Patent Publication Number: US-11390992-B2

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

Description:
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. 
     Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates the configuration of a sheet manufacturing apparatus. 
         FIG. 2  illustrates the basic configuration of a classifier and first web former. 
         FIG. 3  illustrates the basic configuration of an accumulator and second web former. 
         FIG. 4  is a block diagram of the control system of the sheet manufacturing apparatus. 
         FIG. 5  is a function block diagram of the controller. 
         FIG. 6  is a flow chart of sheet manufacturing apparatus operation. 
         FIG. 7  is a flow chart of sheet manufacturing apparatus operation. 
         FIG. 8  is a graph showing an example of the relationship between the operating speed of the mesh belt and change in the thickness of the first web. 
         FIG. 9  is a graph showing an example of the relationship between the operating speed of the mesh belt and change in the thickness of the first web. 
         FIG. 10  is a graph showing an example of the relationship between the operating speed of the mesh belt and change in the thickness of the first web. 
         FIG. 11  is a graph showing an example of the relationship between the operating speed of the mesh belt and change in the thickness of the first web. 
         FIG. 12  is a flow chart of the operation of a sheet manufacturing apparatus according to the second embodiment of the invention. 
         FIG. 13  is a graph showing an example of the relationship between the operating speed of the drum unit and change in the thickness of the first web. 
         FIG. 14  is a graph showing an example of the relationship between the operating speed of the mesh belt and change in the thickness of the first web. 
     
    
    
     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. Embodiment 1 
     1. General Configuration of a Sheet Manufacturing Apparatus 
       FIG. 1  schematically illustrates the configuration of a sheet manufacturing apparatus  100  according to the invention. 
     The sheet manufacturing apparatus  100  executes a recycling process of extracting fiber from a feedstock material MA containing fiber and making new sheets S from the fiber. The sheet manufacturing apparatus  100  can 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 apparatus  100  can 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 apparatus  100  is an example of a fibrous feedstock recycling device and a fiber processing device according to the invention. 
     The sheet manufacturing apparatus  100  includes a feedstock feeder  10 , shredder  12 , defibrator  20 , classifier  40 , first web former  45 , rotor  49 , mixing device  50 , air-laying device  60 , second web former  70 , conveyor  79 , sheet former  80 , and sheet cutter  90 . The shredder  12 , defibrator  20 , classifier  40 , and first web former  45  configure a defibration processor  101  that defibrates the feedstock material MA and acquires material used to make the sheets S. The rotor  49 , mixing device  50 , air-laying device  60 , second web former  70 , sheet former  80 , and sheet cutter  90  configure a sheet maker  102  that processes the material acquired by the defibration processor  101  and makes sheets S. 
     The feedstock feeder  10  in this example is an automatic sheet feeder that holds and continuously supplies the feedstock material MA to the shredder  12 . The feedstock material MA may be an material containing fiber, such as recovered paper, waste paper, and pulp sheets. 
     The shredder  12  has shredder blades  14  that cut the feedstock material MA supplied by the feedstock feeder  10 , shreds the feedstock material MA in air by the shredder blades  14 , 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 shredder  12 . The feedstock material MA shredded by the shredder  12  is then collected in a hopper  9 , and conveyed through a conduit  2  to the defibrator  20 . 
     The defibrator  20  defibrates the coarse shreds produced by the shredder  12 . 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 defibrator  20  defibrating 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 defibrator  20  is 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 defibrator  20  is an example of a refiner. The defibrated material MB described below is an example of refined material. 
     The defibrator  20  defibrates 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 defibrator  20  uses a defibrator such as an impeller mill in this example. More specifically, the defibrator  20  has 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 shredder  12  to the defibrator  20 . This air current may be generated by the defibrator  20 , or the air current may be produced by a blower (not shown in the figure) disposed upstream or downstream from the defibrator  20  in the conveyance direction of the shreds and defibrated material. The defibrated material is carried by the air current from the defibrator  20  through a conduit  3  to the classifier  40 . The air current conveying the defibrated material to the classifier  40  may be generated by the defibrator  20  or the air current from the blower described above may be used. 
     The classifier  40  separates the components of the defibrated material defibrated by the defibrator  20  by the size of the fiber. The size of the fiber primarily indicates the length of the fiber. The classifier  40  has an inlet  42  through which defibrated material is introduced to the drum  41 , and an exit  44  from which second screened material described below is discharged from the drum  41 . The exit  44  connects to the defibrator  20  through a conduit  8 , and the classifier  40  returns the second screened material through the conduit  8  to the defibrator  20 . 
     The first web former  45  forms a first web W 1  by forming the material separated by the classifier  40  into a web. 
       FIG. 2  shows the basic configuration of the classifier  40  and first web former  45 , and shows the main parts thereof from the side. 
     As shown in  FIG. 1  and  FIG. 2 , the classifier  40  includes a drum  41 , and a housing  43  around the drum  41 . 
     The drum  41  in this example is configured with a sieve. More specifically, the drum  41  has mesh, a filter or a screen with openings that functions as a sieve. More specifically, the drum  41  is cylindrical, and is rotationally driven centered on the axis of the cylinder by a first sieve motor  40   a  (driver, sieve driver). At least part of the circumferential surface of the drum  41  is mesh. The mesh of the drum  41  may be a metal screen, expanded metal made by expanding a metal sheet with slits formed therein, or punched metal, for example. In  FIG. 2 , reference numeral  41   a  indicates the openings in the drum  41 . The operating speed at which the drum  41  operates by driving the first sieve motor  40   a  is speed VB. This speed VB is also referred to as the rotational speed of the drum  41 . Note that the direction of rotation of the drum  41  is not limited to the direction shown in  FIG. 2 , and the drum  41  may be driven in reverse, or driven bidirectionally by the first sieve motor  40   a  alternating the direction of rotation. In addition, speed VB is not limited to the speed in the direction indicated by the arrow in  FIG. 2 , and may indicate the speed of the drum  41  relative to when the drum  41  is not turning. 
     The drum  41  is an example of a sieve according to the invention. The defibrated material MB that is fed into the drum  41 , and the first screened material MC that is sieved through the openings  41   a , are examples of material. 
     The first web former  45  includes a mesh belt  46 , tension rollers  47 , and a suction device  48 . The mesh belt  46  is an endless metal belt, and is mounted around multiple tension rollers  47 . The mesh belt  46  circulates in a path configured by the tension rollers  47 . Part of the path of the mesh belt  46  is flat in the area below the drum  41 , and the mesh belt  46  forms a flat surface. 
     One of the tension rollers  47  is a drive roller  47   a  that drives the mesh belt  46 . The drive roller  47   a  turns as driven by a first belt motor  47   b , and drives the mesh belt  46  in the direction indicated by the arrow in the figure. The operating speed at which the mesh belt  46  operates by the drive power of the first belt motor  47   b  is speed VA. This speed VA is also referred to as the conveyance speed of the mesh belt  46 . 
     A servo motor, stepper motor, or other known type of motor may be used for the first sieve motor  40   a  and first belt motor  47   b . Gears, links, or other transfer mechanisms that transfer power may also be disposed between the first sieve motor  40   a  and drum  41 , and between the drive roller  47   a  and first belt motor  47   b.    
     The defibrated material MB introduced from the inlet  42  to the inside of the drum  41  is separated by rotation of the drum  41  into screened material that past through the openings  41   a  of the drum  41 , and remnants that do not pass through the openings  41   a . The screened material that past through the openings  41   a  includes fiber or particles that are smaller than the openings  41   a , 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 openings  41   a , and are referred to as second screened material below. The first screened material MC descends inside the housing  43  and falls onto the first web former  45 . As described above, the second screened material is conveyed from the exit  44  through conduit  8  to the defibrator  20 . 
     By rotation of the drum  41 , the first screened material MC that passes through the openings  41   a  descends inside the housing  43  to the mesh belt  46 . Numerous openings are also formed in the mesh belt  46 . Of the first screened material MC that descends from the drum  41 , components that are larger than the openings in the mesh belt  46  accumulate on the mesh belt  46 . Components of the first screened material MC that are smaller than the openings in the mesh belt  46  pass through the openings. The components that pass through the openings in the mesh belt  46  are 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 belt  46 , as well as resin particles, and particles of ink, toner, bleeding inhibitors and other material that is separated from the fibers by the defibrator  20 . The first web former  45  in this example is an example of an accumulator according to the invention, and the mesh belt  46  is an example of a receiver in the invention. The first sieve motor  40   a  is an example of a sieve driver, and the first belt motor  47   b is an example of a driver.    
     The suction device  48  pulls air from below the mesh belt  46 . The suction device  48  is connected through a conduit  23  to a first dust collector  27 . The first dust collector  27  has a filter for separating the third screened material D from the air current. Downstream from the first dust collector  27  is a first collection blower  28 , and the first collection blower  28  suctions air from the first dust collector  27 . 
     This configuration suctions small third screened material D from the first screened material MC that descended to the mesh belt  46  by the suction of the first collection blower  28 , and collects the third screened material D by the filter of the first dust collector  27 . The air that passes through the filter of the first dust collector  27  is discharged from a conduit  29 . 
     Because the air current suctioned by the suction device  48  pulls the first screened material MC descending from the drum  41  to the mesh belt  46 , the air current has the effect of promoting accumulation of the first screened material MC. The first screened material MC accumulated on the mesh belt  46  accumulates in a web, forming a first web W 1 . 
     Of the components of the first screened material MC, the first web W 1  comprises mainly fibers that are larger than the openings in the mesh belt  46 , and is a fluffy web containing much air. The first web W 1  is conveyed by movement of the mesh belt  46  to the rotor  49 . 
     Referring again to  FIG. 1 , the rotor  49  has a base  49   a  connected to a driver such as a motor (not shown in the figure), and fins  49   b  protruding from the base  49   a , and when the base  49   a  turns indirection of rotation R indicated by the arrow, the fins  49   b  rotate around the base  49   a . The fins  49   b  in this example are flat blades. In the example in  FIG. 1 , there are four fins  49   b  disposed equidistantly around the base  49   a.    
