DE102007021039A1 - Method for operating a printing machine - Google Patents

Abstract

The invention relates to a method for operating a printing machine, in particular an offset printing machine, wherein in printing units of the printing machine, a sheet-shaped or web-shaped printing material with the help of printing plates, which are made taking into account prepressure-based image data and substrate data is printed. According to the invention, at least one unprinted and / or at least one printed section of the printing material is measured, in which at least one determined actual value is compared with at least one printing material-dependent setpoint value to determine on the basis of the comparison whether the substrate actually used corresponds to the printing material in terms of its properties or printing material data on the basis of which the printing plates used for printing are made.

Description

The Invention relates to a method for operating a printing press, in particular an offset printing machine, according to the preamble of the claim 1.

In Sheet-fed presses become a sheet-shaped substrate, in shape so-called printing sheet, moved by several printing units to on the arcuate Substrate to apply a printed image. For printing see the Printing units Printing forms, typically printing plates, using, the considering from prepress-based image data and considering be prepared from substrate data. So has the used substrate will affect the print produced Print image, which is why data about the substrate already in the printing forme production or in the Prepress taken into account become. In offset printing, the division of the types of substrates takes place according to certain characteristics, namely after the color of unprinted sections of the substrate, after the gloss of unprinted sections of the substrate, after dot gain or the printing characteristics of the printing inks when printing, after in print reproducible color range, as well as after show through a print image applied to the substrate during printing. The color gamut that can be reproduced in print is also Gamut and show through is also called opacity.

Becomes at the actual Printing on the substrate used in the press a substrate, that of the substrate, based on its properties or Data that the printing forms are made deviates, so may the Coloring in Move print to the point where waste is printed. It may be the complete print run is unusable and must be destroyed. This causes high costs. So far, there are no procedures for operation a printing press known to address this problem.

Of these, The present invention is based on the object, a novel method of operating a printing press, in particular an offset printing machine to create.

These The object is achieved by a method according to claim 1.

According to the invention, at least a blank and / or at least one printed section of the Measure substrate, in which case at least one determined Actual value is compared with at least one printing material dependent setpoint, to determine, based on the comparison, whether the one actually used Printing material in terms of its properties or substrate data that Substrate based on which they were used for printing Printing forms are made.

With the method according to the invention is proposed for the first time, at least one unprinted and / or to measure at least one printed section of a substrate, and to determine actual values, which are dependent on printing material-dependent setpoints be compared. Based on the comparison, it can be stated whether the actual the substrate used for printing corresponds to the substrate, Based on its properties in prepress printing forms have been produced. Optionally, based on this comparison A printing process will be aborted to prevent the printing of waste to avoid.

preferred Further developments of the invention will become apparent from the dependent claims and the following description.

embodiments The invention will be described, but not limited to, with reference to the drawing explained in more detail. there shows:

1 : A schematic representation of a trained as a sheet-fed press printing machine to illustrate the inventive method for operating a printing press.

1 shows a highly schematic representation of a sheet-fed press 10 , the sheet-fed press 10 an investor 11 , a boom 12 and several between the investor 11 and the boom 12 positioned printing units 13 having. The printing works 13 are preferably designed as offset printing units and are used to apply partial printing images on the substrate to be printed.

From the printing works 13 are each a form cylinder 14 , a transfer cylinder 15 as well as an impression cylinder 16 shown, wherein on the forme cylinders 14 Printing forms and on the transfer cylinders 15 Transmission forms are positioned. The printing plates are usually printing plates and in the transfer forms to blankets, which is why the forme cylinder 14 also as a plate cylinder and the transfer cylinder 15 Also referred to as rubber cylinder.

• – die Farbe von unbedruckten Abschnitten des Bedruckstoffs,
• – den Glanz von unbedruckten Abschnitten des Bedruckstoffs,
• – die Tonwertzunahmen bzw. die Druckkennlinien der Druckfarben beim Drucken,
• – den wiedergebbaren Farbumfang beim Drucken, den so genannten Gamut, und
• – das Durchscheinen eines Druckbilds durch den Bedruckstoff, die so genannte Opazität.

The on the form cylinders 14 Positioned printing forms, which are used for printing, are produced in a so-called prepress on the basis of print image data and on the basis of data or properties of the substrate to be printed. In the data or properties of the printing substrate, which are to be considered in the printing forme, is in particular to

• - the color of unprinted sections of the substrate,
• The gloss of unprinted sections of the printing substrate,
• The tonal value increases or the printing characteristics of the printing inks during printing,
• - the reproducible color gamut when printing, the so-called gamut, and
• - the transparency of a printed image through the substrate, the so-called opacity.

in the For the purposes of the present invention, at least one unprinted Section and / or at least one printed section of the substrate measured, in which case at least one determined actual value with at least one printing material dependent Setpoint is compared. Based on the comparison, it is determined whether the actual to Printing used in terms of its properties or substrate data corresponds to that substrate, based on in the prepress, the printing forms used for printing have been produced.

In the case, that is determined that the substrate actually used from that substrate on the basis of which to print printing forms used have been produced, deviates Automatically generates and signals an error message or warning message. For big ones Deviations in the characteristic between the actually used Substrate and the presupposed in the prepress printing material is if necessary, the printing machine stopped or the printing of Edition interrupted. For relatively small deviations, however can be controlled by influencing pressure parameters, to minimize the color deviations so caused.

