DE102018130281A1 - Sheet printing machine with at least one printing unit for printing printed sheets - Google Patents

Abstract

The invention relates to a sheet-fed printing machine with at least one printing unit for printing printed sheets, a drying unit being provided in or after the at least one printing unit in the transport path, printing sheets printed by the at least one printing unit being guided or at least feasible through a chamber of this drying unit, an atmosphere reduced by an inert gas being provided in the chamber of the drying unit. The drying unit has an electron beam generator for drying the printed printed sheets by means of an electron beam directed into the chamber, the atmosphere in the chamber of the drying unit having an oxygen content of at most 1%.

Description

The invention relates to a sheet-fed printing machine with at least one printing unit for printing printed sheets, according to the preamble of claim 1.

Through the WO 2005/097927 A1 a method for printing is known in which an ink is printed using an Intaglio printing machine on a substrate in which the ink is hardened after printing, in which the hardening e.g. B. done by an electron beam. This method is e.g. B. used for the production of banknotes.

1. a) Aufbringen einer ersten Schicht auf das Substrat,
2. b) Aufbringen von zumindest einer zweiten Schicht auf die erste Schicht, wobei vor dem Aufbringen der zweiten Schicht keine vollständige Härtung der ersten Schicht erfolgt,
3. c) Prägen von zumindest einer Schicht der Beschichtung,
4. d) Härten der Beschichtung,

wobei das Aufbringen der Schichten z. B. durch ein Druckverfahren, insbesondere Tiefdruck, Flexodruck oder Offsetdruck erfolgt, wobei das Härten der Schichten z. B. durch ultraviolette Strahlung und/oder durch Elektronenstrahlung erfolgt.Through the DE 10 2006 032 679 A1 A method for producing a security element for a security paper, security document or the like with a substrate is known, wherein the substrate is at least partially equipped with a coating comprising at least two layers, with the steps

1. a) applying a first layer to the substrate,
2. b) applying at least one second layer to the first layer, the first layer not being fully hardened before the second layer is applied,
3. c) embossing at least one layer of the coating,
4. d) hardening of the coating,

the application of the layers e.g. B. is carried out by a printing process, in particular gravure, flexographic or offset printing, the hardening of the layers z. B. by ultraviolet radiation and / or by electron radiation.

Through the DE 10 2016 200 544 A1 A device for treating sheet-shaped substrate is known, with a sheet guide cylinder and an inerting device assigned to the sheet guide cylinder, the sheet guide cylinder having first holding means for holding the front edge of the substrate and second holding means being provided which hold the substrate on the sheet guide cylinder in a region spaced apart from the front edge of the substrate and wherein the substrate guided by the sheet guide cylinder can be acted upon by inert gas, a third holding means being arranged outside the periphery of the sheet guide cylinder.

The invention has for its object to provide a sheet-fed printing machine with at least one printing unit for printing substrates with an improved drying unit, the drying unit being suitable for the highest possible printing speed of the printing machine in an industrial production process.

The object is achieved by the features of claim 1. The dependent claims show advantageous refinements and / or developments of the solution found.

The advantages that can be achieved with the invention are, in particular, that the drying unit of the printing press is suitable for the highest possible printing speed of the printing press in an industrial production process. Further advantages are evident from the exemplary embodiments described.

Exemplary embodiments of the invention are shown in the drawings and are described in more detail below.

• 1 eine Druckmaschine mit mindestens einem Druckwerk;
• 2 eine Trocknungseinheit zur Elektronenstrahlhärtung;
• 3 einen Ausschnitt aus der in der 1 dargestellten Druckmaschine mit einer ersten Anordnung einer Trocknungseinheit zur Elektronenstrahlhärtung im Druckwerk;
• 4 einen Ausschnitt aus der in der 1 dargestellten Druckmaschine mit einer zweiten Anordnung einer Trocknungseinheit zur Elektronenstrahlhärtung im Druckwerk;
• 5 einen Ausschnitt aus der in der 1 dargestellten Druckmaschine mit einer Anordnung einer Trocknungseinheit zur Elektronenstrahlhärtung an einem Zwischenzylinder;
• 6 einen Ausschnitt aus einer Druckmaschine mit einer Anordnung einer Trocknungseinheit zur Elektronenstrahlhärtung an einer Transporteinrichtung;
• 7 eine an einen Saugzylinder angestellte Trocknungseinheit zur Elektronenstrahlhärtung;
• 8 eine Trocknungseinheit zur Elektronenstrahlhärtung in Verbindung mit mehreren Saugwalzen;
• 9 eine als eine eigenständige Baueinheit verwendbare Trocknungseinheit.

Show it:

• 1 a printing press with at least one printing unit;
• 2nd a drying unit for electron beam curing;
• 3rd a section of the in the 1 Printing machine shown with a first arrangement of a drying unit for electron beam curing in the printing unit;
• 4th a section of the in the 1 Printing machine shown with a second arrangement of a drying unit for electron beam curing in the printing unit;
• 5 a section of the in the 1 illustrated printing press with an arrangement of a drying unit for electron beam curing on an intermediate cylinder;
• 6 a section of a printing press with an arrangement of a drying unit for electron beam curing on a transport device;
• 7 a drying unit attached to a suction cylinder for electron beam curing;
• 8th a drying unit for electron beam curing in connection with several suction rolls;
• 9 a drying unit that can be used as an independent structural unit.

1 shows an example of a printing press, preferably a rotary printing press, each with at least one printing unit. The printing machine is e.g. B. designed as a sheet-fed printing press, preferably as a sheet-fed rotary printing press, in particular as a sheet-fed printing press, very particularly as a sheet-fed rotary printing press that prints in an intaglio printing process. The intaglio printing process is a gravure printing process, which is preferably used for the industrial production of banknotes, security documents or security elements.

