Abstract:
A method of operating a web printing press is provided. The method includes storing productivity data, press speeds and paper types of past print jobs run on the web printing press in a database; comparing a paper type of a new print job with the paper types of the past print jobs stored in the database to identify past print jobs with similar or the same paper type as the new print job; selecting a press speed for the new print job based on at least the productivity data of the past print jobs with similar or the same paper type as the new print job; and printing the new print job on the web printing press at the selected press speed.

Description:
The present invention relates generally to web printing presses and more specifically to a method and system for optimizing the speeds web printing presses. 
     BACKGROUND 
     Manual means and evaluation of gathered data have been applied to determine press run speeds and production optimization. 
     BRIEF SUMMARY OF THE INVENTION 
     A method of operating a web printing press is provided. The method includes storing productivity data, press speeds and paper types of past print jobs run on the web printing press in a database; comparing a paper type of a new print job with the paper types of the past print jobs stored in the database to identify past print jobs with similar or the same paper type as the new print job; selecting a press speed for the new print job based on at least the productivity data of the past print jobs with similar or the same paper type as the new print job; and printing the new print job on the web printing press at the selected press speed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described below by reference to the following drawing, in which: 
         FIG. 1  schematically shows a diagram of an offset newspaper web printing press according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically shows a diagram of an offset newspaper web printing press  10  according to an embodiment of the present invention. Web printing press  10  may have four printing units  12 ,  14 ,  16 ,  18 , which may be, offset lithographic web printing units printing on a web  20  in cyan, magenta, yellow and black, respectively. Each printing unit  12 ,  14 ,  16 ,  18  may include upper and lower plate cylinders  22 ,  24  equipped with corresponding printing plates and upper and lower blanket cylinders  26 ,  28  equipped with corresponding printed blankets. Each cylinder  22 ,  24 ,  26 ,  28  of printing units  12  may be driven by a respective individual motor  122 ,  124 ,  126 ,  128 . Cylinders  22 ,  24 ,  26 ,  28  of printing units  14 ,  16 ,  18  may be driven by motors  222 ,  322 ,  422 , respectively, or each cylinder  22 ,  24 ,  26 ,  28  of each printing unit  14 ,  16 ,  18  may be driven by an individual motor, as in printing unit  12 . Motors  122 ,  124 ,  126 ,  128  may be controlled by a controller  210 , which may also control motors  222 ,  322 ,  422  driving the cylinders  22 ,  24 ,  26 ,  28  of printing units  14 ,  16 ,  18 . 
     Web  20  may be slit by a slitter  30  into ribbons which are recombined at a roller  32 , which may be driven by a motor  132 . Slitter  30  may include a blade  29  and an anvil  31 , which may be driven by individual motors  129 ,  131 , which may be controlled by a controller  220 . Ribbons of web  20  then enter a folder  134  and are pulled over a former board  36  by draw rollers  38  to fold the ribbons longitudinally. At least one of draw rollers  38  may be driven by a motor  138 . Motors  132 ,  138  may be controlled by a controller  230 . A cross cutter  40  of folder  134  may then cut ribbons into signatures, i.e., newspaper pages  21 , which are gripped at a lead edge by a collect cylinder  42 . Collect cylinder  42  has pins that selectively articulate to release a page  21  for cross-folding, or retain a page to collect with other pages  21 . Pages  21  are then tucked and cross-folded into a folding cylinder, for example, jaw cylinder  44 . After folding, pages  21  may be released to, for example, a fan wheel. Cross cutter  40 , collect cylinder  42  and jaw cylinder  44  may be driven by respective motors  140 ,  142 ,  144 , which may be controlled by a controller  240 . Controller  240  may set the phasing between pins and tuckers of collect cylinder  42 , and control the phasing of jaws of jaw cylinder  44 , so that a cross-fold distance can be set. 
