JP2009160816A - Aboard-the-printer checking method of printing plate or blanket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which enables instantaneous detecting of the total defects of all pieces of printed matter aboard the printer and also, photographing of a stable image, with the priority of photographed image stability, through checking the state of a printing plate right before printing and thereby, detecting the defects of the printing plate before transferring a printing pattern to an object to be printed. <P>SOLUTION: This method is employed to check online the state of the printing plate and/or the blanket right before printing, while the printing process is under way. In addition, this method comprises an illuminating means which emits light to the surface of the printing plate and/or the blanket, an image entry means which enters the printing plate and/or the blanket to which light is emitted by the illuminating means, as image data, a storage means which stores image data, an image collating means which comparatively collates the image data with the previously registered reference image data of the printing plate or the blanket, a decision means which decides whether or not the image data collated by the image collating means and the reference image data coincide with each other, and a control means which annunciates information on printing stoppage and/or non-coincidence, when it is decided by the decision means that the non-coincidence (negative) has been established. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for inspecting a printing plate and / or a blanket immediately before printing when printing a printed material.

  As a quantitative measurement method for substances such as ink and fountain solution present on the plate surface of lithographic printing (wet offset), the amount of material 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. (See Patent Document 1)

  In addition, as a quantitative measurement method for substances such as ink and fountain solution present on the lithographic printing plate, material measurement at any plate surface position is performed, and information on any plate surface position stored in advance (calibration). Line) and the measured absorbance, there is a measuring device for obtaining the amount of the substance to be measured. (See Patent Document 2)

  Also, in lithographic printing, an apparatus for detecting coloring in an ink band on a printing plate during operation detects an abnormality on the printing plate by inspecting the ink band. (See Patent Document 3)

  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 capturing unit described in Patent Document 4, there is a device that uses a CCD line sensor camera and performs a comparative inspection between a captured image and a reference image. (See Patent Document 5)

  Furthermore, in a printing machine to which ink having invisible characteristics is supplied, there is an ink supply monitoring apparatus that continuously inspects the characteristics of the supplied ink in order to detect an ink supply error. (See Patent Document 6)

JP-A-1-202641 Japanese Examined Patent Publication No. 6-51404 JP 2002-192698 A JP-A-10-337935 JP 2006-226857 A JP 2007-136986 A

  According to Patent Literature 1, 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. I can't do it.

  According to Patent Document 2, although it is an apparatus capable of measuring ink, fountain solution, plate surface temperature, and the like at an arbitrary site with respect to the contents described in Patent Document 1, the design on the plate surface cannot be inspected.

  According to Patent Document 3, the color state of the ink band laid out on the printing plate is detected to detect or control the printing color state of the printed matter, and the design on the printing plate cannot be inspected.

  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.

  Inspecting printed matter as in Patent Literature 4 and Patent Literature 5 means that the medium (paper, film, etc.) of the material to be printed is affected by temperature and humidity, and the size of the pattern depends on the transfer pressure (printing pressure) during printing. There are fluctuating elements, and in order to capture the printed matter being transported, each sheet of paper generates a flutter due to static electricity, air resistance, and gravity, and to suppress the flutter in order to obtain a clear image It was necessary to blow air and install brushes.

  According to Patent Document 6, when printing using infrared transmission / reflection / absorption ink that is difficult to distinguish with similar colors in the visible light region, when an operator mistakes the ink and supplies ink to the printing machine, an alarm or the like is issued. This is for the purpose of public knowledge and does not inspect the printing plate.

  In this way, the ink characteristics (color, infrared reflection, infrared absorption, infrared transmission, magnetic value, fluorescence emission state, etc.) are inspected on a machine using a printing machine or inspection device or offline. This is already known from the respective patent documents. In addition, a method for inspecting a printed matter is popular for inspecting a printed pattern, and is also a known technique. However, when a printed matter is inspected, the printed matter is already in a state of being printed, and when a defect in the printed design is detected by an inspection device or the like, the same defective printed matter is generated.

