Fiber processing device, fibrous feedstock recycling device, and control method of a fiber processing device

Variation in the thickness of accumulated material is suppressed when material containing fiber is dispersed by the sieve and accumulated. A sheet manufacturing apparatus includes a drum that sieves defibrated material containing fiber, a first web former that accumulates first screened material discharged from the drum, and a processor that processes a first web accumulated in the first web former. During processing by the processor, the mesh belt operates at a first speed. When operation starts with the drum not operating, a startup operation including the mesh belt operating at a higher speed than the first speed in a first period after the drum starts is executed.

This application claims the benefit of Japanese Patent Application No. 2018-006742 filed Jan. 18, 2018. The disclosure of the prior application is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a fiber processing device, a fibrous feedstock recycling device, and a control method of a fiber processing device.

2. Related Art

A system for recycling feedstock containing fiber that executes a process of laying fiber in a web form is known from the literature. See, for example, JP-A-2017-154341, which describes dispersing material through holes in a sieve into air and accumulating the material on a mesh belt.

The configuration described in JP-A-2017-154341 disperses material through the holes in a sieve. Depending on the material that is dispersed and the state of the system in this configuration, the amount of material that passes through the holes in the sieve can vary greatly according to the operation of the sieve.

SUMMARY

This invention is directed to this problem, and an objective of the invention is to suppress variation in the thickness of the accumulated material when material containing fiber is dispersed by the sieve and accumulated.

To achieve the foregoing objective, a fiber processing device according to the invention has a sieve configured to screen material containing fiber; an accumulator configured to accumulate the material discharged from the sieve; and a processor configured to process the material accumulated on the accumulator. The fiber processing device operates the accumulator at a first speed during processing by the processor; and when starting from a state in which the sieve is stopped, executes a startup operation including a state in which the accumulator operates at a higher speed than the first speed in a first period after the sieve starts.

By operating the accumulator at a high speed, this configuration suppresses increasing the thickness of the material accumulated on the accumulator even if the amount of material discharged from the sieve increases.

In a fiber processing device according to another aspect of the invention, in the first period, the accumulator maintains a state of operating at a higher speed than the first speed.

In a fiber processing device according to another aspect of the invention, the accumulator has a receiver on which the material can accumulate in a sheet, and the receiver moves on a circulating path.

In a fiber processing device according to another aspect of the invention, during processing by the processor, the receiver operates at the first speed, and in the first period the operating speed of the receiver is maintained at a second speed greater than the first speed.

In a fiber processing device according to another aspect of the invention, when starting from a state in which the sieve is stopped, before the sieve starts, the operating speed of the receiver accelerates to a higher speed than the first speed, and in a second period after acceleration ends, a state in which the receiver operates at a higher speed than the first speed is maintained.

In a fiber processing device according to another aspect of the invention, when starting from a state in which the sieve is stopped, the startup operation executes with the material in the sieve.

In a fiber processing device according to another aspect of the invention, the sieve moves at a third speed and discharges the material from the sieve during processing by the processor; and when starting from a state in which the sieve is stopped, includes a state in the first period when the sieve operates at a different speed than the third speed.

In a fiber processing device according to another aspect of the invention, the sieve is cylindrical, openings are disposed in the outside surface of the sieve, and the sieve rotates on an axis of the cylinder.

Another aspect of the invention is a fibrous feedstock recycling device including a refiner configured to refine material containing fiber; a sieve configured to screen refined material acquired from the refiner; an accumulator configured to accumulate the refined material discharged from the sieve; and a processor configured to process the refined material accumulated on the accumulator. The accumulator operates at a first speed during processing by the processor, and when starting from a state in which the sieve is stopped, a startup operation including a state in which the accumulator operates at a higher speed than the first speed in a first period after the sieve starts executes.

By operating the accumulator at a high speed in the startup operation, this configuration suppresses increasing the thickness of the material accumulated on the accumulator even if the amount of material discharged from the sieve increases.

Another aspect of the invention is a control method of a fiber processing device including a sieve configured to screen material containing fiber, an accumulator configured to accumulate the material discharged from the sieve, a processor configured to process the material accumulated on the accumulator, and a driver configured to operate the accumulator to convey the material accumulated on the accumulator to the processor. The control method causes the accumulator to operate at a first speed during processing by the processor; and when starting from a state in which the sieve is stopped, causes the driver to execute a startup operation including a state in which the accumulator operates at a higher speed than the first speed in a first period after the sieve starts.

By operating the accumulator at a high speed in the startup operation, this configuration suppresses increasing the thickness of the material accumulated on the accumulator even if the amount of material discharged from the sieve increases.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the invention are described below with reference to the accompanying figures. Note that the embodiments described below do not limit the content of the embodiment described in the accompanying claims. All configurations described below are also not necessarily essential elements of the invention.

1. General Configuration of a Sheet Manufacturing Apparatus

FIG. 1schematically illustrates the configuration of a sheet manufacturing apparatus100according to the invention.

The sheet manufacturing apparatus100executes a recycling process of extracting fiber from a feedstock material MA containing fiber and making new sheets S from the fiber. The sheet manufacturing apparatus100can make multiple types of sheets S, and by mixing additives with the feedstock material MA according to the application of the sheets S, can adjust the paper strength and whiteness, or add color, scents, or functions such as fire retardancy to the sheets S. The sheet manufacturing apparatus100can also adjust the density, thickness, size, and shape of the sheets S. Typical examples of the sheets S include office paper in standard sizes such as A4 or A3, various kinds of sheet products such as cleaning sheets for cleaning flooring, sheets for cleaning up oil and grease, and sheets cleaning toilets, as well as paper plates and other products. The sheet manufacturing apparatus100is an example of a fibrous feedstock recycling device and a fiber processing device according to the invention.

The sheet manufacturing apparatus100includes a feedstock feeder10, shredder12, defibrator20, classifier40, first web former45, rotor49, mixing device50, air-laying device60, second web former70, conveyor79, sheet former80, and sheet cutter90. The shredder12, defibrator20, classifier40, and first web former45configure a defibration processor101that defibrates the feedstock material MA and acquires material used to make the sheets S. The rotor49, mixing device50, air-laying device60, second web former70, sheet former80, and sheet cutter90configure a sheet maker102that processes the material acquired by the defibration processor101and makes sheets S.

The feedstock feeder10in this example is an automatic sheet feeder that holds and continuously supplies the feedstock material MA to the shredder12. The feedstock material MA may be an material containing fiber, such as recovered paper, waste paper, and pulp sheets.

The shredder12has shredder blades14that cut the feedstock material MA supplied by the feedstock feeder10, shreds the feedstock material MA in air by the shredder blades14, and produces paper shreds a few centimeters square. The shape and size of the shreds is not specifically limited. A paper shredder, for example, may be used as the shredder12. The feedstock material MA shredded by the shredder12is then collected in a hopper9, and conveyed through a conduit2to the defibrator20.

The defibrator20defibrates the coarse shreds produced by the shredder12. Defibration is a process of breaking feedstock material MA containing bonded fibers into single fibers or a few intertwined fibers. The feedstock material MA may also be referred to as material to defibrate or defibration material. By the defibrator20defibrating the feedstock material MA, resin particles, ink, toner, bleeding inhibitors, and other materials included in the feedstock material MA can be expected to also separate from the fibers. The material that has past through the defibrator20is referred to as defibrated material.

In addition to defibrated fibers that have been separated, the defibrated material may contain additives that are separated from the fiber during defibration, including resin, ink, toner, and other color additives, bleeding inhibitors, and paper strengthening agents. The resin particles contained in the defibrated material is resin that is mixed to bind fibers together when the feedstock material MA was manufactured. The shape of the fiber in the defibrated material may be as strings or ribbons. The fiber contained in the defibrated material may be as individual fibers not intertwined with other fibers, or as clumps, which are multiple fibers tangled with other defibrated material into clumps. The defibrator20is an example of a refiner. The defibrated material MB described below is an example of refined material.

The defibrator20defibrates in a dry process. A dry process as used herein means that the defibration process is done in air instead of a wet solution. The defibrator20uses a defibrator such as an impeller mill in this example. More specifically, the defibrator20has a rotor (not shown in the figure), and a liner (not shown in the figure) positioned around the outside of the rotor, and the shreds go between the rotor and the liner and are defibrated.

The shreds are conveyed by an air current from the shredder12to the defibrator20. This air current may be generated by the defibrator20, or the air current may be produced by a blower (not shown in the figure) disposed upstream or downstream from the defibrator20in the conveyance direction of the shreds and defibrated material. The defibrated material is carried by the air current from the defibrator20through a conduit3to the classifier40. The air current conveying the defibrated material to the classifier40may be generated by the defibrator20or the air current from the blower described above may be used.

The classifier40separates the components of the defibrated material defibrated by the defibrator20by the size of the fiber. The size of the fiber primarily indicates the length of the fiber. The classifier40has an inlet42through which defibrated material is introduced to the drum41, and an exit44from which second screened material described below is discharged from the drum41. The exit44connects to the defibrator20through a conduit8, and the classifier40returns the second screened material through the conduit8to the defibrator20.

The first web former45forms a first web W1by forming the material separated by the classifier40into a web.

FIG. 2shows the basic configuration of the classifier40and first web former45, and shows the main parts thereof from the side.

As shown inFIG. 1andFIG. 2, the classifier40includes a drum41, and a housing43around the drum41.

The drum41in this example is configured with a sieve. More specifically, the drum41has mesh, a filter or a screen with openings that functions as a sieve. More specifically, the drum41is cylindrical, and is rotationally driven centered on the axis of the cylinder by a first sieve motor40a(driver, sieve driver). At least part of the circumferential surface of the drum41is mesh. The mesh of the drum41may be a metal screen, expanded metal made by expanding a metal sheet with slits formed therein, or punched metal, for example. InFIG. 2, reference numeral41aindicates the openings in the drum41. The operating speed at which the drum41operates by driving the first sieve motor40ais speed VB. This speed VB is also referred to as the rotational speed of the drum41. Note that the direction of rotation of the drum41is not limited to the direction shown inFIG. 2, and the drum41may be driven in reverse, or driven bidirectionally by the first sieve motor40aalternating the direction of rotation. In addition, speed VB is not limited to the speed in the direction indicated by the arrow inFIG. 2, and may indicate the speed of the drum41relative to when the drum41is not turning.

The drum41is an example of a sieve according to the invention. The defibrated material MB that is fed into the drum41, and the first screened material MC that is sieved through the openings41a, are examples of material.

The first web former45includes a mesh belt46, tension rollers47, and a suction device48. The mesh belt46is an endless metal belt, and is mounted around multiple tension rollers47. The mesh belt46circulates in a path configured by the tension rollers47. Part of the path of the mesh belt46is flat in the area below the drum41, and the mesh belt46forms a flat surface.

