JP2010066822A - Inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect a printed information element easily in a short time period. <P>SOLUTION: A print system forms a printed image on a print sheet according to a source image data 671. By means of a plurality of imaging units 71 for respectively imaging a plurality of imaging areas partially overlapped on the print sheet, a plurality of imaged images of high resolution are obtained. An area cutout unit 62 obtains partial area images by cutting out a partial area, at least including a portion of an information element of a letter, numeral, symbol or code pattern, in the plurality of imaged images. When a plurality of partial area images each partially indicating an identical information element are obtained, an image synthesis unit 64 generates an information element image by synthesizing the partial area images, and an information comparison unit 65 compares source information 673, which is represented by information elements when the source image data 671 is generated, with information obtained from the information element image. As a result, the print system can inspect the information element easily in a short time period. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inspection apparatus that inspects a printed image formed on a print medium.

  In recent years, individual information is printed (that is, variable information is printed) on each printing paper (each part corresponding to one page when the printing paper is roll paper) using an ink jet printing apparatus or the like. Things have been done. In this case, information elements such as characters, numbers, barcodes or two-dimensional codes may be included in the print image as representing character information or numerical information, and the information elements in such a print image are inspected. Things are also done. For example, Japanese Patent Application Laid-Open No. 2004-228561 discloses a method of performing pass / fail determination by recognizing and decoding a print character printed on paper, converting it into a character code, and comparing and comparing the character code to be printed. Japanese Patent Application Laid-Open No. 2004-228561 also discloses a method of specifying an accurate reading position in camera image data by reading a reference mark in page units with a camera during paper conveyance.

In the inspection of various objects, a plurality of imaging units are provided to image a wide range of the inspection object, which enables high-accuracy inspection based on high-resolution images (for example, Patent Documents 2 to 4).
JP 2006-79571 A JP 2003-98106 A JP 2004-170394 A JP 2002-131033 A

  By the way, when inspecting an information element in a print image, it is necessary to obtain a high-resolution image showing the entire information element, but the position of the information element is not necessarily constant in a variable information print image, It is not easy to acquire an image showing the entire information element. Although it is conceivable to change the position of the imaging unit for each print image in accordance with the position of the information element, it takes some time for the imaging unit to move, and it is difficult to inspect the information element in a short time. Become. Further, when there are a plurality of information elements in the print image, depending on the positions of the plurality of information elements, the entire information elements cannot be included in one high-resolution image.

  The present invention has been made in view of the above problems, and an object thereof is to easily inspect information elements in a short time.

  The invention according to claim 1 is an inspection apparatus for inspecting an information element that is at least one character, number, symbol, or code pattern included in a print image formed on a print medium according to original image data. A plurality of imaging units that respectively capture a plurality of imaging regions that partially overlap on a medium to obtain a plurality of captured images, and a partial region that includes at least a part of one information element in the plurality of captured images Region extraction unit for acquiring at least one partial region image, and when a plurality of partial region images each partially representing the information element are acquired, overlapping portions in the plurality of partial region images are obtained. An image composition unit that generates an information element image indicating the entire information element by combining the plurality of partial region images while overlapping, and an original image data Provided the original information which is character information or numerical information represented in the information element when formed, and the information comparison unit for comparing the acquired information is character information or numerical information acquired from the information element image.

  A second aspect of the present invention is the inspection apparatus according to the first aspect, further comprising a movement mechanism that continuously moves the print medium in a movement direction parallel to a print surface of the print medium, The image pickup unit is a plurality of line sensors arranged in a width direction parallel to the print surface and perpendicular to the movement direction, and the plurality of image pickup regions extend in the movement direction and are arranged in the width direction. A plurality of strip-shaped regions are formed, and two strip-shaped regions adjacent in the width direction partially overlap with each other in the width direction to form an overlapping imaging region.

  A third aspect of the present invention is the inspection apparatus according to the second aspect, wherein the print medium is in a sheet shape, and the length in the width direction of the overlapping imaging region due to flapping of the print medium in the course of movement. And when the image composition unit overlaps overlapping portions in the plurality of partial region images, a search for a width equal to or larger than the variation width in the width direction of the overlapping imaging region with respect to a direction corresponding to the width direction is performed. Set the range.

