JP7411441B2 - Manufacturing method of composite sheet - Google Patents

Description

The present invention relates to a method for manufacturing a composite sheet, which is manufactured through a process of intermittently dispersing powder on the surface of the sheet.

BACKGROUND ART Composite sheets are known that are manufactured by scattering powders having some functionality, such as water-absorbing polymer particles or heating element particles, onto the sheet. In order for such a composite sheet to exhibit a predetermined function, it is important that the powder be spread as designed. Therefore, in the production of this type of composite sheet, the state of dispersion of powder has conventionally been inspected, and various techniques related to the inspection method have been proposed.

When inspecting the state of powder dispersion on a sheet, uneven formation of the sheet may be mistakenly detected as powder, and there has been a need for a technology that can detect powder with high accuracy. Regarding an inspection method that can meet such demands, Patent Document 1 discloses that an image of powder extracted from a captured image of a sheet on which powder is sprinkled is divided into a plurality of regions, and the powder is detected for each region of the image. An inspection method is described that includes the steps of obtaining statistical values based on the number of pixels, etc., and determining the quality of the powder dispersion state based on the statistical values. The inspection method described in Patent Document 1 is applied when powder is continuously sprinkled onto a sheet conveyed in one direction.

Patent Document 2 describes a method for simultaneously controlling the width direction and longitudinal position of a patterned web when the web is transported along the longitudinal direction. is detected two-dimensionally, and the position of the web in the width direction and/or longitudinal direction is detected based on the amount of deviation of the detected two-dimensional position of the pattern from a predetermined reference position. A method is described that includes a step of correcting the position by adjusting the orientation of the position control roll, etc., upstream of the position.

Patent Document 3 describes a method for controlling the positioning of marks on a continuous web on which marks are printed. The method described in Patent Document 3 calculates the actual position of a virtual main function such that the virtual main function consists of a periodic clock when the number of cycles per product or, alternatively, the number of products per cycle consists of an integer. (actual measurement value) at the time of detection, comparing the actual measurement value with the expected position (target value) of the virtual main function, and minimizing the deviation between the actual measurement value and the target value. elongating the material web in accordance with the deviation in order to increase the deviation.

Patent Document 4 describes a printing machine suitable for cutting a printed web at predetermined positions. In a printing press, the web is run at a low speed before printing starts (running at production speed), and work such as pre-supplying ink is performed while running at low speed, and the degree of elongation of the web depends on the running speed. As a result, in such a work area, the traveling path length changes compared to that at the production speed, and the position of the cut mark indicating the accurate cutting position may become inaccurate. The printing machine described in Patent Document 4 addresses this problem, and controls the compensator roller based on the difference between the timing at which the web is cut by the cutting device and the timing at which the cut mark is detected by the mark detector. The cutting position of the web by the cutting means is adjusted by changing the running path length of the web.

JP2019-39782A Japanese Patent Application Publication No. 2008-143699 Special Publication No. 2009-535617 Japanese Patent Application Publication No. 2008-55783

When powder is intermittently sprinkled on a continuously conveyed sheet in the conveyance direction to form powder placement areas and powder non-placement areas alternately on the surface of the sheet in the conveyance direction, powder The position of the non-powder area may deviate from the appropriate position due to disturbances in the dispersion due to clogging of the dispersion means, tearing of the sheet, elongation or slippage of the sheet during conveyance, and the like. Furthermore, when applying an adhesive to the sheet prior to powder dispersion, such inconveniences may occur due to poor application of the adhesive. Such misalignment of the powder non-arrangement area may have a negative effect on product performance. The conventional technology has room for improvement in terms of accuracy in detecting the dispersion state when powder is intermittently dispersed.

Further, an apparatus ( Immediately after the operation of the intermittent powder dispersion device, that is, the period during which the sheet conveyance speed is accelerated from the state where sheet conveyance has stopped to a predetermined target speed (the conveyance speed when manufacturing good products) (manufacturing start-up process) In this case, while the conveyance speed of the sheet changes from moment to moment, the powder is intermittently sprinkled at a constant period, so that the non-powder placement area shifts from an appropriate position. In addition, during the period from when a command to stop the operation of the intermittent powder dispersion device is issued to when it completely stops (production stoppage process), there is also the problem of misalignment of the non-powder placement area, similar to the production start-up process. There is. The reality is that products manufactured in such a manufacturing start-up process or manufacturing stoppage process have no choice but to be discarded because they are defective products that include misalignment in the non-powder placement area and cannot guarantee product performance. . It is desired to reduce such yield loss as much as possible and improve the yield.

An object of the present invention is to produce a composite sheet that can improve the yield in the production start-up process and production stop process when a composite sheet is manufactured by intermittently scattering powder in the conveyance direction of a continuously conveyed sheet. The present invention relates to providing a manufacturing method.

The present invention is a method for manufacturing a composite sheet, which includes a sheet and powder disposed on the surface of the sheet.
In one embodiment of the method for manufacturing a composite sheet of the present invention, powder is intermittently sprinkled on the surface of a sheet being conveyed in one direction, and a powder placement area and a powder non-placement area are formed on the surface of the sheet. The method includes a powder scattering step of alternately forming powder in one direction.
An embodiment of the method for manufacturing a composite sheet of the present invention includes an imaging step of imaging the powder-spreading surface of the sheet using an imaging means.
An embodiment of the composite sheet manufacturing method of the present invention includes an inspection step of inspecting the dispersion state of the powder based on the image data acquired in the imaging step.
In one embodiment of the method for manufacturing a composite sheet of the present invention, in the inspection step, the image data is scanned in the conveying direction of the sheet and in the opposite direction to the conveying direction to scan the powder placement area. An edge that is a boundary in the transport direction between the powder non-arranging area and the powder non-arranging area is detected, and based on the positional information of the edge, it is determined whether the composite sheet is a good product or a defective product.
In one embodiment of the method for manufacturing a composite sheet of the present invention, the sheet may be transported at a manufacturing start-up step in which the transport speed of the sheet is accelerated from a stopped state to a predetermined target speed, or during transport at a predetermined target speed. In the manufacturing stop step of reducing the conveyance speed of the sheet and finally stopping the conveyance of the sheet, the dispersion of the powder in the powder dispersion step is controlled based on the position information of the edge.
In one embodiment of the method for manufacturing a composite sheet of the present invention, in the production start-up step or the production stop step, by controlling the dispersion of the powder in the powder dispersion step based on the position information of the edge, The incidence of defective products in the manufacturing start-up process or the manufacturing stop process is reduced.
Other features, advantages and embodiments of the invention are described below.

