Composite sheet manufacturing method and manufacturing device

Abstract

The present invention provides a method for manufacturing a composite sheet, comprising: a step of intermittently scattering powder (3) on a surface (1a) of a sheet (1) being conveyed in one direction (MD) to alternately form powder arrangement areas (5) and powder non-arrangement areas (6) in the MD; a sensing step of sensing the powder (3) scattering surface using a sensing mechanism (31); and an inspection step of inspecting the scattering state of the powder (3) based on the sensing data obtained by the sensing. In the inspection step, the position of the powder non-arrangement area (6) is detected, and based on the position information of the powder non-arrangement area (6), it is determined whether the scattering state of the powder (3) is good or not.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for producing a composite sheet produced through a step of intermittently spreading powder on the surface of the sheet. Background Art

[0002] Composite sheets manufactured by dispersing functional powders such as water-absorbing polymer particles and heat-generating particles throughout a sheet are well known. For such composite sheets to achieve their intended functions, it is crucial that the powder is dispersed as designed. Therefore, the powder dispersion has long been inspected in the manufacture of such composite sheets, and various techniques for this inspection have been proposed.

[0003] When inspecting the distribution of powder in a sheet, uneven texture can sometimes be mistakenly detected as powder, leading to a pressing need for technology that can detect powder with high accuracy. Patent Document 1 describes an inspection method that addresses this need. This method involves dividing an image of the powder extracted from a captured image of a sheet containing the powder into multiple regions, obtaining statistical values ​​based on the number of powder pixels, and determining the quality of the powder distribution based on these statistical values ​​for each region of the image. The inspection method described in Patent Document 1 is suitable for continuously dispersing powder on a sheet conveyed in a single direction.

[0004] Patent Document 2 describes a method for inspecting for poor application of an active material during the step of intermittently applying an ink-coated active material to a long sheet, specifically a long sheet formed of a laminate of an electrolyte membrane and a catalyst layer, passing through a roller. The inspection method described in Patent Document 2 is primarily characterized by irradiating the roller with inspection light, causing reflected light from the roller to illuminate the inspected sheet and transmit therethrough, and detecting the transmitted light with an inspection device.

[0005] Patent document 3 describes a method for simultaneously controlling the position of a patterned web in both the width direction and the length direction when the web is conveyed along the length direction, which includes two-dimensionally detecting the position of a pattern applied to the web being conveyed, and correcting the position of the web in the width direction and / or length direction by adjusting the direction of a position control roller, etc., upstream of the detection position of the pattern based on the offset of the detected two-dimensional position of the pattern from a prescribed reference position.

[0006] Patent Document 4 describes a method for controlling the positioning of a mark on a continuous web printed with a mark. The method described in Patent Document 4 includes: a step of reading the actual position (measured value) of a virtual master function formed by a periodic clock when the number of cycles per product, or in its place, the number of products per cycle, is an integer; a step of comparing the measured value with the expected position (target value) of the virtual master function; and a step of stretching the web in accordance with the deviation to minimize the deviation between the measured value and the target value.

[0007] Patent Document 5 describes a printing press suitable for cutting a printed web at a predetermined position. In this printing press, the web is fed at a low speed until printing begins (operating at production speed). During this low-speed operation, the web's elongation varies depending on the web's speed, and thus, the web's travel length in this operating area changes compared to that at production speed. This can lead to inaccurate positioning of the cut mark indicating the correct cutting position. The printing press described in Patent Document 5 addresses this issue. Based on the difference between the timing of web cutting by the cutting mechanism and the timing of the cut mark detection by the mark detector, the compensating roller is controlled to change the web's travel length, thereby adjusting the web's cutting position when the cutting mechanism cuts the web.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-39782

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-196570

[0012] Patent Document 3: Japanese Patent Application Laid-Open No. 2008-143699

[0013] Patent Document 4: Japanese Patent Application No. 2009-535617

[0014] Patent Document 5: Japanese Patent Application Laid-Open No. 2008-55783 Summary of the Invention

[0015] Technical problem to be solved by the invention

[0016] The present invention is a method for producing a composite sheet including a sheet and a powder disposed on a surface of the sheet.

[0017] One embodiment of the method for manufacturing a composite sheet of the present invention includes a powder spreading step of intermittently spreading powder on the surface of a sheet being conveyed in one direction, to alternately form powder arrangement areas and powder non-arrangement areas on the surface of the sheet in the one direction.

[0018] One embodiment of the method for producing a composite sheet of the present invention includes a sensing step of sensing the powder-scattered surface of the sheet using a sensing mechanism.

[0019] One embodiment of the method for producing a composite sheet of the present invention includes an inspection step of inspecting the dispersion state of the powder based on the sensing data acquired in the sensing step.

[0020] In one embodiment of the composite sheet manufacturing method of the present invention, in the inspection step, the position of the powder non-arrangement area is detected, and whether the powder dispersion state is good or not is determined based on the position information of the powder non-arrangement area.

[0021] Furthermore, the present invention provides an apparatus for producing a composite sheet including a sheet and powder disposed on a surface of the sheet.

[0022] In one embodiment of the composite sheet manufacturing device of the present invention, there is a powder spreading section that intermittently spreads powder on the surface of the sheet being transported in one direction, and alternately forms powder configuration areas and powder non-configuration areas on the surface of the sheet in the one direction.

[0023] In one embodiment of the composite sheet manufacturing apparatus of the present invention, a sensor unit is provided for sensing the powder scattered surface of the sheet using a sensor mechanism.

[0024] In one embodiment of the composite sheet manufacturing apparatus of the present invention, an inspection unit is provided for inspecting the dispersion state of the powder based on the sensing data acquired by the sensing unit.

[0025] In one embodiment of the composite sheet manufacturing apparatus of the present invention, the inspection unit detects the position of the powder non-arrangement region and determines whether the powder dispersion state is good or not based on the position information of the powder non-arrangement region.

[0026] Other features, effects, and embodiments of the present invention are described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of one embodiment of the composite sheet manufacturing apparatus of the present invention.

[0028] Figure 2 middle, Figure 2 (a) is a schematic plan view of an example of a composite sheet, Figure 2 (b) is shooting Figure 2 The actual image data obtained by the composite sheet shown in (a) is Figure 2 (c) is correct Figure 2The image data shown in (b) is image data to which pre-processing including binarization processing has been performed.

[0029] Figure 3 middle, Figure 3 (a) is an explanatory diagram of the edge detection process of the present invention, Figure 3 (b) is an explanatory diagram of edge detection processing outside the scope of the present invention.

[0030] Figure 4 middle, Figure 4 (a) is a schematic plan view of an example of image data of a non-defective product used in the quality determination of the present invention. Figure 4 (b) to Figure 4 (e) are respectively the image data of the inspection object Figure 4 The corresponding figure of (a).

[0031] Figure 5 This is a graph showing an example of powder dispersion control according to the present invention.

[0032] Figure 6 This is a graph showing another example of powder dispersion control according to the present invention. DETAILED DESCRIPTION

[0033] When powder is intermittently spread on a continuously conveyed sheet in the conveying direction, and powder-disposed areas and powder-non-disposed areas are alternately formed on the sheet surface in the conveying direction, the position of the powder-non-disposed areas may shift from the appropriate position due to factors such as clogging of the powder dispersing mechanism, resulting in dispersal disturbances, sheet breakage, or sheet stretching or slipping during sheet conveyance. Furthermore, when an adhesive is applied to the sheet before powder is spread, such adverse conditions may also occur due to factors such as poor application of the adhesive. Such positional shifts in the powder-non-disposed areas may adversely affect product performance. In the prior art, there is room for improvement in the accuracy of detecting the dispersion state when powder is intermittently spread.

