Synchronous driving method and system

Abstract

The invention relates to a method and a system for synchronously driving at least one treatment device (1, 1.1, 1.2, 1.3) for treating a substrate (S) moved by a conveying device (10, 11, 12). The method comprises: acquiring a position signal (s0) by means of an encoder (3), said signal providing a position associated with the displacement of the substrate (S) and / or of the transport means (10, 11, 12) at each time; and driving the processing device (1, 1.1, 1.2, 1.3) when the position provided by the position signal (s0) from the positioning point (Pp) through which the substrate (S) passes takes a given driving position value (V0). The method is characterized in that it further comprises: measuring and / or acquiring data relating to displacement-dependent physical and / or movement characteristics of the substrate (S) and / or of the conveying means (10, 11, 12); and correcting the position signal and / or the drive position value (V0; v; v ', VA, VB, VC) to drive the processing means (1, 1.1, 1.2, 1.3).

Description

Technical Field

[0001] The present invention relates to a synchronous drive method and system for a substrate processing device such as a panel, wherein the substrate is displaced relative to the processing device by a transport device such as a conveyor belt or a roller conveyor.

[0002] These drive methods and systems allow actions such as digital printing, coating, cutting, stamping or engraving to be performed on a substrate by a processing device in synchronization with the displacement of the substrate.

[0003] The present invention is particularly applicable to the industry of digital printing of substrates, and also relates to a digital printer comprising a synchronous drive system. Background Art

[0004] Methods and systems for synchronously driving a substrate processing device using position signals obtained by an encoder are known. The position signals provide a position associated with the displacement of the substrate at each moment.

[0005] Rotary encoders are used in transport systems consisting of conveyor belts or roller conveyors. They are functionally coupled to the rotating shaft of the conveyor belt feed rollers or roller conveyor. These encoders provide the angular position of the rotating shaft, which is correlated to the position of the substrate and / or the displacement of the transport system.

[0006] In order to drive the processing device synchronously with the displacement of the substrate, the processing device is driven when the position associated with the displacement provided by the position signal takes a given driving position value from a positioning point passed by the substrate.

[0007] The driving position value is predetermined corresponding to the distance between the positioning point and the driving point at which the processing device should perform an action on the substrate.

[0008] Known synchronous drive methods and systems have the disadvantage that they do not allow optimal precision to be achieved when performing synchronous actions on the substrate due to possible erroneous delays or advances relative to the nominal execution time and / or misalignments relative to the nominal position of the action performed on the substrate.

[0009] This drawback is particularly relevant in methods and systems for digital printing of substrates that seek to provide high printing speeds as well as high printing resolutions.

[0010] The printing resolution of digital inkjet printers can be increased by using printheads that eject smaller droplet volumes, allowing for an increased number of pixels per print area.

[0011] The printing resolution of a single-pass digital inkjet printer can also be increased by reducing the printing speed, which allows increasing the number of inkjet drop ejections per unit length in the direction of displacement of the substrate and thus increasing the number of pixels per printed unit length in said direction.

[0012] Therefore, it is desirable to improve the synchronization accuracy of known methods and systems for digital inkjet printing on substrates. Improving synchronization accuracy directly impacts improvements in print resolution. This is because achieving higher print resolution at a given print speed requires increasing the number of pixels per print area or per unit length along the substrate's displacement direction, thereby necessitating higher synchronization accuracy to prevent delays or advances in the ejection timing of print ink drops and / or misalignment of the ejected ink drops on the substrate.

[0013] Patent document WO 2021 / 146595 A1 discloses a synchronous drive system for substrate processing devices used for digital printing on substrates, which are displaced by a conveyor belt. To improve synchronization accuracy, the system incorporates an improved encoder compared to a pure rotary encoder. This improved encoder includes an encoder strip driven by two rollers and contact-positioned on the conveyor belt. However, a disadvantage of this encoder is its complex construction, which is transferred to the system.

[0014] In view of the aforementioned shortcomings or limitations of currently existing solutions, a solution is needed that allows improving the synchronization accuracy provided by synchronized drive methods and systems for known substrate processing devices while allowing for a simple implementation or construction, thereby requiring minimal modifications to the known synchronized drive methods and systems. Summary of the Invention

[0015] To achieve this object and solve the technical problems discussed so far, the present invention provides, besides providing additional advantages obtainable later, a method for synchronous driving of at least one substrate processing device when the substrate is displaced by a transport device.

[0016] The method includes: obtaining a position signal by an encoder, the signal providing a position associated with the displacement of the substrate and / or the conveying device at each moment; and driving the processing device when the position provided by the position signal from the positioning point passed by the substrate takes a given drive position value.

[0017] According to the invention, the method further comprises: measuring and / or obtaining data about physical and / or motion characteristics of the substrate and / or the conveying device related to the displacement; and correcting the position signal and / or the drive position value to drive the processing device based on the obtained measurements or data.

[0018] Thus, once the position signal and / or the drive position value are corrected, the processing device is driven when the position provided by the corrected position signal from the set point takes the uncorrected drive position value and / or when the position provided by the uncorrected position signal from the set point takes the corrected drive position value.

[0019] The position associated with the displacement of the substrate and / or the conveying device is specifically to be understood as the position of a moving element, in particular the position of a moving element of the substrate and / or the conveying device, such as the substrate itself, the belt body of a conveyor belt, the rotation axis of a feed roller corresponding to the belt body, the rotation axis of a roller of a roller conveyor, so that this position is related to the position of the substrate and / or the conveying device in its displacement.

[0020] The position associated with the displacement is provided by a position signal generated by a position encoder in a manner known per se. Specifically, an encoder is functionally coupled to the moving element, the movement of which is related to the displacement of the substrate and / or the conveyor. The encoder can, for example, be linear or rotary.