According to the present invention, when manufacturing a composite sheet by intermittently sprinkling powder in the conveying direction of a continuously conveyed sheet, yield loss that occurs in the manufacturing start-up process and the manufacturing stop process is effectively reduced. yield is improved.

FIG. 1 is a schematic configuration diagram of an embodiment of a manufacturing apparatus that can be used to carry out the method for manufacturing a composite sheet of the present invention. FIG. 2(a) is a schematic plan view of an example of a composite sheet, FIG. 2(b) is actual image data obtained by imaging the composite sheet shown in FIG. 2(a), and FIG. 2(c) is a schematic plan view of an example of a composite sheet. ) is the image data shown in FIG. 2(b) subjected to preprocessing including binarization processing. FIG. 3(a) is an explanatory diagram of edge detection processing according to the present invention, and FIG. 3(b) is an explanatory diagram of edge detection processing outside the scope of the present invention. FIG. 4(a) is a schematic plan view of an example of non-defective image data used in the quality determination according to the present invention, and FIG. 4(b) to FIG. This is a diagram corresponding to FIG. 4(a). FIG. 5 is a graph showing an example of powder dispersion control according to the present invention. FIG. 6 is a graph showing another example of powder dispersion control according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on preferred embodiments thereof with reference to the drawings. In addition, in the description of the following drawings, the same or similar parts are given the same or similar symbols. The drawings are basically schematic, and the ratio of each dimension may differ from the actual one.

The present invention relates to the manufacture of composite sheets. The composite sheet that is the object of manufacture of the present invention comprises a sheet and powder disposed on the surface of the sheet.
A composite sheet typically has a laminated structure of a base material layer made of a sheet and a powder layer mainly composed of powder, and each of the base material layer and the powder layer has a plurality of two or more layers. It may be. One embodiment of the composite sheet includes one in which a powder layer is interposed between two opposing base material layers.
The material of the sheet is not particularly limited, and examples thereof include fiber sheets such as paper, woven fabric, and nonwoven fabric; resin films; and composite sheets in which two or more of these are laminated.
The material of the powder is not particularly limited, and examples include water-absorbing polymer particles, heating element (oxidizable metal) particles, sodium chloride, etc., and one of these may be used alone or two or more may be used in combination. Can be done.
The powder may be fixed to the sheet by a fixing means such as an adhesive. In that case, typically, before the powder is spread, an adhesive is applied to the surface of the sheet on which the powder is to be spread.

FIG. 1 shows a manufacturing apparatus 10 that is an embodiment of a manufacturing apparatus that can be used to carry out the method for manufacturing a composite sheet of the present invention. The manufacturing apparatus 10 includes a powder spreading section 20 that spreads powder 3 onto the surface 1a of the first sheet 1 being conveyed in one direction, and an imaging means 31 that images the surface 1a (the surface on which the powder 3 is spread). It has an imaging section 30 and an inspection section 40 that inspects the dispersion state of the powder 3 based on the image data acquired by the imaging section 30. The manufacturing apparatus 10 also includes a known transport mechanism for transporting sheets.

The composite sheet 4 manufactured in this embodiment has a structure in which powder 3 is interposed between a first sheet 1 and a second sheet 2 that face each other, and the powder 3 is interposed between both sheets 1 and 2. They are joined to each other via an adhesive (not shown). Corresponding to such a configuration of the object to be manufactured, the manufacturing apparatus 10, as shown in FIG. After the powder 3 is sprinkled on the surface 1a (adhesive application surface) by the powder scattering unit 20 while being conveyed in the direction, hot melt adhesive, etc. A long strip-shaped second sheet 2 coated with an adhesive is superimposed so that the adhesive-coated surface of the second sheet 2 and the surface 1a (powder dispersion surface) face each other to form a long strip-shaped second sheet 2. It is configured to manufacture a composite sheet 4. It is this long strip-shaped composite sheet 4 that is imaged by the imaging section 30 and is inspected by the inspection section 40 .
Hereinafter, the conveying direction of the first sheet 1 (composite sheet 4) is also referred to as "MD" (Machine Direction), and the direction perpendicular to MD is also referred to as "CD" (Cross machine Direction).

The powder scattering unit 20 intermittently sprinkles the powder 3 on the surface 1a of the first sheet 1 being conveyed to the MD, and creates a powder placement area 5 and a powder non-placement area 6 on the surface 1a in the MD. Form alternately. Therefore, in the long strip-shaped composite sheet 4, both regions 5 and 6 are arranged alternately in the longitudinal direction (MD) of the sheet 4. The powder non-arrangement area 6 is an area including a planned cutting site when cutting the long strip-shaped composite sheet 4 into a single sheet composite sheet 4. The manufacturing apparatus 10 has a cutting section (not shown) equipped with a cutting means such as a cutter on the downstream side of the MD from the imaging means 31, and the imaging process by the imaging means 31 is completed in the cutting section. The long strip-shaped composite sheet 4 is cut in the powder non-arrangement area 6 to continuously produce single-leaved composite sheets 4.

The powder dispersion unit 20 may be any device capable of dispersing the powder 3 intermittently, and any known intermittent powder dispersion device may be used without particular limitation. Typically, the powder 3 discharged from the powder scattering section 20 reaches the scattering target by free fall from a state of zero initial velocity, but instead of this, the powder is 3 may be ejected to give an initial velocity to the discharged powder 3.

In the present embodiment, the powder spreading section 20 includes a powder storage section 21 and a discharge section 22 that discharges the powder 3 stored in the storage section 21 toward the first sheet 1 (to be sprayed). Equipped with. The powder scattering section 20 is arranged above the first sheet 1, the discharge section 22 and the first sheet 1 are not in contact with each other, and a space exists between the discharge section 22 and the first sheet 1. In the powder dispersion process by the powder dispersion unit 20, as shown in FIG. Reach 1.

The intermittent spreading method of the powder 3 by the powder spreading section 20 (discharging section 22) is not particularly limited, and for example, 1) controlling the discharge/non-discharging operation of the powder 3 by the discharging section 22, Alternatively, 2) instead of continuously discharging the powder 3 from the discharge section 22, the powder 3 may be discharged from the discharge section 22 toward the target to be sprayed. A method may also be used in which the flow of the powder 3 is intermittently interrupted using a blocking device provided separately from the powder dispersing section 20. As the shutoff device, any known one can be used without particular limitation. As the cutoff device, for example, a device described in Japanese Patent No. 6247641 can be used.

In this embodiment, the above 1) is adopted. That is, the discharge section 22 of this embodiment is configured to be able to switch between discharging and non-discharging the powder 3 in the storage section 21, and by adjusting the discharging/non-discharging operation of the discharging section 22 as appropriate, The sprinkling period of the powder 3 (the time interval between one sprinkling and the next sprinkling) can be adjusted, and thereby the position of the powder non-arrangement area 6 on the composite sheet 4 can be adjusted. Switching of the discharge/non-discharge operation of the discharge section 22 is performed by a control section 42, which will be described later. In addition, when employ|adopting said 2), the operation|movement of the said cutoff device is performed by the control part 42 mentioned later.

An example of the powder scattering section 20 is a hopper that can store powder inside and has a discharge port for the powder, and a hopper that is located below the hopper and that discharges the powder from the discharge port. a conveying means for conveying the powder to a dispersing position and dispersing the powder; the conveying means has a receiving means for receiving the powder discharged from the discharge port; and a vibration generating means for vibrating the receiving means; "Powder dispersing device" (hereinafter also referred to as "specific powder dispersing device"), which is capable of transporting the granules on the receiving means to the dispersing position by vibrating the receiving means with a vibration generating means. ). In the specific powder scattering device, the hopper corresponds to the storage section 21, and the conveying means (the receiving means and the vibration generating means) corresponds to the discharging section 22. By controlling the operation of the vibration generating means, it is possible to adjust the dispersion period of the powder 3 and, by extension, the position of the powder non-arrangement area 6 on the composite sheet 4. As the specific powder dispersion device, for example, the powder dispersion device described in JP 2017-70944A and JP 2019-43735A or the particulate material transfer device described in Japanese Patent Application Publication No. 2013-512047 A device for this purpose can be used. The specific powder dispersing device may be used as the powder dispersing unit 20, and 2) above may be adopted, in which case the flow of powder falling from the receiving means toward the target to be sprayed (first sheet 1). may be intermittently shut off by the shutoff device.

As the imaging means 31 included in the imaging unit 30, any device that can be used for imaging an object to be imaged (composite sheet 4) traveling in one direction MD can be used without particular limitation, such as a line scan camera, a CCD system, etc. area cameras. In particular, in order to facilitate image processing, it is preferable to use an imaging device having an image sensor, and it is more preferable to use a line scan camera. The image sensor may be a charge coupled device (CCD) or a CMOS sensor. The image sensor may be a color image sensor.

The imaging unit 30 includes an illumination unit 32 that irradiates light onto an object to be imaged. A power source 33 that supplies power to the illumination means 32 is connected to the illumination means 32 . The illumination means 32 may be anything that can provide sufficient brightness for imaging by the imaging means 31, and there are no particular restrictions on the color or shape of the light source. A specific example of the illumination means 32 is a white light source. The intensity of the illumination light from the illumination means 32 is adjusted by the amount of power supplied to the illumination means 32 by the power source 33 so that the image taken by the image pickup means 31 has proper exposure. As a result, the image obtained by the imaging means 31 has appropriate brightness, and the object to be imaged is clearly imaged.

In this embodiment, the composite sheet 4, which is the object to be imaged, is imaged using a transmitted light illumination method. Specifically, as shown in FIG. 1, an imaging means 31 is provided on one side (above the object) with the object (composite sheet 4) in between, and an illumination means 32 is provided on the other side (below the object). The imaging means 31 images the transmitted light emitted from the illumination means 32 and transmitted through the object to be imaged.

In this embodiment, as shown in FIG. 1, the inspection section 40 includes an image processing section 41 that controls the operation of the imaging means 31, processes and saves image data acquired by the imaging means 31, and an image processing section 41 that performs the image processing. The control section 42 functions as a determination section that determines whether the dispersion state of the powder 3 is good or bad based on the image data output from the section 41.

The image processing unit 41 typically has a control function for the imaging means 31, a processing function for image data captured by the imaging means 31, a storage function for the image data, etc., and has image processing software etc. installed therein. It is configured as a device based on a computer and an image controller. The image data processing function of the image processing unit 41 includes, before the control unit 42 determines whether the dispersion state of the powder 3 is good or bad, the image data is subjected to preprocessing such as edge detection processing, which will be described later, to obtain edge position information, etc. Contains functions to obtain and calculate.

The control unit 42 typically includes a CPU, ROM, RAM, and the like. In this embodiment, the control unit 42 functions as a determination unit that determines whether the dispersion state of the powder 3 is good or bad based on the image data output from the image processing unit 41, and also functions as a determination unit that determines the quality of the dispersion state of the powder 3 based on the determination result. It has a function of controlling the dispersion of the powder 3 by the dispersion section 20, and is electrically connected to the discharge section 22 that constitutes the powder dispersion section 20. The above-mentioned switching of the discharge/non-discharge operation of the discharge section 22 is controlled by the control section 42 .

In this embodiment, the inspection unit 40 includes an interface 43. The interface 43 is electrically connected to the control unit 42, and thereby controls the control unit 42 based on the electric signal manually input via the interface 43. Based on this, it becomes possible to display warnings, problems, etc. regarding the dispersion state of the powder 3 on the interface 43.

In the present invention, the inspection section 40 may be any device that can inspect the dispersion state of the powder 3 based on the image data acquired by the imaging section 30, and its device configuration is not limited to the present embodiment. For example, the image processing unit 41 and the control unit 42 cooperate to perform the above-mentioned operations (acquisition of image data by the imaging means 31, processing and storage of the acquired image data, changing the dispersion state of the powder 3 based on the image data). (quality determination, etc.) may be executed in part or in whole, or either one of the image processing section 41 and the control section 42 may execute all of the above operations. Furthermore, the inspection section 40 does not need to include the interface 43.

In the manufacturing apparatus 10 having the above-described configuration, typically, the long strip-shaped composite sheet 4 being conveyed in one direction MD is continuously imaged by the imaging means 31 (imaging step), and the images are acquired by the imaging. The image data is stored in the image processing unit 41 in time series along with the number of imaging samplings and the imaging sampling time. The image processing unit 41 performs control related to imaging processing and image data, such as controlling the imaging speed by the imaging means 31, starting and stopping imaging, and controlling writing and reading of image data.
The image data of the composite sheet 4 that is imaged by the imaging means 31 in one imaging operation is collected from predetermined pixels that can capture CD data including the powder placement area 5 and the powder non-placement area 6 in the composite sheet 4 being conveyed. It is organized into a number of frames. When the composite sheet 4 being conveyed is continuously imaged a plurality of times by the imaging means 31, a series of a plurality of images in which such frame-by-frame images are continuous on the MD can be acquired. By arranging the series of plural images in the order in which they were taken, an image of the powder-spreading surface of the composite sheet 4 is obtained.

