Automatic control system for skiving quality

Abstract

This system provides an automated control system for skiving quality that enables early detection of abnormal conditions in skiving quality and early recovery to normal conditions. [Solution] The present invention provides an automatic control system for the quality of watermarking, comprising a watermarking image acquisition unit positioned between the calendering unit and the winding unit to acquire an image of the watermarking applied to the paper, and an image determination unit that compares and determines the acquired watermarking image with a preset reference image, and a control unit that controls at least one of the moisture adjustment unit, the wire unit, the watermarking processing unit, and the press unit when it is determined that the watermarking quality is in an abnormal state.

Description

Technical Field

[0001] The present invention relates to an automatic control system for the quality of slits in the production of papers used as securities such as banknotes, stock certificates, bonds, various certificates, and important documents.

Background Art

[0002] Patent Document 1 discloses a slit inspection device that inspects the quality of slits in a paper-making machine and performs a positive / negative determination.

[0003] Patent Document 2 discloses a device that can automatically sample a paper during the papermaking process in order to measure the paper quality (such as the sharpness of the slit pattern and the stretch rate of the paper) and paper characteristics (basis weight, moisture content, and paper thickness) of the wound paper produced in the paper-making machine.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technique described in Patent Document 1 measures the slit quality online, but does not feedback the measured quality results to the paper-making machine for automatic control. Instead, the operator adjusts the slit quality by mechanical operation according to the measurement results, resulting in a time lag in control.

[0006] Also, the technique described in Patent Document 2 evaluates the quality offline. Similar to the technique described in Patent Document 1, the quality is adjusted by the operator based on the measurement results of the slit quality, and does not automatically control the paper-making machine.

[0007] The present invention aims to provide an automatic control system for skiving quality that enables early detection of abnormal conditions in skiving quality and early recovery to a normal condition. [Means for solving the problem]

[0008] The present invention provides an automatic control system for skimming quality used in a wire screen paper machine, which includes: a moisture adjustment unit for adjusting the moisture content of the paper stock; a wire unit for discharging the paper stock to form wet paper; a skimming processing unit for applying skimming to the wet paper; a press unit for applying pressure to the wet paper to dewater it; a drying unit for drying the skimmed wet paper; a calendering unit for adjusting the smoothness and thickness of the dried paper; and a winding unit for winding up the paper that has passed through the calendering unit. The system is further characterized by having a skimming quality determination unit, which is positioned between the calendering unit and the winding unit and includes a skimming image acquisition unit for measuring the quality of the skimming applied to the paper, and an image determination unit for comparing and determining the skimming image acquired by the skimming image acquisition unit with a preset reference image. When the image determination unit determines that the quality is different from a preset reference value, the system has a control unit that controls at least one of the moisture adjustment unit, wire unit, skimming processing unit, and press unit.

[0009] Furthermore, the automatic control system for skiving quality of the present invention is characterized in that the control unit controls the height of the dandy roll installed in the wire section or the skiving processing section.

[0010] Furthermore, the automatic control system for skiving quality of the present invention is characterized in that the control unit controls the press pressure of the press roll installed in the skiving processing section or the pressing section.

[0011] Furthermore, the automatic control system for skiving quality of the present invention is characterized in that the control unit controls the suction force of the suction box installed in the wire section or the skiving processing section. [Effects of the Invention]

[0012] According to the present invention, the device has a skiving quality determination unit which includes a skiving image acquisition unit installed between the calendar unit and the winding unit, and an image determination unit which compares and determines the acquired image with a preset reference image. The skiving quality determination unit determines the skiving quality to be measured, and if it is determined that the value is different from a preset reference value, it controls at least one of the moisture adjustment unit, wire unit, skiving processing unit, and press unit. This enables early detection of abnormal skiving quality conditions and early recovery to normal conditions, making the process efficient and reducing the workload. [Brief explanation of the drawing]