     The rotor  49  is disposed at the end of the flat part of the path of the mesh belt  46 . Because the path of the mesh belt  46  curves down at this end, the mesh belt  46  also curves and moves down. As a result, the first web W 1  conveyed by the mesh belt  46  extends forward from the mesh belt  46  and contacts the rotor  49 . The first web W 1  is then broken up by the fins  49   b  striking the first web W 1 , and reduced to small clumps of fiber. These clumps then travel through the conduit  7  located below the rotor  49 , and are conveyed to the mixing device  50 . Because the first web W 1  is a soft, fluffy structure of fiber accumulated on the mesh belt  46  as described above, the first web W 1  is easily broken up by collision with the rotor  49 . 
     The rotor  49  is positioned so that the fins  49   b  can contact the first web W 1  but the fins  49   b  do not touch the mesh belt  46 . The distance between the fins  49   b  and the mesh belt  46  at the closest point is preferably greater than or equal to 0.05 mm and less than or equal to 0.5 mm. 
     The mixing device  50  mixes the first screened material with an additive. The mixing device  50  has an additive supplier  52  that supplies an additive, a conduit  54  through which the first screened material MC and additive flow, and a mixing blower  56 . 
     One or more additive cartridges  52   a  storing additives are installed to the additive supplier  52 . The additive cartridges  52   a  may be removably installed to the additive supplier  52 . The additive supplier  52  includes an additive extractor  52   b  that extracts additive from the additive cartridges  52   a , and an additive injector  52   c  that injects the additive extracted by the additive extractor  52   b  into the conduit  54 . 
     The additive extractor  52   b  has a feeder (not shown in the figure) that feeds additive in a powder or particulate form from inside the additive cartridges  52   a , and removes additive from some or all of the additive cartridges  52   a . The additive removed by the additive extractor  52   b  is conveyed to the additive injector  52   c.    
     The additive injector  52   c  holds the additive removed by the additive extractor  52   b . The additive injector  52   c  has a shutter (not shown in the figure) that opens and closes the connection to the conduit  54 , and when the shutter is open, the additive extracted by the additive extractor  52   b  is fed into the conduit  54 . 
     The additive supplied from the additive supplier  52  includes resin (binder) that binds multiple fibers together when heated. The resin contained in the additive melts when passing through the sheet former  80  and 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 supplier  52  may 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 blower  56  produces an air current flowing through a conduit  54  connecting  7  to the air-laying device  60 . The first screened material MC conveyed from the  7  into the conduit  54 , and the additive supplied by the additive supply device  52  to the conduit  54 , are mixed as they pass through the mixing blower  56 . 
     The mixing blower  56  in 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 blower  56  may also include a mixer for mixing the first screened material and the additive. The mixture combined by the mixing device  50  is then conveyed by the air current produced by the mixing blower  56  to the air-laying device  60 , and introduced through the inlet  62  to the air-laying device  60 . 
     The air-laying device  60  detangles and causes the fibers in the mixture to disperse in air while precipitating to the second web former  70 . If the additive supplied from the additive supply device  52  is fibrous, these additive fibers are also detangled by the air-laying device  60  and descend to the second web former  70 . The second web former  70  accumulates the mixture precipitating from the air-laying device  60 , forming a second web W 2 . 
       FIG. 3  shows the basic configuration of the air-laying device  60  and second web former  70 , and shows the main parts thereof from the side. 
     As shown in  FIG. 1  and  FIG. 3 , the air-laying device  60  includes a drum  61 , and a housing  63  around the drum  61 . 
     The air-laying device  60  includes a drum  61 , and a housing  63  that houses the drum  61 . The drum  61  is configured as a cylindrical structure. 
     Like the drum  41  described above, drum  61  in this example is configured with a sieve. More specifically, the drum  61  has mesh, a filter or a screen with openings that functions as a sieve. More specifically, the drum  61  is cylindrical, and is rotationally driven centered on the axis of the cylinder by second sieve motor  60   a  (driver, sieve driver). At least part of the circumferential surface of the drum  61  is mesh. The mesh of the drum  61  may 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 drum  61  are identified as holes  61   a . The drum  61  turns as driven by the second sieve motor  60   a , functions as a sieve, and the mixture detangled by rotation of the drum  61  passes through the holes  61   a  and descends. The mixture that passes through the inlet  62  is referred to as mixture MX below. 
     The operating speed at which the drum  61  operates by driving the second sieve motor  60   a  is speed VD. This speed VD is also referred to as the rotational speed of the drum  61 . Note that the direction of rotation of the drum  61  is not limited to the direction shown in  FIG. 3 , and the drum  61  may be driven in reverse, or driven bidirectionally by the second sieve motor  60   a  alternating the direction of rotation. In addition, speed VD is not limited to the speed in the direction indicated by the arrow in  FIG. 3 , and may indicate the speed of the drum  61  relative to when the drum  61  is not turning. 
     The second web former  70  is located below the drum  61 . The second web former  70  in this example includes a mesh belt  72 , tension rollers  74 , and a suction mechanism  76 . 
     The mesh belt  72  is an endless metal belt similar to the mesh belt  46  described above, and is mounted around multiple tension rollers  74 . The mesh belt  72  circulates in a path configured by the tension rollers  74 . Part of the path of the mesh belt  72  is flat in the area below the drum  61 , and the mesh belt  72  forms a flat surface. There are also many holes in the mesh belt  72 . 
     One of the tension rollers  74  is a drive roller  74   a  that drives the mesh belt  72 . The drive roller  74   a  turns as driven by a second belt motor  74   b , and drives the mesh belt  74  in the direction indicated by the arrow in the figure. The operating speed at which the mesh belt  74  operates by the drive power of the second belt motor  74   b  is speed VC. This speed VC is also referred to as the conveyance speed of the mesh belt  72 . 
     A servo motor, stepper motor, or other known type of motor may be used for the second sieve motor  60   a  and second belt motor  74   b . Gears, links, or other transfer mechanisms that transfer power may also be disposed between the second sieve motor  60   a  and drum  61 , and between the drive roller  74   a  and second belt motor  74   b.    
     The mixture MX inside the drum  61  passes through the holes  61   a  by rotation of the drum  61 , and descends to the mesh belt  72 . Of the mixture MX descending from the drum  61 , components larger than the holes in the mesh belt  72  accumulate on the mesh belt  72 . Components of the mixture that are smaller than the holes in the mesh belt  72  pass through the holes. 
     A suction mechanism  76  is connected to a conduit  66 . The conduit  66  is connected through a second dust collector  67  to the second collection blower  68 . The second dust collector  67  has a filter that collects particles and fiber that pass through the mesh belt  72 . The second collection blower  68  is a blower that suctions air through the conduit  66 , and discharges the suctioned air outside the sheet manufacturing apparatus  100  or to a specific place in the sheet manufacturing apparatus  100 . 
     The suction mechanism  76  pulls air from below the mesh belt  72  by the suction of the second collection blower  68 , and collects particles and fiber contained in the suctioned air by the second dust collector  67 . The air current suctioned by the second collection blower  68  pulls the mixture descending from the drum  61  to the mesh belt  72 , and has the effect of promoting accumulation of the mixture on the mesh belt  72 . The air current suctioned by the suction device  48  creates a down flow in the path of the mixture descending from the drum  61 , and can be expected to have the effect of preventing the precipitating fibers from becoming tangled. The mixture MX accumulated on the support surface  71  is laid in a web on the flat part of the mesh belt  72 , forming a second web W 2 . 
     Referring again to  FIG. 1 , a wetting device  78  is disposed to the conveyance path of the mesh belt  72  downstream from the air-laying device  60 . The wetting device  78  is a mist humidifier that produces and supplies a water mist to the mesh belt  72 . The wetting device  78  in 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 W 2  can be adjusted by the mist supplied by the wetting device  78 , the mist can be expected to suppress accretion of fiber on the mesh belt  72  due to static electricity. 
     The second web W 2  is then conveyed by the conveyor  79 , separates from the mesh belt  72 , and is conveyed to the sheet former  80 . The conveyor  79  in this example has a mesh belt  79   a , rollers  79   b , and a suction mechanism  79   c . The suction mechanism  79   c  has a blower (not shown in the figure), and produces an air current upward through the mesh belt  79   a  by the suction of the blower. The second web W 2  is separated from the mesh belt  72  and pulled to the mesh belt  79   a  by this air current. The mesh belt  79   a  moves by rotation of the rollers  79   b , and conveys the second web W 2  to the sheet former  80 . 
     By applying heat to the second web W 2 , the sheet former  80  binds fibers recovered from the first screened material and contained in the second web W 2  through the resin contained in the additive. 
     The sheet former  80  has a compression device  82  that compresses the second web W 2 , and a heating device  84  that heats the second web W 2  after compression by the compression device  82 . 
     The compression device  82  comprises a pair of calender rolls  85 . The compression device  82  has a hydraulic press mechanism (not shown in the figure) that applies nip pressure to the calender rolls  85 , and a motor or other driver (not shown in the figure) that causes the calender rolls  85  to rotate in the direction of the heating device  84 . The compression device  82  compresses and conveys the second web W 2  to the heating device  84  with a specific nip pressure by the calender rolls  85 . 
     The heating device  84  includes a pair of heat rollers  86 . The heating device  84  also has a heater (not shown in the figure) that heats the surface of the heat rollers  86  to a specific temperature, and a motor or other driver (not shown in the figure) that causes the heat rollers  86  to rotate in the direction of the sheet cutter  90 . The heating device  84  holds and heats the second web W 2  compressed to a high density by the compression device  82 , and conveys the heated second web W 2  to the sheet cutter  90 . The second web W 2  is heated in the heating device  84  to a temperature greater than the glass transition temperature of the resin contained in the second web W 2 , forming a sheet S. 
     The sheet cutter  90  cuts the sheet S formed by the sheet former  80 . In this example, the sheet cutter  90  has a first cutter  92  that cuts the sheet S crosswise to the conveyance direction of the sheet S indicated by the arrow F in the figure, and a second cutter  94  that cuts the sheet S parallel to the conveyance direction F. The sheet cutter  90  cuts the length and width of the sheet S to a specific size, forming single sheets. The single sheets S cut by the sheet cutter  90  are then stored in the discharge tray  96 . The discharge tray  96  may 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 apparatus  100  embody a defibration processor  101  and a sheet maker  102 . The defibration processor  101  includes at least the defibrator  20 , and may include the classifier  40  and first web former  45 . 
