Abstract:
A method of monitoring the transport of flat copies along transport paths in a folder includes selecting sensors for detecting at least one of the presence and the absence of copies, depending upon the folding mode of the folder; determining by transmitters the number of copies that have entered the folder, and comparing the number of copies present in the folder with the number of copies detected by the sensors; a device for performing the method; a folder including the device; and a rotary printing machine in combination with the folder.

Description:
BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The invention relates to a method and a device for monitoring the transport of flat copies, for example copies separated from a material web in a folder and to be folded longitudinally and/or transversely therein. 
     The published European Patent Document EP 0 847 857 A1 is concerned with an adjusting device of a traversing mechanism disposed upline of a cylinder in a rotary printing machine. On the traversing mechanism, a measuring device is displaceable axially with respect to the circumferential surface of the cylinder by a holder. For adjusting the alignment of the traversing mechanism with respect to the cylinder in a manner that is accurate, uncomplicated and can be automated and has an interchangeable direction of adjustment, the holder can be coupled to an opto-electric auxiliary adjustment device. The auxiliary adjustment device has an optical element that projects a light beam onto the cylinder and at least one optical receiver, which receives a light beam reflected from the cylinder. The optical receiver includes an opto-electronic sensor which, in conjunction with evaluation electronics, is suitable for detecting the position of the reflected light beam on the sensor. 
     This device is primarily used to align an optical measuring device that scans the surface of the cylinder. 
     The European Patent 0 753 409 is concerned with a sheet printing machine having a delivery on the upper side of which continuously delivered sheets are to be deposited. It is intended to make possible, in a manner which is simple and does not adversely affect the formation of a sheet pile, the use of a traversing measuring device for scanning a printing control strip applied to the leading edge of the sheets. For this purpose, the measuring device, which is movable on a traversing mechanism, has so-called sheet high-holders assigned thereto, which prevent sheets conveyed while a measuring operation is being performed from being deposited on the upper side of the stack. 
     With this device from the prior state of the art, however, a conveying path traced by the copies, somewhat through a folder, cannot be detected reliably. 
     U.S. Pat. No. 3,815,895 discloses a paper-jam detection system for folders which are arranged downline of a web-fed rotary printing system. Photocells disposed within the folder at selected locations detect both copies which are erroneously absent and copies which are erroneously present along the conveying path through the folders. A time-sequence control unit, which operates in synchronism with the folder, generates signals which initiate detection as to whether a copy to be expected at a specific location is actually present there and whether a copy not to be expected at a specific location on the conveying path actually does not arrive at this location. The signals from the photocells are logically linked with those from the time-sequence control unit, and fed to a logic circuit which, if necessary or desirable, stops the folder. The system also detects a failure of one of the photocells in the paper-jam detection system. 
     It has been found that not only paper jams which occur at full operating speed in a web-fed rotary system cause drastic consequences in the folder and long down times of a rotary printing machine, but also, paper jams which occur even during the threading of the web or at creep speed of the rotary printing machine, or due to misguiding the paper can at least cause avoidable delays during run-up or acceleration of the rotary printing machine. During the threading of the web or at creep speed of the rotary printing machine, very high torques can occur, mechanical settings of grippers, cylinders or similar components in relation to one another can be indefinite, while the attention of the pressman can be directed to other work necessary within the context of a new job set-up. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the inventions to provide, in accordance with the invention and in view of the outlined advancements in the prior art and the indicated technical problems, a device for monitoring the transport of flat copies or, in other words, a paper-run monitoring system, which is responsive to irregularities in the copy transport at slow paper conveyance speeds. 
     With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a method of monitoring the transport of flat copies along transport paths in a folder, which comprises selecting sensors for detecting at least one of the presence and the absence of copies, depending upon the folding mode of the folder; determining by transmitters the number of copies that have entered the folder, and comparing the number of copies present in the folder with the number of copies detected by the sensors. 
     In accordance with another mode, the method of the invention includes validating the sensors based upon the progression of the copies along the transport paths, in accordance with the folding mode of the folder. 
     In accordance with a further mode, the method of the invention includes performing a validation, at the start of the transport of the copies through the folder, by sensors upland to the transport start, after a few copies have been conveyed to the folder. 
