Doctor blade mechanism for a printing apparatus

Abstract

The invention relates to a squeegee mechanism (4) for a printing apparatus (2) for printing planar substrates, in particular circuit boards, wafers or solar cells, having two squeegee blades (5, 6) which extend parallel to one another and are pivotably mounted. According to the invention, the squeegee blades (5, 6) are operatively connected to a transmission (35) which is configured in a self-locking manner and is couplable or coupled to a drive device (22).

Description

Technical Field

[0001] The present invention relates to a squeegee mechanism for printing equipment for printing planar substrates, particularly circuit boards, wafers or solar cells, the squeegee mechanism having two squeegee blades that extend parallel to each other and are pivotally supported.

[0002] Furthermore, the present invention relates to a squeegee device for printing equipment, for printing planar substrates, particularly circuit boards, wafers or solar cells, the squeegee device having a squeegee mechanism and a drive device for driving the squeegee mechanism.

[0003] Furthermore, the present invention relates to a printing apparatus for printing planar substrates, particularly circuit boards, wafers, or solar cells, comprising a squeegee device, a screen holder on which a screen, a template, or a mask can be arranged, and a printing table on which the substrate to be printed can be arranged on the printing table on the side of the screen holder opposite to the squeegee device. Background Technology

[0004] The aforementioned type of printing equipment and squeegee mechanism is known from the prior art. For printing on planar substrates such as circuit boards or wafers, a squeegee mechanism is used, through which predetermined patterns, such as conductive circuits, can be printed in large quantities in a short time by means of a squeegee unit. For this purpose, a printing material is fed onto a printing screen or printing mask, which may, for example, be made of a conductive material, wherein the printing mask or printing screen has openings or gaps corresponding to the desired printed image. If the squeegee is then moved across the screen with one or more squeegee blades, the printing material is forced through the printing screen or printing mask or printing template in such a way that it is applied to the substrate. Squeegee mechanisms with two squeegee blades are known, which extend parallel to each other but are oriented at an angle to each other in opposite directions, such that one squeegee blade interacts with the printing material in a first direction during its movement, while the second squeegee blade interacts with the printing material in the opposite direction during the movement of the second squeegee blade.

[0005] To change the printing material, previously used printing material must be removed from the squeegee mechanism or the mechanism itself must be cleaned. This involves, for example, removing the squeegee blades and the printing screen or mask from the squeegee mechanism and cleaning them outside the printing equipment. During the removal and transport of the squeegee mechanism, any printing material remaining on the squeegee blades after the previous printing process may be lost. At the very least, during the cleaning process, the printing material will be lost due to further printing processes. Summary of the Invention

[0006] The object of the present invention is to provide an improved scraper mechanism, wherein the loss of printing material is reduced when changing the scraper mechanism or the printing material.

[0007] The objective of this invention is achieved through a squeegee mechanism. The squeegee mechanism according to the invention has the advantage that larger quantities of printed material can be safely stored or transported using the squeegee mechanism, especially even when the entire squeegee mechanism is detached from the printing equipment. The invention achieves that the printed material is safely held in the squeegee mechanism and can, for example, be purposefully provided for reuse. The invention also allows the squeegee mechanism to be transferred from one printing equipment to another, thereby transferring printed material, particularly solder paste, from one printing screen to another, i.e., the printing screen of another printing equipment. This saves the user material costs, avoids waste, and reduces the proportion of squeegee mechanisms that are recycled in production. If the squeegee mechanism can also be changed completely automatically, the level of automation in production will be even higher.

