Thin sheet manufacturing apparatus

Abstract

This invention provides a sheet manufacturing apparatus for homogenizing the in-plane moisture content of a sheet. The sheet manufacturing apparatus manufactures sheets from a fibrous material and includes: an accumulation section that accumulates the fibrous material by an airflow to form a sheet; a sheet conveying section having a conveyor belt that contacts and holds one side of the sheet; a humidification section disposed opposite to one side of the conveyor belt and supplying moisture from the other side of the sheet; and a suction section disposed opposite to the humidification section across the conveyor belt, the suction section having a plurality of suction ports for suctioning air, the humidification section having an outlet for discharging humidified air, and a first suction port and the outlet being arranged facing each other.

Description

Technical Field

[0001] This invention relates to a sheet manufacturing apparatus. Background Technology

[0002] As shown in Patent Document 1, a sheet manufacturing apparatus is known to include: an accumulation section for accumulating fibrous material on a mesh belt to form a sheet; a humidification section disposed downstream of the accumulation section in the sheet conveying direction for humidifying the sheet; a conveying section disposed downstream of the humidification section in the sheet conveying direction for conveying the sheet downstream while peeling it off the mesh belt; and a pressure roller disposed downstream of the conveying section in the sheet conveying direction for applying pressure to the sheet.

[0003] However, in the aforementioned sheet manufacturing apparatus, while humidifying one side of the sheet composed of stacked fibers through a humidification section, the sheet is conveyed downstream. At this time, the airflow of humidifying air discharged from the humidification section sometimes becomes unstable, resulting in uneven moisture content in the in-plane direction of the sheet depending on the location. Consequently, a problem arises where in-plane strength deviations occur in the sheet, making it impossible to ensure sheet quality.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-44284 Summary of the Invention

[0005] A sheet manufacturing apparatus manufactures sheets from a fibrous material and includes: a stacking section that stacks the fibrous material by airflow to form a sheet; a sheet conveying section having a conveyor belt that contacts and holds one side of the sheet; a humidifying section disposed opposite to one side of the conveyor belt and supplying moisture from the other side of the sheet; and a suction section disposed opposite to the humidifying section across the conveyor belt, the suction section having a plurality of suction ports for suctioning air, the humidifying section having an outlet for discharging humidified air, and a first suction port of the plurality of suction ports and the outlet being arranged facing each other. Attached Figure Description

[0006] Figure 1 This is a schematic diagram illustrating the structure of a sheet manufacturing apparatus.

[0007] Figure 2 This is a magnified view showing the surrounding structure of the sheet conveying section.

[0008] Figure 3 This is a diagram showing the sheet conveying section and the air jet section viewed in the +Z direction.

[0009] Figure 4 This is a diagram showing the humidifier section as observed in the -Z direction.

[0010] Figure 5A This is a schematic diagram illustrating the function of the sheet conveying section and the air jet section.

[0011] Figure 5B This is a schematic diagram illustrating the function of the sheet conveying section and the air jet section.

[0012] Figure 5C This is a schematic diagram illustrating the function of the sheet conveying section and the air jet section. Detailed Implementation

[0013] First, the structure of the sheet manufacturing apparatus 1 will be described. The sheet manufacturing apparatus 1 is an apparatus for forming sheet S.

[0014] like Figure 1 As shown, the sheet manufacturing apparatus 1 includes, for example, a feeding unit 10, a coarse crushing unit 11, a fiber unwinding unit 20, a screening unit 40, a first sheet forming unit 45, a rotating body 49, a mixing unit 50, a stacking unit 60, a sheet conveying unit 80, a humidifying unit 90, an air jetting unit 100, a sheet forming unit 110, and a cutting unit 120. Furthermore, the sheet manufacturing apparatus 1 includes a control unit (processor) that controls the drive mechanisms of each of the above-mentioned parts.

[0015] The supply unit 10 supplies raw materials to the coarse crushing unit 11. The supply unit 10 is, for example, an automatic feeding unit for continuously feeding raw materials into the coarse crushing unit 11. The raw materials supplied by the supply unit 10 are materials containing various fibers.

[0016] As a fiber, it is not particularly limited and a wide range of fiber materials can be used. Examples of fibers include natural fibers (animal fibers, plant fibers) and chemical fibers (organic fibers, inorganic fibers, organic-inorganic composite fibers). More specifically, fibers can be listed as those composed of cellulose, silk, wool, cotton, hemp, kenaf, flax, ramie, jute, Manila hemp, sisal, coniferous trees, broad-leaved trees, etc., and these fibers can be used alone, appropriately blended, or as regenerated fibers that have undergone refining.