1. a) einen Bogenanleger 01, mittels welchem ein zu bedruckendes Substrat 21 in Form von insbesondere gestapelten Druckbogen 21 an der Bogenrotationsdruckmaschine bereitgestellt wird oder zumindest bereitstellbar ist; die rechteckigen Druckbogen 21 haben z. B. ein Kantenmaß im Bereich zwischen 475 × 450 mm und 700 × 820 mm; die Grammatur der Druckbogen 21 liegt z. B. im Bereich zwischen 70 g/m² und 120 g/m²;
2. b) eine Bogenanlage 02, mittels welcher am Bogenanleger 01 bereitgestellte Druckbogen 21 z. B. über eine oder mehrere Transfertrommeln einem Druckwerk 03 der Bogenrotationsdruckmaschine in einer Sequenz, d. h. einzeln nacheinander zugeführt werden oder zumindest zuführbar sind;
3. c) mindestens ein Druckwerk 03, aufweisend einen auch als Gegendruckzylinder bezeichneten Druckzylinder 04 und einen mit dem Druckzylinder 04 zusammenwirkenden ein Druckbild auf die betreffenden Druckbogen 21 auftragenden Plattenzylinder 06, wobei der Druckzylinder 04 und Plattenzylinder 06 unter hohem Druck gegeneinander angestellt oder zumindest anstellbar sind; ein Wischzylinder 07 ist gegen den Plattenzylinder 06 angestellt oder zumindest anstellbar; der Druckzylinder 04 und Plattenzylinder 06 sind vorzugsweise aus Stahl gefertigt; der Wischzylinder 07 ist auf seiner Mantelfläche z. B. mit einem Kunststoff beschichtet; in der bevorzugten Ausführung sind der Druckzylinder 04 und der Plattenzylinder 06 jeweils an ihrem Umfang jeweils in mehrere, insbesondere in drei jeweils gleich große Segmente unterteilt, wobei in jedem der am Druckzylinder 04 hintereinander angeordneten Segmente jeweils z. B. auf einer Unterlage jeweils ein Drucktuch angeordnet oder zumindest anordenbar ist;
4. d) einen an den Plattenzylinder 06 angestellten oder zumindest anstellbaren, auch Orlofzylinder 08 genannten Sammelzylinder 08; der Orlofzylinder 08 weist an seinem Umfang vorzugsweise ebenso wie der Druckzylinder 04 und Plattenzylinder 06 drei gleich große Segmente auf;
5. e) eine Farbwerkseinheit 09, aufweisend mehrere, z. B. fünf oder sechs jeweils an den Orlofzylinder 08 angestellte oder zumindest anstellbare Schablonenzylinder 11, an deren Umfang jeweils eine Schablonenplatte angeordnet oder zumindest anordenbar ist; dabei färbt jeder der Schablonenzylinder 11 den Orlofzylinder 08 vorzugsweise jeweils mit einer anderen Druckfarbe ein, wobei der Orlofzylinder 08 während einer einzigen Umdrehung die jeweilige Druckfarbe von allen angestellten Schablonenzylindern 11 sammelt; an jeden Schablonenzylinder 11 sind eine oder mehrere Farbauftragswalzen 12 angestellt oder zumindest anstellbar, wobei die Farbauftragswalzen 12 jeweils von einem Druckfarbe aus einem Farbreservoir 14, z. B. aus einem Farbkasten entnehmenden Farbduktor 13 eingefärbt werden; die hier beschriebene Bauart der Druckmaschine ermöglicht demnach an einer einzigen Druckstelle ein mehrfarbiges Bedrucken der Druckbogen 21; alternativ oder zusätzlich zur Farbwerkseinheit 09 kann auch ein Lackwerk zum Auftragen eines Lackes auf die jeweiligen Druckbogen 21 vorgesehen sein;
6. f) eine z. B. als ein umlaufendes Transportband oder als ein umlaufendes Kettensystem, insbesondere Kettengreifersystem ausgebildete Transporteinrichtung 16, an welche in einem Druckspalt 17 zwischen dem Druckzylinder 04 und dem Plattenzylinder 06 bedruckte Druckbogen 21 unmittelbar oder über mindestens einen Zwischenzylinder 36; 37 übergeben werden, wobei an die Transporteinrichtung 16 übergebene Druckbogen 21 mittels dieser zu einer z. B. als eine Mehrstapelauslage ausgebildeten Auslage 18, hier Bogenauslage 18, transportiert werden oder zumindest transportierbar sind und dort abgelegt werden oder zumindest ablegbar sind; in der 1 weist die Bogenauslage 18 in Transportrichtung T der Druckbogen 21 z. B. drei hintereinander angeordnete Stapel auf; im Bereich der Transporteinrichtung 16 ist i.d.R. ein z. B. optoelektronisches, vorzugsweise kamerabasiertes Inspektionssystem 19 angeordnet, mittels welchem eine Qualität der bedruckten Druckbogen 21 geprüft wird oder zumindest prüfbar ist; die Druckbogen 21 werden insbesondere auf ihre Fehlerfreiheit im Vergleich mit einer vorgegebenen Vorlage geprüft; in Abhängigkeit von diesem Prüfungsergebnis werden die Druckbogen 21 dann auf einem bestimmten Stapel der Mehrstapelauslage abgelegt.

The in the 1 The sheet-fed rotary printing press shown by way of example, in particular printing in an intaglio printing process, preferably has at least the following machine units or assemblies:

1. a) a sheet feeder 01 , by means of which a substrate to be printed 21st in the form of stacked printed sheets in particular 21st is provided or at least can be provided on the sheet-fed rotary printing press; the rectangular printed sheets 21st have z. B. an edge dimension in the range between 475 × 450 mm and 700 × 820 mm; the grammage of the printed sheets 21st lies z. B. in the range between 70 g / m ² and 120 g / m ² ;
2. b) an arch system 02 , by means of which on the sheet feeder 01 provided printed sheets 21st e.g. B. over one or more transfer drums a printing unit 03 fed to the sheet-fed rotary printing press in one sequence, ie one after the other, or at least can be fed;
3. c) at least one printing unit 03 , comprising a pressure cylinder also referred to as an impression cylinder 04 and one with the impression cylinder 04 interacting a print image on the relevant print sheet 21st brushing plate cylinder 06 , with the impression cylinder 04 and plate cylinder 06 are against each other under high pressure or at least employable; a wiping cylinder 07 is against the plate cylinder 06 employed or at least employable; the impression cylinder 04 and plate cylinder 06 are preferably made of steel; the wiping cylinder 07 is on its outer surface z. B. coated with a plastic; in the preferred embodiment are the impression cylinder 04 and the plate cylinder 06 each divided into several, in particular three, segments of the same size, each in their circumference, in each of which on the pressure cylinder 04 successively arranged segments each z. B. a blanket is arranged or at least can be arranged on a base;
4. d) one on the plate cylinder 06 employed or at least employable, also Orlof cylinders 08 called collecting cylinder 08 ; the Orlof cylinder 08 preferably has on its circumference just like the impression cylinder 04 and plate cylinder 06 three equal segments;
5. e) an inking unit 09 , having several, e.g. B. five or six each to the Orlof cylinder 08 employed or at least employable template cylinders 11 , on the circumference of which a template plate is arranged or at least can be arranged; each of the stencil cylinders colors 11 the Orlof cylinder 08 preferably each with a different printing ink, the orl cylinder 08 the respective printing ink of all employed stencil cylinders during a single revolution 11 collects; on each template cylinder 11 are one or more inking rollers 12 employed or at least employable, the inking rollers 12 each from a printing ink from a color reservoir 14 , e.g. B. from a paint box taking ink duct 13 be colored; The design of the printing machine described here therefore enables multi-color printing of the printed sheets at a single printing point 21st ; alternatively or in addition to the inking unit 09 can also be a coating unit for applying a coating to the respective printing sheet 21st be provided;
6. f) a z. B. as a revolving conveyor belt or as a revolving chain system, in particular chain gripper system designed transport device 16 to which in a pressure nip 17th between the impression cylinder 04 and the plate cylinder 06 printed printed sheets 21st directly or via at least one intermediate cylinder 36 ; 37 be handed over to the transport facility 16 transferred printing sheets 21st by means of this to a z. B. designed as a multi-stack delivery 18th , here sheet display 18th , are transported or are at least transportable and are stored there or at least can be stored; in the 1 shows the sheet display 18th in the direction of transport T the press sheet 21st e.g. B. three consecutive stacks; in the area of the transport facility 16 is usually a z. B. optoelectronic, preferably camera-based inspection system 19th arranged, by means of which a quality of the printed printed sheets 21st is checked or at least can be checked; the printed sheets 21st are checked in particular to ensure that they are free of errors in comparison with a given template; depending on this test result, the printed sheets 21st then placed on a specific stack of the multi-stack delivery.