In the present embodiment, more specifically, the image processing unit 41 performs a quality judgment based on the image data acquired by the imaging means 31 in order to more accurately judge the quality of the dispersion state of the powder 3. Prior to this, the image data is subjected to preprocessing. As a pre-processing method for such image data, known image processing can be used without particular restrictions, such as binarization processing, filter processing, etc., and one may be used alone, or two may be used. The above may be used in combination. As an example of pre-processing of image data, image data acquired by the imaging means 31 is subjected to shading correction to remove uneven texture, etc., to remove noise that becomes extra information from the image data, and then binarized. Examples include processing that performs processing.

FIG. 2 shows a composite sheet 4, which is an object to be inspected and an object to be imaged by the imaging means 31, and its captured image. Actual image data (unprocessed image data) obtained by imaging the composite sheet 4 shown in FIG. This is shown in FIG. 2(b). What the imaging means 31 images is the transmitted light of the composite sheet 4 in the illumination light from the illumination means 32. The transmitted light passes through the sheets 1 and 2 but does not pass through the powder 3, so as shown in FIG. In the image data shown in b), the white parts (white pixels) are the parts (sheets 1 and 2) where the powder 3 is not placed, and the other parts (gray parts) are the powder 3. The image data for inspection obtained by performing preprocessing including binarization processing on the image data shown in FIG. 2(b) is shown in FIG. 2(c). In the image data shown in FIG. 2(c), the black part (black pixel) is the powder 3, the area where a large number of the black parts are present is the powder placement area 5, and the other area is the powder placement area 5. This is a powder non-arrangement area 6. From the comparison between FIG. 2(b) and FIG. 2(c), it is clear that the powder 3 becomes clearer by performing pre-processing such as binarization processing on the image data acquired by the imaging means 31. be. In this embodiment, using inspection image data as shown in FIG. 2(c), edge detection processing, which will be described later, is performed, edge position information, etc. is acquired, and the quality of the dispersion state of the powder 3 is determined. .

Pre-processing of the image data by the image processing unit 41 is typically performed using a predetermined threshold value set in advance based on the composite sheet 4 of good quality. For example, when the image processing unit 41 performs binarization processing as preprocessing, the image data to be binarized is captured using a transmitted light illumination method as in this embodiment. , a binarization threshold is set in advance, and pixel parts with image density (gradation) higher than the binarization threshold are marked as "white" (gradation upper limit: for example, 256 gradations from 0 to 255). If so, it is converted to 255 gradations) to indicate the part where the powder 3 is not placed (powder non-placement area 6). On the other hand, pixel portions with image density (gradation) lower than the binarization threshold are converted to "black" (lower limit of gradation: for example, 0 gradation for 256 gradations from 0 to 255), Powder 3 is shown. In this way, binary image data consisting of two gradations is generated. The generated binary image data is written and stored in the image processing unit 41 together with the imaging sampling time that the corresponding image data has. The binarization threshold value can be arbitrarily set as appropriate, and can be set to a value that allows the pixels (imaging area) of the imaged powder 3 to be accurately grasped. By utilizing the binarized image data, it becomes possible to accurately grasp the pixels of the powder 3, and it becomes possible to perform edge detection, which will be described later, more accurately and smoothly.

One of the main features of the manufacturing apparatus 10 is that the inspection section 40 performs preprocessing including binarization processing on the image data acquired by the imaging section 30, preferably on the image data as shown in FIG. 2(c). The image data optimized for inspection is scanned in both the MD and the direction opposite to the MD (anti-MD), as shown in FIG. An example of this is detecting an edge 7 that is a boundary in MD with a non-placement area 6. That is, the manufacturing apparatus 10 is characterized in that it employs two directions, MD and anti-MD, of the inspection object (composite sheet 4) as scanning directions in edge detection processing of image data. In FIG. 3A, arrows indicated by symbols S1 and S2 respectively indicate the scanning direction of image data, where direction S1 is the same direction as MD, and direction S2 is opposite MD.

Edge detection processing itself is well known, and typically involves detecting a portion where the tone value changes significantly in pixel brightness of an image. In the present invention, as the edge detection process, a known detection processing method can be used without particular limitation. For example, a change in tone value is based on a gradient obtained by differentiating the tone value in one direction S1 or S2. An example of processing for extracting locations where is large can be given.

In edge detection processing, when image data is scanned in one direction S1 or S2, typically the entire CD length of the image data is scanned.
The scanning in one direction S1 or S2 ends when the edge 7 is detected, and the edge 7 is not detected subsequently.
The edge detection process may be performed by the image processing section 41 in parallel with the imaging by the imaging means 31, or may be performed using the image processing section 41 or another image processing device after the imaging by the imaging means 31.

For example, the image data 8 shown in FIG. 3(a) includes a powder placement area 5 (hereinafter also referred to as "upstream powder placement area 5A") located on the upstream side of the MD across the powder non-placement area 6. ) and a powder placement area 5 located on the downstream side (hereinafter also referred to as "downstream powder placement area 5B"). There is an end 51 and an upstream end 52 of the downstream powder placement area 5B. When scanning the image data 8 in one direction S1, the inspection unit 40 sequentially scans the image data 8 from the upstream end 8a to the downstream end 8b, and when scanning the image data 8 in one direction S2, the inspection unit 40 scans the image data 8 in one direction S2. , on the contrary, the image data 8 is sequentially scanned from the downstream end 8b toward the upstream end 8a. When the image data 8 is scanned in the direction S1, the downstream end 51 of the upstream powder placement area 5A is detected as the edge 7, and when the image data 8 is scanned in the direction S2, the upstream end 51 of the downstream powder placement area 5B is detected as the edge 7. Side edge 52 is detected as edge 7 .

