DE102019132581A1 - WIDE SECTION REMOVAL AID FOR WIDE FORMAT ROLL PRINTER - Google Patents

Abstract

A roll printer (100) with an input roll (R1) for unwinding a web-shaped medium (8) to a support surface (111) for the medium, which is provided with suction holes and with a suction device (112) for sucking the medium (8) against the Support surface is connected; - a printhead arrangement (110), which is arranged on or above the support surface (111), for ejecting ink onto the medium (8); - an ink treatment station (150) for treating the ink ejected onto the medium in such a way, that the ink hardens on the medium (8); and a control device (6) which is configured to: - determine the occurrence of an error (E3, E4) which leads to the printing operation of the printer being terminated; - determine whether the error (E3, E4) is a wet ink error where wet ink is expected to be present on a portion of the web-shaped medium (8) to be removed; - if the error (E4) was recognized as a wet ink error, an error handling suction application signal (Ac4) for applying suction to transmit the medium (8) via the support surface (111).

Description

BACKGROUND OF THE INVENTION

Technical field

The invention relates to a roll printer with a printhead arrangement and an ink treatment station for curing the ink ejected by the printhead arrangement.

Description of the prior art

In roll printers, images are printed on a web-shaped medium that extends continuously from an input roll to an output location, such as an output roll. Ink is ejected from the printhead assembly onto the web medium and is then treated in the ink treatment station to cure the ink. An example of such an ink treatment station is a UV lamp which cures the ink by irradiation with UV light. Between jet printing and treatment, the ink is wet and easily transfers to anything that comes into contact with it. In practice, errors can occur in the roll printer that cause the roll printer to stop operating, including treating the ink, without being able to resume normal operation. A remnant of wet ink can then remain on a portion of the web medium. This section must be removed from the roll printer without contaminating the printer and / or the operator. In practice, the wet ink section is often separated from the rest of the web medium. Particularly when printing in wide format, where the width of the web-shaped medium can exceed 3 m, this removal of the web section by the operator is cumbersome, since the web-shaped medium can move uncontrollably during the cutting process under the influence of gravity. It is known in the prior art to provide clamping devices which grip the section to be removed on both sides of the web-shaped medium. However, such clamping devices add additional components to the roll printer, can deform the web-shaped medium during operation, and / or are not suitably positioned in certain situations in order to clamp the medium without coming into contact with the wet ink.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a simple and efficient means which reduces the risk of contamination when a web-shaped medium provided with wet ink is removed from a roll printer, in particular a wide format roll printer.

In a first aspect, the invention provides a roll printer according to claim 1.

• - eine Eingaberolle zum Abwickeln eines bahnförmigen Mediums auf eine Unterstützungsfläche für das Medium, die Sauglöcher aufweist und an eine Saugeinrichtung angeschlossen ist, damit das bahnförmige Medium gegen die Unterstützungsfläche angesaugt wird;
• - eine Druckkopfanordnung, die über der Unterstützungsfläche für das Medium positioniert ist, um Tinte auf das bahnförmige Medium auszustoßen;
• - eine Tintenbehandlungsstation zum Behandeln der auf das bahnförmige Medium ausgestoßenen Tinte derart, dass die Tinte auf dem bahnförmigen Medium aushärtet; und
• - eine Steuereinrichtung, die dazu konfiguriert ist:
  • - das Auftreten eines Fehlers festzustellen, der zu einem Anhalten des Druckbetriebs des Druckers führt;
  • - festzustellen, ob der Fehler ein Nasstinten-Fehler ist, der darauf hindeutet, dass nasse Tinte auf einem zu entfernenden Abschnitt des bahnförmigen Mediums vorhanden ist;
  • - wenn festgestellt wird, dass der Fehler ein Nasstinten-Fehler ist, ein Fehlerbehandlungs-Sogerzeugungssignal zu senden, um über die Unterstützungsfläche für das Medium einen Sog auf das bahnförmige Medium auszuüben.

This roll printer includes:

• an input roller for unwinding a web-shaped medium onto a support surface for the medium, which has suction holes and is connected to a suction device, so that the web-shaped medium is sucked against the support surface;
• a printhead assembly positioned over the media support surface to eject ink onto the web-shaped medium;
• an ink treatment station for treating the ink ejected on the web medium in such a way that the ink hardens on the web medium; and
• a control device configured to:
  • - determine the occurrence of an error which leads to the printing operation of the printer being stopped;
  • determine whether the error is a wet ink error, which indicates that there is wet ink on a portion of the web media to be removed;
  • if it is determined that the error is a wet ink error, send an error handling suction generation signal to apply suction to the web-shaped medium via the support surface for the medium.

