JP2014177050A - Method of inspecting conditions of print plate and/or blanket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of detecting a defect causing print failure before printing on a printed matter and preventing generation of a damaged paper by inspecting conditions of a print plate and/or a blanket online shortly before printing on a printer.SOLUTION: A device detects a defect causing print failure and prevents generation of a damaged paper before printing on a printed matter 1 by inspecting conditions of a print plate 7 and/or blanket 10 online shortly before printing on a printer. The device suppresses generation of a print damaged paper by constantly comparing and collating, and determining previous and next image data of the print plate 7 and the blanket 10 without requiring a master image which is previously registered.

Description

  The present invention relates to a method for inspecting foreign matter and dirt on a printing plate or a blanket immediately before printing when printing a printed matter.

  The inspection of the printing state on the printing press employs various methods because it can detect a printing abnormality during printing and can immediately cope with it.

  As a method for inspecting a printed material and confirming the printing state, in the process of transporting the printed material on the printing machine, a method of photographing an image of the printed material to be inspected with an imaging device and comparing it with a master image registered in advance An imaging system that images the printing surface of an article that is continuously printed on a certain printing press is arranged, and an appropriate master image is created using image data of a plurality of articles imaged by the imaging system. There is a printed matter inspection apparatus that inspects the quality of printing by detecting a difference between image data of a printed article sequentially imaged by the imaging system (see, for example, Patent Document 1).

  As a quantitative measurement method for substances such as ink and fountain solution present on lithographic printing plates instead of printed matter, the amount of substances on the plate surface can be determined by measuring the absorbance while maintaining the operating state of the printing press. There is one that quantifies and manages the printing state (for example, see Patent Document 2).

  Also, it is an inspection device that inspects invisible technology using infrared reflection absorbing ink used in securities printing products on a printing press. Some external reflection absorption characteristics are inspected by taking a waveform or an image with a line sensor and a CCD line sensor and comparing them with a waveform and an image stored in advance as reference values (see Patent Document 4).

  As an image pickup means described in Patent Document 4, there is a technique in which a CCD line sensor camera is used to compare and inspect a captured image and a reference image (see Patent Document 5).

JP-A-11-232460 JP-A-1-202641 JP 2009-160816 A JP-A-10-337935 JP 2006-226857 A

  In general, in the method of inspecting a printed matter after printing, the printed matter is sampled and taken out from the printing press. The operator confirms the color and printing, and makes fine adjustments within the range of the regular paper. Although it is suitable for such operations, it is not suitable for cases where printing failure continues and paper is lost continuously, such as blanket stains or abnormalities. For this reason, it is required to detect an abnormality at the earliest possible stage when a defect that immediately results in waste paper occurs.

  As in Patent Document 1, the method for inspecting a printed material can inspect the printed material continuously and is effective for extracting a printing defect at an early stage. However, the cause of the printing defect is the blanket cylinder. Even if it is due to the part before printing, etc., it was discovered by inspecting the printed material after printing, so when it was discovered, a large number of defective products had already occurred and wasted loss It was also a factor that put out a lot of paper.

  According to Patent Document 2, the ink and dampening water supplied to the plate surface of the wet offset printing press during printing are quantitatively measured without stopping during machine operation, and the pattern on the plate surface is inspected. It can't be done.

  According to Patent Document 3, since the blanket is confirmed at the stage before printing, the amount of waste paper generated can be reduced compared with the inspection after printing when there is an abnormality in the blanket, which is the aim of the present invention. Therefore, it is necessary to register master data, and it is necessary to register each time a symbol is changed.

  According to Patent Document 4, in the printing process or inspection process of infrared ink used for securities printing, the printed matter conveyed after printing is inspected, and the printing plate on the printing press is not inspected.

  According to Patent Document 5, the purpose is to inspect the printed material as in Patent Document 4, and the plate surface cannot be inspected.

  Therefore, the present invention detects defects that cause printing defects before printing on a substrate by online inspection of the printing plate surface and / or blanket immediately before printing on a printing press. An object of the present invention is to provide an apparatus for preventing paper generation.

  The present invention can be applied to any type of printing machine as long as it is a printing machine having a printing plate surface and / or a blanket cylinder, and secures a place for attaching an illumination device and an imaging device to the printing plate surface and blanket immediately before printing. It is to provide an apparatus that can handle all of them if possible.