[0034] Furthermore, immediately after the operation of a device (powder intermittent spreading device) that intermittently spreads powder on a continuously conveyed sheet in the conveying direction, alternating powder-distributed areas and powder-free areas on the sheet's surface in the conveying direction (the manufacturing startup step), that is, from the time the sheet's conveying stops until the sheet's conveying speed is accelerated to a predetermined target speed (the conveying speed for producing a qualified product), the sheet's conveying speed constantly changes. Unlike this, powder is intermittently spread at a constant rate, causing the powder-free areas to shift from their proper positions. Furthermore, the same problem of positional shifting of the powder-free areas exists during the period from the issuance of a stop command to the operating powder intermittent spreading device until it completely stops (the manufacturing shutdown step), as in the manufacturing startup step. Products manufactured in such a manufacturing startup or shutdown step, including the shifted powder-free areas, become defective products with unreliable product performance and, in practice, must be discarded. It is desirable to minimize such yield losses and improve productivity.

[0035] The present invention relates to a method and apparatus for manufacturing a composite sheet. When manufacturing a composite sheet by intermittently scattering powder on a continuously conveyed sheet in its conveying direction, the dispersion state of the powder can be inspected with high precision, and a composite sheet capable of stably exhibiting specified performance can be provided.

[0036] The present invention also relates to a method for producing a composite sheet, which can improve productivity in a production start-up step and a production stop-down step when producing a composite sheet by intermittently scattering powder on a continuously conveyed sheet in the conveyance direction.

[0037] The present invention will be described below with reference to the accompanying drawings based on preferred embodiments thereof. In the following drawings, identical or similar parts are designated by identical or similar reference numerals. The drawings are primarily schematic illustrations, and the proportions of various dimensions and the like may differ from actual proportions.

[0038] The present invention relates to the production of a composite sheet. The composite sheet, which is the production target of the present invention, comprises a sheet and powder disposed on the surface of the sheet.

[0039] The composite sheet typically has a laminated structure comprising a base layer formed of a sheet and a powder layer composed primarily of powder. The base layer and the powder layer may each be a multilayer structure of two or more layers. One embodiment of the composite sheet may include a structure in which a powder layer is interposed between two opposing base layers.

[0040] The material of the sheet is not particularly limited, and examples thereof include fiber sheets such as paper, woven fabric, and nonwoven fabric; and resin films. A composite sheet in which two or more of these materials are laminated may also be used.

[0041] The material of the powder is not particularly limited, and examples thereof include water-absorbing polymer particles, heat-generating (oxidizable metal) particles, and sodium chloride. These may be used alone or in combination of two or more.

[0042] The powder can be fixed to the sheet by a fixing means such as an adhesive, etc. In this case, typically, an adhesive is applied to the surface of the sheet where the powder is to be spread before the powder is spread.

[0043] Figure 1 A manufacturing apparatus 10 is shown as one embodiment of a composite sheet manufacturing apparatus according to the present invention. Manufacturing apparatus 10 includes: a powder spreading unit 20 for spreading powder 3 onto the surface 1a of a first sheet 1 being conveyed in one direction; an imaging unit 30 for capturing (sensing) the surface 1a (the surface on which the powder 3 is spread) using an imaging mechanism 31 (sensing device); and an inspection unit 40 for inspecting the distribution state of the powder 3 based on the image data (sensor data) acquired by the imaging unit 30 (sensing unit). Manufacturing apparatus 10 also includes a known conveying mechanism for conveying the sheet.

[0044] The composite sheet 4 manufactured by this embodiment has a structure in which powder 3 is interposed between the first sheet 1 and the second sheet 2 facing each other, and the powder 3 is bonded to the two sheets 1 and 2 via an adhesive (not shown). Figure 1 The structure shown is as follows: while a long strip-shaped first sheet 1, having a surface 1a coated with an adhesive such as a hot melt adhesive, is conveyed in its longitudinal direction, a powder 3 is spread on this surface 1a (the adhesive-coated surface) by a powder spreading unit 20. A long strip-shaped second sheet 2, having one surface coated with an adhesive such as a hot melt adhesive, is then superimposed on this surface 1a (the powder-coated surface) with the adhesive-coated surface of the second sheet 2 facing the surface 1a (the powder-coated surface), thereby producing a long strip-shaped composite sheet 4. This long strip-shaped composite sheet 4 is imaged by an imaging unit 30 and is the subject of inspection by an inspection unit 40.

[0045] Hereinafter, the conveyance direction of the first sheet 1 (composite sheet 4 ) is also referred to as “MD” (Machine Direction), and the direction perpendicular to the MD is also referred to as “CD” (Cross Machine Direction).

[0046] The powder spreading section 20 intermittently spreads powder 3 on the surface 1a of the first sheet 1 being conveyed on the MD, and on the surface 1a, powder arrangement areas 5 and powder non-arrangement areas 6 are alternately formed on the MD. Therefore, in the long strip-shaped composite sheet 4, the two areas 5 and 6 are alternately arranged in the longitudinal direction (MD) of the sheet 4. The powder non-arrangement area 6 is an area including a predetermined cutting portion when the long strip-shaped composite sheet 4 is cut to form a single-piece composite sheet 4. The manufacturing device 10 has a cutting section (not shown) provided with a cutting mechanism such as a knife at a position downstream of the MD than the camera mechanism 31. In this cutting section, the long strip-shaped composite sheet 4 after the camera step performed by the camera mechanism 31 is cut in the powder non-arrangement area 6, and a single-piece composite sheet 4 is continuously manufactured.

[0047] The powder dispersing unit 20 may be any device capable of dispersing the powder 3 intermittently, and any known powder dispersing device may be used without particular limitation. The powder 3 discharged from the powder dispersing unit 20 typically free-falls from a state of zero initial velocity to the target of dispersal. Alternatively, the powder 3 may be ejected from the powder dispersing unit 20 using an air flow, for example, to impart an initial velocity to the discharged powder 3.

[0048] In this embodiment, the powder spreading section 20 includes a powder storage section 21 and a discharge section 22 for discharging the powder 3 stored in the storage section 21 toward the first sheet 1 (to be spread). The powder spreading section 20 is disposed above the first sheet 1. The discharge section 22 does not contact the first sheet 1, and a space exists between the discharge section 22 and the first sheet 1. In the powder spreading step performed by the powder spreading section 20, as shown in FIG. Figure 1 As shown, the powder 3 is spread on the first sheet 1 without contact with the sheet 1, and the spread powder 3 reaches the sheet 1 by free fall.

[0049] The method for intermittently distributing the powder 3 by the powder distributing section 20 (discharge section 22) is not particularly limited. For example, the following methods may be used: 1) controlling the discharge / non-discharge operation of the powder 3 by the discharge section 22 so that the discharge of the powder 3 from the discharge section 22 is intermittent; or 2) instead of continuously discharging the powder 3 from the discharge section 22, a blocking device provided separately from the powder distributing section 20 is used to intermittently block the flow of the powder 3 from the discharge section 22 to the distribution target. As the blocking device, any known device can be used without particular limitation. For example, the device described in Japanese Patent No. 6247641 can be used.

[0050] In this embodiment, the method 1) described above is adopted. That is, the discharge unit 22 of this embodiment is configured to switch between discharging and non-discharging the powder 3 within the storage unit 21. By appropriately adjusting the discharge / non-discharge action of the discharge unit 22, the scattering cycle of the powder 3 (the time interval between one scattering and the next scattering) can be adjusted, thereby adjusting the position of the powder non-dispensing area 6 in the composite sheet 4. The switching of the discharge / non-discharge action of the discharge unit 22 is performed by the control unit 42 described below. In addition, when the method 2) described above is adopted, the operation of the above-mentioned blocking device is performed by the control unit 42 described below.

