Method for controlling sheet manufacturing apparatus

Abstract

The invention provides a control method of a sheet manufacturing apparatus, which can prevent bad conditions caused by the thickness of the top end of a material sheet. In the control method of the sheet manufacturing device (1), the sheet manufacturing device (1) is provided with a defibrating part (30), a stacking part (50) for forming a material sheet (W), a second conveying part (62) provided with a conveying belt (62a) for conveying the material sheet (W), and a pressing part (70) provided with a pressing roller pair (700) composed of a first roller (71) and a second roller (72) and used for pressing the material sheet (W) to form a belt-shaped sheet (P1). The control method of the sheet manufacturing device (1) comprises the following steps: a first step (S1) of conveying a material sheet (W) through a conveying belt (62a); a second step (S2) of peeling off the tip of the web W from the conveyor belt (62a); a third step (S3) of rotating the first roller (71) in the rotation direction (R1) to bend the tip of the web (W); and a fourth step (S4) of rotating the first roller (71) in the rotation direction (R2) and passing the web (W) between the pair of pressure rollers (700) to fold the tip of the web (W).

Description

Technical Field

[0001] The invention relates to a control method for a thin film manufacturing device. Background Art

[0002] Conventionally, there is known a device for manufacturing a sheet using fibers obtained by defibration of waste paper or the like in air. Among such devices, there is a device for forming a sheet from a sheet containing fibers. For example, Patent Document 1 discloses a sheet manufacturing device including a pressure roller and a heating roller in order to form a sheet into a sheet.

[0003] However, in the device described in Patent Document 1, when the thickness of the top of the sheet is thin, a malfunction may occur in the device. Specifically, in the process of depositing materials such as fibers in the air to form a sheet, there is a problem that it is difficult to control the thickness of the top of the sheet. If the thickness of the top of the sheet becomes thinner, the sheet may sometimes stick to the heating roller. In addition, since the thickness of the top of the sheet formed from the sheet also becomes thinner, the mechanical strength of the top of the sheet is insufficient and it is easy to buckle. In other words, in the conveying path of the sheet, the top of the sheet may get stuck on components such as conveying rollers, thereby causing the possibility of paper jams. The following invention is designed to solve such problems.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2014-208923 Summary of the invention

[0005] The cam is a device for controlling a sheet of fabricating a web, wherein the cam is adapted to move the web from one surface of the web to another surface of the web, wherein the cam is adapted to move the web from one surface of the web to another surface of the web. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram showing the structure of a sheet manufacturing apparatus according to an embodiment.

[0007] Figure 2 It is a flowchart showing the control method of the sheet manufacturing apparatus.

[0008] Figure 3 A schematic diagram showing a method of folding a sheet.

[0009] Figure 4 A schematic diagram showing a method of folding a sheet.

[0010] Figure 5 A schematic diagram showing a method of folding a sheet.

[0011] Figure 6 A schematic diagram showing a method of folding a sheet. DETAILED DESCRIPTION

[0012] In the following embodiment, a sheet manufacturing apparatus 1 that regenerates sheets from paper sheets such as waste paper by a dry method is exemplified as a sheet manufacturing apparatus that manufactures sheets from a material containing fibers. The sheet manufacturing apparatus 1 and a control method thereof will be described below with reference to the drawings.

[0013] In addition, the sheet manufacturing apparatus of the present invention is not limited to a dry method, and may be a wet method. In this specification, a dry method refers to a method that is not performed in a liquid but performed in air such as the atmosphere.

[0014] In the following drawings, the XYZ axes are marked as mutually orthogonal coordinate axes, and the direction pointed by each arrow mark is set as the + direction, and the direction opposite to the + direction is set as the - direction. The Z axis is an imaginary axis along the vertical direction, and the +Z direction is set as the upper side and the -Z direction is set as the lower side. The -Z direction is the direction in which gravity acts. In addition, in the sheet manufacturing device 1, the destination of the conveying direction of the raw material, the sheet, and the sheet is sometimes referred to as the downstream, and the side of the tracing conveying direction is referred to as the upstream. For the convenience of illustration, the size of each component is different from the actual situation.

[0015] 1. Thin sheet manufacturing device

[0016] like Figure 1 As shown in FIG. 1 , the sheet manufacturing apparatus 1 according to the present embodiment includes a first unit group 101, a second unit group 102, and a third unit group 103. The first unit group 101, the second unit group 102, and the third unit group 103 are supported by a frame (not shown). Figure 1 In FIG. 1 , the directions in which the waste paper C, the sheet P3, the slit sheet S, and unnecessary end materials etc. move are shown by blank arrow marks.

