Printing unit with positioning system

Abstract

The present invention relates to a printing unit comprising a chassis having a first side frame portion (31a) and a second side frame portion configured to accommodate a first distal end portion and a second distal end portion of an anilox cylinder, respectively. The first distal end portion and the second distal end portion of the anilox cylinder comprise a connecting portion, and the printing unit further comprises a positioning system (42) configured to position the connecting portion at a predetermined angular position. The predetermined angular position allows for withdrawal of the anilox cylinder from the printing unit. The positioning system (42) comprises an indexing disk (44) and a linear locking arrangement (52) configured to provide rotational displacement of the connecting portion.

Description

[Technical Field]

[0001] The present invention relates to an anilox positioning system for a flexographic printing module. Such an anilox positioning system can be used in converting machines such as flexo folder-gluer machines, rotary die-cut machines, or flexographic printing presses. [Background technology]

[0002] Converting machines can be used to print sheets or produce packaging products such as blanks or boxes made from paper, cardboard, or plastic. Two common types of converting machines are rotary die cutters and folder-gluers. These types of machines can be configured to produce blanks in the form of flat-pack boxes or folding boxes. Converting machines in the form of printing presses can be configured to print sheets such as corrugated board.

[0003] These machines may comprise a printing section including a plurality of flexographic printing units arranged one after the other in the transport direction, each of which may be configured to print with a different ink.

[0004] Such printing units include an anilox cylinder with an open-cell structure around its periphery. These cells absorb ink from the doctor blade chamber and transfer it to the printing plate on the printing cylinder. Because the cell structure is related to the resolution and amount of ink deposited on the blank, different types of blanks often require different anilox cylinders.

[0005] For example, anilox cylinders used for printing involving full tone areas, i.e., large areas that are evenly coated with ink, are not suitable for finer printing work that does not involve significant full tone areas.

[0006] EP 3927551 discloses a mobile handling carriage and system designed to extract an anilox cylinder from a flexographic printing assembly, transfer the extracted anilox cylinder to a storage location, and replace the extracted printing cylinder with a new anilox cylinder.

[0007] To withdraw the anilox cylinder, it is necessary to position the anilox cylinder in the release position and remove it from the drive means. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] European Patent No. 3927551 Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the prior art, it is an object of the present invention to provide a printing unit positioning system that allows for full or partial automatic extension of the anilox cylinder. It is therefore desirable to provide a consistent and accurate orientation of the anilox cylinder in its released position. [Means for solving the problem]

[0010] This object is solved by a printing unit as claimed in claim 1.

[0011] According to a first aspect of the present invention there is provided a printing unit comprising a chassis having first and second side frame portions configured to receive first and second distal end portions, respectively, of an anilox cylinder; the first and second distal end portions of the anilox cylinder comprise connecting portions, and the printing unit further comprises a positioning system configured to position the connecting portions at predetermined angular positions that allow withdrawal of the anilox cylinder from the printing unit; The positioning system includes an indexing disk and a linear locking arrangement, the indexing disk configured to move in unison with a coupling portion of the anilox cylinder and including at least one engagement surface, and the linear locking arrangement including a movable locking member configured to engage the engagement surface and provide rotational displacement of the indexing disk.

[0012] The present invention is based on the recognition that a mechanical stop can be provided so that the locked position of the anilox disc is reproducible.

[0013] In one embodiment, the first positioning device is configured to provide a first rotational displacement of the coupling portion, and the positioning system is configured to provide a second and subsequent rotational displacement of the coupling portion.

[0014] In one embodiment, the first positioning device is configured to provide a first rotational displacement of the coupling portion, and the positioning system is configured to provide a second and subsequent rotational displacement of the coupling portion.

[0015] The first positioning device may be a drive system for the anilox roll.

[0016] In one embodiment, the indexing disc includes a first peripheral notch forming an engagement surface, and the movable locking member is configured to abut the first peripheral notch and provide rotational displacement of the indexing disc.

[0017] In one embodiment, the blocking surface is coupled to at least one side frame portion of the chassis, and the movable locking member comprises: a first contact surface configured to engage an engagement surface of the indexing disc to provide rotational displacement of the indexing disc; a second contact surface configured to abut the blocking surface; Equipped with The rotational displacement of the indexing disc is configured to stop when the second contact surface of the movable locking member abuts the blocking surface.

[0018] In one embodiment, the positioning system further comprises a detection system configured to detect an angular position of the indexing disc, the detection system comprising a sensor and a detection element, the detection element being arranged on or in the indexing disc, the detection system being configured to provide a control signal to a control unit of the positioning system and to displace the movable locking member upon detection of a predetermined angular position of the detection element by the sensor to provide a second rotational displacement of the coupling portion.

