JP2023165126A - Sheet production apparatus - Google Patents

Abstract

To provide a sheet production apparatus capable of reducing variations in web thickness.SOLUTION: A sheet production apparatus 1 includes: a dispersion part 101 for dispersing fibers: and a deposition part 102 for depositing the dispersed fibers to form a web W. The dispersion part 101 includes a blade part 83 which includes multiple opening parts 84 arranged so as to correspond to the width direction of the web. The blade part 83 includes shutter parts 85 each corresponding to one of the multiple opening parts 84. The shutter parts 85 each open and close the corresponding one of the opening parts 84 individually.SELECTED DRAWING: Figure 4

Description

The present invention relates to a sheet manufacturing apparatus.

BACKGROUND ART Conventionally, sheet manufacturing apparatuses have been known that manufacture sheets from webs on which fibers are deposited. For example, Patent Document 1 discloses a fibrous body deposition device in which materials such as fibers are loosened by rotation of a rotating body and then deposited.

JP2020-84394A

However, the apparatus described in Patent Document 1 has a problem in that it is difficult to reduce variations in web thickness. Specifically, if the direction along the rotation axis of the rotating body of the dispersion section is defined as the width direction of the rotating body, the material is supplied from above the center in the width direction of the rotating body. Therefore, especially when forming a wide web in the width direction, variations in thickness tend to occur in the width direction. When the variation in the thickness of the web becomes significant, the produced sheets may also have non-uniform thickness, making it difficult to improve the quality. That is, there has been a need for a sheet manufacturing apparatus that reduces variations in web thickness.

The sheet manufacturing device includes a dispersion section that disperses fibers, and a deposition section that deposits the dispersed fibers to form a web, and the dispersion section is arranged corresponding to the width direction of the web. The blade includes a blade portion having a plurality of openings, the blade portion includes a shutter portion corresponding to each of the plurality of openings, and each of the shutter portions individually opens and closes the corresponding opening. It is characterized by

FIG. 1 is a schematic diagram showing the configuration of a sheet manufacturing apparatus according to an embodiment. FIG. 3 is a perspective view showing the configuration of a forming section and the like. FIG. 3 is a cross-sectional view showing the action of the forming part. FIG. 3 is a perspective view showing the configuration of a rotating member. FIG. 3 is a schematic diagram showing a fully open state of the opening in the shutter section. FIG. 3 is a schematic diagram showing a fully closed state of an opening in the shutter section. FIG. 3 is a block diagram showing the configuration of a control section. FIG. 3 is a flow diagram showing a method of controlling opening and closing of an opening by a shutter section. FIG. 3 is a flow diagram showing a method of controlling opening and closing of an opening by a shutter section. 2 is a graph showing variations in web thickness according to Examples and Comparative Examples.

In the embodiment described below, a sheet manufacturing apparatus for manufacturing a sheet from a web formed by dry processing will be exemplified and explained with reference to the drawings. In each of the following figures, XYZ axes that are mutually orthogonal coordinate axes are attached as necessary, the direction pointed by the arrow is defined as a + direction, and the direction opposite to the + direction is defined as a - direction. -Z direction coincides with the vertical direction. The +Z direction is sometimes referred to as upward, and the -Z direction is sometimes referred to as downward.

In sheet manufacturing equipment, webs, etc., the direction along the Y axis is the width direction, and the direction along the Z axis is the thickness direction. Furthermore, in a sheet manufacturing apparatus, the end of the raw material, web, etc. in the conveyance direction is sometimes referred to as downstream, and the side that goes back in the conveyance direction is sometimes referred to as upstream. In addition, for convenience of illustration, the size of each member is made different from the actual size.

1. Sheet Manufacturing Apparatus As shown in FIG. 1, the sheet manufacturing apparatus 1 according to the present embodiment includes, from upstream to downstream, a supply section 5, a coarse crushing section 10, a defibrating section 30, a mixing section 60, and a forming section 100. , a web conveying section 70, a forming section 150, and a cutting section 160. Further, the sheet manufacturing apparatus 1 includes a control section 28 that integrally controls the operation of each of the above components. The sheet manufacturing apparatus 1 manufactures a sheet S, which is a sheet-shaped molded body.

The supply section 5 supplies the raw material C to the coarse crushing section 10 . The supply section 5 is equipped with an automatic feed mechanism, and continuously and automatically feeds the raw material C into the coarse crushing section 10. Raw material C is a material containing fibers. Examples of materials containing fibers include paper, cardboard, pulp, pulp sheets, sawdust, wood shavings, wood, and fabric.