[0017] The sheet manufacturing apparatus 1 manufactures a sheet P3 from waste paper C as a material containing fibers. In the sheet manufacturing apparatus 1, a first unit group 101, a third unit group 103, and a second unit group 102 are arranged from the -Y direction toward the +Y direction when viewed from the side in the -X direction.

[0018] Waste paper C is transported from the first unit group 101 to the second unit group 102 via the pipe 21 that crosses the third unit group 103. Then, the waste paper C is defibrated in the second unit group 102 to become fibers, and then is made into a mixture containing a binder and the like. The mixture is transported to the third unit group 103 via the pipe 24. The mixture is made into a web W in the third unit group 103, and then is formed into a strip-shaped sheet P1. The strip-shaped sheet P1 is cut in the first unit group 101 to become a sheet P3.

[0019] The first unit group 101 has a buffer tank 13, a quantitative supply unit 15, a confluence unit 17, and a pipe 21. In the first unit group 101, these structures are arranged in the above order from upstream to downstream. In addition, the first unit group 101 also has a first cutting unit 81, a second cutting unit 82, a tray 84, and a shredding unit 86. The first cutting unit 81 and the second cutting unit 82 cut the strip-shaped sheet P1 into a sheet P3 of a predetermined shape. In addition, the first unit group 101 has a water supply unit 67. The water supply unit 67 is a water storage tank. The water supply unit 67 supplies water for humidification to the first humidification unit 65 and the second humidification unit 66 described later through a water supply pipe not shown in the figure.

[0020] Waste paper C is fed into the buffer box 13 from the material inlet 11. The waste paper C is a piece of shredded waste paper containing fibers such as cellulose. Humidified air is supplied from the second humidifying unit 66 included in the third unit group 103 to the inside of the buffer box 13.

[0021] The defibrated waste paper C is temporarily stored in the buffer tank 13 and then conveyed to the fixed quantity supply unit 15 according to the operation of the sheet manufacturing apparatus 1. The sheet manufacturing apparatus 1 may include a shredder on the upstream side of the buffer tank 13 for shredding the waste paper C and the like.

[0022] The fixed quantity supply unit 15 includes a meter 15a and a supply mechanism (not shown). The meter 15a measures the mass of the waste paper C. The supply mechanism supplies the waste paper C measured by the meter 15a to the downstream confluence unit 17. That is, the fixed quantity supply unit 15 measures the waste paper C according to a predetermined mass by the meter 15a, and supplies it to the downstream confluence unit 17 by the supply mechanism.

[0023] Any digital or analog measuring mechanism can be applied to the measuring device 15a. Specifically, physical sensors such as a force sensor, a spring balance, and a balance can be cited as the measuring device 15a. In the present embodiment, a force sensor is used as the measuring device 15a. The predetermined mass of the waste paper C measured by the measuring device 15a is, for example, several grams to several tens of grams.

[0024] As the supply mechanism, a known technique such as a vibration-type paper feeder can be applied. The supply mechanism may be a structure included in the weighing device 15a.

[0025] The measurement and supply of waste paper C in the fixed-rate supply unit 15 is a batch process. That is, the supply of waste paper C from the fixed-rate supply unit 15 to the confluence unit 17 is intermittently performed. The fixed-rate supply unit 15 may include a plurality of weighing devices 15a, or the plurality of weighing devices 15a may be operated at different times to improve the measurement efficiency.

[0026] In the confluence section 17, the shredded pieces of the slit sheet S supplied from the shredder section 86 and the waste paper C supplied from the fixed quantity supply section 15 are combined and mixed. The slit sheet S and the shredder section 86 will be described later. The waste paper C mixed with the shredded pieces flows from the confluence section 17 into the pipe 21.

[0027] The pipe 21 conveys the waste paper C from the first unit group 101 to the second unit group 102 by airflow generated by a blower (not shown).

[0028] The second unit group 102 has a defibration unit 30, a separation unit 40, a pipe 23, a mixing unit 91, and a pipe 24 as a dry defibration machine. In the second unit group 102, these structures are arranged in the above order from upstream to downstream. In addition, the second unit group 102 also has a recovery unit 95, a compressor 97, a power supply unit 99, a pipe 25 connected to the separation unit 40, and an airflow pipe 29.

[0029] The waste paper C conveyed in the pipe 21 flows into the defibration unit 30. The defibration unit 30 defibrates the waste paper C, which is a material containing fibers, by a dry method to generate defibrated material containing fibers. A known defibration mechanism can be applied to the defibration unit 30. In the present embodiment, a defibration mechanism having a rotating blade is used as the defibration unit 30. The defibration mechanism is a mechanism that shreds and defibrates the waste paper C by a rotating blade to generate fibers.

