Desensitization printing inspection method

Abstract

To allow an efficient and precise examination to find out whether desensitizing printing was performed correctly on a pressure-sensitive copy slip form.SOLUTION: Plural types of reference pressure-sensitive copy slip forms are prepared, are subjected to coloring processing so that the region other than the desensitizing ink application region produces light, and are imaged. After that, an examination window is set in the gray-scale image of each reference pressure-sensitive copy slip form, the image part of the examination window is used as a reference image part and is registered with the threshold value of the luminance that distinguishes the desensitizing ink application region and the other region in the reference image part. Subsequently, an examination target pressure-sensitive copy slip form is subjected to coloring processing and is imaged, an examination window common to the reference pressure-sensitive copy slip form for the gray-scale image of the examination target pressure-sensitive copy slip form is set, the image part in the examination window and its corresponding reference image part are binarized, the difference between corresponding desensitizing ink application regions is taken, and it is determined that desensitizing print was performed correctly on the inspection target pressure-sensitive copy slip form when the difference is within an acceptance range.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for inspecting whether desensitization printing of pressure-sensitive copy form paper is normally performed in the manufacturing process of pressure-sensitive copy forms.

Background Art

[0002] A pressure-sensitive copy form is composed of a plurality of form papers including at least one pressure-sensitive recording paper (hereinafter referred to as "pressure-sensitive copy form paper"). On the surface of each form paper, a form is printed in a predetermined format using ordinary printing ink.

[0003] Normally, the entire surface of the pressure-sensitive copy form paper is the copying range. Therefore, when there is an area in the pressure-sensitive copy form paper that does not require copying, desensitizing ink (transparent special ink) is printed on that area of the pressure-sensitive copy form paper (see, for example, Patent Documents 1 and 2).

[0004] This printing process is usually called "desensitization printing", and a desensitization plate is used for desensitization printing. Different desensitization plates are prepared for each type of pressure-sensitive copy form paper. Then, desensitization printing is performed using a desensitization plate corresponding to the type of pressure-sensitive copy form paper.

[0005] By the way, when a desensitization plate that does not correspond to the type of pressure-sensitive copy form paper is used, desensitization printing is performed at the wrong position on the pressure-sensitive copy form paper. In this case, characters and numbers entered in the area where copying is not required are copied, and characters and numbers entered in the area where copying is required are not copied, and the function of the form is not exerted at all.

[0006] Also, even when the combination of the pressure-sensitive copy form paper and the desensitization plate is correct, if printing unevenness or misalignment occurs, the desensitizing ink will overflow to the area where copying is required, or will be applied only to a part of the area where copying is not required, and the function of the form will not be correctly exerted.

[0007] Therefore, in the manufacturing process of pressure-sensitive carbonless forms, it is inspected whether desensitizing printing has been performed normally. Conventionally, in this inspection, first, pressure-sensitive carbonless form paper that has been accurately desensitized by desensitizing printing is color-developed with a desensitizing ink checker, and a paper with the area other than the desensitizing ink application area of the pressure-sensitive carbonless form paper colored blue is prepared in advance as a reference form paper and stored for each type of pressure-sensitive carbonless form paper.

[0008] Then, the test pressure-sensitive carbonless form paper manufactured by performing desensitizing printing using a combination of the pressure-sensitive carbonless form paper to be inspected and a desensitizing plate is similarly color-developed with a desensitizing ink checker, and the test pressure-sensitive carbonless form paper after the color-developing process is visually compared and contrasted with the reference form paper of the same type by an operator. If the positions, shapes, and sizes of the desensitizing ink application areas match within a predetermined allowable range between the two, it is determined that the desensitizing printing has been performed normally.

[0009] However, such visual inspection by an operator is inefficient, and there is a problem that inspection errors are likely to occur due to the operator's carelessness.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, an object of the present invention is to provide a method capable of accurately and efficiently inspecting whether desensitizing printing of pressure-sensitive carbonless form paper has been performed normally.

