阅读说明：本技术 用于接纳中空圆柱形物体的安装装置以及印刷系统 (Mounting device for receiving a hollow cylindrical object and printing system ) 是由 延斯·皮特·耶格尔 卡尔·赫尔穆特·泰特 于 2019-03-18 设计创作，主要内容包括：一种用于在印刷系统中保持中空圆柱形物体(6)、特别是螺旋盖的安装装置(1),包括：支撑构件(7)；用于接纳中空圆柱形物体(6)的芯轴(2),所述芯轴(2)布置在支撑构件(7)处；以及加热装置(5),所述加热装置用于加热安装在芯轴(2)处的所述中空圆柱形物体(6)。一种用于在中空圆柱形物体(6)、优选为螺旋盖上印刷的印刷系统,包括至少一个安装装置,以及至少一个印刷头,该印刷头构造成在圆柱形物体、优选为螺旋盖的表面上印刷。(Mounting device (1) for holding a hollow cylindrical object (6), in particular a screw cap, in a printing system, comprising: a support member (7); a mandrel (2) for receiving a hollow cylindrical object (6), the mandrel (2) being arranged at a support member (7); and a heating device (5) for heating the hollow cylindrical object (6) mounted at the mandrel (2). A printing system for printing on a hollow cylindrical object (6), preferably a screw cap, comprises at least one mounting device, and at least one print head configured to print on a surface of the cylindrical object, preferably the screw cap.)

1. Mounting device for holding a hollow cylindrical object, in particular a screw cap, in a printing system, comprising:

a support member, and

a mandrel for receiving a hollow cylindrical object, the mandrel being arranged at the support member, characterized in that

A heating device for heating the hollow cylindrical object mounted at the mandrel.

2. The mounting device according to claim 1, wherein the heating device is configured to heat the hollow cylindrical object from an outside of the hollow cylindrical object and/or the heating device is configured to heat the hollow cylindrical object from an inside of the hollow cylindrical object.

3. A mounting device according to any preceding claim, wherein the heating device comprises an internal heating unit.

4. A mounting device according to claim 3, wherein the internal heating unit comprises a heat source, preferably a heating wire, more preferably a plurality of heating wires.

5. A mounting device according to claim 3 or 4, wherein the heating unit is arranged to heat the outer surface of the mandrel and/or the heating unit is arranged to heat a fluid, preferably air, directed to the mandrel.

6. The mounting device according to any one of the preceding claims, wherein the heating device comprises a wireless induction unit for wireless induction heating of the hollow cylindrical object and/or the heating device comprises an infrared heating unit for emitting infrared radiation.

7. A mounting device according to any preceding claim, wherein the heating device comprises a fluid supply conduit for supplying a flow of heating fluid to the mandrel.

8. The mounting device of claim 7, wherein the mandrel comprises a heated fluid channel for directing the fluid flow towards an inner surface of the hollow cylindrical object.

9. The mounting device according to claim 8, wherein the mandrel comprises a mounting sleeve comprising the form of a hollow cylinder, wherein preferably the heated fluid channel is arranged within the mounting sleeve, wherein preferably the mounting sleeve comprises one or more openings in fluid communication with the heated fluid channel.

10. A mounting device according to claim 9, wherein one or more spacers are arranged on the outer surface of the mounting sleeve for providing a gap between the outer surface of the mounting sleeve and the inner surface of the hollow cylindrical object, wherein preferably the one or more spacers are arranged on the outer side surface of the mounting sleeve and/or the outer end face of the mounting sleeve.

11. The mounting device of claim 9 or 10, wherein the mounting sleeve extends along a longitudinal axis and comprises an expansion region, wherein the mandrel further comprises a core arranged inside the mounting sleeve, wherein the core is movable relative to the mounting sleeve,

wherein the core is configured to be positioned relative to the mounting sleeve at a first location of the core where the expanded region is in an unexpanded state, and at a second location of the core relative to the mounting sleeve where the core exerts a radial force on the expanded region such that the expanded region is radially expanded relative to the expanded region in the unexpanded state.

12. The mounting device of claim 11,

in the unexpanded state, the mounting sleeve comprises a maximum outer diameter equal to or slightly smaller than an inner diameter of the cylindrical object to be received by the mandrel, and

in the expanded state, the mounting sleeve comprises a maximum outer diameter that is larger than an inner diameter of the cylindrical object to be received by the mandrel.

13. A mounting device according to any one of claims 9 to 13, wherein the mounting sleeve comprises a plurality of grooves extending substantially along the longitudinal axis, the plurality of grooves being arranged circumferentially relative to the longitudinal axis to form the expansion region, wherein preferably the plurality of grooves are in fluid communication with the heating fluid channel.

14. The mounting device of claim 13, wherein the plurality of slots are arranged such that in the expansion region, the mounting sleeve includes a plurality of ribs extending along the longitudinal axis.

15. A mounting device according to claim 14, wherein one or more ribs comprise spacers, wherein preferably each rib comprises a spacer.

16. A mounting device according to any one of the preceding claims, wherein the heating device comprises a flow generating unit, preferably a pump or a fan, for providing a fluid flow, preferably an air flow, in the heating device.

17. A mounting device according to any preceding claim, wherein the heating device comprises a fluid return conduit for redirecting fluid from the mandrel to the heating unit.

18. A mounting device according to any one of the preceding claims, wherein the mandrel is rotatably supported on the support member, wherein preferably the heating device comprises a heating region arranged adjacent the mandrel for heating an outer side surface of the hollow cylindrical object.

19. A mounting device according to any one of the preceding claims, wherein a plurality of mandrels are arranged circumferentially on the support member about a central axis, wherein preferably the support member is rotatable about the central axis.

20. A mounting device according to any preceding claim, further comprising tilting means for tilting the support member relative to a reference plane.

21. The mounting device of any one of the preceding claims, wherein the heating device comprises a connection unit for connecting to an external heat source.

