JPH08159739A - Printing quality inspecttion device and method - Google Patents

Abstract

PURPOSE: To detect a failure even immediately after the failure occurs by registering the reference value of an inspection parameter, optical measuring a printing part, calculating the inspection parameter from the optical information, and comparing it with the reference value for judging comformity/nonconformity. CONSTITUTION: An automatic inspection mode is selected by an operation panel 5 and an inspection ID is selected and then the inspection is started automatically. A reference value is set at a parameter registration part 21. When automatic setting is selected, an inspection parameter is measured a specific number of times and the obtained data are averaged and then are directly registered in the case of the manual setting. A printed matter to be inspected is positioned at an inspection part 10 and the image is taken by a camera 3 which is an optical detection part 22. The image in the inspection window is binary-coded by an operation processing part 23 and noise objects are eliminated, thus obtaining the inspection parameter. Then, a processing part 23 compares it with a registered reference value and judges the conformity/nonconformity of the printing quality depending on whether the quality is within an allowable range or not. A measurement value and a judgment result are outputted to a monitor 5 for display and a printer 7 via an I/O part 24 and are outputted to an external printing machine controller 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print quality inspection apparatus and an inspection method, and more particularly to a print quality inspection apparatus and an inspection method for a magnetic printing unit which enable automation of a print quality inspection in a silk printing machine.

[0002]

2. Description of the Related Art Conventionally, for example, in the inspection of print quality of magnetic ink printing in a sheet-fed printing machine, an operator of the printing machine periodically extracts a sheet-like printed matter and dries it, and then prints the printed matter into a card-like shape. Then, the magnetic dynamic characteristics were measured by passing through a device such as a cutout card reader to judge the quality of the print quality.

Further, in the inspection of print quality in magnetic ink printing on a roll-shaped material, the printing machine is temporarily stopped at the time of inspection and a part of the printed material is cut into a card shape, or After placing a sheet-shaped original on the original and printing it, collect the sheet-shaped original and cut out a part of it into a card shape, then pass it through a device such as a card reader to measure the magnetic dynamic characteristics. Then, the quality of the print was judged.

[0004]

However, in the conventional print quality inspection as described above, there is a problem that the operator needs to constantly monitor the printing press, which imposes a heavy burden on the operator.

Further, since the inspection is an inspection by sampling, the inspection process is complicated and the time required for the inspection is long, and it is not possible to immediately detect the defective printing, and the printing yield is poor. there were.

Further, the printed matter that has been taken out and the magnetic dynamic characteristics of which have been measured by a device such as a card reader is cut off or damaged by the magnetic head and does not become a product and is discarded. Yield was coming down.

On the other hand, there is a magnetoresistive element (MR element) as a sensor for evaluating the dynamic characteristics of a magnetic pattern in a non-contact manner. However, since the resolution is insufficient and the magnetic pattern having a width of less than 1 mm cannot be evaluated, the barcode At present, it cannot be used for inspecting such a fine magnetic pattern.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to perform a non-contact inspection on a printing machine by optically measuring a printed matter, and immediately after a printing failure occurs, a failure occurs. It is an object of the present invention to provide a print quality inspecting apparatus and an inspecting method capable of detecting a print quality and greatly improving the print yield.

[0009]

In order to achieve such an object, a print quality inspection apparatus according to the present invention comprises a parameter registration section for registering a reference value of an inspection parameter and an optical detection for optically measuring a printed portion. Section and an operation processing section that calculates inspection parameters based on optical information from the optical detection section and compares the measured value of the inspection parameter with the reference value to determine pass / fail, the measured value and the operation. The configuration is such that the determination result in the processing unit is externally displayed or output, and the I / O unit to which the inspection timing signal is input is provided.

Further, in the inspection method of the present invention, the correlation between the printing complexity of the magnetic printing portion optically measured and the magnetic output of the magnetic printing portion, and the printing area of the magnetic printing portion optically measured. And the magnetic pattern width of the magnetic printing unit are preset, the printing complexity and the printing area of the magnetic printing unit are optically measured on the printing machine, and the magnetic properties of the magnetic printing unit are determined based on the correlation. The configuration is such that the quality of the output and the magnetic pattern width is determined.

