HK1252381B - Apparatus for controlled motion of printing units and package making machine incorporating such apparatus - Google Patents

Description

Device for the controlled movement of a printing unit and machine comprising such a device

Technical Field

The present invention generally applies to the field of printing devices and, in particular, relates to a device for the controlled movement of a printing unit designed to print text or images on a sheet surface, the device being suitable for connection to a machine for cutting and creasing customized packaging.

The invention also relates to a machine for cutting, creasing and printing customized packaging from sheet material, said machine comprising said device for driving a printing unit.

Background Art

As is well known in the art, a printing unit has one or more inkjet heads for printing an image or text on one side of a relatively rigid sheet material such as corrugated cardboard.

The printing unit of the present invention is suitable for being mounted preferably, but not exclusively, on a printing device connected to a custom packaging manufacturing machine and for so-called large format printing.

Said known device comprises means for driving the printing unit, which are adapted to promote a selective movement of the printing unit in a direction perpendicular to the direction of transport of the sheet material, thereby controlling the position of the printing head relative to the surface of the sheet material to be printed.

JPS6299178 discloses a print head drive device comprising a belt or wire wrapped around a motorized pulley and secured at one end to a print head carriage, wherein the belt is tensioned by a pair of idle rollers rigidly connected to the carriage and resiliently biased by a spring.

US Pat. No. 5,779,376 and US Pat. No. 6,305,780 disclose corresponding print head carriage drive devices having a belt comprising ends fixed to the frame or the carriage, respectively, and a middle portion interacting with a motorized pulley. The belt is held taut by a spring fixed to the frame or by a plurality of appropriately preloaded return pulleys.

While the above-described prior art systems can eliminate print head fluctuation, they are specifically designed to drive lightweight, small-sized print heads employed in small devices such as printers or scanners.

Therefore, the above device cannot be used for an apparatus for printing large-format sheets having a heavy, large-sized printing head and a support.

In order to avoid the above-mentioned disadvantages, special devices have been developed, the purpose of which is to drive a printing unit for large-format sheets, which devices generally include a fixed frame, at least one box-like support for the printing unit and slidably mounted on a guide device rigidly connected to the frame, and a drive device for driving the box-like support along the guide device.

The frame has one or more extension seats housing a box-like support detachably connected to the printing unit and slidably mounted to guide means extending along the respective seat and allowing the printing unit to move over the surface of the material to be printed.

The drive device comprises a rack-and-pinion mechanism. In addition, to prevent the sheet from adhering to the support, two flexible belts are provided, the ends of which are connected to corresponding idle rollers, which are connected to the frame and the support.

A first disadvantage of said prior art device is that its drive device has many parts, thereby increasing the complexity of its assembly and operation.

Furthermore, the device is very costly and requires frequent maintenance, as the mechanism must be regularly lubricated to prevent the pinion and/or rack from seizing and wearing.

Another disadvantage of this prior art device is that periodic lubrication of the pinion and rack may result in lubricant dripping, which may land on other parts of the device or the surrounding environment.

Furthermore, constant lubrication of the mechanism is not sufficient to prevent wear of the pinion and rack, which are in constant contact with each other and may result in the formation of gaps which reduce the positioning accuracy of the printing unit or, even worse, jam the components.

Another serious drawback of the device described is that it uses wind-up/unwinding rollers connected to the ends of the belt, and the service life of the wind-up/unwinding rollers is limited.

Therefore, any malfunction of the roller during operation of the device may affect the tensioning of the belt, thereby causing damage to the sheet or the printing head.

In view of the prior art, the technical problem solved by the present invention is to provide a device for the controlled movement of an inkjet print head, wherein the inkjet print head is used to print images on one or more sides of a sheet. The device is very simple and reliable, requires almost no maintenance, facilitates the transportation of the sheet, and ensures that the print head moves quickly and accurately in the driving direction.

Summary of the Invention

The object of the present invention is to solve the above technical problems and avoid the above disadvantages by providing a device for the controlled movement of a printing unit designed to print graphics on one or more sides of a sheet, said device being highly efficient and relatively cost-effective.

A particular object of the invention is to provide a device for the controlled movement of a printing unit as described above which has a relatively simple structure and a small number of components.

Another object of the present invention is to provide a device for the controlled movement of a printing unit designed to print graphics on one or more sides of a sheet, which device allows the printing unit to be displaced with high precision in its displacement direction.