22. The mounting device according to any one of the preceding claims, further comprising a battery and/or a contact unit, preferably comprising a sliding contact, preferably a brush, for electrical connection with a power source.

23. A printing system for printing on hollow cylindrical objects, preferably screw caps, comprising

At least one mounting device according to any one of the preceding claims, and

at least one print head configured to print on a surface of a cylindrical object, preferably a screw cap.

Technical Field

The invention relates to a mounting device for receiving a hollow cylindrical object, in particular a screw cap (screw cap), in a printing system. Furthermore, the invention relates to a printing system for printing on hollow cylindrical objects, preferably on screw caps.

Background

As with other manufacturing industries, the brand of product is an important strategic and marketing element for bottled beverage producers. When a unique brand is developed for bottled beverages where the container design is substantially uniform, such as screw-top bottles, the design of the label and screw-top is essentially the only designable element. For this reason, a printing system capable of printing on labels and screw caps is required. The screw cap geometry presents a particular challenge for corresponding printing devices, since screw caps are cylindrical objects with a planar top surface and a cylindrical side surface, both surfaces being printed. Such a printing process requires a far more advanced technology than printing on flat labels, to which conventional paper printing technology can be applied.

WO 2015/16628 a1 discloses an exemplary apparatus for printing on cylindrical objects. It comprises a plurality of fixed print heads and holding means for holding the cylindrical object in a fixed orientation. The holding device moves the cylindrical object into the vicinity of the print head so that the print head can print on the cylindrical object. The fixed orientation of the cylindrical object ensures a reproducible orientation of the print head relative to the cylindrical object, so that the ink delivery system required to feed the ejectors of the print head can be simplified.

In order to hold the caps during printing, it is known to use mandrels (mandrel) which have received the caps from respective supplies before printing. In order to print the cap, it must be held in a fixed position and orientation on the mandrel, since the cap is then printed in several colors. Each printing step for each colour must coincide with the preceding and the following printing step in position and orientation so that the complete figure to be printed on the lid is correctly applied to the lid.

Therefore, the cover must be held firmly on the mandrel, thus requiring a relatively large force. In this respect, it is known to hold a cap received on a mandrel in a fixed position on the mandrel via suction by providing a vacuum to the suction means of the mandrel, as disclosed for example in US 6,769,357B1 and US 6,167,805 Bl.

It is known to arrange a plurality of mandrels on a mounting device that is a component of a printing system, enabling a plurality of screw caps to be mounted on these mandrels of the mounting device, so that a plurality of screw caps can be processed by moving the mounting device relative to a print head of the printing system.

Screw caps usually have a small wall thickness. Therefore, they have the property of flexibility. That is, when a vacuum is used to hold the cap in a fixed position on the mandrel, the inner cylindrical surface of the cylindrical portion of the cap and the outer cylindrical surface of the mandrel must establish a high precision fit. Otherwise, the relatively flexible cylindrical wall of the lid is easily deformed by the suction force, which would result in distortion of the graphics printed on the deformed cylindrical outer surface or the deformed planar top surface.

Furthermore, it is necessary to provide each mandrel of the printing apparatus with a vacuum line that can be controlled independently. Therefore, securing the lid on the mandrel by suction requires complex piping, the provision of a vacuum system, and the provision of a mandrel comprising a high precision contact surface for receiving the lid. Furthermore, the continuous supply of vacuum to the apparatus results in high energy costs. That is, known printing devices are expensive to produce and operate.

In digital printing, very small ink droplets are ejected from the nozzles of a printhead and are deposited on a substrate to form an image. Depending on the surface energy of the substrate to be printed and the surface tension of the liquid ink deposited on the substrate, the ink droplets tend to spread rapidly and eventually merge in the case where the surface energy of the substrate is higher than the surface tension of the ink, or to shrink in a very short time in the case where the surface energy of the substrate is lower than the surface tension of the liquid ink.

The time available between droplet deposition and the onset of diffusion and fusion or shrinkage is referred to as the curing delay. Curing (pining) converts the low viscosity ink into a high viscosity gel that is essentially immobile and cannot spread or shrink any more, but is still flexible and allows for the deposition and stable adhesion of subsequently printed inks or varnishes. Therefore, the curing or drying of the ink should start before the spreading or shrinking of the ink droplets, respectively. Therefore, in order to prevent uncontrolled spreading or shrinkage of the ink droplets, it is necessary to cure the ink droplets directly after they contact the substrate.

In a common printing system for printing screw caps, UV curable inks are used. To cure the ink, a short pulse of low intensity UV light is directed onto the ink immediately after the ink is deposited.

Although aqueous inks have several advantages over UV-curable inks, aqueous inks have not been used for printing on three-dimensional objects. The curing of the aqueous ink is carried out thermally by slightly preheating the substrate. However, the substrate to be printed must be uniformly heated such that each position of the substrate comprises substantially the same temperature, as substantially the same temperature is required to obtain uniform and high quality printing results. The temperature difference on the substrate surface results in a difference in spreading of the ink droplets. The difference in ink spread in turn leads to a difference in image quality.

Disclosure of Invention

It is an object of the present invention to provide an improved mounting device for receiving a hollow cylindrical object, preferably a screw cap, in a printing system.

The above object is achieved by a mounting device for holding a cylindrical object, in particular a screw cap, in a printing system according to claim 1 and a printing system according to claim 23. Preferred embodiments are set forth in the description, the drawings and the dependent claims.

In particular, the invention proposes a mounting device for holding a cylindrical object, in particular a screw cap, in a printing system, the mounting device comprising a support member and a mandrel arranged at the support member for receiving the hollow cylindrical object. The mounting device further comprises heating means for heating the hollow cylindrical object mounted at the mandrel.