[0008] According to the invention, this is achieved by the following means: the squeegee blade is pivotally supported, particularly capable of reverse pivoting, so that the angle of the squeegee blade relative to the printing screen or printing mask can be set, and the squeegee mechanism is effectively connected to the conveying device, which is self-locking and can be coupled or connected to the drive device. Therefore, the squeegee angle can be set by means of the drive device via the conveying device. Since the squeegees are preferably also effectively connected to each other via the conveying device, the squeegee angles of two squeegee blades can be set simultaneously by the same conveying device and the same drive device. Due to the self-locking construction of the conveying device, the squeegee blade retains the previously set squeegee angle, especially even when the drive device is separated from the conveying device. Thus, the squeegee blade can be pivoted particularly to a conveying position, in which the printing material is optimally blocked or held in the squeegee mechanism, so that the squeegee mechanism can be replaced or transferred to the cleaning device without loss of printing material.

[0009] Particularly preferably, the squeegee blades are arranged on the squeegee frame in such a way that the drive mechanism allows the squeegee blades to pivot into a V-shaped position, in which the squeegee blades abut against each other at their free working edges. Here, the working edge of the squeegee is understood as the longitudinal edge of the squeegee blade, which is distributed to the printing screen or printing mask during operation and forces the printing material through the printing mask or printing screen. By pivoting to the V-shaped position, the squeegee blades together form a V-shaped space, which is closed at its apex by the abutment of the working edges of the squeegee. The printing material on the squeegee blades therefore cannot escape from this space in the working edge region of the squeegee. Thus, a type of printing material bag is formed in the squeegee mechanism by means of which the printing material can be safely contained for, for example, stencil changes, screen changes, or changes of the entire squeegee mechanism.

[0010] According to a preferred embodiment of the invention, the transmission device is constructed as a worm gear drive. This allows the self-locking of the transmission device to be achieved safely and cost-effectively in a simple and known manner. The worm gear drive enables the transmission of a high set force, ensuring high robustness against undesirable adjustments to the scraper angle.

[0011] Preferably, each scraper blade is arranged on a rotatably supported shaft for pivoting, wherein the worm gear of the turbine drive is torsionally arranged on each shaft, the turbine engaging with the worm shaft of the turbine drive which is connected to or can be connected to the drive device. Therefore, the scraper blades can be adjusted by means of the drive mechanism. However, when the screw shaft is not driven, adjustment of the scraper blades is prevented due to self-locking. The shaft is preferably integrally constructed in the respective scraper blade, such that the scraper blade itself is constructed as a corresponding shaft, for example, on its longitudinal side facing away from the working edge of the scraper, for this purpose, for example, a shaft head protruding at the end side of the respective scraper blade, which can be inserted into a bearing seat, for example, a bearing frame, for pivoting support. Therefore, it is also conceivable that the corresponding worm gear is integrally constructed with the corresponding scraper blade, and that there is generally no fully constructed worm gear, but rather a worm gear with a circumferential extension of less than 360°. According to an alternative embodiment of the invention, the corresponding scraper blade is pushed onto a continuous shaft and is either rotatably supported on the shaft, or the shaft is rotatably supported in a bearing seat, for example, a scraper frame. In this case, the worm gear is either torsionally connected to the scraper blade and / or torsionally connected to the shaft.

[0012] Furthermore, preferably, the transmission device has a drive shaft that is connected to the worm shaft on one side and has a coupling end on the other side, which is configured to detachably connect the drive shaft to the drive device. The drive shaft is connected to the worm shaft with particularly torsional resistance, such that the driving force, especially the driving torque, acting on the drive shaft is directly applied to the worm shaft to pivot the scraper blades. The coupling end allows the drive shaft to be detachably connected to the drive device. Therefore, the scraper mechanism can be advantageously disengaged from the drive device as a whole, wherein the self-locking mechanism of the transmission device functions due to the disengagement, and it itself prevents further adjustment between the scraper blades. The coupling end further ensures a simple connection or effective linkage between the scraper mechanism and the drive device.

[0013] Particularly preferably, the connecting end is constructed as a detachable coupling with friction locking or form locking, particularly as a friction coupling or claw coupling. Because of the friction coupling or claw coupling, a simple connection between the connecting end and the drive device is ensured, and the drive device preferably also has a shaft with a component having a friction coupling, claw coupling, or friction locking or form locking coupling.