[0017] Raw materials for fibers include, for example, pulp, waste paper, and old cloth. Furthermore, fibers can undergo various surface treatments. In addition, fibers can be pure materials or materials containing impurities and other components. Furthermore, fibers can also be obtained by dry defibering of waste paper or pulp sheets.

[0018] Although the length of the fiber is not particularly limited, in an individual fiber, the length along the length direction of the fiber is more than 1 μm and less than 5 mm, preferably more than 2 μm and less than 3 mm, and more preferably more than 3 μm and less than 2 mm.

[0019] In the sheet manufacturing apparatus 1, since moisture is supplied at the humidification section 90, the mechanical strength of the formed sheet S can be improved when a fiber capable of forming hydrogen bonds is used. Cellulose is an example of such a fiber.

[0020] The fiber content in the sheet S is, for example, 50% by mass or more and 99.9% by mass or less, preferably 60% by mass or more and 99% by mass or less, and more preferably 70% by mass or more and 99% by mass or less. Such a content can be achieved by blending during the formation of the mixture.

[0021] The coarse shredder 11 cuts the raw material supplied by the supply section 10 into fragments in an atmosphere or similar gas. The fragments are, for example, a few centimeters square. In the illustrated example, the coarse shredder 11 has coarse shredding blades 12, which can cut the input raw material. For example, a paper shredder is used as the coarse shredder 11. The raw material cut by the coarse shredder 11 is received by the hopper 14 and then transferred to the debonding section 20 via the pipe 15.

[0022] The defiberization section 20 defibers the raw material that has been cut by the coarse crushing section 11. Here, "defiberization" means separating the raw material, which is composed of multiple fibers bonded together, into individual fibers. The defiberization section 20 also has the function of separating resin particles, inks, pigments, anti-seepage agents, and other substances adhering to the raw material from the fibers.

[0023] The substance passing through the defiber section 20 is called "defiber material". The "defiber material" may contain, in addition to the disassembled fibers, resin particles, inks, colorants such as pigments, or additives such as anti-bleeding materials and paper strength enhancers separated from the fibers during the disassembly process. The disassembled defiber material is rope-like in shape. The disassembled defiber material can exist either independently, without intertwining with other disassembled fibers, or in a clump-like state, intertwined with other disassembled defiber material.

[0024] The defiber section 20 performs defibering in a dry manner. Here, the method of performing defibering and other processes in a gaseous environment such as the atmosphere, rather than in a liquid, is referred to as dry. For example, an impeller mill is used as the defiber section 20. The defiber section 20 has the function of generating an airflow that draws in the raw material and discharges the defibered material. Thus, the defiber section 20 can draw in the raw material and airflow together from the inlet 22 using its own generated airflow, perform defibering, and then transport the defibered material to the outlet 24. The defibered material passing through the defiber section 20 is transferred to the screening section 40 via the pipe 16. Furthermore, the airflow used to transport the defibered material from the defiber section 20 to the screening section 40 can utilize the airflow generated by the defiber section 20, or it can utilize the airflow from an airflow generating device such as a blower.

[0025] The screening section 40 introduces the defibered material, which has been defibered by the defibering section 20, through the inlet 42 and performs screening based on the length of the fibers. The screening section 40 includes, for example, a roller section 41 and a housing section 43 for housing the roller section 41. The roller section 41 is, for example, a sieve. The roller section 41 has a mesh and is capable of separating fibers or particles smaller than the mesh size (i.e., the first screening material that passes through the mesh) from fibers or particles larger than the mesh size (i.e., the second screening material that does not pass through the mesh). For example, the first screening material is conveyed to the accumulation section 60 via the pipe 17. The second screening material is returned to the defibering section 20 from the outlet 44 via the pipe 18. Specifically, the roller section 41 is a sieve that is a cylinder driven by a motor. The mesh used in the roller section 41 can be, for example, a wire mesh, a porous metal mesh formed by stretching a slit metal plate, or a perforated metal mesh formed by forming holes in a metal plate using a stamping press.

[0026] The first sheet forming section 45 conveys the first screened material that has passed through the screening section 40 to the pipe 17. The first sheet forming section 45 includes, for example, a mesh belt 46, a support roller 47, and a suction mechanism 48.

[0027] The suction mechanism 48 is capable of sucking the first screened material, which has passed through the opening of the screening section 40 and been dispersed into the air, onto the mesh belt 46. The first screened material accumulates on the moving mesh belt 46 and forms a sheet V.

[0028] A first screened material passing through the opening of the screening section 40 is deposited on the mesh belt 46. The mesh belt 46 is structured such that it is supported by a support roller 47, making it difficult for the first screened material to pass through while allowing air to pass through. The mesh belt 46 moves by rotating on its own axis via the support roller 47. By continuously moving the mesh belt 46 while the first screened material passing through the screening section 40 continuously falls and accumulates, a material sheet V is formed on the mesh belt 46.