     The defibration processor  101  makes defibrated material from feedstock material MA, or forms the defibrated material into a web configuration to make a first web W 1 . The work product of the defibration processor  101  may be conveyed through the rotor  49  to the mixing device  50 , or removed from the sheet manufacturing apparatus  100  without passing through the rotor  49  and stored. This work product can also be sealed in specific packages in a form ready for shipping or sale. 
     The sheet maker  102  is a functional device for making the work product manufactured by the defibration processor  101  into sheets S, and may be referred to as a processor. The sheet maker  102  includes the mixing device  50 , air-laying device  60 , second web former  70 , conveyor  79 , sheet former  80  and sheet cutter  90 , and may also include the rotor  49 . The sheet maker  102  may also include the additive supply device  52 . 
     The sheet manufacturing apparatus  100  may be configured with the defibration processor  101  and sheet maker  102  as a single integrated system, or with the defibration processor  101  and sheet maker  102  separate. In this case, the defibration processor  101  is an example of a fibrous feedstock recycling device according to the invention. The sheet maker  102  is 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 W 1  Forming Conditions 
     The forming conditions of the first web W 1  formed by the first web former  45  are described below with reference to  FIG. 2 . 
     The thickness of the first web W 1  is determined by the amount of first screened material MC, which is the material supplied to the mesh belt  46 , and the amount of movement of the mesh belt  46  per unit time. The amount of movement of the mesh belt  46  per unit time is speed VA shown in the figure. 
     One factor determining the amount of first screened material MC supplied to the mesh belt  46 , that is, the amount of first screened material MC passing through the openings  41   a , is the speed VB of the drum  41 . As speed VB increases, the defibrated material MB is more quickly defibrated in the drum  41 , and the first screened material MC passes more easily through the openings  41   a . In addition, the greater the speed VB, the more easily the first screened material MC passes the openings  41   a . Therefore, the amount of first screened material MC passing the openings  41   a  increases as the speed VB increases. 
     The amount of first screened material MC passing the openings  41   a  changes when the drum  41  starts moving from a stop. Because rotation of the drum  41  produces friction between the fibers of the first screened material MC inside the drum  41 , 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 openings  41   a.    
     On the other hand, when the drum  41  is 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 drum  41  starts turning from a stop, that is, when the drum  41  starts operating, the first screened material MC passes easily through the openings  41   a . The amount of first screened material MC passing the openings  41   a  therefore temporarily increases at this time. 
     The amount of first screened material MC passing the openings  41   a  is also affected by the humidity in the drum  41 . Humidity as used here can be referred to as relative humidity (RH). If the humidity inside the drum  41  is 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 drum  41 , the less variation there is in the amount of first screened material MC passing the openings  41   a.    
     In addition, if the humidity inside the drum  41  is 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 drum  41 , the greater the variation is in the amount of first screened material MC passing the openings  41   a.    
     The amount of first screened material MC passing the openings  41   a  also varies according to the length of the fiber in the first screened material MC. Short fibers pass through the openings  41   a  easily. Therefore, the shorter the fibers in the first screened material MC, the greater the amount of first screened material MC that passes the openings  41   a.    
     The greatest factor determining the amount of first screened material MC supplied from the drum  41  to the mesh belt  46  is therefore the speed VB of the drum  41 . Factors that change the amount of first screened material MC include whether or not the drum  41  is starting up, the humidity inside the drum  41 , and the length of fiber in the first screened material MC. 
     If the thickness of the first web W 1  varies, the amount of material supplied to processes downstream from the first web former  45  may vary, affecting the quality of the sheets S manufactured by the sheet manufacturing apparatus  100 . 
     The controller  150  of the sheet manufacturing apparatus  100  therefore executes a control process that suppresses variation in the thickness of the first web W 1 . 
     To execute control related to the thickness of the first web W 1 , the sheet manufacturing apparatus  100  has a first belt speed detector  322  ( FIG. 4 ) for detecting the speed VA, and a first sieve speed detector  321  ( FIG. 4 ) for detecting speed VB. 
     The sheet manufacturing apparatus  100  can also detect the humidity inside the drum  41 . For example, in this configuration the sheet manufacturing apparatus  100  has a first temperature/humidity detector  323  (humidity detector). The first temperature/humidity detector  323  can 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 detector  323  detects the temperature and the relative humidity of the space inside the drum  41 . The first temperature/humidity detector  323  may 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 apparatus  100  also has a first thickness detector  324 . The first thickness detector  324  is a sensor that detects the thickness of the first web W 1 . For example, the first thickness detector  324  may be an optical thickness sensor that has a light source and a photosensor, emits light to the first web W 1 , and detects the amount of light passing the first web W 1  to detect the thickness of the first web W 1 . The first thickness detector  324  may also be a contact thickness sensor having a probe that contacts the first web W 1 , and an encoder that detects the position of the probe, and detects the distance between the surface of the first web W 1  and the surface of the mesh belt  46 . The first thickness detector  324  may also be an ultrasonic thickness sensor, or a sensor that detects thickness by another method. 
     The controller  110  may also control adjusting the thickness of the first web W 1  based on the output of the first thickness detector  324 . For example, if the thickness detected by the first thickness detector  324  is outside a predetermined range, the controller  110  may stop the sheet manufacturing apparatus  100  or issue a warning. 
     1-3. Second Web Former Configuration 
     As shown in  FIG. 3 , the sheet manufacturing apparatus  100  may also have a second temperature/humidity detector  333  as a configuration for detecting the humidity inside the drum  61 . Like the first temperature/humidity detector  323 , the second temperature/humidity detector  333  can 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 detector  333  detects the temperature and the relative humidity of the space inside the drum  61 . The second temperature/humidity detector  333  may 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 apparatus  100  also has a second thickness detector  334 . The second thickness detector  334  is a sensor that detects the thickness of the second web W 2 . For example, the second thickness detector  334  may be an optical thickness sensor that has a light source and a photosensor, emits light to the second web W 2 , and detects the amount of light passing the second web W 2  to detect the thickness of the second web W 2 . The second thickness detector  334  may also be a contact thickness sensor having a probe that contacts the second web W 2 , and an encoder that detects the position of the probe, and detects the distance between the surface of the second web W 2  and the surface of the mesh belt  72 . The second thickness detector  334  may also be an ultrasonic thickness sensor, or a sensor that detects thickness by another method. 
     The controller  110  may also control adjusting the thickness of the second web W 2  based on the output of the second thickness detector  334 . For example, if the thickness detected by the second thickness detector  334  is outside a predetermined range, the controller  110  may stop the sheet manufacturing apparatus  100  or issue a warning. 
     1-4. Controller Configuration 
       FIG. 4  is a block diagram of the control system of the sheet manufacturing apparatus  100 . 
     The sheet manufacturing apparatus  100  has a controller  110  that has a main processor  111  configured to control parts of the sheet manufacturing apparatus  100 . 
     The controller  110  has a main processor  111 , ROM (Read Only Memory)  112 , and RAM (Random Access Memory)  113 . 
     The main processor  111  is embodied by a processor such as a CPU (central processing unit), and controls parts of the sheet manufacturing apparatus  100  by running a basic control program stored in ROM  112 . The main processor  111  may also be configured as a system chip including ROM  112 , RAM  113 , or other peripheral circuits, or other IP cores. 
     ROM  112  nonvolatilely stores programs executed by the main processor  111 . 
     RAM  113  provides working memory used by the main processor  111 , and temporarily stores programs the main processor  111  runs and data that is processed. 
     Nonvolatile storage  120  stores programs the main processor  111  executes, and data the main processor  111  processes. 
     The display panel  116  is an LCD or other type of display panel, and in this example is disposed externally to the sheet manufacturing apparatus  100 . The display panel  116  displays the operating status of the sheet manufacturing apparatus  100 , various settings, and warnings, for example. 
     The touch sensor  117  detects user operations by touch or pressure. In this example, the touch sensor  117  is disposed over the display surface of the display panel  116 , and detects operations on the display panel  116 . In response to operations, the touch sensor  117  outputs to the main processor  111  operating data including the operating position and the number of operating positions. Based on output from the touch sensor  117 , the main processor  111  detects operation of the display panel  116 , and acquires the operating positions. The main processor  111  enables GUI (graphical user interface) operations based on the operating position detected by the touch sensor  117 , and the display data  122  that was displayed on the display panel  116  when the operation was detected. 
     The controller  110  is connected through a sensor interface  114  to sensors disposed to parts of the sheet manufacturing apparatus  100 . The sensor interface  114  is an interface that acquires detection values output by the sensors, and inputs to the main processor  111 . The sensor interface  114  may include an A/D converter that converts analog signals output by the sensors to digital data. The sensor interface  114  may also supply drive current to the sensors. The sensor interface  114  may also include circuits that acquire sensor output values according to the sampling frequency controlled by the main processor  111 , and output to the main processor  111 . 
     The sensor interface  114  is also connected to a feedstock sensor  301 , and a paper discharge sensor  302 , for example. Also connected to the sensor interface  114  are the first sieve speed detector  321 , first belt speed detector  322 , first temperature/humidity detector  323 , and first thickness detector  324 . Additionally, the second sieve speed detector  331 , second belt speed detector  332 , second temperature/humidity detector  333 , and second thickness detector  334  are connected to the sensor interface  114 . 
     The first sieve speed detector  321  detects speed VB. The first sieve speed detector  321  may be configured with a rotary encoder and a sensor that contacts the rotary shaft or surface of the drum  41 , and detects the rotational speed. The first sieve speed detector  321  may also be a circuit disposed inside the first sieve motor  40   a , or configured as part of the first sieve motor  40   a , that outputs a signal indicating the number of revolutions or the rotational speed of the first sieve motor  40   a . The controller  110  may also function as the first sieve speed detector  321 , and calculate the rotational speed of the first sieve motor  40   a  based on the drive current of the first sieve motor  40   a.    
     The second sieve speed detector  331  detects speed VD, which is the operating speed of the drum  61 . The second sieve speed detector  331  may be configured identically to the first sieve speed detector  321 . 
