Printing system with a first and second receiving means

Abstract

The invention relates to a printing system comprising a main body and a printing unit for printing a material web by outputting ink droplets, which printing unit is arranged spaced apart from the main body, as well as comprising a first and second receiving means, wherein, when brought into the printing position, the first or second receiving means allows for a positioning of the material web within the active range of the printing unit, wherein the main body has a supporting frame on which means are mounted for moving the material web in the transport direction into the active range of the printing unit and back out of the active range, wherein the main body is designed in such a way that the first receiving means can be moved between a printing position within the active range of the printing unit, in which printing position the first receiving means can be blocked against movement by first and third locking means, and a first resting position within the main body, and in such a way that the second receiving means can be moved between a printing position within the active range of the printing unit, in which printing position the second receiving means can be blocked against movement by second and fourth locking means, and a second resting position within the main body, wherein, when printing the material web with the printing unit, the first or the second receiving means are brought into the printing position and blocked against movement by the corresponding locking means.

Description

[0001] Printing system with a first and second receiving means

[0002] The present invention relates to a printing system with a first and second receiving means according to the preamble of claim 1.

[0003] In the prior art, an inkjet printing device with a device for absorbing ink is known from WO02 / 22362A2.In particular, an inkjet printing device for roll and sheet media, flexible and rigid as well as impermeable and porous media is disclosed, comprising (a) a raising and lowering print head arrangement with at least one print head for printing on the medium, (b) a raising and lowering print table over which the medium to be printed is guided at the time of printing, (c) an ink collecting device which can be used in the region of the print table and which consists of an ink absorption pad and two supporting edges arranged laterally therefrom, and (d) a plurality of separately controllable rollers which can be used as transport and / or feed and / or braking rollers and which transport the medium to be printed and / or advance it by a defined feed length and / or brake it in order to apply tensile stress to it.

[0004] When the ink absorption pad is in new condition, it is possible to prevent contamination from ink droplets from the print bed beneath the porous medium because the ink droplets passing through the porous medium during printing are absorbed and stored inside the pad thanks to the ink absorption pad. However, once the pad is saturated with ink, it loses its contamination-preventing effect, so that further ink droplets passing through the porous medium hit the unabsorbed ink and rebound. This creates a mist of ink droplets that contaminates the print bed, the print bed, and the printhead assembly. Furthermore, ink absorption pads have a very limited ink absorption capacity, so they must be replaced regularly and at relatively short intervals. Such pads, however, are very expensive.

[0005] In an alternative embodiment of the above-described inkjet printing device known from the prior art, the ink collection device insertable in the area of ​​the printing table comprises a non-absorbent ink pad instead of the ink absorption pad. Therefore, if the same amount of ink is to be absorbed with an ink pad as with the ink absorption pad, the distance between the material web and the side of the ink pad facing it must be greater than with the ink absorption pad. This is simply because ink that has passed through the material web is deposited on the pad instead of in the pad.Such ink insert pads are suitable, for example, when curable ink, in particular UV-curable ink, is used, since this can be stacked to form a stack of cured layers and stored in this form when the ink applied to the medium is cured with UV radiation, whereby the ink applied to the insert pad is also cured.

[0006] However, such an ink pad has the disadvantage that, due to its lack of absorbency, it tends to produce increased mist. In order to absorb a large amount of ink, a brand-new ink pad must be placed at a relatively large distance, typically greater than 5 mm to approximately 15 mm, below the material web. The greater the distance, the greater the amount of cured ink that can be stacked and stored. As the distance increases, mist naturally increases. If a technician fails to replace an older ink pad in a timely manner, the underside of the mesh-like material web comes into direct contact with the stacked, cured layers of ink and becomes contaminated. Accordingly, the ink absorption capacity of such pads is also very limited.

[0007] The document DE202019100635U1, which is considered to be the closest prior art, describes an inkjet printer with an ink collection device that enables the service life of the ink collection device to be increased.In particular, this prior art document discloses an inkjet printer with an ink collecting device removably inserted therein, comprising: (A) a printing table with a support plane for receiving a material web and a printing module spaced apart from the printing table with at least one row of nozzles for printing the material web with ink droplets, wherein the printing module defines a printing action zone; (B) a guide unit which provides a net-like material web and comprises first means for guiding it to the printing action zone between the printing table and the printing module and subsequently storing it; wherein the ink collecting device is removably inserted in the printing action zone between the printing table and the net-like material web for collecting the ink droplets which pass through the net-like material web during printing.

