DE102021118475B4 - Suction belt table for horizontal transport of individual sheet-shaped substrates in a conveyor level - Google Patents

Abstract

Suction belt table (19) for the horizontal transport of individual sheet-shaped substrates in a conveying plane (E19), characterized in that the suction belt table (19) has a catching device (58) and at least one skid belt (48), the catching device (58) and the at least one Ski jump conveyor (48), each controlled by a control unit (71), is designed to assume one of two different operating states, the first operating state being an inactive operating state and the second operating state being an activated operating state, the safety device (58) being in its activated state at least has a stop surface (66) for substrates to be caught, which is set up perpendicular to the conveying plane (E19) of the suction belt table (19), the at least one skid belt (48) extending in the transport direction (T) of the substrates by at least one in the transport direction (T) of the substrates extending substrate length is arranged in front of the at least one stop surface (66) set up perpendicular to the conveying plane (E19) of the suction belt table (19), the at least one skid belt (48) in its activated state with its end directed in the transport direction (T) of the substrates in one The acute angle opening in the transport direction (T) of the substrates is pivoted obliquely upwards out of the conveying plane (E19) of the suction belt table (19).

Description

The invention relates to a suction belt table for the horizontal transport of individual sheet-shaped substrates in a conveyor plane according to the preamble of claim 1.

The suction belt table described here below is a machine unit for use in a machine arrangement for processing sheet-shaped substrates (referred to as sheets for short), such a machine arrangement having a plurality of machine units arranged one after the other in the transport direction of the sheets. At least two of these machine units each have the transport devices that transport sheets. A suction belt table is used to transport processed sheets or sheets to be processed along a linear transport route in the machine arrangement in question, with these sheets being transported individually lying on at least one conveyor belt. While they are resting on the at least one conveyor belt, the individual sheets are each subjected to a suction force, i.e. H. held frictionally or non-positively on the conveyor belt in question by a holding force caused by a suction flow. The suction force is usually realized by a negative pressure acting on the respective arch, which is set in relation to the surrounding barometric air pressure by means of a suction device.

In a preferred use, the suction belt table is arranged in a sheet processing machine arrangement in the transport direction of the sheets after a dryer that dries the sheets. In a further development, the dryer is initially followed by a cooling section for air conditioning and/or conditioning of the sheets heated in the dryer, so that the suction belt table is only arranged after the cooling section.

A machine arrangement of the aforementioned type, be it with or without a cooling section after the dryer, usually has several processing stations arranged one behind the other in the transport direction of the sheets, each of which acts on the sheets, each of these processing stations z. B. is designed as a machine unit in this sheet processing machine arrangement. The suction belt table can - as mentioned - be arranged immediately after the dryer, so that no further processing station is arranged between the dryer mentioned and the suction belt table, or only after the cooling section formed after the dryer. In the machine arrangement used here as a preferred embodiment, at least the transport device of the dryer arranged upstream of the suction belt table or the associated cooling section is designed as a transport device which transports the sheets lying horizontally along a linear transport route. The dryer is therefore designed in particular as a continuous dryer for sheets in individual layers.

A further transport device, which is arranged downstream of the suction belt table in the transport direction of the sheets, is designed as a transport device which transports the sheets along a curved, in particular circular-arc-shaped transport route. This further transport device is preferably arranged immediately after the suction belt table, i.e. H. There is no further processing station arranged in the machine arrangement in question between the suction belt table and the downstream transport device. The sheets to be transported by this machine arrangement thus change after leaving the suction belt table from a linear transport path to a curved, in particular circular arc-shaped, transport path. As can be seen below, changing from a linear transport route to a curved, in particular circular arc-shaped transport route on a suction belt table is sometimes very problematic.

Through the DE 10 2016 207 397 A1 a sheet processing machine arrangement is known with a suction belt table arranged after a dryer that dries the sheets.

Through the DE 601 19 405 T2 A sheet output unit is known with the following features: a paper-receiving tray; a transfer passage for transferring a sheet of pretreated paper to the paper receiving tray along a sheet transfer direction; guide holes formed on both sides of the transfer passage; a transfer member located in the transfer passage for transmitting a force to the sheet of pretreated paper to move the sheet of pretreated paper in the sheet transfer direction; jump wings disposed in the guide openings and having convex and concave portions arranged alternately in a direction substantially perpendicular to the sheet transfer direction, such that the convex segments guide the sheet of pretreated paper and the concave recesses are out of contact with the sheet of pretreated paper; and an actuator that operates the jumping wings between a guiding position in which the jumping wings each protrude upwardly from the guiding openings and a waiting position in which the jumping wings are respectively retracted into the guiding openings, each of the convex segments being substantially inward extends the sheet transfer direction, and is angled either outwardly or inwardly therefrom by a given angle with respect to the sheet transfer direction, toward the downstream side of the sheet transfer direction.

The invention is based on the object of creating a suction belt table for the horizontal transport of individual sheet-shaped substrates in a conveyor plane.

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

The advantages that can be achieved with the invention are, in particular, that sheets can be caught and stacked on the suction belt table with the catching device before they are transferred to a transport device arranged downstream of the suction belt table. Further advantages can be seen from the following description.

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

• 1 einen Saugbändertisch in einer Bogen bearbeitenden Maschinenanordnung;
• 2 eine Seitenansicht des Saugbändertisches gemäß 1;
• 3 eine Draufansicht des in der 2 dargestellten Saugbändertisches;
• 4 eine Seitenansicht einer in den Saugbändertisch integrierten Fangeinrichtung;
• 5 die Fangeinrichtung der 4 in ihrer Parkposition;
• 6 die Fangeinrichtung der 4 in ihrer Fangposition;
• 7 einen Ausschnitt aus der 2 mit der Fangeinrichtung in ihrer Fangposition;
• 8 eine pneumatische Schaltung für den Betrieb der Fangeinrichtung;
• 9 ein Diagramm zum Hub des Zylinderkolbens eines die Fangeinrichtung antreibenden Pneumatikzylinders;
• 10 ein Diagramm zur Geschwindigkeit des Zylinderkolbens beim Betrieb der Fangeinrichtung;
• 11 ein Diagramm zur Beschleunigung des Zylinderkolbens beim Betrieb der Fangeinrichtung;
• 12 ein Diagramm zum Verlauf der Kolbenkraft des Zylinderkolbens beim Betrieb der Fangeinrichtung;
• 13 eine schematische Darstellung einer Schaltung zur Aufhebung eines Reibschlusses bzw. Kraftschlusses von auf dem Saugbändertisch gehaltenen Bogen;
• 14 einen Ausschnitt aus dem in der 3 in einer Draufsicht dargestellten Saugbändertisch;
• 15 eine Leiteinrichtung zwischen zwei in Transportrichtung der Bogen nacheinander angeordneten Transportbändern;
• 16 eine Ausgangssituation für die Funktion der Leiteinrichtung;
• 17 die Leiteinrichtung zu Beginn ihrer Aktivierung;
• 18 die aktivierte Leiteinrichtung;
• 19 die Leiteinrichtung bei der Übernahme eines Bogens;
• 20 einen Ausschnitt aus der in der 3 dargestellten Draufsicht auf den Saugbändertisch mit einer Düsenanordnung;
• 21 einen Ausschnitt aus der in der 2 dargestellten Seitenansicht des Saugbändertisches.

Show it:

• 1 a suction belt table in a sheet processing machine arrangement;
• 2 a side view of the suction belt table according to 1 ;
• 3 a top view of the in the 2 shown suction belt table;
• 4 a side view of a catching device integrated into the suction belt table;
• 5 the catching device 4 in their parking position;
• 6 the catching device 4 in their catching position;
• 7 an excerpt from the 2 with the safety gear in its catching position;
• 8th a pneumatic circuit for operating the safety gear;
• 9 a diagram of the stroke of the cylinder piston of a pneumatic cylinder driving the safety gear;
• 10 a diagram of the speed of the cylinder piston during operation of the safety gear;
• 11 a diagram of the acceleration of the cylinder piston during operation of the safety gear;
• 12 a diagram of the course of the piston force of the cylinder piston during operation of the safety gear;
• 13 a schematic representation of a circuit for canceling a frictional connection or non-positive connection of sheets held on the suction belt table;
• 14 an excerpt from the one in the 3 suction belt table shown in a top view;
• 15 a guide device between two conveyor belts arranged one after the other in the transport direction of the sheets;
• 16 an initial situation for the function of the control device;
• 17 the guidance device at the beginning of its activation;
• 18 the activated guidance device;
• 19 the guiding device when taking over a sheet;
• 20 an excerpt from the in the 3 illustrated top view of the suction belt table with a nozzle arrangement;
• 21 an excerpt from the in the 2 shown side view of the suction belt table.

An example of the machine arrangement mentioned at the beginning is in the 1 shown. Such a machine arrangement is e.g. B. from the one mentioned DE 10 2016 207 397 A1 known. The sheet processing machine arrangement chosen as an example, viewed in the transport direction T of the sheets, initially has a sheet feeder 01, in which a first stack 02 of sheets is ready for processing. The sheets are preferably rectangular substrates made of paper, cardboard or cardboard. Paper, cardboard and cardboard differ in their respective grammage, ie the weight in grams for one square meter of these sheets. Paper has a basis weight between 30 g/m ² and 150 g/m ² , cardboard has a basis weight between 150 g/m ² and 600 g/m ² and cardboard has a basis weight of more than 600 g/m ² . However, the sheets can also each be designed as a substrate made of plastic and/or as a thin panel. The sheet feeder 01 can also be designed as a magazine feeder having several first stacks 02.

A suction head 03 grabs each of the stacked sheets one after the other from above and guides these sheets z. B. by means of a first swing gripper 04 and optionally a transfer drum 34 cooperating with the first swing gripper 04 in a sequence of sheets separated from one another, e.g. B. a first coating device 05, this first coating device 05 z. B. is designed as a primer application device. The first coating device 05 has a z. B. designed as a printing cylinder transport cylinder 06 and z. B. a printing cylinder 07 cooperating with this transport cylinder 06 with an applicator roller 08 that is attached or at least adjustable to this printing cylinder 07, preferably in the form of an anilox roller, with at least one doctor blade in the axial direction of the applicator roller 08 for optimal dosage of a coating material to be applied to the surface of the sheets 09 or a chamber doctor system 09 extends. The transport cylinder 06 transports the sheets held on its lateral surface along a curved, in particular circular arc-shaped transport path. The first coating device 05 carries the coating material, e.g. B. a primer either over the entire surface or only at certain, ie at previously determined locations, ie partially. The sheets are then transported from the transport cylinder 06 of the first coating device 05, for example. B. by means of a first gripper system 11, in particular a first chain conveyor, and z. B. at least a first conveyor belt 12 to a non-impact printing device 13, whereby the first gripper system 11 and the first conveyor belt 12 cooperate when transferring the sheets to the non-impact printing device 13, in such a way that the first gripper system 11 delivers the sheets to the first conveyor belt 12, which has a linear transport path, with the sheets being transferred to the non-impact printing device 13 from the first conveyor belt 12. The first conveyor belt 12 is preferably designed as a revolving endless belt. In an advantageous embodiment, a first dryer 14 which dries the sheets coated in the first coating device 05 is provided in the area of the first gripper system 11, this dryer 14 z. B. is designed as a hot air dryer and / or as a dryer that dries by IR radiation or by UV radiation.