     The first belt speed detector  322  detects speed VA, which is the operating speed of the mesh belt  46 . The first belt speed detector  322  detects the speed of mesh belt  46  movement, the rotational speed of the tension rollers  74 , or the rotational speed of the first belt motor  47   b . The first belt speed detector  322  may be configured with a speed sensor or rotary encoder. The first belt speed detector  322  may also be a circuit disposed inside the first belt motor  47   b , or configured as part of the first belt motor  47   b , that outputs a signal indicating the number of revolutions or the rotational speed of the first belt motor  47   b . The controller  110  may also function as the first belt speed detector  322 , and calculate the rotational speed of the first belt motor  47   b  based on the drive current of the first belt motor  47   b.    
     The second belt speed detector  332  detects speed VC, which is the operating speed of the mesh belt  72 . The second belt speed detector  332  may be configured identically to the second sieve speed detector  331 . 
     The feedstock sensor  301  detects the remaining amount of feedstock MA in the feedstock feeder  10 . The paper discharge sensor  302  detects how many sheets S are stored in the tray or stacker of the tray  96 . 
     The controller  110  is connected to the drivers of the sheet manufacturing apparatus  100  through a driver interface  115 . The drivers of the sheet manufacturing apparatus  100  include motors, pumps, and heaters, for example. The driver interface  115  may 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 shredder  311 , defibrator  312 , additive supplier  313 , blower  314 , humidifier  315 , drum driver  316 , separator  317 , and sheet cutter  318  are connected to the driver interface  115  as control objects of the controller  110 . 
     The shredder  311  in this example includes a motor or other drive device for turning the shredder blades  14 . 
     The defibrator  312  includes a motor or other drive device for turning the rotor (not shown in the figure) of the defibrator  20 . 
     The additive supplier  313  includes 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 blowers  314  include the first collection blower  28 , mixing blower  56 , and second collection blower  68 . These blowers may individually connect to the driver interface  115 . 
     The humidifier  315  includes the ultrasonic vibration generator (not shown in the figure) of the wetting device  78 , a fan (not shown in the figure), and a pump (not shown in the figure). 
     The drum driver  316  includes drivers such as a motor for turning drum  41 , and a motor for turning drum  61 . 
     The separator  317  includes a driver such as a motor (not shown in the figure) for turning the rotor  49 . 
     The sheet cutter  318  includes motors (not shown in the figure) for respectively operating the blades of the first cutter  92  and second cutter  94  of the sheet cutter  90 . 
     A motor for driving the calender rolls  85 , and a heater for heating the heat rollers  86 , may also be connected to the driver interface  115 . 
     A first sieve motor  40   a , first belt motor  47   b , second sieve motor  60   a , and second belt motor  74   b  are also connected to the driver interface  115 . The controller  110  can control these motors to start turning and stop turning. The controller  110  can also control the speed of the first sieve motor  40   a  and first belt motor  47   b.    
       FIG. 5  is a function block diagram of the controller  110 . 
     The controller  110  embodies various function units by the cooperation of hardware and software resulting from a main processor  111  running a program.  FIG. 5  shows the functions of the main processor  111  embodying these function units as controller  150 . The controller  110  also configures storage  160 , which is a logical storage device, using the memory area of the nonvolatile storage  120 . The storage  160  may be configured using memory areas in ROM  112  and RAM  113 . 
     The controller  150  has a detection controller  151  and a drive controller  152 . These controllers are embodied by the main processor  111  running a program. The controller  110  may also execute an operating system (OS) as a basic control program for controlling the sheet manufacturing apparatus  100  and configuring a platform for running application programs. In this case, the function units of the controller  150  may be embodied as application programs. 
     In  FIG. 5 , detectors controlled by the controller  150  include the first sieve speed detector  321 , first belt speed detector  322 , first temperature/humidity detector  323 , and first thickness detector  324 . A second sieve speed detector  331 , second belt speed detector  332 , second temperature/humidity detector  333 , and second thickness detector  334  are also shown. These sensors are collectively referred to as sensors  300 . 
       FIG. 5  also shows the first sieve motor  40   a , first belt motor  47   b , second sieve motor  60   a , and second belt motor  74   b  as drivers controlled by the controller  150 . These other drivers are collectively referred to as driver  310 . 
     The storage  160  stores data processed by the controller  150 . In this example, the storage  160  more specifically stores settings data  161 , reference data  162 , and speed setting data  163 . 
     The settings data  161  is generated by operating the touch sensor  117 , or based on commands and data input through a communication interface (not shown in the figure) of the controller  110 , and stored in storage  160 . 
     The settings data  161  include various settings related to operation of the sheet manufacturing apparatus  100 . For example, the settings data  161  may include the number of sheets S manufactured by the sheet manufacturing apparatus  100 , the type and color of sheets S, operating conditions for parts of the sheet manufacturing apparatus  100 , and other settings. The settings data  161  also includes a setting input through the touch sensor  117  related to the length of fiber in the feedstock material MA the sheet manufacturing apparatus  100  processes. For example, when the feedstock material MA is sheets S that were manufactured by the sheet manufacturing apparatus  100  and contain fiber that has been processed multiple times by the sheet manufacturing apparatus  100 , and when the feedstock material MA contains fiber sourced from deciduous trees, the feedstock material MA contains short fibers. The settings data  161  may 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 data  162  includes reference values for evaluating the operating conditions for making sheets S in the sheet manufacturing apparatus  100 . More specifically, the reference data  162  includes a reference value for determining whether the humidity detected by the first temperature/humidity detector  323  is high or low. 
     The reference data  162  may also include reference values for evaluations related to the speed detected by the first sieve speed detector  321 , first belt speed detector  322 , second sieve speed detector  331 , and second belt speed detector  332 . 
     The reference data  162  may also include standards for evaluating the detection values output from the first thickness detector  324  and second thickness detector  334 . 
     The reference values included in the reference data  162  may be a single value, or range values including maximum and minimum values for a range. 
     The speed setting data  163  includes data for the controller  150  to control the speed of the first belt motor  47   b . When the sheet manufacturing apparatus  100  starts, the controller  150  causes the first sieve motor  40   a  and first belt motor  47   b  to accelerate, and operates the drum  41  and mesh belt  46  at a speed suitable for making a sheet S. The sheet manufacturing apparatus  100  starting means the sheet manufacturing apparatus  100  starting the operation for making a sheet S from a stop. To suppress variation in the thickness of the first web W 1  in this process, the controller  150  increases speed VA from speed 0. 
     The speed setting data  163  includes data related to speed when accelerating the mesh belt  46  from a stopped state to speed VA. For example, the speed setting data  163  includes data related to speed conditions defining the correlation between time and speed VA when accelerating the mesh belt  46  from speed 0. The speed conditions may be conditions defining the change in speed, which may be referred to as the speed pattern. 
     The detection controller  151  controls detected by the sensors  300 , and acquires the detection values from the sensors. The detection controller  151  also acquires the detection values from the first sieve speed detector  321 , first belt speed detector  322 , first temperature/humidity detector  323 , and first thickness detector  324 . The detection controller  151  also acquires the detection values from the second sieve speed detector  331 , second belt speed detector  332 , second temperature/humidity detector  333 , and second thickness detector  334 . 
     By controlling the driver  310  based on the detection values of the sensors  300  acquired by the detection controller  151 , the drive controller  152  operates parts of the sheet manufacturing apparatus  100  according to the values in the settings data  161 , and manufactures a sheet S. 
     The drive controller  152  drives the first sieve motor  40   a , first belt motor  47   b , second sieve motor  60   a , and second belt motor  74   b . Based on the detection values of the first sieve speed detector  321  and first belt speed detector  322  acquired by the detection controller  151 , the drive controller  152  controls the speed of the first sieve motor  40   a  and first belt motor  47   b . As a result, speed VA and speed VB are adjusted to the set speeds. 
     Based on the detection values of the second sieve speed detector  331  and second belt speed detector  332  acquired by the detection controller  151 , the drive controller  152  controls the speed of the second sieve motor  60   a  and second belt motor  74   b . As a result, speed VC and speed VD are adjusted to the set speeds. 
     The drive controller  152  sets the speed conditions of the first belt motor  47   b  when starting the drum  41  and mesh belt  46  from a stop. The speed conditions are data defining the rate of acceleration when accelerating the first belt motor  47   b  from a full stop. The drive controller  152  sets the speed conditions based on the detection values of the first temperature/humidity detector  323  acquired by the detection controller  151 , the settings data  161 , reference data  162 , and speed setting data  163 . 
     1-5. Sheet Manufacturing Apparatus Operation 
       FIG. 6  and  FIG. 7  are flow charts of the operation of the sheet manufacturing apparatus  100 , and describe the operation of starting the sheet manufacturing apparatus  100  from when the sheet manufacturing apparatus  100  is stopped. The operation shown in  FIG. 6  and  FIG. 7  is executed by the drive controller  152  of the controller  150 . 
     The controller  150  first executes a setup process related to first belt motor  47   b  operation (step ST 1 ). The setup process of step ST 1  is a process of making settings related to the speed of the first belt motor  47   b  when the first sieve motor  40   a  starts operating. This setup process is described below with reference to  FIG. 7 . 
     After the setup process, the controller  150  starts the startup sequence (step ST 2 ). The startup sequence is a sequence of operations sequentially starting parts of the sheet manufacturing apparatus  100  from the stopped state of the sheet manufacturing apparatus  100 . More specifically, the startup sequence starts the shredder  12 , defibrator  20 , classifier  40 , first web former  45 , rotor  49 , mixing device  50 , air-laying device  60 , second web former  70 , sheet former  80 , and sheet cutter  90  from the stopped state. 
     When the startup sequence starts, the controller  150  controls the humidifier  315  to start operation of the wetting device  78  (step ST 3 ). If the sheet manufacturing apparatus  100  has devices other than the wetting device  78  that add humidity, the controller  150  also starts those devices in step ST 3 . 
     Next, the controller  150  starts the blower  314  (step ST 4 ), and starts the defibrator  312  and thereby starts the defibrator  20  turning (step ST 5 ). The defibrator  20  then accelerates to a previously set speed, and thereafter operates at a constant speed. 
     Next, the controller  150  starts the shredder  311  (step ST 6 ). After step ST 6 , feedstock containing fiber is supplied to the shredder  311 . 