One of the tension rollers47is a drive roller47athat drives the mesh belt46. The drive roller47aturns as driven by a first belt motor47b, and drives the mesh belt46in the direction indicated by the arrow in the figure. The operating speed at which the mesh belt46operates by the drive power of the first belt motor47bis speed VA. This speed VA is also referred to as the conveyance speed of the mesh belt46.

A servo motor, stepper motor, or other known type of motor may be used for the first sieve motor40aand first belt motor47b. Gears, links, or other transfer mechanisms that transfer power may also be disposed between the first sieve motor40aand drum41, and between the drive roller47aand first belt motor47b.

The defibrated material MB introduced from the inlet42to the inside of the drum41is separated by rotation of the drum41into screened material that past through the openings41aof the drum41, and remnants that do not pass through the openings41a. The screened material that past through the openings41aincludes fiber or particles that are smaller than the openings41a, and is referred to below as first screened material MC. The remnants include, for example, fibers, undefibrated shreds, and clumps that are larger than the openings41a, and are referred to as second screened material below. The first screened material MC descends inside the housing43and falls onto the first web former45. As described above, the second screened material is conveyed from the exit44through conduit8to the defibrator20.

By rotation of the drum41, the first screened material MC that passes through the openings41adescends inside the housing43to the mesh belt46. Numerous openings are also formed in the mesh belt46. Of the first screened material MC that descends from the drum41, components that are larger than the openings in the mesh belt46accumulate on the mesh belt46. Components of the first screened material MC that are smaller than the openings in the mesh belt46pass through the openings. The components that pass through the openings in the mesh belt46are referred to as third screened material D. The third screened material D contains fibers in the defibrated material that are shorter than the openings in the mesh belt46, as well as resin particles, and particles of ink, toner, bleeding inhibitors and other material that is separated from the fibers by the defibrator20. The first web former45in this example is an example of an accumulator according to the invention, and the mesh belt46is an example of a receiver in the invention. The first sieve motor40ais an example of a sieve driver, and the first belt motor47b is an example of a driver.

The suction device48pulls air from below the mesh belt46. The suction device48is connected through a conduit23to a first dust collector27. The first dust collector27has a filter for separating the third screened material D from the air current. Downstream from the first dust collector27is a first collection blower28, and the first collection blower28suctions air from the first dust collector27.

This configuration suctions small third screened material D from the first screened material MC that descended to the mesh belt46by the suction of the first collection blower28, and collects the third screened material D by the filter of the first dust collector27. The air that passes through the filter of the first dust collector27is discharged from a conduit29.

Because the air current suctioned by the suction device48pulls the first screened material MC descending from the drum41to the mesh belt46, the air current has the effect of promoting accumulation of the first screened material MC. The first screened material MC accumulated on the mesh belt46accumulates in a web, forming a first web W1.

Of the components of the first screened material MC, the first web W1comprises mainly fibers that are larger than the openings in the mesh belt46, and is a fluffy web containing much air. The first web W1is conveyed by movement of the mesh belt46to the rotor49.

Referring again toFIG. 1, the rotor49has a base49aconnected to a driver such as a motor (not shown in the figure), and fins49bprotruding from the base49a, and when the base49aturns indirection of rotation R indicated by the arrow, the fins49brotate around the base49a. The fins49bin this example are flat blades. In the example inFIG. 1, there are four fins49bdisposed equidistantly around the base49a.

The rotor49is disposed at the end of the flat part of the path of the mesh belt46. Because the path of the mesh belt46curves down at this end, the mesh belt46also curves and moves down. As a result, the first web W1conveyed by the mesh belt46extends forward from the mesh belt46and contacts the rotor49. The first web W1is then broken up by the fins49bstriking the first web W1, and reduced to small clumps of fiber. These clumps then travel through the conduit7located below the rotor49, and are conveyed to the mixing device50. Because the first web W1is a soft, fluffy structure of fiber accumulated on the mesh belt46as described above, the first web W1is easily broken up by collision with the rotor49.

The rotor49is positioned so that the fins49bcan contact the first web W1but the fins49bdo not touch the mesh belt46. The distance between the fins49band the mesh belt46at the closest point is preferably greater than or equal to 0.05 mm and less than or equal to 0.5 mm.

The mixing device50mixes the first screened material with an additive. The mixing device50has an additive supplier52that supplies an additive, a conduit54through which the first screened material MC and additive flow, and a mixing blower56.

One or more additive cartridges52astoring additives are installed to the additive supplier52. The additive cartridges52amay be removably installed to the additive supplier52. The additive supplier52includes an additive extractor52bthat extracts additive from the additive cartridges52a, and an additive injector52cthat injects the additive extracted by the additive extractor52binto the conduit54.

The additive extractor52bhas a feeder (not shown in the figure) that feeds additive in a powder or particulate form from inside the additive cartridges52a, and removes additive from some or all of the additive cartridges52a. The additive removed by the additive extractor52bis conveyed to the additive injector52c.

The additive injector52cholds the additive removed by the additive extractor52b. The additive injector52chas a shutter (not shown in the figure) that opens and closes the connection to the conduit54, and when the shutter is open, the additive extracted by the additive extractor52bis fed into the conduit54.

The additive supplied from the additive supplier52includes resin (binder) that binds multiple fibers together when heated. The resin contained in the additive melts when passing through the sheet former80and binds multiple fibers together. The resin may be a thermoplastic resin or thermoset resin, such as AS resin, ABS resin, polypropylene, polyethylene, polyvinyl chloride, polystyrene, acrylic resin, polyester resin, polyethylene terephthalate, polyethylene ether, polyphenylene ether, polybutylene terephthalate, nylon, polyimide, polycarbonate, polyacetal, polyphenylene sulfide, and polyether ether ketone. These resins may be used individually or in a desirable combination.

The additive supplied from the additive supplier52may contain components other than resin for binding fibers. For example, depending on the type of sheet being manufactured, the additive also include a coloring agent for coloring the fiber, an anti-blocking agent to prevent agglomeration of fibers and agglomeration of resin, or a flame retardant for making the fiber difficult to burn. The additive may also be in the form of fibers or particles.

The mixing blower56produces an air current flowing through a conduit54connecting7to the air-laying device60. The first screened material MC conveyed from the7into the conduit54, and the additive supplied by the additive supply device52to the conduit54, are mixed as they pass through the mixing blower56.

The mixing blower56in this example can be configured with a motor (not shown in the figure), blades (not shown in the figure) that turn as driven by the motor, and a case (not shown in the figure) housing the blades, and may be a configuration in which the blades and case are connected. In addition, to blades for producing an air current, the mixing blower56may also include a mixer for mixing the first screened material and the additive. The mixture combined by the mixing device50is then conveyed by the air current produced by the mixing blower56to the air-laying device60, and introduced through the inlet62to the air-laying device60.

The air-laying device60detangles and causes the fibers in the mixture to disperse in air while precipitating to the second web former70. If the additive supplied from the additive supply device52is fibrous, these additive fibers are also detangled by the air-laying device60and descend to the second web former70. The second web former70accumulates the mixture precipitating from the air-laying device60, forming a second web W2.

FIG. 3shows the basic configuration of the air-laying device60and second web former70, and shows the main parts thereof from the side.

As shown inFIG. 1andFIG. 3, the air-laying device60includes a drum61, and a housing63around the drum61.

The air-laying device60includes a drum61, and a housing63that houses the drum61. The drum61is configured as a cylindrical structure.

Like the drum41described above, drum61in this example is configured with a sieve. More specifically, the drum61has mesh, a filter or a screen with openings that functions as a sieve. More specifically, the drum61is cylindrical, and is rotationally driven centered on the axis of the cylinder by second sieve motor60a(driver, sieve driver). At least part of the circumferential surface of the drum61is mesh. The mesh of the drum61may be a metal screen, expanded metal made by expanding a metal sheet with slits formed therein, or punched metal, for example. The openings in the drum61are identified as holes61a. The drum61turns as driven by the second sieve motor60a, functions as a sieve, and the mixture detangled by rotation of the drum61passes through the holes61aand descends. The mixture that passes through the inlet62is referred to as mixture MX below.

The operating speed at which the drum61operates by driving the second sieve motor60ais speed VD. This speed VD is also referred to as the rotational speed of the drum61. Note that the direction of rotation of the drum61is not limited to the direction shown inFIG. 3, and the drum61may be driven in reverse, or driven bidirectionally by the second sieve motor60aalternating the direction of rotation. In addition, speed VD is not limited to the speed in the direction indicated by the arrow inFIG. 3, and may indicate the speed of the drum61relative to when the drum61is not turning.

The second web former70is located below the drum61. The second web former70in this example includes a mesh belt72, tension rollers74, and a suction mechanism76.

The mesh belt72is an endless metal belt similar to the mesh belt46described above, and is mounted around multiple tension rollers74. The mesh belt72circulates in a path configured by the tension rollers74. Part of the path of the mesh belt72is flat in the area below the drum61, and the mesh belt72forms a flat surface. There are also many holes in the mesh belt72.

One of the tension rollers74is a drive roller74athat drives the mesh belt72. The drive roller74aturns as driven by a second belt motor74b, and drives the mesh belt74in the direction indicated by the arrow in the figure. The operating speed at which the mesh belt74operates by the drive power of the second belt motor74bis speed VC. This speed VC is also referred to as the conveyance speed of the mesh belt72.

A servo motor, stepper motor, or other known type of motor may be used for the second sieve motor60aand second belt motor74b. Gears, links, or other transfer mechanisms that transfer power may also be disposed between the second sieve motor60aand drum61, and between the drive roller74aand second belt motor74b.

The mixture MX inside the drum61passes through the holes61aby rotation of the drum61, and descends to the mesh belt72. Of the mixture MX descending from the drum61, components larger than the holes in the mesh belt72accumulate on the mesh belt72. Components of the mixture that are smaller than the holes in the mesh belt72pass through the holes.

A suction mechanism76is connected to a conduit66. The conduit66is connected through a second dust collector67to the second collection blower68. The second dust collector67has a filter that collects particles and fiber that pass through the mesh belt72. The second collection blower68is a blower that suctions air through the conduit66, and discharges the suctioned air outside the sheet manufacturing apparatus100or to a specific place in the sheet manufacturing apparatus100.

The suction mechanism76pulls air from below the mesh belt72by the suction of the second collection blower68, and collects particles and fiber contained in the suctioned air by the second dust collector67. The air current suctioned by the second collection blower68pulls the mixture descending from the drum61to the mesh belt72, and has the effect of promoting accumulation of the mixture on the mesh belt72. The air current suctioned by the suction device48creates a down flow in the path of the mixture descending from the drum61, and can be expected to have the effect of preventing the precipitating fibers from becoming tangled. The mixture MX accumulated on the support surface71is laid in a web on the flat part of the mesh belt72, forming a second web W2.