[0029] A suction mechanism 48 is disposed below the mesh belt 46. The suction mechanism 48 generates a downward airflow. Through the suction mechanism 48, the first screened material dispersed in the air by the screening section 40 can be drawn onto the mesh belt 46. As a result, the discharge velocity discharged from the screening section 40 can be increased.

[0030] The material sheet V passes through the screening section 40 and the first material sheet forming section 45, thereby being formed into an air-rich, soft, and fluffy state. The material sheet V stacked on the mesh belt 46 is fed into the pipe 17 and conveyed to the stacking section 60.

[0031] The rotating body 49 cuts the sheet V. In the illustrated example, the rotating body 49 has a base 49a and protrusions 49b extending from the base 49a. The protrusions 49b have, for example, a plate-like shape. In the illustrated example, four protrusions 49b are provided, and the four protrusions 49b are arranged at equal intervals. The protrusions 49b can rotate about the base 49a as an axis by rotating in the direction R via the base 49a. By using the rotating body 49 to cut the sheet V, the variation in the amount of fiber supplied to the stacking section 60 per unit time can be reduced, for example.

[0032] The rotating body 49 is disposed near the first sheet forming section 45. In the illustrated example, the rotating body 49 is disposed near the support roller 47a on the downstream side of the sheet V's path. The rotating body 49 is disposed at a position where the protrusion 49b can contact the sheet V, but not where the conveyor belt 46 on which the sheet V is deposited can contact. This suppresses wear on the conveyor belt 46 due to the protrusion 49b. The shortest distance between the protrusion 49b and the conveyor belt 46 is, for example, 0.05 mm or more and 0.5 mm or less. This is a distance at which the sheet V can be cut without damaging the conveyor belt 46.

[0033] The mixing section 50, for example, mixes the first screened material that has passed through the screening section 40 and the adhesive. The mixing section 50 includes, for example, an adhesive supply section 52 for supplying the adhesive, a pipe 54 for conveying the first screened material and the adhesive, and a blower 56. In the illustrated example, the adhesive is supplied from the adhesive supply section 52 to the pipe 54 via the hopper 19. The pipe 54 is connected to the pipe 17.

[0034] In the mixing section 50, an airflow is generated by a blower 56, and the first screened material and the adhesive are conveyed in the pipe 54 while being mixed. Furthermore, the mechanism for mixing the first screened material and the adhesive is not particularly limited; it can be a mechanism that uses high-speed rotating blades for stirring, or a mechanism that utilizes the rotation of a container, such as a V-type mixer.

[0035] As the adhesive supply unit 52, a screw feeder or a disc feeder is used.

[0036] The adhesive supplied from the adhesive supply section 52 is, for example, starch or dextrin. Starch is a polymer composed of multiple α-glucose molecules polymerized by glycosidic bonds. Starch can be linear or branched.

[0037] Starch can be made from a variety of plant-based materials. Examples of raw materials for starch include grains such as corn, wheat, and rice; legumes such as broad beans, mung beans, and red beans; tubers such as potatoes, sweet potatoes, and cassava; wild grasses such as ferns, bracken, and kudzu; and palm trees such as coconut palms.

[0038] In addition, processed starch and modified starch can also be used as starch. Examples of processed starch include acetylated adipic acid cross-linked starch, acetylated starch, oxidized starch, sodium octenyl succinate starch, hydroxypropyl starch, hydroxypropyl distarch phosphate, monostarch phosphate, phosphorylated distarch phosphate, urea phosphate-modified starch, sodium starch glycolate, and high-amino corn starch. Furthermore, dextrin, as a modified starch, can be appropriately used from materials obtained through starch processing or modification.

[0039] In the sheet manufacturing apparatus 1, since starch or dextrin is used as a binder, by applying moisture and then pressing and heating, at least one of the following can occur: gelatinization of the binder and generation of hydrogen bonds between fibers, thereby giving the sheet S sufficient strength. On the other hand, if the sheet S can have sufficient strength using only the hydrogen bonds between fibers, it is also possible to manufacture the sheet S without using a binder. When manufacturing the sheet S without using a binder, the sheet manufacturing apparatus 1 may not include a binder supply unit 52.

[0040] The starch or dextrin content in the sheet S is, for example, 0.1% by mass or more and 50% by mass or less, preferably 1% by mass or more and 40% by mass or less, and more preferably 1% by mass or more and 30% by mass or less. Such a content can be achieved by blending during the formation of the mixture.