By defibrating such a raw material C in a defibrating section 30 described later, cellulose fibers are obtained as a defibrated product. Cellulose fiber is a fiber contained in plant fibers such as wood, and is a carbohydrate. Cellulose fiber is one of the main components of the sheet S manufactured by the sheet manufacturing apparatus 1. The fibers applied to the sheet S may include synthetic fibers such as polypropylene, polyester, and polyurethane in addition to cellulose fibers. From the viewpoint of reducing environmental load, it is preferable to use fibers derived from natural products such as cellulose fibers.

The crushing section 10 shreds the raw material C supplied from the supply section 5 in air such as the atmosphere. The coarse crushing section 10 has a coarse crushing blade 11. The coarse crushing section 10 is, for example, a shredder or a cutter mill. The raw material C is shredded into small pieces by the crushing blade 11. The planar shape of the strip is, for example, several mm square or irregular. The strips are collected in a metering section 50.

The quantitative supply section 50 measures and supplies the strips to the hopper 12 in a quantitative manner. The quantitative supply unit 50 is, for example, a vibration feeder. The fine pieces supplied to the hopper 12 are conveyed to the inlet 31 of the defibrating section 30 via the pipe 20.

The defibrating section 30 includes an inlet 31, an outlet 32, a stator 33, a rotor 34, and an airflow generation mechanism (not shown). The defibrating section 30 defibrates the pieces of the raw material C in a dry manner to generate fibers. The pieces of raw material C are introduced into the defibration section 30 through the introduction port 31 by the airflow of the airflow generation mechanism. Note that in this specification, dry method means that the method is not performed in a liquid, but is performed in air such as the atmosphere.

The stator 33 and the rotor 34 are arranged inside the defibrating section 30. The stator 33 has a substantially cylindrical inner surface. The rotor 34 rotates along the inner surface of the stator 33. The pieces of raw material C are sandwiched between the stator 33 and the rotor 34, and are defibrated by the shear force generated between them.

The fibers produced by fibrillation preferably have a fiber length of 1.0 mm or more. According to this, the mechanical strength of the sheet S is improved because the fibers are not excessively shortened. The fiber length is determined by a method based on ISO 16065-2:2007.

The fibers are discharged from the outlet 32 of the defibrating section 30 into the tube 40 . The pipe 40 communicates with the inside of the defibrating section 30 and the inside of the forming section 100 . The fibers are conveyed from the defibrating section 30 to the forming section 100 via the pipe 40 by the airflow generated by the airflow generation mechanism. A mixing section 60 is provided in the tube 40 .

Mixing section 60 includes hoppers 13 and 14, supply pipes 61 and 62, and valves 65 and 66. The mixing unit 60 mixes a binder and an additive into the fibers conveyed through the air in the tube 40 . This produces a mixture.

Hopper 13 feeds binding material into tube 40 . Hopper 13 communicates with the inside of tube 40 via supply tube 61. In the supply pipe 61, a valve 65 is arranged between the hopper 13 and the pipe 40. Valve 65 regulates the weight of binder supplied from hopper 13 to tube 40 . A valve 65 adjusts the mixing ratio of fibers and binder. The binding material may be supplied as a powder or may be supplied in a molten state.

The binder binds the fibers together. A thermoplastic or thermosetting resin is used as the bonding material. Examples of resins include shellac, pine resin, dammar, polylactic acid, plant-derived polybutylene succinate, plant-derived polyethylene, and Kaneka's PHBH (registered trademark) (Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate)). Examples include resins derived from natural products such as, and known synthetic resins. As the binding material, one of these types may be used alone or two or more types may be used in combination. From the viewpoint of reducing environmental load, the binding material is preferably a resin derived from a natural product.

Hopper 14 supplies additive into tube 40 . Hopper 14 communicates with the interior of tube 40 via supply tube 62 . In the supply pipe 62, a valve 66 is located between the hopper 14 and the pipe 40. Valve 66 regulates the weight of additive fed into tube 40 from hopper 14 . A valve 66 adjusts the mixing ratio of additives to fibers and binder.

Examples of additives include colorants, flame retardants, antioxidants, ultraviolet absorbers, aggregation inhibitors, antibacterial agents, fungicides, waxes, and mold release agents. Note that the additive is not an essential component in the sheet S, and the hopper 14, supply pipe 62, etc. may be omitted. Alternatively, the additive may be mixed with the binder in advance and supplied from the hopper 13.

The fibers, binder, and the like are mixed while being conveyed through the tube 40 to the forming section 100 to form a mixture. In order to promote mixture production in the tube 40 and improve transportability of the mixture, a blower or the like that generates an air current may be disposed in the tube 40. The mixture is introduced into the forming section 100 via a supply member 42 that connects the downstream end of the tube 40 and the forming section 100 .

The forming unit 100 generates the web W by depositing a mixture containing fibers, a binder, and the like in the air. The forming section 100 has a dispersion section 101 and a deposition section 102. The dispersion section 101 is arranged inside the deposition section 102 . The interior of the dispersion section 101 communicates with the pipe 40 via the supply member 42 . A web conveyance section 70 is arranged below the deposition section 102 .

The dispersion section 101 includes a rotating member 101a and a drum section 101b that accommodates the rotating member 101a. The forming section 100 takes the mixture from the supply member 42 into the dispersion section 101 and deposits it on the mesh belt 122 of the web conveyance section 70 in a dry manner.

As shown in FIGS. 2 and 3, the inside of the supply member 42 communicates with the inside of the drum section 101b. The drum portion 101b is a substantially columnar member, and the height direction of the substantially columnar shape is along the Y axis. The lower part of the drum part 101b is formed of metal mesh. The mesh of the metal mesh allows fibers, binders, etc. contained in the mixture to pass through. In addition, in FIGS. 2 and 3, in addition to the forming section 100, the pipe 40, the supply member 42, and the web conveyance section 70 are also shown.

The rotating member 101a is a +-shaped member when viewed from the side in the -Y direction. The rotating member 101a includes a plurality of blades each having a plurality of openings, which will be described later. Although not shown in the drawings, the rotating member 101a is supported by a support section and rotates about a rotation axis O along the Y-axis by driving of a drive section.

The deposition section 102 is a substantially box-shaped member. In the deposition section 102, the supply member 42 is arranged above the top surface, and the dispersion section 101 is arranged inside the top surface. A region corresponding to the bottom surface of the deposition section 102 is open downward. The dispersion section 101 is located within the deposition section 102 and faces the upper surface of the mesh belt 122 of the web conveyance section 70 . The deposition section 102 is made of, for example, resin or metal.

A mixture (not shown) is introduced from the pipe 40 into the supply member 42 as a flow F, and reaches the inside of the dispersion section 101 as a downward flow F within the supply member 42 . The mixture is loosened by passing through an opening of the rotating member 101a, which will be described later, or between the rotating member 101a and the drum portion 101b. The plurality of fibers in the mixture are untangled and separated into individual fibers, which then pass through the mesh of the drum portion 101b. Thereby, the dispersion section 101 disperses the fibers, binder, etc. contained in the mixture into the air inside the deposition section 102.

The mixture is discharged from inside the dispersion section 101 into the air in the deposition section 102 and guided above the mesh belt 122 by gravity and the suction force of the suction mechanism 110, which will be described later. Therefore, the mixture is deposited on the upper surface of the mesh belt 122 via the first base material N1, which will be described later. That is, the deposition unit 102 forms the web W by depositing a mixture containing dispersed fibers.

Returning to FIG. 1, the web conveyance unit 70 includes a mesh belt 122 and a suction mechanism 110. The mesh belt 122 is an endless belt, and is stretched by four tension rollers 121.

The mesh belt 122 has enough strength to hold the web W and the like without interfering with suction by the suction mechanism 110, which will be described later. The mesh belt 122 is made of metal or resin, for example. The mesh hole diameter of the mesh belt 122 is not particularly limited, but is preferably 60 μm or more and 125 μm or less.

At least one of the four tension rollers 121 is rotationally driven by a motor (not shown). The upper surface of the mesh belt 122 moves downstream as the tension roller 121 rotates. In other words, the mesh belt 122 rotates clockwise in FIG. 1 . As the mesh belt 122 rotates, a first base material N1 and a web W, which will be described later, are conveyed downstream.

A base material supply section 71 is arranged in the -X direction of the web conveyance section 70. The base material supply unit 71 rotatably supports a roll-shaped first base material N1. The first base material N1 is continuously supplied from the base material supply section 71 to the upper surface of the mesh belt 122.

The web W is sandwiched between the first base material N1 and a second base material N2, which will be described later. For example, a woven fabric or a nonwoven fabric is applied to the first base material N1 and the second base material N2. It is preferable that the first base material N1 has a structure that does not hinder the suction of the suction mechanism 110. For example, a polyester long fiber nonwoven fabric manufactured by a spunbond method is applied to the first base material N1 and the second base material N2.

Since the sheet S is formed by laminating the first base material N1, the web W, and the second base material N2, the mechanical strength is improved. Note that in the sheet S, the first base material N1 and the second base material N2 are not essential components, and either one or both may be omitted.

