JP3609464B2 - Method and apparatus for setting reference mark detection position on web printed with pattern - Google Patents

Description

[0001]
[Industrial application fields]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for setting a reference mark detection position of a web on which a pattern is printed, and more particularly, a reference for obtaining a sampling timing of pattern data in a print position alignment in a web offset printing or a print quality inspection process. The present invention relates to a method and apparatus for setting a detection position of a mark.
[0002]
[Prior art]
A visible mark (alignment mark) is printed on the margin of the web as a reference mark in order to obtain the print data alignment timing in the web offset printing and the pattern quality sampling timing in the print quality inspection process. This is shown in the published patent publication (SHO 62-502601).
[0003]
Also, it is shown in the published patent publication (Japanese Patent Application Laid-Open No. 57-1766) that, using the pattern data printed on the web, a characteristic changed portion formed by the pattern data is extracted and used as a reference mark. Yes.
[0004]
[Problems to be solved by the invention]
Of course, if the fiducial mark is a specially printed visible mark, this fiducial mark has a distinctive feature point due to its mission, and of course the fiducial detection of the fiducial mark is ensured, however, In this case, it is necessary to print a visible mark, and the web needs a margin for printing the visible mark at an appropriate position.
On the other hand, when the characteristic change part made by the pattern data is used as the reference mark, there is no problem in the case of the visible mark, but how the characteristic change part made by the pattern data is extracted. The question remains about what to do.
[0005]
As a method for extracting the characteristic change portion, for example, a web picture pattern is optically scanned by a photoelectric conversion means such as an image sensor, a data sampling window is set, and the photoelectric conversion means outputs in accordance with the amount of received light. It is conceivable to monitor a change in the received light amount signal, and to make a change portion whose change amount is equal to or greater than a preset threshold value as a characteristic change portion. However, in this case, there is difficulty in optimal setting of the threshold value, and this threshold value needs to be set appropriately for each pattern pattern.
[0006]
Otherwise, the characteristic change part is not extracted, or the characteristic change part is set even if the change amount is small, and as a result, the detection position of the reference mark is detected due to a signal having a small S / N ratio. The setting becomes unstable and it becomes difficult to detect the reference mark reliably and reliably.
[0007]
The present invention has been made paying attention to the above-described problems. Regardless of the design pattern, the characteristic change portion of the design pattern is appropriately extracted to accurately detect the reference mark detection position on the web. Set the reference mark detection position of the web so that the detection of the reference mark can be performed reliably and reliably, and the print alignment and print quality inspection can be performed with high accuracy and stability. It is an object to provide a method and apparatus.
[0008]
[Means for Solving the Problems]
To achieve the above object, the reference mark detection position setting method of the web according to claim 1, repeat printing with a predetermined cycle determined one picture pattern to be printed by one rotation of the plate cylinder by the rotational speed of the plate cylinder In the method of setting the detection position of the reference mark on the formed web, the photoelectric conversion means optically scans the pattern pattern of the web, and the photoelectric conversion means outputs the received light amount signal output by the photoelectric conversion means according to the received light amount. Is stored in the storage means according to the scanning position set by the relative positional relationship between the image and the web, and the received light amount signal is increased or decreased with respect to the received light amount signal for one pattern pattern stored in the storage means. All the changing parts to be extracted, calculate the amount of change in the received light amount signal in all the changing parts, and calculate the amount of change in the received light amount signal in each changing part. It is compared to a reference mark the changing part the variation of the amount of change to extract the maximum change portion, of the reference mark storage addresses of the received light quantity signal is unique to give the intermediate point or midpoint point It is characterized by a detection position.
[0009]
To achieve the above object, a web of the reference mark detection position setting device according to claim 2, repeat printing with a predetermined cycle determined one picture pattern to be printed by one rotation of the plate cylinder by the rotational speed of the plate cylinder In a device that sets the detection position of the reference mark on the measured web, photoelectric conversion means that optically scans the web pattern and outputs a received light amount signal that changes according to the received light amount, and detects the amount of movement of the web A movement amount detection means for outputting a movement amount signal, and a storage means for storing the received light amount signal output from the photoelectric conversion means in accordance with the movement amount signal output from the web movement amount detection means. Then, all the changing portions where the received light amount signal increases or decreases are extracted from the received light amount signal corresponding to one picture pattern stored in the storage means, and all the changed portions are extracted. Calculating a change amount of the received light quantity signal, the change amount of the received light quantity signal at each change portions respectively compared to a reference mark the change amount is the greatest changes part of the amount of change, the midpoint of the change unit or Computational processing means is provided which uses the memory address where the received light amount signal giving the intermediate neighborhood point is unique as the reference mark detection position.
