Feed table for connecting a printing device to a folding machine

Abstract

A feed table (2) for connecting a printing device (1) to a folding machine (3) with two guides (10, 17) between which a pivotable loop flap (13, 15) is arranged, below which a paper loop (28) can be formed, with transport rollers (12, 21) assigned to the guides (10, 17), each of which is provided with a transport roller drive (22, 25), with a measuring section for determining the remaining length of the document (26), and with a control device for the transport roller drives (22, 25) is to be further developed in such a way that it is on the one hand more cost-effective and can be built shorter, and on the other hand compensates for the speed difference between the folding machine and the printing device in a simpler way.It is proposed that, as part of the measuring section, the printing device (1) for transmitting the remaining length of the document (26) is connected to the control device and / or folding machine (3) by means of a communication interface, that the measuring section further includes a sensor (23) that is able to detect the paper end (27) of a document (26) supplied by the printing device (1) and to report to the control device that the remaining length of the document can be determined via the control device, and that a suitable folding scheme for folding the determined remaining length can be selected by means of the control device.

Description

[0001] The invention relates to a feed table for connecting a printing device to a folding machine for transporting a document and for compensating for the different speeds between the folding machine and the printing device, with two guides between which a pivotable loop flap is arranged, below which a paper loop can form, with transport rollers associated with the guides, each of which is provided with a transport roller drive, with a measuring section for determining the remaining length of the document, and with a control device for the transport roller drives.

[0002] It is common practice to use large-format documents, especially printed paper rolls, for example by industry and reprographic service providers, to record technical documentation or other extensive data sets. The standard width of such paper rolls is up to 914 millimeters (36"). The total length of the paper roll—and thus the documents—can vary and, depending on the application, can reach 100 meters or more.

[0003] It is also common practice to fold such large-format documents for easier handling or archiving. The standardized folding of technical drawings is defined in DIN 824 for Germany. However, folding standards vary from country to country.

[0004] Such folding of large-format documents is usually carried out as automatically as possible, with folding machines being able to perform both longitudinal and transverse folding and operating, for example, according to the roller folding principle or the belt folding principle.

[0005] DE 10 2012 015 466 A1 already discloses a fully automatic folding machine, as shown below. Fig. Section 1 will be described in more detail below. This folding machine has a folding station with a large folding roller and two smaller folding rollers that work together with the large folding roller. Folding pockets are assigned to the folding rollers. The paper is fed to the folding rollers via infeed rollers.

[0006] In longitudinal folding, the large-format document, for example a printed paper web, is transported into the folding station and folded by repeatedly reversing the folding rollers, as shown below. Fig. 1 is described in more detail. If the document is only to be folded lengthwise, it is transported to the longitudinal folding tray and placed there after the folding process is complete.

[0007] From EP 1 302 326 A2, a paper transport device with a transition section, arranged between a plotter and a folding machine, is known. The size of the paper loop is controlled by sensors. Due to system limitations, the plotter's paper output is discontinuous, while the folding machine requires a continuous paper feed. To compensate for the different operating speeds, a loop flap is provided in the inlet area of ​​the transition section to form the loop. The paper loop is formed by a control device that holds the paper sheet in place. The size of the paper loop is monitored by the sensors, ensuring that the operation of the folding machine is not disrupted by jerky paper feeds, as the transport rollers associated with the folding machine can run continuously.

[0008] It is also known to feed paper to a folding machine downstream of a printing device via a feed table in which a measuring section is integrated to determine the total length of the paper formats.

[0009] In the Fig. Figure 1 shows this known arrangement in which a printing or paper processing device, for example a printing device 1, plotter, copier or the like, is connected to a folding machine 3 for a large format paper web by means of a feed table 2, which folds the large format paper web supplied by the printing device 1 via the feed table 2, hereinafter referred to as document, into a stack and places it in a folding tray not shown.

[0010] The folding machine 3 has, after a feed 4, feed rollers 5 as transport rollers which grasp the document and feed it via a document guide 6 to a folding station with small folding rollers 7 and a large folding roller 8, in which the document is folded in a manner known, for example, from DE 10 2012 015 466 A1 by reversing the folding rollers 7 and 8 several times.

[0011] The document is conveyed from the printing device 1 to the feed table 2 in the transport direction 9. The feed table 2 has a first guide 10, which is covered by a front cover 11 and in the gap of which front transport rollers 12 are arranged, which grip the document delivered from the printing device 1.

[0012] Viewed in the transport direction 9, a loop flap 13 is arranged behind the first guide 10. This flap can be pivoted from its closed position (shown) by a pivot direction 14 into the open loop flap 15 (shown with dashed lines), as will be explained below. Opposite the loop flap 13, a sensor 16 is arranged under the front cover 11.