  A fourth aspect of the present invention is the inspection apparatus according to the second or third aspect, wherein the printing apparatus that prints the print image and the plurality of imaging units are arranged along a movement path of the print medium. .

  A fifth aspect of the present invention is the inspection apparatus according to any one of the second to fourth aspects, wherein the information element is a barcode in which a plurality of bars are arranged in the moving direction, and the region cutting is performed. When the plurality of partial region images are acquired at the exit, the one having the maximum width in the direction corresponding to the width direction among the plurality of partial region images, or the portion indicating the barcode The apparatus further includes a barcode determination unit that outputs the information element image having the maximum width in the direction corresponding to the width direction to the information comparison unit.

  A sixth aspect of the present invention is the inspection apparatus according to any one of the first to fifth aspects, wherein the print medium is printing paper, and the print image is formed by an ink jet printing apparatus.

  According to the present invention, even when a plurality of captured images each partially showing the same information element are acquired, the information element can be easily inspected in a short time.

  According to the third aspect of the present invention, an information element image can be generated with high accuracy even when the printing medium in the process of fluttering. In the fifth aspect of the present invention, the information element has a plurality of bars arranged in the moving direction. In the case of a barcode, the information element can be examined in a shorter time.

  FIG. 1 is a diagram showing a configuration of a printing system 1 according to an embodiment of the present invention. The printing system 1 prints an image including variable information on the printing paper 9 (that is, performs variable printing) and automatically inspects the printed image (printing image) on the printing paper 9. The printing system 1 in FIG. 1 is formed on an ink jet printing apparatus 11, a computer 5 connected to the printing apparatus 11, and a printing surface of the printing paper 9 (surface on the (+ Z) side in FIG. 1). An inspection unit 6 for inspecting the printed image is provided. The printing apparatus 11 moves the printing paper 9 in the Y direction in FIG. 1 below the head unit 2 that discharges fine droplets of ink toward the printing paper 9 and below the head unit 2 ((−Z) side). And a main body control unit 4 connected to the head unit 2 and the paper feed mechanism 3.

  The paper feed mechanism 3 includes two belt rollers 31 connected to a motor (not shown), and a belt 32 hung between the two belt rollers 31. The printing paper 9 is a roll paper which is a continuous paper having a predetermined width, and is guided and held on the belt 32 via a roller 33 provided above the belt roller 31 on the (+ Y) side. It passes below the head unit 2 and moves to the (−Y) side. The belt roller 31 of the paper feed mechanism 3 is provided with an encoder (not shown). The moving mechanism for continuously moving the printing paper 9 in the moving direction parallel to the printing surface may be realized by other configurations such as a roller-only transport mechanism.

  The head unit 2 is provided with a plurality of ejection units 21 that eject inks of cyan (C), magenta (M), yellow (Y), and black (K), respectively. Arranged. FIG. 2 is a bottom view of one ejection unit 21. In FIG. 2, the moving direction (that is, the Y direction) of the printing paper 9 with respect to the head unit 2 is illustrated vertically.

  As shown in FIG. 2, each ejection unit 21 has a plurality of heads 211 perpendicular to the moving direction (Y direction) of the printing paper 9 and parallel to the printing surface of the printing paper 9 (X in FIGS. 1 and 2). And is a direction corresponding to the width of the printing paper 9, and is hereinafter referred to as a “width direction”), and is arranged in a zigzag pattern. An array is formed at a constant pitch in the direction. The head 211 is provided with a piezoelectric element for each ejection port 212, and by driving the piezoelectric element, micro droplets of ink are ejected from the ejection ports 212 toward the printing paper 9. Actually, the distance between the two heads 211 adjacent to each other in the width direction is also accurately adjusted, so that all the discharge ports 212 included in the discharge unit 21 have the width of the print area on the print paper 9 in the width direction. The printing system 1 is arranged at a constant pitch throughout, and the printing system 9 can perform high-speed printing only by passing the printing paper 9 under the head unit 2 once (so-called one-pass). . In FIG. 2, only five ejection ports 212 are shown in each head 211, but in reality, a large number of ejection ports 212 are formed in an array. The head 211 may be of a type that ejects minute droplets by heating ink.