     The controller  150  also starts the first sieve motor  40   a  and first belt motor  47   b , and starts driving the drum  41  and mesh belt  46  of the classifier  40  (step ST 7 ). In step ST 7 , the first belt motor  47   b  is started and the speed of the first belt motor  47   b  increases according to the conditions set in step ST 1 . Also in step ST 7 , the controller  150  starts the first sieve motor  40   a , and accelerates the first sieve motor  40   a  according to a previously set target speed and rate of acceleration. 
     Next, the controller  150  starts the second sieve motor  60   a  and second belt motor  74   b , and starts the drum  61  and mesh belt  72  (step ST 8 ). The controller  150  then starts operation of the calender rolls  85  and heat rollers  86  of the sheet former  80  (step ST 9 ), and completes the startup sequence. 
       FIG. 7  is a flow chart of the setup process executes in step ST 1  in  FIG. 6 . 
     The controller  150  first determines if there is defibrated material MB inside the drum  41  (step ST 21 ). Whether or not there is any defibrated material MB may be determined based on input from the touch sensor  117 , for example. 
     If there is no defibrated material MB inside the drum  41  (step ST 21 : NO), the controller  150  sets a first speed condition as the condition for accelerating the speed of the first belt motor  47   b  (step ST 22 ), and ends the setup process. 
     If there is defibrated material MB inside the drum  41  (step ST 21 : YES), the controller  150  determines whether or not the humidity detected by the first temperature/humidity detector  323  is greater than or equal to the reference value contained in the reference data  162  (step ST 23 ). If the humidity is greater than or equal to the reference value (step ST 23 : YES), the controller  150  determines if the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data  162  (step ST 24 ). 
     If the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data  162  (step ST 24 : YES), the controller  150  sets a second speed condition as the condition for accelerating the speed of the first belt motor  47   b  (step ST 25 ), and ends the setup process. 
     If the length of fiber contained in the defibrated material MB is shorter than the reference value (step ST 24 : NO), the controller  150  sets a third speed condition as the condition for accelerating the speed of the first belt motor  47   b  (step ST 26 ), and ends the setup process. 
     However, if the humidity is less than the reference value (step ST 23 : NO), the controller  150  determines if the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data  162  (step ST 27 ). 
     If the length of fiber contained in the defibrated material MB is greater than or equal to the reference value (step ST 27 : YES), the controller  150  sets a fourth speed condition as the condition for accelerating the speed of the first belt motor  47   b  (step ST 28 ), and ends the setup process. 
     If the length of fiber contained in the defibrated material MB is shorter than the reference value (step ST 27 : NO), the controller  150  sets a fifth speed condition as the condition for accelerating the speed of the first belt motor  47   b  (step ST 28 ), and ends the setup process. 
     The first to fifth speed conditions are basic conditions for accelerating from zero to speed VB when starting the drum  41 , and include a target speed for the first belt motor  47   b , and either the time for acceleration to the target speed or the acceleration rate of the first belt motor  47   b.    
       FIG. 8  is a graph showing an example of the operating speed VA of the mesh belt  46  and change in thickness of the first web W 1 .  FIG. 8  (1) indicates the speed VA detected by the first belt speed detector  322 , (2) indicates the detection value of the first web W 1  detected by the first thickness detector  324 , and (3) indicates the speed VB of the drum  41  detected by the first sieve speed detector  321 . 
     The Y-axes indicate speeds VA and VB, and the thickness of the first web W 1 , and coordinate 0 on the Y-axis indicates speed 0 (stopped) and the first web W 1  thickness 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 motor  40   a  and first belt motor  47   b  start operating is time T 1 . 
     The target value set for the thickness of the first web W 1  is thickness TH 1 . In this operating example, the thickness of the first web W 1  is ideally held constant at thickness TH 1 . The thickness TH 1  is set to a value in the range 2 mm to 10 mm in this example, but may be set thicker or thinner. 
       FIG. 8  is an example of a the controller  150  controlling the first sieve motor  40   a  and first belt motor  47   b  according to the first speed condition. 
     In the examples shown in  FIG. 8  and  FIG. 9  to  FIG. 11  described below, the target speed for speed VA is set to speed V 1 . This target speed V 1  is the speed VA when the sheet manufacturing apparatus  100  makes sheets S, and is an example of a first speed in the invention. The target speed V 1  may 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 drum  41  is set to a value in the range 50 rpm-1000 rpm for example. 
     As shown in  FIG. 8 , after starting the first sieve motor  40   a  at time T 1 , the controller  150  accelerates the first sieve motor  40   a  until speed VB reaches target speed V 11 , and thereafter holds speed VB at speed V 11 . This speed V 11  is the speed VB when the sheet manufacturing apparatus  100  manufactures sheets S, and is an example of a third speed in the invention. 
     Note that in this example the time from when the mesh belt  46  starts until speed VA reaches speed V 11  is referred to as the speed adjustment period. 
     The first speed condition is the condition enabling speed VA to reach target speed V 1  by time T 2 . In other words, the speed adjustment period is period TE 1  from time T 1  to time T 2 . Period TE 1  is 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 motor  47   b . The controller  150  drives the drive roller  47   a  to accelerate at a default acceleration rate after starting the first belt motor  47   b , and stops acceleration when speed VA reaches target speed V 1 . The time required for this acceleration is the speed adjustment period. 
     As described above, when the drum  41  starts operating with defibrated material MB inside the drum  41 , the amount of first screened material MC falling from the drum  41  is temporarily greater than when defibrated material MB is not in the drum  41 . As a result, the amount of first screened material MC dropping to the mesh belt  46  after the first sieve motor  40   a  starts turning is temporarily greater than the amount suitable for making a sheet S. As a result, as indicated by the (2) in  FIG. 8 , the thickness of the first web W 1  exceeds thickness TH 1 , and the peak thickness TH 2  is significantly greater than thickness TH 1 . 
     In the setup process shown in  FIG. 7 , the controller  150  sets one of the second to fifth speed conditions when defibrated material MB is already inside the drum  41 . 
     The second to fifth speed conditions each set the speed adjustment period longer than period TE 1 , and provide a period during the speed adjustment period in which speed VA reaches a speed greater than target speed V 1 . By reaching a speed VA greater than the target speed V 1 , the speed of the mesh belt  46  moving below the drum  41  increases, and the amount of first screened material MC per unit area of the mesh belt  46  decreases. As a result, the thickness of the first web W 1  accumulating on the mesh belt  46  decreases. Increasing the thickness of the first web W 1  can be suppressed by setting speed VA to a higher speed while the amount of first screened material MC falling from the drum  41  is high. The speed adjustment period in this case is the time until the speed VA reaches the target speed V 1 , and the speed VA during the speed adjustment period is greater than the target speed V 1 , but speed VA may be less than target speed V 1  temporarily. 
     In the second speed condition, defibrated material MB is in the drum  41 , the humidity detected by the first temperature/humidity detector  323  is 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 TE 1 . In the second speed condition, speed VA is greater than target speed V 1  for 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 drum  41 , the humidity detected by the first temperature/humidity detector  323  is lower than to the reference value, and the fiber length is greater than or equal to the reference value. Because the humidity inside the drum  41  is lower than when the second speed condition is set, the amount of first screened material MC falling from the drum  41  increases temporarily. As a result, the fourth speed condition is a condition whereby the thickness of the first web W 1  accumulated on the mesh belt  46  becomes 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 drum  41 , the humidity detected by the first temperature/humidity detector  323  is 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 drum  41  increases temporarily. As a result, the third speed condition is a condition whereby the thickness of the first web W 1  accumulated on the mesh belt  46  becomes 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 drum  41  on the amount of first screened material MC that drops from the drum  41 , 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 drum  41 , is greater. 
     When the effect of humidity inside the drum  41  on 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 W 1  is 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 drum  41  on 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 W 1  is 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 drum  41 , the humidity detected by the first temperature/humidity detector  323  is 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 W 1  is 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 drum  41  to the mesh belt  46  may increase temporarily, the controller  150  sets the speed VA during the speed adjustment period greater than target speed V 1  when the first belt motor  47   b  starts operating. As a result, the controller  150  suppresses variation in the thickness of the first web W 1 , and in the process of the sheet manufacturing apparatus  100  making sheets S, the amount of first screened material MC supplied to processes downstream from the first web former  45  can 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 , and  FIG. 11  are graphs showing examples of the operating speed VA of the mesh belt  46  and change in the thickness of the first web W 1  when the second to fifth speed conditions are set. 
     In these figures, (1) indicates speed VA detected by the first belt speed detector  322 , and (2) indicates the thickness of the first web W 1  detected by the first thickness detector  324 . The Y-axis, X-axis, target speed V 1 , thickness TH 1  and TH 2 , and time T 1  are the same as in  FIG. 8 . For comparison, these figures also show time T 2  from  FIG. 8 . 
       FIG. 9  shows an example in which the speed VA changes in steps, and more specifically an example in which speed VA changes in two steps. The controller  150  sets a period for holding an intermediate speed V 2  that is lower than the target speed V 1  before starting accelerating speed VA to target speed V 1 . More specifically, the controller  150  starts turning the first belt motor  47   b  at time T 1 , and accelerates the first belt motor  47   b  so that speed VA reaches intermediate speed V 2  at time T 2 . The controller  150  then holds speed VA at intermediate speed V 2  until time T 3 , then decelerates the first belt motor  47   b  from time T 3  to time T 4  to reach target speed V 1  at time T 4 . 
     The speed adjustment period is indicated by reference numeral TE 2  in the example in  FIG. 9 . This speed adjustment period TE 2  is an example of a first period. The speed adjustment period TE 2  (time T 1 -T 4 ) is longer than the period from time T 1 -T 2 . In addition, speed VA in the speed adjustment period TE 2  is greater than target speed V 1 . As a result, the controller  150  holds speed VA at a speed greater than target speed V 1  during the speed adjustment period TE 2  after the first belt motor  47   b  starts turning. As shown in  FIG. 9  (2), the detection value of the first thickness detector  324  varies from around time T 2 , but the peak thickness TH 3  of the first web W 1  is less than the peak thickness TH 2  shown in  FIG. 8 . It is thus obvious that variation in the thickness of the first web W 1  is suppressed. 
