WO2007062736A2

WO2007062736A2 - Ink dosing device

Info

Publication number: WO2007062736A2
Application number: PCT/EP2006/010792
Authority: WO
Inventors: Jörg Dantlgraber
Original assignee: Bosch Rexroth Ag
Priority date: 2005-12-02
Filing date: 2006-11-10
Publication date: 2007-06-07
Also published as: DE102005057752A1; WO2007062736A3

Abstract

Disclosed is an ink dosing device (1) for an ink application unit (6), in which a pulsed valve (28, 36) is provided between a displacement chamber (14) and an ink application unit (6). A predetermined amount of ink can be conveyed from the displacement chamber (14) to the ink application unit by specifically influencing the pulse/pause ratio when the pulsed valve (28, 36) is triggered.

Description

description

ink metering

The invention relates to a Farbdosiereinrichtung for a Farbauftrageinrichtung.

From DE 195 05 625 C2 an inking device for an offset printing machine is known. The inking device has a plurality of inking rollers, by means of which ink is applied to a pressure roller formed as a blanket cylinder. This patent specification does not give any information about the manner of application of the paint.

The patent application DE 10 2005 019 268.8 discloses an inking device for a printing roller, which can be arranged to save space over the printing roller. For this purpose, a plunger pump is provided which has a displaceable in a cylinder piston defining a displacement chamber in the cylinder. The displacement chamber communicates with the tank via a tank line and with the paint application nozzle via a pressure line. In the tank line, a suction valve and a metering valve is provided in the pressure line, so that when a displacement of the piston color from the tank in the displacement chamber is sucked, or color from the displacement chamber can be conveyed to the nozzle. About the control of the plunger piston actuating linear motor, both the delivery pressure and the delivery rate of the color is set. Depending on the pressure conditions in front of and behind the suction valve or the metering valve, these are opened and closed. It has been found that the color metering with such a device can be improved, among other things, also due to the pulsation in the promotion of the color.

The object of the present invention is to provide a paint metering device for an inking device, in which the disadvantages of the prior art are eliminated and with which an accurate color metering is possible, as well as to provide a valve for such a Farbauftrageinrichtung.

This object is achieved in terms of the ink metering device for a Farbauftrageinrichtung with the features of claim 1 and in terms of the valve with the features of claim 13. The ink dosing device according to the invention for an inking device has a displacement chamber and at least one cycled valve for color dosing, which is provided between the displacement chamber and the ink application device. Due to the use of a clocked valve, the removal of a desired amount of color from the displacement chamber and thus an accurate color dosage is possible.

Such a paint metering device may comprise a displacement device, a displacement measuring device and a control device. In this case, the displacement device limits the variable displacement space, the displacement measuring device detects the speed of the displacement device and the control device reproduces the pulse / pause ratio at the valve as a function of the speed which is detected on the basis of the measurement data of the displacement measuring device.

This controlled displacement device allows the constant delivery of a desired amount of ink and allows even in changing environmental conditions, such as. with changing temperature and changing air pressure, as well as for colors with different viscosity, an accurate color dosage.

According to one embodiment of the invention, the displacement device is a metering piston, which allows a precise control of the amount of ink due to its substantially constant effective area on the distance measurement.

Particularly advantageous is the hydraulic drive of the dosing with color as pressure medium so that a further mechanical means or another pressure means for returning the piston to its initial position is not necessary.

Preferably, the metering piston is double-acting, so that a color promotion can be carried out in both directions of movement with piston movement.

The double-acting metering piston can have two effective surfaces each defining a displacement space with different area contents. The differences in the delivery volumes resulting from the different surface contents can be compensated by an adapted clocking of the clocked valves assigned to the displacement chambers. Thus, the mechanical differences of the active surfaces on the piston can be compensated by an electrical control of the valves.

According to a further embodiment of the invention, the displacement device is a membrane. A membrane is especially in the presence only a displacement space of advantage, since this is reset with low mechanical forces in their initial position.

In the present invention, the displacement space can be filled with a paint pump, so that the pressure of the ink and the amount of ink can be accurately adjusted.

The at least one clocked valve is preferably leak-free, so that losses in color during operation can be reduced and the maintenance costs can be reduced.

The timed valve may have a seal for sealing off an electromagnet used to actuate the timed valve against color, so that changes in the amount of ink delivered due to paint residues on the electromagnet can be avoided.

