Quality inspection method and quality inspection equipment for flat box bodies

Abstract

To provide a quality inspection method and a quality inspection equipment for flat box bodies that can reliably and accurately inspect the joining state of each box body, even if the box bodies of a laminate are misaligned back and forth, left and right, with respect to each other.SOLUTION: In this method of quality inspection of flat box bodies, on each side surface 9a, 9b of two side surfaces of a laminate 9 formed by stacking a plurality of box bodies 90, which are on the flap 90f side and open with a gap section 90g between flaps by joining, a region including at least a gap section row 9G in which gap sections 90g are arranged in the stacking direction is imaged obliquely from a position on the left / right side of the gap section row 9G, and the quality of joining is determined based on the image of the gap section row 9G on each side surface imaged.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a quality inspection method suitable for a box making machine that forms flat boxes. [Background technology]

[0002] A box-making machine is a device that produces boxes by printing on sheets, adding ruling lines and cutting grooves for flaps, gluing, folding and joining them. When folding a sheet and joining the ends to form a box, if the folding points are misaligned, the joints will also be misaligned. This misalignment is likely to occur with thick sheets, especially corrugated cardboard sheets, which can cause large misalignments at the joints, making it impossible to assemble three-dimensionally or resulting in a distorted shape.

[0003] Since such joints form gaps between the flaps, the gaps are imaged from above with a camera while the boxes are being transported, and the joints are inspected one by one based on the image. However, some box-making machines transport boxes in a stack of multiple boxes immediately after processing them into boxes, which can make it difficult to inspect the boxes one by one. In addition, since the boxes are shipped as a stack, there is a need to efficiently inspect the joints for misalignment while the boxes are in that stacked state.

[0004] A conventional method for inspecting the joints in this type of stack has been proposed, in which images of the front and back sides of the stack during transport are captured diagonally from above, and a row (gap row) of the gaps of each box body present on each side arranged in the stacking direction is captured, and the width of the gaps of each box body is calculated based on the captured image of the gap row, thereby inspecting the joint condition (see Patent Document 1).

[0005] However, the boxes of the stack to be imaged are misaligned from each other in the front-to-back and left-to-right directions due to vibrations during transportation, etc., and when the front and back sides are imaged from above, there is a problem that a box protruding in the front-to-back direction (protruding from the side to be imaged) hides the gap of the box below it, or a box that is recessed (shifted to the opposite side to the side to be imaged and forms a recess) is similarly hidden by the upper box, making it impossible to image the gap. To address this, it is possible to move the camera away from the stack in the front-to-back direction to reduce the shooting angle from above, but this would result in a problem of accuracy decreasing due to the camera being farther away and insufficient light, etc. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2001-330414 A Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above-mentioned situation, the present invention aims to solve the problem of providing a quality inspection method and quality inspection device for flat box bodies that can reliably and accurately inspect the joining condition of each box body even if the box bodies of the stack are misaligned relative to each other in the front-to-back or left-to-right directions. [Means for solving the problem]

[0008] That is, the present invention includes the following inventions. (1) A quality inspection method for a flat box body formed by folding and gluing a sheet material, the method comprising the steps of: imaging an area including at least a row of gaps arranged in the stacking direction on each of two sides of a stack formed by stacking a plurality of the box bodies, the area including at least a row of gaps arranged in the stacking direction on each of the two sides of the stack on the flap side where the gaps between the flaps formed by the joining are opened, obliquely from a position to the left or right of the row of gaps; and judging whether the joining is good or bad based on the image of the row of gaps on each of the sides.

[0009] (2) The quality inspection method according to (1), wherein the imaging is performed by imaging the area obliquely from a position within the same height range as the height of the laminate.

[0010] (3) A quality inspection method as described in (1) or (2), in which a line laser is irradiated onto the area diagonally from a position on the left / right side of the row of gaps so that an irradiation line extends in the stacking direction, and based on the state of the irradiation line displayed on the area by the irradiated line laser, the amount of misalignment in a direction perpendicular to each side of the overlap of each box body is calculated based on the calculated amount of misalignment and an image of the row of gaps, and the quality of the joint is judged based on the calculated amount of misalignment and an image of the row of gaps.

[0011] (4) A quality inspection method according to any one of (1) to (3), wherein, during the imaging, illumination is applied obliquely to the area from a position on the opposite side to the left / right of the imaging position.

[0012] (5) A quality inspection method described in any one of (1) to (4), in which the stack is transported in a direction perpendicular to each of the side surfaces, and the imaging is performed by imaging the front side and the rear side of the stack in the transport direction at an angle from positions on the left / right side along the transport path of the stack.

