Sheet folding machine with waste sheet discharge device

Abstract

The invention relates to a sheet folding machine with a waste sheet discharge device, comprising: a sheet feeder (2) generating a stream (4) of sheets (3); a first folding station (5) and a further station (6), the first folding station comprising at least one folding grid (12) and at least two folding rollers (11) for folding the sheets; a monitoring device (30), a control device (40), and a discharge device (20), wherein the monitoring device (30) monitors the stream (4) for errors, and the control device (40) activates the discharge device (20) for discharging waste sheets (28) when an error is detected, the monitoring device (30) being arranged at an inlet region (16) of the folding grid (12) and monitoring the stream (4) in the folding grid (12), and the discharge device (20) being arranged downstream of the first folding station (5) and upstream of the further station (6). The invention enables reliable detection and discharge of waste sheets during folding before production can be disrupted, and the invention can be used in industrial folding machines.

Description

Technical Field

[0001] The invention relates to a sheet folding machine with a waste sheet removal device having the features of the preamble of claim 1 .

[0002] The invention belongs to the technical field of the graphics industry and in particular to the technical field of folding printing materials or the production and movement of folded products, preferably made of paper. Background Art

[0003] DE 10 2010 049 057 A1 discloses a sheet folding machine of this type with a waste sheet discharge function / waste sheet discharge device. Specifically, the machine comprises a sheet feeder that generates a flow of sheets, a first folding station, and further stations. The first folding station comprises at least one folding fence and at least two folding rollers for folding the sheets, a checking device / monitoring system, a control device, and a discharge diverter. The monitoring device monitors the flow for errors, and the control device activates the discharge diverter to discharge the waste sheets if an error is detected. The monitoring device is arranged in the area of ​​the infeed table between the sheet feeder and the first folding station; the document does not disclose the specific location of the discharge device. The generated flow of sheets is a slab flow.

[0004] JP2000318921A discloses a folding station with a plurality of folding fences and sensors (eg photoelectric sensors), wherein the sensors are arranged approximately in the middle with respect to the length of the folding fences.

[0005] JP2016132518A also discloses a folding station with a plurality of folding fences and sensors (eg laser sensors), wherein these sensors are also arranged approximately in the middle with respect to the length of the folding fences. Likewise, the sheet flow formed by the sheets is not processed here.

[0006] MBO Postpress Solutions GmbH is promoting a transport table with a sheet ejection device downstream of the first folding unit. Incorrectly folded sheets or double sheets can be ejected. Ultrasonic sensors can be used.

[0007] H+H GmbH & Co. KG is promoting a discharge switch downstream of the folding mechanism. This discharge switch can be controlled by a camera system upstream of the folding mechanism.

[0008] EP1013589A2 discloses a buckle-type folding mechanism and a method for register adjustment of the buckle-type folding mechanism. The method includes a device for detecting a first time point during the operation of a sheet from an inlet into the buckle-type folding mechanism until it reaches a buckle-type stop, a device for detecting a second time point during the operation of a sheet from fold formation to exiting the folding buckle, and a device for determining the required sheet length between the first and second time points. Discharge devices / means are not disclosed.

[0009] JP2010111471A discloses a machine with a folding mechanism comprising multiple folding grates. A seamless web is marked with markings, and the web is transversely cut according to these markings, and the resulting sections are folded. The machine includes sensors for detecting the markings. It also includes sensors for detecting waste sheets and a switchable device for ejecting identified waste sheets.

[0010] EP 2 489 616 A2 discloses a feeder for a printing machine (particularly a buckle folder) and a method for operating such a feeder. The feeder includes a device for detecting multiple sheets. This device may include an ultrasonic sensor. Because waste sheets are to be avoided in this document, no device for discharging waste sheets is disclosed.

[0011] Sheets that are incorrectly folded in one folding station may cause problems in subsequent stations, such as a skew roller table or another folding station, for example due to differences in their lengths, which may necessitate interrupting production. Summary of the Invention

[0012] The object of the present invention is therefore to propose a solution that is improved compared to the prior art and that makes it possible, in particular, to reliably detect and remove waste sheets during folding before production can be disrupted.