[0051] As an example of the powder spreading section 20, it is possible to cite: "A powder spreading device comprising: a hopper capable of storing powder inside and having a discharge port for the powder; and a conveying mechanism located below the hopper and conveying the powder discharged from the discharge port to a spreading position for spreading, the conveying mechanism comprising a receiving mechanism for receiving the powder discharged from the discharge port, and a vibration generating mechanism for vibrating the receiving mechanism, the receiving mechanism being vibrated by the vibration generating mechanism, thereby being able to convey the granular material on the receiving mechanism to the spreading position" (hereinafter also referred to as "specific powder spreading device"). In the above-mentioned specific powder spreading device, the above-mentioned hopper is equivalent to the storage section 21, and the above-mentioned conveying mechanism (the above-mentioned receiving mechanism and the above-mentioned vibration generating mechanism) is equivalent to the discharge section 22. By controlling the action of the above-mentioned vibration generating mechanism, the spreading period of the powder 3 can be adjusted, and thus the position of the powder non-configuration area 6 in the composite sheet 4 can be adjusted. As the specific powder dispersing device, for example, the powder dispersing device described in Japanese Patent Application Publication Nos. 2017-70944 and 2019-43735, or the device for transferring granular materials described in Japanese Translation of National Publication No. 2013-512047 can be used. When the specific powder dispersing device is used as the powder dispersing unit 20, the method 2) described above can also be employed. In this case, the flow of powder falling from the receiving mechanism toward the dispersing target (first sheet 1) can be intermittently blocked by the blocking device.

[0052] The imaging device 31 of the imaging unit 30 can be any imaging device that can be used to capture an object (composite sheet 4) traveling in one direction MD, without particular limitation. Examples include a line scan camera and a CCD area array camera. In particular, to facilitate image processing, an imaging device having an imaging element is preferably used, and a line scan camera is more preferably used. The imaging element can be a charge-coupled device (CCD) or a CMOS sensor. The imaging element can be a color imaging element.

[0053] The imaging unit 30 includes an illumination mechanism 32 for illuminating the subject. A power supply 33 is connected to the illumination mechanism 32 to supply power to the illumination mechanism 32. The illumination mechanism 32 can be any mechanism that provides sufficient brightness for the imaging unit 31, and the color and shape of the light source are not particularly limited. A specific example of the illumination mechanism 32 is a white light source. The intensity of the illumination light from the illumination mechanism 32 is adjusted based on the amount of power supplied to the illumination mechanism 32 by the power supply 33 so that the imaging unit 31 achieves appropriate exposure. As a result, the image captured by the imaging unit 31 has appropriate brightness, allowing the subject to be clearly captured.

[0054] In this embodiment, the composite sheet 4 as the object is photographed by using a transmitted light illumination method. Figure 1 As shown, a camera mechanism 31 is arranged on one side (above the subject) across the subject (composite sheet 4), and a lighting mechanism 32 is arranged on the other side (below the subject). The camera mechanism 31 captures the transmitted light emitted from the lighting mechanism 32 and passing through the subject.

[0055] In this embodiment, if Figure 1 As shown, the inspection unit 40 includes: an image processing unit 41, which controls the operation of the imaging device 31, processes and stores the image data obtained by the imaging device 31, and functions as a judgment unit 42 that judges whether the dispersion state of the powder 3 is good based on the image data output from the image processing unit 41.

[0056] The image processing unit 41 typically comprises a computer or an image controller installed with image processing software, etc., and has functions such as controlling the imaging unit 31, processing image data captured by the imaging unit 31, and storing the image data. The image processing unit 41 includes pre-processing such as edge detection, described later, on the image data, obtaining edge position information, and performing calculations prior to the control unit 42 determining whether the dispersion state of the powder 3 is satisfactory.

[0057] The control unit 42 is typically composed of a CPU, ROM, RAM, etc. In this embodiment, the control unit 42 not only functions as a determination unit that determines whether the dispersed state of the powder 3 is good or not based on the image data output from the image processing unit 41, but also has the function of controlling the dispersion of the powder 3 by the powder dispersion unit 20 based on the determination result. The control unit 42 is electrically connected to the discharge unit 22 constituting the powder dispersion unit 20. Switching between the discharge and non-discharge operations of the discharge unit 22 is controlled by the control unit 42.

[0058] In this embodiment, the inspection unit 40 includes an interface 43. The interface 43 is electrically connected to the control unit 42, thereby enabling the control unit 42 to be controlled based on an electrical signal manually input through the interface 43, and allowing warnings or fault conditions regarding the dispersion state of the powder 3 to be displayed on the interface 43 based on the electrical signal transmitted from the control unit 42.

[0059] Furthermore, in the present invention, the inspection unit 40 is not limited to the present embodiment as long as it can inspect the dispersion state of the powder 3 based on the image data acquired by the imaging unit 30. For example, the image processing unit 41 and the control unit 42 may cooperate to perform some or all of the aforementioned operations (acquisition of image data by the imaging unit 31, processing and storage of the acquired image data, and determination of whether the dispersion state of the powder 3 is satisfactory based on the image data). Alternatively, either the image processing unit 41 or the control unit 42 may perform all of the aforementioned operations. Furthermore, the inspection unit 40 may not include the interface 43.

[0060] In the manufacturing apparatus 10 having the above-described structure, the imaging mechanism 31 typically continuously captures images of the long strip-shaped composite sheet 4 being conveyed in one direction MD (imaging step), and the image data obtained by the imaging is stored in a time-series manner in the image processing unit 41 along with the number of imaging samples and the imaging sampling time. The image processing unit 41 controls imaging processing and image data, for example, by controlling the imaging speed of the imaging mechanism 31, controlling the start and stop of imaging, and controlling the writing and reading of image data.

[0061] Image data of the composite sheet 4 captured by the imaging mechanism 31 during a single imaging operation is aggregated into frames with a predetermined number of pixels, each capable of capturing data from the CD of the powder arrangement area 5 and the powder non-arrangement area 6 of the composite sheet 4 being transported. When the imaging mechanism 31 continuously captures the composite sheet 4 being transported multiple times, a series of multiple images, consisting of these frame-unit images connected in the CD, can be obtained. Arranging these multiple images in the order in which they were captured yields an image of the powder distribution surface of the composite sheet 4.

[0062] In this embodiment, the inspection unit 40, more specifically the image processing unit 41, pre-processes the image data obtained by the imaging device 31 to more accurately determine whether the dispersion state of the powder 3 is good or not. Known image processing methods can be used without particular limitation as pre-processing methods for this image data. Examples include binarization and filtering, either alone or in combination. An example of pre-processing of image data includes shading compensation to eliminate uneven texture, removing unnecessary noise from the image data, and then performing binarization.

[0063] exist Figure 2 The composite sheet 4 as the object to be inspected and the image thereof are shown in FIG. The composite sheet 4 as the object to be inspected is photographed by the imaging unit 31 and the illumination unit 32 having a white light source. Figure 2 The actual image data (unprocessed image data) obtained by photographing the composite sheet 4 shown in (a) is Figure 2 (b) The camera 31 captures the light transmitted through the composite sheet 4 in the illumination light generated by the illumination mechanism 32. The light transmitted through the sheets 1 and 2 but not through the powder 3. Figure 2 In the image data shown in (b), the white portion (white pixel) is the non-arrangement portion of the powder 3 (sheets 1 and 2), and the other portion (gray portion) is the powder 3. Figure 2 The inspection image data obtained by performing pre-processing including binarization processing on the image data shown in (b) is Figure 2 (c). Figure 2 In the image data shown in (c), the black portion (black pixel) is the powder 3, and the area where the black portion is concentrated is the powder arrangement area 5, and the area other than the black portion is the powder non-arrangement area 6. Figure 2 (b) and Figure 2 As can be seen from the comparison of (c), the powder 3 becomes more distinct by pre-processing such as binarization of the image data obtained by the imaging unit 31. Figure 2 As shown in (c), the inspection image data is used to perform edge detection processing described later, and edge position information and the like are obtained to determine whether the dispersion state of the powder 3 is good or bad.