[0013] (6) A quality inspection device for a flat box formed by folding and gluing a sheet material, comprising: an imaging means for imaging an area including at least a row of gap portions arranged in the stacking direction on each of two sides of a stack formed by stacking a plurality of the box bodies, the row of gap portions being arranged in the stacking direction, the area including the row of gap portions being arranged in the stacking direction, from a position on the left / right side of the row of gap portions; A quality inspection device comprising: an illumination means for illuminating the area obliquely from positions on the left / right side of the gap row; and a judgment means for judging the quality of the joint based on images of the gap row on each side captured by the imaging means.

[0014] (7) A quality inspection device as described in (6), comprising: a laser irradiation means for irradiating the area with a line laser diagonally from a position on the left / right side of the gap column so that an irradiation line extends in the stacking direction; and a deviation calculation means for calculating an amount of deviation in a direction perpendicular to each side of the overlap of each box body based on a state of the irradiation line displayed on the area by the line laser irradiated by the laser irradiation means, wherein the judgment means judges the quality of the joining based on the amount of deviation calculated by the deviation calculation means and an image of the gap column. Effect of the Invention

[0015] According to the present invention, even if the boxes in the stack are misaligned from one another in the front-rear or left-right directions, the joining state of each box can be inspected reliably and accurately. [Brief description of the drawings]

[0016] [Figure 1] 1 is a conceptual diagram for explaining a quality inspection method of the present invention. [Diagram 2] Also a plan view. [Diagram 3] FIG. 1 is a conceptual diagram showing a configuration of a quality inspection device of the present invention. [Figure 4] FIG. 4 is an explanatory diagram showing a specific example of an imaging unit. [Diagram 5] FIG. 4 is an explanatory diagram showing a specific structure of the lighting means. [Figure 6] FIG. 11 is a conceptual diagram showing another example of the quality inspection device. [Figure 7] FIG. 4 is an explanatory diagram showing specific structures of an imaging unit and an illumination unit. [Figure 8] FIG. 2 is a block diagram showing the configuration of a control device. [Figure 9] 11 is a photograph showing an example of an image in which an irradiation line by a laser irradiation means is displayed. [Figure 10] 11 is a photograph showing an example of an image in which an example gap is displayed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0018] The present invention is a box quality inspection device suitable for use in a box-making machine that prints, folds, glues, and joins sheet materials to form flat boxes. In the following embodiments, an example will be described in which the sheet materials are cardboard sheets and a flat cardboard box is formed as the box body by the box-making machine, but the object of inspection in the present invention is not limited to cardboard boxes, and boxes made of various sheet materials can be inspected.

[0019] 1 and 2, the quality inspection method of the present invention involves taking images of two sides 9a, 9b of a stack 9 formed by stacking a plurality of box bodies 90, on which the flaps 90f of each box body 90 extend and on which the gaps 90g between the flaps 90f, 90f formed by joining the box bodies 90 are opened, of an area including at least a gap row 9G in which the gaps 90g are arranged in the stacking direction, from positions on the left and right sides of the gap row 9G, and judging the quality of the joining based on the images of the gap row 9G of each side 9a, 9b. In the drawings, reference numeral 2 denotes an imaging means for imaging the above-mentioned area, and reference numeral 3 denotes an illumination means for illuminating the above-mentioned area.

[0020] According to the method of imaging the above-mentioned region obliquely from the left / right side positions in this way, even if each box body 90 of the stack 9 is misaligned from each other in the front / back / left / right direction, the gap portion 90g is not hidden or shaded by the upper / lower box body 90, and there is no need to move the camera away, so the gap portion can be reliably and clearly imaged, and the bonding state of each box body can be reliably and accurately inspected. Although a pair of imaging means 2 and illumination means 3 is provided for each side surface 9a, 9b, the present invention also includes imaging or illuminating both side surfaces 9a, 9b with a single imaging means 2 and illumination means 3 by using a reflecting mirror or a moving mechanism (e.g., a rotating mechanism).

[0021] As shown in Fig. 3, the quality inspection device 1 of this embodiment is provided at an intermediate position along the conveyance path where flat boxes 90 are formed by a folder gluer, and then multiple boxes 90 are stacked one on top of the other to form a stack 9, which is then tied with string 8 or the like and conveyed. As long as the boxes are in the form of stack 9, the intermediate position may be one along the conveyance path before being tied with string 8 or the like. Furthermore, the present invention is not limited to being provided at an intermediate position along such conveyance (movement), and also includes one that is provided at a position where the boxes are temporarily stopped and an image of the stack in a stationary state is taken to inspect the stack.

