JP2003166940A - Signal tracking device for inspection apparatus for lithographic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a signal tracking device for an inspection apparatus for a lithographic material by which the processing time can be shortened and a low-cost system can be formed. <P>SOLUTION: The tracking device 60 is constituted so as to comprise a pointer register 62 and a plurality of tracking information registers 64 installed so a to correspond to each tracking length. A defect detection device 50, a label pasting device 42 and a movement-length measuring device 70 are connected. Each tracking length is set in advance according to the distance between the device 50 and the device 42 and a defect detection accuracy. Whenever a length- measuring pulse signal is output from the device 70, the pointer register 62 is incremented, information stored in each register 64 designated by the pointer register 62 is read out so as to be output to the device 42, and defect information which is newly detected by the device 50 is written. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal tracking device for a lithographic material inspection device, and more particularly to an inspection device for detecting a defective portion of a lithographic material such as a lithographic printing plate.
The present invention relates to a signal tracking device of a lithographic material inspection apparatus that performs signal tracking when a defective portion is detected and then the defective portion is identified.

[0002]

2. Description of the Related Art A photosensitive lithographic printing plate (hereinafter referred to as a lithographic printing plate) as a lithographic material is generally formed on a sheet-shaped or coil-shaped aluminum web, for example, by graining,
A surface treatment such as anodic oxidation, silicate treatment, and other chemical conversion treatment is carried out individually or in combination, and then a photosensitive solution is applied to form a photosensitive layer, which is then cut into a desired size.

Before proceeding to this cutting step, defects (streaks, scratches, coating unevenness, dust adhesion, etc.) on the photosensitive layer are detected by an optical defect detection device, and the planographic printing plate is used to identify the defects. A label is attached near the edge of. Then, the label is identified at the time of cutting and is rejected as a defective product.

Further, since the defect detection device and the label sticking device for discriminating the defective part are arranged apart from each other, the label sticking timing is controlled in order to stick the label to the defective part detected by the inspection device. (tracking)
Need to do.

Conventionally, when the tracking with a precision of 10 mm is performed for a distance of 30 m, the tracking has a length of 3000 shift registers and a length measuring device such as an encoder for measuring the moving length of the web and generating a pulse signal. As shown in FIG. 9, the defect detection result of the defect detection device 200 is stored in the register 202 by using the device, and all of the 3000 shift registers 202 are generated by the encoder 204, for example, in pulses generated in units of 10 mm. The data is sequentially shifted to sequentially label the label attaching device 206.
Tracking was realized by outputting to. In this case, in order to realize the tracking of the defective portion with an accuracy of 10 mm, if the moving speed of the web is 200 m / minute,
It is necessary to perform signal processing at msec intervals. Traditionally,
In order to constantly shift a large amount of data in a short time, a microcomputer (tracking computer 208) was used to create a program in machine language and operate the program.

[0006]

However, in the conventional tracking method, a large number of registers are required depending on the equipment specifications and the like, so that the processing time is required when all the information stored in the registers is shifted. There is a problem that it becomes longer depending on the number of registers.

Further, since the tracking as described above is performed using a dedicated tracking computer, there is a problem that the system becomes expensive.

The present invention has been made to solve the above problems, and provides a signal tracking device for an inspection device of a lithographic material which can shorten the processing time and can be an inexpensive system. The purpose is to

[0009]

In order to achieve the above-mentioned object, the invention according to claim 1 defines a length measuring means for measuring a moving length when the planographic material is conveyed and a defect of the planographic material is predetermined. Detection means for detecting with resolution, identification means for providing an identifier representing a defect on a lithographic material based on an input signal, and the distance between the detection means and the identification means and the resolution of the detection means are set in advance. A plurality of storage means for storing the detection result of the detection means, a designation means for designating any one of the storage means based on the movement length measured by the length measurement means, and Control means for outputting the detection result stored in the storage means designated by the designating means to the identifying means as the input signal, and then controlling the storage means so as to newly store the detection result of the detecting means. It is characterized in that it comprises.

According to the invention of claim 1, the length measuring means measures the moving length of the planographic material. For example, by using an encoder or the like, a predetermined pulse signal can be output along with the movement of the lithographic material, and the movement length when the lithographic material is conveyed can be measured by the pulse signal. Can be used as the length measurement signal.

The detection means may include a defect (eg,
Defects such as streaks, scratches, uneven coating, and dust adhesion) are detected. For example, it is possible to image the lithographic printing plate using a CCD line sensor or area CCD sensor and to detect the presence or absence of defects on the lithographic material from the image obtained as a result of the imaging.