[0008] The ink collecting device disclosed in DE202019100635U1 has an endless conveyor belt and a cleaning unit for removing the ink drops caught on the endless conveyor belt, wherein the endless conveyor belt is designed with two deflection rollers, an upper run for collecting the ink and a lower run, and wherein the ink collecting device comprises two supporting edges which are arranged such that the net-like material web is guided from the upper run at a distance greater than zero, wherein the ink collecting device comprises a motor and the inkjet printer is designed such that at least one of the deflection rollers is driven by the motor at least temporarily, preferably all the time, during printing.The disadvantage here is the lengthy conversion work required for installing the ink catcher in the inkjet printer near the print bed and subsequently removing it from the inkjet printer. Efficiency in installing and removing the ink catcher can only be achieved with specialist knowledge, which is carried out by trained and experienced specialists. Furthermore, sufficient space should be available, ideally next to the inkjet printer, for storing the removed ink catcher until it is needed again, so that the specialist personnel can save time traveling to and from the storage area. The ink catcher and the print bed are each examples of a support device for positioning a material web.

[0009] It would therefore be desirable to have a printing system available which would enable a saving of set-up time when converting it from a first receiving means in printing position to a second receiving means in printing position and vice versa.

[0010] The present invention is therefore based on the general object of providing a printing system which enables a saving of set-up time when converting the same from a first receiving means in the printing position to a second receiving means in the printing position and vice versa.

[0011] According to the invention, the object is achieved with a printing system comprising the features of claim 1. The respective subclaims relate to further advantageous and possibly additionally inventive embodiments.

[0012] The printing system according to the present invention is a printing system with a base body and a printing unit for printing a material web by ejecting ink drops, which printing unit is arranged at a distance relative to the base body, and a first and second receiving means, wherein the first and / or second receiving means, when brought into the printing position, enables the material web to be positioned in the effective range of the printing unit, wherein the base body comprises a support frame, on which support frame means are mounted for bringing the material web in the transport direction into the effective range of the printing unit and out of the effective range again.

[0013] According to the invention, the base body is designed in such a way that the first receiving means can be moved between a printing position in the effective range of the printing unit, in which printing position the first receiving means can be blocked against movement by first and third locking means, and a first rest position within the base body, and that the second receiving means can be moved between a printing position in the effective range of the printing unit, in which printing position the second receiving means can be blocked against movement by second and fourth locking means, and a second rest position within the base body, wherein when the material web is printed with the printing unit, the first or the second receiving means is moved into the printing position and blocked against movement by the corresponding locking means.

[0014] According to a preferred embodiment, the first receiving means can be blocked against movement in the printing position by first locking means attached to the support frame, which are designed to engage with third locking means attached to the first receiving means, and the second receiving means can be blocked against movement in the printing position by second locking means attached to the support frame, which are designed to engage with fourth locking means attached to the second receiving means.

[0015] The first and third locking means are preferably designed as corresponding locking elements. The second and fourth locking means are also preferably designed as corresponding locking elements. Here, one locking element can be designed, for example, as a groove, recess, or opening, into which the other locking elements related to the one engage, which are preferably each designed as a pin or bolt. Particularly preferably, one locking element is designed for releasable, positive engagement with the other locking element.

[0016] The corresponding locking means allow the first or second holding means to be held securely in the desired printing position.

[0017] According to a preferred embodiment, the base body comprises two mutually parallel slide rails which carry the second receiving means at its opposite ends and which, outside the effective range of the printing unit, extend at least in sections at an angle in the range of 10 degrees to 35 degrees, preferably in the range of 12 degrees to 24 degrees, particularly preferably in the range of 15 degrees to 21 degrees downwards and in or against the transport direction of the material web, in such a way that the second receiving means provided with guide elements can be moved onto and along the slide rails from its printing position to the second rest position manually or automatically by suitable first adjustment means, and wherein the second receiving means can be moved by means of a pneumatic or motorized lifting system at least substantially in the vertical direction, preferably in the vertical direction,between its printing position and the first rest position, which is lowered relative to its printing position. The combination of the slide rails and the lifting system offers the advantage that the printing system can be implemented in a compact, simple, and cost-effective design, and the second support device can be adjusted between both positions with great ease.

[0018] When reference is made to an angle of one degree in this description, this means the 360th part of a full angle of 360°. When reference is made to a vertical direction in this description, this means the direction of gravity. A "substantially vertical direction" means that a corresponding direction allows an angle of inclination relative to the vertical direction, with this angle of inclination being no more than 10 degrees, in particular no more than 5 degrees. A fictitious horizontal plane is understood to be a plane oriented perpendicular to the direction of gravity.

[0019] In a highly preferred embodiment, the slide rails extend horizontally in or against the transport direction of the material web, at least within the effective area of ​​the printing unit. This refinement offers the advantage that moving the second receiving means, particularly from the second rest position to its printing position, is even easier.

[0020] The two parallel slide rails can each be part of the supporting structure or can each be mounted on the supporting structure.

[0021] The pneumatic lifting system can typically have at least two or at least four synchronously extendable and retractable pneumatic cylinders.

[0022] The guide elements may comprise wheels mounted on the second receiving means.

