EP4603290A1 - A method for loading print media while tandem printing on a printer - Google Patents

A method for loading print media while tandem printing on a printer

Info

Publication number
EP4603290A1
EP4603290A1 EP24164670.2A EP24164670A EP4603290A1 EP 4603290 A1 EP4603290 A1 EP 4603290A1 EP 24164670 A EP24164670 A EP 24164670A EP 4603290 A1 EP4603290 A1 EP 4603290A1
Authority
EP
European Patent Office
Prior art keywords
print
vacuum zone
media
printer
medium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24164670.2A
Other languages
German (de)
French (fr)
Inventor
Eduardus J.W. Van Vliembergen
Martinus G.M. LANGE
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP4603290A1 publication Critical patent/EP4603290A1/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/0085—Using suction for maintaining printing material flat
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/007—Conveyor belts or like feeding devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J15/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in continuous form, e.g. webs
    • B41J15/04—Supporting, feeding, or guiding devices; Mountings for web rolls or spindles
    • B41J15/048—Conveyor belts or like feeding devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J15/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in continuous form, e.g. webs
    • B41J15/18—Multiple web-feeding apparatus
    • B41J15/22—Multiple web-feeding apparatus for feeding webs in separate paths during printing

Definitions

  • the present invention relates to a method for loading a print medium for tandem printing on a printer suited for tandem printing, to such a printer, and to a software product for performing the method on the printer.
  • Such a printer may comprise a transport device comprising an endless transport belt supported on at least one pair of support rollers, which between them define a medium support plane. Over the medium support plane a print station is provided.
  • the print station generally comprises a printhead carriage translatable over the belt to print an image on a print medium on the belt in consecutive swaths. The print medium is moved in steps in between passes of the printhead carriage.
  • a large format hybrid printer is intended to be a productive engine capable of printing both on roll-to-roll media and on rigids.
  • the printer is equipped with a dual configuration with a loading device for two rolls. With this, two rolls can be printed in parallel next to each other so that the dual configuration increases the productivity of the printer.
  • the method is suited for loading a print medium for tandem printing on a printer comprising an endless transport belt extending over a suction chamber assembly, so that a negative pressure can be applied in the suction chamber assembly to draw a print medium against the transport belt, which suction chamber assembly defines a plurality of vacuum zones extending in a transport direction of the transport belt, in which vacuum zones negative pressures can be applied independent of one another.
  • the method further comprises the step of:
  • the frictional holding force between the transport belt and the already loaded print medium is proportional to the normal force on the said print medium.
  • the normal force in turn is proportional to the negative pressure in the vacuum zone facing said print medium.
  • the negative pressure is selected to be so small to allow slipping.
  • the negative pressure is substantially zero or near-zero with respect to the ambient.
  • the to be loaded print medium is sucked against the transport belt with a relatively high negative pressure. This allows a leading portion of this print medium to be placed on the belt, so that it is held securely against it.
  • this print medium moves with the belt in the transport direction to e.g. a take-up roller.
  • the already loaded print medium remains substantially in place, since the belt slips past it. Printing on the already loaded print medium can then resume substantially at the position where printing was stopped to load the other print medium. No print media is thus wasted and the loading is simplified. Thereby, the object of the present invention has been achieved.
  • the vacuum zones are parallel to one another, so that multiple print media can be transported besides one another, wherein different negative pressure can be applied to different print media.
  • the method further comprises the steps of driving the transport belt, so that a leading edge of the second print medium moves with the transport belt in the transport direction, while the first print medium remains stationary.
  • the pressure difference between the first and second vacuum zones is sufficiently great, so that the to be loaded print medium is adhered to be the belt, while the already loaded print medium is substantially disengaged, so that it remains in position over the second vacuum zone. It will be appreciated that the slipping may result in minor displacement of the already loaded print medium, of e.g. several millimeters or centimeters. It will be appreciated that the relatively low negative pressure may be zero or near-zero with respect to atmospheric pressure.
  • the method further comprises the step of releasably adhering or attaching a leading portion of the second print medium to the transport belt over the vacuum zone by means of the second negative pressure applied in the second vacuum zone.
  • the second negative pressure applied to at least an upstream portion of the second vacuum zone is sufficiently large to hold the leading portion in place on the belt.
  • the loading of the second print medium is performed in between printing two subsequent images on the first print medium. In between subsequent images generally a blank or non-printed space is present.
  • the first vacuum zone is at a relatively large negative pressure, preferably comparable to the second negative pressure, so that the first print medium is adhered to the belt for transporting it in the transport direction.
  • the pressure in the first vacuum zone is reduced to the first, relatively low negative pressure. This prevents the first print medium from substantially moving forward, as the belt moves the second print medium forward in the transport direction.
  • Fig. 1 shows a wide format inkjet printer 1.
  • the wide-format printer 1 comprises an inkjet printing assembly 7 for printing on a print medium 15.
  • the print medium 15 in Fig. 1 is a relatively rigid substrate, such as a panel.
  • the print medium 15 is supplied from a media input unit 14, which may be configured for storing a plurality of such print media 15 and supplying these to the printer 1.
  • the printer 1 comprises transport means for receiving and transporting the print medium 15 along the inkjet printing assembly 7.
  • the transport means comprise an endless transport belt 4 supported on a plurality of support rollers 3A, 3B, 3C. At least one of the support rollers 3A, 3B, 3C is provided with driving means for moving the belt 4. Additionally, one or more one of the support rollers 3A, 3B, 3C may be configured to be moved and/or tilted to adjust and control the lateral position of the belt 4.
  • the printer 1 is provided with at least one sensor or detector, such as a CCD camera or area camera, to determine the relative position of belt 4 and/or the print medium 15. Data from said at least one sensor or detector may be applied to control the position of the belt 4 and/or the print medium 15.
  • the at least one sensor or detector is positioned in or at a housing (not shown) of the printer 1 and is configured to detect the print medium 15 before transporting the print medium 15 or before the print medium reaches the print station 7. By using cameras the print medium 15 can be detected over a full width of the medium support plane, and before the print station 7 will start printing on the print medium 15.
  • the at least one sensor or detector can also sense or see alignment bars (not shown) positioned on the media input unit 14 extending towards the medium support plane. According to an alternative embodiment the at least one sensor or detector is integrated in the medium support plane.
  • the belt 4 is further provided with through-holes and a suction chamber assembly 5 in connection with a suction source (not shown), such that a vacuum pressure may be applied to the print medium 15 via the through-holes in the belt 4.
  • the vacuum pressure adheres the print medium 15 flatly to the belt 4 and prevents displacement of the print medium 15 with respect to the belt 4. Due to this holding the belt 4 is able to transport the print medium 15.
  • suitable transport means such as rollers, steppers, etc., may alternatively be applied.
  • the print medium 15 may be transported stepwise and/or in continuous movement.
  • the ejection of the marking material from the print heads is performed in accordance with data provided in the respective print job.
  • the timing by which the droplets of marking material are released from the print heads determines their position on the print medium 15.
  • the timing may be adjusted based on the position of the inkjet printing assembly 7 along the first guide beam 6.
  • the above mentioned sensor 8 may therein be applied to determine the relative position and/or velocity of the inkjet printing assembly 7 with respect to the print medium 15. Based upon data from the sensor 8, the release timing of the marking material may be adjusted.
  • marking material may be spilled and stay on a nozzle surface of the print heads.
  • the marking material present on the nozzle surface may negatively influence the ejection of droplets and the placement of these droplets on the print medium 15. Therefore, it may be advantageous to remove excess of marking material from the nozzle surface.
  • the excess of marking material may be removed for example by wiping with a wiper and/or by application of a suitable anti-wetting property of the surface, e.g. provided by a coating.
  • the marking materials may require treatment to properly fixate them on the print medium.
  • a fixation unit 10 is provided downstream of the inkjet printing assembly 7.
  • the fixation unit 10 may emit heat and/or radiation to facilitate the marking material fixation process.