     In accordance with an added mode, the method of the invention includes performing a validation of sensors disposed farther downline along the transport path than the first-mentioned sensors, after a large number of copies have been transported into the folder. 
     In accordance with an additional mode, the method of the invention includes assigning a transmitter to a cylinder, and determining by the transmitter the number of copies transported into the folder. 
     In accordance with yet another mode, the method of the invention includes determining the number of copies transported into the folder, by a transmitter assigned to a drive of the folder. 
     In accordance with yet a further mode, the method of the invention includes transmitting the determined number of copies to a monitoring and evaluation unit. 
     In accordance with yet an added mode, the method of the invention includes, in accordance with a selected folding mode of the folder, determining for each sensor the ratio between the number of copies that have entered the folder and the number of copies respectively counted at the sensor position. 
     In accordance with yet an additional mode, the method of the invention includes, for each sensor position, determining a maximum permissible difference between the number of copies that have entered the folder and the number of copies that have actually appeared at the position of the respective sensor. 
     In accordance with still another mode, the method of the invention includes performing the validation of the respective sensors based upon the attainment of a minimum number of conveyed copies at the respective position of the sensors. 
     In accordance with still a further mode, the method of the invention includes performing the comparison between the theoretical number of copies and the number of copies actually detected for each sensor position in real time. 
     In accordance with another aspect of the invention, there is provided a device for performing a method of monitoring the transport of flat copies along transport paths in a folder, comprising sensors grouped as sensor pairs, respectively, having a transmitting part and a receiving part. 
     In accordance with another feature of the device of the invention, at least one of the material web and the copies are conveyable in a conveying plane, and the receiving and transmitting parts of the sensors are arranged on opposite sides of the conveying plane. 
     In accordance with a further feature of the device of the invention, the transmitting part is formed as a proximity switch. 
     In accordance with an added feature of the invention, the device includes a transmitter assigned to a drive of the folder and formed as a rotary encoder. 
     In accordance with an additional feature of the device of the invention, a then current folding mode of the folder is determinable by the position of the folding components on a paper-carrying cylinder, and further included is a monitoring unit to which the then current folding mode is transmittable. 
     In accordance with another aspect of the invention, there is provided a folder for a rotary printing machine, for processing material webs, the folder being capable of operating in at least two folding modes, and having its own drive, comprising a monitoring unit, by which, in accordance with a respectively selected folding mode, copy conveying paths are able to be validated by respective sensors assigned to the copy conveying paths, based upon progressions of the copies through the folder, and the number of the copies present in the folder are able to be compared with the number of copies that have entered the folder. 
     In accordance with a concomitant aspect of the invention, there is provided a rotary printing machine having a folder that is capable of operating in at least two folding modes, and having its own drive, comprising a monitoring unit, by which, in accordance with a respectively selected folding mode, copy conveying paths are able to be validated by respective sensors assigned to the copy conveying paths, based upon progressions of the copies through the folder, and the number of the copies present in the folder are able to be compared with the number of copies that have entered the folder. 
     The advantages that can be achieved by the foregoing modes and features of the invention are many and varied. Thus, by using the method according to the invention, folders can be incorporated significantly faster into the paper run at creep speed of the upline rotary printing machine, because misrouted copies in the folder can be detected immediately and can lead to the folder drive being switched off. This constitutes an effective safeguard for mechanical folding components which are installed in an, as yet, undefined way in relation to one another and which, at creep speed, could be considerably damaged by the high torques occurring thereat. Both at creep speed of the rotary system and also during the paper threading phase, the pressmen can devote their attention to further necessary pre-settings, an incipient paper jam or the misrouting of a copy will then be detected automatically. 
     In a further refinement of the method upon which the invention is based, sensors in the folder are validated, based upon the progression of the copies along the conveying path, depending upon the folding mode of the folder. The validation, i.e., the declaration of validity of a sensor signal, which can be performed electronically, in the case of the sensors located at the start of the copy conveying path, is carried out only after a few copies have entered the folder, after which the relevant sensor can detect a copy at the very earliest, in accordance with the folding mode set with the preselected transport path. The validation of sensors arranged earlier in the copy transport path is carried out after a lower, pre-settable number of copies, while the validation of sensors arranged later in the copy transport path is carried out after a larger number of copies have entered the folder, corresponding to the distance extending as far as the validating sensor. 
