EP3693175A2 - Device and method for printing a print substrate - Google Patents

Abstract

The invention relates to a device and a method for printing on a printing substrate (1). A print head shuttle (5) with at least one print head (14a, 14b) applies a print medium to a print substrate (1) to generate a print image, the print substrate (1) being a web material which can be displaced along a web path in a feed direction (4) is. The print head shuttle (5) is arranged on a first side of the print substrate (1), while a printing table (3) with a support surface (13) is arranged opposite the print head shuttle (5) on a second side of the print substrate (1). A holding device (11) is provided to hold the printing substrate (1) in such a way that a relative movement between the printing table (3) and the printing substrate (1) is prevented for printing. The print head shuttle (5) has a smoothing device (16) which comes into contact with the support surface (13) of the printing table and is moved over at least part of the support surface (13) in such a way that it moves over a surface on the support surface (13 ) of the printing table (3) arranged printing substrate (1) strokes in order to smooth it.

Description

The invention relates to a device and a method for printing on a printing substrate.

background

When printing a material in a printing device or a printing system, the material can be provided as a continuous material on a roll. Alternatively, provision can be made for individual sheets to be fed to the printing device one after the other in order to print the sheets individually. When printing on continuous material, the continuous material can be separated after printing in order to obtain individual printed sheets.

The document DE 10 2016 102 565 A1 discloses a method and apparatus for producing a singulated sheet for a printing device. In the method, various sheet materials are provided as continuous material in magazine or buffer devices, with a transport path to a material switch, in which the transport paths converge, being located downstream of the magazine devices on the output side. Transport devices are provided which are each assigned to one of the transport paths and are set up to transport the various sheet materials from the magazine device at least to the material switch. Control signals are received in the transport devices which determine a material selection corresponding to a print job for a selected one of the sheet materials. The transport devices are controlled according to the control signals in such a way that the selected sheet material is transported to the material switch and in the material switch passes from the transport path into a feed path into which the transport paths open. The selected sheet material is transported by means of the transport devices via the feed path from the material switch to a separating device. In the separating device, a separated sheet is produced for subsequent printing in that the separated sheet is separated from the selected sheet material.

In the document DE 10 2016 102 566 A1 describes a method and a device for printing an isolated sheet.

The document US 2010/0271453 A1 describes a recording apparatus having a recording head for performing a recording operation by ejecting ink on a recording surface of a recording medium while moving, a transport section for transporting the recording medium along a transport path passing through a recording area in which the recording head performs the recording operation, a disk arranged in the recording area to move a surface opposite to the recording surface of the Recording medium, and printing members disposed in the recording area and in contact with outer edge portions in a width direction of the recording surface of the recording medium. The pressing members move to press the recording medium on an upstream side and on a downstream side of the recording head with movement of the recording head.

In the document JP 2017-109364 A discloses a printer with a paper guide unit and two paper sensors and a printing method.

The document DE 690 25 124 T2 describes an ink jet printer, document JP H05-162397 A a printer.

The document DE 43 21 177 A1 discloses a device for image inspection and color measurement on at least one printed product that was created in a printing press with at least one printing unit. The device consists of at least one image acquisition device, which supplies image data of the printed product, and of a computing device, the computing device on the one hand determining all image data of the print product for the purpose of an image inspection and on the other hand determining a measured variable for a color assessment from the image data of at least one measuring point (pixel) of the printed product .

In the document DE 10 2010 060 408 A1 describes an arrangement for regulating the web tension of a printing substrate web in a printing device.

To print a continuous material, the continuous material must be transported through the printing device or the printing system, the transport movement being coordinated with the printing process and transport through the entire printing device or the entire printing system must be ensured under suitable conditions, in particular in the area of the printing The relevant components must meet the requirements that result from the printing process itself.

Summary

The object of the invention is to specify a device and a method for printing a print substrate with an improved provision of a print substrate, in particular with regard to avoiding unevenness of the print substrate.

To achieve this, an apparatus and a method for printing a print substrate according to independent claims 1 and 14 are created. Refinements are the subject of dependent subclaims.

According to one aspect, an apparatus for printing on a print substrate is provided. The device has a printhead shuttle with at least one printhead which is configured to apply a printing medium to a printing substrate in order to generate a print image, the printing substrate being a web material which can be displaced along a path, and the printhead shuttle being arranged on a first side of the printing substrate is. A printing table with a support surface is arranged opposite the printing head shuttle on a second side of the printing substrate. The printing table has a holding device which is set up to hold the printing substrate in such a way that a relative movement between the printing table and the printing substrate is prevented for printing. The print head shuttle has a smoothing device which is set up to come into contact with the support surface of the printing table and to be moved over at least part of the support surface in such a way that it sweeps over a print substrate arranged on the support surface of the printing table in order to apply it smooth.

According to a further aspect, a method for printing on a printing substrate is provided. The method comprises: applying a printing medium to a printing substrate, which is a web material which is displaceable along a web path, with at least one print head of a print head shuttle, which is arranged on a first side of the print substrate, for generating a print image; Holding the printing substrate with a holding device of a printing table which is arranged opposite the print head shuttle on a second side of the printing substrate, such that a relative movement between the printing table and the printing substrate is prevented for printing; and smoothing the web material arranged on a support surface of the printing table by means of a smoothing device which brushes over the printing substrate arranged on the support surface of the printing table, by coming into contact with the support surface of the printing table and being moved over at least part of the support surface.

