EP1740489B1

EP1740489B1 - Delivery unit for sheet-fed printing or processing machines

Info

Publication number: EP1740489B1
Application number: EP05718520A
Authority: EP
Inventors: Kurt Georg Nagler; Johannes Georg Schaede; Peter Eugen Wagner
Original assignee: KBA Giori SA
Current assignee: KBA Notasys SA
Priority date: 2004-04-22
Filing date: 2005-04-20
Publication date: 2008-08-06
Anticipated expiration: 2025-04-20
Also published as: WO2005102887A2; EP1990299A2; EP1990299A3; ATE403622T1; EP1740489A2; WO2005102887A3; DE602005008728D1

Abstract

There is described a delivery unit (20; 20') for coupling to a sheet printing or processing unit of a sheet-fed printing or processing machines comprising several delivery modules forming a plurality of delivery piles (21, 21.1 to 21.3, 21.1 to 21.5) disposed one after the other along a sheet delivery path, a transporting system (27, 27.1, 27.2, 27a, 27b) for transporting the sheets along the sheet delivery path, and sheet-delivery control means for selectively delivering the sheets in any one of the said delivery piles. The delivery modules are built in a modular fashion, each delivery module being constructed as an independent delivery module with individual sheet transfer means (211, 212, 218) for assisting transport of the sheets along the sheet delivery path and individual control means (215) for selective delivery of the sheets in the delivery pile of the delivery module, the delivery unit further comprising an adaptation unit (22) for adapting the delivery piles to the printing or processing unit. Each delivery module includes a pile conditioning device (217) for aligning sheets which are successively delivered to the delivery pile into a uniform pile of sheets, which pile conditioning device (217) is adjustable lengthwise and Widthwise to the dimensions of the sheets

Description

The present invention relates to a delivery unit for coupling to a sheet printing or processing unit of sheet-fed printing or processing machines.
Delivery units are known per se in the art of printing and processing machines. Usually, the known delivery units are limited to three delivery piles, one delivery pile for the sheets having a defect, and two delivery piles for the sheets which are considered meeting the determined quality requirements, i.e. "good" sheets. These two delivery piles are typically filled alternatively, one being filled with arriving successive sheets, and the other being emptied of piles of sheets.
Several examples of known delivery units are shown in figures 1A, 1B, 1C and 1D.
Figure 1A shows a delivery unit with three delivery piles 1, 2, 3. One delivery pile, for example delivery pile 1, receives sheets with a defect, and the two other delivery piles 2 and 3 receive sheets that are recognised as "good". Pallets present in each delivery pile 1, 2, 3 receive alternately successive sheets or sheets with defects. In the delivery unit of figure 1A, sheets are transported in a clockwise direction.
Figure 1B shows another configuration of delivery unit with three delivery piles 4, 5 and 6. Again, one delivery pile (delivery pile 4 for example) is used for sheets with a defect and the two other delivery piles (5, 6) are used for "good" sheets. One delivery pile (for example delivery pile 5) is being filled with successive printed sheets and, once full, the sheets are directed in the other delivery pile (for example pile 6) so that the pile of sheets formed in one delivery pile (pile 5 in this figure) can be taken away for subsequent treatment. In the delivery unit of figure 1B, sheets are also transported in a clockwise direction.
Figure 1C shows another configuration of delivery unit, also with three delivery piles 7, 8 and 9. In this delivery unit, drying means are provided (shown generally at 10) to dry the printed surface of the sheets before they are put in a delivery pile. In this delivery unit as represented, the delivery piles 7, 8 and 9 are built in the manner of a paternoster. In contrast to the previous configurations shown in figures 1A and 1B, sheets are transported in this case in a counter-clockwise direction.
Finally, figure 1D shows a further configuration of delivery unit, again with three delivery piles 11, 12, 13. As with the previous designs, one delivery pile (for example 11) is used for defective sheets and the other for "good" sheets. In this latter example, sheets are transported in a clockwise direction.
All these known delivery piles are limited in their use since they have a definite design and are not compatible with one another. Therefore, the buyer of printing machines is limited to certain configurations of delivery units.
