EP0790081B1 - Apparatus for coating substrates - Google Patents

Description

The invention relates to a device for Surface coating or for painting substrates or disk-shaped substrates such as a disk-shaped Information carrier, which on the substrate carrier agents to be applied or the paint liquid applied to the substrate via a feed device becomes.

It is already a surface coating device or for painting disc-shaped substrates or Compact Disks known for this purpose on a Substrate carrier are arranged by means of a drive device is rotated. Such devices do not work satisfactorily, in particular because the in the device filter device located relatively easily adds and because paint fluids with high viscosity are not so easy to use because they often do tend to clog the filter provided in the system.

EP-A-0 334 535 describes a method for surface coating a known electrical cable. Liquid released from the cable Coating material is collected in a collecting container, on a filter passed on and from the filter by means of a pump into the collecting container returned.

The invention has for its object an improved Device for surface coating or to paint substrates, at which too perfect for liquids with high viscosity Operation of the entire device can be maintained can.

The object is achieved in that in the fluid circuit between a first drain line of the first container and a second container or / and the pump a vacuum pump (30) integrated or or to the Device is connected. There the liquid thrown off the substrate carrier or the liquid paint medium through a first collecting container is passed to a first filter, the System a vacuum device is connected or a negative pressure is generated, liquid medium can also or high viscosity paint through the Move the filter system and the desired one for the liquid Achieve purity and trouble-free conveying. Due to the vacuum operation, filters can also be used very close-meshed filter elements are used, without reducing the throughput time of the lacquer throughout Device is adversely affected. By the advantageous use of negative pressure operation can filters of this type are also in use for considerably longer remain as next to the pump in connection with the vacuum a high flow rate of the coating liquid is ensured.

For this purpose, it is also advantageous that the substrate carrier dispensed liquid medium or the paint at least is delivered to a first collecting container, which is connected to at least one filter from which the liquid directly or indirectly via a Pump is directed to the first container, where between the first tank and the pump a vacuum pump integrated or connected to the device is, the substrate carrier via a drive device drivable or in a rotational movement is relocatable.

An additional option is according to a training the device according to the invention that between a second container for the filter and the pump of the liquid medium and the vacuum pump to one Return device is connected.

In a further embodiment of the invention, it is advantageous that to the second container for receiving the liquid medium the vacuum pump is connected and that the vacuum pump is designed as a venturi nozzle, which is connected to the second container. Because the vacuum pump, which is also designed as a venturi nozzle may be behind the filter the paint liquid in the attached to the filter subsequent container pulled so that next to the geodetic height as delivery pressure the vacuum, which is generated by the vacuum pump as a funding can be used. In advantageous Way is the vacuum pump or the venturi to the Top of the second container connected so that above the liquid level of the paint Gas medium or the air from the second container at least partially evacuated and thereby the liquid medium from the filter to the second collection container can be pulled. Advantageously, the Outlet line of the filter to the second container connected so that, for example, gas inclusion showing medium through this facility in addition can be degassed and sources of error in the paint layer almost completely excluded on the substrate can be.

According to a preferred embodiment of the invention Solution is finally provided that the first container via a liquid line and a the first valve interrupting the inflow to the filter is connected to the filter and that the first container via a liquid line and a second valve either with the container or a third valve is connectable to the tank. Because the first container can be shut off from the filter with a valve the filter even during the work of the whole Device replaced without decommissioning the system be because the upper container by appropriate Facilities sufficient with paint medium for the maintenance work can be filled so that an interruption of the work process or the Painting can be avoided.

By using a tank that also works with the Supply system is connected, the system automatically supply paint when in the second container the paint liquid is reduced to a minimum has been.

In connection with the device according to the invention it is advantageous that between the filter and the a second shut-off valve is provided and that between the second container and the pump Check valve is provided.

It is also advantageous that the pumped Liquid or the paint over a Heater connected to the nozzle of the feeder is. By using a heater in the supply line to the container it becomes possible in a simple way heat the paint liquid so that a even application of varnish on the surface of the substrate is guaranteed. By lowering the viscosity will also be unevenness in the layer surface avoided, and thereby the error rate when applying paint reduced.

To ensure that the paint is properly fed to the surface to ensure the substrate, it is advantageous that the substrate or the substrate carrier by means of a guide device or in such a setting is adjustable that the feed device for application the liquid or the paint in the area of Substrate approximately parallel to the surface of the substrate performed and at any point above the Substrate can be stopped.

It is also advantageous that the feed device connected to the drive device and by a Feeder is included and that the Carrying device by means of the guide device in adjustable horizontally and / or vertically is.