To achieve the highest possible printing speed of z. B. 10,000 printed sheets 21st to reach per hour, those on the printed sheets 21st applied printing ink and / or on the printing sheet 21st applied varnish preferably dried. Non-running, ie viscous printing inks and / or lacquers are preferably used. In the preferred embodiment, radiation-curing printing inks and / or lacquers are used. In a particularly preferred embodiment, solvent-free printing inks and / or lacquers curable by an electron beam are used. Such printing inks and / or lacquers polymerize when irradiated with an electron beam within milliseconds and are thus dried in an extremely short time. A color film or lacquer film consisting of such printing inks and / or lacquers is completely polymerized and is thus also fully hardened, so that after drying in the printing inks or lacquers, no fragments or cleavage residues remain through the substrate 21st could migrate elsewhere. Printing inks or varnishes dried by an electron beam form an elastic, glossy color film or varnish film, which is highly resistant to scratches and chemicals.

However, a problem with a drying process using an electron beam is that the drying, that is to say the setting reaction, must take place in an oxygen-reduced, inert atmosphere in which the oxygen content is at most 1%, preferably in a range between 300 ppm and 500, in order to achieve high production quality ppm, in particular in the range between 150 ppm and 250 ppm, possibly even lower down to the range of less than 50 ppm, the permissible proportion of oxygen in the inert atmosphere from the material of the substrate used 21st and / or is dependent on the chemical composition of the printing ink (s) or lacquers used. Otherwise, i.e. with a higher oxygen content, free radicals contained in the still liquid printing inks or varnishes, ie atoms or groups of atoms, each containing a free electron, would react more quickly with the oxygen molecules contained in this air than with one another and only incomplete , uneven networking. This is particularly true under normal ambient air with an oxygen content of around 21%. In an atmosphere with an oxygen content of more than 1%, especially under normal ambient air, the setting reaction leads to the printing inks or varnish still being wet, sticky and without gloss, with poor adhesion properties and only poor scratch resistance.

Good drying results are achieved in one drying unit 22 with an atmosphere reduced to an oxygen content of at most 1%, in which an inert, ie a chemically very inert gas, e.g. B. an elementary gas such as nitrogen or a noble gas such as helium, neon, argon, krypton, xenon or radon or a gaseous molecular compound such as sulfur hexafluoride and carbon dioxide displaces the oxygen contained in the air. An inert gas prevents oxidative processes due to the displacement or significant reduction of oxygen. The term “atmosphere” is used here and below - to the extent that it relates to the volume of the drying unit 22 related - holistically refers to the oxygen-reduced gaseous medium in the drying unit 22 in a room intended for drying the printing inks or varnish.

2nd illustrates the principle of radiation drying with an electron beam.

Even if the examples described below primarily relate to the drying of printing inks, they also apply in a corresponding manner to the drying of lacquers. A drying unit that can be used in conjunction with a printing press, in particular with the printing press described above as an example 22 points one from the substrate 21st , e.g. B. the press sheet 21st passed through chamber filled with an inert gas or at least containing an inert gas 23 on, being at the entrance to the chamber 23 on which the printed sheets 21st into the chamber containing the inert gas 23 be introduced, e.g. B. a doctor nozzle 24th is arranged in particular in the form of a nozzle bar to prevent the inert gas from the chamber at this inlet 23 escapes and / or oxygen from the ambient air into this chamber 23 entry. Because of the flatness of the printed sheets 21st is the entrance to the chamber 23 usually as a transversely to the direction of transport T the press sheet 21st formed across its entire width narrow slot. To fill the chamber 23 with the inert gas, e.g. B. with nitrogen, and / or to maintain the desired level is an inert gas if necessary in the chamber 23 admitting, in particular remotely operated filling nozzle 26 provided, this filling nozzle 26 to an inert gas source, e.g. B. is connected to a tank. Furthermore, there is preferably a sensor 27 for measuring the oxygen content in the chamber containing the inert gas 23 intended. The filling nozzle 26 is preferably dependent on a measurement result of the sensor 27 for measuring the oxygen content in the chamber containing the inert gas 23 regarding the admission of inert gas into the chamber 23 controlled or at least controllable. If so in the chamber 23 the drying unit 22 a filling nozzle which is connected to the inert gas source and in particular can be operated remotely 26 and a sensor 27 to measure the in this chamber 23 existing oxygen content are provided, then the oxygen content in the chamber 23 prevailing inert atmosphere advantageously z. B. from a control unit in particular automatically, depending on a measurement result of the sensor 27 for measuring the oxygen content and / or depending on the material of the printed sheets to be dried 21st and / or, depending on the chemical composition, at least one on the printed sheets 21st applied printing ink or varnish adjusted or at least adjustable.