Due to the time lag between jet printing and ink treatment, wet ink may remain on the web medium when printing is stopped due to a detected error. The controller determines whether such an error occurs and controls the printhead assembly and ink treatment station to stop printing or processing the image on the web medium. The controller then determines whether there is a risk of wet ink on the web medium after the error has occurred. This can be done, for example, by checking whether or not the printhead assembly printed within a predetermined period of time before the error occurred (or before the printing operation actually stopped) or, in a more basic example, by checking whether at the time of the error a print job was being processed on the roll printer. If there is a risk of a residue of wet ink on the web-like medium is present, the controller classifies the error as a wet ink error and continues to issue an error handling suction signal. The error handling suction application signal is intended to apply suction to the web-shaped medium via suction holes in the support surface on which the section of the web-shaped medium with the remnants of wet ink is located after the fault has occurred. This suction ensures that the section of the medium remains in place during the operations to remove this section. The operator can then proceed to cut the portion of the web-like medium free without the risk of the web-like medium slipping off the support surface and contaminating the roll printer. In this way, the invention provides a simple and inexpensive solution for removing portions of the web-shaped medium with wet ink in front of a roll printer. The object of the invention is thus achieved.

More specific optional features of the invention are given in the dependent claims.

• - die Saugeinrichtung zum Anlegen des Saugdruckes an das bahnförmige Medium über die Unterstützungsfläche für das Medium; oder
• - eine Benutzerschnittstelle zur Anzeige eines Hinweises auf die Fehlerbehandlungs-Sogausübung.

In one embodiment, the error handling pull signal is configured to control:

• - The suction device for applying the suction pressure to the web-shaped medium on the support surface for the medium; or
• - A user interface for displaying an indication of error handling suction.

Roll printers, as they are known so far, are generally configured to switch off the suction pressure when the printing operation is stopped when a sufficiently critical error has been detected. In a preferred embodiment, the control device transmits the error handling suction signal to the suction device, which then subsequently applies the negative pressure to the web-shaped medium via the holes in the support surface. The suction already applied may be maintained, or the suction device may be reactivated after a limited period without suction or reconnected to the support surface for the medium in order to apply negative pressure to the medium. In an alternative embodiment, it can be preferred for specific error situations that the operator controls the suction device in order to apply suction to the web-shaped medium after the error has occurred. In that case, the control device is configured to stop the suction device or to disconnect it from the support surface for the medium when the fault has been detected and then to indicate to the operator that the suction device has to be reactivated or reconnected. For this purpose, the user interface displays a request to the operator after receiving the error handling suction exercise signal, which prompts him or her to control the suction device. The request can e.g. a visualized instruction on the screen, e.g. in text form or in symbolic form. Preferably, this latter instruction is part of a series of error handling instructions that indicate to the operator the various steps to be taken to correct the specific error that occurred.

In another embodiment, the roll printer according to the invention further comprises a scanning ink jet printhead assembly which is movable over the media support surface, and wherein the ink treatment station is a curing station or a drying station positioned downstream of the ink jet printhead assembly. The scanning ink jet printhead assembly includes a carriage that supports the printheads and is movable along a portal that extends laterally across the media support surface. A scanning roll printer is preferred for wide format applications because it requires a relatively small number of printheads compared to the width of the media support area. The ink treatment station in this embodiment is an active treatment station that directs radiation onto the medium to cure the ink thereon. The radiation can be UV or infrared radiation.

Additionally or alternatively, heat can be applied to cure the ink, e.g. by heating the support surface for the medium at the ink treatment station, or by means of nozzles for heated air, which blow air onto the medium. Active treatment allows the ink to dry quickly, which results in quick processing and also a compact roll printer.

In a preferred embodiment, the curing station comprises UV lamps for curing the ink on the web-shaped medium with UV radiation. The printheads in this embodiment are connected to a source of UV-curable ink so that the printheads eject droplets of UV-curable ink during operation. After ejection, the UV radiation from the UV lamps cures the wet ink so that the ink hardens. In their wet state, some UV curable inks are classified as dangerous. Furthermore, UV inks generally require UV radiation for curing. The invention is particularly advantageous for such UV-curable inks since it presents the dangers both for the roll printer and for the operator reduced. The UV lamps can be, for example, LEDs or lamps emitting UV radiation.

In one embodiment, the control device has a memory that stores an error catalog in which at least one error is provided with an identifier for wet ink errors, and wherein the control device is configured to transmit the error handling suction signal when the detected error with the identifier for wet ink defects. The error catalog can include a table or list that links each error to one or more identifiers. The fault catalog preferably contains a fault name or information for each fault that can be displayed on the user interface to inform the operator of the current fault. An error input identifier can be provided so that the control device can determine on the basis of input information from one or more components of the roll printer which error has occurred in the catalog. The error catalog can contain control commands for each error, which specify specific actions to be carried out by the control device if an error occurs. Errors in the catalog can still be grouped by type by assigning an error type label to each error. According to the invention, a specific group of errors is labeled in the error catalog with a wet ink error identifier. The control device can e.g. based on a wet ink error detection associated with the detected error, decide that the detected error is a wet ink error, or may derive from the received error information that the error is a wet ink error based on predetermined criteria stored in the error catalog (e.g. if a paper jam is detected while determining that the printheads are active). The identification of the errors via the error catalog represents a workload for the operator and enables an efficient handling of errors.