A modular delivery unit is known from DE 198 19 491 C1 .
It is therefore an aim of the invention to improve the known delivery units of the prior art.
It is a further aim of the present invention to provide a delivery unit that can be customized and adapted to various needs.
It is another aim of the present invention to provide a delivery unit that can be used on several different machines.
To this effect, the invention complies with the definition of the claims.
The invention will be best understood with the description of an exemplary embodiment and of the accompanying drawings in which:

Figures 1A to 1D show delivery units of the prior art;
Figure 2 shows an embodiment of a delivery unit according to the invention in side cut;
Figure 3 shows a first example of a delivery unit configuration according to the invention;
Figure 4 shows another example of a delivery unit configuration according to the invention;
Figure 5 is a partial side view of the main functional components of the delivery unit of Figure 2;
Figure 6 is a partial side view of the driving unit of the lifting mechanism used to move piles of sheets upwards or downwards within a delivery module;
Figure 7 is a partial perspective view of an example of the gripper release device disposed in each delivery module for selectively releasing grippers of a gripper bar;
Figures 8A and 8B are partial cross-sectional views of a delivery module, taken respectively transversely to the direction of displacement of the sheets and along the direction of displacement of the sheets, in the vicinity of the location where sheets are delivered to the delivery pile;
Figure 9 is a partial perspective view of a suction roller used as a braking device for slowing-down the sheets that are to be delivered to the delivery pile;
Figure 10 is a top view of the location where the sheets are delivered to the delivery pile; and
Figure 11 is a schematic top view of a sheet guiding drum used to guide the sheets at an upstream location in each delivery module.

In figure 2, an example of a modular delivery unit 20 is shown with three successive identical delivery piles 21.1, 21.2 and 21.3 disposed one after the other along a sheet delivery path (which goes from right to left in the example of figure 2). In the configuration illustrated in figure 2, printed or processed sheets are carried through the various delivery piles 21.1 to 21.3 by a sheet transporting system which transports the sheets from an upstream-located printing or processing unit (not shown in figure 2) In figure 2, delivery pile 21.1 is defined as the "first pile" along the sheet delivery path, and delivery piles 21.2 and 21.3 as the "second pile" and "third pile" respectively.
The delivery piles 21.1 to 21.3 are built in a modular fashion, each delivery pile being generally identical to the other delivery piles. More particularly, each delivery pile is constructed as an independent delivery module with individual sheet transfer sections for assisting the transport of the sheets along the sheet delivery path (e.g. sheets guides, sheet guiding drum, etc.) and individual control means for the selective delivery of the sheets in the delivery pile (e.g. gripper control, aspiration rolls, etc.). Each delivery module is further provided with its own pile handling system for handling the sheets that are piled in the delivery pile (e.g. a pile lifting mechanism, a pile condition mechanism, etc.). In the configuration shown in figure 2, pallets 25 are for instance disposed in the delivery piles for supporting the pile of sheets (designated by references 24.1 to 24.3) and these pallets 25 can be driven downwards or upwards by a lifting mechanism integrated in each of the delivery modules which will be briefly described hereinafter. Each delivery module further comprises a pile conditioning mechanism, the purpose of which is to properly align each delivered sheet one on top of the others so as to form a straight uniform pile. The adaptation to the format of the paper may also be adjustable.
The delivery unit 20 further comprises an adaptation unit 22 which builds an interface with the printing or processing unit (not illustrated but located upstream, on the right-hand side of the delivery unit illustrated in figure 2). This adaptation unit 22 may advantageously comprise drying means 22.5, such as a UV drier, for drying freshly printed sheets leaving a printing unit.
As schematically illustrated in figure 2, all delivery modules 21.1 to 21.3 share a generally common configuration with upstream and downstream coupling sections designed in such a manner that successive delivery modules are coupled one after the other along the sheet delivery path through direct coupling of the corresponding downstream and upstream coupling sections of the successive delivery modules. In this particular example, the second delivery module 21.2 is coupled by its upstream coupling section to the downstream coupling section of the first delivery module 21.1 and by its downstream coupling section to the upstream coupling section of the third delivery module 21.3. Similarly, the upstream coupling section of the first delivery module 21.1 is coupled to a corresponding coupling section of the adaptation unit 22. By constructing each delivery module in the manner described hereabove, one basically has not limitation as regards the number of delivery modules that can be connected one after the other. The only real limitation is the overall length of the delivery unit as well as the length of the sheet transporting path. A starting configuration will preferably include at least three delivery modules, the number thereof being easily extendable to up to seven delivery piles or more.
