Feeder of a sheet-processing machine, and method for operating a feeder of a sheet-processing machine
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- KOENIG & BAUER AG
- Filing Date
- 2024-05-23
- Publication Date
- 2026-04-22
Smart Images
Figure EP2024064221_20022025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Feeder of a sheet-processing machine and method for operating a feeder of a sheet-processing machine
[0003] The invention relates to a feeder of a sheet-processing machine and a method for operating a feeder of a sheet-processing machine.
[0004] In sheet-processing machines, it is generally customary to position the sheets to be processed as a stack on a raising and lowering stacking table, and to separate the sheets from the top of the stack and discharge them in an underlapped stream as an overlapping stream. For this purpose, a sheet separator is assigned to the top of the sheet stack. This separator's working elements, such as separating suction cups, transport suction cups, or a sensor foot, grasp the topmost sheet in the stack in time with the sheet-processing machine, separate it from the following sheet, and convey it in one direction. The blower and / or suction air flow that supports the grasping, separating, and conveying of the sheets is controlled by valve units that are also adjusted in time with the sheet-processing machine's working cycle.
[0005] When separating the sheets from the stack, the sheet is first loosened on all sides at the feeder by so-called blowers that blow continuously. After suction by separating suction cups and separation by strippers, a blast of separating air is required to freely separate the upper sheet from the stack. Along with numerous other elements and parameters, the blast of separating air is crucial for the quality of the sheet travel, especially for substrates with grammages of less than 135 grams per square meter. The direction, quality, quantity and control of the separating air significantly influence the sheet travel and the production output. In state-of-the-art solutions, the supplied separating air is mainly controlled by cam-controlled piston valves or rotary valves. The required volume of separating air must be large enough to create an air cushion under the entire sheet to be separated.
[0006] The volume of separating air that is introduced with each separating air blast under each sheet can be influenced by the blowing pressure and blowing duration.
[0007] To generate a sufficiently large volume of separation air, the state-of-the-art solutions operate with nominal pressures in the range of 1.2–1.4 bar, and the separation air blast continues when the transport vacuum begins its movement cycle to remove the respective sheet. Higher pressures were avoided due to concerns that the sheet might deform.
[0008] DE 198 15 104 A1 discloses a sheet separator in sheet feeders for separating and feeding each top sheet of a sheet stack with separating suction cups that grasp the top sheets in the conveying direction in the rear area and lift them off approximately perpendicular to the sheet stack, and transport suction cups that take up the sheets lifted off by the separating suction cups and transport them in the conveying direction, as well as with a sensor foot that rests in the rear area of the sheet stack after the top sheet has been separated.
[0009] DE 102005 054 138 A1 describes a printing press for printing sheets, comprising a feeder and printing units. The feeder has a separating blower or a loosening blower.
[0010] From DE 102020 107 836 B4 a sheet processing machine with a
[0011] A feeder, a delivery, and one or more offset printing units and / or coating units arranged between the feeder and the delivery. The feeder includes a stacking area with a stack support. In the stacking area, the separation of the top sheet from the sheet stack is assisted by blown air from separating blowers or by blown air from a scanning foot.
[0012] DE 102011 120475 A1 discloses a sheet feeder with two suction wheels. For separation, a sheet at the top of the stack is lifted, and separating air is blown between the raised sheet and the sheet stack in a defined manner. The upper sheet is thus separated from the sheet stack and lifted to an overhead suction wheel by the separating air.
[0013] DE 44 36 720 A1 describes a device for separating sheet material, comprising a support plate for a stack of sheets. A lifting device with a suction nozzle separates the sheets from the stack one after the other, and a conveyor conveys the sheets one after the other, pre-lifted by the lifting device. A blower nozzle is provided for separating the sheets, allowing air to be blown underneath the raised sheets.
[0014] The air blast times implemented in conventional solutions, which usually span a range of 150 to 210 degrees per machine cycle, encompassing 360 degrees, excite the sheet, causing it to oscillate, generating waves, vibrations, and unrest. The sheet is therefore no longer flat, inevitably shortened irregularly by the waves, and causes an irregular sheet stack on the conveyor table. As the machine speed increases, the shingling of the sheets becomes increasingly inaccurate, and sheets protrude from the stack. This results in line problems and, ultimately, stoppages.
[0015] The invention is based on the object of creating a feeder of a sheet-processing machine and a method for operating a feeder of a sheet-processing machine.
