Patent Description:
Printing machines following different modes of action are known in the art and are used for different kinds of printing products. , flexographic printing machines utilize so-called anilox rolls for taking up ink. Anilox rolls have engraved dimples on their surface in which the ink is collected and then transferred to a printing substrate. Flexographic printing is especially suited for uneven printing substrates due to the flexibility of the dimples. Gravure printing machines use gravure cylinders comprising depressions for taking up and transferring the ink to the printing substrate. Gravure printing machines are especially suitable for high-throughput applications.

Depending on the current print job at hand, manufacturers need to be able to easily choose the suitable printing mode. In known solutions, a combination of flexographic printing and gravure printing is typically realized by providing individual printing modules or individual printing machines for each type of printing. Therefore, space requirements and costs are high. Some printing machines comprise combined printing units which can be manually switched between a flexographic and a gravure printing mode. However, this change requires a high number of manual steps done by an operator of the printing machine which needs highly trained personnel, requires complex handling operations and makes extended set-up times of the printing machine necessary.

<CIT> discloses a printing module having a flexographic and an intaglio printing mode based on a combination of an exchangeable printing cylinder <NUM> and a second printing cylinder with exchangeable sleeves. For switching between the different printing modes, the exchangeable printing cylinder is lowered onto a carriage system which is then used to withdraw the exchangeable printing cylinder from the printing module and inserting a different one. Then, the exchangeable sleeve is removed from the second printing cylinder and a new sleeve is mounted thereon.

<CIT> discloses a flexographic printing machine with a plurality of printing stations. At least one of the printing stations has movable printing cylinders comprising an anilox roller and a printing plate cylinder, wherein the anilox roller can be replaced with an engraved roller and the printing plate cylinder can be replaced with a rubber roller.

<CIT> shows a method of assembling or transforming a print unit belonging to a printing machine comprising a frame. By means of a print carriage, a doctor blade system can be inserted into and attached to the frame.

From <CIT>, a modular narrow-band label printer is known which is built from a multitude of interconnected individual modules, wherein the label printer comprises at least two carrying modules and three processing modules. The processing modules can be printing modules, e.g. for flexographic printing, digital printing or digital printing, or modules for converting modules like a stamping module or a cutting module.

It is an object of the invention to provide a means for switching between flexographic and gravure printing in an easy and fast manner.

The object of the invention is solved by a printing machine according to claim <NUM>.

The object of the invention is solved by a printing machine with a printing module having a flexographic printing mode and a gravure printing mode, wherein the printing module comprises at least two printing cylinders defining the printing mode of the printing module, and a printing tool handling unit being configured for withdrawing and inserting the at least two printing cylinders from and into the printing module, respectively. The printing tool handling unit comprises a coupling interface and the at least two printing cylinders each comprise a complementary coupling interface such that the printing tool handling unit can at least temporarily be coupled to one or more of the at least two printing cylinders via the respective coupling interfaces. The coupling interface provided on the printing tool handling unit and each of the complementary coupling interfaces provided on the at least two printing cylinders are standardized such that the same coupling interface provided on the printing tool handling unit can be used to be coupled to the complementary coupling interface of each of the at least two printing cylinders.

The printing assembly according to the invention allows for a fast procedure for switching between a flexographic printing mode and a gravure printing mode of a single printing module. Accordingly, it is not necessary to provide individual printing assemblies with each of these being configured for a single printing mode.

The printing module can be the only printing module of the printing machine or be used in combination with further printing modules. , the printing module can be combined with a conventional flexographic printing module and/or a gravure printing module to allow for flexible printing processes using combined printing procedures. Also, the printing module can be combined with sheet-processing modules, e.g. with a creasing, cutting and/or folding module to allow a combined process including printing on a substrate and processing the substrate in a desired form.

In another preferred embodiment of the invention the printing machine may further comprises a digital printing unit. The digital printing unit may be used in addition to the other modules, depending on the print job and the embodiment.

The printing tool handling unit of the printing assembly ensures a fast and easy switching procedure between the flexographic and gravure printing mode by means of the coupling interface and the complementary coupling interfaces. In the present context, "withdrawing" a printing tool from the printing module means unloading the printing tool from the printing module and "inserting" a printing tool into the printing module is the same as loading the printing tool into the printing module.