In a further embodiment of the invention, it is advantageous that the drive device with a stepper motor or electrical or electro-hydraulic Stepper motor is operatively connected and that the Drive device has a stepper motor, the via a gear or rack or worm gear drivingly connected to the guide device is. By using a guide device with a degree guidance device ensures that an exact, exact approach of the feeder is possible in the place of the substrate at which the paint application is planned. This will create a uniform fall height between the exit end of the Nozzle and the surface reached, so that too an even coat of paint is guaranteed. By the use of a stepper motor can be controlled precisely the feed device to the desired one Be ensured above the substrate.

In a further embodiment of the invention, it is advantageous that the liquid from the substrate carrier (14) Medium or the varnish (4) at least to a first one Container (27) is dispensed with at least a filter (28) is connected, from which the liquid directly or indirectly via a pump (29) the first container (27) is passed, whereby between a first drain line (33) of the first Container (27) and the pump (29) a negative pressure is adjustable.

Figur 1

eine schematische Darstellung der gesamten Vorrichtung zum Lackieren von Substraten bzw. Compact Disks (CD),

Figur 2

einen Lackierkopf mit einer zugehörigen Leitvorrichtung zum Auffangen des abgeschleuderten Lacks und zum Absaugen des Lacknebels,

Figur 3

eine Zuführeinrichtung mit einer Düse, die über eine Kulissenführung in horizontaler und vertikaler Richtung verstellt werden kann,

Figur 4

eine Schnittdarstellung entlang der Linie A-A gemäß Figur 3.

Further advantages and details of the invention are explained in the patent claims and in the description and illustrated in the figures, it being noted that all individual features and all combinations of individual features are essential to the invention. It shows:

Figure 1

1 shows a schematic representation of the entire device for painting substrates or compact disks (CD),

Figure 2

a painting head with an associated guiding device for collecting the thrown off paint and for vacuuming the paint mist,

Figure 3

a feed device with a nozzle that can be adjusted in a horizontal and vertical direction via a link guide,

Figure 4

3 shows a sectional illustration along the line AA according to FIG. 3.

In the drawing, the entire device is in Figure 1 for surface coating or for painting substrates 2 with 1, to which a painting head 49 heard, which is illustrated in more detail in Figure 2.

The painting head 49 is according to FIGS. 1 and 2 via a Shaft 54 connected to a drive motor 60.

The painting head 49 has a guide device 18, made up of two truncated pyramids, firmly connected guide elements 19, 20, which has openings Fins 56 with a substrate carrier or plate 14 firmly are connected. The upper part of the guide element 19 of the Guide device 18 extends with respect to the central axis R inclined and pyramidal towards the top. On the guiding device 19 closes, as already mentioned, the lower, also to the central axis R tapered guide element 20. The guide device 18 opens into an annular channel 57, which according to a line Figure 1 opens into a first container 27 and which is formed in a coaxial part 25 with a central bore 26.

A liquid or a lacquer 4 (FIG. 3) passes over a feed device 6, as from the closer below 3 and 4, and an associated nozzle 5 on the substrate 2, while the substrate 2 is rotating via the motor 60 is transferred. In this process, the paint 4 flows as a result the centrifugal force on the surface of the substrate 2 radially outwards and passes over the edge of the substrate and the guide device 18 in the ring channel 57. Additional excess paint particles are in Form of a paint mist from the surface of the substrate 2 hurled. These paint parts are made by one second ring-shaped, attached to the outer contour of the guide element 19 adjoining guide device 22 suctioned off, a suction opening in the lower area 24 has, so that the guide 22 captured paint particles also the first container 27 can be supplied. The centrifuged paint liquid gets through the Painting head 49 or the associated guide elements 19, 20 and the associated outlet openings 23 in the first Container 27. The first container 27 is over a liquid line 33, which acts as a return line is formed, and via a first control valve 34 a liquid line 59 connected with her upper end au the upper end of a container 35 and with its lower end to an inlet opening 74 of a filter 28 is connected.

A second valve 36 is located in line 59, through which the tank 35 via line 59 with the inlet opening 74 of the filter 28 can be connected when paint liquid 4 from the tank 35 through the filter 28 are fed to a second container 31 should. For this purpose, the outlet opening 61 of the filter 28 via a line 43 to the upper end of the second container 31 connected. The lower End of the container 31 is also a valve 37 and a line 39 with a second inlet opening 62 of the filter 28 in connection, so that the im Filter remaining filtered liquid in the second container 31 can expire when the filter cartridge of the filter 28 is to be changed. The Filter 28 has a centrally arranged tube 75 equipped to ensure that liquid flows over the upper end of the tube and thus the filter cartridge always completely in liquid.