The non-impact printing device 13 usually has at least four inkjet printing devices that can be controlled independently of one another, each of these inkjet printing devices having a different printing color on the z. B. previously coated side of the sheet in the first coating device 05. In the machine arrangement described here as an example, the non-impact printing device 13 preferably has a second conveyor belt 16, so that the sheets are printed by the inkjet printing devices while they rest on this second conveyor belt 16. The second conveyor belt 16 is preferably designed as a revolving endless belt. In the transport direction T of the sheets, a second dryer 17 which dries the printed sheets is arranged after the non-impact printing device 13, this second dryer 17 also being z. B. is designed as a hot air dryer and / or as a dryer that dries by IR radiation or by UV radiation. The second dryer 17 has a transport device 18 which transports the sheets horizontally in a translational manner, ie along a linear transport path. This transport device 18 is in the 1 Machine arrangement shown as an example is designed as a third conveyor belt 18. The third conveyor belt 18 is also preferably designed as a revolving endless belt. The transport device 18 of the second dryer 17 in this example transfers the dried sheets to a suction belt table 19, from which the sheets are removed, for example. B. by means of a second oscillating gripper 21 and optionally a transfer drum 33 cooperating with the second oscillating gripper 21 to a second coating device 22. The second coating device 22 is z. B. designed as a painting device, this second coating device 22 containing a coating material, e.g. B. applies a varnish in particular to a printed image previously created in the non-impact printing device 13. The second coating device 22 in turn has, as a transport device for sheets to be transported, a z. B. designed as a printing cylinder transport cylinder 23, with this transport cylinder 23 z. B. a printing cylinder 24 interacts with an applicator roller 26 that is set or at least adjustable to this printing cylinder 24, preferably in the form of an anilox roller, with at least one doctor blade 27 or a chamber doctor blade system 27 extending in the axial direction of the applicator roller 26.

The sheets are then transported by the transport cylinder 23 of the second coating device 22, for example. B. transported to a display 29 by means of a second gripper system 28, in particular a second chain conveyor, the sheets processed in this machine arrangement described as an example being deposited by the second gripper system 28 in the display, preferably in a second stack 32. In an advantageous embodiment, a third dryer 31 which dries the sheets coated in the second coating device 22 is provided in the area of the second gripper system 28, this third dryer 31 z. B. is designed as a hot air dryer and / or as a dryer that dries by IR radiation or by UV radiation. The display 29 can also be designed as a multi-stack display having a plurality of second stacks 32. The ones in the 1 The machine arrangement shown as an example is designed as a digital printing machine for use in an industrial printing process, in particular for the production of printed products in mass production.

2 shows a side view of the suction belt table 19, as seen e.g. B. in a machine arrangement according to 1 is arranged. The transport direction T of the sheets is in the 2 directed from right to left. The suction belt table is supplied with 19 individual sheets sequentially from one in the 2 only partially shown transport device 18 with a transport speed of several thousand sheets per hour, e.g. B. fed by around 10,000 sheets per hour. In this case, in their transport direction T, adjacent individual sheets, ie individual sheets immediately following one another in the sequence, are each spaced apart from one another by a gap. This gap is significantly smaller than a length of the sheets extending in the transport direction T of the sheets and is only a few millimeters, e.g. B. about 20 mm. In the preferred embodiment here, the transport device 18 upstream of the suction belt table 19 in the transport direction T of the sheets belongs to a dryer 17, this dryer 17 according to the in the 1 The machine arrangement shown as an example is a second dryer 17, the sheets being transported by this transport device 18 lying down, in particular lying on a conveyor belt, in a translational manner, ie along a linear transport route. The suction belt table 19 initially takes over each individual sheet in a conveying plane defined by the transport device 18 upstream of this suction belt table 19 and conceptually extended in the transport direction T of the sheets, this conveying plane preferably being oriented horizontally. As the sheets continue to travel, conveyor level E19 ( 4 ) of the suction belt table 19 with respect to the horizontal conveying plane of the transport device 18 arranged upstream of this suction belt table 19 has a downward inclination with an acute angle in the range between 5 ° and 30 °, preferably in the range between 15 ° and 25 °. At the end of the transport path determined by the suction belt table 19, each sheet abuts with its front edge in the transport direction T on front marks 36 of the oscillating gripper 21 arranged downstream of the suction belt table 19, this oscillating gripper 21 in the 1 The machine arrangement shown as an example is a second swing gripper 21. From this swing gripper 21, each sheet is individually transferred to a transfer drum 33 which interacts with this swing gripper 21. The sheets are completely braked at the front marks and aligned correctly.

In its preferred embodiment, the suction belt table 19 has a shingling device for sheets to be transported. The undercutting device is located above the conveying level E19 of the suction belt table 19, preferably over the entire width of the sheets, i.e. H. box-shaped housing extending transversely to the transport direction T of the sheet, the so-called blow box 37, with several blowing nozzles being arranged one behind the other in the blow box 37 on the side facing the conveying plane E19 of the suction belt table 19 in the transport direction T of the sheet. In the preferred embodiment, at least two rows of several blowing nozzles arranged next to one another are arranged one behind the other in the transport direction T of the sheets and in each case transversely to the transport direction T of the sheets. A respective blowing direction of the blowing nozzles is directed essentially parallel to the conveying plane E19 of the suction belt table 19 against the transport direction T of the sheets. The respective blowing direction of the blowing nozzles is z. B. determined by at least one guide surface channeling the flow of the blowing air, each arranged and / or molded on the blowing nozzle in question. The respective guide surface is on the side of the blow box 37 facing the conveying plane E19 of the suction belt table 19, for example. B. designed as a ramp protruding from this blow box 37. A blown air flowing out of the respective blowing nozzles is preferably provided by adjustable pneumatic valves, for example. B. controlled in time and / or intensity, with the valves z. B. are or are controlled by a preferably digital control unit 71 which processes a program. The valves are z. B. switched by the control unit 71 in particular in a cycle, with a cycle duration and / or a cycle frequency preferably being set depending on the feed of the sheets fed to the suction belt table 19. Valves controlled in a cycle by a preferably digital control unit 71 are also referred to as cycle valves.

In the transport direction T of the sheet, a bulkhead 38 is arranged in front of the first blowing nozzle or the first row of blowing nozzles in an area between the conveying plane E19 of the suction belt table 19 and the side of the blow box 37 facing this conveying plane E19, the bulkhead 38 being the front edge of a subsequent sheet, ie a sheet which directly follows a sheet lifted by the blowing air from at least one of the blowing nozzles of the blowing box 37, against the suction effect caused by the blowing nozzles arranged in the blowing box 37. That of at least one of the blowing nozzles or rows of blowing nozzles of the blowing box 37 from the conveying level E19 of the suction belt table 19 channels the blowing air flowing out of the at least one blowing nozzle of the blowing box 37 and directs this blowing air over the surface of the bulkhead 38 facing the blowing box 37. The bulkhead 38 points at its end located in the blowing direction preferably a concave curvature, this curvature giving the blown air an outflow direction facing away from the conveying plane E19 of the suction belt table 19, ie directed away. Through the bulkhead 38, the front edge of a sheet, which directly follows a sheet lifted by the blowing air from at least one of the blowing nozzles, remains unaffected until the raised sheet is affected by its own movement progress or feed directed in the transport direction T with its rear end This sheet in its transport direction T exposes the first blowing nozzle or row of blowing nozzles reached. In order to prevent the front edge of the sheet that immediately follows a sheet lifted by the blowing air from at least one of the blowing nozzles from being lifted prematurely due to the effect of the blowing nozzle or row of blowing nozzles exposed from the rear end of the preceding sheet, the blowing air of the relevant one Blowing nozzle or row of blowing nozzles is switched off by means of the respective associated valve depending on the movement progress or advance of the sheet that is currently raised from the conveying level E19 of the suction belt table 19 and is directly preceding an arch located between the bulkhead 38 and the conveying level E19 of the suction belt table 19.

A sheet lifted by the blowing nozzles or rows of blowing nozzles is brought into a specific position, e.g. B. raised by a distance from the side of the blowing box 37 facing the conveying plane E19 of the suction belt table 19, this floating height depending on the intensity of the respective blown air and / or on the mass of the relevant sheet and / or on the transport speed of the relevant sheet is. To prevent sheets from e.g. B. large mass and / or high transport speed during their transport in the conveying level E19 of the suction belt table 19 begin to vibrate and flutter, is preferably in the area between the conveying level E19 of the suction belt table 19 and the side of the blow box 37 facing this conveying level E19 Support plate supporting the raised arch is provided, the z. B. at an acute angle to the side of the blow box 37 facing the conveying plane E19 of the suction belt table 19. Support plate z. B. is designed in the form of an air-permeable grid. The sheet raised by the suction of the blown air and placed against the support plate is guided there in a quiet movement, ie without fluttering, in its transport direction T along this support plate. In the conveying plane E19 of the suction belt table 19, at least in an area opposite the blow box 37, there are preferably several openings 39 ( 3 ) is provided, through which air flows under the currently raised sheet to equalize the pressure. These openings 39 are z. B. circular with a diameter in the range of a few millimeters. In addition, several suction chambers 41 whose respective fluidic effects can be controlled are arranged below the conveying level E19 of the suction belt table 19. These suction chambers 41 are preferably arranged one behind the other in the transport direction T of the sheets and z. B. can be switched in particular individually and independently of one another in their respective pressure by means of a suction device controlled by the control unit 71.

3 shows in a top view the one in the 2 shown suction belt table 19. The transport direction T of the sheets is as in the 2 directed from right to left. Individual sheets are fed sequentially to the suction belt table 19 by a transport device that transports the sheets translationally, in particular by a transport device belonging to a dryer 17. The sheets each lie on at least one conveyor belt 18, preferably on several, e.g. B. on two conveyor belts 18 arranged parallel to one another in the transport direction T of the sheets. These conveyor belts 18 are each z. B. as endlessly rotating flat belts or

Flat belt designed. At the transition from the transport device upstream of the suction belt table 19 to this suction belt table 19, a guide device 42 is arranged which extends transversely to the transport direction T of the sheets and preferably has a plurality of lifting nozzles 43 arranged in at least one row. In the transport direction T of the sheet there then follows at least one take-over belt 44, which z. B. is designed as a rotating flat belt arranged in the middle region of the conveying plane E19 of the suction belt table 19 and also preferably as a suction belt, the suction belt having a perforation at least in sections. In the transport direction T of the sheets, at least one bend 46 follows the transfer belt 44 or in its effective area in the conveying plane E19 of the suction belt table 19, preferably for a gradual curvature of the previously z. B. horizontal conveyor level several successive kinks 46; 47, with 46; 47 the conveying level E19 of the suction belt table 19 compared to the previous orientation of the The conveying plane may experience a further downward inclination with an acute angle in the range between 5° and 30°. In the in the 2 and 3 The example shown are two consecutive bends 46; 47 shown, the first bend 46 being arranged in the effective range of the transfer belt 44 and the second bend 47 at a short distance of less than one sheet length in the transport direction T of the sheet after the transfer belt 44. In the conveying level E19 of the suction belt table 19 there are z. B. the distance between the bends 46 symmetrically to its center line M; 47 preferably spanning two jump belts 48 z. which are arranged parallel to one another in the transport direction T of the sheets. B. arranged in the form of revolving endless belts, each preferably designed as a suction belt. The jump belts 48 are pivotally mounted at their rear end in the transport direction T of the sheets, which is thus reached first by a sheet brought in in particular by the transfer belt 44, so that these jump belts 48 open obliquely upwards in an acute angle opening in the transport direction T of the sheets can be pivoted out of the previous conveying level E19 of the suction belt table 19 and, in their exposed operating state, form a ramp for the sheets to be transported. In the 2 the jump belts 48 are shown in their normal operating state, ie not swung out, preferably flush with the remaining conveying level E19 of the suction belt table 19. In a preferred embodiment, a plurality of nozzles 49, each preferably designed as Venturi nozzles, are arranged at least in the respective longitudinal edge regions of the region of the conveying plane E19 of the suction belt table 19 spanned by the jump belts 48.