  In the printing system 1 of FIG. 1, in parallel with the movement of the printing paper 9 in the (−Y) direction by the paper feeding mechanism 3, the main body control unit 4 selects an image to be printed (hereinafter referred to as “original image”). By controlling the ejection of ink from the heads 211 of each color according to the data, a color print image is formed on a portion on the print paper 9 corresponding to one page of the printed matter. In this manner, the inkjet printing apparatus 11 in the printing system 1 performs variable printing that forms a print image including variable information.

  On the (−Y) side of the head unit 2, an illumination unit 72 that irradiates light for illumination on a print image immediately after being formed on the print paper 9, and a width of the print image taken at a predetermined resolution A plurality of imaging units 71 (only one imaging unit 71 is illustrated in FIG. 1) arranged in the direction are provided, and images acquired by each imaging unit 71 (hereinafter “captured images”). Data) is output to the inspection unit 6. Here, the image resolution is the number of pixels per unit distance on the printing paper 9 in each of the movement direction and the width direction of the printing paper 9. In the image in the following description, it is assumed that the row direction and the column direction, which are pixel arrangement directions, correspond to the width direction and the movement direction, respectively.

  FIG. 3 is a diagram illustrating an arrangement of the plurality of imaging units 71 when viewed along the moving direction. As described above, the plurality of imaging units 71 shown in FIG. 3 (only two imaging units 71 are illustrated in FIG. 3) are arranged in the width direction perpendicular to the moving direction. Is a line sensor in which a plurality of light receiving elements are arranged in the width direction. The imaging range in the width direction of two adjacent imaging units 71 (indicated by an arrow with a symbol R1 in FIG. 3) partially overlaps. Specifically, the imaging unit 71 on the (+ X) side. The (−X) side end of the imaging range R1 and the (+ X) side end of the imaging range R1 of the (−X) side imaging unit 71 form an overlapping imaging range R2. In the printing system 1, the plurality of imaging ranges R <b> 1 of the plurality of imaging units 71 extend over the entire width in the width direction on the printing paper 9. The plurality of imaging units 71 are fixed relatively to the paper feed mechanism 3.

  In the printing system 1, since the paper feeding mechanism 3 continuously moves the printing paper 9 in the moving direction, (two-dimensional) images are acquired by the imaging units 71 that are line sensors. As described above, the imaging area A1 on the printing paper 9 captured by each imaging unit 71 is a band-like area extending in the movement direction (Y direction), and a plurality of band-like areas (imaging area A1) respectively corresponding to the plurality of imaging units 71. ) Are arranged in the width direction. In addition, two band-like regions adjacent in the width direction form an overlapping imaging region A2 (a region indicated by parallel diagonal lines in FIG. 4) that partially overlaps in the width direction. Actually, in the inspection unit 6, the data (lines of one row) sequentially input from the imaging unit 71 is a portion corresponding to one page of the printed matter in the column direction corresponding to the moving direction (that is, one print Each image) is divided and treated as one captured image.

  FIG. 5 is a block diagram illustrating a functional configuration related to the inspection of a print image in the printing system 1. In FIG. 5, the functional configuration of the inspection unit 6 is surrounded by a broken line. The inspection unit 6 includes, in each captured image, a partial region including at least a part of one information element (that is, a region including the entire portion of the information element appearing in the captured image, and the entire information element is included in the captured image. When the symbol appears, a region cutout unit 62 that cuts out a region including the entire information element and obtains a partial region image, and a barcode determination unit 63 that determines whether the information element is a specific barcode. An image that generates an information element image showing the entire information element when a plurality of partial area images showing the partial area of the same information element are acquired from a plurality of captured images acquired by the plurality of imaging units 71 A combining unit 64, an information comparing unit 65 for inspecting the information element image, and a storage unit 61 for storing information such as inspection results are provided. In the present embodiment, the inspection unit 6 is realized by (another) computer, but of course, all or a part of the inspection unit 6 may be realized by a dedicated electric circuit.

