Apparatus for producing sheet, and method for producing sheet

Abstract

To provide an apparatus for producing a sheet and a method for producing a sheet which do not leave a deposit when stopping.SOLUTION: An apparatus 1 for producing a sheet includes: a defibrating part 30 for defibrating a material to generate a defibrated product; a deposition part 50 for depositing a defibrated product to form a web W; a forming part 70 for pressing the web W to form a belt-like sheet P1; a transportation part 60 having a deposition transportation part 61 and a back face transportation part 62 for transporting the web W disposed between the deposition part 50 and the formation part 70; a recovery part 96 disposed corresponding to the deposition transportation part 61; and a control part 5 for controlling operation of the apparatus 1 for producing the sheet, where the deposition transportation part 61 is disposed more upstream than a back face transportation part 62 in a transportation direction of the web W, and the control part 5 breaks the web W between the deposition transportation part 61 and the back face transportation part 62 into an upstream side web W1 and a down stream side web W2, and recovers the upstream side web W1 to the recovery part 96 and forms the downstream side web W2 to a belt-like sheet P1 by controlling the transportation part 60 when stopping operation of the apparatus 1 for producing a sheet.SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[0002] Conventionally, there have been known devices for producing sheets from fibers derived from waste paper, etc. For example, Patent Document 1 discloses a sheet production device that accumulates fibers in the air and then forms them into a sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-112740 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a problem with how to deal with the deposits that remain as work in progress in the deposit section when the apparatus is stopped, which is not described in Patent Document 1. [Means for solving the problem]

[0005] The sheet manufacturing apparatus is a sheet manufacturing apparatus that manufactures a sheet from a material that contains fibers, and includes: a defibrating unit that defibrates the material to produce defibrated material; a deposition unit that deposits the defibrated material to form a web; a forming unit that compresses the web to form the sheet; a conveying unit that is arranged between the deposition unit and the forming unit and has a deposition conveying unit and a backside conveying unit that conveys the web; a recovery unit that is arranged corresponding to the deposition conveying unit; and a control unit that controls operation of the sheet manufacturing apparatus, wherein the deposition conveying unit is arranged upstream of the backside conveying unit in the conveying direction of the web, and when the control unit stops operation of the sheet manufacturing apparatus, it controls the conveying unit to break the web into an upstream web and a downstream web between the deposition conveying unit and the backside conveying unit, recover the upstream web in the recovery unit, and form the downstream web into the sheet.

[0006] The sheet manufacturing method is a sheet manufacturing method using a sheet manufacturing apparatus comprising: a defibrating unit that defibrates a fiber-containing material to produce defibrated material; a deposition unit that deposits the defibrated material to form a web; a forming unit that compresses the web to form a sheet; a conveying unit that is arranged between the deposition unit and the forming unit and has a deposition conveying unit and a backside conveying unit that conveys the web; a recovery unit that is arranged corresponding to the deposition conveying unit; and a control unit that controls operation of the sheet manufacturing apparatus, wherein the sheet manufacturing method comprises, when the operation of the sheet manufacturing apparatus is stopped, a step of stopping conveyance of the web by the deposition conveying unit and continuing conveyance of the web by the backside conveying unit, and breaking the web into an upstream web and a downstream web between the deposition conveying unit and the backside conveying unit; a step of transporting the downstream web to the forming unit and manufacturing the sheet using the downstream web; and a step of restarting the deposition conveying unit and recovering the upstream web to the recovery unit. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a sheet manufacturing apparatus according to an embodiment. [Figure 2] FIG. 3 is a schematic diagram showing a detailed configuration of a transport unit. [Figure 3] FIG. 4 is a flowchart showing steps of an operation shutdown operation in the sheet manufacturing method. [Figure 4] FIG. 4 is a schematic diagram showing a shutdown operation of the sheet manufacturing apparatus. [Figure 5] FIG. 4 is a schematic diagram showing a shutdown operation of the sheet manufacturing apparatus. [Figure 6] FIG. 4 is a schematic diagram showing a shutdown operation of the sheet manufacturing apparatus. [Figure 7] FIG. 4 is a schematic diagram showing a shutdown operation of the sheet manufacturing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the following embodiments, a sheet manufacturing apparatus 1 for dry-processing a sheet from a material such as waste paper containing fibers, and a sheet manufacturing method using the sheet manufacturing apparatus 1, will be described with reference to the drawings. The sheet manufacturing apparatus of the present invention is not limited to a dry-processing apparatus, and may be a wet-processing apparatus. In this specification, the term "dry-processing" refers to a process carried out in air, such as the atmosphere, rather than in a liquid.

[0009] In the following drawings, X, Y, and Z axes are assigned as mutually orthogonal coordinate axes, with the direction indicated by each arrow being the + direction and the direction opposite the + direction being the - direction. The Z axis is a virtual axis along the vertical direction, with the +Z direction being upward and the -Z direction being downward. The -Z direction is the vertical direction. In addition, in the sheet manufacturing apparatus 1, the end of the conveying direction of the material, web, sheet, etc. is referred to as downstream, and the side going backward in the conveying direction is referred to as upstream. For ease of illustration, the sizes of each component are different from the actual size.