Therefore, in the present invention, all the defects of the printed material are instantaneously detected on the printing machine, and the printed pattern is transferred to the printing material by inspecting the state of the plate immediately before printing as the stabilization of the captured image. It is possible to detect a defect before, and to provide a stable image.

The present invention is a method for inspecting the state of a printing plate surface and / or blanket immediately before printing online during printing,
Illuminating means for irradiating light to the printing plate surface and / or the surface of the blanket;
Image input means for inputting the printing plate surface and / or the blanket irradiated with light by the illumination means as image data;
Storage means for storing the image data;
Image collating means for comparing and collating the image data with reference image data of a printing plate or blanket registered in advance;
Determination means for determining whether or not the image data collated by the image collating means matches the reference image data;
Control means for notifying printing stop and / or inconsistency information when it is determined by the determination means that they do not match (no);
A printing plate and / or blanket inspection method on a printing press.

The light irradiated by the illuminating means is any one of visible light, UV light, and infrared light, and is a method for inspecting a printing plate and / or blanket on a printing press.

Further, the image input means is a printing plate and / or blanket on-press inspection method using at least one image input device among a CCD area camera, a CCD line camera, a color sensor, and a laser displacement sensor. is there.

Further, the image input means picks up an image of a wavelength region of the light having a wavelength of 700 nm or more, and is an inspection method on a printing plate and / or blanket on a printing press.

Further, the image collating means performs comparison collation by pattern matching between the image data and the reference image data by an arbitrary allowable value, or performs arbitrary binarization processing on the image data and the reference image data, and performs the binary processing. A method for inspecting a printing plate and / or a blanket on a printing press, characterized in that at least one comparison / collation is performed among comparison / collation to determine whether or not the number of pixels after the digitizing process falls outside a predetermined allowable value. .

Further, in the determination means, as a determination standard for discrepancy between the image data and the reference image data, in the case of a printing plate surface, plate scratches, plate surface contamination, ink adhesion to a non-printed portion of the plate surface, wiping to the plate surface If at least one of liquid rise, color difference of printing section, reprinting, plate cracking is against the standard,
In the case of a blanket, if at least one of the scratches on the blanket, dirt on the blanket, ink adhesion to the non-printed part of the blanket, color difference in the printed part, reprinting, and blanket breakage is against the standard,
Is a printing plate and / or blanket on-press inspection method.

Further, in the control means, at least one of image information, audio information, and character information is used to notify the inconsistency information.

According to the present invention, when a defect such as a stain on the plate surface or the blanket is generated by inspecting the printing plate or blanket on the printing press immediately before printing, the defect is detected immediately before the printing pattern is transferred to the printing material. By being able to detect, it becomes possible to detect earlier than inspecting the printed matter, and unnecessary waste paper is eliminated.
In addition, since the inspection object is not a medium such as paper or film by inspecting the printing plate or blanket, it is possible to suppress fluttering during conveyance, so it is possible to obtain a very clear extracted image and detect defects. The accuracy is also greatly improved.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings. However, the present invention is not limited to the best mode for carrying out the invention described below, and includes various other embodiments within the scope of the technical idea described in the scope of claims.

  The printing apparatus according to the present invention can be applied to all printing machines such as a rotary press and a flat bed machine, and can be applied to all cases as long as a place for attaching an imaging means to a printing plate or a blanket immediately before printing can be secured.

  The wavelength range selected by the illuminating means according to the present invention varies depending on the ink to be printed. For example, in the case of inspecting stains, defects, color tone, etc. of the printing plate and blanket, it is possible to inspect the image captured by using the visible light region (about 300 nm to less than 700 nm) as in the case of human eyes.

  FIG. 1 shows an image of the printing plate and blanket in the visible light region. In a, a normal image is observed, but in b, a thread-like foreign matter is mixed in, c is a state where scratches are generated on the plate surface and blanket, d is a state of solvent stain and liquid overflow in intaglio printing, or gravure A state in which the smear occurs at the doctor due to printing, e indicates a state in which the reproducibility of a part of the printing plate and the blanket is poor, and f indicates a state in which the part is reprinted.

  In the present invention, it is possible to inspect the abnormality of the printing plate and the blanket that occurs from b to f.