[0041] In addition to the adhesive, the adhesive supply section 52 may contain, depending on the type of sheet S being manufactured, a colorant for coloring the fibers, an agglomeration inhibitor for inhibiting the agglomeration of the fibers and the adhesive, or a flame retardant for making the fibers less flammable. The mixture that has passed through the mixing section 50 is transferred to the stacking section 60 via the pipe 54.

[0042] The stacking section 60 introduces the mixture that has passed through the mixing section 50 through the inlet 62 to untangle the intertwined fibers and allow them to fall while being dispersed in the air. As a result, the stacking section 60 enables the mixture to be stacked uniformly on the second sheet forming section 70.

[0043] The accumulation section 60 includes, for example, a roller section 61 and a housing section 63 for housing the roller section 61. The roller section 61 is a rotating cylinder sieve. The roller section 61 has a mesh and allows fibers or particles smaller than the mesh size contained in the mixture that has passed through the mixing section 50 to fall off. The structure of the roller section 61 is, for example, the same as that of the roller section 41.

[0044] Furthermore, the "sieve" of the roller section 61 may not have the function of screening a specific object. That is, the "sieve" used as the roller section 61 refers to a component with a mesh, and the roller section 61 can also cause all the mixture introduced into the roller section 61 to fall down.

[0045] The stacking section 60 includes a second sheet forming section 70. The second sheet forming section 70 stacks the mixture that has passed through the stacking section 60 to form a sheet W. The second sheet forming section 70 includes, for example, a first mesh belt 72, a support roller 74, and a suction mechanism 76.

[0046] On the first mesh belt 72, a mixture passing through the opening in the accumulation section 60 is deposited. The first mesh belt 72 is structured to be supported by a support roller 74, making it difficult for the mixture to pass through while allowing air to pass. The first mesh belt 72 moves by rotating on its own axis via the support roller 74. By continuously moving the first mesh belt 72 while the mixture passing through the accumulation section 60 continuously falls and accumulates, a sheet W is formed on the first mesh belt 72.

[0047] A suction mechanism 76 is disposed below the first mesh belt 72. The suction mechanism 76 generates a downward airflow. Through the suction mechanism 76, the mixture dispersed in the air by the accumulation section 60 is drawn onto the first mesh belt 72. This increases the discharge velocity from the accumulation section 60. Furthermore, the suction mechanism 76 creates a downward airflow along the path of the mixture, thereby preventing fibers or adhesives from tangling during the descent.

[0048] As described above, by passing through the stacking section 60, a soft and fluffy sheet W is formed, which is rich in air. Furthermore, the structure of the stacking section 60 is not limited to the structure illustrated in the above embodiment, but can be applied to various fiber stacking structures used in air-laid web forming.

[0049] A sheet conveying section 80 is disposed downstream of the sheet W on the first mesh belt 72 in the conveying direction. The sheet conveying section 80 peels the sheet W off the first mesh belt 72 and conveys it toward the sheet forming section 110.

[0050] like Figure 2 As shown, the sheet conveying unit 80 includes a second mesh belt 81 as a conveyor belt, multiple rollers 82, and a suction mechanism 83 as a suction unit. The second mesh belt 81 is structured such that air passes through it, supported by the multiple rollers 82. The second mesh belt 81 is configured to be driven to rotate by the rotation of the rollers 82. The suction mechanism 83 is positioned opposite the sheet W, separated from the second mesh belt 81. The suction mechanism 83 includes suction fans 86 (in this embodiment, a first suction fan 86a, a second suction fan 86b, and a third suction fan 86c), and the suction force of the suction fans 86 generates an upward airflow on the second mesh belt 81. The sheet W is then suctioned by this airflow.

[0051] More specifically, the suction mechanism 83 has a plurality of suction ports 84 for suctioning air. In this embodiment, the suction ports 84 are configured as a first suction port 84a, a second suction port 84b, and a third suction port 84c. The second suction port 84b is arranged adjacent to the first suction port 84a in the conveying direction of the second mesh belt 81. In this embodiment, the second suction port 84b is disposed in the -Y direction of the first suction port 84a. The third suction port 84c is disposed at a position adjacent to the first suction port (in the +Y direction). That is, in this embodiment, the first suction port 84a is located between the second suction port 84b and the third suction port 84c in the conveying direction of the second mesh belt 81.

[0052] In addition, the suction mechanism 83 has a first suction pipe 85a connected to the first suction port 84a, a second suction pipe 85b connected to the second suction port 84b, and a third suction pipe 85c connected to the third suction port 84c.

[0053] The first suction pipe 85a is a flow channel divided by the wall forming the first suction port 84a. Furthermore, a first suction fan 86a is disposed on the first suction pipe 85a.