[0030] The waste paper C passes through the defibration unit 30 , and the entangled fibers contained in the waste paper C are disassembled to form a defibrated material containing fibers, which is then conveyed to the separation unit 40 .

[0031] The separation unit 40 classifies the defibrated fibers. Specifically, the separation unit 40 removes components contained in the fibers that are not necessary for the production of the sheet P3. That is, the separation unit 40 classifies relatively long fibers and relatively short fibers. Since relatively short fibers may reduce the strength of the sheet P3, they are screened and removed by the separation unit 40. In addition, the separation unit 40 removes impurities such as color materials and additives contained in the waste paper C.

[0032] A known separation mechanism can be applied to the separation unit 40. In the present embodiment, a disc-type separation mechanism having a separation filter is used as the separation unit 40. The separation mechanism screens and separates relatively short fibers or impurities passing through the separation filter and relatively long fibers that do not pass through the separation filter. The relatively long fibers are used as defibrated fibers in the material of the web W.

[0033] The humidified air is supplied from the second humidifying unit 66 of the third unit group 103 to the interior of the separation unit 40 .

[0034] The defibrated fibers are passed through the separation unit 40 to remove relatively short fibers. The fibers are then transported to the mixing unit 91 via the pipe 23 by an airflow generated by a blower (not shown) disposed at the top of the airflow pipe 29. Unnecessary parts such as relatively short fibers and impurities are discharged from the pipe 25 to the recovery unit 95.

[0035] The mixing unit 91 mixes the binder with the fibers in the air to form a mixture. Although not shown in the figure, the mixing unit 91 includes a flow path through which the fibers are conveyed, a fan, a hopper, a supply pipe, and a valve.

[0036] The hopper is connected to the flow channel of the fiber via a supply pipe. A valve is provided on the supply pipe between the hopper and the flow channel. The hopper supplies a binder such as starch into the flow channel. The valve adjusts the mass of the binder supplied from the hopper to the flow channel. Thus, the mixing ratio of the fiber and the binder is adjusted.

[0037] The mixing unit 91 has a similar structure for supplying a coloring material, an additive, and the like in addition to the above-mentioned structure for supplying the binder.

[0038] The fan of the mixing unit 91 uses the generated airflow to transport the fibers downstream and mix the binder and the like into the air to form a mixture. The mixture flows from the mixing unit 91 into the pipe 24 .

[0039] The recovery unit 95 includes a filter (not shown). The filter filters out unnecessary parts such as relatively short fibers conveyed from the pipe 25 by the airflow.

[0040] The compressor 97 generates compressed air. The filter may be clogged by fine particles in an unnecessary portion. The compressed air generated by the compressor 97 is blown toward the filter to blow off the attached particles and clean the filter.

[0041] The power supply unit 99 includes a power supply device (not shown) for supplying power to the sheet manufacturing apparatus 1, and the control unit 5. The power supply unit 99 distributes the power supplied from the outside to each component of the sheet manufacturing apparatus 1.

[0042] Although not shown in the figure, the control unit 5 includes a CPU (Central Processing Unit) and a storage unit including a RAM (Random Access Memory) and a ROM (Read Only Memory). Various programs for controlling the sheet manufacturing device 1 are stored in the storage unit. The control unit 5 may also include dedicated hardware (Application Specific Integrated Circuit: ASIC (Application Specific Integrated Circuit)) for executing at least a part of the various processes. That is, the control unit 5 may also be configured as one or more processors that operate according to a computer program (software), one or more dedicated hardware circuits such as ASIC, or a circuit including a combination thereof.

[0043] The processor includes a CPU and a memory such as a RAM and a ROM. The memory stores program codes or instructions configured to cause the CPU to execute a process. The memory, i.e., the computer-readable medium, includes all media that can be accessed by a general-purpose or special-purpose computer.

[0044] The control unit 5 is electrically connected to each component of the sheet manufacturing apparatus 1 including the second conveying unit 62, the air jet unit 200, and the pressurizing unit 70, and comprehensively controls the operation of these components. In particular, the control unit 5 is also responsible for control related to folding of the web W described later.

[0045] The third unit group 103 deposits and compresses the mixture containing fibers to form a strip-shaped sheet P1 as recycled paper. The third unit group 103 includes a depositing unit 50, a first conveying unit 61, a second conveying unit 62, a first humidifying unit 65, an air jetting unit 200, a second humidifying unit 66, a draining unit 68, and a pressurizing unit 70. The second conveying unit 62 is an example of a web conveying unit of the present invention.

[0046] In the third unit group 103, the stacking section 50, the first conveying section 61, the second conveying section 62, the first humidifying section 65, and the pressurizing section 70 are arranged in the above order from upstream to downstream. The air injection section 200 is located inside the second conveying section 62 and is arranged at the downstream end of the conveying path of the web W in the second conveying section 62. The second humidifying section 66 is arranged below the first humidifying section 65.