[0014] According to a preferred extended configuration of the invention, the scraper mechanism has a housing in which a transmission device, a scraper support, and scraper blades are held, or on, the scraper mechanism, wherein a drive shaft is guided outward through an opening in the housing. On the one hand, the housing protects the components of the scraper mechanism arranged within it, such as the transmission device, scraper support, and scraper blades, from external influences. The drive shaft protruding from the housing ensures easy connection to the drive device. Furthermore, on the other hand, the user can also manually operate the drive shaft protruding from the housing to change the position of the scraper blades as needed, for example, for cleaning purposes. Therefore, the scraper mechanism can be operated, for example, manually by the user outside the printing equipment or automatically by a cleaning machine, to open the receiving bag formed by the scraper blades and release the printing material contained therein.

[0015] According to a preferred extended configuration of the invention, the squeegee mechanism has a means for detachably securing it to the drive unit. Thus, by means of this means, the squeegee mechanism can be detachably secured to the drive unit, thereby allowing for easy replacement of the squeegee mechanism on the printing equipment or on the drive unit. Consequently, the entire squeegee mechanism can be easily detached from the drive unit and, for example, transferred to another printing equipment having a corresponding drive unit, and connected thereto to perform further printing processes on that other printing equipment. The squeegee can also be separated from the drive unit and correspondingly from the printing equipment for use with the cleaning unit. The means for detachable securing is understood to specifically allow the squeegee mechanism to be detached from or secured to the drive unit, particularly without tools, using several manual operations. In this document, the threaded connection that allows the squeegee mechanism to be secured to the drive unit by fixing screws is not understood as a means for detachable securing, but rather as a permanent securing means.

[0016] Particularly preferably, the device is configured as a locking device. Therefore, the scraper mechanism can be locked to the drive device in a form-locking manner. The locking device preferably has one or more resiliently displaceable locking elements that can be repositioned under elastic deformation to a position that holds the scraper mechanism in a form-locking manner on the drive device. Preferably, the device also has, for example, recesses or notches constructed in the housing or drive device to interact in a form-locking manner with the respective resiliently movable locking elements of the drive device or housing. Therefore, corresponding resiliently movable or deformable locking elements can be arranged on the scraper mechanism itself or on the drive device. Thus, recesses or notches are constructed or arranged at corresponding other devices.

[0017] According to a preferred extended configuration of the invention, the scraper mechanism has a drive unit having at least one drive mechanism, particularly an electric motor, which can be coupled or connected to a transmission device, particularly a drive shaft of a transmission system. The drive unit is, in particular, the aforementioned drive unit, and the remaining scraper mechanism can be detachably connected to this drive unit. Optionally, the drive unit is integrated into a printing apparatus, which in particular also has a printing table on which the substrate to be printed can be arranged.

[0018] The drive machine preferably has an output shaft with an end that is coupled to or connectable to a transmission device. The end of the output shaft can thus be detachably connected to the coupling end of the drive shaft. In particular, the coupling end and the end together are configured as a coupling that operates in a form-locking manner or a friction-locking manner, especially a claw coupling or a friction coupling.

[0019] Specifically, the scraper mechanism can be detachably connected to or can be connected to the drive unit. Specifically, the drive unit and / or scraper mechanism have the aforementioned means for easy engagement and disengagement of the scraper mechanism and the drive unit, ensuring easy replacement of the scraper mechanism. Specifically, as described above, the means is configured as a locking device.

[0020] Particularly preferably, the drive unit has a scraper mechanism retainer that can be detachably connected to the scraper mechanism. Specifically, the scraper mechanism retainer includes means or part of means for detachably securing the scraper mechanism, such that the scraper mechanism can be detachably secured or can be secured to the frame retainer. Therefore, the scraper mechanism retainer serves as the interface between the scraper mechanism and the drive unit, and is used to accommodate and support the scraper mechanism. The detachable connection is designed particularly as described above, especially with at least one elastically deformable or displaceable locking element.

