Abstract:
An apparatus and method for controlling at least one of a position or at least one dimension of printed products conveyed while positioned flat in a conveyed flow. A conveying device transports the printed products and at least one sensor is directed toward an edge of the printed products and comprises a line sensor or area sensor. A computer-supported control is coupled to receive an output signal of the at least one sensor.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority of European Patent Application No. 07405253.1, filed on Aug. 28, 2007, the subject matter of which is incorporated herein by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to an apparatus for controlling the position and/or at least one dimension of printed products, which are conveyed while positioned flat in a conveyed flow and are composed of several signatures or individual printed sheets, with the aid of a conveying device for transporting the printed products and at least one sensor that is directed toward the printed products and is connected to a computer-supported control. 
         [0003]    For the processing of printed products, it is frequently necessary to detect the position of the printed products to be processed, for example inside a cutting machine. Deviations from a predetermined position can cause the printed product to differ impermissibly from the specified dimensions and/or an angle. It should furthermore be possible to check the length, width, or thickness of printed products without influencing the production speed. 
         [0004]    Japanese patent document JP 2005-62127A discloses an apparatus in which printed products are supplied with the aid of a conveying device to an angular measuring frame. Several sensors are used to respectively check whether the printed product supplied to the measuring frame exceeds or falls below a predetermined width or length. It can furthermore be checked whether the printed product is right-angled. Printed products which do not have the predetermined dimensions can thus be transferred out. However, this apparatus is not suitable for high capacity processing and larger series, since the individual printed products must be stopped at the measuring frame and must then be accelerated once more. 
         [0005]    German patent document DE 102 47 455 A discloses an apparatus for adjusting the position of the side edges of a continuous web, wherein sensors are provided for detecting the desired position of the side edges. However, this apparatus is not suitable for processing individual printed products, such as is the case for gathering and wire-stitching machines. 
       SUMMARY OF THE INVENTION 
       [0006]    It is therefore an object of the present invention to create an apparatus of the aforementioned type, which ensures a high quality of the printed products to be processed and which is furthermore suitable for use with larger series. 
         [0007]    The above and other objects are achieved according to an embodiment of the invention wherein there is provided an apparatus for controlling at least one of a position or at least one dimension of printed products conveyed while positioned flat in a conveyed flow, the apparatus comprising: a conveying device to transport the printed products; at least one sensor directed toward an edge of the printed products and comprising one of a line sensor or area sensor; and a computer-supported control coupled to receive an output signal of the at least one sensor. 
         [0008]    Such an apparatus not only permits the detection of the printed products at one point, as has been the case so far, but allows the detection over a region. In particular, a line-shaped region of the printed products is detected transverse to one edge of the printed products. As a result, it is not only possible to detect the position of the corresponding edge, but also to measure the edge relative to its position. Measurements of this type in particular make it possible to control a drive, for example for adjusting a position. Suitable line sensors and area sensors are already known and, in particular, allow an analog detection of the position of a product edge. 
         [0009]    The detection of the printed products with the sensor preferably occurs while the products are transported in a horizontal plane with a conveying device. In principle, the printed products can also be detected by the sensor in a different position, for example while in a plane that is slanted transverse to the conveying direction or while in a suspended position. 
         [0010]    Two or more sensors can also be used in place of a single sensor to simultaneously detect a printed product. For example, opposite-arranged edges of a printed product can be detected with two sensors, thus making it possible to check the course of these two edges and, in particular, check whether the edges are parallel to each other. In addition, a spacing between these two edges, that corresponds to either the length or the width of a printed product, can be determined. If the sensors are arranged to be displaceable, it is possible to detect and/or measure printed products belonging to a broad format range. 
         [0011]    The sensor is preferably an optical sensor, wherein non-optical sensors, such as electronic sensors, are conceivable as well. US 2003/0072499 A1 and US 2005/0239621 A1 disclose suitable optical sensors while electronic sensors are disclosed in DE 19941728 A1 and are commercially available as ZADM 034 at Baumer Ltd. 
         [0012]    According to a modified embodiment of the invention, the leading edge of a printed product is detected with the sensor, thus making it possible to control the position of the printed products, for example for the trimming of the trailing edge inside a cutting apparatus. The sensor in particular is used to detect the position of the printed product and control the drive for the conveying device based on the direct measurement taken at the printed product. This permits an especially precise positioning of the printed products for a processing, for example, for the step of cutting, punching, addressing, gluing and the like. 