[0011]

The printed matter to be inspected is optically measured in a non-contact manner by the optical detection unit, the arithmetic processing unit calculates the inspection parameter based on this optical information, and the inspection parameter registered in the parameter registration unit is calculated. The quality of the print quality is judged by comparing the reference value with the measured value of the inspection parameter, and the result of this judgment is displayed or output to the outside together with the measured value by the I / O unit. When the printed matter is a magnetic printing unit, printing is performed based on a preset correlation between the printing complexity of the magnetic printing unit and the magnetic output, and a correlation between the printing area of the magnetic printing unit and the magnetic pattern width. The quality of the magnetic output and the magnetic pattern width of the magnetic printing unit is judged from the printing complexity and the printing area of the magnetic printing unit optically measured on the machine.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the print quality inspection apparatus of the present invention, and FIG. 2 is a block diagram showing the configuration of the print quality inspection apparatus shown in FIG. 1 and 2, the print quality inspection apparatus 1 according to the present invention includes an image processing apparatus 2
And a camera 3 connected to the image processing device 2,
The image processing apparatus 2 includes an operation panel 5, a display monitor 6, and a printer 7. Further, the image processing apparatus 2 is connected to the printing press control unit 8 which is an external device. The image processing device 2 functions as the parameter registration unit 21, the arithmetic processing unit 23, and the I / O unit 24, and the camera 3 functions as the optical detection unit 22.

The image processing apparatus 2 as the parameter registration unit 21 has predetermined inspection parameters registered, and a reference value is set in advance for each inspection parameter, or an average is automatically obtained from the measurement results of several points. A value is obtained, and this value is set as a reference value and registered. The camera 3 as the optical detection unit 22 is for optically measuring the printed matter 11 in the printing press inspection unit 10, and usually includes a CCD camera 3a and an illumination 3b. As the illumination 3b, it is sufficient to select an illumination that provides an optical contrast between the base of the printed matter to be inspected and the print pattern, and for example, a ring fluorescent lamp or the like can be used. Further, the image processing apparatus 2 as the arithmetic processing unit 23 compares the measurement value obtained by calculating the inspection parameter with the optical information from the camera 3 and the reference value of the inspection parameter registered in the parameter registration unit 21. To determine whether the print quality is good or bad. Further, the image processing device 2 as the I / O unit 24 outputs the measured value and the determination result to the display monitor 6 and the printer 7, and outputs the determination result to the printing press control unit 8 which is an external device. Then, the inspection timing signal is input from the printing press control unit 8. This inspection timing signal is, for example, a signal for performing inspection at the timing when the vibration of the printed matter or the optical detection unit 22 due to the intermittent vibration associated with the reciprocating motion of the squeegee or the doctor peculiar to the silk printing machine is the smallest. The data is output from the / O unit 24 to the arithmetic processing unit 23.

The printing press inspection unit 10 can be provided between the printing unit and the drying unit of the printing press, or after the drying unit, and positions the printed matter 11 at a predetermined position and sucks and fixes it. Etc. can be arbitrarily set.

FIG. 3 is a flow chart showing the operating procedure for registration of inspection parameters in the parameter registration unit 21 of the print quality inspection apparatus 1 of the present invention. In FIG. 3, first, the parameter registration mode is selected on the operation panel 5, and the inspection ID is registered (or updated) (S-1 in FIG. 3).
Next, common parameters are set for the plurality of cameras 3 (two cameras are shown in FIG. 1) (S- in FIG. 3).
2). Here, whether to set the number of intervals for outputting the detection result of the camera 3 which is the optical detection unit 22 to the image processing apparatus 2 and automatically determine the threshold value for binarizing the detection result (discriminant analysis method). Is selected. In the above, when the automatic determination of the threshold is selected, the number of intervals for automatically updating the threshold is set. Further, after the printed matter 11 to be inspected is positioned in the printing press inspection section 10, the camera 3 is held until the printed matter 11 is securely held.
Set the delay time to delay the detection by.

On the other hand, in order to set parameters for each of the cameras 3, one camera is selected from the plurality of cameras 3 and whether or not to use the selected camera is designated first (see FIG. 3). S-3). When using the selected camera, parameters are set for each camera (S-4 in FIG. 3). Here, an inspection window as described later is set (S-5 in FIG. 3), and when the threshold for binarizing is fixed not automatically but in the above, the binary level is set (FIG. 3 S-6). In addition, multiple inspection parameters (area,
The width, pitch, perimeter, and complexity are specified (S-7 in FIG. 3), and the reference values are set for the inspection parameters specified for use, or automatically (measurement at several points). The average value is calculated from the values and used as the reference value) to set the number of times of averaging (the number of times of measurement for calculating the average value) (S-8 in FIG. 3). Further, the upper limit and the lower limit of the allowable value are set relatively to the above reference value (S-9 in FIG. 3).