[0010]
[Action]
In the web reference mark detection position setting method according to the first aspect, the photoelectric conversion means optically scans the pattern pattern of the web to output a received light quantity signal corresponding to the received light quantity, and the received light quantity signal is the photoelectric conversion means. The memory means is stored with an address according to the scanning position data set by the relative positional relationship between the web and the web, and the received light amount signal of the received light amount signal for one pattern pattern stored in the storage means is increased or decreased. all changes section extracts for its in all change section calculates a change amount of the received light quantity signal, the change amount of the change amount of the received light quantity signal extracting maximum change portion at each change unit, the The change part is used as a reference mark.
[0011]
As a result, in one picture pattern, a change portion with the largest increase / decrease in the received light amount signal is extracted as a characteristic change portion and a reference mark is set, and a received light amount signal that gives an intermediate point or an intermediate vicinity point of this changed portion is obtained. The unique storage address is set as the detection position of the reference position mark.
[0012]
The web of the reference mark detection position setting device according to claim 2, in the photoelectric conversion means scans the web of picture pattern optically outputting a received light amount signal that changes according to the amount of light received, the web moving amount detecting means web The movement amount signal is output by outputting the movement amount signal, and the received light amount signal output by the photoelectric conversion means is addressed according to the movement amount signal output by the web movement amount detection means and stored in the storage means.
[0013]
The arithmetic processing means extracts all of the changing portions where the received light amount signal increases / decreases with respect to the received light amount signal for one pattern pattern stored in the storage device, and the amount of change of the received light amount signal in all the changed portions. The change portion with the maximum change amount among the change amounts of the received light amount signal in each change portion is used as a reference mark, and the storage address where the received light amount signal giving the intermediate point or the intermediate vicinity point of this change portion is unique. The detection position of the reference position mark.
[0014]
【Example】
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0015]
FIG. 1 shows an embodiment of a web print processing line to which a method for setting a reference mark detection position of a web according to the present invention is applied.
[0016]
One pattern is printed on the web W by one rotation of the plate cylinder 1, and the pattern is repeatedly printed with a predetermined cycle determined by the rotation speed of the plate cylinder 1. The web W on which the pattern pattern has been repeatedly printed is guided to the rollers 3 and 5 and sent to the next process section (not shown).
[0017]
A photoelectric sensor 7 that performs photoelectric conversion in the course of the traveling path of the web W and outputs an analog signal as a sensor signal (light reception amount signal) according to the amount of light received or reflected by the pattern pattern surface of the web W. Is fixedly arranged.
[0018]
A sensor signal output from the photoelectric sensor 7 is input to an arithmetic processing unit 9 by a computer system.
[0019]
The plate cylinder 1 is connected to a rotary encoder 11 that outputs a pulse signal each time the plate cylinder 1 makes one rotation. The roller 3 detects the amount of movement of the web W from the amount of rotation of the roller 3, and the roller 5. A rotary encoder 13 that outputs a pulse signal at every predetermined rotation angle is connected, and the pulse signals output by these rotary encoders 11 and 13 are input to the arithmetic processing unit 9 respectively.
[0020]
FIG. 2 shows a specific configuration example of the arithmetic processing unit 9. The arithmetic processing unit 9 includes an A / D converter 15 that converts a sensor signal from the photoelectric sensor 7 into a multi-value digital signal, and an input interface unit 17 that inputs a pulse signal from the rotary encoders 11 and 13. Yes.
[0021]
The input interface unit 17 outputs a pulse signal from the rotary encoder 11 to the encoder control circuit 19. The encoder control circuit 19 outputs a plate cylinder rotation detection signal by inputting a pulse signal from the rotary encoder 11, and the plate cylinder rotation detection signal is transferred from the encoder control circuit interface unit 21 to the CPU 25 through the bus line 23. .
[0022]
The CPU 25 is connected to a main memory 27, a RAM 29, and an output circuit 31 through a bus line 23. The CPU 25 inputs a plate cylinder one rotation detection signal and sends a reference mark detection start signal to the encoder control circuit interface unit 21. To the encoder control circuit 19.
[0023]
The encoder control circuit 19 outputs an address generation command to the address generation circuit 33 in response to the reference mark detection start signal from the CPU 25 and synchronizes with the input of the pulse signal from the rotary encoder 13 to the A / D converter 15. The D conversion operation and the writing of the A / D converted sensor signal to the memory 35 are controlled.