[0021] For example, in the case of a conveying device for substrates consisting of a conveyor belt or roller conveyor, a rotary encoder can be used, which is functionally coupled to the rotating shaft of the feed rollers or conveyor rollers of the belt body, which makes it possible to obtain a position signal which provides a position associated with the displacement via the angular position of the rotation of the shaft.

[0022] The uncorrected drive position value is a predetermined value that corresponds to the value of the position provided by the uncorrected position signal from the positioning point, so that the processing device can be driven when the substrate has been displaced a fixed distance from said point.

[0023] Since the position associated with the displacement, which is provided by the position signal generated by the encoder, is related to the displacement of the substrate and / or the conveying device, the uncorrected drive position value can be obtained from the relationship consisting of, for example, a theoretical function, such as a kinematic function, which relates the position change provided by the position signal to the displacement distance of the substrate between two points.

[0024] Unlike known synchronous drive methods, the synchronous drive method according to the present invention uses a corrected position signal and / or drive position value. This correction improves synchronization accuracy because it allows for consideration of factors that influence the actual displacement of the substrate and / or conveyor, factors that would not be accounted for if uncorrected position signals and uncorrected drive values ​​were used, as in the prior art.

[0025] In this regard, the applicant has discovered that, because the synchronous drive method for determining uncorrected drive position values ​​involves a theoretical relationship between a position associated with a displacement and the actual displacement of the substrate and / or the conveyor, the use of this theoretical relationship can itself constitute a significant source of precision error. This precision error is introduced by the need to formulate assumptions to define the theoretical relationship.

[0026] Thus, the Applicant has observed that, for example, in the case where the transport device consists of a conveyor belt having a rotary encoder functionally coupled to the rotary shaft of the feed rollers of the belt, there may be in particular slippage between the shaft and the encoder and / or between the belt and the rollers and / or between the substrate and the belt, as well as deformations of the belt itself, which can introduce precision errors that are not taken into account in the prior art methods.

[0027] Furthermore, it has been observed that these behaviors depend on the system's usage scenario, in particular, for example, on substrate load, displacement speed, continuous operation time, etc. Consequently, prior art synchronous drive methods cannot take this behavior into account, since the drive position value remains constant. Unlike prior art synchronous drive methods, the present invention takes this behavior into account by enabling a correction to dynamically change the position signal and / or the drive position value during system use.

[0028] In fact, it was observed that these behaviors became more pronounced when the displacement speed increased or the substrate load increased.

[0029] According to another aspect, the present invention also relates to a synchronous drive system for at least one substrate processing device, the substrate being displaced relative to the device by a conveyor device. This system is configured to implement the synchronous drive method described herein. In this sense, all that has been described with respect to the synchronous drive method according to the present invention applies to this system, and vice versa.

[0030] The system according to the present invention comprises: a device for measuring and / or obtaining data about physical and / or motion characteristics of the substrate and / or the conveying device related to the displacement; and a control device, which is operably connected to the encoder to obtain a position signal, to the device for detecting the passage of the substrate through a positioning point, to the device for measuring and / or obtaining data about physical and / or motion characteristics of the substrate and / or the conveying device related to the displacement, and to the processing device.

[0031] The device for detecting the passage of the substrate through the positioning point particularly comprises at least one detection sensor for detecting the passage of a reference element fixed to the substrate. This reference element can be attached to or integrated into the substrate, in particular forming a part of the substrate. For example, it is conceivable that the reference element is formed by the leading edge of the substrate in the direction of its displacement. The detection sensor can be, for example, a contrast detection sensor in a manner known per se.

[0032] The control device is used to execute the synchronous driving method according to the present invention. The control device particularly includes at least one programmable device, for example, having FPGA programmable logic and / or software.

[0033] The processing device used in the present invention can be any type of device for performing an action on a displaced substrate. For example, a substrate measuring device, a coating device, a cutting device, an imprinting device, an engraving device, a digital printing device, etc. can all be considered a processing device.

[0034] In particular, the present invention is applicable to a digital inkjet printing device that is part of, and in particular constitutes, an inkjet printer, particularly a single-pass inkjet printer. As previously mentioned, the synchronous driving method for the digital inkjet printing device can increase the printing speed of a substrate and / or improve the printing resolution.

[0035] The digital printing device includes a plurality of printheads having a plurality of ink nozzles arranged in a direction perpendicular to the displacement. Specifically, the digital printing device is configured to eject droplets having a volume of less than or equal to 20 pL, preferably 10 pL, and more preferably 5 pL, and / or to provide a printing resolution of greater than or equal to 360 dpi, preferably 720 dpi, and more preferably 1200 dpi, in a direction perpendicular to the displacement. This resolution is determined by the physical distance between the nozzles arranged in the printhead.

[0036] According to another aspect, the present invention also relates to a digital substrate printer, comprising: an inkjet printer, in particular a single-pass inkjet printer, comprising a printing device; a transport device for shifting a substrate to be printed by the inkjet printer; an encoder for acquiring a position signal; and a device for detecting the passage of the substrate through a positioning point.

[0037] The digital printing machine for substrates according to the present invention comprises a synchronous driving system for the digital printing device for synchronously driving the digital printing device of the substrate (S) when the substrate (S) is displaced by the conveying device.

[0038] In this way, the synchronization accuracy provided by the synchronized drive methods and systems of known substrate processing devices can be improved while allowing a simple implementation or construction since it enables the use of encoders without modification with minimal construction adjustments. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The following drawings are included to illustrate different practical embodiments of the invention by way of example and not limitation.

[0040] Figure 1 An embodiment of a synchronous drive method and system according to the prior art is schematically shown. The figure shows a schematic elevation view of the system and its different components, indicating the interaction therebetween to perform the method.

