EP4086081A1 - Digital printing method - Google Patents

Abstract

The invention relates to a method for printing a surface of a base paper with a decoration using a digital printing system, the method having the following steps: a) providing a base paper whose surface is to be printed, b) applying a primer to the surface of the base paper, c) Drying the applied primer in a first dryer, d) printing the decoration onto the dried primer using a printing unit of the digital printing system, and e) drying the printed raw paper in a second dryer, with a room in which the method is carried out being ventilated and is air-conditioned so that the room has a homogeneous relative humidity.

Description

The invention relates to a method for printing a surface, in particular a paper, using a digital printer and/or a digital printing system.

Such methods have long been known from the prior art. A generic method has, for example, the following steps: a) providing a base paper whose surface is to be printed, b) applying a primer to the surface of the base paper, c) drying the applied primer in a first dryer, d) printing the decoration on the dried primer by means of a printing unit of the digital printing system and e) drying of the printed base paper in a second dryer.

Many parameters have an impact on the result of the printing process and have been used in the prior art to improve the result. From the EP 2 373 489 B1 it is known, for example, to use two different climate zones in which the paper to be printed is in different stages of the printing process. A similar procedure is also the EP 2 206 605 refer to. the EP 2 132 043 whereas deals with the setting of drying temperatures and suggests relatively lower temperatures.

In the EP 2 274 485 B1 on the other hand, the object to be printed is adjusted. The paper described there has a fiber structure that is provided with an ink absorbing mass before the actual printing, so that the fibers in the upper area are encased, but cavities between the encased fibers remain. In the EP 2 695 745 B1 on the other hand, a paper that has previously been provided with a thermosetting resin is printed. Here the resin forms at least one Part of the ink receiving layer. the US 10,814,648 B1 suggests using heavy paper with a grammage of up to 90 g.

With a digital printing system, it is also possible to print different decors and motifs one after the other. Such a method is, for example, from EP 2 727 740 B2 known.

A method according to the invention is characterized in that it is carried out in a room which is ventilated and air-conditioned in such a way that the room has a homogeneous relative humidity. Appropriate devices, for example air conditioning systems, fans or the like, are preferably used to ensure that the relative humidity in the room in which the method is carried out is homogeneous. This means, for example, that the relative humidity at different points in the room deviates from a mean value by less than 5%, preferably less than 3%, particularly preferably by less than 1%. The room is preferably a hall or room of a building. However, the room does not have to be delimited by structural elements such as walls or ceilings, even if this is an advantage. It can also be a conceptually delimited space that is part of a space delimited by structural elements.

A homogeneous relative humidity does not necessarily mean a homogeneous air temperature, even if that is an advantage. The relative humidity is the quotient of the actual humidity and the maximum possible humidity.

The relative humidity is preferably between 40% and 45%.

The room is preferably ventilated and air-conditioned in such a way that a homogeneous air temperature prevails in the room. The digital printing system is particularly preferably ventilated and air-conditioned in such a way that the relative humidity and/or the air temperature prevail in it. The first dryer and/or the second dryer particularly preferably dries at a heating temperature of 155.degree. C. to 250.degree. Preferably no markings along which the paper is cut are printed. The printed paper is preferably impregnated.

First, the actual printing of the surface is prepared. It preferably starts with an incoming inspection in the so-called incoming goods department. The workpiece to be printed is preferably a web of paper or a piece of paper cut from such a web. The paper can be printed as an endless paper web and then, for example, cut into suitable and required pieces, i.e. cut to a predetermined length. Alternatively, the paper web is cut to a specified length before printing or delivered as separate pieces, so-called sheets.

During the incoming inspection, different parameters of the delivered work piece, especially the paper, can be determined and compared with stored target values. These parameters preferably include the grammage, ie the weight of one square meter of the paper to be printed, and/or the basis weight of the paper in g/m2. Alternatively or additionally, the smoothness of the paper can also be determined according to Bekk. Bekk's smoothness is a method for characterizing the surface topography of smooth paper or films with a roughened surface. The measuring principle is based on the surface to be characterized being placed on a plane glass plate with a bore. A vacuum is applied via the hole, which sucks the sample surface onto the glass. The time taken for the vacuum to drop between two defined pressure points is measured. Bekk smoothness is measured in seconds. As an alternative or in addition to this, the porosity can also be measured according to Guerley, which is given in s/100 ml. Alternatively or additionally, the breaking load can be measured, which is given in N/15mm, for example, and is preferably measured when the workpiece is wet and/or dry. Alternatively or in addition to this, the wet elongation can be measured according to Mütek, which is given in %. It is preferably measured along a longitudinal direction and/or a transverse direction, which are preferably perpendicular to one another. Alternatively or additionally, the pH value, an ash content in %, a color value, preferably with the ACMS system ("Advanced Color Measurement System"), which is offered, for example, by the company ipac and can particularly preferably be measured in a spatially resolved manner, a degree of whiteness preferably with the ACMS system and/or a wet tensile strength can be determined.

Preferably white paper accounts for about 70% of the materials to be printed. The proportion of cream-colored paper is about 10% and another 5% is preferably accounted for by light beige, beige, brown and gray paper. The incoming goods checks are preferably carried out for each of these types of paper, it being quite advantageous to store different target values for the parameters to be determined for different types of paper in a database.