[0054] In addition, such as Figure 3 As shown, each suction port 84, when viewed along the +Z direction, is composed of an elongated plate-like component extending along the X-axis and a plurality of through holes 88 formed on the plate-like component. Driven by the first suction fan 86a, air is drawn through the plurality of through holes 88 and into the first suction pipe 85a.

[0055] The second suction pipe 85b is a flow channel divided by the wall forming the second suction port 84b. The second suction pipe 85b is arranged adjacent to the first pipe 85a in the conveying direction. Furthermore, a second suction fan 86b is disposed on the second suction pipe 85b. By driving the second suction fan 86b, air is drawn through the second suction pipe 85b from the plurality of through holes 88.

[0056] The third suction pipe 85c is a flow channel divided by the wall forming the third suction port 84c. The third suction pipe 85c is arranged adjacent to the first pipe 85a in the conveying direction. Furthermore, a third suction fan 86c is disposed on the third suction pipe 85c. By driving the third suction fan 86c, air is drawn through the third suction pipe 85c from the plurality of through holes 88.

[0057] By dividing the air into suction pipes 85a, 85b, and 85c that are connected to each suction port 84a, 84b, and 84c, the amount of air drawn from each suction port 84a, 84b, and 84c can be stabilized.

[0058] Furthermore, the first intake fan 86a, the second intake fan 86b, and the third intake fan 86c are controlled independently. In this embodiment, control is implemented such that the intake volume of the first intake fan 86a is greater than that of the second intake fan 86b. Furthermore, control is implemented such that the intake volume of the second intake fan 86b is approximately the same as that of the third intake fan 86c.

[0059] Thus, the sheet W can be peeled off from the first mesh belt 72, and one surface Wa of the sheet W peeled off from the first mesh belt 72 comes into contact with the second mesh belt 81. Moreover, since one surface Wa of the sheet W is in contact with the second mesh belt 81, the sheet W is conveyed in a held state.

[0060] A humidifying unit 90 is disposed below the sheet conveying section 80. The humidifying unit 90 is disposed opposite to the second mesh belt 81. The humidifying unit 90 supplies moisture to the other side Wb of the lower surface of the sheet W, which is in contact with the second mesh belt 81. In the humidifying unit 90, humidifying air (e.g., water vapor or mist) is supplied to the sheet W as moisture.

[0061] like Figure 2As shown, the humidifier 90 includes a container 91 for storing water and a piezoelectric vibrator 92 disposed at the bottom of the container 91. An outlet 93 for discharging humidified air is formed at the upper part of the container 91. The container 91 is configured such that the outlet 93 faces the other side Wb of the sheet material W. By driving the piezoelectric vibrator 92, ultrasonic waves are generated in the water, thereby generating mist (humidified air) inside the container 91. The generated mist is supplied to the sheet material W through the outlet 93 of the container 91. By supplying moisture from below the sheet material W, even if condensation occurs at or near the humidifier 90, water droplets will not fall onto the sheet material W. That is, for example, if moisture is supplied to the sheet material W from above, moisture may adhere to or near the humidifier 90 and fall as water droplets, causing water droplets to adhere to the sheet material W. In this case, the supply of moisture to the sheet material W becomes uneven. However, in this embodiment, the falling of water droplets is suppressed, thereby avoiding any impact on the quality of the sheet S.

[0062] In addition, such as Figure 4 As shown, the outlet 93 of the humidification unit 90 is an elongated rectangle extending along the X-axis when viewed along the -Z direction. A wire mesh 94 is disposed on the outlet 93 to prevent the entry of garbage and the like into the container 91.

[0063] Here, the suction mechanism 83 is positioned opposite the humidification unit 90, separated by the second mesh belt 81. Furthermore, in this embodiment, the first suction port 84a and the discharge port 93 are arranged facing each other. The first suction pipe 85a draws in the humidified air discharged from the humidification unit 90. Thus, the humidified air discharged from the discharge port 93 is drawn in through the first suction port 84a, which faces the discharge port 93, and then through the first suction pipe 85a. By being drawn in by the first suction port 84a, the humidified air passes through the material sheet W in a stable airflow state. This allows for the uniform distribution of moisture in the in-plane direction of the material sheet W.

[0064] Furthermore, the first suction port 84a and the discharge port 93 have the same shape and size. Specifically, the first suction port 84a and the discharge port 93 are rectangular when viewed from above, and their dimensions along the X-axis and along the Y-axis are approximately the same.