[0016] In particular, it is an object of the invention to provide a feeder of a sheet-processing machine and a method for operating a feeder of a sheet-processing machine which enable a smoother and, in particular, more uniform sheet travel with reduced wave formation.
[0017] The object is achieved according to the invention by the features of claim 1 and 16 respectively.
[0018] The advantages achievable with the invention are, in particular, that the functional reliability with which the feeder separates sheets from a stack of sheets is increased.
[0019] In particular, the quality and uniformity of the scaling and staggering can be improved.
[0020] According to one embodiment, the flow velocity of the blown air ejected from outlet openings can be adjusted more precisely.
[0021] The advantage of a further embodiment can also be that the supply of separating air no longer has to be dependent on the speed of the production operation.
[0022] An embodiment of the invention is illustrated in the drawings and is described in more detail below.
[0023] It shows:
[0024] Fig. 1 is a schematic representation of a feeder with an indication of a transport path leading to one or more downstream processing units;
[0025] Fig. 2 a detailed representation of a sheet separator of the feeder with a blowing device.
[0026] The invention is described using the example of a feeder 01 of a sheet-processing machine, also referred to as a machine for processing substrate sheets 03 or sheet-processing machine, which can be designed as a printing press, in particular as a sheet-fed offset printing press.
[0027] A printing press, in particular a sheet-fed offset printing press, comprises, in addition to the feeder 01 for providing, for example, sheet-shaped substrate, in particular substrate sheet 03, or sheet 03 for short, a plurality of printing units, in particular offset printing units, arranged one behind the other in the substrate path and printing in particular on the same substrate side, and a product delivery, e.g. a stack delivery. In addition, it can also comprise one or more coating units in the substrate path. Instead of several printing units, exactly one printing unit can be provided. The printing press can also be a turning device that enables double-sided printing, with all printing units upstream of the turning device in the substrate path printing on one side of the substrate and all printing units downstream of the turning device in the substrate path printing on the other side of the substrate.
[0028] The printing units each comprise a forme cylinder, which is driven, for example, either via a gear train by a main drive (not shown) driving the plurality of printing units, or by a drive motor mechanically independent of the main drive. During production operation, which corresponds to the printing operation, the forme cylinders interact with one or more inking rollers of an inking unit and preferably with at least one dampening roller of a dampening unit. The invention is not limited to sheet-processing machines designed as printing presses, but can be used on all types of sheet-processing machines or be a component thereof.
[0029] In a preferred embodiment, the sheet-processing machine can be designed as a machine that mechanically processes sheets 03, e.g., embossing, cutting, or especially punching, with one or more units that mechanically process the sheets 03, e.g., with at least one punching or embossing unit or a stripping unit.
[0030] In an advantageous further development of the machine, it can also be designed as a hybrid machine, a sheet-forming machine with at least one punching or embossing unit and, in addition, at least one printing unit arranged upstream of the punching or embossing unit in the substrate or transport path. The product delivery, e.g., the stack delivery of such a machine, can also be designed to deliver bundles formed from sheets.
[0031] Further units such as a dryer, a coating unit, a calendering unit or other units acting on the sheets 03 can be provided in the transport path.
[0032] On the output side of the feeder 01, viewed in a transport direction T, there is a conveying device 02, preferably in the form of a belt table 02, in particular a suction belt table 02, which takes the sheets 03 to be conveyed from the feeder 01 and, if appropriate, feeds them downstream via further conveying devices to a single or first unit or assembly of the machine. The belt table 02 is designed, for example, as a suction belt table 02 and preferably comprises at least two rollers 19, of which only one is shown as the first viewed downstream, and of which one is designed as a drive roller 19 and one or more others as deflection rollers. A one-part or multi-part table plate 21 extends between the rollers 19 and forms, for example, the multi-perforated upper side of a suction box 22.The two rollers 19 are wrapped by at least one conveyor belt 23 which, like the table plate 21 over which it extends, is perforated multiple times so that it is not sucked onto the table plate 21, but a sheet 03 is sucked onto the conveyor belt 23. In the area where sheets 03 to be conveyed run up, above the inlet-side roller 19 of the belt table 02 arranged downstream of the feeder 01, a roller 24, e.g. a timing roller 24, which interacts with the roller 19 or the belt table 02 and presses the incoming sheets 03 against the belt table 02 in time with the incoming sheets 03.