The drying unit 22 has an electron beam generator 28 on which is in a vacuum chamber 29 is arranged. The vacuum chamber 29 and the chamber filled with the inert gas 23 are spatially separated from each other by a window. The window has a lock 31 e.g. B. from a titanium foil in a material thickness in the range of z. B. 0.01 mm and 0.3 mm, preferably at about 0.2 mm. The electron beam generator 28 has a cathode 32 e.g. B. in the form of a filament and one of the cathode 32 spaced anode 33 on. Electrons emerging from the cathode are separated by an between the cathode 32 and the anode 33 applied electrical voltage in the direction of the anode 33 accelerated to almost the speed of light. The electrical voltage for accelerating the electrons is dependent on a nature, e.g. B. chemical composition of the printing inks used and / or the desired depth of penetration into these printing inks and / or the material of the substrate used 21st in the area z. B. between 80 keV and 300 keV. The so accelerated high-energy electrons penetrate the z. B. consisting of the thin titanium foil closure 31 of the window and preferably meet substantially perpendicularly in the chamber contained in the inert gas 23 printed sheets passed by this window 21st . The high-energy electrons are so to speak on the substrate 21st ink applied. When these electrons hit the substrate 21st in a layer thickness of z. B. about 0.1 mm applied printing inks and upon penetration of the electrons into this color layer, a chemical chain reaction is triggered in these printing inks, in which short-chain acrylate molecules contained in the printing inks combine to form long-chain polymers, whereby a hardened color layer is formed in fractions of a second. The substrate 21st is not heated. Because the energy from the electron beam generator 28 on the substrate 21st shot electrons is large enough to generate the first radicals in the printing inks and to initiate the polymerization directly in the monomers (thinners) or oligomers (binders) of these printing inks, it is not necessary to add photoinitiators to the printing inks used, as described, for. B. would be required for a UV drying process.

Oligomers used in inks suitable for an intaglio printing process include e.g. B. epoxy acrylates, acrylated oils, urethane acrylates, polyester acrylates, silicone acrylates, acrylated amines, acrylic-saturated resins and acrylic acrylates.

Because of the high viscosity of most oligomers, diluents are required to reduce the overall viscosity of an electron beam curing ink and thereby aid in the handling and use of these inks, e.g. B. these inks for wiping on the plate cylinder 06 through the wiping cylinder 07 to make it suitable. Suitable diluents can include water or "reactive" monomers that are incorporated into the ink. Reactive monomers are typically acrylates or methacrylates and can be monofunctional or multifunctional. Examples of multifunctional monomers would be polyester acrylates or polyester methacrylates, polyol acrylates or polyomethacrylates and polyether acrylates or polyether methacrylates.

The following are some examples of the respective composition of layers of printing inks or lacquers, each of which can be dried using an electron beam:

example 1

Product name Manufacturer chemical name / further specification Proportion /% by weight Ebecryl ™ 83 (Eb 83) Cytec Surface Polyether acrylate oligomer 60 Specialties TPGDA Rahn or Sartomer Tripropylene glycol diacrylate 35 Darocur® 1173 Ciba Specialty Chemicals 2-hydroxy-2-methyl-1-phenyl-propan-1-one 5

Example 2

Product name Manufacturer chemical name / further specification Proportion /% by weight Ebecryl ™ 270 (Eb 270) Cytec Surface Specialties Urethane acrylate oligomer (aliphatic) 25th Ebecryl ™ 265 (Eb 265) Cytec Surface Specialties Urethane acrylate oligomer (aliphatic, trifunctional) 30th Genome 1122 Rahn Urethane acrylate (monofunctional) 40 Darocur® 1173 Ciba Specialty Chemicals 2-hydroxy-2-methyl-1-phenylpropan-1-one 5

Example 3

Product name Manufacturer chemical name / further specification Proportion /% by weight Ebecryl ™ 130 (Eb 130) Cytec Surface Specialties Tricyclodecane dimethanol diacrylate 25.0 Sartomer 238 (HDDA) Sartomer 1,6-hexanediol diacrylate 10.0 Miramer 600 (DPHA) Rahn Dipentaerythritol hexacrylate 5.0 Ebecryl ™ 220 (Eb 220) Cytec Surface Specialties Urethane acrylate oligomer (aromatic, hexafunctional) 40.0 Ebecryl ™ 83 (Eb 83) Cytec Surface Specialties Polyether acrylate oligomer (multifunctional) 11.8 Darocur® 1173 Ciba Specialty 2-hydroxy-2-methyl-1-phenyl 8.0 Chemicals propan-1-one Irgacure ™ 369 (IR 369) Ciba Specialty Chemicals 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone 0.2

Example 4

Product name Manufacturer chemical name / further specification Proportion /% by weight Cyracure ™ UVR-6110 Dow Chemical Company Epoxy resin (cycloaliphatic) 77.0 Castor Oil Gustav Heess Oleochemical Products GmbH castor oil 11.0 n-propanol OXEA Germany n-propanol 5.0 UVI-6992 Dow Chemical Company Mixture of triarylsulfonium hexafluorophosphate salts and propylene carbonate 7.0

Example 5

Product name Manufacturer chemical name / further specification Proportion /% by weight Cyracure ™ UVR-6110 Dow Chemical Company Epoxy resin (cycloalipathic) 81.0 UVI-6992 Dow Chemical Company Mixture of triarylsulfonium hexafluorophosphate salts and propylene carbonate 9.0 DVE-3 BASF Corporation Triethylene glycol divinyl ether 10.0

Example 6

Product name Manufacturer chemical name / further specification Proportion /% by weight Cyracure ™ UVR-6128 Dow Chemical Company Epoxy resin (cycloaliphatic) 69.0 UVI-6992 Dow Chemical Company Mixture of triarylsulfonium hexafluorophosphate salts and propylene carbonate 4.0 TONE ™ 0305 Dow Chemical Company Polyol (trifunctional) 27.0

Example 7

Product name Manufacturer chemical name / further specification Proportion /% by weight Cyracure ™ UVR-6110 Dow Chemical Company Epoxy resin (cycloalipathic) 60.0 TMPO® Perstorp Specialty Chemicals AB Trimethylolpropanoxetane 20.0 Boltorn H2004 Perstorp Specialty Chemicals AB dendritic polymer with high hydroxyl functionality 16.0 Irgacure® 250 Ciba Specialty Chemicals Idonium, (4-methylphenyl) [4- (2-methylpropyl) phenyl] -, hexafluorophosphate 3.5 Genocure ™ ITX Rahn Isopropylthioxanthone 0.5

For performing radiation drying on a substrate 21st applied printing inks or varnishes, each with an electron beam in a printing press for the industrial production of banknotes, security documents or security elements, some arrangement variants are now described below. In all of these arrangement variants, the drying unit shows 22 an electron beam generator 28 by means of which high-energy electrons on the substrate 21st be shot.

A first arrangement variant provides for the entire printing press to be arranged in a housing which is sealed with respect to the ambient air, an inert atmosphere with an oxygen content of at most 1% being provided in the interior of the housing. The chamber containing the inert gas 23 the drying unit 22 is realized by enclosing the printing press. The printed sheets to be printed 21st are fed to the printing press through an inlet lock formed on the housing and discharged from the printing machine through an outlet lock formed on the housing. The drying unit 22 is at any point in the transport direction in this first arrangement variant T which in particular as a printed sheet 21st trained substrates 21st after that of impression cylinder 04 and plate cylinder 06 formed pressure gap 17th arranged, e.g. B. also on or in the direction of transport T the press sheet 21st after that transport device 16 in the direction of transport T the press sheet 21st to the printing unit 03 arranged and z. B. is designed as a circulating conveyor belt or as a circulating chain system or as a chain gripper system.

