EP2091734B1 - Printing machine for printing on a substrate - Google Patents

Abstract

The invention relates to a printing machine (3) for printing on a substrate (1), said machine (3) comprising the following features: - the central counter-pressure cylinder (2), - means for advancing the substrate (1) to the central counter-pressure cylinder (2), a pressure roller (4) for pressing the substrate (1) against the central counter-pressure cylinder (4), and - a plurality of impression cylinders (D1...D6) that can be applied to the central counter-pressure cylinder (4). The pressure roller (4) can be assembled from a mandrel (12) and at least one sleeve.

Description

The invention relates to a printing machine for printing a printing material web.

There are various types of printing machines are known, which can print on these substrates sheets or sheets.

Especially in the field of packaging printing web-shaped plastic films are often used as substrate, which are stretchable. However, the elasticity increases with the heat. A strong heat input takes place through the drying devices, which frequently apply hot air to the printing material. In order to avoid stretching and the associated register errors, such plastic films, but also other materials, are often printed on so-called central cylinder printing machines. The printing material web, which rests on the central impression cylinder, can be passed by mostly several inking units, which can print them with different colors and motifs.

However, before it reaches the first inking unit in its running direction, the printing material web must already rest completely on the central impression cylinder. After the printing material web has been brought from an unwinding device via one or more web guide rollers to the impression cylinder, it is usually pressed by means of a pressure roller to the impression cylinder, so that subsequently a displacement of the web can be excluded relative to the impression cylinder.

However, it was found in the past that printed material webs had some wrinkles or other damage after being pressed onto the impression cylinder. Such printing material webs or at least their folds having sections are no longer useful and therefore to dispose of as a committee. The tendency to show wrinkles is, according to observations, strongly dependent on the material of the printing material web. In particular, paper webs behave differently than plastic webs. Also, flat material differs in its properties of tubing in which two contiguous, superimposed layers of material are passed over the impression cylinder.

Investigations have shown that the surface properties of the pressure roller are responsible for such problems. Under surface properties are z. B. to understand the material properties of the surface layers or coatings, but also the geometric properties such as the diameter of the pressure roller. The geometric properties also include, in particular, grooves or grooves, which may be introduced into the surface of a pressure roller in various embodiments.

A conventional design is in EP-A-0 947 318 disclosed.

The object of the present invention is to propose a printing machine with which the risk of damage to the printing material webs is reduced.

According to the invention, this object is solved by the features of the characterizing part of claim 1. Accordingly, it is provided that the pressure roller of a mandrel and at least one sleeve is assembled. The mandrel of the pressure roller is a relatively small cylinder-like body in its diameter, which is supported and held with its first end in the printing press. The second end of the mandrel is mounted in a holder which is hinged in the frame of the printing machine, which holder is removable from the second end of the mandrel. The sleeve is a sleeve-shaped body which is relative to the mandrel is movable. When the retainer has been removed from the second end of the mandrel, the sleeve or sleeve can be easily pulled down axially from the mandrel. Subsequently, a sleeve can be pushed onto the mandrel.

To adapt the surface properties of the pressure roller so it is sufficient to adapt only the at least one sleeve in its surface properties of the material to be printed. For this purpose, a plurality of sleeves with different surface properties can be provided, from which a suitable for the material of the printing material sleeve can be selected in which the printing material carries as possible no damage. The surface properties may be determined by the nature of the surfaces (material, surface geometries), but also by the outer diameter of the sleeve.

These surfaces may differ, for example, in their hardness. So you need for printing hoses press rollers, which at least partially rubber covers of relatively high Shore hardness, so that the trapped between the film web air, which can lead to problems when printing, can be pushed out in the pressing on the impression cylinder. Only then are both superimposed webs of the hose also sufficiently well on the impression cylinder.

In order to avoid the problems described, sleeves are also used whose surfaces are at least partially provided with grooves.