[0041] Figures 2 to 4Different general embodiments of the synchronous drive method and system according to the invention are schematically shown. The figures show schematic elevations of the system and its different components, indicating the interaction therebetween to perform the method.

[0042] Figures 5 to 7 Schematically illustrates different embodiments of the method and system according to the present invention, which are applicable to Figure 4 Likewise, the figures show schematic elevations of the system and its various components, indicating the interaction therebetween to perform the method.

[0043] Figure 8 and 9 Schematically shows different embodiments of the method and system according to the invention, which are also applicable to Figure 4 The embodiment shown and can be used with Figures 5 to 7 Each of these figures shows a schematic plan view of the system and its different components.

[0044] 10 to 12 schematically illustrate exemplary embodiments for processing uncorrected and corrected position signals according to the method and system of the present invention, which are applicable to Figure 4 Specifically, this exemplary embodiment can be used with Figures 4 to 9 The different embodiments shown are applicable in combination.

[0045] Figures 13 to 15 Another embodiment of the synchronous driving method and system according to the present invention is schematically shown, which includes multiple processing devices. Figure 4 The preferred specific embodiments of the preferred general embodiment are shown. The figures show schematic elevations of the system and its different components, indicating the interaction therebetween to perform the method. Figure 13 and Figure 15 Different embodiments are involved.

[0046] Figure 16 Another embodiment of the synchronous driving method and system according to the present invention is schematically shown, which includes multiple processing devices. This embodiment also constitutes Figure 4 Likewise, the figure shows a schematic elevational view of the system and its different components, indicating the interaction therebetween to perform the method.

[0047] Figure 17 and 18 Schematically illustrates different embodiments of the method and system according to the present invention, which are applicable to Figures 13 to 15 The embodiment shown and Figure 16 The embodiment shown. Figure 17A schematic plan view of the system and its different components is shown. Figure 18 A detailed schematic diagram of a processing device consisting of a digital printing device as part of a single-pass inkjet printer is shown. DETAILED DESCRIPTION

[0048] Figure 1 A known synchronous drive method and system is shown for synchronizing a processing device (1) for a plate-like substrate (S) which is displaced from left to right as shown in the figure by a conveying device (10).

[0049] The conveying device consists of a conveyor belt (10) comprising a belt (11) or a tape that supports a substrate (S) during its displacement, the belt or tape moving along a closed loop fed by two feed rollers. A drive motor (12) is coupled to the shaft of one of the belt's feed rollers (11) and an encoder (3) is coupled to the shaft of the other feed roller.

[0050] Position signal Obtained by an encoder (3), the signal provides a position associated with the displacement of the substrate (S) and / or the conveying device (10) at each moment, consisting of the angular position of the rotation of the axis of the feed roller of the belt (11) to which the encoder (3) is coupled, this angular position being related to the displacement of the substrate (S) and the belt (11).

[0051] When the angular position of the positioning point (Pp) passed by the reference element (R) from the substrate (S) takes a given driving position value (V0), the processing device (1) is driven at the driving point (Pi). The reference element (R) passing through the positioning point (Pp) is detected by the detection sensor (2) for detecting the reference element (R).

[0052] The angular position is determined by the position signal Provides location signal The and drive position values ​​(V0) are processed in a position acquisition module (4) which is part of the control device of the system.

[0053] The position acquisition module (4) of the processing device is operatively connected to the processing device (1), the detection sensor (2) and the encoder (3) to implement a synchronous driving method of the processing device (1) on the substrate (S).

[0054] like Figures 2 to 4 As shown, in particular, unlike the prior art, according to the present invention, the method comprises: measuring and / or obtaining data on physical and / or motion characteristics of the substrate (S) and / or the conveying device (10) related to the displacement; and correcting the position signal based on the obtained measurements or data and / or drive position value (V0; V) to drive processing device (1).

[0055] Uncorrected position signal obtained from encoder (3) and / or the uncorrected driving position value (V0) processed in the position acquisition module (4) of the control device is corrected to obtain a corrected position signal and / or a corrected drive position value (V). The correction is performed by a position correction module (5) which, together with the position acquisition module (4), is part of the control device of the system.

[0056] The position acquisition module (4) and the position correction module (5) of the control device are operatively connected to each other and to the processing device (1), the detection sensor (2), the encoder (3), and the measuring device (2.1, 2.2; 7) for measuring data on physical and / or motion characteristics related to displacement of the substrate (S) and / or the conveying device (10) and / or the data acquisition device (6) for obtaining the data to implement a synchronous driving method of the substrate (S) by the processing device (1).

[0057] like Figure 2 As shown, it is envisaged that the device for acquiring data on displacement-related physical and / or movement characteristics of the substrate (S) and / or the transport device (10) comprises, for example, a data log (6) for storing and / or processing said data.

[0058] like Figure 3 As shown, it is envisaged that the means for measuring displacement-related physical and / or motion characteristics of the substrate (S) and / or the conveying device (10) include, for example, a measuring sensor (7), such as a speed sensor for the belt (11) and / or the substrate (S) when passing through the measuring point (Pm). Similarly, any type of sensor can be used to measure physical characteristics such as the weight of the substrate or other motion characteristics such as the acceleration of the belt and / or the substrate (S) at the measuring point (Pm).

[0059] The measurements and / or data obtained are used to correct the position signal in the position correction module (5) of the system control device or drive position value (V0; V). For example, the correction can be performed based on modifying or adjusting the theoretical relationship between the position associated with the displacement obtained by the encoder (3) and the actual position of the displacement of the substrate (S) and / or the belt (11) of the conveyor (10). Thus, for example, if the belt (11) moves at a constant nominal displacement speed, the speed having an influence on the uncorrected drive position value (V0) allows the drive position value (V0) to be corrected in real time based on the measured speed of the belt (11) or the substrate (S) at the measuring point (Pm).