  • the fixation unit 10 is a radiation emitter, which emits light of certain frequencies, which interacts with the marking materials, for example UV light in case of UV-curable inks.
  • the fixation unit 10 in Fig. 1 is translatable along a second guide beam 9.
  • Other fixation units 10, such as page-wide curing or drying stations may also be applied.
  • the inkjet printing assembly 7 may be provided with a further fixation unit on the same carriage which holds the print heads. This further fixation unit can be used to (partially) cure and/or harden the marking materials, independent of or interaction with the fixation unit 10.
  • the wide-format printer 1 furthermore comprises a user interface 11 for receiving print jobs and optionally for manipulating print jobs.
  • the user interface 11 may also be used to control the suction chamber assembly 5 for turning on or off the vacuum underneath the print belt 4.
  • the suction chamber assembly 5 has at least two separate parts underneath the medium support plane in order to allow independent loading and transporting of the print media of one or the other roll in case of dual roll printing.
  • the suction chamber assembly 5 defines by means of separate chambers a first vacuum zone 45 and a second vacuum zone 46.
  • Each vacuum zone 45, 46 is provided with its respective pressure regulator for setting a negative pressure in each respective vacuum zone 45, 46 independent of the other.
  • the pressure regulators may e.g. comprise valves or controllable pumps or fans.
  • the local user interface unit 11 is integrated to the print engine and may comprise a display unit and a control panel.
  • the printer 1 in Fig. 1 is a so-called hybrid printer, capable of handling both flexible media and rigid substrates.
  • the printer 1 operates in a first print situation, wherein the printer 1 is configured for transporting rigid substrates, such as the print medium 15.
  • rigid print media 15 may be panels for doors, walls, etc., corrugated media, plates formed of plastic or metal, etc.
  • the printer 1 in Fig. 1 is configured with a substantially linear transport path: from the media input device 14, the print medium 15 moves forward along the inkjet printing assembly 7 at a at substantially constant height.
  • the media input unit 14 and the receiving unit are positioned at the level of the medium support surface of the belt 4.
  • a flexible web medium 16 is supplied to the printer 1, which web medium 16 may be composed of e.g. paper, label stock, coated paper, plastic or textile.
  • the web medium 16 is supplied from the input roller 2A and extends across the belt 4 to the take-up roller 2B, where the web medium 16 is re-wound.
  • the printer 1 is configured to swiftly and efficiently switch between print modes.
  • Fig. 2 shows the printer being controlled in a tandem media printing mode. Therein a dual print configuration of two rolls also known as tandem print configuration is provided, but one or more than two rolls may be loaded and printed upon at the same time. According to the present invention in the tandem print configuration two rolls are loaded and driven independently.
  • the two rolls are nevertheless coupled via the belt 4 and according to the present invention decoupling of the driving of the rolls is achieved by turning on/off the separate vacuum zones.
  • the present invention is preferably applied to a print configuration of at least two rolls, for example a tandem print configuration of two rolls.
  • the controller controls the pressure regulators, so that a sufficiently large negative pressure is applied to all print media on the belt 4 to prevent the belt slipping with respect to the print media.
  • control unit 12 comprises a Central Processing Unit (CPU) 31, a Graphical Processor Unit (GPU) 32, a Random Access Memory (RAM) 33, a Read Only Memory (ROM) 34, a network unit 36, an interface unit 37, a hard disk (HD) 35 and an image processing unit 39 such as a Raster Image Processor (RIP).
  • CPU Central Processing Unit
  • GPU Graphical Processor Unit
  • RAM Random Access Memory
  • ROM Read Only Memory
  • network unit 36 an interface unit 37
  • HD hard disk
  • image processing unit 39 such as a Raster Image Processor
  • the aforementioned units 31 - 37 are interconnected through a bus system 38.
  • the control unit 12 may also be a distributed control unit.
  • the CPU 31 controls the printing system 1 in accordance with control programs stored in the ROM 34 or on the HD 35 and the local user interface panel 11.
  • the CPU 31 also controls the image processing unit 39 and the GPU 32.
  • the ROM 34 stores programs and data such as boot program, set-up program, various set-up data or the like, which are to be read out and executed by the CPU 31.
  • the hard disk 35 is an example of a non-volatile storage unit for storing and saving programs and data which make the CPU 31 execute a print process to be described later.
  • the hard disk 35 also comprises an area for saving the data of externally submitted print jobs.
  • the programs and data on the HD 35 are read out onto the RAM 33 by the CPU 31 as needed.
  • the RAM 33 has an area for temporarily storing the programs and data read out from the ROM 34 and HD 35 by the CPU 31, and a work area which is used by the CPU 31 to execute various processes.
  • the interface unit 37 connects the control unit 12 to the client device 21 and to the printing system 1.
  • the network unit 36 connects the control unit 12 to the network N and is designed to provide communication with workstations and with other devices reachable via the network N.
  • the image processing unit 39 may be implemented as a software component running on an operation system of the control unit 12 or as a firmware program, for example embodied in a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC).
  • the image processing unit 39 has functions for reading, interpreting and rasterizing the print job data.
  • Said print job data contains image data to be printed (i.e. fonts and graphics that describe the content of the document to be printed, described in a Page Description Language or the like), image processing attributes and print settings.
  • Fig. 4 shows schematically the printer 1 seen from above provided with a two vacuum zones 45, 46 beneath the print belt (not shown).
  • the first vacuum zone 45 and the second vacuum zone 46 are different and separate vacuum zones beneath the print belt.
  • Print media 41 from a first roll core 43 is enabled to be transported in a transport direction Y to the output roll core 49 making use of the vacuum of the first vacuum zone 45 below the belt (not shown).
  • the belt just moves in the transport direction Y below print media 42 unwound from a second roll core 44 while the print media 42 unwound from the second roll core 44 is not moving, because the vacuum of the second vacuum zone 46 is turned off.
  • a printer state signal is received by the print controller that print media is intended to be loaded in the printer in order to facilitate printing on the print media when transported over the first part of the media support plane.
  • the controller switches from the tandem media printing mode to the tandem media loading mode.
  • a second step S2 the vacuum zone corresponding to the second part of the media support plane is turned off by controlling the respective pressure regulator.
  • the vacuum zone is turned off at a moment time that the printing of an image on the print media transported over the second part of the media support plane is completed, for example at a moment of time between the printing of two consecutive images on the print media transported over the second part of the media support plane.
  • the vacuum may not be entirely turned off, but be significantly reduced to e.g. to (near) atmospheric pressure to allow the belt to slip along the print medium.
  • a third step S3 the vacuum zone corresponding to the first part of the media support plane is turned on in order to enable a load of the print media in the printer.
  • the method ends in an end point B.
  • the first part of the media support plane is mentioned in the first step S1.
  • the same method applies mutatis mutandis to the second part when a printer state signal is received by the print controller that print media is intended to be loaded in the printer in order to facilitate print on the print media when transported over the second part of the media support plane.
  • Fig. 5B discloses an example of a second method according to the invention.
  • the second method starts in a starting point C which leads to a first step T1.
  • a printer state signal is received from the print controller that print media has been loaded in the printer in order to facilitate printing on the print media when transported over the first or second part of the media support plane. This returns the controller to the tandem media printing mode.
  • a second step T2 the corresponding vacuum zone is turned on.
  • turning on the vacuum zone is meant that a vacuum pressure is present in the vacuum zone.
  • the second step T2 may be skipped when the corresponding vacuum zone is already turned on.
  • the vacuum zone other than the corresponding vacuum zone has been turned off while a roll has already been loaded and even printed upon, it may be turned on again together with the second step T2 to facilitate simultaneous printing on print media unwound from both rolls.
  • the second method ends in an end point D.
  • the first method shown in Fig. 5A and the second method shown in Fig. 5B may be combined into a third method by coupling end point B of the first method to the starting point C of the second method.
  • FIG. 8 schematically shows a non-transitory software medium 80 according to the invention.
  • the software medium 80 comprises executable code 82 configured to, when executed, perform the method according to the invention, e.g. as described with respect to either the printing system 1 shown in FIG. 1 or the method of controlling the printing system 1 according to the present invention and/or according to any of the variants and modifications of the printing system 1 and/or of the method described herein.
  • the non-transitory software medium 80 may, specifically, be formed as a CD or a CD-ROM, a DVD or a DVD-ROM, a BluRay disc or a BluRay-ROM disc, a magnetic hard drive, a solid state disk (SSD) hard drive, a USB memory device and so on.

