IT202100011768A1 - INKJET DIGITAL PRINTING MACHINE FOR PRINTING CYLINDRICAL MEDIA - Google Patents

Description

DESCRIPTION

The present invention relates to an inkjet digital printing machine for printing cylindrical supports.

In industrial applications, a limitation of inkjet technology? the speed? linear printing heads: these high-tech products guarantee a printable surface in the unit? of time that often ? incompatible with the expectations of current installations.

Especially in the mass production of cylindrical packaging, such as beverage cans, deodorant cans or plastic bottles, both rigid and flexible, the capacity? of printable surface guaranteed by the heads available on the market, often not? appropriate.

For example, a modern 330 ml can production line (66 mm diameter) produces 3000 pieces/min, corresponding to a theoretical surface to be printed in the unit? time of 1200 meters per minute, if we assume a piece transfer time equal to the available printing time.

A normal single pass head (the most suitable technology for industrial printing)? able to print at about 50 meters/minute.

In the production of aerosol cans, the speed? ? more contained (250 pieces/min with a diameter of 66 mm, equivalent to about 100 metres/min) but not yet within the reach of the speed? of inkjet printing.

The achievement of the expected production rates pu? also be negatively affected by the complexity? of some constructive solutions adopted, which can lengthen the assembly, disassembly and replacement of some components.

In particular, the printing machines are fed by conveyor belts having cradles for housing the cylindrical supports.

The cradles are generally fixed to the conveyor through specific blocks and screws.

In case of intervention on the conveyor for maintenance or replacement of damaged cradles, the high number of pieces to manage as well as the request for specific tools for the assembly, disassembly and replacement of the cradles can? cause prolonged downtime that is not tolerable as it penalizes productivity.

The technical task proposed by the present invention is, therefore, that of realizing an ink-jet digital printing machine for printing cylindrical supports which allows the aforementioned technical drawbacks of the prior art to be eliminated.

Within the scope of this technical task, a purpose of the invention is that of creating a digital inkjet printing machine for printing cylindrical media with high productivity.

The technical task, as well as? these and other aims, according to the present invention are achieved by realizing a digital inkjet printing machine for printing cylindrical supports, characterized in that it comprises at least one printing module, a conveyor for conveying the cylindrical supports to the printing module , where the printing module comprises a rotatable table circumferentially equipped with a plurality? of support spindles of the cylindrical supports and surmounted by a plurality? of printing stations arranged along the circular path performed by the spindles when the table rotates, where the table? configured to rotate intermittently for the stationing of the cylindrical supports below the printing stations, where the spindles are configured to rotate on s? same for the printing of the cylindrical supports stationed below the printing stations, where ? provided is a pick-up manipulator of the cylindrical supports to be printed from the conveyor and a return manipulator of the printed cylindrical supports to the conveyor, where the conveyor includes a succession of housing cradles for the cylindrical supports at regular intervals, where each cradle ? formed by a single block which defines a cavity for housing the cylindrical support and the connection brackets to the conveyor.

In one embodiment of the invention said stirrups have means for quick connection to the conveyor.

In one embodiment of the invention said quick coupling means comprise elastically compliant forks.

In one embodiment of the invention said forks are configured for a shape and force connection with pins supported by the conveyor. The present invention also discloses an inkjet digital printing machine for printing cylindrical supports, characterized in that it comprises an electronic controller, at least two printing modules, a conveyor for conveying the cylindrical supports to the two printing modules, where each printing module comprises a rotatable table circumferentially equipped with a plurality? of support spindles of the cylindrical supports and surmounted by a plurality? of printing stations arranged along the circular path performed by the spindles when the table rotates, where the table? configured to rotate intermittently for the stationing of the cylindrical supports below the printing stations, where the spindles are configured to rotate on s? same for the printing of the cylindrical supports stationed below the printing stations, where for each printing module ? provided is a pick-up manipulator of the cylindrical supports to be printed from the conveyor, and a return manipulator of the printed cylindrical supports to the conveyor, where the conveyor comprises a succession of housing cradles for the cylindrical supports at regular intervals, where the electronic controller ? programmed for a mode? of work in parallel of the printing modules in which the capacity? overall productivity of the printing machine? equal to the sum of the capacity? production of individual printing modules.

