EP0423428A2 - Method and apparatus for adjusting the position of a printing squeegee and a flood squeegee in screen printing - Google Patents

Abstract

In a method for adjusting the position of a printing squeegee and a flood squeegee in screen printing, the position-adjusting force, with which the printing squeegee is pressed against the fixed base of the printing carrier, and the position-adjusting force, with which the flood squeegee is pressed against the printing medium applied to the screen stencil during the flooding operation, are generated in each case by a pneumatic or hydraulic control circuit which is independent of the control circuit of the flood squeegee or the printing squeegee, the respective position-adjusting force being optimised by setting the pressure of the pressure medium initially in one or more trial prints or from empirical values and then being kept constant at this determined value in the following prints. A device for carrying out this method employs at least one cylinder unit for generating the respective position-adjusting force and a pressure controller for keeping the pressure of the pressure medium constant, the control circuit of the cylinder unit for the flood squeegee being independent of the control circuit of the cylinder unit for the printing squeegee. To compensate for the weight, the flood squeegee is prestressed in the direction facing away from the screen stencil.

Description

The invention relates to a method for delivering a pressure doctor blade of defined and constant elasticity and a flood doctor blade during screen printing.

The invention further relates to a device for performing this method.

In addition to a squeegee, the screen printing machines considered here have a flood squeegee, which is alternately lowered with the squeegee and has the task of transporting the printing medium applied to the stencil after the advancement through the squeegee during a printing process and thereby distributing it over the stencil.

As is well known, the quality of screen printing depends on many factors, some of which have not yet been mastered with conventional screen printing machines. This includes not only a precisely defined contact pressure of the squeegee for sealing between the screen stencil and a solid base during the printing process, but also an exactly defined contact pressure of the squeegee against the pressure medium applied to the screen stencil during the flooding process. The Infeed force with which the flood knife is pressed against the printing medium applied to the screen stencil during the flooding process, and the distance between the bottom edge of the flood knife and the screen stencil, have a decisive influence on the type of application of the printing medium on the screen stencil and thus the result of the subsequent printing process.

Up to now, little importance has been attached to delivering the flood knife. It was overlooked that the uniform placement of the printing medium on the screen stencil decisively influences the quality of the screen printing. Irregularities in flooding are reflected in the pressure.

The setting and maintenance of the contact pressure of the pressure or flood doctor blade become particularly difficult in that the doctor blades have to be lifted off the screen stencil before they are returned and lowered again after their return with the same pressure on the screen stencil. The feed force must remain constant over a large number of printing processes. However, this goal can only be achieved if a pressure squeegee of defined and constant elasticity is assumed. Older squeegees, which do not have these properties, do not allow stable and controllable conditions and thus no clean and even screen printing.

A method of the type mentioned is described in the older German patent application P 38 42 419.3. The infeed force with which the squeegee is pressed against the solid base, for example a flat table or a drum, is first optimized in one or more test prints and then kept constant at this value in the subsequent prints. A pneumatic or hydraulic cylinder unit can be used to generate the feed force serve, the delivery force is initially optimized by adjusting the pressure of the printing medium in the test prints and the pressure is then kept constant in this value determined in the subsequent prints.

A method for delivering the flood doctor blade, in which the feed force with which the flood doctor blade is pressed against the printing medium applied to the screen stencil during the flooding process, is precisely defined and kept constant is not described in the earlier German patent mentioned. The flood knife is also assigned a cylinder unit. However, this serves to move the flood doctor blade up and down during screen printing. This older patent application does not show that it can also be used to adjust the delivery force. Only the feed path of the flood knife to the screen template is limited by a stop, which e.g. can be located on a locking ring which is arranged on a piston rod extending upward from the cylinder unit for the flood doctor blade. Since the cylinder unit assigned to the flood doctor serves only for the alternating movement of the flood doctor, it is obvious that the control circuit for the cylinder unit is connected to the control circuit for the cylinder unit of the printing doctor. With such a method, however, an optimally defined delivery of the flood doctor blade is not guaranteed.