         [0013]    The apparatus is particularly suitable for use with a gathering and wire-stitching machine, an inserting machine, a perfect binder or a collating machine. However, the apparatus can conceivably also be used with other machines for processing printed products, for example machines for producing newspapers, magazines, books, booklets and the like. 
         [0014]    According to another aspect of the invention there is provided a method for controlling at least one of a position or at least one dimension of printed products conveyed while positioned flat in a conveyed flow, the method comprising: transporting the printed products with a conveying device; directing at least one line sensor or area sensor toward the printed products to sense an edge of a respective one of the printed products to produce an output signal corresponding to said edge; and outputting the output signal to a computer-supported control. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    These and other features and advantages of the invention will be further understood from the following detailed description with reference to the accompanying drawings, which show in: 
           [0016]      FIG. 1   a  A diagrammatic view from the side of an apparatus according to the invention for trimming printed products; 
           [0017]      FIG. 1   b  A diagrammatic view from above of the apparatus according to  FIG. 1   a;    
           [0018]      FIG. 2   a  A diagrammatic view from the side of an apparatus according to the invention; 
           [0019]      FIG. 2   b  A diagrammatic view from above of the apparatus according to  FIG. 2   a;    
           [0020]      FIG. 2   c  A different diagrammatic view from above of a variant of the apparatus according to  FIGS. 2   a  and  2   b;    
           [0021]      FIG. 3   a  A diagrammatic view from above in the conveying direction of a variant of the apparatus according to the invention; 
           [0022]      FIG. 3   b  A diagrammatic view from above of the apparatus according to  FIG. 3   a;    
           [0023]      FIG. 4   a  A diagrammatic view from the side of a variant of the apparatus according to the invention; 
           [0024]      FIG. 4   b  A diagrammatic view from above in the conveying direction of the apparatus shown in  FIG. 4   a.    
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Referring to  FIGS. 1   a  and  1   b , there is shown an apparatus  1  which comprises a conveying device  13  for transporting printed products  6  inside a cutting machine  7  in a conveying direction  22 . The conveying device  13  is operated with a drive  5  and is provided with at least one endless conveying belt or a toothed belt for transporting the printed products  6 . In place of the endless conveying belt, the conveying device  13  can also be provided with different, suitable transporting elements such as grippers that convey the gripped printed products  6  while these are positioned horizontally. The printed products  6  can be signatures or individual printed sheets, which can be joined by gluing or stitching. The printed products  6  are conveyed, as shown in  FIGS. 1   a  and  1   b , by a feed apparatus  19  in a conveying direction  21  and are preferably transferred while spaced-apart to the conveying device  13 . The feed apparatus  19  is operated by a drive, not shown herein, which can also operate other devices in addition to the feed apparatus  19 . The printed products  6  are stopped at least once in the apparatus  1  to carry out a processing step, for example the cutting or trimming of at least one of the edges  9 ,  10 , meaning along the respective side edges and/or the respectively trailing edge. In the process, a section  17  of the stationary printed product  6  is cut off while the product is positioned between an up- and down moving upper blade  15  and a stationary lower blade  16  in order to obtain the desired width  30  for the printed products  6 . To avoid a displacement of the printed products  6  during the delay and/or the acceleration, the conveying device  13  can be embodied such that the printed products  6  are at least partially clamped in, for example between a lower and an upper conveying belt. In a further processing step, holes can be punched into the stationary printed products  6 . The leading edges  8  of the printed products  6  that are positioned flat must always be positioned precisely, so that the width  30  of successive printed products  6  is within the tolerance range of ±0.02 to ±1 mm. 
         [0026]    Two spaced-apart sensors  2 , which can be embodied identically, are arranged above the conveying device  13 . These sensors  2  are so-called line sensors or also area sensors, which may be light-sensitive and extend over a predetermined length. In this case, the sensors extend parallel to the transporting direction  22  for the conveying device  13 , which forms a component of the cutting machine  7 . The two sensors  2  are arranged in so that they can simultaneously detect the respective leading edge  8  of a printed product  6 . Since the sensors  2  extend over a specific length in the conveying direction  22 , all positions of the leading edge  8  can be detected within this section. 