FIG. 4 is a diagram showing an example of a print pattern to be inspected by the print quality inspection apparatus of the present invention. In the example shown in FIG. 4, the print pattern 12 printed on the printed matter 11 is formed by arranging four rectangular bars 13 having a predetermined width. Now, the inspectable area of the print pattern 12 is A1. On the other hand, when the printed matter 11 to be inspected is held at a predetermined position in the printing press inspection unit 10, it is necessary to allow an allowable value in the vertical direction and the horizontal direction for positioning the printing pattern. To do. In such a case, it is preferable that the above-mentioned inspection window is set as the area A2 which is inside the inspectable area A1 by the allowable values ΔX and ΔY. still,
The print pattern to be inspected is not limited to the bar shape.

Here, the print pattern 12 shown in FIG.
The inspection parameters (area, width, pitch, perimeter, complexity) will be described by taking as an example.

All the inspection parameters are binarized inspection objects (13a, 13a) in the inspection window A2.
Among b, 13c, and 13d (hatched areas in FIG. 4)), the average value, the maximum value, and the minimum value are obtained with respect to the inspection object excluding those that are in contact with the Y axis (13a and 13d). First, the print area as an inspection parameter is displayed by the number of pixels of the inspection object (13b, 13c). In addition, the print width is the X-axis fillet diameter, and
b, 13c), the maximum width in the X-axis direction is the print width. Further, the printing pitch is the center-of-gravity interval of each inspection object (13b, 13c) whose area is obtained, and the print perimeter is the length of the boundary pixel between each inspection object (13b, 13c) and the base. If the boundary line is not a straight line, it can be obtained by linear interpolation. The print complexity is obtained by substituting the print area S and the print perimeter L into the formula (L ² / S).

Next, the operation of the print quality inspection apparatus of the present invention will be described with reference to FIG. FIG. 5 is a flow chart showing the operation of the print quality inspection apparatus 1 of the present invention. The inspection is automatically performed by selecting the automatic inspection mode on the operation panel 5 and selecting the inspection ID (S-1 in FIG. 5). Is started (S-2 in FIG. 5). Next, the above parameter registration unit 2
When the reference value of the inspection parameter is automatically set in 1, the inspection parameter is first measured (S-3 in FIG. 5) the number of times corresponding to the specified averaging number and the average value is set as the reference value. (S-4 in FIG. 5). This reference value can be updated according to the interval set by the parameter registration unit 21, but normally, the reference value automatically set immediately after the start of printing is maintained as it is. In addition, when the reference value of the inspection parameter is set in the above-mentioned registration of the inspection parameter (when the reference value is fixed, not automatically), this step is unnecessary.

Next, after the printed matter 11 to be inspected is positioned in the printing press inspection section 10, the image to be inspected is taken in by the camera 3 which is the optical detection section 22 and stored in the memory (S in FIG. 5). -5). Then, the arithmetic processing unit 23 binarizes the image in the inspection window to remove noise objects, and performs labeling (in the example of FIG. 4, 13a, 13b, 13c, and 13d in this order) while performing inspection, Inspection objects that are not in contact with the Y axis (13b and 13c in the example of FIG. 4)
Then, the inspection parameter is measured (S-6 in FIG. 5). Further, the arithmetic processing unit 23 compares the reference value of the registered inspection parameter with the measured value of the inspection parameter, and determines whether the measured value is within the range of the allowable value registered in the parameter registration unit 21. Then, the quality of the print quality is judged (S-7 in FIG. 5).

Thereafter, the I / O unit 24 outputs measured values and judgment results to the display monitor 6 and the printer 7,
Further, the determination result is output to the printing press control unit 8 which is an external device. After that, the above steps (S-5) to (S-8) are repeated, and the inspection is completed when the printing is completed (S-9).

The print quality inspection apparatus of the present invention as described above is
Since the printed matter is measured optically, it is possible to perform non-contact inspection on the printing machine, which eliminates the conventional inspection time and machine stoppage such as sample preparation and sample measurement on the measuring machine. When a printing failure occurs, it can be detected immediately, and the printing yield can be greatly improved. Further, by outputting the inspection result to the display monitor 6 or the external printing press control unit 8, it is possible to accurately feed back to the operator or the printing press.
Furthermore, by automatically leaving the inspection history, it is possible to easily perform quality control of printed matter.

The inspection method of the present invention is to inspect the magnetic output from the printing complexity of the magnetic pattern and the bar width of the magnetic pattern from the printing area by the above-described print quality inspection apparatus of the present invention. Hereinafter, the inspection method of the present invention will be described.