Then, when at least one unprinted portion of the printing material is measured, the measurement of the or each unprinted portion is carried out by means of a color measuring device and / or by means of a gloss meter and / or with the aid of an opacity meter. 1 shows an example of a color measuring device 17 for unprinted sections of the substrate upstream of the printing units 13 is positioned and therefore detects the substrate before printing the same metrologically. The measuring device 17 to measure the or each unprinted portion of the substrate misses the same inline or online within the printing machine during the printing process or during the print production.

Further shows 1 a measuring device 18 , which is used to measure at least one printed portion of the printing substrate, wherein the or each printed portion is measured by means of a color measuring device.

According to 1 is the measuring device 18 downstream of the printing units 13 integrated into the sheet-fed press, so that the measurement of the or each printed portion after printing of the substrate takes place, again inline or online during the print production.

By means of or each measuring device 17 . 18 determined actual values are sent to a control device 19 in which the determined actual values are compared with printing material-dependent setpoints. Each determined actual value is in the control device 19 is compared with a plurality of target values stored for different types of substrates having different properties or substrate data in order to determine on the basis of the comparison whether the substrate actually used corresponds in terms of its properties or printing data data to the substrate on the basis of which the printing plates used for printing were produced.

This comparison can be made with the aid of in the control device 19 integrated software. Alternatively, this comparison software can also directly into the or each measuring device 17 . 18 be integrated.

Preferably the measurement of the or each unprinted section takes place as well measuring the or each printed section using a Color measuring device, namely a spectral color measuring device, the actual values in the so-called L * a * b * color space determined. These actual values in the L · a · b color space are used with setpoints in the L · a · b color space compared, namely such that each actual value with several stored for different types of substrates Setpoints is compared. Based on this comparison then becomes Determined if the actual used substrate with regard to its properties or substrate data corresponding to the substrate on the basis of which in the prepress Printing plates have been exposed.

The Measuring the or each unprinted section and measuring the or each printed section using the color measuring device, namely the spectral color measuring device, preferably according to standards. This is opposite to the color measuring device on the other side of the substrate and thus along the transport path of the printing material through the Pressing machine positioned a black measuring pad.

With Help of the method according to the invention can be checked inline or online for print production, whether to print one indeed used printing material in terms of its properties or substrate data on the basis of which in the Prepress printing plates have been produced.

Become only relatively small deviations of the type of printing material are detected Thus, by regulating process parameters, the resulting Color deviation can be compensated. For relatively large deviations Preferably, the printing process is aborted to prevent the printing of To avoid waste.

The Invention is in sheet-fed presses and web-fed presses used. The invention can be the one-sided and two-sided Printing on substrates are used, with the two-sided Printing in sheet-fed printing machines referred to as perfecting is, even if the substrate on both sides has different properties. Then for the two Pages according to different setpoints deposited.

10

Sheetfed

11

investor

12

boom

13

printing unit

14

form cylinder

15

transfer cylinder

16

pressure cylinder

17

measuring device

18

measuring device

19

control device

Claims (12)

Method for operating a printing machine, in particular an offset printing machine, wherein in printing units of the printing press an arcuate or web-shaped printing material is produced with the aid of printing plates which are produced with consideration of pre-press-based image data and printing material data, characterized in that at least one unprinted and / or or at least one printed section of the printing material is measured, wherein in this case at least one determined actual value is compared with at least one printing material-dependent setpoint to determine based on the comparison, whether the actual substrate used in terms of its properties or substrate data corresponds to that substrate on the basis of which are made for printing used printing plates. Method according to claim 1, characterized in that that the or each unprinted section using a color measuring device is measured. Method according to claim 1, characterized in that that the or each unprinted section using a gloss meter is measured. Method according to claim 1, characterized in that that the or each unprinted section using an opacity meter is measured. Method according to one of claims 1 to 4, characterized that the or each printed section using a color measuring device is measured. Method according to one of claims 1 to 5, characterized that each determined actual value with several, for different types of substrates stored with different properties or substrate data Setpoints to determine, based on the comparison, whether the actual used printing material in terms of its properties or substrate data that Substrate based on which they were used for printing Printing forms are made. Method according to one of claims 1 to 6, characterized that the or each unprinted section before printing the Print substrate and / or measured after printing on the substrate becomes. Method according to one of claims 1 to 7, characterized that the or each printed section after printing on the substrate is measured. Method according to one of claims 1 to 8, characterized in that the color measuring device is a spectral color measuring device is used, the actual values in the L * a · b color space determined, this Actual values in the L · a · b color space with nominal values in the L · a · b color space be compared. Method according to one of claims 1 to 9, characterized that if it is determined that the actual substrate used from that substrate on the basis of which to print used printing forms deviates, automatically an error message is generated and displayed. Method according to one of claims 1 to 10, characterized in that, when it is determined that the actually used Be If the printing material used is different from the printing material on the basis of which the printing plates used for printing deviate, parameters of the printing process are automatically adapted. Method according to one of claims 1 to 11, characterized that measuring the or each unprinted portion of the substrate and / or the or each printed portion of the substrate inline or online for printing.