Another object of the present invention is to provide a device for the controlled movement of a printing unit designed to print graphics on one or more sides of a sheet, said device being highly reliable and having a long life.

Another object of the present invention is to provide a device for the controlled movement of a printing unit designed to print graphics on one or more sides of a sheet, said device being highly reliable and having a long life.

As better explained below, the above and other objects are achieved by a device for controlled movement of a printing unit designed to be mounted on the customized packaging manufacturing machine of the present invention.

In particular, the device includes at least one support for one or more printing units and a device for driving the support, the driving device includes at least one fixed flexible belt segment with a predetermined length, the ends of the belt segment are stably fixed to the frame, and at least one powered roller connected to the support, and the middle part of the belt segment is at least partially wrapped around the powered roller for rotation of the powered roller to drive the movement of the support relative to the belt segment.

Through the above solution, the structure of the device is simplified, with fewer details and high reliability, and the movement of the printing unit can be controlled more easily and accurately.

In another aspect, the present invention relates to a custom packaging manufacturing machine comprising the above-described drive device.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent from the detailed description of a preferred, non-exclusive embodiment of an apparatus for controlled movement of a printing unit and a customized packaging manufacturing machine, the printing unit being designed to be mounted on the customized packaging manufacturing machine, said apparatus and customized packaging manufacturing machine being described as non-limiting examples with the aid of the accompanying drawings, in which:

FIG1 is a perspective view of a custom packaging manufacturing machine including a printing device having a controlled motion device for driving a printing unit installed therein according to the present invention;

FIG2 is a perspective view of the printing device of FIG1;

FIG3 is a front cross-sectional view of the device of FIG2 ;

FIG4 is a side sectional view of a first detail of FIG3 ;

FIG5 is an enlarged view of a portion of FIG4;

FIG6 is a cross-sectional perspective view of a detail of FIG4;

FIG7 is a perspective view of a third detail of FIG2 ;

FIG8 is an enlarged view of a portion of FIG7 ;

FIG9 is a cross-sectional perspective view of further detail of FIG3;

Figures 10 and 11 are enlarged views of details of Figure 9;

FIG12 is an exploded perspective view of a detail of FIG4;

FIG. 13 is a perspective view of an embodiment of a printing apparatus having a device for driving a printing unit according to the present invention installed therein.

DETAILED DESCRIPTION

1 generally shows and describes a device for the controlled movement of a printing unit 2 designed to print a graphic I on one or more sides F of a sheet M moving along a longitudinal feed direction L.

In particular, as shown in FIG. 1 , the device 1 can be operated in a stand-alone mode or can be connected to a machine 3 for manufacturing packaging from rigid or semi-rigid sheet material M, such as corrugated cardboard.

As is known in the art, the machine 3 has a substantially horizontal feed plane 4 for feeding sheets M, a device 5 for feeding the sheets M longitudinally on the plane 4, and a cutting and creasing device 6 for forming cuts and/or fold lines in the sheets M to form packages of predetermined user-selectable sizes.

The machine 3 also includes at least one printing unit 2, which is located upstream or downstream of the cutting and folding device 6 and has one or more inkjet printing heads 7 that are essentially coplanar with the feed plane 4, for printing text and/or graphics I on one side F of the sheet M being cut and folded.

Each printing unit 2 may comprise a box-like housing 8 having a top wall 9 on which at least one inkjet print head 7 is fixed, the box-like housing 8 interacting with one face F of the material M to be printed.

For example, in the illustrated configuration, each printing unit 2 houses a pair of inkjet print heads 7 that are longitudinally spaced apart at a predetermined interval and at least partially laterally overlapped.

The printing unit 2 is adapted to be movable in a corresponding transverse direction so as to print the graphic I at any position of the sheet M.

The drive device 1 of the invention moves the printing unit 2 and comprises a preferably box-shaped fixed frame 10 with a transverse axis T of extension.

The frame 10 may have a top surface 11 defining a sliding plane π for the sheet M, the sliding plane π being substantially coplanar with the feed plane 4 of the machine 3 .

9 to 11 , at least one box-shaped support 12 is slidably mounted on transverse guides 13 integral with the frame 10. Furthermore, the support 12 has a cavity 14 for detachably housing the housing 8 of the printing unit 2.