[0064] The image processing unit 41 typically performs pre-processing of image data using a predetermined threshold value pre-set based on the quality of the composite sheet 4. For example, when the image processing unit 41 performs binarization as pre-processing, and the image data being binarized is image data captured using the transmitted light illumination method as described in this embodiment, a pre-set binarization threshold is used. Pixels with a higher image density (grayscale level) than the threshold are converted to "white" (the upper limit of the grayscale level: for example, grayscale level 255 in the case of the 256 grayscale levels from 0 to 255), representing the non-powder 3 area (powder non-placement area 6). On the other hand, pixels with a lower image density (grayscale level) than the threshold are converted to "black" (the lower limit of the grayscale level: for example, grayscale level 0 in the case of the 256 grayscale levels from 0 to 255), representing the powder 3. This generates binary image data consisting of two grayscale levels. The generated binary image data is written to and stored in the image processing unit 41 along with the corresponding image sampling time. The above-mentioned binarization threshold value can be set arbitrarily and appropriately, and can be set to a value that accurately identifies the pixels (imaged area) of the imaged powder 3. By flexibly utilizing the binary image data, the pixels of the powder 3 can be accurately identified, allowing for smoother and more accurate edge detection, as described later.

[0065] As one of the main features of the manufacturing apparatus 10, the following can be cited: the inspection unit 40 processes the image data obtained by the imaging unit 30, preferably Figure 2 As shown in (c), the image data is subjected to pre-processing including binarization processing and is the most suitable image data for inspection. Figure 3 As shown in (a), scanning is performed in both the MD and the direction opposite to the MD (anti-MD) to detect the boundary 7 in the MD between the powder arrangement area 5 and the powder non-arrangement area 6. Specifically, a feature of the manufacturing apparatus 10 is that the MD and anti-MD directions of the inspection object (composite sheet 4) are used as scanning directions in the edge detection processing of the image data. Figure 3 In (a), arrows indicated by symbols S1 and S2 respectively indicate scanning directions of image data. Direction S1 is the same direction as MD, and direction S2 is the opposite direction to MD.

[0066] Edge detection processing itself is well known. Typically, it involves detecting areas of pixel brightness within an image where grayscale values ​​vary significantly. In the present invention, any known detection method can be used as edge detection processing without particular limitation. For example, an example of edge detection processing is to extract areas where grayscale values ​​vary significantly based on the slope obtained by differentiating the grayscale values ​​in a direction S1 or S2.

[0067] In the edge detection process, when image data is scanned in one direction S1 or S2 , typically the entire length of the CD of the image data is scanned.

[0068] The scanning in one direction S1 or S2 ends at the moment when the edge 7 is detected, and detection of the edge 7 is not continued.

[0069] The edge detection process may be performed by the image processing unit 41 in parallel with the imaging by the imaging unit 31 , or may be performed after the imaging by the imaging unit 31 using the image processing unit 41 or another image processing device.

[0070] For example, Figure 3 In the image data 8 shown in (a), there is a powder arrangement region 5 located upstream of the MD (hereinafter also referred to as "upstream powder arrangement region 5A") and a powder arrangement region 5 located downstream of the MD (hereinafter also referred to as "downstream powder arrangement region 5B") across the powder non-arrangement region 6. Therefore, the downstream end 51 of the upstream powder arrangement region 5A and the upstream end 52 of the downstream powder arrangement region 5B exist as the edge 7. When scanning the image data 8 in one direction S1, the inspection unit 40 sequentially scans from the upstream end 8a of the image data 8 to the downstream end 8b. Conversely, when scanning the image data 8 in one direction S2, the inspection unit 40 sequentially scans from the downstream end 8b of the image data 8 to the upstream end 8a. In the scanning of the image data 8 in the direction S1 , the downstream end 51 of the upstream powder arrangement area 5A is detected as the edge 7 , and in the scanning of the image data 8 in the direction S2 , the upstream end 52 of the downstream powder arrangement area 5B is detected as the edge 7 .

[0071] As described above, in the above-mentioned edge detection processing, by scanning the image data of the inspection object in the direction S1 from the upstream side of the MD to the downstream side of the MD, and scanning in the opposite direction S2 of the direction S1, it is possible to suppress the false detection of the edge 7 and improve the detection accuracy of the edge 7, thereby enabling the dispersion state of the powder 3 to be inspected with high precision.

[0072] The effect of scanning the image data in both directions will be further described. In fact, it is very rare that there is no powder 3 in the powder non-arrangement area 6. The boundary 7 between the powder arrangement area 5 and the powder non-arrangement area 6 can be clearly identified. Figure 2 As shown in (c), in an area (powder non-arrangement area 6) where white pixels representing a non-arrangement portion of the powder 3 are concentrated, a plurality of black pixels representing the powder 3 are scattered. Figure 3The image data 8 shown schematically represents an example of image data in which powder 3 exists in such a powder non-arrangement region 6. It is ideal that there is no powder 3 in the powder non-arrangement region 6, but even when there is powder 3 in this region 6, if the amount of powder 3 present in this region 6 is a small amount that does not substantially affect the performance of the composite sheet 4, the powder 3 in this region 6 can be ignored. In this case, in the above-mentioned edge detection process, it is required not to mis-detect the powder 3 in the powder non-arrangement region 6 as an edge 7. Here, when scanning the image data of the inspection object only in one direction, specifically, for example, as shown in Figure 3 (b) of, when the image data 8 is scanned twice in one direction S2, since in the image data 8, as parts that can be detected as edges 7 (parts where the change in the gray level value in the pixel brightness of the image is relatively large), the upstream end 52 of the downstream powder arrangement region 5B, the powder 3 in the powder non-arrangement region 6, and the downstream end 51 of the upstream powder arrangement region 5A are arranged in sequence along the direction S2, so in these two scans, not only this upstream end 52, but also the powder 3 in this region 6 will be mis-detected as an edge 7, and the downstream end 51 that should originally be detected as an edge 7 may not be detected. In contrast, in the present embodiment, as shown in Figure 3 (a) of, the image data 8 is scanned in two opposite directions S1 and S2. Since the powder arrangement region 5 is scanned first compared to the powder non-arrangement region 6 in the scans in each direction S1 and S2, such mis-detection of the edge 7 can be prevented.

[0073] The inspection unit 40 detects the edge 7 based on the image data 8 of the inspection object as described above, and obtains the position information of the detected edge 7. As the position information of the edge 7, for example, the separation distance (coordinates of the edge 7) between the edge 7 and the upstream end 8a or the downstream end 8b of the image data 8 can be cited. In the present embodiment, as shown in Figure 3 (a) of, as the position information of the edge 7, the separation distance from the downstream end 8b of the image data 8 is adopted. In the figure, the symbol L1 is the separation distance between the edge 7 corresponding to the upstream end 52 of the downstream powder arrangement region 5B and the downstream end 8b of the image data 8, and the symbol L2 is the separation distance between the edge 7 corresponding to the downstream end 51 of the upstream powder arrangement region 5A and the downstream end 8b of the image data 8, and L1 < L2. The separation distances L1 and L2 can be values representing the position of this edge 7 on the coordinate axis of MD with the downstream end 8b of the image data 8 of the inspection object as the origin.

