Sheet production apparatus and sheet production method of sheet production apparatus

Abstract

To solve the problem that a cutout amount may deviate from a target value.SOLUTION: A sheet production apparatus includes a tank that accumulates paper pieces, a motor, a blade that is provided in the tank and rotates by a force of the motor, a tube that takes in the paper pieces transported to the outside by rotation of the blade, a transport path that transports the paper pieces from the tube, a production mechanism that produces a sheet by defibrating the transported paper pieces, a measuring instrument that measures an amount of the paper pieces from the tube, and a processor that corrects a next operation of the tube based on the amount of the paper pieces and corrects an operation of the motor based on a moving average value of the amount of the paper pieces so as to reduce a difference between the amount of the paper pieces measured by the measuring instrument and a target value.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a sheet production apparatus and a sheet production method for the sheet production apparatus. [Background technology]

[0002] Conventionally, as shown in Patent Document 1, a waste paper processing device is known in which shredded paper material is dispersed in a dispersion cyclone, weighed in a metering section from a discharge cyclone, and then fed into a pulper tank of a pulper device for producing recycled paper using a wet method. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-7246 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a risk that the paper material fed as coarsely crushed pieces may deviate from the target value. [Means for solving the problem]

[0005] The sheet production device comprises a tank for accumulating paper pieces, a motor, blades located within the tank and rotated by the power of the motor, a tube for taking in the paper pieces transported outward by the rotation of the blades, a transport path for transporting the paper pieces from the tube, a production mechanism for defibrating the transported paper pieces to produce sheets, a measuring device for measuring the amount of paper pieces from the tube, and a processor for correcting the next operation of the tube based on the amount of paper pieces so as to reduce the difference between the amount of paper pieces measured by the measuring device and a target value, and for correcting the operation of the motor based on a moving average value of the amount of paper pieces.

[0006] A sheet production method for a sheet production device comprising a tank for accumulating paper scraps, a motor, blades provided within the tank that rotate by the power of the motor, a tube that takes in the paper scraps transported outward by the rotation of the blades, a transport path for transporting the paper scraps from the tube, a production mechanism that defibrates the transported paper scraps to produce sheets, and a measuring instrument that measures the amount of paper scraps from the tube, wherein the next operation of the tube is corrected based on the amount of paper scraps so as to reduce the difference between the amount of paper scraps measured by the measuring instrument and a target value, and the operation of the motor is corrected based on a moving average value of the amount of paper scraps. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic diagram showing the configuration of a sheet production apparatus. [Figure 2] FIG. 2 is a cross-sectional side view showing an example of a coarse fragment supplying device. [Figure 3] FIG. 2 is a cross-sectional view showing an example of a coarse fragment supplying device as viewed from above. [Figure 4] 10 is a flowchart showing a coarse fragment supplying step. [Figure 5] FIG. 10 is a cross-sectional view showing another example of a coarse fragment supplying device as viewed from above. DETAILED DESCRIPTION OF THE INVENTION

[0008] 1. Production mechanism of seat production device and seat production method A production mechanism and a sheet production method of a sheet production apparatus 100 according to an embodiment will be described with reference to Fig. 1. Directions in each drawing, including Fig. 1, will be described using a three-dimensional coordinate system. For convenience of description, the positive direction of the Z axis will be referred to as the upward direction or simply "up," and the negative direction will be referred to as the downward direction or simply "down," the positive direction of the X axis will be referred to as the rightward direction or simply "right," and the negative direction will be referred to as the leftward direction or simply "left," and the positive direction of the Y axis will be referred to as the backward direction or simply "backward," and the negative direction will be referred to as the forward direction or simply "front."

[0009] As shown in FIG. 1, the sheet production apparatus 100 is an apparatus for producing a sheet S, which is an example of a fibrous structure, from a raw material M1 in a so-called dry manner. In the embodiment, the term "dry process" refers to the process of producing the sheet S from the raw material M1 not in a liquid but in air such as the atmosphere. The sheet production apparatus 100 is not limited to a dry process, and may be a so-called wet process. In the sheet production apparatus 100, the raw material M1 moves from upstream to downstream along the direction of the arrow shown in FIG.

[0010] 1, the sheet producing apparatus 100 includes, from upstream to downstream, a raw material supply unit 11, a crushing unit 12, a crushed fragment supply device 3, a defibrating device 13, a sorting unit 14, a first web forming unit 15, a dividing unit 16, a mixing unit 17, a dispersing unit 18, a second web forming unit 19, a shaping unit 20, a cutting unit 21, and a stock unit 22. The sheet producing apparatus 100 also includes a control unit 281 that controls these units. The sheet producing apparatus 100 also includes a humidifying unit 231, a humidifying unit 232, a humidifying unit 233, a humidifying unit 234, a humidifying unit 235, a humidifying unit 236, and a humidifying unit 237. The sheet producing apparatus 100 also includes a blower 261, a blower 262, a blower 263, and a collecting unit 27. Hereinafter, these components that produce the sheet S from the raw material M1 will be referred to as the production mechanism of the sheet production apparatus 100.

[0011] The control unit 281 (to be described later) included in the sheet production apparatus 100 executes a sheet production method including the following steps for producing a sheet S from the raw material M1 using a production mechanism. Specifically, the control unit 281 controls each component of the production mechanism to execute the following processes in this order: raw material supply process, crushing process, crushed piece supply process, defibrating process, sorting process, first web formation process, dividing process, mixing process, loosening process, second web formation process, sheet formation process, and cutting process. The processes are also called processes. Below, we will explain the production method including each component of the production mechanism in the sheet production apparatus 100 and each process executed by the control unit 281. For the sake of simplicity, the following explanation will omit the execution of each process by the control unit 281.

[0012] The raw material supply unit 11 is a component that performs a raw material supply step of supplying raw material M1 to the crushing unit 12. This raw material M1 is, for example, a fiber-containing material containing cellulose fiber. In the following description, the raw material M1 will be described as an example of recycled paper.

[0013] The crushing unit 12 is a component that performs a crushing step of crushing the raw material M1 supplied from the raw material supply unit 11 in air, such as the atmosphere. The crushing unit 12 has a pair of crushing blades 121 and a chute 122. The pair of crushing blades 121 rotate in opposite directions to crush the raw material M1 between them into crushed pieces M21, which are paper pieces. The shape and size of the coarsely crushed pieces M21 are preferably suitable for the defibration process in the downstream defibration device 13.

[0014] The chute 122 is disposed below the pair of crushing blades 121 and is, for example, conical or funnel-shaped, so that the chute 122 can receive the coarsely crushed pieces M21 that have been crushed by the crushing blades 121 and dropped. Above the chute 122, a humidifying section 231 is disposed adjacent to the pair of coarse crushing blades 121. The humidifying section 231 humidifies the coarsely crushed pieces M21 inside the chute 122. This humidifying section 231 is composed of an evaporative humidifier that generates humidified air. By supplying humidified air to the coarsely crushed pieces M21, it is possible to prevent the coarsely crushed pieces M21 from adhering to the chute 122, etc. due to electrostatic force.

[0015] The chute 122 is connected to the coarse fragment supplying device 3 via a pipe 240. The coarse fragments M21 collected by the chute 122 are sent to the coarse fragment supplying device 3 via the pipe 240 and temporarily stored therein. The coarse fragment supplying device 3 performs a coarse fragment supplying step, humidifying the coarse fragments M21 and turning them into conveying fragments M22, which are a predetermined amount of coarse fragments M21, and supplying them to the defibration device 13. The coarse fragment supplying device 3 will be described in detail later.

[0016] As shown in FIG. 1, the defibrator 13 is a component that performs the defibration process of defibrating the conveying pieces M22 in the air, i.e., in a dry manner. This defibrator 13 can produce defibrated material M3 from the conveying pieces M22 introduced from the pipe 241. Here, "defibrating" refers to untangling the conveying pieces M22, which are made up of multiple fibers bonded together, into individual fibers. This untangled material becomes the defibrated material M3. The shape of the defibrated material M3 is linear or strip-like. Furthermore, the defibrated material M3 may exist in a state where it is entangled with other defibrated materials and forms clumps, that is, in a state where it forms so-called "lumps."