  Here, the information element will be described. Information elements are shown in FIG. Characters and symbols such as alphabets shown in A, or FIG. Numbers such as Arabic numerals shown in B, or FIG. A thru | or FIG. The bar code shown in FIG. A thru | or FIG. A code pattern such as a two-dimensional code shown in C, which represents character information or numerical information. When the information element is a character, number, or symbol, the information element in the captured image is read as character information or numerical information by OCR (Optical Character Recognition), and when the information element is a code pattern, the captured image The information elements inside are decoded and read as character information or numerical information. In the computer 5 of the printing system 1, at least one information element is included in each original image corresponding to one page of the printed matter. Note that FIG. A thru | or FIG. C corresponds to the standards of EAN128, Code39, and NW7, respectively, and FIG. A thru | or FIG. C corresponds to the standards of QR Code (registered trademark), Data Matrix, and PDF417, respectively. The code pattern may be other than a bar code or a two-dimensional code as long as it is a graphic representing character information or numerical information.

  Further, as described above, each captured image is an image divided into portions corresponding to one page of the printed matter (that is, the print image) in the column direction corresponding to the movement direction, and at least one print image is included in the print image. Since the information element is included, the region cutout unit 62 cuts out at least one partial region including at least a part of each information element in the plurality of captured images acquired almost simultaneously by the plurality of imaging units 71. One partial area image is acquired.

  Next, an operation in which the printing system 1 prints an image on the printing paper 9 and inspects the printed image will be described with reference to FIG. In the computer 5 of the printing system 1 in FIG. 1, first, data of an original image to be printed (original image data) is generated and prepared (step S11). At this time, predetermined character information or numerical information (for example, when the original image indicates a receipt, it is character information indicating a customer's name or numerical information indicating a receipt amount, and is hereinafter referred to as “original information”. ) Is represented in the information element and included in the original image. The computer 5 also generates region data indicating a region (range) in which the information element is arranged in the original image in association with each information element, and a set of the original image data 671, the region data 672, and the original information 673 is an image. Information 67 is output to the inspection unit 6 and stored in the storage unit 61 of FIG. Actually, the image information 67 is generated for each original image, and information indicating the type of each information element (that is, whether the information element is for OCR or the type of code pattern) is also included in the image information 67. It is.

  The original image data generated by the computer 5 in FIG. 1 is also output to the main body control unit 4, and continuously moves the printing paper 9 in the (−Y) direction from the heads 211 of the respective colors according to the original image data. By performing the ink ejection control, a print image is formed on the print paper 9 (that is, the original image is printed) (step S12). Then, the print images immediately after being formed are picked up by the plurality of image pickup units 71 positioned in the forward direction of the printing paper 9, and a plurality of picked-up images are acquired and output to the inspection unit 6 (step S13).

  For example, as shown in FIG. 4, when a part of the information element 73 in the print image on the print paper 9 overlaps the overlapping imaging region A2, FIG. A and FIG. As shown in B, an information element (the same reference numeral 73 as the information element on the printing paper 9) appears in each of the two captured images 81a and 81b. Actually, since the information element 73 partially overlaps each of the two imaging areas A1 sharing the overlapping imaging area A2 shown in FIG. 4, only a part of the information element 73 is included in each of the captured images 81a and 81b. appear. A plurality of captured image data (reference numeral 81 in FIG. 5) is stored in the storage unit 61.

  When a plurality of captured images are acquired, the region cutout unit 62 pays attention to each information element 73 indicated by the region data 672 of the image information 67, and includes the entire portion of the information element 73 of each captured image. The region is cut out and a partial region image is acquired (step S14). FIG. A and FIG. In the captured images 81a and 81b of B, FIG. A and FIG. Two partial area images 82a and 82b respectively shown in B are acquired.

  Here, in the printing system 1 of FIG. 1, the sheet-like printing paper 9 is continuously moved in the moving direction by the paper feeding mechanism 3, and a print image with ink is captured. In some cases, the printing paper 9 may be stretched or fluttered below the imaging unit 71. In this case, the position of the print image on the print paper 9 and the range of each imaging area A1 on the print paper 9 vary.

  Therefore, in a preferable method of acquiring a partial region image in consideration of flapping of the printing paper 9, first, a reference image that shows the same resolution and approximately the same region as each captured image using the original image data 671 of the image information 67. Is generated. At this time, the range of the information element in the reference image is also acquired by referring to the area data 672.