[0013] This object is achieved according to the invention by a sheet folding machine with a waste sheet discharge device according to claim 1 .

[0014] Advantageous and therefore preferred developments of the invention are apparent from the dependent claims as well as from the description and the drawings.

[0015] According to the present invention, a sheet folding machine with a waste sheet discharge device includes a sheet feeder, a first folding station and another station, wherein the sheet feeder generates a flow consisting of sheets, wherein the first folding station includes at least one folding fence and at least two folding rollers for folding sheets, the sheet folding machine also includes a monitoring device, a control device and a discharge device, wherein the monitoring device monitors errors in the flow and the control device activates the discharge device for discharging waste sheets when an error is identified, the sheet folding machine is characterized in that: the monitoring device is arranged at the entrance area of ​​the folding fence and monitors the flow in the folding fence, and the discharge device is arranged downstream of the first folding station and upstream of the other station.

[0016] The invention advantageously makes it possible to reliably identify waste sheets during folding and to remove them before production can be disrupted.

[0017] The entry area of ​​the folding barrier is the open front area of ​​the folding barrier, which faces the folding rollers of the folding mechanism. At this entry area, the sheet enters the folding barrier with one sheet edge facing forward in the entry direction. Preferably, an entry lip can be located at this entry area. In the rear area of ​​the folding barrier, the sheet hits an adjustable stop (depending on the fold length) with this sheet edge. The middle area of ​​the folding barrier is located between the entry area and the rear area. The entry area is also the exit area, because here the sheet also exits the folding barrier in the exit direction (opposite to the entry direction).

[0018] During research to improve production, it was discovered that when folding sheets that follow one another in the folding fence, the following problem may occur: the sheet trailing edge of the outgoing, preceding (first) sheet may drag the sheet leading edge of the incoming, following (second) sheet toward the exit, and this may occur particularly in the entry / exit area. Similarly, it was discovered that the sheet leading edge of the incoming, following (second) sheet may drag the sheet leading edge of the outgoing, preceding (first) sheet toward the exit, and this may occur particularly in the entry / exit area. In both cases, this results in incorrect folding or deviation from the rated folding length. The entry / exit area can therefore be understood as an area in which two consecutive sheets pass by one another and potentially interfere with their movement and / or direction of movement.

[0019] The present invention offers the advantage that folding errors are detected at the point and time where they actually occur: in the folding mechanism of the folding machine, there in the folding fence (preferably in the first activated folding fence), and there again in its entry / exit area for the sheets to be folded. Due to this early detection of errors, measures can be taken (without disruptive delays), preferably to discharge the waste sheets directly downstream of the folding mechanism, particularly preferably in the area of ​​the conveyor. This saves valuable time so that the defective sheets can be discharged before they enter further stations downstream. Ultimately, this avoids production stops, reduces waste, increases productivity, and reduces production costs. Achieving extremely high machine speeds, as increasingly required by the industry, is only possible if error detection can also meet the extremely high requirements. The present invention makes a decisive contribution to this.

[0020] The distance between the discharge device and the outlet of the folding mechanism is preferably selected such that, even with long sheet formats and high machine speeds, there is sufficient reaction time for discharging the waste sheets.

[0021] Furthermore, the present invention provides the possibility of detecting different error types and discharging individual sheets or groups of sheets (two or more sheets) accordingly. Such error types may include, for example, the leading edge of a sheet (following sheet) dragging in the inlet area (following sheet), the trailing edge of a sheet (following sheet) dragging in the inlet area (following sheet), and / or incorrect folds (or misfolded sheets).

[0022] The sheet feeder preferably generates a stacked stream of sheets, a so-called fish-scale arrangement, particularly preferably a stacked stream, i.e., the (front) portion of the succeeding sheet is located below the (rear) portion of the preceding sheet. This stacked stream of sheets is fed into the first folding mechanism. The folding in the first folding mechanism breaks up the stacked stream, i.e., the folded sheets leave the first folding mechanism not as a stacked stream, but as successive (preferably spaced) sheets.