[0065] Therefore, for example, when humidified air discharged from outlet 93 is drawn from a suction port that is larger than the size of outlet 93, air from other areas within the suction port, including the periphery of outlet 93, will also be drawn. Consequently, the suction resistance at each suction port will vary, resulting in variations in the airflow of humidified air passing through the sheet W directly above outlet 93. In this embodiment, the first suction port 84a, the second suction port 84b, and the third suction port 84c are connected to the first suction pipe 85a, the second suction pipe 85b, and the third suction pipe 85c, respectively, and each functions independently. Furthermore, by making the shape and size of each opening of the first suction port 84a and outlet 93 identical, the airflow of humidified air passing through the sheet W directly above outlet 93 becomes constant. This allows for uniform moisture content in the in-plane direction of the sheet W, thereby suppressing in-plane strength variations and ensuring sheet quality.

[0066] Furthermore, the second suction pipe 85b and the third suction pipe 85c draw air to make the sheet W adhere tightly to the second mesh belt 81. Therefore, the suction mechanism 83 has the functions of peeling the sheet W off the first mesh belt 72 and adhering it to the second mesh belt 81, and of supplying moisture in the thickness direction of the sheet W. Therefore, the structure of the sheet manufacturing apparatus 1 can be simplified.

[0067] The moisture content of the sheet W after being moistened in the humidification section 90 is preferably 12% by mass or more and 40% by mass or less. By using the specified moisture content of the sheet, hydrogen bonds between fibers can be effectively formed, thereby increasing the strength of the sheet S.

[0068] A sheet forming section 110 is disposed downstream of the sheet conveying section 80 and the humidifying section 90. The sheet W, after being given moisture, is conveyed to the sheet forming section 110.

[0069] Here, an air jetting section 100 is provided at the end of the sheet conveying section 80 located on the side of the sheet forming section 110. The air jetting section 100 jets compressed air at the sheet W.

[0070] like Figure 2 As shown, the air jet unit 100 is positioned adjacent to the exit side roller 82a, which is one of the multiple rollers 82 within the sheet conveying unit 80 located closest to the sheet forming unit 110. More specifically, the air jet unit 100 is positioned between the downstream end of the suction mechanism 83 in the conveying direction and the exit side roller 82a. This allows for efficient and effective stripping of the sheet W from the second mesh belt 81.

[0071] The air jet unit 100 includes a compression unit (not shown) for compressing air and a nozzle 101 for discharging the compressed air. The nozzle 101 is positioned adjacent to the exit side roller 82a and facing the second mesh belt 81. This allows the sheet W peeled off from the second mesh belt 81 to be conveyed to the sheet forming unit 110.

[0072] When viewed along the +Z direction, nozzle 101 has an elongated opening extending along the X-axis. Figure 3 The length of nozzle 101 along the X-axis is approximately the same as the length of sheet W conveyed by sheet conveying section 80 along the X-axis.

[0073] Furthermore, the air injection section 100 injects compressed air onto the surface Wa of the material sheet W that is in contact with the second mesh belt 81. The compressed air is injected from the nozzle 101 onto the entire material sheet W along the X-axis direction.

[0074] Because the sheet W being conveyed by the sheet conveying section 80 is moistened by the humidifying section 90 while in contact with the second mesh belt 81, the adhesive force relative to the second mesh belt 81 is increased, causing the sheet W to adhere to the second mesh belt 81. Furthermore, if the sheet W does not peel off from the second mesh belt 81 by gravity alone, it will not be smoothly conveyed to the sheet forming section 110, resulting in poor conveying of the sheet W or damage to the sheet W.

[0075] According to this embodiment, by spraying compressed air toward the sheet W near the front of the sheet forming section 110 in the conveying direction, the second mesh belt 81 is pressed downwards. As a result, the sheet W is peeled off from the second mesh belt 81, allowing it to be smoothly transferred to the sheet forming section 110. Therefore, poor conveying of the sheet W and damage to the sheet can be suppressed.

[0076] The sheet forming section 110 forms a sheet S by heating and pressurizing at least one of the following processes: heating the sheet W that has been moistened and peeled off from the second mesh belt 81. In this embodiment, the sheet forming section 110 heats the sheet W that has been moistened while pressurizing it. As a result, the moisture contained in the sheet W evaporates after the temperature rises, and the thickness of the sheet W becomes thinner, thereby increasing the fiber density. By using heat to raise the temperature of the moisture and adhesive, and using pressure to increase the fiber density, the adhesive is gelatinized, and then the moisture is evaporated and the gelatinized adhesive is used to bond multiple fibers together. Furthermore, by using heat to evaporate the moisture and using pressure to increase the fiber density, multiple fibers are bonded together by hydrogen bonding. As a result, a sheet S with better mechanical strength can be formed.