[0013] [Figure 1] Conceptual diagram showing an automatic control system for skiving quality according to this embodiment. [Figure 2] This diagram shows the conceptual structure of the skiving section of the screenwood paper machine used in this embodiment. [Figure 3] This diagram illustrates the concept of the image acquisition unit for the screen printing process used in this embodiment. [Figure 4] Flowchart showing the automatic control system for skiving quality according to this embodiment. [Modes for carrying out the invention]

[0014] The present invention provides an automatic control system for skiving quality, which includes a skiving quality determination unit 11 between the calendering unit 6 and the winding unit 7, comprising a skiving image acquisition unit 11a and an image determination unit 12 for determining the acquired image. When the skiving quality determination unit 11 determines that the skiving quality is in an abnormal state, it controls at least one of the moisture adjustment unit 1, the wire unit 2, the skiving processing unit 3, and the press unit 4. This enables early detection of abnormal skiving quality and early recovery to a normal state, resulting in efficiency and reduced workload.

[0015] In the automatic control system for the quality of the embossing according to the present invention, in the control unit 13, the pressing pressure of the dandy roll installed as an example of the embossing processing unit 3 is controlled. According to the present embodiment, by moving the dandy roll up and down and controlling the pressing pressure, the clarity of the embossing can be adjusted.

[0016] In the automatic control system for the quality of the embossing according to the present invention, in the control unit 13, the pressing pressure of the press roll installed as another example of the embossing processing unit 3 is controlled. According to the present embodiment, by controlling the pressing pressure of the press roll, the clarity of the embossing can be adjusted.

[0017] In the automatic control system for the quality of the embossing according to the present invention, in the control unit 13, the suction force of the suction box installed in the wire part 2 is controlled. According to the present embodiment, by controlling the suction force of the suction box, the moisture of the paper stock can be adjusted, and the clarity of the embossing can be adjusted.

[0018] In the automatic control system for the quality of the embossing according to the present invention, in the control unit 13, the paper stock concentration and the amount of white water in the moisture adjustment unit 1 are controlled. According to the present embodiment, by adjusting the paper stock concentration and the amount of white water in the moisture adjustment unit 1, the clarity of the embossing can be adjusted.

[0019] Hereinafter, the automatic control system for the quality of the embossing according to the embodiment of the present invention will be described.

[0020] FIG. 1 is a conceptual diagram showing the automatic control system for the quality of the embossing according to the present embodiment.

[0021] The automatic control system for the sizing quality is used in a Fourdrinier paper machine comprising a moisture adjusting unit 1 for adjusting the moisture of the paper stock, a wire section 2 for discharging the paper stock to form a wet paper sheet, a sizing processing unit 3 for sizing the wet paper sheet, a press section 4 for applying pressure to the wet paper sheet to dehydrate it, a drying section 5 for drying the sized paper sheet, a calendar section 6 for adjusting the smoothness and paper thickness of the dried paper sheet, and a winding section 7 for winding up the paper sheet 21 that has passed through the calendar section 6.

[0022] The headbox is arranged upstream of the wire 2a. The headbox is supplied with the paper stock and white water and maintains a predetermined liquid level. The paper stock mainly consists of pulp fibers, water, chemicals, sizing agents, etc., and the supply amount of white water and the paper stock concentration are adjusted by the moisture adjusting unit 1.

[0023] In the wire section 2, a sheet-like wet paper sheet is formed while promoting the basis weight balance in the width direction and the dispersion of fibers.

[0024] The paper stock flows from the headbox to the apron and then to the wire 2a that forms a net shape. The wire 2a is stretched between the suction couch roll 2b and the breast roll 2c and is supported by a plurality of table rolls 2d.

[0025] The wire 2a is supported by the table rolls 2d and conveys the paper stock supplied from the headbox while dehydrating it.

[0026] Downstream of the wire 2a, a suction box and a dandy roll 3a are arranged.

[0027] The suction box forcibly sucks and dehydrates the water contained in the wet paper sheet. The dandy roll 3a improves the formation of the wet paper sheet and smoothens the surface of the wet paper sheet.

[0028] The sizing processing unit 3 is arranged downstream of the wire section 2a where the wet paper sheet is formed. In the sizing processing unit 3, sizing such as figures, characters, patterns, etc. is processed.

[0029] This embodiment describes an example in which a Dandy Roll 3a is used as the voiding processing section 3. In this case, in addition to improving the texture and smoothing the surface of the wet paper as described above, the Dandy Roll 3a has irregularities on its surface corresponding to the voiding pattern, thereby enabling voiding by the Dandy Roll 3a.

[0030] In the press section 4, the wet paper is dewatered by applying pressure using at least one pair of press rolls 4a and 4b.

[0031] In the drying section 5, the pre-dryer-5A and after-dryer-5B dry the dewatered wet paper and adjust the expansion and contraction behavior of the paper 21.

[0032] The pre-dryer-5A is composed of multiple dry cylinders-5a.

[0033] In the upstream dry cylinder-5a, moisture is removed from the paper 21 at a low temperature to prevent burning and curling, while in the downstream dry cylinder-5a, the paper is dried at a high temperature.

[0034] The after-dryer-5B consists of multiple dry cylinders-5b. In the after-dryer-5B, all dry cylinders-5b are used at approximately the same temperature to dry the paper 21 and adjust the paper moisture content to a target value.

[0035] The coating section 8 is located between the pre-dryer-5A and the after-dryer-5B processes.

[0036] In the coating section 8, the paper 21 is passed between a pair of size rolls 8a and 8b under predetermined pressure, thereby applying a chemical solution to the surface of the paper 21 to reduce paper dust on the paper 21 and improve printability.

[0037] In the calendering section 6, the smoothness of the surface and the thickness of the paper 21 are adjusted by passing the paper 21 between multiple calendering rolls 6a that are subjected to predetermined pressure. The paper 21 that has passed through the calendering rolls 6a is then wound up into the winding section 7.

[0038] The automatic control system for blanking quality according to this embodiment includes a blanking quality determination unit 11 which comprises a blanking image acquisition unit 11a positioned between the calendering unit 6 and the winding unit 7 to acquire a blanking image applied to the paper 21, and an image determination unit 12 that compares the acquired blanking image with a preset reference image to determine the blanking quality. The blanking quality determination unit 11 also includes a control unit 13 that controls at least one of the moisture adjustment unit 1, the wire unit 2, the blanking processing unit 3, and the press unit 4 if it is determined that the determined blanking quality is different from a preset reference value.

[0039] In this invention, skiving quality refers to the clarity of the skiving (skiving clarity).

[0040] Thus, a gap-filling image acquisition unit 11a is provided between the calendar unit 6 and the winding unit 7. When the acquired gap-filling image is determined to be abnormal by the gap-filling quality determination unit 11, at least one of the moisture adjustment unit 1, wire unit 2, gap-filling processing unit 3, and press unit 4 is controlled. This enables early detection of abnormal gap-filling quality and early recovery to a normal state, resulting in efficiency and reduced workload.

[0041] In the skiving quality determination unit 11, the skiving image acquisition unit 11a acquires skiving images at predetermined timings, and the acquired skiving image data is input to the image determination unit 12. Depending on the determination result in the image determination unit 12, control signals are transmitted from the control unit 13 to the moisture adjustment unit 1, the wire unit 2, the skiving processing unit 3, and the press unit 4.

[0042] In this way, by performing control in the control unit 13 online, rapid automatic control of the wire screen paper machine can be achieved.

[0043] For example, the control unit 13 adjusts the paper stock concentration and the amount of white water in the moisture adjustment unit 1, controls the press pressure by moving the dandy roll 3a, which is installed as the skiving processing unit 3, up and down, and controls the suction force of the suction box installed in the wire unit 2.

[0044] In this way, the clarity of the pulp can be adjusted by controlling the press pressure of the Dandy Roll 3a, the moisture content of the pulp can be adjusted by controlling the suction force of the suction box, and the clarity of the pulp can be adjusted by adjusting the pulp concentration and the amount of white water.