[0017] The defibrator 13 also has a rotor (not shown). In addition to the blower 261 described below, the defibrator 13 can generate an airflow from the coarse fragment supplying device 3 toward the defibrator 13 by rotation of this rotor. This airflow can introduce the transport pieces M22 from the coarse fragment supplying device 3 into the defibrator 13 via the pipe 241.

[0018] A pipe 242 is connected to the downstream side of the defibrator 13. A blower 261, which is constituted by, for example, a turbo fan, is installed midway along the pipe 242. The blower 261 is an airflow generating device that generates an airflow heading toward the sorting unit 14. The blower 261 promotes the introduction of the conveying pieces M22 into the defibrator 13 and the sending out of the defibrated material M3 to the sorting section 14. The blower 261 also promotes the passage of the conveying pieces M22 within the defibrator 13 and the defibration process. The blower 261 may be arranged downstream of the coarse fragment supply device 3 and upstream of the defibrator 13.

[0019] The sorting unit 14 is a component that performs a sorting process to sort the defibrated material M3 according to fiber length. In the sorting unit 14, the defibrated material M3 is sorted into a first sorted material M4-1 and a second sorted material M4-2 having a fiber length longer than that of the first sorted material M4-1. The first sorted material M4-1 has a size suitable for producing a sheet S. On the other hand, the second sorted material M4-2 has a size that is not suitable for producing a sheet S. In addition, the second sorted material M4-2 includes material that is insufficiently defibrated and material in which defibrated fibers have excessively aggregated together.

[0020] The sorting unit 14 has a drum unit 141 and a housing unit 142 that houses the drum unit 141. The drum unit 141 is a sieve that is made up of a cylindrical mesh body and rotates around its central axis. The defibrated material M3 flows from the pipe 242 toward the inside of the drum section 141. Then, as the drum section 141 rotates, the defibrated material M3 that is smaller than the mesh opening passes from the inside to the outside of the drum section 141 and is sorted as the first sorted material M4-1. Then, the first sorted material M4-1 passes through the drum section 141 and falls into the first web forming section 15.

[0021] On the other hand, defibrated material M3 having a size larger than the mesh opening cannot pass from the inside to the outside of the drum section 141 and is sorted as second sorted material M4-2. The second sorted material M4-2 is sent out to a pipe 243 that communicates with the inside of the drum section 141. Pipe 243 is connected to pipe 241. The second sorted material M4-2 is sent out again to pipe 241 via pipe 243 and merges with the above-mentioned conveying piece M22. The second sorted material M4-2 flows into the defibration device 13 again. In this way, the second sorted material M4-2 is returned to the defibration device 13 and the defibration process is carried out again.

[0022] The first sorted material M4-1 disperses into the air from the drum unit 141 and falls into the first web forming unit 15 located below the drum unit 141. The first web forming unit 15 is a component that performs the first web forming step of forming a first web M5 from the first sorted material M4-1. The first web forming unit 15 has a mesh belt 151 with a mesh, three tension rollers 152, and a suction unit 153. An endless mesh belt 151 is stretched over three tension rollers 152. The mesh belt 151 rotates clockwise as the tension rollers 152 are rotated. The first sorted material M4-1 that has fallen is piled up on the rotating mesh belt 151 and is transported downstream.

[0023] The size of the first sorted material M4-1 is larger than the mesh size of the mesh belt 151. As a result, the first sorted material M4-1 is restricted from passing through the mesh of the mesh belt 151, and is deposited on the mesh belt 151 to be formed as a web-shaped first web M5. The first sorted material M4-1 may contain dust, dirt, etc. The dust, dirt, etc. are generated by, for example, crushing or defibrating the material. Such dust, dirt, etc. are collected by the collection unit 27, which will be described later.

[0024] The suction unit 153 is a suction mechanism that sucks air from below the mesh belt 151. The suction unit 153 sucks the first sorted material M4-1 falling through the air toward the mesh belt 151, promoting deposition. The suction unit 153 also sucks in dust and dirt that has passed through the mesh belt 151 together with the air, and sends it out to the pipe 244. A pipe 244 is connected to the upstream side of the collection unit 27, and a pipe 245 is connected to the downstream side. A blower 262 is installed midway along the pipe 245. This blower 262 generates the suction force of the suction unit 153. The dust and dirt sent to the pipe 244 is collected by the collection unit 27.

[0025] The housing part 142 of the sorting unit 14 is connected to the humidifying part 232. The humidifying part 232 is configured with an evaporative humidifier. As a result, humidified air is supplied into the housing part 142. This humidified air can humidify the defibrated material M3, and can also prevent the defibrated material M3 from adhering to the inner wall of the housing part 142 due to electrostatic force.

[0026] Furthermore, a humidifying unit 235 is disposed above the mesh belt 151 on the downstream side of the first web forming unit 15. The humidifying unit 235 is configured with an ultrasonic humidifier that sprays water. The humidifying unit 235 can supply moisture to the first web M5 and adjust the moisture content of the first web M5. This adjustment can suppress adhesion of the first web M5 to the mesh belt 151 due to electrostatic force. As a result, the first web M5 can be easily peeled off from the mesh belt 151 at the position where the rotating mesh belt 151 is folded back by the tension roller 152.

[0027] A segmentation unit 16 is disposed downstream of the first web forming unit 15. The segmentation unit 16 is a component that performs a segmentation process to segment the first web M5 peeled from the mesh belt 151. The segmentation unit 16 has a rotatably supported propeller 161 and a housing unit 162 that houses the propeller 161. The rotating propeller 161 can segment the first web M5 into segments of a predetermined length. The first web M5 is segmented into segments M6. The segments M6 descend within the housing unit 162. The housing 162 is connected to the humidifier 233. The humidifier 233 is configured as an evaporative humidifier. This allows humidified air to be supplied to the fragmented bodies M6 inside the housing 162. This humidified air can also prevent the fragmented bodies M6 from adhering to the propeller 161 or the inner wall of the housing 162 due to electrostatic force.

[0028] A mixing section 17 is disposed downstream of the dividing section 16. The mixing section 17 is a component that performs a mixing step of mixing the divided bodies M6 with an additive. The mixing section 17 includes an additive supply section 171, a pipe 172, and a blower 173. The pipe 172 connects the housing 162 of the subdivision section 16 and the housing 182 of the dispersion section 18, and is a flow path through which the mixture M7 of the subdivision bodies M6 and the additive passes.

[0029] An additive supply unit 171 and a blower 173 are connected to the middle of the pipe 172. The additive supply unit 171 has a housing unit 170 in which an additive is accommodated, and an additive screw feeder 174 provided in the housing unit 170. By the rotation of the additive screw feeder 174, the additive in the housing unit 170 is pushed out of the housing unit 170 and supplied into the pipe 172. The additive supplied into the pipe 172 is mixed with the smashed bodies M6 that have moved from the smashing unit 16 to the pipe 172, to form a mixture M7.

[0030] Here, examples of additives supplied from the additive supply unit 171 include a binder that binds fibers together, a colorant that colors the fibers, an aggregation inhibitor that inhibits aggregation of fibers, a flame retardant that makes fibers less flammable, and a paper strength enhancer that enhances the paper strength of the sheet S, and one or more of these can be used in combination. Below, as an example, a case where the additive is a binder P1 will be described. When the additive contains a binder that binds fibers together, the strength of the sheet S can be increased.

[0031] A blower 173 is installed in the pipe 172 downstream of the additive supply unit 171. The action of a rotating part such as a blade of the blower 173 promotes mixing of the pulverized materials M6 and the binder P1. The blower 173 can also generate an airflow toward the dispersion unit 18. This airflow can also agitate the pulverized materials M6 and the binder P1 within the pipe 172. As a result, the mixture M7 is transported to the dispersion unit 18 in a state in which the pulverized materials M6 and the binder P1 are uniformly dispersed. Furthermore, the pulverized materials M6 in the mixture M7 are loosened as they pass through the pipe 172, becoming finer fibers.

[0032] The dispersion unit 18 is a component that performs a disentangling process of disentangling and releasing entangled fibers in the mixture M7. The dispersion unit 18 has a drum 181 that introduces and releases the defibrated mixture M7, and a housing 182 that houses the drum 181. The drum 181 is a sieve made of a cylindrical mesh body that rotates around its central axis. The mixture M7 is introduced into the inside of the drum 181 from the pipe 172. As the drum 181 rotates, fibers and other particles of the mixture M7 that are smaller than the mesh openings can pass from the inside to the outside of the drum 181. At that time, the mixture M7 is loosened and released together with air. In other words, the drum 181 functions as a release section that releases the material containing fibers.

