DE20022467U1 - Device for cleaning screen printing stencils - Google Patents

Description

WITTE, WELLER & PARTNER Patent attorneys

Rotebühlstrasse 12! · D-70178 Stuttgart

Documents to be entered

Applicant; 29 June 2001

2207G106 AW-sm
CHIM92

4 Rue Salvador Allende
F-69330 MEYZIEU
FRANCE

Device for cleaning screen printing stencils

The present innovation concerns the field of treatment of used printing stencils, in particular those for screen printing.

The innovation relates in particular to a device for cleaning a screen printing stencil provided with ink and with covering agent, in which there is a first nozzle assembly for spraying a cleaning composition onto the stencil, a second nozzle assembly for spraying water onto the stencil and a collecting basin, with a reservoir for the cleaning composition and with a conveyor for conveying the stencil through the chamber.

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Screen printing uses stencils consisting of a frame in which a cloth is stretched. Originally made of silk, but nowadays it is usually made of nylon/polyester with very fine meshes (of the order of 100 μπα). First, a covering agent is applied to these stencils, which closes certain meshes of the cloth, and then an ink is applied, which penetrates through the meshes left open, which in turn correspond to the impression of the image to be reproduced on the print.

For each new image to be printed using this technique, it is necessary to first clean the stencil, removing the masking agent and ink.

Until now, cleaning a stencil involved the following three steps:

In a first step, the stencil is treated with an organic solvent to remove the paint and then rinsed with water under high pressure to remove the solvent and paint residues,

in a second step, an aqueous solution of an oxidizing agent, such as sodium periodate, a so-called decoating solution, is applied to the stencil to remove the masking agent from the closed meshes, and then it is rinsed again under pressure with water, and

In a third step, the phantom image (colour shadow) remaining on the stencil is removed with the help of a

chlorinated agent, and then rinse one last time with water under high pressure.

This cleaning is done either manually or automatically in washing tunnels where the steps are carried out one after the other in different chambers.

Devices used today for this type of cleaning comprise four chambers. Each chamber is assigned a basin, each of which contains an agent for the aforementioned steps.

The first chamber contains a tank containing a solvent that can be used to dissolve the inks used in screen printing. In this chamber, the stencil is sprayed with the solvent contained in the tank using nozzles arranged on a vertical nozzle rod. The vertical nozzle rod is moved horizontally so that the entire surface of the stencil is sprayed. The sprayed solvent drips down into the tank with the ink under the influence of gravity.

The second chamber also contains a tank containing a solvent. This is also sprayed using a vertical nozzle that moves horizontally. This solvent is purer than the solvent in the first tank. To increase the lifespan of the solvents contained in the tanks, circuits are provided for the solvents in the first and second tanks.

Before the stencil moves from the second to the third chamber, it is washed with water under high pressure.

In the third chamber, the corresponding tank contains a decoating agent with which the covering agent can be removed. This agent is also applied using nozzles arranged on a vertical nozzle rod and movable in a horizontal direction.

In the last, fourth chamber, the stencil is washed with water under high pressure.

The stencil is now ready to undergo a further step in which the phantom image is removed.

The stencil will therefore be unavailable during the cleaning period, which may last up to a day or more.

To give an example of the time lost in cleaning a stencil, the last step, which consists in removing the phantom image, is carried out by applying a chlorine and soda-based product to both sides of the stencil and leaving it to act for at least half a day. After this time, the stencil is washed with a solvent to remove any traces of paint, masking agent and chlorinated product. The solvent is left to act, then the stencil is rinsed with water under high pressure. Once dry, the stencil is ready for use again.

Another disadvantage of this type of cleaning is the pollution it generates, because effective solvents, such as halogenated hydrocarbons, are harmful to the environment and are not biodegradable. In addition, the remaining sludge from collected water, solvents and paint is difficult to treat. The solvents are also flammable and therefore dangerous to use, especially in large quantities.