[0022] The stack 9 is transported in a direction perpendicular to the front and rear sides 9a, 9b where the gap row 9G is open, and the imaging means 2 and illumination means 3 are disposed at positions on the left and right sides of the stack 9 along the transport path 10. The imaging means 2 specifically includes a first imaging means 21 that obliquely images the front side 9a in the transport direction of the stack 9 being transported, and a second imaging means 22 that obliquely images the rear side 9b of the stack 9 being transported. The imaging means 21, 22 can be, for example, area sensor cameras in which CCD imaging elements are arranged vertically and horizontally.

[0023] The first imaging means 21 and the second imaging means 22 are provided at approximately the same position in the conveying direction (the left side of the paper in FIG. 3), and are configured to capture images of the front side surface 9a and the rear side surface 9b of the stack 9 being conveyed from each position at an angle. Both are configured to capture images at an angle from a position within the same height range as the stack 9, but may also be provided at a position slightly higher than the stack 9.

[0024] Then, when the stack 9 is transported to a predetermined position P1 in front of that position, the first imaging means 21 images the area including the gap row 9G on the front side 9a of the stack 9, and when the stack 9 moves through transportation to a predetermined position P2 past the positions of the imaging means 21, 22, the second imaging means 22 images the area including the gap row 9G on the rear side 9b of the stack 9.

[0025] The predetermined positions P1, P2 of the stack 9 to be imaged can be easily realized by providing position sensors 41, 42 that detect the presence of the stack 9 at appropriate positions on the transport path (the position sensor 42 detects position P2 where the stack 9 no longer exists after first detecting its presence). If the first and second imaging means 21, 22 are provided at approximately the same position as in this example, the device can be made into a unit, making management and installation easier than when the imaging means are located at positions distant from each other.

[0026] 4 shows an example in which the first imaging means 21 and the second imaging means 22 are arranged on a common stand 7 to configure a unit. The figure is a view from the center of the conveying path, with the right side of the drawing being the upstream side in the conveying direction and the left being the downstream side. By arranging the first imaging means 21 and the second imaging means 22 vertically offset as in this example, the first imaging means 21 can be arranged on the downstream side and the second imaging means 22 on the upstream side so as to maintain a distance from each of the side surfaces 9a and 9b of the stack 9 while being at approximately the same position and without interfering with each other's imaging, and it is possible to increase the angle of view for each.

[0027] As a result, the distance between the unit and the side surface 9a / 9b of the stack 9 can be shortened, and the length of the stack transport path required for installation of this inspection device is shortened. In other words, this inspection device can be easily introduced, and the entire box making machine can be configured compactly, making it possible to perform inspection efficiently. In this example, each imaging means 21 / 22 is attached so that its position can be adjusted in the left-right direction along the frame 7a / 7b by plate nuts 25 and bolts 24 that can slide within the frame 7a / 7b that constitutes the stand 7.

[0028] The illumination means 3 is provided at a position opposite to the left / right of the positions of the first and second imaging means 21 across the transport path 10. Specifically, as shown in Fig. 3, a first illumination means 31 that obliquely illuminates the front side surface 9a and a second illumination means 32 that obliquely illuminates the rear side surface 9b are provided. By providing illumination for imaging on the opposite left and right sides in this manner and applying illumination from the side opposite to the left and right of imaging, it is possible to obtain a clear image with good contrast of the gap portion row 9G.

[0029] 5 shows an example of a specific configuration of the lighting means 3. A set of two vertically long LED lighting devices 33 are attached to the frame 71 in accordance with the height of the laminate 9, and the angle of each lighting device 33 can be adjusted so that it can illuminate a certain range on the left and right sides, including the gap portion row 9G on the side surface 9a (9b) of the laminate 9, from a nearby position.

[0030] In addition, in this example, an imaging means is provided on only one side, either the left or right, and inspection is performed based on the image captured from only that side. However, a preferred embodiment is one in which the first imaging means 21 and the second imaging means 22 are provided on both the left and right sides, respectively, so that the gap portion example 9G can be reliably imaged from both the left and right sides even in a laminate with a wide width, and the entire side surface 9a / 9b can also be imaged.