[0023] Preferably, the first station is a folding grating station with at least one folding grating. Equally preferably, the other station is a folding grating station, alternatively, for example, a knife folding station (Schwertfalzstation).

[0024] The following describes a preferred development solution (abbreviated as: development solution) of the present invention.

[0025] One embodiment can be characterized in that the inlet region comprises at most 1 / 4, 1 / 5, 1 / 6 or 1 / 10 of the length of the folding barrier. One embodiment can be characterized in that the inlet region comprises at most 150 mm, 130 mm or 110 mm of the length of the folding barrier. One embodiment can be characterized in that the inlet region comprises approximately 100 mm of the length of the folding barrier.

[0026] One development can be characterized in that the folding strip can be selected from a number of available folding strips of different lengths and can be arranged in the first folding station.

[0027] One development may be characterized in that the folding barrier includes an inlet lip, and the inlet region is positioned adjacent to the inlet lip. One development may be characterized in that the inlet region is positioned adjacent to the inlet lip. One development may be characterized in that the inlet lip is positioned adjacent to the two folding rollers. One development may be characterized in that the inlet lip is positioned adjacent to at least one of the two folding rollers.

[0028] One embodiment of the invention can be characterized in that the monitoring device includes an ultrasonic sensor. One embodiment of the invention can be characterized in that the ultrasonic sensor consists of two parts and includes a transmitter and a receiver. One embodiment of the invention can be characterized in that the transmitter and the receiver are oriented orthogonally to the plane of the sheet to be monitored. One embodiment of the invention can be characterized in that the transmitter and the receiver are spaced approximately 40 mm apart from each other. One embodiment of the invention can be characterized in that the ultrasonic sensor detects during monitoring whether one, two or no sheets are located in the folding fence. One embodiment of the invention can be characterized in that the ultrasonic sensor detects in the flow whether single-layer sheets and double-layer sheets appear continuously and alternately. In this state, the waste sheet discharge device can remain deactivated. One embodiment of the invention can be characterized in that the ultrasonic sensor detects in the flow whether a further double layer appears after a double layer within a predetermined time period. In this state, the waste sheet discharge device can be activated.

[0029] A further development can be characterized in that the monitoring device is arranged approximately in the middle of the folding barrier with reference to its width. This arrangement is advantageous, in particular when changing the format width.

[0030] One development can be characterized in that the monitoring device monitors the flow in the folding barrier for at least one of the following errors: a succeeding sheet being dragged by a preceding sheet, a preceding sheet being dragged by a succeeding sheet, and / or incorrectly folded sheets.

[0031] One development can be characterized in that the flow fed to the first folding station is a scaled flow, in particular a bottom-mounted scaled flow.

[0032] One extension may be characterized in that the discharge device is arranged on a conveying device between the first folding station and the further folding station. One extension may be characterized in that the conveying device is constructed as a conveying table with conveying rollers. One extension may be characterized in that the further station is the second folding station. One extension may be characterized in that the discharge device is constructed as a switchable discharge valve. One extension may be characterized in that the discharge valve is pneumatically operated. To this end, the pneumatic cylinder can be activated by a control device that is connected to the monitoring device. One extension may be characterized in that the discharge valve is arranged to be swingable around a horizontal axis. One extension may be characterized in that the discharge valve is closed in a first swing position and opened in a second swing position for waste sheet discharge. One extension may be characterized in that the discharge valve has a first surface, and the first surface is used as a sheet guide element in the first swing position. One extension may be characterized in that the discharge valve has a second surface, and the second surface is used as a discharge element in the second swing position. One development can be characterized in that the discharge flap extends over the entire working width of the transport device and is therefore independent of the (sheet) format.