[0033] In the feeder 01, a stack 07, in particular a sheet stack 07, is placed on a stacking table 06 provided in a stacking space 04. The stacking table 06 can be raised and lowered, in particular height-adjustable, for example with the aid of a first controllable drive 05, in order to keep the topmost sheet 03 of the sheet stack 07 at a fixed or only slightly variable height, independent of the number of sheets 03 in the sheet stack 07, suitable for transferring the sheets 03 to the downstream conveyor device 02. In the illustration, the sheets 03 of the sheet stack 07 lie directly on the stacking table 06, but there can also be a pallet between the sheet stack 07 and the stacking table 06, on which the sheet stack 07 has been transported to the stacking table 06 and deposited thereon.
[0034] On the side of the stacking space 04 facing in the transport direction T, a stop device 08, e.g. a single-part or multi-part front stop 08, is provided, the stop surface of which, directed opposite to the transport direction T, defines a vertical plane which serves as a stop for the front edges, i.e. the edges leading during transport, of the sheets 03 of the sheet stack 07. Viewed vertically, this stop device 08 does not reach as far as the upper stack edge, but is continued in its vertical alignment, if required, by a stop surface of an active feed device 11, also referred to in particular as a sheet flap 11. For this purpose, the feed device 11 can be switched between an active position, e.g. a pivoted position, in which it is located with its stop surface in the transport path of a sheet 03 to be conveyed from the feeder 01, and an inactive position, e.g.pivoted position in which it releases the transport path intended for transport, displaceable, in particular pivotable.
[0035] Although other mechanisms are also conceivable by which the sheet flap 11 can be displaced between the two aforementioned positions, the sheet flap 11 is preferably mounted in the feeder 01 so as to be pivotable about a pivot axis. For this purpose, a support element 12, for example, acting or designed as a shaft 12, e.g., a flap shaft 12, is provided, which supports the sheet flap 11.
[0036] The feeder 01 comprises various transport tools 14; 16 for removing individual sheets 03 from the sheet stack 07 and for transporting the sheets 03 onto or into the conveyor device 02 arranged downstream of the feeder 01. The transport tools 14; 16 are preferably accommodated in or encompassed by a so-called sheet separator 13.
[0037] The transport tools 14; 16 are preferably driven by separately controllable individual drives. The transport tool 14 is provided, in particular, as a separating element 14 for grasping a respective sheet 03 in a separating plane 15 and for displacing the respective sheet 03 into a sheet guide plane 20 vertically spaced from the separating plane 15. The separating element 14 is designed, in particular, as a separating suction device 14, more preferably as a spring suction device 14.
[0038] Preferably, the sheet separator 13 also accommodates or encompasses a transport tool 16 designed as a transport member 16, in particular as a drag suction device 16. The transport member 16 receives a respective sheet 03 from the separating member 14 and transports it in a sheet guide plane 20 in the direction of the conveyor device 02. The separating member 14 and / or the transport member 16 are formed in particular by a single or preferably by a plurality of suction devices 14; 16.
[0039] For example, as a separating device 14, several separating suction cups 14 can be arranged on the sheet separator 13 in the area of a trailing edge of the sheet stack 07 in the transport direction T of the sheets 03 and can be moved essentially in the vertical direction. The trailing edge of the sheet stack 07 or the trailing edges of the sheets 03 represent the beginning of the transport path.
[0040] Furthermore, for example, a plurality of drag suction cups 16 are provided as transport element 16, which are provided on the sheet separator 13 closer to the front stop 08 when viewed in the transport direction T and are movable horizontally in and against the transport direction T. A so-called feeler foot 17 can be provided as a further tool, in particular as a component of the sheet separator 13. The feeler foot 17 can be guided into the profile of the sheet stack 07. Preferably, the feeler foot 17 is driven by a feeler foot gear which moves the feeler foot 17 between an upper and a lower end position, wherein the feeler foot 17 is supported on the upper side of the stack in the lower end position during production. Between the two end positions, the movement of the feeler foot 17 can comprise a horizontal movement component in addition to the vertical, and the feeler foot 17 can in particular execute a pivoting movement.The probe base 17 can also be designed as a blowing nozzle for building up a supporting air cushion or can comprise a blowing nozzle.
