(19)
(11)EP 2 886 344 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
16.05.2018 Bulletin 2018/20

(21)Application number: 14198974.9

(22)Date of filing:  18.12.2014
(51)Int. Cl.: 
B41F 13/04  (2006.01)
B65H 23/00  (2006.01)
B41F 33/00  (2006.01)

(54)

Method for reducing web printing press start-up waste and related printing press

Verfahren zur Reduzierung von Rollendruckmaschinenstartabfall und zugehörige Druckmaschine

Procédé de réduction de déchets de démarrage de presse à imprimer à bobines et presse d'impression associée


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 19.12.2013 US 201361918364 P
09.12.2014 US 201414565031

(43)Date of publication of application:
24.06.2015 Bulletin 2015/26

(73)Proprietor: Goss International Americas, Inc.
Durham, NH 03824 (US)

(72)Inventors:
  • Rancourt, Michael Raymond
    Merrimack, NH 03054 (US)
  • Hoff, Howard, W.
    Lee, NH 03861 (US)
  • Schuler-Cossette, Laura
    Brentwood, NH 03833 (US)

(74)Representative: Lavoix 
Bayerstrasse 83
80335 München
80335 München (DE)


(56)References cited: : 
EP-A1- 0 891 864
DE-B1- 3 023 678
EP-A1- 2 749 414
GB-A- 1 557 652
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] The invention concerns a method for operating a web printing press according to the preamble of claim 1 and a press according to the preamble of claim 10. Such a method and a press are known from EP891864.
    A web printing press and a method for operating the web printing press is known from EP2749414 (prior art according to A54(3)EPC).
    Further printing presses and methods are known from DE3023678 and GB 1557652.

    BACKGROUND



    [0002] During makeready on a web printing press considerable waste can be generated. The images on the web must be properly registered and the proper ink film densities established to create a properly appearing image on a substrate.

    [0003] The substrate printed prior to proper registration and ink density establishment is considered waste and typically discarded.

    [0004] Variable cut-off web printing presses for printing a variety of substrates, for example for use in packaging are known. For example the GOSS SUNDAY 3000V variable cut-off printing press can print on cardboard, paper, plastic and other substrates.

    SUMMARY OF THE INVENTION



    [0005] The present invention provides a method for reusing substrate created during makeready of a web printing press, for example substrate not properly registered or inked during makeready or substrate properly registered and inked but not coated.

    [0006] The present invention provides a method for operating a web printing press comprising the steps of unwinding a substrate from a roll to define a web, during makeready, printing the web using at least one print unit, the makeready ending when the web is being printed to a desired standard, stopping the web after the makeready, rewinding the web on the roll so that the substrate printed during the make ready passes back through the print unit and unwinding again the rewound substrate to pass through the print unit.

    [0007] The method permits reuse of the substrate processed during makeready. Especially for images that need not be of exacting quality, such as many packaging applications. In addition, for expensive substrates, the present invention can significantly reduce start-up waste and reduce costs.

    [0008] The desired standard preferably is determined by measuring the optical densities of the printed images to within a desired target density. A color bar for example can be printed and measured by a sensor.

    [0009] Before the rewinding step, any web guides can be set to guide a reversing web.

    [0010] Also before the rewinding step, the at least one print unit preferably is thrown off impression to stop printing, and the printed substrate passes through any curing units, such as a dryer or UV curing unit, to set the ink. This step can insure that the web, once rewound, does not adhere and stick for future unwinding during the reprint step.

    [0011] Preferably, during the unwind again step, the substrate is reprinted, over the previous makeready images. However, if a coater is part of the print configuration, the coater is not run during the makeready, and if the makeready images are acceptable according to the desired standard, the substrate during the unwind again step could simply then be coated without necessarily requiring a reprinting, and the print unit set on impression once the rewound web is unwound again and a white web is reached.

    [0012] If the desired optical density on reaching white web (unprinted substrate) after the unwind again step is not acceptable, the stopping, rewinding and unwind again steps can be repeated.