     The limiting values which permit the validation can be predefined at the monitoring unit and stored there, so that they are always currently available for the necessary calculations. 
     The validation of the sensors corresponding to the selected folding mode along the conveying path of the copies that is associated with the folding mode ensures the reliability of the signals transmitted by the sensors to the monitoring unit. The determination of the number of copies which have entered the folder is carried out, for example, by transmitters assigned to the cutting cylinders or revolution counters assigned to the drive motor of the folder. Depending upon the selected length of the cut, it is thus possible for the number of copies transported into the folder to be determined individually. 
     In the monitoring unit, according to the method of the invention, the difference between the number of copies detected for each validated sensor and the number of copies located in the folder is determined continuously, it being possible for a maximum permissible difference to be predefined at the monitoring unit. This difference can be predefined in accordance with or based upon the printing material parameters, copy thickness and values from experience, in order to set up the monitoring system suitably for the job. 
     The sensors required in order to perform the method according to the invention are preferably pairs of sensors which comprise a transmitting and a receiving part. These are spaced apart from one another, with the conveying path of the copies running between the transmitting and receiving parts. The transmitters assigned to the cutting cylinders or the drive of the folder can be configured, for example, as proximity switches or encoders, such as rotary encoders, which for each revolution of the relevant unit transmit a counting pulse to the monitoring unit, the pulses being added therein. 
     By the modes and features of the invention, it is preferably possible to monitor folders which are arranged downline of a web-fed rotary printing machine, the monitoring unit validating the sensors required in accordance with the copy conveying path necessary for the selected folding mode, and the sensor signals, validated in this way, for the number of copies being compared with that number which has entered the folder. From this comparison, performed in real time, a switch-off condition in the folder and/or for the entire rotary printing machine can be derived. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a method and device for monitoring the transport of flat copies, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
    
    
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic view showing the basic construction of a folder with pairs of sensors assigned to the respective copy conveying path; 
     FIG. 2 is a view like that of FIG. 1 showing copy being conveyed through the folder in a manner corresponding to that of the double parallel folding mode; 
     FIG. 3 is another view like that of FIG. 1 showing copy transport through the folder in a manner corresponding to that of the second longitudinal folding mode, with a dividing copy stream; and 
     FIG. 4 is a basic flow chart reproduced in relatively simplified form and clarifying the mode of operation of the control unit. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and, first, particularly to FIG. 1 thereof, there is illustrated therein the basic construction of a folder with pairs of sensors assigned to the respective copy delivery paths. 
     A material web  15 , which can also be formed of a number of layers of material web, after passing through a turner-bar superstructure not otherwise specifically illustrated in the drawings, enters the folder  30 , having already been provided with a first longitudinal fold. The presence of the material web  15  is detected by a pair of sensors  1 , which include a transmitting and a receiving part  1   a  and  1   b , respectively. The material web  15  transported in the conveying plane  16  passes through a cutting-cylinder pair  2   b ,  17  including a cutting cylinder  2   b  and a grooved cylinder  17  cooperating therewith. The individual copies are separated thereat from the material web  15  by cross-cutting the latter. 
     The cutting cylinder  2   b  can optionally have a transmitter  2   a  assigned thereto which, for each revolution of the cutting cylinder  2   b , transmits a counting pulse to a monitoring unit  12 . For each revolution of the cutting cylinder  2   b , precisely one copy is separated from the leading end of the material web  15 , as a result of which the number of copies present in the folder  30  can easily be determined. Alternatively, the number of copies which have entered the folder  30  can be determined via a rotary encoder  14 , which registers the revolutions of the drive motor  13  that drives the folder  30 , based upon which, likewise the number of copies that have entered the folder can be determined. The values for the copies entering the folder which are obtained in this manner are determined continuously and stored in the monitoring unit  12 . 
