CN115016745A

CN115016745A - Optimized machine speed

Info

Publication number: CN115016745A
Application number: CN202210207513.4A
Authority: CN
Inventors: I·席尔茨
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 2021-03-05
Filing date: 2022-03-04
Publication date: 2022-09-06
Also published as: DE102022102985A1

Abstract

A method for optimizing the production speed of a printing press having a computer. The invention is characterized in that the production speed of the printing press is optimized by a computer such that the criteria input by the operator into the computer of the printing press are met as well as possible.

Description

Optimized machine speed

Technical Field

The invention relates to a method for optimizing the production speed of a printing press having a computer.

Background

In particular in offset sheet printing presses with very small print counts of less than 300 sheets, target conflicts often occur between production speed, production time and waste sheets. In the case of a print count of only a few sheets, the proportion of waste sheets is disproportionately high, since the start-up of the printing press requires a lot of time. In offset printing presses, it is desirable to achieve a reliable production process with acceptable print quality that remains unchanged at a constant machine speed. In this connection, it is expedient in the case of small print counts to reduce the production speed in order to produce fewer waste sheets, as a result of which the production process can be shortened at the same time, since the substrate to be removed must be smaller than the waste sheets and the production process as a whole is thus shorter, despite the printing press having a lower production speed, since the start-up process can be shortened. Heretofore, the reduction of startup waste and startup time has not been considered significant in relation to the total production cost and total production time.

Disclosure of Invention

The object of the present invention is therefore to provide a method for optimizing the production speed, in particular in offset sheet-fed printing presses with computers, which optimizes the overall production duration and the production outlay with a low number of prints on a small number of sheets.

According to the invention, this object is achieved by the solution of the preferred embodiment of the invention, and the advantageous configuration of the invention results from the alternatives, the description and the examples. According to the invention, the production speed of the printing press is optimized by the computer such that the criteria or criteria input by the operator into the computer of the printing press are met or met as well as possible. It is thus possible for the operator, in particular for small print counts, to control the optimization process in such a way that, for example, as few waste sheets as possible, as short a production time as possible or as little production effort as possible are specified as criteria. The operator has the possibility of selecting and inputting the criteria themselves into the computer, which is not linked to the criteria programmed in the computer. In contrast to the prior art, the option of being freely selected by the operator or the print shop customer is novel, since only the optimizations specified in the machine can be implemented there. Based on the criteria selected by the operator, the computer of the printing press calculates an optimum production speed which can well be below the maximum production speed of the printing press, since not only waste sheets but also the start-up procedure of the printing press to the printing speed are to be taken into account in conjunction. The computer of the printing press takes into account, in particular, the acceleration behavior of the printing press, so that the production speed can be adapted to the respective acceleration capability of the printing press. Here, the computer need not be present in the printer itself, but it may also be an external computer, in particular a cloud solution communicating with the printer. It is not important to the present invention where the calculation of the optimization is performed.

In the first configuration of the invention, the minimization of the production time is input by the operator as a criterion. In this setting, the production speed is optimized in such a way that it is optimized during the production process taking into account the start-up process and the waste sheets and the clear print substrate occurring there, so that overall a minimum of time is required for crossing the production process and the start-up process.

In a further embodiment of the invention, it is provided that the criteria input by the operator include a minimization of waste sheets in the produced printing material. In this case, the production speed of the printing press is optimized such that as few waste sheets as possible occur during the start-up and production process and thus, in particular, in the case of very small print counts of only 300 or less printing material. This makes it possible to remove only a small amount of the substrate as waste. Furthermore, it is advantageously provided that the computer of the printing press recalculates the optimized production speed during operation of the printing press after each stoppage or each printing interruption, depending on the machine state and the printing task being produced. Machine state is also understood to mean transactions such as remaining print counts, remaining stacks, etc. Depending on the total number of impressions for the print job and the time of the machine stoppage or interruption, the computer, using the data of the print job and the amount of printing material already produced, determines the corresponding remaining number of impressions that are still to be produced after the stoppage or interruption. This makes it possible, in particular in the case of small residual print counts, to reduce the production speed compared to the production speed before a stoppage or interruption of printing, in order to effectively minimize the printing material still remaining in terms of production costs or waste by minimizing waste sheets. Thereby it is ensured that: depending on the time of the machine stoppage or the occurrence of the printing interruption, the printing material still to be produced after the production is produced at the optimum production speed and the production speed before the stoppage or the printing interruption is not simply accepted or adopted.