Since the mounting device comprises a heating device for heating the hollow cylindrical object mounted at the mandrel, it is possible to preheat the hollow cylindrical object mounted on the mandrel to a predetermined temperature range before printing and to maintain the temperature of the hollow cylindrical object within the predetermined temperature range during printing. Thus, it is possible to print hollow cylindrical objects with aqueous inks and achieve uniform and high quality printing results.

According to a preferred embodiment, the heating device is configured to heat the hollow cylindrical object from the outside of the hollow cylindrical object. The mounting means and the heating means may thus comprise a particularly simple structure.

Alternatively or additionally, the heating device is configured to heat the hollow cylindrical object from an inside of the hollow cylindrical object. Heating the hollow cylindrical object from the inside may be more efficient than heating the hollow cylindrical object from the outside of the object, since then the heat dissipation towards the hollow cylindrical object may be more efficient and the external influence may be reduced.

In this respect, the terms "inside" and "outside" of the hollow cylindrical object are understood in relation to the radial position with respect to the cylindrical side wall of the hollow cylindrical object. In other words, the "inner side" is the side surrounded by the side wall of the hollow cylindrical object, while the "outer side" corresponds to the side beyond the side wall of the hollow cylindrical object, i.e. the side of the hollow cylindrical object to be printed.

In order to provide heat for heating the hollow cylindrical object, the heating device may preferably comprise an internal heating unit.

According to a preferred embodiment, the internal heating unit comprises a heat source, preferably a heating wire, more preferably a plurality of heating wires.

In order to provide an efficient heating of the hollow cylindrical object, the heating unit may preferably be arranged to heat the outer surface of the mandrel. Alternatively or additionally, the heating unit may be arranged to heat a fluid, preferably air, being directed to the mandrel.

According to a preferred embodiment, the heating device comprises a wireless induction unit for wireless induction heating of the hollow cylindrical object and/or the heating device comprises an infrared heating unit for emitting infrared radiation.

According to another preferred embodiment, the heating means comprises a fluid supply conduit for supplying a flow of heating fluid to the mandrel. Thereby, the heating fluid may serve as a carrier for guiding heat generated offset or spaced apart from the hollow cylindrical object to the hollow cylindrical object.

Preferably, the mandrel comprises a heated fluid channel for directing the fluid flow towards the inner surface of the hollow cylindrical object. Thus, the heating fluid can be heated away from the hollow cylindrical object and guided to the position of the hollow cylindrical object.

In this regard, the mandrel preferably comprises a mounting sleeve comprising the form of a hollow cylinder, wherein preferably the heated fluid passage is arranged within the mounting sleeve, wherein preferably the mounting sleeve comprises one or more openings in fluid communication with the heated fluid passage.

When one or more spacers are arranged on the outer surface of the mounting sleeve to provide a gap between the outer surface of the mounting sleeve and the inner surface of the hollow cylindrical object, the heating fluid may be supplied into the gap. Thus, the heating fluid is able to heat the hollow cylindrical object via thermal convection. Thus, a uniform heat distribution to the hollow cylindrical object can be achieved. Preferably, the heating fluid is supplied into the gap such that a substantially uniform fluid circulation is maintained inside the gap.

Preferably, the one or more spacers are arranged on an outer side surface of the mounting sleeve and/or an outer end face of the mounting sleeve. Thus, the heating fluid may be in contact with a majority of the inside surface of the hollow cylindrical object and/or the inside surface of the top surface of the hollow cylindrical object.

According to another preferred embodiment, the mounting sleeve extends along a longitudinal axis and comprises an expansion region (expansion region), wherein the mandrel further comprises a core (core) arranged inside the mounting sleeve, wherein the core is movable relative to the mounting sleeve, wherein the core is configured to be positionable relative to the mounting sleeve at a first position of the core, in which the expansion region is in an unexpanded state, and the core is configured to be positionable relative to the mounting sleeve at a second position of the core, in which the core exerts a radial force on the expansion region such that the expansion region is radially expanded relative to the expansion region in the unexpanded state.

Thus, thermal expansion of the mandrel and/or thermal expansion of the hollow cylindrical object due to the heating provided by the heating means may be compensated for. Furthermore, a direct mounting of the hollow-cylindrical object to the mounting sleeve can thereby be ensured, and a rigid fixing of the hollow-cylindrical object can also be ensured. Since the expanded region of the mounting sleeve can change its diameter, the outer diameter of the mounting sleeve can be set smaller than the inner diameter of the hollow cylindrical object held by the mandrel in the unexpanded state. Thus, the hollow cylindrical object can be easily placed on the mandrel, at least on the mounting sleeve. Furthermore, there is no need to hold the hollow cylindrical object on the mandrel by suction. Thus, by supplying the heating fluid, it is possible to provide heating of the hollow cylindrical object by supplying the heating fluid while fixing the hollow cylindrical object to the mandrel.

Thus, providing a heating device with a heating unit for heating a fluid and guiding the heated fluid into the mandrel in combination with providing the mandrel with a mounting sleeve comprising an expansion region enables a (pre-) heating of the hollow cylindrical object while ensuring a secure mounting of the hollow cylindrical object on the mandrel. In other words, providing a mounting device with such an expandable mandrel enables the supply of heated fluid from the inside of the mandrel, in particular the inside of the cylindrical mounting sleeve, and thus, in combination, a particularly advantageous preferred solution to the above-mentioned object is achieved.

To secure the hollow cylindrical object to the mandrel, the diameter of the expanded region is widened to a predetermined extent such that a predetermined amount of friction fit may be applied between the outer surface of the expanded region and the inner surface of the hollow cylindrical object received by the mandrel.

Thus, the present invention eliminates the need for a vacuum system and its complex piping arrangement. Furthermore, the tolerance range for the distance between the inner diameter of the hollow cylindrical object and the outer diameter of the mandrel, in particular the outer diameter of the mounting sleeve, is typically smaller compared to mandrels that use vacuum to fix the hollow cylindrical object. Further, with respect to the mandrel and the hollow cylindrical object, a length variation in the radial direction due to heating of both the mandrel and the hollow cylindrical object can be compensated, so that the hollow cylindrical object can be firmly held even when the hollow cylindrical object for printing is heated for printing.