When the base material supply unit 71 supplies the first base material N1 to the mesh belt 122, the first base material N1 is conveyed on the mesh belt 122 in the +X direction. While the first base material N1 is being conveyed, the mixture descends from the deposition section 102 and is deposited on the upper surface. Thereby, the web W is continuously formed on the upper surface of the first base material N1. The mesh belt 122 conveys the web W together with the first base material N1 downstream.

The suction mechanism 110 is arranged below the dispersion section 101. Suction mechanism 110 facilitates deposition of the mixture onto mesh belt 122. The suction mechanism 110 sucks air in the deposition section 102 through the mesh belt 122 and the plurality of holes in the first base material N1. The plurality of holes in the mesh belt 122 and the first base material N1 allow air to pass through, but it is difficult for fibers, binding materials, etc. contained in the mixture to pass therethrough. The mixture discharged from the dispersion section 101 into the deposition section 102 is sucked downward together with air. The suction mechanism 110 employs a known suction device such as a blower.

Thereby, the mixture in the deposition section 102 is deposited on the upper surface of the first base material N1 by the suction force of the suction mechanism 110 in addition to gravity, and becomes the web W. The web W contains a relatively large amount of air and is soft and swollen. The web W is conveyed downstream together with the first base material N1 by the mesh belt 122.

A sensor section 285 is provided in the +X direction of the depositing section 102 at a position facing the web W above the mesh belt 122. The sensor section 285 is included in the control section 28.

The sensor section 285 detects the deposition state of the mixture containing fibers in the deposition section 102. Specifically, the sensor unit 285 measures the thickness of the web W in a non-contact manner. Although not shown, a plurality of sensor units 285 are arranged along the Y axis. The sensor unit 285 measures the thickness of the web W at a plurality of locations in the width direction of the web W, that is, in the direction along the Y axis. The sensor section 285 measures the thickness of the web W at a plurality of locations while being conveyed downstream.

Here, the mixture forming the web W is dispersed in a relatively long dispersion section 101 in the direction along the Y axis. Therefore, in the web W formed using the conventional technique, variations in thickness tend to occur in the direction along the Y axis.

On the other hand, the sheet manufacturing apparatus 1 includes a rotating member 101a including a blade portion and a plurality of openings, which will be described later. Therefore, variations in the thickness of the web W in the direction along the Y axis can be reduced. In addition, in the sheet manufacturing apparatus 1, the control unit 28 calculates the thickness of the web W measured by the plurality of sensor units 285, and each opening is individually controlled to open and close. As a result, the above-mentioned variation in thickness is further reduced. Details of the configuration of the blade portion and the opening/closing control of the opening will be described later.

A known sensor can be applied to the sensor section 285. The sensor unit 285 is, for example, an optical distance sensor. The thickness of the web W is measured by the sensor section 285, and the web W is conveyed further downstream.

A humidifier may be disposed downstream of the sensor section 285 to spray water onto the web W on the mesh belt 122 to humidify it. This suppresses scattering of fibers, binding materials, etc. contained in the web W. Alternatively, a water-soluble additive or the like may be included in the water used for humidification, and the web W may be impregnated with the additive in parallel with humidification.

A dancer roller 141 is arranged downstream of the web conveyance section 70. After the web W is peeled off from the tension roller 121 on the most downstream side, it is drawn into the dancer roller 141. The dancer roller 141 secures machining time downstream. Specifically, the molding in the molding section 150 is a batch process. Therefore, the dancer roller 141 is moved up and down to delay the time for the web W continuously conveyed from the deposition section 102 to reach the forming section 150.

A base material supply section 72 is arranged downstream of the dancer roller 141 and upstream of the forming section 150. The base material supply unit 72 rotatably supports a roll-shaped second base material N2. The second base material N2 is continuously supplied to the upper surface of the web W from the base material supply section 72. Thereby, the web W is sent out to the forming section 150 while being sandwiched between the lower first base material N1 and the upper second base material N2.

The molding section 150 is a hot press device and includes an upper substrate 152 and a lower substrate 151. The molding unit 150 molds the first base material N1, the web W, and the second base material N2 into a continuous form sheet S. The upper substrate 152 and the lower substrate 151 are pressurized with the web W sandwiched therebetween, and are heated by a built-in heater.

The web W is compressed from above and below by pressure to increase its density, and the binding material is melted by heating and spreads between the fibers. When heating is completed in this state and the binding material is solidified, the fibers are bonded to each other by the binding material. As a result, a continuous document-like sheet S consisting of three layers of the first base material N1, the web W, and the second base material N2 is formed. The continuous form sheet S advances to the downstream cutting section 160.

In addition, in the molding section 150, molding may be continuously performed using a heating roller and a pressure roller instead of the heating press device. In this case, the dancer roller 141 may be omitted.