[0033] An extended solution may be characterized in that the monitoring device comprises an optical sensor. An extended solution may be characterized in that the monitoring device comprises a reflected light sensor, a reflection sensor (Lichttaster), a laser reflection sensor, a light barrier or a camera. An extended solution may be characterized in that the monitoring device comprises an ultrasonic sensor and an optical sensor, preferably a reflected light sensor, wherein both sensors are used during monitoring. An extended solution may be characterized in that the monitoring device comprises a capacitive sensor. An extended solution may be characterized in that the monitoring device comprises an ultrasonic sensor and a capacitive sensor, wherein both sensors are used during monitoring. The advantage of two sensors may be that, for example, the ultrasonic sensor recognizes approximately 90% of all errors, and the other sensor (for example the reflected light sensor or the capacitive sensor) recognizes the remaining 10%.

[0034] The features and feature combinations disclosed in the above sections on the technical field, the summary of the invention and the developments, as well as in the following section on the exemplary embodiments, in any combination with one another, constitute further advantageous developments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 、 Figure 2a 、 Figure 2b and Figure 2c Preferred embodiments and developments of the present invention are shown.

[0036] Corresponding features are provided with the same reference numerals in the drawings. For the sake of clarity, repeated reference numerals in the drawings are partially omitted. DETAILED DESCRIPTION

[0037] Figure 1 A schematic illustration (sectional view) of a preferred embodiment of a sheet folding machine 1 according to the invention is shown, comprising a sheet feeder 2 (e.g., a stack feeder) which generates a scalloped stream 4 from sheets 3, 3a (e.g., paper or cardboard) and feeds this stream 4 to a first folding station 5. The first folding station 5 is preferably designed as a folding station, which can have, for example, up to six folding folding grates. At least one further station 6 (in particular, a second folding station 6, preferably also a folding station) can be arranged downstream of the first folding station 5. A conveyor device 7 (in particular, a conveyor table) is arranged between the two folding stations 5, 6, which has a plurality of conveyor rollers 8 and a hold-down device 9.

[0038] The first folding station 5 has several mounting locations 10 (for folding grids or sheet diverters, which can be installed depending on the folding pattern) and several folding rollers 11. Folds are produced in the sheets 3 using folding grids 12, 13. Each folding grid 12, 13 has an adjustable fold stop 14 for adjusting the respective fold length. Sheets 3 are merely deflected (without being folded) using a sheet diverter 17. Each folding grid 12, 13 has an entry lip 15. The entry lip 15 is located close to the folding roller 11 (in particular, adjacent to the folding roller 11) and ensures smooth entry of the sheets 3 into the folding grids 12, 13.

[0039] The folding barrier 12 has a length 18 in the direction of the sheet entering and exiting the folding barrier; the fold stop 14 is displaceable and therefore adjustable in the direction of this length 18. The area indicated by dashed lines in the figures and designated by the reference numeral 16 forms the inlet area of ​​the folding barrier 12. The inlet area 16 is arranged close to the folding roller 11, in particular adjacent to the folding roller 11.

[0040] The sheet folding machine 1 includes a discharge device 20, preferably configured as a discharge flap 21 having a horizontal (pivoting) axis 22. The discharge flap 21 is pivotally mounted and can pivot back and forth between a first pivot position 23 and a second pivot position 24. The discharge flap 21 preferably includes a first surface 25 and a second surface 26, which can be arranged, for example, at right angles to each other. In the first pivot position 23, all folded sheets 3b are moved past the first surface 25, while in the second pivot position 24, selected sheets 3b are pushed against the second surface 26 and thereby discharged. In this regard, the second surface 26 forms a discharge element 27 for discharging waste sheets 28. Reliable discharge of waste sheets can be facilitated by two discharge rollers 29, preferably arranged below the discharge flap 21. These discharge rollers 29 can be driven, for example, by the last transport roller 8 of the plurality of transport rollers 8 described above in the direction of transport.

[0041] The sheets 3, 3a to be folded (preferably as a bottom-mounted flake stream 4) enter the arrangement assembly (Anordnung) of the folding rollers 11, where they are folded into sheets 3, 3b, 3c through the interaction of the folding fence 12 with the folding rollers 11, and then run as folded sheets 3, 3d along the conveyor device 7 to another station 6 in a folded form and without forming a flake shape.

