JPH0357650A - Printing state monitoring device of gravure printing - Google Patents

Abstract

PURPOSE:To make it easy to confirm a position for a print color mark for each print color and monitor the generation of printing misregistration by detection the density of each print color mark, the density of a printed image and the density of printing paper base using an analog light intensity detector, and displaying a differential waveform in comparison between a voltage value and a reference voltage. CONSTITUTION:A light intensity detector 3 detects the respective densities of a print color mark of a web paper 1 and a printed image 2. A differential output circuit 7 enters a density detection signal and generates a differential output for each color. An automatic reference voltage setting device consists of memory 8, a level check circuit 9 and a correction circuit 10. A comparator 13 compares a density detection signal which is output from a differential output circuit 7 with a reference voltage which is output from memory 8 through the correction circuit 10 to output a differential output. An amplifier 14 amplifies a current generated and an A/D converter 15 converts the amplified current to a digital signal. Buffer memory 16 stores the digital signal sequentially, and outputs the digital signal and displays its waveform on a CRT display device 19 through a CRT display signal processing circuit 18.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is an object of the present invention, in which the printing register state of each color of printing paper printed by a web rotary printing machine such as a gravure wear rotary printing machine is determined perpendicularly to the feeding direction of the wear printing paper. The present invention relates to a printing state monitoring device that detects printing color marks for each printing color arranged in a direction in which the printing color marks are arranged with an a degree detector, and monitors them based on the state of the detection timing.

(Prior art) Conventionally, in wear rotary printing, as a device for monitoring the print density of each printing color and the state of printing register during printing, as shown in FIGS. 4 and 5, On the front edge or rear edge of the printed image 2 printed continuously on the paper surface of the web printing paper 1 that is continuously printed on the paper and is fed out, there is a printed color mark (for example, Blue C, red M, yellow Y, black Bk 4
Color mark〉 for each cycle S each photo sensor 3
Concentration is detected by C, 3}1, 3Y, 38k,
The difference between the density detection signal and the base density (density of the printing paper surface) signal of the printing paper was obtained by differential calculation processing, and the obtained differential signal 4 for each color was output and displayed on a CRT display device or the like. The advantage of the detection method of printed color marks using differential processing is that even if the difference in color density between the base density of printing paper 1 and the printed color mark is small (especially when detecting pale yellow marks), it can be detected relatively clearly. A waveform can be obtained, and its print registration status can be monitored using an output display device such as a CRT display. However, since it is a differential waveform, it is difficult to distinguish at a glance the boundary between the waveform portion corresponding to the print color mark and the waveform portion corresponding to print image 2 among the waveforms for each color output to the output display device. There is. Therefore, if we take the detection of Y concentration as an example as shown in FIG. 7, we set the base Q voltage Vo in advance and use the concentration detection sensor to
By output processing the density analog signal 5, an analog output waveform Y1 of Y density can be obtained. And the waveform Y
1 is A/D converted and displayed on a CRT, the respective detection signal waveforms of the register mark and the print image 2 are displayed as a difference in length in the time axis direction, and can be easily identified. However, one disadvantage of analog signals is that it is fine if the printed color mark Y whose density is detected is Y1, which has a high density, but if it is Y2, which has a low density, the voltage level of the voltage Vo is not relatively lowered, so the seventh As seen in the analog output waveform Y2 in the figure, there are cases where the density value detected by the density detector of the printed color mark Y is below the reference voltage vO, resulting in a no-waveform area I3A6, and the printed color mark This will cause a problem in the detection accuracy of Y. Therefore, the question is how far the reference voltage VO can be lowered, or it is necessary to maintain it at least higher than the base density level of the printing paper itself.

(Object of the Invention) The present invention detects each printing color mark arranged in a direction perpendicular to the feeding direction of web printing paper using an analog detector, and monitors the printing registration state based on the detection timing. The detected waveform of the stamp image and the detected waveform are clearly displayed as a difference in length in the time axis direction, and the advantage of the analog waveform is that the two can be immediately distinguished. This is a printing condition monitoring device for gravure printing, etc., which incorporates the base density of print paper into the reference voltage setting.

(Structure of the Invention) The present invention provides an analog light amount detector that individually detects the density of each printed color of one to several printed colors, and the analog light amount detector or the detector that detects the base density of printed paper. A separate analog light amount detector, a reference voltage setter that sets a reference voltage based on the base density detection signal, a differential output circuit that differentially outputs the density detection signal for each color, and a differential output circuit for each color. a comparator that compares the dynamically output a degree detection signal and a reference voltage signal and outputs a differential signal as an analog signal; an amplifier that amplifies the differential signal; an A/D converter; and an output display signal @ processing circuit; This is a printing status monitoring device for gravure printing, etc., characterized by comprising an output display such as a CRT.