By arranging the print head shuttle on a side of the web material opposite the print table, the print substrate can be printed in particular by means of the print head shuttle while it rests on the print table and is held by the holding device.

The smoothing device, which brushes the print substrate by coming into contact with the support surface of the printing table and is moved over the support surface, can remove unevenness such as wrinkles or bubbles. In this way, the printing process is optimized and the print image can be improved. Unevenness can arise, in particular, as a result of the transport of the printing substrate embodied as a web material, in particular the advance, but also as a result of other factors which affect the way the printing substrate lies on the printing table. For example, heating the printing substrate by a heated printing table can lead to unevenness of the printing substrate, which can be removed by the smoothing device. It goes without saying that, due to the thin design of the web material, the smoothing device comes into contact with the web material which is arranged on the support surface of the printing table when the smoothing device is set up to come into contact with the support surface. Therefore, the coming into contact of the smoothing device with the support surface of the printing table includes coming into contact with the printing substrate, which is optionally arranged on the support surface.

The smoothing device can extend along a longitudinal direction which runs parallel to the feed direction. Here, a functional part of the smoothing device is elongated in the longitudinal direction, that is to say has a greater extent in the longitudinal direction than in other directions. In particular, it can be provided that the smoothing device moves transversely, preferably perpendicular to the feed direction over the support surface of the printing table. Thus, when the smoothing device extends in the longitudinal direction, the smoothing device can have a smoothing effect when it moves over the support surface of the printing table.

The smoothing device can be arranged on the print head shuttle in such a way that the smoothing device moves with the print head shuttle. The smoothing device is preferably at the front of the print head shuttle in relation to a direction of movement of the print head shuttle arranged, that is, when the print head shuttle moves in the printing direction, the smoothing device smooths the print substrate before it is printed. In this way, the smoothing device does not have to be moved separately, but can simply be attached to the print head shuttle and moved with it. When the print head shuttle moves transversely to the direction of advance of the print substrate, the smoothing device then also moves transversely to the direction of advance.

In a preferred embodiment, the smoothing device is movable transversely to a direction of movement of the print head shuttle, preferably up and down relative to the print head shuttle, between a first and a second position. In the first position, the smoothing device can be in contact with the supporting surface of the printing table (or, as explained above, with the printing substrate arranged on the supporting surface of the printing table), so that the smoothing device sweeps over the printing substrate arranged on the supporting surface of the printing table when it moves . Furthermore, in the second position, the smoothing device can be arranged above the printing table in such a way that the smoothing device does not touch the printing substrate, preferably also the printing table, during a movement.

In particular, it can be provided that the smoothing device sweeps over the printing substrate only once before the first printing process. In order not to smear the print image, the smoothing device can then be moved into the second position, in particular raised, so that it no longer touches the print substrate, preferably also the printing table. Alternatively, it is also conceivable that the smoothing device is decoupled from the print head shuttle after the print substrate has been smoothed and remains on the opposite side while the print head shuttle moves back for the further printing process. For a further printing process, the smoothing device can then later be brought back into the starting position on the print head shuttle.

The smoothing device preferably has a length which corresponds to at least one length of the support surface of the printing table. The length of the smoothing device can be equal to or greater than a length of the print head shuttle. This ensures that the entire width of the print substrate is painted over and smoothed. If necessary, however, it can also be provided that only a part of the print substrate is painted.

The smoothing device can comprise a brush or be formed by a brush. In particular, the bristles of the brush can point in the direction of the support surface of the printing table and smooth the printing substrate on the printing table. In this way, a sufficiently strong, but nevertheless gentle contact pressure of the smoothing device on the printing substrate can be achieved. The print substrate is not only pressed smooth, but unevenness is smoothed out. It goes without saying that the smoothing device can alternatively or additionally have other suitable structures, such as a lip, for example a rubber lip or other plastic lip, a sponge or even rigid smoothing body, which, depending on the application, can be rigid or flexible, soft or hard. The smoothing device can possibly be mounted on a spring-loaded basis in order to achieve a suitable contact pressure.

The aforementioned holding device can be set up to hold the print substrate during a feed movement of the print substrate in such a way that a relative movement between the printing table and the print substrate is prevented during the feed movement. The holding device can comprise a vacuum device which sucks the printing substrate onto the printing table by means of a negative pressure or a vacuum. The vacuum device can be connected to the surroundings via channels with a support surface of the printing table, so that the printing substrate is sucked onto the support surface of the printing table by means of the negative pressure in order to hold the printing substrate. A printing substrate held by a suitable negative pressure on the support surface of the printing table can be smoothed out well by the smoothing device described above, in particular in comparison with a firmly clamped printing substrate.

The print head shuttle can be configured to perform a movement in front of and against a direction of shuttle movement running transversely to the direction of movement of the printing substrate for printing. The feed movement of the print substrate and the movement of the print head shuttle can provide a positioning of the print head shuttle above the print substrate, which enables a print image to be generated on the print substrate. Alternatively or additionally, the print head shuttle can be set up to execute a movement in front of and against a parallel shuttle movement direction running parallel to the feed direction of the printing substrate.