[0042] According to the invention, the sheet folding machine 1 comprises a monitoring device 30, preferably an ultrasonic sensor 31 having a transmitter 32 and a receiver 33. According to the invention, the monitoring device 30 is arranged at the inlet area 16, preferably in the inlet area 16. For example, the monitoring device 30 can be arranged close to or even very close to the folding rollers 11. As an ultrasonic sensor 31, the monitoring device 30 can be arranged such that the transmitter 32 is arranged above the folding barrier 12 and the receiver 33 is arranged below the folding barrier 12, or vice versa.

[0043] Alternatively, for example, a reflected light sensor 34 can also be provided, which is preferably arranged perpendicular to the plane 35 of the sheet 3 .

[0044] The monitoring device 30 can, for example, identify (or detect) whether one, two, or no sheets 3, 3b, 3c are located in the inlet area 16, or in particular, whether a single-layer sheet 36 or a double-layer sheet 37 is located in the inlet area 16. The number of identified sheets 3 (in particular, their temporal sequence) can be compared with a predetermined number of sheets 3 (or sheet sequence). In the event of a match, the sheet 3 can be delivered as sheet 3d to the further station 6, i.e., the discharge device remains inactive (in the first pivot position 23). In other cases, i.e., in the event of a mismatch (or in the event of a malfunction), the sheet 3 identified as defective can be discharged as sheet 3e (i.e., as waste). To this end, the sheet folding machine 1 includes a control device 40 connected to the monitoring device 30 so that it actuates (or pivots) the discharge device 20 as appropriate.

[0045] Figures 2a to 2c Shown respectively from Figure 1 Detailed view in the area of ​​the folding roller 11 and the folding bars 12, 13. Different states are shown in the detailed view.

[0046] Figure 2a A first state is shown in which neither of the two sheets 3b or 3c is dragged by the respective other sheet. The rear edge of the leading sheet 3b ("forerunner") is guided around one of the folding rollers 11 and then into the other folding fence 13. The front edge of the trailing sheet 3c ("follower") enters the inlet area 16 and thus into the folding fence 12. In this state, a defect-free folded product is produced. Here, the monitoring device 30 monitors the inlet area 16 of the folding fence 12 (or the sheet 3 in the plane 35). The monitoring device 30 recognizes the defect-free production of the folded product, and therefore the waste sheet discharge device is not activated; whereas in the two following attachments Figure 2b and 2c It’s different in China.

[0047] Figure 2b The second state is shown, in which the leading edge of the succeeding sheet 3c is dragged toward the exit by the trailing edge of the preceding sheet 3b. Consequently, the succeeding sheet 3c does not enter the inlet area 16 (or the folding barrier 12) as intended. In this state, a folding error occurs. The monitoring device 30 again monitors the inlet area 16 and detects defective production of the folded product. Therefore, in this state, the waste sheet discharge device is activated.

[0048] Figure 2cThe third state is shown, in which the trailing edge of the preceding sheet 3b is dragged toward the inlet by the leading edge of the succeeding sheet 3c. Consequently, the preceding sheet 3b does not enter the further folding barrier 13 as intended. In this state, incorrect folding also occurs. The monitoring device 30 again monitors the inlet area 16 and detects defective production of the folded product. Therefore, in this state, the waste sheet ejector is also activated.

[0049] In each of these three states, the monitoring device 30 preferably detects whether a single sheet, two sheets, or no sheet is located in the inlet area 16, particularly preferably by using an ultrasonic sensor 31 having a transmitter 32 and a receiver 33. The number of sheets detected in the inlet area 16 can be compared as an actual value with a setpoint value. The setpoint value can be predetermined as a sequence of changing values ​​(number of sheets or single-layer 36 or double-layer 37 sheets) depending on the ongoing folding production process.

[0050] "Drag" can occur for the following reasons: During the folding operation, the forerunner 3b is ejected from the folding barrier 12 after a successful fold. Simultaneously, the follower 3c enters the folding barrier 12. The leading edge of the follower 3c strikes the surface of the forerunner 3b. In the folding barrier's entry area 16, the two opposing sheets 3b and 3c collide and rub against each other along a specific path. During this contact, errors can occur, such as the follower 3c being pulled out of the folding barrier 12 and carried away by the forerunner, for example due to excessive friction or damage to the paper.