     A press control system  200  in wired or wireless communication with controllers  210 ,  220 ,  230 ,  240  may receive operational input data from controllers  210 ,  220 ,  230 ,  240  and may direct the speed at which web printing press  10  is operated by sending commands to controllers  210 ,  220 ,  230 ,  240 . Press system  200  controls the operation of components downstream of printing units  12 ,  14 ,  16 ,  18  based on the surface velocities of cylinders  22 ,  24 ,  26 ,  28  of printing units  12 ,  14 ,  16 ,  18 . Through communication with controllers  210 ,  220 ,  230 ,  240 , press control system  200  may collect running speed data for each component in printing press  10  and direct the speeds that motors  122 ,  124 ,  126 ,  128 ,  129 ,  131 ,  132 ,  138 ,  140 ,  142 ,  144  operate during each print job. Press control system  200  may be in wired or wireless communication with a human machine interface (HMI)  205 , which allows a user to view input data collected by press control system  200 . 
     Motors  122 ,  124 ,  126 ,  128 ,  129 ,  131 ,  132 ,  138 ,  140 ,  142 ,  144  may each include an internal or external speed sensor that sends measured values to the associated controller  210 ,  220 ,  230 ,  240 . In alternative embodiments, the use of controllers may range from each motor  122 ,  124 ,  126 ,  128 ,  129 ,  131 ,  132 ,  138 ,  140 ,  142 ,  144  being controlled by an individual controller or a single controller, such as for example press control system  200 , controlling all of motors  122 ,  124 ,  126 ,  128 ,  129 ,  131 ,  132 ,  138 ,  140 ,  142 ,  144 . The arrangement of controllers  210 ,  220 ,  230 ,  240  of  FIG. 1  is merely exemplary. 
     Press control system  200  works to optimize the printing of print jobs by printing press  10  by taking into account productivity data including a press productivity P prod , a press unproductivity P unprod  and a press productivity ratio P ratio  for printing press  10  for each individual print job. Press productivity P prod  for a print job as used herein is calculated by dividing a number of the signatures created that are acceptable for use in final printed products N good  (i.e., good count) by a run time T run  of the print job (P prod =N good /T run ). The run time T run  of the print job is equal to a total elapsed time of the print job T total  minus an amount of time printing press  10  had to be stopped (i.e., press is at zero speed) during the print job for job process corrections and adjustments T stop (T run =T total −T stop ). The total time T total  equals an end time of the print job T end  minus a start time of the print job T start (T run =T end −T start ). Press unproductivity P unprod  for a print job as used herein is calculated by dividing a number of the signatures that are unacceptable for use in final printed products N waste  (i.e., waste count) by the run time T run (P prod =N waste /T run ). Press productivity ratio P ratio  equals the press productivity P prod  divided by the press unproductivity P unprod (P ratio =P prod /P unprod ), i.e., good count N good  divided by waste count N waste (P ratio =N good /N waste ). 
     Before a new print job is run on printing press  10 , predetermined print job specifications for the new print job, including the paper type and Job ID for the new print job, may be provided to press control system  200 , for example by entering the predetermined job data through HMI  205  or providing the predetermined job data to press control system through a compute readable medium. Press control system  200  includes a data storage that includes measured job data for past print jobs run on printing press  10 . In particular, for past print jobs, the data storage includes the paper type, the press productivity P prod , the press productivity ratio P ratio , the run speed V run  and the make ready speed V ready . The run speed V run  is the speed of printing press  10  during production of printed products and the make ready speed V ready  is the speed of printing press  10  for job process corrections and adjustments. For the new print job to be run on printing press  10 , a speed optimization algorithm of press control system  200  searches the data storage for past print jobs of the same paper type. If previous jobs of the same paper type are found in the data storage, the speed optimization algorithm retrieves the press productivity P prod , the press productivity ratio P ratio , the run speed V run  and the make ready speed V ready  for the previous jobs of the same paper type and identifies the previously run print job for the same paper type that contains the maximum press productivity and the maximum press productivity ratio, i.e., the optimal previous print job. 