         [0027]    In addition to the printed product  6 ,  FIG. 1   b  also shows the printed products  6 ′,  6 ″ with the leading edges  8 ′,  8 ″ and the side edges  9 ′,  9 ″, which respectively occupy during the processing a position that differs from the position of the printed product  6 . The two sensors  2  respectively form a light curtain  2   b , which in part impinges on the top of the respective printed product  6 ,  6 ′,  6 ″ and in part also on a reflector  2   a . The light rays impinging on the reflector  2   a  are reflected back to the sensor  2 . As a result, it is possible to determine at any time which region of the respective printed product  6 ,  6 ′,  6 ″ is located within the area covered by the two sensors  2 . Each position of the leading edges  8 ,  8 ′,  8 ″ and thus also the position of the printed products  6 ,  6 ′,  6 ″ can therefore be detected in the area that is covered by the length of the two sensors  2 . 
         [0028]    The measuring values are supplied via corresponding signals to an automatic controller  3 . This automatic controller  3  is connected to a control  4  and the drive  5 . The conveying device  13 , the two sensors  2 , the automatic controller  3  and the drive  5  jointly form a control loop, which makes it possible to precisely control the transport of the respective printed products  6 ,  6 ′,  6 ″. 
         [0029]    In the event that a deviating position of a printed product  6 ′,  6 ″ is not or only insufficiently corrected by the conveying device  13 , the dimensions for the printed products  6 ′,  6 ″ can differ from the desired value as a result of the cut made to the trailing edge  10 . For example, the width  30  can be either too small or too large and/or the leading edge  8  and the trailing edge  10  are not parallel to each other. Printed products  6 ′,  6 ″ of this type can be removed from the conveyed flow, for example with the aid of a diverter  18  that is connected to the control  4  and is positioned downstream of the conveying device  13 . As a result, it is ensured that only printed products  6  that are within a selectable tolerance range during the processing are transferred to a downstream arranged transporting apparatus  20  and are conveyed further in a transporting direction  23 . 
         [0030]    The sensors  2  alternatively can also be used detect the trailing edge  10 ,  10 ′,  10 ″ of the printed products  6 ,  6 ′,  6 ″, wherein it is additionally possible to detect the leading edge  8 ,  8 ′,  8 ″ as well as the trailing edge  10 ,  10 ′  10 ″. 
         [0031]      FIGS. 2   a ,  2   b  and  2   c  each illustrate an apparatus  1 ′ provided with the above-mentioned conveying device  13  for successively transporting the spaced-apart printed products  6  one after another in a conveyed flow in a transporting direction  11 . 
         [0032]    The conveying device  13  has a separate drive that is not shown herein, or it is drive-connected to an upstream or downstream arranged apparatus. It is furthermore possible to use a controlled drive  5 , which is described in the above but not shown herein and is connected via the automatic controller  3  to the control  4 . According to  FIG. 2   a , at least two sensors  2  are arranged successively in the transporting direction  11 , so that the leading edge  8  and the trailing edge  10  of a printed product  6  can be detected simultaneously. Particularly advantageous is the arrangement of four sensors  2 , wherein respectively two sensors  2 , spaced apart on the side, detect the leading edge  8  and two sensors  2 , arranged behind them in transporting direction  11 , detect the trailing edge  10 . Based on the signals received from the sensors  2 , the control  4  can determine the position and/or the dimensions of the printed products  6  while these are passing through or while these are stopped. The signals from the sensors  2  are sufficient to realize a comparison measurement for which the printed products  6  are compared to a previously input and/or read-in value. If the width  30  for each individual printed product  6  is to be determined, the distance  31  between the two successively following sensors  2  in transporting direction  11 , as well as the signals from the sensors  2 , must be input into the control  4 . 
         [0033]    The apparatus  1 ′ makes it possible to determine the width  30  of the printed products  6 ,  6 ′, regardless of whether the products are aligned correctly, are displaced to the side, or are positioned at a slant. It is furthermore possible to check whether the leading edge  8 ,  8 ′ and the trailing edge  10 ,  10 ′ are aligned parallel to each other. With the aid of a device for transferring out printed products  6 , e.g. a diverter  18  that follows the apparatus  1 ′ and is connected to the control  4 , it is possible to transfer out the printed products for which the position and/or width  30  and/or the parallel positioning of the edges  8 ,  8 ′,  10 ,  10 ′ is outside of the selected tolerance range. 
         [0034]    The sensors  2  can be arranged to be displaceable, so that it is possible to detect the leading and/or the trailing edges  8 ,  10  of the printed products  6  having very different widths  30  by changing the spacing  31  between the sensors  2  that follow each other in the transporting direction  11 . 
         [0035]      FIG. 2   c  shows two alternative sensors  2 ′, which are longer in longitudinal direction than the width  30  of the printed products  6  to be processed. The arrangement of the sensors  2 ′ according to  FIG. 2   c  makes it possible to check the above-described quality features using only two sensors  2 ′ instead of the four sensors  2  as shown in  FIG. 2   b.    