[0021] The squeegee mechanism holder is preferably pivotally supported about a central axis parallel to the axial orientation of the squeegee mechanism. By pivoting the squeegee mechanism holder about the central axis, the squeegee mechanism fixed to the holder is also pivoted, allowing the squeegee mechanism to optimally align in its orientation with the printing process. Specifically, the squeegee mechanism holder pivots in one or the other direction depending on the direction of squeegee movement to achieve optimal squeegee effect.

[0022] Particularly preferably, the squeegee mechanism retainer has a controllable actuator at at least one protrusion remote from the central axis for pivoting the squeegee mechanism retainer. Therefore, the squeegee mechanism retainer can be influenced or set in its pivoting position by the actuator to achieve precise printing results. Optionally, the squeegee mechanism retainer has protrusions arranged remotely on both sides of the central axis, each protrusion having a controllable actuator.

[0023] Particularly preferably, the actuator is configured as a pneumatic actuator with a lifting piston assigned to the protrusion, the lifting piston acting tangentially to the protrusion, particularly about the central axis. By configuring the actuator as a pneumatic actuator, the actuator gains elasticity due to the compressible pneumatic medium. This ensures that, in the event of excessive resistance when moving the scraper blades, the scraper mechanism can pivot or move against the force of the actuator, thereby safely avoiding damage to the scraper blades. Therefore, the pneumatic actuator acts as a preload on the scraper frame. In particular, the entire scraper mechanism can pivotally shift against the preload force of the actuator.

[0024] The printing apparatus of the present invention is characterized by a squeegee arrangement constructed according to the invention. In particular, using the above-described arrangement, the squeegee mechanism can be interchangeably fixed or can be fixed to a drive device. The squeegee mechanism, together with the squeegee device, is particularly configured as the print head of a printing apparatus. Preferably, a printing system is also provided, wherein multiple printing devices are provided, each having a drive device, to which the squeegee mechanism according to the invention can be fixed. Attached Figure Description

[0025] The invention will be explained in more detail below with reference to the accompanying drawings. The drawings show:

[0026] Figure 1 A simplified side view of an advantageous scraper device for printing equipment;

[0027] Figure 2 Top view of the scraper device;

[0028] Figure 3 Detailed view of the scraper device;

[0029] Figures 4A to 4C Different views of the lifting equipment of the scraper device. Detailed Implementation

[0030] Figure 1 A simplified side view shows an advantageous squeegee device 1 for printing on a planar substrate, particularly printed circuit boards, wafers, etc., using a printing apparatus 2 (not shown in detail here). The squeegee device 1 is configured to force the printing material through openings or structures of a printing screen 3, which only... Figure 1 The image is schematically shown, and thus applied to one or more substrates located below the printing screen 3.

[0031] Therefore, the scraper device 1 has a scraper mechanism 4, which carries two scraper blades 5 and 6. Figure 1 In the image, squeegees 5 and 6 extend perpendicular to the image plane, with squeegee blades 5 and 6 held on the squeegee support 9 of the squeegee mechanism 4 at their longitudinal edges, and forming squeegee working edges 7 and 8 at their opposite longitudinal edges, which are used for brushing the printing material or printing screen 3. Squeegee blades 5 and 6 can be made of metal or plastic and are constructed to be rigid or slightly elastically deformable.

[0032] Figure 2A simplified top view of the scraper mechanism 4 is shown. The scraper mechanism 4 has a scraper support 9 on which scraper blades 5 and 6 are pivotally supported. For this purpose, the scraper blades 5 and 6 are respectively connected to or torsionally fixed to shafts 10 and 11 at their ends opposite to the working edges 7 and 8 of the scraper, such that rotation of the corresponding shafts 11 and 10 results in a corresponding adjustment of the scraper angle α5 or α6 of the corresponding scraper blades 5 and 6. Figure 1 As shown. Shafts 10 and 11 have, for example, radial grooves in which scraper blades 5 and 6 are inserted and held.