Each support 12 is housed in a transverse support 15 provided in the frame and having a transverse guide 13 mounted therein.

The top of the seat 15 is open to allow the support 12 to slide transversely therein and has a depth p ₁ to enable the top wall 9 of each printing unit 2 to be substantially coplanar with the sliding plane π.

In this way, the print head 7 is held at a position facing the slide plane π to print the bottom surface F of the sheet M by ejecting ink upward.

As shown in FIG. 9 , a quick connection device 16 may further be provided for snap-connecting the housing 8 to the support 12 .

The support 12 may be constituted by two longitudinal side walls 17 , 18 and two transverse side walls 19 , 20 , oriented substantially vertically and connected together and to a substantially horizontal bottom wall 21 .

Furthermore, the guide device 13 may comprise at least one transverse guide 22 , 23 which is stably fixed to the frame 10 and/or one or more slides 24 , 25 which are slidably mounted to the respective guide 22 , 23 and rigidly connected to the support 12 .

As best shown in FIGS. 9 , 10 and 11 , the guide means 13 may comprise a transverse guide 11 situated below the bottom wall 21 of the box-like support 12 and an additional transverse guide 23 facing the transverse wall 19 of the support 12 .

At least one slider 24 , 25 slides on the guide members 22 , 23 and is fixed to the bottom wall 21 and the transverse wall 19 of the support member 12 , respectively.

Conveniently, the device 1 comprises drive means 26 for pushing the box-like support 12 along the transverse guide means 13 .

In particular, to enable the print head 7 to print the material M in its width direction, the drive device 26 can push the support 12 to move between two lateral end positions, the distance between the two lateral end positions being equal to or greater than the maximum dimension of the sheet M.

According to a unique aspect of the present invention, as best shown in Figures 3 to 9, the drive device 26 includes at least one fixed flexible belt segment 27 having a predetermined length l, the ends 28, 29 of the belt segment being designed to be stably fixed to the frame 10.

In addition, the belt 27 has a corresponding middle portion 30 at each box-shaped support 12, which is at least partially wrapped around at least one powered roller 31 connected to the box-shaped support 12 and is suitable for pushing the support 12 to move relative to the belt segment 27 through its rotation.

As best shown in FIGS. 4 , 5 and 9 , the ends 28 , 29 of the belt 27 are securely secured to corresponding end regions 32 , 33 of the frame 10 .

Preferably, as best shown in FIGS. 7 and 8 , the belt 27 may have a toothed inner surface 34 and may be equipped with tensioning devices 35 connected to the end regions 32 , 33 of the frame 10 .

In particular, each end 28, 29 of the belt 27 can be wound around a respective cylindrical toothed brake 36, 37 rigidly connected to a bracket 38, 39 pivoting relative to a fixed support 40, 41 provided with a semicircular groove 42, 43.

The movement of the brackets 38, 39 causes the brakes 36, 37 to rotate, thereby tensioning the belt 27. In addition, the belt 27 can be kept taut under tension by locking the brackets 38, 39 to the supports 40, 41, i.e. by tightening the bolts 44, 45 into the grooves 42, 43.

Conveniently, as shown in FIG. 12 , the device 1 may comprise a pair of upper return rollers 46 , 47 outside the longitudinal walls 17 , 18 of the support 12 and a pair of lower return rollers 48 , 49 outside the bottom wall 21 of the support 12 .

The pair of upper return rollers 46 , 47 and the pair of lower return rollers 48 , 49 are idly mounted on respective longitudinal rotation axes L ₁ , L ₂ , L ₃ , L ₄ and have respective outer surfaces 50 , 51 , 52 , 53 designed to interact with the belt 27 .

As best shown in FIGS. 3 to 5 , the pair of upper rollers 46 , 47 may be mounted outside the longitudinal walls 17 , 18 of the support 12 such that the intermediate portion 30 of the belt 27 completely encompasses the pair of upper rollers and the bottom wall 41 .

Furthermore, the power roller 31 may be interposed between the pair of lower return rollers 48 , 49 .

The return rollers 46, 47, 48, 49 impose a general omega shape (ω) on the middle portion 30, with the belt 27 wrapped around the lower rollers 48, 49 from the bottom and around the powered roller 31 from the top.