         [0036]    The apparatus  1 ″ illustrated in  FIGS. 3   a  and  3   b  is also provided with a conveying device  13  as mentioned in the above for conveying the printed products  6 ,  6 ′ successively in a transporting direction  12 . Two sensors  2 ″, which can be embodied identically in the same way as the aforementioned sensors  2 ,  2 ′, in this case are arranged so as to extend transverse to the transporting direction  12  and across the side edges  9 ,  9 ′ of the printed products  6 ,  6 ′. The light rays of a light curtain  2   b ″ that forms, which impinge on the reflectors  2   a ″, are reflected back to the two sensors  2 ″. As a result of the sensors  2 ″ extending on the side and the resulting reflection, the position of the respective side edges  9 ,  9 ′ and thus also the length  32  of the printed products  6 ,  6 ′ can be detected and/or measured. 
         [0037]      FIG. 3   b  shows the detection of the printed products  6  with the aid of the two sensors  2 ″, wherein the sensors  2 ″ can detect the complete length of the side edges  9 . As a result, it is also possible to detect deviations from the parallel positioning of the side edges  9 , a displacement in conveying direction or transverse thereto, as well as a slanted position of the printed product  6 . For example, if the side edges  9 ′ of a printed product  6 ′ extend at a slant to the transporting direction  12 , this deviation and/or the course of the side edges  9 ′ can be detected and/or measured with the sensors  2 ′. For example, if the deviation of the printed product  6 ′ exceeds the specified tolerance range, the printed product can be aligned with the aid of a positioning device  33  or, alternatively, can also be transferred out. 
         [0038]    Defective printed products are transferred out, for example, with the aid of a diverter  18  as shown in  FIGS. 1   a  and  2   a , which is controlled by a control  4  that is connected to the sensors  2 . Also conceivable is an embodiment where only one of the side edges  9  is detected with a sensor  2  or which comprises more than two sensors, for example 4 sensors. More than two edges of a printed product  6  can be detected simultaneously when using a plurality of sensors  2 ,  2 ′,  2 ′ of this type. For example, a leading edge  8  and/or a trailing edge  10  can also be detected in addition to the side edges  9 . 
         [0039]    In the apparatus  1 ′″ shown in  FIGS. 4   a  and  4   b , the printed products  6  are conveyed while spaced apart by carriers  29  on a conveying device  28 , such that they move along a support  27  in a transporting direction  24 . One side edge  9  of the printed products  6  that are positioned flat follows the support  27  and positions the printed products  6  transverse to the transporting direction  24 . The printed products  6  that are conveyed inside a slanted channel  26  for an inserting and/or collating machine, for example, rest against the support  27 . The course of the side edge  9  of the printed product  6 , which is located opposite the side edge  9  that rests against the support  27 , is detected with the aid of at least one sensor  2 ″ that is positioned transverse to the transporting direction  24  and is directed towards this side edge  9 . The printed products  6  therefore cover at least a portion of the reflector  2   a ″ that is mounted underneath the transporting plane. The sensor  2 ″ forms a signal with the light rays of the light curtain  2   b ″, which are reflected back to the sensor  2 ″ in the exposed region of the reflector  2   a ″, wherein this signal is evaluated in the control  4 . If the format range for the printed products  6  is large, relative to the length of the sensor  2 ″, then the sensor  2 ″ can be embodied so as to be displaceable transverse to the conveying direction in order to achieve that the side edge  9  to be measured comes to rest within the light curtain  2   b″.    
         [0040]    In the process, the reflector  2   a ″ is either displaced together with the sensor  2 ″, or is embodied such that it covers the complete adjustment range for the sensor  2 ″ as a result of its extension in the adjustment direction of the sensor  2 ′. 
         [0041]    The advantage of the invention therefore is that the position and location of the printed products  6  can be detected precisely and in particular that their dimensions can be determined, thus making it possible to control and adjust the position and location. Critical processing steps such as the cutting or stitching operations in a gathering and wire-stitching machine can thus be realized with more precision and reliability. As a result, control operations on printed products  6  that pass through or stand still can be carried more reliably and with higher efficiency, so that defective printed products  6  can be transferred out. Finally, it allows the production of higher quality printed products  6 , for example books, booklets and the like, without reducing the capacity of presently used systems and apparatuses. 
         [0042]    It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.