Ink distributor for circulating ink supply to multiple printheads

Abstract

An ink distributor according to the invention for circulating liquid ink to a plurality of printheads, comprising an ink chamber (14) providing the ink (13), which includes a plurality of outlet openings (15) and a plurality of inlet openings (16) for the circulating ink (13), and a plurality of switchable valves (20) for closing the outlet openings (15) and inlet openings (16), is characterized in that a switching device (41) is provided for switching the valves (20), which comprises a switching head (70) movable back and forth in an axial direction (72) and pivotable about the axial direction (72), and at least one rotatable switching wheel (51). The invention advantageously enables the switching of ink valves in a simple and at the same time reliable manner. The invention is preferably used in industrial inkjet printing presses.

Description

invention

[0001] The invention relates to an ink distributor for circulating the supply of liquid ink to a plurality of printheads, having the features of the preamble of claim 1. field of technology

[0002] The invention lies in the technical field of the graphic arts industry, and therein particularly in the area of ​​industrial, i.e., highly productive and high-quality inkjet printing on flat substrates, i.e., the image-based application (jetting) of the finest droplets of liquid ink onto sheet-, web-, film-, or label-shaped printing materials, preferably made of paper, cardboard, corrugated board, plastic, metal, or composite materials, with a plurality of printheads. Specifically, the invention relates to the subfield of storing and distributing the liquid ink, in particular the circulating supply of liquid ink to printheads, i.e., with an ink feed and return. State of the art

[0003] Ink distributors for circulating liquid ink supplying a plurality of printheads are already known in industrially operated inkjet printing machines, namely ink distributors with an ink chamber providing the ink, which includes a plurality of outlet openings and a plurality of inlet openings for the circulating ink, and with a plurality of switchable valves for closing the outlet openings and inlet openings.

[0004] Stepping switches are already known in the field of industrial inkjet printing. The still unpublished patent DE102024104484, for example, reveals a stepping switch for the individual adjustment of printheads.

[0005] Manufacturers of graphic products—such as printing companies with prepress, printing, and finishing departments—constantly demand increased production speed and reliability. In inkjet printing, in particular, disruptions in the ink supply, such as leaks, can lead to costly production downtime. Furthermore, the components of such an ink supply system should be inexpensive to purchase and operate, yet function reliably over the long term. Technical task

[0006] It is therefore an object of the present invention to provide an improvement over the prior art which in particular makes it possible to switch ink valves in a simple and at the same time safe manner. Inventive solution to the problem

[0007] This problem is solved according to the invention by an ink distributor according to claim 1.

[0008] Advantageous and therefore preferred embodiments of the invention are evident from the dependent claims as well as from the description and the drawings.

[0009] An ink distributor according to the invention for circulating and supplying a plurality of printheads with liquid ink, comprising an ink chamber providing the ink, which includes a plurality of outlet openings and a plurality of inlet openings for the circulating ink, and comprising a plurality of switchable valves for closing the outlet openings and inlet openings, is characterized in that a switching device is provided for switching the valves, which comprises a switching head movable back and forth in an axial direction and pivotable about the axial direction and at least one rotatable switching wheel. Advantageous forms and effects of the invention

[0010] The invention advantageously enables the simple and safe switching of ink valves. The invention is preferably used in industrial inkjet printing presses, e.g., when printing with water-based inks.

[0011] The switching head is advantageously capable of operating a plurality of switching wheels and, in particular, of selectively rotating or switching them, thus selectively opening and closing valves. The switching head is preferably axially movable by means of a spindle and pivotable by means of a pneumatic cylinder. Further developments of the invention

[0012] Preferred embodiments of the invention (hereinafter referred to as embodiments) are described below. These can also be combined with one another, unless technically precluded.

[0013] A further development can be characterized by the fact that the switching head comprises at least one switching cam. It can be provided that the switching head comprises at least two switching cams arranged successively in the axial direction, preferably exactly two. The switching cams can be designed as tooth elements, in particular with involutes. It can be provided that the switching device comprises a drive spindle for the switching head arranged in the axial direction. It can be provided that the drive spindle is rotatable about a spindle axis. It can be provided that the switching device comprises a rotary drive for the drive spindle; this can be fixed to the frame. It can be provided that the drive spindle is arranged in a spindle housing. It can be provided that the spindle housing is pivotably mounted about a pivot axis, and thus preferably also the drive spindle; alternatively, the spindle housing can be, for example,The spindle housing may be designed to move up and down or back and forth (in the direction of the axis of the shaft with the gear). The pivot axis of the spindle housing and the spindle axis may be arranged coaxially.