[0033] Housing 182 is connected to humidifier 234. Humidifier 234 is configured as an evaporative humidifier. Humidifier 234 supplies humidified air into housing 182. This humidified air can humidify mixture M7 inside housing 182 and can also prevent mixture M7 from adhering to the inner wall of housing 182 due to electrostatic force.

[0034] The mixture M7 released from the drum 181 disperses in the air and falls into the second web forming unit 19 located below the drum 181. The second web forming unit 19 is a component that performs the second web forming step of depositing the mixture M7 to form a second web M8, which is a deposit. The second web forming unit 19 has a mesh belt 191, a tension roller 192, and a suction unit 193.

[0035] The mesh belt 191 is a mesh member having a mesh pattern and is configured as an endless belt. The mesh belt 191 is stretched over four tension rollers 192. The mesh belt 191 rotates clockwise as the tension rollers 192 are rotated. The mixture M7 is piled up on the rotating mesh belt 191 and transported downstream. In the illustrated configuration, the mesh belt 191 is used as an example of the mesh member, but the present invention is not limited to this, and for example, a flat plate-shaped member may also be used.

[0036] Most of the mixture M7 on the mesh belt 191 has a size equal to or larger than the mesh openings of the mesh belt 191. This restricts the mixture M7 from passing through the mesh openings of the mesh belt 191, allowing it to accumulate on the mesh belt 191. The mixture M7 also accumulates on the rotating mesh belt 191 and is formed as a second web M8 in a web shape.

[0037] The suction unit 193 is a suction mechanism that sucks air from below the mesh belt 191. The suction unit 193 can suck the mixture M7 falling through the air toward the mesh belt 191, accelerating the deposition of the mixture M7 on the mesh belt 191. A pipe 246 is connected to the suction unit 193. A blower 263 is installed in the pipe 246. The blower 263 generates a suction force in the suction unit 193.

[0038] The humidifying section 236 is disposed downstream of the dispersing section 18. The humidifying section 236 is configured with an ultrasonic humidifier, similar to the humidifying section 235. The humidifying section 236 can supply moisture to the second web M8 and adjust the moisture content of the second web M8. This adjustment can suppress adhesion of the second web M8 to the mesh belt 191 due to electrostatic force. As a result, the second web M8 is easily peeled off from the mesh belt 191 at the position where the mesh belt 191 is folded back by the tension roller 192.

[0039] A forming unit 20 is disposed downstream of the second web forming unit 19. The forming unit 20 is a component that performs a sheet forming step of forming a sheet S from the second web M8. The forming unit 20 includes a pressurizing unit 201 and a heating unit 202.

[0040] The pressure applying unit 201 has a pair of calender rollers 203, and can apply pressure to the second web M8 between the calender rollers 203 without heating it. This increases the density of the second web M8. The second web M8 is then transported toward the heating unit 202. One of the pair of calender rollers 203 is a driven roller driven by the operation of a motor (not shown), and the other is a driven roller.

[0041] The heating section 202 has a pair of heating rollers 204, and can apply pressure to the second web M8 while heating it between the heating rollers 204. This heating and pressurizing melts the binder P1 in the second web M8, and the fibers are bound together by the molten binder P1. The second web M8 is then transported toward the cutting section 21. One of the pair of heating rollers 204 is a drive roller driven by the operation of a motor (not shown), and the other is a driven roller.

[0042] The cutting unit 21 is disposed downstream of the forming unit 20. The cutting unit 21 is a component that performs a cutting step of cutting the second web M8. The cutting unit 21 has a first cutter 211 and a second cutter 212. The first cutter 211 cuts the second web M8 in a direction intersecting the transport direction of the second web M8, particularly in a direction perpendicular to the transport direction of the second web M8. The second cutter 212 cuts the second web M8 in a direction parallel to the conveyance direction of the second web M8 downstream of the first cutter 211. This cutting removes unnecessary portions from both side edges of the second web M8 in the width direction, thereby adjusting the width of the second web M8.

[0043] A sheet S having a desired shape and size is obtained by cutting with the first cutter 211 and the second cutter 212. Then, this sheet S is conveyed further downstream and accumulated in the stock unit 22.

[0044] 1, the sheet producing apparatus 100 includes a control board 28. The control board 28 includes a control unit 281 and a storage unit 282. The control unit 281 comprehensively controls each component part of the sheet production apparatus 100 and executes each process. The control unit 281 is configured to include a CPU (Central Processing Unit), a UART (Universal Asynchronous Receiver Transmitter) that manages input and output, and a processor such as an FPGA (Field Programmable Gate Array) or PLD (Programmable Logic Device) that is a logic circuit.

[0045] The storage unit 282 is configured to include memories such as a flash ROM (Read Only Memory), which is a rewritable nonvolatile memory, an HDD (Hard Disk Drive), and a RAM (Random Access Memory), which is a volatile memory. Note that the storage unit 282 also stores calculation formulas used by the CPU of the control unit 281 for control, etc., which will be described later, the rotation speeds of various motors, their initial values, correction values, threshold values, and the like. The CPU of the control unit 281 reads out programs and the like stored in the nonvolatile memory of the storage unit 282, and executes them using the RAM of the storage unit 282 as a work area.

[0046] 2. Example of the configuration of a coarse fragment supply device An example of the configuration of the coarse fragment supplying device 3 according to the embodiment will be described with reference to Figures 2 and 3. Figures 2 and 3 show an example of a coarse fragment supplying device 3 equipped with a single cylinder, a screw feeder 6. Note that Figure 5, which will be described later, shows another example of the coarse fragment supplying device 3, a coarse fragment supplying device 3A equipped with two cylinders, a first screw feeder 6A and a second screw feeder 6B. Furthermore, hereinafter, the screw feeder will be referred to simply as a feeder, such as the screw feeder 6 being referred to as a feeder 6.

[0047] As shown in Figure 2, the coarse fragment supply device 3 includes a tank 4 for accumulating coarse fragments M21, which are pieces of paper introduced from an upper pipe 240, a humidifying section 237 for supplying humidified air WA, an agitating blade 5 for agitating the coarse fragments M21, a feeder 6 which is a tube that takes in the coarse fragments M21 and transports them as a predetermined amount of transported fragments M22, and a measuring instrument 7. The stirring blade 5 is provided at the bottom inside the tank 4 and has a stirring motor 50 , a shaft 51 , a rotating plate 53 , blades 54 , and protrusions 52 . The feeder 6 is provided outside the tank 4 and includes a spiral ribbon-shaped screw 64 , a cylindrical case 61 , and a conveying motor 60 that rotates the case 61 . The measuring instrument 7 includes a load cell 70 , a bucket 71 , and an opening / closing plate 72 .

[0048] The tank 4 is cylindrical overall, with multiple funnel-shaped sections on the inside where the inner diameter decreases downward. Furthermore, the protrusion 52 at the tip of the shaft 51 of the agitator 5 is conical, and protrudes upward from the center of the bottom of the cylinder of the tank 4. The tank 4 and protrusion 52, which have such a shape, allow the coarsely crushed fragments M21 introduced from the upper pipe 240 to gradually descend within the tank 4. This prevents the coarsely crushed fragments M21 from descending all at once and becoming unevenly distributed or clogging within the tank 4.

[0049] The humidifying section 237 is composed of an ultrasonic or vaporization type humidifier. The humidifying section 237 supplies humidified air WA to the coarsely crushed pieces M21 in the tank 4, thereby adjusting the moisture content of the coarsely crushed pieces M21. The coarsely crushed pieces M21 absorb moisture and become soft, making them easier to stir with the stirring blades 5. Furthermore, the coarsely crushed pieces M21 that contain moisture are prevented from sticking to the inside of the tank 4 due to electrostatic force.

[0050] The rotating plate 53 of the stirring blade 5 has a disk shape and is placed at the cylindrical bottom of the tank 4. The center of the disk shape of the rotating plate 53 is connected to a shaft 51, and the shaft 51 is connected to a stirring motor 50. The rotating plate 53 can be rotated around the Z axis by the stirring motor 50 via the shaft 51. The stirring motor 50 can rotate under the control of the control unit 281. The rotating plate 53 is provided with a plurality of blades 54 that extend from the center of the disk shape toward the edges and also extend upward. When the stirring motor 50 rotates, the rotating plate 53 rotates via the shaft 51, and the blades 54 on the rotating plate 53 also rotate.