(Example) To explain the present invention in detail according to an example, FIG. 1 is a block diagram of the apparatus of the present invention, and each printing color mark (blue 2C, red M, yellow Y, black Equipped with light amount detectors 3 (3C, 3H, 3Y, 38k) such as a photosensor and a color density meter that respectively detect Bk}, as shown in Fig. 2 (
As shown in b), the printing color marks (C, M, Y, Bk> printed on the web printing paper 1 that is being printed and the printed image 2
A differential output circuit 7 is provided which detects the density of each color, inputs the density detection signal of each color from the detector 3, and outputs a differential signal for each color. On the other hand, each color mark (
A memory 8 that stores the detection signal level voltage of C, M, Y, Bk> and a memory 8 that stores the detection signal level voltage of
A reference voltage level check circuit 9 is provided for rewriting the voltage value stored in the memory 8 to the low voltage level data when a signal with a voltage level lower than the voltage value stored in the memory 8 is input. In this way, the lowest voltage level voltage V1 sent sequentially from the detector 3 is stored in the memory 8 by the check circuit 9. For the low voltage V1 stored in the memory 8, a predetermined voltage value (for example, a minute voltage value preset according to the smoothness of the printing paper used for printing and the type of printing ink) is used for reference voltage correction. A reference voltage correction circuit 10 is provided which applies a correction voltage (■) and outputs a reference voltage (V t+v=V o (reference voltage). It can be set according to the stability of the detection signal of the device 3.

The memory 8, level check circuit 9, and correction circuit 10 form an automatic base voltage setter. The detector 3 includes a constant voltage circuit 11 and a detector abnormal operation detection circuit 12. The density detection signal V of each print color mark and print image 2 output from the differential output circuit 7 for each print color is compared with the reference voltage VO output from the memory 8 via the correction circuit 10. , v-vo >o A comparator 13 that outputs a differential voltage (analog voltage), an amplifier 14 that amplifies the current generated by the differential voltage output from the comparator 13, and converts the amplified signal from the amplifier into a digital signal. It includes an A/D converter 15 for conversion, and a buffer 7 memory 16 for sequentially storing digital signals for each print color output from the converter 15. buffer 7 memory 1
Each signal stored in 6 is sequentially outputted and displayed by a timing generator 17 (timing circuit) to a CRT display device 19 via a CRT display signal processing circuit 18 in the form of a waveform as shown in FIG. Ru.

FIG. 3 explains the density detection processing for one stamp color of yellow Y, for example, and shows the detection waveforms at each depth of the high-density color mark Y1 and the low-density color mark Y2, and the printing at that time. The minimum voltage value v1 obtained from the paper base density and the correction voltage ■Vl +v = Vo
(Automatically set reference voltage)

(Operation of the Invention) The device of the present invention detects each printing color mark a degree, printing image@density, and printing paper base density printed in wear printing with an analog light amount detector, and The voltage value obtained based on the density detection signal and the density detection signal of the printing paper base, or by adding a correction voltage to it.
It compares the voltage with a reference voltage and displays the waveform of the difference on an output display device such as a CRT.It automatically detects the correct density by detecting the printing paper base density at the same time as detecting the density of the printed color mark and printed image. It is possible to obtain a good detection waveform that does not cause a waveform region and allows the printed color mark and the printed image to be distinguished at a glance.

(Effects of the Invention) In wear rotary printing such as gravure, the device of the present invention can output and display print color marks and print images for each print color in easy-to-monitor waveforms, and can output and display print color marks and print images for each print color. The difference in waveform from the image is displayed as a difference in length in the time axis direction, making it easy to confirm the position of the print color mark for each print color, making it easy to monitor the occurrence of printing misregistration, etc. It is effective.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the device of the present invention, Fig. 2 (a) is a plan view of wear-printed paper monitored by the device of the present invention, and Fig. 2 (opening) shows the output waveform output and displayed by the device of the present invention. A schematic diagram, FIG. 3 is a schematic diagram of detected waveforms processed by the apparatus of the present invention, and FIGS. 4 to 7 are conventional explanatory diagrams. 1. Web printing paper 2. Printed image 3...Detector 4...Differential waveform 5...Analog waveform 6
...No waveform area 7...Differential output circuit 8...Memory 9...Level check circuit 10...Correction circuit 11...Constant voltage circuit 12...Detector abnormality detection circuit 13 ...Comparator 14...Amplifier 15...
A/D converter 16...Buffer 17...Timing generator 18...Signal processing circuit 19...
CRT display

Claims (1)

[Claims] An analog light amount detector that individually detects the density of one to several printed colors, and an analog light amount detector that detects the base density of the printing paper, or an analog light amount detector separate from the detector. , a reference voltage setter that sets a reference voltage based on the base density detection signal, a differential output circuit that differentially outputs the density detection signal for each color, and a density detection signal that is differentially output for each color; A comparator that compares a reference voltage signal and outputs a differential signal as an analog signal, an amplifier that amplifies the differential signal, an A/D converter, and an output display signal processing circuit.
A printing status monitoring device for gravure printing, etc., characterized by comprising an output display such as a CRT.