JP2009250612A - Print pattern inspection device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a print pattern inspection method and an inspection device capable of suppressing pseudo defect detection by reducing an influence of meandering or expansion/contraction of a base material to be printed, and detecting a defect growing little by little. <P>SOLUTION: This print pattern inspection device is equipped with an imaging means for imaging a print pattern, and outputting inspection object image data; a tension monitoring means for monitoring tension of the base material to be printed used as an imaging object by an imaging means; the first storage means for storing the inspection object image data acquired by the imaging means; the second storage means for storing master image data used as a reference for inspection; a quality determination means for determining the quality of the inspection object image data by comparing the inspection object image data with the master image data; and a master image data updating means for allowing the second storage means to store the newest inspection object image data stored in the first storage means as the master image data, when the tension of the base material to be printed which is monitored by the tension monitoring means is out of a range of a prescribed value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for printed picture inspection using a material obtained by winding a long substrate to be printed in a roll shape.

  In a printing process in which a roll of a long substrate to be printed is used as a raw material, printed pattern inspection is performed by inspecting defective print areas by comparing image data of a master image serving as a reference and an inspection image to be inspected. It is done.

  For the master image that serves as a reference, the digital plate-making data itself or image data obtained by picking up a printed material that has been determined to be non-defective by visual confirmation or the like is used. There are cases where it is updated one after another, such as a master image to be inspected. (See Patent Documents 1 and 2)

  However, the above conventional method has the following problems. First, it is a case where predetermined image data is fixedly used as a reference master image. However, if the substrate to be printed is a long object, phenomena such as meandering and expansion / contraction tend to occur. Will also be detected.

  Next, there is a case where the image data of the immediately previous inspection object is updated as a master image of the immediately subsequent inspection object, and the detection ability is good for detecting defects that grow little by little. There is a problem that it is low and misses defects.

JP 2007-033247 A JP-A-7-101048

  The present invention solves the above-described problems, an inspection method capable of reducing the influence of the meandering and expansion / contraction of the base material to suppress the detection of pseudo defects, and capable of detecting defects that grow little by little. An object is to provide an inspection device.

In order to achieve the above object, according to a first aspect of the present invention, there is provided an apparatus for inspecting a printed pattern in a printing machine that performs printing while winding and transporting a long printed substrate continuously. There,
An imaging unit that is installed in a predetermined region of the conveyance path of the substrate to be printed, images the printed pattern, and outputs inspection target image data;
Tension monitoring means for monitoring the tension of the substrate to be printed in a predetermined area of the conveyance path that is the imaging target of the imaging means;
First storage means for storing inspection object image data obtained by the imaging means;
Second storage means for storing master image data serving as an inspection reference;
A pass / fail judgment means for comparing the test object image data with the master image data to judge pass / fail of the test object image data;
When the tension of the substrate to be printed monitored by the tension monitoring unit is out of a predetermined value range, the latest inspection target image data stored in the first storage unit is used as master image data as the second image data. Master image data update means to be stored in the storage means;
A printed pattern inspection apparatus characterized by comprising:

Further, in claim 2 of the present invention, there is a method for inspecting a printed pattern in a printing machine that performs printing while winding and transporting a long substrate to be printed continuously,
An imaging stage for imaging the printed pattern and outputting inspection target image data in a predetermined region of the conveyance path of the substrate to be printed;
A tension monitoring step of monitoring the tension of the substrate to be printed in a predetermined region of the transport path that is the imaging target in the imaging step;
A first storage stage for storing inspection object image data obtained in the imaging stage;
A second storage stage for storing master image data as a reference for inspection;
A pass / fail judgment stage for comparing the test object image data with the master image data and judging pass / fail of the test object image data;
A master image that updates the latest inspection object image data stored in the first storage step as master image data when the tension of the printing substrate monitored in the tension monitoring step is out of a predetermined value range. A data update phase;
A printed pattern inspection method characterized by comprising:

  In the present invention, the correction of the meandering and expansion / contraction is not performed by image processing, but the master image serving as a reference is updated so that the influence of the meandering and expansion / contraction of the substrate to be printed is suppressed at the stage of capturing the image. It is possible to do it at an appropriate timing.

  In other words, the cause of the meandering and expansion / contraction of the substrate to be printed is largely due to the variation in the tension applied to the substrate to be printed, so that there is a predetermined variation in the tension at the location to be imaged on the substrate to be printed. In this case, the master image serving as a reference is updated.

  The present invention has the following three remarkable effects.

  [1] In the printed pattern inspection of a long printed substrate, it is possible to automatically determine and update the update timing of the master image. It is possible to identify defects.

  [2] Since the master image is updated as appropriate, it is possible to reduce both false defects, which has been difficult until now, and detect defects that grow little by little.

  [3] By monitoring the tension of the substrate to be printed, the production behavior can be managed by using the correlation between the tension and the judgment of the pattern inspection and using the meandering sensor together.

  Hereinafter, although an embodiment of the present invention is described using a drawing, the present invention is not limited to this embodiment. FIG. 1 shows a schematic configuration of a printing pattern inspection apparatus according to an embodiment of the present invention installed in the vicinity of a winding unit of a printing machine.

  A long substrate to be printed is conveyed from the right side of FIG. 1, printed by each printing unit, and wound up in a roll shape by a winding unit 22 through an outfeed unit 21.