7 , the total length ( _lt ) of belt segment 27 is substantially equal to the sum of the distance _d1 between end regions 32, 33 of frame 10 and the length d2 of each generally Ω-shaped intermediate portion ₃₀ ( _lt = _d1 + _2d2 ).

The powered rollers 31 are rotatable about respective longitudinal rotation axes R and have outer peripheral surfaces 45 with a high coefficient of friction to grip the inner surface 34 of the belt 27 .

Preferably, the belt 27 is provided with a toothed inner surface 34 and the power roller 31 is also provided with a toothed outer surface 54 with corresponding spacing.

Conveniently, the height _hi of the pair of upper rollers 46, 47 from the ground is substantially equal to the height _h2 of the brakes 36, 37 from the ground.

Thus, as shown in FIG. 7 , the belt 27 has two or more substantially straight portions 55 , 56 , 57 parallel to the ground, said portions being designed to close the top of the seat 15 of the frame 10 in which the support 12 is slidably mounted.

The outer surface 58 of the belt 27 is therefore substantially coplanar with the sliding plane π, thus preventing the sheet M from encountering gaps or voids in its feed direction L and from adhering to the support 15 .

Preferably, as best shown in FIGS. 8 and 9 , the roller 31 may be mounted on the rotation shaft 59 of a motor 60 fixed directly to the transverse wall 19 of the support 12 .

The device 1 may further comprise electronic control means, not shown, operatively connected to the electric motor 62 to control its movements and promote a precise displacement of the support 12 along the transverse guide 13 .

In a preferred configuration of the invention, as shown in the figures, the device 1 may comprise a plurality of supports 12 housed in a single seat 15 , each support being able to slide on a common guide 13 .

In particular, a single common belt segment 27 may be provided, which is adapted to be wound circumferentially around all the box-like supports 12 located within the seat 15 so as to define a respective intermediate portion 30 for each box-like support 12 .

Each powered roller 31 is mounted to a corresponding support 12 to allow independent longitudinal movement of each printing unit 2 .

In another configuration of the present invention, as shown in FIG. 13 , the frame 10 may include a plurality of longitudinally offset supports 15 having one or more box-like supports 12 and a single belt segment 27 slidably mounted within the longitudinally offset supports.

Thus, the powered rollers 31 associated with the supports 12 located in different seats 15 are adapted to interact with different belt segments 27 .

In another aspect, the invention provides a customized packaging manufacturing machine 3 having at least one printing unit 2 connected to a drive device 1 as described above.

Within the inventive concept disclosed in the appended claims, the device and machine of the present invention can be subjected to various changes or modifications. Without departing from the scope of the present invention, all its details can be replaced by other technically equivalent parts, and the materials can be changed according to different needs.

Although the device and the machine have been described with particular reference to the accompanying drawings, the numerals employed in the present invention and claims are only used for a better understanding of the present invention and are not intended to limit the scope of protection claimed in any way.

The invention is applicable in industry, since it can be manufactured on an industrial scale in plants producing machines designed for processing semi-rigid sheet products such as cardboard etc., or in plants producing packaging forming machines.

Claims (13)