A second arrangement variant provides for the drying unit 22 in the printing unit 03 to arrange the press. The chamber containing the inert gas 23 the drying unit 22 is like this in the printing unit 03 arranged that at least one arc section of the printing cylinder 04 inside this chamber 23 is arranged.

3rd shows a section of the in the 1 illustrated printing press, wherein a sheet section of the printing cylinder 04 and an arc portion of the with this impression cylinder 04 interacting plate cylinder 06 inside the chamber containing the inert gas 23 are arranged. It is at the chamber containing the inert gas 23 a preferably flexible seal 34 arranged which this chamber 23 on the respective end faces of the pressure cylinder 04 and plate cylinder 06 and on the outer surface of the plate cylinder 06 as well as, if applicable, that of the pressure cylinder 04 and plate cylinder 06 formed pressure gap 17th and at an exit from the chamber 23 on the outer surface of the rotating printing cylinder 04 overlying dried substrate 21st seals against the ambient air. It is remarkable that the pressure cylinder 04 and the plate cylinder 06 in the pressure gap they formed 17th in a printing process carried out by the printing press in question, under high pressure, and the cylinders, which are positioned against each other 04 ; 06 in the pressure gap they formed 17th already one axially to these cylinders 04 ; 06 running seal for the chamber containing the inert gas 23 form. By means of the drying unit 22 dried substrates 21st , especially printed sheets 21st are from the impression cylinder 04 to one of the impression cylinders 04 in the direction of transport T the press sheet 21st subsequent transport device 16 to hand over.

4th also shows a section of the in the 1 illustrated printing press, wherein only one sheet section of the printing cylinder 04 inside the chamber containing the inert gas 23 is arranged. At the chamber containing the inert gas 23 is a preferably flexible seal 34 arranged which this chamber 23 on the front of the impression cylinder 04 and at an exit from the chamber 23 on the dry substrate lying on its lateral surface 21st seals against the ambient air. At the entrance to the chamber 23 is a cross to the direction of transport T of the substrate 21st Narrow slot extending over its entire width, through which slot a on the outer surface of the printing cylinder 04 overlying substrate 21st into the chamber 23 the drying unit 22 is introduced or is at least insertable, with a doctor nozzle along this slot 24th is arranged in particular in the form of a nozzle bar to prevent the inert gas from the chamber at this inlet 23 escapes and / or oxygen from the ambient air into this chamber 23 entry. In this embodiment too, the drying unit 22 dried substrates 21st , especially printed sheets 21st from the impression cylinder 04 to one of the impression cylinders 04 in the direction of transport T the press sheet 21st subsequent transport device 16 to hand over.

5 also shows a section of the in the 1 shown printing press, in contrast to that in the 1 illustrated embodiment in the pressure nip 17th between the impression cylinder 04 and the plate cylinder 06 printed printed sheets 21st over two in the direction of transport T the press sheet 21st successively arranged intermediate cylinders 36 ; 37 to the transport device 16 be handed over. A third arrangement variant provides that the drying unit 22 on one of the intermediate cylinders 36 ; 37 is arranged. At the chamber containing the inert gas 23 is again a preferably flexible seal 34 arranged which this chamber 23 on the end faces of the intermediate cylinder concerned 36 ; 37 and at an exit from the chamber 23 on the outer surface of the intermediate cylinder in question 36 ; 37 overlying dry substrate 21st seals against the ambient air. At the Entrance to the chamber 23 is a cross to the direction of transport T of the substrate 21st formed across its entire width narrow slot, through which slot a on the outer surface of the intermediate cylinder in question 36 ; 37 overlying substrate 21st into the chamber 23 the drying unit 22 is introduced or is at least insertable, with a doctor nozzle along this slot 24th is arranged in particular in the form of a nozzle bar to prevent the inert gas from the chamber at this inlet 23 escapes and / or oxygen from the ambient air into this chamber 23 entry.

Like in the 6 Illustrated as an example, the fourth arrangement variant provides that the drying unit 22 on or at least in connection with the z. B. formed as a conveyor belt transport device 16 is arranged. At the chamber containing the inert gas 23 is again a preferably flexible seal 34 arranged which this chamber 23 at the exit from the chamber 23 on from the transport facility 16 transported dry substrate 21st seals against the ambient air. At the entrance to the chamber 23 is a cross to the direction of transport T of the substrate 21st Narrow slot formed over its entire width, through which slot one of the transport device 16 transported substrate 21st into the chamber 23 the drying unit 22 is introduced or is at least insertable, with a doctor nozzle along this slot 24th is arranged in particular in the form of a nozzle bar to prevent the inert gas from the chamber at this inlet 23 escapes and / or oxygen from the ambient air into this chamber 23 entry.

As shown in the second to fourth arrangement variants, the one chamber containing the inert gas can 23 having drying unit 22 e.g. B. in the printing unit 03 the printing press or on one in the transport direction T of the substrates 21st after the printing unit 03 arranged intermediate cylinder 36 ; 37 or on which the substrates 21st to a display 18th transporting transport device 16 be arranged.

The 7 and 8th schematically show examples of different designs of the drying unit 22 for electron beam hardening. So shows 7 one to a suction cylinder 38 employed drying unit 22 for electron beam hardening, the suction cylinder 38 a special configuration z. B. the impression cylinder 04 or an intermediate cylinder 36 ; 37 can be and at least one inside the chamber 23 the drying unit 22 has located arc section. One in the direction of transport T of the substrates 21st the suction cylinder 38 immediately upstream first transport device z. B. in the form of a conveyor belt, especially one preferably a suction box 41 having suction belt 39 , or a cylinder or a roller carries printed substrates 21st the suction cylinder 38 sequentially too, the suction cylinder 38 several, for. B. three in particular as a printed sheet 21st trained substrates 21st can record. The suction cylinder 38 supplied substrates 21st are held on the lateral surface by suction air. With continued rotation of the suction cylinder 38 become the printed substrates 21st through a cross to the direction of transport T of the substrates 21st Narrow slot extending over its entire width into the chamber containing the inert gas 23 the drying unit 22 guided. In the drying unit 22 is the electron beam generator 28 which is the printed substrates 21st by bombardment with high-energy electrons in the manner described above. The on the outer surface of the rotating suction cylinder 38 overlying dry substrates 21st leave the drying unit 22 at the exit of the chamber 23 , the exit of the chamber 23 as a transverse to the direction of transport T of the substrates 21st Narrow slit extending over its entire width and preferably by a particularly flexible seal 34 is sealed. In the direction of rotation of the suction cylinder 38 and thus in the direction of transport T of the substrates 21st is just behind the exit from the chamber 23 a second transport device z. B. again in the form of a conveyor belt, in particular a preferably a suction box 43 having suction belt 42 , or a cylinder or a roller arranged, the dried substrates 21st e.g. B. to a display 18th transported.