[0019] In one embodiment, the sensing element is a notch in the indexing disk.

[0020] In one embodiment, the positioning system includes a piston actuator attached to the side frame portion, with the movable locking member attached to a distal end of a piston rod of the piston actuator.

[0021] In one embodiment, the sensing system is configured to provide a start signal to the piston actuator when the sensing system sends a control signal.

[0022] In one embodiment, the movable locking member comprises a slider slidably coupled to a guide rail attached to the side portion.

[0023] In one embodiment, the movable locking member has a roller configured to contact the indexing disc.

[0024] The present invention will now be described with reference to the accompanying drawings, in which like features are given the same reference numerals, and in which: [Brief explanation of the drawings]

[0025] [Figure 1a] FIG. 2 is a schematic diagram of a printing section. [Figure 1b] FIG. 2 is a schematic diagram of a printing unit. [Figure 2] FIG. 1 is a schematic perspective view of a printing section with an integrated anilox changing carriage. [Figure 3] FIG. 2 is a schematic cross-sectional view of a connecting portion of an anilox cylinder. [Figure 4] FIG. 2 is a schematic perspective view of a side portion of the printing unit chassis. [Figure 5] FIG. 1 is a schematic cross-sectional view of a positioning system, in accordance with an embodiment of the present invention; [Figure 6] FIG. 1 is a schematic cross-sectional view of a positioning system in an extended position, in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention can be used with several types of printing and converting machines, such as flexo folder-gluer machines or rotary die-cutter machines.

[0027] 1a shows a printing section 2 of a converting machine, which comprises a number of flexographic printing units 6 arranged one after the other in the transport direction T.

[0028] The feeding module 4 is located at the entrance to the printing section 2. The feeding module 4 is configured to feed sheet substrates 5 one by one in a conveying direction T. The sheet substrates 5 are rectangular or square sheets made of cardboard or paperboard, plastic, or a combination thereof.

[0029] 1b shows a schematic diagram of an example of a printing unit 6. The printing unit 6 comprises a flexographic printing assembly 8 including a printing cylinder 10 configured to carry a printing plate, a counter cylinder 12, an anilox cylinder 14, and a doctor blade chamber 16. The printing unit 6 may further comprise a parking station 18 for unused anilox cylinders 14'. The parking station 18 is preferably disposed vertically below the flexographic printing assembly 8. The parking station 18 comprises supports for supporting the ends of the anilox cylinders 14'.

[0030] The main anilox storage station 20 may also be located below the feeding module 4. The main storage station 20 may have a support similar to that of the printing unit 6. The main storage station 20 may have a larger storage capacity than the holding station 18.

[0031] As shown in Figure 2, the printing section 2 can incorporate a carriage 22 for handling the anilox cylinders 14. The carriage 22 is configured to automatically collect, exchange, and move the anilox cylinders 14 between the flexographic printing assembly 8, the holding station 18, and the main storage station 20.

[0032] The carriage 22 is movable in a horizontal plane in the transport direction T and is displaceable downstream and upstream in the transport direction T from the flexographic printing unit 6 to the main storage station 20 .

[0033] The carriage 22 comprises a chassis, a support surface and one or more gripping members. The carriage 22 is movable along a guide system comprising rails 24 extending in the conveying direction T. Such a carriage and guide system is disclosed in EP 3927551.

[0034] 2 to 4, the printing unit 6 includes a chassis 28 to which the flexographic printing assembly 8 is mounted. First and second distal end portions 30a, 30b of the anilox cylinder 14 are housed in first and second side portions 31a, 31b of the chassis 28, respectively.

[0035] The first and second distal end portions 30a, 30b of the anilox cylinder 14 each include a connecting portion 34, a bearing 36, and a guide bracket 38.

[0036] The coupling portion 34 enables a drive member of the printing unit 6 to drive rotationally the anilox cylinder 14. The coupling portion 34 includes a groove 35 configured to engage with a drive member M, which groove 35 is coupled to a motor.

[0037] The carriage 22 is configured to couple its gripping member to a guide bracket 38 to withdraw the anilox cylinder 14 from the printing unit 6. The guide bracket 38 has an opening configured to receive a gripping member in the form of a latch from the carriage 22. The guide bracket 38 is received in first and second guide rails 40 coupled to the side portions 31 a, 31 b of the chassis 28. The guide bracket 38 is thus slidably received in the guide rails 40. Furthermore, the guide rails 40 are configured to support the distal end portions 30 a, 30 b of the anilox cylinder 14 as the anilox cylinder 14 is withdrawn from the chassis 28.