In this way, in the edge detection process, the image data to be inspected is scanned in the direction S1 from the upstream side of the MD to the downstream side of the MD, and also in the direction S2 opposite to the direction S1, so that the edge 7 Error detection is suppressed, and the detection accuracy of the edge 7 is improved, thereby making it possible to inspect the quality of the dispersion state of the powder 3 with high precision.
To further explain the effects of such bidirectional scanning of image data, there is no powder 3 in the powder non-placement area 6, and the boundary between the powder placement area 5 and the powder non-placement area 6, that is, the edge 7. In reality, it is rare to be able to clearly identify the area where the powder 3 is not placed (powder non-placement area 6), as shown in FIG. ), a plurality of black pixels indicating powder 3 are scattered. Image data 8 shown in FIG. 3 schematically shows an example of image data in which powder 3 is present in such powder non-arrangement area 6. Ideally, no powder 3 exists in the non-powder placement area 6, but even if powder 3 exists in the area 6, the amount of powder 3 present in the area 6 will be smaller than the amount of powder 3 in the composite sheet 4. The powder 3 in the region 6 can be ignored if the amount is small enough to not substantially adversely affect performance. In that case, it is desired that the powder 3 in the powder non-arrangement area 6 is not erroneously detected as the edge 7 in the edge detection process. Here, when the image data to be inspected is scanned in only one direction, specifically, as shown in FIG. 3(b), when the image data 8 is scanned twice in one direction S2, the image data 8 Here, the powder in the upstream end 52 of the downstream powder placement area 5B and the powder non-placement area 6 is a portion that can be detected as an edge 7 (a portion where the change in gradation value is relatively large in the pixel brightness of the image). 3. Since the downstream end 51 of the upstream powder placement area 5A is arranged in this order along the direction S2, in the two scans, in addition to the upstream end 52, the powder in the area 6 is There is a possibility that the body 3 will be erroneously detected as the edge 7, and the downstream end 51, which should originally be detected as the edge 7, will not be detected. On the other hand, in this embodiment, as shown in FIG. Since the powder arrangement region 5 is scanned in the same manner, such erroneous detection of the edge 7 can be prevented.

The inspection unit 40 detects the edge 7 from the image data 8 to be inspected as described above, and acquires position information of the detected edge 7. As the positional information of the edge 7, for example, the distance between the edge 7 and the upstream end 8a or the downstream end 8b of the image data 8 (coordinates of the edge 7) can be mentioned. In this embodiment, as shown in FIG. 3A, the distance from the downstream end 8b of the image data 8 is used as the position information of the edge 7. In the figure, the symbol L1 is the 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 downstream end of the upstream powder arrangement region 5A. This is the separation distance between the edge 7 corresponding to the side edge 51 and the downstream edge 8b of the image data 8, and L1<L2. The separation distances L1 and L2 can indicate the position of the edge 7 in the MD coordinate axis whose origin is the downstream end 8b of the image data 8 to be inspected.
Note that the total MD length of the illustrated image data including the image data 8 corresponds to the total MD length (product length) of the single composite sheet 4.

In this embodiment, the inspection unit 40 determines the "position of the powder non-arrangement area 6" and "MD of the powder non-arrangement area 6" based on the position information of the edge 7, specifically, for example, the separation distances L1 and L2. At least one of "length" and "area of powder non-arrangement area 6" is determined and used for inspection (good/failure determination). Note that these pieces of information derived from the position information of the edge 7 (the position of the powder non-arrangement region 6, the length and area of the MD) are also a type of position information of the edge 7.
For example, referring to FIG. 3(a), the position of the powder non-arrangement area 6 is specified by the position of the center of the MD of a pair of edges 7, 7 extending to the CD through the front and rear ends of the MD of the area 6. be able to. Further, the position of the center of the MD of the pair of edges 7, 7 can be determined from the separation distances L1, L2.
Further, the length of the MD of the powder non-arrangement region 6 can be specified by the distance between a pair of edges 7, 7 extending to the CD through the front and rear ends of the MD of the region 6, and the distance is It can be determined from the difference (L2-L1) between distance L2 and separation distance L1.
Furthermore, since the area 6 has a rectangular shape, the area of the powder non-arrangement area 6 can be determined from the MD length (L2-L1) and the CD length of the area 6.

The inspection unit 40 determines the position information of the edge 7 acquired from the image data of the inspection target, and if necessary, any one of the position of the powder non-arrangement area 6, the length and area of the MD determined from the position information. Based on the above, it is determined whether the state of dispersion of the powder 3 on the inspection object (the imaged object reflected in the image data 8) is good or bad. Then, the inspection unit 40 outputs an OK signal as a determination signal in the case of a non-defective determination, and outputs an NG signal as a determination signal in other cases. Such a signal is displayed on the interface 43, thereby providing the operator of the manufacturing device 10 with information regarding the dispersion status of the powder 3.

The inspection unit 40 typically determines the quality of the dispersion state of the powder 3 by comparing the image data of the inspection target with respect to predetermined inspection items (the position of the powder non-arrangement area 6, the length and area of the MD, etc.). , is performed by comparing with a predetermined reference value (threshold value) set in advance. The reference value typically has a certain range. The reference value is stored in a location that can be read by the inspection unit 40 (control unit 42), and in this embodiment, it is stored in the image processing unit 41.
If the numerical value of a predetermined inspection item in the image data of the inspection target is within the range of the reference value, the inspection target is determined to be a non-defective product with respect to the predetermined inspection item. The product is determined to be defective regarding the inspection items. Basically, when all inspection items are determined to be non-defective, the inspection target is determined to be non-defective, and in other cases, the inspection target is determined to be defective.

The reference value is set based on image data (hereinafter also referred to as "non-defective image data") obtained by imaging a non-defective composite sheet on which powder has been scattered as designed under the same conditions as the inspection target. . FIG. 4A shows non-defective image data 80, which is an example of the non-defective image data. The non-defective product image data 80 is basically the same as the image data 8 shown in FIG. 3A, except that the powder 3 is not present in the powder non-arrangement area 6. For example, the reference value of "separation distance L1, L2", which can be one of the inspection items by the inspection unit 40, is set by setting a range that is acceptable as a non-defective product based on the separation distances L1, L2 of the non-defective product image data 80. The same applies to the reference values of other inspection items (for example, the position of the powder non-arrangement region 6, the length and area of the MD).

FIGS. 4(b) to 4(e) show image data 81 to 84 as specific examples of image data to be inspected. All of the image data 81 to 84 are determined to be defective products by the quality determination by the inspection unit 40.
In the image data 81 shown in FIG. 4(b), the separation distances L1 and L2 exceed the upper limit of the predetermined reference value range, and the position of the powder non-placement area 6 (the center of the MD of the pair of edges 7, 7 ) is largely shifted toward the upstream side of the MD (towards the upstream end 8a of the image data) compared to the position (appropriate position) of the area 6 in the non-defective 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 81 is defective.
In the image data 82 shown in FIG. 4(c), the position of the non-powder placement area 6 is within the predetermined reference value and is a good product, but the MD length of the area 6 is within the predetermined reference value. It is below the lower limit of the range and is shorter than the MD length (appropriate length) of the region 6 in the non-defective 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 defective.
In the image data 83 shown in FIG. 4(d), contrary to the image data 83, the MD length of the powder non-arrangement area 6 exceeds the upper limit of the predetermined reference value range, and the non-defective product image data 80 It is longer than the MD length (appropriate length) of the region 6. Therefore, the inspection unit 40 determines that the portion of the long strip-shaped composite sheet 4 corresponding to the image data 83 is defective.
In the image data 84 shown in FIG. 4(e), the position of the non-powder placement area 6 and the length of MD are within the predetermined standard value range, indicating a good product, but the powder 3 is present in the area 6. Due to this, the area of the white portion of the region 6 is below the lower limit of the predetermined 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 defective.