[0060] Now refer to Figures 4 to 9 The method according to the invention comprises detecting the passage of a reference element (R; Q, Q') fixed to a substrate (S) and / or a conveying device (10), in particular to a belt (11), through said passage point (Pa, Ps), obtaining a position change (Δ) between a preceding passage point (Pa) and a succeeding passage point (Ps), the position being determined by an uncorrected position signal supply.

[0061] According to the present invention, the position signal is adjusted based on the change (Δ) For example, the position change (Δ) can be used to estimate the displacement speed of the belt body (11) between the previous passing point (Pa) and the next passing point (Ps), so that the constant nominal speed for determining the uncorrected driving position value (V0) can be adjusted and the corrected driving position value (V) can be obtained thereby.

[0062] like Figures 4 to 9 As shown, the device for measuring displacement-related physical and / or movement characteristics of a substrate (S) and / or a conveying device (10) comprises, for example, at least one detection sensor (2, 2.1, 2.2; 2.3; 2.4) for detecting the passage of a reference element (R; Q; Q') fixed to the substrate (S) and / or the conveying device (10), in particular to the belt body (11) of the conveyor belt (10), through a passing point (Pa, Ps).

[0063] The position change (Δ) between the passing points (Pa, Ps) is obtained by a position change acquisition module (8) as part of the system control device. The module (8) is operatively connected to the detection sensors (2, 2.1, 2.2, 2.3, 2.4), the position acquisition module (4) and the position correction module (5).

[0064] Especially Figure 4 As can be seen, the position change acquisition module (8) obtains the uncorrected position signal of the position acquisition module (4) at the time when the reference element (R; Q; Q') of the substrate (S) and / or the conveying device (10) passes through the corresponding point (Pa, Ps). The position is provided, which is detected by the corresponding detection sensor (2, 2.1, 2.2, 2.3, 2.4). The same module (8) calculates the change (Δ) by subtracting the position of the previous passing point (Pa) from the position of the subsequent passing point (Ps). The change (Δ) is sent to the position correction module (5) in order to correct the position signal communicated to the processing device (1) for synchronous driving thereof at the driving point (Pi) based on the change and / or drive position value (V0; V).

[0065] According to the present invention, preferably, the position signal is and / or the drive position value (V0; V) is corrected by obtaining a difference (δ) between a reference change value (Δ0) of the position between the passing points (Pa, Ps) and the change (Δ) of the measured position, so that the difference (δ) is added to the uncorrected position signal To obtain the corrected position signal and / or obtaining a corrected driving position value (V) by subtracting the difference value (δ) from the uncorrected driving position value (V0).

[0066] Obtaining the difference (δ) can be achieved in the position change acquisition module (8), as follows Figure 4 The difference (δ) between the reference change value (Δ0) calculated by the module (8) and the change (Δ) of the measured position is transmitted to the position correction module (5) so as to correct the position signal communicated to the processing device (1) for synchronous driving thereof at the driving point (Pi) based on the difference. and / or drive position value (V0; V).

[0067] According to this embodiment of the present invention, the position signal The correction of the and / or drive position value (V0; V) is achieved by applying directly (by addition or subtraction) to the uncorrected position signal and / or the difference (δ) of the uncorrected drive position value (V0), in addition to its simple implementation, it has the following advantages: since no additional mathematical operations other than addition or subtraction are required, the introduction of calculation errors in its processing is minimized.

[0068] The reference change value (Δ0) can be theoretically obtained, for example, by a theoretical function, in particular a kinematic function, which converts the uncorrected position signal The position change obtained in association with the displacement is related to the distance between the passing points (Pa, Ps). In particular, the same theoretical or kinematic functions can be used to calculate the uncorrected drive position value (Δ0) for the distance between the positioning point and the drive device (1), for example the drive point (Pi).

[0069] The reference change value (Δ0) and the uncorrected drive position value (V0) represent incremental position values ​​that, under ideal conditions of the system (no slip or deformation that would cause synchronization accuracy errors), correspond exactly to the distance between the points at which the positions are detected. In other words, for the reference change value (Δ0), it corresponds to the distance between the previous point (Pa) and the next point (Ps), and for the drive position value (V0), it corresponds to the distance between the positioning point (Pp) and the driving point (Pi). In this way, the synchronous drive method and system according to the present invention can capture errors to be corrected.

[0070] In the context of the present invention, the distance between points is generally understood to be the distance in the direction of displacement or along a straight or curved path of displacement. In this sense, generally, when it is indicated that there is no distance or no separation between two points, it is understood that their projections in the direction of displacement or along the displacement path coincide, or in particular that the points coincide with each other, i.e. they are the same point. In the embodiment shown in the drawings, the displacement direction is the direction indicated by the X-axis (see Figure 8 、 9 , 17 and 18).

[0071] Regarding the setting of the passing points (Pa, Ps), it can be imagined that, preferably, the previous passing point (Pa) is set to be basically close to or not far from the positioning point (Pp), and / or the subsequent passing point (Ps) or measuring point (Pm) is set to be basically close to or not far from the processing device (1; 1.1, 1.2, 1.3), in particular not far from the driving point (Pi).

[0072] Preferably, the previous passing point (Pa) is arranged after the positioning point (Pp), and / or the next passing point (Ps) is arranged before the processing device (1). In this way, each substrate (S) can be calibrated in real time after the reference element (R) of the substrate passes the next passing point (Ps) and before it is driven at the driving point (Pi).

[0073] In the context of the present invention, substantially close positioning, measuring, passing or driving points are understood to mean that the corresponding measuring devices, in particular detection sensors or processing devices, are arranged physically substantially adjacent along the displacement direction or path and / or the distance therebetween is substantially not greater than necessary so that due to the electronic processing limitations of the control device, there is time to transmit the corrected position signal to the reference element (R) of the substrate (S) after it passes the subsequent passing point (Ps). And / or the corrected drive position value (V) is applied to the processing device (1).