Preferably, the core is movable at least between the first position and the second position, wherein preferably the movement is a displacement in the direction of the longitudinal axis.

Furthermore, the mounting sleeve is preferably made in one piece.

According to a preferred embodiment, the mounting sleeve comprises a sleeve wedge structure on its inner surface. The core preferably comprises a core wedge structure formed complementary to the sleeve wedge structure, wherein, in the first position of the core relative to the mounting sleeve, the sleeve wedge structure and the core wedge structure are configured to be arranged relative to each other such that the expansion region is in an unexpanded state. At a second position of the core relative to the mounting sleeve, the core wedge structure is configured to apply a radial force to the sleeve wedge structure such that the expanded region is radially expanded relative to the expanded region in an unexpanded state. Thus, the degree of expansion of the expansion region may be predetermined by the angle formed by the longitudinal axis and the contact surface of the wedge-shaped structure. Furthermore, due to the wedge-shaped movement, the wedge mechanism, which is related to the input force applied to the core in the direction of the longitudinal axis and the resulting radial force applied by the core to the sleeve, brings a mechanical advantage such that a relatively high radial force can be applied by a relatively small actuation force applied to the core in the direction of the longitudinal axis. Thus, advantageously, the mandrel may exhibit a simple and robust structure. Preferably, the sleeve wedge structure and the core wedge structure are arranged in the expansion region with respect to the longitudinal axis. In other words, the sleeve wedge structure as well as the core wedge structure preferably extend integrally with respect to the longitudinal axis within the limits of the expansion region.

The sleeve wedge preferably comprises at least one contact surface inclined with respect to the longitudinal axis. I.e. the at least one inclined contact surface encloses a predetermined angle with the longitudinal axis. Furthermore, the core wedge structure preferably comprises at least one inclined contact surface formed complementary to the inclined surface of the sleeve wedge structure. Thus, the at least one inclined contact surface also encloses said predetermined angle with the longitudinal axis. In other words, the at least one contact surface of the sleeve wedge structure and the at least one contact surface of the complementarily formed core wedge structure are aligned parallel to each other. Thus, by movement of the core relative to the sleeve, the contact surface of the core is displaced relative to the contact surface of the sleeve, such that when the contact surfaces are in contact with each other, the displacement of the core relative to the sleeve causes the contact surface of the core to slide along the contact surface of the sleeve.

According to a preferred embodiment, the sleeve as well as the core comprise a substantially rotationally symmetrical shape, wherein the core wedge structure comprises a substantially conical form and the sleeve wedge structure comprises a correspondingly shaped inner surface, i.e. a substantially cylindrical form with a cut-out in the conical form. Thereby, radial forces can be applied to the mounting sleeve substantially along the entire circumference of the mounting sleeve, which results in a particularly uniform radial widening of the mounting sleeve.

In a preferred embodiment, the angle enclosed by the contact surface of the sleeve and the longitudinal axis and correspondingly the angle enclosed by the core and the longitudinal axis is less than 45 °. Thus, a force exerted on the core in the direction of the longitudinal axis results in a greater radial force exerted on the sleeve than a force along the longitudinal axis via contact of the contact surfaces of the core wedge structure. When a constant axial force is applied to the mounting sleeve via the core, the smaller the angle, the greater the radial force generated. In other words, at a constant applied axial force, the radial force generated increases as the angle decreases.

Preferably, the angle between the contact surface and the longitudinal axis is between 1 ° and 40 °, preferably 5 ° -30 °, particularly preferably 10 ° -30 °, and very particularly preferably 10 °, 15 °, 20 °, 25 °, or 30 °. Particularly preferably, the angle is in the range of 16 ° to 19 °. Thereby, a self-locking between the core and the sleeve can be avoided and at the same time a high mechanical advantage, in other words a high ratio of radial forces to longitudinal forces, can be provided.

According to a further preferred embodiment, the object is achieved by a sleeve wedge structure comprising a plurality of wedge ring segments arranged adjacent to each other with respect to the longitudinal axis, and in particular by a core sleeve structure comprising a plurality of wedge ring segments arranged adjacent to each other with respect to the longitudinal axis and complementarily formed with respect to the wedge ring segments of the sleeve wedge structure. Thus, the core is typically movable in the direction of the longitudinal axis relative to the mounting sleeve. That is, the radial force exerted by the extended expansion region on the hollow cylindrical object can be evenly distributed along the expansion region with respect to the longitudinal axis. Thus, deformation of the hollow cylindrical object due to fixing the hollow cylindrical object on the mandrel may be significantly reduced, e.g. reduced to a minimum or even completely avoided. Furthermore, each ring segment may comprise a relatively small radial extension inwards towards the longitudinal axis of the mandrel. Furthermore, the displacement of the core in the direction of the longitudinal axis relative to the mounting sleeve may be smaller compared to an embodiment comprising only one continuous wedge extending over the entire length of the expansion region. In other words, the core wedge structure comprises a plurality of truncated cones arranged adjacent to each other with respect to the longitudinal axis. The wedge ring structure thus comprises a plurality of complementarily formed wedge rings extending inwardly from the hollow cylindrical basic form of the sleeve relative to the longitudinal axis.

According to another preferred embodiment, the sleeve wedge comprises an internal thread, wherein the flanks of the internal thread comprise a wedge shape and the core wedge comprises an external thread. Wherein the flanks of the external thread may comprise a wedge shape formed complementary to the flanks of the internal thread. In other words, one of the flanks of the internal thread is inclined at a predetermined angle with respect to the longitudinal axis, thereby forming a helical contact surface of wedge-shaped configuration. Thus, the external thread comprises flanks which are inclined at a predetermined angle with respect to the longitudinal axis and which also form a helical contact surface, so that the inclined contact surface of the external flank can slide on the contact surface of the internal thread. That is, the inclined flanks of the internal thread and the inclined flanks of the external thread interact with each other, so that a helically formed wedge-shaped mechanism is formed.