[0024]
The address generation circuit 33 generates a memory address indicating the scanning position for one rotation of the plate cylinder, that is, one picture pattern of the web W in synchronization with the input of the pulse signal from the rotary encoder 13, and the sensor signal in the memory 35. Set the write address of.
Thus, the sensor signal is scanned for each pulse of the pulse signal from the rotary encoder 13, in other words, the relative positional relationship between the photoelectric sensor 7 and the web W, in this case, the scanning set by the moving amount (traveling amount) of the web W. The address is assigned according to the position and written in the memory 35.
[0025]
When a sensor signal for one rotation of the plate cylinder is written in the memory 35, the CPU 25 accesses the memory 35, and the sensor signal for one rotation of the plate cylinder written in the memory 35, that is, a sensor for one picture pattern. In this embodiment, a change part where the sensor signal is increased or decreased is extracted from the signal, a change amount of the received light amount signal in the change part is calculated, and the change amount of the change amount of the received light amount signal in each change part is large. In the reference mark, the largest change part is used as a reference mark, and the memory address unique to the sensor signal that gives the intermediate point or the intermediate vicinity point of this change part and the level value (reference mark level value) of this sensor signal are output from the output circuit. The signal is output to the signal generation circuit 37.
[0026]
The reference mark signal generation circuit 37 sets a mark detection range by a window based on a memory address based on a memory address unique to a sensor signal that gives an intermediate point or an intermediate vicinity point of the changing portion, and a photoelectric sensor is used in the mark detection range. When the level value after A / D conversion of the sensor signal from No. 7 becomes the reference mark level value, the mark signal is output.
[0027]
Extraction of a change part in which the sensor signal increases or decreases changes after the sensor signal continues for a predetermined length in the scanning direction with a low level value, and then the sensor signal changes to a high level value. The low level value / high level value change part (increase change part) in the case of continuous over a predetermined length, or a sensor after the sensor signal has a high level value and continues over a predetermined length in the scanning direction. This is performed for the high level value / low level value changing portion (reduction changing portion) when the signal changes to a low level value and this low level value continues for a predetermined length in the scanning direction.
[0028]
Next, referring to the flowchart shown in FIG. 3 and the waveform diagram of the sensor signal shown in FIG. 4, the change position from the low level value to the high level value is extracted to set the reference mark detection position. A processing procedure will be described.
[0029]
First, the sensor signals are sequentially compared in the scanning direction to search for an increase start point a where the comparison value increases from a preset increase amount (steps 10, 20, and 30).
[0030]
If the increase start point a is searched, the next increase end point b where the level value of the sensor signal decreases is searched in the order of the scanning direction of the sensor signal (steps 40, 50, 60).
If the increase start point a → the increase end point b is searched, the 8 points before the increase start point a (the previous 8 points) are set as the sampling interval A, and the maximum value of the sensor signal is selected in the sampling interval A to the low level. Candidate L is extracted. Further, 8 points (hereinafter 8 points) after the increase end point b are set as the sampling section B, and the minimum value of the sensor signal is selected in the sampling section B to extract the high level candidate H (step 70).
[0031]
When the minimum mark width is 1 mm, if the pulse signal output period of the rotary encoder 13 is 0.125 mm in terms of the movement amount of the web W, the sampling interval of 1 mm is 8 points.
[0032]
The extraction of the high-level candidate H and the low-level candidate L is performed on all the changing portions from the low level value to the high level value of the sensor signal for one rotation of the plate cylinder written in the memory 35.
[0033]
When the above-described extraction of the high-level candidate H and the low-level candidate L is performed on the sensor signal for one rotation of the plate cylinder, then from the candidate group, (level value of the high-level candidate H) − (low-level candidate L Level value), that is, the high level candidate H and the low level candidate L of the change portion where the change amount d is maximum (step 80), {(level value of high level candidate H) + (low level candidate) L level value)} / 2 is performed (step 90), and a change portion where the change amount d is maximum is set as a reference mark, and an intermediate point m between the high level value and the low level value of the sensor signal at this change portion. Or the sensor address of the sampling point closest to the intermediate point m, in FIG. 4, the storage address unique to the sensor signal M is used as the reference mark detection position.
[0034]
Further, when the detection position of the reference mark is set by extracting the change part from the high level value to the low level value, the sensor signals are sequentially compared in the scanning direction, and the comparison value is less than a preset reduction amount. The reduction start point that is decreasing is searched, and then the reduction end point at which the level value of the sensor signal increases is searched in the order of the scanning direction of the sensor signal.