In another embodiment, the error catalog stores a plurality of errors that are not associated with the wet ink error detection, the controller being configured to prevent the suction device from applying suction to the media support surface when the detected error occurs Is the majority of the errors that are not related to the wet ink error detection. The error catalog also contains one or more non-critical errors (e.g. low ink levels, print artifacts detected) that do not require manual removal of a web-shaped medium with uncured ink. When such an uncritical error has been detected, printing operations can be resumed, either without interruption or after operator intervention. Any wet ink that is present at the time of an uncritical error can still be transported or cured by the roll printer.

In one embodiment, the controller is further configured to drive a user interface to display an indication of manual removal of the media to notify an operator that manual removal of a portion of the media is required to correct the detected wet ink error. If the control device detects a wet ink error, it drives the user interface to inform the operator of this error, e.g. by specifying the error type or name. To further assist the operator, the user interface provides instructions regarding operator actions required to correct the detected fault. These instructions can take the form of audio or video prompts that describe various actions that the operator must take. In this way, the operator can immediately start correcting the error without e.g. consult a manual first.

In another embodiment, the reference to manual removal of the medium includes cutting instructions for cutting the web-shaped medium upstream and downstream of the support surface for the medium. The portion of the media web with the remaining wet ink must be manually removed from the support surface. To do this, the user interface prompts the operator to cut this part by hand and separate it from the rest of the media web. Since the control device ensures that the part of the media web is held in position by suction, the operator is free to cut out the part in question without the risk of contamination of the roll printer.

• - den Rollendrucker in einem Fehlermodus zu betreiben, wenn der Fehler festgestellt worden ist; und
• - während sie sich in dem Fehlermodus befindet und nach der Übermittlung des Nassfehler-Sogausübungssignals die Saugeinrichtung dazu anzusteuern, als Reaktion auf ein Fehlersog-Abschaltsignal den Sog an der Unterstützungsfläche für das Medium abzuschalten.

In a further embodiment, the control device is configured to:

• - operate the roll printer in a fault mode when the fault has been determined; and
• - While it is in the error mode and after the transmission of the wet error suction exercise signal, the suction device is triggered to switch off the suction on the support surface for the medium in response to an error suction shutdown signal.

When a sufficiently critical error has been received, the controller operates the roll printer in the error mode, which involves transporting the media web and printing be stopped. If it is determined that the error is a wet ink error, the suction device applies the suction to the support surface for the medium in the failure mode after the wet error suction exercise signal is transmitted. In this situation, the controller is configured to maintain suction until an error handling suction shutdown signal is received from the user interface. The web-shaped medium is thus secured during the cutting operations. After the part of the media web has been cut out, the suction is switched off so that this part can be removed. Preferably, the user interface provides instructions and error handling suction cutout control means.

In a preferred embodiment, the roll printer is a roll-to-roll printer, which further has an output roll for rewinding the web-shaped medium and in which the support surface for the medium is essentially free of clamping devices for the media web. The media web is pulled from the input roll and transported to be rewound on the output roll. The media path extends continuously between the rolls. Pinching the media web at any point along its transport path is undesirable because it can deform or damage the medium.

• 1A eine schematische perspektivische Ansicht eines Drucksystems;
• 1b eine schematische perspektivische Ansicht einer Tintenstrahl-Druckkopfanordnung in dem Drucksystem nach 1A;
• 2 eine schematische perspektivische Ansicht einer Ausführungsform eines Drucksystems gemäß der Erfindung;
• 3 eine schematische Darstellung einer Ausführungsform eines Fehlerkataloges, der in einem Speicher einer Steuereinrichtung eines Rollendruckers gemäß der Erfindung gespeichert ist; und
• 4 ein schematisches Flussdiagramm der Arbeitsabläufe in einer Steuereinrichtung eines Rollendruckers gemäß der Erfindung.

Exemplary embodiments are now described with reference to the drawing, in which:

• 1A a schematic perspective view of a printing system;
• 1b is a schematic perspective view of an ink jet print head assembly in the printing system 1A ;
• 2nd is a schematic perspective view of an embodiment of a printing system according to the invention;
• 3rd is a schematic representation of an embodiment of an error catalog, which is stored in a memory of a control device of a roll printer according to the invention; and
• 4th a schematic flow diagram of the work processes in a control device of a roll printer according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the accompanying drawings, in which all the same reference numerals are used to identify the same or similar elements.