The present invention also discloses a valve for one of the paint dosing devices described above, which is designed as a leak-free seat valve. Thus, low manufacturing costs for a Farbdosiereinrichtung can be achieved.

The valve according to the invention may have a valve seal for sealing magnet armature and a valve plate of the valve, so that the penetration of paint between mechanically movable parts in the valve is prevented and the service life of the valves can be increased.

The valve seal is preferably a sealing ring, for example made of plastic, so that at low production costs, a good sealing effect can be achieved.

According to a modification of the invention, the valve seal of a plate spring which also ensures a good sealing effect at low production costs.

Further embodiments are the subject of the dependent claims.

In the following preferred embodiments of the invention will be explained in more detail with reference to schematic representations. Show it:

1 shows a paint metering device with pump, tank and paint applicator according to a first embodiment of the invention, FIG. 2 shows a paint metering device with pump, tank and paint applicator according to a second exemplary embodiment of an invention,

FIG. 3 shows the control behavior of the ink metering device according to the second exemplary embodiment,

FIG. 4 shows a clocked valve without seal for use in the ink metering device according to the first and second exemplary embodiments,

FIG. 5 shows a modification of the valve from FIG. 4 with a seal,

Figure 6 shows a further modification of the valve of Figure 4 with seal

Figure 7 shows a still further modification of the valve of Figure 4 with seal and

Fig. 8. a valve variant with solenoid plunger.

1 shows a Farbdosiereinrichtung 1 is shown according to the first exemplary embodiment, which consists essentially of a tank 2, a pump 4 and a Farbauftrageinrichtung 6.

The ink metering device 1 has a piston 10 movably mounted in a cylinder 8, which has an end face 12 at its one end section and an annular end face 16 at its other end section, which is bounded by a piston rod 20 extending away from the piston 10. The end face 12 defines a left displacement chamber 14 and the annular end face 16 defines a right-hand displacement chamber 18. The left-hand displacement chamber 14 is in fluid communication with the pump 4 via a left-hand suction line 22. In the left suction line 22, a left suction valve 24 is provided so that sucked from the tank 2 by the pump 4 sucked paint on the left suction line 22 ^■ and the left suction valve 24 in the left displacement chamber 14.

From the left suction line 22 branches off a right suction line 30, in which a right suction valve 32 is provided and which communicates with the right-hand displacement chamber 18 in fluid communication. The left displacement chamber 14 is connected via a left pressure line 26, in which a left metering valve 28 is provided with a Farbauftrageinrichtung 6 in fluid communication. The right-hand displacement chamber 18 can be connected to the paint application device 6 via a right-hand metering valve 36 provided in a right-hand pressure line 34. The left metering line 28 and the right metering line 34 open into the common input connection of the paint application device 6.

On the piston rod 20, a path measuring device 38 shown schematically in Figure 1 is provided whose measured variables are input variables of a control amplifier 40. The left suction valve 24, the left metering valve 28, the right suction valve 32 and the right metering valve 36 are in the circuit diagram shown in Figure 1 2/2-way valves with solenoid actuation. Preferably, the basic position is defined in each case by a spring, not shown. The electromagnets of these valves 24, 28, 32, 36 are controlled by the control amplifier 40, so that the valves 24, 28, 32 and 36 are controllable in dependence on the data recorded by the path measuring device 38.

All valves are biased in their normal position to the closed position. An actuation of the electromagnet e.g. causes the valves 24, 36 through the control amplifier 40 that they reach their open switching position.

Thus, ink conveyed by the pump flows into the space 14, and from the space 18 color is conveyed into the paint applicator 6.

The left suction valve 24 and the left metering valve 28 are controlled substantially in such a manner that when one of the valves is in the closed switching position, the other valve is in the open switching position, so that a pressure medium connection either from the pump 4 to left displacement chamber 14 or from the left displacement chamber 14 to the paint applicator 6 consists. The control of the right suction valve 32 and the right metering valve 36 takes place in coordination with the control of the valves 24 and 28, so that at a pressure fluid connection from the pump 4 via the right suction valve 32 to the right displacement chamber 18 also a pressure medium connection from the left displacement chamber 14 via the left metering valve 28 to Farbauftrageinrichtung 6 exists. In the case of a pressure medium connection from the pump 4 via the left suction valve 24 to the left displacement chamber 14, there is likewise a pressure medium connection from the right displacement chamber 18 via the right metering valve 36 to the paint application device 6.