In other, single-layer film webs or paper webs, however, these hard pressure rollers can cause damage, especially in thin films. Therefore, here sleeves with rubber coatings low Shore hardness can be used advantageously.

In these single-layer printing material webs and sleeves can be used, the surfaces of which are at least partially smooth, that is, no depressions, such as grooves include.

Preferably, the pressure rollers of the invention comprise sleeves which are at least partially covered with rubber flooring whose Shore hardnesses are between 60 and 80 Shore.

The invention also offers advantages when the properties of the sleeve have changed due to wear in the course of printing operation. In this case, a spare sleeve can be kept ready, which is then pushed onto the mandrel instead of the worn sleeve. Since now the removal, renewal or repair, such. As regrinding, and the incorporation of a conventional pressure roller is eliminated, the invention can lead to an enormous saving of time and thus to a significant reduction of expensive machine life.

Since the sleeve should rest on the mandrel in frictional engagement with the mandrel, but should be easy to move relative to the mandrel for replacement, it is necessary to lock the sleeve on the mandrel after sliding. For this purpose, a hydraulic tensioning device can be provided, which is integrated in the mandrel and which cause an increase in diameter of the mandrel in certain axial sections when they are pressurized. The corresponding with these sections sections of the inner sleeve of the sleeve in this first variant of an unyielding material.

In another variant of the sleeves, the inner sleeve may consist of resilient materials. The inner diameter of the inner sleeve is slightly smaller than the outer diameter of the mandrel, so that a sleeve frictionally rests on the mandrel. To change the sleeve, compressed air is injected between the outer surface of the mandrel and the inner sleeve of the sleeve, so that the inner diameter of the sleeve increases. Then the sleeve can be moved without much effort. But other locking options are conceivable that avoids a relative movement of the sleeve to the mandrel. These include, for example, magnetic or magnetizable elements, one of which in or on the sleeve and a may be arranged in or on the mandrel. Other possibilities include elements and materials that change their dimensions due to electrical variables such as voltage. These include, for example, piezo elements.

A mandrel can be designed so that both Sleevevarianten can be used on it. Of course, other variants are conceivable in which, for example, sleeve and mandrel are firmly connected or clamped together by mechanical means such as screws or wedges.

The present invention includes a selection of nip rollers for use on a printing press, the nip rollers of which comprise a mandrel and a sleeve. Advantageously, this system of printing press and multiple sleeves comprises different sleeves, which at least partially comprise rubber flooring of different Shore hardness. The sleeves may additionally include pads with different grooving or smooth surfaces. In this way, by applying suitable sleeves, the requirements already described above for printing single-layer or multi-layer printing material webs can be met in a simple manner.

For adjusting the pressure roller to the impression cylinder an actuator is preferably provided at each end of the pressure roller. These actuators act on the pressure roller with the necessary for employment of the impression cylinder contact pressure.

The actuators can act on linearly displaceable carriage, so that the Anstellweg is also rectilinear.

In a further preferred embodiment, the pressure roller is mounted in lever arms, so that the Anstellweg is located on a circular arc. The actuators then act on ends of these lever arms.

In a further embodiment of the invention, spring elements act on the ends of the pressure roller, which act on the pressure roller with a force which contains at least one component which is directed away from the impression cylinder. However, the spring force of the spring elements is smaller than the maximum contact force of the actuators. This measure serves to ensure that, if the maximum force of the actuators can not be applied, the pressure roller is automatically removed from the impression cylinder. The maximum force can be exceeded, for example, by damage to the actuator or, in the case of compressed-air-operated piston-cylinder units, by a decrease in the air pressure.

In a preferred embodiment of the invention piston-cylinder units are provided as actuators, in which the aforementioned spring elements are integrated. The spring elements are based on the bottom of the cylinder, which is formed for example by the housing bottom, and act on the piston.

Further embodiments of the invention will become apparent from the description and the claims.