[0033] like Figure 2 As shown, shafts 10 and 11 are advantageously rotatably supported by a plurality of rolling element bearings 12, thus minimizing frictional losses during torsion. Optionally, the squeegee blades 5 and 6 have corresponding paste limiters 13 at their ends, which prevent printing paste applied during the brushing of the printing screen 3 from overflowing from the sides via the squeegees 5 and 6.

[0034] Shafts 10 and 11 each carry worm gears 14 and 15, which are torsionally connected to the corresponding shafts 10 and 11. Specifically, the worm gears 14 and 15 are centrally arranged on shafts 10 and 11 (viewed in the longitudinal extension direction of shafts 10 and 11), such as... Figure 2 As shown. Worm gears 14 and 15 are therefore parallel to each other. A worm shaft 16 is arranged between the worm gears 14 and 15, which meshes or engages with the two worm gears 14 and 15. The worm shaft 16 is rotatably supported on the scraper support 9 by another rolling element bearing 12. The worm shaft 16 also passes through the drive shaft 17, and is therefore integrally constructed with the drive shaft 17, which passes through the housing 18 arranged at the scraper support 9 in the region of the rolling element bearing and protrudes outward from the housing 18. Optionally, the scraper support 9 constitutes the housing 18. The housing 18 is constructed in a basin shape, as shown. Figure 1 As exemplarily shown, the drive shaft 17 passes through the basin-shaped bottom and at least surrounds the shafts 10, 11 and the worm gears 14, 15, thereby protecting them from external influences. The housing 18 is constructed open at its end opposite the drive shaft 17, allowing the scraper blades 5, 6 to exit from the housing 18 and pivot, as shown. Figure 1 As shown.

[0035] The drive shaft 17 has a connecting end 19 at its end opposite to the worm shaft 16. The connecting end 19 is characterized by having an outer diameter that increases with the distance from the worm shaft 16, and a recess 20 on its free end side, such that the connecting end 19 is constructed as a hollow shaft that expands in a V-shape when viewed in longitudinal section. This results in a funnel shape for the connecting end 19. Advantageously, the connecting end 19 has a synchronizing structure on its inner side 21, for example, in the form of a groove, recess, protrusion, or tooth. According to an alternative embodiment, the drive shaft 17 has a recess 20 but does not expand on its outer side, thus constructing a particularly V-shaped recess 20 on the end side and retaining the outer wall of the shaft in the region of the connecting end 19 as cylindrical.

[0036] The scraper device 1 also has a drive unit 22, which is arranged above the scraper mechanism 4, such as... Figure 1 As shown. The drive unit 22 has, for example, an electric motor 23, which is directly or via a transmission device connected to the output shaft 24. The output shaft 24 extends from the housing of the electric motor 23 toward the scraper mechanism 4 and has an end 25 for detachably connecting to the connecting end 19 of the scraper mechanism 4. For this purpose, the end 25 is preferably configured to complement the connecting end 19, and according to this embodiment, is configured as a tapered post whose cone angle approximately corresponds to the opening angle of the V-shaped connecting end 19, preferably with a slightly smaller cone angle. Thus, the connecting end 19 can be easily pushed onto the end 25 of the output shaft 24. In particular, the connecting end 19 and the end 25 are configured together as a detachable connector 26. In particular, the connector 26 is configured as a friction connector. Alternatively, the connector 26 is configured as a claw connector or a form-locking connector. For this purpose, grooves, teeth, or recesses optionally constructed on the inner side 21 are particularly used to engage with corresponding protrusions, grooves, recesses, or teeth of the end 25. This ensures torque transmission through the form-locking mechanism from the drive unit 22 to the worm shaft 16.