[0051] 3, the stirring motor 50, shaft 51, rotating plate 53, and blade 54 rotate clockwise when viewed from the Z direction. They may also rotate counterclockwise. The rotating blade 54 stirs the coarsely crushed pieces M21 that accumulate at the bottom of the tank 4. In the following description, the stirring motor 50 will also be simply referred to as a motor. In this manner, the blades 54 of the stirring motor 50 are provided inside the tank 4 and rotated by the power of the motor.

[0052] A portion of the outer peripheral wall at the bottom of the tank 4 is open and is connected to an inlet 62 of the feeder 6. The inlet 62 is provided so as to be positioned at the same height as the blades 54 of the agitating impeller 5. The blades 54 of the agitating impeller 5 can efficiently take in the coarsely crushed fragments M21 into the inlet 62 while agitating the coarsely crushed fragments M21. The coarsely crushed pieces M21 are taken in through the inlet 62 of the feeder 6, transported through the case 61, and discharged through the outlet 63. The case 61 is inclined downward from the inlet 62 to the outlet 63, which facilitates smooth transport of the coarsely crushed pieces M21.

[0053] A conveying screw 64 is provided on the inner wall of the case 61 of the feeder 6. The coarsely crushed pieces M21 taken in from the inlet 62 of the feeder 6 are conveyed within the case 61 toward the outlet 63 by the screw 64, which rotates together with the case 61 by the conveying motor 60. 3, the screw 64 rotates clockwise when viewed from the inlet 62 to the outlet 63 of the feeder 6. Depending on the helical shape of the screw 64, the screw 64 may also rotate counterclockwise. In this way, the feeder 6, which is a cylinder, can take in the coarsely crushed pieces M21 that are transported to the outside of the tank 4 by the rotation of the blades 54 of the stirring blade 5.

[0054] The conveyance motor 60 rotates for a predetermined period of time and then stops. The conveyance motor 60 rotates under the control of the control unit 281. While the conveying motor 60 rotates, the coarsely crushed pieces M21 are conveyed by the screw 64 of the case 61, and a predetermined amount is deposited from the outlet 63 into the bucket 71 of the measuring instrument 7. Hereinafter, the coarsely crushed pieces M21 conveyed by the feeder 6 and deposited in a predetermined amount into the bucket 71, that is, a lump of coarsely crushed pieces M21, will be referred to as a conveyed piece M22. Hereinafter, the act of depositing will also be referred to as opening. The conveyed piece M22 is also the coarsely crushed pieces M21 that have been opened from the feeder 6 into the bucket 71.

[0055] The transported piece M22 thrown into the bucket 71 of the measuring instrument 7 is weighed by the load cell 70. An opening / closing plate 72 that can be opened and closed by an opening / closing motor (not shown) is provided at the bottom of the bucket 71. When the conveying piece M22 is dropped into the bucket 71, the opening / closing plate 72 is closed. After the conveying piece M22 dropped into the bucket 71 is weighed by the load cell 70, the opening / closing plate 72 is opened by the opening / closing motor and the conveying piece M22 falls into the pipe 241.

[0056] The pipe 241 is a transport path for transporting the transport pieces M22 opened from the feeder 6 to the defibrating device 13. In the following, when focusing on the coarse fragment supplying device 3 in the sheet production apparatus 100, the components downstream of the coarse fragment supplying device 3, including the defibrating device 13, will be referred to as the production mechanism. That is, in this case, the production mechanism produces sheets S by defibrating the transported pieces M22 that are transported from the coarse fragment supplying device 3 by the pipe 241 and retain the shape of paper pieces.

[0057] In this way, the coarse fragment supplying device 3 humidifies the coarse fragments M21 introduced into the tank 4 from the crushing section 12 via the pipe 240 by the humidifying section 237. Then, under the control of the control unit 281, the coarse fragment supplying device 3 conveys the coarse fragments M21 by the feeder 6 for a predetermined period while stirring them with the blades 54 of the stirring impeller 5, and then measures them with the measuring instrument 7 and drops them into the pipe 241 as a predetermined amount of conveyed fragments M22. The coarse fragment supplying device 3 can supply the coarse fragments M21 as an appropriate amount of conveyed fragments M22 downstream, including to the defibrator 13.

[0058] 3. Coarse crushed piece supply process using coarse crushed piece supply device An example of control of the coarse fragment supplying process of the coarse fragment supplying device 3 executed by the CPU of the control unit 281 will be described in detail with reference to Figure 4. For simplicity of explanation, the CPU of the control unit 281 will be simply referred to as the CPU below. As mentioned above, the CPU is an example of a processor.

[0059] An operator of the sheet production apparatus 100 operates an input / output unit such as a touch panel (not shown) to instruct the sheet production apparatus 100 to start each process, including the coarse fragment supply process, or the coarse fragment supply device 3 to start the coarse fragment supply process. Based on the instruction, the CPU starts controlling each process by the sheet production apparatus 100, or starts controlling the coarse fragment supplying process by the coarse fragment supplying apparatus 3, starts rotating the stirring motor 50 of the stirring blade 5 at a predetermined rotation speed, and starts rotating the blades 54 (S101). Note that the initial rotation speeds of the stirring motor 50 and the blades 54 are set to initial values. The CPU starts the rotation of the conveyance motor 60 of the feeder 6, and the case 61 starts to rotate (S102).

[0060] The coarsely crushed pieces M21 in the tank 4 are taken in through the inlet 62 of the feeder 6. The taken-in coarsely crushed pieces M21 are transported toward the outlet 63 by a screw 64 that rotates together with the case 61. In this example, the predetermined rotation speeds of the conveying motor 60 of the feeder 6 and the case 61 are constant. The CPU measures the weight of the conveyed piece M22 conveyed by the feeder 6 and thrown into the bucket 71 from the outlet 63 using the measuring instrument 7 (S103).

[0061] The CPU determines whether the measured weight of the conveyed piece M22 exceeds a threshold value (S104). Note that the initial threshold value is an initial value. When the CPU determines that the weight of the conveyed piece M22 exceeds the threshold value (S104: YES), it stops the conveyance motor 60 of the feeder 6 and stops the rotation of the case 61 (S105). Hereinafter, the threshold value used to determine whether to stop the operation is also referred to as the “stop threshold value.” The stop threshold value can also define the timing at which the rotation of the conveyance motor 60 and the case 61 of the feeder 6 is stopped. On the other hand, if the CPU determines that the weight of the conveyed pieces M22 does not exceed the threshold value (S104: NO), it continues to rotate the conveying motor 60 to rotate the case 61 of the feeder 6, convey the coarsely crushed pieces M21, and measure the weight of the conveyed pieces M22 with the measuring instrument 7 (S103). That is, the CPU monitors the weight of the conveyed pieces M22, and when a weight exceeding the stop threshold value is dumped into the bucket 71 from the outlet 63, it stops the conveying motor 60 of the feeder 6 and stops the rotation of the case 61.

[0062] The transportation of the conveyed piece M22 by the feeder 6 is referred to as "cutting out," and the weight of the conveyed piece M22 finally cut out and measured by the measuring instrument 7 after the rotation due to inertia of the case 61 has stopped is referred to as the cut-out amount. The CPU corrects the stop threshold using feedback control so that the actual cut-out amount becomes the target cut-out amount (S106). The CPU can use, for example, PI (Proportional Integral) control, which is a type of feedback control, or P (Proportional) control, which is a proportional control. That is, the CPU corrects the threshold value and feeds it back to determine the cut-out amount of the next conveyed piece M22.

[0063] For example, the CPU can correct the threshold value based on the cutout amount using PI control as follows: Specifically, the CPU can calculate the following equation, where TV is the target value of the cut-out amount, Wn is the n-th cut-out amount, En is the n-th deviation between these, K is the correction coefficient, Kp is the integration coefficient, Cn is the n-th correction value, THn is the n-th threshold, and TH(n+1) is the next threshold after correction. Note that below, the deviation will also be simply referred to as the difference. Here, the number of times is counted, with the period from the start to the end of rotation of the case 61 being considered as one rotation.