The sheet transporting system for carrying the sheets to the various delivery piles is an endless chain gripper system known per se in the art, the transporting path of which is designated globally by reference 27 in figure 2. Such an endless chain gripper system comprises two endless chains - indicated by reference numerals 27.1, 27.2 in the drawings - (not illustrated in figure 2) located on each side of the printing or processing machine and a plurality of spaced-apart gripper bars coupled to each of the endless chains which carry a plurality of grippers (located transversely to the direction of transport of the sheets) for holding a leading edge of a sheet.
The path of the endless chain gripper system may vary depending on the overall machine configuration but at least one portion of the path goes from the printing or processing unit through the delivery modules and defines the so-called "sheet-delivery path". The remaining part of the transporting path which returns from the last one of the delivery modules to the printing or processing unit defines the so-called "returning path".
As schematically illustrated in figure 2, the endless chain gripper system is designed so that lower and upper chain paths 27a, 27b are both located in an upper section of each delivery module, this being more advantageous in terms of overall size and length of the sheet transport system. In this example, the delivery unit thus further comprises a reversing module 23 coupled to the delivery module which is the farthest away from the printing or processing unit (namely delivery module 21.3 in figure 2) for connecting both paths of the chain gripper system.
In the configuration shown in figure 2, it is assumed that sheets are transported by the sheet transport system in a clockwise direction, i.e. the sheets are transported to the delivery piles along the lower chain path 27a and, following delivery of the sheets, the grippers bars are returned to the printing or processing unit along the upper chain path 27b. In this case, the so-called sheet delivery path will be defined by the portion of the sheet transporting system which runs from the printing or processing unit until the output of the last delivery module, i.e. module 21.3, and the returning path will be defined by the remaining portion which runs from the reversing module 23, through the delivery modules 21.3 to 21.1, back to the printing or processing unit.
Alternatively, the sheets may be transported in a counter-clockwise direction, the sheets being first transported through the delivery modules 21.1 to 21.3 along the upper chain path 27b, reversed by the reversing module 23 and thereafter transported again through the delivery modules 21.3, 21.2 and 21.1 where they are selectively delivered. In this case, delivery module 21.3 will be considered as the "first pile" along the sheet delivery path, whereas delivery module 21.1 will be considered as the "last pile". In contrast to the previous situation, the sheet delivery path will encompass the upper chain path 27b and the portion of the lower chain path 27a running from the reversing module 23 to the adaptation unit 22, and the returning path as such will be defined by the portion running from the output of the last delivery module along the sheet delivery path, namely module 21.1 in this case, back to the printing or processing unit.
In both cases, it shall be understood that, when sheets which are printed on one side are to be delivered to the delivery unit 20, the freshly printed side of the sheets will preferably be directed upwards at the location were they are delivered to the delivery piles (i.e. the printed side is directed upwards in the region where the sheets are transported along the lower chain path 27a of the chain gripper system).
Figure 3 is a side view of the delivery unit of figure 2. The same references are used to designate the same components of the delivery unit 20. In figure 3, the last delivery pile 21.3 is full and contains a pallet 25 carrying a continuous pile of sheets 24.3 and can be taken away while, for instance, another pile of sheets 24.2 is accumulated onto the pallet 25 located in the second delivery pile 21.2 and delivery pile 21.1 is used as the delivery pile for the sheets with a defect. It shall be understood that the specific attribution of the delivery piles (e.g. for receiving sheets carrying a defect or "good" sheets) may be selected by the user. As schematically illustrated in figure 3, each delivery module is preferably provided with its own control panel 31, 32, 33 for controlling and adjusting the parameters of each delivery module. Another control panel 30 might be provided, for example on the adaptation unit 22 where the user can select or adjust the parameters of the whole delivery unit.