Other known methods for delivering a pressure doctor and a flood doctor use mechanical adjustment devices, such as e.g. Spindles to define the infeed force beforehand. However, these measures are by no means optimal for screen printing that is clean and even, even with large print runs.

The invention has for its object a method to deliver a printing squeegee and a flood squeegee, which ensures a precisely defined delivery of the printing squeegee and flood squeegee, which delivers an optimal screen print that can also be reproduced over a large print run.

The object is achieved in that the feed force with which the squeegee is pressed against the fixed base of the printing medium, and the feed force with which the squeegee is pressed during the flooding process against the compression medium applied to the stencil, by one each from the control circuit of the Flood doctor or the pressure doctor independent pneumatic or hydraulic control circuit is generated, the respective feed force is initially optimized by adjusting the pressure of the printing medium in one or more test prints or from experience and then kept constant in the subsequent prints at this determined value.

Due to the independent control circuits for the pressure and flood squeegees, the feed force of the pressure squeegee and the flood squeegee can be optimally adjusted in test runs. In the subsequent prints, the doctor blades are then lowered with the same respective delivery force that was used in the last test prints. The delivery movement of the printing squeegee is finally limited by the fixed base of the printing medium after the printing squeegee has lowered onto the screen stencil with the determined constant delivery force and pressed it onto the printing medium. The infeed movement of the flood doctor blade is limited by the pressing means applied to the screen template after the flood doctor blade has lowered onto it with the determined constant infeed force. By keeping the respective delivery force constant, it is then guaranteed that also the same print quality is achieved with repeated repetitions.

In such designs of screen printing machines, in which the screen template is held in a pivotable frame, care must be taken to ensure that the squeegee is only lowered when the screen template is first pivoted back onto the print carrier and thus onto the solid base. Such a sequence of movements can be achieved by incorporating a time delay. In order to prevent the screen stencil from being destroyed by the printing squeegee in the event of a failure of such a delay circuit, the delivery path of the printing squeegee measured in the last test prints to the solid base is preferably used in the aforementioned method, as already described in P 38 42 419.3 subsequent prints kept constant. Fixing the feed path of the flood knife to the screen template is also expedient and may be necessary during flooding and in particular at higher speeds, the flood knife can penetrate deeper into the printing medium with a constant feed force, which leads to an uneven placement of the printing medium on the screen template. Therefore, the feed path of the flood doctor to the screen stencil measured during optimization of the feed force is preferably fixed before flooding and kept constant during flooding.

In a device according to the invention for carrying out the method described above, it is proposed that at least one cylinder unit, consisting of a cylinder and a double-acting piston with a piston rod, be provided for generating the respective feed force, and a pressure regulator is provided for keeping the pressure of the pressure medium constant, the Control circuit of the cylinder unit for the flood doctor blade is independent of the control circuit of the cylinder unit for the pressure doctor blade.

Keeping the pressure constant has proven to be particularly favorable in practice, although basically other options for keeping the feed force defined by adjusting the pressure constant are being considered.

Since the flood knife during the flooding process may only bear a relatively low pressure on the compression medium applied to the screen template, the flood knife is preferably biased in the direction facing away from the screen template.

It is expedient that the feed force of the flood doctor blade is generated exclusively by the cylinder pressure. Therefore, the amount of prestress is preferably at least equal to the weight of the flood doctor blade and its doctor blade holder. The bias can e.g. be generated by a tension spring or a counter cylinder.

The described prestressing of the flood doctor blade in the direction facing away from the screen template also has the advantage that the change between the downward and upward movement of the flood doctor blade can be carried out very quickly.

The cylinder unit used to feed the respective doctor blade is preferably carried by a guide block which has a guide for a holding device of the doctor blade holder connected to the piston rod of the cylinder unit.