[0064] [Number 1] TV-Wn=En …(1) K×En+Kp×Σ(E1+E2+···+En-1+En)=Cn …(2) THn+Cn=TH(n+1) …(3)

[0065] For example, in the first cropping where n is 1, TV, which is the target cropping amount, is 2.0 g, W1, which is the first cropping amount, is 2.1 g, K, which is the correction coefficient, is 1, and TH1, which is the first threshold, is 1.7 g. Note that these are just examples, and other values ​​may be used. The CPU can calculate TH2, which is the next threshold, as 1.6 g, as shown below. In the following formula, only numerical values ​​are shown, and the unit g is omitted.

[0066] Substitute the above values ​​into equation (1). E1=TV-W1=2.0-2.1=-0.1 Substitute the above values ​​into equation (2). C1=K×E1=1×(-0.1)=-0.1 Substitute the above values ​​into equation (3). TH2=TH1+C1=1.7+(-0.1)=1.6

[0067] In this way, for example, when the cut-out amount Wn exceeds the target value TV, the CPU can correct the threshold to be smaller and control to reduce the cut-out amount of the next conveyed piece M22. In the above example, when Wn exceeds TV by 0.1 g, the CPU can reduce the threshold from 1.7 to 1.6 and control to reduce the cut-out amount of the next conveyed piece M22. On the other hand, if the cut-out amount Wn is smaller than the target value TV, the CPU can correct the threshold to be larger and control the cut-out amount of the next cut-out conveyance piece M22 to be conveyed to be larger.

[0068] The CPU can also perform control to correct the operation time of the conveyance motor 60 of the next feeder 6 based on Wn, which is the amount of the conveyed piece M22 measured by the measuring device 7. That is, the CPU can substitute the corrected operation time of the conveyance motor 60 of the next feeder 6 as control using a value other than the weight threshold value. In accordance with the above control, the CPU can also perform feedback control to correct the operating time of the conveyance motor 60 based on the actual dispensed amount and the target dispensed amount instead of the corrected weight threshold.

[0069] In this way, the CPU can also correct the next operation of the feeder 6's conveying motor 60 based on Wn so as to reduce the difference between Wn, which is the amount of conveyed piece M22 measured by the measuring instrument 7, and TV, which is the target value.

[0070] As described above, the coarsely crushed pieces M21 are taken in through the inlet 62 of the feeder 6 while being stirred by the blades 54 of the stirring blade 5 in the tank 4. Therefore, the amount of conveyed pieces M22 cut out by the feeder 6 is also affected by the rotation speed of the blades 54 of the stirring blade 5. Therefore, the CPU also performs feedback control and correction of the rotation speed of the blades 54 of the agitating impeller 5 (S107).

[0071] As a specific example, the CPU corrects the rotation speed of the blades 54 through P control based on the moving average value THA. The moving average value THA is the average value of a predetermined number of corrected threshold values ​​taken as sample values ​​over a certain period of time. This certain period is sequentially shifted in chronological order. For example, the moving average value THA is the average value of a predetermined number of threshold values ​​over the most recent certain period of time. The CPU can calculate the following equation, where THA is the moving average value of the threshold after correction, TH0 is the initial value of the threshold, EA is the deviation between them, KA is the rotation correction coefficient, CA is the correction value, RA is the rotation speed before correction, and R is the next rotation speed after correction. Note that the initial RA uses the initial value of the rotation speed. As a result, the CPU can use P control as shown in equation (5). Note that KA is also called proportional gain.

[0072] [Number 2] EA=THA-TH0 …(4) CA = KA × EA …(5) R = RA + CA …(6)

[0073] For example, for any cutout, THA, which is the moving average value of the threshold after correction, is set to 1.6 g, TH0, which is the initial threshold value, is set to 1.7 g, KA, which is the rotation correction coefficient, is set to 100, and RA, which is the rotation speed before correction, is set to 90 rpm (rotations per minute). Note that these may be other values. The unit of KA is rpm / g. The CPU can calculate R, which is the next rotation speed, as follows, assuming 80 rpm. In the following formula, only numerical values ​​are shown, and units such as g are omitted.

[0074] Substitute the above values ​​into equation (4). EA=THA-TH0=1.6-1.7=-0.1 Substitute the above values ​​into equation (5). CA=KA×EA=100×(-0.1)=-10 Substitute the above values ​​into equation (6). R=RA+CA=90+(-10)=80

[0075] In this way, for example, if THA, which is the moving average value of the corrected threshold value, is smaller than TH0, which is the initial value, the CPU can determine that the cut-out amount of the conveying piece M22 tends to increase. In addition, after the rotation of the case 61 of the feeder 6 stops, coarse crushed pieces M21 are generated which fall from the outlet 63 into the bucket 71 of the measuring instrument 7. The amount of the falling coarse crushed pieces M21 tends to increase with the cut-out amount of the conveyed pieces M22. From these facts, the CPU can determine that there is a tendency for the amount of coarsely crushed fragments M21 taken in from the inlet 62 of the feeder 6 to increase. The CPU attempts to reduce the amount of coarsely crushed fragments M21 taken in, and can control the rotation speed of the blades 54 of the stirring blade 5 to decrease.

[0076] On the other hand, if the moving average value THA of the threshold value after correction is greater than the initial value TH0, the CPU can determine that the amount of conveyed pieces M22 cut out tends to decrease. The CPU can control the rotation speed of the blades 54 of the mixing blade 5 to increase the amount of coarsely crushed pieces M21 taken in from the inlet 62 of the feeder 6. Furthermore, by using the moving average value THA, the CPU can prevent the rotation speed of the blades 54 from changing suddenly.

[0077] The CPU can also perform control using a moving average value of Wn, which is the amount of the conveyed piece M22 measured by the measuring instrument 7. That is, the CPU can also use another variable for control, substituting the moving average value THA of the threshold value with the moving average value Wn, which is the amount of conveyed pieces M22. Here, the stirring motor 50 of the stirring blade 5 is also simply referred to as the motor. In accordance with the above-described control, the CPU can also correct the operation of the stirring motor 50 of the stirring blade 5, which is a motor, based on the moving average value Wn, which is the amount of transported pieces M22 measured by the measuring instrument 7, instead of the moving average value THA of the threshold value. As a result, the CPU can perform feedback control to adjust the amount of coarsely crushed pieces M21 taken in from the inlet 62 of the feeder 6 to an appropriate amount.

[0078] The coarsely crushed pieces M21 introduced into the coarsely crushed piece supplying device 3 vary in basis weight, stiffness, amount of paper dust, etc. depending on the paper type, moisture content, etc. These disturbances, which are fluctuation factors, can sometimes reduce the accuracy of the amount of cut-out pieces M22 to be conveyed by the coarsely crushed piece supplying device 3. As described above, the CPU performs a first feedback control on the threshold value for stopping rotation of the case 61 of the feeder 6. Furthermore, the CPU performs a second feedback control on the rotation speed of the blades 54 of the agitator 5. By performing these two feedback controls, the CPU can respond to a wider range of disturbances in the extrusion amount of the conveying pieces M22. In other words, the CPU can control the extrusion amount so that it converges to the target value TV. In this way, the CPU can ensure the accuracy of the extrusion amount of the conveying pieces M22 from the coarse fragment supplying device 3.

[0079] The types and sizes of the raw material M1 that can be processed by the sheet production apparatus 100 are specified in the specifications. However, if the raw material M1 contains something that is not specified in the specifications, such as a foreign object, the amount of the conveyed pieces M22 cut out by the coarse fragment supplying device 3 may become an abnormal value when the CPU makes a correction. In addition, the amount of the conveyed pieces M22 cut out may become an abnormal value due to the sheet production apparatus 100 being used in a manner that is not specified in the specifications.

[0080] Therefore, the CPU determines whether an error has occurred when making the correction (S108). Specifically, the error may occur when En, the difference between the n-th cut-out amount Wn and the target cut-out amount TV, exceeds a predetermined range, or when an abnormal current is detected on an electric board including the control board 28.

[0081] The CPU can determine an error if En is a large value that exceeds the upper limit of a predetermined range, or if Wn is a small value that exceeds the lower limit of a predetermined range. The CPU can also determine an error if Wn does not reach the TV even after a sufficient amount of time has passed.

