JP2019188678A - Registration control system, registration control method and printer - Google Patents

Abstract

To provide a registration control system for detecting a registration mark by inks having different clarity, and correcting registration deviation with a simple structure.SOLUTION: A registration control system comprises: an imaging device 2 for imaging a registration mark M by a transparent ink and an opaque ink formed on a transparent web W; a registration deviation measurement device for calculating a registration deviation amount used for correcting the registration deviation based on a position of the registration mark M on the image imaged by the imaging device 2. The imaging device 2 comprises: an illumination device 23a for radiating as illumination light a, red light to the web W; an illumination device 23b for radiating as illumination light b, blue light to the web W; and an area camera 21 for receiving illumination light transmitted the web W. The illumination device 23a is arranged so that a radiation direction of the illumination light a corresponds to an optical axis of the area camera 21, and the illumination device 23b is arranged so that the radiation direction of the illumination light b is deviated from the optical axis of the area camera 21.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a register control system and the like for correcting a misregistration when printing on a web with ink having different transparency.

  When performing multi-color printing on a web with a multi-color gravure printing machine, registration is performed in order to prevent the printing position of each color printing unit from shifting (registration misalignment) (see, for example, Patent Documents 1 and 2). .

  As a method to perform registration by automatic control, the registration mark printed by the printing unit is detected by a photoelectric sensor, and the deviation amount (registration deviation amount) from the target value of the registration mark is calculated based on the detected signal waveform. There is something to do. The calculated deviation amount is used for correcting the registration deviation in the printing unit, whereby printing by the printing unit is performed at a correct position on the web.

JP 2017-222139 Patent No. 4260870

  When inks with different transparency are used between the printing units of a multicolor gravure printing machine, the registration mark is printed with ink with different transparency, but if the transparency of the ink is high, the registration mark cannot be read by the sensor. In this case, it is not possible to correct misregistration by automatic control. Therefore, after manual adjustment by the operator at the initial stage of production, the misregistration is periodically confirmed visually and corrected.

  On the other hand, in Patent Document 2, a knife edge is disposed in the vicinity of the focal point of the light beam from the light source that has passed through the transparent web, the light beam traveling straight through the transparent web is blocked by the knife edge, and the light beam refracted by the transparent ink is allowed to pass. It is described that a registration mark printed with transparent ink by receiving a light beam is detected as a pulse. On the other hand, for register marks with visible ink with low transparency, the knife edge is moved so that the light beam traveling straight through the transparent web passes through the knife edge and is received, and the register mark that blocks the light beam on the transparent web is pulsed. Detect as.

  However, the method of Patent Document 2 requires a detection device with a complicated mechanism, and the cost increases. Further, the measurement of the misregistration amount by the pulse detected by the method of Patent Document 2 has a problem in terms of accuracy, and it is difficult to completely eliminate the adjustment work by the operator.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a registration control system and the like that can detect a registration mark with ink having different transparency with a simple configuration and thereby correct a registration deviation.

  According to a first aspect of the present invention for solving the aforementioned problems, there is provided a photographing device for photographing a plurality of registration marks having different transparency printed on a translucent web, and a position of the registration mark in a photographed image by the photographing device. A misregistration measuring device that calculates a misregistration amount used for correcting misregistration, and the imaging device includes a first illumination that irradiates the web with illumination light having a longer wavelength, and a shorter wavelength A second illumination that irradiates the web with illumination light; and a light receiving unit that receives illumination light of the first and second illuminations transmitted through the web. The first illumination includes illumination light The second illumination is arranged such that the illumination direction of the illumination light is deviated from the optical axis of the light receiving unit. Control system.

  In the present invention, when printing with inks having different transparency is performed on a translucent web, two illumination lights having different wavelengths are used as ink having relatively high transparency (referred to as transparent ink) and transparency. This is used for detecting a registration mark with a relatively low ink (referred to as opaque ink). Of these, long-wavelength illumination light passes through the web, travels straight, and is received by the light receiving unit. However, the registration mark appears as a dark region in the bright field by blocking the illumination light with a registration mark made of opaque ink. On the other hand, short-wavelength illumination light is scattered by the transparent ink on the web, and by receiving the scattered light, a registration mark by the transparent ink appears as a bright region in the dark field. As a result, it is possible to accurately detect both the registration marks using transparent ink and opaque ink with a simple configuration, calculate the amount of misregistration from the position, and use it to correct the misregistration. Matching can be performed. Also, by using scattered light, it is possible to read a registration mark with transparent ink having a level of transparency that has been difficult to read with a sensor. Further, in the present invention, the registration deviation amount can be calculated from the position of the registration mark in the two-dimensional captured image, so that the registration deviation amount can be measured with higher accuracy than in the case of detecting a one-dimensional registration mark by a pulse. .