    [0013] Ink keys can be preset prior to makeready, and then adjusted as a function of the desired optical density on the substrate during makeready.

    [0014] A job counter can track the substrate length or impression cylinder counts to track the substrate used during each makeready cycle.

    [0015] The present invention also provides a web printing press comprising a roll stand for a substrate roll, the roll stand including a reversible motor, at least one web guide for guiding a web unwound from the substrate roll, at least one print unit for printing the web during makeready, at least one sensor for sensing an image printed on the substrate and a controller for ending the makeready and rewinding the web as a function of an input from the sensor, so that the substrate printed during the makeready passes back through the print unit; and for unwinding again the rewound substrate to pass through the print unit.

    [0016] The sensor preferably includes an optical density sensor and a register sensor.

    [0017] The press can include at least one web guide for guiding a web unwound from the substrate roll, the web guide being a reversing web guide.

    [0018] The roll stand can include edge sensors and at least one web guide as well to insure proper rewinding.

    [0019] The at least one print unit preferably includes a plurality of print units, for example four, for color printing of the web.

    [0020] The print unit preferably is a variable cut-off print unit, and may have a plate and blanket cylinder on one side of the web, and an impression cylinder on the other. The print unit may be an offset lithographic print unit.

    [0021] The press preferably further includes at least one curing unit, such as a dryer or a UV curing unit.

    [0022] The press also further includes at least one counter for tracking substrate length or impression cylinder counts.

    [0023] The present invention also provides a printed product comprising a substrate, a first makeready printed image below a certain standard, and a second image overtop the first makeready printed image.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0024] Further features and advantages of the present invention shall now be described in greater detail according to the accompanying figures in the following detailed description.

    Fig. 1 shows a schematic view of a printing press according to the present invention during makeready;

    Fig. 2 shows a schematic view of the printing press of the present invention during a rewind step; and

    Fig. 3 shows a printed product according to the present invention.


    DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT



    [0025] Fig. 1 shows a web printing press 100 having a roll stand 120, a print unit section 140, a curing section 160 and a web processing section 180.

    [0026] Roll stand 120 may include a frame 122 supporting a roll 20 of a substrate, such as cardboard, paper, or film. A reversible motor 124 can unwind or rewind the substrate, and is direction and speed controllable by a controller 200. A web guide 126 can be controlled by and provide inputs to controller 200. Web guide 126 can include for example web edge and tension sensors, can also control both the unwinding and rewinding of the substrate onto roll 20 so that the roll 20 can be properly unwound and rewound.

    [0027] Motor 124 thus can unwind roll 20 to define a web 22, which can be guided by further web guides 130, 132, 134 through press 100.

    [0028] A job counter 150 or impression counter 156 or other sensor can be used to track the substrate used during a makeready cycle.

    [0029] Print unit section 140 can include print units 142, 144, 146, 148, for example printing cyan, magenta, yellow, and black respectively. Each print unit can include an ink supply 190 with ink keys, an impression cylinder 182, a blanket cylinder 184 and a plate cylinder 186. An individual drive motor can drive each print unit. Controller 200 can control each print unit, including the ink keys and their settings and the motors for the print units.

    [0030] Sensors, including for example a register sensor 152 and optical density sensor 154 thus can be provided downstream of the print unit section 140 and connected to controller 200 to provide inputs on image quality on web 22.

    [0031] Curing section 160 can include any curing units necessary for the substrates to be printed, for example a dryer such as a GOSS ECOCOOL dryer and/or a UV curing unit.

    [0032] A coater 170 can be provided to add a coating over the printed substrate, and can be provided prior to curing section 160, or, if after, can be provided with its own curer. For example coater 170 can provide a clear UV curable layer on web 22, and include a UV curing unit separate from curing section 160 if downstream of curing section 160.

    [0033] Web processing section 180 can include any standard web processing units to form signatures or individual products from web 22, and may include stampers, creasers, longitudinal cutters, crosscutters, and any other web processing units. Web processing section 180 in one embodiment then has all processing units used to form flat cardboard box products from printed and cured web 22.