  A camera 11 that is an imaging unit of the printed pattern inspection apparatus according to the present embodiment is installed in the outfeed unit 11 to set a predetermined area as an imaging area, and a printing surface of a substrate to be printed passing therethrough has a predetermined timing. And is sent to the inspection apparatus 13 as an inspection target image.

  It is assumed that the imaging region of the camera 11 is illuminated with illumination light by an illuminating unit as necessary, and has a brightness that allows acquisition of an appropriate inspection image. Further, the imaging of the camera 11 is performed at a timing according to the cycle length of printing performed by each printing unit. That is, imaging is performed at a timing such that a fraction of the cycle length of a printed pattern or a portion of several cycles can be captured as one image.

  The inspection target image picked up by the camera 11 is sent to the inspection device 13 and compared with a master image stored in advance in a storage unit constituting the inspection device 13 to determine whether it is acceptable. Data generated by the inspection device 13 includes inspection result data indicating that there is a printing defect at a distance of m from the unwinding end of the substrate to be printed at a location where the printed pattern is defective on the substrate to be printed. It is written in the file and stored in the storage means.

  Or you may make it a predetermined | prescribed mark enter into the location where there was a printed pattern defect on a to-be-printed base material.

  Here, the reason why the camera 11 is installed in the outfeed unit 21 will be described. First, the main cause of the meandering and expansion / contraction of the substrate is largely due to the tension fluctuation applied to the substrate to be printed. In the printing press, the magnitude of the tension that acts on the substrate to be printed varies depending on each part, and there is also a part where tension control is performed over time.

  Therefore, it is desirable to install the imaging means of the inspection apparatus at a site where the change in tension with time does not occur, that is, a site where the tension is constant throughout production. However, when the imaging unit is unavoidably installed at a site where the temporal tension control is performed due to the installation space of the imaging unit, it is necessary to inspect the printed pattern in consideration of the influence of the tension variation.

  Here, since the part called the outfeed part of the printing press is a part where the tension applied to the substrate to be printed during production is constant, the inspection apparatus according to the present embodiment installs the camera 11 serving as an imaging unit. .

  In addition, a tension monitoring monitor 12 that measures the tension of the substrate to be printed in the outfeed unit 21 during production and outputs the measured value is installed at any location on the outfeed unit 21, and the inspection apparatus 13 side Try to get a measurement of that tension. In general, the printing machine often has a function of constantly measuring the tension of the outfeed unit 21, and therefore, the inspection device 13 stores the measured value data of the tension of the outfeed unit 21 on the printing press side. You may make it acquire always.

  The inspection device 13 compares the acquired tension measurement value of the outfeed unit 21 with a preset management range, and prepares to update a master image as a reference when the management range is exceeded.

  Further, when the state where the tension measurement value exceeds the predetermined management range occurs continuously for a predetermined time or longer, a master image update timing signal is output inside the inspection apparatus 13. When this master image update timing signal is generated, the storage means constituting the inspection apparatus 13 erases the previous master image and determines the latest one of the currently stored inspection target images (however, it is determined that there is no defective portion). Is stored as a new master image and used for comparison with subsequent images to be inspected.

  The inspection device 13 repeats the above-described process every time there is a change in the tension measurement value data.

  Since the new master image is an image after the tension value fluctuates, it is in a state in which the subsequent inspection target image is similar in the size and tendency of expansion / contraction and meandering of the substrate to be printed. Therefore, it is possible to suppress the occurrence of pseudo defects due to expansion and contraction.

In addition, since the master image serving as a reference is updated only when there is a predetermined change in the tension of the substrate to be printed, it is possible to detect defects that grow little by little.

It is a schematic diagram which shows schematic structure of the printed pattern inspection apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Camera 12 ... Tension monitoring monitor 13 ... Inspection apparatus 21 ... Outfeed part 22 of printing press ... Winding part of printing press

Claims (2)

An apparatus for inspecting a printed pattern in a printing machine that performs printing while continuously unwinding and transporting a long substrate to be printed,
An imaging unit that is installed in a predetermined region of the conveyance path of the substrate to be printed, images the printed pattern, and outputs inspection target image data;
Tension monitoring means for monitoring the tension of the substrate to be printed in a predetermined area of the conveyance path that is the imaging target of the imaging means;
First storage means for storing inspection object image data obtained by the imaging means;
Second storage means for storing master image data serving as an inspection reference;
A pass / fail judgment means for comparing the test object image data with the master image data to judge pass / fail of the test object image data;
When the tension of the substrate to be printed monitored by the tension monitoring unit is out of a predetermined value range, the latest inspection target image data stored in the first storage unit is used as master image data as the second image data. Master image data update means to be stored in the storage means;
A printed pattern inspection apparatus comprising:
A method of inspecting a printed pattern in a printing machine that performs printing while continuously unwinding and conveying a long substrate to be printed,
An imaging stage for imaging the printed pattern and outputting inspection target image data in a predetermined region of the conveyance path of the substrate to be printed;
A tension monitoring step of monitoring the tension of the substrate to be printed in a predetermined region of the conveyance path that is the imaging target in the imaging step;
A first storage stage for storing inspection object image data obtained in the imaging stage;
A second storage stage for storing master image data as a reference for inspection;
A pass / fail judgment stage for comparing the inspection target image data with the master image data to determine pass / fail of the test target image data;
A master image that updates the latest inspection object image data stored in the first storage step as master image data when the tension of the printing substrate monitored in the tension monitoring step is out of a predetermined value range. A data update phase;
A printed pattern inspection method comprising: