DE102010010139A1 - Method for monitoring imprint on substrate, involves deriving signal from absorption measurement result for quality of imprints, and selecting measuring point depending on color saturation in imprints - Google Patents

Abstract

The method involves sending ultrasonic waves by a substrate (7) during transmission operation. The absorption measurement of the received sound level is performed. A signal is derived from the absorption measurement result for quality of imprints. A measuring point is selected depending on the color saturation in the imprints. The signal is utilized for controlling operation process of a machine producing the imprints. The signal is utilized for generating a warning signal, an adjusting signal for dryer (14) or a printing speed control signal.

Description

The The invention relates to a method for monitoring an imprint on a printing material according to the preamble of claim 1.

From the DE 43 21 179 A1 For example, a device for controlling or regulating operations of a printing press is known, which comprises an image pickup device which is directed onto the surface of a printed product. The signals reproducing a printed image are processed in a computer. As a result of this processing control signals are generated for a Farbdosiereinrichtung and an inspection of the substrate for material defects; like spots or holes. The computer also runs a program which identifies suitable measuring locations. The speed of image signal processing is limited. The camera optics used for image acquisition is susceptible to contamination.

It is still out of the DE 198 52 719 A1 It is known to monitor by means of ultrasonic detectors whether sheets of a printing machine are fed twice or more times and whether the sheets are damaged. A transmitter and a plurality of receivers are arranged on both sides of the sheet transport path. If a double arc occurs, the power of the sound waves at the receivers is strongly attenuated. The interfacial damping can be canceled locally by ink or fountain solution between the sheets. However, it is believed that adhesion between the generally unprinted sheets does not occur at multiple locations simultaneously.

The DE 692 16 043 T2 describes a device for ultrasonic testing of composite materials in which a plurality of focused ultrasound beams emanating from a test head have substantially the same angle of incidence on the surface of the material to be tested. If the composite material resting in water has a delamination, then additional characteristic echoes of the ultrasonic waves result. The arrangement of a plurality of ultrasonic sensor pairs is structurally complex. Signal processing is designed for testing on stationary DUTs. For a mapping of material defects, the test head can be moved only at low speed to the test object.

In the DE 10 2005 026 200 A1 a method for the detection of layered flat objects is described in which ultrasonic waves are transmitted through at least one object. When passing through the object, the ultrasonic waves are attenuated. For an arbitrarily thick, flat recording medium, the same signal level always results at an ultrasonic receiver. To monitor the quality of an object, multiple ultrasound transmitter-receiver arrays can be placed across the width of the object. The method may, for. B. be used to detect voids or delamination in paper webs. Due to the distance between the transceiver arrangements, the measuring locations are fixed to the object.

In a device for feeding sheets after the US 6,540,222 B2 a double feed is monitored in transmisson mode with an ultrasonic detector. Double-lying sheets are brought to a distance with a conveyor member. The air between the sheets causes a strong attenuation of emitted sound waves, so that the signal level at an ultrasonic receiver is significantly reduced.

The US Pat. No. 7,404,559 B2 shows an ultrasonic double-sheet control in transmission mode. The reception characteristics of an ultrasonic receiver are changed depending on the ambient temperature.

In DE-Z: Deutscher Drucker No. 38 / 22.11.2007 is described on page 15, that blistering at high ink layer thicknesses in web offset printing can be avoided by using moisture meters with measuring devices recorded online in paper rolls, in printed matter and in the pressroom and saved. If blistering occurs, the paper moisture can be brought to predetermined values.

task The invention is a method for monitoring a Develop printing on a substrate, which it with little effort allows to avoid blistering.

The Task is solved with a method which the features according to claim 1. Advantageous embodiments arise from the dependent claims.

According to the Invention monitors a print on a substrate, by sound waves through the substrate in the transmission mode be sent, and by damping the sound waves when passing through the substrate at at least one measuring location measured depending on the color saturation in the imprint becomes.

Especially It is advantageous to measure the attenuation at a measuring location with maximum color saturation. At this location the likelihood of blowing is greatest.

If the damping at the selected measuring location exceeds a limit, For example, a signal for controlling an operation of the imprint generating machine are generated. In particular, a warning signal or can control signals for a dryer and / or be derived for a printing speed actuator. The Invention is based on an embodiment closer be explained.

It demonstrate:

1 : A printing machine with an ultrasonic deflector in the transmission mode,

2 : a schematic of an ultrasound detector on a blistered arc,

3 : Level diagrams from absorption measurements with an ultrasonic detector, and

4 : a scheme for positioning an ultrasonic detector.

1 shows in schema an offset printing machine with an investor 1 , four printing units 2 to 5 and a boom 6 , The bows 7 promotional cylinders or drums are connected to a common gear transmission. A motor is used to drive the machine 8th and a gearbox 9 , At the drive shaft of the pressure cylinder 10 of the printing unit 3 sits a rotary encoder 11 , In the boom 6 there is a chain conveyor 12 for the bow 7 from the last printing unit 5 on a pile 13 , In the conveying path between the printing unit 5 and the pile 13 is a dryer 14 and an ultrasound detector 15 arranged. The motor 8th , the giver 11 , the dryer 14 and the detector 15 are with a control device 16 connected.