Fig. 1

Seitenansicht einer Druckmaschine

Fig. 2

Ansicht der offenen Seite des Regals für Sleeves

Fig. 3

Draufsicht auf die Druckmaschine aus Fig. 1

Fig. 4a, b

Ausführungsbeispiele für Sleeves

Fig. 5

Seitenansicht einer weiteren erfindungsgemäßen Druckmaschine

Fig. 6

Wie Fig. 5, nur mit abgestellter Anpresswalze

Fig. 7

Draufsicht auf eine erfindungsgemäße Druckmaschine gemäß Fig. 5 und 6

Fig. 8

Ansicht VIII - VIII aus Fig. 7

Fig. 9

Wie Fig. 8, nur mit abgestellter Anpresswalze

Fig. 10

Schnitt durch einen als Kolbenzylindereinheit ausgestaltetem Aktuator

The individual figures show:

Fig. 1

Side view of a printing press

Fig. 2

View of the open side of the shelf for sleeves

Fig. 3

Top view of the printing press Fig. 1

Fig. 4a, b

Embodiments for sleeves

Fig. 5

Side view of another printing press according to the invention

Fig. 6

As Fig. 5 , only with the pressure roller off

Fig. 7

Top view of a printing press according to the invention Fig. 5 and 6

Fig. 8

View VIII - VIII from Fig. 7

Fig. 9

As Fig. 8 , only with the pressure roller off

Fig. 10

Section through an actuator designed as a piston-cylinder unit

FIG. 1 shows a functional diagram of a central cylinder flexographic printing machine 3 in the execution of a print job, to which all six inking units Fn are required. Therefore, all printing cylinders D1 to D6 are shown in their printing position.

In the illustrated function sketch of the normal mechanical components of such a machine, only the impression cylinder 2 and the pressure cylinder D1 to D6 were shown. The other components are well known to those skilled in the art and partly also in the document US 6,634,297 B2 shown. After the printing substrate 1 has been pressed by the pressure roller 4 to the central impression cylinder 2, it is 1 of the impression cylinder 2 past the pressure cylinders D1 to D6. Here, the web 1 passes through the printing zones DZ1 to DZ6 between the respective printing cylinders D1 to D6 and the impression cylinder 2 to be printed there. Finally, the web leaves 1 after the last printing unit F6 the impression cylinder 2 in its transport direction z.

The FIG. 2 shows various elements of a printing press 3 according to the invention in a perspective view. At both ends of the central impression cylinder, the plates 10, 11 are shown. These plates 10 and 11 are components of the machine frame, in which, inter alia, the impression cylinder 2 is rotatably mounted. Again, the substrate web 1 can be seen, which is guided around the impression cylinder 2 around. For the sake of clarity, the illustration of printing unit or inking cylinder has been omitted in this figure.

The pressure roller 4 comprises a mandrel 12, on which a sleeve 13 is applied, wherein the sleeve 13, after cancellation of a frictional connection, in the axial direction of the mandrel is displaceable.

The mandrel 12 is mounted at both ends in suitable bearings 14, for example in ball or needle bearings. The bearings are connected to carriages which are linearly displaceable on frame-fixed guide rails 15. The pressure roller 4 is thus with a rectilinear motion to the impression cylinder. 2 unemployable. Alternatively, the bearings 14 may also be mounted in pivot arms, which are pivotable about a frame-fixed pivot point, so that the pressure roller 4 can be pivoted to the impression cylinder 2, as it is based on the FIGS. 5 to 9 will be described in more detail.

However, the carriage can be released from the bearing 14 and moved, as shown in the figures with reference to the plate 10 associated carriage. For this purpose, the carriages may comprise shell pieces 17, a first of which is pivotally attached to a second so that the bearing 14 is clamped between both shell pieces 17 when the first is in the pivoted position. In this position, the shell pieces can be fixed to each other, which can be carried out for example by means of a screw connection. The screw connection can be made and released via a hand lever 19. After loosening the fixation and the moving away of the shell pieces 17, the path in the axial direction of the mandrel 12 is free in order to be able to remove the sleeve 13 unhindered.