The printing tool handling unit can be coupled to a single one or more than one of the printing tools at the same time when withdrawing and/or inserting the printing tools.

The coupling interfaces provided on the printing tool handling unit and on each of the printing tools are standardized. Therefore, the same coupling interface can be used for the different printing tools necessary for the different printing modes. This reduces the costs and complexity of the printing tool handling unit and decreases set-up times.

In the flexographic printing mode, the at least two printing cylinders can comprise a plate cylinder and an anilox roll.

In the gravure printing mode, the at least two printing cylinders comprise a gravure cylinder and a pressure roller.

In one variant, the printing module further comprises an ink tray which is displaceable between a rest position and an operation position, wherein the ink tray is in the rest position, when the printing module is in the flexographic printing mode and in the operation position when the printing module is in the gravure printing mode. In the rest position, the ink tray has no contact with the printing cylinders and in the operation position the ink tray is in contact with at least one of the printing cylinders for supplying ink to said printing cylinder.

Especially, the ink tray is in contact with the gravure cylinder for supplying ink to the gravure cylinder in the operation position.

By providing a displaceable ink tray, there is no need to insert and withdraw the ink tray when switching between the flexographic and gravure printing mode which can reduce the complexity of the printing tool handling unit and decreases the set-up time of the printing machine.

However, the printing tool handling unit can still be configured for withdrawing and inserting the ink tray from and into the printing module, respectively, e.g. to allow for an easy access to the ink tray for maintenance and for exchanging the ink tray at the end of its lifetime. For this purpose, the ink tray preferably comprises a coupling interface which is analogue to the complementary coupling interfaces of the printing cylinders, i.e. the printing tool handling unit can preferably be at least temporarily be coupled to the blade beam via the same coupling interface as is the case for the printing cylinders.

The ink tray can be displaceable by means of a linear guide and driven by a drive, e.g. a spindle drive.

The printing tool handling unit can be further configured for withdrawing and inserting a blade beam from and into the printing module, respectively.

This allows for easily providing the blade beam necessary for the respective printing mode. In the gravure printing mode, the blade beam is especially a doctor blade or squeegee. In the flexographic printing mode, the blade beam is especially a doctor chamber blade. Additionally, the blade beam necessary for the printing mode to be changed into can be prepared upfront of the set-up procedure for changing the printing mode, thereby reducing the actual down-times of the printing machine.

The blade beam preferably comprises a coupling interface which is analogue to the complementary coupling interfaces of the printing cylinders, i.e. the printing tool handling unit can preferably be at least temporarily be coupled to the blade beam via the same coupling interface as is the case for the printing cylinders.

To allow for a standardized supply with inks, the printing module can comprise an ink supply module which is in fluid connection with the printing module by means of an ink connector. In the flexographic printing mode, the ink connector is especially coupled by means of the ink connector to the chamber doctor blade. In the gravure printing mode, the ink connector is especially coupled by means of the ink connector to the ink tray. With other words, the ink connector, the doctor chamber blade and the ink tray especially use a standardized coupling to allow for an easy and fast exchange of the ink supply setup when switching between the flexographic and gravure printing mode.

For minimizing the space requirements and to allow for printing on a front side and a back side of a printing substrate, the printing cylinders are preferably arranged symmetrically along a vertical central axis of the printing module. With other words, the printing cylinders are preferably arranged along the vertical central axis on top of each other.

The printing cylinders are preferably be displaceable along the vertical central axis, e.g. driven by a drive like a spindle drive and guided along a linear guide. This allows optimizing the position of the printing cylinders before and/or after the printing tool handling unit has withdrawn and inserted the respective printing tools. , before withdrawing the printing cylinders at least one of the printing cylinders is displaced to have no contact with other printing cylinders to allow for higher tolerances when being handled by the printing tool handling unit and minimizing the risk of damages of the printing cylinder during the set-up of the printing module.

The printing module can further comprise a drying unit which is arranged symmetrically along the vertical central axis of the printing module and geodetically above the printing cylinders, wherein the drying unit is configured to dry both the front and back side of a printed substrate. Especially, the drying unit is arranged geodetically above the printing cylinders. This allows for a very compact design of the printing module while providing drying of the printed substrate, especially drying of both the front and back side of the printed substrate.