  Subsequently, the reference image and the captured image are aligned by obtaining the position of the predetermined reference mark included in the reference image and the position of the reference mark in the captured image. Then, a region in the captured image corresponding to a range obtained by expanding the range (region) of the information element in the reference image by a predetermined margin amount in the row direction and the column direction is specified as a partial region including the information element, and the captured image The partial area is cut out from the partial area image. The alignment between the reference image and the captured image is, for example, the pixel value of the captured image and the reference image at each of a plurality of positions when the captured image is swung in the row direction and the column direction with respect to the reference image. The sum of absolute values of differences from the corresponding pixel values may be obtained as an evaluation value, and the position where the evaluation value is minimized may be specified.

  Further, in the area cutout unit 62, when a plurality of partial area images are acquired for each information element, a plurality of partial area images each partially indicating the same information element are acquired. Determined. Here, the information element 73 on the printing paper 9 in FIG. 4 straddles the overlapping imaging area A2, and a plurality of partial area images 82a and 82b each partially showing the same information element 73 are acquired ( Step S15). In practice, even when a plurality of partial area images are acquired, the entire information element 73 may be included in one partial area image. A plurality of partial area images partially showing the same information element are treated as acquired.

  Subsequently, the barcode determination unit 63 refers to the image information 67 to identify the type of the information element 73, whereby the information element 73 in the print image is a barcode in which a plurality of bars are arranged in the moving direction (see FIG. 13 (hereinafter referred to as “ladder barcode”) (step S16), and then the image compositing unit 64 includes two parts each partially representing the same information element. By combining the two partial area images 82a and 82b while overlapping the overlapping parts in the partial area images 82a and 82b, one information element image 83 showing the entire information element 73 is generated as shown in FIG. (Step S17).

  Here, as described above, in the printing system 1, the printing paper 9 that is moving may flutter, and in this case, the length in the width direction of the overlapping imaging region A2 varies (that is, the overlapping imaging region). The length in the X direction of the area on the printing surface of the printing paper 9 included in A2 dynamically changes). Specifically, in a state where the printing paper 9 below the imaging unit 71 (having a non-telecentric optical system) is lifted from the belt 32, the imaging range R1 in the width direction of each imaging unit 71 is the printing paper. 9 is narrower than the normal state in which it does not float, and the length in the width direction of the overlapping imaging region A2 in the two adjacent imaging regions A1 is also reduced. In this case, the length in the row direction of the overlapping portion in the two partial region images 82a and 82b changes compared to the normal state.

  Therefore, the image composition unit 64 performs composition based on features such as pixel values of the actual partial region image. Specifically, the width (number of pixels) corresponding to the length in the width direction of the overlapping imaging region A2 in the normal state is set in the row direction (the left-right direction in FIGS. 11.A and 11.B) in FIG. FIG. 11 shows a right end portion of the partial area image 82a of FIG. B is overlapped with the left end of the partial area image 82b, and the lower edges of the two partial area images 82a and 82b are overlapped in the column direction (vertical direction in FIGS. 11.A and 11.B). The pixel value of one partial area image and the other at each of a plurality of positions when the position of one partial area image is swung in the row direction and the column direction with respect to the other partial area image from the reference position The sum of absolute values of differences from corresponding pixel values of the partial area image is obtained as an evaluation value.

  At this time, in the printing system 1, the fluctuation width of the length in the width direction of the overlapping imaging area A2 (that is, the maximum contraction length) is the length in the width direction of the overlapping imaging area A2 on the printing paper 9 in a normal state where the overlapping imaging area A2 does not float. The search range in the row direction is the range of the overlapping imaging region A2, which is obtained in advance by experiments or the like with the reference as the reference, and the search range is a range in which the position of one partial region image is shaken in each direction with the reference position as a reference. The width is set to a width (preferably a width equal to or less than twice the fluctuation width) equal to or larger than the fluctuation width in the width direction. Further, the search range in the column direction is set to a predetermined width equal to or less than the length in the column direction of the partial region image (for example, a margin amount in the column direction when the partial region is cut out). Then, the two partial area images 82a and 82b are synthesized at the position where the evaluation value is minimum, and the information element image 83 is generated. The difference in the position in the column direction of the information element 73 in the two partial area images 82a and 82b (for example, the position from the lower edge) is obtained when the partial area image is acquired from the captured image in step S14. This is because the partial area search is performed individually for each information element of the captured image.