    [0034] During makeready with the present invention both coater 170 and web processing section 180 are turned off, and the substrate permitted to run. Depending on the plant configuration and lengths, a reserve area downstream of the web processing section may be provided. Alternately, if desired, a diverted reserve area where the web 22 bypasses or is diverted from the web processing section may be provided for makeready substrate to be rolled back on roll 20. However, standard plant lengths may be sufficient for most or all makereadies and a downstream or diverted reserve area is not necessary.

    [0035] As shown in the Fig. 1 embodiment, during makeready, substrate is unwound from roll 20 to define web 22. Web 22 is printed with four colors by print units 142, 144, 146, 148. Web 22 is not coated or processed into individual products but rather collected.

    [0036] When controller 200, via sensors 152, 154, determines that web 22 is being printed to a desired standard, makeready stops. Ink keys at this points are properly set for the print job, and the print units cylinders properly regsistered.

    [0037] Controller 200 then stops the web 22 and throws the blanket cylinders and/or impression cylinders of the print units off impression. Web 22 is then run further without being printed until all printed images are cured in curing unit 160.

    [0038] After all the images are cured, the web, including the nonprinted section and the cured makerady print section, is rewound on roll 20 by reversing motor 124. Reversing web guides 126, 130, 132, 134 can be set to a reversing mode to ensure that web 22 is properly guided back onto roll 20. Web 22 printed during the makeready thus passes back through the print unit section 140, as shown in Fig. 2. Not all of the cured makeready web 22 need to be placed back onto roll 20 however to reduce rethreading time, although this is possible.

    [0039] The rewound roll 20 is then unwound again allowing the rewound substrate to pass through the print unit section 140, the print units being thrown back on impression and printing acceptable images over the imperfect makeready images.

    [0040] However, if coater 170 is part of the print configuration, coater 170 is not run during the makeready, and if the makeready images are acceptable, the substrate during the unwind again step could simply then be coated without necessarily requiring a reprinting.

    [0041] If, after printing has restarted, the desired optical density on reaching the images printed on a white web (i.e. not over the imperfect makeready images) after the unwind again step is for some reason not acceptable, the stopping, rewinding and unwind again steps can be repeated.

    [0042] Fig. 3 schematically shows a substrate 22, for example made of cardboard, and inked during makeready with an imperfect image 322, showing for example areas 324, 326 where keys have yet been properly adjusted for proper ink density. This substrate 22 and image 322, once cured for example by drying, is rewound on roll 20 after makeready when the keys have been properly adjusted, and then reprinted to form a printed product 422 having both imperfect image 322 and a post makeready image 522 printed overtop imperfect image 322. Due to the controller 200 and counter 150 and proper registration, the post makeready image 522 is printed almost directly over imperfect image 322. For many printing requirements, such as cardboard and other packaging, the resulting image combination on the makeready substrate 22 from images 322 and 522 is sufficient and the makeready substrate 22 can be fully reused.

    [0043] The printing press can have one or more of the following features:

    [0044] The at least one print unit includes a plurality of print units for color printing of the web.

    [0045] The print unit is a variable cut-off print unit.

    [0046] The print unit includes a plate and blanket cylinder on one side of the web, and an impression cylinder on the other.

    [0047] A printed product can comprise: a substrate, a first makeready printed image below a certain standard, and a second image overtop the first makeready printed image.


    Claims

    1. A method for operating a web printing press (100) comprising:

    unwinding a substrate (22) from a roll (20) to define a web;

    caracterized in that the method comprises

    during makeready, printing the web using at least one print unit (142, 144, 146, 148), the makeready ending when the web is being printed to a desired standard;

    stopping the web after the makeready;

    rewinding the web on the roll (20) so that the substrate printed during the makeready passes back through the print unit; and

    unwinding again the rewound substrate to pass through the print unit.


