PRINTING DEVICE FOR A COUPLING MACHINE

Abstract

Disclosed is a flexographic printing device for a laminating machine, including at least one pair of shoulders mounted on a trolley frame, a blade chamber for containing printing ink; an Anilox roller that rotates in contact with the printing ink, a print roller holding a printing cliché that rotates in contact with the Anilox roller and a counter-pressure roller that rotates in contact with the cliché held by the print roller, wherein at least the Anilox roller and the print roller are supported by respective supports that can slide with respect to the shoulders in a direction substantially orthogonal to their axes, the printing device also including at least one first motor for rotating the Anilox roller, at least one second motor for rotating the print roller and possibly a third motor for rotating the counter-pressure roller.

Claims

1. A movable-type flexographic printing device, adapted to be used in association with a laminating machine, comprising at least: a support structure that includes at least one pair of shoulders mounted on a trolley frame; a blade chamber that defines a tank for containing printing ink; an Anilox roller, the surface of which is in communication with the tank of the blade chamber so that, rotating around the Anilox roller's axis, a quantity of ink remains adhering to said surface; a print roller, adapted to hold a printing cliché, which can rotate around its own axis in contact with the Anilox roller so that a layer of ink is deposited onto the surface of said cliché; and a counter-pressure roller that can rotate in contact with the cliché held by the print roller; wherein at least the Anilox roller and the print roller are supported at the ends by respective supports that can slide with respect to the shoulders of the support structure in a direction substantially orthogonal to the axes of said Anilox and print rollers, the printing device also comprising at least one first motor capable of rotating the Anilox roller, and at least one second motor capable of rotating the print roller.

2. The printing device according to claim 1, wherein said print roller comprises a cliché-holder cylinder supported at the ends by two shafts where at least one first shaft is stably mounted on a respective support and is movingly coupled with the cliché-holder cylinder and wherein the second motor, which rotates the print roller, comprises a ring rotor fitted directly onto said first shaft, and a ring stator, which wraps around said rotor, in one piece with the sliding support.

3. The printing device according to claim 2, wherein the cliché-holder cylinder has an internal cavity, and wherein there is a passage in the first shaft, which extends parallel to the axis of the print roller, a first end of which ends at the free end of said first shaft, and a second end of which, opposite the first end, communicates with the cavity of the cliché-holder cylinder, said first passage end being connectable to a source of compressed air.

4. The printing device according to claim 1, wherein the print roller is mounted on the sliding supports so as to be able to translate axially, the printing device also comprising a position adjustment system adapted to control the movement of the print roller along said direction of axial translation.

5. The printing device according to claim 4, wherein said position adjustment system comprises a motor connected to a control member movable along a direction parallel to the axis of the print roller, said control member engaging an insert in one piece with or made in the first shaft of the print roller to move it along said direction of axial translation.

6. The printing device according to claim 4, wherein the active part of the rotor of the second motor that rotates the print roller, has a length, in the axial direction, greater than that of the stator, by a length at least equal to the maximum axial movement that said print roller can make, so that following said axial movement the maximum torque of the second motor remains substantially unchanged.

7. The printing device according to claim 1, wherein said sliding supports are connected to the respective shoulders, each by means of a pair of sliding guides.

8. The printing device of claim 1, further comprising a third motor capable of rotating the counter-pressure roller.

9. The printing device according to claim 2, wherein the print roller is mounted on the sliding supports so as to be able to translate axially, the printing device also comprising a position adjustment system adapted to control the movement of the print roller along said direction of axial translation.

10. The printing device according to claim 3, wherein the print roller is mounted on the sliding supports so as to be able to translate axially, the printing device also comprising a position adjustment system adapted to control the movement of the print roller along said direction of axial translation.

11. The printing device according to claim 8, wherein the print roller is mounted on the sliding supports so as to be able to translate axially, the printing device also comprising a position adjustment system adapted to control the movement of the print roller along said direction of axial translation.