  Subsequently, in the decoding unit 651 of the information comparison unit 65 in FIG. 5, character information or numerical information is read as acquired information from the information element 73 of the information element image 83 in FIG. 12 by OCR. When the information element is a code pattern, the information obtained by decoding the information element indicated by the information element image using the decode parameter 681 (decode parameter corresponding to the type of the code pattern) stored in the storage unit 61 is acquired. Is read. Then, the acquired information and the original information 673 are compared, and if both match completely, a result indicating normality is output, and if they do not completely match, a result indicating abnormality (bad) is output. The result data 682 is stored in the storage unit 61 (step S18).

  On the other hand, as shown in FIG. 13, when the ladder barcode straddling the overlapping imaging area A2 is the information element 73a, FIG. A and FIG. As shown in B, two partial region images 82c and 82d each partially showing the same information element 73a are acquired (steps S14 and S15). The barcode determination unit 63 confirms that the information element 73a is a ladder barcode by referring to the image information 67 (step S16), and the image selection unit 631 determines the two partial area images 82c and 82d. Among these, the partial region image 82c having the maximum width in the row direction is identified and output to the information comparison unit 65 as an information element image (step S19). And the acquisition information calculated | required from an information element image and original information are compared, and test result data 682 are acquired (step S18).

  The image selection unit 631 refers to the region data 672 of the image information 67, and selects the portion indicating the ladder barcode that has the maximum width in the row direction. It may be specified. If the information element is a barcode (also referred to as picket) in which a plurality of bars are arranged in the width direction, the image composition unit 64 performs a process of compositing a plurality of partial area images.

  When only one partial region image is acquired for the information element in the process of step S15, the partial region image indicating the entire information element is output to the information comparison unit 65 as the information element image. The acquired information obtained from the information element image is compared with the original information (step S18).

  In the printing system 1 of FIG. 1, a printing apparatus 11 (a head unit 2 that is a component related to dot drawing) and a plurality of imaging units 71 that form a print image are arranged along the movement path of the printing paper 9. In the actual printing operation in the printing system 1, a large number of print images are continuously formed on the printing paper 9 by the printing apparatus 11 based on a large number of original images each including information elements each representing different original information. At the same time, an information element in each print image is inspected immediately after formation by an inspection apparatus having a plurality of imaging units 71, a paper feed mechanism 3, and an inspection unit 6. The inspection unit 6 also inspects portions other than the information elements of the print image by comparing each captured image with the corresponding reference image, thereby detecting missing dots in the print image.

  By the way, assuming a printing system of a comparative example in which only one image pickup unit is provided, when the entire print image on the printing paper is picked up by the print system, the resolution of the picked-up image becomes low and thin lines and Information elements including many parts close to each other cannot be accurately inspected. In addition, by setting the imaging area of the imaging unit for each page in the printing system of the comparative example, it may be possible to capture only the area including the information element in the printed image with high resolution. When there are a plurality of information elements, or when a captured image is used for inspection of a portion other than the information element of the print image, the inspection cannot be performed efficiently. Furthermore, when using a plurality of imaging units, a plurality of captured images each partially showing the same information element may be acquired (that is, the information elements appear in a plurality of images). In some cases, it is conceivable to combine a plurality of captured images to generate an image showing the entire information element. However, since the captured image is usually a large size, the compositing process takes a long time.

  On the other hand, in the printing system 1, a plurality of imaging units 71 that respectively capture a plurality of imaging regions A1 that partially overlap on the printing paper 9 are provided, and a plurality of high-resolution captured images are acquired. A partial region including at least a part of the information element is cut out from the captured image. When a plurality of partial area images each partially representing an information element are acquired, an information element image obtained by combining the plurality of partial area images is generated, and the acquired information from the information element image is the original information. To be compared. As described above, in the printing system 1, even when a plurality of captured images each partially showing the same information element are acquired, an image showing the entire information element can be efficiently generated. It becomes possible to inspect easily and in a short time.