1. A device (1) for controlled movement of a printing unit (2) for printing an image (I) on one or more sides (F) of a sheet (M) designed to move in a feed direction defining a longitudinal axis (L), the device (1) being adapted to be connected to a machine (3) for cutting and folding custom packaging, and comprising: —A fixed frame (10) for defining an extending transverse axis (T) and having transversely spaced end regions (32, 33), the frame (10) having a top surface (11) for defining a sliding plane (π) for the sheet (M); —At least one box-shaped support (12) for a corresponding printing unit (2) and slidably mounted on a transverse guide (13) integral with the frame (10), the support (12) being housed in a transverse support (15) provided in the frame (10), and the transverse support (15) having a transverse guide (13) mounted therein. —A drive device (26) for controlled movement of at least one box-shaped support (12) along the transverse guide device (13), the drive device (26) comprising at least one flexible belt and at least one power roller (31) connected to the support (12); The feature is that the flexible belt is an open belt segment (27), the belt segment (27) having a predetermined length (l) and including end portions (28, 29) stably fixed to the end regions (32, 33) of the frame (10) and corresponding intermediate portions (30), the intermediate portions being partially wound around the power roller (31) for rotation of the power roller to drive the movement of the support (12) relative to the belt segment (27), the belt segment (27) having an outer surface (58) and two or more generally straight portions (55, 56, 57) parallel to the ground, the generally straight portions being designed to close the top of the support (15) of the frame (10), the support (12) being slidably mounted within the frame (10) such that the outer surface (58) is substantially coplanar with the sliding plane (π) to prevent the sheet (M) from encountering gaps or voids in its feeding direction and to prevent the sheet (M) from adhering to the support (15). 2. The apparatus for controlled movement of a printing unit (2) as claimed in claim 1, characterized in that it includes a tensioning device (35) for tensioning the belt segment (27) and connected to the end regions (32, 33) of the frame (10). 3. The apparatus for controlled movement of a printing unit (2) as claimed in claim 1, characterized in that the at least one support (12) comprises a pair of upper return rollers (46, 47) and a pair of lower return rollers (48, 49), the pair of upper return rollers (46, 47) and the pair of lower return rollers (48, 49) being spaced apart from each other in the horizontal and vertical directions for tensioning the belt segment (27) and applying at least one generally Ω-shaped path to the intermediate portion (30), and moving parallel to the transverse guide device (13). 4. The apparatus for controlled movement of the printing unit (2) as claimed in claim 3, characterized in that the total length (l _t ) of the belt segment (27) is substantially equal to the sum of the distance (d ₁ ) between the end regions (32, 33) of the frame (10) and the extension length (d ₂ ) of each generally Ω-shaped middle portion (30). 5. The apparatus for controlled movement of the printing unit (2) as claimed in claim 4, characterized in that the pair of upper return rollers (46, 47) and the pair of lower return rollers (48, 49) are idling mounted on corresponding longitudinal axes ( _L1 , _L2 , _L3 , _L4 ) and have outer cylindrical surfaces (50, 51, 52, 53) adapted to interact with the opposing surfaces (34, 58) of the belt segment (27). 6. The apparatus for controlled movement of a printing unit (2) as claimed in claim 3, characterized in that the at least one power roller (31) is inserted between the pair of lower return rollers (48, 49) and has a generally longitudinal axis of rotation (R), such that the belt segment (27) winds around the lower return rollers (48, 49) from the bottom and around the power roller (31) from the top. 7. The apparatus for controlled movement of a printing unit (2) as claimed in claim 1, characterized in that the at least one power roller (31) has an outer surface (54) with a high coefficient of friction to clamp the belt segment (27) and is driven by an electric motor (60), the power roller (31) being rigidly connected to the at least one box-shaped support (12). 8. The apparatus for controlled motion of a printing unit (2) as claimed in claim 7, characterized in that the belt segment (27) and the power roller (31) are respectively provided with toothed surfaces on their inner surface (34) and outer surface (54), and the surfaces are in contact with each other. 9. The apparatus for controlled movement of a printing unit (2) as claimed in claim 1, characterized in that the guiding device (13) comprises one or more transverse guides (22, 23), the transverse guides being fixed to the frame (10) and adapted to slidably support one or more sliders (24, 25), the sliders being rigidly connected to the at least one support (12). 10. The apparatus for controlled movement of a printing unit (2) as claimed in claim 1, characterized in that the apparatus comprises two or more parallel box-shaped supports (12), each box-shaped support having a corresponding power roller (31) that interacts with a single common belt segment (27). 11. The apparatus for controlled motion of a printing unit (2) as claimed in claim 1, characterized in that the apparatus comprises two or more longitudinally offset box-shaped supports (12), the box-shaped supports being connected to corresponding power rollers (31) to interact with corresponding independent belt segments (27). 12. A machine (3) for cutting and folding sheets (M) for customized packaging, comprising: —A feed plane (4) is provided along the longitudinal axis (L) and is used for the sheet (M); —A cutting and folding device (6) for forming cuts and/or folds on a sheet (M) placed on the feed plane (4); —At least one printing unit (2), the printing unit being located upstream or downstream of the cutting and folding device (6) and having at least one inkjet printhead (7), the inkjet printhead being used to print a custom graphic (I) on one side (F) of the sheet (M); The machine is characterized in that it includes a device (1) for controlled movement of the printing unit (2) as described in any one of claims 1-11. 13. The machine as claimed in claim 12, wherein the at least one printing unit (2) has a plurality of inkjet heads (7) that are longitudinally offset along a predetermined interval and at least partially stacked laterally.