[0037] According to another embodiment, the recess 20 is formed in the end portion 25, and the connecting end 19 has a complementary tapered post. It is also conceivable that both the end portion 25 and the connecting end 19 have end faces in a plane perpendicular to the axis of rotation, which may be pressed together, for example, to form a frictional connection, or may also have teeth for torque transmission or torque synchronization for form-locking.

[0038] Because the detachable connector 26 allows for easy removal of the scraper 4 from the drive unit 22, a device 27 is also provided for the detachable connection between the scraper mechanism 4 and the drive unit 2. These will be referred to... Figure 1 and Figure 3 A more detailed explanation follows below. Figure 3 A magnified detail view of device 27 is shown.

[0039] The device 27 now has a plurality of resiliently movable locking elements 28. According to this embodiment, these are arranged on the drive unit 22 and are supported laterally or parallel to the plane of the printing screen 3. The locking elements 28 are configured in the form of locking wedges, which are each spring-forced toward the output shaft 24 by preloaded springs 29. At least two locking elements 28 are now supported opposite each other on the scraper mechanism holder 30 of the drive unit 22, to which the scraper mechanism 4 is detachably fixed by the device 27.

[0040] The scraper mechanism 4 has a plurality of mating locking elements 31 corresponding to the number of locking elements 28. The mating locking elements 31 are, for example, fixed in the frame and / or housing 18 and extend substantially parallel to the drive shaft 17 from the housing 18. Each mating locking element 31 here has a lateral notch 32, wherein the notches 32 of opposing locking elements face away from each other and thus face the corresponding locking element 28. The notches 32 are configured such that they can accommodate a portion of the corresponding locking element 28, particularly as... Figure 3 As shown. The reverse locking element 31 has an insertion angle 33 or a starting angle on its end facing away from the housing 9. When the scraper mechanism 4 is fed to the drive device 22, the corresponding locking element 28 is pressed back against the force of the preload spring 29 by the insertion angle or starting angle. To facilitate repositioning, the locking element 28 also has a starting angle 34 or an insertion angle, which interacts with the insertion angle 33 of the corresponding locking element 31.

[0041] like Figure 2 As shown, every two locking elements 28 are now connected to each other by a crossbar 28', thus forming a U-shaped locking element.

[0042] Once the reverse locking element 33 or scraper mechanism 4 is guided far enough toward the drive unit 22 such that the end 25 and the connecting end 19 are effectively interconnected and the corresponding locking element 28 is fully at the height of the notch 32, the spring force of the preload spring 29 pushes the corresponding locking element 28 into the corresponding notch. Thus, the scraper mechanism 4 is form-locked onto the drive unit 22 and effectively connected to the motor 23 via the connector 26. To disengage the scraper mechanism 4 from the drive unit 22, the locking element 28 is pushed back against the force of the corresponding preload spring 29, and thus removed from the corresponding notch 33, after which the scraper mechanism 4 can be easily pulled down from the drive unit 22. Here, the effective connection between the connecting end 19 and the output shaft 24 is also disengaged without any other measures, especially without tools. Because the transmission device 35, consisting of worm gears 14 and 15 and worm shaft 16, is self-locking, the scraper blades 5 and 6 remain in their last set pivot position after the scraper mechanism 4 is removed from the drive unit 22. The user can then manually change the pivot position of the scraper mechanism 4 by manually applying torque to the connecting end 19.

[0043] Advantageously, before disengaging from the drive unit 22 and scraper mechanism 4, the scraper blades 5 and 6 are moved to a transport position in which they are arranged in a V-shape with relative inclinations to each other, such that their free scraper edges 7 and 8 abut against each other, as shown in the image. Figure 1 As shown. Figure 1 Solid lines show scraper blades in the V-shaped transport position, while dashed lines show scraper blades in other exemplary scraper positions.