Above the conveying plane E19 of the suction belt table 19, a catch blower 51 extending transversely to the transport direction T of the sheets is arranged at a distance A51 ( 2 and 3 ), this catch blower 51 having a plurality of blowing nozzles which are arranged in a row extending over the entire width B19 of the conveying plane E19 of the suction belt table 19. Below the catch blower 51, in the conveying plane E19 of the suction belt table 19, a switching area 52, which extends in the transport direction T of the sheet and has several suction holes 53, begins in particular in its central area. The suction holes 53 in the switching area 52 form and open a fluidic connection to at least one of the preferably several Suction chambers 41 arranged below the conveying level E19 of the suction belt table 19, these suction chambers 41 being switched or at least switchable by the control unit 71 individually and independently of one another in their respective pressure, so that in this switching area 52 by means of the suction bores 53 and by the respective setting of the Pressure in the relevant suction chamber 41 in the conveying plane E19 of the suction belt table 19, a negative pressure is set or at least adjustable. The suction holes 53 arranged in the switching area 52 are z. B. symmetrically to the center line M of the conveying plane E19 of the suction belt table 19 in several, e.g. B. arranged in two rows and each z. B. designed as a sucker using the Bernoulli effect. In the transport direction T the sheet adjoins the switching area 52 z. B. in a manner that overlaps with the switching area 52, at least one feed belt 54, designed in particular as a suction belt, the suction belt having a perforation at least in sections, the at least one feed belt 54 preferably extending in the transport direction T of the sheets to below the blow box 37 of the undercutting device. The at least one feed belt 54 is preferably designed as a revolving endless belt. In a preferred embodiment, e.g. B. symmetrically to the center line M of the conveying level E19 of the suction belt table 19 several, e.g. B. two feed belts 54 are provided. The area that extends in the conveying plane E19 of the suction belt table 19 opposite the blow box 37 and in which preferably several openings 39 ( 3 ) are provided, through which air flows under a sheet currently raised by the shingling device to equalize the pressure, the sheet extends at the edge in the conveying plane E19 of the suction belt table 19 in the transport direction T at least partially along the at least one feed belt 54.

In the transport direction T the sheets follow the at least one feed belt 54 and / or after the undercutting device in the conveying level E19 of the suction belt table 19 z. B. arranged symmetrically to their center line M, preferably each designed as a revolving endless belt, brake belts 56, which have the function of controlling the respective transport speed of sheets brought in before they are transferred to a transport device immediately downstream of the suction belt table 19, e.g. B. to a swing gripper 21 to reduce. The sheets, which are preferably reduced in their respective transport speed, are then captured as they progress further in the transport direction T by a rotating or at least rotatable suction roller 57, which is subjected to negative pressure by a suction device, this suction roller 57 being transverse to the transport direction T of the sheets, preferably at least over the entire Width of the sheets or over the entire width B19 of the suction belt table 19 extends. Then each of the sheets comes one after the other and individually from the Suction roller 57 held with its front edge in the transport direction T, ie its front edge z. B. to the front marks 36 of the oscillating gripper 21 immediately downstream of the suction belt table 19. Through an interaction of the undercutting device, the brake bands 56, the suction roller 57 and the front marks 36 of the oscillating gripper 21, the sheets that were previously transported one behind the other lying individually, each with a gap between them transferred into a shingled stream before these sheets are sent to a transport device immediately downstream of the suction belt table 19, e.g. B. to a swing gripper 21, to then be transferred to a suction belt table 19 having this z. B. machine arrangement designed as a digital printing machine rotates to a coating device 22, e.g. B. to be transported to a coating device 22 designed as a painting device and through it.

When operating such a machine arrangement, especially in the industrial printing process of a digital printing machine, there can always be a malfunction in a system downstream of the suction belt table 19 for various reasons, e.g. B. come as a coating device 22 trained processing station. A serious malfunction in such a processing station results in the transfer of sheets to the transport device downstream of the suction belt table 19 having to be abruptly interrupted. This operating case forms a stopper. With a stopper, sheets in transport in the machine arrangement must be collected and stacked very quickly and effectively. In a machine arrangement forming a digital printing machine, however, due to the structural conditions, in particular due to a lack of required space in height, it is not possible to work in a processing station upstream of the suction belt table 19, such as. B. in a first coating device 05 or in the non-impact printing device 13 or in a dryer 17 downstream of the non-impact printing device 13, a large number of in rapid succession, i.e. H. to collect and stack sheets that are transported close together at high transport speeds. It is not a satisfactory solution to arrange an ejection device in the transport direction T of the sheets after the dryer 17 downstream of the non-impact printing device 13 and in front of the suction belt table 19, with this ejection device all still coming from the non-impact printing device 13 in the case of a stopper The downstream dryer 17 directs the sheet led out under the suction belt table 19 and deposits it there. Because the sheets can only be stored there in a more or less orderly manner. This solution also has the disadvantage that sheets collected under the suction belt table 19 can only be removed again under very ergonomically unfavorable conditions. In addition, there is hardly any possibility of arranging the conveying elements required in the area of the discharge device for the transfer of the flow of individual sheets from the dryer 17 in trouble-free operation. Without such suitable conveying elements, however, there can be a loss of the holding force with which the sheets, which are usually significantly warped due to the heat input during drying, are held. The result would be a disruption in the transport of the sheets. The task therefore arises of catching and stacking the sheets on the suction belt table 19 before they are transferred to the transport device downstream of the suction belt table 19. However, it should be noted here that it is not possible to carry out continuous undercutting to form stacks on the undercutting device of the suction belt table 19. This is because the nozzles that suck from above onto the rear edge of the sheet in question are ineffective for an immediately following sheet at the latest, because the previous sheet is not transported away when the sheets are collected and thus shields the suction effect on the next sheet underneath.

A suction belt table 19 with a catching device 58 is therefore proposed, with which catching device 58 successive individual sheets are caught and stacked on the suction belt table 19 before being transferred to a transport device downstream of the suction belt table 19. In the preferred embodiment, this suction belt table 19, which preferably has a shingling device, is arranged in the transport direction T of the sheets after a dryer 17 downstream of a non-impact printing device 13. In a particularly preferred embodiment, the suction belt table 19 is arranged in a machine arrangement at a point at which the sheets are transferred from a linear transport path immediately upstream of this suction belt table 19 to a curved, in particular circular-arc-shaped, transport path immediately downstream of this suction belt table 19.

The proposed catching device 58 has a slider crank mechanism, the coupling of which has at least one stop surface 66 for the sheets to be caught. Details of the safety device 58 and its functionality are described below using the 4 until 6 described.

4 shows an example of a side view of the catching device 58. This catching device 58 is inactive as long as it is inactive, ie for example from the control unit unit 71 is unactuated, arranged below the conveying plane E19 of the suction belt table 19, preferably approximately a sheet length extending in the transport direction T of the sheets from a line drawn by the catch blower 51 perpendicular to the conveying plane E19 of the suction belt table 19 corresponding to the distance A51 away at the end of the switching area 52 of this suction belt table 19, which has suction holes 53. The catching device 58 has a drive 59, which is preferably designed as a double-acting pneumatic cylinder 81, the cylinder piston 82 of which can be acted upon by compressed air on both sides ( 8th ). A bidirectionally linearly movable piston rod 61 of the pneumatic cylinder 81 is connected to a crank 62 designed as an angle lever to form an articulation point G61, the crank 62 being rotatably mounted in a pivot point D62 which is stationary in the suction belt table 19. The crank 62 designed as an angle lever has a short lever and a lever which is longer than this short lever, the short lever connecting the pivot point G61, at which the piston rod 61 of the pneumatic cylinder 81 is connected to the crank 62, to the pivot point D62 of the Crank 62 connects. The crank 62 is in turn connected to a coupling 63 to form a hinge point G62. The longer lever of the crank 62 extends between its pivot point D62 and the articulation point G62, at which the crank 62 is connected to the coupling 63. The coupling 63 and the crank 62 driving the coupling 63 form a sliding crank mechanism in their interaction, with an end point E2 of the coupling 63 facing away from the drive 59 of the catching device 58 being bidirectionally linearly movable along a path 64 arranged parallel to the conveying plane E19 of the suction belt table 19. The end point E2 of the coupling 63 facing away from the drive 59 of the catching device 58 and the pivot point D62 of the crank 62 therefore lie on a straight line G64 connecting them, this straight line G64 running parallel to the conveying plane E19 of the suction belt table 19.

The coupling 63 has at least one stop surface 66 for sheets to be caught in an area between its end point E1 facing the drive 59 of the catching device 58 and the articulation point G62, at which the crank 62 is connected to the coupling 63. The relevant stop surface 66 is therefore preferably a component of the coupling 63. The relevant stop surface 66 is preferably made of a plastic, e.g. B. made of a polyamide (abbreviation PA) or a thermoplastic such as. B. polyoxymethylene (abbreviation POM).

In a preferred embodiment, the slider crank mechanism has a central slider crank, which means that the three in the 4 shown routes G62-D62, G62-E2 and G62-E1 are each of the same length and the end points E1; E2 of the coupling 63 together with the articulation point G62 arranged in between, all on one of the end points E1; E2 of the paddock 63 connecting straight lines G63 lie. The length ratio of the short lever and the longer lever of the crank 62 to one another is such that they translate a movement triggered by the drive 59 of the safety catch 58 and acting on the paddock 63 into a faster one. The gear ratio i to the faster is preferably at least 1:5 (i = 0.2).

In connection with the 5 until 7 the functionality of the catching device 58 can be seen. The 2 and 5 show the catching device 58 in its inactive, ie unactuated, starting position or parking position, in which the at least one stop surface 66 formed on the coupling 63 is arranged below the conveying plane E19 of the suction belt table 19. This means that the sheets can pass through the suction belt table 19 in its conveying plane E19 unhindered, which is what happens in the 5 is indicated by two consecutive directional arrows. Like from the 5 As can be seen, the piston rod 61 of the pneumatic cylinder 81 forming the drive 59 of the catching device 58 is extended by a corresponding application of compressed air to this pneumatic cylinder 81 and the end point E2 of the coupling 63 facing away from the drive 59 of the catching device 58 takes its position from the drive 59 on the path 64 the most distant position of the catching device 58.

The 6 and 7 show the catching device 58 in its catching position. In the catching position, the at least one stop surface 66, which is preferably formed on the paddock 63, pierces through a corresponding, e.g. B. slot-shaped opening 67 ( 3 ) the conveying plane E19 of the suction belt table 19 and is positioned preferably perpendicular to this conveying plane E19 by a pivoting movement from a position previously inclined at a preferably acute angle to the conveying plane E19 of the suction belt table 19 ( 6 and 7 ), so that sheets transported on the suction belt table 19 are against the at least one set up, e.g. B. each protruding stop surface 66 about 50 mm from the conveying plane E19 of the suction belt table 19 (see directional arrows in the 6 ) and in this way are caught and prevented from further movement progress in the transport direction T. Sheets that are transported one after the other and each abut against the set-up stop surface 66 are placed on top of each other in the transport direction T of these sheets in front of the set-up stop surface 66 and are thus stacked. The col is in the catching position Ben rod 61 of the pneumatic cylinder 81 forming the drive 59 of the catching device 58 is retracted by applying compressed air to this pneumatic cylinder 81 and the end point E2 of the paddock 63 facing away from the drive 59 of the catching device 58 takes its next position on the path 64 to the drive 59 of the catching device 58 a.

7 shows an excerpt from the 2 with jump belts 48, which are shown in their operating state, which is exposed obliquely upwards from the previous conveying level E19 of the suction belt table 19 in an acute angle opening in the transport direction T of the sheets, and with a z. B. activated by the control unit 71 catch blower 51, its activation in the 7 is indicated by a blowing direction arrow directed towards the conveying plane E19 of the suction belt table 19.