Figure 4 shows a side view of another possible configuration of a delivery unit 20' which illustrates the modularity of the delivery unit according to the invention as well as various possible systems for piling sheets. In the example of figure 4, the delivery unit 20' comprises five delivery modules 21.1 to 21.5, again with their individual control panels 31 to 35.
In the first delivery pile 21.1, there is a so-called "Euro-pallet" 25 similar to those illustrated in figures 2 and 3.
In the second delivery pile 21.2, there is a trolly 40 on which the sheets are piled.
In the third delivery pile 21.3, the sheets are piled on a piling table 41.
In the fourth delivery pile 21.4, the sheets are piled in a paternoster system 42, i.e. a piling system with a plurality of superimposed pile carriers for carrying a definite number of sheets.
In the fifth delivery pile 21.5, there is shown a pallet 25 carrying a plurality of superimposed security pallets 43 that cover the piles of sheets to avoid the risk of sheets being taken away.
Figure 5 is a schematic side view of the delivery unit of figure 2 (only one delivery module, designated by reference 21, being illustrated in this figure) which highlights the main functional components of the delivery unit.
Starting with the sheet transporting system, each delivery module 21 includes pairs of chain guides 211, 212 secured to the side panels, i.e. one pair for the lower chain path 27a and one pair for the upper chain path 27b, on each side of the delivery module. Similarly, the adaptation unit 22 includes two pairs of chain guides 221, 222 for the lower and upper chain paths. Just one of the gripper bars 270 guided in chain guide 221 of the adaptation unit 22 is shown for the purpose of illustration in figure 5. The reversing module 23 on the other hand comprises a pair of chain wheels 235, located on each side of the module, which cooperate with the first and second endless chains (27.1, 27.2 as shown in fig 7, 8A, 8B) of the chain gripper system. Advantageously, the location of the two chain wheels 235 in the reversing module 23 is adjustable so as to adapt the tension in the endless chains. This can be achieved by mounting the chain wheels 235 on guiding rails 236 located on each side of the reversing module 23.
As already mentioned, each delivery module 21 includes its own pile lifting mechanism 213 which will briefly be described in connection with figure 6. A pile carrying board 214 driven by this pile lifting mechanism is schematically illustrated in figure 5.
Each delivery pile further comprises a gripper release control device 215 for selectively releasing the grippers of a gripper bar which holds a sheet to be delivered to the delivery pile (see also figure 7).
A suction assembly 216 acting as a braking device for slowing down the sheets to be delivered in the delivery pile is disposed in each delivery module at an upstream location along the delivery path, below the sheet delivery path (see also figures 8b, 9 and 10.
The pile conditioning mechanism is designated globally by reference numeral 217 in figure 5 (see also figures 8a and 8b).
Lastly, reference numeral 218 designates a sheet guiding drum which is located in each delivery module shortly upstream of the suction assembly 216, on an upper side of the sheet delivery path (see also figures 8b and 11).
Referring to figure 6, there is disclosed schematically the mechanism 213 for the vertical displacement of the piles of sheets within each delivery pile. This mechanism basically comprises a driving unit 213.1 which drives two shafts 213.2 and 213.3 located on each side of the delivery pile (in vertical supporting parts of the delivery module) each through a chain and wheel arrangement 213.4, 213.5. The rotational movement of the shafts 213.2 and 213.3 is converted into a linear downward/upward movement by two guiding systems (not illustrated) located in the vertical supporting parts of the delivery module, a bottom end of the guiding systems being coupled to the board or pallet which is intended to receive the sheets (e.g. pallet 23 in figure 2 or carrying plate 214 in figure 5).
Turning now to figure 7, the gripper release control device 215 will be described in greater detail. The gripper release control device 215 comprises a gripper cam 215.1 which cooperates with a gripper releasing arm 276 provided on each gripper bar 270. The releasing arm 276 has a contacting roller 277 which, when the gripper release control device 215 is triggered for delivery of a sheet in the delivery pile, rolls on the contacting surface of the gripper cam 215.1 and causes the release of the grippers 275 on the gripper bar 270, thereby freeing the sheet held by the gripper bar 270 (the sheet transporting direction is indicated by the arrow in figure 7).