  In the printing system 1, when the information element is a ladder barcode and the region cutout unit 62 acquires a plurality of partial area images each partially showing the same ladder barcode, The code determination unit 63 outputs the partial region image having the maximum width in the row direction or the partial region image having the maximum width in the row direction of the portion indicating the ladder barcode to the information comparison unit 65 as an information element image. The Thereby, the process which synthesize | combines a some partial area image is abbreviate | omitted, and the information element which is a ladder barcode can be test | inspected for a shorter time.

  Furthermore, when the length in the width direction of the overlapping imaging region A2 varies due to flapping of the printing paper 9 on the way of movement, the image composition unit 64 has a search range for overlapping overlapping portions in a plurality of partial region images. The width is set to be equal to or larger than the fluctuation width in the width direction of the overlapping imaging region A2. As a result, even when the printing paper 9 on the way is fluttering, an information element image can be generated with high accuracy, and a highly accurate information element inspection can be realized.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  In the above embodiment, the partial area image is acquired in consideration of deformation of the printing paper 9 or the like. However, in the printing system 1, when a printing medium having high rigidity against deformation is used, the area data of the image information 67 is used. The partial region image may be acquired by cutting out a region corresponding to the region of the information element indicated by 672 from the captured image. Also, two partial area images each partially showing the same information element are combined, and the end of one partial area image and the end of the other partial area image correspond to the overlapping imaging area A2 in the normal state. It is also possible to perform by overlapping in the row direction by the width (number of pixels) to be performed.

  A plurality of imaging units 71 are connected to a plurality of computers, respectively, and each computer acquires partial region images. Each of the plurality of partial region images partially showing the same information element is displayed on one computer (one A computer connected to the imaging unit 71 or another computer) may generate the information element image by combining the partial area images, and the information element indicated by the information element image may be inspected.

  In the printing system, for example, a plurality of imaging units may be arranged in two directions above one print medium placed on a stage. Also in this case, a plurality of imaging regions of a plurality of imaging units on the print medium are partially overlapped, and each of the plurality of (may be three or more) parts partially showing the same information element. When a region image is acquired, an information element image indicating the entire information element is generated by combining the plurality of partial region images while overlapping the overlapping portions in the plurality of partial region images.

  The synthesis of the two partial area images is performed by, for example, a plurality of characteristic parts (for example, the partial area images 82a and 82b shown in FIGS. 11A and 11B in the portion of the information element included in the overlapping imaging area A2. In the information element 73 in “C”, the positions of the four corner portions (shown by circles with a symbol F) are extracted, and two partial region images are arranged so that these portions overlap each other. The region image may be synthesized. As described above, when the partial region images are synthesized using the features of the parts included in the overlapping imaging region A2, the resolutions of the plurality of captured images acquired by the plurality of imaging units 71 are slightly different. Even when the captured image is partially distorted, the partial area image can be appropriately synthesized.

  In FIG. 4, the information element 73 is composed of a plurality of characters, but the information element may be one character, number, or symbol. In the printing system 1, at least one character, number, symbol, or code is used. An information element that is a pattern is inspected.

  The printing system 1 may include a plateless printing apparatus (for example, an electrophotographic printing apparatus) other than the inkjet printing apparatus. In this case, the imaging unit 71, the paper feed mechanism 3, and the inspection unit are also included. With the inspection apparatus having 6, the information elements in the printed image can be easily inspected in a short time. Further, the inspection apparatus is not necessarily provided integrally with the printing apparatus, and the inspection apparatus may be provided independently of the printing apparatus.

  By the way, when a print image is formed on a print sheet by an ink jet printing apparatus, the print sheet easily expands and contracts, and the information element in the captured image is shifted from the position (design position) obtained from the area data. End up. Even in such a case, in this inspection apparatus, since a wide range (the whole in the above embodiment) on the printing paper 9 can be imaged by the plurality of imaging units 71, the information element can be appropriately inspected. . Therefore, it can be said that the present inspection apparatus is particularly suitable for inspecting information elements included in a printed image on a printing paper formed by an ink jet printing apparatus.