Printing system

1A shows an image forming apparatus 1 using a wide format inkjet printer. The imaging device 1 has a housing 2nd to accommodate a printing arrangement 10th on. The imaging device 1 also has at least one media input unit 3rd to hold one or more media 8th , 9 in the form of a media web wound into a roll. The media each have a role R1 , R2 fed. The roles are stored on respective role carriers. A transport route extends from the media input unit 3rd on the print assembly 10th over to a receiving unit 4th to hold the medium 8th , 9 after printing. A storage unit 19th for marking material is intended to accommodate marking materials. Any marking material for use in the printing assembly 10th is stored in one of several containers that are in fluid communication with respective printheads to supply the marking material to the printheads and an image on the medium 8th , 9 to print. The receiving unit 4th can use a take-up roll to wind up the printed media 8th , 9 or a reception tray for holding sheets of the printed medium 8th , 9 exhibit. Optionally, the receiving unit 4th Processing means for processing the medium 8th , 9 after printing, for example a post-treatment device such as a coater, a folding device or a punch. The imaging device 1 for wide format also has a user interface 5 for receiving print jobs and optionally for manipulating the print jobs. The local user interface 5 is integrated in the printing device and can have a display unit and an operating panel. Alternatively, the control panel can be integrated in the display unit, for example in the form of a touch-sensitive screen as an control panel. The local user interface 5 is with a control device 6 connected to the imaging device 1 connected is. The control device 6 , for example a computer, contains a processor which is designed to issue commands to the image forming device, for example to control the printing process. The imaging device 1 can optionally be connected to a network. The connection to the network is schematic in the form of a cable 7 shown, but it could also be a wireless connection.

The imaging device 1 can receive print jobs over the network. Furthermore, the control device 6 of the imaging device 1 optionally be equipped with a USB port so that print jobs can be sent to the imaging device via the USB port 1 can be transmitted.

Printing arrangement

1B shows the printing arrangement 10th , which is an ink jet printing arrangement. The printing arrangement 10th has a support area to support the medium 8th , 9 while printing on. The support area in 1B is on a roller 11 formed in the form of a drum which is rotatable in a sub-scanning direction A, however, could optionally also be a flat support surface. The support surface preferably has suction holes for at least temporarily holding the medium 8th , 9 in a fixed position with respect to the support area. The printing arrangement 10th has printheads 12a , 12b on that on a scanning carriage 13 are arranged or alternatively form a stationary page-wide array. The scanning car 13 is on suitable tours 14 , 15 guided so that it can move back and forth in a main scanning direction B. Any printhead 12a-12b has a nozzle surface 16 in which there is at least one nozzle 17th located. The printheads 12a-12b are configured to place droplets of the marking material on the medium 8th , 9 to eject. The support area, the car 13 and the printheads 12a-12b are each by a suitable control device 6a , 6b between 6c controlled.

The medium 8th , 9 is fed in the form of a web and can be formed, for example, from paper, cardboard, label material, coated paper, plastic or textile material. The medium 8th , 9 is through the roller 11 in the sub-scanning direction A on the four printheads 12a-12b moved past that contain a liquid marking material.

The scanning car 13 carries the four printheads 12a-12d and can be reciprocated in the main scanning direction B parallel to the support surface for the medium so that the medium 8th , 9 can be scanned in the main scanning direction B. Any number of printheads can be used. Preferably on the cart 13 at least one printhead 12a-12d arranged according to the color of the marking material, for example one of the four print heads 12a , 12d for each of the colors used, usually black, cyan, magenta and yellow. In a full color printer, black marking material is mostly used more often than the other colored marking materials. Therefore, on the cart 13 there are more printheads that contain black marking material than printheads with marking materials in the other colors. Alternatively, the printhead containing black marking material could be larger than any of the printheads containing marking material in a different color.

The car 13 is on the guides 14 , 15 guided, which have the shape of guide rails or guide rods, as in 1B is shown. The car 13 can be along the guides by a suitable drive (not shown) 14 , 15 are driven. An alternative is the medium 8th , 9 to move in the main scanning direction B.

