DE3338883A1 - METHOD AND DEVICE FOR DETERMINING THE PRINTING AREA - Google Patents

Description

Method and device for determining the printing area portion

The invention relates to a method and a device for Determination of the printing area portion of an original outside or inside a printing machine by means of incident light or Transmitted light method

Is known from DE-OS 30 29 273 a device for Measuring the printed image area of an offset printing plate in which a photoelectric detector device is in the form a straight line for optically scanning and determining the printing area and non-printing area of a printing plate with calibration mark is used. A conveyor is used to transport the printing plate or the detector device used so that the detector device scans the printing plate. The evaluation and determination of the Print image area is carried out by a processor unit, wherein a calibration is carried out and the print image area of the print area corresponding to the type of printing plate is detected.

The disadvantage here is that the measurement of the printed image area is necessary an elaborate photoelectric detector device becomes necessary and by using two in parallel

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linear light sources arranged in relation to one another reduce the measurement error due to thermal deformation, but not is eliminated.

It is the aim of the invention to provide a method and a device for determining the printing area portion create, for which a less complex photoelectric detector device is required and with which a higher one Measurement accuracy is achieved.

The technical object of the invention is to create a method and a device with which less photoelectrics Basic elements for the detector device are required and the thermal deformations to be measured Templates are eliminated during the measuring process.

The object is achieved in that the template by means of a mechanical pulling force on a curved or flat surface is tensioned and all sensor fields arranged on a mounting rail before being transported to the print image area of the template by means of calibration rods located transversely to the conveying direction be calibrated at the same time, and that the template, which is divided into columns, begins with a small area in all columns is scanned and the measured values are stored in a computer and integrated for the purpose of forming the amount.

The scanning of the original is advantageously carried out in such a way that the small area beginning in all columns at the same time Scanning within the columns takes place in a meandering manner.

For scanning over a particularly small area, it is advantageous to scan within partial columns along the widths of the color zones Make columns of the template.

The design of the template's stretching becomes effective in that the template receives the original position by being clamped onto the printing cylinder. When designing the «· direction for performing the method, it is advantageous if in the detector device on a fastening device equally spaced sensor elements are arranged and the fastening device with a for generating a Transverse and longitudinal movement serving conveyor is connected.

In the following, the invention will be based on an exemplary embodiment are explained in more detail. In the drawing, the figure shows the schematic arrangement of the device during a meandering scan of the original ·. With this scanning process, the scanning process begins in all color zone widths Columns 1.1. until 1.5. the original on the same side. The measured values are from the sensor fields 2.1. until 2.5. removed and saved. Before the actual measuring process begins, the sensor fields are 2 * 1. to 2 · 5 · during the Transports calibrated via the calibration standards 3, 4. The transport is carried out by the Bewegungsvlnfeichtung 5 so that the mounting rail 8 the sensor fields 2.1. until 2.5. after the first measuring process of the remitted or transmitted light in the lifting direction 7 to the second Sensor field-sized areas of the ink zone-wide columns. This movement is carried out at a high speed, for example by an impulse-controlled Pull magnets, a stepper motor or the like.

The width of the sensor fields 2.1. until 2.5. corresponds to the half the width of the color zone-wide column of the original. is this Äeßvorgang ended, then the movement of the mounting rail takes place 8 in the main scanning direction 6 to the next line of the original · The distance covered is as great as the length of the individual sensor fields 2.1. until 2.5. Are the Once measured values have been taken and saved, the sensor fields 2.1 are positioned again. up to 2.5 · to the second aensor field size Area of the line in the color zone-wide columns of the original, etc. This results in a meander-shaped scanning path 9. By using this method, fewer sensor elements are required for scanning the original. Of the This reduces costs in terms of costs compared to using a complete line of sensors. The Template z. B. falsify thermal deformations caused by a printing plate and the associated unevenness the measured values of the intensity renovations of the tranaaited resp. remitted lights «, the consequence is a deviation of the original This means that an exact determination of the amount of color required is not possible possible.

Uta these deformations to ineffective during the measuring process make, the template is tensioned at the edges by means of a mechanical tensile force, which can consist, for example, of a fastening rail and a spring system. In contrast to the known arrangement with two light sources arranged parallel to the printing plate, which are at a certain distance must be arranged to the printing plate, the method according to the invention does not result in an optimal measured value, but the causes of the misleading falsifications are eliminated.

The following arrangement is used as the device for carrying out the described method.

The sensor fields designed as flat diodes 2.1. until 2.5. are each connected upstream of an amplifier, dle;: m ± t their outputs are switched on to an LTuI tipi exhaust. Ground the analog values at the output of the multiplex module « by a subsequent analog / digital converter into digital Signals converted. These digital signals are sent to a microcomputer, which saves and integrates the values. After each switchover of the movement device 5, the interrogation of the measured values is repeated by the !.! ultlplex module made

1.1. Template gap 1.2. Original gap β 1.3. Template column 1.4. Original gap β 1.5. Template gap 2.1. Sensor field 2.2. Sensor field 2.3. Sensor field 2.4. Sensor field 2.5. Sensor field 3. Eichnonaale 4th Calibration standards 5 Movement device 6th Main scanning direction 7th Subdivision 8th Mounting rail 9 Scanning path

Claims (5)

Claim Method for determining the printing area portion of an original by optical scanning and determining the Print area and the print-free area by the original or the photoelectric detector device by means of a Conveyor are positioned and the fotoelectri-3eheη Basic element · are calibrated by means of calibration standards, characterized in that a) the original by means of a mechanical tensile force a curved or flat surface is clamped, b) all arranged on a mounting rail (8) Sensor fields before the transport to the print image area of the original through transverse to the conveying direction Calibration standards (3, 4) are calibrated at the same time, c) the original, which is subdivided into columns, is scanned over a small area starting simultaneously in all columns and d) the measured values are stored in a computer and integrated for the purpose of forming the amount. 2. A method for determining the printing area proportion according to claim 1, characterized in that the in all Columns simultaneously beginning small-area scanning within the column takes place in a meandering manner. 3. Procedure for determining the printing area share according to claim 1, characterized in that the scanning is carried out within partial columns along the widths of the color zones Columns of the template is made 4. Procedure for determining the printing area share according to ünojiruch 1, characterized in that the template the original position by clamping on the printing cylinder receives. 5. Device for performing the method according to claim 1, with a photoelectric detector device and a for transporting the feed device or the detector device serving conveyor device, characterized in that that equally spaced sensor elements are arranged in the detector device on a fastening device and the fastening device with a conveyor device serving to generate a transverse and longitudinal movement connected is. Here is a drawing.