  In addition, when the infrared light region (700 nm or more) is used for the illumination means, on the printing plate and blanket using special ink used for securities, the image that can be observed in the visible light region is the image in the infrared light region. This is effective for inspecting anti-counterfeit printed matter in which the ink disappears. This is because the image that is to be developed in the infrared light region is mixed with a component that absorbs infrared light (carbon black pigment, etc.) in the ink and applied to the printing plate and blanket (hereinafter referred to as fleshing). When an image that is to be extinguished in a region is inlaid with a component that reflects or transmits infrared light, it can be observed in a similar color in human appearance, but in the infrared light region, some or all of the image changes It is possible to perform the same inspection as when observing the state under the infrared light region.

FIG. 2 shows the state of a printing plate and a blanket using ink using infrared reflection / absorption characteristics. In a, it is a state (visible) in a visible light range, b shows an infrared absorption part. c shows an infrared transmission part. By combining the infrared transmission and absorption, an image a appears in the visible light region, and an image like d appears in the infrared light region.
In the present invention, it is possible to determine whether or not there is an abnormality in the image d. Since e and f partially exhibit infrared absorption, both are determined as “No”.

  Furthermore, when the ultraviolet light region (300 nm or less) is used for the illumination means, the plate surface and the blanket that are only colored in the visible light region in the plate surface and the blanket that use special ink used for securities, In the ultraviolet light region, it is effective for inspecting a printing plate and a blanket using ink that is excited and emits light under the influence of ultraviolet light. This is because when an image that wants to emit light in the ultraviolet light region is printed with a material that absorbs and excites ultraviolet light (fluorescent pigment, etc.) in the ink, it can be observed in color expression in the human eye. Then, it is possible to perform the same inspection as observing a plate surface and a blanket in which a part or all of an image emits light under an ultraviolet light region.

  FIG. 3 shows the state of the plate surface and blanket using the ultraviolet light emitting ink. a is a state in a visible light region, and b shows a state of ultraviolet light emission. c is a state in which ultraviolet light emission is weak, and in the present invention, it is possible to determine whether or not an abnormality such as c is possible.

  As a matter of course, in inspection of securities using infrared transmission / absorption ink and ultraviolet light emission ink, it is possible to detect defects such as b to f in FIG. 1 under each condition.

  The image input means of the present invention is not particularly limited as long as it can be captured as an image. A CCD area camera sensor and a CCD line camera sensor are preferable when it is desired to inspect as an image, and a CCD line camera sensor is preferable for obtaining a more accurate image.

  In addition, in the case of inspecting whether ink is adhered to a predetermined portion of a certain printing plate and blanket, for example, as a numerical data instead of as an image, a color sensor (for example, CZ-H32 manufactured by Keyence Corporation) is used. It is also possible to obtain numerical data and collate the data with the collating means.

In addition, in the case of printing plates and blankets using ink that has the characteristic that an image appears or disappears in the infrared light region, a specific part appears or disappears in the infrared light region by selecting the laser wavelength of the laser displacement sensor. It is also possible to inspect whether to do. This makes it possible to discriminate between ink having infrared reflection and transmission and ink having infrared absorption characteristics when the laser beam range of the laser displacement sensor (eg, Keyence Corporation: PS-45) is around 700 nm. Yes. Therefore, it is possible to collect the state of the plate surface and the blanket having infrared reflection / infrared absorption characteristics as data without installing infrared illumination with a CCD camera or the like and imaging through a filter near 700 nm.
Even in this case, the laser displacement sensor apparently includes the light projecting unit and the light receiving unit. Strictly speaking, since the light projecting unit and the light receiving unit are separately provided, the illumination means in the present invention is the light projecting unit. Thus, the imaging means can be replaced with a light receiving unit.

  Naturally, by selecting and using the wavelength range of other laser displacement sensors, ink that emits light in the ultraviolet region as well as ink with infrared reflection / infrared absorption characteristics is collected as numerical data. Is possible.