[0074] In addition, the total length of MD of the illustrated image data, represented by the image data 8, is the same as the total length (product length) of MD of a single composite sheet 4.

[0075] In this embodiment, the inspection unit 40 determines at least one of the "position of the powder non-contained area 6," the "MD length of the powder non-contained area 6," and the "area of ​​the powder non-contained area 6" based on the positional information of the edge 7, specifically, for example, at distances L1 and L2, for inspection (determining whether the powder non-contained area 6 is good or bad). Furthermore, this information derived from the positional information of the edge 7 (the position, MD length, and area of ​​the powder non-contained area 6) is also a type of positional information of the edge 7.

[0076] For example, refer to Figure 3 In (a), the position of the powder non-arrangement region 6 can be determined based on the position of the center of the MD of a pair of edges 7, 7 that pass through the front and rear ends of the MD of the region 6 and extend in the CD. Furthermore, the position of the center of the MD of the pair of edges 7, 7 can be determined based on the separation distances L1 and L2.

[0077] In addition, the length of the powder non-configuration area 6 on the MD can be determined based on the distance between a pair of edges 7, 7 that pass through the front and rear ends of the MD of the area 6 and extend on the CD. The distance can be obtained based on the difference (L2-L1) between the separation distance L2 and the separation distance L1.

[0078] The area of ​​the powder non-arrangement region 6 can be determined from the MD length ( L2 - L1 ) and CD length of the region 6 because the region 6 has a quadrilateral shape.

[0079] The inspection unit 40 determines the quality (goodness) of the dispersion state of the powder 3 within the inspection object (the object represented in the image data 8) based on the positional information of the edge 7 obtained from the image data of the inspection object and, if necessary, the position, MD length, and area of ​​the powder non-distribution area 6 determined from this positional information. If the inspection unit 40 determines that the powder 3 is good, it outputs an OK signal as a judgment signal; otherwise, it outputs an NG signal as a judgment signal. This signal is displayed on the interface 43, thereby providing information on the dispersion state of the powder 3 to the operator of the manufacturing apparatus 10.

[0080] The inspection unit 40 typically determines whether the dispersion of the powder 3 is satisfactory by comparing image data of the inspection object with a predetermined reference value (threshold value) for specified inspection items (such as the position of the powder non-distribution area 6 and the length and area of ​​the MD). These reference values ​​typically fall within a certain range. These reference values ​​are stored in a location accessible to the inspection unit 40 (control unit 42), and in this embodiment, are stored in the image processing unit 41.

[0081] If the numerical value of a predetermined inspection item in the image data of the inspection object falls within the aforementioned reference value range, the inspection object is judged as a qualified product with respect to the predetermined inspection item. Otherwise, the inspection object is judged as a defective product with respect to the predetermined inspection item. Basically, if all inspection items are judged as qualified, the inspection object is judged as a qualified product. Otherwise, the inspection object is judged as a defective product.

[0082] The above-mentioned reference value is set based on image data obtained by photographing a composite sheet of a good product with powder scattered as designed and the inspection object under the same conditions (hereinafter also referred to as "good product image data"). Figure 4 (a) shows the good product image data 80 as an example of the good product image data. The good product image data 80 is similar to the good product image data except that the powder 3 does not exist in the powder non-arrangement area 6. Figure 3 The image data 8 shown in (a) is basically the same. For example, the reference values ​​for "separation distances L1, L2," which can be one of the inspection items performed by the inspection unit 40, are set by setting the acceptable range for a good product based on the separation distances L1, L2 in the good product image data 80. The reference values ​​for other inspection items (e.g., the position of the powder non-arrangement area 6, the length and area of ​​the MD) are similar.

[0083] exist Figure 4 (b)~ Figure 4 In (e), as specific examples of the image data to be inspected, image data 81 to 84 are shown. All of the image data 81 to 84 are judged as defective products in the quality determination performed by the inspection unit 40.

[0084] exist Figure 4 In image data 81 shown in (b), the separation distances L1 and L2 exceed the upper limit of the range of predetermined reference values. The position of powder non-arrangement region 6 (the center position in the MD of the pair of edges 7, 7) is significantly offset upstream in the MD (towards upstream end 8a in the image data) compared to the position (proper position) of this region 6 in the acceptable product image data 80. Therefore, the inspection unit 40 determines that the portion of the long strip of composite sheet 4 corresponding to image data 81 is defective.

[0085] Figure 4 In the image data 82 shown in (c), the position of the powder non-arrangement region 6 is within the range of the predetermined reference value, indicating that the product is a good product. However, the MD length of this region 6 is below the lower limit of the predetermined reference value range and is shorter than the MD length (appropriate length) of this region 6 in the good product image data 80. Therefore, the inspection unit 40 determines that the portion of the long strip-shaped composite sheet 4 corresponding to the image data 82 is a defective product.

[0086] exist Figure 4 In the image data 83 shown in (d), the MD length of the powder non-arrangement region 6 exceeds the upper limit of the predetermined reference value range and is longer than the MD length (appropriate length) of the corresponding region 6 in the conforming product image data 80. Therefore, the inspection unit 40 determines that the portion of the long strip-shaped composite sheet 4 corresponding to the image data 83 is a defective product.

[0087] Figure 4 In the image data 84 shown in (e), the position and MD length of the powder non-arrangement region 6 are within the range of the specified reference values, indicating that the product is a good product. However, due to the presence of powder 3 in this region 6, the area of ​​the white portion of this region 6 is below the lower limit of the specified reference value range. Therefore, the inspection unit 40 determines that the portion of the long strip-shaped composite sheet 4 corresponding to the image data 84 is a defective product.

[0088] In this embodiment, the detection of the edge 7 and the acquisition of its positional information are performed by the image processing unit 41, and the determination of whether the dispersion state of the powder 3 is good or not based on the positional information of the edge 7 is performed by the control unit 42. Specifically, in this embodiment, the image processing unit 41 performs pre-processing including binarization on the image data acquired by the imaging unit 30, scans the pre-processed image data in both scanning directions S1 and S2 to detect the edge 7, acquires positional information of the detected edge 7 (such as the distances L1 and L2), and transmits this positional information to the control unit 42. Based on the positional information transmitted from the image processing unit 41, the control unit 42 determines whether the dispersion state of the powder 3 is good or not, and displays the determination result on the interface 43.

[0089] In this embodiment, as described above, the control unit 42 not only functions as a judgment unit for judging whether the dispersion state of the powder 3 is good, but also functions to control the dispersion of the powder 3 by the powder dispersion unit 20 based on the judgment result. That is, in this embodiment, the dispersion of the powder 3 by the powder dispersion unit 20 is controlled based on the position information of the edge 7. More specifically, Figure 1 As shown, the control unit 42 is electrically connected to the discharge unit 22 of the powder spreading unit 20. The control unit 42 generates a control signal for the discharge unit 22 based on the position information of the edge 7 obtained from the image data of the inspection object and sends it to the discharge unit 22. The discharge unit 22 executes or does not discharge the powder 3 according to the control signal.

[0090] However, the position information of the edge 7 used in the spreading of the powder 3 by the powder spreading unit 20 (powder spreading step) does not include information determined to be unnecessary in the inspection step by the inspection unit 40 (control unit 42). For example, the image data 81 to 84 (see Figure 4), are judged as defective in the quality determination by the inspection unit 40. Therefore, the position information of the edge 7, such as the position of the powder non-arrangement area 6 in these image data, is not used in generating the control signal sent to the discharge unit 22. As a result, the dispersion accuracy of the powder 3 by the powder spreading unit 20 is further improved, the powder non-arrangement area 6 can be arranged as designed, and the composite sheet 4 that can stably exhibit the specified performance can be manufactured more stably.