[0035]
If a decrease start point → decrease end point is searched, the sampling interval is set to the interval 8 points before the decrease start point and the interval 8 points after the decrease end point, and the sampling interval 8 points before the decrease start point. The minimum value of the sensor signal is selected to extract a high level candidate, and the maximum value of the sensor signal is selected in a sampling interval of 8 points after the end of the decrease to extract the low level candidate L.
[0036]
The extraction of the high-level candidates and the low-level candidates is performed on all the changing portions from the low-level value to the high-level value of the sensor signal for one rotation of the plate cylinder written in the memory 35.
When the above-described extraction of the high-level candidates and the low-level candidates is performed on the sensor signal for one rotation of the plate cylinder, the (high level candidate level value) − (low level candidate level value) is then extracted from the candidate group. Value, that is, a high level candidate and a low level candidate of a change part that maximizes the amount of change, and performs an operation of {(high level candidate level value) + (low level candidate level value)} / 2, The change part where the amount of change is the maximum is used as a reference mark, and the sensor signal that gives the midpoint between the high level value and low level value of the sensor signal at this change part, or the sensor signal at the sampling point closest to the midpoint is unique. The storage address to be used is set as the reference mark detection position.
[0037]
In fact, the process of setting the detection positions of the reference marks by extracting the change of the high level value than the low-level value, the detected position of the reference marks by extracting the change of the low-level value than the high level value The change part with the larger value of (high level candidate level value)-(low level candidate level value) is used as the final reference mark, and the middle of the change part. A memory address at which a sensor signal giving a point or a sensor signal at a sampling point closest to the intermediate point is unique is set as a reference mark detection position.
[0038]
As a result, regardless of the design pattern, the characteristic change part of the design pattern is appropriately extracted, the detection position of the reference mark on the web W is accurately set, and the detection of the reference mark is performed reliably and reliably. It becomes like this. As a result, printing alignment, print quality inspection, and the like can be performed with high accuracy and good stability.
[0039]
As another embodiment, the CPU 25 shown in FIG. 2 accesses the memory 35 when a sensor signal for one rotation of the plate cylinder is written in the memory 35, and makes one rotation of the plate cylinder written in the memory 35. For the sensor signal, that is, for the sensor signal for one picture pattern, the change part where the sensor signal increases or decreases is extracted, and the change amount of the received light amount signal in the change part is calculated in the same manner as in the above-described embodiment. Among the change portions, the change amount of the received light amount signal is a predetermined value or more, and the change portion in the scanning direction from the change start point to the change end point (change interval) is small. In this case, the sampling forming the change portion A change part with a small number of points, in this embodiment the smallest change part is used as a reference mark, and a memory address with which a sensor signal giving an intermediate point or an intermediate neighborhood point of this change part is unique, Level of the sensor signal (reference mark level value) may be output to the reference mark signal generating circuit 37 from the output circuit.
[0040]
According to this embodiment, the processing procedure for setting the reference mark detection position by extracting the changing portion from the low level value to the high level value is shown in the flowchart shown in FIG. 5 and the waveform of the sensor signal shown in FIG. This will be described with reference to the drawings. In the flowchart shown in FIG. 5, the same steps as those in the flowchart shown in FIG. 3 are denoted by the same step numbers as those in FIG. 3, and the description thereof is omitted here. Only the parts that differ from the flowchart shown in FIG.
[0041]
In this embodiment, when the extraction of the high level candidate H and the low level candidate L is performed on the sensor signal for one rotation of the plate cylinder, the (high level candidate level value) − (low level candidate) is next extracted from the candidate group. Level value), that is, the amount of change is not less than a predetermined value and the number of sampling points between the change start point a and the change end point b (the number of sampling points is 5 in the example of FIG. 4) is the smallest change. Part, in other words, the high level candidate H and the low level candidate L of the changing part having the maximum rate of change are selected (step 80), {(level value of high level candidate H) + (level value of low level candidate L) )} / 2 (step 90), a sensor signal that gives an intermediate point m between a high level value and a low level value of the sensor signal at the change portion, with the change portion having the smallest change interval as a reference mark, or Sampurin closest to midpoint m Sensor signal at point, the sensor signal M in Fig. 4 is the detected position of the reference mark unique to storage addresses.