In one embodiment of the invention, when n operative printing modules are provided, with n?2, the cradles of the conveyor are divided into n groups of cradles, in each of the n groups the cradles are spaced apart from each other by n steps, and for each of the n operative printing modules the corresponding picking and redelivery manipulators are associated with a corresponding one of the n groups of cradles for picking up and returning the cylindrical supports present therein.

In one embodiment of the invention, the electronic controller ? programmed to keep the capacity unchanged? productivity of the operational printing modules by adjusting the speed? of advancement of the conveyor as the number of operating printing modules varies.

Other characteristics of the present invention are also defined in the subsequent claims.

According to the invention various printing modules are advantageously used connected to each other by a conveying conveyor and configured to work in parallel.

The cylindrical supports move on the conveyor in continuous movement, at the speed? set by container production line.

Advantageously, if a printing module stops due to any technical or production problem, production does not stop, but can continue at a speed? reduced, to the extent of the missing contribution to productivity? generated by the single printing module in stop.

This function allows you to complete a programmed production lot, even if at speed? reduced.

The particular constructive choice for the cradles, which allows their rapid assembly and disassembly without specific work tools, amplifies the advantage in terms of greater productivity? of the machine why? limits planned and unforeseen machine downtime to a minimum.

Further characteristics and advantages of the invention will become more evident from the description of a preferred but not exclusive embodiment of the digital inkjet printing machine for printing cylindrical supports according to the invention , illustrated by way of example and not in limitation in the attached drawings , in which:

Figure 1 shows a top plan view of a printing machine with two printing modules;

Figure 2 shows a side elevation view of a printing module;

figures 3A and 3B are lateral elevation views and axonometric views of the area of the printing module where the shuttle operates;

figures 4A, 4B and 4C are frontal, axonometric and lateral elevation views, respectively, of a cradle of the conveyor;

Figure 5 is an axonometric view of a section of the conveyor.

With reference to the cited figures, a digital inkjet printing machine for printing cylindrical supports is shown, indicated as a whole with the reference number 1.

The cylindrical supports 2a, 2b can be for various purposes, for example, food cans or cans for deodorants, detergents, etc.

Does the machine 1 comprise one or preferably two or more? printing modules (two printing modules 3a, 3b in the case shown by way of example), and a conveyor 4 for conveying the cylindrical supports 2a, 2b to the printing modules 3a, 3b.

Each printing module 3a, 3b comprises a rotatable table 5 circumferentially equipped with a plurality of of mandrels 6 for supporting the cylindrical supports 2a, 2b.

Table 5? surmounted by a plurality? of printing stations 7 a, 7 b.

Each printing station 7a, 7b has one or more? print heads 8.

The table 5 rotates for the sequential transport of cylindrical supports 2 a, 2 b through the printing stations 7 a, 7 b arranged along the circular path performed by the mandrels 6.

The table 5 has a vertical axis of rotation L and the mandrels 6 are positioned at a defined angular spacing pitch, in particular constant, around the vertical axis of rotation L of the table 5.

Each spindle 6 has an axis M oriented radially with respect to the vertical axis of rotation L of the table 2 and ? actuated in rotation on its own axis M by a special drive not shown.

Each mandrel 6 has an internal suction to hold the cylindrical support 2a, 2b coaxially to the mandrel 6.

The printing stations 7a, 7b are positioned at an angular spacing pitch defined around the vertical rotation axis L of the table 5, in particular equal to or multiple of the angular spacing pitch of the mandrels 6.

Table 5? actuated in rotation by steps by a suitable motor drive not shown for the sequential transfer and stationing of the mandrels 6 with the cylindrical supports 2a, 2b below the printing stations 7a, 7b.

The table 5 at each advancement step sequentially positions the cylindrical supports 2a, 2b below the successive printing stations 7a, 7b.

At each step the board 5 stops for the time necessary to print the cylindrical supports 2a, 2b.

With the table 5 stopped, the mandrels 6 are rotated on their own axis M for printing the external lateral surface of the cylindrical supports 2a, 2b.

During the rotation of the mandrels 6 in each printing station 7a, 7b, an ink is dispensed with a single stroke.