[0045] Furthermore, in the suction box, the amount of moisture can be reduced by increasing the suction force, and in the press rolls 4a and 4b installed in the press section 4, the amount of moisture can be reduced by increasing the press pressure.

[0046] In the image determination unit 12 of this embodiment described above, an example was given in which the image determination unit 12 determines whether the gape quality is normal or abnormal. However, even if the acquired gape image is within the normal range (within product specifications), the control unit 13 may determine whether it is trending towards the upper limit (bright gape image) or the lower limit (dark gape image) of the reference value, and based on the result, control each part may be controlled to bring it closer to the reference value.

[0047] Figure 2 is a diagram illustrating the conceptual structure of the skiving section of the long-screen paper machine used in this embodiment.

[0048] Figure 2(a) shows the state in which the dandy roll 3a for shaping is positioned relative to the wire 2a, and Figure 2(b) shows the dandy roll 3a for shaping and the mechanism for controlling the press pressure by moving the dandy roll 3a up and down.

[0049] The wet paper 20 is transported by wire 2a while being dewatered. Downstream of wire 2a, a dandy roll 3a for shaping is positioned. The dandy roll 3a for shaping is supported by a mechanism 14 that controls the press pressure by moving the dandy roll 3a up and down.

[0050] The mechanism 14, which controls the press pressure by moving the Dandy Roll 3a up and down, can change the axial height of the Dandy Roll 3a relative to the wire 2a.

[0051] The mechanism 14 controls the press pressure by moving the Dandy Roll 3a up and down, thereby lowering the axial height of the Dandy Roll 3a, that is, bringing the Dandy Roll 3a closer to the wire 2a, which makes the gape more pronounced.

[0052] Figure 3 is a diagram illustrating the concept of the skiving image acquisition unit 11a, which is part of the skiving quality determination unit 11 of the long-screen paper machine used in this embodiment.

[0053] Figure 3(a) shows the arrangement of the void image acquisition unit 11a, and Figure 3(b) shows the conceptual configuration of the void image acquisition unit 11a.

[0054] The watermark image acquisition unit 11a acquires an image of the watermark on the paper 21 before it is wound onto the winding unit 7.

[0055] The watermark image acquisition unit 11a consists of a light-emitting unit 11b and an imaging unit 11c. The light-emitting unit 11b is positioned on one side of the paper 21, and the imaging unit 11c is positioned on the other side of the paper 21.

[0056] The light-emitting unit 11b illuminates the paper 21 with light, and the imaging unit 11c captures images of the paper 21's watermark.

[0057] Figure 4 is a flowchart showing the automatic control system for skiving quality according to this embodiment.

[0058] In this embodiment of the automatic control system for voiding quality, when a voiding image captured by the imaging unit 11c is input to the image determination unit 12 (S31), the image determination unit 12 performs pattern matching between the reference image in the reference image database 10 and the input image, and calculates the match rate between the reference image and the input image (S32).

[0059] For example, the most appropriate image is designated as the "standard image" as a reference image. Images that are within the product specifications but tend to be brighter than the standard are designated as the "upper limit image," and images that tend to be darker are designated as the "lower limit image." Pattern matching is performed with the images acquired by the image acquisition unit 11a, and the image determination unit 12 determines the image with the highest match rate.

[0060] As a result, the cutout quality determination unit 11 determines that if the acquired cutout image is close to the "upper limit image" determined by the image determination unit 12, it is judged as "overly sharp," and if it is close to the "lower limit image," it is judged as "unclear."

[0061] As described above, the skiving quality measurement unit 11 determines whether the skiving quality is within the normal range (or whether it is closer to the standard image, upper limit image, or lower limit image) based on the match rate (S33).

[0062] If the judgment result from the skiving quality judgment unit 11 is within the normal range or near the standard value, the current settings in the moisture adjustment unit 1, wire unit 2, skiving processing unit 3, and press unit 4 are maintained (S34).