[0010] As shown in Fig. 1, the sheet manufacturing apparatus 1 according to this 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). In Fig. 1, the directions in which the pieces of paper C, the sheet P3, the slit pieces S, and unnecessary scraps move are indicated by hollow arrows. In the following description, a collection of multiple pieces of paper C will also be simply referred to as a piece of paper C.

[0011] The sheet manufacturing apparatus 1 manufactures a sheet P3 from paper pieces C, which are a material containing fibers such as recycled paper. 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 to the +Y direction in a side view from the -X direction.

[0012] The paper pieces C are transported from the first unit group 101 to the second unit group 102 via a pipe 21 that traverses the third unit group 103. The paper pieces C are then subjected to defibration and other processes in the second unit group 102 to become a defibrated material, which is an aggregate of fibers, and a binder and other materials are added. The defibrated material is transported to the third unit group 103 via a pipe 24. The defibrated material is made into a web W in the third unit group 103 and then formed into a belt-shaped sheet P1. The belt-shaped sheet P1 is cut in the first unit group 101 to become a sheet P3.

[0013] The first unit group 101 has a buffer tank 13, a constant volume supply unit 15, a junction unit 17, and a pipe 21. In the first unit group 101, these components are arranged in the above order from upstream to downstream. 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.

[0014] Furthermore, a sheet conveying section 63 is disposed across the third unit group 103 and the first unit group 101. The sheet conveying section 63 conveys a strip-shaped sheet P1, a cut sheet P2, a sheet P3, and a slit piece S. The first cutting section 81 and the second cutting section 82 cut the strip-shaped sheet P1 into a sheet P3 having a predetermined shape.

[0015] Furthermore, first unit group 101 has water supply unit 267. Water supply unit 267 is a water storage tank. Water supply unit 267 supplies water for humidification to each of first humidifier unit 265 and second humidifier unit 266 (described later) via a water supply pipe (not shown).

[0016] The paper pieces C are fed into the buffer tank 13 from the raw material feed port 11. The paper pieces C contain fibers such as cellulose, and are, for example, pieces of shredded waste paper. Humidified air is supplied into the buffer tank 13 from the second humidifier 266 provided in the third unit group 103.

[0017] The paper pieces C to be defibrated are temporarily stored in the buffer tank 13, and then transported to the constant quantity supply unit 15 in accordance with the operation of the sheet manufacturing apparatus 1. The sheet manufacturing apparatus 1 may be provided with a shredder upstream of the buffer tank 13 that shreds the paper pieces C and the like.

[0018] The constant-quantity supply unit 15 has a weighing device 15a and a supply mechanism (not shown). The weighing device 15a measures the mass of the pieces of paper C. The supply mechanism supplies the pieces of paper C weighed by the weighing device 15a to the downstream junction 17. That is, the constant-quantity supply unit 15 measures the pieces of paper C by predetermined mass using the weighing device 15a, and supplies them to the downstream junction 17 using the supply mechanism.

[0019] The weighing device 15a may be either a digital or analog weighing mechanism. Specifically, the weighing device 15a may be a physical sensor such as a load cell, a spring balance, or a balance. In this embodiment, a load cell is used as the weighing device 15a. The predetermined mass at which the weighing device 15a weighs the piece of paper C is, for example, several grams to several tens of grams.

[0020] The feeding mechanism may be a known technique such as a vibrating feeder, etc. The feeding mechanism may be included in the weighing device 15a.

[0021] The weighing and supply of the pieces of paper C in the constant quantity supply unit 15 is a batch process. That is, the supply of the pieces of paper C from the constant quantity supply unit 15 to the junction 17 is carried out intermittently. The constant quantity supply unit 15 may have multiple weighing devices 15a, and the multiple weighing devices 15a may be operated at staggered times to improve weighing efficiency.

[0022] At the confluence 17, the pieces of paper C supplied from the constant quantity supply unit 15 are combined with the fine fragments of the slit pieces S supplied from the shredding unit 86 and mixed together. The slit pieces S and the shredding unit 86 will be described later. The pieces of paper C mixed with the fine fragments flow from the confluence 17 into the pipe 21.

[0023] The pipe 21 transports the paper pieces C from the first unit group 101 to the second unit group 102 by an air current generated by a blower (not shown).

[0024] The second unit group 102 includes a defibrating unit 30, which is a dry type defibrator, a separating unit 41, piping 23, a mixing unit 45, and piping 24. In the second unit group 102, these components are arranged in the above order from upstream to downstream. The second unit group 102 also includes a control unit 5, a collecting unit 95, a compressor 97, a power supply unit 99, and piping 25 and airflow piping 29 connected to the separating unit 41.