[0074] In this sense, reference Figure 5The distance (e) between the subsequent passing point (Ps) and the processing device (1), in particular the driving point (Pi), can be less than 10%, preferably less than 5%, and more preferably less than 1% of the distance (D) between the positioning point (Pp) and the processing device (1) or the driving point (Pi). Similarly, the distance (c) between the positioning point (Pp) and the previous passing point (Pa) can be less than 10%, preferably less than 5%, and more preferably less than 1% of the distance (D) between the positioning point (Pp) and the processing device (1) or the driving point (Pi).

[0075] The proximity of the preceding pass-through point to the positioning point and the proximity of the succeeding pass-through point to the driving point make it possible to maximize the distance (d) between the pass-through points (Pa, Ps) and, therefore, the synchronous error positioning length along the displacement, covering almost the entire displacement length of the substrate (S) from the positioning point to the driving point. Furthermore, the coincidence of these points makes it possible to use the same detection sensor for both.

[0076] exist Figure 6 In FIG, an embodiment is shown in which the previous passing point (Pa) is not far from the positioning point (Pp). Figure 7 , an embodiment is shown in which the preceding passing point (Pa) and the succeeding passing point (Ps) are not far apart. Figure 7 The embodiment shown can be applied, for example, to a system as shown in which a point of the belt (11) passes the same point (Pa, s) several times. In this sense, the present invention can be applied, for example, to a conveyor belt (10) as shown in the figure with a belt (11) displaced in a closed loop or a conveyor belt in which the belt itself moves forward and backward passing the same point.

[0077] Figure 8 and Figure 9 The system is shown in plan view in detail. These views show the specific arrangement and shape of the reference elements (R, Q, Q').

[0078] exist Figure 8 In the figure, a plate-like substrate (S) is shown having a reference element (R) incorporated on its upper surface; when the reference element (R) passes through a positioning point (Pp), a detection sensor (2) detects the reference element; when the reference element passes through a previous passing point (Pa), a detection sensor (2.1) detects the reference element; and when the reference element passes through a subsequent passing point (Ps), a detection sensor (2.2) detects the reference element.

[0079] For simplicity, the drawings illustrate that the reference element (R) used to detect its passage through the passing points (Pa, Ps) and the reference element used to detect its passage through the positioning point (Pp) are the same reference element (R). However, it is not excluded that these reference elements (R) may be different elements or may be arranged at different positions on the substrate (S).

[0080] Preferably, the substrate (S) and / or the conveying device (10, 11, 12), in particular the belt (11) of the conveyor belt (10), comprises a plurality of reference elements (R; Q, Q'). Thus, the greater the number of reference elements (R; Q, Q'), the more frequently a position signal can be corrected by obtaining different measured values, in particular positions, changes (Δ) or differences (δ) associated with a displacement. and / or drive position value (V0; V).

[0081] According to the invention, it is more preferably provided that the plurality of reference elements (Q; Q') are part of a reference pattern (Q, Q') fixed to the substrate (S) and / or the transport device (10), in particular to the belt (11). The arrangement of the reference elements (Q; Q') forming the reference pattern (Q, Q') allows to improve the reliability of the measurement by enabling a more precise control of the arrangement, size, distance, etc. of the reference elements constituting the pattern.

[0082] So, for example, in Figure 9 In the embodiment, the strip (11) incorporates a reference pattern (Q, Q'), which in this case consists of continuous black (Q) and white (Q') strips extending on one side of the strip (11) and along its entire length according to the length of the displacement on its upper surface. Reference elements (Q; Q') are lateral to each strip, in which the black and white colors change. The detection sensors (2.1, 2.2) are contrast detection sensors, which detect the change in black and white colors and thus detect the reference elements (Q; Q') when they pass through the passing points (Pa, Ps). The substrate (S) itself incorporates a reference element (R), which is detected by the detection sensor (2) when it passes the positioning point (Pp), as shown in FIG. Figure 8 As shown in the embodiment.

[0083] Reference elements and reference patterns suitable for use in the present invention may have any shape, configuration or arrangement. The reference elements (R, Q, Q') may be fixed, attached or integrated into the substrate (S) itself, in particular by forming part of the substrate or the conveying device (10), in particular in (on) the belt body (11) of the conveyor belt (10).

[0084] Specifically, the reference elements of the reference pattern can be formed of different patterns from each other, such as consecutive letters or numbers. Selecting different reference elements in the reference pattern makes it easier to distinguish between specific reference elements that have passed through the previous passing point (Pa) and then passed through the next passing point (Ps).

[0085] Likewise, in particular, there may be a plurality of reference pattern lines (Q; Q'), e.g. Figure 9The lines shown in , which are arranged parallel to each other, for example on each side of the strip, thus provide a large number of measurements per unit time.

[0086] Preferably, the method according to the invention comprises storing data associated with the measurement, for example in a control device memory. In particular, the method comprises storing positions, changes (Δ) and / or differences (δ) associated with the displacement for different substrates (S) and / or different reference elements (R; Q, Q') of the substrate (S) or the conveying device (10), so that a correction of the position signal is achieved based on the selection of said data, in particular by a FIFO method ("first in first out") and / or drive position value (V0; V). With the storage, the measured or acquired data can be managed regardless of the position of the substrate (S).

[0087] According to a preferred exemplary embodiment of the present invention, as shown in Figures 10 to 12, the uncorrected position signal and the corrected position signal is a pulse signal. In this case, the counting signal The position or position change (Δ) can be easily obtained by the number of pulses (p, p'). Directly obtained from the encoder, which encodes the position associated with the displacement. Advantageously, the position signal is processed into a pulse signal This allows it to be used as a clock signal for continuous synchronization of processing devices, as is done in digital printing.