The storage means in the present invention may be any image data as long as it can be stored as an image, and various formats such as JPEG, TIFF, BMP, and GIF formats can be used. A format capable of data processing is preferable.
It is also possible to store not only images but also numerical values different from image data, such as the number of pixels after image processing such as binary value, and numerical values obtained by a laser displacement sensor or a color sensor. .

  The collating means is not particularly limited as long as it can collate and compare image data stored in advance and newly acquired image data. Preferably pattern matching between pre-stored image data and captured image data, and, if data is obtained numerically, a method of comparing previously stored numerical values with newly obtained numerical values There is.

  Further, there is a method of comparing and collating with the previous image data instead of the image data stored in advance, but any method of collating with any stored image data may be used.

The determination unit determines whether the data collated by the collation unit is acceptable. The determination means according to the present invention is capable of outputting a determination result of “No” when the threshold value is below a certain arbitrary threshold value. Naturally, an output when the determination result is “possible” is also possible.
In addition, the determination means can select whether the threshold value stored in advance according to the required inspection standard should be fixed or whether the threshold value has a range (blurring) according to the collation result. When the threshold value is fixed, it is preferable to fix it on the basis that the abnormality of the printing plate and the blanket cannot be satisfied as a product, and the threshold value range depending on the collation result is the range that generally satisfies the product standard. It is used when the numerical value may vary, but preferably the criterion is fixed, and if there is a possibility that the image data and numerical data may vary due to some disturbance etc. A method of giving it may be used.

FIG. 4 shows the state of the threshold in the present invention.
a is a state in which the threshold is fixed, and if it is an image other than a, a determination of “No” is made. b is a threshold value having a range, and if it is in the range of b, it is judged “Yes”, and if it is outside the range, it is judged “No”.

In the control means, there are a method of notifying the operator by an alarm or the like based on the output result determined as “NO” by the determination means, and a method of forcibly stopping the printing machine or preventing the printing from continuing. .
In the case of notification, there are a method using sound using a speaker, a method using a visual effect using light using a lighting device, and a method of displaying on a display medium such as an operation panel, as long as they affect the human senses. Any method may be used. Preferably, it affects the visual and auditory senses.
In addition to the method of completely stopping the printing machine, the method of making the printing machine stop or not continue is not limited to the case of stopping the supply of printing media (paper, film, etc.), or the impression cylinder or plate cylinder. May be physically separated (unplugged). According to the present invention, any method may be used as long as the printing state cannot be continued.

FIG. 5 shows the state of the relief printing press and the flexographic printing press.
The illumination means 6 and the imaging means 7 are attached to the plate cylinder 1, and the state where the plate surface in a state where the plate surface is thickened by the inking roller 5 is observed at a position immediately before printing is shown. As for the mounting angle between the illumination means and the imaging means, when the plate surface is mirror-finished, it is preferable to image with diffused light in order to reduce the influence of reflection.

In FIG. 6, it is a figure which shows a preferable state in an imaging means and illumination means attachment.
When the printing plate is curved, it is preferable to install the imaging means in a state perpendicular to the tangent of the printing plate, and to install the illumination means at 45 ° or 135 ° with respect to the tangent of the printing plate. It is possible to install not only one illumination means but also a plurality of illumination means.

  It is possible to observe the temperature state of the printing plate and the blanket by using a thermography capable of imaging heat in the imaging means, and it is also possible to control the printing pressure by observing the thermal expansion of the printing plate and the blanket.

FIG. 7 shows the state of the intaglio printing press.
It is possible to observe the state immediately before printing on the plate surface 1 from which excess ink has been wiped off by the wiping roller 8.
In the present invention, the imaging means and the illumination means are attached to the printing plate and the blanket, but it is also possible to take an image of the surface of the wiping roller. In this case, it is possible to detect an abnormal state (solvent contamination, liquid rising, etc.) due to wiping.

8 and 9 show the state of offset printing.
FIG. 8 shows a state where the printing plate is inspected, and FIG. 9 shows a state where a blanket is imaged.

FIG. 10 shows a state of the gravure printing machine.
A state immediately after the excess ink is scraped off by the doctor is imaged.