Referring again toFIG. 1, a wetting device78is disposed to the conveyance path of the mesh belt72downstream from the air-laying device60. The wetting device78is a mist humidifier that produces and supplies a water mist to the mesh belt72. The wetting device78in this example has a tank that holds water, and an ultrasonic vibrator that converts the water to mist. Because the moisture content of the second web W2can be adjusted by the mist supplied by the wetting device78, the mist can be expected to suppress accretion of fiber on the mesh belt72due to static electricity.

The second web W2is then conveyed by the conveyor79, separates from the mesh belt72, and is conveyed to the sheet former80. The conveyor79in this example has a mesh belt79a, rollers79b, and a suction mechanism79c. The suction mechanism79chas a blower (not shown in the figure), and produces an air current upward through the mesh belt79aby the suction of the blower. The second web W2is separated from the mesh belt72and pulled to the mesh belt79aby this air current. The mesh belt79amoves by rotation of the rollers79b, and conveys the second web W2to the sheet former80.

By applying heat to the second web W2, the sheet former80binds fibers recovered from the first screened material and contained in the second web W2through the resin contained in the additive.

The sheet former80has a compression device82that compresses the second web W2, and a heating device84that heats the second web W2after compression by the compression device82.

The compression device82comprises a pair of calender rolls85. The compression device82has a hydraulic press mechanism (not shown in the figure) that applies nip pressure to the calender rolls85, and a motor or other driver (not shown in the figure) that causes the calender rolls85to rotate in the direction of the heating device84. The compression device82compresses and conveys the second web W2to the heating device84with a specific nip pressure by the calender rolls85.

The heating device84includes a pair of heat rollers86. The heating device84also has a heater (not shown in the figure) that heats the surface of the heat rollers86to a specific temperature, and a motor or other driver (not shown in the figure) that causes the heat rollers86to rotate in the direction of the sheet cutter90. The heating device84holds and heats the second web W2compressed to a high density by the compression device82, and conveys the heated second web W2to the sheet cutter90. The second web W2is heated in the heating device84to a temperature greater than the glass transition temperature of the resin contained in the second web W2, forming a sheet S.

The sheet cutter90cuts the sheet S formed by the sheet former80. In this example, the sheet cutter90has a first cutter92that cuts the sheet S crosswise to the conveyance direction of the sheet S indicated by the arrow F in the figure, and a second cutter94that cuts the sheet S parallel to the conveyance direction F. The sheet cutter90cuts the length and width of the sheet S to a specific size, forming single sheets. The single sheets S cut by the sheet cutter90are then stored in the discharge tray96. The discharge tray96may be a tray or stacker for holding the manufactured sheets, and the sheets S discharged to the tray can be removed and used by the user.

Parts of the sheet manufacturing apparatus100embody a defibration processor101and a sheet maker102. The defibration processor101includes at least the defibrator20, and may include the classifier40and first web former45.

The defibration processor101makes defibrated material from feedstock material MA, or forms the defibrated material into a web configuration to make a first web W1. The work product of the defibration processor101may be conveyed through the rotor49to the mixing device50, or removed from the sheet manufacturing apparatus100without passing through the rotor49and stored. This work product can also be sealed in specific packages in a form ready for shipping or sale.

The sheet maker102is a functional device for making the work product manufactured by the defibration processor101into sheets S, and may be referred to as a processor. The sheet maker102includes the mixing device50, air-laying device60, second web former70, conveyor79, sheet former80and sheet cutter90, and may also include the rotor49. The sheet maker102may also include the additive supply device52.

The sheet manufacturing apparatus100may be configured with the defibration processor101and sheet maker102as a single integrated system, or with the defibration processor101and sheet maker102separate. In this case, the defibration processor101is an example of a fibrous feedstock recycling device according to the invention. The sheet maker102is an example of a sheet forming device that processes defibrated material into sheets. Each of these components may also be conceived of as processing devices.

1-2. First Web W1Forming Conditions

The forming conditions of the first web W1formed by the first web former45are described below with reference toFIG. 2.

The thickness of the first web W1is determined by the amount of first screened material MC, which is the material supplied to the mesh belt46, and the amount of movement of the mesh belt46per unit time. The amount of movement of the mesh belt46per unit time is speed VA shown in the figure.

One factor determining the amount of first screened material MC supplied to the mesh belt46, that is, the amount of first screened material MC passing through the openings41a, is the speed VB of the drum41. As speed VB increases, the defibrated material MB is more quickly defibrated in the drum41, and the first screened material MC passes more easily through the openings41a. In addition, the greater the speed VB, the more easily the first screened material MC passes the openings41a. Therefore, the amount of first screened material MC passing the openings41aincreases as the speed VB increases.

The amount of first screened material MC passing the openings41achanges when the drum41starts moving from a stop. Because rotation of the drum41produces friction between the fibers of the first screened material MC inside the drum41, the first screened material MC also becomes charged. If the first screened material MC agglomerates due to this static electricity, it becomes more difficult for the first screened material MC to pass the openings41a.

On the other hand, when the drum41is stopped, the charge of the charged first screened material MC is discharged, and clumps of fiber in the first screened material MC break apart. Therefore, when the drum41starts turning from a stop, that is, when the drum41starts operating, the first screened material MC passes easily through the openings41a. The amount of first screened material MC passing the openings41atherefore temporarily increases at this time.

The amount of first screened material MC passing the openings41ais also affected by the humidity in the drum41. Humidity as used here can be referred to as relative humidity (RH). If the humidity inside the drum41is high, charging of the fibers in the first screened material MC is reduced, fiber agglomeration is suppressed, and the volume of fiber clumps to be broken up is low. Therefore, the higher the humidity inside the drum41, the less variation there is in the amount of first screened material MC passing the openings41a.

In addition, if the humidity inside the drum41is low, reducing charging of the fibers in the first screened material MC is more difficult, fiber agglomeration increases greatly, and the volume of fiber clumps to be broken up is great. Therefore, the lower the humidity inside the drum41, the greater the variation is in the amount of first screened material MC passing the openings41a.

The amount of first screened material MC passing the openings41aalso varies according to the length of the fiber in the first screened material MC. Short fibers pass through the openings41aeasily. Therefore, the shorter the fibers in the first screened material MC, the greater the amount of first screened material MC that passes the openings41a.

The greatest factor determining the amount of first screened material MC supplied from the drum41to the mesh belt46is therefore the speed VB of the drum41. Factors that change the amount of first screened material MC include whether or not the drum41is starting up, the humidity inside the drum41, and the length of fiber in the first screened material MC.

If the thickness of the first web W1varies, the amount of material supplied to processes downstream from the first web former45may vary, affecting the quality of the sheets S manufactured by the sheet manufacturing apparatus100.

The controller150of the sheet manufacturing apparatus100therefore executes a control process that suppresses variation in the thickness of the first web W1.

To execute control related to the thickness of the first web W1, the sheet manufacturing apparatus100has a first belt speed detector322(FIG. 4) for detecting the speed VA, and a first sieve speed detector321(FIG. 4) for detecting speed VB.

The sheet manufacturing apparatus100can also detect the humidity inside the drum41. For example, in this configuration the sheet manufacturing apparatus100has a first temperature/humidity detector323(humidity detector). The first temperature/humidity detector323can be configured by a sensor unit having a temperature sensor and a humidity sensor. The temperature sensor may be a thermistor, resistance temperature detector, thermocouple, or IC temperature sensor, for example. The humidity sensor may be any configuration capable of detecting relative humidity, such as a resistance humidity sensor or a capacitance humidity sensor. The first temperature/humidity detector323detects the temperature and the relative humidity of the space inside the drum41. The first temperature/humidity detector323may output the temperature and humidity detection values as analog signal or as digital data indicating the detected values. The detected temperature and detected humidity may also be output as a combined value.

The sheet manufacturing apparatus100also has a first thickness detector324. The first thickness detector324is a sensor that detects the thickness of the first web W1. For example, the first thickness detector324may be an optical thickness sensor that has a light source and a photosensor, emits light to the first web W1, and detects the amount of light passing the first web W1to detect the thickness of the first web W1. The first thickness detector324may also be a contact thickness sensor having a probe that contacts the first web W1, and an encoder that detects the position of the probe, and detects the distance between the surface of the first web W1and the surface of the mesh belt46. The first thickness detector324may also be an ultrasonic thickness sensor, or a sensor that detects thickness by another method.

The controller110may also control adjusting the thickness of the first web W1based on the output of the first thickness detector324. For example, if the thickness detected by the first thickness detector324is outside a predetermined range, the controller110may stop the sheet manufacturing apparatus100or issue a warning.

1-3. Second Web Former Configuration

As shown inFIG. 3, the sheet manufacturing apparatus100may also have a second temperature/humidity detector333as a configuration for detecting the humidity inside the drum61. Like the first temperature/humidity detector323, the second temperature/humidity detector333can be configured by a sensor unit having a temperature sensor and a humidity sensor. The temperature sensor may be a thermistor, resistance temperature detector, thermocouple, or IC temperature sensor, for example. The humidity sensor may be any configuration capable of detecting relative humidity, such as a resistance humidity sensor or a capacitance humidity sensor. The second temperature/humidity detector333detects the temperature and the relative humidity of the space inside the drum61. The second temperature/humidity detector333may output the temperature and humidity detection values as analog signal or as digital data indicating the detected values. The detected temperature and detected humidity may also be output as a combined value.

The sheet manufacturing apparatus100also has a second thickness detector334. The second thickness detector334is a sensor that detects the thickness of the second web W2. For example, the second thickness detector334may be an optical thickness sensor that has a light source and a photosensor, emits light to the second web W2, and detects the amount of light passing the second web W2to detect the thickness of the second web W2. The second thickness detector334may also be a contact thickness sensor having a probe that contacts the second web W2, and an encoder that detects the position of the probe, and detects the distance between the surface of the second web W2and the surface of the mesh belt72. The second thickness detector334may also be an ultrasonic thickness sensor, or a sensor that detects thickness by another method.

The controller110may also control adjusting the thickness of the second web W2based on the output of the second thickness detector334. For example, if the thickness detected by the second thickness detector334is outside a predetermined range, the controller110may stop the sheet manufacturing apparatus100or issue a warning.

1-4. Controller Configuration

FIG. 4is a block diagram of the control system of the sheet manufacturing apparatus100.

The sheet manufacturing apparatus100has a controller110that has a main processor111configured to control parts of the sheet manufacturing apparatus100.

The controller110has a main processor111, ROM (Read Only Memory)112, and RAM (Random Access Memory)113.

The main processor111is embodied by a processor such as a CPU (central processing unit), and controls parts of the sheet manufacturing apparatus100by running a basic control program stored in ROM112. The main processor111may also be configured as a system chip including ROM112, RAM113, or other peripheral circuits, or other IP cores.

ROM112nonvolatilely stores programs executed by the main processor111.

RAM113provides working memory used by the main processor111, and temporarily stores programs the main processor111runs and data that is processed.