[0063] In S33, if the judgment result from the skiving quality judgment unit 11 is outside the normal range, it is determined to be an abnormal state, and depending on whether the skiving clarity is too clear or unclear (S35), the current setting in at least one of the moisture adjustment unit 1, wire unit 2, skiving processing unit 3, and press unit 4 is changed.

[0064] In S35, if the shading is too sharp, the dandy roll 3a for shading is raised (S36), and if the shading is not sharp, the dandy roll 3a for shading is lowered (S37).

[0065] After changing the settings in S36 or S37, the system waits for a predetermined time (S38), that is, waits until the watermark image after these setting changes can be obtained, before inputting the watermark image in S31.

[0066] In the present invention, the determination of the skiving quality by the skiving quality determination unit 11 is not limited to the examples, and the quality may be determined by performing statistical calculations, such as the average transmittance (average value of brightness) or the maximum transmitted light amount (maximum value of brightness) of the acquired image.

[0067] Alternatively, the determination method may involve setting a control threshold and determining whether a value is normal or abnormal based on whether it exceeds the upper or lower range of the threshold.

[0068] The control standards can be set based on product specifications, or they can be set within a narrower range than the product specifications. The latter is preferable because it allows for adjustments to be made in advance before defective products occur.

[0069] Furthermore, although this embodiment describes an example in which a Dandy Roll 3a is arranged as the skiving section 3, a configuration in which a press roll (not shown) with irregularities corresponding to the skiving pattern is arranged downstream of the press rolls 4a and 4b, and skiving is performed using this press roll.

[0070] In this configuration, when adjusting the pore quality, the control unit 13 may perform moisture adjustment using the press rolls 4a and 4b in addition to the moisture adjustment using the moisture adjustment unit 1 and suction box described above.

[0071] In that case, when controlling the press pressure of the press rolls 4a and 4b, similar to the Dandy roll 3a for shaping in S36 and S37, adjustments may be made such that the moisture content is increased by lowering the press pressure in S36 and decreased by increasing the press pressure in S37. Similarly, when controlling the suction force of the suction box, adjustments may be made such that the moisture content is increased by lowering the suction force in S36 and decreased by increasing the suction force in S37. [Explanation of Symbols]

[0072] 1 Moisture adjustment section 2 Wire section 2a Wire 2b Suction Coot Roll 2c Breastroll 2D Table Roll 3. Cut-off section 3a Dandyroll 4 Press Department 4a, 4b Press Roll 5 Drying section 5a, 5b Dry Cylinder 5A Pre-Dryer 5B After-Dryer 6. Calendar section 6a Calendar Roll 7. Winding section 8. Application area 8a, 8b size rolls 10 Reference Image Database 11. Skimming Quality Judgment Section 11a Image acquisition unit 11b Light-emitting section 11c Imaging Unit 12 Image determination unit 13 Control Unit 14. A mechanism that controls press pressure by moving the Dandy Roll up and down. 21 sheets

Claims

[Claim 1] An automatic control system for skimming quality used in a wire screen paper machine, comprising: a moisture adjustment unit for adjusting the moisture content of the paper stock; a wire unit for discharging the paper stock to form wet paper; a skimming unit for skimming the wet paper; a press unit for applying pressure to the wet paper to dewater it; a drying unit for drying the skimmed wet paper; a calendering unit for adjusting the smoothness and thickness of the paper formed by drying the wet paper; and a winding unit for winding up the paper that has passed through the calendering unit, wherein A watermark quality determination unit comprising: a watermark image acquisition unit disposed between the calendar unit and the winding unit for acquiring an image of the watermark applied to the paper; and an image determination unit for comparing and determining the watermark image acquired by the watermark image acquisition unit with a preset reference image; A control unit controls at least one of the moisture adjustment unit, the wire unit, the skiving processing unit, and the press unit based on the skiving quality result determined by the skiving quality determination unit, An automatic control system for skiving quality, characterized by having [a certain feature].

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