The bows 7 be in the investor 1 from a pile 17 isolated and in the printing units 2 - 5 with four part color pictures 18 - 21 ( 2 ) printed. While the bow 7 on the dryer 14 The part color pictures become 18 - 21 dried. The dryer performance is based on the conveying speed of the sheets 7 Voted.

The detector 15 consists of an ultrasonic sensor 22 and an ultrasound receiver 23 What's closer in 2 is shown. The detector 15 is transverse to the conveying direction 24 positionable. Depending on the print image is the detector 15 set to a position at which a print image area with maximum color saturation is detected. From the ultrasound transmitter 22 go with predetermined intensity sound waves 25 out, that's the bow 7 penetrate more or less. The sound waves 25 be through the ink of the part color images 18 - 21 and through the material the bow 7 steamed. The part of the sound waves 25 on the ultrasound transmitter 22 opposite side of a bow 7 is still present, is from the ultrasonic receiver 23 detected and in the control device 16 evaluated.

In the in 3 shown diagram two different receiver intensities IE1, IE2 are entered, which in an OK arc 7 and a bow 7 with blisters 26 occur in said print image area with maximum color saturation. In the OK sheet 7 is the ink of the part color images 18 - 21 firmly on the material of the bow 7 anchored. The intensity I _{E1 of} the sound waves at the ultrasonic receiver 23 is high and normalized in the diagram to 100%. Incorrect adjustment of the dryer performance 14 In areas with maximum color saturation, the ink dissolves from the sheets, leaving blisters 26 arise. The intensity I _E2 at the ultrasonic receiver 23 is greatly reduced in this case compared to the intensity I _E1 . If the intensity I _E falls below a predetermined threshold IES, then in the control device 16 Control signals for the dryer 14 and / or the engine 8th generated. The control signals cause blisters when they occur 26 reduces the dryer performance and / or reduces the machine speed. If a dryer 14 is used with partially controllable individual emitters, it is possible to reduce the dryer power automatically or by hand only where blister 26 occur. The appearance of blisters 26 can be announced optically or acoustically to a machine operator with a warning signal.

4 shows a scheme for positioning an ultrasonic detector 15 , The detector 15 is on a holder 27 attached. The holder 27 is with a motor across the conveying direction 24 on a frame-fixed traverse 28 positionable. The engine is connected to the control device 16 in connection. The data of the part color images 18 - 21 are prepress. By means of the data are stored in the control device 16 the coordinators (X ₁ , Y ₁ ) of a suitable measuring location 29 calculated and generated control signals for the motor. The motor drives the holder 27 automatically to the y-coordinate y1 of the measuring location 29 , The ultrasound receiver 23 of the detector 15 is determined by the signals of the encoder 11 , activated exactly when the place of measurement 29 within the coverage of the recipient 23 lies.

1

investor

2-5

printing unit

6

boom

7

bow

8th

engine

9

transmission

10

pressure cylinder

11

encoders

12

chain conveyors

13

stack

14

dryer

15

detector

16

control device

17

stack

18-21

Color separation

22

ultrasonic transmitter

23

ultrasonic receiver

24

conveying direction

25

sound wave

26

Blister

27

holder

28

traverse

29

Measuring location

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4321179 A1 [0002]
• - DE 19852719 A1 [0003]
• - DE 69216043 T2 [0004]
• DE 102005026200 A1 [0005]
• - US 6540222 B2 [0006]
• - US 7404559 B2 [0007]

Claims (8)

Method for monitoring an imprint on a printing material, in which, in the transmission mode, ultrasound waves ( 25 ) through the substrate ( 7 ), in which an attenuation measurement of the received sound level (I _E ) is made, and in which from the attenuation measurement a signal to the quality of the imprint ( 18 - 21 ), characterized in that a measuring location ( 29 ) depending on the color saturation in the print ( 18 - 21 ) is selected. Method according to claim 1, characterized by a measuring location ( 29 ) with maximum color saturation. A method according to claim 1, characterized in that the signal for controlling an operating process of the imprint ( 18 - 21 ) generating machine is used. Method according to claim 3, characterized that the signal is used to generate a warning signal. A method according to claim 3, characterized in that the signal for generating a control signal for a dryer ( 14 ) is used. Method according to claim 3, characterized that the signal for generating a Druckgeschwindigkeitsstellsignals is used. Method according to Claim 1, characterized in that the measuring location ( 29 ) from the imprint ( 18 - 21 ) is calculated. Method according to claim 8, characterized in that the printing material ( 7 ) relative to an ultrasound receiver ( 23 ), and that the receiver ( 23 ) transverse to the direction of movement ( 24 ) of the printing substrate ( 7 ) automatically over the measuring location ( 29 ) is positioned.