The paper, which is preferably available as a roll of paper, is then temporarily stored so that it can acclimate, i.e. adapt to the parameters of the production facility. This concerns, for example, the temperature of an outer part and a core of the roll, which are preferably the same. It is preferably taken into account whether the printing takes place during summer operation or winter operation, which can have an impact on the duration of the interim storage, for example. Moisture is preferably measured. On the one hand, the humidity of the paper roll or the respective workpiece to be printed upon receipt of goods (receipt humidity), in storage (storage humidity) and when ready for the printing process (ready-to-read humidity) is of interest, but on the other hand also the humidity within the warehouse in which the paper roll is temporarily stored is of interest, and within the production facility, for example the workshop.

Paper rolls are preferably used which have a diameter of up to 125 cm and/or weigh up to 1.5 t. The paper web is wound on a core which is preferably 3" or 6" in diameter. They have a width of 1300 mm to 2070 mm and/or a grammage of at least 35 g, preferably at least 50 g to at most 75 g. It is preferably a decorative paper which is particularly preferably pre-treated, for example pre-impregnated with a substance. The paper can be obtained from a single supplier or from several suppliers, with the target values that are stored for the individual parameters to be determined preferably being independent of the source of supply of the paper.

In addition to the workpiece to be printed, ie in particular the paper, the printing ink to be used is preferably also subjected to an incoming inspection will. Preferably, a CRYK (cyan, red, yellow, black) ink, which is water-based, is used. Such an ink is offered by Staedtler, for example. Preferably, each purchased batch of printing ink must be released in an incoming inspection, in that parameters are preferably measured and compared with target values. This is done, for example, by the supplier, for example Staedtler, and is then usually their know-how. As an alternative or in addition to this, the incoming inspection is carried out by KBA (manufacturer of digital printing systems: König und Bauer AG), whereby the supplier preferably sends a small or very small sample directly to KBA. As an alternative or in addition to this, the release is issued by SK DE (user of the system. Swiss Krono Germany, specifically SWISS KRONO TEX GmbH & Co, KG) if both previous tests have been positive. A possible parameter that can be determined during the incoming inspection is the VOC amount, which the manufacturer can use, for example, through this table Manufacturer article description solvent content % water content % VOC % Density kg/dm3 Blue Staedtler 48ACT4-B1 42% 56% 36% 1,055 Red Staedtler 48ACT4-R1 30% 63% 24% 1,058 Yellow Staedtler 48ACT4-Y1 37% 59% 31% 1,062 Black Staedtler 48ACT4-K1 36% 60% 31% 1,058 is predetermined.

Alternatively, other printing inks, for example a red and a different-colored pigment or a red and/or a yellow printing ink with at least one, preferably several, different-colored pigments can be used. Depending on requirements, an ink change can also be carried out, for example with different types of yellow.

Additionally or alternatively, the primer or reaction primer to be used is subjected to an entry control. This can also be done using the ACMS system, for example by applying the primer to a base paper and then carrying out a color measurement. Other parameters that can be used for an incoming inspection are the viscosity, the pH value, the maximum shelf life, the pot life, a color value and/or degree of whiteness, preferably determined with the ACMS system and/or the recipe. The latter in particular if the primer itself is mixed with water and stirred. Then the amount, water quality and/or the amount of VC can be determined.

A cleaning agent that is used is preferably subjected to an incoming inspection, whereby, for example, the parameters in the following table Manufacturer item description solvent content % water content % VOC % Density kg/dm3 Cleaner Staedtler Cleaning 48R4SK20 5% 95% 5% 1.008 Cleaner Staedtler Plate 48PFK20 25% 75% 25% 1.005 Cleaner Staedtler Capping 48CFK20 62% 38% 50% 1.07 Cleaner Staedtler Wash 48ACTWF4K1 37% 63% 30% 0.98 can be used.

The packaging material to be used is preferably subjected to an incoming inspection. This applies to wrapping paper, preferably peripheral packaging with a waterproof PP coating, a front cover with or without a waterproof PP coating, labels that preferably have a machine-readable barcode or QR code and preferably enable a link to SAP, and empty tubes of all widths, plugs , foils for a first packaging and/or an edge protection and/or an adhesive tape.

The decor to be printed is also prepared. For this purpose, digital data is initially provided that was generated by the company itself or provided by a third party. They are preferably created using DTP data creation, for example as vector graphics, Photoshop drawings or similar, and/or generated via an electronic source, such as a photo camera, a film camera, a mobile phone and/or a drone.

The decors can have wood or fantasy decors, the variety of planks that can be produced is unlimited due to the digital printing used. A profile is then created, preferably using the ACMS system, with a decor selection and a digital prototype creation taking place. The decors produced later in production are compared with this master sample and discarded if necessary. This can be done automatically or conventionally, ie in particular manually. If it is found that the decor produced is not sufficient If it matches the original pattern, the applied amount of ink and/or amount of primer can be set and adjusted.