The cutting unit 160 cuts the sheet S from a continuous form into a single form. Although not shown, the cutting section 160 includes a vertical blade and a horizontal blade. The vertical blade and the horizontal blade are, for example, a rotary cutter. Further, an ultrasonic cutter or the like may be used instead of the rotary cutter.

The vertical blade cuts the continuous form sheet S in a direction parallel to the traveling direction. The horizontal blade cuts the continuous form sheet S in a direction intersecting the traveling direction. Thereby, the sheet S is processed into a substantially rectangular cut shape and stored in the tray 170.

Examples of uses of the sheet S include cushioning materials, heat insulating materials, sound absorbing materials, and liquid absorbing materials. The sheet S is not limited to a relatively thin sheet shape, but may be a plate shape or a relatively thick block shape. Furthermore, irregularities may be formed on the sheet S by secondary processing.

2. Rotating Member As shown in FIG. 4, the rotating member 101a includes a rotating shaft portion 81 and a plurality of blade portions 83a, 83b, 83c, and 83d. The rotating shaft portion 81 is a columnar member, and the height direction of the column is arranged along the Y-axis. The central axis of the rotating shaft portion 81 coincides with the rotating axis O of the rotating member 101a. A plurality of blade portions 83a, 83b, 83c, and 83d are attached to the rotating shaft portion 81 radially from the rotating shaft portion 81 when viewed from the side in the −Y direction.

In the following description, the blade portions 83a, 83b, 83c, and 83d may be collectively referred to simply as the blade portion 83. Although the rotating member 101a of this embodiment has four blade parts 83a, 83b, 83c, and 83d, it is not limited thereto.

The blade portion 83 is a substantially rectangular plate-like member, and each long side is arranged along the rotation shaft portion 81. The blade portion 83 has an end in the +Y direction and an end in the −Y direction attached to the rotating shaft portion 81 via a +-shaped member (not shown). There is a gap between each long side of each blade portion 83 on the rotating shaft portion 81 side and the rotating shaft portion 81 . The blade portion 83 is made of, for example, resin or metal.

Here, the blade portions 83a, 83b, 83c, and 83d are rotationally symmetrical with respect to the rotation axis O. Therefore, in the following explanation, only the blade portion 83a will be described, and descriptions of the other blade portions 83b, 83c, and 83c will be omitted.

The blade portion 83a includes a plurality of openings 84, a plurality of shutter portions 85a, 85b, 85c, and 85d, and a plurality of shutter drive portions 87. Specifically, eight openings 84 are arranged corresponding to the direction along the Y-axis, which is the width direction of the web W. The eight openings 84 are arranged at approximately equal intervals from the end in the −Y direction toward the end in the +Y direction in the blade portion 83a. Each opening 84 is approximately rectangular. The long side of each opening 84 extends in a radial direction centered on the rotation axis O.

In the following description, the shutter sections 85a, 85b, 85c, and 85d are also collectively referred to as the shutter section 85, or any one of them may be referred to simply as the shutter section 85. Furthermore, each of the shutter sections 85 and the opening section 84 and shutter drive section 87 corresponding to each shutter section 85 have the same configuration.

The shutter sections 85 are arranged in the order of shutter section 85a, shutter section 85b, shutter section 85c, and shutter section 85d from the -Y direction to the +Y direction. Each of the shutter portions 85 corresponds to one of the plurality of openings 84. One shutter section 85 is provided corresponding to the two openings 84. Each of the four shutter sections 85 opens and closes the corresponding opening 84 individually. That is, one shutter section 85 opens and closes two corresponding openings 84. Note that FIG. 4 shows a state in which all the openings 84 are open.

The shutter portion 85 is a substantially rectangular plate member. The shutter portion 85 is provided with one slit portion 86 approximately at the center in the direction along the Y-axis. One slit portion 86 has approximately the same shape as one opening portion 84 when viewed in plan from the normal direction of the blade portion 83a.

Each shutter section 85 is attached with a shutter drive section 87 and a pair of guide sections 88. The pair of guide portions 88 are each substantially prismatic members. The pair of guide parts 88 are arranged along the long sides of the blade part 83a, and support the shutter part 85 with the shutter part 85 sandwiched between them. The shutter section 85 is supported by a pair of guide sections 88 and can reciprocate in the direction along the Y-axis.

The shutter drive section 87 is arranged near the guide section 88 on the rotating shaft section 81 side with respect to the shutter section 85 . The shutter drive unit 87 is a drive mechanism that includes an actuator and a spring member. For example, the shutter drive section 87 operates an actuator to move the shutter section 85 in the -Y direction. Further, when the shutter driving section 87 stops the actuator, the shutter section 85 moves in the +Y direction by the action of the spring member. Known technology such as a piezoelectric element is applied to the actuator.