  The present invention does not require a master image to be registered in advance, and is characterized by always comparing and determining the image data of the preceding and subsequent printing plate surfaces or blankets, and can respond immediately to any design Is to provide.

  The present invention is a method for inspecting the state of a printing plate surface and / or blanket immediately before printing on-line during printing on a printing press, and illumination means for irradiating light on the printing plate surface and / or the surface of the blanket. Imaging means for photographing the printing plate surface and / or blanket illuminated by the illumination means, and an image photographed by the imaging means is taken as image data of the printing plate surface and / or blanket and binarized. A storage unit for storing, an image verification unit for comparing and comparing the image data stored in the storage unit and the image data of the next printing plate and / or blanket captured by the imaging unit, and the image verification unit A determination unit that determines whether the collated image data and the next image data match, and the determination unit The control means and the notification means performs notification of the print stop and inconsistency information when it is determined that no match has been a main structure.

  Since defects such as smudges and disappearance of image lines can be inspected before printing, it can be expected that printing waste paper can be prevented from occurring.

  The present invention can be applied to any type of printing machine as long as it is a printing machine having a printing plate surface or a blanket cylinder, and can be used as long as a place for attaching an illumination device and an imaging device to the printing plate surface or blanket immediately before printing can be secured. It is possible.

  When the present invention is used in a rotary printing press, the printing plate cylinder can be a single cylinder or any number of cylinders.

  Since the present invention is characterized by always comparing and judging image data of the front and back printing plates or blankets, a master image that needs to be registered in advance is not required, and any design can be dealt with immediately. It is.

  Since the present invention does not require a master image that needs to be registered in advance, it can be inspected without being influenced by machine differences or the like inherent in the printing machine.

It is a flowchart of a test | inspection when implementing this invention. The present invention is an embodiment in letterpress printing or flexographic printing. The present invention is an embodiment in an intaglio printing press. The present invention is an embodiment of a plate surface of an offset printing machine. The present invention is an embodiment in a blanket of an offset printing press. The present invention is an embodiment in a gravure printing machine. The present invention is an embodiment of a cylinder type screen printing machine.

  The form for implementing this invention is demonstrated below. However, the present invention is not limited to only the modes for carrying out the embodiments described below, and includes various other embodiments within the scope of the technical idea described in the claims.

  The present invention is a method for inspecting the state of a printing plate surface or a blanket immediately before printing on-line during printing on a printing press. The lighting device irradiates light on the surface of the printing plate surface or the blanket, and the illumination device illuminates the light. An image capturing device that captures the printed printing plate or blanket as image data, a storage device that stores the image data, image data stored in the storage device, and image data of the next printing plate surface or blanket captured by the imaging device. When it is determined by the determination means that the image collation device to be compared and the image data collated by the image collation device and the next image data match, and the determination means A control device and a notification device that notify printing stop and mismatch information are mainly configured.

  Since the present invention is characterized by always comparing and judging image data of the front and back printing plates or blankets, a master image that needs to be registered in advance is not required, and any design can be dealt with immediately. It has a simple structure.

  The object of the present invention is to inspect foreign matter and dirt, and therefore, it is sufficient that the image data can be binarized, so a color sensor is not required.

  The imaging device of the present invention is not particularly limited as long as it can capture an image. Of course, it is natural to discriminate by the color of visible light, but when performing inspections such as infrared reflection, infrared absorption, infrared transmission, and fluorescence emission according to the characteristics of the printing ink, an appropriate image is obtained. A known imaging device that can be used may be used. In that case, the light emitted from the lighting apparatus may be infrared light, or ultraviolet light may be used for fluorescent light emission, or a light source may be appropriately selected.

  The present invention irradiates light on a printing plate surface and / or blanket surface on a printing press with a lighting device, photographs the printing plate surface and / or blanket illuminated thereby with a camera, and takes the image as image data. Remember. Similarly, the printing plate surface and / or blanket at the next position taken is photographed and stored, and compared with the image data of the printing plate surface and / or blanket taken immediately before. This comparison method may be a known method such as pattern matching.