       FIG. 10  shows an example in which the speed VB changes in steps, and more specifically an example in which speed VB changes in multiple steps. The controller  150  sets multiple periods for holding speed VA at intermediate speeds V 3 , V 4  and V 5  that are lower than the target speed V 1  during the speed adjustment period TE 2  (time T 1  to T 10 ). More specifically, the controller  150  starts turning the first belt motor  47   b  at time T 1 , and accelerates the first belt motor  47   b  so that speed VA reaches intermediate speed V 3  at time T 2 . The controller  150  then holds speed VA at intermediate speed V 3  from time T 2  to time T 5 , and at time T 5  slows the first belt motor  47   b  so that speed VA reaches intermediate speed V 4  at time T 6 . The controller  150  then holds speed VA at intermediate speed V 4  from time T 6  to time T 7 , and at time T 7  slows the first belt motor  47   b  so that speed VA reaches intermediate speed V 5  at time T 8 . The controller  150  then holds speed VA at intermediate speed V 3  from time T 8  to time T 9 , and at time T 9  slows the first belt motor  47   b  so that speed VA reaches intermediate speed V 1  at time T 10 . 
     In the example in  FIG. 10 , the speed adjustment period TE 2  is from time T 1  to time T 10 . This speed adjustment period TE 2  is longer than the period from time T 1  to time T 2  in  FIG. 8 . The controller  150  thus holds the speed VA above the target speed V 1  during the speed adjustment period TE 2  after the first belt motor  47   b  starts turning. 
     As shown by curve (2) in  FIG. 10 , the value detected by the first thickness detector  324  fluctuates from approximately time T 11 , but the peak thickness TH 4  of the first web W 1  is less than the peak thickness TH 2  shown in  FIG. 8 . More specifically, the peak thickness TH 4  is successfully suppressed by inserting a speed adjustment period TE 2  in which the speed is greater than the target speed V 1  immediately after the drum  41  starts turning when the amount of first screened material MC passing through the drum  41  increases easily. 
     As shown in  FIG. 9  and  FIG. 10 , the controller  150  can 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 controller  150  may also be configured to not maintain the speed VA at a constant rate during the speed adjustment period TE 2 . In this case, the controller  150  may control a linear change in the speed VA. More specifically, the first belt motor  47   b  may be operated so that the rate of change in the speed VA maintains a constant rate of acceleration. The controller  150  may also control the first belt motor  47   b  so that the acceleration rate of speed VA changes during the speed adjustment period TE 2 . Each of these configurations can be expected to suppress variation in the first web W 1  insofar as the period TE 1  is longer than from time T 1  to time T 2 , and speed VA is greater than the target speed V 1  during the speed adjustment period TE 2 . 
       FIG. 11  shows an example of the controller  150  controlling the speed of the first belt motor  47   b  based on the detection value received from the first thickness detector  324 , that is, an example of feedback control. In this example, the length of the speed adjustment period TE 2  is set as an operating condition of the first belt motor  47   b . The operating conditions of the first belt motor  47   b  may also include the minimum speed VA during the speed adjustment period TE 2 . 
     In the example in  FIG. 11 , the controller  150  starts accelerating the first belt motor  47   b , and starts acquiring the detection value from the first thickness detector  324 , at time T 1 . The controller  150  increases or decreases the speed of the first belt motor  47   b  according to the difference between the detection value from the first thickness detector  324  and a threshold value. The threshold value related to the detection value of the first thickness detector  324  may be thickness TH 1 , or another value included in the reference data  162 . 
     In the example in  FIG. 11 , speed VA is greater than target speed V 1  for at least part of the speed adjustment period TE 2 . The controller  150  decelerates the first belt motor  47   b  from time T 11  so that the speed VA goes to target speed V 1  at time T 12  according to the length of the speed adjustment period TE 2  defined by the speed conditions. 
     In the example in  FIG. 11 , the second to fifth speed conditions may contain little information, such as information indicating the length of the speed adjustment period TE 2 , 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 in  FIG. 9  to  FIG. 11 . For example, all of the second to fifth speed conditions can use the two step acceleration pattern shown in  FIG. 9 . In this case, the second to fifth speed conditions may include information indicating the length of the speed adjustment period TE 2 , or information indicating the maximum and/or minimum speed VA in the speed adjustment period TE 2 . In addition, the second to fifth speed conditions may include patterns that change the speed VA as shown in  FIG. 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 in  FIG. 9  to  FIG. 11 . 
     Furthermore, in the examples in  FIG. 9  to  FIG. 10 , speed VA is held constant after reaching target speed V 1 , but speed VA does not need to remain constant at target speed V 1  throughout 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 apparatus  100 . 
     As described above, a sheet manufacturing apparatus  100  according to the first embodiment of the invention has a drum  41  that sieves first screened material MC, which is material containing fiber, and a first web former  45  that accumulates first screened material MC discharged from the drum  41 . The sheet manufacturing apparatus  100  also has the parts of a sheet maker  102  that processes the first web W 1 , that is, the first screened material MC, accumulated in the first web former  45 . 
     During processing by the processor, the sheet manufacturing apparatus  100  operates the mesh belt  46  of the first web former  45  at a target speed V 1 . When starting from a state in which the drum  41  is stopped (not turning), a startup operation including a state in which the mesh belt  46  operates at a faster speed than the target speed V 1  during the speed adjustment period TE 2  is executed. The processor may include any of the processes executed after the first web former  45 , and may be selected from among any of the parts of the sheet maker  102 , for example. 
     In a sheet manufacturing apparatus  100  applying the fiber processing device and control method of a fiber processing device according to the invention, the speed VA at which the mesh belt  46  operates during the speed adjustment period TE 2  is greater than the target speed V 1 . As a result, even if the amount of first screened material MC discharged from the drum  41  increases briefly, an increase in the thickness of the first web W 1  accumulated in the first web former  45  can be suppressed. 
     The sheet manufacturing apparatus  100  also maintains a state in which the first web former  45  operates at a greater speed than the target speed V 1  during the speed adjustment period TE 2 . For example, a period in which speed VA is greater than target speed V 1  is maintained in the examples shown in  FIG. 9  to  FIG. 11 . Holding speed VA greater than target speed V 1  when the amount of first screened material MC dropping from the drum  41  may easily increase can be expected to effectively suppress variation in the thickness of the first web W 1  due to temporary variations in the amount of first screened material MC. 
     The first web former  45  also has a mesh belt  46  that an accumulate the first screened material MC in a sheet, and the mesh belt  46  moves in a circulating path defined by the tension rollers  47 . Therefore, by setting the speed VA at which the mesh belt  46  moves faster than the target speed V 1 , variation in the thickness of the first web W 1  accumulated on the mesh belt  46  can be suppressed. 
     During processing by the processor, the sheet manufacturing apparatus  100  drives the mesh belt  46  at a target speed V 1 , and in the speed adjustment period TE 2 , maintains the operating speed of the mesh belt  46  at a second speed that is faster than the target speed V 1 . This configuration can effectively suppress variation in the thickness of the first web W 1  due to temporary variation in the amount of first screened material MC in the speed adjustment period TE 2  because the mesh belt  46  operates at a higher speed than the target speed V 1  for the speed VA when making sheets S. 
     When the sheet manufacturing apparatus  100  starts from a state in which the drum  41  is stopped, the operating speed of the mesh belt  46  may accelerate to a higher speed than the target speed V 1  before the drum  41  starts turning. In this case, during a second period after acceleration ends, the first belt motor  47   b  continues driving the mesh belt  46  at a faster speed than target speed V 1 . Because the speed VA exceeds the target speed V 1  during the time when the amount of first screened material MC dropping from the drum  41  increases easily, this configuration can effectively suppress variation in the thickness of the first web W 1  due to temporary variations in the amount of first screened material MC. 
     When starting from a state in which the drum  41  is stopped, the sheet manufacturing apparatus  100  executes a startup operation when there is defibrated material MB inside the drum  41 . Because speed VA thus exceeds the target speed V 1  during the time when the amount of first screened material MC dropping from the drum  41  increases easily, this configuration can effectively suppress variation in the thickness of the first web W 1  due 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 drum  41  does not vary easily, a drop in productivity manufacturing sheets S can be prevented. 
     The drum  41  is a round cylinder having openings formed in the outside surface of the drum  41 , and configured to rotate on the axis of the cylinder. When the drum  41  starts turning with defibrated material MB inside the drum  41 , the amount of first screened material MC that drops onto the mesh belt  46  when operation starts can fluctuate easily. Variation in the thickness of the first web W 1  due to variation in the amount of first screened material MC can be suppressed in this configuration because a period in which the mesh belt  46  moves at a speed greater than the target speed V 1  is maintained by the controller  150 . 
     A sheet manufacturing apparatus  100  applying the fibrous feedstock recycling device of the invention has a defibrator  20  as a refiner that refines feedstock material MA containing fiber. The sheet manufacturing apparatus  100  also has a drum  41  that sieves the defibrated material MB refined by the refiner, and a first web former  45  as an accumulator that accumulates first screened material MC discharged from the drum  41 . The sheet manufacturing apparatus  100  also has the parts of the sheet maker  102  as a processor that processes the first screened material MC accumulated on the first web former  45 . While the sheet manufacturing apparatus  100  is making sheets S, the first web former  45  operates at a target speed V 1 . When the sheet manufacturing apparatus  100  starts from when the drum  41  is at a stop, a startup operation including a state in which the first web former  45  operates at a faster speed than the target speed V 1  during the speed adjustment period TE 2  after the drum  41  starts executes. As a result, an increase in the thickness of the first web W 1  accumulated in the first web former  45  when the amount of first screened material MC moving from the drum  41  easily varies can be suppressed. 
     2. Embodiment 2 
     A second embodiment of the invention is described below. 
     The second embodiment describes an operation suppressing variation in the thickness of the first web W 1  by the drive controller  152  controlling the speed VA of the mesh belt  46  and the speed VB of the drum  41  in the startup operation. The configuration of the sheet manufacturing apparatus  100  according to the second embodiment of the invention is the same as in the first embodiment, further description of the configuration of the sheet manufacturing apparatus  100  is omitted in the drawings and below. 