As an alternative or in addition to this, an unpatterned decor can also be sampled. For this purpose, a pattern decoration is provided by a third party, for example. Then the profiling and banding for the substrate and the machine parameters are carried out. The desired decors are then roughly preset in the DTP programs and made available in paper form in digital form (preferably PDF) in different color variations by the responsible media designers. Several of these are put together on a collection sheet, with a maximum of 6 to 7 color gradations being displayed side by side on a paper web width. This is preferably done by a media operator. During production, the decors are described by software, preferably Colorgate software. The data (pdf) profiled in this way is then passed on to the printing machine and ripped by the printer software, after which the proof is printed at least three times after the end of the job or when changing jobs.

In the case of samples without production, the sample sections are not printed at the beginning or end of the roll, but are produced purely as a sample. Normally, the entire width of the paper is always used for this and the decor is printed out in full and the pattern for pressing/patterning is always cut out in the same place. By using digital printing, it is possible to print only the necessary sections for pressing and this in several color gradations. This saves paper, ink and cutting time. In addition, patterns can be printed with minimal paper width in order to save costs. Digital printing systems can also be operated with small paper widths (e.g. system width 2250 mm and production 1200 mm). This allows savings in paper, primer, ink, energy and handling.

The sample web is then clipped and separated and then compared with the original sample in a light booth using standard light D65. Alternatively, a standardized manual impregnation and pressing can be compared with the pressed master sample in the light booth with D65 light. First of all, there is preferably a master master sample in pressed and/or unpressed form, which was produced by a third party and approved by a product manager, measurements being carried out with the ACMS system if necessary. The actual original sample is created on this basis, which is also available in pressed and/or unpressed form and can be used for quality control of production orders. A current production is preferably compared with an earlier, preferably the previous, production and/or the original sample. The original sample is preferably created digitally as a separate print job, adjusted via ACMS and then stored for quality control.

After the incoming inspection and the preparation of the decor, the actual production planning takes place. A minimum quantity of approx. 500 m2 should be printed for a decor to be printed. A roller with a diameter of at least 300mm should be used for impregnation.

The types of paper to be used must be kept available and preconditioned in the quantities required. The same applies to the primer, which must be kept available in the application quantity and with the required anilox roller. If necessary, the width of the production line is adjusted between 1300 mm and 2070 mm. In addition, the decor sequence and the print use on the roll must be specified with regard to the color intensity, the customer, the quantity and/or the type of paper. The use of digital printing means that there are no set-up times when changing decor, provided that the data import and the decor composition have been carried out beforehand by a media operator or machine operator. Even with a paper change, there is preferably no loss of time if this is done fully automatically via a roll change.

With these parameters, a reject rate of less than 1% is possible and the system can be operated in 2, 3 or 4 shifts at least almost around the clock. Preferred production parameters are a hall temperature of approx. 23°C with a relative humidity of approx. 55%.

For printing, i.e. the production of the printed decor, the decor is first approached. The decor is preferably adapted to an original pattern using ACMS. This adjustment preferably takes place on the one hand for the paper primed with a primer and on the other hand for the paper printed with the primer and the printing ink. The production release takes place again after a test with ACMS and a comparison with target values.

For production, the delivered roll is first unpacked in an unpacking station and then fed via a turntable to an automatic roll feed and from there to an automatic roll changer. Depending on the width of the paper web used, the printing system adjusts the web width to match the width of the paper web. A paper web cleaning system ensures that there is no dirt on the paper web that could affect the printing result. The temperature of the paper web is measured and monitored regularly, preferably continuously, and adjusted if necessary. The paper web can be tempered for this purpose.

An infeed unit pulls the paper web into the printing system. The feed, in particular the feed speed and the feed force, can be regulated at the edges of the paper web and/or the middle of the web. The infeed is regulated and/or controlled in such a way that paper folds do not form as far as possible. The formation of paper folds is preferably monitored, for example with a 2D and/or 3D laser system. In addition, a paper web guiding system, which guides the paper web through the printing system, can be controlled in this way.

Within the printing system, the paper is fed to a precoating unit, in which a primer is applied. The printing parameters that can be used as control parameters in this unit are, in particular, the applied amount and the VOC amount. The temperature of the primer can also be monitored and the temperature of the primer can be adjusted if necessary. The amount of primer applied is preferably determined via an application control system and compared with target values. A system with near-infrared radiation can be used for this purpose, for example. The viscosity of the primer can also be determined and monitored. With change the viscosity of the primer changes the amount applied and the color behavior. This allows you to set the required amount of primer and the respective amounts of ink and thus the total material costs.

The applied primer is then dried. This can also be done by means of near-infrared radiation or by means of air. If necessary, there is an application inspection system for the primer before and/or after drying, which checks the application quantity, for example with a system based on near-infrared radiation or an L-value control. In particular, light and/or dark spots can be determined using a camera.

The actual digital printing then takes place within at least one digital printing unit. This can, for example, have Inkjet Fuji Samba print heads, preferably in a double row. The printing speed is preferably between 80 and 270 m/min. The decor is preferably applied with a resolution of, for example, 1200×1200 dpi at a printing speed of 135 m/min and of 1200×600 dpi at a speed of 270 m/min. Preferably 4 to 5 different colors are applied. The applied printing ink is then preferably dried in a drying system, preferably using near-infrared radiation or air. The color density is adjusted in a banding compensation system.