Nonvolatile storage120stores programs the main processor111executes, and data the main processor111processes.

The display panel116is an LCD or other type of display panel, and in this example is disposed externally to the sheet manufacturing apparatus100. The display panel116displays the operating status of the sheet manufacturing apparatus100, various settings, and warnings, for example.

The touch sensor117detects user operations by touch or pressure. In this example, the touch sensor117is disposed over the display surface of the display panel116, and detects operations on the display panel116. In response to operations, the touch sensor117outputs to the main processor111operating data including the operating position and the number of operating positions. Based on output from the touch sensor117, the main processor111detects operation of the display panel116, and acquires the operating positions. The main processor111enables GUI (graphical user interface) operations based on the operating position detected by the touch sensor117, and the display data122that was displayed on the display panel116when the operation was detected.

The controller110is connected through a sensor interface114to sensors disposed to parts of the sheet manufacturing apparatus100. The sensor interface114is an interface that acquires detection values output by the sensors, and inputs to the main processor111. The sensor interface114may include an A/D converter that converts analog signals output by the sensors to digital data. The sensor interface114may also supply drive current to the sensors. The sensor interface114may also include circuits that acquire sensor output values according to the sampling frequency controlled by the main processor111, and output to the main processor111.

The sensor interface114is also connected to a feedstock sensor301, and a paper discharge sensor302, for example. Also connected to the sensor interface114are the first sieve speed detector321, first belt speed detector322, first temperature/humidity detector323, and first thickness detector324. Additionally, the second sieve speed detector331, second belt speed detector332, second temperature/humidity detector333, and second thickness detector334are connected to the sensor interface114.

The first sieve speed detector321detects speed VB. The first sieve speed detector321may be configured with a rotary encoder and a sensor that contacts the rotary shaft or surface of the drum41, and detects the rotational speed. The first sieve speed detector321may also be a circuit disposed inside the first sieve motor40a, or configured as part of the first sieve motor40a, that outputs a signal indicating the number of revolutions or the rotational speed of the first sieve motor40a. The controller110may also function as the first sieve speed detector321, and calculate the rotational speed of the first sieve motor40abased on the drive current of the first sieve motor40a.

The second sieve speed detector331detects speed VD, which is the operating speed of the drum61. The second sieve speed detector331may be configured identically to the first sieve speed detector321.

The first belt speed detector322detects speed VA, which is the operating speed of the mesh belt46. The first belt speed detector322detects the speed of mesh belt46movement, the rotational speed of the tension rollers74, or the rotational speed of the first belt motor47b. The first belt speed detector322may be configured with a speed sensor or rotary encoder. The first belt speed detector322may also be a circuit disposed inside the first belt motor47b, or configured as part of the first belt motor47b, that outputs a signal indicating the number of revolutions or the rotational speed of the first belt motor47b. The controller110may also function as the first belt speed detector322, and calculate the rotational speed of the first belt motor47bbased on the drive current of the first belt motor47b.

The second belt speed detector332detects speed VC, which is the operating speed of the mesh belt72. The second belt speed detector332may be configured identically to the second sieve speed detector331.

The feedstock sensor301detects the remaining amount of feedstock MA in the feedstock feeder10. The paper discharge sensor302detects how many sheets S are stored in the tray or stacker of the tray96.

The controller110is connected to the drivers of the sheet manufacturing apparatus100through a driver interface115. The drivers of the sheet manufacturing apparatus100include motors, pumps, and heaters, for example. The driver interface115may be a configuration directly connected to a motor, or connected to a drive circuit or drive chip (IC chip) that supplies drive current to a motor.

A shredder311, defibrator312, additive supplier313, blower314, humidifier315, drum driver316, separator317, and sheet cutter318are connected to the driver interface115as control objects of the controller110.

The shredder311in this example includes a motor or other drive device for turning the shredder blades14.

The defibrator312includes a motor or other drive device for turning the rotor (not shown in the figure) of the defibrator20.

The additive supplier313includes drivers such as a motor that drives a screw feeder for out-feeding additive, and a motor or actuator that opens and closes the shutters.

The blowers314include the first collection blower28, mixing blower56, and second collection blower68. These blowers may individually connect to the driver interface115.

The humidifier315includes the ultrasonic vibration generator (not shown in the figure) of the wetting device78, a fan (not shown in the figure), and a pump (not shown in the figure).

The drum driver316includes drivers such as a motor for turning drum41, and a motor for turning drum61.

The separator317includes a driver such as a motor (not shown in the figure) for turning the rotor49.

The sheet cutter318includes motors (not shown in the figure) for respectively operating the blades of the first cutter92and second cutter94of the sheet cutter90.

A motor for driving the calender rolls85, and a heater for heating the heat rollers86, may also be connected to the driver interface115.

A first sieve motor40a, first belt motor47b, second sieve motor60a, and second belt motor74bare also connected to the driver interface115. The controller110can control these motors to start turning and stop turning. The controller110can also control the speed of the first sieve motor40aand first belt motor47b.

FIG. 5is a function block diagram of the controller110.

The controller110embodies various function units by the cooperation of hardware and software resulting from a main processor111running a program.FIG. 5shows the functions of the main processor111embodying these function units as controller150. The controller110also configures storage160, which is a logical storage device, using the memory area of the nonvolatile storage120. The storage160may be configured using memory areas in ROM112and RAM113.

The controller150has a detection controller151and a drive controller152. These controllers are embodied by the main processor111running a program. The controller110may also execute an operating system (OS) as a basic control program for controlling the sheet manufacturing apparatus100and configuring a platform for running application programs. In this case, the function units of the controller150may be embodied as application programs.

InFIG. 5, detectors controlled by the controller150include the first sieve speed detector321, first belt speed detector322, first temperature/humidity detector323, and first thickness detector324. A second sieve speed detector331, second belt speed detector332, second temperature/humidity detector333, and second thickness detector334are also shown. These sensors are collectively referred to as sensors300.

FIG. 5also shows the first sieve motor40a, first belt motor47b, second sieve motor60a, and second belt motor74bas drivers controlled by the controller150. These other drivers are collectively referred to as driver310.

The storage160stores data processed by the controller150. In this example, the storage160more specifically stores settings data161, reference data162, and speed setting data163.

The settings data161is generated by operating the touch sensor117, or based on commands and data input through a communication interface (not shown in the figure) of the controller110, and stored in storage160.

The settings data161include various settings related to operation of the sheet manufacturing apparatus100. For example, the settings data161may include the number of sheets S manufactured by the sheet manufacturing apparatus100, the type and color of sheets S, operating conditions for parts of the sheet manufacturing apparatus100, and other settings. The settings data161also includes a setting input through the touch sensor117related to the length of fiber in the feedstock material MA the sheet manufacturing apparatus100processes. For example, when the feedstock material MA is sheets S that were manufactured by the sheet manufacturing apparatus100and contain fiber that has been processed multiple times by the sheet manufacturing apparatus100, and when the feedstock material MA contains fiber sourced from deciduous trees, the feedstock material MA contains short fibers. The settings data161may include values for input items related to the length of fiber in the feedstock material MA, such as the type of feedstock material MA, as data related to the length of fiber in the feedstock material MA.

The reference data162includes reference values for evaluating the operating conditions for making sheets S in the sheet manufacturing apparatus100. More specifically, the reference data162includes a reference value for determining whether the humidity detected by the first temperature/humidity detector323is high or low.

The reference data162may also include reference values for evaluations related to the speed detected by the first sieve speed detector321, first belt speed detector322, second sieve speed detector331, and second belt speed detector332.

The reference data162may also include standards for evaluating the detection values output from the first thickness detector324and second thickness detector334.

The reference values included in the reference data162may be a single value, or range values including maximum and minimum values for a range.

The speed setting data163includes data for the controller150to control the speed of the first belt motor47b. When the sheet manufacturing apparatus100starts, the controller150causes the first sieve motor40aand first belt motor47bto accelerate, and operates the drum41and mesh belt46at a speed suitable for making a sheet S. The sheet manufacturing apparatus100starting means the sheet manufacturing apparatus100starting the operation for making a sheet S from a stop. To suppress variation in the thickness of the first web W1in this process, the controller150increases speed VA from speed 0.

The speed setting data163includes data related to speed when accelerating the mesh belt46from a stopped state to speed VA. For example, the speed setting data163includes data related to speed conditions defining the correlation between time and speed VA when accelerating the mesh belt46from speed 0. The speed conditions may be conditions defining the change in speed, which may be referred to as the speed pattern.

The detection controller151controls detected by the sensors300, and acquires the detection values from the sensors. The detection controller151also acquires the detection values from the first sieve speed detector321, first belt speed detector322, first temperature/humidity detector323, and first thickness detector324. The detection controller151also acquires the detection values from the second sieve speed detector331, second belt speed detector332, second temperature/humidity detector333, and second thickness detector334.

By controlling the driver310based on the detection values of the sensors300acquired by the detection controller151, the drive controller152operates parts of the sheet manufacturing apparatus100according to the values in the settings data161, and manufactures a sheet S.

The drive controller152drives the first sieve motor40a, first belt motor47b, second sieve motor60a, and second belt motor74b. Based on the detection values of the first sieve speed detector321and first belt speed detector322acquired by the detection controller151, the drive controller152controls the speed of the first sieve motor40aand first belt motor47b. As a result, speed VA and speed VB are adjusted to the set speeds.

Based on the detection values of the second sieve speed detector331and second belt speed detector332acquired by the detection controller151, the drive controller152controls the speed of the second sieve motor60aand second belt motor74b. As a result, speed VC and speed VD are adjusted to the set speeds.

The drive controller152sets the speed conditions of the first belt motor47bwhen starting the drum41and mesh belt46from a stop. The speed conditions are data defining the rate of acceleration when accelerating the first belt motor47bfrom a full stop. The drive controller152sets the speed conditions based on the detection values of the first temperature/humidity detector323acquired by the detection controller151, the settings data161, reference data162, and speed setting data163.

1-5. Sheet Manufacturing Apparatus Operation

FIG. 6andFIG. 7are flow charts of the operation of the sheet manufacturing apparatus100, and describe the operation of starting the sheet manufacturing apparatus100from when the sheet manufacturing apparatus100is stopped. The operation shown inFIG. 6andFIG. 7is executed by the drive controller152of the controller150.

The controller150first executes a setup process related to first belt motor47boperation (step ST1). The setup process of step ST1is a process of making settings related to the speed of the first belt motor47bwhen the first sieve motor40astarts operating. This setup process is described below with reference toFIG. 7.

After the setup process, the controller150starts the startup sequence (step ST2). The startup sequence is a sequence of operations sequentially starting parts of the sheet manufacturing apparatus100from the stopped state of the sheet manufacturing apparatus100. More specifically, the startup sequence starts the shredder12, defibrator20, classifier40, first web former45, rotor49, mixing device50, air-laying device60, second web former70, sheet former80, and sheet cutter90from the stopped state.