In order to allow the exchange of the sleeve 13, at least one of the two plates 10, 11 has a window-like opening 18, through which the sleeve can be pulled off the mandrel. I'm in the FIG. 2 In the embodiment shown, the movement mechanism assigned to the plate 10 for adjusting the pressure roller 4, which comprises the slide and the guide rail, is assigned to the side of the plate 10 facing away from the impression cylinder 2. In this way, the hand lever 19, which serves for releasing or for producing the screw connection between the two bearing pieces 17, can be easily reached by the machine operator without having to grasp through the window-like opening 18. In this embodiment, the mandrel 2 passes through the aperture 18.

The hiring of the pressure roller 4 to the impression cylinder 2 are actuators 20, such as piston-cylinder units, which are attached to the machine frame and on the carriage, with which the pressure roller is moved act. Each end of the pressure roller can a Be assigned actuator 20. Such an actuator can preferably be driven hydraulically, pneumatically or by electric motor.

The contact force of the pressure roller is controllable, preferably adjustable. In this way, the adjusting force can be adapted in particular to the material of the printing material web.

At least one actuator can occupy at least three predefined positions. The first of these is the position in which the pressure roller is employed on the impression cylinder, the second of which is the position in which the pressure roller is turned off by impression cylinder, that is no longer in contact with it. When moving to the third position of the relevant carriage is moved relative to the mandrel, so that the sleeve is then freely accessible to be withdrawn axially.

The Fig. 3 shows again some in the FIG. 2 shown elements in the side view.

The FIGS. 4a and 4b show nip rollers 4, each comprising a mandrel 12 and a sleeve (sleeve) 13. The illustrated sleeves 13 are each covered on their outer surfaces with grooves 21, 22. The angles of the grooves which they occupy with the axis of rotation of the mandrel 12 are different in the figures. As an angle here is meant in each case the smallest angle, the axis of rotation and groove can take. The sleeves 13 in the FIGS. 4a and 4b So represent embodiments for sleeves 13 with different surface properties.

In the FIG. 4a the grooves make an angle of at least 45 degrees with respect to the axis of rotation.

In the FIG. 4b this angle is at most 45 degrees.

The FIG. 5 shows a further embodiment of a printing machine according to the invention. In this case, the bearing 14 is not complete in operation encompassed. Rather, a recess of the lever arm 30 surrounds the bearing 14. The lever arm 30 and the bearing 14 can also be connected to one another with a screw, for example a hand-operated knurled screw. This lever arm 30 is rotatably mounted on the pin 31, which is arranged fixed to the frame, so that it can be pivoted relative to the plate 10 and thus relative to the counter-pressure cylinder 2. The bearing 14 remote from the part of the lever arm 30 is pivotally connected to an actuator 32 at the pivot point 33. In addition, the actuator 32 is pivotally connected to the plate 10 at the pivot point 34. The actuator, which is preferably configured as a compressed-air-operated piston-cylinder unit, thus moves the lever arm 30 so that it is pivoted away from the bearing 14 of the pressure roller by its operation, in the case of the piston-cylinder unit by the displacement of the piston rod 35. If the lever arm 30 and the bearing be connected to each other, as described above, the pressure roller 4 is lifted from the surface of the impression cylinder 2 by the actuation of the actuator 32.

In the case of using a piston-cylinder unit as an actuator, it can be acted upon with compressed air in both directions of movement (see Compressed air connections in FIG Fig. 10 ). This means that the piston, which is located within the piston-cylinder unit, can be pressurized from both sides with compressed air. This has the consequence that can be pressed by means of this unit, the pressure roller to the impression cylinder or swing. The use of a pneumatically actuable piston-cylinder unit is advantageous at this point, since the compressibility of air leads to a certain elastic effect.