[0038] In order to extract the anilox cylinder 14 from the chassis 28, the first and second connecting portions 34 must be positioned in the release position.

[0039] 4, 5 and 6, the printing unit 6 includes a positioning system 42 configured to position the connecting portion 34 of the anilox cylinder 14 at a predetermined angular position so that it can be withdrawn from the drive member within the printing unit 6. In this position, the groove 35 of the connecting portion 34 is positioned horizontally. This position is referred to as the release position.

[0040] The positioning system 42 is activated when the printing section 2 stops and the anilox cylinder 14 needs to be withdrawn from the printing unit 6. A drive member for the anilox cylinder 14 is coupled to the positioning system 42. In the withdrawal mode, the drive member M is configured to provide controlled rotation of the anilox cylinder 14. The drive member M may be a motor.

[0041] In accordance with the present invention, the positioning system 42 includes an indexing disk 44, a sensing arrangement 48, and a linear locking arrangement 52.

[0042] The indexing disc 44 is operatively coupled to the connecting portion 34 so that when the indexing disc 44 rotates, the connecting portion 34 performs the same rotation.

[0043] The sensing arrangement 48 comprises a sensor 49 and a sensing element 50. The sensing arrangement is configured to sense the angular position of the indexing disc 44. Upon sensing, the sensing arrangement 48 provides a control signal when the indexing disc 44 is at a predetermined angular position. The sensing arrangement 48 may comprise a magnetic or inductive sensor 49 configured to sense a sensing element 50 attached to or incorporated into the indexing disc 44. The sensing element 50 is an element that, when captured by the sensor 49, causes a change in the sensed material property. For example, the sensing element may be a magnetic element.

[0044] The indexing disc includes an engagement surface 60 configured to engage a movable locking member 62. The engagement surface 60 may be in the form of a peripheral notch 60. According to an alternative not shown, the engagement surface 60 may be in the form of an element attached to the outer surface of the indexing disc 44.

[0045] Optionally, the indexing disc 44 may include a second notch 61. The second notch 61 may be identical to the first notch 60 so that the indexing disc 44 is symmetrical about two central axes. In a preferred embodiment, the sensing element 50 of the sensor 49 is the notch 60 or 61.

[0046] The linear locking arrangement 52 is attached to the side portion 31 a of the chassis 28. The linear locking arrangement 52 includes a movable locking member 62 attached to a cylinder rod 63 of an actuator 64. The actuator 64 may be a pneumatic actuator or a hydraulic actuator. The movable locking member 62 has a first engagement portion 65 a with a shape corresponding to the shape of the notch 60 in the indexing disc 44.

[0047] The movable locking member 62 further includes a second engagement portion 65b configured to abut against a fixed blocking surface 66. The fixed blocking surface 66 is attached to the side portion 31a of the chassis .

[0048] The second engagement portion 65b has a shape that corresponds to the blocking surface 66. In the illustrated embodiment, the blocking surface 66 may be square, and the movable locking member 62 has a corresponding square cutout.

[0049] The movable locking member 62 may include a roller 67 at its distal end. The roller 67 allows relative movement between the movable locking member 62 and the indexing disc 44.

[0050] The linear locking arrangement 52 may further include a guide rail 70 attached to the side portion 31 a of the chassis 28. The movable locking member 62 includes a corresponding slider 71 received in the guide rail 70. In this way, the movable locking member 62 is guided and its movement is limited.

[0051] 5 and 6, the movable locking member 62 is consequently movable between a retracted position A and an extended position B. When the movable locking member 62 is in the extended position, the indexing disc 44 and the connecting portion 34 are locked against further rotation. The extended position of the movable locking member 62 corresponds to the release position of the anilox cylinder 14. Thus, when the movable locking member 62 is in the extended position, the connecting portion 34 of the anilox cylinder 14 is positioned at an angle that allows horizontal withdrawal of the anilox cylinder from the printing unit 6.

[0052] The sensing arrangement 48 is configured to detect the presence of a sensing element 50 in (or on) the indexing disk 44. Alternatively, and preferably, the sensor 49 may be configured to sense the passage of the notch 60 or 61 as the indexing disk 44 rotates. This sensing position is an angular position of the indexing disk 44 and may be referred to as the "middle position," where the indexing disk 44 is closer to the release position.

[0053] The positioning system 42 further comprises a control unit 80 configured to receive a control signal from the sensing arrangement 48 and to initiate the displacement of the movable locking element 62 .