In this embodiment, the detection of the edge 7 and the acquisition of its position information are executed by the image processing unit 41, and the quality determination of the dispersion state of the powder 3 based on the position information of the edge 7 is executed by the control unit 42. . That is, in this embodiment, the image processing unit 41 performs preprocessing including binarization processing on the image data acquired by the imaging unit 30, and then processes the preprocessed image data in both scanning directions S1 and S2. The edge 7 is scanned to detect the edge 7, and the positional information (separation distances L1, L2, etc.) of the detected edge 7 is acquired, and the positional information is transmitted to the control unit 42. The control unit 42 determines whether the dispersion state of the powder 3 is good or bad based on the position information transmitted from the image processing unit 41, and displays the determination result on the interface 43.

In this embodiment, as described above, the control unit 42 not only functions as a determination unit that determines whether the state of dispersion of the powder 3 is good or bad, but also performs the function of dispersing the powder 3 by the powder dispersion unit 20 based on the determination result. It also has the function of controlling. That is, in this embodiment, the dispersion of the powder 3 by the powder dispersion section 20 is controlled based on the position information of the edge 7. More specifically, as shown in FIG. 1, the control section 42 and the discharge section 22 of the powder scattering section 20 are electrically connected, and the control section 42 controls the edge 7 obtained from the image data of the inspection target. A control signal for the discharge section 22 is generated based on the position information of and transmitted to the discharge section 22, and the discharge section 22 executes discharge or non-discharge of the powder 3 according to the control signal.

However, the positional information of the edge 7 used in the dispersion of the powder 3 by the powder dispersion unit 20 (powder dispersion process) does not include information determined to be unnecessary in the inspection process by the inspection unit 40 (control unit 42). do not have. For example, the image data 81 described above (see FIG. 4(b)) is determined to be a defective product by the inspection unit 40, so the edge 7 such as the position of the powder non-arrangement area 6 in the image data 81 The position information is not used to generate the control signal sent to the ejector 22. As a result, the accuracy of dispersing the powder 3 by the powder dispersing unit 20 is further improved, so that the non-powder placement area 6 is arranged as designed, and the composite sheet 4 that can stably exhibit a predetermined performance is further stabilized. This makes it possible to manufacture

As described above, the inspection section 40 (control section 42) controls the dispersion of the powder 3 by the powder dispersion section 20 (powder dispersion process) based on the quality determination result of the dispersion state of the powder 3. As an example of the powder dispersion control operation by the inspection unit 40, as shown in image data 81 shown in FIG. An example of this is a return operation that returns the position of the powder non-arrangement area 6 to the proper position when the position of the center of the MD of No. 7 has deviated significantly from the proper position (predetermined reference value).

The graph in FIG. 5 shows an example of the return operation. The upper graph in FIG. 5 shows the relationship between the position (vertical axis) of the powder non-arrangement area 6 in the long strip-shaped composite sheet 4 and the operating time (horizontal axis) of the manufacturing device 10. (Position) indicates the position of the powder non-arrangement area 6 in the coordinate axis of the MD whose origin is the downstream end 8b of the image data 8 to be inspected.
In this example, a position 215 mm away from the origin (downstream end 8b) on the upstream side of the MD is the appropriate position for the powder non-arrangement area 6. On the other hand, the fact revealed as a result of the inspection by the inspection unit 40 is that the position of the powder non-arrangement area 6 at the time of the inspection (the time of image capture by the imaging unit 30) is approximately on the upstream side of the MD from the origin. This means that the amount of deviation from the proper position is approximately 85 mm.
Therefore, the inspection unit 40 (control unit 42) controls the operation of the powder dispersion unit 20, specifically, the discharge/non-discharge of the powder 3 by the discharge unit 22, in order to correct the positional deviation of the powder non-arrangement area 6. The discharging operation is controlled to adjust the dispersion cycle of the powder 3 (return operation). The lower graph in FIG. 5 is a graph showing ON/OFF of the control of the powder dispersion unit 20 by the inspection unit 40, and the range indicated by “returning operation” in FIG. The operation (return operation) of the powder dispersion section 20 (discharge section 22) under the control of is being executed. In this case, the return operation is performed because the powder non-placement area 6 is shifted to the upstream side of the MD (see FIG. 4(b)) from the proper position (see FIG. 4(a)). This is an operation to move the powder to the downstream side of the MD, and specifically, the dispersion cycle of powder 3 is made shorter than the current one (the time interval between one dispersion and the next dispersion is made shorter than the current one). ) is an action. As shown in FIG. 5, as a result of this return operation, the amount of deviation became approximately zero, and the position of the powder non-arrangement area 6 approximately coincided with the proper position. When it is confirmed in the inspection process by the inspection section 40 that the amount of deviation has become substantially zero, the control of the powder dispersion section 20 by the inspection section 40 is turned off, and the return operation is stopped. In this specification, "the amount of deviation is approximately zero" means that the position of the powder non-placement area 6 is determined to be within a predetermined reference value (the reference value is within a certain range) during the inspection process by the inspection unit 40. means that it is within that range).

The manufacturing apparatus 10 has a defective product discharging means (not shown) in the conveyance path of the composite sheet 4, and removes the composite sheet 4 related to the inspection target determined to be a defective product in the inspection process by the inspection unit 40 from the defective product. It may be configured to discharge from the conveyance path (manufacturing line) using a discharge means. In that case, the inspection unit 40 (control unit 42) controls the operation of the defective product discharging means to more accurately determine the quality of the powder 3 and to discharge the defective product from the production line based on the determination result. This can be done smoothly. As the defective product discharging means, any known defective product discharging means in this type of production line can be appropriately used. The defective product discharging means is typically disposed on the downstream side of the MD from a cutting section (not shown) that cuts the long strip-shaped composite sheet 4, and removes single composite sheets 4 that are determined to be defective. discharge.

