Interfacing between a continuous process and a discrete process in a bookbinding system

Abstract

A solution is proposed for controlling a bookbinding system (100) to make book blocks. A corresponding method (600) comprises setting (610) a binding speed of a binding station of signatures of the book blocks, each formed by one or more sheets in a corresponding forming station (121), so as to correspond to an operating speed of the bookbinding system (100) according to a maximum value of the numbers of the sheets of the signatures. A feeding speed of a feeding station (103) of the sheets of the book blocks is set (612-614) to a nominal value thereof, corresponding to the operating speed, reduced according to a ratio between a total number of the sheets and an ideal number of the sheets (equal to the number of the signatures multiplied by the maximum value of the numbers of the sheets of the signatures) of each book block. A computer program (500) for implementing the method (600) and a corresponding computer program product (145) are proposed. Moreover, a bookbinding system (100) for applying the method (600) and a bookbinding plant comprising such bookbinding system (100) are proposed.

Description

[0001] INTERFACING BETWEEN A CONTINUOUS PROCESS AND A DISCRETE PROCESS IN A BOOKBINDING SYSTEM

[0002] Technical field

[0003] The present invention relates to the bookbinding field. More specifically, this invention relates to the synchronization of different production processes.

[0004] Background

[0005] The background of the present invention is introduced hereinafter with the discussion of techniques relating to its context. However, even when this discussion refers to documents, acts, artifacts and the like, it does not suggest or represent that the discussed techniques are part of the prior art or are common general knowledge in the field relevant to the present invention. Particularly, it is expressly understood that possible drawbacks mentioned herein should not be considered to have been previously recognized in the prior art.

[0006] The production of books at industrial level involves the execution of several (production) processes in corresponding stations of a bookbinding plant. Some of these processes may be continuous, meaning that they process corresponding items of a same type continuously. A typical example is the feeding of (flat) sheets on which multiple book pages are printed. Other processes may instead be discrete, meaning that they collect corresponding items of a same type into groups and then process these groups of items continuously. A typical example is the formation of signatures from groups of sheets and then their binding (and particularly their sewing) into book blocks corresponding to the books to be produced.

[0007] Whenever a continuous process and a discrete process (relating to the same items) are performed in sequence, it is necessary that these processes are synchronized to ensure their correct operation. Particularly, this requires that the discrete process operates at a speed that corresponds to a speed of the continuous process taking into account the time required to collect the items in the corresponding groups. In the example at issue, the signatures are sewn at a speed that corresponds to the one with which the sheets are fed according to a number of the sheets of each signature.

[0008] However, in practice the groups of items may not be homogeneous; moreover, the feeding of the items may be subject to discarding thereof. Consequently, corresponding discontinuities are created in the synchronization between the continuous process and the discrete process. This is typical of the example at issue. In fact, the signatures of each book are hardly all formed by a same number of sheets (for example, both because a total number of the sheets may not be a multiple of the number of the signatures and because the sheets may be distributed in a non-uniform way to improve a quality of the book). Moreover, in the case of presence of service sheets (which are not part of the books to be produced), they are not fed from the feeding station to the sewing station.

[0009] The discontinuities between the (continuous / discrete) processes might be managed by interposing a buffer between them. The buffer accumulates the items provided by the continuous process for providing them to the discrete process when needed; this allows compensating for the discontinuities, within the limits of a capacity of the buffer. However, the interposition of the buffer is not always possible. Particularly, to be effective the buffer should have a relatively high capacity (to allow compensating for a corresponding number of discontinuities before saturating), with a consequent increase of its size. Moreover, the accumulation of the items in the buffer (received from the continuous process) and their subsequent extraction from the buffer individually (for feeding them to the discrete process) may be difficult. This is precisely the case of the example at issue. In fact, the buffer should accumulate the sheets (received from the feeding station) by stacking them into a hopper and subsequently extract them one by one from the hopper (for feeding them to the forming station). However, the extraction of the sheets from the hopper by separating them from the subsequent ones is relatively complex.

[0010] Another possibility for managing the discontinuities might be that of stopping the continuous process or slowing down the discrete process at the corresponding groups of items (for compensating for the missing items therein). However, also the stopping of the continuous process and the slowing down of the discrete process are not always possible. This is again the case of the example at issue. In fact, the sheets may be printed on a reel. An unwinding machine unwinds the reel and a cutting machine cuts the sheets from the (unwound) reel; a (combined) sewing machine forms the signatures and sews them. This process is typical in the production of books that have been printed (usually in relatively small batches) by means of digital printers. However, in general the unwinding machine does not tolerate impulsive stops and starts and the sewing machine does not tolerate too sudden and / or frequent decelerations / accelerations (especially when they operate at relatively high speeds).

[0011] Summary

[0012] The present invention is defined in the appended claims; particularly, one or more aspects of the present invention are defined in the independent claims and advantageous features thereof are defined in the dependent claims.

[0013] A simplified summary of the present invention is herein presented in order to provide a basic understanding thereof; however, the sole purpose of this summary is to introduce some concepts of the invention in a simplified form as a prelude to its following more detailed description, and it is not to be interpreted as an identification of its key elements nor as a delineation of its scope.

[0014] In general terms, the present invention is based on the idea of reducing a feeding speed for the same binding speed.

[0015] Particularly, an aspect provides a method for controlling a bookbinding system to make book blocks. The method comprises setting a binding speed of a binding station of signatures of the book blocks, each formed by one or more sheets in a corresponding forming station, so as to correspond to an operating speed of the bookbinding system according to a maximum value of the numbers of the sheets of the signatures. A feeding speed of a feeding station of the sheets of the book blocks is set to a nominal value thereof, corresponding to the operating speed, reduced according to a ratio between a total number of the sheets and an ideal number of the sheets (equal to the number of the signatures multiplied by the maximum value of the numbers of the sheets of the signatures) of each book block.

[0016] A further aspect provides a (software) computer program for implementing the method.

[0017] A further aspect provides a corresponding computer program product.

[0018] A further aspect provides a bookbinding system for applying the method.

[0019] A further aspect provides a bookbinding plant comprising such bookbinding system.

[0020] Brief description of the drawings

[0021] The solution of the present invention, as well as further features and the respective advantages, will be better understood with reference to the following detailed description thereof, provided purely by way of a non-restrictive indication, with its explanations that apply mutatis mutandis to every aspect thereof (irrespectively of the context in which they occur); the description is to be read in conjunction with the accompanying drawings (wherein, for the sake of simplicity, corresponding elements are denoted with equal or similar references and their explanation is not repeated, and the name of each entity is generally used to denote both its type and its attributes, like value, content and representation). In this respect, it is expressly understood that the drawings are not necessary drawn to scale (with some details that may be exaggerated and / or simplified) and that, unless otherwise indicated, they are merely used to illustrate the structures and procedures described herein conceptually. In addition, orientations and related position references (such as front, rear, upper, lower, lateral and so on) are to be understood in relation to a condition of use of the corresponding entities. Particularly:

[0022] FIG.1 shows a conceptual block diagram of a bookbinding system wherein the solution according to an embodiment of the present invention may be applied,

[0023] FIG.2 shows an example of operation of the bookbinding system in an ideal condition,

[0024] FIG.3 shows an example of operation of the bookbinding system according to an embodiment of the present invention,

[0025] FIG.4 shows a further example of operation of the bookbinding system according to an embodiment of the present invention,

[0026] FIG.5 shows the main software components that may be used to implement the solution according to an embodiment of the present invention, and

[0027] FIG.6A-FIG.6C show an activity diagram describing the flow of activities relating to an implementation of the solution according to an embodiment of the present invention.

[0028] Detailed description

[0029] With reference in particular to FIG. l, a conceptual block diagram is shown of a bookbinding system wherein the solution according to an embodiment of the present invention may be applied.

[0030] The bookbinding system 100 is used to make book blocks (not shown in the figure). In turn, the book blocks are used to produce corresponding books, for example, in a bookbinding plant of which the bookbinding system 100 is part (not shown in the figure). Each book block is formed by a block of (two or more) signatures that are bound together, for example, sewn. Each signature is formed by one or more sheets (typically of paper) that are folded to define different pages of the corresponding book.

[0031] The bookbinding system 100 comprises the following components.

[0032] A feeding station 103 feeds the sheets in succession. In a specific embodiment, in turn the feeding station 103 comprises the following components (hereinafter, reference will be made to this implementation of the feeding station 103, with similar considerations that apply to any other implementation thereof).

[0033] An unwinding station 106 unwinds a reel on which a plurality of sheets are printed, typically supplied by a digital printer (not shown in the figure). For example (not detailed in the figure), the unwinding station 106 is implemented by a corresponding machine, which comprises a shaft for mounting the reel and a motor that rotates it towards an output thereof. Particularly, the sheets of the reel comprise (book) sheets of one or more batches of books (equal to each other) of corresponding (production) jobs. Optionally, the sheets of the reel may also comprise one or more (service) sheets that are not part of the books. For example, the service sheets are quality control sheets, known as “System pages” or “Nozzle Failure Detection (NFD) pages”, which comprise a printing test that is used to verify a quality thereof by optical inspection. A control unit 109 (for example, a microcontroller) controls operation of the unwinding station 106.

[0034] A cutting station 112 cuts the sheets from the reel that has been unwound by the unwinding station 106. For example (not detailed in the figure), the cutting station 112 is implemented by a corresponding machine, which comprises a blade for cutting the sheets and a conveyor for conveying the (unwound) reel from the output of the unwinding station 106 through the blade and then the sheets to an output of the cutting station 112. Optionally, in case the reel may comprise service sheets, the cutting station 112 is also provided with a camera for identifying the service sheets and a diverter for discarding them. A control unit 115 (for example, a microcontroller) controls operation of the cutting station 112.

[0035] A separating station 118 transits the (book) sheets in succession that have been cut by the cutting station 112; the sheets are transited by introducing a distancing between each pair of consecutive sheets, so as to separate them for allowing their subsequent processing. For example (not detailed in the figure), the separating station 118 is implemented by a conveyor being faster than the one of the cutting station 112, so that each sheet received from the output of the cutting station 109 is accelerated and therefore spaced apart accordingly from the next one.

[0036] A forming station 121 forms the signatures from the corresponding sheets that are fed by the feeding station 103 (particularly, from the separating station 118 in the implementation at issue). For example (not detailed in the figure), the forming station 121 comprises a folding device that folds each sheet in half and a stacking device that stacks the folded sheets. A binding station, for example, a sewing station 124 (to which reference will be made in the following, with the same considerations that apply to any other implementation thereof) sews (or more generally binds) the signatures of each book block that have been formed by the forming station 121 to each other. The sewing station 124 therefore operates in discrete manner with respect to the continuous feeding of the sheets from the feeding station 103, due to the time required to form the signatures from the corresponding sheets in the forming station 121.