The present invention is not limited to the aforesaid type of valve, but any tactile valve may be used in a paint metering device according to the present invention.

The operation of the ink metering device of the first embodiment will be described below.

It is assumed that the valves 24, 28, 32 and 36 are in the respective switching position shown in Figure 1, ie the left suction valve 24 and the right metering valve 36 are open and the right suction valve 32 and the left metering valve 28 in the closed Switch position are. Thus passes through the pump 4 from the tank. 2 Promoted paint on the left suction line 22 and the open left suction valve 24 in the left displacement chamber fourteenth

The pressure building up in the left-hand displacement chamber 14 acts on the end face 12 and causes a movement of the piston 10 in the cylinder 8 in FIG. 1 to the right. This reduces the volume of the right-hand displacement chamber 18. The paint conveyed from the previous operation of the ink metering device into the right-hand displacement chamber 18 passes via the open right-hand metering valve 36 and the right-hand pressure line 34 to the ink application device 6. This is, for example, a roller or a nozzle. over which the color can be applied to a desired location.

Depending on the distance measured by the path measuring device 38, the electromagnets of the valves 24, 28, 32 and 36 are now actuated in such a way that the left metering valve 28 and the right suction valve 32 reach the open switching position and the left suction valve 24 and the right metering valve 36 in the closed switching position and the right metering valve 36 reach the closed switching position. Thus, the conveyed from the tank 2 via the pump 4 and the right suction line 30 color passes through the open right suction valve 32 into the right displacement chamber 18. The pressure in the right displacement chamber 18 acts on the annular end face 16 and causes movement of the piston 10 in the cylinder eighth in Figure 1 to the left, so that the volume of the left displacement chamber 14 is reduced. The color present in the left-hand displacement chamber 14 is conveyed via the left-hand metering valve 28 and the left-hand pressure line 26 to the paint applicator 6.

In this way, both during a movement of the piston 10 in Figure 1 to the right and during a movement of the piston 10 in Figure 1 to the left to promote color from the pump 4 to the ink application device 6.

Figure 2 shows a Farbdosiereinrichtung 48 according to the second embodiment. In the ink metering device, a diaphragm 50 is used instead of the piston 10 of the first embodiment. With the diaphragm 50, the piston rod 20 is connected in the cylinder 54. Around the piston rod 20 around a return spring 52 is provided, which is supported at one end portion on the cylinder 54 and the opposite end portion is supported on the membrane.

The membrane 14 divides the space in the cylinder in a displacement chamber 14 and a spring chamber 19. In contrast to the first embodiment is instead of the right Displacement chamber 18 from the first exemplary embodiment, a spring chamber 19 is provided, which is relieved to the environment. When the suction valve 24 is open pressure medium is required by the pump 4 via the suction line 22 in the displacement chamber 14 and a bulging of the membrane 50 is effected to the Eederraum 19 out. A conveying of the pressure medium present in the displacement chamber 14 in Fig. 2 to the right-curved membrane 50 is carried out with the metering valve 28 open to the ink application device 6 back.

As in the first embodiment, a displacement measuring device 38 is provided on the piston rod 20, which is electrically connected to a variable gain amplifier 40.

Color can get from the tank 2 via the pump 4 and the suction line 22 and a suction valve 24 in the displacement chamber 14 and from this via a pressure line 6, in which a metering valve 28 is provided, reach the paint applicator 6. For the valves 24 and 28, the same valves can be used as in the first embodiment, the execution of which reference is made here.

The suction valve 24 and the metering valve 28 have electromagnets which are electrically controlled by the variable gain amplifier 40.

Hereinafter, the operation of the ink metering device 48 according to the second embodiment will be described with reference to FIG. In Figure 3, the opening state of the metering valve 28 and the required volume of color over time are shown.

At the beginning of operation, it is assumed that the paint dosing device 48 is in the switching position shown in Figure 2, i. the suction valve 24 is open and the metering valve 28 is closed. The pump 4 requests paint from the tank 2 via the suction line 22 and the suction valve 24 in the displacement chamber 14. The pressure in the displacement chamber 14 increases and causes a deformation of the diaphragm 50 against the force of the return spring 52 and a movement of the piston rod 20 in FIG 2 to the right. This movement is detected by the path measuring device 38.