[0014] A further development can be characterized by the fact that the switching wheel comprises at least two radial projections and is, for example, designed as a star wheel. It can be provided that the switching wheel comprises four radial projections. It can be provided that the projections are designed as drivers, which are arranged and positioned to engage with the switching cams. It can be provided that the drivers rotate the switching wheel by 90° in each rotation. It can be provided that the valve is opened or closed with each rotation of the switching wheel by two 90° increments.

[0015] A further development can be characterized by the fact that the switching head is pivotably mounted about the axial direction in at least two positions. It can be provided that the switching head is pivotably mounted between an active position and a passive position (back and forth). It can be provided that, in the active position, the switching head actuates at least one switching wheel when moving in the axial direction. It can be provided that, in the active position, the switching head, in particular the switching cam, is aligned with the switching wheel in the axial direction. It can be provided that, in the passive position, the switching head, in particular the switching cam, passes over at least one switching wheel when moving in the axial direction without actuating it.It may be provided that by pivoting the switching head between the active and passive positions, or vice versa, and subsequently moving the switching head axially, at least one valve is selectively opened or closed, and / or at least one valve remains selectively open or closed. It may be provided that a second actuator is present which pivots the switching head between the positions. It may be provided that the pivoting of the switching head is controlled. It may be provided that controlled pivoting is carried out using a computer. It may be provided that the computer specifies that all valves or groups of valves should be opened or closed. It may be provided that the computer specifies that valves should be selectively opened or closed.The actuator may be designed as a pneumatic cylinder; alternatively, a switchable electromagnet or a rotary drive may be provided. The actuator may move the switching head against a return spring.

[0016] A further development can be characterized by the presence of at least two shafts, with each switchable valve assigned a shaft. The valves may be arranged in pairs. Each pair may be assigned a common shaft. The switching wheel may be arranged on a shaft, particularly at the end. A switching wheel may be arranged on each shaft. Each shaft may be assigned a detent. The detent may be designed to interact with a detent spring or a pair of detent springs; alternatively, spring-loaded pressure pieces may be provided.

[0017] A further development can be characterized by the fact that the axial direction runs parallel to a longitudinal direction of the ink chamber. It may be provided that the waves are arranged perpendicular to the axial direction.

[0018] A further development may be characterized by the fact that the valves are arranged in the ink chamber. It may be provided that the valves can be switched without contact. It may be provided that the valves can be switched magnetically. It may be provided that each valve includes or forms at least one magnet. It may be provided that each shaft includes or forms at least one magnet.

[0019] The technical features and combinations of features disclosed in the above sections Technical Field, Invention and Further Developments, as well as in the following section Exemplary Embodiments, represent – ​​in any combination with one another – further advantageous developments of the invention. Exemplary embodiments of the invention and figures

[0020] The Fig. Figures 1 to 6 show preferred embodiments of the invention and its further developments. Corresponding features are identified in the figures by the same reference numerals. For clarity, some reference numerals that are repeated in the figures have been omitted. Fig. Figure 1 shows a sectional view of a preferred embodiment of an ink distributor according to the invention. Fig. Figure 2 shows the preferred embodiment of the Fig. 1 with a changed position of the valves. Fig. Figure 3 shows a perspective view of a preferred embodiment of an ink distributor according to the invention. Fig. Figure 4 shows a side view of a preferred embodiment of an ink distributor according to the invention. Fig. Figure 5 shows a sectional view of a preferred embodiment of an ink distributor according to the invention. Fig. Figure 6 shows a sectional view of a preferred embodiment of an ink distributor according to the invention.

