EP0356705B1 - Data reading unit for an ink control devices - Google Patents

Abstract

For the simplification and less expensive manufacture of ink measuring apparatuses, a manual densitometer is connected to an ink control device. For simplifying operation, a user guide is provided by means of a display apparatus coupled to the densitometer. Using the manual densitometer, measurements can be taken on a printed sheet in freely selectable image zones. The image zones can be matched to the subject and the measuring points can be placed in the image region so that ink control strips are not required.

Description

The invention relates to a method and a device according to the preamble of claim 1 and a device for carrying out the method according to the preamble of claim 2.

It is common today to use control devices for ink supply on printing machines. Data about the condition of the printed image in each case must be recorded and compared with target data that were previously recorded. The device for carrying out these methods generally contain a densitometric measuring system, a computer system for recording and evaluating the data and color metering devices which are remotely adjustable. These systems are very complex since, for example, the densitometric measuring devices are built as automatic and motor-operated densitometers. In addition, a special print control bar must be provided on each print sheet, which contains measurement fields that the computer system needs for evaluating the print quality.

A color application control in a printing press by means of an automatically movable measuring head which scans a control strip which is also printed, and the acquisition of measurement data by means of a freely movable manual measuring head is known from EP 0 228 347 A1. EP 0 255 924 A2 also describes the possibility of obtaining measured values directly in the image, a hand-held measuring device (densitometer) being used. To avoid waste, the printing of an extra print control strip is avoided. EP 0 136 520 A3 describes a device for recording densitometric values from a pressure control strip using a manual densitometer. To the location of the Measured measuring fields are to be determined, in particular below the support table, absolute position sensors, the signals of which are evaluated in addition to the actual measuring signals of the densitometer.

The present invention is therefore based on the object of developing a method and a device according to the respective preamble of claims 1 and 2 in such a way that the quality of the color control remains the same, so that the mechanical outlay is considerably reduced and the installation of special pressure control officers can be dispensed with, but the data acquisition should still be able to be carried out safely.

This object is achieved procedurally by claim 1 and device-wise by claim 2.

The described method and the associated device have the advantage that complex measuring systems for data acquisition are no longer necessary. With the flexibly applicable hand-held densitometer or hand-held spectrophotometer, it is possible to take any data on a printed sheet. The display device working together with the densitometer or spectrophotometer ensures that the data is in the right place, also at the right time and also be recorded in a technically clean manner. This eliminates the need for special pressure control officers to control the ink supply. In addition, the densitometer or spectrophotometer used can also be used for special measurements in areas not used for color control.

The method and the device are described in more detail below with reference to figures.

Fig. 1

einen Druckbogen mit Bildzonen,

Fig. 2

das System zur Bildzonendefinition,

Fig. 3

das System zum Betrieb des Handdensitometers und

Fig. 4

einen Handdensitometer mit Anzeigeeinrichtung.

In detail show:

Fig. 1

a printed sheet with image zones,

Fig. 2

the image zone definition system,

Fig. 3

the system for operating the manual densitometer and

Fig. 4

a hand-held densitometer with display device.

In Fig. 1, the diagram of a printed sheet is shown as it can occur in reality. Different print patterns are arranged in different fields. E.g. part of the print area could be covered with text and another part with pictures. The structure of such a set is often arranged in columns. In an extreme case, a printed sheet is subdivided into, for example, 8 or 16 equally large fields and thus also into 4 or 8 equally wide columns. In the diagram shown, the columns that appear are labeled A, B and C. When dividing the ink in the inking unit of a printing press, this division can now be taken into account, so it has been proposed to divide the printing area into zones which are parallel to one another in the longitudinal direction of the sheet. Image zones A, B and C can be used for color control.

2 schematically shows the device with which the definition of the image zones can be carried out. A computer 1 is present therein, which handles data processing and organizational tasks takes over. An image zone memory 2 is connected to the computer 1. The image zone memory 2 is in turn connected to an input device 3. In the input device 3 it is possible to define at which positions of a printing sheet limits for image zones are to be set. This can be done, for example, using the keyboard on color control systems parallel to a printed sheet. However, it is also possible to use visual aids from a personal computer on whose screen markings adapted to the image zones are to be generated. For example, this is done by symbols for ink metering elements, according to the arrangement within the printing press. A data acquisition device 4, whose data are stored in an image data memory 5, is also connected to the computer 1. Finally, the computer is connected to a multiplicity of color metering units 7 via a data bus 6. The computer 1 accordingly establishes the connection on the one hand between the image zone memory and the color metering units and on the other hand also between the image data and the color metering units. This is done in such a way that when regulating a certain image zone, for example image zone B, the computer 1, because of its connection to the image zone memory 2, only controls the color metering units 7 which also belong to the image zone B. Furthermore, the image data obtained by the measurement with the data acquisition device 4 are covered in the image data memory 5 in relation to the respective image zone. The computer 1 is able to do this since it can always query the image zone assignment in the image zone memory.

The image data is acquired by an arrangement as shown in FIG. 3. For this purpose, the computer 1, as described, is connected to the image zone memory 2 and the image data memory 5. The data acquisition device 4 consists of a densitometer 8 and a display device 9, 10. An evaluation unit 11 is additionally provided within the computer 1. It is connected to the display device 10 and the densitometer 8.