Means for Solving the Problems

[0012] In order to solve the above problems, according to the present invention, (1) a plurality of types of pressure-sensitive copy ticket papers each pre-attached with a ticket paper type code, and a plurality of types of desensitized plates are prepared; (2) the pressure-sensitive copy ticket paper accurately desensitized using the correct desensitized plate is used as a reference pressure-sensitive copy ticket paper, the ticket paper type code of the reference pressure-sensitive copy ticket paper is read, and the reference pressure-sensitive copy ticket paper is subjected to a color development process to cause areas other than the desensitized ink application areas in the reference pressure-sensitive copy ticket paper to develop color; (3) the color-developed reference pressure-sensitive copy ticket paper is photographed by a camera; (4) in the grayscale image of the reference pressure-sensitive copy ticket paper, the shape of one characteristic part of the reference pressure-sensitive copy ticket paper is registered in association with the ticket paper type code, an X-Y coordinate system is set in the grayscale image, the center of the characteristic part is made to coincide with the origin of the X-Y coordinate system, and the main axis of the characteristic part is made to coincide with one coordinate axis of the X-Y coordinate system; (5) at least one rectangular inspection window including at least one of the desensitized ink application areas is set in the grayscale image of the reference pressure-sensitive copy ticket paper, and the position, height, and width of the inspection window are registered in association with the ticket paper type code as inspection window data; (6) for each inspection window in the grayscale image of the reference pressure-sensitive copy ticket paper, a luminance threshold value capable of distinguishing the desensitized ink application area in the inspection window from other areas is set, the threshold value is registered in association with the inspection window, and the image part in the inspection window is registered in association with the inspection window as a reference image part; (7) the ticket type code of the test pressure-sensitive copy ticket paper manufactured by performing desensitized printing using the combination of the pressure-sensitive copy ticket paper to be inspected and the desensitized plate is read, and the test pressure-sensitive copy ticket paper is subjected to the color development process to cause areas other than the desensitized ink application areas in the test pressure-sensitive copy ticket paper to develop color; (8) the color-developed test pressure-sensitive copy ticket paper is photographed by the camera; (9) based on the shape of the characteristic part corresponding to the ticket paper type code among the registered shapes of the characteristic parts, the characteristic part in the grayscale image of the test pressure-sensitive copy ticket paper is detected, an X-Y coordinate system is set in the grayscale image, the center of the detected characteristic part is made to coincide with the origin of the X-Y coordinate system, andAlign the major axis of the detected feature portion with one of the coordinate axes of the X-Y coordinate system, and (10) in the grayscale image of the pressure-sensitive copy form paper to be inspected, set the inspection window based on the inspection window data corresponding to the form paper type code among the registered inspection window data. For each inspection window, based on the threshold value corresponding to the form paper type code among the registered threshold values, binarize the image portion within the inspection window and the reference image portion corresponding to the form paper type code among the registered reference image portions, respectively. Take the difference between the desensitized ink application area within the inspection window and the corresponding desensitized ink application area in the reference image portion. When the difference is within a preset allowable range, it is determined that the desensitized printing of the pressure-sensitive copy form paper to be inspected has been performed normally. A desensitized printing inspection method is provided.

[0013] According to a preferred embodiment of the present invention, in step (10), after setting the inspection window and before binarizing the image portion within the inspection window and the corresponding reference image portion for each inspection window, perform pattern matching between the corresponding reference image portion and the image portion within the inspection window to correct the deviation of the position of the image portion within the inspection window so that the image portion within the inspection window most closely matches the corresponding reference image portion.

[0014] According to another preferred embodiment of the present invention, the feature portion consists of a certain number of digits of a form inquiry number printed in advance in a predetermined desensitized ink application area of the pressure-sensitive copy form paper. The center of the feature portion is the center of a rectangular block defined by the character string of the form inquiry number when the form inquiry number is read by OCR. The major axis of the feature portion is a central axis passing through the center of the rectangular block and extending parallel to the long side of the rectangular block.

Advantages of the Invention

[0015] According to the present invention, a plurality of types of reference pressure-sensitive copy form papers are prepared. After each reference pressure-sensitive copy form paper is subjected to a coloring process to color the areas other than the desensitized ink application areas, it is photographed with a camera. An inspection window is set in the grayscale image of each reference pressure-sensitive copy form paper, and the image portion within the inspection window is registered as a reference image portion together with the luminance threshold value for distinguishing the desensitized ink application area and the other areas in the reference image portion.