If the operating case that forms a stopper occurs, in one of the suction belt table 19 downstream, e.g. B. designed as a coating device 22 processing station of the machine arrangement having the suction belt table 19 a serious malfunction occurs with the result that the transfer of sheets to the transport device downstream of the suction belt table 19 has to be abruptly interrupted, then the catching device 58 is switched to its catching position by the Drive 59 of the catching device 58 is actuated automatically, in particular program-controlled, by a control unit 71, usually by the further control unit 71, which preferably controls all functions of the suction belt table 19. This control unit 71 controls z. B. also the valves of the blow box 37 ( 2 ). At the same time as the safety catch 58 is actuated, z. B. the transport speed of the sheets can be reduced by the transport devices upstream of the catching device 58 in the transport direction T of the sheets reducing their respective transport speed. Even if the transport speed of a transport device upstream of the catching device 58 in the transport direction T of the sheets is not immediately reduced when the catching device 58 is actuated, e.g. B. the transport speed of the ski jump belts 48 and / or the feed belt 54, the negative pressure set in the relevant suction chamber 41 is switched off in each case by means of a suction device 72 controlled by the control unit 71, this suction chamber 41 being switched off by means of the vacuum in the conveying plane E19 of the suction belt table 19 formed suction bores 53 is fluidly connected to the relevant switching area 52 and at least partially overlaps with a floor plan of the stack of sheets to be caught to be formed. The at least one stop surface 66 of the catching device 58 is then shot into a sheet gap between the rear edge of a previous sheet and a front edge of a first subsequent sheet to be caught. For this purpose, the control unit 71 actuates at least one pneumatic switching valve 86, preferably two pneumatic switching valves 86 at the same time; 87, so that the piston rod 61 of the pneumatic cylinder 81 forming the drive 59 of the safety catch 58 is retracted.

In an advantageous embodiment, this pneumatic cylinder 81 has a base chamber 68 and a bearing chamber 69 which is separated from the base chamber 68 by a cylinder piston 82 which is firmly connected to the piston rod 61, with a first pneumatic switching valve 86 being connected to the base chamber 68 and a second pneumatic switching valve 87 being connected to the Storage chamber 69 is connected. These two switching valves 86; 87 are each controlled by the control unit 71 of the safety gear 58. In a first embodiment variant, the bottom chamber 68 can have barometric pressure. In another second embodiment variant, the bottom chamber 68 can have a differential pressure greater than the barometric pressure and less than the pressure in the storage chamber 69. In a preferred embodiment, the piston rod 61 of the pneumatic cylinder 81 forming the drive 59 of the catching device 58 is z. B. retracted at 7 bar. When the piston rod 61 of the pneumatic cylinder 81 is retracted, the cylinder piston 82 of the pneumatic cylinder works against in the bottom chamber 68 z. B. compressed air pre-stressed at 2 bar, which can escape in a throttled manner via the open pneumatic switching valve 86 of the bottom chamber 68 and, if necessary, via an adjoining throttle valve 91. The braking effect of this counterpressure only sets in relatively late, so that the movement of the cylinder piston 82 and thus also the piston rod 61 initially experiences a very large acceleration with the resulting speed before the movement of the cylinder piston 82 is braked at its end by the actively clamped air column and the residual speed at an end position damping element 83; 84 of the pneumatic cylinder 81 is braked. This very rapid movement of the cylinder piston 82 is strongly translated by the crank 62 onto the coupling 63 arranged in a central thrust crank position, preferably with a transmission ratio i to the faster of at least 1:5 (i = 0.2).

With the proposed slider crank mechanism, it is possible to have at least one stop surface 66 of the catching device 58 even at a high transport speed of the sheets of several thousand sheets per hour, e.g. B. of about 10,000 sheets per hour through a z. B. only about 20 mm measuring arch gap through into the to bring the catching position. The response time that can be achieved with the proposed push-crank mechanism significantly exceeds the switching times of simple folding and/or sliding mechanisms, e.g. B. are driven by switching magnets or directly, ie gearlessly by a pneumatic cylinder 81. Another advantage of the solution found is that the proposed slider crank mechanism is comparatively simple and space-saving.

This results in a machine arrangement with several processing stations each processing sheets, these processing stations being arranged one behind the other in the transport direction T of the sheets, with at least one of these processing stations having a transport device 18 which transports the sheets horizontally along a linear transport route, this transport device 18 immediately in a sequence successive individual sheets are each designed to be transported at a distance from each other by a gap, with this transport device 18, which transports the sheets lying along a linear transport route, being followed by a suction belt table 19, the suction belt table 19 having a catching device 58 with a catching position assumed as a result of an actuation in a sequence has successive individual sheets, the catching device 58 being in its catching position by the transport device 18, which transports the sheets horizontally along a linear transport route and is arranged upstream of the suction belt table 19, sheets fed to the suction belt table 19 before each transfer to a transport device downstream of the suction belt table 19 catches and stacks on the suction belt table 19. A control unit 71 provided for the suction belt table 19 actuates the catching device 58 depending on a fault that has occurred in a processing station downstream of the suction belt table 19 in such a way that the catching device 58 assumes its catching position. In the preferred embodiment, the transport device 18 arranged upstream of the suction belt table 19, which transports the sheets horizontally along a linear transport path, belongs to a dryer 17. This dryer 17 is z. B. downstream of a processing station designed as a non-impact printing device 13. The suction belt table 19 is also preferably arranged upstream of a processing station designed as a coating device 22, in particular a processing station designed as a painting device. In this case, the coating device 22 has, as a transport device for sheets to be transported, in particular a transport cylinder 23, with this transport cylinder 23 preferably a printing cylinder 24 interacting with an application roller 26 that is set or at least adjustable to this printing cylinder 24, with at least one doctor blade in the axial direction of the application roller 26 27 or a chamber doctor system 27 extends. This machine arrangement is designed to transport the sheets at a transport speed of preferably several thousand sheets per hour, in particular approximately 10,000 sheets per hour. The transport device 18 located upstream of the suction belt table 19, which transports the sheets horizontally along a linear transport path, is designed to transport the individual sheets that follow one another in a sequence, each with a sheet gap that preferably measures approximately 20 mm.

The result is a suction belt table 19 for sheet-shaped substrates to be transported individually, the suction belt table 19 being arranged between a transport device arranged upstream in the transport direction T of the substrates and a corresponding downstream transport device, the suction belt table 19 having a catching device 58 with a catching position assumed as a result of its actuation for individual substrates following one another in a sequence, the catching device 58 in its catching position catching the substrates supplied to the suction belt table 19 by the upstream transport device on the suction belt table 19 before their respective transfer to the transport device downstream of the suction belt table 19, ie on one directed in the transport direction T Movement progress hinders and preferably stacks. The transport device arranged upstream of the suction belt table 19 has a translational transport route for the sheet-shaped substrates to be transported individually and/or the transport device arranged downstream of the suction belt table 19 has a rotary transport route or a translational transport route for the sheet-shaped substrates to be transported. A particularly digital control unit 71 is provided, this control unit 71 actuating the catching device 58 depending on a fault that has occurred along the transport route belonging to the transport device downstream of the suction belt table 19 in such a way that the catching device 58 assumes its catching position. The catching device 58 has at least one pivotable stop surface 66 for substrates to be caught, the relevant stop surface 66 being arranged below a conveying plane E19 of the suction belt table 19 in the state of the catching device 58 that is not actuated by the control unit 71 and in the state of the catching device 58 that is actuated by the control unit 71 through an opening 67 in the conveying plane E19 of the suction belt table 19 is positioned perpendicular to this conveying plane E19, so that substrates transported on the suction belt table 19 come out against the at least one set up, from the conveying plane E19 of the suction belt table 19 locating stop surface 66. In its preferred embodiment, the catching device 58 has a slide-crank mechanism, the slide-crank mechanism having a coupling 63 and a crank 62 which interacts with the coupling 63, the crank 62 being driven by a drive 59. The crank 62 is rotatably mounted in a pivot point D62 which is stationary in the suction belt table 19, the crank 62 being designed as an angle lever and having a short lever and a lever which is longer in comparison to this short lever, the short lever having a pivot point G61 which the drive 59 engages on the crank 62, connects to the pivot point D62 of the crank 62, the longer lever of the crank 62 extending between its pivot point D62 and an articulation point G62 at which the crank 62 is connected to the coupling 63. The length ratio of the short lever and the longer lever of the crank 62 to one another is such that they translate a movement acting from the drive 59 of the catching device 58 onto the paddock 63 into a faster one. The gear ratio i to the faster is preferably at least 1:5. An end point E2 of the paddock 63 facing away from the drive 59 of the catching device 58 is bidirectionally linearly movable along a path 64 arranged parallel to the conveying plane E19 of the suction belt table 19, the end point E2 of the paddock 63 facing away from the drive 59 of the catching device 58 and the pivot point D62 of the crank 62 are arranged on a straight line G64 connecting these two points, this straight line G64 running parallel to the conveying plane E19 of the suction belt table 19. The at least one stop surface 66 for substrates to be caught is formed in an area between an end point E1 of the coupling 63 facing the drive 59 of the catching device 58 and the articulation point G62 at which the crank 62 is connected to the coupling 63. The slider crank mechanism preferably has a central slider crank, in which the three sections G62-D62; G62-E2; G62-E1 are each of the same length and the end points E1; E2 of the coupling 63 together with the articulation point G62 arranged in between, all on one of the end points E1; E2 of the coupling 63 connecting straight lines G63 are arranged. The drive 59 of the catching device 58 is advantageously designed as a double-acting pneumatic cylinder 81, this pneumatic cylinder 81 having a base chamber 68 and a bearing chamber 69 which is separated from the base chamber 68 by a cylinder piston 82 which is firmly connected to its piston rod 61. The bearing chamber 69 is arranged at the end of the pneumatic cylinder 81 that faces the articulation point G61 at which the drive 59 engages the crank 62. The bottom chamber 68 is arranged at the end of the pneumatic cylinder 81 that faces away from the articulation point G61 at which the drive 59 engages the crank 62. A first pneumatic switching valve 86 is connected to the bottom chamber 68 and a second pneumatic switching valve 87 is connected to the bearing chamber 69, these two switching valves 86; 87 are each controlled by the control unit 71 of the safety gear 58. The bottom chamber 68 either has barometric pressure or the bottom chamber 68 has a differential pressure greater than the barometric pressure and less than the pressure in the storage chamber 69. The piston rod 61 of the pneumatic cylinder 81 is pressurized by the bearing chamber 69 z. B. retracted at 7 bar. The cylinder piston 82 of the pneumatic cylinder 81 works against in the bottom chamber 68 when the piston rod 61 of the pneumatic cylinder 81 is retracted. B. compressed air preloaded with 2 bar, this compressed air being provided from a compressed air source 93 connected to the bottom chamber 68.