[0037] For example, the separating station 118, the forming station 121 and the sewing station 124 are part of a sewing machine 127 (to which reference will be made in the following, with the same considerations that apply to any other implementation thereof). A control unit 130 (for example, an industrial PC) controls operation of the sewing machine 127 (and hence of the separating station 118, the forming station 121 and the sewing station 124).

[0038] A control system controls operation of the whole bookbinding system 100. For example, such a control system is implemented by the control unit 130, which communicates directly / indirectly with the control units 115,109 for this purpose - such as with the control unit 130 communicating with the control unit 115 for controlling the cutting station 112, which control unit 115 in turn communicates with the control unit 109 for controlling the unwinding station 106 (to which reference will be made in the following, with the same considerations that apply to any other implementation thereof). For example, the control unit 130 comprises several units that are connected to each other via a bus structure 133. Particularly, a microprocessor (pP) 136, or more, provides the logic capability of the control unit 130. A non-volatile memory (ROM) 139 stores basic code for a bootstrap of the control unit 130. A volatile memory (RAM) 142 is used as a working memory by the microprocessor 136. The control unit 130 is provided with a mass memory 145 for storing programs and data (for example, a solid state disk, SSD). In addition, the control unit 130 comprises several controllers for peripherals 148 thereof; for example, the peripherals 148 comprise corresponding controllers for the separating station 118, the forming station 121 and the sewing station 124, a communication port with the control unit 115, a control panel (for example, a touch screen) for displaying information and entering commands, a driver for reading / writing removable storage devices (such as of USB type) and / or a network adapter for connecting the control unit 130 to a telecommunications network.

[0039] In a specific implementation of the sewing station 124 (to which reference will be made in the following, with the same considerations that apply to any other implementation thereof) it comprises the following components. A fixed saddle 151 transports the signatures (received from the forming station 121) in succession to a functional unit that performs the actual sewing, z.e., a sewing unit 154. Particularly, the fixed saddle 151 comprises a saddle plate 157 (wedge-shaped, inverted V-like) for receiving the signatures being opened astride it. A plurality of pegs (partly protruding through a longitudinal slot of the saddle plate at a vertex thereof) push the signatures along the saddle plate 157; particularly, four pegs 160a, 106b, 160c and 160d are visible in the figure. A closed-loop moving system 163 (for example, a chain) moves the pegs 160a-160d continuously along the saddle plate 157; the pegs 160a-160d are equidistant from each other along the moving system 163, with a pitch between each pair of consecutive pegs 160a-160d greater than a maximum value of a length of the sheets (and therefore of the signatures) along the saddle plate 157. The sewing unit 154 sews the signatures that have been pushed in succession towards it by the fixed saddle 151. For example, the sewing unit 154 comprises a movable saddle 166, which is opened (aligned with the fixed saddle 151) for receiving each signature and then is closed for bringing the signature under a sewing head 169 (which sews it with corresponding threads by means of a series of needles and crochets, not shown in the figure, starting a new book block if the signature is the first one thereof or adding the signature to a book block under formation otherwise).

[0040] In such case, the forming station 121 is configured to deposit each signature onto the movable saddle 151 (z.e., its saddle plate 157). In a specific implementation of the forming station 121, it has a twofold structure based on two support elements, for example, a pair of (opposed) upper cylinders 172 and a pair of (opposed) lower cylinders 175 (to which reference will be made in the following, with the same considerations that apply to any other implementation thereof). Normally, the upper cylinders 172 are closed (with a corresponding piston extended from a barrel of each of them) for supporting the sheets that are fed by the forming station 121 (with each sheet starting a new signature if the first one thereof or adding to a signature under formation otherwise). Once each signature has been completed, the upper cylinders 172 are opened (by retracting the pistons into the corresponding barrels), so that the signature falls by gravity onto the lower cylinders 175 which are closed (with a corresponding piston extracted from a barrel of each of them); the upper cylinders 172 are then closed again to repeat the same operations. Subsequently, the lower cylinders 175 are opened (by retracting the pistons into the corresponding barrels), so that the signature falls by gravity onto the fixed saddle 151; the lower cylinders 175 are then closed again to repeat the same operations. This twofold structure allows dividing the fall of each signature into two sections with reduced height; this introduces a certain parallelism between the formation of the signatures and their release, and it makes the operation more reliable.

[0041] With reference now to FIG.2, an example is shown of operation of the bookbinding system in an ideal condition.

[0042] Particularly, this occurs when the signatures of each book block are all made up of a same number of sheets. In this respect, in the following reference will be made to a simple example wherein each book block is made up of three signatures SI, S2 and S3, each of which is made up of four sheets, Fl l, F12, F13 and F14 for the signature SI, F21, F22, F23 and F24 for the signature S2, and F31, F32, F33 and F34 for the signature S3.

[0043] In general, the feeding station feeds the sheets (in continuous manner) at a feeding speed. The sewing station sews the signatures formed from the sheets (in a discrete manner) at a sewing speed. The forming station operates in synchrony with the feeding station (at the level of each sheet), and the sewing station operates in synchrony with the forming station (at the level of each signature), so as to define a corresponding operating speed of the bookbinding system for making the book blocks. Consequently, the sewing speed corresponds to the feeding speed, according to the (common) number of the sheets of each signature for allowing its formation.

[0044] More in detail, with reference to the specific implementation of the feeding station, a diagram 205 illustrates the operation of the unwinding station 106 and the cutting station 112 in the space domain. Particularly, the unwinding station 106 continuously unwinds the reel, denoted with the reference 210, thereby continuously providing the same to the cutting station 112 (leftwards in the figure). The cutting station 112 cuts the reel into the sheets Fi (with i=l 1-34) according to their length, and then provides them to the separating station 118 seamlessly (leftwards in the figure).

[0045] A diagram 215 illustrates the operation of the cutting station 112 in the time domain (t). The unwinding station 106 operates (z.e., unwinds the reel 215) at an unwinding speed corresponding to a book time Tb for making each book block. The cutting station 112 operates (z.e., provides the sheets Fi) at the same unwinding speed. Particularly, the diagram 215 indicates the instants ti (with i=l 1-34) at which the sheets Fi are provided from the cutting station 112 to the separating station 118. The instants ti are separated from each other by a (common) sheet time Th required to cut each sheet Fi.

[0046] A diagram 220 illustrates the operation of the separating station 118 in the space domain. Particularly, the separating station 118 continuously transits the sheets Fi (received from the cutting station 112) towards the forming station 121 (leftwards in the figure), separating them from each other by the (common) distancing D.

[0047] In the time domain, the separating station 118 operates in synchrony with the cutting station 112. Accordingly, the separating station 118 operates (z.e., transits the sheets Fi received from the cutting station 112) at a transiting speed higher than the unwinding speed, for allowing introducing the distancing D between the sheets Fi.

[0048] A diagram 225 illustrates the operation of the forming station 121 in the space domain. Particularly, the forming station 121 stacks the sheets Fi (received continuously from the feeding station 118) of each signature Sj (with j=1..3), and then provides the signatures Sj thus obtained continuously to the sewing station 124 (for graphic design purposes, the (folded) sheets in the signatures Sj are enlarged with respect to the representation of the (flat) sheets of above). A diagram 230 illustrates the operation of the forming station 121 in the time domain (t). The forming station 121 operates in synchrony with the separating station 118. Particularly, the diagram 230 indicates the (releasing) instants tj (withj=1..3) at which the signatures Sj are released from the forming station 121 to the sewing station 124. The releasing instants tj are separated from each other by a (common) signature time Ts required for forming each signature Sj.

[0049] With reference to the specific implementation of the sewing station 124, a diagram 235 illustrates the operation of its fixed saddle in the space domain. For this purpose, the diagram 235 indicates a (receiving) position of the pegs 160a-160d along the saddle plate 157 at the releasing instant tj at which each signature Sj is released from the forming station 121 onto the saddle plate 157, in a (fixed) releasing position Pr, for example, defined in relation to a leading edge thereof along a transport direction on the saddle plate 157. Particularly, at the releasing instant tl of the signature SI, a peg 160a is in a position Pal and a next peg 160b is in a position Pbl downstream and upstream, respectively, of the release position Pr along an advancement direction of the pegs 160a-160d along the saddle plate 157 (leftwards in the figure) defined by their moving system 163. Particularly, the position Pal of the downstream peg 160b follows the releasing position Pr by a (pre-defined) relatively small safety distance, so that an encumbrance of the signature SI on the saddle plate 157 at its releasing instant tl always falls within a free space between the pegs 160a- 160b even in the case of a maximum value of its length. In this way, the signature SI is released by the forming system 121 onto the saddle plate 157 without interfering with the pegs 160a-160b (to be pushed then along it by the upstream peg 160b). Subsequently, at the releasing instant t2 of the signature S2, the peg 160b is in a position Pb2 and a next peg 160c is in a position Pc2 downstream and upstream, respectively, of the releasing position Pr; likewise, at the releasing instant t3 of the signature S3, the peg 160c is in a position Pc3 and a next peg 160d is in a position Pd3 downstream and upstream, respectively, of the releasing position Pr. Since the sewing station 124 (and in particular the moving system 163 of the pegs 160a-160d) operates in synchrony with the forming station 121, the pegs 160a-160d corresponding to each signature Sj are in the same position when it is released onto the saddle plate 157 (i.e., Pal=Pb2=Pc3 and Pbl=Pc2=Pd3), so that the same situation repeats continuously. With reference now to FIG.3, an example is shown of operation of the bookbinding system according to an embodiment of the present invention.

[0050] A non-ideal condition is now considered wherein the signatures of each book block are formed by different numbers of sheets. In this respect, in the following reference will be made to a simple example wherein each book is formed by three signatures SI, S2 and S3, which are formed by four sheets, F11, F12, F13 and F 14 for the signature SI, three sheets F21, F22 and F23 for the signature S2, and four sheets F31, F32, F33 and F34 for the signature S3.