[0088] Preferably, by using the uncorrected position signal Introducing or suppressing pulses (p, p') to obtain a corrected position signal This enables the position signal to be corrected in a simple manner

[0089] Therefore, for example, if the detected difference (δ) is δ=0 ( Figures 10a to 10b ), there is no need to Or any correction is made to the drive position value (V0), which means that the position change between the passing points (Pa, Ps) is ideal or expected.

[0090] Figure 10a represents the uncorrected pulse signal (p) obtained from the encoder (3) The signal period is T. The time when the reference element (R) passes the positioning point (Pp) is denoted as tp. The same figure shows the time when the reference element (R) passes the previous passing point (Pa). The dotted line represents the signal that has not yet passed.

[0091] Figure 10bIndicates a pulse signal At the time the reference element (R) passes the next passing point (Ps), which is denoted as ts. As can be seen, the value of the measured change (Δ) is Δ=2, since two pulses (p) were counted between ta and ts. Therefore, for a given reference change value (Δ0) of Δ0=2, this indicates that δ=Δ0–Δ=0, meaning that no pulses were inserted into the position signal or no correction was performed.

[0092] The driving of the processing means takes place for a given reference driving value, in this case V0=6, i.e. six pulses are counted starting from tp. The processing means (1) is driven at the driving point (Pi) at the instant Figure 10c It is represented as ti in Chinese.

[0093] and Figures 10a to 10c The example shown is similar to Figures 11a to 11c represents the case where the measured difference (δ) is δ=-1, so that by suppressing the corrected position signal The pulses (p) in the Therefore, since the driving position value is V0=6, the processing device (1) is later than Figures 10a to 10c The situation shown is driven at time ti, thereby delaying the execution of the action and thus increasing the synchronization accuracy.

[0094] and Figures 10a to 10c Similar to the examples shown in 11a to 11c, Figures 12a to 12c Indicates that the measured difference (δ) is δ = +1, so that by Add pulses (p) to modify the uncorrected position signal Therefore, since the driving position value is V0=6, the processing device (1) is earlier than Figures 10a to 10c The situation shown is driven at the time ti, so that the action performed is brought forward and thus the synchronization accuracy is increased.

[0095] The example explained with reference to Figures 10 to 12 is one in which the position signal is corrected based on the measured difference (δ) for a given drive position value V0. However, the present invention may also envision other exemplary embodiments, for example, correcting the driving position value (V0; V) by simply adding or subtracting the value of the measured difference (δ) from the driving position value (V0) without modifying the position signal

[0096] According to a preferred embodiment of the present invention, when the uncorrected position signal The position provided from the positioning point (Pp) takes the predetermined correction position value (V c ) when the position signal Specifically, the position value represents the time at which the pulses (p, p') required for correction are introduced or suppressed in the uncorrected position signal.

[0097] It is conceivable that the correction position value (V c ) is selected to be close to and / or smaller than the predetermined drive position value (V0). “Close” is understood to mean that the drive position value (V0) is close to the correction position value (V c ) is small compared to the drive position value (V0) but large enough to give a time-corrected position signal and / or drive position value (V0; V).

[0098] For example, as shown in FIG11 , the correction position value (V c ) is V c =5, this is due to the uncorrected position signal Five pulses are counted to suppress the corrected pulse (p). In the case shown in FIG12 , the corrected position value (V c ) is V c =3, this is due to the uncorrected position signal Three pulses of are counted to add the corrected pulse (p').

[0099] Figures 13 to 18 Different embodiments of the method and system according to the invention are shown, comprising a plurality of processing devices (1.1, 1.2, 1.3) with their respective driving points (Pi, Pi', Pi"; Pii, Piii).

[0100] Figure 17 and 18 A digital printer comprising a synchronous drive system is shown, wherein the processing device is a digital inkjet printing device (1.1, 1.2, 1.3). These digital printing devices are part of an inkjet printer (20), in particular a single-pass inkjet printer. Each digital printing device (1.1, 1.2, 1.3) comprises a plurality of print heads (21), each print head (21) having a plurality of ink nozzles (22), which are arranged to be aligned along a direction (Y axis) perpendicular to the displacement direction (X axis). It is conceivable that each digital printing device (1.1, 1.2, 1.3) corresponds to a printing color. The resolution of the print head (21) along the Y axis is determined by the distance (g) between the nozzles (22), so that Figure 18 In the configuration shown, the resolution is determined by half the distance between the nozzles (g).

[0101] exist Figures 13 to 15In the embodiment shown, the system comprises a plurality of consecutive processing devices (1.1, 1.2, 1.3) associated with a pair of passage points (Pa, Ps). This configuration makes it possible to optimize the measuring devices and the available space, in particular when it is not possible to insert detection sensors between the processing devices (1.1, 1.2, 1.3). According to a preferred embodiment, the processing devices (1.1, 1.2, 1.3) are arranged between the passage points (Pa, Ps).

[0102] exist Figure 13 and 14 In the first variant embodiment shown, the driving of the processing means (1.1, 1.2, 1.3) is achieved by jointly correcting the position signal and / or jointly correct the driving position value (V'). To this end, the system control device, in a manner similar to that of a system with only one processing device (1), comprises a position acquisition module (4), a position correction module (9) and a position change acquisition module (8). These modules (4, 8, 9) are operatively connected to each other, to a measuring device, in particular a detection sensor (2.5, 2.6), and to a processing device (1.1, 1.2, 1.3) to apply the synchronous driving method according to the present invention.