[0031] Specifically, as shown in FIG. 6, two pairs of the first imaging means 21 and the first lighting means 31 are provided so that the positions of the first imaging means 21 and the first lighting means 31 are opposite from each other (two pairs: a pair of 21A and 31A, and a pair of 21B and 31B), and two pairs of the second imaging means 22 and the second lighting means 32 are also provided so that the positions of the second imaging means 22 and the second lighting means 32 are opposite from each other (two pairs: a pair of 22A and 32A, and a pair of 22B and 32B), thereby preferably configuring so that the front and rear side surfaces 9a / 9b of the laminate 9 are imaged and illuminated from both the left and right.

[0032] In this case, it is efficient and preferable that the left and right imaging means and illumination means are each arranged on a common stand 7 as a unit configuration, as shown in Figure 7 (this is a view from the center of the conveying path as in Figure 4, with the right side of the page being the upstream side in the conveying direction and the left side being the downstream side).

[0033] 3, the quality inspection device 1 is provided with laser irradiation means 61, 62 that irradiate the regions of the side surfaces 9a, 9b imaged by the imaging means 2 with a line laser so that an irradiation line extends obliquely from the left / right lateral positions of the gap row 9G in the stacking direction (vertical direction) of the stack 9. By simultaneously imaging the irradiation line with the imaging means 2, it is possible to calculate the amount of misalignment of the overlapping of the boxes in a direction perpendicular to each of the side surfaces.

[0034] In other words, if there is a misalignment in the front-to-back direction when the boxes are stacked together, the width of the gap captured by the imaging means will be measured as smaller than the actual value for a box that is not concave (for example, a box that is concave and has shifted to the opposite side from the front or rear side being photographed (to the rear side if the side being photographed is the front, or to the front side if the side being photographed is the rear)), compared to a box that is not concave. If a line laser is simultaneously irradiated obliquely at this time, the irradiation line will be displayed as offset to the concave part of the box to the left and right opposite the installation position of the laser irradiation means 61 (62), as shown in the photograph in Figure 9, and this will be imaged.

[0035] By calculating the amount of this offset from the captured image, the degree of the dent in the box body can be grasped, and based on the degree of the dent, it is possible to grasp how small the width of the gap portion was captured and measured, and it becomes possible to correct the measurement value of the width of the gap portion. In this example, the laser irradiation means 61 (62) is provided only on the left or right side, which is the same as the imaging means that simultaneously captures images, but it may be provided on a different side from the imaging means, or it may be provided on both the left and right sides. In this example, a pair of laser irradiation means 61 and 62 that irradiate both side surfaces 9a and 9b of the laminate 9 is provided, but it may be provided only on one of them. In the example of FIG. 6, it is also preferable to provide the laser irradiation means 61 and 62 in the same manner.

[0036] The quality inspection device 1 includes a determination means for determining the quality of the joint based on the image of the row of gaps on each side surface captured by the imaging means. The determination means is provided by a control device 5, which is a control computer including a calculation unit 51 and a storage means 50, as shown in FIG.

[0037] Output signals from the imaging means 2 and position sensors 41, 42 are input to the calculation unit 51 through an input / output unit and a bus line (not shown). The calculation unit 51 is mainly composed of a CPU such as a microprocessor. The storage means 50 is composed of storage memories such as RAM and ROM, hard disks inside and outside the device, etc., and stores programs and processing data that define the procedures for various processing operations in the calculation unit 51. The control device 5 may be provided separately as a control device dedicated to the quality inspection device 1 according to the present invention, or may be configured as part of the control device of the box-making machine.

[0038] As shown in FIG. 8, the calculation unit 51 functionally comprises an operation control unit 51a that controls the operation of the imaging means 2 and the lighting means 3, a width dimension calculation unit 51b that calculates the width dimension of the gap portion 90g of each box body based on images of the gap portion rows 9G of each side surface 9a, 9b acquired from the imaging means 2, a deviation calculation processing unit 51c that calculates the amount of deviation in the front-to-rear direction of the overlap of each box body based on images of the irradiation lines of the laser irradiation means 61, 62 simultaneously acquired by the imaging means 2, and a judgment processing unit 51d that corrects the width of each gap portion 90g based on the width dimension calculated by the width dimension calculation unit 51b and the amount of deviation calculated by the deviation calculation processing unit 51c, and judges whether the corrected width is within a normal range, and these functions are realized by the above-mentioned program.

[0039] The operation control unit 51a detects the imaging positions of the front side surface 9a and the rear side surface 9b of the laminate 9 based on signals from the position sensors 41, 42, and operates the imaging means 2 and the illumination means 3 in accordance with this timing. The calculation of the width of the gap 90g by the width dimension calculation unit 51b is performed by recognizing the presence of the gap row and each of the gaps that constitute the gap row through image analysis, and measuring the width of each gap, as shown in Fig. 10.