The problem of the difficulty of carrying out the cleaning operation and the length of time it takes has already been studied. Document FR-A-2 354 377 discloses a composition for cleaning stencils which makes it possible to remove the ink and the masking agent simultaneously. The composition consists of a mixture of an organic solvent, in particular γ-butyrolactone, N-methyl-2-pyrrolidone or dimethylformamide (DMF), an oxidizing agent such as sodium periodate, and optionally a surfactant.

However, the treatment of the stencil with this composition is not entirely satisfactory because a previous treatment with petroleum spirit has proved necessary to remove the excess paint. In addition, this composition does not solve the problem of pollution caused by residues of organic solvents and may even involve the use of particularly toxic solvents, such as DMF.

In order to limit the pollution caused by cleaning compositions and their impact on the environment, document WO-A-90/08603 proposes a composition

in which the organic solvents conventionally used are replaced by a mixture of dibasic esters, for example dimethyl ester, selected from a group comprising succinate, adipate and dimethyl glutarate, the mixture being used in the presence of a surfactant. This ester mixture acting on the printing ink is non-toxic and can be biodegraded. The preferred surfactant is non-ionic, for example aliphatic ethoxylated alcohol or ethoxylated alkylphenol. A preferred composition contains between 90 and 100% by weight of the aforementioned ester mixture and between 10 and 0% by weight of aliphatic ethoxylated alcohol.

However, this composition does not always dissolve the resist and its action must be supplemented, in the conventional manner, by a stripping step followed by a treatment with a chlorinated agent to eliminate the ghost image.

In the absence of a truly effective solution, stencil cleaning procedures have remained the same for many years, at least thirty years, despite numerous disadvantages.

According to the innovation, a cleaning device has now been provided which makes it possible to avoid all the disadvantages encountered in conventional cleaning methods, including the special solutions according to the state of the art.

The innovation provides a device for cleaning a screen printing stencil, which in a single step

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allows the paint and the masking agent to be removed simultaneously. The cleaning composition used is very advantageous because, on the one hand, it has a special effect on the substances to be removed from the stencil, but, on the other hand, it does not have any corrosive effect that would damage the cloth or cause it to age prematurely.

The advantage of the cleaning power of the composition used is twofold. Firstly, as already mentioned, this advantage affects the removal of all substances and residues from the mesh of the cloth, but, moreover, it acts almost immediately, so that the period of unavailability of the stencil due to cleaning is significantly reduced.

Despite its effectiveness, the composition is not harmful. Based on non-toxic substances and without any danger to the person who uses it or to the environment, it is very beneficial.

Consequently, the task of the invention is to find a device which avoids the described disadvantages of known devices.

This object is achieved in the device of the type mentioned at the outset in that the first chamber is the only chamber of the device for removing the ink and the covering agent, and that the cleaning composition removes both the ink and the covering agent from the screen printing stencil simultaneously in a single working step.

This applies in particular to a device with at least one first chamber in which there is a first nozzle assembly for spraying a first cleaning composition on the stencil, and a second nozzle assembly for spraying water under high pressure, and which is associated with a first basin for collecting and reprocessing the cleaning agent, wherein the device further comprises a storage for the cleaning composition which is separate from the collecting basin.

In this way, the product sprayed onto the stencil is pure and does not contain any dissolved paint. This results in more effective cleaning and it is no longer necessary to have two chambers for cleaning the stencil. This design also makes it possible to use a common tank for the recovery of the stripping product.

The tank for collecting and recycling the cleaning composition is preferably equipped with a filter system in order to take account of the legal requirements in force at any given time regarding the retention of substances from the sewer system. The filter system is designed in such a way that it does not retain only those substances whose D.CO. (Demande Chimique en Oxygene) is less than 2000.

In a preferred embodiment, the first and second nozzle blocks are attached to each other so that they form a unit.

The nozzles are preferably arranged horizontally. In this case, during spraying, it is preferable to use

movable nozzle holders and a fixed template. The nozzle holders move advantageously from bottom to top and then from top to bottom in order to achieve a good cleaning effect.