Preferably, the core is movable relative to the mounting sleeve in the direction of the longitudinal axis, or the core is rotatable relative to the mounting sleeve about the longitudinal axis. The radial extent of the expansion region can thereby advantageously be present uniformly over the entire length of the expansion region. That is, the radial force exerted by the extended expansion region onto the hollow cylindrical object can be evenly distributed with respect to the direction of the longitudinal axis and thus substantially evenly distributed over the entire contact area of the expansion region and the hollow cylindrical object. Thus, the deformation of the hollow cylindrical object due to the fixation to the mandrel may be significantly reduced, e.g. minimized or even completely avoided.

Furthermore, both the mounting sleeve and the side of the core may comprise a relatively small radial extension. Furthermore, the displacement of the core in the direction of the longitudinal axis relative to the mounting sleeve may be smaller compared to an embodiment comprising only one continuous wedge extending over the entire length of the expansion region. Compared to embodiments comprising continuous ring segments, an even distribution of radial forces on the mounting sleeve and further on the hollow cylindrical object can be achieved.

Furthermore, by means of the thread, the sleeve and the core can be easily demoulded during their production. The same applies to the assembly of the mounting sleeve and the core, since the core can easily be screwed into the mounting sleeve without requiring a radially outward displacement of the sleeve.

Preferably, the pitch and lead of the thread are relatively small, respectively, and thus smaller than the pitch and lead of a metric thread, for example corresponding to the diameter of the thread, preferably the lead angle and the helix angle are smaller than 3 °, particularly preferably smaller than 2 °, and very particularly preferably smaller than 1.5 ° or 1 °, respectively.

Furthermore, the angle enclosed between the contact surface of the oblique flank of the internal thread and the longitudinal axis, and thus between the contact surface of the oblique flank of the external thread and the longitudinal axis, is preferably between 1 ° and 40 °, preferably between 5 ° and 30 °, particularly preferably between 10 ° and 30 °, and very particularly preferably between 10 °, 15 °, 20 °, 25 °, or 30 °. Particularly preferably, the angle is in the range of 16 ° to 19 °. Thus, a self-locking between the core and the sleeve can be avoided and at the same time a high mechanical advantage, in other words a high ratio of radial to longitudinal forces, can be provided.

In order to expand the mounting sleeve, according to a first alternative, the core is displaceable in the direction of the longitudinal axis due to the thread, and the core can be fixed against rotation about the longitudinal axis relative to the mounting sleeve. In a second alternative, the core may be fixed against displacement in the direction of the longitudinal axis, while the core may be rotatable about the longitudinal axis relative to the mounting sleeve.

According to another preferred embodiment the mounting sleeve comprises a cover or covering as a separate, preferably movable part. Thereby, the core and optionally also the biasing member may be inserted through the open top of the mounting sleeve and the top closed by a cover or covering.

In order to provide a particularly simple and robust structure, as suggested according to a further preferred embodiment, the spindle may further comprise a biasing member, preferably a spring, for biasing the core in the fixed position, preferably in the first position or the second position, wherein the biasing member is preferably supported against a support element or a support area of the spindle.

According to another preferred embodiment, the mandrel further comprises an actuator member for moving the core between the first and second positions. Thus, the position of the core can be easily predetermined and controlled. Preferably, the actuator member is configured for interacting with a cam, wiper, lobe or guide of a mounting device or printing system.

In order to be able to remove the hollow cylindrical object from the mandrel in a controlled manner, preferably, the mandrel may further comprise: a mechanical ejector for mechanically removing, preferably pushing open, the cylindrical object from the mandrel; and/or further comprising a pneumatic ejector for removing the cylindrical object from the mandrel using compressed air. Preferably, the pneumatic expeller comprises a valve and/or a connection to a pneumatic air supply system.

According to a further preferred embodiment, in the unexpanded state the mounting sleeve comprises a maximum outer diameter equal to or slightly smaller than an inner diameter of the cylindrical object to be received by the mandrel. In the expanded state, a maximum outer diameter of the expanded region is larger than an inner diameter of the cylindrical object to be received by the mandrel. The term "slightly" should be understood that the clearance or gap created by the difference between the inner diameter of the cylindrical object and the outer diameter of the mounting sleeve is smaller than the expansion of the mounting sleeve created by the movement of the core from the first position to the second position. Preferably, the maximum diameter of the mounting sleeve is about 0.01mm to 0.5mm, particularly preferably 0.05mm to 0.1mm smaller than the inner diameter of the hollow cylindrical object in the unexpanded state. Preferably, the maximum outer diameter of the mounting sleeve is set to a value of: which in the unexpanded state establishes a clearance fit by the inner circumferential surface of the hollow cylindrical object with the outer surface of the mounting sleeve.

It is possible to mount the hollow cylindrical object directly on the mandrel and, in addition, to secure and secure the hollow cylindrical object on the mandrel. According to another preferred embodiment, the difference between the diameter of the expanded area in unexpanded state and the diameter of the expanded area in expanded state is in the range of 0.05mm-0.5mm, preferably in the range of 0.1mm-0.4mm, particularly preferably 0.05, 0.075, 0.1, 0.15, 0.2, 0.25, 0.3 or 0.4, or in any range defined by the above values.

Preferably, the mounting sleeve includes a plurality of slots extending generally along the longitudinal axis, the slots being circumferentially arranged relative to the longitudinal axis to form the expansion zone. The fins or ribs are respectively formed in the radial direction and can be expanded in the radial direction. Thus, each individual fin or rib may be bent independently, since the grooves are provided, and the fins or ribs are not connected to each other in the circumferential direction.