[0016] Then, after the test pressure-sensitive copy form paper is subjected to a coloring process, it is photographed with a camera. An inspection window common to the corresponding reference pressure-sensitive copy form paper is set in the grayscale image of the test pressure-sensitive copy form paper. The image portion within the inspection window and the corresponding reference image portion are each binarized, and the difference between the corresponding desensitized ink application areas is taken. When the difference is within a preset allowable range, it is determined that the desensitized printing of the test pressure-sensitive copy form paper has been performed normally.

[0017] Thus, according to the present invention, without relying on the visual inspection of an operator, the images of the test pressure-sensitive copy form paper and the reference pressure-sensitive copy form paper photographed with a camera are image-processed, and the inspection is performed by taking the difference between the corresponding desensitized ink application areas in the two images, so that an accurate and efficient inspection can be performed.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Best Mode for Carrying Out the Invention

[0019] Hereinafter, with reference to the accompanying drawings, the configuration of the present invention will be described based on preferred embodiments. FIG. 1 is a flowchart of a desensitization printing inspection method according to an embodiment of the present invention.

[0020] Referring to FIG. 1, according to the present invention, first, a plurality of types of pressure-sensitive copy invoice papers each pre-attached with an invoice paper type code and a plurality of types of desensitization plates are prepared (S1 in FIG. 1).

[0021] In this embodiment, the invoice paper type code is printed in the form of a character string on the margin portion outside the invoice printing surface of the pressure-sensitive copy invoice paper, but it may be represented by a barcode instead of the character string.

[0022] Also, in this embodiment, the entire paper surface of the pressure-sensitive copy invoice paper is the copying range. And when there is an area in the pressure-sensitive copy invoice paper that does not require copying, desensitization printing is performed on the area of the pressure-sensitive copy invoice paper using a desensitization plate and desensitization ink.

[0023] According to the present invention, next, the pressure-sensitive copy invoice paper that has been accurately desensitization printed (without causing unevenness or misalignment in printing) using the correct desensitization plate is used as a reference pressure-sensitive copy invoice paper, the invoice paper type code of the reference pressure-sensitive copy invoice paper is read, and the reference pressure-sensitive copy invoice paper is subjected to a color development process to cause the areas other than the desensitization ink application areas in the reference pressure-sensitive copy invoice paper to develop color (S2 in FIG. 1).

[0024] In this embodiment, the invoice paper type code of the reference pressure-sensitive copy invoice paper is read visually, but when the invoice paper type code is represented by a barcode, it is read by a barcode reader.

[0025] The color development process is performed by applying a desensitizing ink checker to the reference pressure-sensitive copy form paper. By the color development process, areas other than the desensitizing ink application area in the reference pressure-sensitive copy form paper turn blue, but the desensitizing ink application area does not develop color (remains white).

[0026] According to the present invention, next, the color-developed reference pressure-sensitive copy form paper is photographed by a camera (S3 in FIG. 1). As the camera, either a color camera or a monochrome camera may be used. In this embodiment, at the time of photographing, a form paper mounting table equipped with means for positioning the pressure-sensitive copy form paper in a fixed position is prepared, a camera is provided at a fixed position above the mounting table, and an appropriate lighting device for uniformly irradiating light on the surface of the pressure-sensitive copy form paper is provided, so that the positional relationship between the pressure-sensitive copy form paper to be photographed and the camera is always kept constant, and a clear image as much as possible can be obtained.

[0027] According to the present invention, further, in the grayscale image (bitmap image) of the obtained reference pressure-sensitive copy form paper, the shape of one characteristic part of the reference pressure-sensitive copy form paper is associated with the form paper type code and registered, and an X-Y coordinate system is set in this grayscale image, the center of the characteristic part is made to coincide with the origin of the X-Y coordinate system, and the main axis of the characteristic part is made to coincide with one coordinate axis of the X-Y coordinates (S4 in FIG. 1).