This is followed by a quality control, which is preferably carried out online. In this way, a KBA/AVT inspection can be carried out over the entire print width. In the case of the paper printed with primer and printing ink, the color fidelity, nozzle errors, base paper errors, ink splashes and the like are preferably determined. The amount of ink applied and the amount of VOC can also be determined or calculated from the amount of ink applied and the known amount of ingredients. A line of sight can be provided for a visual check.

The quality control can preferably also be carried out after individual process steps, in particular after individual printing units in which individual colors or primers have been applied. In particular, the humidity of the respective printed or to be printed surface is determined at these points, from which operating parameters for dryers are then determined. Changes in length and width are monitored during printing and can be corrected. The paper becomes longer due to the paper tension during the printing process and shrinks in width, this is intensified by the drying process. With digital printing, it is possible to monitor and evaluate this with camera systems, for example, and to correct it by sending information to the machine control. This is particularly advantageous for synchronized products for furniture and laminate flooring with back calculation to press plates. In addition, a change in the paper color due to drying can be detected and used to control the printing system, in particular its dryer. If the dryers are operated too hot, the paper, which is actually white, becomes darker and the color/decor changes as a result. This can be checked with color measuring devices and the dryers can be adjusted in this way.

After quality control, the printed paper web is fed to a roll winder, which preferably has an automatic labeling system. In particular, a tail part of the roll is impregnated with a protective material forming an overwrap of the roll. A pre-run and a post-run in decor printing is required for the start and end of impregnation, but need not be printed with the decor. With digital printing it is possible to implement this. It can be advantageous not to apply primer in these areas of the roll to be printed.

After the paper web has been rolled up, the roll is preferably automatically removed in a roll removal station. Optionally, another sample can be taken and the print image of the current production can be checked with an ACMS measurement. Here, too, the current production can be compared with an earlier production, preferably the previous production and the original sample. The same applies to a quality control of the current production, in which a roller row pressing is carried out and compared with corresponding hand-impregnated and pressed sections of the original sample. The removal preferably takes place at the beginning of the respective paper roll or in the previous roll if this belongs to the same batch of base paper. The production hall is preferably air-conditioned automatically.

After the print job has been produced, it is shut down or switched to a different decor. These can, but do not have to, be printed on a single web of paper from a single roll of paper. Such a role is called a rain floor role.

After the production comes the post-processing. Reserved samples from production are retained in order to be able to prove the delivered quality at a later point in time. A quality report is preferably prepared for the decor, which preferably contains the ACMS logs prepared and the quantity produced. In addition, a section of the original sample and the same section of a manufactured sample can be read into the ACMS and compared. A similarity index in % is given, which is preferably determined by the customer and differs from decor to decor. A certificate can then be created, for example, with an L-value deviation (brightness), an a-value deviation (red-green) and/or a b-value deviation (yellow-blue).

Finally, the roll with the printed paper web is automatically or manually packed, labeled and rewound semi-automatically or fully automatically. It is then stored and, if necessary, commissioned for transport. It is then booked out and transported to the customer. The production parameters and recipes of the respective decor are saved and stored for subsequent orders.

preparation

• ▪ Weiss
  • Menge Anteil ca. 70 %
  • Grammatur (Flächengewicht [g/m²])
  • Glätte nach Bekk [s]
  • Porosität nach Gurley [s/100 mL]
  • Bruchlast [N/15mm] (nass und trocken)
  • Nassdehnung nach Mütek [%] (längs und quer)
  • pH-Wert
  • Aschegehalt [%]
  • Farbwert mit ACMS
  • Weissgrad mit ACMS
  • (Nassreißfestigkeit)
  • Die Wareneingangskontrollen gelten für alle Papiersorten
  • Feuchtemessung (Eingangsfeuchte, Lagerfeuchte, Bereitstellfeuchte)
  • Akklimatisierung der Rolle (Temperatur Außenteil/Kern der Rolle, Berücksichtigung Sommer/Winterbetrieb)
• ▪ Creme Anteil ca. 10 %
  •
• ▪ Hellbeige
  • Menge Anteil ca. 5 %
  • Grammatur
  • Farbwert mit ACMS
  • Weissgrad mit ACMS
  • Nassreißfestigkeit
• ▪ Beige. Anteil ca. 5 %
• ▪ Braun. Anteil ca. 5 %
• ▪ Grau. Anteil ca. 5 %