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  • Handling Of Sheets (AREA)

Abstract

A method for a printer comprising a transport device comprising an endless transport belt supported on a pair of support rollers, which between them define a medium support plane, over which medium support plane a print station is provided, wherein printer is configured to transport print media from an input station by the transport belt in a dual configuration at the same speed to an output station perpendicular to a scanning direction of the print station on the medium support plane, and wherein a plurality of vacuum zones beneath the transport belt comprises a first vacuum zone which is beneath and extends over a first part of the medium support plane over which first print media is intended to be transported to the output station, and a second vacuum zone which is beneath and extends over a second part of the medium support plane over which second print media is intended to be transported to the output station, wherein the second vacuum zone is adjacent to the first vacuum zone in the scanning direction, and the method comprises the steps of independently in time turning off the first or second vacuum zone in order to stop delivering a vacuum pressure to the corresponding part of the medium support plane for enabling a load of the corresponding print media in the printer and/or a positioning of the corresponding print media on the medium support plane, and independently in time turning on the first or second vacuum zone in order to deliver a vacuum pressure to the corresponding part of the medium support plane for enabling a transport of the corresponding print media over the corresponding part of the medium support plane.

Description

    BACKGROUND OF THE INVENTION 1. Field of the invention
  • The present invention relates to a method for loading a print medium for tandem printing on a printer suited for tandem printing, to such a printer, and to a software product for performing the method on the printer.
    • 2. Description of Background Art
  • Large format hybrid printers are configured to print both rigid substrates as well as flexible print media. Such a printer may comprise a transport device comprising an endless transport belt supported on at least one pair of support rollers, which between them define a medium support plane. Over the medium support plane a print station is provided. The print station generally comprises a printhead carriage translatable over the belt to print an image on a print medium on the belt in consecutive swaths. The print medium is moved in steps in between passes of the printhead carriage.
  • A large format hybrid printer is intended to be a productive engine capable of printing both on roll-to-roll media and on rigids. To be productive on rolls the printer is equipped with a dual configuration with a loading device for two rolls. With this, two rolls can be printed in parallel next to each other so that the dual configuration increases the productivity of the printer.
  • One of the limitations in such a hybrid printer in which the print belt is used to transport the media is that in a dual configuration the media of both rolls will be transported by the belt at the same speed. A negative pressure or vacuum applied via the belt is used to transport the media and to keep the media flat during printing in order to avoid printhead crashes. A problem arises when loading and feeding a second roll while a first roll is already loaded and fed. The transport of media from the second roll from input side to output side in order to be taped to the output roll also results in a lot of media waste on the already loaded first roll.
  • It is noted that the printer is able to print from one roll if the other roll is not loaded.
  • Other printers don't use the print belt to transport the media from input side to output side. In general this makes it a hassle or at least less usable to load rolls, but since the user just has to get the media from the input to the output side the media waste is avoided.
    • SUMMARY OF THE INVENTION
  • It is an object of the invention to provide a printer with an improved productivity and a reduction of waste of print medium.
  • In accordance with the present invention, a method for printing according to claim 1 is provided.
  • The method is suited for loading a print medium for tandem printing on a printer comprising an endless transport belt extending over a suction chamber assembly, so that a negative pressure can be applied in the suction chamber assembly to draw a print medium against the transport belt, which suction chamber assembly defines a plurality of vacuum zones extending in a transport direction of the transport belt, in which vacuum zones negative pressures can be applied independent of one another. The method further comprises the step of:
    • applying a first negative pressure in a first vacuum zone, while a first print medium is positioned over the first vacuum zone, so that the transport belt is able to slip along the first print medium; and
    • applying a second negative pressure larger than the first negative pressure in a second vacuum zone different from the first one, so that a second print medium can be transported with respect to first print medium by the transport belt in the transport direction.
  • It is the insight of the inventors that media waste when loading a new print medium during tandem printing can be reduced by allowing an already loaded print medium to remain stationary as the new print medium is being transported from an input roller to a take-up roller. It is the further insight of the inventors that when a single transport belt is applied for transporting both print media in tandem, the already loaded print media can be allowed remain stationary by allowing it to slip with respect to the transport belt, while the transport belt holds and thus moves the second print medium forwards. Thereto, in the vacuum zone facing the already loaded print medium, a first negative pressure is applied. The first negative pressure is selected to be so small, that the transport belts slips past the already loaded print medium. The frictional holding force between the transport belt and the already loaded print medium is proportional to the normal force on the said print medium. The normal force in turn is proportional to the negative pressure in the vacuum zone facing said print medium. The negative pressure is selected to be so small to allow slipping. Preferably, the negative pressure is substantially zero or near-zero with respect to the ambient. The to be loaded print medium is sucked against the transport belt with a relatively high negative pressure. This allows a leading portion of this print medium to be placed on the belt, so that it is held securely against it. By driving the belt, this print medium moves with the belt in the transport direction to e.g. a take-up roller. The already loaded print medium remains substantially in place, since the belt slips past it. Printing on the already loaded print medium can then resume substantially at the position where printing was stopped to load the other print medium. No print media is thus wasted and the loading is simplified. Thereby, the object of the present invention has been achieved.
  • In an embodiment, the vacuum zones are parallel to one another, so that multiple print media can be transported besides one another, wherein different negative pressure can be applied to different print media.
  • In an embodiment, the method further comprises the steps of driving the transport belt, so that a leading edge of the second print medium moves with the transport belt in the transport direction, while the first print medium remains stationary. The pressure difference between the first and second vacuum zones is sufficiently great, so that the to be loaded print medium is adhered to be the belt, while the already loaded print medium is substantially disengaged, so that it remains in position over the second vacuum zone. It will be appreciated that the slipping may result in minor displacement of the already loaded print medium, of e.g. several millimeters or centimeters. It will be appreciated that the relatively low negative pressure may be zero or near-zero with respect to atmospheric pressure.
  • In an embodiment, the transport belt slips past the first print medium, while the second print medium moves synchronously with the transport belt. The pressure applied to the first print medium is so small that it results in slipping between this print medium and the belt. The pressure applied to the second print medium is so large that is held onto the same belt in a non-slipping manner. It will be appreciated that the pressure difference with respect to the atmospheric pressure for the larger pressure is preferably at least 10%, very preferably at least 20%, even more preferably at least 50% greater than the smaller pressure.
  • In an embodiment, the method further comprises the step of releasably adhering or attaching a leading portion of the second print medium to the transport belt over the vacuum zone by means of the second negative pressure applied in the second vacuum zone. The second negative pressure applied to at least an upstream portion of the second vacuum zone is sufficiently large to hold the leading portion in place on the belt. By driving the belt with the leading portion on it, the leading portion can brought to the downstream end of the belt, thereby pulling additional material of the second print medium onto the belt.
  • In an embodiment, the method further comprises the step of printing on the first print medium while a relatively large negative pressure is applied to it, so that the first print medium moves with the belt, followed by the steps of:
    • stopping the transport of and printing on the first print medium; and
    • reducing the pressure applied to the first print medium to the first, relatively small negative pressure. During printing, the first print medium is prevented from slipping by applying this relatively large negative pressure, which is significantly greater than the reduced first, negative pressure. After loading the second print medium, the pressure applied to the first print medium is preferably increased substantially back to this relatively large negative pressure.
  • In an embodiment, the loading of the second print medium is performed in between printing two subsequent images on the first print medium. In between subsequent images generally a blank or non-printed space is present. During the printing of a first image on the first print medium, the first vacuum zone is at a relatively large negative pressure, preferably comparable to the second negative pressure, so that the first print medium is adhered to the belt for transporting it in the transport direction. When the first image has been printed and it has determined that a new print medium is to be loaded in tandem to the first, the pressure in the first vacuum zone is reduced to the first, relatively low negative pressure. This prevents the first print medium from substantially moving forward, as the belt moves the second print medium forward in the transport direction. After loading the second print medium, the pressure in the first vacuum zone is returned to the relatively large negative pressure suited for transporting the first print medium with the belt. The second image is then printed after moving the first medium to form (the rest of) the blank or non-printed space. By performing the loading operation in the period when the blank space is to be formed on the first print medium, some minor displacement of the first print medium due to the slipping of the belt will not be visible in the printed images.