In a preferred embodiment, the holding device has a cylindrical part which is displaceably guided in a bearing sleeve arranged in the guide block and has a central bore in which a ball is arranged without play and through which the piston rod runs with lateral play, the lower end of the piston rod being firmly connected to the ball.

With the help of this construction, a rigid parallel guidance of the piston rod, which could possibly cause the piston rod to jam in the guide block, is avoided.

To arrange the ball without play, the bore of the cylindrical part expediently has a cylindrical extension at one end with an internal thread and a hemispherical base region, the radius of which corresponds to the radius of the ball. A counterpart with a dome-shaped recess directed towards the ball is then screwed into the cylindrical extension, to which the doctor holder is attached.

Since tilting can occur in the vertical plane with longer doctor blades, the holding device is preferably fixedly connected at the end opposite the piston rod to a compensating element which can be rotated on or in the doctor blade holder with limited play about an axis pointing in the horizontal guide direction of the pressure or flood doctor blade and is arranged displaceable in the horizontal transverse direction to the axis.

The compensating element is expediently arranged between two side walls of the doctor blade holder which extend in the horizontal transverse direction of the pressure or flood doctor blade and has an elongated hole which extends in the same direction and in which a block is arranged so as to be displaceable in the direction of expansion of the elongated hole, with the aid of the block a bolt which extends perpendicularly to the two side walls and is fastened rotatably to the two side walls.

A particularly stable guidance can be achieved in that the pressure doctor blade and the flood doctor blade or their doctor blade holder are carried by one and the same guide block which has parallel guides for the holding devices of the two doctor blade holders.

The common guide block for the two doctor blades also has the advantage that they can be easily pivoted with the guide block. The doctor blades can be easily exchanged or cleaned by swiveling the guide block.

For this purpose, the guide block can be pivotally supported by a shaft which extends in the horizontal transverse direction of the pressure and flood doctor blade and which is rotatably mounted in a guide block for the pivoting movement.

A pneumatic or hydraulic cylinder unit, which consists of a cylinder and a double-acting piston with a piston rod and is carried by the guide block for the pivoting movement, is preferably used to generate the pivoting movement. A gear wheel which is fixedly connected to the shaft can be mounted in the guide block and can be actuated and locked by a gear rack connected to the piston rod of the cylinder unit.

In order to enable the doctor blade to be easily replaced or cleaned, the guide block can preferably be pivoted by approximately 900 relative to the vertical position.

• Fig. 1 einen Schnitt in der Vertikalebene der Flutrakel durch die Siebschablone sowie darüber eine schematisch vereinfachte Ansicht der Flutrakel mit den darüber angeordneten Zustellvorrichtungen,
• Fig. 2 einen quer zu dem Schnitt der Figur 1 geführten Schnitt durch die Siebschablone, die darüber angeordnete Druck- und Flutrakel und die darüber befindlichen Zustellvor­richtungen mit teilweise aufgebrochener Ansicht,
• Fig. 3 eine Teilansicht des Schnittes längs der Linie III-III in Fig. 2, aus der insbesondere die Verbindung zwischen Kolbenstange und Rakelhalter und das zwischengeschaltete Ausgleichselement ersichtlich sind, und
• Fig. 4 eine teilweise aufgebrochene Ansicht der Lagerung der die Zustellvorrichtungen tragenden Welle sowie der Schwenkvorrichtung für die Welle.

An embodiment of the invention is described below with reference to the drawing. The drawing shows:

• 1 shows a section in the vertical plane of the flood doctor blade through the screen template and, above it, a schematically simplified view of the flood doctor blade with the delivery devices arranged above it,
• 2 shows a cross section of the FIG. 1 section through the screen stencil, the printing and flood squeegee arranged above it and the delivery devices above it, with a partially broken view,
• Fig. 3 is a partial view of the section along the line III-III in Fig. 2, from which in particular the connection between the piston rod and doctor holder and the intermediate compensating element can be seen, and
• Fig. 4 is a partially broken view of the storage of the shaft carrying the feed devices and the pivoting device for the shaft.