The FIG. 6 shows the same view as the FIG. 5 However, now the lever arm 30, which may also be referred to as a roll holder, as far as pivoted away from the bearing 14 that the sleeve 13 on the visible end of the pressure roller 4 of the Anpresswalzendorn 12 is removable. Furthermore, a spring 36 is provided which acts on the lever arm 30 with a force, so that when no force is exerted on the lever arm by the actuator, the pressure roller remains pivoted away from the impression cylinder. In the Using a piston-cylinder unit is preferred, a spring directly on the piston 37 (see Fig. 10 ) to act. For this purpose, a spring is preferably used in the cylinder 38 (see Fig. 10 ). The expert is clear that he - depending on the installation position of the spring - has to provide a compression or a tension spring. In the embodiment 10, a compression spring is provided. Such a piston-cylinder unit with integrated spring element has the great advantage of a compact design.

When using a piston-cylinder unit, by providing a spring which applies a permanent force to the lever arm, it can be avoided that during operation pauses in which the air pressure within the piston-cylinder unit decreases, the pressure roller due to the lack of air pressure and due to its gravity the impression cylinder falls. If the pressure roller is in contact with the impression cylinder for an extended period of time without the two turning, there is the risk that the sleeve of the pressure roller will get flat or dents, so that concentricity and thus the proper functioning of the pressure roller will be impaired.

1. 1.) Anpresswalze an den Gegendruckzylinder angestellt
2. 2.) Anpresswalze vom Gegendruckzylinder abgehoben
3. 3.) Hebelarm vom Lager abgeschwenkt (Wechselposition für die Hülse 13)

The lever arm 30 is in a position in which the pressure roller is lifted from the impression cylinder 2, and the lever arm 30 is connected to the bearing 14 of the pressure roller, there are now several conceivable ways to swing the lever arm 30 of the bearing to to replace the sleeve 13 can. Of course, first the connection between bearing 14 and lever arm 30 must be solved. Then the lever arm can be further pivoted by means of the actuator. If a piston-cylinder unit is provided as the actuator, then this must be at least three-stage. These three stages would have to be linked to the following positions of the lever arm:

1. 1.) Anpresswalze employed on the impression cylinder
2. 2) lifted off the pressure roller from the impression cylinder
3. 3.) Lever arm pivoted away from the bearing (change position for the sleeve 13)

However, it is also possible to release lever arm 30 and actuator 32 from each other in order to pivot the lever arm manually. The separation of this compound takes place approximately at the fulcrum 33.

While in the Figures 5 and 6 the so-called operating page, with which the side of the printing machine is meant, over which the sleeves 13 are pushed and pulled, is based on the FIGS. 7 . 8 and 9 illuminated the bearing of the pressure roller on the drive side. The arranged on the operating side elements, already mentioned in the description of the Figures 5 and 6 have been entered into the FIGS. 7 to 9 not drawn.

In the FIG. 7 illustrating a plan view of a printing press according to the invention, it can be seen that the mandrel 12 of the pressure roller 4 is mounted in a further lever arm 40. The mandrel 12 is rotatably mounted in at least two axially spaced, but not shown bearings. Because of these two bearings, it is possible for the purpose of sleeve replacement to hold the mandrel 12 einindig, even if the lever arm 30 is no longer in contact with the bearing 14. The user-side end of the pressure roller is thus freely accessible.

The lever arm 40 is rotatably mounted on the pin 41 in the plate 11, which may be part of the printing press frame, stored. This formed by the pivot 41 pivot axis of the lever arm 40 is aligned with the axis of rotation 31 of the lever arm 30. The lever arm 40 is movable by means of an actuator 42 which is coupled via a pivot joint 43 movable with the lever arm 40. The actuator 42 is also articulated via the hinge 44 pivotally connected to the plate 11, wherein this connection in the present embodiment comprises a holder 45 which is fixed to the plate 11. Of course, the actuator can be attached via the rotary joint directly to the plate 11.