In order to perfect the cleaning, the device preferably contains motor-driven rotating brushes whose axis of rotation is substantially at a right angle to the plane of the template.

In one embodiment, the nozzle rods are movable relative to the stencil to be cleaned, which remains stationary during the spraying of the cleaning composition and water, as already highlighted above. In any case, it would also be possible to use a movable stencil and stationary nozzle rods. In this case, the nozzle rods would preferably extend in a vertical direction.

In order to achieve a better cleaning effect, the device advantageously contains a second, double nozzle rod, which is arranged in such a way that the stencil to be cleaned is located between its two individual nozzle rods and can be sprayed on both sides.

Preferably, the device contains two dosing units, one of which receives a predetermined amount of sodium metaperiodate solution and sulphuric acid, and the other a predetermined amount of a mixture of dialkyl esters and a non-ionic surfactant, the dosing units being provided with a water supply. In one dosing unit, an aqueous solution of sodium metaperiodate is obtained, and in

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The other dosing unit produces an aqueous solution of a mixture of dialkyl esters and a non-ionic surfactant. The absorbed substances are stored in reservoirs located inside or outside the device. The dosing devices operate hydraulically or electrically.

When, in the context of the present innovation, the term 'solvent' is used in connection with the compositions used, it should be noted that the alkyl ester mixtures envisaged in this regard are not classified in the VOC (Volatile Organic Compounds) class under the relevant European provisions since, unlike conventional organic solvents, they are not toxic.

In order to also enable the removal of any phantom images that may be present, the device advantageously contains a second chamber that is provided with a spray unit that can be moved relative to the stencil. This spray unit has, for example, a double nozzle assembly, one of which is used to spray an agent for removing phantom images and the other nozzle assembly is used to spray water under high pressure.

In order to enable rapid drying of the agent for removing ghost images, the second chamber is advantageously equipped with a pulsating ventilation system that allows hot air to be introduced into the second chamber. To improve the drying process even further, the second chamber can be provided with a nozzle rod that can be moved relative to the stencil and with which air can be blown against the stencil. Even better drying

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is achieved if the first chamber has a nozzle rod that can be moved relative to the stencil, whereby this nozzle rod is an air intake rod that initiates a drying process of the stencil.

In order to avoid the appearance of streaks on the stencil as it passes through the device according to the invention, means are advantageously provided for causing the stencil to vibrate. In this way, a better distribution of the flow on the stencil is obtained during the rinsing and drying steps, which leads to the avoidance of the appearance of streaks which would correspond to the edges of the spray zones of two adjacent nozzles.

In the device according to the invention, a composition is preferably used which contains:

an aqueous solution containing between 0.05 and 5 wt.% sodium metaperiodate and between 0.05 and 0.75 wt.% sulphuric acid, and

a solution of between 0.5 and 90 wt.% of a mixture of dialkyl esters and between 0.5 and 50 wt.% of a non-ionic surfactant.

The percentages mentioned in the present description and the claims are given as the weight of the components in relation to the weight of the solution, if a solution is defined as above, or in relation to the final weight of the composition, if the composition is defined as

defines how this will happen in the further course of the description.

Consequently, the ratios of the various components of a composition according to the invention to one another are defined in such a way that a compound adapted to the particular colour to be removed is obtained.

Advantageously, a composition of the type defined above further contains between 1 and 15% by weight of periodic acid.

A special innovative composition contains:

between 0.05 and 5 wt.% sodium metaperiodate,

between 0.05 and 0.75 wt.% sulphuric acid,

between 1 and 15 wt.% periodic acid,

between 0.5 and 90 wt.% of a mixture of dialkyl esters,

between 0.5 and 50 wt.% of a non-ionic surfactant.

A composition in accordance with the innovation also corresponds to the following characteristics, each alone or in combination with each other.