  • In an embodiment, the printer further comprises a transport device comprising the endless transport belt supported on a plurality of support rollers, which between them define a medium support plane, over which medium support plane a print station is provided, wherein printer is configured to transport print media from an input station by the transport belt in a dual configuration at the same speed to an output station perpendicular to a scanning direction of the print station on the medium support plane, and wherein the plurality of vacuum zones beneath the transport belt comprises the first vacuum zone which is beneath and extends over a first part of the medium support plane over which first print media is intended to be transported to the output station, and the second vacuum zone which is beneath and extends over a second part of the medium support plane over which second print media is intended to be transported to the output station, wherein the second vacuum zone is adjacent to the first vacuum zone in the scanning direction, and the method further comprises the steps of:
    • independently in time turning off the first or second vacuum zone in order to stop delivering a vacuum pressure to the corresponding part of the medium support plane for enabling a load of the corresponding print media in the printer and/or a positioning of the corresponding print media on the medium support plane, and
    • independently in time turning on the first or second vacuum zone in order to deliver a vacuum pressure to the corresponding part of the medium support plane for enabling a transport of the corresponding print media over the corresponding part of the medium support plane.. The second vacuum zone is adjacent to the first vacuum zone in the scanning direction.
  • The problem of print medium waste during loading and feeding a second roll is solved by having the corresponding vacuum zone turned off during media loading and feeding. By having at least two separate vacuum zones for the left and the right side of the printer the vacuum can be independently turned off for the left or the right roll. This means that the printer has at least two vacuum zones. A first advantage of the method according to the present invention is easy roll loading by automatically transporting the media to the right position of the output roll. A second advantage is that a second roll is loaded without having the unload the first or creating a lot of media waste on this first roll.
  • According to an embodiment the print media wound up on a roll core.
  • According to an embodiment the print media is already printed upon on a first side of the print media, and the positioning of the print media comprises the sub-step of aligning the second side of print media in order to enable double-sided printing on the print media.
  • According to an embodiment the print media is unwound from a first roll core in the input station and the load of the print media in the printer comprises the sub-step of attaching the print media to a second roll core in the output station.
  • According to an embodiment the method comprises the steps of receiving a printer state signal that print media is intended to be loaded in the printer in order to facilitate printing on the print media when transported over the first part of the media support plane, turning off the vacuum zone corresponding to the second part of the media support plane, and turning on the vacuum zone corresponding to the first part of the media support plane in order to enable a load of the print media in the printer.
  • According to an embodiment the method comprises the steps of receiving a printer state signal that print media has been loaded in the printer in order to facilitate printing on the print media when transported over the first or second part of the media support plane, turning on the corresponding vacuum zone, and transporting the print media over the corresponding part of the media support plane in order to facilitate printing on the print media.
  • According to an embodiment the step of independently in time turning off the first or second vacuum zone comprises the step of turning off the first vacuum zone, while the second vacuum zone has been turned on. Since the second vacuum zone is turned on, print media may be transported and printed upon above the second vacuum zone. Since the first vacuum zone is turned off, printing on the corresponding print media is not possible.
  • According to an embodiment the step of independently in time turning on the first or second vacuum zone comprises the step of turning on the first vacuum zone, while the second vacuum zone has been turned off. Since the first vacuum zone is turned on, print media may be loaded and transported and printed upon above the first vacuum zone. Since the second vacuum zone is turned off, corresponding print media can not be printed upon.
  • According to an embodiment the step of independently in time turning off the first or second vacuum zone comprises the step of turning off the first vacuum zone, while the second vacuum zone has been turned off. Since both the first and second vacuum zone is turned off, printing on print media is not possible for both rolls.
  • According to an embodiment the step of independently in time turning on the first or second vacuum zone comprises the step of turning on the first vacuum zone, while the second vacuum zone has been turned on. Since both the first and second vacuum zone is turned on, print media may be transported and printed upon above the first and/or second vacuum zone.
  • The present invention further relates to a printer comprising:
    • an endless transport belt extending over a suction chamber assembly defining a plurality of vacuum zones, wherein each vacuum zone is provided with its respective pressure regulator for setting a negative pressure in the respective vacuum zone;
    • at least one input roller for supplying at least two print media in parallel to the transport belt, so that the print media can be transported and printed on in tandem while on the transport belt; and
    • a print controller configured to operate in a tandem media loading mode, wherein the controller controls:
      • a first pressure regulator of a first vacuum zone to apply a first negative pressure in a first vacuum zone, which first negative pressure is sufficiently small to allow the transport belt to slip along a first print medium when positioned over the first vacuum zone, when the transport belt is driven; and
      • a second pressure regulator of a second vacuum zone to apply a second negative pressure larger than the first negative pressure in a second vacuum zone different from the first one, which second negative pressure is sufficiently large, so that a second print medium can be held onto the transport belt, so that it is transported with respect to first print medium by the transport belt in the transport direction, when the transport belt is driven.
  • The suction chamber assembly defines at least two parallel vacuum zones. During regular tandem printing both vacuum zones apply a relatively large negative pressure to their respective print media, so that these are adhered to the belt for reliable transport therewith. In case a new print medium needs to be loaded during tandem printing, the controller reduces the negative pressure in the vacuum zone facing the other print medium already on the belt to a small and/or near zero negative pressure. Thereby, the force holding this print medium on the belt is much reduced, so that the belt and the print medium are able to move with respect to one another in the transport direction. In the other vacuum chamber, a relative large negative pressure is applied, so the leading portion of the new print medium can be attached to the belt. By driving the belt the leading portion can be transported to the downstream end of the belt, thereby spooling the new print medium onto the belt. Although both print media are supported on the same belt, only one of the print media is held to the belt and moves with it. The belt slips past the other print medium, so that it remains substantially in place. Printing on this latter print medium can thus be resumed at substantially the same position on the print medium as where printing was stopped before loading. Thus, an efficient and waste reducing printer is provided.
  • In an embodiment, the controller is further configured to operate in a tandem media printing mode, wherein the controller controls the belt to move at least the first print medium past a printing assembly for printing on it, and wherein the first pressure regulator is controlled to apply a relatively large negative pressure in the first vacuum zone, which relatively large negative pressure is greater than the first, relatively small negative pressure applied in the tandem media loading mode. The controller during printing operates in the tandem media printing mode, wherein relatively large negative pressure are applied to all print media on the belt, so that these are non-slippingly held against the belt. Printing is interrupted or paused when the controller enters the tandem media loading mode, wherein the negative pressure applied to the to be loaded print medium is reduced to ensure that the belt can slip along the first print medium.
  • In an embodiment, a single transport belt covers all the vacuum zones of the plurality of vacuum zones. The belt is preferably one-piece or integrally formed.
  • It will be appreciated that the negative pressure herein are with reference to the ambient pressure. Terms such as small(er), large(r), great(er), high(er), etc. are preferably to be considered to be with respect to the absolute value of the negative pressure, i.e. high(er), greater(er) and small(er) indicate pressures further removed from the ambient pressure than pressures indicated as small(er). Smaller may e.g. be defined to indicate a pressure value of less than preferably half, very preferably one third, even more preferably one fifth, or with even more preference one tenth of the 'larger/greater' pressure value. In a preferred embodiment, the smaller/lower pressure value applied herein is near-zero, i.e. at or close to atmospheric pressure.
  • In an embodiment, the controller in the tandem media loading mode is further configured for driving the transport belt wherein the first and second negative pressure have been set, so that the first print medium remains substantially stationary on the with respect to the suction chamber assembly, and wherein the second print medium moves with respect to the first print medium in the transport direction to a take-up roller. The to be loaded print medium is sucked securely against the belt, so that driving the belt moves the leading portion of this print medium with it into the transport direction. The negative pressure applied to the previously loaded print medium is so small that the belt slips past it without substantially moving it into the transport direction. This allows the to be loaded print medium to catch up with the already loaded print medium.