Rollen bis 125cm Durchmesser / 1,5 to
Kern 3" oder 6"
Breiten 1300 - 2070mm
Grammaturen 50-75g
Dekorpapier oder Idee Frank Vorimprägnat
Restfeuchte ca. 3%
Wareneingangskontrolle evtl. mit ACMS (Frank Punkt 1) Ggf. weitere Lieferanten
∘ Digitaldrucktinte
▪ CRYK von Staedtler (wasserbasiert Inkjet)
• Freigabe jeder einzelnen Charge
∘ von Staedtler an Hand einer geheimen Rezeptur (Staedtler Know how)
∘ von KBA an Hand einer Kleinstprobe, die Staedtler direkt an KBA sendet
∘ von SK DE erst, wenn beide OK eingegangen sind (hierbei wurde im Moment noch nicht festgelegt, welche Parameter von uns geprüft werden können/müssen; Standard wäre: pH-Wert, Farbe, Viskosität etc.)
∘ Menge VC Hersteller Artikelbezeichnung Lösemittelanteil % Wasseranteil % VOC % Dichte kg/dm3 Blau Staedtler 48ACT4-B1 42% 56% 36% 1,055 Rot Staedtler 48ACT4-R1 30% 63% 24% 1,058 Gelb Staedtler 48ACT4-Y1 37% 59% 31% 1,062 Schwarz Staedtler 48ACT4-K1 36% 60% 31% 1,058 ▪ Idee: rot mit weiterem Farbpigment (KRO259 FOL)
▪ Idee: rot und/oder gelb mit einem oder mehreren weiteren Farbpigmenten (KRO265 SDI)
▪ Tintenwechsel der Gelbsorten je nach Bedarf von PY150 auf PY181
o ReaktionsPrimer von Staedtler (auch hier wurden noch keine Parameter festgelegt)
Wareneingangskontrolle evtl. mit ACMS - Auftrag auf Rohpapier und vergleich mit Werten Eingangskontrolle Rohppaier (Frank Punkt 2)

• ▪ Viskosität
• ▪ pH-Wert
• Maximale Lagerfähigkeit
• ▪ Topfzeit
• ▪ Farbwert mit ACMS
• ▪ Weissgrad mit ACMS
• ▪ Rezeptur, falls selbst mit Wasser aufgemischt wird
  • Menge
  • Wassergüte
  • Menge VC

∘ Reiniger von Staedtler Hersteller Artikelbezeichnung Lösemittelanteil % Wasseranteil % VOC % Dichte kg/dm3 Reiniger Staedtler Cleaning 48R45K20 5% 95% 5% 1,008 Reiniger Staedtler Plate 48PFK20 25% 75% 25% 1,005 Reiniger Staedtler Capping 48CFK20 62% 38% 50% 1,07 Reiniger Staedtler Wash 48ACTWF4K1 37% 63% 30% 0,98 ∘ Verpackungsmaterial

• ▪ Umhüllungspapier Umfangsverpackung mit wasserdichter PP-Beschichtung
• ▪ Stirndeckel mit oder ohne wasserdichter PP-Beschichtung
• ▪ Beschriftungsetiketten
  (elektronisch lesbaren Barcode, Verknüpfung SAP)
• ▪ Leerhülsen (alle Breiten)/ Propfen
• ▪ Folie zum ersten einpacken
• ▪ Kantschutzband und Klebeband

• Dekor

• ∘ Digitale Daten
  • ▪ Selbst erzeugt durch Scannen und Anpassen
  • ▪ DTP-Datenerstellung (Vektor-Grafiken, Photoshop-Zeichnung, ... )
  • ▪ elektronische Quellen wie Fotoapparat, Filmkamera, Drohne, Handy, ...
  • ▪ Datensatz eines Dritten
• ∘ Profilieren und Mustern
  • ▪ Profilerstellung mit ACMS (KRO266 EP)
    Dekorausmusterung und digitale Urmusterstellung mit ACMS (KRO266 EP)
    Korrektur während Produktion mit ACMS - zurück zum digitalen Urmuster (KRO266 EP)
  • ▪ Manuelles/herkömmliches ausmustern
• ∘ Holzdekore/Fantasiedekore
• ∘ Dielenvielfalt Digitaldruck unbegrenzt
• ∘ Tintenauftragsmenge beim Ausmustern Regulierung Tinten + Primermenge = Kostenbewertung (Frank Punkt 21)
• ∘ Anmustern ungemusterter Dekore zur Aufsichtsvorlage (z. B.: Muster-Diele, -Ausdruck vom Kunden, Papier, ...) als Prozess, Erweiterung der Idee von 2014 auf den neuen Digitaldruck-Prozess
  • ▪ Voraussetzung: die Profilierung und das Banding zum Bedruckstoff
    und zu den Maschineparameter wurde ausgeführt
  • ▪ Dekore werden in den DTP-Programmen (Photoshop, Illustrator, ... )
    grob voreingestellt
  • ▪ Dekore werden papierbezogen von allen Mediengestaltern in digitaler Form (PDF) in Farbabwandlungen bereitgestellt
  • ▪ der Medien-Operator stellt einen Sammelbogen zusammen (z.B.: 6 bis max. 7 Farbabstufungen auf Papierbahnbreite)
  • ▪ während der laufenden Produktion durch die Colorgate-Software mit dem aktuellen Profil beschrieben
  • ▪ die profilierten Daten (PDF) werden an Druckmaschine weitergegeben und
    durch die Drucker-Software gerippt
  • ▪ der Andruck erfolgt nach Auftrags-Ende bzw. zum Auftragswechsel
    zu mindestens 3 Wiederholungen
  • ▪ Musterungsbahn wird geklippt und separiert
  • ▪ Musterungsvergleich bei Standard-Licht D65 in der Lichtkabine
  • ▪ oder - standardisierte Handimprägnierung und Verpressung zum Vergleich
    mit verpressten Urmustern in Lichtkabine bei D65
• ∘ Ur-Urmuster verpresst/unverpresst
  • ▪ Selbst erzeugt und durch Produktmanager freigegeben
  • ▪ Von einem Dritten erzeugt und durch Produktmanager/ggf. ACMS freigegeben
• ∘ Urmuster verpresst/unverpresst
  • ▪ Zur Qualitätskontrolle von Produktionsaufträgen durch Vergleich (aktuelle Produktion, Urmuster und letzte Produktion)
  • ▪ Idee: Urmuster als eigenen Druckauftrag digital erstellen, über ACMS anpassen und dann für die Qualitätskontrolle bevorraten
• ∘ Muss zwischen Vorbereitung und Produktion eingeordnet werden: Festlegung des Similarity-Index (ACSM) in Zusammenarbeit SK Heiligengrabe mit jeweiligen Kunden