[0051] In general, the operating speed of the bookbinding system is defined, for example, by a nominal value of the feeding speed, as in the ideal condition (z.e., as if the signatures of each book block were all formed by the same maximum value of the numbers of the sheets). The sewing speed is set as in the ideal condition. Therefore, the sewing speed corresponds to the nominal value of the feeding speed according to the maximum value of the numbers of the sheets of the signatures. The (actual) feeding speed is instead reduced with respect to its nominal value according to the real situation. Particularly, the feeding speed corresponds to its nominal value reduced according to a ratio between a total number of the sheets and an ideal number of the sheets of each book block; the total number of the sheets corresponds to the real situation (equal to the sum of the numbers of the sheets of the signatures) and the ideal number corresponds to the ideal situation (equal to the number of the signatures multiplied by the maximum value of the numbers of the sheets of the signatures).

[0052] In this way, the excess time in making each book block, caused by the shortage of the sheets of the signatures with a number of the sheets lower than the maximum value, is distributed uniformly along it. Consequently, the forming station operates (slightly) out of phase with respect to the sewing station at the level of the signatures of each book block (but with them remaining in synchrony at the level of the book blocks). This phase shift is generally acceptable by the sewing station, thereby maintaining its operation unchanged (or at most requiring a few small modifications of the sewing speed as described below).

[0053] The above mentioned solution then allows making the book blocks even in this non-ideal condition, in general without requiring any interruption of the feeding station. This makes the operation of the bookbinding system more regular, with a positive effect on its yield.

[0054] Moreover, this solution is of general applicability; particularly, it is also suitable for the case wherein the feeding station (relatively common for the unwinding station) does not tolerate impulsive stops and restarts.

[0055] More in detail, with reference to the specific implementation of the feeding station, a diagram 305 illustrates the operation of the unwinding station 106 (which unwinds the reel 210) and the cutting station 112 (which cuts the sheets Fi, with i=l 1 - 34) in the space domain as above.

[0056] A diagram 315 illustrates the operation of the cutting station 112 in the time domain (t). A nominal value of the unwinding speed is defined corresponding to the operating speed of the bookbinding system for making the book blocks as in the ideal condition, so as to maintain the same book time Tb that would be obtained if the signatures of each book block were all formed by the same maximum value of the numbers of the sheets as above. The (actual) unwinding speed is instead reduced with respect to its nominal value according to the ratio between the total number of the sheets (11) and the ideal number of the sheets (12) of each book block. Particularly, the diagram 315 indicates the instants ti' (with i=l 1-34) at which the sheets Fi are provided from the cutting station 112 to the separating station 118. The instants ti' are separated from each other by a sheet time Th' which is increased accordingly, with respect to the one that would be obtained in the ideal condition (despite their sum being still equal to the same book time Tb).

[0057] A diagram 320 illustrates the operation of the separating station 118 in the space domain. The separating station 118 operates (in synchrony with the cutting station 112) at the same transiting speed corresponding to the nominal value of the unwinding speed. Therefore, the separating station 118 continuously feeds the sheets Fi (received from the cutting station 112) to the forming station 121, separating them from each other by a distancing D' that is increased accordingly with respect to the ideal condition.

[0058] A diagram 325 illustrates the operation of the forming station 121 (which forms the signatures Sj, with j=1..3) in the space domain as above.

[0059] A diagram 330 illustrates the operation of the forming station 121 in the time domain (t). As above, the diagram 330 indicates the releasing instants tj' (with j=1..3) at which the signatures Sj are released from the forming station 121 to the sewing station 124. In this case, due to the reduction of the feeding speed Fi of the sheets the releasing instants tj ' are out of phase with respect to the ideal situation. The releasing instants tj' are therefore separated from each other by different values of the signature time required to form each signature Sj with respect to the ideal situation (despite their sum being still equal to the same book time Tb). Particularly, the signature time is proportional to the number of the sheets Fi of each signature Sj, z.e., Tsl for the signature SI, Ts2 for the signature S2 and Ts3 for the signature S3. The operation of the forming station 121 is therefore out of phase (at the level of the signatures but not of the book blocks) with respect to the one of the sewing station 124. Nevertheless, provided that the sewing station 124 is capable of receiving all the signatures Sj at the corresponding releasing instants tj', this has no substantial impact on its operation.

[0060] With reference to the specific implementation of the sewing station 124, a diagram 335 illustrates the operation of its fixed saddle in the space domain. As above, the diagram 235 indicates the receiving position of the pegs 160a-160d along the saddle plate 157 (defined by their moving system 163) at the moment at which each signature Sj is released from the forming station 121 onto the saddle plate 157 in the releasing position Pr at the corresponding releasing instant tj'. Particularly, at the releasing instant tl ' of the signature SI a peg 160a is in a position Pal' and a next peg 160b is in a position Pbl' downstream and upstream, respectively, of the releasing position Pr, at the releasing instant t2' of the signature S2 the peg 160b is in a position Pb2' and a next peg 160c is in a position Pc2' downstream and upstream, respectively, of the releasing position Pr, and at the releasing instant t3 ' of the signature S3 the peg 160c is in a position Pc3' and a next peg 106d is in a position Pd3' downstream and upstream, respectively, of the releasing position Pr. In this case, due to the phase shift of the releasing instants tj', the pegs 160a-160d corresponding to each signature Sj are generally in different positions when it is released onto the saddle plate 157 (z.e., Pal'<>Pb2'<>Pc3' and Pbl'<>Pc2'<>Pd3'), but with the same situation repeating continuously for each book block. Therefore, provided that the (downstream) positions Pal' of the peg 160a, Pb2' of the peg 160b and Pc3' of the peg 160c still follow the releasing position Pr by a distance such that the (upstream) positions Pbl' of the peg 160b, Pc2' of the peg 160c and Pd3' of the peg 160d precede the encumbrance of each signature Sj on the saddle plate 157 given by its length, all the signatures Sj are still released by the forming system 121 onto the saddle plate 157 without interfering with the corresponding pegs 160a- 160b.

[0061] Referring now to FIG.4, a further example is shown of operation of the bookbinding system according to an embodiment of the present invention.

[0062] With reference to the specific implementation of the feeding station, a condition is now considered wherein the reel 210 comprises one or more service sheets. In this respect, reference will be made in the following to the ideal condition wherein the signatures of each book block are all formed by the same number of sheets (with the same considerations that apply to the case wherein the signatures of each book block are formed by a different number of sheets), and in particular to the same simple example of above (three signatures Sj each formed by four sheets Fi), wherein a service sheet Fs is present between the sheets F31 and F32 of a generic book block.

[0063] If the presence of the service sheets were known a priori, their discarding in the cutting station 112 might be compensated by applying the same technique as above (also taking into account the service sheets to define the maximum value of the numbers of the sheet of the signatures). However, in general the service sheets are identified only at the moment at which the reel is provided to the cutting station. In this case, the sewing speed is reduced when necessary. In fact, each (delayed) signature wherein one or more service sheets are present among its sheets is formed late in the forming station 118 (due to the time lost for the service sheets that have been discarded by the cutting station 112). The sewing speed is then reduced to recover the synchronism with the forming station 118, in particular, according to a ratio between the (actual) number of the sheets of the delayed signature and a (fictitious) number of the sheets of the delayed signature, equal to the actual number of the sheets plus the corresponding number of the service sheets.

[0064] More in detail, a diagram 405 illustrates the operation of the unwinding station 106 (which unwinds the reel 210) and the cutting station 112 (which cuts the sheets Fi, with i=l 1-34, and Fs) in the space domain as above.

[0065] A diagram 415 illustrates the operation of the cutting station 112 in the time domain (t). The sheets F11-F31 are provided from the cutting station 112 to the separating station 118 at the same instants tl l-t31 as above. An interval without any sheet (equal to the sheet time Th) is then introduced due to the lack of the service sheet Fs. Therefore, the (delayed) sheets F32, F33 and F34 are provided from the cutting station 112 to the separating station 118 at (delayed) instants t32A, t33Aand t34A, respectively, which are delayed by the sheet time Th with respect to their (original) values of above.

[0066] A diagram 420 illustrates the operation of the separating station 118 in the space domain. In this case, a gap without any sheet (equal to the length of the sheets plus the distancing D) is introduced due to the lack of the service sheet Fs (between the sheet F31 and the sheet F32).

[0067] A diagram 425 illustrates the operation of the forming station 121 (which forms the signatures Sj, with j=1..3) in the space domain as above.

[0068] A diagram 430 illustrates the operation of the forming station 121 in the time domain (t). The signatures S1-S2 are formed with the same signature time Ts and are then released from the forming station 121 to the sewing station 124 at the same releasing instants tl-t2 as above. Instead, the (delayed) signature S3 is completed late due to the service sheet being discarded; therefore, the formation of the signature S3 requires a (delayed) signature time TsAthat is increased by the sheet time Th with respect to its (original) value of above, and thus the signature S3 is released from the forming station 121 to the sewing station 124 at a (delayed) releasing instant t3Athat is delayed accordingly.

[0069] With reference to the specific implementation of the sewing station 124, a diagram 435 illustrates the operation of its fixed saddle in the space domain. As above, the diagram 435 indicates the receiving position of the pegs 160a-160d along the saddle plate 157 (defined by their moving system 163) at the moment at which each signature SI, S2 and S3 is released from the forming station 121 onto the saddle plate 157 in the releasing position Pr at the corresponding releasing instant tl, t2 and t3A, respectively. Particularly, at the releasing instants tl,t2 of the signatures S1,S2 the corresponding pegs 160a-160b,160b-160c are in the same positions Pal-Pbl,Pb2-Pc2 as above along the saddle plate 157. Instead, if the sewing station 124 operated at the same (original) sewing speed, at the releasing instant t3Aof the (delayed) signature S3, the corresponding pegs 160c and 160d (in dotted line in the figure) would be in positions Pc3Aand Pd3A, respectively, more advanced with respect to the (expected) ones Pc3 and Pd3, respectively, of above. The sewing speed is then reduced in correspondence to the signature S3 (z.e., between the releasing instant t2 of the previous signature S2 and the releasing instant t3Athereof); particularly, the operation of the sewing station 124 is slowed down so that when the signature S3 is released onto the saddle plate 157 the corresponding pegs 160c and 160d are again in the positions Pc3 and Pd3, respectively.

[0070] With reference now to FIG.5, the main software components are shown that may be used to implement the solution according to an embodiment of the present invention.

[0071] Particularly, all the software components (programs and data) are denoted as a whole with the reference 500. The software components are typically stored in the mass memory and loaded (at least partially) into the working memory of the control unit of the sewing station (or more generally of the control system of the bookbinding system) when the programs are running, in addition to an operating system and to various application programs not directly relevant to the solution of the present invention (and thus omitted in the figure for the sake of simplicity). The programs are initially installed into the mass memory, for example, from removable storage units or from a network. In this respect, each program may be a module, segment or portion of code, which comprises one or more executable instructions for implementing the specified logical function.