[0025] The paper pieces C transported through the pipe 21 flow into the defibrating unit 30. The defibrating unit 30 dry-defibrates the paper pieces C, which are a material containing fibers, to generate defibrated material containing fibers. A known defibrating mechanism can be applied to the defibrating unit 30. In this embodiment, a defibrating mechanism equipped with rotary blades is used as the defibrating unit 30. The defibrating mechanism shreds and defibrates the paper pieces C with the rotary blades to generate fibers.

[0026] The defibrating unit 30 untangles the tangled fibers contained in the paper pieces C, turning them into defibrated material containing fibers, and the defibrated material is transported to the separating unit 41.

[0027] The separation unit 41 separates the defibrated fibers. More specifically, the separation unit 41 removes components contained in the fibers that are unnecessary for manufacturing the sheet P3. The separation unit 41 separates relatively long fibers from relatively short fibers. Relatively short fibers may reduce the strength of the sheet P3, so they are selected and removed by the separation unit 41. The separation unit 41 also removes impurities such as coloring materials and additives contained in the pieces of paper C.

[0028] A known separation mechanism can be applied to the separation unit 41. In this embodiment, a disk-type separation mechanism equipped with a separation filter is used as the separation unit 41. The separation mechanism sorts and separates relatively short fibers and impurities that pass through the separation filter from relatively long fibers that do not pass through the separation filter. The relatively long fibers are used as material for the web W as defibrated fibers.

[0029] Humidified air is supplied to the inside of the separation section 41 from the second humidifying section 266 of the third unit group 103.

[0030] The defibrated fibers are removed from the separating section 41 by relatively short fibers. Then, the fibers are transported to the mixing section 45 via the piping 23 by an airflow generated by a blower (not shown) located at the tip of the airflow piping 29. Unwanted materials such as relatively short fibers and impurities are sucked into a suction device (not shown) of the collecting section 95 and discharged from the piping 25 to the collecting section 95.

[0031] The mixer 45 mixes the defibrated material, which is fiber, with a binder and the like in the air. Although not shown, the mixer 45 includes a flow path for transporting the fiber, a fan, a hopper, a supply pipe, and a valve.

[0032] The hopper is connected to the fiber flow path via a supply pipe. A valve is provided in the supply pipe between the hopper and the flow path. The hopper supplies a binder such as starch into the flow path. The valve adjusts the mass of the binder supplied from the hopper to the flow path, thereby adjusting the mixing ratio of the fiber and the binder.

[0033] The mixing section 45 may have a similar configuration for supplying coloring materials, additives, etc. in addition to the above-described configuration for supplying the binder.

[0034] The fan of the mixer 45 generates an airflow that transports the defibrated material downstream while mixing the binder and other materials into the air. The defibrated material then flows from the mixer 45 into the piping 24.

[0035] The collection unit 95 includes a filter (not shown) that filters out unnecessary particles such as relatively short fibers carried through the pipe 25 by the air current.

[0036] The compressor 97 generates compressed air. The filter may become clogged with fine particles from unwanted matter. The compressed air generated by the compressor 97 can be blown onto the filter to blow away any particles adhering to the filter, cleaning the filter.

[0037] The power supply unit 99 has a power supply device (not shown) that supplies power to the sheet manufacturing apparatus 1, and a control unit 5. The power supply unit 99 distributes power supplied from an external source to each component of the sheet manufacturing apparatus 1.

[0038] The control unit 5 is electrically connected to each component of the sheet manufacturing apparatus 1 and comprehensively controls the operation of the sheet manufacturing apparatus 1. Although not shown, the control unit 5 includes a central processing unit (CPU) and a storage unit including a random access memory (RAM) and a read-only memory (ROM). The storage unit stores various programs for controlling the sheet manufacturing apparatus 1. The control unit 5 may include dedicated hardware (application-specific integrated circuit: ASIC) that executes at least some of the various processes. In other words, the control unit 5 may be configured as a circuit including one or more processors that operate according to a computer program (software), one or more dedicated hardware circuits such as ASIC, or a combination of these.

[0039] A processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to perform processes. Memory, i.e., computer-readable media, includes anything that can be accessed by a general-purpose or special-purpose computer.

[0040] The third unit group 103 deposits and compresses defibrated material containing a binder, and forms it into a band-shaped sheet P1. The third unit group 103 includes a depositing section 50, a conveying section 60, a collecting section 96, a first humidifying section 265, a second humidifying section 266, a draining section 268, a forming section 70, and a sheet conveying section 63. In the third unit group 103, the depositing section 50, the conveying section 60, and the forming section 70 are arranged in the above order from upstream to downstream. That is, the conveying section 60 is arranged between the depositing section 50 and the forming section 70.

[0041] The conveying section 60 has a deposition conveying section 61 and a back surface conveying section 62. The conveying section 60 conveys the web W formed in the deposition section 50 to the downstream forming section 70. In the conveying direction of the web W, the deposition conveying section 61 is disposed upstream of the back surface conveying section 62. A downstream portion of the deposition conveying section 61 and an upstream portion of the back surface conveying section 62 face each other in the vertical direction. The collecting section 96 is disposed corresponding to the downstream end of the deposition conveying section 61. The first humidifying section 265 is disposed below the back surface conveying section 62.