• Produktionsplanung

• ∘ Mindestmenge pro Dekor ca. 500m2
  bzw. für Imprägnierung mind. 300mm Rollendurchmesser 300mm Rollendurchmesser
• ∘ Vorhaltung / Vorkonditionierung Papiersorten und Menge
• ∘ Rasterwalze / Primerauftragsmenge
• ∘ Ggf. Breiteneinstellungen der Produktionsanlage 1300-2070mm
• ∘ Dekorfolge/Drucknutzen auf Rolle im Hinblick auf Farbintensität, Kunde, Menge, Papiersorte festlegen
• ∘ Rüstzeit bei Dekorwechsel keine
  (vorangestellte Rüstzeit: Daten-Import, Dekorzusammenstellung durch Medien-Oparatur bzw. Maschinenbediener)
• ∘ Papierwechsel vollautomatisch über autom. Rollenwechsler - kein Zeitverlust
• ∘ geplanter Ausschuss in % <1%
• ∘ Schichtbetrieb 2-4 Schichtbetrieb
• ∘ Regenbogenrolle
• ∘ Parameter = Hallenklima 23°C bei 55% rel. Luftfeuchte / Produktionsparameter

• Goods receipt with entry control
o Paper as the substrate

• ▪ White
  • Amount Proportion approx. 70%
  • Grammage (weight per unit area [g/m ² ])
  • Smoothness according to Bekk [s]
  • Gurley porosity [s/100 mL]
  • Breaking load [N/15mm] (wet and dry)
  • Wet elongation according to Mütek [%] (longitudinal and transverse)
  • PH value
  • Ash content [%]
  • Color value with ACMS
  • Whiteness with ACMS
  • (wet tensile strength)
  • The incoming goods inspections apply to all types of paper
  • Moisture measurement (input moisture, storage moisture, ready moisture)
  • Acclimatization of the roll (temperature of the outer part/core of the roll, taking into account summer/winter operation)
• ▪ Cream content approx. 10%
  •
• ▪ Light beige
  • Amount Proportion approx. 5%
  • grammage
  • Color value with ACMS
  • Whiteness with ACMS
  • wet tensile strength
• ▪ Beige. Share approx. 5%
• ▪ Brown. Share approx. 5%
• ▪ Gray. Share approx. 5%

Rolls up to 125cm in diameter / 1.5 to
Core 3" or 6"
Widths 1300 - 2070mm
Grammages 50-75g
Decor paper or Idea Frank pre-impregnated
Residual moisture approx. 3%
Incoming goods inspection possibly with ACMS (Frank Point 1) Possibly other suppliers
∘ Digital printing ink
▪ CRYK from Staedtler (water-based inkjet)
• Approval of each individual batch
∘ from Staedtler using a secret recipe (Staedtler know-how)
∘ from KBA based on a small sample that Staedtler sends directly to KBA
∘ from SK DE only when both OKs have been received (at the moment it has not yet been determined which parameters can/must be checked by us; standard would be: pH value, color, viscosity, etc.)
∘ Amount of VC Manufacturer item description solvent content % water content % VOC % Density kg/dm3 Blue Staedtler 48ACT4-B1 42% 56% 36% 1.055 Red Staedtler 48ACT4-R1 30% 63% 24% 1,058 Yellow Staedtler 48ACT4-Y1 37% 59% 31% 1,062 Black Staedtler 48ACT4-K1 36% 60% 31% 1,058 ▪ Idea: red with additional color pigment (KRO259 FOL)
▪ Idea: red and/or yellow with one or more additional color pigments (KRO265 SDI)
▪ Changing the yellow types of ink from PY150 to PY181 as required
o Staedtler reaction primer (no parameters have been defined here either)
Incoming goods inspection possibly with ACMS - order on raw paper and comparison with values incoming inspection raw paper (Frank point 2)

• ▪ Viscosity
• ▪ pH value
• Maximum shelf life
• ▪ Pot life
• ▪ Color value with ACMS
• ▪ Whiteness with ACMS
• ▪ Recipe if you mix with water yourself
  • Crowd
  • water quality
  • amount of VC

∘ Cleaner from Staedtler Manufacturer item description solvent content % water content % VOC % Density kg/dm3 Cleaner Staedtler Cleaning 48R45K20 5% 95% 5% 1.008 Cleaner Staedtler Plate 48PFK20 25% 75% 25% 1.005 Cleaner Staedtler Capping 48CFK20 62% 38% 50% 1.07 Cleaner Staedtler Wash 48ACTWF4K1 37% 63% 30% 0.98 ∘ Packaging material