Preferably, the slot is in fluid communication with the heating fluid channel. Thus, the groove may also serve as a passage opening for a heating fluid passage, through which the heating fluid is supplied towards the inner surface of the hollow cylindrical object, wherein preferably the heating fluid is guided into a gap formed between the outer surface of the mounting sleeve and the inner surface of the hollow cylindrical object.

Preferably, the slot is provided as an elongated opening extending in the direction of the longitudinal axis and/or exhibits a sinusoidal shape extending in the direction of the longitudinal axis.

According to a preferred embodiment, the groove may not extend over the entire length of the mounting sleeve with respect to the longitudinal axis, but may be arranged in the direction of the longitudinal axis between a first end of the mounting sleeve, e.g. an upper end, such as a portion adjacent to a cover portion, and a second end of the mounting sleeve, e.g. a lower end. Thus, according to this alternative embodiment, the mounting sleeve may comprise an end portion which is rigid relative to the expansion region, which end portion is thus substantially not radially expanded due to radial forces exerted on the sleeve wedge structure via the core wedge structure. Thus, the expanded area provided by the slot extends between the first end and the second end.

According to a preferred embodiment, the plurality of grooves are arranged such that in the expansion region the mounting sleeve comprises a plurality of ribs extending in the longitudinal direction.

Preferably, the one or more ribs comprise spacers, wherein preferably each rib comprises a spacer. Preferably, the spacer comprises the form of a thin lug (legs) or slat (slats) extending along the longitudinal axis. When the spacer comprises a wave shape or a sinusoidal shape, respectively, a particularly uniform pressure distribution over the hollow cylindrical object and a uniform heat distribution of the heating fluid in the gap provided by the spacer can be obtained.

According to a preferred embodiment, the heating device comprises a flow generating unit, preferably a pump or a fan, for providing a fluid flow, preferably an air flow, in the heating device. Thus, a stable fluid flow may be provided inside the heating device, on the hollow cylindrical object, inside the mandrel and/or in the gap between the mounting sleeve and the hollow cylindrical object.

When the heating device comprises a fluid return conduit for redirecting fluid from the mandrel to the heating unit, fluid that has been used for heating the hollow cylindrical object may be collected and redirected to the heating unit. Thus, the fluid that has been heated only needs to be restored to the predetermined heating temperature. This may avoid complete heating of the new fluid, e.g. ambient air.

Preferably, the fluid, preferably air, is heated to a temperature range between 45 ℃ and 65 ℃, preferably between 50 ℃ and 60 ℃, and particularly preferably to an average temperature comprising 50 ℃, 51 ℃, 52 ℃, 53 ℃, 54 ℃, 55 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃, or 60 ℃.

Preferably, the temperature sensor is arranged for determining the temperature of the heated fluid. The temperature sensor is preferably arranged between the heating unit and the mandrel, wherein preferably the temperature sensor is arranged close to a fluid inlet provided at the mandrel.

According to another preferred embodiment, the mandrel is rotatably supported on the support member, wherein the mandrel is rotatable about the longitudinal axis. Thus, the hollow cylindrical object may be positioned to apply a printing activity according to any desired orientation of the print head of the printing system.

Preferably, the heating device comprises the heating region arranged adjacent to the mandrel for heating the outer side surface of the hollow cylindrical object. Thus, by rotating the hollow cylindrical object around the longitudinal axis, a uniform heating of the side surface of the hollow cylindrical object may be achieved.

According to a preferred embodiment, a plurality of mandrels is arranged on the support member in a circumferential direction around a central axis, wherein preferably the support member is rotatable around the central axis. Thereby, a plurality of hollow cylindrical objects can be handled by means of one mounting device. The output of a printing system comprising a mounting device of such design may accordingly be higher than the output of a printing system comprising a mounting device comprising only one mandrel.

In order to enable printing on the top surface of the hollow cylindrical object and on the side surfaces of the hollow cylindrical object, the mounting means may comprise tilting means for tilting the support member with respect to a reference plane.

According to another preferred embodiment, the heating device comprises a connection unit for connection to an external heat source. Therefore, the mounting device can be designed to include a lightweight design and a simple structure.

According to another preferred embodiment, the mounting device further comprises a battery and/or a contact unit, the contact unit preferably comprising a sliding contact, preferably a brush, for electrical connection with a power source. Thereby, electrical energy may be supplied to components of the mounting device, for example heating means and/or drive means, such as an electric motor for rotating the spindle and/or the support member and/or for tilting the support member.

According to another aspect, a printing system for printing on a hollow cylindrical object, preferably a screw cap, is proposed, the printing system comprising at least one mounting device according to any one of the preceding claims, and at least one printing head configured to print on a surface of the cylindrical object, preferably the screw cap.

The printing system similarly achieves the advantages and effects described above with respect to the mounting device.

Preferably, the at least one print head is configured for printing an aqueous ink.

Drawings

The above and other features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments of the invention, which proceeds with reference to the accompanying drawings, in which reference numerals refer to the features, and wherein:

FIG. 1 is a schematic perspective side view of a mounting device for holding a plurality of hollow cylindrical objects;

FIG. 2 schematically illustrates a perspective cross-sectional view taken from the mounting device of FIG. 1;

fig. 3 schematically shows a perspective cross-sectional view of the mounting device according to fig. 1 and 2;

fig. 4 schematically shows a perspective side view of the mounting device according to fig. 1 to 3;

fig. 5 schematically shows a perspective cross-sectional view of a mandrel of a mounting device according to the embodiment shown in fig. 1 to 4; and

fig. 6 schematically shows a perspective side view of the mandrel of fig. 5.

Detailed Description

Those of skill in the art will appreciate that these embodiments and items are merely illustrative of various embodiments. Thus, the embodiments shown in the present invention should not be construed as limiting, but also include any combination and configuration of the features described within the scope of the present invention.