[0013] Following the loop flap 13 in the transport direction 9 is a second guide 17 with a measuring section 18 for determining the paper length. The second guide 17 is covered by a rear cover 19. Middle transport rollers 20 and rear transport rollers 21 advance the document to the feeder 4 of the folding machine 3.

[0014] The complete measuring section 18 for determining the paper length, which is usually located behind the loop flap 13 when viewed in the transport direction 9, consists, for example, of three sensors arranged one behind the other. These sensors are approximately 150 mm apart. This allows the format length of a document to be determined so precisely that the folding machine 3 achieves a sufficiently accurate folding result. This measuring method does not require communication between the printing device 1 and the folding machine 3, and such communication is generally not necessary.

[0015] The loop flap 13 is necessary for speed compensation between the printing device 1 and the folding machine 3. The printing device 1, for example an LED printer, operates at a constant speed. The folding machine 3, however, decelerates and accelerates, thus having a variable speed. The folding machine 3 must not pull on the document supplied by the printing device 1, as this would impair the print quality. Therefore, a paper loop (not shown) is formed downwards in this area of ​​the open loop flap 15, in which a certain amount of excess paper is accumulated.

[0016] The formation of the paper loop is controlled by a sensor 16. If the document covers the sensor 16, the folding machine 3 assumes the speed of the output device. If, however, the sensor 16 is unobstructed, i.e., a paper loop has formed in the document web so that the document cannot cover the sensor 16, the speed of the folding machine 3 is increased until the sensor 16 is covered again.

[0017] EP 825 142 A2 already discloses a method and a device for buffering material webs to compensate for different processing speeds of upstream and downstream processing machines. Both processing machines and the buffer are integrated into a network through which information about the length of the processed material web and the next material web to be processed is exchanged. The total length of the material webs is calculated. However, EP 825 142 A2 does not disclose a method for determining the remaining lengths of the material webs, nor does it provide a measuring section for determining these remaining lengths.

[0018] The invention is based on the objective of further developing a feed table of the type mentioned above in such a way that it is, on the one hand, more cost-effective and can be built shorter, and on the other hand, compensates for the speed difference between the folding machine and the printing device in a simpler way.

[0019] The problem is solved according to the invention for a feed table of the type mentioned at the outset by the features specified in claim 1. Advantageous embodiments are specified in the dependent claims.

[0020] The object of the invention is achieved in that, as part of the measuring section, the printing device for transmitting the remaining length of the document is connected to the control device and / or folding machine by means of a communication interface, that the measuring section further comprises a sensor that is able to detect the paper end of a document supplied by the printing device and to report to the control device that the remaining length of the document can be determined via the control device, and that a suitable folding scheme for folding the determined remaining length can be selected by means of the control device.

[0021] This results in the feed table according to the invention requiring a significantly shorter measuring distance than with conventional connection of a printing device to a folding machine, and is therefore approximately 1 m shorter, resulting in a cost saving of approximately 30%.

[0022] The fact that only two transport rollers are provided, whose transport roller drives can be controlled separately at different speeds, results in simplifications in terms of both the plant design and the control system, and thus lower costs.

[0023] It has proven advantageous to control the size of the paper loop by controlling the speeds of the two transport roller drives differently, for example when the control device optimizes the size of the paper loop (28) with regard to jerky paper feed and / or discharge and / or transport problems.

[0024] According to the invention, the control device is designed such that the paper loop is formed during the printing process and that, upon completion of the printing process, a signal indicating the end of the sheet is transmitted from the printing device to the control device, on the basis of which the first transport roller drive is stopped to dismantle the paper loop, and that after dismantling the paper loop, the sensor transmits a signal indicating the end of the paper to the control device, which selects the appropriate folding scheme and sends it to the folding machine.

[0025] However, it is also possible to place a second sensor upstream of the first sensor, which initially signals the edge of the blade, thereby stopping the first transport roller drive. The distance between the two sensors only needs to be such that the first transport roller drive can be stopped before the edge of the blade reaches the (first) sensor.

[0026] According to the invention, the loop flap can be arranged centrally between two transport rollers.

[0027] Advantageously, the loop flap can be designed in such a way that documents that cannot be folded can be guided through the loop flap.

[0028] It has proven advantageous if the size of the paper loop is controlled by a calculation algorithm provided in the control device, taking into account the revolutions or step frequencies of the independently controlled transport roller drives (22, 25).

[0029] This allows loop formation to be controlled cost-effectively without the need for extensive additional sensors.

[0030] According to the invention, the control device is arranged in the feed table or in the folding machine.

[0031] The invention is explained in more detail below with reference to exemplary embodiments shown in the drawing. The drawing shows: Fig. 1 a known arrangement with a feed table for connecting a printing device to a folding machine, Fig. 2 a feed table shortened according to the invention with closed integrated loop flap and reduced measuring technology for residual length measurement, Fig. 3 the feed table according to the invention Fig. 2. With the loop flap open, operation with loop formation is possible.