In response to the shifted path of the piston rod 20, the control amplifier 40 switches the electromagnets of the valves 24, 28, so that after a predetermined backward path of the piston rod 20, the suction valve 24 enters the closed switching position and the metering valve 28 enters the open switching position. Now, due to the force of the return spring 52, a movement of the membrane 50th 2 causes to the left, so the pressure medium from the displacement chamber 14 via the pressure line 26 and the metering valve 28 is conveyed to the ink application device.

The time-increasing volume of the conveyed color is shown in Figure 3 by the rise of the curve up to the time t \. Depending on the

Measurement of the displacement measuring device 38 is then shown in Figure 3 by the time t ^, the control amplifier 40 bring the suction valve 24 in the open switching position and the metering valve 28 in the closed switching position, so that in Figure 3 at time t ^ to time t2 no further ink from the displacement chamber 14 passes into the ink application device 6 until at time t2 the suction valve 24 is closed and the metering valve 28 is opened.

From time t2 to time tβ, ink from the displacement space 14 enters the ink applicator 6, so that the volume of ink in the ink applicator 6 increases. In the case of the ink metering device 48 according to the second exemplary embodiment, there is thus a discontinuous delivery of the ink to the ink application device 6 with slight pulsation.

Due to the smaller number of hydraulic components used, the costs for a Farbdosiereinrichtung 48 according to the second embodiment are lower than in the first embodiment.

A 2/2-seat valve usable in the ink metering device 1, 48 according to the first and second embodiments is shown in FIG.

The seat valve has a valve housing 58 which limits a pressure chamber 60. Into the valve housing opposite to an inlet 62 with an inlet opening 64, a magnetic core 68 is inserted, in which a coil 70 is located. On the magnetic core 68 is supported by a return spring 74, an anchor plate 72, with the inlet port 64 is closed. Branching off radially from the pressure chamber 60 is an outlet 66.

FIG. 4 shows the opened state of the directional valve, in which the armature plate 72 is attracted by the current-carrying coil 70 against the force of the return spring 74, so that pressure medium can flow via the inlet 62 and the inlet opening 64 and through the pressure chamber 60 to the outlet 66. When energized coil 70, the armature plate 72 is pressed via the return spring 74 to the inlet port 64 so that between the inlet 62 and the outlet 66 no pressure medium connection exists.

FIG. 5 shows a variant of the valve from FIG. 4, in which a space defined between the magnetic core 68 and the coil, on the one hand, and the armature plate 72, on the other hand, is sealed via a spring device arranged radially outside the magnetic core 68, which is represented as a plate spring 82 in FIG becomes.

Furthermore, an inlet ring 80, which is curved in the direction of the magnetic core 68, is provided around the inlet opening 64 facing the pressure chamber 60, by means of which the contact surface between the anchor plate 72 and the part encompassing the inlet opening 64 is reduced, so that a better sealing effect can be achieved.

Between armature plate 72 and coil 70, a filling material 84 is further provided of non-magnetic material, such as aluminum or magnesium, which protrudes annularly beyond the end face of the magnetic core 68. Due to the smaller contact surface of the armature plate 72 with the magnetic core 68, a faster switching behavior can be achieved.

The plate spring 82, which seals between anchor plate 72 and magnetic core 68, prevents the penetration of paint and thus the solid drying of this in the pressure chamber 60, so that a blocking of the valves can be prevented.

FIGS. 6 and 7 show further variants of the sealing device between the armature plate 72 and the magnetic core 68.

In the variant according to FIG. 6, a sealing ring 90 made of plastic is provided between the armature plate 72 and the magnetic core 68, said sealing ring resting firmly against the armature plate 72 on the one hand and the magnetic core 90 on the other hand. The material for the sealing ring 90 is not limited to plastic but any elastic material for the sealing ring 90 can be used. Due to the elasticity of the sealing ring 90 this has both Abdichtwir-kung and the effect of the return spring 74 shown in Figure 4.