The identifying means provides an identifier indicating that there is a defect on the planographic printing plate, for example, when the detection result indicates that a defect is detected, based on the input signal indicating the detection result by the detecting means. As the identifier, for example, a label or the like may be attached.

At this time, in order to give an identifier by the identifying means to the position on the planographic material where the defect has been detected by the detecting means, a plurality of positions for tracking the detection position by the detecting means and the position for providing the identifier by the identifying means are provided. Storage means is provided. That is, the plurality of storage means are provided in a preset number corresponding to the distance between the detection means and the identification means and the resolution of the detection means (for example, detection accuracy in the moving direction of the planographic printing plate). For example, if the distance between the detection means and the identification means is 30 m and the resolution of the detection means is 10 mm, 3000 storage means are provided. And
The storage means stores the detection result of the detection means.

Then, the designating means designates any one of the plurality of storage means based on the movement length measured by the length measuring means. For example, when the length measuring unit outputs a pulse signal in the resolution unit of the detecting unit, a plurality of storage units are designated in order every time one pulse is output from the length measuring unit. This makes it possible to specify the storage means in which the detection result of the detection means to be output to the identification means is stored.

Further, the control means outputs the detection result stored in the storage means designated by the designation means to the identification means as an input signal, and then stores the detection result newly detected by the detection means. Control the storage means.
That is, when the detection result detected by the detection means and stored in the storage means reaches the position where the identification means performs the identification, the detection result subsequently output by the identification means is output to the identification means. It is sequentially controlled by the control means so as to be stored in the storage means.

Therefore, the designating means sequentially designates the storage means in which the detection results to be output to the identifying means are stored, so that the setting is preset based on the distance between the detecting means and the identifying means and the resolution of the detecting means. Since the number storage means is provided, the defect detection by the detection means and the identification performed by the identification means can be tracked.

Thus, the detection results detected by the detection means and the identifier tracking performed by the identification means can be performed only by reading and writing the detection results in one storage means without shifting all the detection results stored in the plurality of storage means. Therefore, the time required for the tracking process can be shortened.

As the planographic material, a lithographic printing plate may be used as in the second aspect of the invention.

Further, the storage means, the designation means, and the control means can be configured by a programmable controller as in the invention described in claim 3, and by using a general-purpose programmable controller, an inexpensive system can be used. It is possible to build.

Further, as in the invention described in claim 4, the length measuring means generates the periodic pulse signal generated by the movement of the planographic material by the pulse signal generating means, and the frequency dividing means by the frequency dividing means. The pulse signal may be frequency-divided into a predetermined cycle, and the frequency-divided pulse signal may be shaped by the length measurement signal generation means so that the duty ratio becomes approximately 50%. That is, when the frequency of the pulse signal generated by the pulse signal generating means (for example, an encoder or the like) is very high, the time during which the pulse signal is on is very short, and the planographic material measured by the length measuring means is measured. It is possible that the moving length of the lithographic material cannot be detected by the specified means, but by forming the length measurement signal that represents the moving length of the lithographic material in this way, the on / off time is even and the on time is Since a long measuring signal can be generated, it is possible to detect a measuring signal representing the moving length of the lithographic material measured by the measuring means by the designating means.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, the present invention is applied to a lithographic printing plate inspection apparatus.

As shown in FIG. 1, a planographic printing plate inspection apparatus 40 according to the present embodiment includes a defect detection apparatus 50 (FIG. 5) as a detection means including a camera 12 for detecting a defective portion of the planographic printing plate 10. Reference) and a label sticking device 42 as an identification means for sticking a label to the defective portion. The planographic printing plate 10 is conveyed to the defect detection device 50 through the inspection roll 14 and the defective portion is detected. Then, it is conveyed to the label sticking device 42, a label is stuck on the defective portion, and it is wound around a roll 61 and conveyed to the cutting step.

The defect detecting device 50, as shown in FIG.
Six cameras 12 arranged in the width direction of the planographic printing plate 10.
And a defect portion (streak,
(Scratches, uneven coating, dust adhesion, etc.) are detected.

As shown in FIG. 1, the camera 12 is located above the inspection roll 14 and takes an image of the planographic printing plate 10 wound around the inspection roll 12. Also,
As shown in FIG. 3, a light source (for example, a fluorescent lamp) 16 covered with a yellow color filter 18 is arranged on the upstream side of the inspection roll 14 and irradiates the photosensitive layer of the lithographic printing plate 10 so as to be imaged. ing.