[0042] The deposition unit 50 deposits the defibrated material containing a binder and the like by airflow and gravity to form a web W. The deposition unit 50 has a drum member 53, blade members 55 installed inside the drum member 53, a housing 51 that houses the drum member 53, and a suction unit 59. The defibrated material is taken into the drum member 53 from the piping 24.

[0043] The deposition and transport unit 61 is disposed below the deposition unit 50. The deposition and transport unit 61 has a mesh belt 611 and five tension rollers (not shown) that tension the mesh belt 611. The suction unit 59 faces the drum member 53 in the direction along the Z axis, with the mesh belt 611 sandwiched therebetween.

[0044] The blade members 55 are located inside the drum member 53 and are driven to rotate by an electric motor (not shown). The drum member 53 is a semi-cylindrical sieve. A mesh functioning as a sieve is provided on the downward-facing side of the drum member 53. The drum member 53 allows particles such as defibrated material fibers and binders that are smaller than the mesh size of the sieve to pass from the inside to the outside.

[0045] The defibrated material is agitated by the rotating blade members 55 inside the drum member 53 and is then released to the outside of the drum member 53. Humidified air is supplied to the inside of the drum member 53 from the second humidifying section 266.

[0046] The suction unit 59 is located below the drum member 53. The suction unit 59 sucks air inside the housing 51 through multiple holes in the mesh belt 611. This generates an air current that deposits the defibrated material on the mesh belt 611. The multiple holes in the mesh belt 611 allow air to pass through but do not allow fibers and binders contained in the defibrated material to pass through easily. As a result, the defibrated material released to the outside of the drum member 53 is sucked downward together with the air. The suction unit 59 is a known suction device such as a suction fan.

[0047] The defibrated material containing the binder and the like is dispersed in the air inside the housing 51 and is deposited on the upper surface of the mesh belt 611 by gravity and the airflow generated by the suction part 59 to become the web W.

[0048] The mesh belt 611 of the deposition and transport unit 61 is an endless belt that is stretched over four tension rollers. The mesh belt 611 rotates counterclockwise in FIG. 1 due to the rotation of the tension rollers. As a result, the defibrated material is continuously deposited on the mesh belt 611, and a web W is formed. The web W contains a relatively large amount of air and is soft and inflated. The deposition and transport unit 61 transports the formed web W downstream by the rotation of the mesh belt 611.

[0049] The back conveying unit 62 is located downstream of the deposition conveying unit 61 and conveys the web W handed over from the deposition conveying unit 61. The back conveying unit 62 peels the web W from the upper surface of the mesh belt 611 and conveys the web W toward the forming unit 70. The back conveying unit 62 is located above the conveyance path of the web W and is disposed slightly upstream of the starting point of the return side of the mesh belt 611, i.e., the end in the -Y direction. The +Y direction of the back conveying unit 62 and the -Y direction of the mesh belt 611 partially overlap in the vertical direction.

[0050] The rear conveying section 62 has a belt section 621, four tension rollers (not shown), and an adsorption section 623. The belt section 621 has a plurality of holes for allowing air to pass through. The belt section 621 is stretched by the four tension rollers, and rotates clockwise in FIG. 1 as the tension rollers rotate.

[0051] The suction section 623 sucks air through a plurality of holes in the belt section 621, and causes the web W to be suctioned to the belt section 621. The web W is suctioned to the belt section 621 and transported.

[0052] The suction unit 623 is located on the transport path of the web W in the rear transport unit 62, and is disposed above the belt unit 621. The suction unit 623 sucks air upward from below through multiple holes in the belt unit 621. As a result, the upper surface of the web W is adsorbed to the lower surface of the belt unit 621. When the belt unit 621 rotates in this state, the web W is adsorbed to the belt unit 621 and transported downstream. In other words, the belt unit 621 contacts the upper surface of the web W to transport the web W. The suction unit 623 is a known suction device such as a suction fan.

[0053] The recovery unit 96 recovers a part of the in-process web W when stopping the operation of the sheet manufacturing apparatus 1. Details of the recovery unit 96 and the back surface conveying unit 62 including the suction unit 623 will be described later.

[0054] The first humidifying section 265 humidifies the web W. The first humidifying section 265 is, for example, a mist humidifier. The first humidifying section 265 humidifies the web W by supplying mist M from below the web W transported by the rear conveying section 62. The first humidifying section 265 is disposed below the rear conveying section 62 and faces the web W transported by the rear conveying section 62 in the vertical direction. A known humidifying device, for example, an ultrasonic type, can be used as the first humidifying section 265.

[0055] By humidifying the web W with the mist M, the function of the binder contained in the web W is promoted, and the strength of the sheet P3 is improved. In addition, since the web W is humidified from below, droplets from the mist M are less likely to fall onto the web W. Furthermore, since the web W is humidified from the opposite side of the upper surface that contacts the belt portion 621, sticking of the web W to the belt portion 621 is reduced.