[0040] Image analysis can be performed in the same manner as in Patent Document 1, for example, by converting the image into black and white and recognizing the gaps 90g consisting of black rectangles. The width can be measured based on the vertical dimension in Fig. 10, i.e., the predetermined thickness dimension of each cardboard, or by other methods. Here, it is also a preferred example to use the gaps (uniform) of the cutting blade processing on the right side of the row of gaps in Fig. 10 as the reference.

[0041] The deviation calculation processing unit 51c calculates the offset amount of the irradiation line from the image, and can calculate the deviation amount in the front-rear direction based on this offset amount and the irradiation angle with respect to the side surface. The storage means 50 stores data on the upper and lower limits indicating the normal range of the width of the gap portion 90g, image data of the gap portion row 9G imaged by the imaging means 2, and the like.

[0042] Although the embodiment of the present invention has been described above, the present invention is not limited to these embodiments, and it is of course possible to carry out the present invention in various forms without departing from the gist of the present invention. [Explanation of symbols]

[0043] 1. Quality inspection equipment 2. Imaging Method 3 Lighting means 5. Control device 7 Mounting 7a / 7b frame 8. String 9 Laminate 9G Gap row 9a, 9b side 10 Transport path 21 First imaging means 22 Second imaging means 24 Bordeaux 25 Plate Nut 31 First lighting means 32 Second lighting means 33 LED lighting equipment 41, 42 Position sensor 50 Memory means 51 Arithmetic section 51a Operation control unit 51b Width dimension calculation section 51c Displacement calculation processing unit 51d Judgment processing unit 61, 62 Laser irradiation means 71 Frames 90 box body 90f Flap 90g Gap

Claims

1. A method for inspecting the quality of a flat box formed by folding and gluing a sheet material, comprising the steps of: Among the side surfaces of the stacked body formed by stacking a plurality of the box bodies, for each of the two side surfaces on the flap side where the gap portions between the flaps formed by the joining are opened, an image of an area including at least a gap portion row in which the gap portions are arranged in the stacking direction is taken obliquely from a position on the left / right side of the gap portion row; determining whether the bonding is good or bad based on the captured images of the gap portion rows of each of the side surfaces; A quality inspection method comprising:

2. The quality inspection method according to claim 1 , wherein the imaging step images the region obliquely from a position within the same height range as the height of the stack.

3. A line laser is irradiated obliquely from a position on the left / right side of the row of gap portions to the region so that an irradiation line extends in the stacking direction; Calculating the amount of misalignment of the overlapping of the box bodies in a direction perpendicular to each of the side surfaces based on a state of the irradiation line displayed in the area by the irradiated line laser; The quality inspection method according to claim 1 , further comprising the step of judging whether the joint is good or bad based on the calculated amount of deviation and an image of the row of gaps.

4. 2. The quality inspection method according to claim 1, wherein, during the imaging, the region is illuminated obliquely from a lateral position opposite to the left or right of the imaging position.

5. The laminate is conveyed in a direction perpendicular to each of the side surfaces, The quality inspection method according to claim 1 , wherein the imaging is performed by imaging the front side and rear side of the stack in the transport direction of the stack being transported obliquely from positions on the left and right sides along the transport path of the stack.

6. A quality inspection device for a flat box formed by folding and gluing a sheet material, comprising: an imaging means for imaging an image of an area including at least a gap portion row in which the gap portions are arranged in the stacking direction for each of two side surfaces of the stack formed by stacking a plurality of the box bodies on the flap side where the gap portions are open due to the joining of the flaps, from a position on the left / right side of the gap portion row obliquely; an illumination means for illuminating the region obliquely from a position on the left / right side of the row of gaps; a determining means for determining whether the joining is good or bad based on the images of the gap portion rows of the side surfaces captured by the imaging means; Equipped with quality inspection equipment.

7. a laser irradiation means for irradiating the region with a line laser obliquely from a position on the left or right side of the row of gap portions so that an irradiation line extends in the stacking direction; a deviation calculation means for calculating a deviation amount of the overlapping of the box bodies in a direction perpendicular to each of the side surfaces based on a state of an irradiation line displayed in the area by the line laser irradiated by the laser irradiation means, 7. The quality inspection device according to claim 6, wherein the determining means determines whether the joint is good or bad based on the amount of misalignment calculated by the misalignment calculating means and an image of the row of gaps.

Images