[0041] The sheet separator 13 is arranged in the feeder 01, in particular so as to be height-adjustable. A second controllable drive 10 is provided to implement the adjustment movement of the sheet separator 13. In particular, the at least one separating element 14 and / or the at least one transport element 16 and / or the blowing device 18 are components of the sheet separator 13, with a controllable drive 10 for raising and lowering the sheet separator 13 being assigned to the sheet separator 13.
[0042] In order to facilitate the separation of each picked-up sheet 03 from the rest of the sheet stack 07, loosening blowers 26 can be arranged in the region of the top side of the sheet stack 07. The loosening blowers 26 can be arranged on the rear side of the stack, i.e. on the side opposite the transport direction T, in particular the rear edge of the stack 07. In addition to or alternatively to an arrangement on the rear edge of the stack 07 at the beginning of the transport path, loosening blowers 26 can also be arranged on both sides of the sheet stack 07 and designed to generate a blowing air flow directed towards the center of the stack. The loosening blowers 26 form, in particular, a blowing air flow that is continuous during operation of the feeder 01.
[0043] In addition to the loosening blowers 26 or independently, a blower device 18 is provided at the beginning of the transport path, preferably in the area of the rear edge of the stack 07. The blower device 18 is preferably arranged fixedly to the frame, but can also be mounted so as to be height-adjustable or be designed to be height-adjustable together with the sheet separator 13.
[0044] The blowing device 18 has at least one outlet opening 29.
[0045] The blowing device 18 preferably has a plurality of outlet openings 29 arranged at a distance from one another transversely to the transport direction T. The outlet openings 29 are, in particular, components of respective separating air nozzles. The outlet openings 29 can be designed with or without means for selectively interrupting the blowing air supply to the outlet openings 29. In particular, means for interrupting the air supply to individual outlet openings 29 independently of other outlet openings 29 can be provided.
[0046] Further preferably, only the two outer outlet openings 29, as viewed from the center of the transport path, are provided with or cooperate with means for interrupting the air supply, while the outlet openings 29 arranged closer to the center of the transport path do not have or cooperate with means for interrupting the air supply. Instead of the two outer outlet openings 29, groups of outer outlet openings 29 can also be provided with or cooperate with means for interrupting the air supply.
[0047] The outlet openings 29 can all have the same geometry or different geometries. In particular, the outlet openings 29 can be formed with oval geometries or with circular geometries.
[0048] If the outlet openings 29 are formed with circular geometries, the diameter of the outlet openings is preferably less than six millimeters each. In particular, the opening cross-section of the outlet openings 29 can each be thirty square millimeters or less than thirty square millimeters.
[0049] The blowing device 18 can comprise one or more pulse-controlled high-pressure valves. The pulse-controlled high-pressure valves are preferably arranged between a compressed air generator and the outlet openings 29. Each such pulse-controlled high-pressure valve can be assigned exactly one outlet opening 29. Preferably, a plurality of outlet openings 29 are assigned to such a pulse-controlled high-pressure valve. To control the air supply, the blowing device 18 can also comprise one or more cam-controlled valves or rotary slides. In particular, one or more cam-controlled valves or rotary slides can be arranged between a compressed air generator and one or more outlet openings 29.
[0050] The blowing device 18 is designed for a sheet sequence to generate blasts of air. Depending on the design and arrangement of the blowing device 18, the blasts of air are directed at least approximately in the transport direction T.
[0051] To separate sheets 03 from the sheet stack 07, a respective uppermost sheet 03 in the sheet stack 07 is grasped by the separating element 14, in particular by means of a vacuum in the separating plane 15, and then transported, in particular lifted, into the sheet guide plane 20, which is vertically spaced from the separating plane 15. It is sufficient if the respective uppermost sheet 03 is lifted on the side of the sheet stack 07 facing away from the transport path downstream of the sheet stack 07.
[0052] The blowing device 18 emits exactly one blast of air for each sheet 03 transported from the singulation plane 15, which blast is directed beneath the sheet 03. In other words, the emission of blasts of air by the blowing device 18 is timed such that the blowing device 18 is triggered to emit a respective blast of air when a respective sheet 03 has passed the blowing device 18 vertically on its way into the sheet guide plane 20.
[0053] A respective blast of air begins either immediately before the respective sheet 03 has arrived at the sheet guide level 20 or exactly when the respective sheet 03 has arrived at the sheet guide level 20 or shortly after the respective sheet 03 has arrived at the sheet guide level 20. A respective blast of air ends either at a time interval before the start of the transport movement of the transport element 16 for transporting the respective sheet 03 or when the transport movement of the transport element 16 for transporting the respective sheet 03 begins.