[0103] Position signal Common correction of the drive position values ​​(V0, V') can be achieved, for example, by nominal correction, such that the difference (δ) is applied in a distributed manner along the displacement length of the substrate as the substrate passes through the processing device. Specifically, the number of pulses per unit length is introduced or suppressed based on the value of the measured difference (δ) and the distance (f) between the pass-through points (Pa, Ps) and between the pass-through points and the processing devices (f1, f2, f3, f4). Similarly, common correction of the drive position values ​​(V0, V') can be achieved by nominal correction, such that the drive position value (V') is dynamically modified by applying the difference (δ) in a distributed manner along the displacement length of the substrate as the substrate passes through the processing device.

[0104] According to a preferred embodiment of the present invention, when the uncorrected position signal The position provided from the positioning point (Pp) takes the predetermined initial correction position value (V ci ) and until it takes the predetermined final correction position value (V cf ), for position signal And / or drive position value (V0; V') for rated correction. Specifically, the correction position value range (V ci , V cf ) denotes the time period during which the pulses (p, p') required for correction are introduced into or suppressed from the uncorrected position signal in a distributed manner.

[0105] exist Figure 14 and15 In the second variant embodiment shown, the processing means (1.1, 1.2, 1.3) are driven by the corresponding corrected position signals and / or the corresponding corrected drive position value (V A , V B , V C ) is achieved. To this end, the system control device, in a manner similar to that of a system with only one processing device (1), comprises a position acquisition module (4), a position correction module (9') and a position change acquisition module (8). These modules (4, 8, 9') are operatively connected to each other, to the measuring device, in particular the detection sensor (2.5, 2.6)) and to the processing device (1.1, 1.2, 1.3) to apply the synchronous driving method according to the present invention.

[0106] Position signal The correction can be achieved, for example, by weighted correction, such that the difference (δ) is applied in real time along the displacement length of the substrate as it passes through the processing devices (1.1, 1.2, 1.3), but in a weighted manner for each processing device (1.1, 1.2, 1.3). Specifically, a certain number of pulses is introduced or suppressed based on the value of the measured difference (δ) and the distance (f) between the passing points (Pa, Ps) and between the passing points and the processing devices (f1, f2, f3, f4).

[0107] According to Figure 16 According to another embodiment of the present invention, the system comprises a plurality of continuous processing devices (1.2, 1.3) associated with corresponding pairs of through points (Par, Ps'; Par, Ps"), wherein the preceding through point (Par) and / or the succeeding through point (Ps', Ps") are shared. Figure 16 In the variant embodiment shown, the preceding passage point (Par) corresponding to the last two processing devices (1.2, 1.3) is shared. This configuration makes it possible to optimize the measuring devices and the available space, while allowing the insertion of measuring devices, such as detection sensors (2.8, 2.9), between the processing devices (1.2, 1.3), in particular the passage points (Ps', Ps'), more specifically a single passage point.

[0108] The system control device comprises, in a manner similar to that of a system having only one processing device (1), a position acquisition module (4), corresponding position correction modules (5.1, 5.2, 5.3) and corresponding position change acquisition modules (8.1, 8.2). These modules (4, 5.1, 5.2, 5.3, 8.1, 8.2) are operatively connected to each other, to the measuring device, in particular the detection sensors (2.7, 2.8, 2.9) and to the processing device (1.1, 1.2, 1.3) to apply the synchronous driving method according to the present invention.

[0109] According to a preferred variant embodiment, the previous passing point (Pa; Par) is arranged substantially close to or not far from the previous processing device (1.1) compared to at least one processing device (1.2; 1.3), more specifically, it is arranged before the previous processing device (1.1). Figures 13 to 15 Examples and Figure 16 This is achieved in all embodiments because it is the preceding processing device (1.1), that is, it is arranged before the other processing devices (1.2, 1.3). Through this configuration, the driving of the subsequent processing devices (1.2, 1.3) relative to the preceding processing device (1.1) is achieved regardless of any synchronization errors that may affect the preceding processing device (1.1).

Claims

1. A method for synchronously driving at least one processing device (1, 1.1, 1.2, 1.3) for a substrate (S) displaced by a conveying device (10, 11, 12), comprising: - Obtain position signal through encoder (3) The signal provides a position associated with the displacement of the substrate (S) and / or the transport device (10, 11, 12) at each moment; as well as - driving the processing means (1) when said position from the positioning point (Pp) passed by said substrate (S) takes a given driving position value (V0); 1.1, 1.2, 1.3), the position is determined by the position signal supply; Characterized in that the method comprises: - measuring and / or acquiring data on displacement-related physical and / or motion characteristics of the substrate (S) and / or the transport device (10, 11, 12); and - Correction of the position signal based on the acquired measurements or data and / or the driving position value (V0; V; V'; V A , V B , V C ) to drive the processing device (1; 1.1, 1.2, 1.3).

2. The synchronous driving method according to the preceding claim, characterized in that: The method comprises: obtaining a position change (Δ) between a previous passing point (Pa; Par) and a subsequent passing point (Ps) by detecting a reference element (R; Q, Q') fixed to the substrate (S) and / or the transport device (10, 11, 12) passing through a passing point (Pa, Par; Ps), the position being determined by an uncorrected position signal Provided so that the position signal and / or the driving position value (V0; V; V'; V A , V B , V C ) is achieved based on the change (Δ).

3. The synchronous driving method according to claim 2, characterized in that: The method comprises obtaining the difference (δ; δ', δ") between the reference change value (Δ0) of the position between the passing points (Pa, Par; Ps) and the measured change (Δ) of the position, so that the corrected position signal By adding the difference (δ; δ', δ") to the uncorrected position signal and / or the corrected drive position value (V; V'; V A , V B , V C ) is obtained by subtracting the difference (δ; δ′, δ″) from the uncorrected drive position value (V0).