[0051] Reference Signs List

[0052] 1-sheet folding machine

[0053] 2-sheet feeder

[0054] 3 pages

[0055] Pages 3a-e

[0056] 4 Scale Flow

[0057] 5 First Folding Station

[0058] 6 Additional stations, in particular the second folding station

[0059] 7 Conveyor device, especially conveyor platform

[0060] 8 conveyor rollers

[0061] 9. Clamping device

[0062] 10 Mounting position for folding fence or sheet switch

[0063] 11 Folding rollers

[0064] 12 Folding Fence

[0065] 13 Additional folding fences

[0066] 14 Folding stop

[0067] 15 entrance lip

[0068] 16 Entrance Area

[0069] 17 Sheet switch (Bogenweiche)

[0070] 18 Length of folding fence

[0071] 20 Discharge device

[0072] 21 Discharge valve

[0073] 22 horizontal axis

[0074] 23 First swing position

[0075] 24 Second swing position

[0076] 25 First Surface

[0077] 26 Second Surface

[0078] 27 Discharge element

[0079] 28 Waste Pages

[0080] 29 discharge roller

[0081] 30 Monitoring device

[0082] 31 Ultrasonic Sensor

[0083] 32 Launcher

[0084] 33 Receiver

[0085] 34 Reflected light sensor

[0086] 35 pages of graphic design

[0087] 36 single-layer sheets

[0088] 37 double-layered pages

[0089] 40 Control Device

Claims

1. A sheet folding machine having a waste sheet discharge device, the sheet folding machine comprising: a sheet feeder (2) which generates a stream (4) of sheets (3), a first folding station (5) and a further station (6), wherein the first folding station comprises at least one folding fence (12) and at least two folding rollers (11) for folding the sheets (3), and A monitoring device (30), a control device (40) and a discharge device (20), wherein the monitoring device (30) monitors the flow (4) for errors and the control device (40) activates the discharge device (20) for discharging waste sheets (28) when an error is detected. It is characterized by: The monitoring device (30) is arranged at an inlet area (16) of the folding fence (12) and monitors the flow (4) in the folding fence (12), wherein the inlet area of ​​the folding fence is a front open area of ​​the folding fence, which is facing the folding rollers and at which sheets can enter the folding fence in the inlet direction, and The discharge device (20) is arranged downstream of the first folding station (5) and upstream of the further station (6).

2. The sheet folding machine according to claim 1, It is characterized by: The folding fence (12) includes an inlet lip, and The inlet region (16) is positioned adjacent the inlet lip.

3. The sheet folding machine according to claim 2, It is characterized by: The inlet lip is positioned close to the two folding rollers (11).

4. The sheet folding machine according to claim 1, It is characterized by: The monitoring device (30) includes an ultrasonic sensor (31).

5. The sheet folding machine according to claim 4, It is characterized by: During monitoring, the ultrasonic sensor (31) detects whether one, two or no sheets (3) are located in the folding barrier (12).

6. The sheet folding machine according to claim 4 or 5, It is characterized by: The ultrasonic sensor (31) detects in the flow (4) whether single-layer sheets and double-layer sheets (3) occur continuously and alternately.

7. The sheet folding machine according to claim 6, It is characterized by: The ultrasonic sensor (31) detects in the flow (4) whether a further double-layered sheet (3) occurs after a double-layered sheet within a predetermined time period.

8. A sheet folding machine according to any one of the preceding claims, It is characterized by: The monitoring device (30) monitors the flow (4) in the folding fence (12) for at least one of the following errors: a subsequent sheet (3, 3c) dragged by a preceding sheet (3, 3b), a preceding sheet (3, 3b) dragged by a subsequent sheet (3, 3c), and / or an incorrectly folded sheet.

9. A sheet folding machine according to any one of the preceding claims, It is characterized by: The discharge device (20) is arranged on the conveying device (7) between the first folding station (5) and the further station (6).

10. The sheet folding machine according to claim 9, It is characterized in that The discharge device (20) is designed as a switchable discharge flap (21).

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