According to a variant, the printing tool handling unit comprises an end effector, wherein the coupling interface is mounted on or provided at the end effector. The end effector and the coupling interface mounted thereon or provided thereat may thus be provided as a module which can be used in connecting with varying handling devices. Consequently, the printing tool handling unit can be produced and operated at comparatively low costs.

Preferably, the end effector is mounted at or provided on an end of an arm. A printing tool handling unit having such an arm is able to cover a relatively large range of motion. Consequently, the printing tool handling unit can interact with printing tools being arranged at different positions and especially different heights within the printing module.

In an especially preferred variant, the arm is a robot arm and thus the printing tool handling unit comprises an industrial robot. As a consequence thereof, the printing tool handling unit can rely on standard equipment which is to be equipped with the coupling interface. Further, the procedure for switching between the flexographic printing mode and the gravure printing mode can be performed fully automatically for minimizing the set-up time of the printing machine.

According to a further variant, at least one of the printing cylinders is a roller assembly comprising a shaft and a sleeve mounted onto the shaft, wherein the complementary coupling interface is located at an end of the shaft. Thus, the printing cylinder can be maneuvered in a stable and reliable manner. Moreover, the risk of damaging a sleeve and/or an adapter of the printing cylinder is reduced. This is especially true in comparison to known printing tools, wherein the sleeve and/or the adapter are gripped when performing an exchange procedure.

Further, at least one of the printing cylinders can be formed as a beam, wherein the complementary coupling interface is located at an end of the beam. Thus, also beam-shaped printing tools can be exchanged in a simple and reliable manner.

Further advantages and features will become apparent from the following description of the invention and from the appended figures which show nonlimiting exemplary embodiments of the invention and in which:.

<FIG> schematically shows a printing assembly <NUM> according to the invention comprising a printing machine <NUM>.

The printing assembly <NUM> comprises a loading station <NUM> from which an operator <NUM> can load a printing substrate <NUM> into an unwinding station <NUM>.

The printing substrate <NUM> can be paper, foil or any other suitable printing substrate <NUM> as known in the art.

From the unwinding station <NUM>, the printing substrate <NUM> is guided in form of a material web <NUM> towards a flexographic printing station <NUM> which is a satellite flexographic printing station.

The material web <NUM> is then dried in a drying tunnel <NUM> and transported through a web inspection station <NUM> to a printing module <NUM>.

The printing module <NUM> has a flexographic printing mode and a gravure printing mode. Accordingly, different types of printing operations can be achieved by the printing module <NUM>.

From the printing module <NUM>, the material web <NUM> is then transported to a rewinding station <NUM> from which the finished printed substrate <NUM> can be collected by the operator <NUM>.

In the shown embodiment, the printing module <NUM> is combined with a flexographic printing station <NUM>. However, as will be apparent for one skilled in the art, the printing assembly <NUM> could also merely use one or more printing modules <NUM>, i.e. without using other types of printing stations, and/or other kinds of additional printing stations and additional processing stations.

In <FIG>, the printing module <NUM> is shown in more detail.

The printing module <NUM> comprises several printing cylinders which are arranged along a vertical central axis of the printing module <NUM> indicated by the dashed line in <FIG>.

From bottom to top along the vertical central axis are arranged a first printing cylinder <NUM>, a second printing cylinder <NUM>, an impression cylinder <NUM>, a nip roll <NUM> and a tension sensing roller <NUM> for measuring the tension of the material web <NUM>.

The material web <NUM> is guided to, within and from the printing module <NUM> by a multitude of guide rollers <NUM> and is heated or cooled to a target temperature by temperature control rollers <NUM>.

The printing module <NUM> further comprises an ink tray <NUM> which is displaceable along the vertical central axis by means of a (not shown) drive and guided along (not shown) linear guides. A fountain roller <NUM> is arranged in the ink tray <NUM>.

Arranged geodetically above the series of printing cylinders, the printing module <NUM> has a drying unit <NUM>.

Additionally, the printing module <NUM> has two mounting positions for a blade beam <NUM>, wherein in the embodiment shown in <FIG> the blade beam <NUM> is a doctor chamber blade arranged for interaction with the first printing cylinder <NUM>.