The mixture of dialkyl esters contains or consists of a mixture of glutarate, succinate and dialkyl adipate; preferably it is a mixture of glutarate, succinate and dialkyl adipate, in which the proportions of the components are preferably 61 - 67% glutarate, 20 - 26% succinate and 13 - 19% adipate.

The non-ionic surfactant is an alkylphenol ethoxide (alkylphenol ethoxylate), preferably nonylphenol ethoxide (nonylphenol ethoxylate).

A particularly suitable composition contains:

an aqueous solution of between 0.1 and 0.5% by weight of sodium metaperiodate and between 0.1 and 0.5% by weight of sulphuric acid,

an aqueous solution of between 1 and 20 wt.% of a mixture of dialkyl esters and between 1 and 22 wt.% of a non-ionic surfactant.

In the device according to the invention, the screen printing stencil is exposed to one of the compositions defined above.

For this purpose, the two aqueous solutions of the composition are mixed together before the exposure step.

Preferably, the stencil is exposed to the composition by spraying or evaporation.

After this exposure time, which can vary between one and five minutes, the stencil is rinsed with water, preferably under high pressure.

The implementation of the described process does not require large facilities; a single chamber is sufficient to process the stencil

to the cleaning composition, rinse and dry.

In the device according to the invention, a kit for cleaning and decoating a used screen printing stencil is preferably used, the kit comprising a first vessel containing a solution, optionally an aqueous solution of alkylphenol ethoxide (alkylphenol ethoxylate) and of dialkyl esters, and a second vessel containing an aqueous solution of sodium metaperiodate and sulphuric acid.

The innovation will be understood from the following description, which describes a preferred example of a composition according to the innovation, and from the attached schematic drawing, which shows, as a non-limiting example, a preferred embodiment of a device according to the innovation. In the drawing:

Figure 1 is a partially broken away perspective view of the device according to the invention; and

Figure 2 is a sectional view taken along line II-II in Figure 1.

A device for applying the composition according to the invention is described below with reference to the figures mentioned above:

Fig. 1 shows a cleaning device with which it is possible to remove ink from stencils 2 used in screen printing, to remove the coating and to remove particles located thereon.

tom images. The device comprises a first chamber 4 and a second chamber 6. Both chambers are box-shaped. The dimensions of the device are adapted to the dimensions of the stencils to be cleaned.

By means of a conveyor, a template 2 is introduced into the first chamber 4 and then transferred to the second chamber 6. The conveyor comprises a motor-driven conveyor chain 8 and an upper guide 10. The template 2 is placed on the chain 8 and held in a vertical position by means of the upper guide 10. An opening 12 provided in an outer wall of the first chamber 4 enables the template 2 to be placed on the conveyor.

The first chamber 4 is assigned a reservoir 14, which is intended to hold a cleaning solution, as well as a pump 16 for pumping the agent in the reservoir 14, a high-pressure pump 18 for pumping water, a drain basin 20, a double nozzle assembly 22 and a chain system 24 for moving the double nozzle assembly 22.

The reservoir 14 is designed to accommodate a composition according to the innovation. The pump 16 serves to pump the composition contained in the reservoir 14 to the double nozzle assembly 22. The double nozzle assembly 22 is arranged horizontally. It is formed by two horizontal nozzle assemblies 26, 32 arranged parallel to one another, which are fastened to one another. A first nozzle assembly 26 is connected to the pump 16 via a flexible pipe 28. This first nozzle assembly 26 is provided with small nozzles 30 which are used to spray the composition in the reservoir.

rather 14 contained agent. The pressure set for spraying is, for example, between 2 and 4 bar.

The second nozzle assembly 32 of the double nozzle assembly 22 is connected to the high pressure pump 18 via a flexible pipe 34. The second nozzle assembly 32 is provided with larger nozzles 36, with which the water can be sprayed under a high pressure of approximately 120 bar. The double nozzle assembly 22 is arranged horizontally. The chain system 24 enables a motorized movement of the double nozzle assembly 22 from bottom to top and then from top to bottom. The double nozzle assembly 22 is connected near its two edges to a chain, which in turn runs around two rollers, one of which is driven by a motor. This system is known to the person skilled in the art and therefore does not need to be explained in more detail in the context of this description. However, any other system that allows the double nozzle assembly to be moved can also be used.