[0028] In this case, when a color camera is used for photographing, the obtained color image is converted into a grayscale image. FIG. 2 shows a display screen displaying the grayscale image of the reference pressure-sensitive copy form paper. In FIG. 2, the portion drawn with oblique lines indicates the area 1 that has developed color by the color development process, and the white portions indicate the desensitizing ink application areas 2 to 5.

[0029] Referring to FIG. 2, in this embodiment, the characteristic portion consists of a slip inquiry number (identification number of the pressure-sensitive copy slip paper) 6 of a certain number of digits (12 digits in this embodiment) printed in advance in a predetermined column (desensitized ink application area 2) of the pressure-sensitive copy slip paper. Then, the detection of the characteristic portion (slip inquiry number 6) is performed by OCR (optical character recognition). As shown in FIGS. 3(A) and 3(B), when reading by this OCR, the shape (rectangle) of the rectangular block 7 defined by the character string of the slip inquiry number 6 becomes the shape of the characteristic portion. The center C of this rectangular block 7 is the center of the characteristic portion, and the main axis of the characteristic portion is the central axis M that passes through the center C of the rectangular block 7 and extends parallel to the long side of the rectangular block 7.

[0030] Furthermore, in this embodiment, the X-Y coordinate system is set such that the upper left corner of the screen when the grayscale image of the reference pressure-sensitive copy slip paper is displayed on the display is the coordinate origin, and the horizontal and vertical directions of the screen are the X-axis and Y-axis, respectively. Then, as shown in FIG. 3(B), the main axis M of the rectangular block 7 is made to coincide with the X-axis of the X-Y coordinate system.

[0031] Note that the characteristic portion is not limited to this embodiment, and an appropriate image portion unique to the pressure-sensitive copy slip paper that can be an alignment mark in the grayscale image of the pressure-sensitive copy slip paper subjected to color development processing can be used as the characteristic portion.

[0032] According to the present invention, further, as shown in FIG. 4, at least one rectangular inspection window 8 to 10 including at least one desensitized ink application area 2 to 5 is set in the grayscale image of the reference pressure-sensitive copy slip paper, and the positions (positions of at least one point among the four corners and the center of the inspection windows 8 to 10), height, and width of the inspection windows 8 to 10 are associated with the slip paper type code as inspection window data and registered (S5 in FIG. 1).

[0033] In this case, a plurality of inspection windows may partially overlap, or another inspection window may be located within the range of one inspection window. Also, one desensitized ink application area may be included in a plurality of inspection windows.

[0034] Next, for each of inspection windows 8 to 10 in the grayscale image of the pressure-sensitive copying form for reference, a luminance threshold value is set that can distinguish the desensitized ink application areas 2 to 5 within the inspection window from the other areas (colored areas) 1, and the threshold value is registered in relation to inspection windows 8 to 10. At the same time, the image portions within inspection windows 8 to 10 are registered in relation to inspection windows 8 to 10 as reference image portions 11 to 13 (S6 in FIG. 1).

[0035] According to the present invention, further, when there are strings, figures, etc. printed in advance within the desensitized ink application areas 2 to 5, a rectangular area surrounding those strings, figures, etc. is set as an inspection exclusion area, and its position, height, and width are registered. In this embodiment, since the form inquiry number 6 exists within the desensitized ink application area 2, as shown in FIG. 3(C), the area surrounding the form inquiry number 6 in a rectangular shape is set as the inspection exclusion area 14, and its position (the position of at least one point among the four corners and the center of the inspection exclusion area 14), height, and width are registered.

[0036] The reason for registering the inspection exclusion area is to remove noise portions (portions detected as areas other than the desensitized ink application area) that occur within the desensitized ink application area when distinguishing the desensitized ink application area and other areas in the image by binarization of the image in a subsequent process (described later).

[0037] According to the present invention, thereafter, the form type code of the pressure-sensitive copying form to be inspected, which is manufactured by performing desensitized printing using a combination of the pressure-sensitive copying form to be inspected and a desensitized plate, is read, and the pressure-sensitive copying form to be inspected is color-developed in the same manner as before to cause the areas other than the desensitized ink application area in the pressure-sensitive copying form to be inspected to be color-developed (S7 in FIG. 1).