[0091] As described above, the inspection unit 40 (control unit 42) controls the spreading of the powder 3 by the powder spreading unit 20 (powder spreading step) based on the result of the determination of whether the spreading state of the powder 3 is good or not. As an example of the powder spreading control operation performed by the inspection unit 40, for example Figure 4 As shown in image data 81 shown in (b), when the position of the powder non-configuration area 6 (the center position of the MD of a pair of edges 7, 7) in the image data of the inspection object is greatly deviated from the appropriate position (prescribed reference value), a recovery action is performed to restore the position of the powder non-configuration area 6 to the appropriate position.

[0092] Figure 5 The diagram of FIG. 1 is an example of the above-mentioned recovery operation. Figure 5 The upper graph shows the relationship between the position (vertical axis) of the powder non-configuration area 6 in the long strip-shaped composite sheet 4 and the operating time (horizontal axis) of the manufacturing device 10. The vertical axis (Position) shows the position of the powder non-configuration area 6 on the coordinate axis of MD with the downstream side end 8b of the image data 8 of the inspection object as the origin.

[0093] In this example, the appropriate position of the powder non-arrangement area 6 is 215 mm upstream of the origin (downstream end 8b). The inspection results performed by the inspection unit 40 indicate that the position of the powder non-arrangement area 6 at the time of this inspection (the time of imaging by the imaging unit 30) is approximately 300 mm upstream of the origin in the MD, and is approximately 85 mm off from the appropriate position.

[0094] Therefore, in order to correct the positional deviation of the powder non-disposal area 6, the inspection unit 40 (control unit 42) controls the operation of the powder scattering unit 20, specifically the discharge / non-discharge operation of the powder 3 performed by the discharge unit 22, and adjusts the scattering cycle (recovery operation) of the powder 3. Figure 5 The lower graph is a graph showing ON / OFF (valid / invalid) of the control of the powder spreading unit 20 by the inspection unit 40. Figure 5The range indicated by "recovery operation" in the figure indicates that the control is ON (valid), that is, the operation (recovery operation) of the powder spreading unit 20 (discharge unit 22) under the control of the inspection unit 40 is being implemented. The recovery operation at this time is because the powder non-arrangement area 6 is larger than the appropriate position (refer to Figure 4 (a)) is offset to the upstream side of MD (refer to Figure 4 (b)), so it is an action for moving the powder non-configuration area 6 to the downstream side of the MD, specifically, it is an action for shortening the scattering cycle of the powder 3 compared to the current situation (shortening the time interval between one scattering and the next scattering compared to the current situation). Figure 5 As shown, the result of this recovery operation is that the offset is approximately zero, and the position of the powder non-arrangement area 6 is approximately aligned with the appropriate position. During the inspection step performed by the inspection unit 40, when the offset is confirmed to be approximately zero, the control of the powder spreading unit 20 by the inspection unit 40 is turned OFF (invalidated), and the recovery operation is terminated. In this specification, the phrase "approximately zero offset" means that during the inspection step performed by the inspection unit 40, the position of the powder non-arrangement area 6 is within a predetermined reference value (if the reference value is within a certain range, it is within that range).

[0095] The manufacturing device 10 has a defective product discharge mechanism (not shown) on the conveying path of the composite sheet 4, and can be configured to discharge the composite sheet 4 involved in the inspection object judged as a defective product in the inspection step performed by the inspection unit 40 from the conveying path (production line) using the defective product discharge mechanism. At this time, the inspection unit 40 (control unit 42) controls the operation of the above-mentioned defective product discharge mechanism, so that the judgment of whether the powder 3 is good or not and the discharge of defective products from the production line based on the judgment result can be performed more accurately and smoothly. As the above-mentioned defective product discharge mechanism, a mechanism that is well-known as a defective product discharge mechanism in such a production line can be appropriately utilized. The above-mentioned defective product discharge mechanism is typically arranged at a position downstream of the MD than the cutting portion (not shown) for cutting the long strip-shaped composite sheet 4, and discharges the single composite sheet 4 that is a defective product.

[0096] If a defective product is determined during the inspection step performed by the inspection unit 40, a recovery operation is performed, including the aforementioned powder dispersion control operation by the inspection unit 40 (control unit 42) and manual operation. This recovery operation is typically performed until the inspection step performed by the inspection unit 40 determines a product is acceptable. From the time the inspection unit 40 determines a defective product (when an NG signal is output) through the recovery operation until the time the inspection unit 40 determines a product is acceptable (when an OK signal is output), any composite sheet 4 that passes through the imaging unit 30 (imaging mechanism 31) is typically considered defective and is subject to discharge by the defective product discharge mechanism. Furthermore, each portion of the transported composite sheet 4, regardless of whether the composite sheet 4 is a single sheet or a long strip, can be identified by a distance calculated based on the number of products (single composite sheets 4) from a predetermined position on the transport path of the composite sheet 4 (e.g., the defective product discharge portion of the defective product discharge mechanism). This distance allows for the distinction between acceptable and defective products.

[0097] The above mainly describes the manufacturing apparatus of the composite sheet of the present invention. The following describes the manufacturing method of the composite sheet of the present invention based on the manufacturing method using the above-mentioned manufacturing apparatus 10. In the manufacturing method of the composite sheet described below, the description of the above-mentioned manufacturing apparatus 10 can be appropriately applied to the structure not specifically described.

[0098] like Figure 1 As shown, the method for manufacturing a composite sheet 4 using the manufacturing apparatus 10 includes: a powder spreading step of intermittently spreading the powder 3 onto the surface 1a of the sheet 1 being conveyed in one direction MD, and alternately forming the powder arrangement area 5 and the powder non-arrangement area 6 on the surface 1a in the one direction MD; a photographing step of photographing the powder-spreading surface (surface 1a) of the sheet 1 using a photographing device 31; and a photographing step of photographing the powder-spreading surface (surface 1a) of the sheet 1 based on the image data obtained by the photographing step (for example, Figure 4 The step of inspecting the dispersion state of the powder 3 is performed by using the image data 81 to 84 shown in FIG.

[0099] In the above inspection step, the position of the powder non-configuration area 6 is detected, and based on the position information of the powder non-configuration area 6, it is determined whether the dispersion state of the powder 3 is good (good / bad composite sheet 4) (refer to Figure 3 (a)). The "position of the powder non-arrangement area 6" referred to herein may be the position of the edge 7, which is the boundary on the MD between the powder arrangement area 5 and the powder non-arrangement area 6. The "position (information) of the edge 7" and the "position (information) of the powder non-arrangement area 6" below can be interchanged as appropriate.

[0100] In a preferred embodiment of the above-mentioned inspection step, the image data is scanned in both the MD and anti-MD directions to detect the boundary 7 on the MD between the powder arrangement area 5 and the powder non-arrangement area 6. Based on the position information of the edge 7, it is determined whether the dispersion state of the powder 3 is good (see Figure 3 (a)).

[0101] For the inspection object (long strip-shaped composite sheet 4) continuously conveyed in one direction MD, a series of processes consisting of the above-mentioned camera step and the above-mentioned inspection step are repeatedly performed. As a result, whether the dispersion state of the powder 3 is good or not can be judged with high precision for the inspection object as a whole. As a result, a composite sheet 4 that can stably perform the specified performance and has guaranteed product performance can be stably manufactured.

[0102] In the inspection step, at least one of the position, MD length, and area of ​​the powder arrangement region 5 may be obtained based on the position information of the powder non-arrangement region 6 and compared with a predetermined reference value.