When the startup sequence starts, the controller150controls the humidifier315to start operation of the wetting device78(step ST3). If the sheet manufacturing apparatus100has devices other than the wetting device78that add humidity, the controller150also starts those devices in step ST3.

Next, the controller150starts the blower314(step ST4), and starts the defibrator312and thereby starts the defibrator20turning (step ST5). The defibrator20then accelerates to a previously set speed, and thereafter operates at a constant speed.

Next, the controller150starts the shredder311(step ST6). After step ST6, feedstock containing fiber is supplied to the shredder311.

The controller150also starts the first sieve motor40aand first belt motor47b, and starts driving the drum41and mesh belt46of the classifier40(step ST7). In step ST7, the first belt motor47bis started and the speed of the first belt motor47bincreases according to the conditions set in step ST1. Also in step ST7, the controller150starts the first sieve motor40a, and accelerates the first sieve motor40aaccording to a previously set target speed and rate of acceleration.

Next, the controller150starts the second sieve motor60aand second belt motor74b, and starts the drum61and mesh belt72(step ST8). The controller150then starts operation of the calender rolls85and heat rollers86of the sheet former80(step ST9), and completes the startup sequence.

FIG. 7is a flow chart of the setup process executes in step ST1inFIG. 6.

The controller150first determines if there is defibrated material MB inside the drum41(step ST21). Whether or not there is any defibrated material MB may be determined based on input from the touch sensor117, for example.

If there is no defibrated material MB inside the drum41(step ST21: NO), the controller150sets a first speed condition as the condition for accelerating the speed of the first belt motor47b(step ST22), and ends the setup process.

If there is defibrated material MB inside the drum41(step ST21: YES), the controller150determines whether or not the humidity detected by the first temperature/humidity detector323is greater than or equal to the reference value contained in the reference data162(step ST23). If the humidity is greater than or equal to the reference value (step ST23: YES), the controller150determines if the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data162(step ST24).

If the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data162(step ST24: YES), the controller150sets a second speed condition as the condition for accelerating the speed of the first belt motor47b(step ST25), and ends the setup process.

If the length of fiber contained in the defibrated material MB is shorter than the reference value (step ST24: NO), the controller150sets a third speed condition as the condition for accelerating the speed of the first belt motor47b(step ST26), and ends the setup process.

However, if the humidity is less than the reference value (step ST23: NO), the controller150determines if the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data162(step ST27).

If the length of fiber contained in the defibrated material MB is greater than or equal to the reference value (step ST27: YES), the controller150sets a fourth speed condition as the condition for accelerating the speed of the first belt motor47b(step ST28), and ends the setup process.

If the length of fiber contained in the defibrated material MB is shorter than the reference value (step ST27: NO), the controller150sets a fifth speed condition as the condition for accelerating the speed of the first belt motor47b(step ST28), and ends the setup process.

The first to fifth speed conditions are basic conditions for accelerating from zero to speed VB when starting the drum41, and include a target speed for the first belt motor47b, and either the time for acceleration to the target speed or the acceleration rate of the first belt motor47b.

FIG. 8is a graph showing an example of the operating speed VA of the mesh belt46and change in thickness of the first web W1.FIG. 8(1) indicates the speed VA detected by the first belt speed detector322, (2) indicates the detection value of the first web W1detected by the first thickness detector324, and (3) indicates the speed VB of the drum41detected by the first sieve speed detector321.

The Y-axes indicate speeds VA and VB, and the thickness of the first web W1, and coordinate 0 on the Y-axis indicates speed 0 (stopped) and the first web W1thickness 0. The X-axis indicates time, and coordinate 0 indicates the beginning of the startup sequence. After the startup sequence starts, the time at which the first sieve motor40aand first belt motor47bstart operating is time T1.

The target value set for the thickness of the first web W1is thickness TH1. In this operating example, the thickness of the first web W1is ideally held constant at thickness TH1. The thickness TH1is set to a value in the range 2 mm to 10 mm in this example, but may be set thicker or thinner.

FIG. 8is an example of a the controller150controlling the first sieve motor40aand first belt motor47baccording to the first speed condition.

In the examples shown inFIG. 8andFIG. 9toFIG. 11described below, the target speed for speed VA is set to speed V1. This target speed V1is the speed VA when the sheet manufacturing apparatus100makes sheets S, and is an example of a first speed in the invention. The target speed V1may be set to a value in the range 50 mm/s-1000 mm/s, for example, but may be slower or faster. The speed VB of the drum41is set to a value in the range 50 rpm-1000 rpm for example.

As shown inFIG. 8, after starting the first sieve motor40aat time T1, the controller150accelerates the first sieve motor40auntil speed VB reaches target speed V11, and thereafter holds speed VB at speed V11. This speed V11is the speed VB when the sheet manufacturing apparatus100manufactures sheets S, and is an example of a third speed in the invention.

Note that in this example the time from when the mesh belt46starts until speed VA reaches speed V11is referred to as the speed adjustment period.

The first speed condition is the condition enabling speed VA to reach target speed V1by time T2. In other words, the speed adjustment period is period TE1from time T1to time T2. Period TE1is set in this example to a range from 1 second to 10 seconds, but may be shorter or longer.

In the first speed condition, the speed adjustment period is equal to the time required to accelerate the first belt motor47b. The controller150drives the drive roller47ato accelerate at a default acceleration rate after starting the first belt motor47b, and stops acceleration when speed VA reaches target speed V1. The time required for this acceleration is the speed adjustment period.

As described above, when the drum41starts operating with defibrated material MB inside the drum41, the amount of first screened material MC falling from the drum41is temporarily greater than when defibrated material MB is not in the drum41. As a result, the amount of first screened material MC dropping to the mesh belt46after the first sieve motor40astarts turning is temporarily greater than the amount suitable for making a sheet S. As a result, as indicated by the (2) inFIG. 8, the thickness of the first web W1exceeds thickness TH1, and the peak thickness TH2is significantly greater than thickness TH1.

In the setup process shown inFIG. 7, the controller150sets one of the second to fifth speed conditions when defibrated material MB is already inside the drum41.

The second to fifth speed conditions each set the speed adjustment period longer than period TE1, and provide a period during the speed adjustment period in which speed VA reaches a speed greater than target speed V1. By reaching a speed VA greater than the target speed V1, the speed of the mesh belt46moving below the drum41increases, and the amount of first screened material MC per unit area of the mesh belt46decreases. As a result, the thickness of the first web W1accumulating on the mesh belt46decreases. Increasing the thickness of the first web W1can be suppressed by setting speed VA to a higher speed while the amount of first screened material MC falling from the drum41is high. The speed adjustment period in this case is the time until the speed VA reaches the target speed V1, and the speed VA during the speed adjustment period is greater than the target speed V1, but speed VA may be less than target speed V1temporarily.

In the second speed condition, defibrated material MB is in the drum41, the humidity detected by the first temperature/humidity detector323is greater than or equal to the reference value, and the fiber length is greater than or equal to the reference value. The second speed condition is a condition whereby the speed adjustment period is adjusted to a period longer than period TE1. In the second speed condition, speed VA is greater than target speed V1for at least part of the speed adjustment period. The second speed condition includes information specifying the maximum setting for the speed VA, and may include information specifying the length of the speed adjustment period. The second speed condition may also include information specifying the pattern of change in the speed VA during the speed adjustment period, thereby enabling changing speed VA during the speed adjustment period.

In the fourth speed condition, defibrated material MB is in the drum41, the humidity detected by the first temperature/humidity detector323is lower than to the reference value, and the fiber length is greater than or equal to the reference value. Because the humidity inside the drum41is lower than when the second speed condition is set, the amount of first screened material MC falling from the drum41increases temporarily. As a result, the fourth speed condition is a condition whereby the thickness of the first web W1accumulated on the mesh belt46becomes thinner than under the second speed condition. The fourth speed condition is an example of a condition setting the length of the speed adjustment period longer than in the second speed condition, and/or a condition in which the maximum speed VA is higher than in the second speed condition.

In the third speed condition, defibrated material MB is in the drum41, the humidity detected by the first temperature/humidity detector323is greater than or equal to the reference value, and the fiber length is shorter than the reference value. Because the fiber length is shorter than when the second speed condition is set, the amount of first screened material MC falling from the drum41increases temporarily. As a result, the third speed condition is a condition whereby the thickness of the first web W1accumulated on the mesh belt46becomes thinner than under the second speed condition. The third speed condition is an example of a condition setting the length of the speed adjustment period longer than in the second speed condition, and/or a condition in which the maximum speed VA is higher than in the second speed condition.

Note that the length of the speed adjustment period and/or the maximum speed VA may be the same or different in the third speed condition and the fourth speed condition.

The length of the speed adjustment period and the maximum speed VA may be determined with consideration for whether the effect of humidity inside the drum41on the amount of first screened material MC that drops from the drum41, or the effect of the length of fiber in the defibrated material MB on the amount of first screened material MC that drops from the drum41, is greater.

When the effect of humidity inside the drum41on the amount of first screened material MC that drops through is greater than the effect of the length of fiber in the defibrated material MB, the fourth speed condition is preferably configured so that the thickness of the first web W1is thinner than in the third speed condition. More specifically, the fourth speed condition is preferably configured so that the length of the speed adjustment period is greater than in the third speed condition, or the maximum speed VA is greater in the fourth speed condition than in the third speed condition, or both of these conditions are met.

However, if the effect of humidity inside the drum41on the amount of first screened material MC that drops through is less than the effect of the length of fiber in the defibrated material MB, the third speed condition is preferably configured so that the thickness of the first web W1is thinner than in the fourth speed condition. More specifically, the third speed condition is preferably configured so that the length of the speed adjustment period is greater than in the fourth speed condition, or the maximum speed VA is greater in the third speed condition than in the fourth speed condition, or both of these conditions are met.

The fifth speed condition is set when there is defibrated material MB inside the drum41, the humidity detected by the first temperature/humidity detector323is lower than the reference value, and the length of fiber is shorter than the reference value. Compared with the first to fourth speed conditions, the thickness of the first web W1is thinner when the fifth speed condition is set. More specifically, compared with the first to fourth speed conditions, the length of the speed adjustment period is longer, and/or the maximum speed VA is higher, in the fifth speed condition.

As described above, when the amount of first screened material MC dropping from the drum41to the mesh belt46may increase temporarily, the controller150sets the speed VA during the speed adjustment period greater than target speed V1when the first belt motor47bstarts operating. As a result, the controller150suppresses variation in the thickness of the first web W1, and in the process of the sheet manufacturing apparatus100making sheets S, the amount of first screened material MC supplied to processes downstream from the first web former45can be stabilized. Because variation in the quality of the sheets S can therefore be suppressed, the burden of making manual adjustments to suppress variation in the quality of the sheets S can also be reduced.