The device shown in the figures works according to a method to be described below. The device shown in FIG. 1 corresponds to the device shown in FIG. 2 except for the locking device contained in FIG. 2 and discussed below. 1 shows a section along the line I-I in FIG. 2.

The device shown in FIG. 4 connects to the shaft shown in FIG. 1 on the left. A corresponding symmetrical device is connected to the shaft on the right.

In the screen printing unit shown in FIGS. 1 and 2, the flood knife 1 is lowered into the flood position. The screen template 2 is lifted during the flooding process from the print carrier (not shown in the drawing) and the solid base. The printing medium 3 is applied to the screen stencil 2, which is transported back from the flood knife 1 in the direction of arrow 4 after the printing process and is thereby distributed over the screen stencil 2. The pressure doctor blade 5, which is arranged approximately parallel to the flood doctor blade 1, is raised during the flooding process, so that it cannot impair the flooding of the printing medium 3.

After the flooding process, the screen template 2 is moved downward again to a small distance from the print carrier arranged on the fixed base. The up and down movement of the screen template 2 is effected in the screen printing machine on which this is based, by a pivotable frame in which the screen template 2 is clamped. Then the squeegee 5 is lowered against the screen template 2, which is pressed against the solid base for sealing between the screen template 2 and the fixed base.

It is assumed that a squeegee 5, which comprises a doctor blade 6 made of thin sheet steel and at the lower end of which a doctor blade profile 7 made of a flexible plastic.

The flood squeegee 1 and the pressure squeegee 5 are each clamped in a squeegee holder 8, which is supported by a guide block 9 via a holding device to be described, which is in turn pivotally supported by a shaft 10. As shown in FIG. 4, the shaft 10 is rotatably mounted in a guide block 12, which is arranged towards a side wall 11 of the screen printing machine, for the pivoting movement.

Above the guide block 9 for the upward and downward movement of the flood doctor blade 1 and the pressure doctor blade 5 are two cylinder units 13 and 14, each of which consists of a cylinder 15 or 16 and a double-acting piston 17 which is supported by a continuous piston rod 19 or 20 is worn. The piston rod 19 or 20 protrudes from the top of the cylinder unit 13 or 14. The lower end of the piston rod 19 or 20 is connected to the holding device for the respective doctor blade holder 8 to be described.

The cylinders 15 and 16 are supplied with compressed air via compressed air connections 21 and 22 by control circuits which are independent of one another, corresponding to the respective changing position of flood knife 1 and pressure knife 5, above or below the piston 17.

Since a single guide block 9 is not sufficient in the case of a longer flood knife 1 and pressure knife 5, two guide blocks 5 which are identical to one another are shown in FIG. 1.

The delivery devices for the flood doctor blade 1 and the pressure doctor blade 5 carried by the two guide blocks 9 are also identical.

As can be seen from FIG. 2, the flood knife 1 is prestressed in the direction facing away from the screen template 2. The pretension is generated by a tension spring 25 which is arranged between an arm 26 fastened to the doctor holder 8 and an arm 27 fastened to the guide block 9. The bias voltage compensates for the weight of the flood doctor blade 1, the doctor blade holder 8 and the holding device of the doctor blade holder 8 guided through the guide block 9.

The holding device for the flood doctor blade 1 or the pressure doctor blade 5, which has already been mentioned several times, consists of a cylindrical part 28 or 29, which is guided displaceably in a bearing sleeve 30 or 31 arranged in the guide block 9 and has a central bore 32 or 33. The bore 32 or 33 has at its downward-facing end a cylindrical extension 34 or 35 with an internal thread and a hemispherical bottom region 36 or 37. In the cylindrical extension 34 or 35 a ball 38 or 39 is inserted, the Radius corresponds to the radius of the hemispherical base region 36 or 37.