As shown in FIG. 5, when the shutter section 85 is moved the most in the +Y direction, one opening section 84 and the slit section 86 overlap. As a result, the two openings 84 corresponding to one shutter section 85 are both fully open.

As shown in FIG. 6, when the shutter section 85 is moved the most in the -Y direction, the two openings 84 and the area of the shutter section 85 other than the slit section 86 overlap. As a result, the two openings 84 corresponding to one shutter section 85 are both fully closed.

The shutter portion 85 is capable of adjusting not only the fully open state and the fully closed state but also the opening ratio of the opening portion 84 . That is, each of the shutter sections 85. The opening/closing state including the degree of opening/closing of the two corresponding openings 84 is changed. This makes it possible to correct variations in the thickness of the web W in the direction along the Y-axis. Therefore, compared to the case where only the opening and closing of each opening 84 is switched, it is possible to further suppress the unevenness of the dispersed fibers.

The plurality of blade parts 83a, 83b, 83c, and 83d rotate around the rotating shaft part 81 as the rotating member 101a rotates, and disperse the mixture containing fibers, binder, and the like. Specifically, the mixture passes through the open opening 84 and between the drum section 101b and the blade sections 83a, 83b, 83c, 83d, etc., thereby becoming loosened and easily dispersed. Since the plurality of blades 83a, 83b, 83c, and 83d are provided, a mixture of fibers and the like can be loosened and dispersed more efficiently than when only one blade is provided.

Opening and closing of the opening 84 by the shutter section 85 is performed under control of the control section 28, which will be described later. Note that the opening portion 84 and the shutter portion 85 are not limited to the number and form described above.

3. Control Unit As shown in FIG. 7, the control unit 28 includes a system bus 280, an input unit 281, a display unit 282, a calculation unit 283, a storage unit 284, a sensor unit 285, and an opening/closing drive unit 286. These components are electrically connected to each other via system bus 280. The control unit 28 is provided, for example, on the main board of the sheet manufacturing apparatus 1.

The sensor section 285 includes a plurality of sensor sections 285a, 285b, 285c, and 285d. The sensor section 285 detects the accumulation state of the fibers of the web W in the above-mentioned accumulation section 102. Specifically, the four sensor sections 285a, 285b, 285c, and 285d of the sensor section 285 are arranged in this order along the Y axis from the -Y direction to the +Y direction. Each of the four sensor sections 285a, 285b, 285c, and 285d measures the thickness of a corresponding region of the web W. By comparing the thicknesses measured by the sensor sections 285a, 285b, 285c, and 285d, variations in the thickness of the web W in the width direction become clear.

The measurement of the thickness of the web W by the sensor unit 285 may be performed continuously, intermittently, or at any timing with respect to the formed web W. Note that the number of sensor units 285 is not limited to four.

The opening/closing drive section 286 includes a plurality of opening/closing drive sections 286a, 286b, 286c, and 286d. The four opening/closing driving parts 286a, 286b, 286c, and 286d of the opening/closing driving part 286 are electrically connected to each shutter driving part 87 (not shown) of the shutter parts 85a, 85b, 85c, and 85d, respectively. Thereby, each of the opening/closing driving sections 286 changes the opening/closing state of each opening 84 by the corresponding shutter section 85.

The arrangement of the four sensor sections 285 and the arrangement of the four shutter sections 85 substantially correspond to each other in the direction along the Y-axis. Specifically, the sensor section 285a and the shutter section 85a correspond, the sensor section 285b and the shutter section 85b correspond, the sensor section 285c and the shutter section 85c correspond, and the sensor section 285d and the shutter section 85d correspond. .

Thereby, when a large variation occurs in the measured thickness of the web W in the width direction, the opening/closing state of the opening 84 can be adjusted by the corresponding shutter section 85 to reduce the variation. Note that the number of sensor sections 285 and the number of opening/closing drive sections 286 and shutter sections 85 are not limited to being the same.

The input unit 281 accepts user settings including settings for opening and closing the opening 84 by the shutter unit 85. The operator of the sheet manufacturing apparatus 1 can arbitrarily change the degree of opening and closing of each opening 84 via the input section 281.

The storage unit 284 includes a ROM (Read Only Memory) and a RAM (Random Access Memory), which are not shown. The ROM stores various control programs executed by the calculation unit 283. Data is temporarily stored in the RAM. The storage unit 284 stores data including user settings regarding the shutter unit 85, the deposition status detected by the four sensor units 285, and the opening/closing status described above.