In <FIG>, a sectional side view of the printing module <NUM> is shown.

From this depiction of the printing module <NUM>, it can be noted that the first printing cylinder <NUM>, the second printing cylinder <NUM> and the impression cylinder <NUM> are mounted to a machine frame <NUM> of the printing module <NUM>.

More precisely, the first printing cylinder <NUM> and the second printing cylinder <NUM> are coupled to support shafts <NUM> by means of a complementary coupling interface <NUM> at an end of the respective printing cylinder.

The support shafts <NUM> are further rotatorily held in the machine frame <NUM>.

The first printing cylinder <NUM> and the second printing cylinder <NUM> can be withdrawn from and inserted into the printing module <NUM> which is illustrated in <FIG>.

To this end, the support shafts <NUM> are uncoupled from the respective printing cylinders to be withdrawn and moved away from the printing cylinders along an L-shaped path as indicated by arrows in <FIG>.

This enables the first printing cylinder <NUM> and the second printing cylinder <NUM> to be removed from the printing module <NUM> by a printing tool handling unit <NUM>.

In the embodiment shown in <FIG>, the printing tool handling unit <NUM> is a wagon <NUM> which is manually operated by the operator <NUM>.

The wagon comprises a spacer element <NUM> for aligning the wagon <NUM> relative to the machine frame <NUM>.

Furthermore, the wagon <NUM> has a lifting platform <NUM> on which an alignment element <NUM> is located. The alignment element <NUM> is further connected to an end effector <NUM> which comprises coupling interface <NUM> with which the end effector <NUM> can be at least temporarily coupled to the complementary coupling interface <NUM> of the first printing cylinder <NUM> and the second printing cylinder <NUM>.

The alignment element <NUM> is movably mounted on the lifting platform <NUM> such that the end effector <NUM> can be suitably arranged for being coupled to the respective printing cylinder, as further illustrated by the dashed end effector 69a in <FIG>.

The procedure for switching the first printing cylinder <NUM> and the second printing cylinder <NUM> is therefore as follows: First, the first printing cylinder <NUM> and the second printing cylinder <NUM> are uncoupled from the support shafts <NUM>, followed by a movement of the support shafts <NUM> along an L-shaped path as shown in <FIG>. This enables access to the first printing cylinder <NUM> and the second printing cylinder <NUM> from a so-called operator side of the printing module <NUM>. Then, the operator <NUM> positions the wagon <NUM> in front of the machine frame <NUM>, especially by means of the spacer element <NUM>. This is followed by arranging the lifting platform <NUM> and the alignment element <NUM> such that the coupling interface <NUM> of the end effector <NUM> and the complementary coupling interface <NUM> of the first printing cylinder <NUM> are aligned to allow a temporary coupling of the first printing cylinder <NUM> and the end effector <NUM>. The end effector <NUM> is then retracted by means of a movement of the alignment element <NUM>, thereby withdrawing the first printing cylinder <NUM> from the printing module <NUM>. Afterwards, a new printing cylinder <NUM> is temporarily coupled to the end effector <NUM> and inserted into the printing module <NUM> by a reversed order of steps. The same procedure is then repeated for the second printing cylinder <NUM>.

Of course, both the first printing cylinder <NUM> and the second printing cylinder <NUM> can be withdrawn from the printing module <NUM> before inserting new printing cylinders or the second printing cylinder <NUM> can be exchanged before or at the same time as the first printing cylinder <NUM>.

This procedure can also be automated if the operation of the wagon <NUM> is not done by the operator <NUM> but is controlled in an automated manner, e.g. by a (not shown) central operating device of the printing assembly <NUM>.

The printing mode of the printing module <NUM> is defined by the kind of first printing cylinder <NUM> and second printing cylinder <NUM> installed in the printing module <NUM>, wherein the printing module <NUM> according to the invention can be in a flexographic printing mode or in a gravure printing mode.

In the flexographic printing mode, the first printing cylinder <NUM> especially is an anilox roll <NUM> and the second printing cylinder <NUM> is a plate cylinder <NUM>. Exemplary constructions of the anilox roll <NUM> are shown in <FIG> and exemplary constructions of the plate cylinder <NUM> are shown in <FIG>.