The piston rod 19 or 20 of the cylinder unit 13 or 14 arranged on the guide block 9 runs through the bore 32 or 33 from above. The outer diameter of the piston rod 19 or 20 is smaller than the inner diameter of the bore 32 or 33, so that the piston rod 19 or 20 has a lateral play. The lower end of the piston rod 19 or 20 is screwed from above into the ball 38 or 39 along the center thereof.

A counterpart 40 or 41 with a dome-shaped recess 42 or 43 directed towards the ball 38 or 39 is screwed into the cylindrical extension 34 or 35 from below, so that the ball 38 or 39 is free of play but rotatable in the extension 34 or 35 is arranged.

The counterpart 40 or 41 projects with its external thread downward relative to the cylindrical part 28 or 29 and is secured against being unscrewed from the cylindrical part 28 or 29 by a lock nut 44 or 45.

Is on the lower end of the counterpart 40 or 41 the squeegee holder 8 for the flood squeegee 1 or the squeegee 5 attached.

This attachment is made via a compensating element 46. 3, the compensating element 46 consists of an upper plate 47 and a lower block 48, which are screwed together. The plate 47 is fastened to the lower end face of the cylindrical part 28 and 29 by means of a screw 49 countersunk therein.

The lower block 48 has an elongated hole 50 which expands in the horizontal transverse direction of the flood doctor blade 1 or the pressure doctor blade 5. In the elongated hole 50, a cuboid block 51 is also arranged to be displaceable in the direction of expansion of the elongated hole 50. The cuboid block 51 has a bore 52 extending through the elongated hole 50.

This compensating element 46 is arranged between two side walls of the doctor blade holder 8, which extend in the horizontal transverse direction of the flood doctor blade 1 or pressure doctor blade 5. With the aid of a bolt extending through the bore 52 of the cuboid block 51, the block 51 is rotatably attached to the two side walls. The compensating element 46 can therefore rotate in the doctor blade holder 8 with limited play about an axis pointing in the horizontal guide direction of the flood doctor blade 1 or pressure doctor blade 5 and move it in the horizontal transverse direction to the axis.

As is apparent from Fig. 4, the shaft 10 carrying the guide block for the flood doctor 1 and the pressure doctor 5 extends through a bore 53 of the guide block 12 for the pivoting movement and is supported therein by a bearing sleeve (not shown in the drawing). In the guide block 12 a gear 54 is fixedly connected to the shaft 10, that is driven by a pneumatic cylinder unit 55 carried by the guide block 12, consisting of a cylinder 56 and a double-acting piston with a piston rod, for rotating the shaft 10. The piston rod of the cylinder unit 55 actuates a rack 57, which cooperates with the gear 54.

On the side of the guide block 12 remote from the shaft 10, a recirculating ball unit 58 is fixedly attached. In a screen printing machine that uses a table as a fixed support, the ball circulation unit 58 slides on a guide rail 59 arranged on a side wall 11 of the screen printing machine parallel to the table surface. If, on the other hand, a drum is used as a fixed support, the ball circulation unit 58 is fixed to the side wall 11 of the Screen printing machine arranged.

The cylinder unit 55 for the pivoting movement works in such a way that when compressed air is applied to the upper chamber of the cylinder 56, the guide block 9 is pivoted approximately into a horizontal position and fixed there. In this position, the flood doctor blade 1 and the pressure doctor blade 5 can be easily replaced or cleaned. By pressurizing the lower chamber of the cylinder 56, the guide block 9 is pivoted back into its vertical position and fixed there.

The guide block 9 is preferably attached to the shaft 10 by an expansion dowel 60. Such an expansion anchor 60 allows simple and quick adjustment of the angle setting of the guide block 9 with respect to the shaft 10, which is important for a precisely defined feed movement of the flood doctor blade 1 and the pressure doctor blade 5.