[0032] In the Fig. Figure 2 shows a shortened feed table 2 according to the invention, with a closed integrated loop flap 13 and reduced measuring technology for residual length measurement. In the transport direction 9 of a document, viewed from the printing device 1 (not shown), a sensor 23 for the paper end of a document is mounted on the first guide 10 in front of the front transport rollers 12 (pair of transport rollers) with their first transport roller drive 22. Behind the first guide 10, the loop flap 13 with its loop flap drive 24 is arranged. A short second guide 17 with the rear transport rollers 21 and a second transport roller drive 25 follows this.

[0033] The Fig. Figure 3 shows the shortened feed table 2 according to Fig. 2 with the loop flap 15 opened by the loop flap drive 24. In this case, a document 26 was supplied by the printing device 1, the paper end 27 of which is located in the feed area of ​​the feed table 2. In the output area of ​​the feed table 2, the document 26 is delivered to the folding machine 3.

[0034] By controlling the speeds of the two transport roller drives 22 and 25 differently, a paper loop 28 is formed, which can assume different sizes, as indicated by the numerous paper loops 28 shown. In reality, however, only a single paper loop 28 is present.

[0035] Furthermore, a communication interface (not shown) is provided, which transmits the total length of the current document 26 from the printing device 1 to a control device (also not shown) assigned to the feed table 2 and to the folding machine 3.

[0036] This control device is designed to compensate for the speed difference between the printing device 1 and the folding machine 3 during the transfer of the document 26 from the printing device 1 to the folding machine 3. For this purpose, a paper loop 28 is formed. This loop is determined and optimized by the control device using a computational algorithm. The control device can be located in the feed table 2 itself or in the folding machine 3.

[0037] The paper length between the two transport rollers 12 and 21 is known because they are arranged in front of and behind the loop flap 13 and 15, respectively. These transport rollers are driven by independent drives 22 and 25, and their revolutions or step frequencies are known. Therefore, the known length of the paper loop 28 can be varied by changing the rotational speeds of the transport rollers 12 and 21. This allows the folding machine 3 to be slowed down so that a sufficiently large paper loop 28 is formed, ensuring that it never pulls on the part of the document 26 still in the printing device 1. The transport roller drives 22 and 25 drive the transport rollers 12 and 21 at partially different rotational speeds, so that the paper loop 28 can be formed or disassembled as required.

[0038] When the paper end 27 of document 26 leaves the printing device 1, a signal is transmitted from the printing device 1 to the folding machine 3 or the control device. The first transport roller drive 22 is then stopped, causing document 26 to halt at this point. The other end of document 26 remains inside the folding machine 3 and continues to be processed.

[0039] During this process, the paper loop 28 degrades until it is no longer present, as indicated by arrow 29 in connection with the in Fig. The process is illustrated by the paper loops 28 shown in Figure 3. Once the paper loop 28 has been completely removed, so that the document 26 is taut, the folding machine 3 pulls the document 26 out of the transport rollers 12 located in front of the loop flap 15, or the transport rollers are driven at the same speed as the transport rollers 21. During this process, the edge of the paper end 27 passes the sensor 23 and is detected. This detection signal is transmitted to the control device connected to the sensor 23, i.e., to the folding machine 3. The remaining length of the document 26 is now known to the control device and the folding machine 3 from the known dimensions of the feed table, allowing the control device to select a suitable folding pattern for this remaining length. During the remaining transport of the document, the transport roller drives 22 and 25 operate at the same speed.

[0040] Plans or documents 26 that should not be folded can also be ejected via the open loop flap 15.

[0041] The present patent application describes a feed table according to the invention with a loop flap integrated centrally between two transport rollers 12 and 21 and residual length measurement with reduced measuring technology.

[0042] In contrast to known feed tables 2, the shortened feed table 2 according to the invention does not require a complete measuring section for length determination; instead, only the remaining length of the document 26 is determined using a sensor 23. Additionally, the total length of the document 26 is transmitted from the printing device 1 to the folding machine 3 via a communication interface. However, since the length determination in the printing device 1 is prone to errors, and these errors would be directly visible in the folded document 26, an additional remaining length measurement in the feed table 2 is necessary.