[0047] The accumulation unit 50 accumulates the mixture generated from the defibrated material by airflow and gravity to form a web W. The accumulation unit 50 includes a drum member 53, a blade member 55 provided in the drum member 53, a housing 51 for housing the drum member 53, and a suction unit 59. The mixture is sucked into the drum member 53 from the pipe 24.

[0048] The first conveyor 61 is disposed below the accumulation unit 50. The first conveyor 61 includes a mesh belt 61a and five extension rollers (not shown) for extending the mesh belt 61a. The suction unit 59 faces the roller member 53 via the mesh belt 61a in the direction along the Z axis.

[0049] The blade member 55 is located inside the drum member 53 and is driven to rotate by a motor (not shown). The drum member 53 is a semi-cylindrical screen. A net having the function of a screen is provided on the side of the drum member 53 facing downward. The drum member 53 allows particles such as fibers or mixtures that are smaller than the size of the mesh opening of the screen to pass from the inside to the outside.

[0050] The mixture is stirred by the rotating blade member 55 in the drum member 53 and discharged to the outside of the drum member 53. The humidified air is supplied from the second humidifying unit 66 to the inside of the drum member 53.

[0051] The suction unit 59 is arranged below the roller member 53. The suction unit 59 sucks the air in the housing 51 through the multiple holes of the mesh belt 61a. As a result, an airflow is generated to deposit the mixture on the mesh belt 61a. The multiple holes of the mesh belt 61a allow air to pass through, and make it difficult for fibers or adhesive materials contained in the mixture to pass through. As a result, the mixture released to the outside of the roller member 53 is sucked downward together with the air. The suction unit 59 is a known suction device such as a suction fan.

[0052] The mixture is dispersed in the air in the housing 51 , and is deposited on the upper surface of the mesh belt 61 a by gravity and the airflow generated by the suction unit 59 , thereby forming a web W.

[0053] The mesh belt 61a is an endless belt and is stretched by five stretching rollers. The mesh belt 61a is stretched by the self-rotation of the stretching rollers. Figure 1The first conveying unit 61 rotates counterclockwise in the mesh belt 61. As a result, the mixture is continuously deposited on the mesh belt 61a to form a sheet W. The sheet W contains a lot of air and expands softly. The first conveying unit 61 conveys the formed sheet W downstream by rotating the mesh belt 61a.

[0054] The second conveying unit 62 conveys the web W instead of the first conveying unit 61 at the downstream of the first conveying unit 61. The second conveying unit 62 peels the web W from the upper surface of the mesh belt 61a and conveys it toward the pressurizing unit 70. The second conveying unit 62 is located above the conveying path of the web W and is arranged slightly upstream of the starting point of the return side of the mesh belt 61a. The +Y direction of the second conveying unit 62 and the -Y direction of the mesh belt 61a partially overlap in the vertical direction.

[0055] The second conveying unit 62 includes a conveying belt 62a, four suspension rollers (not shown), and a suction unit 62b. The conveying belt 62a is provided with a plurality of holes for air to pass through. The conveying belt 62a is suspended by the four suspension rollers and rotates to move the conveying belt 62a. Figure 1 Rotate clockwise.

[0056] The suction section 62b is located on the conveying path of the web W in the second conveying section 62, and is arranged above the conveyor belt 62a. The suction section 62b sucks the lower air upward through the multiple holes of the conveyor belt 62a. As a result, one surface, which is the upper surface of the web W, is adsorbed on the lower surface of the conveyor belt 62a. By rotating the conveyor belt 62a in this state, the web W is adsorbed on the conveyor belt 62a and conveyed downstream. In other words, the conveyor belt 62a conveys the web W in a manner of contacting one surface of the web W. The suction section 62b is a well-known suction device such as a suction fan.

[0057] The first humidifying section 65 humidifies the web W containing fibers accumulated by the accumulation section 50 of the third unit group 103. Specifically, the first humidifying section 65 is, for example, a mist humidifier, and supplies mist M from below to the web W conveyed by the second conveying section 62 to humidify the web W. The first humidifying section 65 is arranged below the second conveying section 62 and is opposite to the web W conveyed by the second conveying section 62 in the direction along the Z axis. For the first humidifying section 65, a known humidifying device such as an ultrasonic type can be applied.

[0058] By humidifying the web W with the mist M, the function of the adhesive material contained in the web W is promoted, thereby improving the strength of the sheet P3. In addition, since the web W is humidified from below, water droplets generated by the mist can be prevented from falling onto the web W. Moreover, since the web W is humidified from the opposite side of one surface of the web W in contact with the conveyor belt 62a, the web W can be reduced from adhering to the conveyor belt 62a. The second conveyor unit 62 conveys the web W toward the pressurizing unit 70.