The anilox roll <NUM> comprises an anilox shaft <NUM> on which an anilox sleeve <NUM> is mounted. Optionally, the anilox sleeve <NUM> is coupled to the anilox shaft <NUM> by an anilox adapter <NUM> arranged between the anilox sleeve <NUM> and the anilox shaft <NUM> (see <FIG>).

Similarly, the plate cylinder <NUM> comprises a plate cylinder shaft <NUM> on which a plate cylinder sleeve <NUM> is mounted, with an optional plate cylinder adapter <NUM> mounted there between (see <FIG>).

The anilox adapter <NUM> and the plate cylinder adapter <NUM> allow to secure the anilox sleeve <NUM> and the plate cylinder sleeve <NUM>, respectively, e.g. pneumatically or hydraulically.

In the gravure printing mode, the first printing cylinder <NUM> especially is a gravure cylinder <NUM> and the second printing cylinder <NUM> is a pressure roller <NUM>. Exemplary constructions of the gravure cylinder <NUM> are shown in <FIG> and exemplary constructions of the pressure roller <NUM> are shown in <FIG>.

The gravure cylinder <NUM> can have a mere gravure cylinder shaft <NUM> or a gravure cylinder shaft <NUM> with a gravure cylinder sleeve <NUM> mounted thereon (see <FIG>).

Similarly, the pressure roller <NUM> can have a mere pressure roller shaft <NUM> or a pressure roller shaft <NUM> with a pressure roller sleeve <NUM> mounted thereon (see <FIG>).

With other words, the gravure cylinder <NUM> and/or the pressure roller <NUM> can be formed as a beam.

In <FIG>, an intermediate state for preparing the printing module <NUM> for the flexographic printing mode is shown for the case that a plate cylinder <NUM> as shown in <FIG> is used as second printing cylinder <NUM> and an anilox roll as shown in <FIG> is used as first printing cylinder <NUM>.

In the shown embodiment, the anilox shaft <NUM> and the plate cylinder shaft <NUM> have been already inserted in the printing module <NUM> by the printing tool handling unit <NUM>. Afterwards, the anilox sleeve <NUM> and the plate cylinder sleeve <NUM> are mounted on the anilox shaft <NUM> and the plate cylinder shaft <NUM>, respectively, by the operator <NUM>. Using sleeves for the anilox roll <NUM> and the plate cylinder <NUM> also allows for short set-up times between print jobs if the printing mode of the printing module <NUM> is not be changed.

As one skilled in the art will appreciate, the printing assembly <NUM> according to the invention also allows for inserting and withdrawing the first printing cylinder <NUM> and the second printing cylinder <NUM> without having to manually manipulate the respective sleeves, too. Also, instead of a manual exchange of the sleeves by the operator, the exchange can be automatically done by the printing tool handling unit <NUM>.

In <FIG>, an alternative embodiment of the printing tool handling unit <NUM> is shown. In this embodiment, the printing tool handling unit <NUM> comprises an arm <NUM> on which the end effector <NUM> with the coupling interface <NUM> is mounted.

The arm <NUM> is preferably a robot arm and the printing tool handling unit <NUM> is preferably operated automatically. This allows for a further reduction of the set-up time of the printing machine <NUM> and increases reproducibility and reliability of the procedure for inserting and withdrawing printing tools from the printing module <NUM>.

In the following, different printing modes of the printing module <NUM> are described in more detail.

In <FIG>, the printing module <NUM> is shown in a flexographic printing mode, in which an anilox roll <NUM> is used as first printing cylinder <NUM> and a plate cylinder <NUM> is used as second printing cylinder <NUM>.

For supplying ink to the anilox roll <NUM>, a doctor chamber blade is used as blade beam <NUM>, wherein the doctor chamber blade is arranged on the right hand side of the vertical axis in the perspective chosen in <FIG>.

The doctor chamber blade is supplied with ink from an ink supply module <NUM> of the printing assembly <NUM>, wherein the ink supply module <NUM> and the doctor chamber blade are fluidly connected by means of a (not shown) ink supply line and an ink connector <NUM>.