The web material can be a film material. The film material can be a plastic film material, for example made of polycarbonate (PC) or polyvinyl chloride (PVC). The sheet material can be a thin sheet material. The thin sheet material can have a material thickness of 100 µm or less. For example, the sheet material can have a thickness of 75 µm. The web material can be provided with a width which corresponds to a desired width of the print image, possibly plus any necessary side margins. For example, the web material can be provided with a width of 300 mm to 600 mm. A storage device can be provided from which the web material is fed to the printing process. For example, the device can comprise a supply roll on which the web material is rolled up and from which the web material is pulled during operation.

The device can furthermore have a first web tension measuring device, which is arranged along the web path in front of the printing table and is configured to generate first measurement data which indicate a mechanical web tension of the printing substrate on the first web tension measuring device, a first tensioning device which is arranged along the web path in front of the printing table and is set up to set a mechanical web tension of the printing substrate, a second web tension measuring device which is arranged along the web path after the printing table and is set up to generate second measurement data which indicate a mechanical web tension of the printing substrate on the second web tension measuring device, and a second tensioning device which runs along of the web path is arranged after the printing table and set up to set a mechanical web tension of the printing substrate, as well as a control device. The control device can be configured to receive the first measurement data, to generate first control data on the basis of the first measurement data and to control the first tensioning device in accordance with the first control data, in such a way that the first tensioning device effects a first predetermined web tension of the printing substrate on the first tensioning device, and the to receive second measurement data, to generate second control data based on the second measurement data and to control the second tensioning device in accordance with the second control data, such that the second tensioning device causes a second predetermined web tension of the printing substrate on the second tensioning device.

The control device can be configured to keep the web tension of the print substrate constant along the web path in front of the printing table and to keep the web tension of the printing substrate constant along the web path behind the printing table during a printing process. Constant printing conditions can thus be ensured, in which the web tension in front of the printing table and the web tension behind the printing table remain constant.

The device may comprise a rejection device. The separating device can comprise a testing device, a packaging device and a document switch. The test device can be formed with an image recording device and set up to record an image of the print image on the web material, to compare the recorded image of the print image on the web material with comparison image data, to determine the print image as a correct print image if based on the comparison of the print image a correspondence between the print image and the comparison image data is determined on the web material with the comparison image data, and to determine the print image as an incorrect print image if, based on the comparison of the print image on the web material with the comparison image data, there is no correspondence between the print image and the comparison image data is determined.

The assembly device can be configured to assemble the web material into individual sheets and the document switch can be configured to guide a made-up sheet onto one of a first transport path and a second transport path, a made-up sheet with a print image which is defined as a correct print image is directed to the first transport path and a made-up sheet with a print image, which was determined to be an incorrect print image, is directed to the second transport path.

A waste device can be arranged along the second transport path, which destroys a finished sheet with a print image which was determined to be an incorrect print image. As a result, reuse of the made-up sheet with a print image which was determined to be an incorrect print image can be excluded. Alternatively or additionally, sensitive data can be made unrecognizable. For example, the waste device can be a cutting device which cuts the finished sheet with a print image that has been determined to be an incorrect print image. The cutting device can cut the sheet into strips. Parameters of the cutting device can be adjustable. For example, a strip width of the cut strips can be adjustable. The destroyed sheet, for example the strips into which the sheet was cut, can be collected in a reject bin. The second transport route can lead into the reject bin.

The configurations explained in connection with the device for printing on a printing substrate can be provided correspondingly in the method for printing on a printing substrate.

Description of exemplary embodiments

• Fig. 1 eine schematische Übersicht einer Druckvorrichtung zum Bedrucken eines Drucksubstrats;
• Fig. 2 eine schematische Übersicht einer Anordnung eines Drucktischs und eines Drucckopfshuttles in einer Druckvorrichtung;
• Fig. 3 eine schematische Übersicht weiterer Ausgestaltungsoptionen einer Druckvorrichtung; und
• Fig. 4 eine schematische Übersicht einer weiteren Druckvorrichtung zum Bedrucken eines Drucksubstrats.

In the following, further exemplary embodiments are explained in more detail with reference to drawings. Here show:

• Fig. 1 a schematic overview of a printing device for printing on a print substrate;
• Fig. 2 a schematic overview of an arrangement of a printing table and a printing head shuttle in a printing device;
• Fig. 3 a schematic overview of further configuration options of a printing device; and
• Fig. 4 a schematic overview of a further printing device for printing on a print substrate.

The Fig.1 shows a printing device for printing on a printing substrate. The printing substrate is a web material 1 on a roll 2, which serves as a storage device for the web material 1. The web material 1 can be a plastic film. In one example, the web material 1 is a polycarbonate film with a thickness of 75 μm and a width of 600 mm. In a further example, the web material can consist of another material, for example PVC, have a greater or lesser thickness, for example 100 μm, and / or have a smaller or greater width, for example 300 mm.