For example, the first illumination emits red light as illumination light, and the second illumination emits blue light as illumination light. The misregistration measuring apparatus creates a grayscale image obtained by performing grayscale conversion on the red component of the photographed image and a grayscale image obtained by performing grayscale conversion on the blue component of the photographed image, and combining the two grayscale images. It is desirable to detect the register mark from the above.
By using red light and blue light as illumination light, it is possible to suitably detect the register mark by the transparent ink and the opaque ink. At this time, the register mark with transparent ink appears as a bright area in the dark field in the grayscale image obtained by converting the blue component of the photographed image to grayscale, and the register mark with opaque ink is a grayscale obtained by converting the red component of the photographed image to grayscale. Since it appears as a dark region in the bright field in the image, it is possible to detect a registration mark for each ink from a composite image obtained by combining these images.

It is preferable that the registration deviation measuring apparatus detects the registration mark by performing pattern matching.
In the present invention, a registration mark can be accurately detected from a two-dimensional captured image by pattern matching using an image processing method.

  According to a second aspect of the present invention, there is provided a step of photographing a plurality of registration marks with different transparency formed on a translucent web by a photographing device, and a registration deviation measuring device for registering marks in a photographed image by the photographing device. Calculating a misregistration amount used for correcting misregistration from a position, and the imaging device includes a first illumination that irradiates the web with illumination light having a longer wavelength, and illumination light having a shorter wavelength. A second illumination that irradiates the web, and a light receiving unit that receives illumination light of the first and second illuminations transmitted through the web, and the first illumination is irradiated with illumination light. The registration control method is characterized in that the direction is arranged so as to correspond to the optical axis of the light receiving unit, and the second illumination is arranged so that the irradiation direction of the illumination light deviates from the optical axis of the light receiving unit. It is.

  A third invention is a printing machine provided with the register control system of the first invention.

  According to the present invention, it is possible to provide a registration control system or the like that can detect a registration mark with ink having different transparency with a simple configuration and thereby correct a registration deviation.

The figure which shows the registration control system 1 and the gravure printing machine 100 provided with the same. An example of register mark M. The figure which shows the imaging device 2, R image, and B image. The figure which shows the hardware constitutions of the registration gap measuring device 3. The figure which shows the compensator roller 12. FIG. The figure which shows the function structure of the register control system. The flowchart which shows the register control method. The figure which shows the imaging device 2, R image, and B image. The figure shown about scattering of the illumination light b. Examples of R and B images and composite images. The figure which shows the vertexes m1-m3 of the registration mark M. FIG. FIG. 6 is a diagram illustrating a registration deviation amount Δd between adjacent registration marks M. The figure shown about the arrangement | positioning deviation amount (DELTA) d of the width direction of the web W, and the registration mark M. FIG. The figure which shows the registration control system 1a and the gravure printing machine 100 provided with the same. Misregistration amount between register adjacent mark M [Delta] d _a, shows a [Delta] d _b.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(1. Gravure printing machine 100)
FIG. 1 is a schematic configuration diagram illustrating a registration control system 1 and a gravure printing machine 100 including the registration control system 1 according to an embodiment of the present invention.

  The gravure printing machine 100 is a multicolor gravure printing machine, and includes a plurality of printing units 10 having a plate cylinder 11 for printing a register mark in addition to a pattern or the like. These printings are performed on a transparent web W having translucency, and while the web W is conveyed along the longitudinal direction, each printing unit 10 repeatedly prints a pattern, a register mark, etc. with different color inks. .