[0072] A sewing manager 505 manages (directly) the operation of the sewing machine and (indirectly) the operation of the cutting station (which in turn manages the operation of the unwinding station), and thus of the entire bookbinding system. The sewing manager 505 uses corresponding drives, as a whole denoted with the reference 510, for corresponding peripherals of the sewing machine (comprising the separating station, the forming station, the sewing station and the control panel). The sewing manager 505 uses a cutting interface 515 for communicating with the control unit of the cutting station. The sewing manager 505 reads / writes a configuration repository 520, which defines configuration information of the bookbinding system. As far as relevant for the purposes of the present description, the configuration repository 520 contains the following configuration information. The configuration information indicates an operating speed of the bookbinding system, such as in terms of a nominal value of the feeding speed of the sheets; for example, in the specific implementation of the feeding station, the configuration repository 520 contains the transiting speed of the sheets in the separating station and a nominal value of the distancing D introduced between the sheets by the separating station. The configuration information defines each job for producing corresponding batches of book blocks of the same type whose pages are printed on the reel. Particularly, the configuration repository 520 contains an indication of the number of the signatures, of the corresponding numbers of the sheets of the signatures and, in the specific implementation of the feeding station, the length of the sheets / signatures of each book block of the job (and optionally of a number of the books of the job). The sewing manager 505 uses a planner 525 for planning the operation of the bookbinding system. For this purpose, the planner 525 reads / writes a model repository 530. The model repository 530 defines an operating model of the bookbinding system at least for a current job. The operating model specifies the feeding speed (unwinding speed and transiting speed in the specific implementation of the feeding station) for the job and the sewing speed in correspondence to each signature of the job (for example, by means of a general value thereof and possible modified values for some signatures). In the specific (twofold-structure) implementation of the forming station, optionally the model also specifies a closing time of the lower cylinders (or more generally of the lower support) for each signature. The planner 525 uses a simulator 535 for calculating simulations of the operation of the bookbinding system. For this purpose, the simulator 535 reads the model repository 530. The sewing manager 505 reads the model repository 530 for controlling the operation of the bookbinding system accordingly.

[0073] With reference now to FIG.6A-FIG.6C, an activity diagram is shown describing the flow of activities relating to an implementation of the solution according to an embodiment of the present invention.

[0074] Particularly, the diagram represents an exemplary process that may be used to control the bookbinding system with a method 600. In this respect, each block may correspond to one or more executable instructions for implementing the specified logical function on the control unit of the sewing machine (or more generally on the control system of the bookbinding system).

[0075] The process begins at the start black circle 602 and then passes to block 604 when a (new) reel is loaded into the unwinding machine; for example, this occurs after the bookbinding system has been switched on or a previous reel has been replaced (such as after its end). In response thereto, the sewing manager receives an indication of an operating speed of the bookbinding system (saving it in the configuration repository if necessary), for example, via the drive of the control panel where it is entered manually by an operator of the bookbinding system. In the specific implementation of the feeding station, the operating speed may be defined by the transiting speed (selected by the operator, such as according to the type of paper of the reel) together with the nominal value of the distancing (retrieved from the configuration repository where it is pre-set to a minimum value). Typical values are 1- 3 m / s for the transiting speed and 50-70 mm for the nominal value of the distancing. The sewing manager at block 608 receives the configuration information of a (current) job to be executed (starting from the first one of the reel). The configuration information comprises the number of the signatures, the numbers of the sheets of the signatures and the length of the sheets of each book block, and optionally the number of the book blocks of the job (saving it in the configuration repository if necessary); for example, the configuration information is extracted from a descriptor of the jobs of the reel stored in a file that is provided to the control unit concurrently with the loading thereof (for example, from a removable storage device or the network). At the same time, the sewing manager also determines the maximum value of the numbers of the sheets of the signatures and the total number of sheets of the book block (as the sum of the number of the sheets of all the signatures). The information of above defines the book time required to make each book block. In fact, a corresponding nominal value of the sheet time (Th) is given by the time required to transit through the separating station a section equal to the length of the sheets (H) plus the nominal value of the distancing (D) at the transiting speed (Vt):

[0076] Th = — vt

[0077] Since the sewing station works as in an ideal condition (z.e., as if the signatures were all formed by the same maximum value of the numbers of the sheets), a corresponding nominal value of the signature time (Ts) is given by the nominal value of the sheet time Th multiplied by the maximum value of the numbers of the sheets of the signatures (MAXh):

[0078] The book time (Tb) for sewing the signatures of each book block is then equal to the nominal value of the signature time Ts multiplied by the number of the signatures (Ns):

[0079] Tb = Ns - Ts = Ns - MAXh ■ — vt

[0080] Continuing at block 610, the planner sets the sewing speed corresponding to the operating speed of the bookbinding system (saving it in a (new) model for the job in the corresponding repository). Particularly, in the specific implementation of the sewing station, the sewing speed defines both a transporting speed of the signatures along the fixed saddle (such as in m / s) and a processing speed of the signatures in the sewing unit (such as in signatures / min), which correspond to each other (z.e., with a transporting time in which each signature is transported along the fixed saddle equal to a processing time in which each signature is processed in the sewing unit, starting a new book block or sewing it to a book block under formation). Since the sewing station operates as in the ideal condition, the sewing speed (Vs) is equal to the inverse of the nominal value of the signature time Ts:

[0081] „ i vt

[0082] Vs = — = - .

[0083] Ts MAXhTH+D)

[0084] At this point, the planner sets the (actual) feeding speed. In the specific implementation of the feeding station, the sewing manager at block 612 calculates a nominal value of the unwinding speed corresponding to the ideal condition. The nominal value of the unwinding speed (Vu) is then given by the ratio between a section equal to the length of the sheets (H) that is unwound from the reel and the nominal value of the sheet time (Th):

[0085] The planner at block 614 sets the unwinding speed (saving it in the model for the job in the corresponding repository). Since in the book time Tb the unwinding station actually unwinds a section of the reel equal to the length of the sheets H multiplied by the total number of the sheets in the book block (TOTh), the unwinding speed (Vu1) is:

[0086] The (actual) sheet time is then increased accordingly. In fact, the sheet time (Th1) is given by the time required to unwind a section equal to the length of the sheets (H) from the reel at the unwinding speed Vu':

[0087] Likewise, the (actual) distancing is also increased accordingly. Since the unwinding station actually unwinds a section of the reel equal to the length of the sheets H in the same sheet time Th' in which the separating station transits the sheet of length H plus the distancing that is actually introduced (D1), we have that: H+D'H

[0088] The (actual) signature time (Tsj) of each j -th signature is now given by the product of the sheet time Th' and the number of the sheets of the signature (Nhj):

[0089] Tsj = Nhj ■ Th'.

[0090] The simulator at block 616 calculates a simulation of the operation of the bookbinding system. In the specific implementation of the sewing station, the simulation indicates the releasing instants of each signature of a generic book block onto the saddle plate (starting from a reference time); particularly, the releasing instant of each signature (tj ') is given by the releasing instant of the previous signature (tj-T) plus the corresponding signature time (Tj'): tj' = tj - 1' + Tj'.

[0091] Moreover, the simulation indicates the receiving position of each peg along the saddle plate at the releasing instant of each signature (starting from an initial condition wherein the receiving position of a generic peg follows the releasing position by the safety distance, for example, 10-20 mm); particularly, the receiving position of each k-th peg at each j-th releasing instant (Pk(j)) is given by its position at the previous releasing instant (Pk(j-1))) plus the product of the sewing speed Vs by the nominal value of the signature time Ts:

[0092] Pk(f) = Pk(j ~ l)e + Vs ■ Ts. At this point, the planner analyzes the simulation. For this purpose, a loop is started at block 618, wherein the planner take into account a (current) signature, starting from the first one in the book block. The planner at block 620 classifies the signature according to the capability of the sewing station to receive it from the forming station. In the specific implementation of the sewing station, it is capable of receiving the signature if the receiving position of no peg falls within an encumbrance of the signature on the saddle plate, between the releasing position and the releasing position minus the length of the signature; conversely, the sewing station is incapable of receiving the signature if the receiving position of a peg falls within the encumbrance of the signature, so that such (interfering) peg would interfere with the release of the signature onto the saddle plate. The flow of activity branches at block 622 according to the outcome of the classification of the signature. If the sewing station is incapable of receiving the signature, the planner at block 624 classifies the signature as impossible (for example, by asserting a corresponding impossibility flag in the simulation). Conversely, if the sewing station is capable of receiving the signature, the planner at block 626 classifies the signature as possible (for example, by deasserting the corresponding impossibility flag in the simulation, or by taking no action if all the impossibility flags are initialized by deasserting them). The flow of activity merges again at block 628 from block 624 or block 626. At this point, the planner verifies whether a last signature of the book block has been taken into account. If not, the process returns to block 618 to repeat the same operations for a next signature of the book block. Conversely, once all the signatures of the book block have been taken into account, the loop is ended by descending to block 630.

[0093] The flow of activity now branches according to a number of the impossible signatures (indicated by the impossibility flags that are asserted). If no signature is impossible, this means that the bookbinding system may operate correctly. As a further improvement, in this case the planner verifies whether the operating speed may be increased (with a corresponding increase of productivity of the bookbinding system). For this purpose, the planner at block 632 increases the operating speed (the transiting speed in this case) by a fixed amount, for example, 5-10%. The planner at block 634 sets the sewing speed, the nominal value of the unwinding speed and the (actual) unwinding speed accordingly as above. The simulator at block 636 calculates a (new) simulation of the operation of the bookbinding system thus modified. The planner at block 638 analyses the simulation as above for classifying the signatures of a generic book block as possible / impossible. The flow of activity branches at block 640 according to a number of the impossible signatures. If no signature is still impossible, the process returns to block 632 to verify whether the operating speed may be further increased. If instead one or more signatures have become impossible, or in any case once the transiting speed would exceed an admissible maximum value thereof, the planner at block 642 sets the model according to the last simulation wherein no signature is impossible (replacing it in the corresponding repository if necessary).

[0094] Referring again to block 630, if one or more signatures are impossible the bookbinding system would be in an error condition; for example, this may occur as the number of the signatures with the number of the sheets lower than its maximum value, the number of missing sheets in such signatures and / or the length of the sheets increase. In such case, the flow of activity branches at block 644 according to a comparison between a number of the impossible signatures and an error threshold; the error threshold (for example, 10-20% of the total number of the signatures in each book block) defines an admissible maximum frequency of the modifications of the sewing speed required to remove the error condition (as described below).