[0077] The sheet forming section 110 of this embodiment includes a pressure heating section 114 for pressurizing and heating the sheet W. The pressure heating section 114 can be constructed using, for example, heating rollers or a hot stamping forming machine. In the illustrated example, the pressure heating section 114 is constructed from a pair of heating rollers 116. The sheet W is heated in the pair of heating rollers 116 to a temperature of 60°C or higher and 100°C or lower. Furthermore, pressure is applied to the sheet W by the heating rollers 116 to thin the sheet W, thereby increasing the fiber density in the sheet W. The pressure applied to the sheet W is preferably 0.1 MPa or higher and 15 MPa or lower, more preferably 0.2 MPa or higher and 10 MPa or lower, and even more preferably 0.4 MPa or higher and 8 MPa or lower. Within this pressure range, fiber deterioration can be suppressed, and the defiber obtained by defibering the manufactured sheet S can be used as raw material to remanufacture a sheet S with good strength.

[0078] Furthermore, the number of heating roller pairs 116 is not particularly limited. The heating roller pairs 116 allow for simultaneous pressure and heating of the sheet W. This also simplifies the structure of the sheet manufacturing apparatus 1.

[0079] In addition, the sheet forming section 110 may also be a structure that includes a pressure roller and a conveyor belt (e.g., a mesh belt).

[0080] like Figure 1 As shown, the cutting section 120 cuts the sheet S formed by the sheet forming section 110. In the illustrated example, the cutting section 120 has a first cutting section 122 and a second cutting section 124, wherein the first cutting section 122 cuts the sheet S in a direction intersecting the conveying direction of the sheet S, and the second cutting section 124 cuts the sheet S in a direction parallel to the conveying direction. The second cutting section 124 cuts the sheet S after it has passed through the first cutting section 122.

[0081] Through the above method, a single sheet S of a predetermined size is formed. The cut single sheet S is discharged to the discharge receiving part 130. In addition, the sheet S manufactured by the sheet manufacturing apparatus of the present invention includes not only thinner sheets with a thickness of about 0.1 mm used in printing and the like, but also sheet-shaped molded articles with a thickness of about 10 to 30 mm that can be used in a variety of applications such as cushioning materials and heat insulation materials.

[0082] Next, the functions of the sheet conveying unit 80 and the air jetting unit 100 will be explained.

[0083] like Figure 5AAs shown, the sheet W, which is stacked on the first mesh belt 72 by the stacking section 60, is conveyed along the conveying direction. Furthermore, the suction mechanism 83 of the sheet conveying section 80 generates an upward airflow on the second mesh belt 81 to suction the sheet W. Specifically, firstly, by suction from the second suction port 84b, the sheet W is peeled off the first mesh belt 72, and is conveyed with one surface Wa of the sheet W in contact with the second mesh belt 81.

[0084] Next, as Figure 5B As shown, moisture (humidified air) is supplied from the humidification unit 90 to the sheet W being conveyed through the sheet conveying unit 80. That is, in this embodiment, moisture is supplied to the sheet W during the conveying of the sheet W.

[0085] Humidified air discharged from the outlet 93 of the humidification unit 90 is drawn in through the first suction port 84a positioned above the outlet 93. Since the humidified air is drawn in through the first suction port 84a via the sheet W, moisture can be uniformly supplied in the thickness direction of the sheet W.

[0086] In addition, the sheet W is also drawn in by the suction from the first suction port 84a, and is conveyed with one side Wa of the sheet W in contact with the second mesh belt 81.

[0087] Next, as Figure 5C As shown, the sheet W, which has been given moisture, is conveyed by suction from the third suction port 84c, with one side Wa of the sheet W in contact with the second mesh belt 81. Subsequently, the sheet W is conveyed in a state of being tightly adhered to the second mesh belt 81 due to the increased adhesion caused by the application of moisture.

[0088] Next, at a precise timing when the top of the sheet W passes opposite the exit side roller 82a, the air injection unit 100 injects compressed air from the nozzle 101 toward one surface Wa of the sheet W. The timing of the compressed air injection is controlled, for example, by a second conveyor belt drive time or a detection sensor.

[0089] As a result, the top of the sheet W is peeled off from the second mesh belt 81 and hangs downwards. Moreover, the top of the sheet W peeled off from the second mesh belt 81 is held by the heating roller pair 116 of the sheet forming section 110. After the top of the sheet W is held by the heating roller pair 116, the injection of compressed air is stopped.

[0090] Furthermore, the timing of compressed air injection from the air injection unit 100 can be appropriately set according to the manufacturing conditions of the sheet S. For example, it can be injected for a few seconds from slightly in front of the exit side roller 82a from the top of the sheet W. In addition, the pressure of the compressed air injected from the air injection unit 100 and the injection time can be appropriately set.