As indicated by arrows in <FIG>, the anilox roll <NUM> and the plate cylinder <NUM> are displaceable along the vertical central axis of the printing module <NUM> to ensure correct positioning and a sufficient pressure between the anilox roll <NUM> and the plate cylinder <NUM> as well as between the plate cylinder <NUM> and the impression cylinder <NUM>.

The chamber doctor blade is displaceable both parallel and perpendicular to the vertical central axis and is rotatable such that the chamber doctor blade can follow the movement of the anilox roll <NUM> and ensure sufficient contact for a consistent transfer of ink to the anilox roll <NUM>.

The ink tray <NUM> is in a rest position and has no contact with the anilox roll <NUM>.

In <FIG>, the course of the material web <NUM> is indicated by arrows wherein two different possible entry points are indicated by the arrows P<NUM> and P<NUM>, respectively. Which of these entry points are used, depends on the further components of the printing assembly <NUM>.

The material web <NUM> is guided by the guide rollers <NUM> to the impression cylinder <NUM> passing the tension sensing roller <NUM>. The impression cylinder <NUM> is also responsible for keeping the desired web tension.

The material web <NUM> is then passing the plate cylinder <NUM> such that ink is transferred from the plate cylinder <NUM> to the printing substrate <NUM> forming the material web <NUM>.

The ink is constantly supplied to the plate cylinder <NUM> by means of the anilox roll <NUM>.

After being printed upon, the material web <NUM> then enters the drying unit <NUM> from which it is passed to the temperature control roller <NUM> before leaving the printing module <NUM> towards further processing steps of the printing assembly <NUM>.

In <FIG>, an alternative flexographic printing mode of the printing module <NUM> is depicted, which essentially corresponds to the flexographic printing mode described above.

However, the blade beam <NUM> has been rearranged to the left hand side of the central vertical axis in the in the perspective chosen in <FIG> and the direction of rotation of the involved cylinders and rolls have been inverted according to the inverted path of the material web <NUM> which is essentially mirrored to the one shown in <FIG> based on two different possible entry points as highlighted by the arrows P<NUM> and P<NUM>, respectively.

The alternative flexographic printing mode allows printing on the backside of the material web <NUM> without any further changes to the printing assembly <NUM>.

The printing assembly <NUM> according to the invention allows for easily switching between the flexographic printing mode shown in <FIG> and the one shown in <FIG> by merely re-arranging the blade beam <NUM>.

Preferably, the position of the blade beam can be changed by interaction with the printing tool handling unit <NUM>, i.e. the blade beam <NUM> preferably comprises a coupling interface which is analogue to the complementary coupling interfaces <NUM> of the printing cylinders.

In <FIG>, the printing module <NUM> is shown in a gravure printing mode, in which a gravure cylinder <NUM> is used as first printing cylinder <NUM> and a pressure roller <NUM> is used as second printing cylinder <NUM>.

For constantly supplying ink to the gravure cylinder <NUM>, the ink tray <NUM> is in the operation position in which the fountain roller <NUM> of the ink tray <NUM> is in contact with the gravure cylinder <NUM>.

The ink tray <NUM> is supplied with ink from the ink supply module <NUM>, wherein the ink supply module <NUM> and the ink tray <NUM> are fluidly connected by means of the (not shown) ink supply line and the ink connector <NUM>.

As blade beam <NUM>, a squeegee is used in the shown embodiment of the gravure printing mode. The squeegee removes excess ink from the surface of the gravure cylinder <NUM>, i.e. ink which is not in depressions of the gravure cylinder <NUM>.

The squeegee is arranged on the right hand side of the vertical axis in the perspective chosen in <FIG>.

As indicated by arrows in <FIG>, the gravure cylinder <NUM> and the pressure roller <NUM> are displaceable along the vertical central axis of the printing module <NUM> to ensure correct positioning and a sufficient pressure between the gravure cylinder <NUM> and the pressure roller <NUM> as well as between the pressure roller <NUM> and the impression cylinder <NUM>.

The squeegee is displaceable both parallel and perpendicular to the vertical central axis and is rotatable such that the squeegee can follow the movement of the gravure cylinder <NUM> and ensure sufficient contact for a consistent removal of excess ink from the gravure cylinder <NUM>.