[0095] If the number of the impossible signatures is (possibly strictly) lower than the error threshold, the planner attempts to modify the sewing speed in correspondence to each impossible signature for removing the error condition. For this purpose, a loop is started at block 646 wherein the planner takes into account a (current) impossible signature, starting from the first one of the book block. The planner at block 648 calculates a delay of the sewing station that makes it capable of receiving the impossible signature. In the specific implementation of the sewing station, the delay is defined according to a difference between a (following) target position and the receiving position of the interfering peg (at the releasing instant of the impossible signature), either in spatial or temporal terms; the following target position is defined so as to follow the encumbrance of the impossible signature by a safety distance (for example, 10-20 mm). The planner at block 650 calculates an advance of the sewing station that makes it capable of receiving the impossible signature. In the specific implementation of the sewing station, the advance is defined according to a difference between the receiving position and a (preceding) target position of the interfering peg (at the releasing instant of the impossible signature), either in spatial or temporal terms; the preceding target position is defined so as to precede the encumbrance of the impossible signature by a (further) safety distance (for example, again 10-20 mm). The flow of activity branches at block 652 according to a comparison of the differences (delay and advance) of above with an admissible maximum difference; for example, the maximum difference is defined in terms of a corresponding variation of the sewing speed (as described below), z.e., by an admissible maximum variation of the sewing speed (for example, 3-8% of its original value).

[0096] If at least one difference is (possibly strictly) lower than the maximum difference, the planner at block 654 selects one of them. Particularly, if only one difference is lower than the maximum difference, the planner selects that difference (only admissible). If instead both differences are lower than the maximum difference, the planner selects one of them (both admissible) according to a corresponding selection policy; for example, the planner selects the modification that brings the peg corresponding to the impossible signature (z.e., the one that pushed a previous signature) downstream of the impossible signature (to avoid idle cycles in the sewing unit). The flow of activity branches at block 656 according to the selected difference. If the delay has been selected, the planner at block 658 increases the sewing speed in correspondence to the impossible signature according to the delay (in the model in the corresponding repository). Conversely, if the advance has been selected, the planner at block 660 reduces the sewing speed in correspondence to the impossible signature according to the advance (in the model in the corresponding repository). In both cases, the sewing speed is modified between the releasing instant of the signature preceding the impossible signature and the releasing instant of the impossible signature. A corresponding modification (increase or reduction) of the sewing speed is calculated so that the interfering peg is in the corresponding (following or preceding, respectively) target position at the releasing instant of the impossible signature. Particularly, disregarding for simplicity a time required to accelerate / decelerate the sewing station, this requires that the interfering peg moves at a (modified) sewing speed (VsA) such that it travels a distance corresponding to the target position (Pt), which differs from a distance corresponding to the receiving position (Pr) by a positive (given by the delay) or negative (given by the advance) value (A), in the same corresponding signature time Tsj wherein the interfering peg would have traveled the distance corresponding to the receiving position moving at the (original) sewing speed Vs:

[0097] Pt Pr

[0098] The process continues at block 662 from block 658 or block 660. At this point, the planner verifies whether a last impossible signature has been taken into account. If not, the process returns to block 646 to repeat the same operations for a next impossible signature.

[0099] Referring again to block 644, if the number of the impossible signatures is (possibly strictly) higher than the error threshold, as a further improvement the planner reduces the operating speed of the bookbinding system in an attempt to reduce the number of the impossible signatures. For example, in the specific implementation of the feeding station, the planner at block 664 verifies whether the nominal value of the distancing has reached a maximum value thereof (for example, 2-4 times its original value in the configuration repository). If not, the planner at block 666 increases the nominal value of the distancing (only for the job) by a fixed amount, for example, equal to 3-8%. The process then returns to block 610 to repeat the same operations as above. Therefore, the unwinding speed and the sewing speed are reduced, and thus the (actual) distancing, the sheet time, the signature times and the book time are increased accordingly. This limits an impact on the operation of the bookbinding system, as it nonetheless leaves the transiting speed of the sheets in the separating station unchanged. In this respect, it should be noted that the resulting slowdown of the bookbinding system does not necessarily lead to a loss of productivity, given that the operation of the bookbinding system is more regular thanks to the smaller number of impossible signatures that require a lower number of modifications of the sewing speed.

[0100] Referring again to block 652, if both the (delay and advance) differences between the receiving position and the corresponding target position of the interfering peg are (possibly strictly) higher than the maximum difference, also in this case as a further improvement the planner reduces the operating speed of the bookbinding system, in an attempt to no longer have differences higher than the maximum difference. For example, in the specific implementation of the feeding station, the planner at block 668 verifies whether the transporting speed has reached an admissible minimum value thereof (for example, 50-70% of its original value). If not, the planner at block 670 reduces the transporting speed by a predetermined amount, for example, equal to 1-3%. For this purpose, the sewing manager may issue a warning signal (for example, of acoustic type) and then display a message (on the control panel via its drive) wherein such reduction is suggested of the transiting speed (and then of the entire bookbinding system). Assuming that the operator accepts the reduction, the process then returns to block 616 to repeat the same operations as above. Therefore, the unwinding speed and the sewing speed are reduced, and then the sheet time, the signature times and the book time are increased accordingly. This slows down the whole bookbinding system, since the operating speed being set initially is not sustainable. In this case as well, the resulting slowdown of the bookbinding system does not necessarily result in a loss of productivity, since the bookbinding system operates more smoothly due to the smaller modifications of the sewing speed.

[0101] The process instead continues at block 672 from block 664 (if the nominal value of the distancing may not be increased because it has reached its maximum value) or from block 668 (if the transiting speed may not be reduced because it has reached its minimum value, or it has not been accepted by the operator). In both cases, it is not possible to guarantee a regular execution of the job (which may not even be possible at all). In this case, the sewing manager emits a warning signal (for example, an acoustic signal accompanied by an explanatory message on the control panel via its drive), while still attempting to execute the job. Optionally, the planner tries to find an alternative composition of each book block (in terms of number of the signatures and / or numbers of the sheets of the signatures) that may improve the execution of the job. For this purpose, the planner at block 672 selects an alternative composition of each book block, for example, among all the possible ones with a minimum / maximum number of sheets for each signature in increasing order of uniformity of the signatures. The simulator at block 674 calculates a simulation as above of the operation of the bookbinding system relative to this alternative composition. The planner at block 676 analyzes the simulation as above to verify whether the job (with the alternative composition) might be executed regularly, z.e., without impossible signatures or at least with admissible modifications of the operation of the bookbinding system. The flow of activity branches at block 678 according to an outcome of this verification. If the job might still not be executed regularly, the process returns to block 672 to repeat the same operations with a next alternative composition. Conversely, if the job might now be executed regularly, the sewing manager outputs an indication of this alternative composition (for example, by displaying it on the control panel via its drive).

[0102] The process then continues at block 682 from block 642, from block 662 (when the error condition has been removed with no more impossible signatures) or from block 680. At this point, the planner optionally sets the closing time of the lower cylinders of the forming station for each signature. Normally, the opening and closing times of the (upper and lower) cylinders are set to nominal values that are pre-defined so as to ensure the correct operation of the forming station even in the worst case condition (z.e., to allow each newly formed signature to fall by gravity from the upper cylinders onto the lower cylinders and from the lower cylinders onto the saddle plate according to the different weights and sizes that are possible). However, as the number of the sheets in the signature decreases, the signature time for its formation (on the upper cylinder) reduces accordingly. Therefore, as a further improvement the closing time of the lower cylinders (which have opened to release a previous signature onto the saddle plate) is reduced in the same way to ensure that they are closed and thus are capable of receiving the signature when the upper cylinders are opened (after the signature time). Particularly, since the signature time Tsj of the j -th signature is equal to the nominal value of the signature time Ts reduced according to the ratio between the number of the sheets of the signature Nj and the maximum value of the sheets of the signature MAXh, the closing time (Tcj) for the j -th signature is reduced in the same way with respect to its nominal value (Tc): , ewing manager at block 684 controls the bookbinding system for executing the job according to its model (retrieved from the corresponding repository), initializing it if necessary to bring all its stations into synchronization. Particularly, the sewing manager controls the cutting station (via the corresponding interface) for controlling the unwinding station to unwind the reel at the unwinding speed and to cut the reel according to the length of the sheets, the separating station (via the corresponding drive) for transporting the sheets at the transiting speed, and the sewing station (via the corresponding drive) for sewing the signatures at the sewing speed (in this case, the fixed saddle for transporting the signatures and the sewing unit for processing the signatures) as indicated in the model (retrieved from the corresponding repository).

[0103] The flow of activity then branches at block 686. In case the reel might also comprise service sheets, each time the cutting station identifies a service sheet (and discards it), the sewing manager receives a corresponding notification. Therefore, if the sewing manager has received the notification of a (new) service sheet, the planner modifies the operation of the sewing station in correspondence to the (delayed) signature, among the sheets of which the service sheet is present, to compensate for the discarding of the service sheet by the cutting station. For this purpose, the planner at block 688 calculates a reduced value of the sewing speed. Disregarding for simplicity a time required to accelerate / decelerate the sewing station, the sewing station operating at the reduced value of the sewing speed (VsA) should perform the same operations in a (delayed) signature time (TsjA), given by the corresponding signature time Tsj plus the sheet time Th', that it would have performed operating at the previous value of the sewing speed, possibly already modified as above (and then generally indicated with Vs') in the signature time Tsj, so that: from which it is obtained:

[0104] The flow of activity branches at block 690 according to a comparison between a corresponding (total) reduction in the sewing speed, given by the reduced value thus obtained minus its original value (before the possible modification of above), and the admissible maximum difference. If the total reduction is (possibly strictly) lower than the maximum difference, the planner at block 692 modifies the sewing speed accordingly (in the model in the corresponding repository) in correspondence to the delayed signature (ie., between the releasing instant of a signature preceding the delayed signature and the releasing instant of the delayed signature). Conversely, if the total reduction is (possibly strictly) higher than the maximum difference, the planner at block 694 sets a stop of the sewing station in correspondence to the delayed signature that compensates for the discarding of the service sheet. Particularly, this requires a stop time corresponding to the sheet time (taking into account a deceleration and acceleration time to stop and restart, respectively, the sewing station). As above, the sewing manager schedules such a stop of the sewing station in correspondence to the next formation of the delayed signature. The process continues to block 696 from block 692 or from block 694. The same point is also reached directly from block 686 if the sewing manager has not received the notification of any new service sheets (always in case the reel may not comprise service sheets). At this point, the sewing manager verifies whether the job has been completed (for example, once its number of book blocks has been reached). If not, the process returns to block 682 to repeat the same operations continuously.