     The speed optimization algorithm of press control system  200  then sets the run speed and the make ready speed for printing press  10  for the new print job to correspond to that of the optimal previous print job. The run speed and the make ready speed for the new print job may not be exactly the same as the optimal previous print job, but may instead be based off of the run speed and the make ready speed of the optimal previous print job plus or minus one or more speed modifier constants. The speed modifier constants may be small incremental modifiers that are configurable to depend on the recent productivity of printing press  10  and the press productivity ratio trends of printing press  10 . For example, if print jobs with minimal waste have recently been run at higher speeds than at the time the optimal previous print job was run, then the run speed and make ready speed of the new job may be adjusted upwardly to account for this trend. Conversely, if the speed of printing press  10  has had to be reduced recently to minimize waste, then the run speed and make ready speed of the new job may be adjusted downwardly to account for this trend. 
     If previous jobs of the same paper type as the new print job are not found in the data storage, press control system  200  may set the run speed and make ready speed of printing press  10  based on default values. Alternatively, the run speed and make ready speed may be set by the operator via HMI  205 . 
     Press control system  200  may measure, for example with sensors at the end of printing press  10 , or be provided with data indicating a good count N good  for the new print job, a waste count N waste  for the new print job and a total number of signatures created by printing press  10  for the new print job N total  (i.e., total count) (N total =N good +N waste ). Additionally, press control system  200  may measure or be provided with a start time of the new print job T start , an end time of the new print job T end , an amount of time printing press  10  had to be stopped during the new print job for job process corrections and adjustments T stop , and an amount of make ready time that it took printing press  10  to restart after being stopped during the new print job T ready . This data, along with the run speed V run  and the make ready speed V ready  of printing press  10  for the new print job, may be used by press control system  200  to calculate the press productivity P prod , the press unproductivity P unprod , the press productivity ratio P ratio  and the job run time T run  of printing press  10  during the new print job. Then, the Job ID, the paper type, the press productivity P prod , the press unproductivity P unprod , the press productivity ratio P ratio , the job run time T run , the press run speed V run  and the make ready speed V ready  are stored in the data storage of press control system  200  for use in establishing optimum run conditions of future print jobs of the same paper type. 
     In a preferred embodiment, press control system  200  may control the operation of printing press  10  during an initial print job based on default parameters, which may be entered by the operator or in another conventional manner. During the initial print job, press control system  200  may monitor the operating parameters of components of printing press  10 , for example via communication with controllers  210 ,  220 ,  230 ,  240  and sensors  25 , and “learn” the total productivity P total  of printing press  10  for the initial print job. Press control system  200  may then store this information in an internal database. 
     As more print jobs are run on printing press  10 , more information is collected by press control system  200 . More information is then available to the speed optimization algorithm of press control system  200  to estimate the optimal run speed V run  and make ready speed V ready  of printing press  10  for a particular print job so press control system  200  direct the operation of motors  122 ,  124 ,  126 ,  128 ,  129 ,  131 ,  132 ,  138 ,  140 ,  142 ,  144  to achieve an optimum total productivity P total  for the particular print job. 
     In a preferred embodiment, operational risk factors may be introduced into the speed optimization algorithm to take some risk in increasing operating speeds beyond historical set points to probe performances versus risk and operate in ranges where a human operator may not have previously tested (although equipment operating ranges would be respected). 
     Furthermore the press control system  200  may display information through the HMI  205  to the operator of the printing press  10 . This information may be the highest productivity jobs and the associated data of those jobs, the Job ID for the particular print job, the run speeds of each motor  122 ,  124 ,  126 ,  128 ,  129 ,  131 ,  132 ,  138 ,  140 ,  142 ,  144 , the run speed V run  of printing press  10 , the make ready speed V ready  of printing press  10 , the total number of signatures N total  created for the print job, the number of signatures usable in final printed products N good , the number of signatures from the print job that are unusable and wasted N waste , the job start time T start , the job end time T end , the total job duration T total , paper type, the maximum speed during job V max , the amount of downtime during the print job T stop , the downtime reasons and the run duration T run . The operator may then use this information to alter the run speed V run  of printing press  10  for a print job. 
     In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.