In a further embodiment of the invention, the computer is provided with data relating to the printing material costs and the production costs as optimization criteria and calculates therefrom an optimized production speed which results in the lowest overall costs. In this embodiment of the invention, the computer calls up the printing material costs and the production costs, which are stored in a database of the computer or in another computer accessible via an internet connection. In addition, the printing material costs for the print job to be completed are known to the computer of the printing press from the print job data of the print job to be completed. The matching substrate costs are also known to the computer by comparison with a database, and the computer uses the production costs saved for the respective printing press to calculate an optimum production speed for the number of prints of the print job to be completed, so that the overall costs for completing the print job are minimized.

It is furthermore advantageously provided that, when a print job in the print waiting queue or the printing press waiting queue is released, the computer advises the operator of the optimized production speed of the printing press on the display device and, if the operator is responding, takes over the optimized production speed into the control of the printing press to process the print job. The user of the printing press therefore does not have to be concerned with or take into account the optimized production speed of the printing press, but rather the computer itself automatically determines the optimized production speed on the basis of the data of the printing job and from the data of the database of the printing material costs or production costs that can be accessed by the computer and then displays the production speed on a display device, for example a screen, to the operator. The operator then merely has to answer or sign in the production speed, which is then automatically transferred to the control of the printing press and used to process the print job by the printing press. At the same time, however, the operator of the printing press has the possibility of manually changing the production speed suggested by the printing press and then operating the machine faster or slower. The method according to the invention is therefore used in particular to support inexperienced operators of a printing press so that they obtain an auxiliary function for selecting an optimum production speed of the printing press.

A further embodiment of the invention is characterized in that machine states of the printing press which impair the printing quality are recorded and stored in the computer and the production speed is optimized by the computer on the basis of the stored machine states. In this way, an optimized production speed can be calculated on the basis of the already completed print jobs and the machine states occurring during production and stored in the computer of the printing press for future print jobs. This has the advantage that the computer of the printing press learns how the determined machine state influences the print quality during production as the number of print jobs increases and which adaptations of the previous production speed can minimize the negative impact on the print quality. Thereby, an optimization of the production speed of a future print job may benefit from an optimization of the production speed of a previous print job. An exemplary event of the machine state is a sheet stop (bogestopper), which occurs again and again in a sheet offset printing press. The sheet stoppage results in the production process having to be interrupted and in particular a plurality of printing materials damaged, which must be removed from the printing press before the production process can be continued again. By recording the past sheet stop and the production speed used here, the production speed can be optimized without sheet stop by comparison with the past production speed. In this way, production speeds which often lead to sheet stoppages can be consistently avoided in future printing jobs. In addition to the sheet stopping and production speed, the computer stores the used printing material, so that for future printing speeds as well as sheet stopping and learning functions of the used printing material are evaluated with regard to the weakness or sensitivity of the sheet stopping and the production speed is optimized.

In a further embodiment of the invention, the machine states are stored in a database and transmitted to a plurality of printing presses having control computers via an internet connection. By the printing press being networked to one another via the internet, the plurality of machines can call up the database and thus learn from one another the machine speeds from the past and the associated production speeds. Since not every machine already completes every printing job at every production speed and usually also uses different printing materials, a plurality of printing presses can learn from one another in such a way that they can also benefit from the events and machine states of the printing materials and production speeds of other printing presses, which they themselves have not used in the past. This enables optimization of production speed across empirical values for multiple presses.

Furthermore, it is advantageously provided that the computer of the printing press stores, for each print job, the print substrate used in processing the print job and the production speed used there and uses this to calculate an optimized production speed when processing future print jobs having the same or similar print substrates. The aforementioned optimization can be used in future print jobs, in particular similar print jobs, similar to the machine state that occurs, in order to optimize the production speed, based on the printing material used at each print job and the production speed. This also improves the learning function of the printer control apparatus equipped with the method of the present invention.

Detailed Description

The invention is explained and illustrated in more detail below with the aid of examples.

The computer of the printing press is equipped with software which calculates the optimum production speed from the machine data, such as the acceleration performance of the printing press (which is stored in the software) and the number of prints of the print job, and advises the operator of the optimum production speed on the screen of the printing press and/or automatically takes over the control of the queue. The production speed is recalculated and adapted each time after the machine has been stopped, so that a minimization of the remaining production time is achieved even with small remaining print counts (in particular < 300 sheets).

In principle, the operator of the printing press can select between a plurality of optimization options on the screen. One option is the calculation of economically optimal production speeds when there are machine and personnel costs including paper and production costs. In the case of expensive paper and small print count, avoidance of waste sheets can be more important than reduction of production time. The production time is calculated from the acceleration time 2+ (number of impressions/production speed). This makes it possible to reduce the production time while taking acceleration and the number of prints into consideration.