     The further transport of the copies is then monitored by a pair of sensors  3  assigned to a folding-blade cylinder  18 . The folding-jaw cylinder  19  operates together with the folding-blade cylinder  18 , the first crossfold on the copy being formed between these two cooperating cylinders  18  and  19 . The folding-jaw cylinder  19  has two further transport or gripper cylinders  20  and  21  assigned thereto which, on the one hand, form a further crossfold in the copy and, on the other hand, alternately pick up the copies from the circumference of the folding-jaw cylinder  19  and, in this way, effect the division of the copy stream. 
     Downline of the upper transport cylinder  20 , there extends an upper conveying path  22 , safeguarded by a pair of sensors  4 , which continues to an upper second longitudinal folding device  10   b.  In a manner analogous thereto, a lower conveying path  23  is assigned to the lower transport cylinder  21 , likewise safeguarded by a pair of sensors  5 , the copies being fed via a lower conveying path  23  to a further second longitudinal folding device  10   a . The two second longitudinal folding devices  10   a  and  10   b , respectively, include a respective folding blade  27 , which forms the folded spine on the copy by pushing it in between folding rollers, otherwise not specifically illustrated in the drawings. The double circles located above the respective folding blades  27  are supposed to indicate the drive to the folding blades  27  in simplified form. 
     Connected downline of the upper second longitudinal folding module  10   b  is a paddle-wheel configuration  25 ,  26 , it being possible both for each paddle wheel  25  and  26  to monitor the entry of the copies by respective sensor pairs  7  and  6 , and also to monitor the copies leaving the paddle wheels  25  and  26  by sensor pairs  8  and  9 , respectively. At the outlet  11 , the copies, laid out in imbricated or overlapping formation, leave the folder  30  in order to be fed to a stacker or a packaging machine for further processing. 
     FIG. 2 shows copy transport through the folder corresponding to the double parallel folding mode. 
     The conveying path  28  reproduced in FIG. 2 with a very bold line thickness indicates the transport path which the copies, separated from the material web  15  by the cutting-cylinder pair  2 b,  17 , assume in the double parallel folding mode. In this operating mode of the folder  30 , the copies are double-parallel folded by the mutually cooperating folding cylinders  18 ,  19  and  20 . The copies are conveyed along the upper conveying path  22 , the upper second longitudinal folding device lob being inactive and permitting the crossfolded copies to pass. The latter can then be routed optionally into a lower paddle wheel  26  or an upper paddle wheel  25 , by which then an overlapping or imbricated output of the copies can be performed. In this folding mode, which necessitates the transport of the copies according to the conveying path  28 , the sensor pairs  3 ,  4 ,  6 ,  7 ,  8  and  9  are switched to detection mode, while the sensor pair  5  on the lower conveying path  23  has to be switched in such a way that this pair has to detect the absence of copies. Depending upon the selected output configuration for the copies in the double parallel folding mode, one of the paddle wheels  25  or  26  or both paddle wheels can perform the product output. In the event that copies are output via the upper paddle wheel  25 , the sensors  7  and  8  have to be switched to detection mode, after appropriate validation, while the sensor pairs  6  and  9  would have to be set to detect the absence of copies. 
     The sensors  7  and  8  in the paddle-wheel module of the folder  30  are validated in that they detect a copy very early, and output a valid signal when a number of copies corresponding to the distance from the cutting cylinder pair  2   b ,  17  to the respective sensor is located in the folder  30 . This applies in a similar way to the sensors  6  and  9 , if product output via the lower paddle wheel  25  is also provided. 
     The validation of the sensors  3 ,  4 ,  7  and  8  and, if necessary,  6  and  9  is performed based upon the progression of copies through the folder  30 , so that the signals from the sensors are viewed as valid only when the respective sensor can detect or not detect a copy very early, depending upon the folding mode. 
     FIG. 3 illustrates a copy conveying path corresponding to the second longitudinal folding mode, the copy stream dividing downline from the folding-jaw cylinders. 
     In this operating mode of the folder  30 , the copy conveying paths of which are identified by reference numeral  29 , the copies are crossfolded once downline of the folding-jaw cylinder  19 , picked off alternately by the cylinders  20  and  21  and pass via the upper and the lower conveying paths  22  and  23 , respectively, into the upper and the lower second longitudinal folding devices  10   b  and  10   a , respectively. Thereat, the crossfolded copies are provided with a second longitudinal fold and pass into an otherwise not specifically illustrated delivery in FIG.  3 . 