On the other side of the template 2 there is a simple nozzle holder 38, which can be used for drying by suction. This nozzle holder 38 also extends horizontally and can be moved from bottom to top and then from top to bottom by means of two chain systems 24 of the same design as described above.

The collecting basin 20 is located under the template 2 and the endless chain 8. This basin 20 serves to collect the agent and water that drip downwards under the influence of gravity after they have been sprayed by one of the nozzle rods 26, 32 of the double nozzle rod 22. The collecting basin

20 is connected to the sewerage system via a filter system. If the composition indicated above is used, the basin 20 can be connected directly to the sewerage system because the composition is biodegradable. In any case, however, for reasons of water saving, the collecting basin 20 can also be connected to a filter system in order to recover the water. Consequently, the high-pressure pump 18 can either be supplied with water directly from a supply network or the supply can be made via the recycled water. The filter system is not shown in the drawing, but can of course be integrated into the device.

If desired, the second chamber 6 can be of a design very similar to that of the first chamber 4. Therefore, in the second chamber 6 there is also a reservoir 40, a pump 42 connected to this reservoir, a high-pressure pump 44 for pumping water and a collecting basin (not shown). Likewise, on one side of the conveyor chain 8, which also runs through the second chamber 6, there is a double nozzle rod attached to two chain systems of the same design as the chain systems 24. On the other side of the conveyor chain 8 there is also a single nozzle rod attached to two chain systems. For reasons of clarity, this double nozzle rod and the single nozzle rod are not shown in the drawing.

The memory 4 0 contains a means known to the person skilled in the art that allows the removal of ghost images (color shadows) that are on a screen printing stencil. This

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The agent is a chlorinated gel. The pump can be used to feed the agent contained in the reservoir 40 to a nozzle assembly of the corresponding double nozzle assembly via a flexible pipe (not shown). The agent intended to remove the ghost image is then sprayed in the nozzles at a pressure of approximately 2 bar. The high-pressure pump 44 is connected to the other nozzle assembly of the double nozzle assembly of the second chamber 6 via another flexible pipe. This nozzle assembly also contains nozzles intended to spray the water at a pressure of approximately 120 bar.

The single nozzle holder, in contrast to the single nozzle holder of the first chamber 4, is provided with nozzles from which hot air is blown. With the aid of a fan and a heating resistor, neither of which are shown in the drawing, it is possible to supply air at approximately 30° to the nozzle holder, from where it is blown in the direction of the template 2.

The collecting basin collects the agents which drip from the stencil 2 under the influence of gravity. In addition to the nozzle which emits warm air, a system 4 6 for the pulsed application of air can be provided in the area of the second chamber 6.

The device therefore works as follows:

The template 2 is automatically taken by the conveyor chain 8 and with the help of the upper guide 10 into the interior of the first chamber 4. The double nozzle holder 22 is in its lower position. As soon as the template 2 is in place and

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position, the nozzle assembly 26 is supplied with the composition according to the innovation using the pump 16. The double nozzle assembly 22 then begins its upward movement. As soon as it has reached above the stencil 2, it is moved downwards, constantly spraying the composition. The excess of this agent, mixed with the paint and the covering agent, then drips down into the collecting basin 20. After the agent has been allowed to act on the stencil 2 for a few seconds or a few tens of seconds, the second nozzle assembly 32 of the double nozzle assembly 22 is supplied with water using the high-pressure pump 18. The double nozzle assembly 22 then moves upwards again until it reaches above the stencil 2, whereupon it is moved downwards until it is back in its starting position. In this way, the stencil 2 is completely rinsed. The rinsing water, which is mixed with the composition, the colors and the covering agent, is now in the collecting basin 20.