Further, the distance between the camera 12 and the planographic printing plate 10 is kept constant, and if the focus is adjusted at the time of installation, the subsequent focus adjustment is unnecessary. In addition, a yellow inspection light (for example, a wavelength 470) using a color filter is used.
The exposure of the photosensitive layer is prevented by irradiating (eg, light of ˜770 nm). The color filter 18 and the light source 16
Alternatively, a yellow fluorescent lamp may be used. Also,
The light source 16 that emits the inspection light is not limited to a fluorescent lamp, but may be a halogen lamp or a HIDL (High Intensi).
ty Discharge Lamp) or the like may be used.

Furthermore, by using different colors for the color filter 18, it is possible to change the cut wavelength range to enhance the exposure prevention property and change the illuminance.

A deflection filter 20 is provided in front of the camera 12 to cut the longitudinal wave of the inspection light specularly reflected by the surface of the photosensitive layer and make the transverse wave incident on the camera 12.

On the other hand, a label sticking machine 42 (see FIG. 1) is provided on the downstream side of the inspection roll 14. After the defect signal is output from the comparator 44 (see FIG. 5), the label sticking machine 42 sticks the label 24 on the edge of the planographic printing plate 10 at a predetermined timing controlled by the tracking device 60 described later. The label 24 is identified at the time of cutting and is rejected as a defective product. In addition,
The predetermined timing for attaching the label 24 is determined by the tracking process (details will be described later) performed by the tracking device 60.

As shown in FIG. 4, the camera 12 is provided with a lens 28 for forming an image on the CCD line sensor 26 in which an image in which the longitudinal wave of the specularly reflected light from the planographic printing plate 10 is cut is formed.

The CCD line sensor 26 is a lithographic printing plate 1.
2 photo detectors in the width direction of 0 (direction orthogonal to the transport direction)
There are 000 of them, and the reading range (visual field width) of one camera 12 is 260 mm. Therefore, the width resolution (detection range) is 260 mm / 2000 bit = 0.1.
3 mm (defects such as scratches of this width can be detected). It should be noted that even a defect such as a scratch having a width narrower than 0.13 mm can be detected if the semi-light-shielding amount of the scratch is sufficiently large. The resolution of the planographic printing plate 10 in the moving direction is determined by the moving speed of the planographic printing plate 10.
The moving speed is set to have a resolution of mm.

Further, as shown in FIG. 2, the inspection device 40 according to the present embodiment is configured such that six cameras 12 having a camera field of view of 260 mm cover a range of 1500 mm. The CCD line sensors 26 are arranged so that the image of one line in the width direction of the planographic printing plate 10 is viewed, and one CCD line sensor 26 is provided at both ends of the adjacent CCD line sensors 26.
Since there is a 0 mm overlap, the image signal at the edge portion is canceled in signal processing.

On the other hand, the camera 12 reads the amount of incident light at a constant cycle. The constant cycle is, for example, a unit of storage time for storing the signal charges obtained by converting the light entering from the opened light entrance window as the stored data every 0.2 seconds, and the transport speed of the planographic printing plate 10 is Within the set range, the planographic printing plate 10 can be detected without omission at any transport speed.

Next, a signal charge processing system for processing the signal charges output from the camera 12 will be described.

The camera 12 is, as shown in FIG.
The signal charges connected to the converter 30 and output from the CCD line sensor 26 are input to the A / D converter 30. A
In the / D converter 30, the signal charge is converted from an analog signal to a digital signal.

The output of the A / D converter 30 is connected to the signal processing circuit 34. In the signal processing circuit 34, signal processing such as adjacent correlation processing is performed to reduce the noise portion and to make the defective signal portion stand out.

The output of the signal processing circuit 34 is connected to the comparator 44. In the comparator 44, the sensitivity level value for the defective portion is set, and the set sensitivity level value and the signal processed by the signal processing circuit 34 are compared to determine whether the defect signal is a preset sensitivity level or higher. It is configured to determine whether or not to output the comparison result. For example, the comparison result by the comparator 44 outputs 1-bit information, and "0" indicates no defect, "1" indicates defect, and the comparison result is output.