[0023] According to a preferred embodiment, the first receiving means is an ink collecting device, and the second receiving means is a suction table that can be subjected to negative pressure. According to an alternative preferred embodiment, the first receiving means is a suction table that can be subjected to negative pressure, and the second receiving means is an ink collecting device. These developments have the advantage that the printing system can be used without difficulty for both mesh-like material webs and impermeable material webs.

[0024] Both the first and second receiving means can be elongated, with their longitudinal axes preferably aligned transversely to the transport direction of the material web. The length of the respective receiving means along the longitudinal axis can be 1.5 meters to 5 meters, preferably 3 meters to 5 meters. An impermeable material web is understood to be a material web impermeable to ink droplets, in which ink droplets that impinge on the material web during printing do not partially penetrate directly through it, as is the case with a net-like material web. A net-like material web can, for example, be a mesh material web.

[0025] According to a further preferred embodiment, the ink collecting device comprises an endless conveyor belt circulating between two deflection rollers for collecting and transporting away the ink drops passing through a net-like material web when printing said web, as well as two guide edges which are arranged transversely to the transport direction of the material web and on each opposite side of the conveyor belt along the conveyor belt, such that the net-like material web can be guided from the strand of the conveyor belt facing directly onto the net-like material web at a distance greater than zero in the transport direction of the material web when the net-like material web is under tensile stress in the transport direction, wherein the conveyor belt can be driven by at least one of the two deflection rollers, which deflection roller is connected to a motor.

[0026] In a preferred embodiment of the printing system, the two leading edges are arranged such that the mesh-like material web is guided from the strand directly facing the mesh-like material web at a distance of 1 mm to 5 mm, preferably at a distance of 1 mm to 4 mm, and most preferably at a distance of 2 mm to 3 mm. This allows the formation of ink mist to be kept at a consistently low and acceptable level.

[0027] The ink collection device can comprise a cleaning unit for removing ink from the conveyor belt. According to a particularly preferred embodiment, the cleaning unit comprises a blade with a cutting edge, wherein the cleaning unit is arranged on one of the deflection rollers such that when the conveyor belt runs over the at least one deflection roller and ink droplets collected on the conveyor belt harden or dry out, the cutting edge can scrape the hardened or dried ink droplets from the conveyor belt.

[0028] The printing system can be configured to move the printing unit bidirectionally via the first or second receiving means along a scanning axis oriented transversely to the transport direction of the material web, in order to print the material web with ink droplets in one or both of the corresponding directions along the scanning axis, thereby defining the effective area of ​​the printing unit. The base body can comprise, in the inlet area and / or the outlet area of ​​the printing unit, at least one plate facing the printing unit, which at least partially encloses the effective area of ​​the printing unit and forms an upper side of the base body.

[0029] According to a very preferred embodiment, the plate has a flap in the inlet area or in the outlet area that can be opened away from the effective area of ​​the printing unit and can be moved between a closed position and an open position such that, in the open position, the second receiving means is provided with access to the second rest position under the flap, and in the closed position, the second receiving means remains blocked from access to the second rest position by the flap. This further development has the advantage of increasing the reliability of correct positioning of the material web around the effective area of ​​the printing unit and, in addition, the interior of the base body can be at least partially protected from the penetration of contaminating particles from the ambient air.

[0030] The inlet area is the area where the plate is located and through which the material web enters the effective area of ​​the printing unit. Similarly, the outlet area is the area where the plate is located and through which the material web exits the effective area of ​​the printing unit.

[0031] Typically, the leading edges of the ink catcher or the surface of the suction table to which negative pressure can be applied when the ink catcher or the suction table is in the printing position are arranged higher than the surface of the plate facing the printing unit, preferably by two to ten millimeters, more preferably by two to five millimeters, and most preferably by two to three millimeters higher than the surface of the plate facing the printing unit. This makes it possible to reduce any friction between the underside of the material web, opposite the front side of the material web to be printed, and the plate, which in turn can reduce the risk of abrasion of the ink image printed on the underside, this is the case with two-sided printing.

[0032] Alternatively, the corresponding guide edges or the surface of the suction table can be arranged flush with the surface of the plate.

[0033] Means for moving the material web in the transport direction into the effective area of ​​the printing unit and out of the effective area again can comprise several separately controllable rollers which can be used as transport and / or feed and / or braking rollers and which transport the material web and / or advance it by a defined feed length in the transport direction and / or brake it in order to apply a tensile stress to it.

[0034] In a preferred embodiment, the printing system comprises a collection container associated with the cleaning unit for collecting the ink removed by the cleaning unit.

[0035] According to a particularly preferred embodiment, the printing system is a drop-on-demand inkjet printing system. In a particularly preferred embodiment, the printing system comprises second adjustment means designed to move the printing unit perpendicular to the material web positioned in the effective range of the printing unit, i.e., in the direction of gravity, in order to adjust the height between the printing unit and the material web in the effective range of the printing unit.