[0054] The blowing device 18 is preferably designed to generate blasts of air in sync with the sheet sequence. The sync is defined as an angle of 360 degrees, so that a new sync begins every 360 degrees, and the elements of the feeder 01 moving in sync repeat their movements.
[0055] The duration of the air blasts can be forty-five degrees each and accordingly extend over one eighth of a bar.
[0056] The duration of the air blasts can also range from twenty to seventy degrees or from thirty to sixty degrees.
[0057] The blowing device 18 can also be designed for each sheet 03 of a sheet sequence to generate blowing air blasts, the duration of which is the same for all sheets 03 of the sheet sequence and which therefore does not depend on the machine speed of the feeder 01 or the sheet processing machine.
[0058] In this case, the duration of the air blasts is preferably 25 milliseconds each or is in the range of ten milliseconds to forty milliseconds.
[0059] The blowing device 18 can, in particular, be designed such that in the area of at least one or all of the outlet openings 29, the air pressure of the respective blast of air is equal to or greater than two bar. The air blown between the sheet layers by the blowing device 18 separates the sheet 03 from the sheet stack 07 and forms an air cushion beneath the sheet 03, on which the sheet 03, driven by the horizontal movement of the transport element 16, is pushed over the sheet flap 11, which is then shifted into the inactive position, onto the belt table 02.
[0060] In particular, the blowing device 18 generates a blast of air for each sheet 03 of a sheet sequence, the duration and / or flow velocity of which is the same for all sheets 03 of the sheet sequence.
[0061] List of reference symbols
[0062] 01 Investor
[0063] 02 Conveyor system, belt table, suction belt table
[0064] 03 Substrate sheet, sheet
[0065] 04 Stacking room
[0066] 05 Drive, first
[0067] 06 Stacking table
[0068] 07 Stack, sheet stack
[0069] 08 Stop device, front stop
[0070] 09 -
[0071] 10 Drive, second
[0072] 11 Feeding device, curved flap
[0073] 12 Support element, shaft, flap shaft
[0074] 13 sheet separators
[0075] 14 Transport tool, separating device, separating suction cup, spring suction cup, suction cup
[0076] 15 Separation level
[0077] 16 Transport tool, transport device, drag suction device, suction device
[0078] 17 Button base
[0079] 18 Blowing device
[0080] 19 Roller, drive roller
[0081] 20 arch guide level
[0082] 21 Table sheet
[0083] 22 Suction box
[0084] 23 Conveyor belt
[0085] 24 roller, timing roller
[0086] 25 -
[0087] 26 loosening blowers
[0088] 27 - - Outlet opening transport direction
Claims
Claims 1. A feeder (01) of a sheet-processing machine comprising a stacking table (06) designed to receive a sheet stack (07), at least one separating member (14) by which a sheet stack (07) of the respective uppermost sheet (03) of the sheet stack (07) can be grasped in a separating plane (15) and displaced into a sheet guide plane (20) vertically spaced from the separating plane (15), and at least one transport member (16) by which the respective sheet (03) can be transported in a transport direction (T) away from the sheet stack (07) into a downstream transport path, comprising a blowing device (18), wherein the blowing device (18) is designed for a sheet sequence for generating blowing air blasts, which are each directed in the transport direction (T) under the respective uppermost sheet (03) after its displacement from the separating plane (15),wherein a respective blast of air under the respective sheet (03) ends at a time interval before the beginning of the transport movement of the transport member (16) for transporting the respective sheet (03) or wherein a respective blast of air under a respective sheet (03) ends when the transport movement of the transport member (16) for transporting the respective sheet (03) begins.
2. Feeder according to claim 1, characterized in that the blowing device (18) is designed to generate blasts of air in time with the sheet sequence, each cycle of the sheet sequence comprising three hundred and sixty degrees and the duration of the blasts of air being forty-five degrees each.
3. Feeder according to claim 1 or 2, characterized in that the blowing device (18) is designed to generate blasts of air in time with the sheet sequence, each cycle of the sheet sequence comprising three hundred and sixty degrees and the duration of the blasts of air in each case being in the range of twenty to seventy degrees.
4. Feeder according to claim 1, 2 or 3, characterized in that the blowing device (18) is designed to generate blasts of air in time with the sheet sequence, each cycle of the sheet sequence comprising three hundred and sixty degrees and the duration of the blasts of air in each case being in the range from thirty to sixty degrees.