FIG. 9,FIG. 10, andFIG. 11are graphs showing examples of the operating speed VA of the mesh belt46and change in the thickness of the first web W1when the second to fifth speed conditions are set.

In these figures, (1) indicates speed VA detected by the first belt speed detector322, and (2) indicates the thickness of the first web W1detected by the first thickness detector324. The Y-axis, X-axis, target speed V1, thickness TH1and TH2, and time T1are the same as inFIG. 8. For comparison, these figures also show time T2fromFIG. 8.

FIG. 9shows an example in which the speed VA changes in steps, and more specifically an example in which speed VA changes in two steps. The controller150sets a period for holding an intermediate speed V2that is lower than the target speed V1before starting accelerating speed VA to target speed V1. More specifically, the controller150starts turning the first belt motor47bat time T1, and accelerates the first belt motor47bso that speed VA reaches intermediate speed V2at time T2. The controller150then holds speed VA at intermediate speed V2until time T3, then decelerates the first belt motor47bfrom time T3to time T4to reach target speed V1at time T4.

The speed adjustment period is indicated by reference numeral TE2in the example inFIG. 9. This speed adjustment period TE2is an example of a first period. The speed adjustment period TE2(time T1-T4) is longer than the period from time T1-T2. In addition, speed VA in the speed adjustment period TE2is greater than target speed V1. As a result, the controller150holds speed VA at a speed greater than target speed V1during the speed adjustment period TE2after the first belt motor47bstarts turning. As shown inFIG. 9(2), the detection value of the first thickness detector324varies from around time T2, but the peak thickness TH3of the first web W1is less than the peak thickness TH2shown inFIG. 8. It is thus obvious that variation in the thickness of the first web W1is suppressed.

FIG. 10shows an example in which the speed VB changes in steps, and more specifically an example in which speed VB changes in multiple steps. The controller150sets multiple periods for holding speed VA at intermediate speeds V3, V4and V5that are lower than the target speed V1during the speed adjustment period TE2(time T1to T10). More specifically, the controller150starts turning the first belt motor47bat time T1, and accelerates the first belt motor47bso that speed VA reaches intermediate speed V3at time T2. The controller150then holds speed VA at intermediate speed V3from time T2to time T5, and at time T5slows the first belt motor47bso that speed VA reaches intermediate speed V4at time T6. The controller150then holds speed VA at intermediate speed V4from time T6to time T7, and at time T7slows the first belt motor47bso that speed VA reaches intermediate speed V5at time T8. The controller150then holds speed VA at intermediate speed V3from time T8to time T9, and at time T9slows the first belt motor47bso that speed VA reaches intermediate speed V1at time T10.

In the example inFIG. 10, the speed adjustment period TE2is from time T1to time T10. This speed adjustment period TE2is longer than the period from time T1to time T2inFIG. 8. The controller150thus holds the speed VA above the target speed V1during the speed adjustment period TE2after the first belt motor47bstarts turning.

As shown by curve (2) inFIG. 10, the value detected by the first thickness detector324fluctuates from approximately time T11, but the peak thickness TH4of the first web W1is less than the peak thickness TH2shown inFIG. 8. More specifically, the peak thickness TH4is successfully suppressed by inserting a speed adjustment period TE2in which the speed is greater than the target speed V1immediately after the drum41starts turning when the amount of first screened material MC passing through the drum41increases easily.

As shown inFIG. 9andFIG. 10, the controller150can change the speed VA in steps, and the number of steps of change in the speed VA, and the intermediate speeds, can be varied. For example, speed VA may be changed in five or more steps.

The controller150may also be configured to not maintain the speed VA at a constant rate during the speed adjustment period TE2. In this case, the controller150may control a linear change in the speed VA. More specifically, the first belt motor47bmay be operated so that the rate of change in the speed VA maintains a constant rate of acceleration. The controller150may also control the first belt motor47bso that the acceleration rate of speed VA changes during the speed adjustment period TE2. Each of these configurations can be expected to suppress variation in the first web W1insofar as the period TE1is longer than from time T1to time T2, and speed VA is greater than the target speed V1during the speed adjustment period TE2.

FIG. 11shows an example of the controller150controlling the speed of the first belt motor47bbased on the detection value received from the first thickness detector324, that is, an example of feedback control. In this example, the length of the speed adjustment period TE2is set as an operating condition of the first belt motor47b. The operating conditions of the first belt motor47bmay also include the minimum speed VA during the speed adjustment period TE2.

In the example inFIG. 11, the controller150starts accelerating the first belt motor47b, and starts acquiring the detection value from the first thickness detector324, at time T1. The controller150increases or decreases the speed of the first belt motor47baccording to the difference between the detection value from the first thickness detector324and a threshold value. The threshold value related to the detection value of the first thickness detector324may be thickness TH1, or another value included in the reference data162.

In the example inFIG. 11, speed VA is greater than target speed V1for at least part of the speed adjustment period TE2. The controller150decelerates the first belt motor47bfrom time T11so that the speed VA goes to target speed V1at time T12according to the length of the speed adjustment period TE2defined by the speed conditions.

In the example inFIG. 11, the second to fifth speed conditions may contain little information, such as information indicating the length of the speed adjustment period TE2, which has the advantage of simplifying the process setting the second to fifth speed conditions.

The second to fifth speed conditions can use the examples shown inFIG. 9toFIG. 11. For example, all of the second to fifth speed conditions can use the two step acceleration pattern shown inFIG. 9. In this case, the second to fifth speed conditions may include information indicating the length of the speed adjustment period TE2, or information indicating the maximum and/or minimum speed VA in the speed adjustment period TE2. In addition, the second to fifth speed conditions may include patterns that change the speed VA as shown inFIG. 9.

The pattern of change in speed VA may also be the same in the second to fifth speed conditions. For example, the second to fifth speed conditions may be conditions that change speed VA by the different patterns shown inFIG. 9toFIG. 11.

Furthermore, in the examples inFIG. 9toFIG. 10, speed VA is held constant after reaching target speed V1, but speed VA does not need to remain constant at target speed V1throughout sheet S production. For example, speed VA may be varied according to the sheet S manufacturing conditions and the operating conditions of the sheet manufacturing apparatus100.

As described above, a sheet manufacturing apparatus100according to the first embodiment of the invention has a drum41that sieves first screened material MC, which is material containing fiber, and a first web former45that accumulates first screened material MC discharged from the drum41. The sheet manufacturing apparatus100also has the parts of a sheet maker102that processes the first web W1, that is, the first screened material MC, accumulated in the first web former45.

During processing by the processor, the sheet manufacturing apparatus100operates the mesh belt46of the first web former45at a target speed V1. When starting from a state in which the drum41is stopped (not turning), a startup operation including a state in which the mesh belt46operates at a faster speed than the target speed V1during the speed adjustment period TE2is executed. The processor may include any of the processes executed after the first web former45, and may be selected from among any of the parts of the sheet maker102, for example.

In a sheet manufacturing apparatus100applying the fiber processing device and control method of a fiber processing device according to the invention, the speed VA at which the mesh belt46operates during the speed adjustment period TE2is greater than the target speed V1. As a result, even if the amount of first screened material MC discharged from the drum41increases briefly, an increase in the thickness of the first web W1accumulated in the first web former45can be suppressed.

The sheet manufacturing apparatus100also maintains a state in which the first web former45operates at a greater speed than the target speed V1during the speed adjustment period TE2. For example, a period in which speed VA is greater than target speed V1is maintained in the examples shown inFIG. 9toFIG. 11. Holding speed VA greater than target speed V1when the amount of first screened material MC dropping from the drum41may easily increase can be expected to effectively suppress variation in the thickness of the first web W1due to temporary variations in the amount of first screened material MC.

The first web former45also has a mesh belt46that an accumulate the first screened material MC in a sheet, and the mesh belt46moves in a circulating path defined by the tension rollers47. Therefore, by setting the speed VA at which the mesh belt46moves faster than the target speed V1, variation in the thickness of the first web W1accumulated on the mesh belt46can be suppressed.

During processing by the processor, the sheet manufacturing apparatus100drives the mesh belt46at a target speed V1, and in the speed adjustment period TE2, maintains the operating speed of the mesh belt46at a second speed that is faster than the target speed V1. This configuration can effectively suppress variation in the thickness of the first web W1due to temporary variation in the amount of first screened material MC in the speed adjustment period TE2because the mesh belt46operates at a higher speed than the target speed V1for the speed VA when making sheets S.

When the sheet manufacturing apparatus100starts from a state in which the drum41is stopped, the operating speed of the mesh belt46may accelerate to a higher speed than the target speed V1before the drum41starts turning. In this case, during a second period after acceleration ends, the first belt motor47bcontinues driving the mesh belt46at a faster speed than target speed V1. Because the speed VA exceeds the target speed V1during the time when the amount of first screened material MC dropping from the drum41increases easily, this configuration can effectively suppress variation in the thickness of the first web W1due to temporary variations in the amount of first screened material MC.

When starting from a state in which the drum41is stopped, the sheet manufacturing apparatus100executes a startup operation when there is defibrated material MB inside the drum41. Because speed VA thus exceeds the target speed V1during the time when the amount of first screened material MC dropping from the drum41increases easily, this configuration can effectively suppress variation in the thickness of the first web W1due to temporary variations in the amount of first screened material MC. By executing the normal startup sequence when the amount of first screened material MC dropping from the drum41does not vary easily, a drop in productivity manufacturing sheets S can be prevented.

The drum41is a round cylinder having openings formed in the outside surface of the drum41, and configured to rotate on the axis of the cylinder. When the drum41starts turning with defibrated material MB inside the drum41, the amount of first screened material MC that drops onto the mesh belt46when operation starts can fluctuate easily. Variation in the thickness of the first web W1due to variation in the amount of first screened material MC can be suppressed in this configuration because a period in which the mesh belt46moves at a speed greater than the target speed V1is maintained by the controller150.

A sheet manufacturing apparatus100applying the fibrous feedstock recycling device of the invention has a defibrator20as a refiner that refines feedstock material MA containing fiber. The sheet manufacturing apparatus100also has a drum41that sieves the defibrated material MB refined by the refiner, and a first web former45as an accumulator that accumulates first screened material MC discharged from the drum41. The sheet manufacturing apparatus100also has the parts of the sheet maker102as a processor that processes the first screened material MC accumulated on the first web former45. While the sheet manufacturing apparatus100is making sheets S, the first web former45operates at a target speed V1. When the sheet manufacturing apparatus100starts from when the drum41is at a stop, a startup operation including a state in which the first web former45operates at a faster speed than the target speed V1during the speed adjustment period TE2after the drum41starts executes. As a result, an increase in the thickness of the first web W1accumulated in the first web former45when the amount of first screened material MC moving from the drum41easily varies can be suppressed.

A second embodiment of the invention is described below.