Claims

Claims 1. Printing system comprising a base body and a printing unit for printing a material web by ejecting ink droplets, the printing unit being arranged at a distance relative to the base body, and a first and second receiving means, wherein the first or second receiving means, when in the printing position, enables the positioning of the material web within the effective area of ​​the printing unit, wherein the base body comprises a support frame on which means are mounted for moving the material web in the transport direction into and out of the effective area of ​​the printing unit, characterized in that the base body is designed such that the first receiving means can be locked against movement between a printing position within the effective area of ​​the printing unit, in which printing position the first receiving means can be locked against movement by first and third locking means.and can be moved to a first rest position within the base body, and that the second receiving means can be moved between a pressure position in the area of ​​effect of the pressure unit, in which pressure position the second receiving means can be blocked against movement by the second and fourth locking means, and a second rest position within the base body, wherein when printing the material web with the pressure unit the first or the second receiving means is moved into pressure position and blocked against movement by the corresponding locking means.

2. Pressure system according to claim 1 characterized in that the first receiving means in the pressure position can be blocked against movement by first locking means attached to the support frame, which are designed to engage with third locking means attached to the first receiving means, and that the second receiving means in the pressure position can be blocked against movement by second locking means attached to the support frame, which are designed to engage with fourth locking means attached to the second receiving means.

3. Printing system according to claim 1 or 2, characterized in that the base body comprises two mutually parallel guide rails which support the second receiving means at its opposite ends, and which extend downwards, at least sectionally, outside the effective area of ​​the printing unit, relative to an imaginary horizontal plane at an angle in the range of 10 degrees to 35 degrees, preferably in the range of 12 degrees to 24 degrees, particularly preferably in the range of 15 degrees to 21 degrees, in or against the transport direction of the material web, such that the second receiving means, provided with guide elements, can be moved manually or automatically by suitable first adjusting means onto and along the guide rails from its printing position to the second rest position, and wherein the second receiving means is moved at least substantially in a vertical direction by means of a pneumatic or motorized lifting system.preferably in a vertical position, direction, between its printing position and the first rest position lowered relative to its printing position. Printing system according to claim 3, characterized in that the guide rails extend horizontally in or against the transport direction of the material web, at least in the area of ​​operation of the printing unit. Printing system according to claim 3 or 4, characterized in that the guide elements comprise wheels mounted on the second receiving means. Printing system according to at least one of the preceding claims, characterized in that the first receiving means is an ink collecting device and the second receiving means is a suction table subjected to negative pressure, or that the first receiving means is a suction table subjected to negative pressure and the second receiving means is an ink collecting device.Printing system according to claim 6, characterized in that the ink collection device comprises an endless conveyor belt circulating between two deflection rollers for collecting and transporting the ink droplets passing through a net-like material web during printing, as well as two guide edges arranged transversely to the transport direction of the material web and on opposite sides of the conveyor belt, such that the net-like material web can be guided by the section of the conveyor belt facing directly onto the net-like material web at a distance greater than zero in the transport direction of the material web when the net-like material web is under tensile tension in the transport direction, wherein the conveyor belt can be driven at least via one of the two deflection rollers, which deflection roller is connected to a motor.Printing system according to claim 7, characterized in that the ink collection device comprises a cleaning unit for removing ink from the conveyor belt. Printing system according to claim 8, characterized in that the cleaning unit comprises a blade with a cutting edge, wherein the cleaning unit is arranged on one of the deflection rollers such that when the conveyor belt runs over the at least one deflection roller and ink droplets collected on the conveyor belt harden or dry, the cutting edge can scrape hardened or dried ink droplets from the conveyor belt. Printing system according to claim 3 or according to at least one of claims 4 to 9 relating to claim 3, characterized in that the base body in the inlet area and / or in the outlet area of ​​the printing unit comprises at least one plate facing the printing unit, which at least partially encloses the effective area of ​​the printing unit and which has a top surface. The basic body is formed, wherein the plate has a flap in the inlet or outlet area that can be opened away from the area of ​​effect of the pressure unit and that can be moved between a closed position and an open position, such that in the open position the second receiving means is granted access to the second rest position under the flap, and in the closed position the second receiving means is prevented from accessing the second rest position by the flap. The pressure system according to claim 7 or according to at least one of claims 8 to 10 relating to claim 7 is characterized in that the net-like material web is a mesh material web.Printing system according to at least one of the preceding claims characterized in that the guide edges of the ink collection device or the surface of the suction table subjected to negative pressure are arranged higher than the surface of the plate facing the printing unit, preferably by two millimeters to ten millimeters, particularly preferably by two millimeters to five millimeters, most preferably by two millimeters to three millimeters.