The lever arm 40 may be acted upon analogously to the lever arm 30 with a spring force, so that the pressure roller 4 on the drive side of Counterpressure cylinder is kept away when the actuator exerts no force. The actuator 42 may be configured analogously to the actuator 32. In particular, it can be identical. Both actuators 32, 42 are preferably compressed-air-operated piston-cylinder units. LIST OF REFERENCE NUMBERS 1 printing material 2 Impression cylinder 3 press 4 pressure roller 5 6 7 8th 9 10 plate 11 plate 12 mandrel 13 shell 14 camp 15 guide rail 16 17 shell pieces 18 Window-like breakthrough 19 hand lever 20 actuator 21 groove 22 groove 30 lever arm 31 spigot 32 actuator 33 pivot point 34 pivot point 35 piston rod 36 feather 37 piston 38 cylinder 40 lever arm 41 spigot 42 actuator 43 swivel 44 swivel 45 holder F1 ... F6 inking D1 ... D6 pressure cylinder DZ1 ... DZ6 pressure zones φ Direction of rotation of the impression cylinder. 2 z Transport direction of the printing substrate 1

Claims (15)

1. Printing press (3) for printing of a panel (1), which (3) comprises of the following characteristics:

   - a central impression cylinder (2)

   - means for the advance of the panel (1) to the central impression cylinder (2),

   - a nip roll (4) for the pressing of the panel (1) to the central impression cylinder (4), and

   - several impression cylinders (D1...D6) actuated against the central impression cylinder (4)

   characterized in that
   the impression cylinder (4) is composed of an arbour (12) and at least one sleeve.
2. Printing press (3) according to claim 1,
   characterized in that
   the sleeve is locked on the arbour (12) either hydraulically or pneumatically.
3. Printing press (3) according to one of the preceding claims,
   characterized in that
   the arbour (12) can be actuated against the impression cylinder (2) by means of a cylinder (D1 ...D6) which is either applied pneumatically or hydraulically.
4. Printing press (3) according to one of the preceding claims,
   characterized in that
   the actuation path of the impression cylinder (4) is straight against the nip roll (2).
5. Printing press (3) according to one of the preceding claims,
   characterized in that
   at least one shoulder of the frame of the printing press (3) is equipped with a window-like hollow through which the sleeve can be detached.
6. Printing press (3) according to one of the preceding claims,
   characterized in that
   the actuation force of the roller can be controller preferably regulated.
7. Printing press (3) according to one of the preceding claims,
   characterized in that
   the roller is brought from a actuation position to a trimmer position by a pivoting of a roll holder preferably comprising a cylinder.
8. Printing press according to one of the preceding claims,
   characterized in that
   at each end of the nip roll an actuator is provided applying a force to the nip roll which is required for the actuation to the impression cylinder.
9. Printing press according to the preceding claim,
   characterized in that
   at each end of the nip roll a spring element is provided applying a force to the nip roll which contains at least one component which is directed away from the impression cylinder.
10. Printing press according to the preceding claim,
    characterized in that
    the force applied by the spring elements is less that the maximal applicable pressing force of the actuators.
11. Printing press according to one of the two preceding claims,
    characterized in that
    the actuators are piston cylinder units whereas the spring elements support themselves on a cylinder bottom and affect the pistons.
12. Printing press (3) according to claim 1, with a choice of several actuating roller sleeves.
13. Printing press according to the preceding claim,
    characterized in that
    the different sleeves do at least partly possess of rubber covers with different shore hardness.
14. Printing press according to one of the preceding claims,
    characterized in that
    the different sleeves do at least partly possess of coverings with different surface geometry.
15. Printing press according to one of the preceding claims,
    characterized in that
    the different sleeves do at least partly possess of different diameters.

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