12. The printing device according to claim 9, wherein said position adjustment system comprises a motor connected to a control member movable along a direction parallel to the axis of the print roller, said control member engaging an insert in one piece with or made in the first shaft of the print roller to move it along said direction of axial translation.

13. The printing device according to claim 10, wherein said position adjustment system comprises a motor connected to a control member movable along a direction parallel to the axis of the print roller, said control member engaging an insert in one piece with or made in the first shaft of the print roller to move it along said direction of axial translation.

14. The printing device according to claim 11, wherein said position adjustment system comprises a motor connected to a control member movable along a direction parallel to the axis of the print roller, said control member engaging an insert in one piece with or made in the first shaft of the print roller to move it along said direction of axial translation.

15. The printing device according to claim 2, wherein said sliding supports are connected to the respective shoulders, each by means of a pair of sliding guides.

16. The printing device according to claim 3, wherein said sliding supports are connected to the respective shoulders, each by means of a pair of sliding guides.

17. The printing device according to claim 4, wherein said sliding supports are connected to the respective shoulders, each by means of a pair of sliding guides.

18. The printing device according to claim 5, wherein said sliding supports are connected to the respective shoulders, each by means of a pair of sliding guides.

19. The printing device according to claim 6, wherein said sliding supports are connected to the respective shoulders, each by means of a pair of sliding guides.

20. The printing device according to claim 8, wherein said sliding supports are connected to the respective shoulders, each by means of a pair of sliding guides.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Further features and advantages of the present invention will be more apparent from the description of a preferred but not exclusive example of embodiment of an apparatus for producing a multi-layer film, as illustrated in the accompanying figures, wherein:

[0059] FIGS. 1a and 1b are two perspective views of the printing device according to the present invention;

[0060] FIG. 2 is a view of the device according to the invention, sectioned along a vertical plane orthogonal to the axes of the rollers;

[0061] FIGS. 3a and 3b are two side views, respectively from opposite sides, of the device according to the present invention;

[0062] FIGS. 4a and 4b are two side views, respectively of opposite sides, of the device of FIGS. 3a and 3b partially disassembled;

[0063] FIG. 5 is a view of the device according to the invention, sectioned along a vertical plane passing through the axis of rotation of the print roller;

[0064] FIG. 6 is a detail view of the print roller, sectioned along a vertical plane passing through its axis of rotation;

[0065] FIG. 7 is a schematic side view of a laminating machine equipped with the printing device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] With reference to the accompanying FIGS. 1a and 1b, the number 1 indicates as a whole a printing device of the type adapted to be used preferably, but not exclusively, in association with a laminating machine 100 or the like, as illustrated in FIG. 7.

[0067] The device essentially comprises a support structure 10 with a pair of shoulders 10a, 10b supported by a trolley frame 11 equipped with wheels 12. A blade 13, an Anilox roller 14, a print roller 30 and a counter-pressure roller 15 are mounted on the shoulders 10a, 10b.

[0068] In the variant illustrated, the counter-pressure roller 15 is mounted to be able to rotate about its axis Xp directly on the shoulders 10a, 10b. The counter-pressure roller is rotated by a motor, by means of a belt transmission, not illustrated in the figures. The position of the counter-pressure roller with respect to the shoulders 10a, 10b is therefore substantially fixed.

[0069] The Anilox roller 14 is instead supported at its ends, so that it can rotate about its axis Xa, by a pair of first supports 16a, 16b. The blade chamber 13 is preferably also mounted on the first supports 16a, 16b.

[0070] Said blade chamber 13 defines a compartment 17 that acts as tank for containing printing ink. The compartment 17 has at least one slot shaped opening 17a, facing the Anilox roller 14, which places the surface thereof in communication with the ink in the compartment 17.

[0071] Said opening 17a is delimited transversely by at least one blade 18, preferably by a pair of blades 18. The Anilox roller 14 is arranged so as to rotate substantially in contact with said blades 18, which have the function of distributing the ink uniformly in the micro cavities or cells made on its surface. The blade chamber 13 is preferably movingly mounted on the first supports 16a, 16b so that it can be moved away from or toward the Anilox roller 14.