  In the present embodiment, a total of eight printing units 10 of 1U to 8U are provided in order from the upstream side to the downstream side in the conveyance direction of the web W indicated by the arrow A, of which 1U, 2U, 3U, and 7U Registration marks are printed by the four printing units 10. However, it is not limited to this.

  Each of the printing units 10 performs printing with ink having relatively high transparency (hereinafter referred to as transparent ink) and printing with ink having relatively low transparency (hereinafter referred to as opaque ink). In this embodiment, four registration marks are printed on the web W that has passed through the plate cylinder 11 of the last printing unit 10 (8U) using different inks with different transparency levels. Transparency is the ratio of the amount of transmitted light to the amount of incident light, and can be evaluated by the total light transmittance, for example. The total light transmittance can be measured by a measuring method defined in JIS K 7361. The transparency of the ink is determined by the ratio of the pigment or the medium in the ink. For example, the transparency is low when the ratio of the medium is low, and the transparency is high when the ratio of the medium is high.

  As the transparent ink, for example, an ink having a mass ratio of 96% or more to the whole ink can be used. Such an ink has a high total light transmittance, and it has been difficult to read a registration mark by a sensor. However, in the present embodiment, as described later, the scattered light b ′ of the illumination light b is used as described below. The registration mark can be read with transparent ink of a certain level of transparency. On the other hand, the opaque ink is, for example, an ink having a mass ratio of less than 96% with respect to the whole ink, and a register mark can be read by a conventional sensor. In this embodiment, illumination light a described later is used. By using it, the register mark is read with such ink with relatively low transparency.

(2. Register mark M)
FIG. 2 is an example of the registration marks M (M1 to M4) printed on the web W. In the present embodiment, the registration mark M is printed at the end of the web W in the width direction. The width direction of the web W (hereinafter referred to as the web width direction) is a direction orthogonal to the longitudinal direction of the web W in the plane, and corresponds to the left-right direction in FIG. The longitudinal direction of the web W (hereinafter referred to as the web longitudinal direction) corresponds to the vertical direction of FIG.

  The register marks M1 to M4 in FIG. 2 are printed by 1U, 2U, 3U, and 7U in the printing unit 10 shown in FIG. The registration marks M1 to M4 have the same shape and size, and the difference is the ink used for printing. In the present embodiment, the registration marks M1 to M4 have a right triangle shape, but the present invention is not limited to this. Further, the positions where the registration marks M1 to M4 are printed are not limited to the end portions in the web width direction.

  The registration marks M <b> 1 to M <b> 4 are set to be printed at predetermined positions when there is no registration deviation in each printing unit 10. In this example, the registration marks M1 to M4 are set so as to be arranged at a predetermined interval d2 along the longitudinal direction of the web. In addition, d1 of FIG. 2 is the length along the web longitudinal direction of the registration marks M1-M4.

(3. Register control system 1)
As shown in FIG. 1, the registration control system 1 according to the present embodiment includes an imaging device 2, a registration deviation measuring device 3, a registration control device 4, an encoder 5, and the like.

  The photographing apparatus 2 photographs the registration mark M on the web W while the web W is being conveyed. In the present embodiment, the photographing apparatus 2 is configured to perform photographing on the downstream side of the plate cylinder 11 of the last printing unit 10. . A photographed image (still image) taken by the photographing device 2 is input to the misregistration measuring device 3.

  FIG. 3 is a diagram showing the photographing apparatus 2. In the present embodiment, the photographing apparatus 2 includes an area camera 21 provided on one side with respect to the plane of the web W and illuminations 23a and 23b provided on the opposite side. FIG. 3 omits the registration mark M on the web W to explain the basic configuration of the photographing apparatus 2. The case where the registration mark M is on the web W will be described later.

  The area camera 21 is a light receiving unit that receives the illumination light irradiated from the illuminations 23a and 23b and transmitted through the web W to capture the web W. In this embodiment, a color camera is used to acquire a color image (RGB image in this embodiment) obtained by photographing the web W. The area camera 21 has an installation condition that provides a field of view in which at least two adjacent registration marks M (see FIG. 2) can be accommodated in one image with a resolution at which a desired accuracy can be obtained. Note that a line camera may be used as the light receiving unit instead of the area camera 21. The line camera obtains a photographed image of the web W in a predetermined range by continuously photographing one line in the web width direction for a certain period of time while the web W is being conveyed, and the resolution can be higher than that of the area camera 21. And it is excellent in that the illuminations 23a and 23b can be made small and the degree of freedom of installation is increased. However, there is a possibility that an object to be photographed in the photographed image expands and contracts due to a change in the conveyance speed of the web W, and the area camera 21 that can obtain a photographed image of the web W in a predetermined range with one shot has such a fear. It is suitable for dimension measurement because there is no point. In addition, the area camera 21 is advantageous in that the apparatus cost can be reduced.