[0021] In Fig. Figure 1 shows a section of an ink distributor 12 (a so-called manifold) according to the invention for the circulating distribution of ink to several printheads 2 of an industrial inkjet printing machine 1 for printing on substrate 3, in which liquid ink 13 is stored in an ink chamber 14. The ink chamber 14 has a preferably horizontal inner surface 14a, in particular a bottom 14e, and at least one side wall 14b. The ink chamber 14 can also be closed with a cover 14c. The ink chamber 14 has a longitudinal direction 14d.

[0022] Several outlet openings 15 are present on the inner surface 14a and in the base 14e, two of which are shown as examples. Ink lines 15a for the supply, i.e., the delivery of ink to the printheads, are connected to each of these outlet openings 15. Additionally, several inlet openings 16 are present, each connected to ink lines 16a for the return to the circulating ink. The inlet openings 16 are located in the two Fig. 1 and Fig. 2 are located behind the outlet openings and are therefore not visible.

[0023] Each individual ink orifice, i.e., both the outlet orifices 15 and the inlet orifices 16 for the ink 13, is equipped with a switchable valve 20. The valves 20 can be switched without contact. Two valves 20 together can form a valve pair 26: one for the supply and one for the return of the ink to the same printhead. The valves 20 of each pair 26 are located in the two Fig. 1 and Fig. They are arranged one behind the other, so only the front one is visible.

[0024] The valves 20 are designed as switchable valves 20 and in particular as shut-off valves and comprise respective valve flaps 2. The valve flaps 23 are arranged on the inner surface 14a, preferably screwed on. The valve flaps 23 can assume at least two (end) positions: In Fig. Figure 1 shows the valves 20 and the valve flaps 23 in their first positions 20a and in an open position; in Fig. 2 in a second position 20b and in a closed position.

[0025] Each valve 20 comprises a body 21, e.g. made of plastic, which is preferably attached to the inner surface 14a by means of a fastening element 22, e.g. a screw. Each valve 20 further comprises a movable valve flap 23, which is pivotable, in particular with respect to the inner surface 14a. The pivotability can be effected, as shown, by a joint 24, in particular a rigid joint, and further, in particular, by a flexible joint. A seal 25 is preferably arranged on each valve flap 23, in particular inserted into a hole in the valve flap 23. Fig. 1. The seal 25 is not in contact with the inner surface 14a and the opening 15 or 16 is accordingly released (valve open), while in Fig. 2 the seal 25 rests against the inner surface 14a and the opening 15 or 16 is closed accordingly (valve closed).

[0026] The following is provided for opening and closing the individual valves 20 or, alternatively, the pairs of valves 26. A first magnet 30, preferably a permanent magnet, is arranged on the valve flap 23, the valve 20 preferably comprising the following sequence of elements: fastening element 22, hinge 24, seal 25, and first magnet 30. Alternatively, the valve flap 23 itself can be magnetic. The first magnet 30 has a fixed polarity, with, for example, the north pole 33 pointing upwards and the south pole 34 pointing downwards. A rotatable second magnet 31, preferably also a permanent magnet, is arranged in the base 14e (below the inner surface 14a), in particular in a cylindrical bore. Two second magnets 31, i.e., a pair 32, can be assigned to the two first magnets 30 of a valve pair 26. Fig. 1 and Fig. Figure 2 shows the first magnets 30 and the second magnets 31 one after the other, so that only the front magnet is visible in each case. The second magnets 31 are rotatable, preferably by 180° increments in one direction and / or by 180° in one direction and back again, thus reversing their respective polarity. Fig. In 1, the north pole 33 points upwards and the south pole 34 downwards (polarity in the "valve open" state; first magnet 30 and second magnet 31 repel each other; magnetic opening force acts), while in Fig. 2 the north pole 33 points downwards and the south pole 34 points upwards (polarity in the state “valve closed”; first magnet 30 and second magnet 31 attract each other; magnetic closing force acts).

[0027] The rotation of the second magnets 31 can be achieved as follows: an actuator 40 can be present, which rotates each magnet 31, either directly or, for example, via a shaft. If the second magnets 31 form pairs 32, it can be provided that one actuator 40 rotates each pair 32 together and thus simultaneously (in this case, the forward and return feeds for a respective printhead open and close simultaneously). The actuator can be mechanically operated, and the control for opening and closing can be carried out via a digital computer if the circulating ink supply for a specific printhead, for a group of printheads, or for all printheads is to be activated or deactivated.