     In this second embodiment, the controller  150  executes the same operation shown in  FIG. 6  as the first embodiment. In step ST 7 , the controller  150  controls the first belt motor  47   b  and first sieve motor  40   a  according to the operating conditions set in step ST 1 . 
       FIG. 12  is a flow chart of the setup process executed in step ST 1  in  FIG. 6 . 
     The setup process in the second embodiment also sets operating conditions related to controlling the first sieve motor  40   a . The operating conditions set in the second embodiment include information relating to operation of the first belt motor  47   b , and information relating to operation of the first sieve motor  40   a . In the first embodiment, the first to fifth speed conditions include information related to the length of the speed adjustment period TE 2 , 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 TE 3  until speed VB reaches target speed V 1  used when making sheets S. 
     In the setup process of  FIG. 12 , the controller  150  determines if there is defibrated material MB in the drum  41  (step ST 31 ). 
     If there is no defibrated material MB inside the drum  41  (step ST 31 : NO), the controller  150  sets a first speed condition as the condition for accelerating the speed of the first sieve motor  40   a  and first belt motor  47   b  (step ST 32 ), and ends the setup process. 
     If there is defibrated material MB in the drum  41  (step ST 31 : YES), the controller  150  determines whether or not the humidity detected by the first temperature/humidity detector  323  is greater than or equal to the reference value contained in the reference data  162  (step ST 33 ). If the humidity is greater than or equal to the reference value (step ST 33 : YES), the controller  150  determines if the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data  162  (step ST 34 ). 
     If the length of fiber is greater than or equal to the reference value (step ST 34 : YES), the controller  150  sets a second speed condition as the condition for accelerating the speed of the first sieve motor  40   a  and first belt motor  47   b  (step ST 35 ), and ends the setup process. 
     If the length of fiber is shorter than the reference value (step ST 34 : NO), the controller  150  sets a third speed condition as the condition for accelerating the speed of the first sieve motor  40   a  and first belt motor  47   b  (step ST 36 ), and ends the setup process. 
     However, if the humidity is less than the reference value (step ST 33 : NO), the controller  150  determines if the length of fiber contained in the defibrated material MB is greater than or equal to the reference value contained in the reference data  162  (step ST 37 ). 
     If the length of fiber is greater than or equal to the reference value (step ST 37 : YES), the controller  150  sets a fourth speed condition as the condition for accelerating the speed of the first sieve motor  40   a  and first belt motor  47   b  (step ST 38 ), and ends the setup process. 
     If the length of fiber is shorter than the reference value (step ST 37 : NO), the controller  150  sets a fifth speed condition as the condition for accelerating the speed of the first sieve motor  40   a  and first belt motor  47   b  (step ST 39 ), and ends the setup process. 
       FIG. 13  is a graph showing the change in the speed VB of the drum  41  and the thickness of the first web W 1 , and shows an example of the operation when the second to fifth speed conditions are set in the setup process of  FIG. 12 . In  FIG. 13  and  FIG. 14 , The Y-axis, X-axis, target speed V 1 , thickness TH 1  and TH 2 , and time T 1  are the same as in  FIG. 8 . 
     In  FIG. 13 , curve (1) indicates the speed VB detected by the first sieve speed detector  321 , and (2) indicates the thickness of the first web W 1 . As described above, speed V 11  is the speed VB when making sheets S, and in the startup operation, the controller  150  accelerates the first sieve motor  40   a  until the speed VB of the drum  41  reaches speed V 11 . Time T 1  when acceleration of the first sieve motor  40   a  and first belt motor  47   b  starts is the same as in  FIG. 8  and described above. 
     The time from when the controller  150  starts the first sieve motor  40   a  to when speed VB reaches speed V 11  is period TE 3 .  FIG. 13  shows an example of changing speed VB in steps, and more specifically is an example of changing speed VB in two steps. In period TE 3 , the controller  150  provides a period in which speed VB is held at an intermediate speed V 12  that is below speed V 11 . More specifically, the controller  150  starts turning the first sieve motor  40   a  at time T 1 , and accelerates the first sieve motor  40   a  so that speed VB reaches intermediate speed V 12  at time T 21 . The controller  150  then holds speed VB at intermediate speed V 12  from time T 21  to time T 22 , then accelerates the first sieve motor  40   a  again from time T 22  to reach target speed V 1  at time T 23 . 
     In the example in  FIG. 13 , the time T 23  at which speed VB reaches target speed V 11  is after time T 2  described above. In other words, the controller  150  holds speed VB at a speed less than target speed V 11  for period TE 3  (from time T 1  to time T 23 ) after the first sieve motor  40   a  starts turning. As shown by (2) in  FIG. 13 , the value detected by the first thickness detector  324  fluctuates from approximately time T 21 , but the peak thickness TH 11  of the first web W 1  is less than the peak thickness TH 2  shown in  FIG. 8 . This demonstrates that variation in the thickness of the first web W 1  is suppressed. 
     The second to fifth speed conditions include information specifying the length of the acceleration time TE 3 , time T 23 , and speed VB in period TE 3  (intermediate speed V 12 , for example), for controlling the first sieve motor  40   a.    
     The controller  150  also executes the startup operation of the first belt motor  47   b  according 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. 14  is a graph showing an example of change in the speed VA of the mesh belt  46  and the thickness of the first web W 1 , and shows an example of when second to fifth speed conditions are set. In  FIG. 14 , line (1) indicates the speed VA detected by the first belt speed detector  322 , and (2) indicates the thickness of the first web W 1  detected by the first thickness detector  324 . 
     In  FIG. 14 , the controller  150  controls the speed of the first belt motor  47   b  based on the detection value from the first thickness detector  324 , that is, is an example of feedback control. In this example, the length of the speed adjustment period TE 2  is set as an operating condition of the first belt motor  47   b . The operating conditions of the first belt motor  47   b  may also include the minimum speed VA during the speed adjustment period TE 2 . 
     In the example in  FIG. 14 , the controller  150  starts accelerating the first belt motor  47   b , and starts acquiring the detection value from the first thickness detector  324 , at time T 1 . The controller  150  increases or decreases the speed of the first belt motor  47   b  according to the difference between the detection value from the first thickness detector  324  and a threshold value. The threshold value related to the detection value of the first thickness detector  324  may be thickness TH 1 , or another value included in the reference data  162 . 
     In the example in  FIG. 14 , speed VA is greater than target speed V 1  for at least part of the speed adjustment period TE 2  (time T 1  to time T 25 ). The controller  150  decelerates the first belt motor  47   b  from time T 11  so that the speed VA goes to target speed V 1  at time T 25  according to the length of the speed adjustment period TE 2  defined by the speed conditions. 
     In the example in  FIG. 14 , the second to fifth speed conditions may contain little information, such as information indicating the length of the speed adjustment period TE 2 , 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 in  FIG. 14 , and the examples shown in  FIG. 9  and  FIG. 10  can be used. 
     During processing by the processor, the sheet manufacturing apparatus  100  according to the second embodiment of the invention drives the drum  41  at a speed V 11  to discharge material from the drum  41 . When the sheet manufacturing apparatus  100  starts from a state in which the drum  41  is stopped, a sieve startup operation including a state in which the drum  41  operates at a different speed than the third speed during the speed adjustment period TE 2  is executed. The sieve startup operation is an operation of controlling the speed of the drum  41  according to the speed conditions set in the setup process ( FIG. 12 ) as shown in  FIG. 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 drum  41 , and the speed of the mesh belt  46 , in the period when the amount of first screened material MC discharged from the drum  41  increases easily. As a result, variation in the thickness of the first web W 1  can be more effectively suppressed. 
     3. Embodiment 3 
     A third embodiment of the invention is described next. 
     The first and second embodiments describe adjusting the speed VA of the mesh belt  46  and/or the speed VB of the drum  41  in the startup operation by the drive controller  152  controlling the first belt motor  47   b  and/or first sieve motor  40   a.    
     In the third embodiment, the drive controller  152  adjusts the speed VD of the drum  61  by controlling the second belt motor  74   b  and/or second sieve motor  60   a  in the startup operation. 
     More specifically, the controller  150  applies the control of the first belt motor  47   b  described in the first embodiment to controlling the second belt motor  74   b . The controller  150  also applies control of the first sieve motor  40   a  and first belt motor  47   b  described in the second embodiment to controlling the second sieve motor  60   a  and second belt motor  74   b.    
     In the third embodiment, the drum  61  is an example of a sieve, the second sieve motor  60   a  is an example of a sieve driver, the second web former  70  is an example of an accumulator, and the mesh belt  72  is an example of a receiver. The second belt motor  74   b  is also an example of a driver, and the second temperature/humidity detector  333  is an example of a humidity detector. 
     3-1. Second Web Forming Conditions 
     The conditions for forming the second web W 2  formed by the second web former  70  are described below with reference to  FIG. 3 . 
     The thickness of the second web W 2  is determined by the amount of mixture MX, which is the material supplied to the mesh belt  72 , and the amount of movement of the mesh belt  72  per unit time. The amount of movement of the mesh belt  72  per unit time is speed VC. 
     One factor determining the amount of mixture MX supplied to the mesh belt  72 , that is, the amount of mixture MX passing through the openings  61   a , is speed VD. As speed VD increases, the mixture MX is more quickly detangled in the drum  61 , and the mixture MX passes more easily through the openings  61   a . In addition, the greater the speed VD, the more easily the mixture MX passes the openings  61   a . Therefore, the amount of mixture MX passing the openings  61   a  increases as the speed VD increases. 
     The amount of mixture MX passing the openings  61   a  changes when the drum  61  starts operating from a stop. Because rotation of the drum  61  produces friction between the fibers of the mixture MX inside the drum  61 , 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 openings  61   a . On the other hand, when the drum  61  is stopped, the charge of the charged mixture MX is discharged, and clumps of fiber in the mixture MX break apart. Therefore, when the drum  61  starts turning from a stop, that is, when the drum  61  starts operating, that is, during startup, the amount of mixture MX passing the openings  61   a  temporarily increases. 