The gripper release control device 215 is actuated by a gripper cam actuating mechanism having an eccentric bush 215.2 driven by a pneumatic cylinder 215.3. When triggered, the eccentric bush 215.2 is rotated by the pneumatic cylinder 215.3 thereby causing a lowering of the gripper cam 215.1 onto the trajectory of the releasing arm 276 of the next gripper bar 270 so as to release the corresponding sheet in the delivery pile. When the gripper release control device is not triggered, the releasing arm 276 does not get into contact with the gripper cam 215.1 which remains in a lifted position.
As shown in figure 7, the gripper release control device 215 may further comprise an adjustment mechanism for adjusting the amount of displacement of the gripper cam (and thereby act on the timing of the releasing of the sheets. In the example of figure 7, this adjustment mechanism takes the form of a second eccentric bush 215.4 which acts on the position of one end of the actuating arm of the gripper cam actuating mechanism 215.1. The second eccentric bush 215.4 is advantageously actuated by means of a linear drive 215.5 integrated to the gripper release control device.
Referring to figures 8A and 8B, one will now describe in greater detail the pile conditioning mechanism 217. As illustrated in the figures, the pile conditioning mechanism 217 is located below the sheet releasing location (i.e. slightly underneath the lower chain path 27a) and includes primarily a front stop 217.1 and two lateral adjustable stops 217.2 and 217.3. A further stop 217.4 (not illustrated in figures 8A and 8B) is disposed at the trailing end of the sheets (as this will be seen hereinafter), this rear stop 217.4 is secured to the suction assembly 216 and is also adjustable (in the longitudinal direction).
The purpose of the front stop 217.1 is to provide an obstacle to stop the sheets that are delivered to the delivery pile. This front stop 217.1 further defines a front reference for the alignment of the sheets into a pile. This front stop 217.1 is basically constructed as a plate 217.10 disposed essentially vertically at the front of the delivery location and further comprises a plurality of movable finger elements 217.11 the surfaces of which are flush with the surface of the vertical plate 217.10 and can rotate in the vertical plane to compensate (to some extent) for the changing pile height and ensure that at least a certain number of sheets on top of the pile remain in contact with the front stop throughout the piling process.
The lateral stops 217.2 and 217.3 are constructed in a similar fashion (with vertical plates 217.20/217.30 and movable finger elements 217.21/217.31) and are located on each side of the pile to form lateral references for the pile. In this example, both lateral stops 217.2 and 217.3 are adjustable to the paper format and can thus each move transversely to the direction of displacement of the sheets (using a linear actuating mechanism 217.25, 217.35 actuated pneumatically - see also figure 10).
In order to assist the delivery of the sheets into the delivery pile (and ensure that the sheets fall properly onto the pile), the pile conditioning mechanism is further provided with a blowing device 217.5 located between the lower and upper chain paths 27a, 27b. The blowing device 217.5 comprises a plurality of blowing pipes 217.50 for blowing air onto the upper side of the sheets. Preferably, blowing pipes are arranged lengthwise along the direction of displacement of the sheets (see also figure 10) as well as transversely along the leading edge of the sheet that is to be delivered (not illustrated in figure 8A and 8B). The blowing pipe on the leading edge ensures that the sheet does not fold on itself during the period where the sheet freely falls onto the pile.
In figure 8B, the suction assembly 216 and associated sheet guiding drum 218 is schematically illustrated. As already mentioned, both elements are located upstream along the sheet delivery path. As illustrated, a sheet S held by a gripper bar 270 gets into contact both with the suction assembly 216 and the sheet guiding drum 218, respectively on the lower and upper side of the sheet S.