Each printing station 7 a, 7 b ? dedicated to the application of a single ink of a color different from that used in the other printing stations 7 a, 7 b. At each print module 3 a, 3 b ? a manipulator 9 is provided for picking up the cylindrical supports 2 a, 2 b to be printed from the conveyor 4 and a manipulator 10 for redelivery of the printed cylindrical supports 2 a, 2 b to the conveyor 4.

To the picking manipulator 9 ? combined a shuttle 22 movable coaxially to the mandrel 6 to receive the cylindrical support 2a, 2b from the withdrawal manipulator 9 and transfer it to the mandrel 6.

A spindle 6 aligns itself with the shuttle 22 at each rotation step of the table 5.

Similarly to the redelivery manipulator 10 ? combined a shuttle 23 movable coaxially with respect to the mandrel 6 to receive the cylindrical support 2a, 2b from the mandrel 6 and transfer it to the redelivery manipulator 10.

Also in this case a spindle 6 aligns itself with the shuttle 23 at each rotation step of the table 5.

The conveyor 4 comprises at regular intervals P a succession of cradles 11a, 11b for housing the cylindrical supports 2a, 2b.

Each cot 11a, 11b ? formed by a single block which defines a cavity 12 for housing the cylindrical support 2a, 2b and the brackets 13 for connection to the conveyor 4.

The stirrups 13 have means for quick coupling to the conveyor 4.

The quick coupling means comprise elastically yielding forks 14. The forks 14 are configured for a shape and force connection with pins 15 supported by the conveyor 4.

The pocket 12 has two inclined longitudinal side walls 16 converging towards a bottom 17 of the pocket 12.

The two inclined side walls 16 delimit an open front base 18 of the socket 12, an open rear base 19 of the socket 12 and a top? open 20 of socket 12.

The two inclined side walls 16 also have an upper edge 24 a folded towards the inside of the cavity 12.

In the recess 12 there are support ribs 21 for the cylindrical support 2a, 2b.

In the preferred case in which at least two printing modules 3 a, 3 b are provided, does the electronic controller (not shown) of the printing machine 1 ? programmed for a mode? of work in parallel of the printing modules 3 a, 3 b in which the capacity? overall productivity of the printing machine 1 ? equal to the sum of the capacity? productivity of the individual printing modules 3 a, 3 b. Transporter 4 ? continuous movement and the electronic controller ? configured to synchronize the phase and speed? of rotation in steps of the table 5 of each printing module 3 a, 3 b with the speed? of continuous advancement of the conveyor 4.

When n operative printing modules are provided, with n?2, the cradles of the conveyor 4 are divided into n groups of cradles, and in each of the n groups the cradles are spaced apart by n steps; moreover, for each of the n operative printing modules, the corresponding withdrawal 9 and redelivery 10 manipulators are associated with a corresponding one of the n groups of cradles.

The electronic controller? programmed to keep the capacity unchanged? productivity of the printing modules 3 a, 3 b operating by adjusting the speed? of advancement of the conveyor 4 as the number of operating printing modules 3 a, 3 b varies.

The functioning of the printing machine 1, with reference to the illustrated version with two printing modules 3 a, 3 b (n=2), ? the following.

It is assumed initially that both printing modules 3 a, 3 b are operative. The cradles 11a, 11b of the conveyor 4 are divided into a first group of cradles 11a and a second group of cradles 11b.

The cradles 11a of the first group are spaced apart by two pitches P.

The cradles 11b of the second group are also spaced from each other by two pitches P.

The withdrawal 9 and redelivery 10 manipulators coupled to the first operative printing module 7a are associated with the cradles 11a of the first group.

The withdrawal 9 and redelivery 10 manipulators coupled to the second operative printing module 7b are associated to the cradles 11b of the second group.

When fully operational, the printing machine 1 has a capacity? production X, understood for example as pieces printed per minute, and a speed? feed Y of conveyor 4.

Do the two printing modules 3 a and 3 b each have the same capacity? productive equal to X/2.

The first printing module 3a operates on the supports 2a present in the cradles 11a while the second printing module 3b operates on the supports 2b present in the cradles 11b.