As from the 7 can be seen, two separate pneumatic systems are provided in this embodiment. The first pneumatic system uses a pump 44 and usually over corresponding lines z. B. on the suction cylinder 38 and / or on the suction box 41 of the suction belt 39 the first transport device and / or on the suction box 43 of the suction belt 42 the second transport device the suction air required in each case for holding the substrates to be transported 21st to disposal. The second pneumatic system has an inert gas source z. B. in the form of a tank 46 to provide the drying unit 22 required inert gas, preferably those on the chamber 23 the drying unit 22 arranged, inert gas into the chamber 23 inlet filling nozzle 26 with this tank 46 connected is. Furthermore, the second pneumatic system has a z. B. with the suction cylinder 38 and on the outlet side with the tank 46 connected pump 47 on to a substrate 21st which is on the inside of the chamber 23 the drying unit 22 located arc section of the suction cylinder 38 is arranged on the outer surface of this suction cylinder 38 hold by suction. In this respect, the second pneumatic system also generates suction air, wherein this suction air used in the second pneumatic system has an inert atmosphere with a significantly reduced oxygen compared to the ambient air usually used by the first pneumatic system, with an oxygen content of preferably at most 1%. It is advantageously provided that the first pneumatic system and the second pneumatic system are formed separately from one another, the first pneumatic system on the suction cylinder 38 the suction air required to hold the substrates to be transported 21st provides if there is a on the outer surface of the suction cylinder 38 held substrate 21st outside the chamber 23 the drying unit 22 and that the second pneumatic system provides the suction air required to hold the substrates to be transported 21st at least available if that is on the outer surface of the suction cylinder 38 held substrate 21st inside the chamber 23 the drying unit 22 located.

In a further embodiment it is provided that, for. B. only a single pneumatic system is provided, the necessary suction air for holding the on the outer surface of the suction cylinder 38 substrates to be transported 21st especially during their entire stay on the suction cylinder in question 38 the same gaseous medium as in the chamber 23 the drying unit 22 provided. This results in z. B. a rotary printing press with at least one printing unit 03 for printing on substrates 21st , the relevant printing unit 03 at least two interacting cylinders 04 ; 06 has, at least one of these cylinders 04 ; 06 as a the substrates 21st on its lateral surface transporting suction cylinder is formed, a pneumatic system for providing the necessary suction air for holding the on the lateral surface of the cylinder in question 04 ; 06 substrates to be transported 21st is provided. This is in or after the printing unit in question 03 in the transport path of the substrates 21st a drying unit 22 provided, by the printing unit in question 03 printed substrates 21st through a chamber 23 this drying unit 22 are guided or at least feasible, being in the chamber 23 the drying unit 22 a gaseous medium which is oxygen-reduced by an inert gas is provided. In an advantageous embodiment, the suction air provided in the pneumatic system is used to hold the substrates to be transported on the lateral surface of the suction cylinder in question 21st the same gaseous medium as in the chamber 23 the drying unit 22 . Are preferably one of the in the printing unit in question 03 interacting cylinders 04 as a pressure cylinder 04 and the other with the impression cylinder 04 interacting cylinders 06 as a print image on the substrates in question 21st brushing plate cylinder 06 educated. The printing unit in question is in the most preferred embodiment 03 as a printing unit printing in a gravure printing process, in particular in an intaglio printing process 03 educated.

8th shows an embodiment of the drying unit 22 for electron beam curing, for the transport of substrates 21st through the chamber 23 the drying unit 22 in one which is the electron beam generator 28 having vacuum chamber 29 partially, e.g. B. semicircular enclosing housing 49 along the transport path of the substrates 21st several suction rolls 48 are provided, these suction rolls 48 through their respective rotation into the chamber 23 the drying unit 22 imported substrates 21st from an entrance to the chamber 23 to their exit. The electron beam generator 28 is z. B. in or near the center of the drying unit 22 arranged stationary and has a radially outwardly directed electron beam, with substrates to be dried 21st the electron beam generator with its printed side 28 facing at least partially along their transport route, e.g. B. in a semicircle in an arc around the electron beam generator 28 having vacuum chamber 29 are led around. The along the transport route of the substrates 21st arranged suction rolls 48 are on the non-drying side of the chamber 23 the drying unit 22 substrates to be promoted 21st arranged. The entrance to the chamber 23 and their output are preferably each as a transversely to the direction of transport T of the substrates 21st formed across its entire width narrow slot. One in the direction of transport T of the substrates 21st immediately before the entrance to the chamber 23 arranged first transport device is such. B. in the form of a conveyor belt, especially one preferably a suction box 41 having suction belt 39 , or a cylinder or a roller and carries printed substrates 21st the chamber 23 the drying unit 22 sequentially too. In the direction of transport T of the substrates 21st is just behind the exit from the chamber 23 a second transport device z. B. again in the form of a conveyor belt, in particular a preferably a suction box 43 having suction belt 42 , or a cylinder or a roller arranged, the dried substrates 21st e.g. B. to a display 18th transported.

In the variant according to the 8th are z. B. again two separate pneumatic systems are provided. The first pneumatic system uses a pump 44 and via corresponding lines z. B. on the suction box 41 of the suction belt 39 the first transport device and / or on the suction box 43 of the suction belt 42 the second transport device the suction air required in each case for holding the substrates to be transported 21st to disposal. The second pneumatic system has an inert gas source z. B. in the form of a tank 46 to provide the drying unit 22 required inert gas, the one on the chamber 23 the drying unit 22 arranged, inert gas into the chamber 23 inlet filling nozzle 26 with this tank 46 connected is. Furthermore, the second pneumatic system z. B. one on the input side with the suction rolls 48 and on the outlet side with the tank 46 connected pump 47 on being a substrate 21st which is on the inside of the chamber 23 the drying unit 22 transport route through the suction rolls 48 is conveyed by a pump 47 caused suction is kept on the intended transport route.

Since the provision of an inert gas, e.g. B. of nitrogen, in a drying unit integrated in an industrial production process 22 for electron beam curing associated with considerable costs is that for the substrates 21st intended entrance to the chamber 23 the drying unit 22 and / or the exit from this chamber 23 each z. B. slit-shaped and / or z. B. by a doctor nozzle 24th in particular in the form of a nozzle bar or by a preferably flexible seal 34 sealed.