The suction assembly 216 is illustrated in greater detail in figure 9. It mainly consists of a suction roller having a drive shaft 216.1 driven into rotation by a drive unit 216.2 and which carries a plurality of cylindrical suction units 216.3 distributed axially along the drive shaft 216.1. The provision of a separate drive unit 216.2 for driving the suction units 216.3 into rotation allows for an independent adjustment of the rotational speed of the suction units and thereby the amount of braking effect generated by the suction assembly 216 on the sheet to be slowed-down. Guide plates 216.4 are further provided axially along the suction assembly 216 in order to properly guide the sheets over the surface of the suction assembly 216.
As already mentioned hereinabove, the rear stop 217.4 (which is again provided with movable vertical finger elements 217.41) is fixedly secured to the frame of the suction assembly 216. The whole assembly is preferably mounted in the delivery module so as to be movable longitudinally (along the direction of displacement of the sheets). To this end, the assembly is mounted onto rails and a driving mechanism 216.5 with a drive unit (not shown) ensures selective displacement of the assembly along the rails.
Figure 10 is a top view of the delivery location showing how the front stop 217.1, lateral stops 217.2, 217.3, blowing pipes 217.50 and suction assembly 216 (with the rear stop 217.4) are disposed with respect to a sheet being delivered to the delivery pile. In the figure, one can further notice a plurality of stop cocks 216.8 for turning off the corresponding suction units when processing narrow sheets which do not cover the entire surface of the suction assembly (this for maintaining the full suction effect on the sheets).
Reference is now made to Figure 11 which shows a top view of the sheet guiding drum 218. This sheet guiding drum 218 mainly consists of a shaft 218.1 bearing a plurality of spaced-apart supporting discs 218.2. The supporting discs 218.2 are disposed axially along the shaft 218.1 at locations such that they enter into contact with unprinted regions of the sheets S. As shown in figure 11, in the security printing field, the sheets delivered to the delivery unit commonly comprise each an array of prints arranged in rows and columns. The supporting discs 218.2 of the sheet guiding drum 218 may thus be disposed so that they do not spoil the printed surface of the sheets and only get in contact with the sheets at intermediate location between the columns of prints. It shall further be appreciated that each supporting disc exhibits an aperture on its periphery, as illustrated in figures 5, 8B, which is synchronized with the displacement of the gripper bars 270.
Of course, safety devices (such as sensors) may be added to stop the machine if a person enters a delivery pile or in case of a problem (jamming) etc. In addition, photo-sensing devices may be located into each of the delivery modules (and adaptation unit) in order to monitor the number of sheets being delivered to the delivery unit. Figure 5 for instance shows a supporting arm 219 mounted in the delivery module 21 and extending into the adaptation unit and which carries on its end a photo-sensor for counting the sheets.

Claims

Delivery unit (20; 20') for coupling to a sheet printing or processing unit of a sheet-fed printing or processing machine comprising several delivery modules forming a plurality of delivery piles (21, 21.1 to 21.3, 21.1 to 21.5) disposed one after the other along a sheet delivery path, a transporting system (27, 27.1, 27.2, 27a, 27b) for transporting the sheets along the sheet delivery path, and sheet-delivery control means for selectively delivering the sheets in any one of the said delivery piles, said transporting system being an endless chain gripper system (27, 27a, 27b) with first and second endless chains (27.1, 27.2) and a plurality of spaced-apart gripper bars (270) coupled to the first and second endless chains (27.1, 27.2), each gripper bar (270) carrying a plurality of grippers (275) for holding a leading edge of a sheet (S), said endless chain gripper system (27, 27a, 27b) having a first, path going from the sheet processing or printing unit through said delivery modules, which first path defines said sheet delivery path, and a second path returning from the delivery modules to the printing or processing unit, both said first and second paths passing through an upper section of each delivery module,
wherein said delivery modules are built in a modular fashion, each delivery module being constructed as an independent delivery module with individual sheet transfer means (211, 212, 218) for assisting transport of the sheets along the sheet delivery path and individual control means (215) for selective delivery of the sheets in the delivery pile of the delivery module, and wherein said delivery unit further comprises an adaptation unit (22) for adapting the delivery modules (21, 21.1 to 21.3, 21.1 to 21.5) to the printing or processing unit and a reversing module (23) coupled to the last delivery module of the delivery unit (21.3; 21.5) for connecting said first and second path of the endless chain gripper system,
and wherein said delivery modules all share a generally common configuration with upstream and downstream coupling sections designed in such a manner that first and second successive delivery modules are coupled one after the other along the sheet delivery path through direct coupling of the downstream coupling section of the first delivery module with the upstream coupling section of the second delivery module.
