the level of the surface 16 to be coated and lowered onto this surface 16 for material transfer (14-15).

Thereafter, the tampon 12 is raised again into the upper stroke position 14 and laterally back over the Level of the removal stroke 13 shifted. The tampon 12 is thus ready for material removal again. During the working strokes of the tampon 12, the rotation of the roller body 4 through the material supply through the emptied recess 6 is again filled with printing material.

Since between the discharge opening 3 of the container 2 and the roller 4, a certain gap is required to the Not to scratch cliché surface 5 is one

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Complete sealing cannot be achieved at this point.

The entire width of the im also acts as a seal Inside the container 2 arranged doctor blade 7 at. According to the invention, however, an additional closure 10, 11 can be arranged which ensures complete encapsulation in the event of longer downtimes. The additional lock / Mon, 11 is open during the removal stroke 14-13 of the tampon 12. With a single measure with a subsequent longer one When the machine is idle, the additional lock 10, 11 is opened at the removal stroke 14-13 and after the material transfer by the tampon 12 again immediately closed. In the case of a continuous printing sequence with a high number of cycles and a small time difference between the work cycles the additional lock can remain open all the time. The closing of the additional lock after completion continuous operation can be carried out by a timer, which is activated when a certain downtime is exceeded the machine ensures that the dispensing

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4 *

Opening is closed by the additional closures 10, 11.

Figures 2 and 3 show the preferred embodiment of the device according to the invention with an as Sliding device 10 trained additional lock. This sliding device 10 is only during the removal stroke 14-13 open, as shown in Figure 2, and is in the closed position after the material has been removed State as shown in Figure 3.

Figures 4 and 5 show a further advantageous embodiment of the device according to the invention with an as Folding mechanism 11 executed additional closure, which corresponds to Figure 4 at the removal stroke 14-13 of the Tampon 12 is open and, according to FIG. 5, is closed State after the material has been removed.

The printing device can be driven purely mechanically, with a motor driving the roller body 4 via a Friction drives and the tampon 12, the latch 8 and the additional lock 10, 11 via a mechanical one Gearbox are operated. A variable speed motor is advantageously used, so that each different cycle rates of the printing process can be selected according to the task.

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It is also possible to drive the roller body in friction with a motor and all other movements to be carried out pneumatically or hydraulically with pistons and cylinders. Here the Tampon 12 for controlling the latch 8 and the additional closure 10,11 on its downward stroke 14-13 Initiate control.

In a special embodiment, the particular is suitable for fully automatic operation, the liquid material 1 is continuously circulated, by being supplied and discharged via the connection 18. Via a level control and a viscosity control As is known, there is always liquid material 1 in the same quantity and quality within of the container 2.

In order to prevent the escape of evaporated components of the liquid material 1 to the outside, can A small negative pressure can be maintained in the container via a suction nozzle 17.

The construction of the device is advantageously designed so that the container 2 with roller body 4 and Squeegee device 7 and the closure devices 10, 11 can be replaced as a complete component, so that when switching to another liquid material 1 or another printing block 5, only a short interruption arises.

For an automatic operation of the device at a high cycle rate, the parts to be printed

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on transport devices 19 such as belts, chains or ratchet wheels in a known manner. The device according to the invention also allows the application of hot glue or hotmelt to those to be bonded Parts or bands if the container 2 and the tampon are equipped with heating.

The method and the device in their embodiments are both for those used so far in practice Plastic or synthetic resin paints or for stoving enamels, whereby the short changeover times, show the saving of cleaning times as particularly advantageous and large quantities enable printed parts in a very uniform quality.

The method and the device can be used for volatile, poisonous or decomposing substances, whereby large quantities are possible due to the short drying times of the printed parts will. For the first time, however, it is also possible to print hot melts and hot melts in a discontinuous printing process to apply to parts and tape-like materials.

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Claims (1)

- vf- Claims 1) Process for the indirect, discontinuous transfer of liquid materials in a Storage containers are stored and applied to a cliché with depressions, with a Squeegee device cleans the cliché surface and then an elastic transfer part, called Tampon that picks up materials located in the depressions of the cliché and moves towards one coating surface, characterized in that that a device is used in which the supply of the liquid printing material (1) of the roller body (4) with the cliché (5) and the squeegee device (7) in one outwardly largely closed container (2) are encapsulated that the container (2) has a dispensing opening (3) which is closed as far as possible by a rotating roller body (4) and that depending on the movement of the tampon (12) at its removal stroke (14-13) the rotation of the cliché (4) is interrupted so that a depression (6) the cliché surface (5) remains at the dispensing opening (3) of the container (2), - the additional closures (10, 11) provided shortly before the tampon (12) is placed on the cliché surface (5), controlled by the tampon (12), can be opened, O30Q2S / OiäS 'NSPECTED - «re - - the material (1) is removed through the tampon (12), - During the upward stroke (13-14) of the tampon (12) an additional lock (10,11) is closed and the Rotation of the roller body (4) can be started again - and in that the tampon (12) on the part to be coated (16) for Mater: is brought .alübergäbe, wherein the clocked parts to be coated (16) with a conveyor (19) on and be ^removed. (2)) Device for performing the method according to - Claim 1, wherein for the indirect, discontinuous transfer of liquid materials this are stored in a storage container, a cliché with indentations in the cliché surface for receiving the materials is available, a squeegee device for cleaning the cliché surface is provided and an elastic transfer part, called a tampon, for receiving and transferring of the material remaining in the depressions of the cliché onto a surface to be coated is provided, characterized in that - The supply of the liquid printing material (1) the roller body (4) with the cliché (5) and the Squeegee device (7) encapsulated in a container (2) which is largely closed to the outside are, © 30028/018 - The dispensing opening (3) of the container (2) closed as far as possible by the roller body (4) is, - During the removal stroke (14-13) of the tampon (12), the rotation of the roller body (4) is thus interrupted is that a recess (6) in the KlIseheefläche (5) is assigned to the dispensing opening (3), - An additional lock (10, 11) is provided which is open during the removal stroke (14-13) and is then closed. 3) Device according to claim 2, characterized in that to interrupt the rotation of the Roller body (4) a pawl (8) and actuated by the pad (12) during the downward stroke (14-13) a ratchet wheel (9) are provided. 4) Device according to claim 2, characterized in that to open and close the additional lock (10, 11) on the removal opening (3) of the container (2) one through the downstroke (14-13) and one through the Upward stroke (13-14) of the tampon (12) influenced mechanical, pneumatic or electromechanical Control is present. AG 1620 _. _A. 030028/0188 - se - 5) Device according to claim 2, characterized in that a timer is provided for opening and closing the additional lock (10, 11). 6) Device according to claim 2, characterized in that the additional closure (10) is designed as a sliding device. 7) Device according to claim 2, characterized in that the additional lock (11) as a folding mechanism is trained. 8) Device according to claim 2, characterized in that on the container (2) an inlet and an outlet nozzle (17) are attached through which the Level of the printing material (1) in the container (2) and its viscosity due to circulation from the outside is adjustable. 9) Device according to claim 2, characterized in that a suction nozzle (17) is provided to maintain a negative pressure in the container (2). 030028 / 018® - 21 - 10) Device according to claim 2, characterized in that that a device (19) for the clock-controlled automatic supply and removal of the parts to be printed (16) is provided. 11) Device according to claim 2, characterized in that the container (2) and the tampon (12) can be heated are. AG 1620 030028/0188