In <FIG>, the course of the material web <NUM> is indicated by arrows. As can be seen, the same possible entry points indicated by the arrows P<NUM> and P<NUM>, respectively, are used as for the flexographic printing mode as shown in <FIG>.

However, the course of the material web <NUM> is different in the gravure printing mode. The material web <NUM> is guided by the guide rollers <NUM> to the pressure sensing roller <NUM> to the impression cylinder <NUM> before passing the pressure roller <NUM> such that ink is transferred from the gravure cylinder <NUM> to the printing substrate <NUM> forming the material web <NUM>.

Therefore, in this embodiment of the gravure printing mode, the pressure roller <NUM> and not the impression cylinder <NUM> is responsible for keeping the desired web tension.

After being printed upon, the material web <NUM> enters the drying unit <NUM> from which it is passed to the temperature control roller <NUM> before leaving the printing module <NUM> towards further processing steps of the printing assembly <NUM>.

In <FIG>, an alternative gravure printing mode of the printing module <NUM> is depicted, which essentially corresponds to the gravure printing mode described above.

However, the blade beam <NUM> has been rearranged to the left hand side of the central vertical axis in the perspective chosen in <FIG> and the direction of rotation of the involved cylinders and rolls have been inverted according to the inverted path of the material web <NUM> which is essentially mirrored to the one shown in <FIG> based on two different possible entry points as highlighted by the arrows P<NUM> and P<NUM>, respectively.

The alternative gravure printing mode allows printing on the backside of the material web <NUM> without any further changes to the printing assembly <NUM>.

The printing assembly <NUM> according to the invention allows for easily switching between the gravure printing mode shown in <FIG> and the one shown in <FIG> by merely re-arranging the blade beam <NUM>.

In <FIG>, a further alternative flexographic printing mode is shown schematically.

In this flexographic printing mode, the type and arrangement of printing tools, i.e. of the blade beam <NUM> and of the printing cylinders, is equivalent to the arrangement shown in <FIG> and reference is made to the explanations above.

However, the course of the material web <NUM> is analogue to the one discussed in regard to the gravure printing mode as shown in <FIG>, i.e. printing on the backside of the material web <NUM>. With other words, the flexographic printing mode of <FIG> is a hybrid printing mode with the printing tools defining the flexographic printing mode but using an gravure printing mode course of the material web <NUM>.

From the above it becomes clear that the printing module <NUM> can be run in a highly flexible manner which facilitates the implementation of the printing module <NUM> in the printing assembly <NUM>.

In <FIG>, yet another alternative flexographic printing mode is shown schematically.

However, the course of the material web <NUM> is analogue to the one discussed in regard to the gravure printing mode as shown in <FIG>. With other words, the flexographic printing mode of <FIG> is a hybrid printing mode with the printing tools defining the flexographic printing mode but using a gravure printing mode course of the material web <NUM>.

In contrast to the flexographic printing mode of <FIG>, the arrangement as shown in <FIG> allows to print on the front side of the material web <NUM>.

Claim 1:
A printing assembly, comprising
a printing machine (<NUM>) with a printing module (<NUM>) having a flexographic printing mode and a gravure printing mode, wherein the printing module (<NUM>) comprises at least two printing cylinders (<NUM>, <NUM>) defining the printing mode of the printing module (<NUM>),
a printing tool handling unit (<NUM>) being configured for withdrawing and inserting the at least two printing cylinders (<NUM>, <NUM>) from and into the printing module (<NUM>), respectively,
wherein the printing tool handling unit (<NUM>) comprises a coupling interface (<NUM>) and the at least two printing cylinders (<NUM>, <NUM>) each comprise a complementary coupling interface (<NUM>) such that the printing tool handling unit (<NUM>) can at least temporarily be coupled to one or more of the at least two printing cylinders (<NUM>, <NUM>) via the respective coupling interfaces (<NUM>, <NUM>), and
wherein the coupling interface (<NUM>) provided on the printing tool handling unit (<NUM>) and each of the complementary coupling interfaces (<NUM>) provided on the at least two printing cylinders (<NUM>, <NUM>) are standardized such that the same coupling interface (<NUM>) provided on the printing tool handling unit (<NUM>) can be used to be coupled to the complementary coupling interface (<NUM>) of each of the at least two printing cylinders (<NUM>, <NUM>).