The calculation unit 283 is a CPU (Central Processing Unit) and controls the entire sheet manufacturing apparatus 1 . In particular, the calculation unit 283 calculates the above data stored in the storage unit 284 and issues an instruction to the four opening/closing drive units 286 to change the opening/closing state of the opening 84.

The display unit 282 displays the above data and notifies the operator. The display section 282 is, for example, a liquid crystal display device, and may be a touch panel type display device integrated with the input section 281.

There are two methods for controlling the shutter section 85 by the control section 28. In the first method, as shown in FIG. 8, the operator determines whether the conditions for opening and closing the shutter section 85 are appropriate. The first method includes steps S1 to S7.

In step S1, the thickness of the web W is measured by the four sensor units 285. The measurement results are transmitted from the sensor section 285 to the calculation section 283.

In step S2, the calculation unit 283 calculates data including the measurement results and the open/closed state of each opening 84 at this time. Thereby, opening and closing conditions for reducing variations in the thickness of the web W are analyzed and calculated. The derived recommended opening/closing conditions are transmitted from the calculation section 283 to the display section 282.

Here, the data calculation in the calculation unit 283 is performed only in the first case with reference to the data table stored in the ROM before the sheet manufacturing apparatus 1 is shipped. The second and subsequent data calculations are performed with reference to both the data table and the data stored in the RAM after the first time.

In step S3, recommended opening/closing conditions are presented to the operator on the display section 282.

In step S4, the operator determines whether the recommended opening/closing conditions are appropriate. If the operator determines that the recommended opening/closing conditions are acceptable and adopts them, the process proceeds to step S6. If the operator determines that the recommended opening/closing conditions are incorrect and corrects them, the process proceeds to step S5.

In step S5, the operator inputs the revised opening/closing conditions from the input section 281. The revised opening/closing conditions are transmitted from the input section 281 to the storage section 284.

In step S6, the opening/closing conditions that the operator has determined to be acceptable or the opening/closing conditions that have been modified by the operator are stored in the RAM of the storage unit 284.

In step S7, the four opening/closing drive units 286 drive the corresponding shutter units 85 to change the opening/closing state including the degree of opening/closing of the opening 84, reflecting the opening/closing conditions.

The second method of controlling the shutter section 85 by the control section 28 is an automatic mode in which the operator does not judge whether the opening/closing conditions of the shutter section 85 are appropriate, as shown in FIG. The second method includes steps S11 to S14.

In step S11, the thickness of the web W is measured by the four sensor units 285. The measurement results are transmitted from the sensor section 285 to the calculation section 283.

In step S12, the calculation unit 283 calculates data including the measurement results and the open/closed state of each opening 84 at this time. Thereby, opening and closing conditions for reducing variations in the thickness of the web W are analyzed and calculated.

At this time, the data calculation in the calculation unit 283 is performed only in the first case by referring to the data table stored in the ROM before the sheet manufacturing apparatus 1 is shipped. The second and subsequent data calculations are performed with reference to both the data table and the data stored in the RAM after the first time.

In step S13, the derived opening/closing conditions are stored in the RAM of the storage unit 284. In step S14, the derived opening/closing conditions are reflected, and the four opening/closing driving units 286 drive the corresponding shutter units 85 to change the opening/closing state including the degree of opening/closing of the opening 84.

Note that the first method and the second method described above can be selected by the operator. As described above, the opening/closing state of the opening 84 is controlled by the control unit 28.

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

Variations in the thickness of the web W in the width direction can be reduced. Specifically, the fibers pass through the plurality of openings 84 and are loosened and dispersed. By opening and closing the plurality of openings 84, the unevenness of the dispersed fibers is suppressed. Therefore, the fibers can be deposited relatively uniformly in the deposition section 102. That is, it is possible to provide a sheet manufacturing apparatus 1 that reduces variations in the thickness of the web W.

Each opening 84 is changed to an appropriate open/closed state depending on the user settings, the state of fiber accumulation, and the open/closed state of the opening 84. As a result, the opening/closing state is finely adjusted, so that it is possible to further suppress the unevenness of the dispersed fibers. Since it becomes possible to input user settings by referring to the display on the display unit 282, convenience for the operator is improved. Furthermore, since it has an automatic mode that eliminates operator judgment, the operator's convenience is further improved.

4. EXAMPLES AND COMPARATIVE EXAMPLES Hereinafter, the effects of the present invention will be explained in more detail with reference to Examples and Comparative Examples. Note that the present invention is not limited in any way by the following examples.