By the way, the arrangement of the defect detection device 50 and the arrangement of the label sticking device 42 for sticking a label to the defective portion detected by the defect detection device 50 are separated from each other. In order to attach a label to the detected defective portion, it is necessary to control the operation timing of the label attaching device 42, that is, the output timing of the defect information detected by the defect detecting device 50. Therefore, in the present embodiment, the defect detection device 5
As shown in FIG. 6, a tracking device 60 as a control means is provided in order to control the timing for applying a label to the defective portion detected by 0 by the label applying device 42.

The defect detecting device 50 and the label attaching device 42 described above are connected to the tracking device 60.
Further, a moving length measuring device 70 as a length measuring unit for measuring the moving length of the planographic printing plate 10 is connected.

The moving length measuring device 70 includes a measuring roll 72,
It is composed of an encoder 74 as a pulse signal generating means, a frequency divider 76 as a frequency dividing means, and a pulse waveform shaping circuit 78 as a length measuring signal generating means. The length measuring roll 72 is a planographic printing plate 10 or an inspection. It is provided in contact with the roll 14 and is rotated as the lithographic printing plate 10 moves. The length measuring roll 72 is provided with an encoder 74, and the encoder 74
Thus, the moving length of the planographic printing plate 10 is measured. The encoder 74 generates a predetermined pulse by the rotation of the length measuring roll 72.

The frequency divider 76 frequency-divides the pulse signal output from the encoder 74 according to the detection accuracy of the defective portion,
Generate pulses at predetermined intervals.

The pulse waveform shaping circuit 78 detects a rising pulse by, for example, a flip-flop, and measures the pulse signal divided by the frequency divider 76 so that the duty ratio of the pulse signal becomes approximately 50%. Generate a pulse signal.

Further, as shown in FIG. 6, the tracking device 60 comprises a pointer register 62 as a designation means and a tracking information register 64 as a storage means.

A plurality of tracking information registers 64 are provided according to a preset tracking length.
The tracking length is the distance between the defect detection device 50 and the label sticking device 42, and the detection accuracy of the defective portion (the defect detection device 5
It is set in advance corresponding to (0) resolution in the moving direction of the planographic printing plate 10. For example, when the distance between the defect detecting device 50 and the label sticking device 42 is 30 m and the detection accuracy of the defective portion is 10 mm, the tracking information register 64 is used.
Requires 3000 pieces, and the tracking length is 3000
Becomes The tracking length can be arbitrarily set by the tracking length setting 66. As described above, the tracking length is set by the resolution (detection accuracy) of the defect detection device 50, the label sticking device 42, and the defect detection device. It is set corresponding to the distance between 50.

The pointer register 62 provided in the tracking device 60 is the tracking information register 6
4 acts as a pointer for reading and writing data. That is, the pointer register 62 specifies the address of the tracking information register 64 for reading and writing. For example, as in the above example, the tracking length is 3
000, the pointer register 62 has 1 to 30
The tracking information register 64 of 00 is sequentially designated.

The tracking device 60 is composed of a general-purpose programmable controller.

Next, the detection of the defective portion of the planographic printing plate 10 in the inspection device 40 configured as described above will be described.

First, the inspection light specularly reflected by the planographic printing plate 10 has its longitudinal wave cut by the deflection filter 20 and its transverse wave incident on the lens 28. Then, an image is formed on the CCD line sensor 26.

As described above, by cutting the longitudinal wave, it is possible to reduce the noise on the normal surface other than the defect signal due to a slight scratch or the like.

As described above, the signal output from the CCD line sensor 26 is converted into a digital signal by the A / D converter 30 and digitized, and the signal processing circuit 34 performs adjacent correlation processing to generate a noise portion. Is reduced and the part of the defect signal becomes more prominent, and only continuous defect signals can be emphasized.

Then, the comparator 44 compares the signal processed by the signal processing circuit 34 with the preset sensitivity level value, and the comparison result is output to the tracking device 60.

The operation of the defect detecting device 50 is performed as described above. In the present embodiment, however, the defect detecting device 50 is operated.
The defect detection device 50 and the label sticking device 42 operate while performing the tracking process depending on the distance between the label sticking device 42 and the label sticking device 42.

Next, FIG. 7 shows the tracking process.
This will be described with reference to the flowchart in FIG.

First, when the power is turned on, in the tracking device 60, the pointer register 62 in step 100.
Value P and the information T in the tracking information register 64 are initialized.