This also results in a suction belt table 19 for the lying transport of individual sheet-shaped substrates in a conveying level E19, the suction belt table 19 having a catching device 58 and at least one skid belt 48, the catching device 58 and the at least one skid belt 48 each being controlled by a control unit 71 of two different operating states, with respect to the catching device 58 and the at least one ski jump band 48, the first operating state is an inactive operating state and the second operating state is an activated operating state, the catching device 58 being at least one vertical in its activated state to the conveying plane E19 of the suction belt table 19 has stop surface 66 for substrates to be caught, the at least one jump belt 48 in the transport direction T of the substrates by at least a substrate length extending in the transport direction T of the substrates in front of the at least one stop surface set up perpendicular to the conveying plane E19 of the suction belt table 19 66 is arranged, wherein the at least one jump belt 48 in its activated state with its end directed in the transport direction T of the substrates is pivoted obliquely upwards out of the conveying plane E19 of the suction belt table 19 at an acute angle opening in the transport direction T of the substrates. The suction belt table 19 is arranged between a transport device arranged upstream in the transport direction T of the substrates and a corresponding downstream transport device, the transport device arranged upstream of the suction belt table 19 having a translational transport route for the sheet-shaped substrates to be transported individually and/or the transport device arranged downstream of the suction belt table 19 rotary transport route or a translator cal transport route for the sheet-shaped substrates to be transported. Advantageously, in a region extending in the transport direction T of the substrates between the erected stop surface 66 of the catching device 58 and the at least one skid belt 48, which is pivoted obliquely upwards at an acute angle out of the conveying plane E19 of the suction belt table 19, above the conveying plane E19 of the suction belt table 19 a catch blower 51 with a plurality of blowing nozzles arranged in a row extending transversely to the transport direction T of the substrates, the catch blower 51 in its activated state blowing air from its blowing nozzles z. B. blows vertically in the direction of the conveying level E19 of the suction belt table 19. The control unit 71 actuates the catching device 58 depending on a fault that has occurred along the transport route belonging to the transport device downstream of the suction belt table 19 in such a way that the catching device 58 sets up its at least one stop surface 66 for substrates to be caught perpendicular to the conveying plane E19 of the suction belt table 19 and / or This control unit 71 actuates the at least one skid belt 48 depending on the disturbance that has occurred along the transport route belonging to the transport device downstream of the suction belt table 19 in such a way that the at least one skid belt 48 is pivoted obliquely upwards out of the conveying plane E19 of the suction belt table 19 at the acute angle and/or this control unit 71 actuates the catch blower 51 depending on the disturbance that has occurred along the transport route belonging to the transport device downstream of the suction belt table 19 in such a way that the catch blower 51 blows air from its blowing nozzles in the direction of the conveying plane E19 of the suction belt table 19. The suction belt table 19 is preferably designed in such a way that in the transport direction T of the substrates after the catching device 58, a blow box 37 of an undercutting device belonging to the suction belt table 19 is arranged above the conveying plane E19 of the suction belt table 19. In addition, in the transport direction T of the substrates in front of the at least one skid belt 48 at the transition from the transport device upstream of the suction belt table 19 to this suction belt table 19 z. B. a guide device 42 extending transversely to the transport direction T of the substrates with several lifting nozzles 43 is arranged. Also, in the area extending in the transport direction T of the substrates between the set up at least one stop surface 66 of the catching device 58 and the at least one skid belt 48 which is pivoted obliquely upwards at the acute angle out of the conveying plane E19 of the suction belt table 19, there is an area below the conveying plane E19 of the suction belt table 19 e.g. B. at least one suction chamber 41 is arranged, the respective suction chamber 41 being set or at least adjustable in its respective pressure by the control unit 71, from the control unit 71 through suction bores 53 formed in the conveying plane E19 of the suction belt table 19 to the relevant suction chamber 41 in the conveying plane E19 of the suction belt table 19 a negative pressure is set or at least adjustable. The negative pressure set in the conveying plane E19 of the suction belt table 19 by means of the suction chamber 41 is switched off in the event of a fault occurring along the transport route belonging to the transport device downstream of the suction belt table 19. The control unit 71 is preferably designed in such a way that it reduces a transport speed of the substrates at least in the transport device upstream of the catching device 58 in the transport direction T of the substrates. Preferably, in the transport direction T of the sheet, two skid belts 48 arranged parallel to one another are provided in the form of revolving endless belts, these two skid belts 48 being arranged symmetrically to the center line M of the conveying plane E19 of the suction belt table 19.

In the following it is assumed that a pneumatic drive 59 controlled by the control unit 71 actuates the safety catch 58. As already shown, when a stopper is in operation, due to the high transport speed of several thousand sheets per hour transported in the conveyor level E19 of the suction belt table 19, e.g. B. of around 10,000 sheets per hour, and the relatively small gap of z. B. only about 20 mm between individual sheets immediately following one another in their transport direction T is required to set up the at least one stop surface 66 of the catching device 58 in the conveying plane E19 of the suction belt table 19 in a very short time and thus to shoot into the linear transport path of the sheets, so that a transfer of further sheets fed to the suction belt table 19 after setting up the at least one stop surface 66 of the catching device 58 to a curved, in particular circular-arc-shaped transport path of a transport device downstream of the suction belt table 19 is effectively prevented. With these short switching times, a cylinder piston 82 in a pneumatic cylinder 81 exerts such a large force impulse on the internal stops of this pneumatic cylinder 81 as a result of the kinetic energy achieved that these stops are worn out in a very short time and are therefore destroyed. In this respect, there is a need for a solution for improved damping on the inner stops of the pneumatic cylinder 81, so that this pneumatic cylinder 81 has sufficient wear resistance and thus the longest possible operating life when used as described.

Like from the 8th As can be seen, it is therefore proposed that a pneumatic circuit is provided for the operation of the double-acting pneumatic cylinder 81 of the catching device 58, which controls the movement of the cylinder piston 82 in such a way that a positive acceleration and in a negative acceleration is set for a second half of its stroke following the first half. This pneumatic cylinder 81 has a base chamber 68 and a bearing chamber 69 separated from the base chamber 68 by the cylinder piston 82, the cylinder piston 82 being firmly connected to the piston rod 61. The bearing chamber 69 is arranged at the end of the pneumatic cylinder 81 that faces the articulation point G61 at which the drive 59 engages the crank 62. The bottom chamber 68 is arranged at the end of the pneumatic cylinder 81 that faces away from the articulation point G61 at which the drive 59 engages the crank 62. The cylinder piston 82 preferably has an end position damping element 83 on both sides; 84 on. The pneumatic circuit described in detail below is realized by changing a dynamic pressure balance in the two chambers 68; 69 of the pneumatic cylinder 81 has a controlled acceleration phase and a controlled braking phase over the entire stroke of the cylinder piston 82.

The pneumatic circuit has a first pneumatic switching valve 86 and a second pneumatic switching valve 87, both switching valves 86; 87 are each preferably electrically actuated by the control unit 71. Both switching valves 86; 87 are each connected to their respective compressed air source 93 in one of their switching positions. 8th shows the operating position of the pneumatic cylinder 81 in which the piston rod 61 of the pneumatic cylinder 81 forming the drive 59 of the catching device 58 is retracted and thus the catching device 58 is activated, which means that the stop surface 66 of the catching device 58 is set up in the conveying plane E19 of the suction belt table 19 . At least the switching valve 86 for the bottom chamber 68 is preferably preceded by a pressure reducer 88 in order to build up a defined initial counterpressure in the bottom chamber 68 when the compressed air flows out. But a pressure reducer 89 can also be connected upstream of the switching valve 87 for the storage chamber 69. In addition, a throttle valve 91 is arranged downstream of the switching valve 86 of the bottom chamber 68 in order to use this throttle valve 91, whose cross section is preferably adjustable, to influence the outflow speed of the compressed air from the bottom chamber 68 and thus the dynamic pressure curve in the pneumatic cylinder 81 and thus the speed of the cylinder piston 82. It can e.g. B. it can also be provided that a throttle valve 92 is arranged in the air outlet from the bearing chamber 69 of the pneumatic cylinder 81 in order to limit the speed of the cylinder piston 82. The throttle valve 91 of the bottom chamber 68 and possibly the throttle valve 92 of the bearing chamber 69 are only activated when compressed air flows out of the respective chamber 68; 69 used in the atmosphere.

Before the catching device 58 is activated, the bearing chamber 69 of the pneumatic cylinder 81 is preferably depressurized, ie there is a pressure in it z. B. equal to barometric pressure. In an alternative embodiment, however, it can also be provided that the bearing chamber 69 of the pneumatic cylinder 81 is subjected to a pressure greater than barometric pressure via the pressure reducer 89 which may be connected to it, e.g. B. with a pressure that corresponds to the pressure in the bottom chamber 68, so preferably with a pressure z. B. from 2 bar. If in both chambers 68; 69 set pressure is the same, the cylinder piston 82 is held in a stable end position. In which with compressed air e.g. B. from a base chamber 68 preloaded at 2 bar, an air mass that can be controlled via the pressure is provided and is required to brake the travel movement of the cylinder piston 82 that occurs when the safety catch 58 is activated. The activation of the catching device 58 with the shooting of its at least one stop surface 66 into a sheet gap between the rear edge of a previous sheet and the front edge of a first subsequent sheet to be caught occurs in that the two switching valves 86; 87 can be actuated by the control unit 71 in particular at the same time. As a result, the storage chamber 69 is supplied with compressed air from its compressed air source 93 at more than 5 bar, in particular at a pressure of z. B. filled to 7 bar and the air in the base chamber 68, which is preloaded with approx is pending, which sets this cylinder piston 82 in motion. Controllable via the air mass trapped in the bearing chamber 69 and the opening cross section of the throttle valve 91, the braking effect sets in such that the movement of the cylinder piston 82 initially experiences a very large acceleration with the resulting speed before this movement of the cylinder piston 82 is largely controlled at the end actively clamped air column is braked and only a remaining residual speed of less than z. B. 10% of the previously achieved maximum possible speed is braked on the end position damping element 83 of the pneumatic cylinder 81. When the safety catch 58 is activated, the cylinder piston 82 is accelerated over the first half of its stroke and over his second half slowed down. In the first half of its stroke, the cylinder piston 82 reaches its maximum possible speed. In the theoretically ideal case, the cylinder piston 82 arrives in its respective end position at zero speed. However, this is not achieved in real operation. Therefore, the small residual energy still present at the respective end position damping element 83; 84 will be dismantled. This very rapid movement of the cylinder piston 82 is transmitted in a highly translated manner by the crank 62 to the coupling 63, which is preferably arranged in a central thrust crank position.

Through the pneumatic circuit described and with the setting values for the pressure mentioned as an example, it is possible to bring the at least one stop surface 66 of the catching device 58 into a catching position even at the already mentioned high transport speed of the sheets through the already mentioned very narrow sheet gap. The solution shown advantageously avoids high shock loads and load peaks in the entire kinematic system. This is because the clamped air column, which at the end dampens the drive movement of the cylinder piston 82, particularly in the base chamber 68, effectively prevents the cylinder base from being destroyed. In addition, a safe end position of the cylinder piston 82 is achieved in its retracted state without additional mechanical elements and therefore without additional costs. The pressure reduction in the storage chamber 69 also results in energy savings and a reduction in any possible leakage.

The 9 until 12 illustrate again, by way of example, in a diagram over the time t plotted on the abscissa, the dynamic behavior of some physical variables with respect to the cylinder piston 82 of the pneumatic cylinder 81 during a switching process, when the catching device 58 of the relevant suction belt table 19 is actuated in particular by a control signal from the control unit 71 is moved from its starting position to its catching position. 9 shows a change in position of the cylinder piston 82 between its two end positions in the pneumatic cylinder 81. An adjustment path z and thus the stroke of the cylinder piston 82 is here z. B. shown as 10 mm. 10 shows an example of the speed v of the cylinder piston 82 during its movement along the travel path z. 11 shows an example of the associated acceleration a with which the cylinder piston 82 carries out its movement along the adjustment path z. In the 12 The piston force F exerted by the cylinder piston 82 is then shown as an example.

As described, there is a suction belt table 19 for the lying transport of individual arcuate substrates in a conveying plane E19, the suction belt table 19 having a catching device 58 with at least one stop surface 66 for substrates to be caught, which is set up in its catching position in the conveying plane E19 of the suction belt table 19, with this at least a stop surface 66, starting from an inactive starting position of the catching device 58, is set up by a double-acting pneumatic cylinder 81 by a movement of its cylinder piston 82 into the catching position, this pneumatic cylinder 81 having a bottom chamber 68 and a bearing chamber 69 separated from the bottom chamber 68 by the cylinder piston 82 has, a pneumatic circuit being provided to control the movement of the cylinder piston 82, the pneumatic circuit having a first pneumatic switching valve 86 connected to the bottom chamber 68 and a second pneumatic switching valve 87 connected to the bearing chamber 69, both switching valves 86; 87 are each preferably electrically actuated by the control unit 71. The catching device 58 has a push-crank mechanism driven by the cylinder piston 82 of the pneumatic cylinder 81 according to the previous description. The movement of the cylinder piston 82 is controlled by the control unit 71 in such a way that a positive acceleration is set for the cylinder piston 82 in a first half of its stroke and a negative acceleration in a second half of its stroke following the first half. At least the first switching valve 86 connected to the bottom chamber 68 is preceded by a pressure reducer 88. At least the first switching valve 86 connected to the bottom chamber 68 is also z. B. a throttle valve 91, which is preferably adjustable in its opening cross section, is arranged downstream. The opening cross section of the throttle valve 91 is z. B. adjusted by the control unit 71 in such a way that the movement of the cylinder piston 82 at the end of the second half of its stroke has a residual speed of less than 10% of the maximum speed previously achieved in the first half of its stroke. The cylinder piston 82 preferably has an end position damping element 83 on both sides; 84, whereby the residual speed of the cylinder piston 82 remaining at the end of the second half of its stroke on the relevant end position damping element 83; 84 is braked. In the inactive starting position of the catching device 58, at least the bottom chamber 68 of the pneumatic cylinder 81 is at a pressure greater than barometric pressure, preferably at a pressure of z. B. 2 bar applied. To adjust the catching position of the catching device 58, the control unit 71 switches the first switching valve 86 connected to the bottom chamber 68 into one that drains the air mass from the bottom chamber 68 Position and at the same time the second switching valve 87 connected to the bearing chamber 69, so that the bearing chamber 69 is pressurized with compressed air at a pressure of more than 5 bar.