Fig. 1 schematically shows a perspective side view of a mounting device 1 for holding a plurality of hollow cylindrical objects 6 (here in the form of screw caps) in a printing system. The mounting device 1 comprises a support member 7 and a plurality of mandrels 2 for receiving the hollow cylindrical objects 6, which plurality of mandrels 2 are arranged at the support member 7 in a circumferential direction with respect to a central axis 9 of the mounting device 1. Each spindle 2 is rotatable relative to the support member 7 about a longitudinal axis 10 by means of a bearing 8 (see fig. 5).

The mounting device 1 further comprises heating means 5, which heating means 5 are used to heat a hollow cylindrical object 6 mounted at the mandrel 2. As will be described in more detail below, the heating device 5 according to the present exemplary embodiment is configured to heat the hollow cylindrical object 6 from the outside of the hollow cylindrical object 6 and from the inside of the hollow cylindrical object 6. The heating device 50 is arranged substantially radially inwards with respect to the circumferential arrangement of the plurality of mandrels 2

Fig. 2 schematically shows a perspective cross-sectional view taken from the mounting device 1 of fig. 1. The heating device 5 comprises an internal heating unit 50 containing a plurality of heating wires 51 arranged in circumferential direction with respect to the central axis 9.

Here, the heating unit 50 is configured to heat a fluid, which is air in the present embodiment. In order to provide the heating unit 50 with an air flow, the heating device 5 comprises a flow generating unit (see fig. 3 and 4) which moves air from the radially inner side of the mounting device 1 towards and through the heating wire 51. The heating wire 51 heats the air substantially by convection as the air passes the heating wire 51.

The heating device 5 further comprises a fluid supply conduit 52 through which a flow of heated fluid heated by the heating wire 51 is supplied to the mandrel 2. In particular, heated air is guided from a heating chamber 57 containing the heating unit 50 via a plurality of ducts 56 into a supply annular chamber 58 and into the heating fluid channel 21 (see fig. 5) of the mandrel. Thus, the conduit 56 and the supply annular chamber 58 generally form the fluid supply conduit 52.

As will be described in more detail with reference to fig. 5 and 6, a flow of heated air is directed through the mandrel 2 to heat the inside of the hollow cylindrical object 6. After the heated air has been guided through the mandrel 2, the heated air leaves the mandrel 2 into a return chamber 59 in fluid communication with the flow generating unit 55, so that the air for heating the hollow cylindrical object 6 can be fed back to the heating unit 50 and can thus be reused for heating the hollow cylindrical object 6. In other words, a substantially closed loop of heated and reheated air flow is created.

According to the present embodiment, the air is heated by the heating unit 50 to a temperature between 50 ℃ and 55 ℃, wherein the temperature is measured by an optional temperature sensor (not shown) near the inlet 21 of the heating fluid channel 21 arranged in the mandrel 2. Alternatively or additionally, the temperature of the outer surface of the hollow cylindrical object 6 may be detected.

Fig. 3 is another schematic perspective sectional view of the mounting device 1 according to fig. 1 and 2, wherein only one mandrel 2 holding a hollow cylindrical object 6 is shown in its circuit. This section is slightly offset with respect to the section shown in fig. 2, so that the closed cycle for the air flow achieved by means of the fluid supply duct 52, the fluid return duct 53 and the flow generating unit 55 can be observed in detail.

Furthermore, the heating device 5 further comprises a heating region 54 arranged adjacent to the lateral outside of the mandrel 6, such that an outside surface 61 of the hollow cylindrical object 6 can be heated from the outside of the hollow cylindrical object 6. A uniform heating effect of the outer side surface 61 of the hollow cylindrical object 6 can be achieved by rotating the hollow cylindrical object 6 about the longitudinal axis 10. Thus, the heat radiated by the heating zone 54 toward the hollow cylindrical object 6 is then absorbed by the entire outer side surface 61. The heating zone 54 is thus responsible for heating or tempering the outer side surface 61 of the hollow cylindrical object 6.

In other words, the hollow cylindrical object 6 is heated from the inside and the outside of the hollow cylindrical object 6 by the heating device 5.

Fig. 4 schematically shows a perspective side view of the mounting device 1 according to the previous figures, wherein the heating chamber 57 and the mandrel 2 are hidden, thereby making the flow generating unit 55 clear. The flow generating unit 55 comprises a plurality of fans 550 which are evenly distributed in the circumferential direction with respect to the central axis 9.

Fig. 5 is a schematic perspective cross-sectional view of the mandrel 2 of the mounting device 1 according to the embodiment shown in fig. 1 to 4. The mandrel 2 comprises a mounting sleeve 23 in the form of a hollow cylinder, wherein the heating fluid channel 21 is arranged within the mounting sleeve 23. The mounting sleeve 23 includes a plurality of openings 22 in fluid communication with the heating fluid channel 21. Thus, air supplied from the heating chamber 57 via the inlet 210 into the heating fluid channel 21 is guided through the opening 22 and into contact with the inner surface 60 of the hollow cylindrical object 6. As shown in fig. 6 (schematic perspective side view of the mandrel 2), the mounting sleeve 23 comprises a plurality of spacers 25, 25', which plurality of spacers 25, 25' is arranged on the outer surface of the mounting sleeve 23 for providing a gap between the outer surface of the mounting sleeve 23 and the inner surface 60 of the hollow cylindrical object 6. The spacers 25, 25' are arranged on the outer side surface of the mounting sleeve 23 and on the outer end face of the mounting sleeve 23, which outer end face is provided by the cover 24 of the mounting sleeve 23. The gap thus extends over the end face and the side face of the mounting sleeve 23.

Thus, the heated air supplied into the gap via the opening 22 is in contact with a large part of the inner surface 60 of the hollow cylindrical object 6, since the mounting sleeve is in contact with the hollow cylindrical object 6 only via the spacers 25, 25'.