  After that, the adjacent printing plate or blanket is photographed, and then the storage and comparison of the image data are always repeated. If it is determined that the two image data do not match, there is foreign matter or dirt on the printing plate or blanket. This is a mechanism for automatically stopping printing.

  When comparing two pieces of image data, it is determined that there is a difference between the pieces of image data and the cause of the mismatch is foreign matter or dirt. About the magnitude | size of the difference, the mechanism (not shown) which memorize | stores the criterion about a foreign material or a stain | pollution | contamination beforehand is provided, and it shall be able to adjust suitably.

  Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 2 is a schematic diagram showing an embodiment of a relief printing press or a flexographic printing press having a similar mechanism. The plate surface 7 inked from the inking roller 6 is printed by passing the substrate 1 between the impression cylinder 8 and rotating.

  At this time, the surface of the plate cylinder (plate surface) 7 is picked up by the imaging device 2 immediately after the rotating plate cylinder (plate surface) 7 is inked by the inking roller 6 and immediately before printing on the substrate 1. Shoot. First, a plate cylinder (plate surface) 7 is first photographed, stored, and used as a reference image A. Immediately after that, an inspection image B which is a portion corresponding to the next symbol following the symbol imaged immediately before is photographed.

  The reference image A and the inspection image B are inspected by well-known pattern matching by changing the contrast so that machine determination is easy by binarization. Accordingly, it is determined whether there is a difference from the ink adhesion states of the two image data of the reference image A and the inspection image B, and if it is determined that there is a difference, it is determined that the object is foreign matter or dirt.

  At this time, when it is determined that there is foreign matter or dirt on the printing plate surface, the printing is automatically stopped. The details of the mechanism of the automatic stop mechanism differ depending on the machine specifications of the relief printing press or flexographic printing machine. In general, the automatic stop mechanism is notified by an alarm device and stopped by sending a print stop signal. It can be executed with.

  Subsequently, the inspection image B is stored as the reference image B, and the portion corresponding to the pattern of the plate cylinder (plate surface) 7 immediately after is stored as the inspection image C. Similarly, the reference image B and the inspection image C are inspected by pattern matching by changing the contrast so that machine determination is easy by binarization. Inspection is performed by repeating this process.

  Embodiment 2 of the present invention will be described in detail with reference to the drawings. FIG. 3 is a schematic diagram showing an embodiment of an intaglio printing press. The plate surface 7 to which ink has been applied from the inking roller 6 is in a state in which excess ink is removed by the wiping roller 9 so that printing can be performed on the printing material 1. Printed by rotating.

  At this time, the surface of the plate cylinder (plate surface) 7 is rotated by the imaging device 2 immediately after the rotating plate cylinder (plate surface) 7 removes excess ink by the wiping roller 9 and immediately before printing on the substrate 1. Shoot. First, a plate cylinder (plate surface) 7 is first photographed, stored, and used as a reference image A1. Immediately after that, an inspection image B1 that is a portion corresponding to the next symbol following the symbol imaged immediately before is imaged.

  The reference image A1 and the inspection image B1 are inspected by well-known pattern matching by changing the contrast so that machine determination is easy by binarization. Accordingly, it is determined whether there is a difference from the ink adhesion states of the two image data of the reference image A1 and the inspection image B1, and if it is determined that there is a difference, it is determined that the object is foreign matter or dirt.

  At this time, when it is determined that there is foreign matter or dirt on the printing plate surface, the printing is automatically stopped. The details of the mechanism of the automatic stop mechanism are different depending on the machine specifications of the intaglio printing press. In general, the automatic stop mechanism can be executed by notifying by an alarm device and stopping by sending a print stop signal.

  Subsequently, the inspection image B1 is stored as the reference image B1, and the portion corresponding to the pattern of the plate cylinder (plate surface) 7 immediately after is stored as the inspection image C1. Similarly, the reference image B1 and the inspection image C1 are inspected by pattern matching by changing the contrast so that machine determination is easy by binarization. Inspection is performed by repeating this process.

  Embodiment 3 of the present invention will be described in detail with reference to the drawings. FIG. 4 is a schematic view showing an embodiment of the plate cylinder (plate surface) 7 of the offset printing machine. The plate surface 7 to which ink has been applied from the inking roller 6 is printed by transferring the ink to the blanket cylinder 10 and passing the substrate 1 between the impression cylinder 8 and rotating it.