[0056] The forming unit 70 compresses the web W and forms it into a strip-shaped sheet P1. The forming unit 70 has a pair of a first roller 71 and a second roller 72. The forming unit 70 passes the web W between the first roller 71 and the second roller 72 to form the strip-shaped sheet P1 from the web W.

[0057] Each of the first roller 71 and the second roller 72 is a substantially cylindrical member. The rotation axis of the first roller 71 and the rotation axis of the second roller 72 are aligned along the X-axis. The first roller 71 is disposed substantially below the transport path of the web W, and the second roller 72 is disposed substantially above it. The first roller 71 and the second roller 72 rotate close to each other while the strip-shaped sheet P1 is being formed from the web W.

[0058] 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, i.e., the width of the web W. Therefore, the web W is firmly sandwiched between the first roller 71 and the second roller 72.

[0059] 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 not less than 110 mm and not more than 150 mm, and the diameter of the second roller 72 is not less than 80 mm and not more than 110 mm.

[0060] The first roller 71 includes, for example, a core and a surface layer covering the core. The core may have a hollow structure made of aluminum, iron, stainless steel, or the like. Materials for the surface layer include fluororesins such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and ETFE (tetrafluoroethylene-ethylene copolymer), as well as silicone resin. This improves the releasability of the first roller 71 from the web W. It also reduces wear and damage to the core.

[0061] The second roller 72 includes, for example, a core, an intermediate layer, and a surface layer. The core may have a hollow structure made of aluminum, iron, stainless steel, or the like. The intermediate layer covers the core and is also covered by the surface layer. In other words, the intermediate layer is interposed between the core and the surface layer.

[0062] Materials for the intermediate layer include elastomers such as silicone rubber and urethane rubber. The hardness of the elastomer, as measured by an Asker C hardness tester, is preferably 30 to 70, more preferably 40 to 60. The thickness of the intermediate layer is preferably 1 mm to 10 mm, more preferably 1 mm to 5 mm.

[0063] Examples of materials for the surface layer include fluororesins such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and ETFE (tetrafluoroethylene-ethylene copolymer).

[0064] The second roller 72 having the above-described configuration improves the releasability of the second roller 72 from the web W. In addition, wear and damage to the intermediate layer are suppressed.

[0065] The web W is pressed while 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 or less, and even more preferably 0.4 MPa or more and 8.0 MPa or less. This suppresses deterioration of the fibers in the web W.

[0066] The first roller 71 has a built-in electric heater and has the function of raising the temperature of the roller surface. Similarly to the first roller 71, the second roller 72 also preferably has a function of raising the temperature of the roller surface by an electric heater.

[0067] The surface temperature of the first roller 71, i.e., the temperature of the surface layer of the first roller 71 that comes into contact with the web W, is preferably 100°C or higher and 130°C or lower. The surface temperature of the second roller 72, i.e., the temperature of the surface layer of the second roller 72 that comes into contact with the web W, is preferably 80°C or higher and 100°C or lower.

[0068] The first roller 71 is rotated by a stepping motor (not shown). The second roller 72 is not driven by an electric motor or the like, but is a driven roller that rotates in conjunction with the rotation of 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.

[0069] The web W is sandwiched between the first roller 71 and the second roller 72 and sent downstream while being heated and pressurized. That is, the web W is continuously passed through the forming unit 70 and 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 is efficiently heated and pressurized.

[0070] As the web W passes through the forming unit 70, it is converted from a soft state containing a relatively large amount of air into a reduced amount of air and an increased density. Then, the fibers are bound together by a binder, and the web W is formed into a belt-shaped sheet P1. The belt-shaped sheet P1 is transported to the first unit group 101 by a plurality of rollers (not shown) of the sheet transport unit 63.

[0071] The second humidifier 266 is disposed below the first humidifier 265. A known evaporation type humidifier can be applied to the second humidifier 266.

[0072] The second humidifying section 266 humidifies a predetermined area of ​​the sheet manufacturing apparatus 1. The predetermined area is one or more of the buffer tank 13, the separation section 41, and the drum member 53 of the accumulation section 50. Specifically, humidified air is supplied to the above-mentioned area from the second humidifying section 266 through multiple pipes (not shown). The humidified air suppresses the electrostatic charge of paper chips C, fibers, etc. in each of the above-mentioned components. This makes it difficult for paper chips C, fibers, etc. to adhere to each component.

[0073] The drainage unit 268 is a drainage tank. The drainage unit 268 is used in the first humidifying unit 265, the second humidifying unit 266, etc., and collects and stores old water. The drainage unit 268 can be removed from the sheet manufacturing apparatus 1 as needed, allowing the accumulated water to be discarded.

[0074] The strip-shaped sheet P1 transported from the forming section 70 to the first unit group 101 reaches the first cutting section 81. The first cutting section 81 cuts the strip-shaped sheet P1 in a direction intersecting the transport direction, for example, along the X-axis. The strip-shaped sheet P1 is cut into single sheets P2 at the first cutting section 81. The single sheets P2 are transported from the first cutting section 81 to the second cutting section 82 by the sheet transport section 63.