The stencil 2 is now pre-dried using the suction nozzle assembly 38. The nozzle assembly 38 is also moved upwards from its starting position below the stencil 2 until it is above the stencil 2, and then moved back to its starting position. In this way, the excess water is removed from the stencil 2. The stencil 2 preferably oscillates horizontally from left to right to prevent the formation of vertical stripes. This oscillation movement is caused by a cam arrangement (not shown). The oscillation amplitude is, for example, a few centimeters.

As soon as the suction nozzle assembly 38 has returned to its starting position, the stencil 2 is moved into the second chamber 6. The agent for removing the phantom images is now sprayed using the nozzles of one of the nozzle assembly of the double nozzle assembly of this chamber 6. The agent is fed to the nozzle assembly using the pump 42. This is moved from bottom to top and then from top to bottom so that the agent is sprayed over the entire surface of the stencil 2. The pulsating ventilation system 46 is then switched on. It feeds air into the interior of the chamber 6 in an attempt to keep it at a temperature of around 30°. A dehumidification device (not shown) can be assigned to the pulsating ventilation system 46 so that dry air is sent into the second chamber 6. Meanwhile, the single nozzle which emits warm air is moved from bottom to top and then again from top to bottom so that warm air is blown onto the entire stencil 2 and the agent for removing any ghost images is thoroughly dried. In this case, several passes of the blowing nozzle can be made from bottom to top and then from top to bottom. The agent for removing ghost images works when dry. As soon as this agent is thoroughly dried and has taken effect, the double nozzle in the second chamber 6 is supplied with pressurized water using the high-pressure pump 44. The nozzle is then moved from bottom to top and then from top to bottom so that it sprays the water over the entire surface of the stencil 2 with each pass. The sprayed water and the agent for removing ghost images then drip into the collecting basin in the second chamber 6.

In order to avoid vertical stripes forming on the template 2, it is also possible to provide for the template 2 to oscillate in a horizontal direction in the second chamber. Here too, an oscillation movement with an amplitude of a few centimeters is sufficient.

As soon as the stencil 2 has been rinsed, it is automatically moved out of the second chamber 6 and the device described above. It can then either be received manually or one can equally imagine an automatic plate for receiving stencils 2 at the exit of the second chamber 6. In a similar way, one can also provide an automatic loading station for the stencils 2 at the entrance to the first chamber 4.

In a preferred embodiment, an aqueous composition for cleaning stencils used in screen printing is obtained as follows:

First, take 20% by weight of alkylphenol ethoxide (alkylphenol ethoxylate),

add 13% of a mixture of commercially available dimethyl esters,

Dissolve the whole in 66.4% water,

add 0.25% sulphuric acid, and

0.25 wt.% sodium metaperiodate is added.

The composition thus obtained makes it possible to clean a screen printing stencil by simultaneously removing the inks and covering agents contained on the stencil.

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In general, after application of the cleaning composition described above, it is no longer necessary to use a ghost removal agent. It is understood that depending on the color and which emulsions have been used, the mixing ratios given above may vary.

The composition obtained in this way is non-flammable. Its pH is slightly acidic (between 5.5 and 6). It is not harmful and complies with European standards on biodegradability, which require a minimum biodegradability of 90%.

The cleaning composition described above can be easily filtered after use. After filtering, the water can be recovered and used for rinsing under high pressure.

It is understood that the innovation is not limited to the embodiment described above, which is to be understood as merely exemplary and not restrictive. On the contrary, the innovation also includes all embodiments that fall within the scope of the protection claims specified below.

For example, instead of a single reservoir for the composition in the area of the first chamber, two separate reservoirs can be provided, one of which contains an aqueous solution containing between 0.05 and 5% by weight of sodium metaperiodate and between 0.05 and 0.75% by weight of sulphuric acid and the other an aqueous solution containing between 0.5 and 90% by weight of a mixture of dialkyl ethers and between 0.5 and 50% by weight of

a non-ionic surfactant. One and the same nozzle could spray both of these agents at the same time.