If the inspection section 40 determines that the product is defective in the inspection process, some kind of recovery operation is performed, including the aforementioned powder dispersion control operation by the inspection section 40 (control section 42) and manual work. This return operation is normally performed until a non-defective product is determined in the inspection process by the inspection section 40. The imaging unit 30 (imaging means The composite sheet 4 that has passed through step 31) is normally treated as a defective product and is to be discharged by the defective product discharging means. Note that each part of the composite sheet 4 to be conveyed, regardless of whether the composite sheet 4 is in the form of a single sheet or a long strip, is placed at a predetermined position on the conveyance path of the composite sheet 4 (for example, at a position where the defective product is discharged by the defective product discharge means). It is possible to specify the separation distance in terms of the number of products (single composite sheets 4) from the product (component), and by using the separation distance, it is possible to distinguish between non-defective products and defective products.

The above has mainly been an explanation regarding the manufacturing apparatus that can be used in the method for manufacturing a composite sheet of the present invention. Below, the method for manufacturing a composite sheet of the present invention will be explained based on the manufacturing method using the above-mentioned manufacturing apparatus 10. do. In the composite sheet manufacturing method described below, the description regarding the above-mentioned manufacturing apparatus 10 applies as appropriate to structures that are not particularly described.

As shown in FIG. 1, the method for manufacturing the composite sheet 4 using the manufacturing apparatus 10 is to intermittently sprinkle powder 3 on the surface 1a of the sheet 1 being conveyed in one direction MD to apply powder to the surface 1a. a powder dispersion step of alternately forming powder placement areas 5 and powder non-placement areas 6 in the one direction MD; and an imaging step of taking an image of the powder scattering surface (surface 1a) of the sheet 1 with an imaging means 31; and an inspection step of inspecting the dispersion state of the powder 3 based on the image data (for example, image data 81 to 84 shown in FIG. 4) acquired in the imaging step.
In the inspection process, the image data is scanned in both MD and anti-MD directions to detect the edge 7 that is the boundary in MD between the powder placement area 5 and the powder non-placement area 6, and to Based on the position information of 7, the quality of the dispersion state of the powder 3 is determined, thereby determining whether the composite sheet 4 is good or defective (see FIG. 3(a)).
By repeatedly performing a series of processes consisting of the imaging process and the inspection process on the inspection target (long strip-shaped composite sheet 4) that is continuously conveyed in one direction MD, the entire inspection target is powdered. It is possible to judge the quality of the dispersion state of the body 3 with high precision, and as a result, it is possible to stably manufacture a composite sheet 4 with guaranteed product performance that can stably exhibit a predetermined performance. Become.

In the inspection step, based on the position information of the edge 7, at least one of the position of the powder non-arrangement region 6, the length and area of the MD may be determined and compared with a predetermined reference value.
The image data to be inspected in the inspection step may be subjected to pre-processing including binarization processing prior to inspection (see FIG. 2(c)).
By repeatedly performing a series of processes consisting of the imaging process and the inspection process on the inspection target (long strip-shaped composite sheet 4) that is continuously conveyed in one direction MD, the entire inspection target is powdered. The quality of the spread state of the sheet 3 can be determined with high precision, and the quality of the composite sheet 4, which is the object of manufacture, can be determined with high precision.
The dispersion of the powder 3 in the powder dispersion step may be controlled based on the position information of the edge 7.
It is preferable that the position information of the edge 7 used in the powder dispersion process does not include information determined to be defective in the inspection process.

The above is mainly a state in which the manufacturing apparatus 10 is in normal operation, that is, the conveying speed of the first sheet 1 on which the powder 3 is spread is maintained at a predetermined target speed (production speed), and the composite sheet as a product is Although the explanation was based on the assumption that the manufacturing apparatus 10 is manufactured continuously, the present invention is capable of performing a series of inspection processes including the above-described imaging process and inspection process after the manufacturing apparatus 10 in a stopped state starts operating. At least one of the period until the normal operation state is reached (manufacturing start-up process), and the period from issuing a stop command to the manufacturing apparatus 10 in normal operation until the manufacturing apparatus 10 completely stops (manufacturing stop process), It is characterized in that it preferably applies to both.

Specifically, in the present invention, the manufacturing start-up process accelerates the conveyance speed of the first sheet 1 from a state where the conveyance of the first sheet 1 is stopped to a predetermined target speed, or the sheet is conveyed at a predetermined target speed. In the production stop step in which the conveyance speed of the sheet 1 is decelerated and the conveyance of the sheet 1 is finally stopped, the position information of the edge 7 described above, specifically, for example, the "separation distances L1, L2" and the "powder non-conveyance" Based on the position of the arrangement region 6, the length and area of MD, The dispersion of the powder 3 in the step of alternately forming powder placement areas 5 and powder non-placement areas 6 in the one direction MD in 1a is controlled.
In this embodiment, by controlling the scattering of the powder 3 based on the positional information of the edge 7, the incidence of defective products in the manufacturing start-up process or the manufacturing stop process is reduced.

FIG. 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 manufacturing start-up process and the manufacturing stoppage process. The vertical axis (Position) in FIG. 6 is the same as the vertical axis in FIG. It is. The "number of products" on the horizontal axis in FIG. ), and the larger the number of products, the farther the inspection target area is from the reference position. The range indicated by the symbol "N" in FIG. 6 is a period during which the manufacturing apparatus 10 is normally operating, that is, a period during which the conveyance speed of the sheet (first sheet 1) is maintained at a predetermined target speed (production speed). shows.

The solid line indicated by the symbol "C0" in FIG. 6 indicates the case where powder dispersion control according to the present invention, that is, "powder dispersion control based on edge position information" is not performed at all (hereinafter also referred to as "conventional manufacturing method"). ) shows the variation in the position of the powder non-arrangement area 6 (the position of the center of MD of the pair of edges 7, 7). Focusing on the conventional manufacturing method, the powder non-placement area 6 exists at a position 170 mm away from the origin upstream of the MD before the manufacturing apparatus 10 starts operating, and the amount of deviation from the appropriate position at this point is is approximately 45 (=215-170) mm. In the manufacturing start-up process from when the manufacturing apparatus 10 starts operating until the sheet conveyance speed reaches a predetermined target speed (speed during normal operation), the amount of deviation decreases as the sheet conveyance speed increases, The amount of deviation became approximately zero when the number of products was approximately 80. In this case, although it depends on how the reference value (threshold value) regarding the position of the powder non-arrangement area 6 is set, if the deviation amount is set to zero as the reference value, 80 products whose deviation amount is not zero The remainder will be discarded as yield loss. In addition, in the manufacturing stop process from when a stop command is issued to the manufacturing equipment 10 during normal operation until the sheet conveyance speed reaches zero, the amount of deviation increases as the sheet conveyance speed decreases immediately after the stop command is issued. Since the number is gradually increasing, depending on the reference value, there is a possibility that all of the products inspected immediately after the stop command is issued may be discarded as a yield loss.