[0059] The air injection unit 200 is located in the second conveying unit 62 and is arranged downstream of the suction unit 62b. Although not shown in the figure, the air injection unit 200 has a compressed air tank and a spray nozzle. The compressed air tank supplies compressed air to the spray nozzle. The air injection unit 200 sprays compressed air downward from the spray nozzle toward the web W. The compressed air is supplied and stored in the compressed air tank, for example, from a compressor (not shown) used by the air injection unit 200.

[0060] The spray nozzle is an elongated opening extending in the direction along the X-axis. The spray nozzle is opposite to the web W conveyed by the conveyor belt 62a in the direction along the Z-axis. The compressed air sprayed from the air spray unit 200 passes through the conveyor belt 62a and hits one surface of the web W adsorbed on the surface below the conveyor belt 62a. At this time, since the length of the spray nozzle in the direction along the X-axis is longer than the length of the web W, the compressed air sprayed by the spray nozzle is blown to the entire width of the web W.

[0061] Thus, the sheet W is peeled off from the conveyor belt 62a. The injection of compressed air by the air injection unit 200 is performed when the top end of the downstream side of the sheet W reaches the area opposite to the air injection unit 200. And, after the top end of the sheet W is peeled off from the conveyor belt 62a, the top end of the sheet W is bent and the top end of the sheet W is folded. Then, the sheet W is delivered from the second conveyor unit 62 to the pressurizing unit 70. The details of the bending and folding of the sheet W will be described later.

[0062] The press section 70 includes a press roller pair 700 composed of a first roller 71 and a second roller 72. The press section 70 allows the web W to pass between the press roller pair 700, and forms a strip-shaped sheet P1 from the web W.

[0063] The first roller 71 and the second roller 72 form a pair and are each a substantially cylindrical member. The rotation axis of the first roller 71 and the rotation axis of the second roller 72 are arranged along the X-axis. The first roller 71 is arranged substantially below the conveying path of the web W, and the second roller 72 is arranged substantially above the conveying path of the web W. The first roller 71 and the second roller 72 rotate while approaching each other while the web W forms a strip-shaped sheet P1.

[0064] In the direction along the X axis, the length of the first roller 71 and the length of the second roller 72 are longer than the length of the web W, that is, the width of the web W. Therefore, the web W is reliably clamped between the first roller 71 and the second roller 72 .

[0065] The diameter of the first roller 71 is larger than the diameter of the second roller 72. For example, the diameter of the first roller 71 is 110 mm or more and 150 mm or less, and the diameter of the second roller 72 is 80 mm or more and 110 mm or less.

[0066] The first roller 71, for example, includes a core iron and a surface layer covering the core iron. As the core iron, a hollow structure composed of aluminum, iron, stainless steel, etc. can be listed. As the material of the surface layer, fluororesins such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), ETFE (tetrafluoroethylene-ethylene copolymer), and silicone resin can be listed. As a result, the demolding property of the first roller 71 relative to the sheet W can be improved. In addition, the wear or damage of the core iron can be suppressed.

[0067] The second roller 72 includes, for example, a core iron, an intermediate layer, and a surface layer. The core iron may be a hollow structure made of aluminum, iron, stainless steel, etc. The intermediate layer covers the core iron and is covered by the surface layer. In other words, there is an intermediate layer between the core iron and the surface layer.

[0068] As the material of the intermediate layer, elastomers such as silicone rubber and polyurethane rubber can be cited. The hardness of the elastomer is preferably 30 or more and 70 or less, and more preferably 40 or more and 60 or less, based on the measured value of the ASKER C hardness meter. The thickness of the intermediate layer is preferably 1 mm or more and 10 mm or less, and more preferably 1 mm or more and 5 mm or less.

[0069] Examples of the material of the surface layer include fluororesins such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and ETFE (tetrafluoroethylene-ethylene copolymer).

[0070] By configuring the second roller 72 to have the above-described structure, the releasability of the second roller 72 with respect to the web W is improved. In addition, the wear and damage of the intermediate layer can be suppressed.

[0071] The web W is pressurized by passing between the first roller 71 and the second roller 72. The pressure applied to the web W by the first roller 71 and the second roller 72 is preferably 0.1 MPa or more and 15.0 MPa or less, more preferably 0.2 MPa or more and 10.0 MPa, and further preferably 0.4 MPa or more and 8.0 MPa or less. Thus, the degradation of the fibers in the web W can be suppressed.