In the examples and comparative examples, variations in the thickness of the web W in the direction along the Y axis were evaluated. The specific steps are as follows. First, using the sheet manufacturing apparatus 1 described above, webs W were produced at a plurality of levels in which the opening and closing states of the openings 84 were changed. The distance of the web W at each level in the direction along the Y axis, that is, the width was 750 mm.

In Example 1, the openings 84 corresponding to the shutter parts 85b and 85c were fully opened, and the opening rate, which is the degree of opening and closing of the openings 84 corresponding to the shutter parts 85a and 85d, was set to 75%. Here, the opening ratio of the opening 84 is the open area ratio of the opening 84 where the opening ratio is 100% when the opening is fully open and the opening ratio is 0% when the opening is fully closed.

In Example 2, the openings 84 corresponding to the shutter sections 85b and 85c were fully opened, and the opening ratio of the openings 84 corresponding to the shutter sections 85a and 85d was set to 50%.

In Comparative Example 1, the openings 84 corresponding to the shutter portions 85a, 85b, 85c, and 85d were fully opened. In Comparative Example 2, the openings 84 corresponding to the shutter parts 85b and 85c were fully opened, and the openings 84 corresponding to the shutters 85a and 85d were fully closed.

Note that in this evaluation, since the sheet S was not manufactured from the web W, the addition of a binder and the like to the web W and the lamination using the first base material N1 and the second base material N2 were omitted.

Next, the produced web W was taken out and cut to have a length of 300 mm in the direction along the X axis. Next, the obtained rectangular web W of 750 mm x 300 mm was cut into 10 equal parts along the X axis. As a result, 10 strip-shaped webs W of 75 mm x 300 mm were obtained.

Ten strip-shaped webs W were numbered as measurement positions 1, 2, 3, . . . 9, 10 from the −Y direction to the +Y direction, and the weights of each were measured. The weight of each strip-shaped web W was converted into basis weight (g/m ² ), and a graph shown in FIG. 10 was prepared. The variation in the thickness of the web W in the direction along the Y axis was evaluated from the variation in basis weight at the measurement position.

As shown in FIG. 10, in Example 1, the variation in basis weight at the measurement position was the smallest. In Example 2, the above-mentioned variation was smaller than in Example 1. From the above, it has been shown that by finely adjusting the opening/closing state of the opening 84, variations in the thickness of the web W in the direction along the Y axis can be reduced.

In Comparative Example 1, the above-mentioned variation was larger than in Examples 1 and 2. In Comparative Example 2, the basis weight from measurement positions 4 to 7 was large, and the variation was large overall. In addition, in the sheet manufacturing apparatus 1, as shown in FIG. 3, the air flow F from the pipe 40 is bent at the supply member 42. Depending on the form of the supply member 42, the tendency of variation in the thickness of the web W in the direction along the Y-axis may change. Therefore, it is preferable to adjust the opening/closing state of the opening 84 as appropriate depending on various conditions.

DESCRIPTION OF SYMBOLS 1... Sheet manufacturing apparatus, 28... Control part, 81... Rotating shaft part, 83, 83a, 83b, 83c, 83d... Blade part, 84... Opening part, 85, 85a, 85b, 85c, 85d... Shutter part, 101... Dispersion section, 102...Deposition section, 281...Input section, 282...Display section, 283...Calculation section, 284...Storage section, 285, 285a, 285b, 285c, 285d...Sensor section, 286, 286a, 286b, 286c, 286d ...Opening/closing drive unit, W...Web.

Claims (4)

It has a dispersion section that disperses fibers, and a deposition section that deposits the dispersed fibers to form a web,
The dispersion section includes a blade section having a plurality of openings arranged corresponding to the width direction of the web,
The blade portion includes a shutter portion corresponding to each of the plurality of openings,
A sheet manufacturing apparatus, wherein each of the shutter sections individually opens and closes the corresponding opening. The dispersion section includes a rotating shaft section to which a plurality of the blade sections are attached,
The sheet manufacturing apparatus according to claim 1, wherein the plurality of blades rotate around the rotating shaft to disperse the fibers. The sheet manufacturing apparatus according to claim 1, wherein each of the shutter portions changes the open/close state including the degree of opening/closing in the corresponding opening. has a control section,
The control unit includes:
a sensor unit that detects the accumulation state of the fibers in the accumulation unit;
an opening/closing drive unit that changes the opening/closing state of the opening by the shutter unit;
an input section that accepts user settings including settings for the open/closed state;
a storage unit that stores data including the user settings, the stacking state, and the opening/closing state;
a calculation unit that calculates the data stored in the storage unit and issues an instruction to the opening/closing drive unit to change the opening/closing state;
The sheet manufacturing apparatus according to claim 3, further comprising a display unit that displays the data.

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