On the other hand, in the present invention, in order to reduce the yield loss in such manufacturing start-up process and manufacturing stop process, the dispersion of the powder 3 by the powder dispersion unit 20 during these processes is inspected by the inspection unit 40. Control is performed based on the position information of the edge 7 acquired in the process. Specifically, for example, with reference to FIG. 6, although the fluctuation in the position of the powder non-arrangement area 6 in the manufacturing start-up process and the manufacturing stop process is currently indicated by a solid line indicated by the symbol "C0" in FIG. On the other hand, a target is set so that the amount of deviation becomes approximately zero, and the discharge/non-discharge operation of the powder 3 by the discharge section 22 is controlled. As a result, the fluctuation becomes like the dotted line indicated by the symbol "C1" in FIG. Here, the "target for which the amount of deviation is approximately zero" (position variation model of the powder non-placement area 6) may be a value of a predetermined appropriate position, or as indicated by the dotted line C1 in FIG. , the position of the powder non-arrangement area 6 may gradually approach the value of the appropriate position. When the positional fluctuation of the powder non-arrangement area 6 becomes as shown by the dotted line C1, in the manufacturing start-up process, the number of products is smaller than that of the conventional manufacturing method (solid line C0), that is, the amount of deviation becomes almost zero in a short time, and A state in which the amount of deviation is approximately zero is maintained during the manufacturing start-up process. In addition, the same tendency as in the production start-up process is observed in the production stop process, and when the fluctuation in the position of the powder non-placement area 6 becomes as indicated by the dotted line C1, there is a relatively long time lag after the issuance of the stop command. The state where the amount is substantially zero is maintained, and the rate of change in the amount of deviation thereafter is gentler than in the conventional manufacturing method. Therefore, since the position of the powder non-arrangement area 6 changes as indicated by the dotted line C1, yield loss in the manufacturing start-up process and the manufacturing stop process is effectively reduced.

In particular, in this embodiment, the powder 3 spread in the powder spreading process is configured to reach the first sheet 1 by free fall (see FIG. 1), but the free fall speed of the powder 3 is constant. On the other hand, during the production start-up process and the production stop process, that is, during acceleration and deceleration of the sheet conveyance speed, the conveyance speed of the first sheet 1 changes at any time, so the position of the powder non-arrangement area 6 also changes at any time. Yield loss is likely to occur. According to the present invention, even in such a case, yield loss can be effectively suppressed.

The positional variation model of the powder non-arrangement area 6, which is the target in the production start-up process or the production stoppage process, is located at a location (for example, the image processing unit 41) that can be read by the inspection unit 40 (control unit 42) that controls powder dispersion. ) may be stored in advance. In that case, for example, in the manufacturing start-up process and the manufacturing stop process, the control unit 42 reads out the positional fluctuation model, and controls the positional information of the edge 7 (specifically, the positional information of the edge 7 obtained from the image data of the inspection target) in the manufacturing start-up process and the manufacturing stoppage process. (positional information of area 6), the difference between the two is ascertained, and the discharge/non-discharge operation of the powder 3 by the discharge section 22 is controlled so as to reduce the difference between the two.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present invention.
In the embodiment, when determining the quality of the dispersion state of the powder 3 on the composite sheet 4, the position information of the edge 7, including the position of the powder non-arrangement area 6, the length and area of the MD, is used as the determination material. However, the basis weight (mass per unit area) of the powder 3 in the powder arrangement region 5 may also be used as a determination material. That is, in the inspection step, the basis weight of the powder 3 in the powder placement area 5 may be inspected, and the inspection unit 40 may inspect the basis weight of the powder 3 in the powder placement area 5. The main items to be inspected in the inspection process that uses the position information of the edge 7 as judgment material are the state of the powder non-placement area 6 (position, MD length, presence or absence of powder 3 in the area 6, etc.). Therefore, by using the basis weight of the powder 3 in the powder placement area 5 as a determination material, the condition of the powder placement area 5 can be inspected, and due to the synergistic effect of these, the It becomes possible to inspect the distribution state of the powder 3 with even higher precision. As a method for inspecting the basis weight of the powder 3, any known method for inspecting the basis weight can be used without particular limitation, and for example, the method described in Patent Document 1 can be used.

In the above embodiment, the composite sheet that is the object of manufacture has a structure in which powder is interposed between two sheets, but it may also be in a structure in which powder is arranged on the surface of one sheet. .
In the embodiment described above, the imaging unit uses a transmitted light illumination method in which transmitted light that is irradiated from the illumination means and transmitted through the inspection object is imaged. A reflected light illumination method that images reflected light may also be used.

10 Manufacturing apparatus 20 Powder spreading section 21 Storage section 22 Discharging section 30 Imaging section 31 Imaging means 32 Illumination means 33 Power source 40 Inspection section 41 Image processing section 42 Control section 43 Interface 1 First sheet 2 Second sheet 3 Powder 4 Composite Sheets 5, 5A, 5B Powder placement area 6 Powder non-placement area 7 Edge

Claims (3)

A method for manufacturing a composite sheet, comprising a sheet and powder disposed on the surface of the sheet,
A powder scattering step of intermittently scattering powder on the surface of a sheet being conveyed in one direction to alternately form powder placement areas and powder non-placement areas on the surface of the sheet; ,
an imaging step of imaging the powder-spreading surface of the sheet with an imaging means;
an inspection step of inspecting the dispersion state of the powder based on the image data acquired in the imaging step,
In the inspection step, the image data is scanned in both the conveyance direction of the sheet and the opposite direction to the conveyance direction to determine the difference between the powder placement area and the powder non-placement area in the conveyance direction. Detecting an edge that is a boundary and determining whether the composite sheet is a good product or a defective product based on the position information of the edge,
A manufacturing start-up process in which the conveyance speed of the sheet is accelerated to a predetermined target speed from a state where the conveyance of the sheet is stopped, or the conveyance speed of the sheet being conveyed at a predetermined target speed is decelerated to finally reach the target speed. In the production stop step of stopping conveyance of the sheet, controlling the dispersion of the powder in the powder dispersion step based on the position information of the edge,
The method for manufacturing a composite sheet, wherein the conveyance direction and the scan in the opposite direction to the conveyance direction each start from the powder placement area and end when the edge is detected. In the inspection step, based on the edge position information, at least one of the position of the powder non-placement area, the length in the transport direction, and the area is determined and compared with a predetermined reference value set in advance. , A method for manufacturing a composite sheet according to claim 1. The composite sheet according to claim 1 or 2, wherein in the powder spreading step, the powder is spread onto the sheet without contacting the sheet, and the spread powder reaches the sheet by free fall. Production method.

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