4. The synchronous driving method according to any one of claims 2 or 3, characterized in that: The substrate (S) and / or the transport device (10, 11, 12) comprises a plurality of reference elements (R; Q, Q'), in particular the reference elements (Q; Q') are part of a reference pattern (Q, Q').

5. The synchronous driving method according to any one of claims 2 to 4, characterized in that: The preceding passing point (Pa; Par) is arranged to be substantially close to or not far from the positioning point (Pp), and / or the succeeding passing point (Ps) is arranged to be substantially close to or not far from the processing device (1; 1.1, 1.2, 1.3).

6. The synchronous driving method according to any one of claims 2 to 5, characterized in that: The previous passing point (Pa; Par) is arranged after the positioning point (Pp) and / or the subsequent passing point (Ps) is arranged before the processing device (1; 1.1, 1.2, 1.3).

7. The synchronous driving method according to any one of claims 2 to 6, characterized in that: The previous passing point (Pa; Par) is arranged substantially close to or not far from the previous processing device (1.1) compared to at least one processing device (1.2; 1.3), more specifically, the previous passing point is arranged before the previous processing device (1.1).

8. The synchronous driving method according to any one of claims 2 to 7, characterized in that: A plurality of consecutive processing devices (1.1, 1.2, 1.3) are associated with a single pair of passing points (Pa, Ps) such that the processing devices (1.1, 1.2, 1.3) are connected to each other by a common corrected position signal and / or a common corrected drive position value (V') or by a corresponding corrected position signal and / or the corresponding corrected drive position value (V A , V B , V C ) is driven, in particular, the processing device (1.1, 1.2, 1.3) is arranged between the passing points (Pa, Ps).

9. The synchronous driving method according to any one of claims 2 to 7, characterized in that: A plurality of sequential processing devices (1.2, 1.3) are associated with corresponding pairs of passage points (Par, Ps'; Par, Ps"), wherein the preceding passage point (Par) and / or the succeeding passage point (Ps', Ps") are shared.

10. The synchronous driving method according to any one of the preceding claims, characterized in that The method comprises storing data associated with the measurement, in particular positions, changes (Δ) and / or differences (δ; δ', δ") associated with the displacement, for different substrates (S) and / or for different reference elements (R; Q, Q') of the substrate (S) or the transport device (10, 11, 12), so that the position signal and / or the driving position value (V0; V; V'; V A , V B , V C ) correction is based on the selection of the data, in particular by means of a FIFO method.

11. The synchronous driving method according to any one of the preceding claims, characterized in that The uncorrected position signal and the corrected position signal Is a pulse signal, especially through the counting signal The position, change (Δ) and / or difference (δ; δ', δ") associated with the displacement obtained by emitting a pulse (p, p') of 12. The synchronous driving method according to claim 11, characterized in that: By the uncorrected position signal The corrected position signal is obtained by introducing or suppressing pulses (p, p') in the 13. The synchronous driving method according to any one of the preceding claims, characterized in that The processing device (1; 1.1, 1.2, 1.3) is a digital inkjet printing device (1; 1.1, 1.2, 1.3), which is part of an inkjet printer (20), in particular a single-pass inkjet printer, each digital printing device (1.1, 1.2, 1.3) comprising a plurality of print heads (21), each print head (21) having a plurality of ink nozzles (22) aligned and arranged in a direction perpendicular to the displacement, in particular the digital printing device (1.1, 1.2, 1.3) is constructed to eject droplets with a volume less than or equal to 20 pL, preferably 10 pL, more preferably 5 pL, and / or provide a printing resolution greater than or equal to 360 dpi, preferably 720 dpi, more preferably 1200 dpi in a direction perpendicular to the displacement.

14. A synchronous drive system for at least one processing device (1; 1.1, 1.2, 1.3) for a substrate (S), wherein: The substrate is moved relative to the device (1; 1.1, 1.2, 1.3) shift, characterized in that the system is configured to perform the synchronous driving method according to any one of the preceding claims, comprising: - a device for measuring and / or acquiring data on displacement-related physical and / or movement characteristics of the substrate (S) and / or the conveying device (10, 11, 12), in particular comprising at least one detection sensor (2; 2.1, 2.2; 2.3; 2.4; 2.5, 2.6; 2.7, 2.8, 2.9) for detecting the passage of a reference element (R; Q; Q') fixed to the substrate (S) and / or to the conveying device (10, 11, 12); a measuring sensor (7), in particular a speed sensor, for the substrate (S) and / or for the conveying device (10, 11, 12); and / or a data logger (6); and - a control device (4, 5, 8, 9, 9'; 5.1-5.3; 8.1, 8.2) operatively connected to the encoder (3) to acquire a position signal connected to means for detecting the passage of the substrate (S) through a positioning point (Pp), to means for measuring and / or acquiring data on physical and / or movement characteristics of the substrate (S) and / or the transport device (10, 11, 12) related to the displacement, and to the processing device (1; 1.1, 1.2, 1.3).

15. A digital printer for a substrate (S), comprising: - an inkjet printer (20), in particular a single-pass inkjet printer, comprising a plurality of digital printing devices (1.1, 1.2, 1.3); - a transport device (10, 11, 12) for displacing a substrate (S) to be printed by the inkjet printer (20); - Encoder (3) for acquiring position signals The position signal provides a position associated with the displacement of the substrate (S) and / or the transport device (10, 11, 12) at each moment; as well as - means for detecting the passage of the substrate (S) through a positioning point (Pp), comprising in particular a detection sensor (2) for detecting the passage of a reference element (R) fixed to the substrate (S) through the positioning point (Pp); Characterized in that the digital printer comprises a synchronous drive system according to the preceding claim for synchronously driving the digital printing device (1.1, 1.2, 1.3) of the substrate (S) when the substrate (S) is displaced by the transport device (10, 11, 12).

Images