     
    2. The method as recited in claim 1 wherein the desired standard is determined by measuring optical densities of the printed images and comparing the measured optical densities to a desired target density.
     
    3. The method as recited in claim 1 or 2 further comprising, before the rewinding step, setting at least one web guide (126, 130, 132, 134) to guide a reversing web.
     
    4. The method as recited in any one of claims 1 to 3 further comprising, before the rewinding step, throwing off impression the at least one print unit, and passing the printed substrate (22) through a curing unit (160).
     
    5. The method as recited in claim 4 wherein the cured printed substrate is passed back through the print unit during the rewinding step.
     
    6. The method as recited in any one of claims 1 to 5 wherein, during the unwind again step, the substrate (22) is reprinted.
     
    7. The method as recited in any one of claims 1 to 6 wherein a coater (170) is not run during the makeready, and if the makeready images are acceptable according to the desired standard, the substrate during the unwinding again is coated.
     
    8. The method as recited in any one of claims 1 to 7 wherein if, after printing has restarted, a desired optical density on reaching unprinted substrate after the unwind again step is not acceptable, the stopping, rewinding and unwind again steps are repeated.
     
    9. The method as recited in any one of claims 1 to 8 further comprising tracking the substrate used during a makeready cycle.
     
    10. A web printing press (100) comprising:

    a roll stand (120) for a substrate roll (20),

    the roll stand including a reversible motor;

    at least one print unit (140) for printing the web during makeready;

    caracterized in that the web printing press comprises:

    at least one web guide (126, 130, 132, 134) for guiding a web unwound from the substrate roll;

    at least one sensor (152, 154) for sensing an image printed on the substrate; and

    a controller (200) for ending the makeready and rewinding the web on the substrate roll (20) as a function of an input from the sensor, so that the substrate printed during the makeready passes back through the print unit;

    and for unwinding again the rewound substrate to pass through the print unit.


     
    11. The press as recited in claim 10 wherein the sensor (152, 154) includes an optical density sensor or a register sensor.
     
    12. The press as recited in claim 10 or 11 further comprising at least one web guide for guiding a web (22) unwound from the substrate roll, the web guide being a reversing web guide.
     
    13. The press as recited in any one of claims 10 to 12 wherein the roll stand (120) includes at least one web guide to insure proper rewinding.
     
    14. The press as recited in any one of claims 10 to 13 further comprising at least one curing unit (160) for curing the printed substrate.
     
    15. The press as recited in any one of claims 10 to 14 further comprising at least one counter (150) for tracking substrate length.
     


    Ansprüche

    1. Verfahren zum Betreiben einer Rollendruckmaschine (100), umfassend:

    Abwickeln eines Bedruckstoffs (22) von einer Rolle (20), um eine Bahn zu definieren,

    dadurch gekennzeichnet, dass das Verfahren Folgendes umfasst:

    Bedrucken der Bahn während des Rüstens unter Verwendung mindestens eines Druckwerks (142, 144, 146, 148), wobei das Rüsten endet, wenn die Bahn mit einem gewünschten Standard bedruckt wird,

    Anhalten der Bahn nach dem Rüsten,

    Wiederaufwickeln der Bahn auf die Rolle (20), so dass der während des Rüstens bedruckte Bedruckstoff zurück durch das Druckwerk läuft, und

    erneutes Abwickeln des wiederaufgewickelten Bedruckstoffs, um durch das Druckwerk zu laufen.


     
    2. Verfahren nach Anspruch 1, wobei der gewünschte Standard durch Messen optischer Dichten der gedruckten Bilder und Vergleichen der gemessenen optischen Dichten mit einer gewünschten Zieldichte bestimmt wird.
     
    3. Verfahren nach Anspruch 1 oder 2, ferner vor dem Schritt des Wiederaufwickelns das Einstellen mindestens einer Bahnführung (126, 130, 132, 134) zum Führen einer rückwärts laufenden Bahn umfassend.
     