In Figure 7, between the magnetic core 68 and the armature plate 72 both the return spring 64, as well as radially outside of this a sealing bar 100, for example made of rubber, is provided. By the return spring 74, the armature plate 72 is pushed away from the magnetic core 68, while the sealing bar ensures a seal between the magnetic core 68 and anchor plate 72. In one embodiment of the valves 24, 28, 32 and 36 as shown in Figures 4 to 7, can promote a certain amount of color at low Ansprechverzöger-ung and suitable pulse / pause behavior of the valves.

The valves 24, 28, 32 and 36 are not limited to the illustrated embodiment, but may for example be proportionally adjustable.

Disclosed is thus a Farbdosiereinrichtung for a Farbauftrageinrichtung, in which a clocked valve is provided for color metering between a displacement chamber and a Farbauftrageinrichtung. By selectively influencing the PuIs- / pause ratio in the control of the clocked valve can be a predetermined amount of color from the displacement space to promote Farbauftrageinrichtung.

Fig. 8 shows a valve in which instead of a flat armature magnet, a solenoid plunger is used. The anchor plate 72 (FIG. 4) is here replaced by a round anchor 73. The seal 90, which represents the spring / sealing element is designed so that the decrease in volume is compensated when tightening the round anchor 73 by bulging the sealing ring to the outside.

LIST OF REFERENCE NUMBERS

1 paint dosing device

tank

pump

Inking device

cylinder

10 pistons

12 face

14 left displacement space

16 ring end face

18 right displacement space

19 spring chamber 0 piston rod. 2 left suction line 4 left suction valve 6 left pressure line 8 left dosing valve 0 right suction line 2 right suction valve 4 right pressure line 6 right dosing valve 8 displacement measuring device 0 control amplifier 8 paint dosing device 0 diaphragm 2 return spring 4 cylinder 8 valve housing 0 pressure chamber 2 inlet 4 inlet opening 6 outlet 8 magnetic core 0 coil 2 anchor plate 3 round anchor 4 return spring 80 inlet ring

82 plate spring

84 filling material

90 sealing ring

100 sealing bellows

Claims

claims

1. Farbdosiereinrichtung (1) for a Farbauftrageinrichtung (6) with a displacement chamber (14) and at least one between the displacement chamber (14) and Farbauftrageinrichtung (6) arranged, clocked valve (28) for color metering.

2. ink metering device according to claim 1 with a variable displacement chamber (14) limiting displacement means (10, 50) connected to the displacement means Wegmeßeinrichtung (38) for detecting the speed of the displacement means (10, 50) and a control device (40) for setting the pulse / pause ratio at the valve (28) in dependence on the detected by the path measuring device (38) speed.

3. ink metering device according to claim 1 or 2, wherein the displacement means comprises a metering piston (10).

4. ink metering device according to claim 3, wherein the metering piston (10) is hydraulically driven with ink as a pressure medium.

5. ink metering device according to claim 3 or 4, wherein the metering piston (10) is double-acting.

6. ink metering device according to one of claims 3 to 5, wherein the double-acting metering piston (10) has two, each a displacement space limiting active surfaces (12, 16).

7. Farbdosiereinrichtung according to claim 6 or 7, wherein each displacement chamber (14, 18) a suction valve (24; 32) and a metering valve (28, 36) are associated, which are controllable in such a way that the one of the two associated valves open and the other is closed.

8. ink metering device according to claim 1 or 2, wherein the displacement means comprises a membrane (50).

9. paint metering device according to one of the preceding claims, wherein the displacement chamber (14) with a paint pump (4) can be filled.

10.. Ink metering device according to one of the preceding claims, wherein the at least one clocked valve (28) is designed leak-free.

11.. A paint metering device according to any one of the preceding claims, wherein the at least one timed valve (28) comprises a seal (82, 90, 100) for sealing an electromagnet (68, 70) used to actuate the timed valve (28) against color.

12. Valve for a paint metering device according to one of the preceding claims, which is designed as a leaking low-way valve (28).

13. Valve according to claim 12 with a valve seal (82, 90, 100) for sealing between the magnetic core (68) and an armature plate (72) of the valve.

14. Valve according to claim 12 or 13, wherein the valve seal has a sealing ring (90), preferably made of plastic.

15. Valve according to claim 12 or 13, wherein the valve seal comprises a plate spring (82).

16. A valve according to claim 14, wherein the sealing ring 90 increases in deformation in the direction of higher bias its internal volume.