FIG. 11 shows the screen printing machine.
Unlike other printing presses, it is difficult to image a printing plate immediately before printing on a screen printing machine because the ink is attached and it is difficult, so imaging of the printing plate after the ink has been scraped off by a squeegee causes abnormal printing. Can be detected.
In this case, it is possible to detect plate clogging or image line configuration abnormality.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist.
In the present invention, the printing plate and the blanket can be inspected, respectively. If one printing machine has two kinds of printing methods called a hybrid printing machine (hybrid printing machine), It is possible to inspect the printing plate and the other to inspect the blanket. Of course, it is possible to inspect both of the printing presses having both the plate surface and the blanket, such as offset printing presses, even if they are not complex printing presses.

It is a schematic diagram of a printing plate and a blanket imaged in the visible light range. It is a schematic diagram of a printing plate and a blanket using infrared reflection / absorption ink. It is a schematic diagram of a printing plate and a blanket using ultraviolet emission characteristics. It is a schematic diagram regarding a threshold value. It is a schematic diagram regarding attachment of an imaging means and an illumination means. This is an example in which the present invention is used in a relief printing press or a flexographic printing press. This is an example in which the present invention is used in an intaglio printing press. This is an example in which the present invention is used in an offset printing press. This is an example in which the present invention is used in a blanket of an offset printing press. It is the example which used this invention with the gravure printing machine. This is an example in which the present invention is used in a screen printing machine.

Explanation of symbols

1 Plate (plate cylinder)
2 Impression cylinder 3 Printed material 4 Duct roller (ink fountain)
5 Inking roller 6 Illuminating means 7 Imaging means 8 Wiping roller 9 Water source roller 10 Blanket (Blank cylinder)
11 Doctor 12 Squeegee

Claims (7)

A method for inspecting a printing plate surface and / or blanket status immediately before printing online during printing,
Illuminating means for irradiating light to the printing plate surface and / or the surface of the blanket;
Image input means for inputting the printing plate surface and / or the blanket irradiated with light by the illumination means as image data;
Storage means for storing the image data;
Image collating means for comparing and collating the image data with a pre-registered printing plate surface or blanket reference image data;
Determination means for determining whether or not the image data collated by the image collating means matches the reference image data;
Control means for notifying printing stop and / or inconsistency information when it is determined by the determination means that they do not match (no);
A printing plate and / or blanket inspection method on a printing press. 2. The method for inspecting a printing plate and / or blanket on a printing press according to claim 1, wherein the light irradiated by the illumination means is one of visible light, UV light, and infrared light. 3. The printing plate and / or blanket printing according to claim 1, wherein the image input means uses at least one image input device among a CCD area camera, a CCD line camera, a color sensor, and a laser displacement sensor. On-machine inspection method. 4. A method for inspecting a printing plate and / or blanket on a printing press according to claim 1, wherein the image input means images a wavelength region of the light having a wavelength of 700 nm or more. In the image collating means, the image data and the reference image data are compared and collated by pattern matching with an arbitrary allowable value, or the image data and the reference image data are arbitrarily binarized, and the binarization processing is performed. 5. The printing plate and / or blanket printing machine according to claim 1, wherein at least one comparison / collation is performed among the comparison / collation for determining whether or not the number of subsequent pixels deviates from a predetermined allowable value. Top inspection method. In the determination means, as a determination standard that the image data and the reference image data do not coincide with each other, in the case of a printing plate surface, plate scratches, plate surface contamination, ink adhesion to a non-printed portion of the plate surface, wiping liquid rising to the plate surface , If at least one of the color difference, reprinting, and cracking of the printed part is against the standard,
In the case of a blanket, if at least one of the scratches on the blanket, dirt on the blanket, ink adhesion to the non-printed part of the blanket, color difference in the printed part, reprinting, and blanket breakage is against the standard,
6. A method for inspecting a printing plate and / or blanket on a printing press according to claim 1, wherein the disc surface and the blanket are determined not to coincide with each other. 7. The printing plate and / or blanket printing machine according to claim 1, wherein the control means uses at least one of image information, audio information, and character information for informing the mismatch information. Inspection method.

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