In practice, assuming the direction of advancement of the conveyor 4 from right to left in figure 1, indicated by directional arrows, in correspondence with the first unit? of printing 3a, the withdrawal manipulator 9 picks up from the conveyor 4 the supports 2a present in the cradles 11a of even order and returns them, after printing, again to the cradles 2a of even order.

Later, at the second unit? of print 3 b the picking manipulator 9 picks up from the conveyor 4 the supports 2 b present in the cradles 11 b of the odd order and returns them, after printing, again to the cradles 2 b of the odd order.

In case of stop of one of the two printing modules 3 a, 3 b, the speed? of advancement Y of the conveyor 4 is halved without modifying the productivity? of the printing module 3 a, 3 b which remains operative and which now processes the supports 2 a and 2b present in all the cradles 11 a, 11 b.

The damaged cradles 11 a, 11 b can be removed quickly with a simple manual operation without the need to remove them. of specific tools, simply with a traction force of intensity? enough to release the forks 14 from the pins 15, while the new cradles 11a, 11b can be assembled just as quickly with a pressure force of intensity? sufficient to snap the forks 14 onto the pins 15.

The cradles 11a, 11b, thanks to their configuration, are particularly suitable for supporting a high production rate of the printing machine 1 since they allow limiting the extension of the stroke necessary to extract the printing supports 2a, 2b from the conveyor 4 and depositing them on the shuttles 22 and vice versa extracting the printing supports 2a, 2b from the shuttles 23 and depositing them in the cradles 11a, 11b.

The withdrawal manipulators 9 can in fact slightly lift from the bottom of the cradles 11a, 11b and axially withdraw the print supports 2a, 2b from the open rear base 19 of the cradles 11a, 11b and then deposit them on the shuttles 22, while the redelivery manipulators 10 can slightly lift from the shuttles 23 and axially insert the print supports 2a, 2b from the open rear base 19 of the cradles 11a, 11b and then deposit them on the bottom of the cradles 11a, 11b.

The ribs 21 in the cavities 12 of the cradles 11 a, 11 b guarantee retention of the print supports 2 a, 2 b in the cradles 11 a, 11 b with the smallest possible contact surface so as not to damage the print, while the turned up edges 24 of the side walls 16 of the cradles 11a, 11b act as chutes for accompanying the printing supports 2a, 2b which, downstream of the last printing module, are unloaded by gravity? from the top? open 20 of the cradles 11a, 11b thanks to the overturning of the cradles 11a, 11b in correspondence with the return angle at 180? of the carrier 4.

The digital inkjet press for printing cylindrical media is so? conceived ? susceptible to numerous modifications and variations, all falling within the scope of the inventive concept; moreover, all the details can be replaced by technically equivalent elements.

In practice, the materials used, as well as? the dimensions may be any according to the requirements and to the state of the art.

Claims (12)