  The illumination 23a (first illumination) irradiates the web W with red light as the illumination light a, and the illumination light a is irradiated so that the illumination light a that has passed through the web W and travels straight enters the area camera 21. The direction is provided corresponding to the optical axis c of the area camera 21. The R image in FIG. 3 is a grayscale image obtained by performing grayscale conversion on the R component (red component) of the photographed image obtained by photographing the web W with the area camera 21, and has a bright bright field as a whole. As the red light, for example, light having a wavelength of 620 nm or more and 750 nm or less is used.

  In the present embodiment, the irradiation direction of the optical axis c of the area camera 21 and the illumination light a corresponds to the normal direction of the web W, but is not limited thereto. The irradiation direction of the optical axis c of the area camera 21 and the illumination light a may be shifted within a range of about 45 ° with respect to the normal direction of the web W.

  The illumination 23b (second illumination) irradiates the web W with blue light as the illumination light b, and the illumination light b that passes straight through the web W does not enter the area camera 21 and is a registration mark described later. The irradiation direction of the illumination light b is shifted from the optical axis c of the area camera 21 so as to be inclined with respect to the optical axis c so that the scattered light at M enters the area camera 21. The deviation angle between the irradiation direction of the illumination light b and the optical axis c of the area camera 21 is not particularly limited as long as the above conditions are satisfied. In this embodiment, since the optical axis of the area camera 21 corresponds to the normal direction of the web W, the irradiation direction of the illumination light b is also deviated from the normal direction of the web W.

  The B image in FIG. 3 is a grayscale image obtained by performing grayscale conversion on the B component (blue component) of the photographed image obtained by photographing the web W with the area camera 21, and the whole becomes a dark dark field. As the blue light, for example, light having a wavelength of 450 nm to 495 nm is used.

  The registration deviation measuring device 3 calculates a registration deviation amount used for correcting the registration deviation in the printing unit 10 from the position of the registration mark M in the photographed image obtained by photographing the registration mark M on the web W by the photographing device 2. is there.

  FIG. 4 is a diagram illustrating a hardware configuration of the misregistration measuring apparatus 3. As shown in FIG. 4, the misregistration measuring apparatus 3 can be realized by a computer configured by connecting a control unit 31, a storage unit 32, a display unit 33, an input unit 34, a communication control unit 35, and the like by a bus or the like. However, the present invention is not limited to this, and various configurations can be taken as appropriate.

  The control unit 31 includes a CPU, a ROM, a RAM, and the like. The CPU calls and executes a program related to processing of the misregistration measuring apparatus 3 stored in a storage medium such as the storage unit 32 and the ROM in a work area on the RAM. ROM is a non-volatile memory, and permanently stores programs such as boot programs and BIOS, and data. The RAM is a volatile memory, and temporarily stores programs and data loaded from the storage unit 32, the ROM, and the like, and includes a work area used by the control unit 31 for performing various processes.

  The storage unit 32 is a hard disk drive, a solid state drive, a flash memory, or the like, and stores a program executed by the misregistration measuring device 3 during processing to be described later, data necessary for program execution, an OS, and the like. These programs and data are read and executed by the control unit 31 as necessary.

The display unit 33 includes a liquid crystal display or the like.
The input unit 34 inputs various settings to the misregistration measuring apparatus 3.
The communication control unit 35 is a communication interface that mediates wireless communication.

  In addition to calculating the misregistration amount as described above, the misregistration measuring apparatus 3 displays the system operation status and the misregistration correction status on the display unit 33, and various types necessary for calculating the misregistration amount by the input unit 34. Accept data input. Data necessary for calculating the registration deviation amount includes the number of printing units 10 to be used, the width of the web W, the circumference of the plate cylinder 11, the setting of the registration mark M (shape, position, etc.). When each data is held on the gravure printing machine 100 side, these data may be automatically input from the gravure printing machine 100.