     In this operating mode of the folder  30 , the paddle-wheel module is inactive, and consequently the sensors provided thereat are inactive, i.e., switched to detect the absence of copies; on the other hand, the sensor pairs  3 ,  4  and  5  assigned to the conveying path  29  of the copies are switched to detect the presence of the copies, but under the condition that a validation of the copies detected by the sensor pairs  3 ,  4  and  5  can be performed only after the times at which the respective sensor pairs  1 ,  3 ,  4  and  5  can at the earliest detect a copy in accordance with the progression of copies through the folder. 
     In the configuration according to FIGS. 2 and 3, the number of copies that have entered the folder  30  can be determined via transmitters  2   a  and  14 , which are assigned to the cutting cylinder  2   b  or the drive  13  of the folder  30 , as already described above. 
     The functioning of the monitoring unit  12  integrated into the folder  30  and illustrated by FIGS. 1 to  3  may best be explained by using the flow chart according to FIG.  4 . 
     With the starting command  100 , initialization of the monitoring unit  12  is carried out, the latter first carrying out a self-test  101  and indicating its activation to the pressman by a visual or an acoustic device. In accordance with the predefined folder configuration, the set folding mode, for example double parallel fold  28  or second longitudinal folding mode  29 , is detected; this is carried out in step  102 ; depending upon the selected folding mode  28  or  29 , the sensor activation  103  activates the sensors  3 ,  4 ,  5 ,  6 ,  7 ,  8  or  9  which are located on the delivery path of the copies through the folder  30  corresponding to the selected folding mode  28  or  29 . These are stored in the memory  104 , with which a fault detection routine  104 . 1  is associated. 
     If the relevant sensors from the number of sensors  3 ,  4 ,  5 ,  6 ,  7 ,  8  or  9  have been activated and stored, the number of copies that have entered the folder  30  is determined in the counting stage  105 . 
     The following part of the diagram, between the counting stage  105  and the validation routine  106 , is carried out separately for each sensor  3 ,  4 ,  5 ,  6 ,  7 ,  8  or  9 , because each of these sensors has a different validation threshold by virtue of its different positions in the folder  30 . After the respective validation threshold has been exceeded, at the time from which the selected sensor can at the earliest detect a copy or can detect the lack of the copy, the corresponding sensor signal is for the first time recognized as a valid sensor signal; this is carried out by setting the sensors in  107 . 
     After that, depending upon the folding mode of selected sensors, a comparison operation  108  is carried out between the number of copies located in the folder  30  and the number of copies detected at the respective sensor. If the result is that there is no difference in the comparison operation  109 , which is carried out in real time, once again a branch is made to the signal validity query  106 , in order to check whether the validation threshold has actually been exceeded or not. 
     If the result of the comparison  109  is that more copies have been counted at the respective sensor than can have entered the folder, the folder  30  and/or the rotary printing machine are stopped by setting the switch-off signal  110 , because there could be a malfunction of the transmitters  2   a  and  14 . 
     If, on the other hand, the result of the comparison operation  109  is a lower number of copies detected by the sensors  3 ,  4 ,  5 ,  6 ,  7 ,  8  or  9  than have entered the folder  30 , it is first determined, via a sensor validity query  111 , whether this result was produced by a previously validated sensor. If a non-validated sensor is concerned, a branch back to the validation query  106  is made; if, on the other hand, the corresponding sensor had been correctly validated, it is determined that there was a paper jam  111 . 1 , which uses a switch-off command  112  to bring about the action of switching off the drive  13  of the folder  30  and/or of the rotary printing machine. When the command  113  is reached, the monitoring unit  112  has run through the program that controls the monitoring. 
     After the monitoring system has been initialized, it indicates to the pressman that it has been activated at creep speed or during the web threading phase. The system is capable of monitoring itself in such a way that, if at a sensor a number of copies is detected which is greater than the number of copies that has actually entered the folder  30 , the functional monitoring of the rotary encoder  2   a  or  14  is indicated. The monitoring system can be used in any folder and, in addition to detecting copy jam at creep speed or during web threading, it is also suitable and can be configured appropriately for normal operating speeds.