[0038] According to the present invention, further, the color-developed test pressure-sensitive copy ticket paper is photographed by a camera (S8 in FIG. 1), and based on the shape of the feature portion corresponding to the ticket paper type code among the registered feature portion shapes, the feature portion in the grayscale image of the test pressure-sensitive copy ticket paper is detected. An X-Y coordinate system is set in the grayscale image, and the center of the detected feature portion is made to coincide with the origin of the X-Y coordinate system, and the major axis of the detected feature portion is made to coincide with the X-axis of the X-Y coordinate system (S9 in FIG. 1).

[0039] In this embodiment, similar to the case of the reference pressure-sensitive copy ticket paper, the ticket inquiry number in the grayscale image of the test pressure-sensitive copy ticket paper is read by OCR, and the rectangular block related to the ticket inquiry number is detected.

[0040] Also, in this embodiment, similar to the case of the reference pressure-sensitive copy ticket paper, the X-Y coordinate system is set such that the upper left corner of the screen when the grayscale image of the test pressure-sensitive copy ticket paper is displayed on the display is the coordinate origin, and the horizontal and vertical directions of the screen are the X-axis and Y-axis, respectively. Then, the center of the detected rectangular block is made to coincide with the origin of the X-Y coordinate system, and the major axis of the detected rectangular block is made to coincide with the X-axis of the X-Y coordinate system.

[0041] Next, an inspection window is set in the grayscale image of the test pressure-sensitive copy ticket paper based on the inspection window data corresponding to the ticket paper type code among the registered inspection window data. For each inspection window, based on the threshold value corresponding to the ticket paper type code among the registered threshold values, the image portion in the inspection window and the reference image portion corresponding to the ticket paper type code among the registered reference image portions are each binarized, and the difference between the desensitized ink application area in the inspection window and the corresponding desensitized ink application area in the reference image portion is taken. When the difference is within a preset allowable range, it is determined that the desensitized printing of the test pressure-sensitive copy ticket has been performed normally (S10 in FIG. 1).

[0042] In this case, after binarizing each of the image portion within the inspection window and the corresponding reference image portion, before taking the difference between the desensitized ink application area within the inspection window and the corresponding desensitized ink application area in the reference image portion, if necessary, for each of the binarized image portion within the inspection window and the binarized reference image portion, in order to remove noise and improve inspection accuracy, closing processing is performed after opening processing, and when the inspection exclusion area 14 is set, processing for removing the area from the image is performed.

[0043] Also, after setting the inspection window and before binarizing the image portion within the inspection window and the corresponding reference image portion for each inspection window, if necessary, pattern matching between the reference image portion and the image portion within the inspection window (in this embodiment, correlation-based matching (normalized cross-correlation model) is adopted) is performed to correct the displacement of the position of the image portion within the inspection window so that the image portion within the inspection window most closely matches the reference image portion.

[0044] As a result, even when the inspected pressure-sensitive copy form paper is photographed by a camera in a bent or distorted state, and only the alignment of the grayscale images of the inspected pressure-sensitive copy form paper and the reference pressure-sensitive copy form paper based on the characteristic portions is performed, and the accuracy of the difference taken between the desensitized ink application area within the inspection window and the corresponding desensitized ink application area in the reference image portion is not sufficient, it becomes possible to take the difference extremely accurately.

[0045] Also, the allowable range of the difference is represented by, for example, a numerical range in units of 0.1 mm as to how far within or outside the distance range on the inner and outer sides of the edge portion of the corresponding desensitized ink application area in the reference image portion the edge portion of the desensitized ink application area within the inspection window should be in order to have no practical problem.

[0046] Thus, according to the present invention, without depending on the visual inspection of an operator, the images of the inspected pressure-sensitive copy form paper and the reference pressure-sensitive copy form paper photographed by a camera are image-processed, and the inspection is performed by taking the difference between the mutually corresponding desensitized ink application areas in the two images, so that an accurate and efficient inspection can be performed.