[0072] The first roller 71 has an electrothermal heater built therein, and has a function of raising the temperature of the roller surface. The second roller 72 also preferably has a function of raising the temperature of the roller surface by an electrothermal heater, similarly to the first roller 71 .

[0073] The surface temperature of the first roller 71, that is, the temperature of the surface layer of the first roller 71 in contact with the web W, is preferably 100° C. to 130° C. The surface temperature of the second roller 72, that is, the temperature of the surface layer of the second roller 72 in contact with the web W, is preferably 80° C. to 100° C.

[0074] The first roller 71 has fine irregularities on its surface. The irregularities of the surface are indexed by the surface roughness measured by a surface roughness meter. The surface roughness of the surface of the first roller 71 is preferably 2 μm or more and 8 μm or less, and more preferably 3 μm or more and 6 μm or less in terms of arithmetic mean roughness (Ra). In addition, it is preferably 15 μm or more and 70 μm or less, and more preferably 25 μm or more and 50 μm or less in terms of maximum height (Rz). The irregularities on the surface of the first roller 71 may come from the surface of the core iron or from the surface of the surface layer. These irregularities are formed, for example, by sandblasting or spraying.

[0075] Since the second roller 72 has an elastic intermediate layer as described above, if the material sheet W is sandwiched between the first roller 71 and the second roller 72 and formed, it is easy to produce unevenness on the surface of the strip-shaped thin sheet P1 that contacts the second roller 72. On the other hand, if the surface of the first roller 71 is made smooth, the surface of the strip-shaped thin sheet P1 that contacts the first roller 71 is easy to become smooth. In this case, it is easy to produce a difference in unevenness, that is, a surface quality difference, on the front and back surfaces of the strip-shaped thin sheet P1. Such a surface quality difference will become a difference in smoothness between the front and back surfaces of the thin sheet P3, so when the thin sheet P3 is used as copy paper, etc., it is sometimes necessary to distinguish between the front and back surfaces.

[0076] In contrast, the surface quality difference between the front and back of the strip-shaped sheet P1 is reduced by the fine concavoconvexity of the surface of the first roller 71 described above, so that the front and back of the sheet P3 can be used without distinguishing them. In addition, in the bending of the sheet W described later, the followability of the sheet W relative to the first roller 71 can be improved, so that the bending can be made easier.

[0077] The first roller 71 is driven to rotate by a stepping motor (not shown). The second roller 72 is a driven roller that is not driven by a motor but rotates in conjunction with the first roller 71. Therefore, the second roller 72 rotates in the opposite direction to the first roller 71 when viewed from the side in the -X direction.

[0078] The web W is fed downstream while being heated and pressurized while being sandwiched between the first roller 71 and the second roller 72. That is, the web W continuously passes through the pressurizing section 70, and is press-formed while being heated. By using the first roller 71 and the second roller 72 as a pair of forming members, the web W can be efficiently heated and pressurized.

[0079] The web W passes through the pressurizing unit 70, thereby reducing the air contained therein from a soft state containing a lot of air and increasing the density. Then, the fibers are bonded to each other by a bonding material, thereby forming a strip-shaped sheet P1. The strip-shaped sheet P1 is conveyed to the first unit group 101 by a conveying roller (not shown).

[0080] Here, since the web W is formed by the accumulation of the mixture, the thickness of the web W is unstable in the initial stage of forming the web W, that is, in the area of ​​the top end of the web W. In general, the thickness of the top end of the web W tends to be thinner than the thickness of the rear portion. If the above-mentioned thickness becomes thinner, it is possible to cause undesirable conditions such as adhesion to the first roller 71 or the second roller 72 and clogging of the strip-shaped sheet P1 in the path. In contrast, in the sheet manufacturing device 1, the control method described later is used so that the top end is overlapped in a double layer to increase the thickness, thereby preventing the occurrence of the above-mentioned undesirable conditions. In the following description, there is also a case where the top end on the downstream side of the conveying direction of the web W is simply referred to as the top end of the web W.

[0081] The second humidifying section 66 is disposed below the first humidifying section 65. As the second humidifying section 66, a well-known vaporization type humidifying device can be applied.

[0082] The second humidifying unit 66 humidifies a predetermined area of ​​the sheet manufacturing apparatus 1. The predetermined area refers to one or more areas in the buffer box 13, the separation unit 40, and the drum member 53 of the stacking unit 50. Specifically, the humidified air is supplied to the above-mentioned area from the second humidifying unit 66 via a plurality of tubes (not shown). The humidified air suppresses the charging of waste paper C, fibers, etc. in the above-mentioned various structures, thereby suppressing the adhesion to the components caused by these static electricity.