Another measure to minimize the escape of the oxygen-reduced gaseous medium, in particular of inert gas from the chamber 23 and / or an undesirable entry of oxygen from the ambient air into this chamber 23 is channels 51 or grooves 51 that at one the chamber 23 the drying unit 22 at least partially, e.g. B. in an arc section cylinder, z. B. on a pressure cylinder 04 or on a plate cylinder 06 or on an intermediate cylinder 36 ; 37 or on a suction cylinder 38 are designed to cover each with a cover. If in such a way, it is particularly transverse to the direction of transport T of the substrates 21st channel across its width 51 at least one gripper for holding a substrate 21st is arranged on the respective lateral surface of the cylinder in question, which has this channel 51 covering cover at the location of the gripper in question. Regarding the tightness of the chamber 23 the drying unit 22 however, it is of advantage to the cylinders in question 04 ; 06 ; 36 ; 37 ; 38 in each case without a gripper, ie without a mechanical gripper or in the case of interacting cylinders 04 ; 06 like the impression cylinder 04 and the plate cylinder 06 at least one of these cylinders 04 ; 06 training without a gripper. On gripper-free cylinders 04 ; 06 ; 36 ; 37 ; 38 become substrates to be arranged on their respective outer surface 21st preferably held only by suction air. It is also advantageous to have a transport device designed as a transport belt 16 for the transport of substrates 21st training without a gripper.

Thus there is z. B. a rotary printing press with at least one printing unit 03 for printing on substrates 21st , being in the transport path of the substrates 21st in or after the at least one printing unit 03 a drying unit 22 is provided, with at least one printing unit 03 printed substrates 21st through a chamber 23 this drying unit 22 are guided or at least feasible, being in the chamber 23 the drying unit 22 an atmosphere reduced by an inert gas is provided, the chamber 23 the drying unit 22 at least one sheet section from one of the substrates to be dried 21st transporting cylinder 04 ; 06 ; 36 ; 37 ; 38 encloses, this cylinder 04 ; 06 ; 36 ; 37 ; 38 in one that is transverse to the direction of transport T of the substrates 21st extending channel 51 at least one gripper for holding one of the substrates 21st on the outer surface of the cylinder in question 04 ; 06 ; 36 ; 37 ; 38 has, the channel in question 51 is covered with a cover, the cover having a recess at the location of the gripper in question, the cylinder in question 04 ; 06 ; 36 ; 37 ; 38 on its lateral surface in addition to the at least one gripper, at least one further holding element for holding the substrate in question 21st on the outer surface of the cylinder in question 04 ; 06 ; 36 ; 37 ; 38 having.

Alternatively, z. B. a rotary printing press with at least one printing unit 03 for printing on substrates 21st , being in the transport path of the substrates 21st in or after the at least one printing unit 03 a drying unit 22 is provided, with at least one printing unit 03 printed substrates 21st through a chamber 23 this drying unit 22 are guided or at least feasible, being in the chamber 23 the drying unit 22 an atmosphere reduced by an inert gas is provided, the chamber 23 the drying unit 22 at least one sheet section from one of the substrates to be dried 21st transporting cylinder 04 ; 06 ; 36 ; 37 ; 38 encloses, this cylinder 04 ; 06 ; 36 ; 37 ; 38 is designed without a gripper.

A special design variant is e.g. B. in a rotary printing press with at least one printing unit 03 for printing on substrates 21st , being in the transport path of the substrates 21st in or after the at least one printing unit 03 a drying unit 22 is provided, with at least one printing unit 03 printed substrates 21st through a chamber 23 this drying unit 22 are guided or at least feasible, being in the chamber 23 the drying unit 22 one by one Inert gas oxygen-reduced atmosphere is provided, being in the chamber 23 the drying unit 22 along the transport path of the substrates 21st several suction rolls 48 are arranged, the suction rolls 48 through their respective rotation the substrates 21st through this chamber 23 promote.

A concrete variant is also z. B. by a sheet-fed printing machine with at least one printing unit 03 for printing printed sheets 21st given, the printed sheet in the transport path 21st in or after the at least one printing unit 03 a drying unit 22 is provided, with at least one printing unit 03 printed printed sheets 21st through a chamber 23 this drying unit 22 are guided or at least feasible, being in the chamber 23 the drying unit 22 an atmosphere reduced by an inert gas is provided, the drying unit 22 an electron beam generator 28 for drying the printed sheets 21st by means of one in the chamber 23 has directed electron beam, the atmosphere in the chamber 23 the drying unit 22 has an oxygen content of at most 1%.

Furthermore, there is z. B. a gravure printing machine with at least one printing unit 03 for printing printed sheets 21st , being in the printing unit in question 03 a pressure cylinder 04 and one with this pressure cylinder 04 interacting plate cylinder 06 are arranged, one against the plate cylinder 06 employed or at least adjustable wiper cylinder 07 is provided, the printed sheet in the transport path 21st in or after the at least one printing unit 03 a drying unit 22 is provided, with at least one printing unit 03 printed printed sheets 21st through a chamber 23 this drying unit 22 are guided or at least feasible, the drying unit 22 an electron beam generator 28 for drying the printed sheets 21st by means of one in the chamber 23 directed electron beam.

Further refinements and / or developments of the aforementioned printing machines result from each sensible and thus contradictory combination of the features described above by way of example.

9 now shows a variant that is particularly suitable for retrofitting in a printing press. This embodiment variant relates to a drying unit 22 for drying printed sheets, preferably as printed sheets 21st trained substrates 21st with a chamber containing a gaseous medium 23 , which is in the chamber 23 contained gaseous medium is oxygen-reduced by an inert gas. This drying unit 22 In the preferred embodiment, forms an independent structural unit, which can also be retrofitted, in particular into a printing press, in the transport path of the printed substrates 21st can be introduced. The substrates to be dried 21st are through the chamber 23 this drying unit 22 passed through or at least feasible. The chamber 23 points in the direction of transport T of the substrates 21st a preferably slit-shaped transversely to the direction of transport T of the substrates 21st extending entrance for those in this chamber 23 leading substrates 21st on, with the entrance for into the chamber 23 substrates to be led 21st through a nip 17th between two cylinders, which are positioned longitudinally against each other, particularly under high pressure 04 ; 06 is trained. The respective direction of rotation of these two cylinders 04 ; 06 is in the 9 each indicated by an arrow indicating the direction of rotation. Advantageously, the two cylinders are positioned against each other 04 ; 06 at this entrance to the chamber 23 a seal against the escape of the oxygen-reduced gaseous medium, in particular of inert gas from this chamber 23 and / or against the entry of oxygen from the ambient air into this chamber 23 out. In the drying unit 22 is for drying the printed substrates 21st preferably an electron beam generator 28 with one in the chamber 23 on the substrates 21st directed electron beam provided. Especially in the latter embodiment i. V. m. an electron beam generator 28 has the atmosphere, ie the gaseous medium in the chamber 23 - As already described above - an oxygen content of at most 1%. The chamber 23 this drying unit 22 points in the direction of transport T of the substrates 21st of course also a slit-shaped one, transverse to the direction of transport T of the substrates 21st extending exit for through this chamber 23 guided substrates 21st on, at this outlet as a seal against the escape of the oxygen-reduced gaseous medium, in particular of inert gas, from this chamber 23 and / or against the entry of oxygen from the ambient air into this chamber 23 a preferably flexible seal 34 and / or a doctor nozzle 24th is or are arranged.