The second embodiment describes an operation suppressing variation in the thickness of the first web W1by the drive controller152controlling the speed VA of the mesh belt46and the speed VB of the drum41in the startup operation. The configuration of the sheet manufacturing apparatus100according to the second embodiment of the invention is the same as in the first embodiment, further description of the configuration of the sheet manufacturing apparatus100is omitted in the drawings and below.

In this second embodiment, the controller150executes the same operation shown inFIG. 6as the first embodiment. In step ST7, the controller150controls the first belt motor47band first sieve motor40aaccording to the operating conditions set in step ST1.

FIG. 12is a flow chart of the setup process executed in step ST1inFIG. 6.

The setup process in the second embodiment also sets operating conditions related to controlling the first sieve motor40a. The operating conditions set in the second embodiment include information relating to operation of the first belt motor47b, and information relating to operation of the first sieve motor40a. In the first embodiment, the first to fifth speed conditions include information related to the length of the speed adjustment period TE2, and information related to the maximum or minimum speed VA. The first to fifth speed conditions in the second embodiment include information related to the length of the acceleration time TE3until speed VB reaches target speed V1used when making sheets S.

In the setup process ofFIG. 12, the controller150determines if there is defibrated material MB in the drum41(step ST31).

If there is no defibrated material MB inside the drum41(step ST31: NO), the controller150sets a first speed condition as the condition for accelerating the speed of the first sieve motor40aand first belt motor47b(step ST32), and ends the setup process.

If there is defibrated material MB in the drum41(step ST31: YES), the controller150determines whether or not the humidity detected by the first temperature/humidity detector323is greater than or equal to the reference value contained in the reference data162(step ST33). If the humidity is greater than or equal to the reference value (step ST33: YES), the controller150determines if the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data162(step ST34).

If the length of fiber is greater than or equal to the reference value (step ST34: YES), the controller150sets a second speed condition as the condition for accelerating the speed of the first sieve motor40aand first belt motor47b(step ST35), and ends the setup process.

If the length of fiber is shorter than the reference value (step ST34: NO), the controller150sets a third speed condition as the condition for accelerating the speed of the first sieve motor40aand first belt motor47b(step ST36), and ends the setup process.

However, if the humidity is less than the reference value (step ST33: NO), the controller150determines if the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data162(step ST37).

If the length of fiber is greater than or equal to the reference value (step ST37: YES), the controller150sets a fourth speed condition as the condition for accelerating the speed of the first sieve motor40aand first belt motor47b(step ST38), and ends the setup process.

If the length of fiber is shorter than the reference value (step ST37: NO), the controller150sets a fifth speed condition as the condition for accelerating the speed of the first sieve motor40aand first belt motor47b(step ST39), and ends the setup process.

FIG. 13is a graph showing the change in the speed VB of the drum41and the thickness of the first web W1, and shows an example of the operation when the second to fifth speed conditions are set in the setup process ofFIG. 12. InFIG. 13andFIG. 14, The Y-axis, X-axis, target speed V1, thickness TH1and TH2, and time T1are the same as inFIG. 8.

InFIG. 13, curve (1) indicates the speed VB detected by the first sieve speed detector321, and (2) indicates the thickness of the first web W1. As described above, speed V11is the speed VB when making sheets S, and in the startup operation, the controller150accelerates the first sieve motor40auntil the speed VB of the drum41reaches speed V11. Time T1when acceleration of the first sieve motor40aand first belt motor47bstarts is the same as inFIG. 8and described above.

The time from when the controller150starts the first sieve motor40ato when speed VB reaches speed V11is period TE3.FIG. 13shows an example of changing speed VB in steps, and more specifically is an example of changing speed VB in two steps. In period TE3, the controller150provides a period in which speed VB is held at an intermediate speed V12that is below speed V11. More specifically, the controller150starts turning the first sieve motor40aat time T1, and accelerates the first sieve motor40aso that speed VB reaches intermediate speed V12at time T21. The controller150then holds speed VB at intermediate speed V12from time T21to time T22, then accelerates the first sieve motor40aagain from time T22to reach target speed V1at time T23.

In the example inFIG. 13, the time T23at which speed VB reaches target speed V11is after time T2described above. In other words, the controller150holds speed VB at a speed less than target speed V11for period TE3(from time T1to time T23) after the first sieve motor40astarts turning. As shown by (2) inFIG. 13, the value detected by the first thickness detector324fluctuates from approximately time T21, but the peak thickness TH11of the first web W1is less than the peak thickness TH2shown inFIG. 8. This demonstrates that variation in the thickness of the first web W1is suppressed.

The second to fifth speed conditions include information specifying the length of the acceleration time TE3, time T23, and speed VB in period TE3(intermediate speed V12, for example), for controlling the first sieve motor40a.

The controller150also executes the startup operation of the first belt motor47baccording to the second to fifth speed conditions. More specifically, the startup operation in the second embodiment includes controlling speed VA and controlling speed VB.

FIG. 14is a graph showing an example of change in the speed VA of the mesh belt46and the thickness of the first web W1, and shows an example of when second to fifth speed conditions are set. InFIG. 14, line (1) indicates the speed VA detected by the first belt speed detector322, and (2) indicates the thickness of the first web W1detected by the first thickness detector324.

InFIG. 14, the controller150controls the speed of the first belt motor47bbased on the detection value from the first thickness detector324, that is, is an example of feedback control. In this example, the length of the speed adjustment period TE2is set as an operating condition of the first belt motor47b. The operating conditions of the first belt motor47bmay also include the minimum speed VA during the speed adjustment period TE2.

In the example inFIG. 14, the controller150starts accelerating the first belt motor47b, and starts acquiring the detection value from the first thickness detector324, at time T1. The controller150increases or decreases the speed of the first belt motor47baccording to the difference between the detection value from the first thickness detector324and a threshold value. The threshold value related to the detection value of the first thickness detector324may be thickness TH1, or another value included in the reference data162.

In the example inFIG. 14, speed VA is greater than target speed V1for at least part of the speed adjustment period TE2(time T1to time T25). The controller150decelerates the first belt motor47bfrom time T11so that the speed VA goes to target speed V1at time T25according to the length of the speed adjustment period TE2defined by the speed conditions.

In the example inFIG. 14, the second to fifth speed conditions may contain little information, such as information indicating the length of the speed adjustment period TE2, which has the advantage of simplifying the process setting the second to fifth speed conditions.

The second to fifth speed conditions are not limited to the example shown inFIG. 14, and the examples shown inFIG. 9andFIG. 10can be used.

During processing by the processor, the sheet manufacturing apparatus100according to the second embodiment of the invention drives the drum41at a speed V11to discharge material from the drum41. When the sheet manufacturing apparatus100starts from a state in which the drum41is stopped, a sieve startup operation including a state in which the drum41operates at a different speed than the third speed during the speed adjustment period TE2is executed. The sieve startup operation is an operation of controlling the speed of the drum41according to the speed conditions set in the setup process (FIG. 12) as shown inFIG. 13, for example.

By controlling both speed VA and speed VB, this configuration can adjust the amount of first screened material MC discharged from the drum41, and the speed of the mesh belt46, in the period when the amount of first screened material MC discharged from the drum41increases easily. As a result, variation in the thickness of the first web W1can be more effectively suppressed.

A third embodiment of the invention is described next.

The first and second embodiments describe adjusting the speed VA of the mesh belt46and/or the speed VB of the drum41in the startup operation by the drive controller152controlling the first belt motor47band/or first sieve motor40a.

In the third embodiment, the drive controller152adjusts the speed VD of the drum61by controlling the second belt motor74band/or second sieve motor60ain the startup operation.

More specifically, the controller150applies the control of the first belt motor47bdescribed in the first embodiment to controlling the second belt motor74b. The controller150also applies control of the first sieve motor40aand first belt motor47bdescribed in the second embodiment to controlling the second sieve motor60aand second belt motor74b.

In the third embodiment, the drum61is an example of a sieve, the second sieve motor60ais an example of a sieve driver, the second web former70is an example of an accumulator, and the mesh belt72is an example of a receiver. The second belt motor74bis also an example of a driver, and the second temperature/humidity detector333is an example of a humidity detector.

3-1. Second Web Forming Conditions

The conditions for forming the second web W2formed by the second web former70are described below with reference toFIG. 3.

The thickness of the second web W2is determined by the amount of mixture MX, which is the material supplied to the mesh belt72, and the amount of movement of the mesh belt72per unit time. The amount of movement of the mesh belt72per unit time is speed VC.

One factor determining the amount of mixture MX supplied to the mesh belt72, that is, the amount of mixture MX passing through the openings61a, is speed VD. As speed VD increases, the mixture MX is more quickly detangled in the drum61, and the mixture MX passes more easily through the openings61a. In addition, the greater the speed VD, the more easily the mixture MX passes the openings61a. Therefore, the amount of mixture MX passing the openings61aincreases as the speed VD increases.

The amount of mixture MX passing the openings61achanges when the drum61starts operating from a stop. Because rotation of the drum61produces friction between the fibers of the mixture MX inside the drum61, the mixture MX also becomes charged. If the mixture MX clumps due to this static electricity, it becomes more difficult for the mixture MX to pass the openings61a. On the other hand, when the drum61is stopped, the charge of the charged mixture MX is discharged, and clumps of fiber in the mixture MX break apart. Therefore, when the drum61starts turning from a stop, that is, when the drum61starts operating, that is, during startup, the amount of mixture MX passing the openings61atemporarily increases.

The amount of mixture MX passing the openings61ais also affected by the humidity in the drum61. Humidity as used here can be referred to as relative humidity (RH). If the humidity inside the drum61is low, the mixture MX becomes charged and fibers clump easily. Therefore, the lower the humidity inside the drum61, and the drum61starts turning from a stop, that is, during startup, the amount of mixture MX passing the holes61atemporarily increases.

The amount of mixture MX passing the openings61aalso varies according to the length of the fiber in the mixture MX. Short fibers pass through the openings61aeasily. Therefore, the shorter the fibers in the mixture MX, the greater the amount of mixture MX that passes the openings61a.

In other words, the greatest factor determining the amount of mixture MX supplied from the drum61to the mesh belt72is the speed VD of the drum61. Factors that change the amount of mixture MX include whether or not the drum61is starting up, the humidity inside the drum61, and the length of fiber in the mixture MX.

If the thickness of the second web W2varies, the amount of material supplied to processes downstream from the second web former70may vary, affecting the quality of the sheets S manufactured by the sheet manufacturing apparatus100.

The controller150of the sheet manufacturing apparatus100therefore executes a control process that suppresses variation in the thickness of the second web W2.

To execute control related to the thickness of the second web W2, the controller110can acquire the detection value output from the second thickness detector334. As shown inFIG. 4, the controller110can also control the speed of the second sieve motor60aand second belt motor74b.