5. Feeder according to claim 1, 2, 3 or 4, characterized in that the blowing device (18) has at least one outlet opening (29) and the air pressure of the respective blowing air blast in the region of the at least one outlet opening (29) is equal to or greater than two bar.
6. Feeder according to claim 1, 2, 3, 4 or 5, characterized in that the blowing device (18) has at least one outlet opening (29) and the at least one outlet opening (29) has an opening cross-section which is equal to or less than thirty square millimeters.
7. Feeder according to claim 1, 2, 3, 4, 5 or 6, characterized in that the blowing device (18) has a plurality of outlet openings (29) which are arranged spaced apart from one another transversely to the transport direction (T).
8. Feeder according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that the blowing device (18) has a plurality of outlet openings (29), wherein means are provided for interrupting the air supply to individual outlet openings (29) independently of other outlet openings (29).
9. Feeder according to claim 1, 2, 3, 4, 5, 6, 7 or 8, characterized in that the blowing device (18) comprises one or more pulse-controlled high-pressure valves.
10. Feeder according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, characterized in that one or more pulse-controlled high-pressure valves are arranged between a compressed air generator and the at least one outlet opening (29).
11. Feeder according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, characterized in that the blowing device (18) comprises one or more valves or rotary slides controlled by cams.
12. Feeder according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, characterized in that one or more valves or rotary slides controlled by cams are arranged between a compressed air generator and one or the at least one outlet opening (29).
13. Feeder according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, characterized in that the blowing device (18) is designed to generate exactly one blast of blowing air per sheet (03).
14. Feeder according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, characterized in that the transport member (16) is designed to run back and forth in the transport direction (T) and to transport a respective sheet (03) in the sheet guide plane (20).
15. Feeder according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, characterized in that the at least one separating member (14) and / or the at least one transport member (16) and / or the blowing device (18) are components of a sheet separator (13), wherein a controllable drive (10) for raising and lowering the sheet separator (13) is assigned to the sheet separator (13).
16. Method for operating a feeder (01) of a sheet processing machine, in particular of a feeder (01) according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, wherein for a sheet sequence of sheets lying as a sheet stack (07) on a stacking table (06), the respective uppermost sheet (03) in the sheet stack (07) is displaced, at least on the side of the sheet stack (07) facing away from a transport path adjoining the sheet stack (07) downstream, by at least one separating element (14) from a separating plane (15) forming the upper side of the sheet stack (07) into a sheet guiding plane (20) vertically spaced therefrom, and a blast of air directed beneath the raised sheet (03) is generated, wherein a respective blast of air is directed beneath a respective sheet (03) at a time interval from the start of the transport movement of the transport element (16) for transporting the respective sheet (03) or wherein a respective blast of air ends under a respective sheet (03),when the transport movement of the transport element (16) for transporting the respective sheet (03) begins., 17. Method according to claim 16, characterized in that exactly one blast of air is generated for each sheet (03) of a sheet sequence.
18. Method according to claim 16 or 17, characterized in that for each sheet (03) of a sheet sequence a blast of air is generated, the duration of which is the same for all sheets (03) of the sheet sequence.
19. Method according to claim 16, 17 or 18, characterized in that for each sheet (03) of a sheet sequence a blast of blown air is generated, the flow velocity of which is the same for all sheets (03) of the sheet sequence.
20. Method according to claim 16, 17, 18 or 19, characterized in that the duration of each blast of air is in the range of ten milliseconds to forty milliseconds.
21. Method according to claim 16, 17, 18, 19 or 20, characterized in that the blowing device (18) is designed to generate blasts of blown air in time with the arc sequence, each cycle of the arc sequence comprising three hundred and sixty degrees and the duration of the blasts of blown air being forty-five degrees in each case.
22. Method according to claim 16, 17, 18, 19, 20 or 21, characterized in that the blowing device (18) is designed to generate blasts of blown air in time with the arc sequence, each cycle of the arc sequence comprising three hundred and sixty degrees and the duration of the blasts of blown air being in the range of twenty to seventy degrees.
23. Method according to claim 16, 17, 18, 19, 20, 21 or 22, characterized in that the blowing device (18) is designed to generate blasts of blown air in time with the arc sequence, each blast of the arc sequence comprising three hundred and sixty degrees and the duration of the blasts of blown air being in the range of thirty to sixty degrees.