[0042]
As a result, a portion where the amount of change is equal to or greater than a predetermined value and the rate of change is high and the sensor signal rapidly increases and changes is set as the reference mark. As a result, regardless of the design pattern, the characteristic change part of the design pattern is appropriately extracted, the detection position of the reference mark on the web W is accurately set, and the detection of the reference mark is performed reliably and reliably. Will come to be. As a result, printing alignment, print quality inspection, and the like can be performed with high accuracy and good stability.
[0043]
In this case as well, in practice, the process of setting the reference mark detection position by extracting the change part from the low level value to the high level value and the change part from the high level value to the low level value are extracted. Both of the processes for setting the detection position of the reference mark are performed, and among them, the change portion whose change amount is the predetermined value or more and the change interval is the minimum is set as the final reference mark, and an intermediate point of the change portion is given. The storage address where the sensor signal or the sensor signal at the sampling point closest to the intermediate point is unique is set as the reference mark detection position.
[0044]
Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited thereto, and various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.
[0045]
【The invention's effect】
As can be understood from the above description, according to the method and apparatus for setting the reference mark detection position of the web according to the present invention, a change portion with the largest increase / decrease in the received light amount signal is extracted as a characteristic change portion in one pattern. Since the reference mark is set, and the memory address where the received light amount signal that gives the intermediate point or the intermediate vicinity point of this changing portion is set as the detection position of the reference position mark, the reference mark is detected regardless of the pattern pattern. Thus, the characteristic change portion of the picture pattern is appropriately extracted, the detection position of the reference mark on the web is accurately set, and the detection of the reference mark is performed reliably and reliably. As a result, printing alignment, print quality inspection, and the like can be performed with high accuracy and good stability.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a web print processing line to which a web reference mark detection position setting method according to the present invention is applied.
FIG. 2 is a block diagram showing a specific configuration example of an arithmetic processing unit in a web reference mark detection position setting device according to the present invention;
FIG. 3 is a flowchart showing a processing procedure for extracting a change portion from a low level value to a high level value of a sensor signal and setting a reference mark detection position with a change portion having a maximum change amount;
FIG. 4 is an explanatory diagram illustrating a waveform example of a sensor signal.
FIG. 5 is a flowchart showing a processing procedure for extracting a change portion from a low level value to a high level value of a sensor signal and setting a reference mark detection position with a change portion having a minimum change interval.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plate cylinder 7 Photoelectric sensor 9 Arithmetic processor 11, 13 Rotary encoder 19 Encoder control circuit 25 CPU
33 Address generation circuit 35 Memory 37 Reference mark signal generation circuit

Claims (2)

Method for setting up a detected position of the reference marks of one of the picture pattern to be printed by one rotation of the drum to the web that is repeated printed with a predetermined cycle which is determined by the rotational speed of the plate cylinder,
The pattern pattern of the web is optically scanned by the photoelectric conversion means, and the received light amount signal output according to the received light amount by the photoelectric conversion means is determined by the scanning position set by the relative positional relationship between the photoelectric conversion means and the web. Address and store in the storage means, extract all the changing parts where the received light amount signal increases or decreases with respect to the received light quantity signal for one pattern pattern stored in the storage means, and in all the changing parts Calculate the amount of change in the received light amount signal, compare the amount of change in the received light amount signal in each change portion, extract the change portion having the maximum change amount from the change amount, and use this change portion as a reference mark, A reference mark detection position setting method for a web, characterized in that a storage address unique to a received light amount signal that gives an intermediate point or an intermediate vicinity point of the changing portion is set as a reference mark detection position. An apparatus for setting the detection position of the reference marks of one of the picture pattern to be printed by one rotation of the drum to the web that is repeated printed with a predetermined cycle which is determined by the rotational speed of the plate cylinder,
A photoelectric conversion means that optically scans a web pattern and outputs a received light amount signal that changes according to the received light amount;
A web movement amount detecting means for detecting a movement amount of the web and outputting a movement amount signal;
Storage means for storing the received light amount signal output from the photoelectric conversion means by addressing it according to the movement amount signal output from the web movement amount detection means;
Extracting all of the changing portions where the received light amount signal increases or decreases for the received light amount signal for one pattern pattern stored in the storage means, and calculates the amount of change of the received light amount signal in all the changed portions, The amount of change in the received light amount signal at each change portion is compared, and the change portion having the maximum change amount among the change amounts is used as a reference mark, and the received light amount signal that gives an intermediate point or an intermediate neighborhood point of this change portion is unique. An arithmetic processing means for setting a storage address to be a reference mark detection position;
A reference mark detection position setting device for a web.

Images