For example, a sheet offset printing press typically requires about 15 seconds for a production speed of from 3000 sheets/hour (Bogen/h) up to 18000 sheets/hour. This time also occurs during braking. The printed sheets are considered waste sheets and may not be sold because of insufficient printing quality. Production times in a printing run can be minimized by a lower production speed at print counts of less than 300 sheets, examples of which are shown below:

in the case of a print count of 100 sheets and a production speed of 13000 sheets/hour instead of 18000 sheets/hour, the total production time is reduced from 50 seconds (50s) to 47.7 seconds (47.7 s). This results in a time saving of 4.6% in terms of production time, although the production speed becomes slow. In the case of a print count of 50 sheets and a production speed of 9000 sheets/hour instead of 18000 sheets/hour, the total production time is reduced from 40 seconds to 32 seconds. This corresponds to a time saving of 20%.

The reduction of the acceleration time additionally saves the starting of waste sheets, which is significant in the case of small print counts or is decisive even for calculating the production speed in the case of expensive paper, examples of which are shown below:

in the case of a 100-sheet print count and a production speed of 13000 sheets/hour instead of 18000 sheets/hour, the acceleration time is reduced from 15 seconds to 5 seconds to 10 seconds. The number of waste pages that do not occur here is reduced from 32 by 18 to 14. This means 56% less waste pages. In the case of a print count of 100 sheets and a production speed of 10000 sheets/hour instead of 18000 sheets/hour, the total production time remains the same, but the acceleration time is reduced by 8 seconds and the waste pages are reduced by 25 sheets, which means that 78% less starting waste pages. In the case of a print count of 50 sheets and a production speed of 9000 sheets/hour instead of 18000 sheets/hour, the deceleration time is reduced by 9 seconds. The number of waste pages that do not occur is reduced by 27 pages. As a result, 84% less waste sheets are produced, which results in a significantly more advantageous production outlay. In this case, the deceleration time during the braking of the machine is irrelevant when calculating the waste pages.

A further optimization proposal takes into account the last speed used in the case of a specific sheet on the printing press for a comparable number of prints. If the printing material is not printed at the maximum speed in its final use on this or a similar machine, the computer also does not recommend this maximum speed as the production speed, since a high probability of considering the printing material as being at the maximum speed is problematic.

It is also proposed that empirical values be taken into account, which the printing press or similar printing press has obtained in the past with this or a similar substrate. For example, the sheet stop can be stored in the machine mode or centrally, for example in a sheet-fed database, for the printing material used, with the corresponding production speed, at the production speed up to now, and then, depending on this information, a suggestion can be displayed on a screen by a computer, which can be accepted by the operator of the printing press. If, in addition, a maximum speed is suggested due to a large margin, this maximum speed can be reduced due to empirical values such as a manual determination of a sheet stop or a lower speed.

Claims

1. A method for optimizing the production speed of a printing press having a computer, characterized in that the production speed of the printing press is optimized by the computer such that the criteria input into the computer of the printing press by an operator are met as good as possible.

2. The method of claim 1, wherein the criteria input by the operator includes minimization of production time.

3. A method according to claim 1 or 2, wherein the criteria input by the operator include minimization of waste in the produced substrate.

4. Method according to any one of the preceding claims, characterized in that the computer of the printing press recalculates the optimized production speed after each stoppage or each printing interruption in the operation of the printing press, depending on the machine state and the printing task being produced.

5. Method according to one of the preceding claims, characterized in that data on the substrate costs and the production costs are provided to the computer as optimization criteria and the computer calculates therefrom an optimized production speed which contributes to the lowest overall costs.

6. Method according to any one of the preceding claims, characterized in that, when releasing a print job in the print waiting queue, the computer advises the operator on a display device of the optimized production speed of the printing press and, in the event of positive operator response, takes over the optimized production speed into the control of the printing press for processing the print job.

7. Method according to any of the preceding claims, characterized in that the machine state of the printing press that impairs the printing quality is recorded and stored in a computer; and optimizing the production speed by the computer based on the stored machine state.

8. The method of claim 7, wherein the machine state comprises an event such as a sheet stop with production speed used in the past.

9. Method according to any of the preceding claims 7 or 8, characterized in that the machine state is stored in a database and transmitted to a plurality of printing presses with control computers via an internet connection.

10. The method according to any of the preceding claims,

the computer of the printing press stores in each print job the print substrate used in processing the print job and the production speed used in this process and uses this production speed in the processing of future print jobs having the same or similar print substrates to calculate an optimized production speed.