Delivery unit as defined in claim 1, wherein each delivery module further comprises a gripper release control device (215) for selectively releasing the grippers (275) of a gripper bar (270) which holds a sheet which is to be delivered to the delivery pile.
Delivery unit as defined in claim 2, wherein said gripper release control device (215) comprises a gripper cam (215.1) that is selectively displaceable onto the trajectory of a gripper releasing arm (276) of said gripper bars (270) to release the grippers (275) holding a sheet to be delivered in the delivery pile.
Delivery unit as defined in any one of the preceding claims, wherein each delivery module further comprises at least one pair of chain guiding rails (211, 212) for guiding said first and second endless chains (27.1, 27.2) through the delivery module.
Delivery unit as defined in any one of the preceding claims, wherein said reversing module (23) includes a pair of chain wheels (235) for driving said first and second endless chains (27.1, 27.2) in the reversing module.
Delivery unit as defined in claim 5, wherein a location of said chain wheels (235) in said reversing module (23) is adjustable so as to adapt the tension in said first and second endless chains (27.1, 27,2).
Delivery unit as defined in any one of the preceding claims, wherein each delivery module further comprises a sheet guiding drum (218) disposed at an upstream location along the sheet delivery path for guiding the sheets when they enter the delivery module.
Delivery unit as defined in claim 7, wherein said sheet guiding drum (218) includes a shaft (218.1) with a plurality of supporting discs (218.2) distributed axially along the shaft, each supporting disc being disposed axially along the shaft at a location such that the supporting disc enters into contact with unprinted regions of the sheets (S).
Delivery unit as defined in any one of the preceding claims, wherein each delivery module further comprises a braking device (216) for selectively slowing down a sheet (S) which is to be delivered to the delivery pile.
Delivery unit as defined in claim 9, wherein said braking device (216) includes a suction roller disposed transversely with respect to the sheet delivery path for acting on a lower side of the sheets to be delivered to the delivery pile.
Delivery unit as defined in claim 10, wherein said suction rollers includes a drive shaft (216.1) coupled to a drive unit (216.2) and a plurality of axially-distributed suction units (216.3) which are rotatably coupled to the drive shaft.
Delivery unit as defined in any one of claims 9 to 11,
wherein a braking effect of each braking device (216) is adjustable independently for each delivery module.
Delivery unit as defined in any one of the preceding claims, wherein each delivery module further includes a pile lifting mechanism (213) for selectively driving up or down the sheets of the delivery pile.
Delivery unit as defined in any one of the preceding claims, wherein each delivery module includes a pile conditioning device (217) for aligning sheets which are successively delivered to the delivery pile into a uniform pile of sheets.
Delivery unit as defined in claim 14, wherein said pile conditioning device is adjustable lengthwise and/or widthwise to the dimensions of the sheets.
Delivery unit as defined in any one of the preceding claims, wherein each delivery module further comprises a photo-sensor for counting the number of sheets delivered to the delivery pile.
Delivery unit as defined in any one of the preceding claims, wherein each delivery module further comprises a blowing device (217.5) for blowing air onto an upper side of a sheet to be delivered to the delivery pile.
Delivery unit as claimed in any one of the preceding claims, comprising up to seven delivery modules.
Delivery unit as defined in any one of the preceding claims, wherein at least one delivery module comprises security pallets covering the sheets.
Delivery unit as defined in any one of the preceding claims, wherein at least one delivery module comprises a paternoster system.
Delivery unit as defined in any one of the preceding claims, wherein at least one delivery module comprises a piling table
Delivery unit as defined in any one of the preceding claims, wherein at least one delivery module comprises a trolly on which the sheets are piled.
Delivery unit as defined in any one of the preceding claims, wherein said adaptation unit (22) accommodates a drying unit (22.5), such as UV-drier, for drying freshly printed sheets transported by said sheet transport system.