[0044] The self-locking mechanism 35 ensures that the squeegee blades 5 and 6 remain in the transport position, thus accommodating and preserving the printing material, which may be located between the squeegee blades 5 and 6, within the space between them. When transporting the squeegee mechanism 4, the printing material cannot leave the space formed between the squeegee blades 5 and 6 and the transverse paste restrictor 13. This ensures the safe transport of the printing material or printing paste, allowing the squeegee mechanism 4 to be moved, for example, from one printing table to another or from one printing table to a cleaning device without loss of printing material. In this cleaning device, any remaining printing material can be selectively removed and prepared for reuse. This reduces the overall consumption of printing material. Since the squeegee mechanism 4 is detachably fixed to the drive unit 22, this also automatically creates an effective connection between the transmission mechanism 35 and the drive unit 22, allowing for safe and quick manual and automatic attachment and detachment of the squeegee mechanism 4 from the transmission unit 22.

[0045] Figure 4AThe scraper device 1 is shown in a simplified perspective view. Also shown in the figure is a lifting device 36 for the printing apparatus 2, which allows the entire drive unit to be lowered and raised, as indicated by double arrows 37.

[0046] Figure 4B The side view shows the lifting device 36 in the scraper device 1. Figure 4C A simplified top view of the lifting device 36 is shown.

[0047] According to this embodiment, the lifting device 36 is configured as a spindle lifting device with two lifting spindles 38, each guided through the threads of the support 45 of the drive device 22, such that the drive device translates or moves axially along the lifting spindle 38 as the respective lifting spindle 38 rotates. To drive the lifting spindles 38, a belt drive 39 is used, having a drive motor 40, particularly an electric motor, effectively connected to the drive wheel 41, and a belt 43 guided around a plurality of guide rollers 42 and rollers 44 fixed at one end to / around the lifting spindle 38. Preferably, at least one of the guide rollers is arranged radially elastically as a tensioning roller, so that the torque of the drive motor 40 can be transmitted to the lifting spindle 38 via the belt 43. Therefore, via the lifting device 36, the drive device 22, together with the scraper mechanism 4 arranged therein, can descend onto or detach from the printing screen or printing template.

[0048] The scraper mechanism retainer 30 is pivotally held on the bracket 45 of the drive unit 22. For this purpose, the scraper retainer 30 has bearing bolts 46 on each of its two opposite ends, which are rotatably supported in the bearing receiving portion 47 of the bracket 45. Thus, the entire scraper mechanism retainer 30 is pivotally supported about an axis, which in particular... Figure 4A The central axis 48 is shown and extends particularly parallel to the rotation axes of axes 10 and 11. Here, the central axis 48 intersects specifically with the central longitudinal axis of the worm shaft 16. As the squeegee mechanism retainer 30 pivots, the squeegee mechanism 4, connected to it via the locking device 27, also pivots, and the squeegee blades 5 and 6 pivot along with the squeegee mechanism. This ensures optimal squeegee angle setting during the printing operation.

[0049] like Figure 1 and 4AAs exemplarily shown, at least one pneumatic actuator 49 is present to pivot the scraper mechanism retainer 30. The scraper mechanism retainer 30 has two back-to-back protrusions 50, each arranged on a longitudinal side extending parallel to the central axis 48 of the scraper mechanism retainer and projecting laterally to form an L-shape. According to this embodiment, each of these protrusions is assigned a pneumatic actuator 49. Each pneumatic actuator has a pneumatic piston 51 that interacts with the protrusion 50 and is movably supported in a cylinder, specifically tangentially to the central axis 48. By controlling the actuators, the scraper mechanism retainer 30, and thus the scraper mechanism 4, can be pivoted specifically about the central axis 48.

[0050] The pneumatic force applied to the scraper mechanism retainer 30 ensures elasticity through the pneumatic medium, enabling the scraper mechanism retainer 30 to pivot against the actuation direction. Therefore, for example, when one of the scraper blades 5 or 6 encounters an insurmountable object, the scraper mechanism 4 can pivot against the force of the actuator 49. This protects the scraper blades 5 and 6 and ensures a long service life for the scraper mechanism 4.