[0083] The drain unit 68 is a drain tank. The drain unit 68 is used in the first humidifying unit 65 and the second humidifying unit 66, etc., and collects and stores old water. The drain unit 68 can be removed from the sheet manufacturing apparatus 1 as needed to discard the accumulated water.

[0084] The strip-shaped sheet P1 conveyed to the first unit group 101 arrives at the first cutting unit 81. The first cutting unit 81 cuts the strip-shaped sheet P1 in a direction intersecting the conveying direction, for example, in a direction along the X axis. The strip-shaped sheet P1 is cut into single sheets P2 by the first cutting unit 81. The single sheets P2 are conveyed from the first cutting unit 81 to the second cutting unit 82.

[0085] The second cutting unit 82 cuts the single sheet P2 in the conveying direction, for example, in the direction along the Y axis. Specifically, the second cutting unit 82 cuts both ends of the single sheet P2 in the X axis direction. Thus, the single sheet P2 becomes a sheet P3 of a predetermined shape, such as A4 size or A3 size.

[0086] When the single sheet P2 is cut into sheets P3 by the second cutting unit 82, a slit sheet S is produced as an end material. The slit sheet S is conveyed in the substantially -Y direction and reaches the shredder 86 as a shredder. The shredder 86 shreds the slit sheet S into shredded pieces and supplies them to the merging unit 17. Between the shredder 86 and the merging unit 17, a mechanism for measuring the shredded pieces of the slit sheet S and supplying them to the merging unit 17 may be provided.

[0087] The sheet P3 is conveyed substantially upward and accumulated on the tray 84. As described above, the sheet P3 is manufactured by the sheet manufacturing apparatus 1. The sheet P3 can be used as a substitute for copy paper or the like, for example.

[0088] 2. Control method of sheet manufacturing device

[0089] like Figure 2As shown, the control method of the sheet manufacturing device 1 according to the present embodiment includes a first step S1, a second step S2, a third step S3, a fourth step S4 and a fifth step S5. These steps are executed in the above order according to the control of the control unit 5. Figures 3 to 6 To explain each of the above steps. Figures 3 to 6 In the description, unless otherwise specified, the description is given for the state when viewed from the side in the -X direction.

[0090] like Figure 3 As shown, in the first step S1 , the web W is conveyed downstream in the −Y direction by the second conveying unit 62 .

[0091] In the original forming operation of passing the web W between the first roller 71 and the second roller 72, the first roller 71 rotates in the counterclockwise rotation direction R2, and the second roller 72 rotates in the clockwise rotation direction R1. In the first step S1, since the web W has not yet reached between the first roller 71 and the second roller 72, the rotation of the first roller 71 and the second roller 72 can be stopped, and the first roller 71 and the second roller 72 can also be stopped as shown in FIG. Figure 3 Then, rotate in the above directions respectively.

[0092] Then, the process proceeds to the second step S2 at the time point when the tip of the web W passes through the area opposite to the air jet unit 200. In addition, as a method for determining whether the tip of the web W has reached the area opposite to the air jet unit 200, an optical sensor is used to detect the position of the tip of the web W. In addition, as another method, the following method can be applied, that is, the time from the start of driving of the stacking unit 50 to the tip of the web W reaching the position opposite to the air jet unit 200 is measured in advance, and the time is preset to implement timing control.

[0093] like Figure 4 As shown, in the second step S2, the tip of the web W is peeled off from the conveyor belt 62a. Specifically, in the second step S2, the tip of the web W is peeled off from the conveyor belt 62a by the injection of compressed air from the air injection unit 200. Since the web W is continuously conveyed by the conveyor belt 62a during this period, the tip of the web W hangs down and contacts the first roller 71.

[0094] At this time, if Figure 4 Thus, it is preferable to rotate the first roller 71 in the clockwise rotation direction R1 as the first direction before proceeding to the third step S3 in the subsequent stage. In this case, the second roller 72 is driven by the first roller 71 and rotates in the counterclockwise rotation direction R2.

[0095] In the second step S2, in addition to peeling the top end of the web W from the conveyor belt 62a by compressed air, the direction of the top end of the web W is changed to be substantially downward. As a result, in the third step S3 of the subsequent stage, the top end of the web W is easily bent. Then, the process proceeds to the third step S3.

[0096] like Figure 5 As shown, in the third step S3, the first roller 71 is rotated in the rotation direction R1 as the first direction while the tip of the web W is in contact with the side surface of the first roller 71. The tip of the web W is pulled by the rotation of the first roller 71 and is bent in the approximately +Y direction. At this time, the second roller 72 is driven by the first roller 71 and rotates in the rotation direction R2 of the counterclockwise rotation.