The web material is moved by means of a printing table 3 in a feed direction 4 through the printing device. For this purpose, the printing table 3 can be moved in the feed direction 4 and against the feed direction 4. The printing table 3 is designed as a coherent unit or it moves at least as a unit in order to support a uniform advance of the web material 1 over the width of the web material 1. The printing table 3 has a holding device by means of which the web material 1 is held. While the web material 1 is held on the printing table 3 by means of the holding device, the printing table moves in the feed direction 4 from a rear position to a front position and thus pulls the web material 1 from the roll 2 in the feed direction 4 by the printing device. The holding device then releases the web material 1 so that it is released from the printing table 3. The printing table 3 then moves against the feed direction 4 past the web material 1 from the front to the rear position and then forms contact again with the web material 1 by means of the holding device, whereupon the movement of the printing table 3 in the feed direction 4 is repeated. A discontinuous advancement of the web material 1 through the printing device is thus provided.

In further refinements, additional drive mechanisms can be provided which support the movement of the web material 1 provided by means of the printing table 3. For example, driven rollers, over which the web material 1 runs and which support the web material 1, can be arranged along a path of the web material 1 in front of and / or behind the printing table 3. In particular, a supporting drive mechanism can be arranged along the path of the web material 1 behind the printing table 3 in order to support a movement of the web material 1 away from the printing table 3.

A printing head shuttle 5 is arranged on a side of the web material 1 opposite the printing table 3. The print head shuttle 5 is arranged opposite the printing table 3 with respect to the web material 1 in such a way that the web material 1 runs between the printing table 3 and the print head shuttle 5 so that it can be printed by means of the print head shuttle 5 while it is resting on the printing table 3 and by the holding device is held. The printing table 3 moves the web material past the print head shuttle 5 in the feed direction 4. During the movement of the web material, the print head shuttle 5 prints the web material 1.

During the movement through the printing device, the web material 1 runs over several deflection rollers 6, by means of which the web material 1 is deflected within the printing device. The web material also runs over web tension measuring rollers 7, by means of which a web tension of the web material 1 is measured. Like in the Fig. 1 As shown, a first web tension measuring roller 7a is arranged along the web path of the web material 1 in front of the printing table. The first web tension measuring roller 7a thus measures the web tension of the web material 1 in front of the printing table 3. By holding the web material 1 by means of the holding device on the printing table 3, a web tension of the web material 1 can occur along the web path of the web material 1 behind the printing table 3, which depends on the Web tension in front of the printing table 3 is independent. For this reason, a second web tension measuring roller 7b is arranged along the path of the web material 1 behind the printing table. The second web tension measuring roller 7b thus measures the web tension of the web material 1 behind the printing table 3. The web tension of the web material 1 causes a respective force on the axes of the web tension measuring rollers 7a, 7b. The respective force on the axis of the web tension measuring rollers 7a, 7b is measured by means of a respective sensor device 8a, 8b of the web tension measuring rollers 7a, 7b. The respective sensor device 8a, 8b of the first 7a and the second 7b web tension measuring roller generates first and second measurement data, respectively, which indicate the respective web tension of the web material 1 on the first web tension measuring roller 7a and on the second web tension measuring roller 7b, respectively.

Furthermore, the web material runs over so-called dancers 9. These are rollers which are movably arranged in order to set a tension of the web material 1. Like in the Fig. 1 A first dancer 9a can be seen along the path of the web material 1 in front of the printing table. The first dancer 9a is movable up and down in the example shown, a downward movement of the first dancer 9a leading to an increase in the tension of the web material 1 and an upward movement of the first dancer 9a to a reduction in the tension of the web material 1 leads. The web tension of the web material 1 in front of the printing table 3 can thus be adjusted by means of the first dancer 9a.

A second dancer 9b is arranged along the path of the web material 1 behind the printing table. In the example shown, the second dancer 9b can also be moved up and down, with a downward movement of the second dancer 9b increasing the tension of the web material 1 and an upward movement of the second dancer 9b reducing the tension of the web material 1 leads. Thus, the web tension of the web material 1 behind the printing table 3 can be adjusted by means of the second dancer 9b, which is independent of the web tension in front of the printing table 3 at least while the web material 1 is being held by the holding device on the printing table 3.

A control device 10 is connected to the web tension measuring rollers 7a, 7b and the dancers 9a, 9b (not shown) and is set up to receive the first and the second measurement data from the web tension measuring rollers 7a, 7b. In the control device 10, the first measurement data are compared with a first predetermined web tension. The first predetermined web tension indicates a desired web tension of the web material 1 along the web path of the web material 1 in front of the printing table. The control device 10 generates first control data corresponding to the comparison result, which are transmitted to the first dancer 9a and lead to a movement of the first dancer 9a. For example, the first control data indicate a small downward movement of the first dancer 9a if the comparison shows that the web tension of the web material on the first web tension measuring roller 7a deviates by a small difference downwards from the first predetermined web tension and the first control data give a larger one Movement of the first dancer 9a upwards when the comparison shows that the web tension of the web material on the first web tension measuring roller 7a deviates by a greater difference upwards from the first predetermined web tension.

