JP4228616B2 - Defect detection method for printed matter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printed matter defect detection method for inspecting defects in a sheet-like printed matter in which the same pattern is continuously printed on successive sheets.
[0002]
[Prior art]
There are various printing methods, but there is a gravure printing method as one of methods for continuously printing sheet-like printed matter.
For example, as shown in FIG. 3, a printing press that employs a gravure printing method includes a sheet feeding unit (2), a dancer roller unit (3), a printing drying unit (4), a cutting unit (5), and the like. It consists of an array configuration.
[0003]
FIG. 4 shows an outline of the print drying unit (4) of FIG. That is, the web (1) passes between the gravure cylinder (6) and the impression cylinder (7) so that a desired pattern is printed, dried, and discharged as a sheet-like printed material (10).
[0004]
When printing, dust marks such as paper dust and ink splashes occur outside the range of the pattern that will be the product (11) in the printed sheet or outside the range of the pattern that is not the product (12). In this case, the dust mark becomes a defect (13), and a defective product becomes a defective product (see FIG. 1).
[0005]
For this reason, it is necessary to remove the defective sheet-like printed matter in advance so as not to mix this defect (13) into the product.
Defect detection work is performed simultaneously with printing using a pattern inspection machine, and the entire paper is the inspection target.
[0006]
The inspection method is as follows, for example.
That is, as shown in FIG. 2, the same picture is printed, and is generated in a sheet-like printed matter (10) formed by continuously printing frames having a width (W) and a length (L) in the flow direction. When a pattern inspection machine for detecting a defect (13) to be detected is considered, the frame is divided into m × n inspection areas having an area of W / m × L / n, and the m × n inspection areas for each frame. Are sequentially selected one by one and imaged, and a pattern comparison between the image of each inspection region and a reference image corresponding to the image is performed, and a defect is determined from the result.
[0007]
As described above, since the pattern inspection machine inspects the entire surface of the sheet-like printed matter (10) including the part that does not enter the final product, the defect (13) that appears on the part outside the product is also judged to be defective. This has caused the yield to decrease, such as the need for a removal step.
[0008]
On the other hand, in the gravure cylinder (6), as shown in FIG. 2, a number of patterns are continuously formed on the basis of the pattern of one rotation of the cylinder. Cannot be evaluated.
The inspection start position is set at a random position according to the input timing of the inspection start signal.
The pattern position has printing accessories (marks, etc.) on both sides of the printed material, and can be specified in relation to the position. In addition, a cutting dragonfly is included in an object to be cut.
[0009]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above-described problems relating to the pattern inspection method for sheet-like printed matter in which the same pattern is continuously printed on continuous sheets, and an inspection method for inspecting only a product portion. It is an issue to provide.
[0010]
[Means for Solving the Problems]
In the invention of claim 1 of the present invention, each frame of a continuous sheet-like printed matter formed by continuously printing frames having a width (W) in which the same pattern is printed and a length (L) in the flow direction, The inspection region having an area of (W / m) × (L / n) is divided into m × n, and the m × n inspection regions are selected one by one for each frame and imaged. When a pattern is compared between an image of a region and a reference image corresponding to the image and a defect is determined from the result, a part outside the product is defined as a non-inspection area, and any address within the m × n division is outside the inspection area A defect detection method for a printed matter in which addresses outside the area are excluded from inspection targets and defects generated in the sheet-like printed matter are detected. Machining on the basis of grooves, printing cylinder drive Recognize the cylinder allocation reference by the keyway position of the unit, match the reference image with the cylinder allocation of the pattern, and set an out-of-pattern mask area to exclude the address of the non-inspection area from the inspection target, A defect detection method for printed matter, characterized by detecting defects generated in a sheet-like printed matter .
[0011]
As described above, according to the first aspect of the present invention, since the portion outside the product is masked and only the product portion is inspected, the portion outside the product is excluded from the inspection target, the removal process is eliminated, and the yield is increased. improves.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The printed matter defect detection method of the present invention will be described in detail below based on an embodiment.
The printed matter defect detection method of the present invention is, for example, as shown in FIGS. 1A and 1B, detecting defects in a sheet-like printed matter (10) in which the same pattern is continuously printed on successive sheets. In this method, the part (12) outside the product is masked (14) to inspect only the product part (11).
[0013]
Here, an example of a specific method of mask processing will be described.
That is, the defect (13) generated in the sheet-like printed matter (10) formed by printing the same pattern on the width (W) and continuously printing the length (L) in the flow direction is detected. When considering a pattern inspection machine, the frame is divided into m × n inspection areas having an area of W / m × L / n, and the m × n inspection areas are sequentially selected one by one for each frame. Images are taken and pattern comparison is performed between the image of each inspection region and a reference image corresponding to the image, and a defect is determined from the result (see FIG. 2).
[0014]
At this time, an address outside the inspection area is evaluated at which address in the m × n division, and an address outside the area is excluded from the inspection target and the inspection is attempted.
[0015]
On the other hand, in order to set the non-picture mask area, it is necessary to recognize the area and to recognize the picture position within the area, and therefore it is necessary to match the reference image with the cylinder assignment.
The cylinder allocation standard is processed based on the keyway of the printing cylinder. Therefore, the key groove position of the cylinder drive unit is input to the inspection machine, and the cylinder allocation standard is recognized.
[0016]
【The invention's effect】
As described above, by adopting the defect detection method for printed matter of the present invention, it is not necessary to inspect the entire paper, so it is not necessary to eliminate defects other than the product that has occurred by inspecting the entire paper. , Improve efficiency and yield.
[Brief description of the drawings]
FIGS. 1A and 1B show an embodiment of a sheet-like printed material used in a defect detection method for printed materials according to the present invention, where FIG. 1A is a schematic explanatory view of a state before mask processing and FIG.
FIG. 2 is a schematic explanatory view showing a state in which a printed material is assigned to a cylinder.
FIG. 3 is a block diagram illustrating each component of gravure printing.
4 is a schematic explanatory diagram showing an outline of a print drying unit in FIG. 3; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Rolled-up printing paper 2 ... Paper feed part 3 ... Dancer roller part 4 ... Print drying part 5 ... Cutting part 6 ... Gravure cylinder 7 ... Impression cylinder 10 ... Sheet-like printed matter 11 ... Product 12 ··· Out of the range of the pattern that does not become a product 13 ··· Defects 14 ··· Mask processing (shaded area)

Claims (1)

Each frame of a continuous sheet-like printed matter obtained by continuously printing frames having a width (W) and a length (L) in the flow direction in which the same pattern is printed is represented by (W / m) × (L / n ) Are divided into m × n inspection areas, and the m × n inspection areas are selected and imaged one by one for each frame, and each inspection area image and a reference corresponding to the image are selected. When a pattern is compared with an image and a defect is judged from the result, a part outside the product is regarded as an out-of-inspection area, and the address outside the in-inspection area in the m × n division is evaluated, A defect detection method for a printed matter that detects defects occurring in the sheet-like printed matter by excluding the address of the print from the inspection object , wherein the cylinder allocation reference of the pattern is processed based on the keyway of the printing cylinder, and the printing cylinder is driven Depending on the keyway position of the unit Recognizing the cylinder allocation reference, matching the reference image with the cylinder allocation of the pattern, setting an out-of-picture mask area for excluding the address of the non-inspection area from the inspection object, and generated on the sheet-like printed matter A defect detection method for printed matter, characterized by detecting a defect.

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