[0097] In the third step S3, the rotation of the first roller 71 in the rotation direction R1 is set to a predetermined time. The distance by which the top end of the sheet W is bent in the approximately +Y direction is adjusted by the diameter, rotation speed, and rotation time of the first roller 71. For example, the time for rotating the first roller 71 in the rotation direction R1 is set to 3 seconds after the compressed air is injected by the air injection unit 200. As a result, the top end of the sheet W is bent in the +Y direction by approximately 60 mm. Then, the process proceeds to the fourth step S4.

[0098] like Figure 6 As shown, in the fourth step S4, the first roller 71 is rotated in the rotation direction R2 which is the second direction opposite to the first direction, and the second roller 72 is driven by the first roller 71 and rotated in the rotation direction R1. At the same time, the web W is passed between the first roller 71 and the second roller 72 which are the pressure roller pair 700. As a result, the top end of the web W is pressed and folded. Then, the process proceeds to the fifth step S5.

[0099] In the fifth step S5, following the fourth step S4, the first roller 71 is rotated in the rotation direction R2, and the second roller 72 is rotated in the rotation direction R1. As a result, the web W is pressurized while passing between the pressure roller pair 700, and is heated by the first roller 71 and the second roller 72. As a result, the strip-shaped sheet P1 is continuously formed. The conveying path of the strip-shaped sheet P1 is Figure 6 Subsequently, the strip-shaped sheet P1 is conveyed toward the first cutting section 81 described above.

[0100] The folded distance at the downstream end of the strip-shaped sheet P1 in the conveying direction, i.e., the distance by which the web W is doubled, may be, for example, 20 mm or more in the conveying direction. The distance is adjusted by the distance by which the end of the web W is bent in the third step S3.

[0101] In addition, the top of the sheet W is not limited to being folded by overlapping two layers. The third step S3 and the fourth step S4 described above can also be repeatedly performed to overlap the top of the sheet W by three or more layers. In this way, the thickness and strength at the top of the sheet W are further increased.

[0102] In addition, in the second step S2, the conveying speed of the sheet W after the top end is peeled off and the rotation speed of the first roller 71 can be adjusted so that the top end of the sheet W is rolled into a spiral shape and bent. Accordingly, the thickness of the top end of the sheet W becomes thicker, thereby further increasing the strength of the top end of the sheet W.

[0103] According to this embodiment, the following effects can be obtained.

[0104] Even when the tip of the web W is thin, the occurrence of a bad condition can be prevented. Specifically, since the tip of the web W is folded, the web W is doubled at the tip of the web W. Therefore, even when the tip of the web W before folding is thin, the web W can ensure a thickness and strength that are unlikely to cause a bad condition. Therefore, even when the tip of the web W is thin, a control method for the sheet manufacturing apparatus 1 that prevents the occurrence of a bad condition can be provided.

[0105] Explanation of symbols

[0106] 1…sheet manufacturing device; 30…defibration section; 50…stacking section; 62…second conveying section as a sheet conveying section; 62a…conveyor belt; 70…pressing section; 71…first roller; 72…second roller; 200…air jet section; 700…pressing roller pair; P1…belt-shaped sheet; P3…sheet; R1…rotation direction as a first direction; R2…rotation direction as a second direction; S1…first step; S2…second step; S3…third step; S4…fourth step; S5…fifth step; W…sheet.

Claims

1. A method for controlling a sheet manufacturing device, the sheet manufacturing device manufacturing a sheet from a material containing fibers, wherein: The sheet manufacturing device comprises: a defibration section for defibration of a material containing the fibers to generate a defibrated product; an accumulation section for stacking the defibrated material to form a web; a web conveying portion having a conveying belt in contact with one surface of the web to convey the web; a pressurizing section including a pressurizing roller pair consisting of a first roller and a second roller, and pressurizing the web to form the sheet, The control method of the sheet manufacturing device comprises: The first step is to convey the material sheet through the conveyor belt; The second step is to peel the top end of the sheet off the conveyor belt; The third step is to rotate the first roller in a first direction to bend the top end of the sheet; In a fourth step, the first roller is rotated in a second direction opposite to the first direction, and the web is passed between the pair of pressure rollers to fold the top end of the web.

2. The control method of a sheet manufacturing apparatus according to claim 1, wherein: The sheet manufacturing device includes an air injection unit that injects compressed air. In the second step, the compressed air is sprayed so that the top end of the web is peeled off from the conveyor belt and comes into contact with the first roller.

3. The control method of a sheet manufacturing apparatus according to claim 1, wherein: In the third step, the first roller is rotated in the first direction for a predetermined time to bend the top end of the web.

4. The control method of a sheet manufacturing apparatus according to claim 1, wherein: having a fifth step subsequent to the fourth step, In the fifth step, the web is pressed while passing between the pair of pressurizing rollers, and is heated and formed by the first roller.

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