In an advantageous development, the two cylinders, which are positioned against one another, form 04 ; 06 at the entrance to the chamber 23 a printing unit 03 out with one of the cylinders 04 as a pressure cylinder 04 and the other cylinder 06 than one with the impression cylinder 04 interacting a print image on the substrates in question 21st brushing plate cylinder 06 are trained. This is at the entrance to the chamber 23 the drying unit 22 trained printing group 03 e.g. B. as a printing unit printing in a gravure printing process, in particular in an intaglio printing process 03 educated.

A transport device is advantageous 16 provided, the transport device 16 the substrates 21st through the chamber 23 is arranged leading through, the transport device 16 is designed as a preferably rotating conveyor belt or as a preferably rotating chain system, in particular as a chain gripper system. It can also be provided that at least one of the two at the entrance to the chamber 23 opposed cylinders 04 ; 06 is designed as a suction cylinder. Alternatively or additionally, e.g. B. at least one of the two at the entrance to the chamber 23 opposed cylinders 04 ; 06 in one that is transverse to the direction of transport T of the substrates 21st extending channel 51 at least one gripper for holding one of the substrates 21st on the outer surface of the cylinder in question 04 ; 06 on. Here is the channel in question 51 preferably covered with a cover, the cover having a recess at the location of the gripper in question.

Reference symbol list

01

Sheet feeder

02

Bow system

03

Printing unit

04

Impression cylinder; cylinder

05

-

06

Plate cylinder; cylinder

07

Wiper cylinder

08

Collecting cylinder; Orlof cylinder

09

Inking unit

10th

-

11

Stencil cylinder

12

Inking roller

13

Color ductor

14

Color reservoir

15

-

16

Transport device

17th

Pressure gap; Nip

18th

Display; Sheet delivery

19th

Inspection system

20th

-

21st

Substrate; Printed sheet

22

Drying unit

23

chamber filled with an inert gas

24th

Doctor nozzle

25th

-

26

Filling nozzle

27th

Sensor for oxygen measurement

28

Electron beam generator

29

Vacuum chamber

30th

-

31

Clasp

32

cathode

33

anode

34

poetry

35

-

36

Intermediate cylinder

37

Intermediate cylinder

38

Suction cylinder

39

Suction belt

40

-

41

Suction box

42

Suction belt

43

Suction box

44

pump

45

-

46

tank

47

pump

48

Suction roll

49

casing

50

-

51

Channel; Groove

T

Direction of transport

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2005/097927 A1 [0002]
• DE 102006032679 A1 [0003]
• DE 102016200544 A1 [0004]

Claims (10)

Sheet printing machine with at least one printing unit (03) for printing printed sheets (21), a drying unit (22) being provided in or after the at least one printing unit (03) in the transport path, of which at least one printing unit (03 ) printed printed sheets (21) are guided or at least can be guided through a chamber (23) of this drying unit (22), an atmosphere reduced in oxygen by an inert gas being provided in the chamber (23) of the drying unit, characterized in that the drying unit (22) has an electron beam generator (28) for drying the printed printed sheets (21) by means of an electron beam directed into the chamber (23), the atmosphere in the chamber (23) of the drying unit (22) having an oxygen content of at most 1% having. Sheet printing machine after Claim 1 characterized in that the chamber (23) of the drying unit (22) is traversed by a conveyor belt transporting the printed sheets (21) to be dried, or this chamber (23) encloses at least one sheet section of a cylinder transporting the printed sheets (21) to be dried, this cylinder being designed as a pressure cylinder (04) or as a plate cylinder (06) or as an intermediate cylinder (36; 37) or as a suction cylinder (38). Sheet printing machine after Claim 2 , characterized in that the conveyor belt is part of a transport device (16) which transports the printed printed sheets (21) to a sheet delivery (18). Sheet printing machine after Claim 1 , characterized in that a plurality of suction rollers (48) are arranged in the chamber (23) of the drying unit (22) along the transport path of the printing sheets (21) in such a way that the printing sheets (21) are rotated through this chamber (23) by their respective rotation promote. Sheet printing machine after Claim 1 or 2nd or 3rd or 4th , characterized in that the chamber (23) of the drying unit (22) has an inlet and an outlet for the printed sheets (21) to be passed through it, the inlet and / or the outlet each being a transverse to the transport direction (T) of the Printing sheet (21) over the entire width of the slot is or are formed. Sheet printing machine after Claim 5 , characterized in that the chamber (23) of the drying unit (22) at its inlet and / or at its outlet each by a flexible seal (34) or by a doctor nozzle (24), in particular in the form of a nozzle bar against the escape of the Inert gas oxygen-reduced atmosphere from this chamber (23) and / or against the entry of oxygen from the ambient air into this chamber (23) is sealed. Sheet printing machine after Claim 1 or 2nd or 3rd or 4th or 5 or 6 , characterized in that in each case in the chamber (23) of the drying unit (22) there is a remotely operable filling nozzle (26) connected to an inert gas source and a sensor (27) for measuring the oxygen content present in this chamber (23), the oxygen content in the inert atmosphere prevailing in this chamber (23) by a control unit as a function of the measurement result of the sensor (27) for measuring the oxygen content and / or as a function of the material of the printed sheets (21) to be dried and / or as a function of the chemical composition at least one printing ink applied to the printing sheets (21) or at least one lacquer applied to the printing sheets (21) is set. Sheet printing machine after Claim 2 or 3rd or 4th or 5 or 6 or 7 , characterized in that the pressure cylinder (04) or the plate cylinder (06) or the intermediate cylinder (36; 37) or the suction cylinder (38) is designed without a gripper. Sheet printing machine after Claim 2 or 3rd or 4th or 5 or 6 or 7 or 8th , characterized in that the printing cylinder (04) or the plate cylinder (06) or the intermediate cylinder (36; 37) or the suction cylinder (38) has at least one each on its lateral surface transverse to the transport direction (T) of the printing sheet (21) over their Has wide channel (51), the channel (51) in question being covered by a cover. Sheet printing machine after Claim 1 or 2nd or 3rd or 4th or 5 or 6 or 7 or 8th or 9 , characterized in that the at least one printing unit (03) is designed as a printing unit (03) printing the printing sheets (21) in each case in an intaglio printing process.

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