Printheads

Any printhead 12a-12d has a nozzle surface 16 with at least one nozzle 17th that is in fluid communication with a pressure chamber containing a liquid marking material contained in the printhead 12a-12d is kept ready. In the nozzle area 16 is a number of nozzles in the example shown 17th arranged in a single straight column parallel to the sub-scanning direction. In 1B are eight nozzles 17th shown per printhead, but of course in a practical embodiment at least a few hundred nozzles 17th be provided per print head, optionally also arranged in several columns. As in 1B are shown are the respective printheads 12a-12d arranged parallel to each other so that the corresponding nozzles 17th of the respective print heads are aligned in one line in the main scanning direction B. This means that a line of pixels in the main scanning direction B can be formed by selectively up to four nozzles 17th be activated, each to a different one of the printheads 12a-12d heard. This parallel arrangement of the printheads 12a-12d with appropriate line alignment of the nozzles 17th is advantageous to increase productivity and / or to improve print quality. Alternatively, multiple printheads can be placed adjacent to each other on the carriage 13 be arranged that their nozzles 17th are not aligned in lines, but are staggered. For example, this measure can be taken to increase the print resolution or to increase the effective printing area that can be processed in a single scanning movement in the main scanning direction.

The pixels are created by ejecting droplets of the marking material from the nozzles 17th .

When ejecting marking material, some marking material can be lost and on the nozzle surface 16 of the printhead remain. The one on the nozzle surface 16 Existing ink can cause droplets to be ejected and these droplets to be positioned on the media 8th , 9 adversely affect. Therefore, it may be beneficial to remove excess ink from the nozzle surface 16 to remove. The excess ink can be removed, for example, by wiping with a wiper and / or by using an appropriate one Non-wetting property of the surface, e.g. through a coating.

Curing the ink

In the in 2nd The preferred embodiment shown are printheads of a printhead arrangement 110 configured to eject UV curable ink. Each printhead is connected to a source of UV curable ink. UV-curable ink offers a wide range of colors and the possibility to control the gloss, which makes these inks particularly interesting for graphic applications. As the name suggests, UV curable inks (or UV inks for short) require curing by UV radiation to get the liquid ink after it has been transferred from the printheads to the medium 8th ejected, harden or solidify. Therefore, it is downstream of the printhead assembly 110 a curing station 150 arranged. The curing station 150 can, in one example, be on the same carriage as the printhead assembly 110 be mounted and / or be a separate unit in the direction of transport of the medium 8th at a distance from the printhead assembly 110 is arranged. The curing station 150 contains UV lamps such as UV lamps, preferably LEDs. The UV radiation solidifies or hardens the wet UV ink and thus makes the printed web suitable for further handling by an operator or handling devices for the media.

Rail transport system

2nd shows a roll printer 100 according to the invention. It is understood that any features of the imaging device 1 to 1A also with the roll printer 100 to 2nd can be realized. The roll printer 100 is a roll-to-roll printer where the media 8th from a first media roll on the input roll R1 on a second media roll on an output roll R3 is rewound. The medium 8th is in a substantially horizontal direction from the input roller R1 deducted and a first dancer 131 fed. The first dancer 131 is a roller that is rotatable about its axis and movable in a substantially vertical direction V. Preferably the dancer 131 controlled so that while the medium 8th from the input role R31 subtracted, the vertical position of the dancer is adjusted so that the medium 8th the input role R1 leaves essentially in the horizontal direction, regardless of the amount of medium that is still on the input roller R1 is available. This position setting can be done by using a roller drive to drive the input roller R1 a suitable force is built up. The first dancer 131 is in operation according to the decreasing diameter of the media roll on the input roller R1 set the media path between the input roll R1 and the first dancer 131 keep horizontal. The medium 8th then writhes around the first dancer 131 in the substantially vertical direction V to a deflecting element 153 . The medium thus becomes the first dancer 131 curved at a substantially right angle (ie about 90 °). By adjusting the vertical position of the first dancer 131 this angle is kept constant while the diameter of the media roll on the input roller R1 decreases. Maintaining a substantially right angle enables decoupling of forces on the medium on the side of the first dancer to the side of the input roller 31 act from forces on the medium 8th on the side of the first dancer closer to the print head arrangement 131 Act. This increases the accuracy of the gradual feed of the media web and the positional stability between the feed steps. Preferably the first dancer 131 positioned so that the medium 8th essentially horizontally between the input roller R1 and the first dancer 131 extends. The weight of wide media rolls (e.g. several meters wide) causes the middle part of the input roll to sag R1 . Because of this sagging is the input roll R1 in practice not perfectly straight, but has a parabolic curvature with the lowest point in the middle of the input roller (when the media roll is positioned centrally on the input roller). The media roll is not completely cylindrical symmetrical during unwinding, which leads to an inaccuracy in the positioning of the media web. By moving the media path in a substantially horizontal direction from the top of the media roll to the first dancer 131 the effect of sagging is eliminated or significantly reduced. The medium 8th between the input role R1 and the first dancer 31 has an essentially homogeneous tension both in the longitudinal direction and in the width direction of the web. This improves the accuracy of the positioning of the medium.