  At this time, the surface of the plate cylinder (plate surface) 7 is picked up by the imaging device 2 immediately after the rotating plate cylinder (plate surface) 7 applies ink from the inking roller 6 to immediately before transfer to the blanket cylinder 10. Shoot. First, a plate cylinder (plate surface) 7 is first photographed, stored, and used as a reference image A2. Immediately after that, an inspection image B2 that is a portion corresponding to the next symbol following the symbol imaged immediately before is imaged.

  The reference image A2 and the inspection image B2 are inspected by well-known pattern matching by changing the contrast so that machine determination is easy by binarization. Accordingly, it is determined whether there is a difference from the ink adhesion states of the two image data of the reference image A2 and the inspection image B2, and if it is determined that there is a difference, it is determined that the object is foreign matter or dirt.

  At this time, when it is determined that there is foreign matter or dirt on the printing plate surface, the printing is automatically stopped. The details of the mechanism of the automatic stop mechanism differ depending on the machine specifications of the offset printing machine, but in general, it can be executed by notifying by an alarm device and stopping by sending a print stop signal.

  Subsequently, the inspection image B2 is stored as the reference image B2, and the portion corresponding to the pattern of the plate cylinder (plate surface) 7 immediately after is stored as the inspection image C2. Similarly, the reference image B2 and the inspection image C2 are inspected by pattern matching by changing the contrast so that machine determination is easy by binarization. Inspection is performed by repeating this process.

  Embodiment 4 of the present invention will be described in detail with reference to the drawings. FIG. 4 is a schematic diagram showing an embodiment of the blanket cylinder 10 of the offset printing press. The plate surface 7 to which ink has been applied from the inking roller 6 is printed by transferring ink to the blanket cylinder 10 while rotating, passing the substrate 1 between the impression cylinder 8 and rotating.

  At this time, immediately after the rotating plate cylinder (plate surface) 7 transfers the ink to the blanket cylinder 10 and immediately before the blanket cylinder 10 rotates and prints on the substrate 1, the imaging apparatus 2 performs the blanket cylinder. 10 surfaces are photographed. First, the blanket cylinder 10 is first photographed, stored, and used as a reference image A3. Immediately after that, an inspection image B3 that is a portion corresponding to the next symbol following the symbol imaged immediately before is imaged.

  The reference image A3 and the inspection image B3 are inspected by well-known pattern matching by changing the contrast so that machine determination is easy by binarization. Thus, it is determined whether there is a difference from the ink adhesion states of the two image data of the reference image A3 and the inspection image B3, and if it is determined that there is a difference, it is determined that the object is foreign matter or dirt.

  At this time, when it is determined that there is foreign matter or dirt on the printing plate surface, the printing is automatically stopped. The details of the mechanism of the automatic stop mechanism differ depending on the machine specifications of the offset printing machine, but in general, it can be executed by notifying by an alarm device and stopping by sending a print stop signal.

  Subsequently, the inspection image B3 is stored as the reference image B3, and the portion corresponding to the pattern of the plate cylinder (plate surface) 7 immediately after is stored as the inspection image C3. Similarly, the reference image B3 and the inspection image C3 are inspected by pattern matching by changing the contrast so that machine determination is easy by binarization. Inspection is performed by repeating this process.

  Embodiment 5 of the present invention will be described in detail with reference to the drawings. FIG. 6 is a schematic diagram showing an embodiment in a gravure printing machine. The plate surface 7 to which ink has been applied from the inking roller 6 is scraped off by the doctor 4 and is rotated in a state where the ink is accumulated in the cells of the plate cylinder (plate surface) 7. The plate cylinder (plate surface) 7 is printed by passing the substrate 1 between the plate cylinder 8 and the impression cylinder 8 and rotating.

  At this time, after the rotating plate cylinder (plate surface) 7 is inked by the inking roller 6, immediately after the excess ink is scraped off by the doctor 4, until immediately before printing on the substrate 1, The surface of the plate cylinder (plate surface) 7 is imaged by the imaging device 2. First, a plate cylinder (plate surface) 7 is first photographed, stored, and used as a reference image A4. Immediately after that, an inspection image B4 that is a portion corresponding to the next symbol following the symbol imaged immediately before is imaged.