[0082] In this case, the flowability of the coarse crushed pieces M21 containing foreign matter may be reduced due to clogging in the tank 4 or the case 61 of the feeder 6. In addition, the performance of the conveying motor 60 in the feeder 6 may be reduced, resulting in a reduced amount of conveyed coarse crushed pieces M21. As a result, the amount of conveyed pieces M22 cut out will be reduced, and in the process downstream of the coarse fragment supplying device 3, the second web M8 and the sheet S will become thin and may be torn, resulting in a deterioration in quality.

[0083] The CPU can determine an error if En is a negative value that is smaller than the lower limit of a predetermined range, or if Wn is a large value that is larger than the upper limit of a predetermined range. The CPU can also determine an error if Wn reaches the TV in a short time.

[0084] In this case, for example, there is a risk that a large amount of coarsely crushed pieces M21 may flow from the tank 4 into the feeder 6. In addition, there is a risk that a large amount of coarsely crushed pieces M21 may spill out from the outlet 63 even after the rotation of the case 61 of the feeder 6 has stopped. In this case, the fluidity of the coarse crushed pieces M21 may be increased due to the coarse crushed pieces M21 containing foreign matter, etc. Also, the conveying motor 60 of the feeder 6 may be running out of control, causing the conveying amount of the coarse crushed pieces M21 to be large, and there is also a possibility that heavy foreign matter has been mixed in with the coarse crushed pieces M21. In this case, the amount of conveyed pieces M22 cut out will increase, and there is a risk of quality deterioration, such as the second web M8 or sheet S becoming clogged or becoming thicker and uneven in the processes downstream of the coarse fragment supply device 3.

[0085] As described above, if the extrusion amount of the conveyed piece M22 becomes an abnormal value, TH(n+1), which is the next threshold value after the extrusion amount is corrected, may also become an abnormal value. In preparation for this, upper and lower limit values ​​may be determined for TH(n+1), which is the next threshold value after the extrusion amount is corrected. The CPU may determine that an error has occurred if TH(n+1), which is the next threshold value after the extrusion amount is corrected, exceeds the upper or lower limit value. The CPU may also determine upper and lower limit values ​​for R, which is the next rotation speed after the correction of the blades 54 of the agitating blade 5.

[0086] When the CPU determines that no error has occurred during correction (S108: NO), it opens the opening / closing plate 72 using the opening / closing motor and drops the conveying pieces M22 into the pipe 241. Then, when a time has passed for all the conveying pieces M22 to fall, the CPU closes the opening / closing plate 72 using the opening / closing motor. Thereafter, the CPU starts the rotation of the conveyance motor 60 of the feeder 6 again, and starts the rotation of the case 61 of the feeder 6 (S102). The CPU can use TH(n+1), which is the next threshold value after the correction of the cut-out amount, to determine the threshold value. Also, the CPU can rotate the blades 54 of the impeller 5 using R, which is the next rotation speed after the correction. That is, through two feedback controls, the CPU can rotate the blades 54 using the corrected rotation speed R, and can start the feeder 6 cutting out the next conveyed piece M22 using the corrected threshold value TH(n+1).

[0087] In this way, when the CPU does not determine that an error has occurred, it continues to execute the first feedback control and the second feedback control. For example, in the first feedback control, if the nth cutting amount Wn does not reach the target cutting amount TV, the CPU controls the next corrected threshold value TH(n+1) to be larger because the cutting amount of the conveying piece M22 is small. If the next threshold TH(n+1) is increased, the time required for cutting will be longer, and the cutting operation will not end even after the period T has elapsed, which could result in a shortage of the amount of conveyed pieces M22 supplied downstream. For this reason, in the second feedback control, the CPU increases the next corrected rotation speed R of the blades 54 of the mixing impeller 5, thereby controlling the amount of coarsely crushed pieces M21 supplied from the tank 4 to the feeder 6 to be increased. As a result, the CPU can increase the amount of conveyed pieces M22 cut out by the feeder 6, and can approach TV, the target value for the amount of cutting out.

[0088] On the other hand, in the first feedback control, if the nth cutting amount Wn reaches the target cutting amount TV early, the CPU controls the next corrected threshold value TH(n+1) to be smaller because the cutting amount of the conveying piece M22 is large. Since reducing the next threshold value TH(n+1) shortens the time required for cutting, the CPU slows down the next corrected rotation speed R of the blades 54 of the agitator impeller 5 in the second feedback control, thereby controlling the amount of coarsely crushed pieces M21 supplied from the tank 4 to the feeder 6 to be reduced. As a result, the CPU can reduce the amount of conveyed pieces M22 cut out by the feeder 6, and can bring it closer to TV, the target value for the amount of cutting out.

[0089] Even if the CPU monitors the target cutting amount using the measuring device 7 and tries to stop the conveying motor 60 the moment the target cutting amount is reached, the conveyed piece M22 from the case 61 will not stop immediately. Therefore, by performing such feedback control, the cutting amount of the conveyed piece M22 from the feeder 6 can be made closer to the target value.

[0090] On the other hand, if the CPU determines that an error has occurred during correction (S108: YES), it stops the rotation of the stirring motor 50 of the stirring blade 5, thereby stopping the rotation of the blades 54 (S109). Incidentally, the conveying motor 60 has already stopped, and the rotation of the case 61 of the feeder 6 has also stopped.

[0091] In the error determination described above, the CPU may determine that an error has occurred when En, the nth deviation, exceeds the predetermined range three times in a row, rather than determining that an error has occurred when En exceeds the predetermined range only once. As described above, En is the difference between Wn, the nth cropping amount, and TV, the target cropping amount.

[0092] In this case, the CPU may provisionally use the upper or lower limit value of TH(n+1), which is the next threshold value after correction of the cutting amount, as a substitute value. The CPU may also use the upper or lower limit value of R, which is the next rotation speed after correction of the blades 54 of the agitating impeller 5, as a substitute value. If En exceeds the specified range, the CPU can use a more appropriate correction value. Similarly, the CPU can use a more appropriate value for the blades 54 of the agitating impeller 5.

[0093] Similarly, in the above-mentioned error judgment, the CPU may not judge it as an error if the number of times that the cut-out amount Wn does not reach the target value TV even after the period T has elapsed, or the number of times that Wn reaches TV a predetermined time earlier than the period T, is only once.

[0094] As described above, the CPU performs the first feedback control and the second feedback control. However, if the cut-out amount of the conveyed piece M22 does not converge to the target value TV despite these controls, but becomes larger or smaller and diverges, the CPU determines that an error has occurred. If the CPU determines that an error has occurred, it resets the coarse fragment supplying device 3 to stop its entire operation (S110), displays the error through the input / output unit, and then terminates the process.

[0095] The following describes in detail how the CPU handles errors according to the type of error. When the above-mentioned errors occur, the CPU treats them as recoverable errors and displays a message to that effect via the input / output unit. The CPU sets a flag in the storage unit 282 indicating a recoverable error.

[0096] The operator of the sheet production apparatus 100 will know from the display on the input / output unit that a recoverable error has occurred. The operator attempts to remove foreign matter from the coarse fragment supplying device 3. After that, the operator operates the input / output unit to instruct the coarse fragment supplying device 3 shown in Figure 4 to start operating again. When the coarse fragment supplying device 3 starts operating again, the recoverable error may be resolved, and the device may be able to be restored.

[0097] In response to an instruction from the input / output unit, the CPU resumes operation of the coarse fragment supplying device 3 shown in Figure 4. As described above, the CPU executes a series of controls from the start of rotation of the stirring motor 50 and the blades 54 of the stirring blade 5 (S101) to the correction of the rotation speed of the blades 54 of the stirring blade 5 (S107). At this time, the CPU can use the most recent value before the error, rather than the value at the time of the error.

[0098] Next, in determining the error (S108), if the cutting amount Wn normally reaches the target value TV within the period T, the CPU determines that the recoverable error has been resolved (S108: NO) and that the system has recovered from the recoverable error. The CPU then starts the rotation of the case 61 of the feeder 6 (S102) and can continue control. The CPU stops the display of the recoverable error via the input / output unit. The CPU resets the recoverable error flag in the memory unit 282.