The deflecting element 153 curves the media web from its vertical orientation to an essentially horizontal printing surface 111 , which forms a support surface for the medium. The deflecting element 153 is preferably a stationary turning bar that has a low friction surface so that the media web slides over that surface with minimal resistance. The printing surface 111 has suction holes (not shown) through which a vacuum is applied to the media web so that it is on the printing surface 111 is liable. The vacuum is created by a suction device 112 generated with the holes in the printing surface 111 is in fluid communication. This ensures the flatness of the medium on the printing surface 111 improved. Above the printing surface 111 is the (inkjet) printhead assembly 110 . As before with reference to 1B has been described has the printing arrangement 10th (and also the printhead arrangement 110 ) a carriage that can be moved in the width direction over the media web, in order to strip an image onto the medium 8th to print.

Downstream of the printing surface 111 is a step roller 151 arranged. The step roller 151 , for example a drive roller, has a high friction surface (such as a rubber surface) for contact with the medium 8th . The step roller 151 is driven by a drive (not shown) configured to drive the step roller 151 to rotate a predetermined angle around the medium 8th over a predetermined distance across the printing surface 111 to move. The low friction of the stationary deflection element 153 in combination with the force decoupling through the 90 ° deflection with the help of the first dancer 131 improves the accuracy with which the medium 8th can be moved gradually. The rotation of the step roller 151 determines the feed of the medium 8th on the printing surface 111 . For illustration purposes, the elasticity or rigidity is by a symbolic spring 8A made visible. The rotation of the step roller 151 affects the tension in the web upstream of the step roller 151 . To make the web precise in relation to the printhead arrangement 110 transport, precise control of the web tension is required. It is also noted that the stiffness (spring 8A) can vary considerably between different media types such as paper, film, textile, etc.

Downstream of the step roller 151 the medium bends 8th a second dancer 141 . The second dancer is movable in a substantially horizontal direction. From the second dancer 141 the media path extends to the output roll R3 which winds the media web into a media roll.

The first and second dancers 131 , 141 are trained to put local tension on the media web. The first dancer 131 clamps the medium between the input roller R1 and the deflecting element 153 . The second dancer 141 clamps the medium between the step roller 151 and the output role R3 . Every dancer 131 , 141 is in an associated dancer hanger 130 , 140 held. Both dancers 131 , 141 are via a pull cable 133 , 143 with a respective actuator 135B , 145B connected. A spring element 137 , 147 is along the pull cord 133 , 143 intended. An engine or the actuator 135B , 145B exercises over the respective spring element 137 , 147 a move on the dancer in question 131 , 141 out. The spring element 137 , 147 exerts a pulling force on the respective dancer when it is stationary 131 , 141 out even if the dancer 131 , 141 is stationary. So can the tension of the medium 8th be set to an appropriate value.

The roll printer preferably contains 100 a position sensor (not shown) for determining the position of each dancer 131 , 141 . The position sensor can be an encoder, which is in a respective idler 135A , 145A is arranged because the rotation of the idler 135a , 145A a measure of the dancer's movement 131 , 141 delivers. The movement of every dancer 131 , 141 is preferably limited to a linear movement. In an advantageous embodiment, the dancers 131 , 141 hung at both ends by a rod. The linkage is an exemplary embodiment of a four-linkage in which the dancer 131 , 141 mounted on a middle one of the four poles. While the two outer rods are preferably straight, the middle rod preferably has such a curvature that the dancer 131 , 141 is limited to a substantially linear (rectilinear) movement.

The linkage provides a low friction solution to limit the dancer's movement 131 , 141 In addition, contact sensors 139 , 149 be provided for interaction with the position sensor. The contact sensors 139 , 149 represent a fixed position in relation to the frame of the printing system 100 and transmit a signal when the dancer 131 , 141 is in this position. By measuring the movement from this position, for example with the help of the encoder, the position of the dancer can be determined 131 , 141 can be determined quickly and precisely after a new media web has been threaded into the roll printer.

Furthermore, one or more spring sensors 138 , 148 be provided, which are configured to determine the force exerted by the spring element 137 , 147 is exercised. The spring sensor preferably has 138 , 148 an arrangement of individual detectors, which are positioned so that they the spring element 137 , 147 detect in different positions in its longitudinal direction. The spring force of the spring element 137 , 147 is determined by the spring constant and the spring length (especially by the spring extension). The length of the spring element 137 , 147 as with the help of the spring sensors 138 , 148 is thus determined, provides a precise measure of the spring force, which in turn is the tension of the medium 8th certainly.

In the in 2nd The embodiment shown are separate actuators 135B and spring elements 137 for controlling the spring force on each side of the dancer 131 intended. So different forces can be applied to the opposite ends of the dancer 131 be exercised. This enables dancer suspension 130 , 140 To compensate for tension deviations in the width direction of the media web.

This in 2nd The web transport system shown has the advantage that it avoids jamming of the media web, which would deform or damage the medium locally, which could lead to printing artifacts.