3-2. Sheet Manufacturing Apparatus Operation

The controller150first executes the operation shown inFIG. 6by drive controller152. In the setup process of step ST1, the controller150configures settings related to the operation of the second belt motor74b. In this case, in the setup process shown inFIG. 7, the controller150sets the speed VC of the mesh belt72according to the first to fifth speed conditions. The first embodiment applied the first to fifth speed conditions to speed VA, but the first to fifth speed conditions can also be applied to speed VC.

In the setup process of step ST1, the controller150also configures settings related to the operation of the second sieve motor60aand second belt motor74b. In this case, the controller150sets the first to fifth speed conditions for speed VD of the drum61and speed VC of the mesh belt72in the setup process inFIG. 12.

The controller150applies the setup processes inFIG. 7andFIG. 12to speed VC, or to speed VC and speed VD. The first to fifth speed conditions are basic conditions for increasing speed VD from zero when the drum61starts operating, and include a target speed for the second sieve motor60a, and the time or the acceleration rate of the second sieve motor60ato the target speed.

Control related to starting speed VC may use the patterns shown inFIG. 9toFIG. 11andFIG. 14. More specifically, the data shown in these figures may be used as the data related to setting speed VC by substituting speed VA indicated by the line (1) for speed VC based on the detection values from the second belt speed detector332. In addition, the data shown inFIG. 13may be used as data related to the speed of speed VD by substituting speed VB for speed VD based on the detection value from the second sieve speed detector331.

The target speed V1of speed VC may be the same as target speed V1of speed VA, or different.

The speed adjustment period in the second to fifth speed conditions may be understood as the speed adjustment period related to speed VC. This also applies to the acceleration time of speed VB. The relationship between the length of the speed adjustment period in each of the speed conditions, and the maximum speed VC in the speed adjustment period, are also as described in the first and second embodiments.

The first to fifth speed conditions related to speed VC may be the same as the first to fifth speed conditions described in the first embodiment, or first to fifth speed conditions optimized for the operation of the drum61may be used. This also applies to the first to fifth speed conditions set for speed VD.

In the third embodiment, the controller150suppresses variation in the thickness of the second web W2by controlling the speed VC of the mesh belt72when the amount of mixture MX dropping from the drum61to the mesh belt72increases temporarily. As a result, in the sheet S manufacturing process of the sheet manufacturing apparatus100, the amount of mixture MX supplied to processes downstream from the second web former70can be stabilized, and variation in the quality of the sheet S can be suppressed. The burden of making manual adjustments to suppress variation in the quality of the sheet S can also be reduced.

A sheet manufacturing apparatus100applying the fiber processing device and control method of a fiber processing device according to the third embodiment of the invention has a drum61that sieves mixture MX, which is material containing fiber, and a second web former70for accumulating mixture MX discharged from the drum61. The sheet manufacturing apparatus100also has the parts of a processor that processes the second web W2accumulated on the mesh belt72, that is, the mixture MX. The processor may include any process downstream from the second web former70, such as the sheet former80or sheet cutter90.

During processing by the processor, the sheet manufacturing apparatus100operates the mesh belt72at a target speed V1. When starting with the61stopped, the sheet manufacturing apparatus100executes a startup operation including a state in which the mesh belt72travels faster than the target speed V1during a speed adjustment period after the drum61starts. As a result, even if the amount of mixture MX discharged from the drum61increases temporarily, an increase in the thickness of the second web W2accumulated on the second web former70can be suppressed. The amount of mixture MX supplied to processes downstream from the second web former70while the sheet manufacturing apparatus100manufactures sheets S can be stabilized. For example, variation in the quality of the sheet S can be suppressed, and the burden of making manual adjustments to stabilize the quality of the sheet S can also be reduced.

During the speed adjustment period, the sheet manufacturing apparatus100also maintains a state in which the mesh belt72operates at a higher speed than the target speed V1. As a result, because speed VC is held at a speed faster than the target speed V1during the period when the amount of mixture MX falling from the drum61increases easily, variation in the thickness of the second web W2due to variation in the amount of mixture MX can be effectively suppressed.

The second web former70has a mesh belt72on which the mixture MX can be accumulated in a sheet, and the mesh belt72moves in a circulating path defined by the tension rollers74. Therefore, by setting the speed VC at which the mesh belt72moves faster than the target speed V1, variation in the thickness of the second web W2accumulated on the mesh belt72can be suppressed.

During processing by the processor, the sheet manufacturing apparatus100drives the mesh belt72at a target speed V1, and in the speed adjustment period, maintains the operating speed of the mesh belt72at a second speed that is faster than the target speed V1. This configuration can effectively suppress variation in the thickness of the second web W2due to temporary variation in the amount of mixture MX in the speed adjustment period because the mesh belt72operates at a higher speed than the target speed V1for the speed VC when making sheets S.

When the sheet manufacturing apparatus100starts from a state in which the drum61is stopped, the operating speed of the mesh belt72may accelerate to a higher speed than the target speed V1, and in a second period after acceleration ends, the mesh belt72is held at an operating speed greater than the target speed V1. Because the speed VC exceeds the target speed V1during the time when the amount of mixture MX dropping from the drum61increases easily, this configuration can effectively suppress variation in the thickness of the second web W2due to variations in the amount of mixture MX.

When starting from a state in which the drum61is stopped, the sheet manufacturing apparatus100may execute the startup operation when there is mixture MX inside the drum61. Because speed VC thus exceeds the target speed V1during the time when the amount of mixture MX dropping from the drum61increases easily, this configuration can effectively suppress variation in the thickness of the second web W2due to variation in the amount of mixture MX. By executing the normal startup sequence when the amount of mixture MX dropping from the drum61does not vary easily, a drop in productivity manufacturing sheets S can be prevented.

The drum61is a round cylinder having openings formed in the outside surface of the drum61, and configured to rotate on the axis of the cylinder. When the drum61starts turning with m×m inside the drum61, the amount of mixture MX that drops onto the mesh belt72when operation starts can fluctuate easily. Variation in the thickness of the second web W2due to variation in the amount of mixture MX can be suppressed in this configuration because a period in which the mesh belt72moves at a speed greater than the target speed V1is maintained by the controller150.

Control of the first sieve motor40aas described in the second embodiment can also be applied to controlling the second sieve motor60a. More specifically, control of the speed of the drum41can be applied to controlling the speed of drum61. When the sheet manufacturing apparatus100starts from a state in which the drum61is stopped, a sieve startup operation including a state in the speed adjustment period in which the drum61operates at a different speed than the speed V11during sheet S production is executed. In this case, by controlling both speed VC and speed VD, the amount of mixture MX discharged to the mesh belt72, and the speed of the mesh belt72, can be adjusted in the period in which the amount of mixture MX falling from the drum61may increase easily. As a result, variation in the thickness of the second web W2can be more effectively suppressed.

4. Other Embodiments

The embodiments described above are only examples of specific embodiments of the invention as described in the accompanying claims, do not limit the invention, and can be varied in many ways as described below without departing from the scope and spirit of the invention as described in the accompanying claims.

The foregoing first embodiment describes the controller150applying the setup process inFIG. 7to controlling the speed of the mesh belt46, and starting the mesh belt46and drum41in step ST7based on the speed conditions that are set.

The foregoing second embodiment describes the controller150executing the setup process shown inFIG. 12, and starting the mesh belt46and drum41in step ST7based on the speed conditions that are set.

The foregoing third embodiment describes the controller150executing the setup processes inFIG. 7andFIG. 12to control the speed of the mesh belt72, or control the speed of the mesh belt72and the drum61.

The invention is not so limited, however, and the controller150may execute the setup process inFIG. 7to control the speed of both mesh belt46and mesh belt72. The controller150may also execute the setup process ofFIG. 12on each of drums41,61and mesh belts46,72. In other words, the controller150may apply the control method of the invention to the speed VA of the mesh belt46, the speed VB of the drum41, the speed VC of mesh belt72, and speed VD of drum61. In this case, the controller150also controls the first sieve motor40a, second sieve motor60a, first belt motor47b, and second belt motor74b.

The foregoing embodiments describe the mesh belt46and the mesh belt72as foraminous mesh belts functioning as accumulators. However, the invention is not so limited, and belts without openings, or flat panels, may be used as the accumulator.

The sieves are also not limited to drum-shaped drums41,61. For example, a cylindrical sieve with openings may be used as the sieve.

The location of the first temperature/humidity detector323in the foregoing embodiments is also not limited to inside the drum41, and may be inside the housing43, for example. Likewise, the second temperature/humidity detector333is not limited to being disposed inside the drum61, and may be located inside the housing63.

A temperature sensor or a sensor for detecting the moisture content of the feedstock material MA may be disposed to the feedstock feeder10, in which case the controller150can estimate the humidity inside the drum41and inside the drum61based on the detected temperature and/or moisture content of the feedstock material MA. A temperature/humidity sensor may also be disposed in conduit2and conduit3, and configured to detect the temperature and/or humidity before and after the defibrator20. In this case, the controller150can estimate the humidity inside the drum41and inside the drum61based on the change in the detected temperature and/or moisture content before and after processing by the defibrator20. A temperature/humidity sensor may also be disposed to detect the temperature and/or humidity inside the housing of the sheet manufacturing apparatus100. □

When the invention is applied to the air-laying device60and second web former70in the third embodiment, a classifier that selects and separates the defibrated material MB into first screened material MC, second screened material, and third screened material D may be provided instead of classifier40. This classifier may be a cyclone classifier, elbow-jet classifier, or eddy classifier, for example.

The specific configurations whereby the drive controller152controls the speed of the first sieve motor40a, second sieve motor second sieve motor60a, first belt motor47b, and second belt motor74bare also not specifically limited, and, for example, may be configured to vary the voltage of the drive current supplied to the motors, or control the speed by other methods.

The sheet manufacturing apparatus100is also not limited to manufacturing sheets S, and may be configured to make rigid sheets or paperboard comprising laminated sheets, or other web products. The manufactured product is also not limited to paper, and may be nonwoven cloth. The properties of the sheets S are also not specifically limited, and may be paper products that can be used as recording, writing, or printing on (such as copier paper, plain paper); wall paper, packaging paper, color paper, drawing paper, or bristol paper. When the sheet S is nonwoven cloth, it may be common nonwoven cloth, fiber board, tissue paper, kitchen paper, vacuum filter bags, filters, liquid absorption materials, sound absorption materials, cushioning materials, or mats.

The foregoing embodiments describe a sheet manufacturing apparatus100that acquires material by defibrating feedstock in air, and makes sheets S using this material and resin, as an example of a fiber processing device and fibrous feedstock recycling device according to the invention. However, application of the invention is not limited to such a device, however, and can be applied to a wet process sheet manufacturing apparatus that creates a solution or slurry of feedstock containing fiber in water or other solvent, and processes the feedstock into sheets. The invention can also be applied to an electrostatic sheet manufacturing apparatus that causes material containing fiber defibrated in air to adhere to the surface of a drum by static electricity, for example, and then processes the feedstock adhering to the drum into sheets.□