• ▪ Wrapping paper perimeter packaging with waterproof PP coating
• ▪ Front cover with or without waterproof PP coating
• ▪ Writing labels
  (electronically readable barcode, link SAP)
• ▪ Empty tubes (all widths)/plugs
• ▪ Pack the foil first
• ▪ Corner protection tape and adhesive tape

• Decor

• ∘ Digital data
  • ▪ Self-generated by scanning and adjusting
  • ▪ DTP data creation (vector graphics, Photoshop drawing, ... )
  • ▪ Electronic sources such as cameras, film cameras, drones, mobile phones, ...
  • ▪ Third party record
• ∘ Profiling and patterns
  • ▪ Profiling with ACMS (KRO266 EP)
    Decor selection and digital prototype creation with ACMS (KRO266 EP)
    Correction during production with ACMS - back to the digital master pattern (KRO266 EP)
  • ▪ Manual/conventional scrapping
• ∘ Wood decors/fantasy decors
• ∘ Board variety digital printing unlimited
• ∘ Ink application quantity when discarding adjustment inks + primer quantity = cost evaluation (Frank point 21)
• ∘ Sampling of unpatterned decors for the template (e.g. sample plank, printout from the customer, paper, ...) as a process, extension of the idea from 2014 to the new digital printing process
  • ▪ Requirement: profiling and banding to the substrate
    and to the machine parameters was executed
  • ▪ Decors are created in the DTP programs (Photoshop, Illustrator, ... )
    roughly preset
  • ▪ Paper-related decors are provided by all media designers in digital form (PDF) in color variations
  • ▪ the media operator puts together a collection sheet (e.g.: 6 to max. 7 color gradations on the width of the paper web)
  • ▪ written with the current profile by the Colorgate software during ongoing production
  • ▪ the profiled data (PDF) are passed on to the printing machine and
    ripped by the printer software
  • ▪ the print is made after the end of the job or when changing jobs
    for at least 3 repetitions
  • ▪ Pattern track is clipped and separated
  • ▪ Pattern comparison with standard light D65 in the light booth
  • ▪ or - standardized manual impregnation and pressing for comparison
    with pressed original samples in the light booth at D65
• ∘ Original prototype pressed/unpressed
  • ▪ Self-generated and approved by the product manager
  • ▪ Generated by a third party and tested by product managers/possibly ACMS released
• ∘ Master sample pressed/unpressed
  • ▪ For quality control of production orders by comparison (current production, original sample and last production)
  • ▪ Idea: create original samples digitally as your own print job, adapt them via ACMS and then store them for quality control
• ∘ Must be classified between preparation and production: Determination of the similarity index (ACSM) in cooperation with SK Heiligengrabe and the respective customer

• Production planning

• ∘ Minimum quantity per decor approx. 500m2
  or for impregnation min. 300mm roll diameter 300mm roll diameter
• ∘ Provision / preconditioning of paper types and quantity
• ∘ Anilox roller / amount of primer applied
• ∘ If necessary, width settings of the production system 1300-2070mm
• ∘ Specify decor sequence/printing on the roll with regard to color intensity, customer, quantity, paper type
• ∘ No set-up time when changing decor
  (Preset setup time: data import, decor composition by media repair or machine operator)
• ∘ Paper change fully automatic via autom. Reel changer - no loss of time
• ∘ Planned waste in % <1%
• ∘ Shift work 2-4 shift work
• ∘ Rainbow roll
• ∘ Parameter = indoor climate 23°C at 55% rel. Humidity / production parameters

To press

• • Approaching a decor
  • ∘ Adaptation to a master pattern of this decor with ACMS
    • ▪ Paper with primer
    • ▪ Paper with primer and digital printing ink
  • ∘ Production release with ACMS
• • To produce
  • ∘ Unpacking station
  • ∘ Turntable
  • ∘ Automatic roll feed
  • ∘ Automatic splicer
  • ∘ Web width adjustment
  • ∘ Paper web cleaning system
  • ∘ Paper temperature monitoring (Frank Point 5)
  • ∘ Possibly paper temperature control (Frank point 29)
  • ∘ Web threading device with infeed unit ∘ Web edge and center control
  • ∘ Paper wrinkling Monitoring and appropriate control if necessary
    • ▪ 2D/D3 laser monitoring, company Micro Epsilon
  • ∘ Paper web guiding system
  • ∘ Inline precoating unit primers
    • ▪ Quantity
    • ▪ VC
      Primer Temperature Monitor (Frank Point 5)
      Possibly primer temperature control (Frank point 30)
      Controlling viscosity over time is possible and beneficial, but not necessary.
      Application Control System Primer - NIR or similar (Frank Point 14)
  • ∘ Drying system for primer NIR/air
  • ∘ Possibly application inspection system for primer - NIR control system or L-value control (light-dark spots with camera) (Caution: Relationship between application quantity and open porosity of the paper Possibly contact angle measurements)
  • ∘ Digital printing unit
    • ▪ Inkjet Fuji Samba printheads double row
    • ▪ 80 - 270m/min
      (e.g. 1200x1200dpi at 135m/min. or 1200x600dpi/min. 270m/min.)
    • ▪ 4-5 colors (possibly 2 yellow)
  • ∘ Drying system for NIR/air digital printing
  • ∘ Banding Compensation System (color density adjustment)
  • ∘ Inline quality control with KBA/AVT inspection over the entire print width
    Inline control and preferably also control with I-ACMS
    ▪ Paper with primer and digital printing ink
    • Color fidelity and nozzle errors / base paper errors / spatter etc.
    • Crowd
    • VC possibly with software > order quantity/ingredients = VOC quantity
  • ∘ Line of sight for visual control
  • ∘ Automatic labeling system for roll rewinder ∘ Automatic rewind station
  • ∘ Automatic roll removal station
  • ∘ Optional sample of current production with ACMS > 1x per roll required for certificate
    • ▪ Current production
    • ▪ Original pattern
    • ▪ Last production
  • ∘ Quality control of the current production (roller row pressing)
    Original sample <> current production <> last production Corresponding original sample excerpts, hand impregnation and pressing
    (Pickup at the beginning or in the previous roll if paper of the same lot)
  • ∘ Fully automated hall air conditioning
    • Depart or change to another decor
    • How do you approach when rainbow rolls are to be produced? Decors are created with the appropriate order quantity as a print job and printed one after the other. The patterns for ACMS are either at the beginning of the role
      created or already in the previous rolls if the same paper of a batch can be printed. This can only be the pattern sections that have been specially placed.
      (Principle of the idea of prototype production)