Fig. 2 shows, as already indicated, an additional locking device through which the the last test print measured delivery path of the printing squeegee 5 to the solid base and the flood squeegee 1 to the screen stencil 2 can be set and kept constant in the subsequent prints. This device is a locking ring 61 or 62, which is loosely displaceably placed on the continuous piston rod 19 or 20 and can be fixed on this by means of a locking screw 63 or 64. Instead of a locking screw, another mechanically, pneumatically or hydraulically adjustable stop can also be used. In addition, means, such as a certain pressure acting on the lower chamber of the cylinder 15, can be provided which prevent the flood knife 1 from lifting under the piston rod 19 under certain circumstances.

The delivery of the pressure doctor blade 5 and the flood doctor blade takes place in the case of a device equipped in this way as follows:

To adjust the flood doctor blade 1, it is lowered by applying air pressure to the cylinder 15 above the piston 17, toward the screen template 2, the locking screw 63 on the locking ring 61 being loosened. On the regulator for the air pressure in the cylinder 15, above the piston 17, a pressure value corresponding to the previous experience is set, which has the consequence that the flood doctor 1 presses with a defined feed force onto the pressing means 3 applied to the screen template 2.

A test flooding is then carried out with this air pressure and then checked whether it meets the desired quality requirements. If it is not yet satisfied, the air pressure is adjusted and another test flooding is carried out. This is repeated until a perfect order from the Compression means results. Then, with the flood knife 1 lowered, the locking screw 63 is tightened and the locking ring 61, which rests on the upper end face of the cylinder unit 13 due to its own weight, is blocked in this position. The locking ring 61 is now firmly connected to the continuous piston rod 19.

The delivery force for the pressure doctor blade 5 is optimized in a manner analogous to the above-described method for the flood doctor blade 1 by adjusting the air pressure in the cylinder 16. The air pressure in the cylinders 15 and 16 can also be optimized alternately during test flooding and subsequent test printing. The air pressures are adjusted until there is a perfect screen print. In particular, with the device described above, the air pressure values can then be kept constant even with a large number of subsequent pressure and flood processes.

Reference symbol list

• 1st flood knife
• 2. Screen template
• 3. Printing medium
• 4th arrow
• 5. Squeegee
• 6. Doctor blade
• 7. Doctor blade profile
• 8. Doctor blade holder
• 9. Guide block
• 10th wave
• 11. Sidewall
• 12. Guide block
• 13. Cylinder unit
• 14. Cylinder unit
• 15. Cylinder
• 16. Cylinder
• 17. Piston
• 19. Piston rod
• 20. Piston rod
• 21. Compressed air connection
• 22. Compressed air connection
• 25. Tension spring
• 26.arm
• 27.arm
• 28. cylindrical part
• 29. cylindrical part
• 30. Bearing sleeve
• 31. Bearing sleeve
• 32nd hole
• 33rd hole
• 34. cylindrical extension
• 35. cylindrical extension
• 36. hemispherical bottom area
• 37. hemispherical bottom area
• 38th bullet
• 39th bullet
• 40. counterpart
• 41. counterpart
• 42. dome-shaped recess
• 43. dome-shaped recess
• 44. lock nut
• 45. lock nut
• 46. Compensation element
• 47. top plate
• 48. lower block
• 49th screw
• 50th slot
• 51. Block
• 52nd hole
• 53rd hole
• 54th gear
• 55. Cylinder unit
• 56th cylinder
• 57. Rack
• 58. Ballscrew unit
• 59. Guide rail
• 60. Expansion dowels
• 61. Locking ring
• 62. Locking ring
• 63. Locking screw
• 64. Locking screw

Claims (14)