[0043] This length measurement is performed as follows: The document 26 is fed from the printing device 1 via the feed table 2 into the folding machine 3. To compensate for the speed difference between the printing device 1 and the folding machine 3, a paper loop 28 is formed. The printing device 1 transmits the end of the sheet or paper 27, or the exit of the document 26 from the printing device 1, to the control device. The control device then stops the first transport roller drive 22. The document 26 stops at this point. The other end of the document 26 is in the folding machine 3 and continues to be processed. During this process, the paper loop 28 dissipates until it is no longer present (see Fig.3) If this is the case, the folding machine 3 pulls on the document 26 in the front transport rollers 12 in front of the loop flap 15 (first transport roller drive 22). At this moment, the paper of the document 26 is taut. Now the front transport rollers are driven at the same speed as the rear transport rollers. Subsequently, the edge of the paper end 27 passes over the sensor 23 and is detected and transmitted to the control unit of the folding machine 3. Now the remaining length of the document 26 is known and a suitable folding pattern for folding this remaining length can be selected by the control unit.

[0044] Unlike the known feed tables 2, the loop formation is not controlled by a loop switch, but rather determined by the control device using a computational algorithm. Since there are independent transport roller drives 22 and 25 in front of and behind the loop flap 13 and 15, respectively, and their rotational speeds and step frequencies are known, the paper length between the two transport rollers 12 and 21 is also known. Therefore, the size of the paper loop 28 is known, and the folding machine 3 can be slowed down so that a sufficiently large paper loop 28 is formed, ensuring that it never pulls on the part of the document 26 still in the printing unit 1. This prevents printing errors.

[0045] The size of the paper loop 28 can be kept as small as possible to avoid problems with paper transport, such as misalignment.

[0046] The loop flap 15, integrated in the middle between the two transport rollers 12 and 21, allows plans or documents that cannot be folded to be diverted.

[0047] To form a paper loop 28 optimized in size with regard to jerky paper feed and transport problems, the required arbitrary transport speeds of the transport rollers 12 and 21 with their different transport roller drives 22 and 25 can be achieved. Reference symbol list 1 Printing device 2 Feed table 3 folding machine 4 Feed 5 feed roller pairs 6 Document Management 7 small folding rollers 8 large folding roller 9. Transport direction 10 first tour 11 front cover 12 front transport rollers 13 Loop flap 14 Swivel direction 15 open loop flap 16 Sensor 17 second lead 18 measuring section 19 rear cover 20 medium transport rollers 21 rear transport rollers 22 first transport roller drive 23 Paper end sensor 24 loop flap drive 25 second transport roller drive 26 documents 27 Paper end 28 paper loops 29 Arrow

Claims

Feed table (2) for connecting a printing device (1) to a folding machine (3) for transporting a document (26) and for compensating for the different speeds between the folding machine (3) and the printing device (1), comprising two guides (10, 17) between which a pivotable loop flap (13, 15) is arranged, below which a paper loop (28) can form, with transport rollers (12, 21) assigned to the guides (10, 17), each of which is provided with a transport roller drive (22, 25), with a measuring section for determining the remaining length of the document (26), and with a control device for the transport roller drives (22, 25), characterized in that each guide (10, 17) is assigned only one pair of transport rollers (12, 21), whose transport roller drives (22, 25) can be controlled separately at different speeds.that as part of the measuring section, the printing device (1) is connected to the control device and / or folding machine (3) via a communication interface for transmitting the exit of the document end from the printing device (1), that the measuring section further comprises a sensor (23) which is able to detect the paper end (27) of a document (26) supplied by the printing device (1) and to report to the control device that the remaining length of the document can be determined via the control device, and that a suitable folding scheme for folding the determined remaining length can be selected via the control device. Feed table (2) according to claim 1, characterized in that the speeds of the two transport roller drives (22, 25) are controlled differently to control the size of the paper loop (28). Feed table (2) according to one of claims 1 to 2, characterized in that the control device optimizes the size of the paper loop (28) with regard to jerky paper feed and / or discharge and / or transport problems. Feed table (2) according to one of claims 1 to 3, characterized in that the control device is designed such that the paper loop (28) can be formed during the printing process, that at the end of the printing process a signal indicating the end of the sheet is transmitted from the printing device (1) to the control device, on the basis of which the first transport roller drive (22) is stopped to dismantle the paper loop (28), that after dismantling the paper loop (28) the sensor (23) transmits a signal indicating the end of the paper (27) to the control device, which selects the appropriate folding scheme and sends it to the folding machine (3). Feed table (2) according to one of claims 1 to 4, characterized in that the loop flap (13, 15) is integrated centrally between two transport rollers (12, 21). Feed table (2) according to one of claims 1 to 5, characterized in that the loop flap (13, 15) is designed such that documents (26) that are not to be folded can be directed out through the loop flap (13, 15). Feed table (2) according to one of claims 1 to 6, characterized in that the size of the paper loop (28) is controlled by a calculation algorithm provided in the control device, taking into account the revolutions or step frequencies of the independently controlled transport roller drives (22, 25). Feed table (2) according to one of claims 1 to 7, characterized in that the control device is arranged in the feed table (2). Feed table (2) according to one of claims 1 to 7, characterized in that the control device is arranged in the folding machine (3).

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