[0103] In a preferred embodiment of the inspection step, at least one of the position, MD length, and area of ​​the powder non-arrangement region 6 may be obtained based on the position information of the edge 7 and compared with a predetermined reference value.

[0104] The image data inspected in the above inspection step may be subjected to pre-processing including binarization before inspection (see Figure 2 (c)).

[0105] For the inspection object (long strip-shaped composite sheet 4) continuously conveyed in one direction MD, a series of processes consisting of the above-mentioned camera step and the above-mentioned inspection step are repeatedly performed. As a result, for the entire inspection object, it is possible to judge with high precision whether the dispersion state of the powder 3 is good, and it is possible to judge with good precision whether the composite sheet 4 as the manufacturing target is good.

[0106] The scattering of the powder 3 in the above-mentioned powder scattering step can be controlled based on the position information of the edge 7 .

[0107] The position information of the edge 7 used in the powder scattering step preferably does not include information determined to be defective in the inspection step.

[0108] The above is mainly an explanation based on the state in which the manufacturing device 10 is in normal operation, that is, the conveying speed of the first sheet 1 to be sprinkled with powder 3 is maintained at a specified target speed (production speed) and the composite sheet 4 as a product is continuously manufactured. However, the present invention is also characterized in that a series of inspection processes including the above-mentioned camera steps and inspection steps are applied to at least one of the period from the operation of the manufacturing device 10 in the stopped state to the normal operation state (manufacturing startup step) and the period from the issuance of a stop command to the manufacturing device 10 in normal operation until the manufacturing device 10 is completely stopped (manufacturing stop step), and preferably to both.

[0109] Specifically, in the present invention, in a manufacturing start-up step in which the conveying of the first sheet 1 is accelerated from a stopped state to a prescribed target speed, or in a manufacturing stop step in which the conveying speed of the sheet 1 being conveyed at a prescribed target speed is decelerated and finally the conveying of the sheet 1 is stopped, the dispersion of the powder 3 in the above-mentioned powder dispersion step (a step of intermittently distributing powder 3 on the surface 1a of the sheet 1 being conveyed in one direction MD, and alternately forming powder distribution areas 5 and powder non-distribution areas 6 on the surface 1a in the one direction MD) is controlled based on the position information of the above-mentioned edge 7, specifically, for example, the "separation distances L1, L2" and the "position, MD length and area of ​​the powder non-distribution area 6".

[0110] In the present embodiment, by controlling the dispersion of the powder 3 based on the position information of the edge 7 , the occurrence rate of defective products in the manufacturing startup step or the manufacturing stop step can be reduced.

[0111] exist Figure 6 ] shows an example of the relationship between the position of the powder non-arrangement area 6 (vertical axis) and the number of products (horizontal axis) in the production start-up step and the production stop step. Figure 6 The vertical axis (Position) and Figure 5 The vertical axis of the image data is the same as that of the image data, and the position 215 mm away from the downstream end (origin) toward the upstream side of the MD is the appropriate position of the powder non-arrangement area 6. Figure 6 The "number of products" on the horizontal axis takes the position where the number of products in the composite sheet 4 is zero as the reference position, and the distance from the reference position to the inspection object area of ​​the sheet 4 is converted according to the number of products (single-piece composite sheet 4). The larger the value of the number of products, the farther the inspection object area is from the reference position. Figure 6 The range indicated by the symbol “N” indicates a period during which the manufacturing apparatus 10 is normally operated, that is, a period during which the conveying speed of the sheet (first sheet 1 ) is maintained at a predetermined target speed (production speed).

[0112] Figure 6The solid line indicated by the symbol "C0" represents the fluctuation in the position of the powder non-arrangement area 6 (the center position in the MD of the pair of edges 7, 7) when the powder dispersion control of the present invention, namely, "powder dispersion control based on edge position information," is not performed at all (hereinafter referred to as the "conventional method"). Focusing on the conventional method, the powder non-arrangement area 6 is located 170 mm upstream from the origin in the MD before the manufacturing apparatus 10 is operated. At this point in time, the deviation from the appropriate position is approximately 45 (=215 - 170) mm. During the manufacturing startup step from the start of operation of the manufacturing apparatus 10 until the sheet conveyance speed reaches the specified target speed (the speed during normal operation), the deviation decreases as the sheet conveyance speed increases. The deviation reaches approximately zero at the time of approximately 80 products. In this case, although the position of the powder non-arrangement area 6 varies depending on how the reference value (threshold) is set, if the reference value is zero, more than 80 products with non-zero deviations are discarded as yield losses. In addition, in the manufacturing stop step from the issuance of a stop command to the manufacturing device 10 in normal operation until the sheet conveying speed reaches zero, immediately after the stop command is issued, the offset increases in a downward and rightward direction as the sheet conveying speed decreases. Therefore, according to the above-mentioned reference value, immediately after the stop command is issued, there is a possibility that all the products to be inspected will be discarded as production loss.

[0113] In contrast, in the present invention, in order to reduce the yield loss in such a manufacturing start-up step and a manufacturing stop-down step, the spreading of the powder 3 by the powder spreading unit 20 in these steps is controlled based on the position information of the edge 7 obtained in the inspection step by the inspection unit 40. Specifically, for example, referring to Figure 6 The change in the position of the powder non-configuration area 6 in the manufacturing start step and the manufacturing stop step is Figure 6 The solid line shown by the symbol "C0" in FIG. 1 is used to control the discharge / non-discharge action of the powder 3 by the discharge unit 22 by setting a target that the offset amount becomes approximately zero. Figure 6 The "target of making the offset amount approximately zero" (position change pattern of the powder non-configuration area 6) mentioned here can also adopt the value of a predetermined appropriate position. In addition, as shown in FIG. Figure 6As shown by the dotted line C1, the position of the powder non-configuration area 6 can also gradually approach the value of the appropriate position. In the case where the change in the position of the powder non-configuration area 6 becomes as shown by the dotted line C1, in the manufacturing startup step, the number of products becomes less than that of the existing method (solid line C0), that is, the offset becomes approximately zero in a short time, and the state of the offset being approximately zero is maintained in the manufacturing startup step. In addition, in the manufacturing stop step, the same trend as that in the manufacturing startup step is observed. In the case where the change in the position of the powder non-configuration area 6 becomes as shown by the dotted line C1, the state of the offset being approximately zero is maintained for a relatively long time after the stop command is issued, and the rate of change of the offset thereafter becomes slower than that of the existing method. Therefore, by making the change in the position of the powder non-configuration area 6 become as shown by the dotted line C1, the yield loss in the manufacturing startup step and the manufacturing stop step can be effectively reduced.

[0114] In particular, in the present embodiment, the powder spreading step is configured such that the spread powder 3 reaches the first sheet 1 by free fall (see Figure 1 ), the free-fall velocity of the powder 3 is constant. However, during the production start-up and production stop steps, i.e., during the acceleration and deceleration of the sheet conveying speed, the conveying speed of the first sheet 1 varies constantly, and thus the position of the powder non-arrangement area 6 also varies constantly, which can easily lead to yield loss. According to the present invention, even in such a situation, yield loss can be effectively suppressed.

[0115] The position variation pattern of the target powder non-arrangement area 6 during the production startup step or the production stop step is pre-stored in a location (e.g., the image processing unit 41) that can be read by the inspection unit 40 (control unit 42) performing powder dispersion control. In this case, for example, the control unit 42 reads this position variation pattern during the production startup step and the production stop step, compares it with the position information of the edge 7 (specifically, the position information of the powder non-arrangement area 6) obtained from the image data of the inspection object, determines the difference between the two, and controls the discharge / non-discharge operation of the powder 3 by the discharge unit 22 to reduce the difference.