[0105] Conversely, once the job has been completed, the process continues to block 698. At this point, the sewing manager verifies whether the reel is ended with all its jobs that have been processed. If not, the flow of activity returns to block 606 to repeat the same operations for a next job of the reel. In general, this may involve a modification of the operation of the bookbinding system (unwinding speed, transiting speed, sewing speed). Such a modification of the operation of the bookbinding system (only at the job change) is generally acceptable. Otherwise, the sewing manager stops and then restarts the bookbinding system (with the consequent loss of time that is negligible considering its very low frequency). Conversely, once the reel is finished, the process ends at the final black and white concentric circles 699.

[0106] Modifications

[0107] In order to satisfy local and specific requirements, a person skilled in the art may apply many logical and / or physical modifications to the present invention, provided that it remains within the scope of the claims. Particularly, the present invention may be practiced even without the specific details (such as the numerical values) set forth in the preceding description to provide a more thorough understanding thereof; conversely, well-known features may have been omitted or simplified in order not to obscure the description with unnecessary particulars. Specific features described in connection with any embodiment of the present disclosure may be incorporated in any other embodiment as a matter of general design choice. Moreover, items presented in a same group and different embodiments, examples or alternatives are not to be construed as de facto equivalent to each other (but they are separate and autonomous entities). In any case, each numerical value should be read as modified according to the applicable tolerances; particularly, unless otherwise indicated, the terms “substantially”, “about”, “approximately” and the like should be intended as within 10%, preferably 5% and still more preferably 1%. Moreover, each range of numerical values should be intended as expressly specifying any possible number along the continuum within the range (comprising its end points). Ordinal or other qualifiers are merely used as labels to distinguish elements with the same name but do not by themselves connote any priority, precedence or order. The terms include, comprise, have, contain, involve and the like should be intended with an open, non-exhaustive meaning (z.e., not limited to the recited items), the terms based on, dependent on, in agreement with, according to, function of and the like should be intended as a non-exclusive relationship (z.e., with possible further variables involved), the term a / an should be intended as one or more items (unless expressly indicated otherwise), and the term means for (or similar functional formulation) should be intended as any structure adapted or configured for carrying out the relevant function.

[0108] More specifically, each of the following modifications may be applied (alone or in combination with any other modification) to the corresponding features mentioned above (wherein the features described in each complete sentence may be implemented independently of the features described in the other sentences, except for those strictly necessary functionally). Particularly, it is expressly understood that each feature mentioned above may be replaced by any of its alternatives or it may be generalized to the corresponding genus as set out in the following.

[0109] For example, an embodiment provides a method for controlling a bookbinding system to make book blocks. However, the bookbinding system may be of any type (for example, formed by multiple separated machines each comprising any one or more of its stations, a single machine, and so on) for making book blocks of any type (for example, of one or more jobs, and so on).

[0110] In an embodiment, each book block comprises a plurality of signatures each comprising one or more book sheets. However, the book block, the signatures and the book sheets may be of any type (for example, with each book block comprising any number of signatures, each signature comprising any number of book sheets, each book sheet comprising any number of pages, and so on).

[0111] In an embodiment, the bookbinding system comprises a feeding station for feeding the book sheets in succession. However, the feeding station may be of any type (for example, formed by an unwinding station, a cutting station and a separating station, a hopper for loading a stack of sheets and a station for extracting the sheets from the hopper, and so on) for feeding the book sheets in any way (for example, separated from each other, seamlessly, and so on).

[0112] In an embodiment, the bookbinding system comprises a forming station for forming the signatures from the corresponding book sheets being fed by the feeding station. However, the forming station may be of any type (for example, for forming each signature, providing it to an intermediate element and then to the binding station, for forming each signature and providing it directly to the binding station, for folding each book sheet and then stacking the folded book sheets, for stacking the book sheets and then folding the stacked book sheets, and so on).

[0113] In an embodiment, the bookbinding system comprises a binding station for binding the signatures of each book block being formed by the forming station to each other. However, the binding station may be of any type (for example, for binding the signatures by sewing them, gluing them, stapling them and so on).

[0114] In an embodiment, the method comprises the following steps under the control of a control system. However, the control system may be of any type (for example, a computer, microcontroller and the like of a machine of the bookbinding system that directly and / or indirectly controls the other machines as well, of the whole bookbinding system, and so on).

[0115] In an embodiment, the method comprises receiving (by the control system) an indication of an operating speed of the bookbinding system. However, the operating speed may be indicated in any way (for example, in terms of nominal value of the feeding speed, binding speed, book time and so on) and received in any way (for example, entered via any input unit, read from a memory, initialized to a default value that may be customized, fixed to a single possible value and so on).

[0116] In an embodiment, the method comprises receiving (by the control system) an indication of a number of the signatures and of corresponding numbers of the book sheets of the signatures of each book block, the numbers of the book sheets of the signatures having a maximum value. However, this information may be received in any way (for example, from a descriptor stored in a file, from a code printed on the sheets and so on).

[0117] In an embodiment, the method comprises setting (by the control system) a binding speed of the binding station corresponding to the operating speed according to the maximum value of the numbers of the book sheets of the signatures. However, the binding speed may be set in any way (for example, indirectly from the nominal value of the feeding speed, directly from the operating speed and so on).

[0118] In an embodiment, the method comprises setting (by the control system) a feeding speed of the feeding station to a nominal value thereof, corresponding to the operating speed, reduced according to a ratio between a total number of the book sheets and an ideal number of the book sheets of each book block, the total number being equal to the sum of the numbers of the book sheets of the signatures and the ideal number being equal to the number of the signatures multiplied by the maximum value of the numbers of the book sheets of the signatures. However, the feeding speed may be set in any way (for example, by calculating its nominal value and then reducing it, directly, and so on).

[0119] In an embodiment, the method comprises controlling (by the control system) the feeding station to feed the book sheets at the feeding speed and the binding station to bind the signatures at the binding speed. However, the feeding station and the binding station may be controlled in any way (for example, directly, indirectly via corresponding control units, and so on).

[0120] Further embodiments provide additional advantageous features, which may however be omitted at all in a basic implementation. In this respect, it is expressly understood that the features of each of the following embodiments may be combined with the above features either alone or in combination with the features of any number of the other following embodiments. In an embodiment, the feeding station comprises an unwinding station for unwinding a reel on which sheets are printed comprising the book sheets of the book blocks. However, the unwinding station may be of any type (for example, a dedicated machine or comprised in the cutting station, and so on) for any reel (for example, of paper of any weight, finishing, on which only the book sheets or service sheets as well are printed, and so on).

[0121] In an embodiment, the feeding station comprises a cutting station for cutting the sheets from the reel being unwound by the unwinding station. However, the cutting station may be of any type (for example, a dedicated machine or comprising the unwinding station as well, and so on).

[0122] In an embodiment, the feeding station comprises a separating station for transiting the book sheets being cut by the cutting station towards the forming station separating them from each other by a distancing. However, the separating station may be of any type (for example, integrated with the binding station in a corresponding machine, a dedicated machine, and so on) for spacing apart the book sheets in any way (for example, receiving them from the cutting station and then transferring them at higher speed, accelerating them and then transferring them at the same speed, and so on).

[0123] In an embodiment, the method comprises setting (by the control system) a transiting speed of the separating station corresponding to the operating speed. However, the transiting speed may be set in any way (for example, inputting it directly in any way as above, calculating it from the operating speed and so on).

[0124] In an embodiment, the method comprises receiving (by the control system) an indication of a length of the book sheets of each book block. However, this additional information may be received in any way (for example, either the same or different with respect to above).

[0125] In an embodiment, the method comprises setting (by the control system) the binding speed corresponding to the transiting speed being reduced according to the maximum value of the numbers of the book sheets of the signatures multiplied by a sum of the length of the book sheets plus a nominal value of the distancing. However, the binding speed may be set in any way (for example, directly from the transiting speed, indirectly from the operating speed, and so on). In an embodiment, the method comprises setting (by the control system) an unwinding speed of the unwinding station to a nominal value thereof, corresponding to the transiting speed being reduced according to a ratio between the length of the book sheets and the sum of the length of the book sheets plus the nominal value of the distancing, reduced according to the ratio between the total number of book sheets and the ideal number of the book sheets of each book block. However, the unwinding speed may be set in any way (for example, by calculating its nominal value and then reducing it, directly, and so on).

[0126] In an embodiment, the method comprises controlling (by the control system) the unwinding station to unwind the reel at the unwinding speed, the cutting station to cut the sheets according to the length of the book sheets, and the separating station to transit the book sheets at the transiting speed, thereby separating them by the distancing being increased accordingly with respect to the nominal value thereof. However, the unwinding station, the cutting station and the separating station may be controlled in any manner (for example, directly or indirectly via corresponding control units, and so on).

[0127] In an embodiment, the method comprises calculating (by the control system) a simulation of operation of the bookbinding system according to the feeding speed and the binding speed. However, the simulation may be defined in any way (for example, in temporal, spatial terms and so on) and it may be calculated in any way (for example, via an algorithm, a neural network and so on).

[0128] In an embodiment, the method comprises classifying (by the control system) each signature as impossible if the simulation indicates that the binding station would be incapable of receiving the signature at a releasing instant at which the signature would be released by the forming station to the binding station. However, the signatures may be classified as impossible in any way (for example, if their release interferes with push / hold elements or does not allow operation of gripping elements for transporting them towards the functional unit of the binding station, it does not allow their direct receiving by the functional unit, and so on).

[0129] In an embodiment, the method comprises (in response to an error condition defined by one or more impossible signatures) modifying (by the control system) the operation of the bookbinding system for removing the error condition. However, the operation of the bookbinding system may be modified in any way (for example, by modifying the binding speed in correspondence to each impossible signature, reducing the operating speed, and so on).

[0130] In an embodiment, the method comprises (in response to an error condition defined by one or more impossible signatures) determining (by the control system) an alternative simulation of operation of the bookbinding system for making the book blocks with an alternative composition of each book block comprising a different number of signatures and / or of book sheets of each signature. However, the alternative simulation may be calculated in any manner (see above) for the alternative composition determined in any way (for example, among any number of possible compositions, stopping as soon as a satisfactory solution is found, seeking an optimal solution and so on).