     The amount of mixture MX passing the openings  61   a  is also affected by the humidity in the drum  61 . Humidity as used here can be referred to as relative humidity (RH). If the humidity inside the drum  61  is low, the mixture MX becomes charged and fibers clump easily. Therefore, the lower the humidity inside the drum  61 , and the drum  61  starts turning from a stop, that is, during startup, the amount of mixture MX passing the holes  61   a  temporarily increases. 
     The amount of mixture MX passing the openings  61   a  also varies according to the length of the fiber in the mixture MX. Short fibers pass through the openings  61   a  easily. Therefore, the shorter the fibers in the mixture MX, the greater the amount of mixture MX that passes the openings  61   a.    
     In other words, the greatest factor determining the amount of mixture MX supplied from the drum  61  to the mesh belt  72  is the speed VD of the drum  61 . Factors that change the amount of mixture MX include whether or not the drum  61  is starting up, the humidity inside the drum  61 , and the length of fiber in the mixture MX. 
     If the thickness of the second web W 2  varies, the amount of material supplied to processes downstream from the second web former  70  may vary, affecting the quality of the sheets S manufactured by the sheet manufacturing apparatus  100 . 
     The controller  150  of the sheet manufacturing apparatus  100  therefore executes a control process that suppresses variation in the thickness of the second web W 2 . 
     To execute control related to the thickness of the second web W 2 , the controller  110  can acquire the detection value output from the second thickness detector  334 . As shown in  FIG. 4 , the controller  110  can also control the speed of the second sieve motor  60   a  and second belt motor  74   b.    
     3-2. Sheet Manufacturing Apparatus Operation 
     The controller  150  first executes the operation shown in  FIG. 6  by drive controller  152 . In the setup process of step ST 1 , the controller  150  configures settings related to the operation of the second belt motor  74   b . In this case, in the setup process shown in  FIG. 7 , the controller  150  sets the speed VC of the mesh belt  72  according 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 ST 1 , the controller  150  also configures settings related to the operation of the second sieve motor  60   a  and second belt motor  74   b . In this case, the controller  150  sets the first to fifth speed conditions for speed VD of the drum  61  and speed VC of the mesh belt  72  in the setup process in  FIG. 12 . 
     The controller  150  applies the setup processes in  FIG. 7  and  FIG. 12  to 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 drum  61  starts operating, and include a target speed for the second sieve motor  60   a , and the time or the acceleration rate of the second sieve motor  60   a  to the target speed. 
     Control related to starting speed VC may use the patterns shown in  FIG. 9  to  FIG. 11  and  FIG. 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 detector  332 . In addition, the data shown in  FIG. 13  may 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 detector  331 . 
     The target speed V 1  of speed VC may be the same as target speed V 1  of 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 drum  61  may be used. This also applies to the first to fifth speed conditions set for speed VD. 
     In the third embodiment, the controller  150  suppresses variation in the thickness of the second web W 2  by controlling the speed VC of the mesh belt  72  when the amount of mixture MX dropping from the drum  61  to the mesh belt  72  increases temporarily. As a result, in the sheet S manufacturing process of the sheet manufacturing apparatus  100 , the amount of mixture MX supplied to processes downstream from the second web former  70  can 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 apparatus  100  applying the fiber processing device and control method of a fiber processing device according to the third embodiment of the invention has a drum  61  that sieves mixture MX, which is material containing fiber, and a second web former  70  for accumulating mixture MX discharged from the drum  61 . The sheet manufacturing apparatus  100  also has the parts of a processor that processes the second web W 2  accumulated on the mesh belt  72 , that is, the mixture MX. The processor may include any process downstream from the second web former  70 , such as the sheet former  80  or sheet cutter  90 . 
     During processing by the processor, the sheet manufacturing apparatus  100  operates the mesh belt  72  at a target speed V 1 . When starting with the  61  stopped, the sheet manufacturing apparatus  100  executes a startup operation including a state in which the mesh belt  72  travels faster than the target speed V 1  during a speed adjustment period after the drum  61  starts. As a result, even if the amount of mixture MX discharged from the drum  61  increases temporarily, an increase in the thickness of the second web W 2  accumulated on the second web former  70  can be suppressed. The amount of mixture MX supplied to processes downstream from the second web former  70  while the sheet manufacturing apparatus  100  manufactures 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 apparatus  100  also maintains a state in which the mesh belt  72  operates at a higher speed than the target speed V 1 . As a result, because speed VC is held at a speed faster than the target speed V 1  during the period when the amount of mixture MX falling from the drum  61  increases easily, variation in the thickness of the second web W 2  due to variation in the amount of mixture MX can be effectively suppressed. 
     The second web former  70  has a mesh belt  72  on which the mixture MX can be accumulated in a sheet, and the mesh belt  72  moves in a circulating path defined by the tension rollers  74 . Therefore, by setting the speed VC at which the mesh belt  72  moves faster than the target speed V 1 , variation in the thickness of the second web W 2  accumulated on the mesh belt  72  can be suppressed. 
     During processing by the processor, the sheet manufacturing apparatus  100  drives the mesh belt  72  at a target speed V 1 , and in the speed adjustment period, maintains the operating speed of the mesh belt  72  at a second speed that is faster than the target speed V 1 . This configuration can effectively suppress variation in the thickness of the second web W 2  due to temporary variation in the amount of mixture MX in the speed adjustment period because the mesh belt  72  operates at a higher speed than the target speed V 1  for the speed VC when making sheets S. 
     When the sheet manufacturing apparatus  100  starts from a state in which the drum  61  is stopped, the operating speed of the mesh belt  72  may accelerate to a higher speed than the target speed V 1 , and in a second period after acceleration ends, the mesh belt  72  is held at an operating speed greater than the target speed V 1 . Because the speed VC exceeds the target speed V 1  during the time when the amount of mixture MX dropping from the drum  61  increases easily, this configuration can effectively suppress variation in the thickness of the second web W 2  due to variations in the amount of mixture MX. 
     When starting from a state in which the drum  61  is stopped, the sheet manufacturing apparatus  100  may execute the startup operation when there is mixture MX inside the drum  61 . Because speed VC thus exceeds the target speed V 1  during the time when the amount of mixture MX dropping from the drum  61  increases easily, this configuration can effectively suppress variation in the thickness of the second web W 2  due to variation in the amount of mixture MX. By executing the normal startup sequence when the amount of mixture MX dropping from the drum  61  does not vary easily, a drop in productivity manufacturing sheets S can be prevented. 
     The drum  61  is a round cylinder having openings formed in the outside surface of the drum  61 , and configured to rotate on the axis of the cylinder. When the drum  61  starts turning with m×m inside the drum  61 , the amount of mixture MX that drops onto the mesh belt  72  when operation starts can fluctuate easily. Variation in the thickness of the second web W 2  due to variation in the amount of mixture MX can be suppressed in this configuration because a period in which the mesh belt  72  moves at a speed greater than the target speed V 1  is maintained by the controller  150 . 
     Control of the first sieve motor  40   a  as described in the second embodiment can also be applied to controlling the second sieve motor  60   a . More specifically, control of the speed of the drum  41  can be applied to controlling the speed of drum  61 . When the sheet manufacturing apparatus  100  starts from a state in which the drum  61  is stopped, a sieve startup operation including a state in the speed adjustment period in which the drum  61  operates at a different speed than the speed V 11  during 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 belt  72 , and the speed of the mesh belt  72 , can be adjusted in the period in which the amount of mixture MX falling from the drum  61  may increase easily. As a result, variation in the thickness of the second web W 2  can 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 controller  150  applying the setup process in  FIG. 7  to controlling the speed of the mesh belt  46 , and starting the mesh belt  46  and drum  41  in step ST 7  based on the speed conditions that are set. 
     The foregoing second embodiment describes the controller  150  executing the setup process shown in  FIG. 12 , and starting the mesh belt  46  and drum  41  in step ST 7  based on the speed conditions that are set. 
     The foregoing third embodiment describes the controller  150  executing the setup processes in  FIG. 7  and  FIG. 12  to control the speed of the mesh belt  72 , or control the speed of the mesh belt  72  and the drum  61 . 
     The invention is not so limited, however, and the controller  150  may execute the setup process in  FIG. 7  to control the speed of both mesh belt  46  and mesh belt  72 . The controller  150  may also execute the setup process of  FIG. 12  on each of drums  41 ,  61  and mesh belts  46 ,  72 . In other words, the controller  150  may apply the control method of the invention to the speed VA of the mesh belt  46 , the speed VB of the drum  41 , the speed VC of mesh belt  72 , and speed VD of drum  61 . In this case, the controller  150  also controls the first sieve motor  40   a , second sieve motor  60   a , first belt motor  47   b , and second belt motor  74   b.    
     The foregoing embodiments describe the mesh belt  46  and the mesh belt  72  as 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 drums  41 ,  61 . For example, a cylindrical sieve with openings may be used as the sieve. 
     The location of the first temperature/humidity detector  323  in the foregoing embodiments is also not limited to inside the drum  41 , and may be inside the housing  43 , for example. Likewise, the second temperature/humidity detector  333  is not limited to being disposed inside the drum  61 , and may be located inside the housing  63 . 
     A temperature sensor or a sensor for detecting the moisture content of the feedstock material MA may be disposed to the feedstock feeder  10 , in which case the controller  150  can estimate the humidity inside the drum  41  and inside the drum  61  based on the detected temperature and/or moisture content of the feedstock material MA. A temperature/humidity sensor may also be disposed in conduit  2  and conduit  3 , and configured to detect the temperature and/or humidity before and after the defibrator  20 . In this case, the controller  150  can estimate the humidity inside the drum  41  and inside the drum  61  based on the change in the detected temperature and/or moisture content before and after processing by the defibrator  20 . A temperature/humidity sensor may also be disposed to detect the temperature and/or humidity inside the housing of the sheet manufacturing apparatus  100 . □ 
     When the invention is applied to the air-laying device  60  and second web former  70  in 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 classifier  40 . This classifier may be a cyclone classifier, elbow-jet classifier, or eddy classifier, for example. 
     The specific configurations whereby the drive controller  152  controls the speed of the first sieve motor  40   a , second sieve motor second sieve motor  60   a , first belt motor  47   b , and second belt motor  74   b  are 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 apparatus  100  is 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 apparatus  100  that 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.□ 
     The invention being thus described, it will be obvious that it may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.