[0116] As mentioned above, although this invention was demonstrated based on the preferred embodiment, this invention is not limited to the said embodiment at all, It can change suitably within the range which does not deviate from the summary of this invention.

[0117] In the above embodiment, when determining whether the dispersion state of the powder 3 in the composite sheet 4 is good, the position information of the edge 7, including the position of the powder non-configuration area 6, the length and area of ​​the MD, is used as a judgment material. Furthermore, the gram weight (mass per unit area) of the powder 3 in the powder configuration area 5 can also be used as a judgment material. That is, in the above inspection step, the gram weight of the powder 3 in the powder configuration area 5 can be inspected, and the inspection unit 40 can also inspect the gram weight of the powder 3 in the powder configuration area 5. Because the main items inspected in the inspection step using the position information of the edge 7 as a judgment material are the state of the powder non-configuration area 6 (position, MD length, presence of powder 3 in the area 6, etc.), by further using the gram weight of the powder 3 in the powder configuration area 5 as a judgment material, the state of the powder configuration area 5 can be inspected. Through their synergistic effect, the distribution state of the powder 3 in the composite sheet 4 can be further inspected with high precision. As a method for inspecting the basic weight of the powder 3 , a known method for inspecting the basic weight can be used without particular limitation. For example, the method described in Patent Document 1 can be used.

[0118] In the above embodiment, the composite sheet as the manufacturing target is a structure in which the powder is interposed and arranged between two sheets, but the powder may be arranged on the surface of one sheet.

[0119] In the above embodiment, the imaging by the imaging unit is a transmitted light illumination method for imaging the transmitted light irradiated from the illumination means and passing through the inspection object, but instead, a reflected light illumination method may be used for imaging the reflected light irradiated from the illumination means and reflected from the inspection object.

[0120] In the above embodiment, an imaging mechanism is used as the sensing mechanism, and therefore image data is used as the sensor data. However, the sensing mechanism is not particularly limited as long as it can sense the powder distribution surface of the sheet. Of course, the sensor data is not limited to image data, and data corresponding to the sensing mechanism used can be used as appropriate.

[0121] Industrial Application Possibilities

[0122] According to the present invention, when manufacturing a composite sheet by intermittently scattering powder on a continuously conveyed sheet in its conveying direction, the dispersion state of the powder in the sheet can be inspected with high precision, and a composite sheet that can stably exhibit specified performance, that is, a composite sheet with guaranteed product performance, can be provided.

[0123] Furthermore, according to the present invention, when manufacturing composite sheets by intermittently scattering powder on a continuously conveyed sheet in its conveying direction, yield loss occurring in the production start-up and production stop steps can be effectively reduced, thereby improving production throughput.

Claims

1. A method for producing a composite sheet, the composite sheet comprising a sheet and a powder disposed on a surface of the sheet, the method comprising: a powder spreading step of intermittently spreading powder on the surface of a sheet being conveyed in one direction, thereby alternately forming powder arrangement areas and powder non-arrangement areas on the surface of the sheet in the one direction; a sensing step of sensing the powder spreading surface of the sheet using a sensing mechanism; and an inspection step of inspecting the dispersion state of the powder based on the sensing data obtained in the sensing step, In the inspection step, the position of the powder non-distribution area is detected by scanning the sensor data in both the conveying direction of the sheet and the direction opposite to the conveying direction, and whether the powder dispersion state is good is determined based on the position information of the powder non-distribution area. The scanning in the conveying direction and the direction opposite to the conveying direction respectively starts from the powder arrangement area and ends when the boundary, that is, the edge, between the powder arrangement area and the powder non-arrangement area in the conveying direction is detected.

2. The method for manufacturing a composite sheet according to claim 1, wherein: In a manufacturing start-up step from a state where the sheet conveyance is stopped until the sheet conveyance speed is accelerated to a predetermined target speed, or in a manufacturing stop step of decelerating the sheet conveyance speed while being conveyed at a predetermined target speed and finally stopping the sheet conveyance, the scattering of the powder in the powder scattering step is controlled based on the position information of the powder non-configuration area.

3. The method for producing a composite sheet according to claim 1 or 2, wherein: In the powder spreading step, the powder is spread on the sheet without contact with the sheet, and the spread powder reaches the sheet by free fall.

4. The method for producing a composite sheet according to claim 1 or 2, wherein: In the inspection step, at least one of the position, length in the conveying direction, and area of ​​the powder arrangement area is obtained based on the position information of the powder non-arrangement area, and compared with a predetermined reference value set in advance.

5. The method for producing a composite sheet according to claim 1 or 2, wherein: The sensor data inspected in the inspection step is subjected to pre-processing including binarization before inspection.

6. The method for producing a composite sheet according to claim 1 or 2, wherein: In the inspection step, the gram weight of the powder in the powder arrangement area is inspected.

7. The method for producing a composite sheet according to claim 1 or 2, wherein: The scattering of the powder in the powder scattering step is controlled based on the position information of the powder non-arrangement area.

8. The method for manufacturing a composite sheet according to claim 7, wherein: The position information of the powder non-arrangement region used in the powder scattering step does not include position information determined to be defective in the inspection step.

9. The method for producing a composite sheet according to claim 1 or 2, wherein: The position of the powder non-arrangement region is the position of an edge serving as a boundary between the powder arrangement region and the powder non-arrangement region in the sheet conveyance direction.

10. The method for producing a composite sheet according to claim 1 or 2, wherein: The sensing mechanism is a camera mechanism.

11. The method for producing a composite sheet according to claim 1 or 2, wherein: The sensing data is image data.

12. A device for manufacturing a composite sheet, the composite sheet comprising a sheet and a powder disposed on a surface of the sheet, the device comprising: a powder spreading section that intermittently spreads powder on the surface of a sheet being conveyed in one direction, thereby alternately forming powder arrangement areas and powder non-arrangement areas on the surface of the sheet in the one direction; a sensing portion for sensing the powder spreading surface of the sheet using a sensing mechanism; and an inspection unit that inspects the dispersion state of the powder based on the sensing data obtained by the sensing unit, The inspection unit scans the sensor data in two directions, namely, the sheet conveying direction and the direction opposite to the conveying direction, thereby detecting the position of the powder non-arrangement area, and judging whether the powder dispersion state is good or not based on the position information of the powder non-arrangement area. The scanning in the conveying direction and the direction opposite to the conveying direction respectively starts from the powder arrangement area and ends when the boundary, that is, the edge, between the powder arrangement area and the powder non-arrangement area in the conveying direction is detected.

13. The composite sheet manufacturing device according to claim 12, wherein: The inspection unit obtains at least one of the position, length in the conveying direction, and area of ​​the powder arrangement area based on the position information of the powder non-arrangement area, and compares the obtained value with a predetermined reference value set in advance.

14. The composite sheet manufacturing device according to claim 12 or 13, wherein: The inspection unit inspects the basis weight of the powder in the powder arrangement area.

15. The composite sheet manufacturing device according to claim 12 or 13, characterized in that: The scattering of the powder by the powder scattering section is controlled based on the position information of the powder non-arrangement area.

16. The composite sheet manufacturing device according to claim 12 or 13, characterized in that: The position of the powder non-arrangement region is the position of an edge serving as a boundary between the powder arrangement region and the powder non-arrangement region in the sheet conveyance direction.

17. The composite sheet manufacturing device according to claim 12 or 13, characterized in that: The sensing mechanism is a camera mechanism.

18. The composite sheet manufacturing device according to claim 12 or 13, wherein: The sensing data is image data.

Images