The control device 10 is further set up to compare the second measurement data with a second predetermined web tension. The second predetermined web tension indicates a desired web tension of the web material 1 along the web path of the web material 1 behind the printing table. The control device 10 generates second control data corresponding to the comparison result, which are transmitted to the second dancer 9b and lead to a movement of the second dancer 9b. As explained above with regard to the first dancer 9a, for example, the second control data indicate a small downward movement of the second dancer 9b if the comparison shows that the web tension of the web material on the second web tension measuring roller 7b is a small difference downwards from the second predetermined Web tension deviates and the second control data indicate a greater upward movement of the second dancer 9b if the comparison shows that the web tension of the web material on the second web tension measuring roller 7b deviates upwards by a greater difference from the second predetermined web tension.

The web tension in front of and behind the printing table 3 can be continuously monitored by repeatedly receiving first and second measurement data and generating corresponding first and second control data. In this way, regulation of the web tension in the printing device can be provided along the path of the web material 1 both in front of and behind the printing table 3. For example, the first and second predetermined web tension can be the same and the web tension of the web material 1 both in front of and behind the printing table 3 can be regulated in such a way that the same web tension of the web material 1 is achieved within a predetermined permissible deviation in front of and behind the printing table 3.

The Fig. 2 shows an arrangement of a printing table 3 in a printing device on which a web material 1 is arranged. The web material 1 is moved during a movement of the printing table 3 in a feed direction 4 (from the drawing plane of the Fig. 2 out) held on the printing table 3 by means of a holding device, so that the web material 1 is moved along the feed direction 4 through the printing device. In the representation of the Fig. 2 the holding device is provided with a vacuum device 11. The vacuum device 11 generates a negative pressure. Here, the vacuum device 11 is connected to the environment via channels 12 to a support surface 13 of the printing table 3. The web material 1 rests on the support surface 13 of the printing table 3. To hold the web material 1, the vacuum device 11 generates a negative pressure during the movement of the printing table 3 in the feed direction 4, so that the web material is sucked into the support surface 13 via the channels 12 and thus held on the printing table 3.

In order to ensure that the web material 1 is held uniformly on the support surface 13, openings in the channels 12 are distributed over the entire support surface 13. In the example of the Fig. 2 For this purpose, the bearing surface 13 consists of a porous material with a defined porosity, which is connected to the vacuum device 11. The porosity of the material of the bearing surface 13 provides undefined channels 12 which, due to the defined porosity, lead to a uniform suction and holding of the web material 1 on the bearing surface 13. In alternative configurations, the channels 12 can be provided, for example, with a defined grid of bores, for example micro-bores, in order to ensure that the web material 1 is evenly sucked in and held on the support surface 13. Apart from the openings of the channels 12 in the support surface 13 or the porosity of the material, the support surface 13 of the printing table 3 is designed as a cohesive surface. Interruptions in the support surface 13 can be provided. However, it is advantageous if the printing table 13 forms a unit and thus the support surface 13 is also moved as a coherent unit.

As a further alternative, the holding device cannot be provided as a vacuum device 11. For example, the holding device can be provided by means of one or more grippers which grip the web material 1 and hold it on the support surface 13 of the printing table 3.

During the movement of the web material 1 on the printing table 3 past the print head shuttle 5, the print head shuttle 5 prints the web material 1 with a printing medium. For this purpose, the print head shuttle has one or more print heads 14. In the representation of the Fig. 2 the print head shuttle 5 has two print heads 14a, 14b. A printhead 14 can comprise a nozzle or a nozzle row with a plurality of juxtaposed nozzles. The pressure medium can be ejected in droplets through the nozzles. For example, one print head 14 can be used for each desired color or material to be applied.

The print heads 14 are selectively activated in order to selectively apply printing medium to the web material 1 and thus generate a desired print image on the web material. Here, the print head shuttle 5 moves back and forth transversely to the feed direction 4 of the web material 1, so that the print heads 14 move over the web material 1. The movement of the printing table 3 along the feed direction 4 thus results in a relative movement of the web material 1 to the print heads 14 in a first printing direction and the movement of the print head shuttle 5 transversely to the feed direction 4 causes a relative movement of the web material 1 to the print heads 14 in a second Provided printing direction which runs transversely to the first printing direction. By selectively controlling the movement of the printing table 3, the movement of the print head shuttle 5 and the ejection of the printing medium from the print heads 14, a desired print image is thus applied to the web material 1.

Depending on the web material 1 used and the printing medium used, it can be advantageous to bring the web material 1 to a certain temperature for printing. For this purpose, the printing table 3 according to FIG Fig. 2 a heater 15. By means of the heating device 15, the supporting surface 13 of the printing table 3 is brought to a predetermined temperature. As a result, the web material 1 arranged on the support surface 13 is heated to a printing temperature for printing.

The print head shuttle 5 also has a smoothing device. In the representations of the Figures 1 and 2 the smoothing device is a brush 16 which extends along a longitudinal direction which runs parallel to the feed direction 4. The brush 16 as a functional part of the smoothing device is thus elongated in the longitudinal direction, parallel to the feed direction. So it has a greater extent in the longitudinal direction than in other directions. The smoothing device can thus have a smoothing effect when moving across the web material 1 transversely to the feed direction 4. The brush 16 is as in FIG Fig. 2 shown, related arranged on the side of the print head shuttle 5 in the direction of movement of the print head shuttle 5. The brush 16 is movable up and down relative to the print head shuttle 5 between a first and a second position. In the first position, the brush 16 comes into contact with the support surface 13, so that when the pressure head shuttle 5 moves transversely to the feed direction 4, the brush 16 sweeps over the web material 1 arranged on the support surface 13 of the printing table 3. In the second position, the brush 16 is arranged above the printing table 3 in such a way that the brush 16 touches neither the printing table 3 nor the web material 1 when the printing head shuttle 5 moves.

During a printing process, while the printing table 3 is in the rear position, a connection between the web material 1 and the support surface 13 is formed by means of the vacuum device 11. According to the Fig. 2 Brush 16 arranged on the left side of the print head shuttle 5 is brought into the first position while the print head shuttle 5 is in a first position in which the print head shuttle 5 and the brush 16 are arranged to the right of the printing table 3. During a subsequent first movement of the print head shuttle 5 over the printing table 3 and the web material 1, the brush 16 brushes over the web material 1 and thus smooths wrinkles and / or bubbles in the web material 1 during the formation of the contact between the support surface 13 and the web material 1 and / or during the heating of the web material 1 by means of the heating device 15.
After the brush 16 has been moved over the entire width of the web material 1, the brush 16 is brought into the second position. During subsequent movements of the printing head shuttle 5, during the movement of the printing table 3 from the rear to the front position, the brush 16 does not come into contact with the web material 1. After the web material 1 has been released from the printing table 3 and the printing table 3 has moved from the front to the rear position, a connection is again established between the web material 1 and the support surface 13 and the brush 16 is moved into the first position. Thus, after each contact is made with the support surface 13 of the printing table 3, the web material is smoothed by the brush 16 during the first subsequent movement of the print head shuttle 5 over the web material 1.

The brush 16 has a length which corresponds at least to the length of the support surface 13 of the printing table 3. Here, as in the Fig. 1 It can be seen that the length of the brush 16 can be greater than a length of the print head shuttle 5, which can be shorter than the length of the support surface 13. This ensures that the web material 1 through the brush 16 is smoothed over the entire length on which contact with the support surface 13 of the printing table is made.

A capping station 17, which prevents the print heads 14 from drying out, can optionally be provided. When the printing device is not in use, the print head shuttle 5 is moved into a position in which the print heads 14 are shielded from the environment by the capping station 17 and thus the print heads 14 are prevented from drying out due to the evaporation of solvent in the printing medium. Furthermore, a pressure medium container 18 can optionally be provided for cleaning and / or preparing the print heads 14 for a printing process. The print head shuttle can be moved into a position in which the print heads 14 are located above the pressure medium container 18. Subsequently, pressure medium can be ejected from the print heads 14 into the pressure medium container 18 in order to free the print heads 14 of impurities and / or pressure medium residues and / or to remove air from transport paths of the pressure medium in the print heads 14.

Like in the Fig. 1 drying devices 19a, 19b are shown along the path of the web material 1 behind the printing table 3 and in the area of the second web tension measuring roller 7b and the second dancer 9b. The printing medium is dried on the web material 1 by means of the drying devices 19a, 19b. For example, the drying devices 19a, 19b can be hot air blowers and / or UV radiators. Different drying devices 19a, 19b can be provided.

The Fig. 3 shows further configuration options of a printing device. This can, for example, the printing device from the Fig. 1 be. Alternatively, the design options according to the Fig. 3 in a different printing device than the printing device according to FIG Fig. 1 be provided. A printed image testing device 20 is arranged along the path of movement of the web material 1 behind the second dancer 9b and the drying devices 19a, 19b. The printed image checking device 20 has an image recording device 21 which is set up to record an image of the printed image on the web material 1. In the print image checking device 20, the recorded image of the print image on the web material 1 is compared with comparison image data, which can be, for example, print job data of a print job for printing the print image. If, on the basis of the comparison of the print image on the web material 1 with the comparison image data, a match is found between the print image and the comparison image data, the print image is determined to be a correct print image. If based on the comparison of the If no correspondence is found between the print image and the comparison image data on the web material 1 with the comparison image data, the print image is determined to be an incorrect print image.

A correspondence between the print image and the comparison image data is established when the recorded image of the print image on the web material 1 corresponds to the comparison image data within predetermined limits. If the recorded image of the print image on the web material 1 does not correspond to the comparison image data within the predetermined limits, no correspondence is established between the print image and the comparison image data. The comparison of the recorded image with the comparison image data can be, for example, a pixel comparison and / or a comparison of characteristic values of the recorded image, for example a contrast value.

To support the movement of the web material 1, a roller drive 22 is arranged along the movement path of the web material 1 behind the testing device 21. A further dancer 9c for controlling the web tension of the web material 1 is arranged behind the roller drive 22. The further dancer 9c can, for example, be controlled by the control device 10 in accordance with the second sensor data. Alternatively, a further web tension measuring roller can be provided which generates third measurement data by means of which the control device 10 controls the further dancer 9c.