Error handling

4th shows schematically the steps of an embodiment of a method according to the invention for operating the printing system 100 . Before the printing operations begin, the web-shaped medium 8th from the input role R1 with the dispenser roll R3 connected. A print job, which comprises one or more images, is carried out in step a) by the control unit 6 received, after which printing starts (b). The images are in successive strips using the scanning printhead arrangement 110 on the medium 8th printed. Between the strips, the medium is passed through the step roller 151 stepped forward in its transport direction. The control unit controls during printing and transport 6 the suction device 112 so that over the printing surface 111 , which forms a support surface for the medium, a negative pressure is exerted on the medium (c).

This will cause the medium to hit the print surface 111 drawn.

The control unit monitors during operation 6 the occurrence of errors (d). Errors can be received by any of the printer assemblies, such as the transport system or printhead assembly. If there are no errors, the printer sets 100 its operation continues (step m)). If by the control unit 6 in step d) an error is detected, the control unit determines the type of error (e). The control unit points to this 6 a memory that contains an error catalog (EC in 3rd ) or a table that stores a list of errors E1-E4 and their associated characteristics. The EC error catalog lists every error E1-E4 as well as one or more determining factors for each error. Fault-determining factors In1-In4 may include input signal characteristics that the controller 6 allow the error E1-E4 identify or classify (f). In a basic example, the error catalog can contain EC for each error E1-E4 an input signal characteristic or identifier is stored, and a received signal can be matched with this input signal characteristic to the error E1-E4 to determine. The error catalog EC can then provide further characteristics for the error identified in this way, such as a character string or identifier T1-T4 which forms a name of the error through the user interface 5 is to be displayed, or control commands Ac1-Ac4 to trigger suitable actions to remedy the relevant error.

Several errors can share a common identifier in the error catalog EC. The mistakes E1-E4 can be grouped into specific error classes or error groups. For example, certain mistakes E1-E2 with an identifier T1 are reported as non-critical errors where the printing operation can continue (m) but the control unit 6 causes an error message Ac1, Ac2 to the user interface 5 to transmit. Critical mistakes such as the mistakes E3 , E4 with the identifiers T2 , T3 cause the control unit 6 stops printing (h). The web transport and the printing operation of the print heads are stopped. The critical errors may include media jam, excessive lateral positional deviation of the media path, or other operational issues that the printer itself cannot correct. If a critical mistake E3 or E4 occurs and printing stops suddenly, there may be uncured ink on the media 8th remain, for example on printed parts of the media web that are not yet the curing station 150 have been reached or have not yet been sufficiently exposed to UV radiation to fully cure. UV-curable inks generally do not simply cure in air, so care must be taken to remove the uncured ink from the printer without the wet ink contaminating the printer and / or operators. Certain types of uncured UV-curable inks are also classified as dangerous, so they should be handled with special care.

If at the moment the printing operation by the control unit 6 was stopped (error E3 with error type T2 ), there is no danger that there is damp ink on the medium, the control unit moves 6 with step k) and switches the suction on the printing surface 111 off, for example by switching off the suction device 112 or by controlling a valve to the suction device 112 from the printing surface 111 to separate.

The control unit 6 may be the presence of uncured ink from the activity status of the printhead assembly 110 deduce. If the printheads at the moment when the critical error E4 , T3 and if printing is stopped and ink is ejected, there is likely to be residual damp ink on the media path. The control unit 6 then continues to decide that the mistake E4 is a wet ink error (identifier X). The control unit 6 then proceeds to step i), in which the control unit transmits an error handling suction signal Ac4. As in 3rd is shown, the wet ink error can be identified using the special identifier X.

In a preferred embodiment, the control unit generates 6 the error handling suction signal Ac4 to move across the printing surface 111 a suction on the web-shaped medium 8th to be exercised after the wet ink error has been identified with the identifier X and the printing operation has been canceled. For environmental reasons, the control unit can then initially use the suction device 112 switch it off and reactivate it later, for example after a predetermined time or when an operator is present on the user interface 5 has been detected (j). When the operator at the printer 100 is present, on which the wet ink error occurred, is thus on the suction surface 111 the suction applied to the medium. This will place the medium on the print surface 111 held and fixed. Via the user interface 5 the operator is instructed by visual prompts, the web-shaped medium 8th on both sides of the printing surface 111 cut through. Because the part of the medium with the wet ink through the suction on the printing surface 111 remains fixed, there is no danger that this part will move uncontrolled and contaminate the printer. After the cut part on the printing surface 111 stabilized, for example by folding a leading end section and a trailing end section of the web on the parts with the damp ink, the suction can be switched off (k) and the cut-out part of the medium can be removed (1). For this purpose the user interface shows 5 a suction shutdown button after the media cutout prompts are complete. This enables the operator to easily remove the part of the web with the remaining uncured ink and without the risk of contamination.