[0028] The rotation of the second magnets 31 can alternatively be effected manually, e.g. via operable levers. In this case as well, the force transmission to the valve flap 23 is magnetic and therefore contactless.

[0029] According to another alternative, the second magnets 31 are designed as electromagnets and can be switched accordingly.

[0030] Fig. Figure 3 shows an ink distributor according to the invention and the already existing features in view of the Fig. 1 and Fig. The two described valves 20 are shown, and in this illustration, the two valves 20 of each valve pair 26 are also recognizable. For the sake of clarity, details of the ink chamber 14 have been omitted. With regard to Fig. 3 and the others Fig. Sections 4 to 6 below describe the actuation of the valves 20 using the actuator 40 and using a switching device 41 for the actuator 40.

[0031] The second magnets 31 described above are preferably arranged as a pair 32 in or on a shaft 50 of the actuator 40, which is preferably rotatably mounted in a bore in the base 14e. A switching wheel 51 of the actuator 40 is arranged on the shaft 50, preferably designed as a star wheel and having several radial projections 52 (drivers or drive wings; e.g., four). Furthermore, the shaft 50 has one or more detents 53 formed on the shaft body, which interact with a detent spring 54 or with a pair of detent springs 54, such that the shaft 50 engages after each rotation by preferably 90° or 180°. The rotation of the shaft 50 causes the second magnets 31 to rotate or to reverse their polarity, thereby opening or closing the switchable valves 20 without contact.

[0032] In the Fig. Figures 4 to 6 show a screw drive 60. This includes a drive spindle 61, preferably a threaded spindle. The drive spindle 61 has a spindle axis 62. The screw drive 60 further includes a spindle housing 63, which is preferably tiltable about a pivot axis 64 and is returned to its original position by a return spring 65.

[0033] The switching device 41 comprises, in addition to the shift wheel 51(s) and the screw drive 60, several shift heads 70. Each shift head 70 has at least one shift cam 71 which, during its movement, interacts with the radial projections 52 of the shift wheel 51(s). Each shift head 70 shown here has, by way of example, a first shift cam 71a and a second shift cam 71b. The shift heads 70 can be moved back and forth together in an axial direction 72 by means of the screw drive 60.

[0034] In Fig. Figure 5 shows that the switching head 70 can assume a first (tilting) position 73, in which the switching head 70 is in a passive position. This means that the switching head 70, or rather its switching cam 71, does not come into contact with the radial projections 52 when moved in the axial direction 72. Fig.In contrast, it is evident from Figure 6 that the switching head 70 can also assume a second (tilting) position 74, in which the switching head 70 is in an active position. This means that the switching head 70, or rather its switching cam 71, comes into contact with the radial projections 52 when moving in the axial direction 72, thereby rotating the respective switching wheel 51, preferably by 90° or 180°. In this way, using a first drive 80 (preferably a rotary drive of the threaded spindle 61 for the linear movement 66 of the switching head 70) and a second drive 81 (preferably a pneumatic drive or cylinder for the tilting movement 67 of the switching head 70), and using a controlling computer 90, a valve 20 or a pair of valves 26 can be selectively opened or closed. The number of available switching heads 70 determines how many switching wheels 51 can be operated simultaneously.In the example shown, each switching head 70 has two switching cams 71, wherein each individual switching cam 71 rotates a switching wheel 51 by 90° or wherein two switching cams 71 of a switching head 70 rotate a switching wheel 51 by twice 90° and thus 180°.