Next, at step 102, it is judged whether or not the length measuring pulse has been input to the tracking device 60 from the movement length measuring device 70. That is, the moving length measuring device 70
Then, as the planographic printing plate 10 is moved, the encoder 74 is driven via the length measuring roll 72, as shown in FIG.
A pulse signal (encoder output) as shown in is generated and frequency-divided by the frequency divider 76, and the pulse waveform shaper 7
8, the length measurement pulse signal is shaped. Then, the length measurement pulse signal is input to the tracking device 60.
In step 102, it is determined whether or not the length measurement pulse signal is input to the tracking device 60, and the process waits until the determination is positive. It should be noted that one length measurement pulse is generated in units of defect detection accuracy.

If the determination in step 102 is affirmative, the process proceeds to step 104 and the pointer register 62
The information in the tracking information register corresponding to the value of is read and output to the label sticking device 42. At this time, in the label sticking device 42, if there is a defect based on the defect information (for example, 1-bit information) output from the tracking information register 64, the defect information is the label sticking device 4
A label is attached to the planographic printing plate 10 at the timing of inputting 2. As a result, the label is attached to the defective portion.

In step 106, the pointer register 6
The defect information obtained from the defect detection device 50 is written in the tracking information register 64 corresponding to the value of 2.

That is, after the defect information is read from the tracking information register 64 designated by the pointer register 62, the subsequent defect information is written.

Subsequently, at step 108, the value P of the pointer register 62 is incremented, and at step 11
The process proceeds to 0, and it is determined whether the value P of the pointer register 62 is larger than the preset tracking length X. When the determination is affirmative, the process proceeds to step 110, the value of the pointer register 62 is returned to the initial value (for example, 1), the process returns to step 102, and the above-described processing is sequentially repeated.

On the other hand, if the determination in step 110 is affirmative, the process directly returns to step 102 and the above-described processing is repeated.

As described above, when the length measurement pulse signal is input, the information stored in the tracking information register 64 designated by the pointer register 62 is read and output to the label sticking device 42, and then the defect detecting device. Since the defect detection information of the planographic printing plate 10 newly detected by 50 is written, the defect detection device 50 and the label sticking device 4
If the numerical value of the tracking information register 64 for the distance from 2 (the setting value of the tracking length 66) is set, the defect detected by the defect detection device 50 without shifting the information in all the tracking information registers 64. A label can be attached to the position by the label attaching device 42.
Therefore, unlike the conventional case, it is not necessary to shift all the information stored in the shift register at once, so that the processing time required for the tracking processing can be shortened.

For example, 3 tracking with 10 mm accuracy
Description will be given taking as an example a case where the operation is performed for a distance of 0 m. At this time, assuming that the encoder 74 outputs 20 pulses at a movement of the lithographic printing plate 10 of 10 mm, if the division cycle 76 is divided into 1/10, each time the lithographic printing plate 10 moves by 10 mm. A one-pulse length measurement pulse is output.

Since it is necessary to hold defect information for 30 m of the planographic printing plate 10, the tracking length is 30.
If 00 is set, the defect information for 30 m can be held with an accuracy of 10 mm.

First, when the measurement pulse is input,
For example, the information designated by the pointer register 62 and stored in the first tracking information register 64 is read by the label sticking device 42. Note that there is no data stored in the tracking information register 64 because the distance between the camera 12 and the label sticking device 42 is 30 m at the beginning.

At the same time, the defect information detected by the camera 12 is written in the read tracking information register 64, and the value of the pointer register 62 is incremented. In this case, the second tracking information register 64 is incremented to a value that specifies it. Then, each time a length measurement pulse is input, the information stored in the tracking information register 64 designated by the pointer register 62 is read to read the label sticking device 42.
At the same time, the defect information detected by the camera 12 of the defect detection device 50 is written in the tracking information register 64 designated by the pointer register 62.

Then, when the length measurement pulse for 30 m, that is, the length measurement pulse of 3000 is input, the detection information actually detected by the camera 12 of the defect detection device 50 is output to the label sticking device 42. become,
This enables tracking of 30 m.

When the length measurement pulse of 3001 is input, the pointer register 62 is initialized because it exceeds the tracking length setting value. That is, 3001
When the second length measurement pulse is input, the pointer register 6
2 returns to a value designating the first tracking information register 64, and tracking is performed by sequentially performing the same processing as above.