In connection with the 2 It has been described that the suction belt table 19 has in its conveying plane E19 a switching area 52 which extends in the transport direction T of the sheets and has a plurality of suction bores 53, with several suction chambers 41 whose respective fluidic effect can be controlled preferably being arranged below the conveying plane E19 of the suction belt table 19. These suction chambers 41 are preferably arranged one behind the other in the transport direction T of the sheets and in particular are switched or at least switchable individually and independently of one another in their respective pressure. It was also explained that the suction bores 53 in the switching area 52 form a fluidic connection to at least one of the preferably several suction chambers 41 arranged below the conveying level E19 of the suction belt table 19, in this switching area 52 by the respective adjustment of the pressure in the relevant suction chamber 41 by means of a suction device 72 controlled by the control unit 71 is set or at least adjustable at the suction bores 53 in the conveying plane E19 of the suction belt table 19. This negative pressure causes a sheet resting on the at least one feed belt 54 in the conveying plane E19 of the suction belt table 19 to be held in a frictional or non-positive manner. Because the switching area 52 overlaps at least partially with the floor plan of the sheet to be caught. The feed belt 54 in question is z. B. is designed as an endlessly rotating suction belt, with a suction belt having a perforation at least in sections, so that the negative pressure set at the suction holes 53 in the conveying plane E19 of the suction belt table 19 can be effective through the relevant feed belt 54 on the sheet lying on it. The feed belt 54 is preferably designed as a flat belt or as a flat belt.

If the operational situation of a stopper occurs and the at least one stop surface 66 of the catching device 58 is moved into its catching position, the frictional or non-positive connection between the respective feed belt 54 and the resting sheet must be canceled in a very short time, because otherwise the sheet on the relevant one Sheets resting on the feed belt 54 are pushed together when they impact on the at least one stop surface 66 of the catching device 58 protruding from the conveying plane E19 of the suction belt table 19, i.e. H. would be crumpled. Because at a transport speed of several thousand sheets per hour, e.g. B. of approximately 10,000 sheets per hour, it is neither possible, in the required short time, in the suction chamber 41 in question, the negative pressure set there by means of the suction device 72 controlled by the control unit 71 and thus the negative pressure acting on the sheet resting on the respective feed belt 54 To cancel the holding force or to stop the feed belt 54 in question as such in good time before the sheet in question hits the at least one stop surface 66 of the catching device 58. In order to avoid damage to an arch that is resting on the respective feed belt 54 when the stopper starts operating and is the first to strike against the at least one stop surface 66 of the catching device 58 protruding from the conveying plane E19 of the suction belt table 19, there is a need for the aforementioned frictional connection or force connection compared to switching off the suction device 72 of the relevant suction chamber 41 and/or compared to stopping the relevant feed belt 54.

Like from the 13 As can be seen, it is therefore proposed that at least one pneumatic clock valve 74 controlled by a control unit 71 is arranged in a supply line 73 which pneumatically connects the suction chamber 41 in question with the respective suction bores 53, the clock valve in question 74 maintaining the pneumatic connection when the catching device 58 is moved into its catching position interrupts. In a preferred embodiment, the relevant timing valve 74 is designed such that, simultaneously with the interruption of the pneumatic connection between the relevant suction chamber 41 and the respective suction bores 53, a section of the supply line 73 between the relevant timing valve 74 and the respective suction bores 53 is at barometric pressure or with is ventilated at a pressure that is 3% to 10%, preferably 5%, higher than the barometric pressure. The transport speed of the sheets corresponds to a cycle time in which immediately successive sheets reach the position of the at least one stop surface 66 of the catching device 58 protruding from the conveying plane E19 of the suction belt table 19. A switching time of the relevant clock valve 74 is shorter than the cycle time of immediately successive sheets and is preferably in a range between 20 ms and 100 ms, in particular 40 ms. The switching time of the relevant clock valve 74 is the time starting from the time of its actuation until reaching the time at which the relevant clock valve 74 has changed stably from its first operating position to its second operating position. The control unit 71 is preferably designed in such a way that it controls the relevant clock valve 74 by the duration a cycle time earlier before actuation of the catching device 58 in the state that interrupts the pneumatic connection between the relevant suction chamber 41 and the respective suction bores 53.

The advantage of this solution found is that when a stopper is in operation, the first sheet caught by the catching device 58 is not pushed together or crumpled. Rather, the arrangement of at least one clock valve 74 controlled by the control unit 71 in the supply line 73 between the relevant suction chamber 41 and the respective suction bores 53 ensures that the process of catching the at least one feed belt 54 and unavoidable after the detection of the stopper / or a sustained suction effect of the relevant suction chamber 41 is independent.

As already in connection with the 1 until 3 explained, several sheets are fed to the suction belt table 19 by a transport device immediately upstream of the suction belt table 19, these sheets being transported one behind the other along a linear transport route at least in this transport device and on the suction belt table 19, each lying individually, each with a narrow gap to one another. In the preferred embodiment, these sheets are transported by means of several conveyor belts arranged one behind the other in the transport direction T of the sheets, starting from the rotating conveyor belt 18 of the transport device immediately upstream of the suction belt table 19 via at least one transfer belt 44 belonging to the suction belt table 19, which z. B. is designed as a rotating flat belt preferably arranged in the middle region of the conveying plane E19 of the suction belt table 19, with the sheet in the transport direction T after the transfer belt 44 z. B. two ski jump belts 48 arranged parallel to one another z. B. are arranged in the form of revolving endless belts, followed by at least one feed belt 54, in particular designed as a suction belt, and z. B. two brake bands 56 arranged parallel to one another, each designed as a revolving endless belt. At every transition from a revolving endless belt - e.g. B. in a transition between two successive machine units such as from a non-impact printing device 13 or from a dryer 17 or from a suction belt table 19 to a different machine unit, at least one of these machine units having a transport device in the form of a rotating endless belt - too A transport device following the conveyor belt in question in the transport direction T of the sheets consists of a gap in the conveying plane E19 of the sheets that exists in this conveying plane E19 to a rotating deflection roller 76 of the conveyor belt in question and has a large width in the area z in relation to the thickness of the sheets. B. between 1 mm and 5 mm a discontinuity in the mechanical support of the sheets to be transported, this discontinuity particularly at a high transport speed of several thousand sheets per hour, e.g. B. of around 10,000 sheets per hour carries the risk of operational disruption. Because when transporting sheets resting on a rotating belt, there is a risk that the front edge of the sheet in question will be deflected into the discontinuity point in question at the end of the transport route provided by the conveyor belt in question due to its adhesion to the conveyor belt in question, which is deflected there at the end by means of the deflection roller 76 , whereby such a sheet is prevented from being transported further and itself becomes an obstacle for subsequent sheets. This problem exists in particular at all transitions if at least one of the conveyor belts acting at the transition in question has a width extending transversely to the transport direction T of the sheets of at least 25% of the width of the sheets to be transported. In the preferred embodiment, this is z. B. also at the transition from the suction belt table 19 immediately upstream, e.g. B. the transport device belonging to a dryer 17 to this suction belt table 19 is the case.

It is therefore proposed to replace the point of discontinuity in the mechanical support of the sheets to be transported in the conveyor level E19 with a pneumatic pressure force. This is done because at the transition from the z. B. the transport device immediately upstream of the suction belt table 19, a guide device 42 which extends transversely to the transport direction T of the sheets and preferably has a plurality of lifting nozzles 43 arranged in at least one row is arranged on this suction belt table 19. This guide device 42 with its several lifting nozzles 43 is arranged in the transport direction T of the sheets in particular in front of the at least one skid belt 48 at the transition from the transport device upstream of the suction belt table 19 to this suction belt table 19.

14 shows an example of a top view of a section from the z. B. in connection with the 3 suction belt table 19 described. A sheet-shaped substrate, preferably a printing sheet, called sheet 77 for short, is placed on a z. B. a rotating conveyor belt 18 belonging to a dryer 17 is transferred to the suction belt table 19 lying in a conveyor level E19. Below the Conveying level E19 of the suction belt table 19 and preferably flush with this conveying level E19 upwards is a rotating deflection roller 76 which moves the conveyor belt 18 in the transport direction T of the sheets 77 and deflects it at the end of the transport device immediately upstream of the suction belt table 19. During their transition from the transport device immediately upstream of the suction belt table 19 to the suction belt table 19, the sheets 77 must overcome a discontinuity 78 in their mechanical support located in the conveying plane E19. Transferred sheets 77 are z. B. captured by a transfer belt 44 belonging to the suction belt table 19, this transfer belt 44 z. B. is designed as a rotating flat belt arranged in the central region of the conveying plane E19 of the suction belt table 19 and / or as a suction belt. The transfer belt 44 is followed in the transport direction T by the sheets 77 z. B. two ski jump belts 48 arranged parallel to one another z. B. in the form of continuous endless belts.

15 shows schematically and greatly simplified, by way of example, the guide device 42 arranged in a discontinuity point 78 relating to the mechanical support of the sheets 77 to be transported, with at least one lifting nozzle 43, preferably with several lifting nozzles 43, this discontinuity point 78 z. B. is arranged between a rotating conveyor belt 16 belonging to a non-impact printing device 13 and a rotating conveyor belt 18 belonging to a dryer 17. A sheet 77 transported in the transport direction T tends, due to the rotation of the deflection roller 76, to be pulled with its front edge into a gap which is located at the point of discontinuity 78 in the periphery of the deflection roller 76 and extends transversely to the transport direction T of the sheets 77, thus causing an operational disruption cause. Such a point of discontinuity 78 in the mechanical support of the sheets 77 to be transported exists in one 1 digital printing machine shown as an example, transporting sheets 77 horizontally in several positions, e.g. B. at the respective transition to and after the non-impact printing device 13 and at the transition from the dryer 17 to the suction belt table 19.

The 16 until 19 explain the functionality of the guide device 42 arranged in such a discontinuity point 78 with reference to a digital printing machine transporting sheets 77 horizontally at the transition of the sheets 77 from the non-impact printing device 13 to a dryer 17 immediately downstream of the non-impact printing device 13. These explanations also apply analogously to all other positions at which a generic guide device 42 is arranged or at least can be arranged in the relevant machine arrangement, which is preferably designed as a digital printing machine.

16 shows the initial situation for the function of the guide device 42 arranged in the discontinuity point 78. A sheet 77 resting on the rotating conveyor belt 16 belonging to the non-impact printing device 13 reaches the discontinuity point 78 with its front edge at the transition between the sheets 77, for example. B. from the conveyor belt 16 of the non-impact printing device 13 to a conveyor belt 18 of a dryer 17 immediately downstream of the non-impact printing device 13. The guide device 42 has a tapered profile element 79 which extends transversely to the transport direction T of the sheets 77, preferably in shape a squeegee, the tip of this profile element 79 preferably being arranged approximately tangentially directed against the transport direction T of the sheets 77 towards the conveyor belt 16 of the non-impact printing device 13, the tip of this profile element 79 being deflected by the conveyor belt 16 on the rotating deflection roller 76 Non-impact printing device 13 is spaced apart by a gap, this gap being larger in relation to the thickness of the sheets 77 in the area z. B. has between 1 mm and 5 mm. In the profile element 79 there is at least one lifting nozzle 43 which opens in the direction of its tip, through which lifting nozzle 43 at a z. B. activation of the guide device 42 controlled by the control unit 71 in the 17 Air jet indicated by a directional arrow is directed or at least can be directed towards the conveyor belt 16 of the non-impact printing device 13 deflected on the deflection roller 76. In the state of the 17 In the illustrated activated guide device 42, the sheet 77 resting on the conveyor belt 16 of the non-impact printing device 13 has shifted due to the rotation of the deflection roller 76 compared to that in the 16 In the initial situation shown, the gap formed to form the guide device 42 is increasingly approached, with the front edge of the sheet 77 in question continuing to follow the curvature of the deflection roller 76 in a manner that potentially provokes an operational malfunction.