Thus, an air flow 11 is generated which enters the heating fluid channel 21 through the inlet 210 to enter the mandrel 2 and is further guided through the openings 25, 25' into the gap between the mounting sleeve 23 and the hollow cylindrical object 6. As air is continuously supplied to the mandrel, the air present in the gap is pushed towards the lower end of the hollow cylindrical object 6 and the outlet 212 of the air stream 11. Thus, the heated air heats the inner surface 60 of the hollow cylindrical object 6 by convection and then exits the mandrel 2. Thereby, a substantially uniform heating of the hollow cylindrical object 6 may be obtained.

Since the above-mentioned air flow 11 will remove the hollow cylindrical object 6 from the mandrel 2 if the hollow cylindrical object 6 is not held in place on the mandrel 2, the mandrel 2 comprises an expansion region 26 which can be expanded in radial direction with respect to the longitudinal axis 10, so that the outer diameter of the expansion region 26 can be increased and decreased. The mandrel 2 further comprises a core 3 arranged within the mounting sleeve 23, wherein the core 3 is movable in the direction of the longitudinal axis 10 relative to the mounting sleeve 23. The core 3 is configured to be positioned relative to the mounting sleeve 23 at a first location of the core 3 where the expanded region 26 is in an unexpanded state, and the core 3 is configured to be positioned relative to the mounting sleeve 23 at a second location of the core 3 (as shown in fig. 5) where the core 3 exerts a radial force on the expanded region 26 such that the expanded region 26 is radially expanded relative to the expanded region 26 in the unexpanded state.

In the unexpanded state, the mounting sleeve 23 has a maximum outer diameter which is slightly smaller than the inner diameter of the hollow cylindrical object 6 to be received by the mandrel 2, and in the expanded state, the mounting sleeve 23 has a maximum outer diameter which is larger than the inner diameter of the cylindrical object 6 to be received by the mandrel. Due to the expansion of the expansion region 26, the mounting sleeve 23 exerts a radial force on the cylindrical side wall of the hollow cylindrical object 6, so that a friction fit is created between the outer surface of the spacer 25 arranged in the expansion region 26 and the inner side surface 60 of the hollow cylindrical object 6, thereby holding the hollow cylindrical object 6 firmly in place on the mandrel 2.

The core 3 is located within the mounting sleeve 23. It comprises a core wedge structure 30, the core wedge structure 30 being formed by a plurality of wedge ring segments 300 arranged adjacent to each other along the longitudinal axis 10. The core wedge structure 30 is designed to conform to a plurality of wedge ring segments 290 of the sleeve wedge structure 29 arranged on the inner side of the cylindrical mounting sleeve 23 in the expansion region 26. The core ring segment 300 includes contact surfaces that are capable of contacting complementarily formed contact surfaces of the wedge ring segment 290 of the mounting sleeve 23. The contact surface 37 and the longitudinal axis 10 thus form an angle which, according to the present embodiment, is 17 °. Alternatively, the angle may be other values, preferably between 1 ° and 40 °.

According to the present embodiment, the mounting sleeve 23 comprises a plurality of grooves 27 extending substantially along the longitudinal axis 10, which are arranged in a circumferential direction with respect to the longitudinal axis 10 to form the expansion region 26. The groove 27 is in fluid communication with the heating fluid channel 21, and thus the groove 27 also forms and serves as the opening 25.

As shown in fig. 6, the grooves 27 are arranged such that in the expansion region 26 the mounting sleeve 23 comprises a plurality of ribs 28 extending along the longitudinal axis 10. Thus, since the grooves 27 are provided, the fins or ribs 28 are not connected to each other in the circumferential direction, and each individual fin or rib 28 can be bent independently.

The groove 27 according to this alternative embodiment does not extend over the entire length of the mounting sleeve 23 relative to the longitudinal axis 10, but is arranged in the direction of the longitudinal axis 10 between a first end of the mounting sleeve 23 (with reference to the orientation of the mounting sleeve 23 in fig. 6, corresponding to the right end of the mounting sleeve 23) and a second end of the mounting sleeve 23 (with reference to the orientation of the mounting sleeve 23 in fig. 6, corresponding to the left end of the mounting sleeve 23). Thus, in this alternative embodiment, the mounting sleeve 23 comprises ends that are rigid relative to the expansion region 26, and therefore these ends are not substantially radially expanded by the radial forces exerted on the sleeve 23 via the core 3.

In order to provide a particularly uniform pressure distribution on the hollow cylindrical object 6 by means of the expansion region 26, each groove 27 and thus each rib 28 comprises a wave-like shape. Furthermore, each rib 28 comprises a spacer 25, the spacers 25 also comprising a substantially wave-like shape.

Here, the core 3 is biased to the second position as shown in fig. 5 by a biasing member 31, which in this embodiment comprises the form of a helical compression spring. By actuating the actuator 32, the core 3 can be moved relative to the mounting sleeve 23 against the biasing force of the biasing member 31.

The mounting device 1 further comprises an optional battery (not shown) and an optional contact unit (not shown) comprising sliding contacts, preferably brushes, for electrical connection with a power source.

It is obvious to a person skilled in the art that these embodiments and items only describe examples of the many possibilities. Thus, the embodiments illustrated herein should not be construed as limiting such features and configurations. Any possible combination and configuration of the features may be selected in accordance with the scope of the invention.

List of reference numerals

1 mounting device

2 mandrel

21 heating fluid channel

210 inlet

211 return channel

212 outlet port

22 opening

23 mounting sleeve

24 cover

25 spacer

26 expanded region

27 groove

28 Ribs

29 sleeve wedge structure

290 wedge ring segment

3 core part

30 core wedge structure

300 wedge ring section

31 biasing member

32 actuator

4 cover

5 heating device

50 internal heating unit

51 heating wire

52 fluid supply conduit

53 fluid return conduit

54 heating zone

55 flow generating unit

550 fan

56 pipeline

57 heating chamber

58 feed annular chamber

59 return chamber

6 hollow cylindrical object

60 inner surface

61 side surface

62 top surface

7 support member

8 bearing

9 central axis

10 longitudinal axis

11 air flow