  • In an embodiment, the suction chamber assembly comprises a respective high pressure zone at the upstream end of each vacuum zone. The high pressure zone may be formed by a separate sub-chamber in the suction chamber assembly, which allows a relatively very large negative pressure to be applied to the leading portion of the print medium at the upstream end or side of the belt, preferably at or directly downstream of the upstream support roller for the belt. This allows the suction chamber assembly to hold the print medium against the belt, even when only a small portion of it is present on the belt.
  • The present invention also relates to a printer comprising a transport device comprising an endless transport belt supported on a pair of support rollers, which between them define a medium support plane, over which medium support plane a print station is provided, wherein printer is configured to transport print media from an input station by the transport belt in a dual configuration at the same speed to an output station perpendicular to a scanning direction of the print station on the medium support plane, and wherein a plurality of vacuum zones beneath the transport belt comprises a first vacuum zone which is beneath and extends over a first part of the medium support plane over which first print media is intended to be transported to the output station, and a second vacuum zone which is beneath and extends over a second part of the medium support plane over which second print media is intended to be transported to the output station, wherein the second vacuum zone is adjacent to the first vacuum zone in the scanning direction, and wherein the printer comprises a print controller which is configured to execute the steps of the method according to any one of the preceding claims.
  • According to an embodiment the printer is a roll-to-roll printer or a hybrid printer. The hybrid printer may process rolls of print media as well as rigids of print media.
  • The present invention also relates to a software product comprising program code on a machine-readable medium, which program code, when loaded into a print controller of a digital printer according to the present invention, causes the print controller to execute the steps of a method according to the present invention.
  • Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
    • Fig. 1 is a schematic perspective view of a printing system configured to print on rigids according to the present invention;
    • Fig. 2 is a schematic perspective view of a printing system in Fig. 1 configured to print on a roll of media according to the present invention;
    • Fig. 3 is a schematic diagram of a control unit of a printer according to Fig. 1 or 2;
    • Fig. 4 is a schematic top view of the printer with the vacuum zones;
    • Fig. 5A is a schematic block diagram illustrating the steps of a first method according to the present invention;
    • Fig. 5B is a schematic block diagram illustrating the steps of a second method according to the present invention; and
    • Fig. 6 is a diagram of a software product according to the present invention.
    DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • The present invention will now be described with reference to the accompanying drawings, wherein the same reference numerals have been used to identify the same or similar elements throughout the several views.
    • Printing system
  • Fig. 1 shows a wide format inkjet printer 1. The wide-format printer 1 comprises an inkjet printing assembly 7 for printing on a print medium 15. The print medium 15 in Fig. 1 is a relatively rigid substrate, such as a panel. The print medium 15 is supplied from a media input unit 14, which may be configured for storing a plurality of such print media 15 and supplying these to the printer 1. The printer 1 comprises transport means for receiving and transporting the print medium 15 along the inkjet printing assembly 7. In
  • Fig. 1, the transport means comprise an endless transport belt 4 supported on a plurality of support rollers 3A, 3B, 3C. At least one of the support rollers 3A, 3B, 3C is provided with driving means for moving the belt 4. Additionally, one or more one of the support rollers 3A, 3B, 3C may be configured to be moved and/or tilted to adjust and control the lateral position of the belt 4. The printer 1 is provided with at least one sensor or detector, such as a CCD camera or area camera, to determine the relative position of belt 4 and/or the print medium 15. Data from said at least one sensor or detector may be applied to control the position of the belt 4 and/or the print medium 15. The at least one sensor or detector is positioned in or at a housing (not shown) of the printer 1 and is configured to detect the print medium 15 before transporting the print medium 15 or before the print medium reaches the print station 7. By using cameras the print medium 15 can be detected over a full width of the medium support plane, and before the print station 7 will start printing on the print medium 15. The at least one sensor or detector can also sense or see alignment bars (not shown) positioned on the media input unit 14 extending towards the medium support plane. According to an alternative embodiment the at least one sensor or detector is integrated in the medium support plane.
  • The belt 4 is further provided with through-holes and a suction chamber assembly 5 in connection with a suction source (not shown), such that a vacuum pressure may be applied to the print medium 15 via the through-holes in the belt 4. The vacuum pressure adheres the print medium 15 flatly to the belt 4 and prevents displacement of the print medium 15 with respect to the belt 4. Due to this holding the belt 4 is able to transport the print medium 15. It will be appreciated that other suitable transport means, such as rollers, steppers, etc., may alternatively be applied. The print medium 15 may be transported stepwise and/or in continuous movement.
  • The inkjet printing assembly 7 is configured to translate along a first guide beam 6 in a scanning direction. The scanning direction is perpendicular to the direction in which the print medium is transported by the belt 4. The inkjet printing assembly 7 holds a plurality of print heads (not shown), which are configured to jet a plurality of different marking materials (different colors of ink, primers, coatings, etc.) on the print medium 15. Each marking material for use in the printing assembly 7 is stored in one of a plurality of containers arranged in fluid connection with the respective print heads for supplying marking material to said print heads to print an image on the print medium 15.
  • The ejection of the marking material from the print heads is performed in accordance with data provided in the respective print job. The timing by which the droplets of marking material are released from the print heads determines their position on the print medium 15. The timing may be adjusted based on the position of the inkjet printing assembly 7 along the first guide beam 6. The above mentioned sensor 8 may therein be applied to determine the relative position and/or velocity of the inkjet printing assembly 7 with respect to the print medium 15. Based upon data from the sensor 8, the release timing of the marking material may be adjusted.
  • Upon ejection of the marking material, some marking material may be spilled and stay on a nozzle surface of the print heads. The marking material present on the nozzle surface, may negatively influence the ejection of droplets and the placement of these droplets on the print medium 15. Therefore, it may be advantageous to remove excess of marking material from the nozzle surface. The excess of marking material may be removed for example by wiping with a wiper and/or by application of a suitable anti-wetting property of the surface, e.g. provided by a coating.
  • The marking materials may require treatment to properly fixate them on the print medium. Thereto, a fixation unit 10 is provided downstream of the inkjet printing assembly 7. The fixation unit 10 may emit heat and/or radiation to facilitate the marking material fixation process. In the example of Fig. 1, the fixation unit 10 is a radiation emitter, which emits light of certain frequencies, which interacts with the marking materials, for example UV light in case of UV-curable inks. The fixation unit 10 in Fig. 1 is translatable along a second guide beam 9. Other fixation units 10, such as page-wide curing or drying stations may also be applied. Further, the inkjet printing assembly 7 may be provided with a further fixation unit on the same carriage which holds the print heads. This further fixation unit can be used to (partially) cure and/or harden the marking materials, independent of or interaction with the fixation unit 10.
  • After printing, and optionally fixation, the print medium 15 is transported to a receiving unit (not shown). The receiving unit may comprise a take-up roller for winding up the print medium 15, a receiving tray for supporting sheets of print medium 15, or a rigid media handler, similar to the media input unit 14. Optionally, the receiving unit may comprise processing means for processing the medium 15 after printing, e.g. a posttreatment device such as a coater, a folder, a cutter, or a puncher.
  • The wide-format printer 1 furthermore comprises a user interface 11 for receiving print jobs and optionally for manipulating print jobs. The user interface 11 may also be used to control the suction chamber assembly 5 for turning on or off the vacuum underneath the print belt 4.
  • According to the present invention the suction chamber assembly 5 has at least two separate parts underneath the medium support plane in order to allow independent loading and transporting of the print media of one or the other roll in case of dual roll printing. The suction chamber assembly 5 defines by means of separate chambers a first vacuum zone 45 and a second vacuum zone 46. Each vacuum zone 45, 46 is provided with its respective pressure regulator for setting a negative pressure in each respective vacuum zone 45, 46 independent of the other. The pressure regulators may e.g. comprise valves or controllable pumps or fans. The local user interface unit 11 is integrated to the print engine and may comprise a display unit and a control panel.
  • Alternatively, the control panel may be integrated in the display unit, for example in the form of a touch-screen control panel. The local user interface unit 11 is connected to a control unit 12 connected to the printer 1. The control unit 12, for example a computer, comprises a processor adapted to issue commands to the printer 1, for example for controlling the print process. The printer 1 may optionally be connected to a network. The connection to the network can be via cable or wireless. The printer 1 may receive printing jobs via the network. Further, optionally, the control unit 12 of the printer 1 may be provided with an input port, such as a USB port, so printing jobs may be sent to the printer 1 via this input port.
    • Hybrid printing system