    4. Verfahren nach einem der Ansprüche 1 bis 3, ferner vor dem Schritt des Wiederaufwickelns das Abstellen des Drucks des mindestens einen Druckwerks und Führen des bedruckten Bedruckstoffs (22) durch ein Trocknungswerk (160) umfassend.
     
    5. Verfahren nach Anspruch 4, wobei der getrocknete bedruckte Bedruckstoff während des Schritts des Wiederaufwickelns zurück durch das Druckwerk geführt wird.
     
    6. Verfahren nach einem der Ansprüche 1 bis 5, wobei während des Schritts des erneuten Abwickelns der Bedruckstoff (22) erneut bedruckt wird.
     
    7. Verfahren nach einem der Ansprüche 1 bis 6, wobei während des Rüstens ein Beschichtungswerk (170) nicht zum Einsatz kommt, und wenn die während des Rüstens entstandenen Bilder gemäß dem gewünschten Standard akzeptabel sind, der Bedruckstoff während des erneuten Abwickelns beschichtet wird.
     
    8. Verfahren nach einem der Ansprüche 1 bis 7, wobei die Schritte des Anhaltens, des Wiederaufwickelns und des erneuten Abwickelns wiederholt werden, wenn nach dem erneuten Start des Druckens eine gewünschte optische Dichte nach dem Erreichen von unbedrucktem Bedruckstoff nach dem Schritt des erneuten Abwickelns nicht akzeptabel ist.
     
    9. Verfahren nach einem der Ansprüche 1 bis 8, ferner das Nachverfolgen des während eines Rüstzyklus verwendeten Bedruckstoffs umfassend.
     
    10. Rollendruckmaschine (100), umfassend:

    einen Rollenstand (120) für eine Bedruckstoffrolle (20), wobei der Rollenstand einen Reversiermotor enthält,

    mindestens ein Druckwerk (140) zum Bedrucken der Bahn während des Rüstens,

    dadurch gekennzeichnet, dass die Rollendruckmaschine Folgendes umfasst:

    mindestens eine Bahnführung (126, 130, 132, 134) zum Führen einer von der Bedruckstoffrolle abgewickelten Bahn,

    mindestens einen Sensor (152, 154) zum Abfühlen eines Bildes, das auf den Bedruckstoff gedruckt ist, und

    eine Steuerung (200) zum Beenden des Rüstens und Wiederaufwickeln der Bahn auf die Bedruckstoffrolle (20) in Abhängigkeit von einer Eingabe von dem Sensor, so dass der während des Rüstens bedruckte Bedruckstoff zurück durch das Druckwerk läuft, und zum erneuten Abwickeln des wiederaufgewickelten Bedruckstoffs, um durch das Druckwerk zu laufen.


     
    11. Druckmaschine nach Anspruch 10, wobei der Sensor (152, 154) einen Sensor für die optische Dichte oder einen Passersensor enthält.
     
    12. Druckmaschine nach Anspruch 10 oder 11, ferner mindestens eine Bahnführung zum Führen einer von der Bedruckstoffrolle abgewickelten Bahn (22) umfassend, wobei die Bahnführung eine Führung für eine rückwärts laufende Bahn ist.
     
    13. Druckmaschine nach einem der Ansprüche 10 bis 12, wobei der Rollenstand (120) mindestens eine Bahnführung umfasst, um ein korrektes Abwickeln zu gewährleisten.
     
    14. Druckmaschine nach einem der Ansprüche 10 bis 13, ferner mindestens ein Trocknungswerk (160) zum Trocknen des bedruckten Bedruckstoffs umfassend.
     
    15. Druckmaschine nach einem der Ansprüche 10 bis 14, ferner mindesten einen Zähler (150) zum Nachverfolgen einer Bedruckstofflänge umfassend.
     