Explanation of Signs

[0047] 1 Region colored by color development processing 2 - 5 Desensitized ink application regions 6 Slip inquiry number (identification number for pressure-sensitive copy slip paper) 7 Rectangular block 8 - 10 Inspection windows 11 - 13 Reference image portions 14 Inspection exclusion region C Center M Major axis

Claims

1. (1)Prepare a plurality of types of pressure-sensitive carbonless paper, each with a pre-assigned form paper type code, and a plurality of types of desensitized plates. (2)Use the correct desensitized plate to accurately perform desensitized printing on the pressure-sensitive carbonless paper to obtain a reference pressure-sensitive carbonless paper. Read the form paper type code of the reference pressure-sensitive carbonless paper, and perform a color development process on the reference pressure-sensitive carbonless paper to cause areas other than the desensitized ink application areas in the reference pressure-sensitive carbonless paper to develop color. (3)Take a photograph of the color-developed reference pressure-sensitive carbonless paper using a camera. (4)In the grayscale image of the reference pressure-sensitive carbonless paper, register the shape of one characteristic part of the reference pressure-sensitive carbonless paper in relation to the form paper type code. Set an X-Y coordinate system within the grayscale image, align the center of the characteristic part with the origin of the X-Y coordinate system, and align the main axis of the characteristic part with one of the coordinate axes of the X-Y coordinate system. (5)Set a plurality of rectangular inspection windows in the grayscale image of the reference pressure-sensitive carbonless paper, each of which includes at least one desensitized ink application area. Register the positions, heights, and widths of the plurality of inspection windows as inspection window data in relation to the form paper type code. (6)For each inspection window in the grayscale image of the reference pressure-sensitive carbonless paper, set a luminance threshold value that can distinguish the desensitized ink application area within the inspection window from other areas, register the threshold value in relation to the inspection window, and register the image part within the inspection window as a reference image part in relation to the inspection window. (7)Read the form paper type code of the test pressure-sensitive carbonless paper manufactured by performing desensitized printing using the combination of the pressure-sensitive carbonless paper to be inspected and the desensitized plate. Perform the color development process on the test pressure-sensitive carbonless paper to cause areas other than the desensitized ink application areas in the test pressure-sensitive carbonless paper to develop color. (8)Take a photograph of the color-developed test pressure-sensitive carbonless paper using the camera. (9) Based on the shape of the registered characteristic part corresponding to the slip paper type code among the shapes of the registered characteristic parts, detect the characteristic part in the grayscale image of the test pressure-sensitive copy slip paper, set an X-Y coordinate system in the grayscale image, align the center of the detected characteristic part with the origin of the X-Y coordinate system, and align the major axis of the detected characteristic part with one of the coordinate axes of the X-Y coordinate system. (10) In the grayscale image of the test pressure-sensitive copy slip paper, set a plurality of inspection windows based on the inspection window data corresponding to the slip paper type code among the registered inspection window data. For each inspection window, based on the threshold value corresponding to the slip paper type code among the registered threshold values, binarize the image part within the inspection window and the reference image part corresponding to the slip paper type code among the registered reference image parts respectively. Take the difference between the desensitized ink application area within the inspection window and the corresponding desensitized ink application area in the reference image part. When the difference is within a preset allowable range, determine that the desensitized printing of the test pressure-sensitive copy slip paper has been performed normally. A desensitized printing inspection method characterized by this.

2. In step (10), after setting the inspection window and before binarizing the image part within the inspection window and the corresponding reference image part for each inspection window respectively, perform pattern matching between the corresponding reference image part and the image part within the inspection window to correct the misalignment of the position of the image part within the inspection window so that the image part within the inspection window most closely matches the corresponding reference image part. The desensitized printing inspection method according to claim 1, characterized by this.

3. The characteristic part consists of a fixed number of slip inquiry numbers printed in a predetermined desensitized ink application area of the pressure-sensitive copy slip paper in advance. The center of the characteristic part is the center of the rectangular block defined by the character string of the slip inquiry number when reading the slip inquiry number by OCR. The major axis of the characteristic part is the central axis passing through the center of the rectangular block and extending parallel to the long side of the rectangular block. The desensitized printing inspection method according to claim 1 or claim 2, characterized by this.

Images