[0075] The second cutting section 82 cuts the single sheet P2 in the conveying direction, for example, along the Y axis. More specifically, the second cutting section 82 cuts both ends of the single sheet P2 in the direction along the X axis. This cuts the single sheet P2 into sheets P3 of a predetermined shape, such as A4 size or A3 size.

[0076] When the second cutting section 82 cuts the single sheets P2 into sheets P3, slit pieces S, which are scraps, are generated. The slit pieces S are transported in the approximately -Y direction to the shredding section 86, which is a shredder. The shredding section 86 shreds the slit pieces S into small pieces and supplies them to the junction 17. A mechanism may be installed between the shredding section 86 and the junction 17 to weigh the small pieces of the slit pieces S and supply them to the junction 17.

[0077] The sheet P3 is conveyed substantially upward and accumulated on the tray 84. In this manner, the sheet P3 is manufactured by the sheet manufacturing apparatus 1. The sheet P3 can be used as a substitute for, for example, copy paper.

[0078] 2, the suction unit 623 of the conveying unit 60 includes a first suction unit 623a, a second suction unit 623b, and a third suction unit 623c. In the suction unit 623, the first suction unit 623a, the second suction unit 623b, and the third suction unit 623c are arranged in this order in the -Y direction, which is the conveying direction of the web W. The first suction unit 623a, the second suction unit 623b, and the third suction unit 623c each have an independent suction device, and can be individually switched between operating and stopped.

[0079] The first suction portion 623a is positioned vertically substantially opposite to the starting point of the return side of the mesh belt 611 of the deposition and conveyance portion 61. The first suction portion 623a adsorbs the web W conveyed by the deposition and conveyance portion 61 onto the belt portion 621, and receives the web W from the deposition and conveyance portion 61.

[0080] The second suction portion 623b is disposed above the first humidifying portion 265. Like the first suction portion 623a, the second suction portion 623b adsorbs the web W to the belt portion 621, and also sucks the mist M generated by the first humidifying portion 265 upward to impregnate the web W.

[0081] The third suction portion 623c, like the first suction portion 623a, suctions the web W onto the belt portion 621, and conveys the web W to the forming portion 70 downstream.

[0082] The first suction portion 623a, the second suction portion 623b, and the third suction portion 623c each continue to perform a suction operation during normal operation when the sheet manufacturing apparatus 1 manufactures the sheet P3. The air sucked by the first suction portion 623a, the second suction portion 623b, and the third suction portion 623c is introduced into the above-mentioned collection portion 95 via a pipe (not shown). In the following description, the operation when the sheet manufacturing apparatus 1 manufactures the sheet P3 may also be simply referred to as normal operation.

[0083] Although not shown, the rear conveying section 62 has a lifting mechanism that raises and lowers the conveying path of the web W in the rear conveying section 62. Specifically, the lifting mechanism raises and lowers the belt section 621, four tension rollers (not shown), and the suction section 623 in the vertical direction. Fig. 2 shows the state during normal operation of the sheet manufacturing apparatus 1. During normal operation, the lifting mechanism lowers each component of the rear conveying section 62 to its lowest position.

[0084] In normal operation, the transport path of the web W from the stacking and conveying section 61 to the back surface conveying section 62 is continuous along the Y axis and is substantially linear. In contrast, when the lifting mechanism raises each component of the back surface conveying section 62, the transport path of the web W becomes discontinuous with a step between the stacking and conveying section 61 and the back surface conveying section 62. The action of the lifting mechanism when lifting each component of the back surface conveying section 62 will be described later. Known devices such as electric motors and various actuators can be used as the drive source of the lifting mechanism.

[0085] The recovery unit 96 is disposed below the region including the starting point of the return side of the mesh belt 611 of the deposition and conveyance unit 61, i.e., the end in the -Y direction. When the normal operation of the sheet manufacturing apparatus 1 is stopped, a portion of the web W falls into the recovery unit 96 and is recovered as indicated by the dashed arrow. The recovered portion of the web W is stored in a recovery container (not shown).

[0086] The control unit 5 has a sensor 91. The sensor 91 includes a first sensor 91a, a second sensor 91b, and a third sensor 91c. Each of the first sensor 91a and the second sensor 91b is disposed on the transport path of the web W and detects the presence or absence of the web W in a detection area. The third sensor 91c is disposed on the transport path of the strip-shaped sheet P1 and detects the presence or absence of the strip-shaped sheet P1 in a corresponding area. The first sensor 91a is an example of a sensor unit of the present invention.

[0087] The first sensor 91a is disposed above the transport path of the web W and upstream of the back transport unit 62 in the transport direction of the web W. The second sensor 91b is disposed below the transport path of the web W and downstream of the third suction unit 623c in the transport direction of the web W. The third sensor 91c is disposed above the transport path of the strip-shaped sheet P1 and downstream of the forming unit 70 in the transport path of the strip-shaped sheet P1.

[0088] The first sensor 91a, the second sensor 91b, and the third sensor 91c are not particularly limited as long as they can detect the presence or absence of the web W or the strip-shaped sheet P1. Known sensors such as photo sensors can be used as the first sensor 91a, the second sensor 91b, and the third sensor 91c.