[0131] In an embodiment, the alternative simulation involves a reduction of said modifying the operation of the bookbinding system. However, the alternative simulation may reduce the modification of the operation of the bookbinding system in any way (for example, in terms of the number of modifications and / or of extent of the modifications, by any amount up to make it null, and so on).

[0132] In an embodiment, the method comprises (in response to an error condition defined by one or more impossible signatures) outputting (by the control system) an indication of the alternative composition. However, the alternative composition may be output in any way (for example, in text and / or graphic form, displayed on any output device, transmitted remotely, and so on) and in any condition (for example, only when the modification of the operation exceeds a modification threshold or in any case, with a corresponding job that is executed by modifying the operation of the bookbinding system anyway or it is cancelled, and so on).

[0133] In an embodiment, the binding station comprises a functional unit. However, the functional unit may bind the signatures in any way (see above).

[0134] In an embodiment, the binding station comprises a fixed saddle for transporting the signatures being formed by the forming station to the functional unit. However, the signatures may be provided from the forming station to the functional unit in any way (for example, with a different transporting system, directly, and so on).

[0135] In an embodiment, the fixed saddle comprises a saddle plate for receiving the signatures from the forming station. However, the saddle plate may be of any type (for example, with any length, width, and so on).

[0136] In an embodiment, the fixed saddle comprises a plurality of pegs being equidistant to each other for pushing the signatures along the saddle plate. However, the pegs may be of any type (for example, in any number, with any pitch, of any shape / size, and so on).

[0137] In an embodiment, the fixed saddle comprises a moving system for moving the pegs continuously along the saddle plate. However, the moving system may be of any type (for example, based on chain, belt, gears, and so on).

[0138] In an embodiment, the method comprises calculating (by the control system) the simulation comprising an indication of corresponding receiving positions of the pegs along the saddle plate at the releasing instant of each signature. However, the receiving positions may be defined in any way (for example, relative to any reference, such as the beginning of the saddle plate, the releasing position of the signatures on the saddle plate, and so on).

[0139] In an embodiment, the method comprises classifying (by the control system) each signature as impossible if the simulation indicates that the receiving position of an interfering peg of the pegs would be comprised within an encumbrance of the signature on the saddle plate at the corresponding releasing instant, the encumbrance being defined according to a releasing position of the signatures on the saddle plate and the length of the book sheets. However, the peg may be considered interfering in any way (for example, if it falls exactly within the length of the signature, within the length of the signature plus any safety margin, and so on).

[0140] In an embodiment, the method comprises calculating (by the control system) an increase in the operating speed in response to no impossible signature for which the simulation indicates that the binding station would remain capable of receiving each signature at the corresponding releasing instant. However, the operating speed may be increased in any way (for example, by any fixed / variable step until impossible signatures appear, up to a maximum possible value, in either absolute or relative terms, and so on) and under any conditions (for example, when there are no impossible signatures, their number is lower than a minimum value, the corresponding modification of the operation of the bookbinding system is lower than a minimum value, and so on).

[0141] In an embodiment, the method comprises increasing (by the control system) the operating speed according to the corresponding increase. However, the operating speed may be increased in any way (for example, simply by suggesting it, requiring a manual confirmation, automatically, and so on).

[0142] In an embodiment, said step of modifying the operation of the bookbinding system in response to the error condition comprises modifying (by the control system) the binding speed in correspondence to each impossible signature according to a modification whereby the simulation indicates that the binding station would become capable of receiving the impossible signature at the corresponding releasing instant. However, the modification of the binding speed may be of any type (for example, with the binding speed always being reduced, reduced or increased, always increased, and so on).

[0143] In an embodiment, said step of modifying the binding speed in correspondence to each impossible signature comprises calculating (by the control system) an indication of a delay and of an advance of the binding station whereby the simulation indicates that the binding station would become capable of receiving the impossible signature at the corresponding releasing instant. However, the delay and the advance may be of any type (for example, in either spatial or temporal terms, set to a minimum value thereof or taking into account any safety margin, and so on).

[0144] In an embodiment, said step of modifying the binding speed in correspondence to each impossible signature comprises selecting (by the control system) one between the delay and the advance according to a selection policy. However, the selection policy may be of any type (for example, for avoiding idle cycles in the binding station, for minimizing the modification of the binding speed, and so on).

[0145] In an embodiment, said step of modifying the binding speed in correspondence to each impossible signature comprises modifying (by the control system) the binding speed in correspondence to the impossible signature by increasing or reducing the binding speed according to the delay or the advance being selected. However, the binding speed may be increased / decreased in any way (for example, with any acceleration and deceleration, with any intermediate section at constant speed, even null, and so on). In an embodiment, said modifying the operation of the bookbinding system in response to the error condition comprises reducing (by the control system) the operating speed in response to a number of the impossible signatures exceeding an error threshold and / or to the modification of the binding speed in correspondence to at least one of the impossible signatures exceeding a modification threshold. However, the operating speed may be reduced in any way (for example, by any fixed / variable step, up to a maximum possible value, in either absolute or relative terms, simply by suggesting it, by requiring a manual confirmation, automatically, and so on) and under any condition (for example, when the number of the impossible signatures exceeds any error threshold, when the modification of the binding speed in correspondence to at least one of the impossible signatures exceeds any modification threshold, when both conditions occur, and so on).

[0146] In an embodiment, said step of reducing the operating speed comprises reducing (by the control system) the unwinding speed in response to the number of the impossible signatures exceeding the error threshold, thereby increasing the distancing accordingly. However, the unwinding speed may be reduced in any way (for example, in terms of increment of the nominal value of the distancing, directly, and so on) and under any conditions (for example, in response to the number of the impossible signatures exceeding the error threshold, in response to the modification of the binding speed in correspondence to at least one of the impossible signatures exceeding the modification threshold, and so on).

[0147] In an embodiment, said step of reducing the operating speed comprises reducing (by the control system) the transiting speed in response to the modification of the binding speed in correspondence to at least one of the impossible signatures exceeding the modification threshold. However, the transiting speed may be reduced in any way (for example, directly, in terms of the operating speed, and so on) and under any conditions (for example, in response to the modification of the binding speed in correspondence to at least one of the impossible signatures exceeding the modification threshold, in response to the number of the impossible signatures exceeding the error threshold, and so on).

[0148] In an embodiment, the method comprises what follows in response to a notification of each of one or more service sheets, of the sheets being printed on the reel between the book sheets, being discarded by the cutting station. However, the service sheets may be in any number and of any type (for example, comprising printing tests, control information, and so on), and their presence may be detected at any location (for example, in the cutting station, the unwinding station, the separating station, and so on) and notified in any way (for example, by monitoring the corresponding station, listening for corresponding messages sent therefrom, and so on).

[0149] In an embodiment, the method comprises, in response to such notification, reducing (by the control system) the binding speed in correspondence to each service sheet for compensating a corresponding shortage in said feeding the book sheets. However, the binding speed may be reduced in any manner (for example, with any acceleration and deceleration, with any intermediate section at constant speed, even null, and so on).

[0150] In an embodiment, the forming station comprises an upper support and a lower support. However, the upper / lower supports may be of any type (for example, either the same or different from each other, such as each comprising one or more cylinders, blades, and so on).

[0151] In an embodiment, the upper support is controllable to close for receiving the book sheets of each signature under formation and to open for releasing each signature being formed onto the lower support. However, the upper support may be closed / opened in any way (for example, by extracting / retracting a piston from a barrel of each cylinder, pushing / pulling each blade, and so on).

[0152] In an embodiment, the lower support is controllable to close for receiving each signature from the upper support and to open for releasing each signature onto the sewing station. However, the lower support may be closed / opened in any way (for example, either the same or different with respect to the upper support).

[0153] In an embodiment, the method comprises controlling (by the control system) the lower support to close with a closing time reduced with respect to a nominal value thereof according to a ratio between the number of the book sheets of the signature under formation on the upper support and the maximum value of the numbers of the book sheets of the signatures. However, the nominal value of the closing time may be of any type (for example, fixed, depending on the type of paper, and so on). In any case, such a feature may also be used stand-alone, independently of the above- mentioned control of the bookbinding system.

[0154] Generally, similar considerations apply if the same solution is implemented with an equivalent method, provided that it remains within the scope of the claims. In any case, the method may be performed by using similar steps with the same functions of more steps or portions thereof, removing some non-essential steps or adding further optional steps; moreover, the steps may be performed in a different order, concurrently or in an interleaved way (at least in part).

[0155] An embodiment provides a computer program configured to cause the control system of the bookbinding system to perform the method of above when the computer program is executed on the control system. An embodiment provides a computer program product comprising one or more non-transitory computer-readable storage media having program instructions collectively stored on the computer-readable storage media, the program instructions being readable by a control system of a bookbinding system to cause the control system to perform the same method. However, the (computer) program may be of any type (for example, implemented as a stand-alone module, as a plug-in program for a pre-existing program, such as a manager of the sewing machine, even directly into the latter, and so on) and it may be used on any control system (see above).

[0156] Generally, similar considerations apply if the program is structured in a different way or it has different / additional modules or functions, provided that it remains within the scope of the claims. Likewise, the memory structures may be of other types, or they may be replaced with equivalent entities (not necessarily consisting of physical storage media). The program may take any form suitable to be used by the control system, thereby configuring it to perform the desired operations; particularly, the program may be in the form of external or resident software, firmware, or microcode (in either object code or source code), for example, to be compiled or interpreted. Moreover, it is possible to provide the program on any computer readable storage medium. The storage medium is any tangible medium (different from transitory signals per se) that may retain and store instructions for use by the control system. For example, the storage medium may be of electronic, magnetic, optical, electromagnetic, infrared, or semiconductor type; examples of such storage medium are fixed disks (where the program may be pre-loaded), removable disks, memory keys (for example, of USB type), and the like. The program may be downloaded to the control system from the storage medium or via a network (for example, the Internet, a wide area network and / or a local area network comprising transmission cables, optical fibers, wireless connections, network devices); one or more network adapters in the computing system receive the program from the network and forward it for storage into one or more storage devices of the control system. In any case, the solution according to an embodiment of the present disclosure lends itself to be implemented even with a hardware structure (for example, by electronic circuits integrated on one or more chips of semiconductor material), or with a combination of software and hardware suitably programmed or otherwise configured.

[0157] An embodiment provides a bookbinding system for applying the method of above. In particular, the bookbinding system comprises the feeding station, the forming station, the binding station, and the control system. In an embodiment, the control system comprises means configured for performing such method. In an embodiment, the control system comprises a circuit configured for performing each step of the same method. However, the bookbinding system may be of any type (see above).