[0035] It may be provided that there are as many switching heads 70 as switching wheels 51. In this case, all valves 20 or valve pairs 26 can be opened or closed simultaneously. It may also be provided that there is only one switching head 70. In this case, all valves 20 or valve pairs 26 can be opened or closed sequentially with this switching head 70. Individual valves 20 or valve pairs 26 can also be selectively opened or closed with the single switching head 70. It may also be provided that there is more than one switching head 70 but fewer switching heads 70 than switching wheels 51. Reference symbol list 1 industrial inkjet printing machine 2 printheads 3. Printing material, sheet or web 12 ink distributors (so-called manifold) 13 ink 14 ink chamber 14a Inner surface of the ink chamber 14b Side wall 14c lid 14e Floor 14d Longitudinal direction of the ink chamber 15 outlet opening(s) 15a Supply ink line, in particular hose line 16 Entrance opening 16a Return ink line, in particular hose line 20 switchable valve, in particular shut-off valve 20a first position, open position 20b second position, closed position 21 bodies 22 Fastening element 23 Valve flap (swivel) 24 Joint, especially solid body joint 25 Seal 26 valve pairs 30 first magnet 31 second magnet, especially rotatable 32 pairs of second magnets 33 North Pole 34 South Pole 40 actuator 41 Switching device 50 wave 51 Rotary gear (rotatable), in particular star gear 52 radial projections (driver wings) 53 Raste(s) 54 Detent spring or detent spring pair 60 screw gears 61 Drive spindle (threaded spindle) 62 Spindle axis 63 Spindle housing (tiltable) 64 Swivel axis 65 Return spring 66 Linear motion 67 Tilting movement 70 Switch head (linearly movable) 71 switching cams 71a first switching cam 71b second switching cam 72 Axial direction 73 First position of the switch head, passive position 74 second position of the switch head, active position 80 First drive, rotary drive (for linear movement of the switching head) 81 Second drive, pneumatic cylinder (for tilting movement of the switching head) 90 computers

Claims

[1] Ink distributor for circulating liquid ink supplying a plurality of printheads, comprising an ink chamber (14) providing the ink (13), which includes a plurality of outlet openings (15) and a plurality of inlet openings (16) for the circulating ink (13), and comprising a plurality of switchable valves (20) for closing the outlet openings (15) and inlet openings (16), characterized by , that for switching the valves (20) a switching device (41) is provided which comprises a switching head (70) movable back and forth in an axial direction (72) and pivotable about the axial direction (72) and at least one rotatable switching wheel (51). [2] Ink distributor according to claim 1, characterized by that the switching head (70) comprises at least one switching cam (71) or that the switching head (70) comprises at least two switching cams (71) arranged consecutively in the axial direction (72). [3] Ink distributor according to any of the preceding claims, characterized by , that the switching device (41) comprises a drive spindle (61) arranged in the axial direction (72) for the switching head (70). [4] Ink distributor according to claim 3, characterized by , that the drive spindle (61) is arranged in a spindle housing (63) and that the spindle housing (63) is pivotably mounted about a pivot axis (64). [5] Ink distributor according to claim 4, characterized by , that the pivot axis (64) of the spindle housing (63) and a spindle axis (62) are arranged coaxially. [6] Ink distributor according to any of the preceding claims, characterized by that the shift wheel (51) comprises at least two radial projections (52). [7] Ink distributor according to claim 6, characterized by , that the projections (52) are designed as drivers (52) which are designed and arranged to be movable by the switching cams (71). [8] Ink distributor according to any of the preceding claims, characterized by , that the switching head (70) is pivotably mounted about the axial direction (72) in at least two positions (73, 74), wherein the switching head (70) is pivotably mounted between an active position (74) and a passive position (73). [9] Ink distributor according to claim 8, characterized by , that the switching head (70) in the active position (74) is aligned with the switching wheel (51) in the axial direction (72). [10] Ink distributor according to one of the preceding claims 8 or 9, characterized by , that the switching head (70) in the passive position (73) passes at least one switching wheel (51) without actuating it when moving in the axial direction (72). [11] Ink distributor according to any one of the preceding claims 8 to 10, characterized by, that by pivoting the switching head (70) between the active position (74) and the passive position (73) or vice versa and the subsequent movement of the switching head (70) in the axial direction (72) at least one valve (20) is selectively opened or closed and / or at least one valve (20) remains selectively in the open or closed state. [12] Ink distributor according to any of the preceding claims, characterized by , that a second drive (82) is present which pivots the switching head (70) between the positions (73, 74). [13] Ink distributor according to any of the preceding claims, characterized by , that the valves (20) are arranged in the ink chamber (14). [14] Ink distributor according to any of the preceding claims, characterized by , that the valves (20) can be switched without contact.

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