Like from the 18 and 19 As can be seen, when the guide device 42 is activated, the air jet blown out of the at least one lifting nozzle 43 arranged in the profile element 79 flows against the conveyor belt 16 of the non-impact printing device 13, which is deflected on the deflection roller 76. This air jet hits the conveyor belt 16 in this way that the direction of the core jet of this air jet intersects the circular circumferential line of the deflection roller 76 as a secant. In addition, this air jet is directed onto the conveyor belt 16 directed that a free upper limit of this air jet facing the front edge of the relevant sheet 77 neither intersects nor exceeds a tangent between the circumferential line of the deflection roller 76 and the relevant lifting nozzle 43 of the guide device 42. The air jet directed against the convex surface of the conveyor belt 16 of the non-impact printing device 13, which is deflected on the deflection roller 76, is directed there by the curvature of the deflection roller 76 in the direction of the approaching front edge of the sheet 77 in question. This air jet, which follows the curvature of the deflection roller 76 due to the Coanda effect and is converted into a wall flow, finally detaches the front edge of the relevant sheet 77 from the conveyor belt 16 of the non-impact printing device 13 ( 18 ) and, as the deflection roller 76 continues to rotate, the front edge of the sheet 77 in question lifts more and more away from the conveyor belt 16 of the non-impact printing device 13 due to the resulting dynamic pressure ( 19 ), so that the front edge of the sheet 77, which is still largely resting on the conveyor belt 16 of the non-impact printing device 13, is lifted onto the profile element 79 and thus onto the guide device 42 during its further transport.

After the front edge of the relevant sheet 77 rests securely on the profile element 79, the guide device 42 z. B. preferably deactivated by the control unit 71 by switching off the air jet flowing out of the at least one siphon nozzle 43. The air jet flowing out of the at least one lifting nozzle 43 is therefore preferably active in a clocked manner, this cycle being synchronized with the arrival of the front edge of the respective sheet 77 at the deflection roller 76 of the conveyor belt 16 deflected by means of this deflection roller 76. An air jet flowing out of the at least one lifting nozzle 43 of the guide device 42 is therefore preferably only maintained until the front edge of the respective sheet 77 passes the gap at the point of discontinuity 78 which is located in the periphery of the deflection roller 76 and extends transversely to the transport direction T of the sheets 77 and the front edge of the respective sheet 77 has been lifted onto the profile element 79 of the guide device 42.

This results in a machine arrangement with several processing stations each processing sheets 77, these processing stations being arranged one behind the other in the transport direction T of the sheets 77, with at least one of these processing stations having a first transport device which transports the sheets 77 along a linear transport route with at least one on a rotating deflection roller 76 deflected endlessly revolving conveyor belt 16, this first transport device being designed to transport successive individual sheets 77 in a sequence, each lying on its at least one conveyor belt 16, this processing station having the first transport device also having the sheets 77 on at least one endlessly revolving conveyor belt 18 lying along a linear transport route transporting second transport device or a suction belt table 19 is arranged downstream, whereby at the point of a transfer of the sheets to be transported 77 from the conveyor belt 16 of the first transport device either to the conveyor belt 18 of the second transport device following in the transport direction T of the sheets 77 or to the suction belt table 19 in a conveyor plane E19 of these sheets 77 to be transported, a point of discontinuity 78 is formed in the mechanical support of these sheets 77 to be transferred, the deflection roller 76 deflecting the at least one conveyor belt 16 of the first transport device being at the point of discontinuity 78 in the mechanical support the sheet 77 to be handed over is arranged. At this point of discontinuity 78, a guide device 42 with a tapering profile element 79 is arranged which extends transversely to the transport direction T of the sheets 77, the tip of this profile element 79 being directed against the transport direction T of the sheets 77 towards the conveyor belt 16 of the first transport device, whereby in At least one lifting nozzle 43 is arranged on the profile element 79, the lifting nozzle 43 in question being designed to open out in the direction of the tip of this profile element 79. The tip of the profile element 79 is spaced from the conveyor belt 16 of the first transport device, which is deflected on the rotating deflection roller 76, by a gap, this gap having a greater width in the range between 1 mm and 5 mm in relation to the thickness of the sheets 77. In a preferred embodiment, a plurality of lifting nozzles 43 are arranged in the profile element 79 in a row extending transversely to the transport direction T of the sheets 77. At a z. B. activated by a control unit 71 of the guide device 42, an air jet flowing out of the mouth of the respective lifting nozzle 43 is directed or at least directed towards the conveyor belt 16 of the first transport device, which is deflected on the deflection roller 76, this air jet being directed towards the conveyor belt 16 in this way, that a core jet of this air jet intersects the circumferential line of the deflection roller 76 as a secant. The air jet in question is also aligned in particular in such a way that a free upper limit of this air jet facing a front edge of a sheet 77 transported on the conveyor belt 16 of the first transport device is a tangent between the circumferential line of the deflection roller 76 and the relevant lifting nozzle 43 of the guide device 42 cuts still exceeds. The guide device 42 is activated by the control unit 71. The control unit 71 activates the guide device 42 z. B. clocked, this cycle being synchronized with the arrival of the front edge of the respective sheet 77 on the deflection roller 76 of the conveyor belt 16 of the first transport device, which is deflected by means of this deflection roller 76. The guide device 42 is therefore preferably designed to maintain the air jet flowing out of the relevant lifting nozzle 43 only until the front edge of the respective sheet 77 passes the gap at the point of discontinuity 78 which is located in the periphery of the deflection roller 76 and extends transversely to the transport direction T of the sheets 77 and the front edge of the respective sheet 77 has been lifted to the tip of the profile element 79 of the guide device 42 by the air jet flowing out of the relevant lifting nozzle 43. The deflection roller 76 deflecting the at least one conveyor belt 16 of the first transport device and the guide device 42 together with its profile element 79 are each arranged below the conveying plane E19 of the sheets 77 to be transported and preferably flush with this conveying plane E19 at the top. Since the machine arrangement is designed in its preferred embodiment as a digital printing machine, the processing station having the first transport device is designed either as a non-impact printing device 13 or as a dryer 17 or as a cooling section.

When passing through a z. B. drying by hot air and / or by IR radiation dryer 17, sheets lying flat on a conveyor belt 18, previously printed in a non-impact printing device 13, are subjected to a very high heat input, which results in these dried sheets deform, ie in particular bulge, and thereby at least partially lose their flatness. A bulging of the dried sheets can reach such dimensions that the sheet in question loses its adhesion to the conveyor belt 18 of the dryer 17 and is at least no longer transported in the correct position. As a result, bulging sheets provided at the exit of the dryer 17 can be taken from a transfer belt 44 of a transport device immediately downstream of the dryer 17 in the transport direction T of the sheets, which z. B. belongs to a suction belt table 19 or to a cooling section, can no longer be reliably taken over due to inadequate detection, which very quickly leads to a malfunction in a machine arrangement with several transport devices, especially if such sheets have a transport speed of several thousand sheets per hour, e.g. B. of around 10,000 sheets per hour follow one another. The reason for the inadequate detection of the bulging sheets is, in particular, that the bending resistance forces inherent in the curvature of the relevant sheets are not overcome by a height-dependent suction force exerted by a suction belt. This problem of the unreliable takeover of sheets that are bulging in their edge area, in particular on their respective front edge, by a suction belt can also occur in the conveying plane E19 of the suction belt table 19 at a bend 46; 47 occur, at which a curvature of the previously z. B. horizontal conveying level is formed ( 2 and 3 ). However, in order to avoid damage to a printed image previously applied in the non-impact printing device 13 on the top side of the sheet in question, it is forbidden to force arched sheets to be flat from above at the points mentioned in the machine arrangement described here, e.g. B. by means of a mechanical hold-down device.

In order to produce a required frictional connection or adhesion from a bow that is arched up, in particular due to heat input, to a suction belt and to transport this bow with the suction belt in a precise position, it is proposed to examine the physical appearance of the aerodynamic paradox, in particular with reference to the lateral edge regions of a highly arched front edge of one of a sheet to be taken over by a suction belt and/or a sheet to be transported by a suction belt.

The solution found is explained using the previously described suction belt table 19 as an example. 20 shows an enlarged section of the one in the 3 Suction belt table 19 shown in a plan view, this section focusing in particular on an arrangement of nozzles 49 in an area between one of the two skid belts 48 arranged parallel to one another in the transport direction T of the sheets and a conveyor plane E19 of the suction belt table running longitudinally to the transport direction T of the sheets 19 refers to the laterally delimiting edge 94. The jump belts 48, like the at least one takeover belt 44 arranged upstream of them in the transport direction T of the sheets, are preferably designed in the form of revolving endless belts, in particular each as a suction belt, the suction belt in question being in a pneumatic operative connection with a suction device 72 and as a result of it at least Sectional perforation can exert a suction force on a sheet lying on it. The transport direction T of the sheets is in the 20 indicated by a directional arrow. A blowing direction of the nozzles 49 arranged in the aforementioned area, ie a flow direction of an air stream emerging from these nozzles 49, is z. B. directed in the transport direction T of the sheet. In a preferred and in the 20 In the embodiment shown, the blowing direction of the nozzles 49 arranged in this area is either orthogonal to the edge 94 that laterally delimits the conveying plane E19 of the suction belt table 19 or is inclined at 45 ° in the transport direction T of the arc to the edge 94 that laterally delimits the conveying plane E19 of the suction belt table 19. It can also advantageously be provided that the blowing direction of a first subset of the nozzles 49 z. B. orthogonal to the edge 94 laterally delimiting the conveying plane E19 of the suction belt table 19 and the blowing direction of a second subset of the nozzles 49 z. B. the sheet is inclined by 45 ° in the transport direction T towards the edge 94 that laterally delimits the conveying plane E19 of the suction belt table 19.

21 shows an excerpt from the in the 2 shown side view of the suction belt table 19. It is provided that sheets fed to the suction belt table 19, in particular from a dryer 17, are to be captured by at least one transfer belt 44 and further transported in the conveying plane E19 of the suction belt table 19. In particular in the area of the at least one take-over belt 44 and in the area of the jump belts 48 of the suction belt table 19 downstream of the at least one take-over belt 44 in the transport direction T of the sheets or in the transport direction T of the sheets directly following a point of discontinuity 78 in the mechanical support of the sheets to be transported, for example . B. between the at least one transfer belt 44 belonging to the suction belt table 19 and a rotating conveyor belt 18 belonging to a dryer 17, several nozzles 49 are arranged ( 3 and 20 ). These nozzles 49 are designed in particular as Venturi nozzles and are connected to a compressed air source 93 by means of a pneumatically connecting supply line 96. In a preferred embodiment, a control valve 97 for adjusting and/or regulating the pressure of an air stream flowing out of the respective nozzle 49 is arranged in the supply line 96 connecting at least one of the nozzles 49 to the compressed air source 93. In a particularly advantageous embodiment, a z. B. clock valve 74 controlled by the control unit 71 is arranged. Such a timing valve 74 is preferably controlled by the control unit 71 in such a way that at least one of the nozzles 49 is supplied with compressed air at exactly the moment when the front edge of a sheet to be transported overlaps with the relevant nozzle 49. The application of compressed air to the relevant nozzle 49 is interrupted again by the control unit 71, in particular when the front edge of the relevant sheet to be transported is brought into overlap by a nozzle 49 next in the transport direction T of the sheets. Furthermore, it is provided that the application of compressed air to the nozzles 49 arranged in the floor plan of a sheet to be caught is interrupted by means of the relevant clock valve 74 when the catching device 58 of the suction belt table 19 is switched to its catching position.