  The reference image A4 and the inspection image B4 are inspected by well-known pattern matching by changing the contrast so that machine determination is easy by binarization. Accordingly, it is determined whether there is a difference from the ink adhesion states of the two image data of the reference image A4 and the inspection image B4, and if it is determined that there is a difference, it is determined that the object is foreign matter or dirt.

  At this time, when it is determined that there is foreign matter or dirt on the printing plate surface, the printing is automatically stopped. The details of the mechanism of the automatic stop mechanism are different depending on the machine specifications of the gravure printing machine, but in general, the automatic stop mechanism can be executed by notifying by an alarm device and stopping by sending a print stop signal.

  Subsequently, the inspection image B4 is stored as the reference image B4, and the portion corresponding to the pattern of the plate cylinder (plate surface) 7 immediately after is stored as the inspection image C4. Similarly, the reference image B4 and the inspection image C4 are inspected by pattern matching by changing the contrast so that machine determination is easy by binarization. Inspection is performed by repeating this process.

  Embodiment 6 of the present invention will be described in detail with reference to the drawings. FIG. 7 is a schematic view showing an embodiment of a cylinder type screen printing machine. The cylinder type screen printing machine supplies an appropriate amount of ink to the inside of the plate cylinder (plate surface) 7 by an ink supply device 13 installed inside the plate cylinder (plate surface) 7. The plate cylinder (plate surface) 7 passes the substrate 1 between the plate cylinder 8 and the squeegee 12 inside the rotating plate cylinder (plate surface) 7 presses the ink, so that the plate cylinder (plate surface) 7 screen mesh. Ink is extruded to the outside and printed on the substrate 1 at the contact point with the impression cylinder 8.

  At this time, the surface of the rotating plate cylinder (plate surface) 7 is imaged by the imaging device 2. First, a plate cylinder (plate surface) 7 is first photographed, stored, and used as a reference image A5. Immediately after that, an inspection image B5 that is a portion corresponding to the next symbol following the symbol imaged immediately before is imaged.

  The reference image A5 and the inspection image B5 are inspected by well-known pattern matching by changing the contrast so that machine determination is easy by binarization. Thus, it is determined whether there is a difference from the ink adhesion states of the two image data of the reference image A5 and the inspection image B5. If it is determined that there is a difference, it is determined that the object is foreign matter or dirt.

  At this time, when it is determined that there is foreign matter or dirt on the printing plate surface, the printing is automatically stopped. The details of the mechanism of the automatic stop mechanism differ depending on the machine specifications of the cylinder type screen printing machine or flexographic printing machine. In general, it is notified by an alarm device and stopped by sending a print stop signal. Can be executed.

  Subsequently, the inspection image B5 is stored as the reference image B5, and the portion corresponding to the pattern of the plate cylinder (plate surface) 7 immediately after is stored as the inspection image C5. Similarly, the reference image B5 and the inspection image C5 are inspected by pattern matching by changing the contrast so that machine determination is easy by binarization. Inspection is performed by repeating this process.

DESCRIPTION OF SYMBOLS 1 Printed object 2 Imaging device 3 Illumination device 4 Doctor 5 Duct roller 6 Inking roller 7 Plate cylinder (plate surface)
8 Pressure cylinder 9 Wiping roller 10 Blanket cylinder 11 Water source roller 12 Squeegee 13 Ink supply device

Claims (1)

A method for inspecting the state of a printing plate and / or blanket immediately before printing on-line during printing on a printing press,
Illuminating means for irradiating light to the printing plate surface and / or the surface of the blanket;
Imaging means for photographing the printing plate surface and / or blanket illuminated by the illumination means;
Storage means for storing an image photographed by the imaging means as image data of the printing plate surface and / or blanket, binarized, and stored;
Image collating means for comparing and collating the image data stored in the storage means with the image data of the next printing plate and / or blanket captured by the imaging means;
Determination means for determining whether or not the image data collated by the image collating means matches the next image data;
Control means for notifying the printing stop and mismatch information when it is determined by the determination means that they do not match;
A method for inspecting the state of a printing plate surface and / or blanket, comprising:

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