In an alternative embodiment, the error handling pull signal can be through the user interface 5 be transmitted to the operator. Instead of the suction device 112 To control directly, an operating element is displayed or provided on the user interface, for example a button to induce the operator, the suction device 112 to activate. For example, if a wet ink error is detected, the control unit can operate the printer including the suction device 112 set and on the user interface 5 display an error message identifying the error as a wet ink error and an instruction to the suction device 112 to be activated before proceeding with the cut and remove web section operations discussed above.

It is to be understood that the disclosed embodiments are illustrative of the invention, which may be embodied in various forms. Special structural and functional details should not be interpreted as restrictive, but merely as a basis for the claims and as a guide for the person skilled in the art to carry out the invention variably in practically any suitable concrete configuration. In particular, the features shown and described in separate dependent claims can be used in combination, and any advantageous combination of such claims is hereby disclosed.

It is also understood that in this document the terms "includes", "comprehensive", "contains", "containing", "includes", "including", "has", "exhibiting", "has" and any variations thereof should be understood as inclusive (ie not exclusive) so that the process, procedure, facility, device or system to which they refer should not be limited to those features or parts or elements or steps that are expressly mentioned but may also include other elements, features, parts or steps that are not expressly listed or that belong to such a process, procedure, article or device. In addition, the terms "a" and "one", when used here, should be understood in the sense of "one or more" unless otherwise stated. In addition, the terms "first", "second", "third" etc. are only used as a distinctive aid and are not intended to impose any numerical requirements or to establish a certain order of importance for the objects.

Having described the invention herewith, it is obvious that this invention can be modified in many ways. Such modifications are not intended to be considered outside the spirit and scope of the invention, and all such modifications that are obvious to those skilled in the art are intended to be included within the scope of the following claims.

Claims (10)

A roll printer (100) with - an input roll (R1) for unwinding a web-shaped medium (8) to a support surface (111) for the medium, which are provided with suction holes and with a suction device (112) for sucking the medium (8) against the Support area is connected; - a printhead assembly (110) located on or above the support surface (111) for ejecting ink onto the medium (8); - an ink treatment station (150) for treating the ink ejected on the medium in such a way that the ink cures on the medium (8); and - a control device (6) which is configured to: - determine the occurrence of an error (E3, E4) which leads to the printing operation of the printer being terminated; - Determine whether the error (E3, E4) is a wet ink error, in which it is expected that wet ink is present on a part of the web-shaped medium (8) to be removed; - If the error (E4) was recognized as a wet ink error, transmit an error handling suction exercise signal (Ac4) for exerting suction on the medium (8) via the support surface (111). The roll printer (100) after Claim 1 , in which the error handling suction exercise signal (Ac4) is configured to control the following: - the suction device (112) for applying suction to the web-shaped medium via the support surface (111); or - a user interface (5) for displaying an error handling suction exercise request to an operator. The roll printer (100) after Claim 1 or 2nd wherein the printhead assembly (110) is a scanning ink jet printhead assembly that is movable over the support surface (111) and the ink treatment station (150) is a curing or drying station located downstream of the printhead assembly (110). The roll printer (100) after Claim 3 , in which the curing station (150) has UV steel for curing the ink on the medium by UV radiation. The roll printer (100) according to one of the preceding claims, in which the control device (6) has a memory for storing a media catalog (EC) in which at least one error (E4) has a wet ink error identifier (X) and in which the control unit (6) is configured to transmit the error handling suction exercise signal (Ac4) when the detected error (E4) has the wet ink error detection (X). The roll printer (100) after Claim 5 wherein the defect catalog (EC) continues to store multiple defects (E1-E3) that do not have wet ink defect detection, the controller being configured to prevent the suction device (112) from pulling on the support surface when the detected error is one of those errors that did not have wet ink error detection. The roll printer (100) of any of the preceding claims, wherein the controller (6) is further configured to control a user interface (5) to display a manual media removal notice to notify an operator that manual removal of a Part of the media (8) is required to correct the detected wet ink error. The roll printer (100) after Claim 7 wherein the manual media removal notice further includes cutting instructions for cutting the media upstream and downstream of the support surface (111). The roll printer (100) according to one of the preceding claims, wherein the control device (6) is configured to: - to operate the roll printer (100) in a fault mode when the fault (E1-E4) has been determined; and - Activate the suction device (112) to end the suction on the support surface for the medium in the error mode and after transmission of the error handling suction exercise signal (Ac4) in response to an error handling suction shutdown signal. The roll printer (100) according to any preceding claim, wherein the roll printer is a roll-to-roll printer, further comprising an output roll (R3) for rewinding the medium (8), and wherein the support surface (111) for the Medium is essentially free of clamping devices for the medium.

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