[0072] The Anilox roller 14 is rotated by a first motor 19, preferably of brushless type, through a transmission comprising a belt 20, a first pulley connected to the first motor 19, not visible in the figures, and a second pulley 21 connected to the Anilox roller 14.

[0073] The first supports 16a, 16b, are mounted sliding on the shoulders 10a, 10b along a direction substantially horizontal and perpendicular to the axis Xa of the Anilox roller 14. More in detail, said supports 16a, 16b are each provided with at least two, and preferably at least three, slides 22a, 22b sliding on respective guides 23a, 23b fixed to the shoulders 10a, 10b.

[0074] The movement of the first supports 16a, 16b is controlled by a pair of motors 24, each acting on one of the supports by means of a transmission. In the variant illustrated, said transmission comprises a first pulley 25 connected to the shaft of the motor 24, a belt 26, a second pulley 27 and a recirculating ball screw 28, moved by the second pulley 27, which engages a nut mounted on the support 16a, 16b.

[0075] The print roller 30 is interposed between the Anilox roller 14 and the counter-pressure roller 15. In a similar manner to the Anilox roller 14, the print roller is also supported at the ends by a pair of second supports 31a, 31b mounted sliding on the shoulders 10a, 10b. In the variant illustrated, each support is provided with at least two, and preferably at least three, slides 29a, 29b that slide on the same guides 23b, 23b as the first supports 16a, 16b.

[0076] The print roller 30 comprises a cliché-holder cylinder 32 (hereinafter also simply “cylinder 32”), preferably hollow inside, with two end shafts 33, 40. One of said shafts, defined here as second shaft 33, is in one piece with the cliché-holder cylinder 32. The other shaft, defined as first shaft 40, can instead be coupled to the cylinder 32.

[0077] This construction solution allows the first shaft to be shaped in the most convenient way and at the same time makes it possible to connect/fix certain components thereto, during assembly of the machinery, before it is coupled to the rest of the cylinder.

[0078] More in detail, the cylinder 32 comprises a coupling portion 32a with a seat 32b adapted to accommodate an end portion of 42 of the first shaft. Coupling between the parts typically takes place by means of a shrink disc or other systems by means of which said parts, shaft 40 and cylinder 32, become one piece both in rotation and axially (FIGS. 5 and 6).

[0079] The print roller 30, and more precisely its shafts 33, 40, are mounted on the respective supports 31a, 31b by means of flanges 34a, 34b that allow said print roller 30 both to rotate around its axis Xs and to translate along said axis for a travel of a few millimetres, typically from 10 mm to 20 mm.

[0080] To allow the axial movement of the shafts 33, 40, said flanges are preferably equipped with rolling means, such as radial roller bearings.

[0081] This movement is managed by a position adjustment system comprising a motor 35 which, by means of a transmission 36, operates a control member 37 movable along a direction parallel to the axis Xs of the print roller 30.

[0082] According to a preferred variant, the transmission 36 comprises a pulley 36b, connected to the motor 35 by means of a belt 36a, which rotates a shaft 36c arranged with its axis parallel to the axis Xs. Said shaft 36c comprises a threaded portion 36c′ that engages a lead screw 36d in one piece with a slider 36e sliding along the axis of the shaft 36c. Said threaded portion 36c′ of the shaft 36c and the lead screw 36d are preferably of recirculating ball type.

[0083] The slider 36e preferably has a hollow cylindrical shape and is slidingly coupled to a cylindrical support 36f fixed in one piece to one of the sliding supports 31a, 31b of the print roller 30, in particular to the support 31a in the example in the figures.

[0084] The slider 36e is in turn connected to the control member 37.

[0085] Said control member 37 is adapted to engage an insert 43 in one piece with, and which projects radially from, the first shaft 40 of the print roller 30. In a preferred variant, said insert 43 is disc shaped, preferably substantially cylindrical. Said insert 43 can be in one piece with the first shaft 40 or made in it, as in the example illustrated.