    Revendications

    1. Procédé de fonctionnement d'une presse à imprimer à bobines (100) comprenant :

    le déroulage d'un substrat (22) d'un rouleau (20) afin de définir une bobine ;

    caractérisé en ce que le procédé comprend

    pendant la préparation, l'impression de la bobine à l'aide d'au moins une unité d'impression (142, 144, 146, 148), la préparation se terminant lorsque la bobine est imprimée selon une norme souhaitée ;

    l'arrêt de la bobine après la préparation ;

    le rembobinage de la bobine sur le rouleau (20) de sorte que le substrat imprimé pendant la préparation repasse par l'unité d'impression ; et

    le déroulage, à nouveau, du substrat rembobiné afin qu'il passe par l'unité d'impression.


     
    2. Procédé selon la revendication 1, dans lequel la norme souhaitée est déterminée en mesurant les densités optiques des images imprimées et en comparant les densités optiques mesurées avec une densité cible souhaitée.
     
    3. Procédé selon la revendication 1 ou 2, comprenant en outre, avant l'étape de rembobinage, le réglage d'au moins un guide de bobine (126, 130, 132, 134) afin de guider une bobine à retournement.
     
    4. Procédé selon l'une quelconque des revendications 1 à 3, comprenant en outre, avant l'étape de rembobinage, l'arrêt de l'impression de la au moins une unité d'impression, et le passage du substrat imprimé (22) par une unité de durcissement (160).
     
    5. Procédé selon la revendication 4, dans lequel le substrat imprimé durci passe à nouveau par l'unité d'impression pendant l'étape de rembobinage.
     
    6. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel, pendant l'étape de déroulage, le substrat (22) est réimprimé.
     
    7. Procédé selon l'une quelconque des revendications 1 à 6, dans lequel une coucheuse (170) n'est pas déclenchée pendant la préparation, et, si les images de préparation sont acceptables selon la norme souhaitée, un revêtement est appliqué sur le substrat pendant le déroulage.
     
    8. Procédé selon l'une quelconque des revendications 1 à 7, dans lequel, si, une fois que l'impression a redémarré, une densité optique souhaitée sur le substrat non imprimé après l'étape de déroulage n'est pas acceptable, les étapes d'arrêt, de rembobinage et de déroulage sont répétées.
     
    9. Procédé selon l'une quelconque des revendications 1 à 8, comprenant en outre le suivi du substrat utilisé pendant un cycle de préparation.
     
    10. Presse à imprimer à bobines (100) comprenant :

    un support de rouleau (120) destiné à un rouleau de substrat (20), le support de rouleau comprenant un moteur réversible ;

    au moins une unité d'impression (140) destinée à imprimer la bobine pendant la préparation ;

    caractérisée en ce que la presse à imprimer à bobines comprend :

    au moins un guide de bobine (126, 130, 132, 134) destiné à guider une bobine déroulée du rouleau de substrat ;

    au moins un capteur (152, 154) destiné à détecter une image imprimée sur le substrat ; et

    un contrôleur (200) destiné à mettre fin à la préparation et à rembobiner la bobine sur le rouleau de substrat (20) en fonction d'une entrée du capteur, de sorte que le substrat imprimé pendant la préparation repasse par l'unité d'impression ; et à dérouler à nouveau le substrat rembobiné afin qu'il passe par l'unité d'impression.


     
    11. Presse selon la revendication 10, dans laquelle le capteur (152, 154) comprend un capteur de densité optique ou un capteur à registre.
     
    12. Presse selon la revendication 10 ou 11, comprenant en outre au moins un guide de bobine destiné à guider une bobine (22) déroulée du rouleau de substrat, le guide de bobine étant un guide de bobine à retournement.
     
    13. Presse selon l'une quelconque des revendications 10 à 12, dans laquelle le support de rouleau (120) comprend au moins un guide de bobine destiné à garantir un rembobinage adéquat.
     
    14. Presse selon l'une quelconque des revendications 10 à 13, comprenant en outre au moins une unité de durcissement (160) destinée à durcir le substrat imprimé.
     
    15. Presse selon l'une quelconque des revendications 10 à 14, comprenant en outre au moins un compteur (150) destiné à suivre la longueur du substrat.
     




    Drawing












    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description