  The registration control device 4 controls the printing unit 10 based on the registration deviation amount calculated by the registration measurement device 3 and corrects registration (registering) so that the registration deviation amount becomes zero.

  For example, the plate cylinder 11 of each printing unit 10 is a sectional drive system that can be driven individually, and the registration control device 4 shifts the position of the plate cylinder 11 relative to the rotation axis in the rotation direction of the plate cylinder 11 based on the amount of registration deviation. The phase of the plate cylinder 11 is adjusted individually. Alternatively, as shown by an arrow B in FIG. 5, the web W in the printing unit 10 may be controlled by controlling the vertical position of the compensator roller 12 in front of the plate cylinder 11 of the printing unit 10.

  The encoder 5 detects the rotational speed (web W conveyance speed) of the plate cylinder 11 of the gravure printing machine 100. For example, the encoder 5 is provided on the rotating shaft of the plate cylinder 11, but may be installed on a rotating body (for example, a rotating shaft of a motor) that rotates once when the plate cylinder 11 rotates once in the drive control unit of the gravure printing machine 100. Good.

  In the present embodiment, the encoder 5 detects the rotational speed of the plate cylinder 11 of the printing unit 10 (U1) at the foremost stage, but the rotational speed of other plate cylinders 11 may be detected. Based on the rotational speed detected by the encoder 5, the imaging device 2 captures the web W at an appropriate timing at which the registration mark M can be captured.

  FIG. 6 is a diagram illustrating a functional configuration of the register control system 1. As shown in the figure, the registration deviation measuring device 3 of the registration control system 1 includes an image processing unit 301, a calculation unit 302, and the like.

  The image processing unit 301 detects the position of the register mark M from a captured image obtained by capturing the register mark M on the web W with the image capturing device 2.

  The calculation unit 302 calculates the amount of misregistration used for correcting the misregistration from the position of the registration mark M detected by the image processing unit 301.

(4. Registration control method)
FIG. 7 is a flowchart showing the register control method of the present embodiment. The flow of the present embodiment is executed during printing on the web W by the gravure printing machine 100.

  In the present embodiment, first, the photographing apparatus 2 photographs the registration mark M on the web W being conveyed (S1). In the present embodiment, the registration mark M is printed with the transparent ink and the opaque ink as described above, and the photographing apparatus 2 is configured so that any of these registration marks M can be suitably detected.

  That is, when the registration mark M made of opaque ink is formed on the web W, the illumination light a from the illumination 23a is blocked by the registration mark M as shown in FIG. A register mark M appears as a dark area in the bright field. The registration mark M also blocks the illumination light b from the illumination 23b, but the registration mark M does not appear in the image because the B image is a dark field.

  On the other hand, when the registration mark M made of transparent ink is formed on the web W, in this embodiment, the illumination light b from the illumination 23b is scattered by the registration mark M as shown in FIG. When the part of the scattered light b ′ enters the area camera 21, the registration mark M appears as a bright region in the dark field in the B image.

  On the other hand, since the illumination light a from the illumination 23a passes through the registration mark M in the same manner as the surrounding web W and travels straight, the registration mark M does not appear in the R image.

  In the present embodiment, by using blue light having a short wavelength as the illumination light b, the illumination light b is likely to be scattered (difficult to diffract) by fine particles p such as pigments in the register mark M as shown in FIG. Therefore, the registration mark M can be detected by the scattered light b ′. On the other hand, as the illumination light a from the illumination 23a, red light having a long wavelength that is easily diffracted (difficult to scatter) is used. Therefore, scattering by the microparticles p hardly occurs, and the illumination light a is the registration mark M as described above. Go straight on.

  A photographed image obtained by photographing the registration mark M on the web W by the photographing apparatus 2 is input to the registration deviation measuring apparatus 3. The registration deviation measuring device 3 creates an R image obtained by performing gray scale conversion on the R component of the photographed image and a B image obtained by performing gray scale conversion on the B component of the photographed image (S2).