Claims

1. A squeegee mechanism (4) for a printing apparatus (2) for printing a planar substrate, the squeegee mechanism (4) having two squeegee blades (5, 6) extending parallel to each other and pivotally supported, characterized in that, The two scraper blades (5, 6) are effectively connected to the transmission device (35), and the two scraper blades (5, 6) are effectively connected to each other through the transmission device (35). The transmission device (35) is self-lockingly constructed as a worm gear transmission device and can be connected to the drive device (22). The transmission device (35) has a drive shaft (17) connected to a worm shaft (16), and the drive shaft (17) has a connecting end (19) configured to detachably connect the drive shaft (17) to the drive device (22).

2. The scraper mechanism according to claim 1, characterized in that, The scraper blades (5, 6) can be pivoted to a V-shaped transport position via the transmission device (35), in which the scraper blades (5, 6) can abut against each other at their free scraper working edges (7, 8).

3. The scraper mechanism according to claim 1 or 2, characterized in that, Each scraper blade (5, 6) is arranged on a rotatably supported shaft (10, 11) for pivoting, wherein a worm wheel (14, 15) is torsionally arranged on each shaft (10, 11), the worm wheel (14, 15) engaging with a worm shaft (16), the worm shaft (16) being connectable to the drive unit (22).

4. The scraper mechanism according to claim 1 or 2, characterized in that, The connecting end (19) is configured as a component of a shape-locking or friction-locking connector (26).

5. The scraper mechanism according to claim 1 or 2, characterized in that, The scraper mechanism has a housing (18), the transmission device (35), the scraper bracket (9) and the scraper blades (5, 6) are held in or on the housing, wherein the drive shaft (17) is guided outward through an opening in the housing (18).

6. The scraper mechanism according to claim 1 or 2, characterized in that, The scraper mechanism (4) has a means (27) for detachably fixing to the drive device (22).

7. The scraper mechanism according to claim 6, characterized in that, The device (27) is configured as a locking device.

8. A scraper device (1) for a printing apparatus (2) for printing a planar substrate, the scraper device (1) having a scraper mechanism (4) and a drive device (22) for the scraper mechanism (4), characterized in that, The scraper mechanism (4) is configured as a scraper mechanism according to any one of claims 1 to 7.

9. The scraper device according to claim 8, characterized in that, The drive unit (22) has an electric motor (23) that can be connected to the transmission unit (35).

10. The scraper device according to claim 8 or 9, characterized in that, The drive device (22) has an output shaft (24) with an end (25) connected to the transmission device (35).

11. The scraper device according to claim 10, characterized in that, The end (25) of the output shaft (24) is configured for a detachable connection with the drive shaft (17) of the transmission device (35).

12. The scraper device according to claim 8 or 9, characterized in that, The drive unit (22) has a scraper mechanism retainer (30) which can be detachably connected to the scraper mechanism (4).

13. The scraper device according to claim 8 or 9, characterized in that, The scraper mechanism (4) has a device (27) for detachably fixing to the drive device (22), the device (27) having at least one elastically deformable or displaceable locking element (28).

14. The scraper device according to claim 12, characterized in that, The scraper mechanism retainer (30) is pivotally supported about a central axis (48) extending parallel to the shafts (10, 11).

15. The scraper device according to claim 14, characterized in that, The scraper mechanism retainer (30) has a controllable actuator at at least one protrusion (50) remote from the central axis (48) for pivoting the scraper mechanism retainer (30).

16. The scraper device according to claim 15, characterized in that, The controllable actuator is configured as a pneumatic actuator (49) having a lifting piston assigned to the protrusion (50), the lifting piston being tangentially displaced with respect to the central axis (48).

17. A printing apparatus for printing planar substrates, comprising a squeegee device (1), characterized in that, The scraper device (1) is constructed as described in any one of claims 8 to 16.

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