The arrangement is carried out in the following manner for data acquisition or for the measurement of color density values: After the computer for measuring image data has been initialized, it releases the measurement on the display device 9. A readiness display can be generated with the help of LEDs. At the same time, the assignment to the respective image zone is shown in the display device 10 using the evaluation device 11. This can be a digital display. This enables the printer to immediately see whether the densitometer is ready and in which image zone it should measure. After the printer has measured, the data are transmitted to the evaluation device 11 and checked for plausibility and completeness. During the measurement, the display device 9 shows on one of its LEDs that the densitometer is now blocked for other work. When they have successfully passed the test, the data transferred to the evaluation device 11 are stored in the image data memory 5 in relation to the respective image zone. In addition, a release signal is again given to the display device 9, so that it can be seen that the densitometer is free again for other work. Finally, on the display device 10 in the digital display, the image zone is switched to the next image zone defined within a predetermined measuring cycle. This enables data acquisition for the next image zone.

Instead of a densitometer, a spectrophotometer can of course also be used for the data acquisition device. For this purpose, only the evaluation algorithms in computer 1 have to be designed differently.

4 shows a hand-held densitometer 12 suitable for data acquisition. It consists of a swiveling measuring head 13 and a foot with a direction finder 14. With the help of the direction finder 14, the densitometer can be placed freely at any position that is to be measured. The manual densitometer 12 is connected to the computer 1 via a data line 15. On the hand densitometer 12 or on the measuring head 13, an optical display 16 is attached. It can, for example, be attached to the measuring head with the aid of clips or held onto it with the aid of a rubber band. It can therefore be used on all possible types of densitometers. The optical display is also connected to the computer 1 via two lines 17. In the standby position, the measuring head 13 of the densitometer 12 is inclined upwards, as shown. The display devices 9, 10 are clearly visible on the optical display. The computer 1 controls the light-emitting diodes 9 or the digital display 10 in such a way that the operating personnel are informed directly about the operating actions to be carried out or possible. When the measuring head 13 is depressed, ie when a printed area is measured with regard to its color density values, the light-emitting diodes 9 are switched in such a way that, on the one hand, a light-emitting diode lights up in red to indicate that the densitometer is currently busy with a measurement. Meanwhile, a second light emitting diode is not illuminated. When the data has been transferred to the computer 1 and checked there, the second LED either lights up with a red flashing light or in green. Flashing red light means incorrect measurement or incomplete data transmission and green light means the measurement was OK and the measuring process can continue. Then the first LED is switched to green again. At the same time, as already described, a digital display shows the next image zone determined in the previously determined measurement sequence, with its letter or its numerical order. The operating display on the densitometer is therefore independent of the densitometer in terms of its connection and is only used for the precise and precise information of the operating personnel at the measuring location.

The processes described are intended for the rationalization and simplification of color control systems. In particular, complex automatic color measuring devices are eliminated. In addition, the freely positionable hand densitometer 12 can be used to measure anywhere in the printed sheet X. Of course must the color control strip can not be omitted, but measurements can of course also be carried out on selected color measuring fields within the color control strip using the hand densitometer. However, it is also possible to use the densitometer to measure certain points that the printer knows from his experience as critical. The type of display is not limited to the optical display 16 described with light-emitting diodes 9 and digital display 10. Here, for example, acoustic display devices are also conceivable.

Reference symbol list

1

computer

2nd

Image zone memory

3rd

Input device

4th

Data acquisition device

5

Image data storage

6

Data bus

7

Color dosing units

8th

Densitometer

9

Display device (light emitting diode)

10th

Display device (digital display)

11

Evaluation unit

12

Handheld densitometer

13

Measuring head

14

DF device

15

Data line

16

Optical display

17th

management

X

Printed sheet

A

Image zone

B

Image zone

C.

Image zone

Claims (6)

1. Process for capturing data of a printed image for the control of ink feed in printing presses in which, by means of a photoelectric measuring device, data are generated, stored in a store and evaluated in a calculator for control of a zonally divided ink metering unit, characterised in that the printed image is divided corresponding to its make-up into image zones and this division is stored, wherein each image zone can extend over a differing number of zones of the ink metering device then in the image region of each image zone, data are captured by means of a photoelectric hand measuring device that these data are checked in a calculator for completeness and correctness and on successful examination are stored and the measuring device thereafter freed for a next measurement and on non-successful examination the repeat of a measurement is permitted, and that the control in the zones for each image zone takes place correspondingly to the measured value captured in the image zones.
2. Apparatus for carrying out the process according to Claim 1 with an electrical measuring device for generating data, a store for storing these data as well as a calculator, by which the evaluation of the data for control of a zonally divided ink metering device takes place, characterised in that an input device (3) for the definition of freely choosable image zones is provided, which is connected with an image zone store (2) connected to the calculator (1), that via the calculator (1) as well as a data bus (6) a plurality of the zone or ink metering unit is controllable taking into account the data deposited in the image data store (5) and in the image zone store (2), and that an indicator device (9, 10) is connected with the calculator by means of which the operational condition of a photoelectric hand measuring device can be indicated.
3. Apparatus according to Claim 2, characterised in that the photoelectric hand measuring device is constructed as a hand densitometer or hand spectrophotometer which is connected via a data lead (15) with the calculator (1).
4. Apparatus according to Claim 2, characterised in that the checking table with the operational elements of the control device for the zonally divided ink metering unit is constructed as an input device (3) for the definition of the image zones.
5. Apparatus according to Claim 2 and 3, characterised in that the indicator device (9, 10) for the operational condition of the photoelectric hand measuring device (4) has an optical indicator of light emitting diodes (9) to indicate the data capture and transfer of respective signals and a digital indicator (10) to give a characterisation of the image zone to be measured.
6. Apparatus according to Claim 5, characterised in that the indicator unit (9, 10) is connected as a slave unit connected independently with the calculator (1) and which can be applied releasably to a commercially customary photoelectric hand measuring device.

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