  FIG. 10A is an example of the R image and the B image. As described above, in this embodiment, the registration mark M by the opaque ink appears as a dark region in the bright field in the R image, and the registration mark by the transparent ink. M appears as a bright region in the dark field in the B image.

  The registration deviation measuring device 3 combines the R image and B image (grayscale image) created in S2 to create a composite image (S3). Here, after the brightness of one of the R image and the B image is inverted, this is combined with the other image. An example of the composite image is shown in FIG. FIG. 9B shows an example in which the brightness of the B image is inverted and then combined with the R image.

  The registration deviation measuring device 3 detects the registration mark M from the composite image (S4). In the present embodiment, the registration mark M is detected by performing pattern matching using the shape of the registration mark M as a template.

  The registration deviation measuring device 3 determines whether or not the number of registration marks M necessary for calculating the registration deviation amount has been detected (S5). If the required number of registration marks M has not been detected (S5; No), photographing is performed. A control signal is transmitted to the apparatus 2, and the photographing timing is changed to perform photographing again (S9).

  In the present embodiment, the number of registration marks M necessary for calculating the registration deviation amount is two. For example, when only one registration mark M can be detected from the composite image, at least two registration marks M are changed by changing the shooting timing. The registration mark M is detected from the composite image.

  When the necessary number of registration marks M can be detected (S5; Yes), the registration deviation measuring device 3 detects the position of each registration mark M (S6), and the longitudinal direction of the web from the position coordinates of the registration mark M Is calculated (S7).

  In the present embodiment, the position of the registration mark M is detected from the position coordinates of the vertex, and the registration deviation amount is calculated using this. As shown in FIG. 11, the registration mark M has three vertices m1 to m3. Here, the vertex on the side where the pattern part of printing and the registration mark M are unlikely to overlap is used.

  For example, when there is a pattern portion on the right side of the registration mark M shown in FIG. 11, either the left apex m1 or m2 of the registration mark M is detected, and the position coordinate is used for calculating the registration deviation amount. However, which vertex is detected is not particularly limited, and the position of the registration mark M can be detected by position coordinates other than the vertex (for example, position coordinates of the center of gravity).

  The registration deviation amount is calculated as a deviation amount Δd from the target value (d1 + d2) of the pitch d between the vertices of adjacent registration marks M as shown in FIG.

  In the present embodiment, until all the registration deviation amounts Δd between adjacent registration marks M are calculated (S8; No), the imaging timing is changed and the imaging device 2 captures the web W (S9). The flow of S1 to S7 is repeated. In the example of FIG. 12A, the registration marks M1 and M2 are first photographed to calculate the registration deviation amount Δd of the registration mark M2 with respect to the registration mark M1. For example, in the next photographing, the registration marks M2 and M3 are photographed. Then, as shown in FIG. 12B, a registration deviation amount Δd (0 in this example) of the registration mark M3 with respect to the registration mark M2 is calculated.

  When all the registration deviation amounts Δd between the adjacent registration marks M are thus calculated (S8; Yes), the registration deviation measuring device 3 transmits all the calculated registration deviation amounts Δd to the registration control device 4, and the registration control device 4 Based on the received misregistration amount Δd, the misregistration of the printing unit 10 is corrected (S10).

  In S10, the registration control device 4 transmits a control signal to the printing unit 10 to correct the registration deviation of the printing unit 10 and performs registration as described above so that the registration deviation amount Δd becomes zero. . In the present embodiment, the registration deviation is corrected for the 2U, 3U, and 7U printing units 10 described above. For example, the registration deviation of the printing unit 10 in which the registration deviation amount Δd of the registration mark M2 with respect to the registration mark M1 is 2U is corrected. Is used for correcting the registration deviation of the printing unit 10 in which the registration deviation amount Δd of the registration mark M3 with respect to the registration mark M2 is 3U.

  While the misregistration correction is performed in this way, the display unit 33 of the misregistration measuring apparatus 3 displays the system operation status and the misregistration correction status as described above. As the misregistration correction status, for example, a temporal change in the misregistration amount of the printing unit 10 accompanying the misregistration correction is shown as a graph.