1. A method for delivering a pressure doctor blade of defined and time-constant elasticity and a flood doctor blade in screen printing, characterized in that the feed force with which the pressure doctor blade (5) is pressed against the solid base of the printing medium, and the feed force with which the flood doctor blade ( 1) is pressed during the flooding process against the pressure medium (3) applied to the screen stencil (2) by a pneumatic or hydraulic control circuit which is independent of the control circuit of the flood doctor blade (1) or the pressure doctor blade (5), the respective feed force being generated by Adjustment of the pressure of the printing medium is first optimized in one or more test prints or based on empirical values and then kept constant at this value in the subsequent prints. 2. The method according to claim 1, characterized in that the infeed paths measured in the test prints of the printing doctor (5) to the solid base and the flood doctor (1) to the screen stencil (2) are kept constant during the subsequent prints or during flooding. 3. Device for practicing the method after Claim 1 or 2, characterized in that for generating the respective feed force at least one cylinder unit (13, 14) consisting of a cylinder (15, 16) and a double-acting piston (17) with a piston rod (19, 20), and A pressure regulator is provided to keep the pressure of the pressure medium constant, the control circuit of the cylinder unit (13) for the flood doctor blade (1) being independent of the control circuit of the cylinder unit (14) for the pressure doctor blade (5). 4. The device according to claim 3, characterized in that the flood knife (1) is biased in the direction facing away from the screen template (2). 5. The device according to claim 4, characterized in that the amount of bias is at least equal to the weight of the flood knife (1) and its doctor holder (8). 6. Device according to one of claims 3 to 5, characterized in that the cylinder unit (13, 14) is carried by a guide block (9) which is a guide for a with the piston rod (19, 20) of the cylinder unit (13, 14th ) connected holding device of the doctor holder (8). 7. The device according to claim 6, characterized in that the holding device has a cylindrical part (28, 29) which is displaceably guided in a bearing sleeve (30, 31) arranged in the guide block (9) and a central bore (32, 33) has in which a ball (38, 39) is arranged without play and through which the piston rod (19, 20) with a lateral play runs, the lower end of the piston rod (19, 20) being fixedly connected to the ball (38, 39). 8. The device according to claim 7, characterized in that the bore (32, 33) of the cylindrical part (28, 29) has at one end a cylindrical extension (34, 35) with an internal thread and a hemispherical bottom region (36, 37) , the radius of which corresponds to the radius of the ball (38, 39), and a counterpart (40, 41) with a spherical dome-shaped recess (42, 43), on which the doctor blade holder is screwed, is screwed into the cylindrical extension (34, 35) (8) is attached. 9. Device according to one of claims 6 to 8, characterized in that the holding device on the piston rod (19, 20) opposite end with a compensating element (46) is fixedly connected to or in the doctor holder (8) with limited play an axis pointing in the horizontal guide direction of the flood doctor blade (1) or pressure doctor blade (5) is rotatable and is displaceable in the horizontal transverse direction to the axis. 10. The device according to claim 9, characterized in that the compensating element (46) between two in the horizontal transverse direction of the flood doctor (1) or pressure doctor (5) extending side walls of the doctor holder (8) is arranged and an elongated hole extending in the same direction (50), in which a block (51) is arranged so as to be displaceable in the direction of expansion of the elongated hole (50), the block (51) being rotatable on the two side walls with the aid of a bolt extending perpendicularly to the side walls is attached. 11. Device according to one of claims 6 to 10, characterized in that the pressure doctor blade (5) and the flood doctor blade (1) or the doctor blade holder (8) of one and the same guide block (9) are carried, the parallel guides for the holding devices the two squeegee holders (8). 12. The apparatus according to claim 11, characterized in that the guide block (9) is pivotally supported by a in the horizontal transverse direction of the squeegee (5) and the flood squeegee (1) extending shaft (10) which is rotatable in a guide block (12) is stored. 13. The apparatus according to claim 12, characterized in that for generating the pivoting movement, a pneumatic or hydraulic cylinder unit (55) consisting of a cylinder (56) and a double-acting piston with a piston rod is provided, which of the guide block (12) is carried for the pivoting movement, and that in the guide block (12) a gear (54) is fixedly connected to the shaft (10), which can be actuated and locked by a gear rack (57) connected to the piston rod of the cylinder unit (55) . 14. The apparatus according to claim 11 or 12, characterized in that the guide block (12) is pivotable by approximately 90 ° with respect to the vertical position.

Images