  • The printer 1 in Fig. 1 is a so-called hybrid printer, capable of handling both flexible media and rigid substrates. In Fig. 1, the printer 1 operates in a first print situation, wherein the printer 1 is configured for transporting rigid substrates, such as the print medium 15. Such rigid print media 15 may be panels for doors, walls, etc., corrugated media, plates formed of plastic or metal, etc. To handle these rigid print media 15, the printer 1 in Fig. 1 is configured with a substantially linear transport path: from the media input device 14, the print medium 15 moves forward along the inkjet printing assembly 7 at a at substantially constant height. The media input unit 14 and the receiving unit are positioned at the level of the medium support surface of the belt 4. In Fig. 2, a flexible web medium 16 is supplied to the printer 1, which web medium 16 may be composed of e.g. paper, label stock, coated paper, plastic or textile. The web medium 16 is supplied from the input roller 2A and extends across the belt 4 to the take-up roller 2B, where the web medium 16 is re-wound. The printer 1 is configured to swiftly and efficiently switch between print modes. Fig. 2 shows the printer being controlled in a tandem media printing mode. Therein a dual print configuration of two rolls also known as tandem print configuration is provided, but one or more than two rolls may be loaded and printed upon at the same time. According to the present invention in the tandem print configuration two rolls are loaded and driven independently. The two rolls are nevertheless coupled via the belt 4 and according to the present invention decoupling of the driving of the rolls is achieved by turning on/off the separate vacuum zones. The present invention is preferably applied to a print configuration of at least two rolls, for example a tandem print configuration of two rolls. In the tandem media printing mode the controller controls the pressure regulators, so that a sufficiently large negative pressure is applied to all print media on the belt 4 to prevent the belt slipping with respect to the print media.
    • Control
  • An embodiment of the control unit 12 is in more detail presented in Fig. 3. As shown in Fig. 3, the control unit 12 comprises a Central Processing Unit (CPU) 31, a Graphical Processor Unit (GPU) 32, a Random Access Memory (RAM) 33, a Read Only Memory (ROM) 34, a network unit 36, an interface unit 37, a hard disk (HD) 35 and an image processing unit 39 such as a Raster Image Processor (RIP). The aforementioned units 31 - 37 are interconnected through a bus system 38. However, the control unit 12 may also be a distributed control unit.
  • The CPU 31 controls the printing system 1 in accordance with control programs stored in the ROM 34 or on the HD 35 and the local user interface panel 11. The CPU 31 also controls the image processing unit 39 and the GPU 32. The ROM 34 stores programs and data such as boot program, set-up program, various set-up data or the like, which are to be read out and executed by the CPU 31. The hard disk 35 is an example of a non-volatile storage unit for storing and saving programs and data which make the CPU 31 execute a print process to be described later. The hard disk 35 also comprises an area for saving the data of externally submitted print jobs. The programs and data on the HD 35 are read out onto the RAM 33 by the CPU 31 as needed. The RAM 33 has an area for temporarily storing the programs and data read out from the ROM 34 and HD 35 by the CPU 31, and a work area which is used by the CPU 31 to execute various processes. The interface unit 37 connects the control unit 12 to the client device 21 and to the printing system 1. The network unit 36 connects the control unit 12 to the network N and is designed to provide communication with workstations and with other devices reachable via the network N. The image processing unit 39 may be implemented as a software component running on an operation system of the control unit 12 or as a firmware program, for example embodied in a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). The image processing unit 39 has functions for reading, interpreting and rasterizing the print job data. Said print job data contains image data to be printed (i.e. fonts and graphics that describe the content of the document to be printed, described in a Page Description Language or the like), image processing attributes and print settings.
  • Fig. 4 shows schematically the printer 1 seen from above provided with a two vacuum zones 45, 46 beneath the print belt (not shown). For convenience reasons the print unit 7 and the print belt 4 have been left out of Fig. 4. The first vacuum zone 45 and the second vacuum zone 46 are different and separate vacuum zones beneath the print belt. Print media 41 from a first roll core 43 is enabled to be transported in a transport direction Y to the output roll core 49 making use of the vacuum of the first vacuum zone 45 below the belt (not shown). At the same time the belt just moves in the transport direction Y below print media 42 unwound from a second roll core 44 while the print media 42 unwound from the second roll core 44 is not moving, because the vacuum of the second vacuum zone 46 is turned off. The print media 42 is not moving in the transport direction Y and cannot be printed upon. The print media 41 from the first roll core 43 is automatically transported over the belt in order to be taped 40 on the fly to the output roll core 48, while the print media 41 is not moving and is not printed upon. The transport direction Y is perpendicular to the scanning direction X of the print unit of the printer 1.
  • Fig. 5A discloses an example of a first method according to the invention. The first method starts in a starting point A which leads to a first step S1.
  • In the first step S1 a printer state signal is received by the print controller that print media is intended to be loaded in the printer in order to facilitate printing on the print media when transported over the first part of the media support plane. Thereby, the controller switches from the tandem media printing mode to the tandem media loading mode.
  • In a second step S2 the vacuum zone corresponding to the second part of the media support plane is turned off by controlling the respective pressure regulator. By turning off the vacuum zone is meant that the vacuum pressure is not available anymore, but only the ambient pressure is present. Preferably the vacuum zone is turned off at a moment time that the printing of an image on the print media transported over the second part of the media support plane is completed, for example at a moment of time between the printing of two consecutive images on the print media transported over the second part of the media support plane. It will be appreciated that alternatively the vacuum may not be entirely turned off, but be significantly reduced to e.g. to (near) atmospheric pressure to allow the belt to slip along the print medium.
  • In a third step S3 the vacuum zone corresponding to the first part of the media support plane is turned on in order to enable a load of the print media in the printer.
  • The method ends in an end point B.
  • According to the method shown in Fig. 5A the first part of the media support plane is mentioned in the first step S1. However the same method applies mutatis mutandis to the second part when a printer state signal is received by the print controller that print media is intended to be loaded in the printer in order to facilitate print on the print media when transported over the second part of the media support plane.
  • Fig. 5B discloses an example of a second method according to the invention.
  • The second method starts in a starting point C which leads to a first step T1.
  • In the first step T1 a printer state signal is received from the print controller that print media has been loaded in the printer in order to facilitate printing on the print media when transported over the first or second part of the media support plane. This returns the controller to the tandem media printing mode.
  • In a second step T2 the corresponding vacuum zone is turned on. By turning on the vacuum zone is meant that a vacuum pressure is present in the vacuum zone. The second step T2 may be skipped when the corresponding vacuum zone is already turned on. When the vacuum zone other than the corresponding vacuum zone has been turned off while a roll has already been loaded and even printed upon, it may be turned on again together with the second step T2 to facilitate simultaneous printing on print media unwound from both rolls.
  • In a third step T3 the print media is transported over the corresponding part of the media support plane in order to facilitate printing on the print media.
  • The second method ends in an end point D.
  • The first method shown in Fig. 5A and the second method shown in Fig. 5B may be combined into a third method by coupling end point B of the first method to the starting point C of the second method.
  • While the steps of the method in Fig. 5A and the steps of the method in Fig. 5B are executed, print media cannot be transported or printed upon on the other part of the medium support plane, since the vacuum pressure is turned off in the other vacuum zone, independently from the state of the corresponding vacuum zone, i.e. independently from a turning on or turning off of the corresponding vacuum zone. The state of turning on of the other vacuum zone is advantageous since there is less waste of print media of the other roll.
  • FIG. 8 schematically shows a non-transitory software medium 80 according to the invention. The software medium 80 comprises executable code 82 configured to, when executed, perform the method according to the invention, e.g. as described with respect to either the printing system 1 shown in FIG. 1 or the method of controlling the printing system 1 according to the present invention and/or according to any of the variants and modifications of the printing system 1 and/or of the method described herein.
  • The non-transitory software medium 80 may, specifically, be formed as a CD or a CD-ROM, a DVD or a DVD-ROM, a BluRay disc or a BluRay-ROM disc, a magnetic hard drive, a solid state disk (SSD) hard drive, a USB memory device and so on.
  • Although specific embodiments of the invention are illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations exist. It should be appreciated that the exemplary embodiment or exemplary embodiments are examples only and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.
  • It will also be appreciated that in this document the terms "comprise", "comprising", "include", "including", "contain", "containing", "have", "having", and any variations thereof, are intended to be understood in an inclusive (i.e. non-exclusive) sense, such that the process, method, device, apparatus or system described herein is not limited to those features or parts or elements or steps recited but may include other elements, features, parts or steps not expressly listed or inherent to such process, method, article, or apparatus. Furthermore, the terms "a" and "an" used herein are intended to be understood as meaning one or more unless explicitly stated otherwise. Moreover, the terms "first", "second", "third", etc. are used merely as labels, and are not intended to impose numerical requirements on or to establish a certain ranking of importance of their objects.
  • The present invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims (15)