  As described above, according to the present embodiment, when printing with inks having different transparency is performed on the translucent web W, two illumination lights a (red light) having different wavelengths are used. Illumination light b (blue light) is used to detect the registration mark M with transparent ink and opaque ink. Of these, the illumination light a passes through the web W and travels straight and is received, but the registration mark M appears as a dark region in the bright field when the illumination light a is blocked by the registration mark M made of opaque ink. On the other hand, the illumination light b is scattered by the transparent ink on the web W, and by receiving the scattered light b ', the registration mark M made of the transparent ink appears as a bright region in the dark field.

  As a result, both the registration mark M made of transparent ink and opaque ink can be accurately detected with a simple configuration, and the registration deviation amount Δd is calculated from the position and used for correction of the registration deviation. Registration can be performed without any problems. Further, by using the scattered light b ', it is possible to read the registration mark with a transparent ink having a level of transparency that has been difficult to read with a sensor. In this embodiment, the registration deviation amount Δd can be calculated from the position of the registration mark M in the two-dimensional captured image. Therefore, the registration deviation amount can be detected with higher accuracy than in the case of detecting a one-dimensional registration mark using a pulse. Can measure.

  Further, in the present embodiment, by using red light as the illumination light a and blue light as the illumination light b, it is possible to suitably detect the registration mark M made of transparent ink and opaque ink. At this time, the registration mark M by the transparent ink appears as a bright area in the dark field in the B image, and the registration mark M by the opaque ink appears as a dark area in the bright field in the R image. A registration mark M by each ink can be detected from the synthesized image.

  However, light having a wavelength longer than that of the illumination light b may be used as the illumination light a, and light having a wavelength shorter than that of the illumination light a may be used as the illumination light b, and the illumination light a and b may be the red light and blue light described above. There is no limit. For example, light having a shorter wavelength than blue light can be used as the illumination light b. The illumination lights a and b do not have to be in the visible light range. For example, infrared light can be used as the illumination light a and ultraviolet light can be used as the illumination light b. In this case, however, an imaging device having sensitivity in the ultraviolet region and the infrared region is separately required, and the cost is increased. In this respect, the above-described embodiment in which only one area camera 21 that is a color camera is used is used. It is advantageous.

  In the present embodiment, the registration mark M can be accurately detected from a two-dimensional captured image by pattern matching using an image processing method.

  However, the present invention is not limited to this. For example, in this embodiment, the area camera 21 that captures a color image is used as the light receiving unit. Instead, an optical sensor that receives only the illumination light a (red light) and only the illumination light b (blue light) are received. An optical sensor may be used. In this case, an image obtained by receiving red light and blue light by each sensor is converted to gray scale, and these images are combined. However, the use of the area camera 21 has an advantage that the configuration is simple with only one light receiving unit.

  In this embodiment, the four registration marks M1 to M4 are formed on the web W. However, the present invention is not limited to this, and a plurality of registration marks M having different levels of transparency are formed on the web W. If you do. Further, in the present embodiment, the area camera 21 captures two registration marks M adjacent in the longitudinal direction of the web. However, it may be possible to capture three or more registration marks M adjacent in the longitudinal direction of the web. As a result, the number of photographing can be reduced.

  In this embodiment, the registration deviation amount Δd in the web longitudinal direction is calculated and the registration deviation is corrected. However, as shown in FIG. 13A, the web width direction between the registration marks M adjacent in the web longitudinal direction. The misregistration amount Δd may be calculated to correct the misregistration in the web width direction. For example, the registration deviation in the web width direction can be corrected by moving the plate cylinder 11 and other transport rolls in the web width direction.

  In the present embodiment, the registration marks M1 to M4 are printed in order in the web longitudinal direction. However, as shown in FIG. 13B, a plurality of registration marks M1 are printed at intervals, and each registration mark M1 is printed. Later, the registration marks M2 to M4 may be sequentially printed so that all the registration marks M1 and the registration marks M2 to M4 are arranged at a predetermined interval d2. In this case, the registration deviation amounts of the registration marks M2 to M4 with respect to the registration mark M1 can be calculated and used for correcting the registration deviation.

  Further, as shown in FIG. 13C, the registration marks M (M1 to M5) may be printed so as to be aligned in the web longitudinal direction and the web width direction. By photographing so that these registration marks M1 to M5 fit in one photographed image, the registration deviation amounts of the registration marks M2 to M5 with respect to the registration mark M1 can be calculated and used for correcting the registration deviation. .