1. Digital inkjet printing machine (1) for printing cylindrical supports (2 a, 2 b), characterized in that it comprises at least one printing module (3 a, 3 b), a conveyor (4) for conveying the cylindrical supports (2a, 2b) to the printing module (3a, 3b), wherein the printing module (3a, 3b) comprises a rotatable table (5) circumferentially equipped with a plurality of of mandrels (6) supporting the cylindrical supports (2 a, 2 b) and surmounted by a plurality? of printing stations (7 a, 7 b) arranged along the circular path performed by the spindles (6) when the table (5) rotates, where does the table (5) ? configured to rotate intermittently for the stationing of the cylindrical supports (2 a, 2 b) below the printing stations (7 a, 7 b), where the spindles (6) are configured to rotate on s? same for the printing of the cylindrical supports (2 a, 2 b) stationed below the printing stations (7 a, 7 b), where ? a manipulator (9) is provided for picking up the cylindrical supports (2 a, 2 b) to be printed from the conveyor (4) and a manipulator (10) for returning the cylindrical supports (2 a, 2 b) printed to the conveyor (4), where the conveyor (4) comprises a succession of cradles (11 a, 11 b) at regular intervals (P) for housing the cylindrical supports (2 a, 2 b), where each cradle (11 a, 11 b) ? formed by a single block which defines a cavity (12) for housing the cylindrical support (2a, 2b) and the brackets (13) for connection to the conveyor (4). 2. Inkjet digital printing machine (1) according to the preceding claim, characterized in that said brackets (13) have means for quick connection to the conveyor (4). 3. Digital inkjet printing machine (1) according to the preceding claim, characterized in that said quick coupling means comprise elastically yielding forks (14). 4. Digital inkjet printing machine (1) according to the preceding claim, characterized in that said forks (14) are configured for a shape and force connection with pins (15) supported by the conveyor (4). 5. Inkjet digital printing machine (1) according to any preceding claim, characterized in that said pocket (12) has two inclined longitudinal side walls (16) converging towards a bottom (17) of the pocket (12) , called two walls (16) delimiting an open front base (18) of the socket (12), an open rear base (19) of the socket (12) and a top? open (20) of the alveolus (12). 6. Inkjet digital printing machine (1) according to the preceding claim, characterized in that said two side walls (16) have an upper edge (24) folded towards the inside of the cavity (12). 7. Digital inkjet printing machine (1) according to any claim 5 and 6, characterized in that in the cavity (12) there are support ribs (21) for the cylindrical support (2a, 2b ). 8. Digital inkjet printing machine (1) for printing cylindrical supports according to any preceding claim, characterized in that it comprises an electronic controller, at least two printing modules (3 a, 3 b), where the conveyor (4) ? configured for conveying the cylindrical supports (2 a, 2 b) to the two printing modules (3 a, 3 b), where the electronic controller ? programmed for a mode? of work in parallel of the printing modules (3 a, 3 b) in which the capacity? overall production of the printing machine (1) ? equal to the sum of the capacity? production of the individual printing modules (3 a, 3 b). 9. Digital inkjet printing machine (1) for printing cylindrical supports (2 a, 2 b), characterized in that it comprises an electronic controller, at least two printing modules (3 a, 3 b), a conveyor (4) for conveying the cylindrical supports (2 a, 2 b) to the two printing modules (3 a, 3 b), where each printing module (3 a, 3 b) comprises a rotatable table (5) equipped circumferentially of a plurality? of mandrels (6) supporting the cylindrical supports (2 a, 2 b) and surmounted by a plurality? of printing stations (7 a, 7 b) arranged along the circular path performed by the spindles (6) when the table (5) rotates, where does the table (5) ? configured to rotate intermittently for the stationing of the cylindrical supports (2 a, 2 b) below the printing stations (7 a, 7 b), where the spindles (6) are configured to rotate on s? same for the printing of the cylindrical supports (2 a, 2 b) stationed below the printing stations (7 a, 7 b), where for each printing module (3 a, 3 b) ? a manipulator (9) is provided for picking up the cylindrical supports (2 a, 2 b) to be printed from the conveyor (4), and a manipulator (10) for returning the cylindrical supports (2 a, 2 b) printed to the conveyor (4) , where the conveyor (4) comprises a succession of cradles (11 a, 11 b) at regular intervals (P) for housing the cylindrical supports (2 a, 2 b), where the electronic controller ? programmed for a mode? of work in parallel of the printing modules (3 a, 3 b) in which the capacity? overall production of the printing machine (1) ? equal to the sum of the capacity? production of the individual printing modules (3 a, 3 b). 10. Digital inkjet printing machine (1) according to the preceding claim, characterized in that said conveyor (4) is continuous motion and said electronic controller ? configured to synchronize the phase and speed? of rotation in steps of said table (5) of the printing modules (3 a, 3 b) with the speed? of continuous advancement of said conveyor (4). 11. Digital inkjet printing machine (1) according to any claim 9 and 10, characterized in that when n operating printing modules are provided, the cradles of the conveyor (4) are divided into n groups of cradles, in each of the n groups of cradles are spaced by n steps, and for each of the n operative printing modules the corresponding pick-up and redelivery manipulators (9, 10) are associated with a corresponding one of the n groups of cradles. 12. Ink-jet digital printing machine (1) according to any claim from 9 to 11, characterized in that the electronic controller ? programmed to keep the capacity unchanged? productivity of the operational printing modules by adjusting the speed? advancement of the conveyor (4) as the number of operating printing modules varies.