Arranged along the path of movement of the web material 1 behind the testing device 21 and the further dancer 9c is a finishing device 23 which is set up to make the web material 1 into individual sheets. For example, the web material 1 can be fed to the assembly device 23 and cut to a predetermined sheet size by means of a cutting device 24 of the assembly device 23 in order to assemble the web material 1 into individual sheets. The individual sheets are then directed in a document switch 25 onto different transport paths 26a, 26b. A transport path 26a leads into a document container 27. Another transport path 26b leads into a reject container 28. Sheets that carry a print image that has been determined to be the correct print image are designated as document sheets 29 and are routed from the document switch 25 to the transport path 26a, the leads into the document container 27. Sheets that carry a print image that has been determined to be an incorrect print image are designated as waste sheets 30 and are directed by the document switch 25 onto the transport path 26b, which leads into the reject bin 28. In this way a sorting out of printed sheets, which have errors in the print image. The print image of a waste sheet 30 can then be reprinted.

Optionally, a bad marking device 31 can be provided, which is arranged along the path of movement of the web material 1 behind the testing device 21 and in front of the assembly device 23. The bad marking device 31 is set up to provide a print image which has been determined as an incorrect print image with a marking which identifies the print image as an incorrect print image. For example, the bad marking device 31 can include a print head for this purpose.

It can be provided that the print image comprises several individual print images. In this case, each individual print image can be determined as a correct individual print image or incorrect individual print image and the bad marking device 31 can be set up to provide each individual print image determined as an incorrect individual print image with a marking, which identifies the individual print image as an incorrect individual print image. In this case, the document switch 25 can be omitted and all the separated sheets can be fed to the document container 27 via the transport path 26a. Alternatively, the document switch 25 can be provided and set up to transfer printed sheets with a print image that includes a number of individual print images identified as incorrect individual print images that exceeds a predetermined maximum number of incorrect individual print images via the transport path 26b To feed reject container 28 and to feed other sheets via transport path 26a to document container 27.

The Fig. 4 shows another printing device for printing on a printing substrate. In the embodiment according to Fig. 4 if the printing device has two dancers 9a, 9b, but no third dancer. In this design example, a roll unwind module 40 comprises the roll 2, the first web tension measuring roll 7a with the sensor device 8a, the first dancer 9a and the associated deflection rolls 6. According to the embodiment shown, a printing module 41 comprises the printing table 3, the print head shuttle 5 and the brush 16. A drying module 42 comprises the second web tension measuring roller 7b with the sensor device 8b, the second dancer 9b, the drying devices 19a, 19b and the associated deflection rollers 6. An image processing module 43 comprises the print image checking device with the image recording device 21 and optionally the bad marking device 31 Drying module 42 and the image processing module 43 can be combined to form a drying and image processing module. According to the Fig. 4 In the embodiment shown, a packaging module 44 includes the roller drive 22, the packaging device 23 with the cutting device 24, the document switch 25, the transport paths 26a, 26b, the document container 27 and the reject container 28.

The features disclosed in the above description, the claims and the drawing can be of importance both individually and in any combination for the implementation of the various designs.

Reference list

1

Railway material

2

role

3

Printing table

4th

Feed direction

5

Print head shuttle

6

Pulleys

7a, 7b

Web tension measuring roller

8a, 8b

Sensor device

9a, 9b, 9c

dancer

10

Control device

11

Vacuum device

12th

channels

13th

Contact surface

14a, 14b

Print heads

15

Heating device

16

brush

17th

Capping station

18th

Pressure medium tank

19a, 19b

Drying device

20th

Testing device

21st

Image capture device

22nd

Roller drive

23

Assembly device

24

Cutting device

25

Document switch

26a, 26b

Transport routes

27

Document tray

28

Reject bin

29

Document sheet

30th

Waste sheets

31

Bad marking device

40

Roll unwind module

41

Print module

42

Drying module

43

Image processing module

44

Assembly module

Claims (15)