[0054] In the intermediate position, the movable locking member 62 moves from the retracted position toward the extended position. Before reaching the extended position, the movable locking member 62 enters the notch 60 in the indexing disc 44, and the first engagement portion 65a contacts the notch in the indexing disc 44.

[0055] The movable locking member 62 and the notch have cooperating geometric shapes. The notch can have a rectangular shape, and the movable locking member 62 can have a shape that allows the movable locking member 62 to contact both sides 60 a, 60 b of the notch.

[0056] Thereafter, the movable locking member 62 is forced into the notch 60 until the second engagement portion 65 b of the movable locking member 62 contacts the fixed blocking surface 66 .

[0057] The drive member thus performs a first rotational displacement of the indexing disc 44 until it reaches an intermediate position.

[0058] The drive member may be the same drive mechanism configured to rotate the anilox cylinder 14 during operation. However, when providing positioning motion, the drive member effects a slower, more controlled rotation of the indexing disc 44.

[0059] A subsequent second rotational movement is provided by the movable locking member 62 until the second engagement surface 65b of the movable locking member 62 engages the fixed blocking surface 66. The movable locking member 62 provides the rotational displacement while simultaneously locking the indexing disc 44 against the blocking element 66. [Explanation of symbols]

[0060] 6 Printing Unit 14 Anilox Cylinder 28 chassis 30a first distal end portion 30b second distal end portion 31a first side frame portion 31b second side frame part 34 Connecting part 42 Positioning System 52 Linear lock configuration

Claims

1. A printing unit (6) comprising a chassis (28) having first and second side frame portions (31a, 31b), the side frame portions are configured to receive a first distal end portion (30a) and a second distal end portion (30b) of an anilox cylinder (14), respectively, the first and second distal end portions of the anilox cylinder including respective connecting portions (34); the printing unit further comprising a positioning system (42) configured to position the connecting portion (34) at a predetermined angular position that allows withdrawal of the anilox cylinder from the printing unit; The positioning system comprises an indexing disc (44) and a linear locking arrangement (52); the indexing disk (44) is configured to move in unison with the connecting portion (34) of the anilox cylinder (14), and further comprises at least one engagement surface (60); The linear locking arrangement (52) comprises a movable locking member (62) configured to engage the engagement surface (60) and provide rotational displacement of the indexing disc (44).

2. 2. The printing unit of claim 1, wherein a first positioning device is configured to provide a first rotational displacement of the connecting portion, and the positioning system is configured to provide a second and subsequent rotational displacement of the connecting portion.

3. 3. A printing unit according to claim 2, wherein said first positioning device comprises a drive member (M) of said anilox cylinder (14).

4. 4. A printing unit according to claim 1, wherein the indexing disc includes a first peripheral notch (60) forming the engagement surface, and the movable locking member (62) is configured to abut against the first peripheral notch and provide rotational displacement of the indexing disc.

5. A blocking surface (66) is coupled to at least one side frame portion (31 a) of the chassis, and the movable locking member (62) a first contact surface (65a) configured to engage with said engagement surface (60) of said indexing disc (44) to provide a rotational displacement of said indexing disc (44); a second contact surface (65b) adapted to abut against said blocking surface (66); Equipped with 5. A printing unit according to claim 1, wherein the rotational displacement of the indexing disc (44) is configured to stop when the second contact surface (65b) of the movable locking member abuts against the blocking surface (66).

6. 3. A printing unit according to claim 2 in combination with any one of the preceding claims, wherein the positioning system (42) further comprises a detection system (48) configured to detect an angular position of the indexing disc (44), the detection system comprising a sensor (49) and a detection element (50, 60, 61), the detection element being arranged on or in the indexing disc (44), the detection system being configured to supply a control signal to a control unit (80) of the positioning system (42) to displace the movable locking member and provide a second rotational displacement of the coupling part upon detection by the sensor (49) of a predetermined angular position of the detection element (50, 60, 61).

7. 7. A printing unit according to claim 6, wherein said detection elements are notches (60, 61) in said indexing disc (44).

8. 8. A printing unit according to claim 1, wherein the positioning system (42) comprises a piston actuator (64) mounted on one side frame portion (31 a), and the movable locking member (62) is mounted on a distal end of a piston rod of the piston actuator (64).

9. 9. A printing unit according to claim 6 and 8, wherein the sensing system is configured to provide a start signal to the piston actuator when the sensing system issues the control signal.

10. 10. A printing unit according to claim 9, wherein the movable locking member comprises a slider (71) slidably coupled to a guide rail (70) attached to the side frame portion (31a).

11. 11. A printing unit according to any preceding claim, wherein the movable locking member comprises a roller (67) arranged to contact the indexing disc (44).

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