This results in a suction belt table 19 with at least one endlessly rotating transfer belt 44 designed as a suction belt for taking over sheets transported individually in a conveyor level E19 from a conveyor belt 18 of a dryer 17 which is immediately upstream of the suction belt table 19 in the transport direction T of the sheets, the suction belt table 19 being in its conveying plane E19 has an arrangement of several nozzles 49 at least in an area between the at least one transfer belt 44 extending longitudinally to the transport direction T of the sheets and an edge 94 laterally delimiting the conveying plane E19 of the suction belt table 19, these nozzles 49 each being designed as Venturi nozzles , wherein a flow direction of at least a first subset of the nozzles 49 arranged in the said area is directed in the transport direction T of the sheets and / or wherein a flow direction of at least a second subset of the nozzles 49 arranged in the said area is orthogonal to the conveying plane E19 of the Suction belt table 19 is directed towards the laterally delimiting edge 94 and/or wherein a flow direction of at least a third subset of the nozzles 49 arranged in the said area is directed at an angle of 45° to the transport direction T of the sheet to the edge 94 which laterally delimits the conveying plane E19 of the suction belt table 19 . In addition, in the conveying plane E19 of the suction belt table 19 in the transport direction T of the sheet, at least one bend 46; 47 can be formed, with each of these kinks 46; 47 the conveying plane E19 of the suction belt table 19 experiences a downward inclination with an acute angle in the range between 5 ° and 30 ° compared to the previous orientation of the conveying plane, the conveying plane E19 being in the area between the at least one transfer belt 44 and the relevant one of the suction belt table 19 laterally delimiting edge 94 formed arrangement of the nozzles 49 in the transport direction T of the sheet over the relevant bend 46; 47 extends beyond. In the area mentioned or in the areas following one another in the transport direction T of the sheets, the nozzles 49 are each z. B. in several, each transverse to the transport direction T arranged in rows extending across the arch ( 3 and 20 ).

The nozzles 49 are each connected to a compressed air source 93 by means of a pneumatically connecting supply line 96, with in at least one of the supply lines 96 connecting at least one of the nozzles 49 to the compressed air source 93, preferably a control valve 97 for adjusting and / or regulating the pressure of one of the respective nozzle 49 outflowing air flow is arranged. In a preferred embodiment, a timing valve 74 is arranged between the relevant control valve 97 and the relevant nozzle 49 in the feed line 96 connecting at least one of the nozzles 49 to the compressed air source 93. The relevant control valve 97 and/or the relevant clock valve 74 are controlled by a control unit 71. The relevant clock valve 74 is activated by the control unit 71 in particular when there is an overlap of the front edge of a sheet to be transported with the relevant nozzle 49. The relevant clock valve 74 is deactivated by the control unit 71 in particular when the front edge of the relevant sheet to be transported is brought into overlap by a nozzle 49 closest in the transport direction T of the sheets. In a particularly preferred embodiment, the suction belt table 19 has a catching device 58 with the previously described features for sheets to be caught, the relevant clock valve 74 being deactivated by the control unit 71 when the catching device 58 is switched to its catching position.

Since the nozzles 49 are each designed as a Venturi nozzle, they generate a suction force acting on a sheet to be transported, which is many times greater in magnitude than a holding force generated by the suction flow on a suction belt arranged in the conveying plane E19 of the suction belt table 19 is provided for holding a sheet lying flat on the suction belt in question. In addition, a width of the area having the arrangement of nozzles 49, which extends transversely to the transport direction T of the sheets, is designed to be significantly larger than the width of the suction belt in question which extends transversely to the transport direction T of the sheets, so that the width of the suction belt in question lies outside the width of the suction belt in question the arrangement of nozzles 49 has a significantly more favorable relationship to the width of the highly arched front edge of the sheet in question. As a result, an effective area formed by the arrangement of the nozzles 49 and acting on the highly arched front edge of the relevant sheet is significantly larger than the effective area acting by the relevant suction belt on the highly arched front edge of the relevant sheet. However, the larger the respective effective area, the easier it is to overcome the bending resistance forces inherent in the curvature of the arch in question. Since the effect of the suction flow of the suction belt in question depends on the height and increases with increasing height, i.e. H. As the distance between the suction belt in question and the sheet to be transported decreases more and more, the nozzles 49 designed as Venturi nozzles can cause the highly arched front edge of the sheet in question to be sucked in until the front edge in question comes into the effective range of the suction flow of the suction belt in question. After the highly arched front edge of the relevant sheet is located sufficiently deep in the effective range of the suction flow of the relevant suction belt due to the action of the nozzles 49, this suction flow may be strong enough to push the highly arched front edge of the relevant sheet over the remaining height to the relevant suction belt to suck it in and to create the frictional connection or adhesion necessary for the precise positioning of the sheet in question. In a preferred embodiment, the control unit 71 is designed in such a way that it first applies compressed air to the nozzles 49 and only then, i.e. H. A suction force exerted on the sheet by the at least one take-over belt 44, each designed as a suction belt, begins to act with a time delay.

Reference symbol list

01

Sheet feeder

02

first batch

03

suction head

04

first swing gripper

05

first coating device

06

Transport cylinder

07

Printing cylinder

08

Applicator roller

09

squeegee; Chamber doctor system

10

-

11

first gripper system

12

Conveyor belt

13

Non-impact printing facility

14

first dryer

15

-

16

Conveyor belt

17

second dryer

18

transport facility; Conveyor belt

19

Suction belt table

20

-

21

second swing gripper

22

second coating device

23

Transport cylinder

24

Printing cylinder

25

-

26

Applicator roller

27

squeegee; Chamber doctor system

28

second gripper system

29

Display

30

-

31

third dryer

32

second stack

33

transfer drum

34

transfer drum

35

-

36

Front mark

37

blow box

38

bulkhead plate

39

opening

40

-

41

suction chamber

42

Guidance device

43

siphon nozzle

44

Takeover band

45

-

46

first kink

47

second kink

48

ski jump band

49

jet

50

-

51

Catch blower

52

switching range

53

Suction hole

54

feed belt

55

-

56

Brake band

57

Suction roller

58

Catching device

59

drive

60

-

61

Piston rod

62

crank

63

paddock

64

Train

65

-

66

stop surface

67

opening

68

floor chamber

69

Storage chamber

70

-

71

Control unit

72

Suction device

73

supply line

74

Clock valve

75

-

76

deflection roller

77

arc

78

discontinuity point

79

Profile element

80

-

81

Pneumatic cylinder

82

cylinder piston

83

End position damping element

84

End position damping element

85

-

86

first pneumatic switching valve

87

second pneumatic switching valve

88

Pressure reducer

89

Pressure reducer

90

-

91

Throttle valve

92

Throttle valve

93

Compressed air source

94

edge

95

-

96

supply line

97

control valve

a

acceleration

F

Piston force

i

gear ratio

M

Centerline

t

Time

T

Transport direction

v

speed

e.g

travel

A51

Distance

B19

Width

D62

pivot point

E1

End point

E2

End point

E19

funding level

G61

Articulation point

G62

Articulation point

G63

Straight

G64

Straight

Claims (10)

Suction belt table (19) for the horizontal transport of individual sheet-shaped substrates in a conveying plane (E19), characterized in that the suction belt table (19) has a catching device (58) and at least one skid belt (48), the catching device (58) and the at least one Ski jump conveyor (48), each controlled by a control unit (71), is designed to assume one of two different operating states, the first operating state being an inactive operating state and the second operating state being an activated operating state, the safety device (58) being in its activated state at least has a stop surface (66) for substrates to be caught, which is set up perpendicular to the conveying plane (E19) of the suction belt table (19), the at least one skid belt (48) extending in the transport direction (T) of the substrates by at least one in the transport direction (T) of the substrates extending substrate length is arranged in front of the at least one stop surface (66) set up perpendicular to the conveying plane (E19) of the suction belt table (19), the at least one skid belt (48) in its activated state with its end directed in the transport direction (T) of the substrates in one The acute angle opening in the transport direction (T) of the substrates is pivoted obliquely upwards out of the conveying plane (E19) of the suction belt table (19). Suction belt table (19). Claim 1 , characterized in that the suction belt table (19) is arranged between a transport device arranged upstream in the transport direction (T) of the substrates and a correspondingly downstream transport device, the transport device arranged upstream of the suction belt table (19) having a translational transport path for the sheet-shaped substrates to be transported individually and/or that the transport device downstream of the suction belt table (19) has a rotary transport path for the sheet-shaped substrates to be transported. Suction belt table (19). Claim 1 or 2 , characterized in that in the transport direction (T) of the substrates between the set up stop surface (66) of the catching device (58) and the at least one swiveled obliquely upwards from the conveying plane (E19) of the suction belt table (19) at the acute angle A catch blower (51) with a plurality of blowing nozzles arranged in a row extending transversely to the transport direction (T) of the substrates is arranged in the area extending above the conveyor belt (48) above the conveying plane (E19) of the suction belt table (19), the catch blower (51) being in its position activated state blows air from its blowing nozzles in the direction of the conveying level (E19) of the suction belt table (19). Suction belt table (19). Claim 1 or 2 or 3 , characterized in that the control unit (71) actuates the catching device (58) depending on a disturbance that has occurred along the transport route belonging to the transport device downstream of the suction belt table (19) in such a way that the catching device (58) has its at least one stop surface (66) for substrates to be caught perpendicular to the conveying plane (E19) of the suction belt table (19) and / or that this control unit (71) sets up the at least one skid belt (48) depending on the transport route that occurs along the transport route belonging to the transport device downstream of the suction belt table (19). Malfunction is actuated in such a way that the at least one skid belt (48) is pivoted obliquely upwards out of the conveying plane (E19) of the suction belt table (19) at the acute angle and/or that this control unit (71) controls the catch blower (51) depending on the along the fault that has occurred on the transport route belonging to the transport device downstream of the suction belt table (19) in such a way that the catch blower (51) blows air from its blowing nozzles in the direction of the conveying plane (E19) of the suction belt table (19). Suction belt table (19). Claim 1 or 2 or 3 or 4 , characterized in that in Transport direction (T) of the substrates after the catching device (58) above the conveying level (E19) of the suction belt table (19), a blow box (37) of an undercutting device belonging to the suction belt table (19) is arranged. Suction belt table (19). Claim 2 or 3 or 4 or 5 , characterized in that in the transport direction (T) of the substrates in front of the at least one skid belt (48) at the transition from the transport device arranged upstream of the suction belt table (19) to this suction belt table (19) there is a guide element (19) which extends transversely to the transport direction (T) of the substrates ( 42) is arranged with several lifting nozzles (43). Suction belt table (19). Claim 1 or 2 or 3 or 4 or 5 or 6 , characterized in that in the transport direction (T) of the substrates between the set up stop surface (66) of the catching device (58) and the at least one swung obliquely upwards at the acute angle out of the conveying plane (E19) of the suction belt table (19). At least one suction chamber (41) is arranged in the area extending from the jump belt (48) below the conveying plane (E19) of the suction belt table (19), the respective suction chamber (41) being set or at least adjustable in its respective pressure by the control unit (71), whereby A negative pressure is set or at least adjustable from the control unit (71) through suction bores (53) formed in the conveying plane (E19) of the suction belt table (19) to the relevant suction chamber (41) in the conveying plane (E19) of the suction belt table (19). Suction belt table (19). Claim 7 , characterized in that the negative pressure set in the conveying plane (E19) of the suction belt table (19) by means of the suction chamber (41) is switched off in the event of a fault occurring along the transport route belonging to the transport device downstream of the suction belt table (19). Suction belt table (19). Claim 2 or 3 or 4 or 5 or 6 or 7 or 8th , characterized in that the control unit (71) is designed such that it reduces a transport speed of the substrates at least in the transport device upstream of the catching device (58) in the transport direction (T) of the substrates. Suction belt table (19). Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8th or 9 , characterized in that in the transport direction (T) of the substrates, two skid belts (48) arranged parallel to one another are provided in the form of revolving endless belts, these two skid belts (48) being symmetrical to the center line (M) of the conveying plane (E19) of the suction belt table (19) are arranged.

Images