  1. A method for loading a print medium for tandem printing on a printer comprising an endless transport belt (4) extending over a suction chamber assembly (5), so that a negative pressure can be applied in the suction chamber assembly (5) to draw a print medium (15, 16A, 16B) against the transport belt (4), which suction chamber assembly (5) defines a plurality of vacuum zones (45, 46) extending in a transport direction (Y) of the transport belt (4), in which vacuum zones (45, 46) negative pressures can be applied independent of one another, the method comprising the steps of:
    - applying a first negative pressure in a first vacuum zone (45, 46), while a first print medium (16A, 16B) is positioned over the first vacuum zone (45, 46), so that the transport belt (4) is able to slip along the first print medium (16A, 16B); and
    - applying a second negative pressure larger than the first negative pressure in a second vacuum zone (45, 46) different from the first one, so that a second print medium (16A, 16b) can be transported with respect to first print medium (16A, 16B) by the transport belt (4) in the transport direction (Y).
  2. The method according to claim 1, further comprising the step of driving the transport belt (4), so that a leading edge of the second print medium (16A, 16b) moves with the transport belt (4) in the transport direction (Y), while the first print medium (16A, 16B) remains stationary.
  3. The method according to claim 2, wherein the transport belt (4) slips past the first print medium (16A, 16B), while the second print medium (16A, 16B) moves synchronously with the transport belt (4).
  4. The method according to any of the previous claims, further comprising the step of attaching a leading portion of the second print medium (16A, 16B) to the transport belt (4) over the vacuum zone (45, 46) by means of the second negative pressure applied in the second vacuum zone (45, 46).
  5. The method according to any of the previous claims, wherein the printer (1) further comprises a transport device comprising the endless transport belt (4) supported on a plurality of support rollers (3A, 3B, 3C), which between them define a medium support plane, over which medium support plane a print station (7) is provided, wherein printer (1) is configured to transport print media (15, 16) from an input station (14, 2A, 43, 44) by the transport belt (4) in a dual configuration at the same speed to an output station (2B, 48, 49) perpendicular to a scanning direction (X) of the print station (7) on the medium support plane, and wherein the plurality of vacuum zones (45, 46) beneath the transport belt (4) comprises the first vacuum zone (45) which is beneath and extends over a first part of the medium support plane over which first print media (41) is intended to be transported to the output station (49), and the second vacuum zone (46) which is beneath and extends over a second part of the medium support plane over which second print media (42) is intended to be transported to the output station (48), wherein the second vacuum zone (46) is adjacent to the first vacuum zone (45) in the scanning direction (X), and the method further comprises the steps of
    - independently in time turning off the first or second vacuum zone in order to stop delivering a vacuum pressure to the corresponding part of the medium support plane for enabling a load of the corresponding print media in the printer and/or a positioning of the corresponding print media on the medium support plane, and
    - independently in time turning on the first or second vacuum zone in order to deliver a vacuum pressure to the corresponding part of the medium support plane for enabling a transport of the corresponding print media over the corresponding part of the medium support plane.
  6. A method according to claim 5, wherein the print media is unwound from a first roll core in the input station and the load of the print media in the printer comprises the sub-step of attaching the print media to a second roll core in the output station.
  7. A method according to claim 5 or 6, wherein the method comprises the steps of
    - receiving a printer state signal that print media is intended to be loaded in the printer in order to facilitate printing on the print media when transported over the first part of the media support plane,
    - turning off the vacuum zone corresponding to the second part of the media support plane, and
    - turning on the vacuum zone corresponding to the first part of the media support plane in order to enable a load of the print media in the printer.
  8. A method according to any one of the claims 5 to 7, wherein the method comprises the steps of
    - receiving a printer state signal that print media has been loaded in the printer in order to facilitate printing on the print media when transported over the first or second part of the media support plane,
    - turning on the corresponding vacuum zone, and
    - transporting the print media over the corresponding part of the media support plane in order to print on the print media.
  9. A method according to any one of the claims 5 to 8, wherein the step of independently in time turning off the first or second vacuum zone comprises the step of turning off the first vacuum zone, while the second vacuum zone has been turned on.
  10. A method according to any one of the claims 5 to 9, wherein the step of independently in time turning on the first or second vacuum zone comprises the step of turning on the first vacuum zone, while the second vacuum zone has been turned off.
  11. A method according to any one of the claims 5 to 10, wherein the step of independently in time turning off the first or second vacuum zone comprises the step of turning off the first vacuum zone, while the second vacuum zone has been turned off.
  12. A method according to any one of the claims 5 to 11, wherein the step of independently in time turning on the first or second vacuum zone comprises the step of turning on the first vacuum zone, while the second vacuum zone has been turned on.
  13. A printer (1) comprising:
    - an endless transport belt (4) extending over a suction chamber assembly (5) defining a plurality of vacuum zones (45, 46), wherein each vacuum zone (45, 46) is provided with its respective pressure regulator for setting a negative pressure in the respective vacuum zone (45, 46);
    - at least one input roller (2A) for supplying at least two print media (16A, 16B) parallel to the transport belt (4), so that the print media (16A, 16B) can be transported and printed on in tandem while on the transport belt (16A, 16B); and
    - a print controller configured to operate in a tandem media loading mode, wherein the controller controls:
    - a first pressure regulator of a first vacuum zone (45, 46) to apply a first, negative pressure in a first vacuum zone (45, 46), which first negative pressure is sufficiently small to allow the transport belt (4) to slip along a first print medium (16A, 16B) when positioned over the first vacuum zone (45, 46) and the transport belt (4) is driven; and
    - a second pressure regulator of a second vacuum zone (45, 46) to apply a second negative pressure in a second vacuum zone (45, 46) different from the first one, which second negative pressure is sufficiently large, so that a second print medium (16A, 16b) can be held onto the transport belt (4), so that it is transported with respect to first print medium (16A, 16B) the by the transport belt (4) in the transport direction (Y), when the transport belt (4) is driven.
  14. The printer (1) according to claim 13, wherein the controller is further configured for driving the transport belt (4), wherein the first and second negative pressures have been set, so that the first print medium (16A, 16B) remains substantially stationary with respect to the suction chamber assembly (5), and wherein the second print medium (16A, 16B) moves with respect to the first print medium (16A, 16B) in the transport direction (Y) to a take-up roller (2B).
  15. A software product comprising program code on a machine-readable medium, which program code, when loaded into a print controller of a printer according to claim 13 or 14, causes the print controller to execute the steps of a method according to any one of the claims 1 - 12.
EP24164670.2A 2024-02-19 2024-03-19 A method for loading print media while tandem printing on a printer Pending EP4603290A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP24158396 2024-02-19