[0086] The moving member 37 is preferably in the shape of a cradle, a jaw or the like that at least partly surrounds the insert 43. For example, the moving member can comprise a body with a circular shaped sector in which a housing 37a to accommodate the insert 43 is made. Rotation of the motor 35 in one direction or the other causes the movement of the slider 36e, which drives the control member 37 in a direction parallel to the axis Xs which, in turn, rests on the insert 43 to move the first shaft 40 and the rest of the print roller 30 along the axis Xs.

[0087] The moving member 37 is preferably provided with contact elements 37b in the form of a wheel, which remain substantially in contact with the outer surfaces of the insert 43, allowing it to rotate freely.

[0088] The longitudinal movement of the print roller, or of the supports 31a, 31b, is controlled by a pair of motors 38, each acting on one of the supports by means of a transmission. Said transmission, similarly to the Anilox roller 14, comprises a first pulley 38a connected to the shaft of the motor 38, a belt 38b, a second pulley 38c and a recirculating ball screw 39, moved by the second pulley 38c, which engages the nut, not shown in the figure, mounted on the supports 31a, 31b.

[0089] According to a preferred variant, the first shaft 40 has an internal passage 45 passing through it completely from a first free end 41 to the opposite end 42, i.e., the end connected to the cliché-holder cylinder 32.

[0090] Said passage 45 allows the internal cavity 32c of the cliché-holder cylinder to communicate with a source of compressed air. Advantageously, said source of air can be connected by means of a connector 44 fixed to the end of the passage 45 that ends on the free end 42 of the first shaft. As mentioned above, the air introduced into the cavity 32c of the cliché-holder cylinder 32 flows out through holes that pass through the surface of the cylinder, not visible in the figures, to create an air cushion that facilitates sliding of the cliché-holder sleeve.

[0091] The print roller 30 is rotated by an electric motor, indicated as a whole with 50. In accordance with a preferred embodiment of the invention, said motor 50 comprises a ring rotor 51 fitted directly onto the first shaft 41 and a ring stator 52, in one piece with the sliding support 31a of the print roller 30, arranged around the rotor 51. The motor is preferably a permanent magnet motor, with the permanent magnets 51b held by the rotor 51. Instead, the stator 52 holds the windings 52a of the motor. Typically, the motor 50 is a torque motor. In fact, this type of motor can be fitted directly onto the first shaft 40 without the need for transmission members or connection elements, with the aforementioned advantages in relation to precision of movement and absence of vibrations. In addition to this, positioning of the motor in an area at a distance from the end of the shaft, allows, as in the case of the invention, this end 41 to be uncovered and made accessible, for connection of the source of air as described above.

[0092] Moreover, this type of motor makes it possible to limit the overall axial dimensions and, consequently, the length of the first shaft 40 that extends laterally from the shoulders 10a, 10b of the device.

[0093] The stator 52 is fixed to the sliding support 31a by means of a flange 53, which preferably also acts as a cover for the control member 37 that controls the axial translation movement of the first shaft 40.

[0094] The rotor 51 is mechanically released from the stator 52 and from the support flange 53 so as to be able to move along its rotation axis, coincident with the axis Xs, driven by the first shaft 40.

[0095] FIG. 7 illustrates a laminating machine 100 in which the printing device according to the invention is installed. Typically, the printing device is positioned in the area of the laminating machine that is usually occupied by the glue spreading unit (not illustrated) when the machine operates to laminate layers of film. In fact, when it is necessary to carry out reprinting on the film, laminated or to be laminated, this spreading unit can be temporarily removed and the printing device 1 positioned in its place.

[0096] In this way it is possible to make use of components already present on the laminating machine, such as winders and unwinders, guide rollers, tensioners, motors, sensors, etc.

[0097] The invention has been described purely for non-limiting illustrative purposes, according to some preferred embodiments. The person skilled in the art may find many other embodiments and variants, all falling within the scope of protection of the appended claims.