The fact that the nozzle rods move from bottom to top or from top to bottom is a preferred embodiment. A vertical nozzle rod moving in a horizontal direction could also be provided.

The fact that a double nozzle holder is provided (for the composition and the water) is to be understood as an option. Of course, two separate nozzle holders can also be used.

Cleaning a stencil using the new method does not necessarily result in the formation of a ghost image. In the majority of cases, it is therefore not necessary to provide a second chamber at all.

The suction nozzle holder and the blow nozzle holder are also to be understood as options. This also applies to the devices intended for oscillating the nozzle holders, which are also to be understood as options.

Within the scope of this innovation, any other conveying system, loading system or unloading system for the stencils can also be provided.

Claims (14)

1. Device for cleaning a screen printing stencil ( 2 ) provided with ink and with a covering agent, with a first chamber ( 4 ) in which there are a first nozzle assembly ( 26 ) for spraying a cleaning composition onto the stencil ( 2 ), a second nozzle assembly ( 32 ) for spraying water onto the stencil ( 2 ) and a collecting basin ( 20 ), with a reservoir ( 14 ) for the cleaning composition and with a conveyor ( 8 , 10 ) for conveying the stencil ( 2 ) through the chamber ( 4 ), characterized in that the first chamber ( 4 ) is the only chamber of the device for removing the ink and the covering agent, and that the cleaning composition removes both the ink and the covering agent from the screen printing stencil simultaneously in a single work step. 2. Device according to claim 1, characterized in that the storage ( 14 ) and the collecting basin ( 20 ) are separated from each other. 3. Device according to claim 1 or 2, characterized in that the first ( 26 ) and the second ( 32 ) nozzle assembly are fastened to one another in such a way that they form a unit ( 22 ). 4. Device according to claim 3, characterized in that the unit ( 22 ) is arranged so that the stencil to be cleaned ( 2 ) is located between the two nozzle rods ( 26 , 32 ) and can be sprayed on both sides. 5. Device according to one of claims 1 to 4, characterized in that the nozzle rods ( 26 , 32 ) are arranged horizontally. 6. Device according to one of claims 1 to 5, characterized in that it contains motor-rotatable brushes whose axis runs substantially at a right angle to the plane of the template. 7. Device according to one of claims 1 to 6, characterized in that the nozzle rods ( 22 ) are movable relative to a stencil ( 2 ) to be cleaned, which remains spatially fixed during the spraying of the cleaning composition and the water. 8. Device according to one of claims 1 to 7, characterized in that the reservoir ( 14 ) contains two dosing devices, one of which receives a predetermined amount of a solution of sodium metaperiodate and sulfuric acid, and the other of which receives a predetermined amount of a solution of a mixture of dialkyl esters and a non-ionic surfactant, and that the dosing devices are connected to a water supply. 9. Device according to one of claims 1 to 8, characterized in that it has a second chamber ( 6 ) which is provided with a device which can be moved relative to the stencil ( 2 ) for spraying the agent for removing phantom images. 10. Device according to claim 9, characterized in that the movable device for spraying has a double nozzle block, in which one nozzle block serves for spraying and the other nozzle block serves for spraying water under high pressure. 11. Device according to claim 9 or 10, characterized in that the second chamber ( 6 ) is provided with a pulsating ventilation system ( 46 ) with which warm air can be introduced into the second chamber. 12. Device according to one of claims 9 to 11, characterized in that the second chamber ( 6 ) has a nozzle rod which can be moved relative to the stencil and with which warm air can be blown against the stencil. 13. Device according to one of claims 9 to 12, characterized in that the first chamber ( 4 ) has a nozzle assembly ( 38 ) which is movable relative to the stencil ( 2 ) and is designed as a suction nozzle assembly for initiating drying of the stencil. 14. Device according to one of claims 1 to 13, characterized in that a device for oscillating the template is provided.