[0158] An embodiment provides a bookbinding plant comprising such bookbinding system. However, the bookbinding plant may be of any type (for example, comprising any number, including zero, of stations of any type downstream and / or upstream of the bookbinding system).

[0159] In an embodiment, the bookbinding plant comprises one or more downstream stations for providing the book sheets to the bookbinding system. However, the downstream stations may be in any number and of any type (for example, printers of any type, such as digital, analog, and so on).

[0160] In an embodiment, the bookbinding plant comprises one or more upstream stations for completing the book blocks provided by the bookbinding system into corresponding books. However, the upstream stations may be in any number and of any type (for example, perfect-binding machines, three-knife trimming machines, casing-in machines, and so on).

[0161] Generally, similar considerations apply if the bookbinding system and the bookbinding plant each one has a different structure, comprises equivalent components (for example, of different materials) or has other operative characteristics, provided that it remains within the scope of the claims. In any case, every component thereof may be separated into more elements, or two or more components may be combined together into a single element; moreover, each component may be replicated to support the execution of the corresponding operations in parallel. It is expressly understood that, unless specified otherwise, any interaction between different components (including their mutual arrangement) generally does not need to be continuous, and it may be either direct or indirect through one or more intermediaries.

Claims

CLAIMS1. A method (600) for controlling a bookbinding system (100) to make book blocks each comprising a plurality of signatures each comprising one or more book sheets, wherein the bookbinding system (100) comprises a feeding station (103) for feeding the book sheets in succession, a forming station (121) for forming the signatures from the corresponding book sheets being fed by the feeding station (103) and a binding station (124) for binding the signatures of each book block being formed by the forming station (121) to each other, wherein the method (600) comprises, under the control of a control system (130): receiving (604), by the control system (130), an indication of an operating speed of the bookbinding system (100), receiving (608), by the control system (130), an indication of a number of the signatures and of corresponding numbers of the book sheets of the signatures of each book block, the numbers of the book sheets of the signatures having a maximum value, setting (610), by the control system (130), a binding speed of the binding station (124) corresponding to the operating speed according to the maximum value of the numbers of the book sheets of the signatures, setting (612-614), by the control system (130), a feeding speed of the feeding station (103) to a nominal value thereof, corresponding to the operating speed, reduced according to a ratio between a total number of the book sheets and an ideal number of the book sheets of each book block, the total number being equal to the sum of the numbers of the book sheets of the signatures and the ideal number being equal to the number of the signatures multiplied by the maximum value of the numbers of the book sheets of the signatures, and controlling (684), by the control system (130), the feeding station (103) to feed the book sheets at the feeding speed and the binding station (124) to bind the signatures at the binding speed.

2. The method (600) according to claim 1, wherein the feeding station (103) comprises an unwinding station (106) for unwinding a reel on which sheets are printed comprising the book sheets of the book blocks, a cutting station (112) for cutting the sheets from the reel being unwound by the unwinding station (106) and a separating station (118) for transiting the book sheets being cut by the cutting station (112)towards the forming station (121) separating them from each other by a distancing, wherein the method (600) comprises: setting (604), by the control system (130), a transiting speed of the separating station (118) corresponding to the operating speed, receiving (608), by the control system (130), an indication of a length of the book sheets of each book block, setting (610), by the control system (130), the binding speed corresponding to the transiting speed being reduced according to the maximum value of the numbers of the book sheets of the signatures multiplied by a sum of the length of the book sheets plus a nominal value of the distancing, setting (612-614), by the control system (130), an unwinding speed of the unwinding station (106) to a nominal value thereof, corresponding to the transiting speed being reduced according to a ratio between the length of the book sheets and the sum of the length of the book sheets plus the nominal value of the distancing, reduced according to the ratio between the total number of book sheets and the ideal number of the book sheets of each book block, and controlling (684), by the control system (130), the unwinding station (106) to unwind the reel at the unwinding speed, the cutting station (112) to cut the sheets according to the length of the book sheets, and the separating station (118) to transit the book sheets at the transiting speed, thereby separating them by the distancing being increased accordingly with respect to the nominal value thereof.

3. The method (600) according to claim 1 or 2, wherein the method (600) comprises: calculating (616), by the control system (130), a simulation of operation of the bookbinding system (100) according to the feeding speed and the binding speed, classifying (618-628), by the control system (130), each signature as impossible if the simulation indicates that the binding station (124) would be incapable of receiving the signature at a releasing instant at which the signature would be released by the forming station (118) to the binding station (124), and in response to an error condition defined by one or more impossible signatures: modifying (630-670), by the control system (130), the operation of the bookbinding system (100) for removing the error condition, and / ordetermining (672-678), by the control system (130), an alternative simulation of the operation of the bookbinding system (100) for making the book blocks with an alternative composition of each book block comprising a different number of signatures and / or of book sheets of each signature, the alternative simulation involving a reduction of said modifying the operation of the bookbinding system, and outputting (680), by the control system (130), an indication of the alternative composition.

4. The method (600) according to claim 3 when dependent on claim 2, wherein the binding station (124) comprises a functional unit (154) and a fixed saddle (151) for transporting the signatures being formed by the forming station (121) to the functional unit (154), the fixed saddle (151) comprising a saddle plate (157) for receiving the signatures from the forming station (121), a plurality of pegs (160a-160d) being equidistant to each other for pushing the signatures along the saddle plate (157) and a moving system (163) for moving the pegs (160a-160d) continuously along the saddle plate (157), and wherein the method (600) comprises: calculating (616), by the control system (130), the simulation comprising an indication of corresponding receiving positions of the pegs (160a-160d) along the saddle plate (157) at the releasing instant of each signature, and classifying (618-628), by the control system (130), each signature as impossible if the simulation indicates that the receiving position of an interfering peg of the pegs (160a-160d) would be comprised within an encumbrance of the signature on the saddle plate (157) at the corresponding releasing instant, the encumbrance being defined according to a releasing position of the signatures on the saddle plate and the length of the book sheets.

5. The method (600) according to claim 3 or 4, wherein the method (600) comprises: calculating (632-640), by the control system (130), an increase in the operating speed in response to no impossible signature for which the simulation indicates that the binding station (124) would remain capable of receiving each signature at the corresponding releasing instant, and increasing (642), by the control system (130), the operating speed according to the corresponding increase.

6. The method (600) according to any claim from 3 to 5, wherein said modifying (630-670) the operation of the binding system (100) in response to the error condition comprises: modifying (646-662), by the control system (130), the binding speed in correspondence to each impossible signature according to a modification whereby the simulation indicates that the binding station (124) would become capable of receiving the impossible signature at the corresponding releasing instant.

7. The method (600) according to claim 6, wherein said modifying (646-662) the binding speed in correspondence to each impossible signature comprises: calculating (648-650), by the control system (130), an indication of a delay and of an advance of the binding station (124) whereby the simulation indicates that the binding station (124) would become capable of receiving the impossible signature at the corresponding releasing instant, selecting (654), by the control system (130), one between the delay and the advance according to a selection policy, and modifying (656-660), by the control system (130), the binding speed in correspondence to the impossible signature by increasing or reducing the binding speed according to the delay or the advance being selected.

8. The method (600) according to claim 7, wherein said modifying (630-670) the operation of the bookbinding system (100) in response to the error condition comprises: reducing (664-670), by the control system (130), the operating speed in response to a number of the impossible signatures exceeding an error threshold and / or to the modification of the binding speed in correspondence to at least one of the impossible signatures exceeding a modification threshold.

9. The method (600) according to claim 8 when dependent on claim 2, wherein said reducing (664-670) the operating speed comprises: reducing (664-666), by the control system (130), the unwinding speed in response to the number of the impossible signatures exceeding the error threshold, thereby increasing the distancing accordingly, and / or reducing (668-670), by the control system (130), the transiting speed in response to the modification of the binding speed in correspondence to at least one ofthe impossible signatures exceeding the modification threshold.

10. The method (600) according to any claim from 1 to 9 when dependent on claim 2, wherein the method (600) comprises, in response to a notification of each of one or more service sheets, of the sheets being printed on the reel between the book sheets, being discarded by the cutting station (112): reducing (686-692), by the control system (130), the binding speed in correspondence to each service sheet for compensating a corresponding shortage in said feeding the book sheets.

11. The method (600) according to any claim from 1 to 10, wherein the forming station (121) comprises an upper support (172) and a lower support (175), the upper support (172) being controllable to close for receiving the book sheets of each signature under formation and to open for releasing each signature being formed onto the lower support (175), and the lower support (175) being controllable to close for receiving each signature from the upper support (172) and to open for releasing each signature onto the binding station (124), and wherein the method (600) comprises: controlling (682), by the control system (130), the lower support (175) to close with a closing time reduced with respect to a nominal value thereof according to a ratio between the number of the book sheets of the signature under formation on the upper support (172) and the maximum value of the numbers of the book sheets of the signatures.

12. A computer program (500) configured to cause the control system (130) of the bookbinding system (100) to perform the method (600) according to any claim from 1 to 11 when the computer program (600) is executed on the control system (130).

13. A computer program product comprising one or more non-transitory computer-readable storage media having program instructions collectively stored on the computer-readable storage media, the program instructions being readable by a control system of a bookbinding system to cause the control system to perform the method according to any claim from 1 to 11.

14. A bookbinding system (100) for making book blocks each comprising a plurality of signatures each comprising one or more book sheets, wherein the bookbinding system (100) comprises a feeding station (103) for feeding the book sheets in succession, a forming station (121) for forming the signatures from thecorresponding book sheets being fed by the feeding station (103), a binding station (124) for binding the signatures of each book block being formed by the forming station (121) to each other, and a control system (130) comprising means (136) configured for performing the method (600) according to any claim from 1 to 11.

15. A bookbinding system for making book blocks each comprising a plurality of signatures each comprising one or more book sheets, wherein the bookbinding system comprises a feeding station for feeding the book sheets in succession, a forming station for forming the signatures from the corresponding book sheets being fed by the feeding station, a binding station for binding the signatures of each book block being formed by the forming station to each other, and a control system comprising a circuit configured for performing each step of the method according to any claim from 1 to 11.

16. A bookbinding plant comprising the bookbinding system (100) according to claim 14 or 15, one or more downstream stations for providing the book sheets to the bookbinding system (100), and one or more upstream stations for completing the book blocks provided by the bookbinding system (100) into corresponding books.

Images