FIG. 6 shows the measurement results (the number of measurements: 106 times) of the printing complexity by the print quality inspection apparatus of the present invention for each 6 shots of silk printing when a magnetic pattern (bar code pattern) is printed by silk printing. is there. Also, FIG.
Is the magnetic pattern for which the above printing complexity is measured,
It is the result of measuring the magnetic output. The magnetic pattern is printed with 28 prints of 4 × 7, and is located at each of four corners of imposition 1, imposition 4, imposition 25 and imposition 28 located at each corner of one printed matter. The printing complexity and the magnetic output of the magnetic pattern were measured. Figure 6
As shown in FIG. 7, the printing complexity increases with the lapse of time, while the change in magnetic output with time tends to increase gradually as shown in FIG.

Further, FIG. 8 shows the result of measuring the printing area by the printing quality inspection apparatus of the present invention for each 6 shots of silk printing when the magnetic pattern (bar code pattern) is printed by silk printing as in the above. : 106 times), and FIG. 9 shows the result of measuring the bar width of the magnetic pattern whose print area was measured. The bar width of the magnetic pattern is
The interval between signal peaks corresponding to both ends of one bar was defined as the bar width. As shown in FIG. 8, the print area decreases with time, and as shown in FIG. 9, the magnetic bar width also decreases with time.

The relationship between FIG. 6 and FIG. 7 described above, and FIG.
9 and FIG. 9, it is clear that the magnetic output correlates with the printing complexity and the bar width of the magnetic pattern correlates with the printing area. Therefore, for the magnetic pattern to be inspected, the correlation between the optically measured printing complexity and the electromagnetically read magnetic output, and the optically measured printed area and the electromagnetically read magnetic pattern width The correlation can be set in advance. The inspection method of the present invention is based on such a correlation,
Even if the magnetic pattern is not actually read electromagnetically, its shape is measured by an optical method, and the magnetic output and bar width of the magnetic pattern can be inspected on the printing machine immediately after printing to determine whether it is good or bad. is there. With such an inspection method of the present invention, it is possible to perform a non-contact inspection of the magnetic printing portion on the printing machine, and the magnetic printing portion can be inspected immediately after printing, so that even if a printing defect occurs, it can be detected immediately. can do.

[0029]

As described in detail above, according to the present invention, a non-contact inspection can be automatically performed on the printing press, and the operator does not need to constantly monitor the printing press, which reduces the burden. In addition, sampling for inspection, sample preparation, machine stoppage are eliminated, and even if a printing defect occurs, the defect can be immediately detected, so that the printing yield is greatly improved. However, non-contact inspection is possible, and the inspection history can be automatically recorded, so that quality control is facilitated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a print quality inspection apparatus of the present invention.

FIG. 2 is a block diagram showing a configuration of a print quality inspection device shown in FIG.

FIG. 3 is a flowchart showing an operation procedure of registration of inspection parameters in a parameter registration unit of the print quality inspection apparatus of the present invention.

FIG. 4 is a diagram showing an example of a print pattern as an inspection target of the print quality inspection apparatus of the present invention.

FIG. 5 is a flowchart showing the operation of the print quality inspection apparatus of the present invention.

FIG. 6 is a diagram showing a measurement result of a printing complexity of a magnetic pattern.

FIG. 7 is a diagram showing a result of measuring a magnetic output of a magnetic pattern whose printing complexity is measured.

FIG. 8 is a diagram showing a measurement result of a print area of a magnetic pattern.

FIG. 9 is a diagram showing a result of measuring a bar width of a magnetic pattern in which a print area is measured.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Print quality inspection apparatus 2 ... Image processing apparatus 3 ... Camera 5 ... Operation panel 6 ... Display monitor 7 ... Printer 8 ... Printing machine control section 21 ... Parameter registration section 22 ... Optical detection section 23 ... Arithmetic processing section 24 ... I / O section

Claims (3)

[Claims] 1. A parameter registration unit for registering a reference value of an inspection parameter, an optical detection unit for optically measuring a printed portion, an inspection parameter calculated based on optical information from the optical detection unit, and the inspection An arithmetic processing unit that compares the measured value of the parameter with the reference value to determine pass / fail, and externally displays or outputs the measured value and the determination result in the arithmetic processing unit, and receives an inspection timing signal I / O section, and a print quality inspection apparatus characterized by comprising. 2. A correlation between an optically measured printing complexity of the magnetic printing unit and a magnetic output of the magnetic printing unit, and an optically measured printing area of the magnetic printing unit and magnetic properties of the magnetic printing unit. The correlation with the pattern width is preset, the printing complexity and the printing area of the magnetic printing unit are optically measured on the printing machine, and the magnetic output of the magnetic printing unit and the quality of the magnetic pattern width are determined based on the correlation. An inspection method characterized by determining. 3. The inspection method according to claim 2, wherein magnetic printing is performed in a predetermined pattern on the multi-imposed dove portion, and the printing complexity and the printing area of the magnetic printing portion are optically measured. .