Device for printing a print substrate (1), with - A printhead shuttle (5) with at least one printhead (14a, 14b), which is set up to apply a printing medium to a printing substrate (1) in order to generate a print image, the printing substrate (1) being a web material which, along a web path in a The feed direction (4) is displaceable, and the print head shuttle (5) is arranged on a first side of the print substrate (1); and - A printing table (3) with a support surface (13) which is arranged opposite the print head shuttle (5) on a second side of the printing substrate (1), wherein the printing table (3) comprises a holding device (11) which is set up to To hold the printing substrate (1) in such a way that a relative movement between the printing table (3) and the printing substrate (1) is prevented for printing;
wherein the print head shuttle (5) has a smoothing device (16) which is set up to come into contact with the support surface (13) of the printing table and to be moved over at least a part of the support surface (13) in such a way that it over a on the support surface (13) of the printing table (3) arranged printing substrate (1) strokes in order to smooth it. Device according to Claim 1, characterized in that the smoothing device (16) extends along a longitudinal direction which runs parallel to the feed direction (4). Device according to claim 1 or 2, characterized in that the smoothing device (16) is set up to be moved transversely, preferably perpendicularly to the feed direction (4) over the support surface (13) of the printing table (3). Device according to at least one of the preceding claims, characterized in that the smoothing device (16) is arranged on the print head shuttle (5) in such a way that the smoothing device (16) moves with the print head shuttle (5), the smoothing device (16) related on a direction of movement of the print head shuttle (5) is preferably arranged at the front of the print head shuttle (5). Device according to at least one of the preceding claims, characterized in that the smoothing device (16) is movable transversely to a direction of movement of the pressure head shuttle (5) between a first and a second position. Device according to claim 5, characterized in that the smoothing device (16) is in contact in the first position with the support surface (13) of the printing table (3), so that the smoothing device (16) when moving over the surface on the support surface (13 ) of the printing table (3) strokes the printing substrate (1), and that the smoothing device (16) in the second position is arranged above the printing table (3) that the smoothing device (16) does not touch the printing substrate (1) when it moves . Device according to at least one of the preceding claims, characterized in that the smoothing device (16) has a length which corresponds to at least one length of the support surface (13) of the printing table (3), the length of the smoothing device (16) preferably being the same or greater as a length of the printhead shuttle (5). Device according to at least one of the preceding claims, characterized in that the smoothing device comprises a brush (16). Device according to at least one of the preceding claims, characterized in that the web material (1) is a film material. Device according to at least one of the preceding claims, characterized in that the holding device (11) comprises a vacuum device which is set up to suck the printing substrate (1) onto the printing table (3) by means of a negative pressure in order to hold the printing substrate (1). Device according to at least one of the preceding claims, characterized by - A first web tension measuring device (7a, 8a) which is arranged along the web path in front of the printing table (3) and is set up to generate first measurement data which indicate a mechanical web tension of the printing substrate (1) on the first web tension measuring device (7a, 8a); - A first tensioning device (9a) which is arranged along the web path in front of the printing table (3) and is set up to set a mechanical web tension of the printing substrate (1); - A second web tension measuring device (7b, 8b) which is arranged along the web path after the printing table (3) and is set up to generate second measurement data which indicate a mechanical web tension of the printing substrate (1) on the second web tension measuring device (7b, 8b); - A second tensioning device (9b) which is arranged along the web path after the printing table (3) and is set up to set a mechanical web tension of the printing substrate (1); and - A control device (10) which is set up - To receive the first measurement data, to generate first control data based on the first measurement data and to control the first tensioning device (9a) in accordance with the first control data, in such a way that the first tensioning device (9a) applies a first predetermined web tension of the printing substrate (1) to the first tensioning device (9a) causes; and - To receive the second measurement data, to generate second control data based on the second measurement data and to control the second tensioning device (9b) in accordance with the second control data, in such a way that the second tensioning device (9b) applies a second predetermined web tension of the printing substrate (1) to the second tensioning device (9b) causes. Device according to Claim 11, characterized in that the control device (10) is set up to keep the web tension of the printing substrate (1) constant along the web path in front of the printing table (3) and the web tension of the printing substrate (1) along the web path during a printing process to keep constant behind the printing table (3). Device according to at least one of the preceding claims, characterized by a separation device comprising: - A test device (20) with an image recording device (21) which is set up - take an image of the print image on the web material (1), - to compare the recorded image of the print image on the web material (1) with comparison image data, - to determine the print image as a correct print image if, based on the comparison of the print image on the web material (1) with the comparison image data, a correspondence between the print image and the comparison image data is established, and - to determine the print image as an incorrect print image if, based on the comparison of the print image on the web material (1) with the comparison image data, no correspondence is found between the print image and the comparison image data; - a finishing device (23) which is set up to assemble the web material (1) into individual sheets; and - A document switch (25) which is set up to guide a made-up sheet onto one of a first transport path (26a) and a second transport path (26b), wherein - A made-up sheet with a print image, which has been determined as a correct print image, is directed onto the first transport path (26a) and - A made-up sheet with a print image, which was determined to be an incorrect print image, is directed onto the second transport path (26b). A method for printing on a printing substrate (1), comprising: - Application of a printing medium to a printing substrate (1), which is a web material (1) which is displaceable along a web path in a feed direction (4), by means of at least one print head (14a, 14b) of a print head shuttle (5) which is on a the first side of the print substrate (1) is arranged for generating a print image; - Holding the printing substrate (1) by means of a holding device (11) of a printing table (3) which is arranged opposite the print head shuttle (5) on a second side of the printing substrate (1) such that a relative movement between the printing table (3 ) and the printing substrate (1) is prevented; and - Smoothing of the printing substrate (1) arranged on a support surface (13) of the printing table (3) by means of a smoothing device (16) which brushes over the printing substrate (1) arranged on the supporting surface (13) of the printing table (3) by being with the support surface (13) of the printing table (3) comes into contact and is moved over at least part of the support surface (13). Method according to claim 14, characterized in that the smoothing device (16) is movable transversely to a direction of movement of the printhead shuttle (5) between a first and a second position, the smoothing device (16) in the first position with the support surface (13) of the Printing table (3) comes into contact, so that the smoothing device (16) strokes during a movement over the printing substrate (1) arranged on the support surface (13) of the printing table (3), and the smoothing device (16) in the second position so is arranged above the printing table (3) so that the smoothing device (16) does not touch the printing substrate (1) during a movement.

Images