[0091] According to this embodiment, the humidified air discharged from the outlet 93 of the humidification unit 90 is drawn in by the suction force from the first suction port 84a disposed facing the ground with respect to the outlet 93. As a result, since the humidified air is drawn in through the first suction port 84a via the sheet W, the moisture content in the in-plane direction of the sheet W becomes uniform, thereby suppressing unevenness in the strength of the sheet S in the in-plane direction and ensuring the quality of the sheet S.

[0092] Furthermore, by setting the shape and size of each opening of the first suction port 84a and the discharge port 93 to be the same, the airflow of humidified air passing directly above the material sheet W of the discharge port 93 becomes constant. This enables the uniformity of moisture content in the in-plane direction of the material sheet W.

[0093] Alternatively, in the sheet manufacturing apparatus 1 of the present invention, it may be configured such that the fibers discharged from the screening section 40 are directly supplied to the mixing section 50. In this case, the first sheet forming section 45 and the rotating body 49 are unnecessary. Moreover, the sheet V is not formed from the fibers discharged from the screening section 40, but is instead supplied directly to the mixing section 50.

[0094] Symbol Explanation

[0095] 1…Sheet manufacturing apparatus; 10…Feeding section; 11…Crushing section; 12…Crushing blade; 14…Hopper; 15, 16, 17, 18…Pipes; 19…Hopper; 20…Defiber unwinding section; 22…Inlet; 24…Outlet; 40…Screwing section; 41…Roller section; 42…Inlet; 43…Shell section; 44…Outlet; 45…First sheet forming section; 46…Wire mesh belt; 47…Setting roller; 47a…Frame 48…Suction mechanism; 49…Rotating body; 49a…Base; 49b…Protrusion; 50…Mixing section; 52…Adhesive supply section; 54…Pipe; 56…Blower; 60…Accumulation section; 61…Roller section; 62…Inlet; 63…Shell section; 70…Second sheet forming section; 72…First mesh belt; 74…Setting roller; 76…Suction mechanism; 80…Sheet conveying section; 81…Second mesh belt; 82… …roller; 82a…exit side roller; 83…suction mechanism; 84…suction port; 84a…first suction port; 84b…second suction port; 84c…third suction port; 85a…first suction pipe; 85b…second suction pipe; 85c…third suction pipe; 86…suction fan; 86a…first suction fan; 86b…second suction fan; 86c…third suction fan; 88…through hole; 90… Humidification section; 91… Container; 92… Piezoelectric vibrator; 93… Discharge port; 94… Wire mesh; 100… Air jet section; 101… Nozzle; 110… Sheet forming section; 114… Pressurized heating section; 116… Heating roller pair; 120… Cutting section; 122… First cutting section; 124… Second cutting section; 130… Discharge receiving section; W… Sheet; Wa… One side; Wb… The other side; S… Sheet.

Claims

1. A sheet manufacturing apparatus characterized by comprising: A sheet is manufactured from a material containing fibers, The sheet manufacturing apparatus includes: a piling section that causes the material containing the fibers to pile up by an air current to form a web; a web conveying section that includes a conveying belt that contacts one face that is an upper face of the web and holds the web; a humidifying section that is disposed so as to face the one face side of the conveying belt across the web and gives moisture from the other face side that is a lower face of the web to the upper side; a suction section that is disposed so as to face the humidifying section across the conveying belt, the suction section has a plurality of suction ports for sucking air, the humidifying section has a discharge port that discharges humidified air, the first suction port of the plurality of suction ports and the discharge port are arranged so as to face each other.

2. The sheet manufacturing apparatus according to claim 1, wherein the opening shape and size of the first suction port and the discharge port are the same.

3. The sheet manufacturing apparatus according to claim 1, wherein the plurality of suction ports further include a second suction port that is disposed so as to be adjacent to the first suction port in a conveying direction of the conveying belt.

4. The sheet manufacturing apparatus according to claim 3, wherein the suction section has a first suction duct that is connected to the first suction port and a second suction duct that is connected to the second suction port.

5. The sheet manufacturing apparatus according to claim 4, wherein the second suction duct is disposed so as to be adjacent to the first suction duct in the conveying direction.

6. The sheet manufacturing apparatus according to claim 4, wherein the first suction duct sucks the humidified air discharged from the humidifying section.

7. The sheet manufacturing apparatus according to claim 4, wherein the second suction duct causes the web to adhere to the conveying belt by suction.

8. The sheet manufacturing apparatus according to claim 4, wherein the first suction duct has a first suction fan, the second suction duct has a second suction fan, the first and second suction fans are independently controlled.

9. The sheet manufacturing apparatus according to claim 3, wherein the suction section has a third suction port that is disposed at a position adjacent to the first suction port, the first suction port being located between the second suction port and the third suction port.

10. The sheet manufacturing apparatus according to claim 9, wherein a third suction duct that is connected to the third suction port is provided.

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