  The printing medium in the printing system 1 may be a film or a plate-like member in addition to the printing paper. For example, when a plate-like member that is divided into a plurality of cards in a later step is used as a print medium, an information element formed at a portion corresponding to each card is inspected. When various substrates are used as print media, a resist pattern formed on the substrate is also regarded as a print image, and information elements included in the resist pattern are inspected.

1 is a diagram illustrating a configuration of a printing system. It is a bottom view of a discharge part. It is a figure which shows arrangement | positioning of a some imaging part. It is a figure which shows the imaging area on printing paper. It is a block diagram which shows the function structure which concerns on the test | inspection of a printed image. It is a figure which shows an example of an information element. It is a figure which shows the other example of an information element. It is a figure which shows the further another example of an information element. It is a figure which shows the further another example of an information element. It is a figure which shows the further another example of an information element. It is a figure which shows the further another example of an information element. It is a figure which shows the further another example of an information element. It is a figure which shows the further another example of an information element. It is a figure which shows the flow of the operation | movement which prints an image on printing paper and test | inspects a printed image. It is a figure which shows a captured image. It is a figure which shows a captured image. It is a figure which shows a partial region image. It is a figure which shows a partial region image. It is a figure which shows an information element image. It is a figure which shows the information element on printing paper. It is a figure which shows a partial region image. It is a figure which shows a partial region image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Paper feed mechanism 6 Inspection unit 9 Printing paper 11 Printing apparatus 62 Area extraction part 63 Barcode determination part 64 Image composition part 65 Information comparison part 71 Imaging part 73, 73a Information element 81, 81a, 81b Captured image (data)
82a, 82b, 82c, 82d Partial area image 83 Information element image 671 Original image data 673 Original information A1 Imaging area A2 Overlapping imaging area

Claims (6)

An inspection device for inspecting an information element that is at least one character, number or symbol or code pattern included in a print image formed on a print medium according to original image data,
A plurality of imaging units that respectively capture a plurality of imaging regions that partially overlap on the print medium and acquire a plurality of captured images;
In the plurality of captured images, a region cutout unit that cuts out a partial region including at least a part of one information element and obtains at least one partial region image;
When a plurality of partial area images each partially representing the information element are acquired, the information is obtained by combining the plurality of partial area images while overlapping the overlapping parts in the plurality of partial area images. An image composition unit for generating an information element image showing the entire element;
An information comparison unit that compares original information that is character information or numerical information represented in the information element at the time of generation of the original image data and acquired information that is character information or numerical information acquired from the information element image; ,
An inspection apparatus comprising: The inspection apparatus according to claim 1,
A moving mechanism for continuously moving the printing medium in a moving direction parallel to the printing surface of the printing medium;
The plurality of imaging units are a plurality of line sensors arranged in a width direction parallel to the printing surface and perpendicular to the moving direction;
The plurality of imaging regions are a plurality of strip regions extending in the moving direction and arranged in the width direction, and two overlapping regions adjacent to each other in the width direction partially overlap with each other in the width direction. An inspection apparatus characterized by forming a region. The inspection apparatus according to claim 2,
The print medium is sheet-like, and the length in the width direction of the overlapping imaging region varies due to flapping of the print medium in the course of movement,
When the image synthesizing unit overlaps overlapping portions in the plurality of partial region images, a search range having a width equal to or greater than a variation width in the width direction of the overlapping imaging region is set with respect to a direction corresponding to the width direction. Inspection apparatus characterized by that. The inspection apparatus according to claim 2 or 3,
An inspection apparatus, wherein the printing apparatus that prints the print image and the plurality of imaging units are arranged along a movement path of the print medium. The inspection apparatus according to any one of claims 2 to 4,
When the information element is a barcode in which a plurality of bars are arranged in the moving direction, and the plurality of partial region images are acquired by the region cutout unit, the plurality of partial region images out of the plurality of partial region images The information having the maximum width in the direction corresponding to the width direction or the maximum width in the direction corresponding to the width direction of the portion indicating the barcode is output to the information comparison unit as the information element image. An inspection apparatus further comprising a bar code determination unit. The inspection apparatus according to any one of claims 1 to 5,
The printing medium is printing paper;
An inspection apparatus, wherein the print image is formed by an ink jet printing apparatus.

Images