[0099] Next, a case will be described in which the CPU determines that an error has occurred again (S108: YES) when determining whether a recoverable error flag has been set (S108). As mentioned above, the CPU can determine that an error has occurred in any of the following cases: for example, when the nth deviation, En, exceeds a predetermined range; when the cut-out amount, Wn, does not reach the target value, TV, even after the period T has elapsed; when Wn reaches TV a predetermined time earlier than the period T; or when the next threshold value, TH(n+1), after correction of the cut-out amount exceeds the upper limit or lower limit.

[0100] When the CPU determines that an error has occurred in the error determination (S108) (S108: YES), it checks the recoverable error flag in the memory unit 282. If the recoverable error flag is set, the CPU can determine that an error has occurred again. There is a risk that the situation is such that it is difficult to return to a normal state under CPU control. The CPU determines that the error is not resolved and that it is an unrecoverable error from which recovery from the error cannot be performed, and displays a message to call a service technician. An unrecoverable error is also called a service technician error. The CPU stops the rotation of the blades 54 (S109).

[0101] Then, the CPU resets the entire crushed piece supplying device 3 to stop its operation (S110), and ends the process. At this time, the CPU stops each part of the sheet production apparatus 100. As a reset process, the CPU sets the cutout amount threshold to the initial value TH0, and also sets the rotation speeds of the stirring motor 50 and the blades 54 to their initial values. That is, in response to the occurrence of a serviceman error, the CPU resets the cutout amount threshold and the rotation speeds of the stirring motor 50 and the blades 54, which are information related to correction. At this time, the CPU may reset each unit of the sheet producing apparatus 100 to its initial value. The CPU sets a flag in the storage unit 282 indicating an unrecoverable error.

[0102] The operator is informed by the input / output unit that an irrecoverable error has occurred and that the operator cannot resolve the error, and requests a service technician to resolve the error. Note that the control board 28 may be provided with a communication unit (not shown), and the CPU may notify an external information processing device (not shown) that provides the service of the occurrence of the irrecoverable error via the communication unit. The service technician can inspect the sheet production apparatus 100 and perform work to resolve the unrecoverable error, such as removing foreign objects or blockages in the coarse fragment supplying device 3. Depending on the situation, the service technician may also repair components of the sheet production apparatus 100 other than the coarse fragment supplying device 3. The service technician will then resolve the unrecoverable error in the coarse fragment supplying device 3 or the sheet production apparatus 100. When the CPU recovers from the unrecoverable error, it can start operating the coarse fragment supplying device 3 or the sheet production apparatus 100 using the initial values ​​associated with the reset.

[0103] 4. Another example of the configuration of the coarse fragment supply device The configuration of another example of a coarse fragment supplying device 3A, which is different from the above-described coarse fragment supplying device 3, will be described with reference to Fig. 5. In the coarse fragment supplying device 3A, the same components as those in the above-described coarse fragment supplying device 3 are given the same reference numerals and descriptions thereof will be omitted.

[0104] The coarse fragment supplying device 3A has two cylinders: a first feeder 6A which is the first cylinder, and a second feeder 6B which is the second cylinder. Specifically, the coarse fragment supplying device 3A has a second feeder 6B and a second measuring instrument 7B in addition to the first feeder 6A and a first measuring instrument 7A. The first feeder 6A and the second feeder 6B each have the same configuration as the feeder 6 of the above-mentioned coarse fragment supplying device 3, and the first measuring instrument 7A and the second measuring instrument 7B each have the same configuration as the measuring instrument 7 of the above-mentioned coarse fragment supplying device 3, so they will only be briefly described.

[0105] The first feeder 6A has a first case 61A with a first screw 64A, and a first conveying motor 60A that rotates the first case 61A. The coarsely crushed pieces M21 stirred by the blades 54 of the stirring blade 5 in the tank 4 are taken in through a first inlet 62A of the first feeder 6A and conveyed, and then thrown into a first bucket 71A of the first measuring instrument 7A through a first outlet 63A. The first measuring instrument 7A has a first load cell 70A, a first bucket 71A, and a first opening / closing plate 72A. A first conveying piece M22A, which is a predetermined amount of coarsely crushed fragments M21 conveyed by the first feeder 6A, enters the first bucket 71A of the first measuring instrument 7A and is weighed by the first load cell 70A. After weighing, the first opening / closing plate 72A of the first bucket 71A opens, and the first conveying piece M22A drops into the pipe 241 and is supplied to the defibration device 13.

[0106] Similarly, the second feeder 6B has a second case 61B having a second screw 64B, and a second conveying motor 60B that rotates the second case 61B. The coarsely crushed pieces M21 stirred by the blades 54 of the stirring blade 5 in the tank 4 are taken in through a second inlet 62B of the second feeder 6B and conveyed, and then thrown into a second bucket 71B of the second measuring instrument 7B through a second outlet 63B. The second measuring instrument 7B has a second load cell 70B, a second bucket 71B, and a second opening / closing plate 72B. The second conveying piece M22B, which is a predetermined amount of coarsely crushed fragments M21 conveyed by the second feeder 6B, enters the second bucket 71B of the second measuring instrument 7B and is weighed by the second load cell 70B. After weighing, the second opening / closing plate 72B of the second bucket 71B opens, and the second conveying piece M22B drops into the pipe 241 and is supplied to the defibration device 13.

[0107] In this first feeder 6A, the coarse crushed pieces M21 are taken in through the first inlet 62A of the first feeder 6A and transported, and the period during which they are deposited from the first outlet 63A into the first bucket 71A of the first measuring instrument 7A overlaps with the period during which they are weighed by the second load cell 70B. After weighing, the second opening / closing plate 72B of the second bucket 71B opens, the second transporting piece M22B falls into the pipe 241, and the period until the second opening / closing plate 72B is closed. In this second feeder 6B, the coarse crushed pieces M21 are taken in through the second inlet 62B of the second feeder 6B and transported, and the period during which they are deposited from the second outlet 63B into the second bucket 71B of the second measuring instrument 7B overlaps with the period during which they are weighed by the first load cell 70A. After weighing, the first opening / closing plate 72A of the first bucket 71A opens, the first transporting piece M22A falls into the pipe 241, and the period until the first opening / closing plate 72A is closed.

[0108] The coarse fragment supplying device 3A is provided with two feeders, a first feeder 6A and a second feeder 6B, which operate alternately, and thus has the following effects. In addition, the target cut-out amount of the conveying pieces M22 supplied to the defibration device 13 by the feeder 6 by the above-mentioned example of the coarse fragment supplying device 3 is the same as the total target cut-out amount of the first conveying pieces M22A and the second conveying pieces M22B supplied to the defibration device 13 by the first feeder 6A and the second feeder 6B by this other example of the coarse fragment supplying device 3A.

[0109] Another example of a coarse fragment supplying device 3A shown in Figure 5 has two feeders, so that the cycle time for cutting out the first conveying piece M22A at the first feeder 6A and the cycle time for cutting out the second conveying piece M22B at the second feeder 6B can be made longer than the cycle time of the coarse fragment supplying device 3.

[0110] The coarse fragment supply device 3A can take a total of 8.0 seconds, for example, with 5.9 seconds for the first feeder 6A to rotate, 0.3 seconds for the first measuring instrument 7A to measure the first conveying piece M22A, and 1.8 seconds for the first feeder 6A to settle down and prepare for the next cutout. The second feeder 6B can also be shifted by 4 seconds from the first feeder 6A, with the same operation and time allocation.

[0111] Compared to the feeder 6 of the example coarse fragment supplying device 3 described above, the first feeder 6A and second feeder 6B of this other example coarse fragment supplying device 3A can gradually cut out the first conveying pieces M22A and the second conveying pieces M22B over twice the time, thereby improving the accuracy of the amount of each cut out. As a result, the coarse fragment supplying device 3A can suppress variations in thickness and density of the second web M8, sheet S, etc. in downstream processes, thereby improving quality.

[0112] The CPU can control the coarse fragment supplying device 3A in the same manner as the control of the coarse fragment supplying device 3 described above. In this case, the CPU can execute the first feedback control for each of the first conveyance motor 60A and the second conveyance motor 60B in the same manner as described above. Also, the CPU can execute the second feedback control for the agitator motor 50 in the same manner as described above. The moving average value THA in the second feedback control described above may be calculated for both the first feeder 6A and the second feeder 6B.