The coating liquid passes from the first container 31 4 'via a line 47 to a pump which as Dosing pump 29 can be formed. The pump 29 will driven by a stepper motor 63, so that at one corresponding control impulse paint liquid from the Container 31 via the metering pump 29 and a Line 46, a control valve 51, an electric heater 39 and the line 47 fed to the painting head 49 can be.

The pump or the metering pump 29 also protrudes a line 45 and a control valve 52 with the first Container 27 in connection. So that the pump or Diaphragm pump 29 can work properly is under the dosing pump 29 a check valve 38 is provided.

Check valve 38 ensures that only the paint liquid 4 'from the second container 31 is conveyed to the first container 27.

So that a perfect supply of the two paint containers or containers 27 and 31 with paint liquid ensures the entire device 1 one or two level indicators 40 on that via an electrical line 71 with a Evaluation unit or control or regulating device 69 is connected via which the individual valves or electrically or pneumatically operated valves 34, 36, 37, 51, 52 and 30 can be controlled can to the paint liquid in the desired direction or to the individual containers 27, 31 and to guide the substrate 2.

According to FIG. 1, the fill level indicator 40 consists, among other things, of two sensors 41, 42 arranged at a distance from one another, which are accommodated in the upper container 27 and in the lower container 31, which is also referred to as the second container 31. The first sensor 41 has a height H ₁ and the second sensor 42 has a height H ₂ with respect to a floor 53.

In the container 31 there are also two identical sensors 41, 42, which have an upper measuring point with the height H ₁ and a height H ₂ with respect to the bottom 53. These two measuring points of the two sensors 41, 42 can be wetted by the paint. The sensors 41, 42 are supplied with a DC voltage, the resistance value to the housing being measured. The different filling level in the container 27 or 31 influences the resistance value. The signal evaluation of the measured values of the two sensors 41, 42 can be recalibrated at any time when the liquid introduced into the container 27, 31 wets the two measuring points.

The sensors 41, 42 and the container 27, 31st are each via an electrical line 71 to the Evaluation unit 69 connected by means of the measured values the sensor 41 and 42 detected and the so determined Measured values from the different heights as a control variable used to control the individual valves, for example the two containers 27 and 31 to supply with liquid medium and at a certain Degree of contamination, the switching valve 34 to Close filter 28.

During the filling process of the liquid or the lacquer 4 in a container can be empirically called a Background curve or measurement curve (resistance above the filling level) so that these Curve later when measuring the height of the liquid in the Containers are available as a relative reference size stands. Because after long use of the circulating paint liquid the moisture content in the paint changes it is important to have a continuous calibration the resistance elements or sensors becomes. After such a calibration can even with only one sensor, for example with the sensor 42, the actual size or the fill level can be determined in the container 27 and / or 31. The measuring points or resistance values determined in this way give the operator information about the respective filling status Information about when, for example, the lower collecting container 31 again via the tank 35 new paint or over the container 27 with used Paint should be supplied. As a result the possibility that the operator, for example a freely selectable maximum fill level in the paint tank can adjust before paint from the upper container 27 or is refilled from the tank 35. For this the valve 36 of the control unit 69 Tanks 35 opened, and the paint liquid can then via line 59 and inlet opening 74 to the filter 28 are directed, of which then the cleaned Paint liquid through the outlet opening 61 and the line 43 in the upper region of the container 31 is filled. This way the second Containers 31 each supplied cleaned paint liquid.

The time of filter replacement can also be changed determine by means of sensors 41, 42. Since with knowledge about the fill level of both containers 27 and 31 Return speed of the cleaned to be determined Liquid can be determined from the filter 28 the return quantity can also be a variable for control of the valves 34, 36, which are then closed must if the filter 28 with considerable contamination needs to be replaced. Due to the reduced return flow the filter 28 also becomes the container 31 not refilled so quickly, so this Time factor in connection with the fill level in the container 31 represents a manipulated variable on the basis of how already mentioned, the filter exchange described makes sense is.

The upper container 27 is also said to be advantageous Just a minimal amount of paint liquid so that only little paint liquid in the overall system is circulated continuously. This will ensures that there is no aging process in the paint liquid occurs because after a relatively short time the Most of the paint is used up before it is unused Paint from the tank 35 fed to the container 31 becomes. For this purpose, the control valve 36 is or control unit 69 opened and the paint overflows the filter 28 into the container 31 until the desired one reached the maximum filling level and the sensor 41 for automatic calibration with liquid is brought into contact. After that time the control valve 34 or 36 is automatically in again brought a closed position.