[0089] The detection results of the first sensor 91a, the second sensor 91b, and the third sensor 91c are transmitted to the CPU of the control unit 5 and reflected in various controls of the sheet manufacturing apparatus 1. In particular, the detection result of the first sensor 91a is used for control when stopping the operation of the sheet manufacturing apparatus 1, which will be described later.

[0090] As shown in Fig. 3, the sheet manufacturing method according to this embodiment includes steps S1 to S6. The sheet manufacturing method according to this embodiment is a method for stopping normal operation of the sheet manufacturing apparatus 1 among methods for manufacturing a sheet P3 using the sheet manufacturing apparatus 1. Known manufacturing methods can be applied to methods other than those described above. Note that the sheet manufacturing method according to this embodiment is an example and is not limited to this.

[0091] When the normal operation of the sheet manufacturing apparatus 1 is stopped, step S1 is first performed. In step S1, the supply of defibrated material, which is the material for the web W, is stopped. In step S2, the web W is broken into an upstream web W1 and a downstream web W2, which will be described later. In step S3, it is determined whether the broken area of ​​the web W has passed the first sensor 91a. If the broken area has passed, the process proceeds to step S4. In step S4, the lifting mechanism is raised. In step S5, a sheet P3 is manufactured using the downstream web W2. In step S6, the upstream web W1 is collected in the collection section 96.

[0092] Next, details of steps S1 to S6 will be explained with reference to Fig. 4 to Fig. 7. As shown in Fig. 4, in step S1, the control unit 5 stops the supply of defibrated material from the piping 24 to the deposition unit 50. The deposition unit 50 continues to operate until all the defibrated material in the drum member 53 is gone. The deposition unit 50 stops, for example, after a certain amount of time has passed since the supply of defibrated material was stopped. Then, the process proceeds to step S2.

[0093] In step S2, the control unit 5 controls the deposition and conveyance unit 61 of the conveyance unit 60 to break the web W into the upstream web W1 and the downstream web W2 between the deposition and conveyance unit 61 and the back surface conveyance unit 62. Specifically, the control unit 5 stops driving the mesh belt 611 to stop the deposition and conveyance unit 61 from conveying the web W. At the same time, the control unit 5 causes the back surface conveyance unit 62 to continue conveying the web W.

[0094] At this time, the web W is subjected to a force held by the stopped mesh belt 611 and a force pulling the web W in the -Y direction by the back conveying section 62. The web W is torn by the force and broken into the upstream web W1 and the downstream web W2. Then, the process proceeds to step S3.

[0095] In step S3, the control unit 5 determines whether the break region of the web W has passed the first sensor 91a. Specifically, the first sensor 91a detects the gap between the upstream web W1 and the downstream web W2, which is the break region of the web W. In other words, the downstream web W2 is transported to the back surface transport unit 62 and transported in the -Y direction, and when the end of the downstream web W2 in the +Y direction passes, the first sensor 91a detects that the web W is absent. The back surface transport unit 62 continues transporting the downstream web W2.

[0096] As shown in FIG. 5, when the +Y direction end of the downstream web W2 passes below the first sensor 91a, the process proceeds to step S4.

[0097] In step S4, as shown in FIG. 6, the control unit 5 raises the lifting mechanism of the back surface conveying unit 62. The back surface conveying unit 62 is raised, for example, by several millimeters from its normal operating position. This creates a step in the conveyance path of the web W between the stacking / conveying unit 61 and the back surface conveying unit 62. At this time, the suction of the first suction unit 623a and the second suction unit 623b is stopped, while the suction of the third suction unit 623c is continued. This makes it difficult for the −Y direction end of the upstream web W1 to be adsorbed to the belt unit 621 in step S6. In step S4, the suction force of the third suction unit 623c may be increased compared to that in normal operation. Step S4 is performed after step S3, in which the web W is broken, and before step S6, in which the upstream web W1 is collected. The suction device of the collecting unit 95 continues suction until the sheet manufacturing apparatus 1 completely stops. Then, the process proceeds to step S5.

[0098] In step S5, as shown in FIG. 7, the control unit 5 transports the downstream web W2 to the forming unit 70, where the downstream web W2 continues to form a strip-shaped sheet P1. The control unit 5 stops the operation of the back surface conveying unit 62 after the upstream end of the downstream web W2 passes the second sensor 91b. The control unit 5 also stops the operation of the forming unit 70 after the upstream end of the strip-shaped sheet P1 formed from the downstream web W2 passes the third sensor 91c. The process then proceeds to step S6. Note that steps S5 and S6 may be performed in parallel. FIG. 7 shows the operations of step S6 in addition to the operations of step S5.

[0099] In step S6, the deposition and conveyance unit 61 is restarted to recover the upstream web W1 in the recovery unit 96. Specifically, the upstream web W1 is conveyed in the -Y direction. In step S5, the conveyance path of the web W is shifted upward, so the upstream web W1 is not transferred from the deposition and conveyance unit 61 to the backside conveyance unit 62. Therefore, the downstream end of the upstream web W1 sags due to gravity, is further conveyed to the deposition and conveyance unit 61, and falls into the recovery unit 96 to be recovered.