That is, the tracking information registers 64 required for the distance for tracking are prepared, and the pointer register 62 sequentially rotates the tracking information registers for 1 to the tracking length set value to obtain the desired tracking. Long tracking can be performed. Therefore, since the shift register does not shift the information stored in all the registers, the information is sequentially read from and written to one tracking information register 64. Therefore, the processing time is shortened as compared with the conventional case where the shift register is used for tracking. Can be significantly shortened. And even if the tracking length becomes long, it can be dealt with simply by changing the tracking length setting value,
Since the processing time is only the time for reading / writing one tracking information register 64, it is possible to perform tracking with a constant processing time regardless of the tracking length.

The length measurement pulse signal is sent to the encoder 7
If only the output of No. 4 is used, as in the encoder output shown in FIG. 8, the pulse signal is on for a short time and the response time by the tracking device 60 cannot be secured, but in the present embodiment, , The pulse waveform shaper circuit 78 shapes the length measurement pulse signal having a duty ratio of about 50% after frequency division by the frequency division cycle 76.
It is possible to generate a length measurement pulse signal capable of ensuring a response time by

Further, the tracking device 60 can be realized by a microcomputer, but in the present embodiment, an inexpensive system can be constructed by using a general-purpose programmable controller.

In the above embodiment, the inspection device for the lithographic printing plate has been described as an example, but the inspection device is not limited to the lithographic printing plate, and any inspection device for handling lithographic material can be used.
The present invention can be applied.

[0071]

As described above, according to the present invention, the distance between the detecting means for detecting a defect of the planographic material and the identifying means for giving an identifier to the defective portion and the resolution of the detecting means are set in advance. By specifying any one of the plurality of storage means provided, and outputting the detection result stored in the specified storage means to the identifying means, and then storing the detection result. Without shifting all the detection results stored in the storage means, detection by the detection means and tracking of the identifier performed by the identification means can be performed only by reading and writing the detection results in one storage means. There is an effect that the time required for the processing can be shortened.

Furthermore, since a general-purpose programmable controller can be used, there is an effect that an inexpensive system can be constructed.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing a lithographic printing plate inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a front view of the lithographic printing plate inspection apparatus according to the embodiment of the present invention.

FIG. 3 is a side view showing a lithographic printing plate inspection apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram showing a CCD line sensor of a lithographic printing plate inspection apparatus according to an embodiment of the present invention.

FIG. 5 is a block diagram showing a signal charge processing system in a lithographic printing plate inspection apparatus according to an embodiment of the present invention.

FIG. 6 is a block diagram showing a tracking device in the lithographic printing plate inspection apparatus according to the embodiment of the present invention.

FIG. 7 is a flowchart showing tracking processing in the lithographic printing plate inspection apparatus according to the embodiment of the present invention.

FIG. 8 is a diagram showing an encoder output, a frequency divider output, and a pulse waveform shaper output.

FIG. 9 is a diagram showing a tracking device in a conventional lithographic printing plate inspection device.

[Explanation of symbols]

10 planographic printing plates 42 Labeling device 50 defect detector 60 Tracking device 62 Pointer register 64 Tracking information register 66 Tracking length setting 70 Moving length measuring device 72 Measuring roll 74 encoder 76 divider 78 Pulse waveform shaping circuit

Claims (4)

[Claims] 1. A length measuring means for measuring a moving length when a planographic material is conveyed, a detecting means for detecting a defect of the planographic material with a predetermined resolution, and a defect on the planographic material based on an input signal. Identification means for applying an identifier, a plurality of storage means provided with a preset number corresponding to the distance between the detection means and the identification means and the resolution of the detection means, and storing the detection result of the detection means A designation unit that designates any one of the plurality of storage units based on the movement length measured by the length measurement unit; and a detection result stored in the storage unit designated by the designation unit as the input signal A signal tracking device of a lithographic material inspection apparatus, comprising: a control means for controlling the storage means so as to newly store the detection result of the detection means after outputting to the identification means. 2. The signal tracking device of the lithographic material inspection device according to claim 1, wherein the lithographic material is a lithographic printing plate. 3. The signal tracking device for a planographic material inspection apparatus according to claim 1, wherein the storage means, the designation means, and the control means are composed of a programmable controller. 4. The length measuring unit divides the pulse signal generated by the pulse signal generating unit into a predetermined period, the pulse signal generating unit generating a periodic pulse signal according to the movement of the planographic printing plate. It comprises frequency dividing means for performing frequency division, and length measurement signal generation means for generating a length measurement signal by shaping a waveform so that the duty ratio of the pulse signal frequency-divided by the frequency division means is approximately 50%. A signal tracking device for a planographic material inspection device according to any one of claims 1 to 3.