Due to the advantageous arrangement of the two in each leave a sensor 41, 42 arranged continuously measured values or resistance measured values determine and to the described evaluation unit 69 forward so that depending on the operating state individual valves 34, 36, 37, 51, 52, 30 simultaneously or can be controlled offset from one another in this way, the feed device 6 and thus also the containers already described 27, 31 to be supplied with paint liquid in good time.

The two sensors 41, 42 can be used as resistance sensors be trained.

It is also possible to have one in the area of the heater 39 Provide sensor for the paint temperature, so that this the heater 39 can be controlled accordingly can.

For example, the lower container 31 is not filled up accordingly, so the lower sensor 42 a corresponding manipulated variable to the evaluation unit 69 transmitted, via which the control valve 34, 36 can be opened.

3, 4 is the feed device 6 to apply the liquid or Lacquers 4 in the area of the painting head 49 or the substrate 2 shown. The feed device 6 is made from a horizontal with reference to Figures 3 and 4 Carrier 8, the one in the drawing not shown bracket or on a housing is arranged. The bracket 8 has an approximately box-shaped, formed from side parts 76 'to 76' '' ' Housing in which a drive device 3 with a stepper motor 9 for driving a transmission or rack or worm screw gear 15 is provided. The stepper motor 9 thus drives over that Gear 15, the feed device 6, so that this can be adjusted parallel to the surface of the substrate 2 can.

The support device 8 consists of a reference on the support arm 8 vertically extending part with a holder 68 provided at the upper end for receiving a supply line 17, at the upper end of which Nozzle 5 is connected so that the paint 4 can be delivered to the substrate 2. The supply line 17 is via lines 47, the heater 39 and the line 46 and the pump 29 to the lower container 31 connected.

As can be seen in particular from FIG. 3, the feed device 6 in the carrying device 8 between one extreme right and extreme left position in adjustable horizontal and vertical height.

So that a horizontal and vertical adjustment of the Feed device 6 is possible, the carrying device 8 a first link guide 7, which consists of a horizontally extending part 11, an adjoining, inclined part 12 and a in turn, also horizontally extending part 13 is formed for inclusion serve of sliding elements or roller bearings 10. is the feed device 6 in the position according to Figure 3, it has its lower position or position ingested, in which the nozzle 5 paint to the substrate 2 can deliver. The paint application via the nozzle 5 begins on the inside diameter of the substrate 2, so that by the rotational movement of the substrate carrier 14 medium dispensed onto the substrate 2 with the nozzle 5 or the paint evenly distributed outwards and the The rest is caught over the painting head 49. The horizontal extending part 11 of the guide 7 is advantageously as large as the corresponding one Painting radius of different substrate shapes, see above that there is a possibility with anyone Diameter to coat the substrate without varnish that when adjusting the feed device 6 the distance between the lower end of the nozzle 5 and the surface of the substrate 2 is changed. That way the drop height of the paint emerging from the nozzle 5 is constant kept and ensured that a even paint application.

The lower, horizontally running part 13 of the link guide 7 also ensures that the Stepper motor 9 an exact positioning of the nozzle 5 any place above the substrate 2 possible regardless of where the paint is applied on the surface of the substrate 2. Becomes the feed device 6 over the inclined Part 12 moved into the horizontally extending part 11, so the feed device 6 first leads a horizontal and then a horizontal-vertical, then again a horizontal movement. In this setting process becomes the reference position by means of a sensor 67 detected.

In the two connected to the feed device 6 Sliding elements or roller bearings 10, which in the first backdrop guide 7 are included, two others at a distance from the first roller bearings Roller bearings 10 'are provided, which in a further backdrop guide 7 'are added. The scenery guide 7 'runs parallel to part 11, 13 of the Setting guide 7 and ensures that a tilting of the Feeder 6 is avoided. So will that Stepper motor 9 is driven by a spindle and an associated link or nut 70 the feed device 6 either moved to the right or to the left.

This prevents damage to the supply line 17 is, this is by corresponding in the Feed device 6 provided holes or one Free space led.

Since all essential components, especially the drive device 3, a large part of the feeder 6 and the supply line 17, in the carrying device 8 are housed, these are not only from damage, but also from contamination Paint protected.