[0100] In step S6, the upstream web W1 begins to be conveyed, and the first sensor 91a eventually detects the upstream web W1. As the upstream web W1 continues to be collected in the collection unit 96, the upstream end of the upstream web W1, i.e., the end in the +Y direction, passes through the detection range of the first sensor 91a. This causes the first sensor 91a to detect that the upstream web W1 has disappeared from the stacking / transporting unit 61 and has been completely collected in the collection unit 96. The control unit 5 stops the operation of the stacking / transporting unit 61 based on the detection result of the first sensor 91a that collection of the upstream web W1 has been completed.

[0101] The control unit 5 is not limited to stopping the normal operation of the sheet manufacturing apparatus 1 based on the detection results of the first sensor 91a, the second sensor 91b, and the third sensor 91c. The control unit 5 may also proceed with the above steps under timer management. As a result, the control unit 5 stops the operation of the accumulation unit 50, the accumulation and conveyance unit 61 and the back surface conveyance unit 62 of the conveyance unit 60, and the forming unit 70.

[0102] According to this embodiment, the following effects can be obtained.

[0103] When normal operation is stopped, the web W is not left behind, and the time required until stopping can be shortened. Specifically, the web W is broken during the stopping operation, the upstream web W1 is collected in the collection section 96, and the downstream web W2 is flowed and processed into the sheet P3. Therefore, the time required until the sheet manufacturing apparatus 1 completely stops is shortened compared to when all of the in-process webs W at the time of stopping are processed into the sheet P3. Therefore, it is possible to provide a sheet manufacturing apparatus 1 and a sheet manufacturing method using the sheet manufacturing apparatus 1 that do not leave the web W behind when stopping and shorten the time required until stopping. [Explanation of symbols]

[0104] 1...sheet manufacturing apparatus, 5...control section, 30...defibrating section, 50...deposition section, 60...conveying section, 61...deposition and conveying section, 62...back conveying section, 70...forming section, 91a...first sensor as sensor section, 96...recovery section, 621...belt section, 623...adsorption section, P1...strip-shaped sheet, P3...sheet, W...web, W1...upstream web, W2...downstream web.

Claims

1. A sheet manufacturing apparatus for manufacturing a sheet from a material containing fiber, a defibrating unit that defibrates the material to generate a defibrated material; a depositing section that deposits the defibrated material to form a web; a forming section that compresses the web and forms it into the sheet; a conveying section disposed between the depositing section and the forming section, the conveying section having a depositing conveying section and a back conveying section for conveying the web; a recovery unit disposed corresponding to the deposition and transport unit; a control unit that controls the operation of the sheet manufacturing apparatus, the deposition conveying section is disposed upstream of the back conveying section in the conveying direction of the web, When the control unit stops the operation of the sheet manufacturing apparatus, The conveying section is controlled to break the web into an upstream web and a downstream web between the stacking and conveying section and the backside conveying section, The sheet manufacturing apparatus comprises recovering the upstream web in the recovery section and forming the downstream web into the sheet.

2. The rear transport unit is a belt portion on which the web is adsorbed and transported; an adsorption portion that adsorbs the web to the belt portion, 2. The sheet manufacturing apparatus according to claim 1, wherein, when the operation of the sheet manufacturing apparatus is stopped, the control unit stops the transport of the web by the stacking transport unit and continues the transport of the web by the back transport unit to break the web.

3. The control unit a sensor unit disposed upstream of the back surface conveying unit in the conveying direction of the web, the sensor unit detecting that the upstream web has been completely collected in the collecting unit; The sheet manufacturing apparatus according to claim 1 , wherein the operation of the stacking and conveying unit is stopped based on a detection result of the sensor unit.

4. a defibrator unit that defibrates a fiber-containing material to generate defibrated material; a depositing section that deposits the defibrated material to form a web; a forming section for compressing the web into a sheet; a conveying section disposed between the depositing section and the forming section, the conveying section having a depositing conveying section and a back conveying section for conveying the web; a recovery unit disposed corresponding to the deposition and transport unit; A sheet manufacturing method using a sheet manufacturing apparatus including a control unit that controls operation of the sheet manufacturing apparatus, When the operation of the sheet manufacturing apparatus is stopped, stopping the transport of the web by the deposition and conveyance unit and continuing the transport of the web by the backside conveyance unit, and breaking the web into an upstream web and a downstream web between the deposition and conveyance unit and the backside conveyance unit; conveying the downstream web to the forming section to produce the sheet from the downstream web; restarting the depositing and conveying section to recover the upstream web into the recovery section.

5. the rear transport section has a lifting mechanism for raising and lowering the transport path of the web, The sheet manufacturing method according to claim 4 , further comprising the step of raising the lifting mechanism after the step of breaking the web and before the step of recovering the upstream web.

Images