[0113] Furthermore, when the amount of material dispensed from one of the first feeder 6A and the second feeder 6B is large, the CPU can perform a third feedback control such as delaying the timing of dispensing from the other feeder. For example, if the feed rate of the first feeder 6A is 10% higher than the target value, the CPU can perform third feedback control by delaying the timing at which the second feeder 6B starts rotating by 10%. As a result, the total amount of the first conveying pieces M22A and the second conveying pieces M22B per unit time supplied by the coarse fragment supplying device 3A to the defibrating device 13 by the first feeder 6A and the second feeder 6B can be made more constant. The coarse fragment supplying device 3A can further suppress variations in thickness and density of the second web M8, sheet S, etc. in downstream processes, thereby improving quality.

[0114] Furthermore, the CPU can also perform the following control by combining the first feedback control, the second feedback control, and the third feedback control. For example, suppose the amount of material discharged by the first feeder 6A becomes less than the target value. The CPU increases the next stop threshold through the first feedback control. This lengthens the next discharge time. The CPU also advances the timing at which the second feeder 6B starts rotating through the third feedback control. This means that the time taken to supply the coarsely crushed pieces M21 to the first feeder 6A becomes longer, and the timing at which the coarsely crushed pieces M21 are supplied to the second feeder 6B becomes earlier. For these reasons, it is necessary to increase the amount of coarsely crushed fragments M21 supplied to the first feeder 6A and the second feeder 6B. In the second feedback control, the CPU increases the next rotation speed R of the blades 54 of the agitator impeller 5, thereby increasing the amount of coarsely crushed fragments M21 supplied from the tank 4 to the first feeder 6A and the second feeder 6B.

[0115] On the other hand, if the feed rate of the first feeder 6A becomes greater than the target value, the CPU reduces the next stop threshold through the first feedback control. Also, the CPU delays the timing at which the second feeder 6B starts rotating through the third feedback control. Then, in the second feedback control, the CPU slows down the next rotation speed R of the blades 54 of the agitating blade 5. The CPU can reduce the amount of coarse fragments M21 supplied from the tank 4 to the first feeder 6A and the second feeder 6B. By performing such control, the CPU can make the total amount of the first conveying segments M22A and the second conveying segments M22B supplied to the defibrating device 13 per unit time more constant, thereby improving the quality of the sheets S and the like.

[0116] As described above, the feeders of the crushed fragment supplying device 3A are the first feeder 6A, which is the first cylinder, and the second feeder 6B, which is the second cylinder. Note that the CPU can also perform control using other variables as the first feedback control and the second feedback control, as described below. In accordance with the above-mentioned control, the CPU can, as a first feedback control, correct the next operation of the first feeder 6A based on the amount of the first conveying piece M22A measured by the first measuring instrument 7A, and correct the next operation of the second feeder 6B based on the amount of the second conveying piece M22B measured by the second measuring instrument 7B.

[0117] In this case, the CPU can replace the moving average value of each corrected threshold value with the moving average value of the amount of the first conveying segment M22A and the moving average value of the amount of the second conveying segment M22B, respectively, for each feeder. In accordance with the above-mentioned control, the CPU can correct the operation of the agitator motor 50 of the agitator blade 5, which is a motor, as a second feedback control based on the moving average value of both the amount of the first conveying pieces M22A from the first feeder 6A and the amount of the second conveying pieces M22B from the second feeder 6B. Even with this type of control, the CPU can keep the total amount of the first conveying segments M22A and the second conveying segments M22B supplied to the defibrating device 13 per unit time more constant, thereby improving the quality of the sheets S and the like.

[0118] As described above, the sheet production apparatus 100 includes a tank 4 that accumulates coarsely crushed pieces M21, which are pieces of paper, an agitation motor 50 that is a motor for the agitation blades 5, blades 54 that are provided inside the tank 4 and rotate by the force of the agitation motor 50, and a feeder 6 that is a tube that takes in the coarsely crushed pieces M21 that are transported outward by the rotation of the blades 54. Furthermore, the sheet production apparatus 100 includes a pipe 241 that is a transport path for transporting transport pieces M22, which are the coarsely crushed pieces M21 opened from the feeder 6, a production mechanism that defibrates the transported transport pieces M22 to produce a sheet S, and a measuring instrument 7 that measures the amount of coarsely crushed pieces M21 opened from the feeder 6. The CPU of the control unit 281, which is a processor, corrects the next operation of the feeder 6 based on the amount of coarsely crushed fragments M21 so as to reduce the difference between the amount of coarsely crushed fragments M21 measured by the measuring instrument 7 and the target value, and corrects the operation of the stirring motor 50 based on the moving average value of the amount of coarsely crushed fragments M21.

[0119] As a result, the sheet production apparatus 100 equipped with such a CPU can correct the next operation of the feeder 6 based on Wn, which is the amount of paper pieces measured by the measuring device 7 and is the amount of conveyed pieces M22, so as to reduce the difference between Wn and the target value TV, and can also correct the operation of the agitator motor 50 of the agitator blade 5, which is a motor, based on the moving average value of Wn. By using such feedback control, the CPU can bring the cut-out amount of conveying pieces M22 of the feeder 6, which is fed into the defibrating device 13 via the pipe 241, closer to the target value.

[0120] The above describes the embodiments in detail with reference to the drawings, but the specific configuration is not limited to the embodiments, and may be changed, replaced, deleted, etc. as long as it does not deviate from the gist of the present invention. The manner in which feedback control is performed may be changed from that described above. For example, feedback control may be performed on the rotation speed of the case 61. By changing the timing at which the rotation of the case 61 starts through feedback control, the timing at which the rotation of the case 61 stops and the timing at which the opening and closing plate 72 opens and closes may be set to be approximately constant. Furthermore, the calculation method is not limited to that described above. [Explanation of symbols]

[0121] 3,3A...coarse fragment supply device, 4...tank, 5...agitating blade, 6...screw feeder, 6A...first screw feeder, 6B...second screw feeder, 7...measuring instrument, 7A...first measuring instrument, 7B...second measuring instrument, 13...defibration device, 50...agitating motor, 54...blade, 60...conveying motor, 61...case, 70...load cell, 71...bucket, 240,241...pipe, 281...control unit, M21...coarse fragments, M22...conveying fragments.

Claims

1. a tank for accumulating paper scraps; A motor and a blade provided in the tank and rotated by the power of the motor; a tube for catching the paper pieces transported outward by the rotation of the blade; a conveying path for conveying the paper ticket from the tube; a production mechanism that produces sheets by defibrating the transported paper pieces; a measuring device for measuring the amount of the paper pieces from the tube; A sheet production apparatus comprising: a processor that corrects the next operation of the cylinder based on the amount of paper scraps so as to reduce the difference between the amount of paper scraps measured by the measuring device and a target value, and corrects the operation of the motor based on a moving average value of the amount of paper scraps.

2. The cylinders include a first cylinder and a second cylinder, The processor: correcting the next operation of the first cylinder based on the amount of paper scraps from the first cylinder; correcting the next operation of the second cylinder based on the amount of paper scraps from the second cylinder; The sheet production apparatus according to claim 1 , wherein the operation of the motor is corrected based on a moving average value of the amount of the paper chips from the first cylinder and the amount of the paper chips from the second cylinder.

3. The sheet producing apparatus according to claim 1 , wherein the processor resets information related to the correction in response to an error during the correction.

4. The sheet producing apparatus according to claim 1 , wherein the processor resets information related to the correction in response to an error made by a serviceman during the correction.

5. 2. The sheet production apparatus according to claim 1, wherein the processor resets information related to the correction in response to an error occurring when the difference between the amount of paper scraps and the target value exceeds a predetermined range a predetermined number of times in succession during correction.

6. The sheet producing apparatus according to claim 1 , wherein the processor uses proportional-integral control or proportional control when making the correction.

7. a tank for accumulating paper scraps; A motor and a blade provided in the tank and rotated by the power of the motor; a tube for catching the paper pieces transported outward by the rotation of the blade; a conveying path for conveying the paper ticket from the tube; a production mechanism that produces sheets by defibrating the transported paper pieces; A sheet production method for a sheet production apparatus including a measuring device that measures the amount of paper pieces from the tube, A sheet production method for a sheet production device, which corrects the next operation of the cylinder based on the amount of paper scraps so as to reduce the difference between the amount of paper scraps measured by the measuring device and a target value, and corrects the operation of the motor based on a moving average value of the amount of paper scraps.

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