postprocessing

• reserve sample from production
• quality report
  • ∘ Decor
  • ∘ ACMS protocol
  • ∘ Quantity
• ACMS
  Production of prototype (detail)
  Manufacturing sample production (same excerpt)
  Both import ACMS
  Output Deviation similarity index in % → must be determined with the customer, varies from decor to decor
  Certificate e.g. with L value deviation (brightness) a value deviation (red-green) b value deviation (yellow-blue)
• Packaging manually on the reel / fully automatic packaging machine
• labeling
• Rewinding semi-automatically in the printing system / fully automatic rewinder
• Store manually/fully automatically
• Transport order (bundle if necessary)
• derecognition
• Transport to customers
• expense report
• Manage production parameters/recipes from decor (store machine parameters in the machine for subsequent orders, automated)

Other aspects are:

1. 1. A lead and a lag in decor printing is required for the start and end of impregnation, but does not need to be printed with the decor. With digital printing it is possible to implement this. Whether primer can also be omitted must be checked and should be listed as an option. Since considerable cost savings are possible here, we will include this for the start of production and discuss it with our customers.
2. 2. In the case of samples without production, the sample sections are not printed at the beginning or end of the roll, but are produced purely as a sample. Normally, the entire width of the paper is always used for this and the decor is printed out in full and the pattern for pressing/patterning is always cut out in the same place. This is not possible any other way with gravure printing. With digital printing, on the other hand, we only print the necessary cut-outs for pressing and we do this in several color gradations, thus saving paper and ink as well as time when cutting out.
3. 3. Monitor and correct changes in length and width during printing: Paper becomes longer due to the paper tension during the printing process and shrinks in width, this is increased by drying. With digital printing it will be possible in the future to monitor and evaluate this with the new camera systems and through information to the machine control to be corrected. In particular for synchronous products for furniture and laminate flooring with back calculation to press plates.
4. 4. Samples with minimal paper width to save costs: Digital printing systems can also be operated with smaller paper widths (e.g. system width 2250 mm and production 1200 mm possible). This allows savings in paper, primer, ink, energy and handling.
5. 5. Detection and control of change in paper color due to drying:
   If the dryers are operated too hot, the paper, which is actually white, becomes darker and the color/decor changes as a result. This can be checked with color measuring devices and the dryers can be adjusted in this way.
6. 6. Changing the viscosity of the primer changes the amount applied and the color behavior. This allows you to optimally adjust primer and ink quantities and thus the total material costs. This is probably closely related to the absorption behavior of the paper and the leveling properties + reactivity of the primer. The temperature change of paper and primer has not yet been tested. There is still potential for optimization here.

Claims (8)

Method for printing a surface of a base paper with a decoration using a digital printing system, the method having the following steps: a. Providing a raw paper whose surface is to be printed, b. applying a primer to the surface of the base paper, c. drying the applied primer in a first dryer, i.e. Printing the decor onto the dried primer using a printing unit of the digital printing system, and e. drying of the printed base paper in a second dryer, characterized in that
a room in which the method is carried out is ventilated and air-conditioned in such a way that the room has a homogeneous relative humidity. Method according to claim 1, characterized in that the relative humidity is between 40% and 45%. Method according to Claim 1 or 2, characterized in that the space is ventilated and air-conditioned in such a way that the air temperature in the space is homogeneous. Method according to one of the preceding claims, characterized in that the digital printing system is ventilated and air-conditioned in such a way that the relative humidity and/or the air temperature prevails in it. Method according to one of the preceding claims, characterized in that the first drier and/or the second drier dries at a heating temperature of 155°C to 250°C. Method according to one of the preceding claims, characterized in that no markings along which the paper is cut are printed. Method according to one of the preceding claims, characterized in that the printed paper is impregnated. Method according to one of the preceding claims, characterized in that the base paper has a grammage of 35 g to 58 g.