Publications (1)

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EP4603290A1 true EP4603290A1 (en) 2025-08-20

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040174421A1 (en) * 2003-01-10 2004-09-09 Masaaki Tsuji Ink-jet printer
US20080295721A1 (en) * 2007-06-04 2008-12-04 Dainippon Screen Mfg. Co., Ltd. Printing apparatus, holding device, printing method and program
ES2547473B1 (en) * 2014-04-03 2016-07-14 Comercial Industrial Maquinaria Cartón Ondulado, S.L. Introducing device for the supply of laminar bodies in a graphic printing station
US20210155431A1 (en) * 2019-11-21 2021-05-27 Jesus Francisco Barberan Latorre Substrate printing system
CN216033298U (en) * 2021-05-27 2022-03-15 深圳市润天智数字设备股份有限公司 Hard board printing equipment

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040174421A1 (en) * 2003-01-10 2004-09-09 Masaaki Tsuji Ink-jet printer
US20080295721A1 (en) * 2007-06-04 2008-12-04 Dainippon Screen Mfg. Co., Ltd. Printing apparatus, holding device, printing method and program
ES2547473B1 (en) * 2014-04-03 2016-07-14 Comercial Industrial Maquinaria Cartón Ondulado, S.L. Introducing device for the supply of laminar bodies in a graphic printing station
US20210155431A1 (en) * 2019-11-21 2021-05-27 Jesus Francisco Barberan Latorre Substrate printing system
CN216033298U (en) * 2021-05-27 2022-03-15 深圳市润天智数字设备股份有限公司 Hard board printing equipment

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