  Further, in the present embodiment, the photographing apparatus 2 is provided on the downstream side of the plate cylinder 11 of the last printing unit 10, but as shown in FIG. 14, each of the printing units 10 excluding the printing unit 10 in the foremost stage. An imaging device 2 is provided on the downstream side of the plate cylinder 11 so as to calculate a registration deviation amount Δd between the printing unit 10 and a registration mark M printed by the preceding printing unit 10 and correct the registration deviation. Also good.

For example, based on the photographed image from the photographing apparatus 2 provided on the downstream side of the plate cylinder 11 of the printing unit 10 of 2U, the misregistration amount [Delta] d _a register mark M2 for the register mark M1 as shown in FIG. 15 (a) Thus, the misregistration of the 2U printing unit 10 can be corrected.

In parallel with this, the photographing apparatus 2 provided on the downstream side of the plate cylinder 11 of the last printing unit 10 photographs the registration marks M1 and M2 on the web W until the above correction is performed. From the image, it is also possible to calculate the misregistration amount and correct the misregistration of the 2U printing unit 10 based on the misregistration amount as described above. However, as shown in FIG. 15 (b), misregistration amount at this time, as the initial target value a target value a value obtained by adding the above-mentioned misregistration amount [Delta] d _a to (d1 + d2) (d1 + d2 + Δd a), the it is desirable to calculate a misregistration amount [Delta] d _b with respect to the target value, thereby not to perform a correction that overlaps with the correction described above.

  In the present embodiment, an example of the gravure printing machine 100 has been described. However, the application target of the registration control system and the like of the present invention is not limited to this, and a plurality of registrations having different transparency levels on the translucent web W. Any printer that prints the mark M may be used.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

DESCRIPTION OF SYMBOLS 1, 1a: Registration control system 2: Imaging device 3: Registration deviation measuring device 4: Registration control device 5: Encoder 10: Printing unit 11: Plate cylinder 12: Compensator roller 21: Area camera 23a, 23b: Illumination 100: Gravure printing Machine 301: Image processing unit 302: Calculation unit

Claims (6)

A photographing device for photographing a plurality of registration marks with different transparency printed on a translucent web;
A misregistration measuring device that calculates a misregistration amount used for correcting misregistration from a position of a registration mark in a photographed image by the photographing device;
Have
The imaging apparatus includes: a first illumination that irradiates the web with illumination light having a longer wavelength; a second illumination that irradiates the web with illumination light having a shorter wavelength; and the first that transmits the web. A light receiving portion that receives illumination light of the second illumination,
The first illumination is arranged such that an illumination direction of illumination light corresponds to an optical axis of the light receiving unit,
The register control system, wherein the second illumination is arranged such that an illumination direction of illumination light is deviated from an optical axis of the light receiving unit.   The registration control system according to claim 1, wherein the first illumination emits red light as illumination light, and the second illumination emits blue light as illumination light.   The misregistration measuring apparatus creates a grayscale image obtained by performing grayscale conversion on the red component of the photographed image and a grayscale image obtained by performing grayscale conversion on the blue component of the photographed image, and combining the two grayscale images. 3. The register control system according to claim 2, wherein the register mark is detected from the register.   The registration control system according to claim 1, wherein the registration deviation measuring device detects the registration mark by performing pattern matching. Photographing a plurality of registration marks with different transparency formed on a translucent web by a photographing device;
A step of calculating a misregistration amount used for correction of misregistration from a position of a registration mark in a photographed image by the photographing device by a misregistration measuring device;
Have
The photographing apparatus includes: a first illumination that irradiates the web with illumination light having a longer wavelength; a second illumination that irradiates the web with illumination light having a shorter wavelength; and the first illumination that is transmitted through the web. A light receiving portion that receives illumination light of the second illumination,
The first illumination is arranged such that an illumination direction of illumination light corresponds to an optical axis of the light receiving unit,
The registration control method, wherein the second illumination is arranged such that an illumination direction of illumination light is shifted from an optical axis of the light receiving unit.   A printing machine comprising the register control system according to any one of claims 1 to 4.