As can be seen in particular from FIG. 1, as already mentioned described, the output from the substrate carrier 14, liquid medium or the paint 4 over guide elements 19, 20 at least to the first container 27 are emitted with at least one filter 28 from which the liquid is directly or indirectly via a pump 29 to the first container 27 is passed, between the first drain line 33 of the first container 27 and the Pump 29 a negative pressure via a Venturi nozzle Pump 30 is adjustable.

The vacuum pump 30 is connected to a return device 32 connected from lines 33, 59 and 39 and the filter 28. The vacuum pump 30 protrudes a line 44 with the second container 31 in Connection. The spun off from the substrate carrier 14 Liquid or the liquid paint medium is over the first container 27 passed to the first filter 28, the return device 32 to the vacuum device or the venturi tube 44 is connected via which the negative pressure is generated becomes. This also allows liquid medium or Move high viscosity paint through the filter system and the desired purity for the liquid achieve trouble-free production operations. Due to the vacuum operation can also filter 28 with very fine mesh Filter elements 28 are used without this the throughput time of the lacquer in the entire device is adversely affected. Because of the advantageous Such filters can be used for the vacuum operation 28 can also remain in use much longer because next to the pump 29 in connection with the vacuum a high flow rate of the coating liquid is ensured.

In the exemplary embodiment, the Venturi tube or Vacuum pump 30 connected to the collecting container 31. Vacuum pump 30 may be any other suitable one Place between the first container 27 and the pump or metering pump 29 can be connected. The Metering pump 29 is via a control valve 73 of the feedback device 32 can be activated.

Claims (16)

1. A device for surface coating or for lacquering of substrates or disk-shaped substrates (2) such as a disk-shaped information carrier on a substrate carrier (14), wherein the liquid medium or the lacquering fluid (4) to be applied to the substrate (2) is placed on the substrate (2) by means of a feed device (6); liquid medium or lacquer (4) expelled from the substrate (2) is conveyed at least to a first reservoir (27) being connected with at least one filter (28) from which the liquid is indirectly or directly conveyed via a pump (29) to a second reservoir and/or again back to the first reservoir (27); characterized in that a vacuum pump (30) is integrated in or connected to the device in the liquid circuit between a first flow-off line (33) of the first reservoir (27) and a second reservoir (31) or/and the pump (29).
2. The device according to claim 1, wherein the substrate carrier (14) can be given a rotating movement by means of a drive device (3).
3. The device according to claim 1 or 2, wherein the second reservoir (31) for receiving the liquid medium (4) is connected between the filter (28) and the pump (29), and the vacuum pump (30) is connected to a return flow device (32).
4. The device according to one or a plurality of the previous claims, wherein the vacuum pump (30) is connected to the second reservoir (31) for receiving the liquid medium (4).
5. The device according to claim 4, wherein the vacuum pump (30) is embodied as a Venturi nozzle.
6. The device according to one or a plurality of the previous claims, wherein the first reservoir (27) is connected to the filter (28) via a liquid line (33) and a first valve (34) interrupting the liquid flow to the filter (28).
7. The device according to one or a plurality of the previous claims, wherein the first reservoir (27) is connected to the filter (28) via a liquid line (33, 59) and a first valve (34), and the filter (28) can be connected with the tank (35) via a second valve (36).
8. The device according to one or a plurality of the preceding claims, wherein a stop valve (37) is provided between the filter (28) and the second reservoir (31).
9. The device according to one or a plurality of the preceding claims, wherein a check valve (38) is provided between the second reservoir (31) and the pump (29).
10. The device according to one or a plurality of the preceding claims, wherein the liquid medium or the lacquer (4) supplied via the pump (29) is connected via a heater (39) to a nozzle (5) of the feed device (6).
11. The device according to one or a plurality of the preceding claims, wherein the substrate (2) or the substrate support (14) can be displaced by means of a guide means or in a connecting link guide (7) in such a way that in the area of the substrate (2) the feed device (6) for applying the liquid medium or the lacquer (4) is guided approximately parallel with the surface of the substrate (2) and can be stopped at any arbitrary point above the substrate (2).
12. The device according to one or a plurality of the preceding claims, wherein the feed device (6) is connected with the drive device (3) and supported by a support device (8).
13. The device according to claim 11 or 12, wherein the feed device (6) can be adjusted in the horizontal and/or vertical directions by means of the guide means (7).
14. The device according to one or a plurality of the preceding claims, wherein the drive device (3) is drivably connected with a step motor (9).
15. The device according to claim 14, wherein an electric or electro-hydraulic step motor (9) is provided.
16. The device according to claim 14 or 15, wherein the step motor (9) is drivably connected via a gear or a toothed rack or worm gear (15) with the guide device (7).

Images