Patent Publication Number: US-9890500-B2

Title: Sheet manufacturing apparatus

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a sheet manufacturing apparatus. 
     2. Related Art 
     In the related art, as a sheet manufacturing apparatus, a so-called wet type sheet manufacturing apparatus is employed in which a raw material containing fibers is fed into water, is disaggregated mainly by a mechanical action, and is repulped. Such a wet type sheet manufacturing apparatus is large in size since the apparatus requires a large amount of water. Furthermore, it takes time and effort for maintenance of water treatment facilities, and energy for a drying process is increased. 
     Therefore, for size reduction and energy saving, a dry type sheet manufacturing apparatus in which as little water as possible is used has been proposed. For example, a technique, in which pieces of paper are defibrated into fibers by a dry type defibration machine, deinking of fibers is performed in a cyclone, the deinked fibers pass through a screen having small holes of a forming drum surface, are sucked by a suction device, are deposited on a mesh belt, and then paper is formed, is disclosed in JP-A-2012-144819. 
     However, in the sheet manufacturing apparatus described above, if fibers are supplied to a forming drum unit by airflow, the amount of fibers deposited on the mesh belt becomes uneven and a grammage of a sheet to be manufactured may become uneven by the airflow being disturbed. Furthermore, the inside of a housing unit accommodating the drum unit has a negative pressure and an intake air amount from a portion between the mesh belt and the housing unit may be increased due to suction of the suction device (suction unit). Thus, the amount of fibers deposited on the mesh belt becomes uneven and the grammage of the sheet to be manufactured may become uneven. 
     SUMMARY 
     An advantage of some aspects of the invention is to provide a sheet manufacturing apparatus capable of manufacturing a sheet with high uniformity in grammage. 
     The invention can be realized in the following aspects or application examples. 
     According to an aspect of the invention, there is provided a sheet manufacturing apparatus including a rotatable drum unit in which a plurality of openings are formed; a web forming unit that forms a web by using a material containing fibers passing through the openings of the drum unit; a housing unit that covers at least a portion of the drum unit in which the openings are formed; a material supply port that is provided to supply the material containing fibers in a direction along a rotational axis of the drum unit to the inside of the drum unit by airflow; and an air intake port that is provided to supply air, that does not contain the material, in the direction along the rotational axis of the drum unit to the inside of the drum unit. The web forming unit includes a mesh belt on which the material containing fibers is deposited and a suction unit that sucks the material containing fibers onto the mesh belt. 
     In this case, it is possible to deposit a defibrated material having high uniformity on the mesh belt and it is possible to manufacture a sheet having high uniformity in grammage. 
     In the sheet manufacturing apparatus, the air intake port may be provided on a periphery of the material supply port. 
     In this case, it is possible to further reliably suppress that airflow is disturbed on the inside of the drum unit. 
     The sheet manufacturing apparatus may further include a transport pipe that has an inner surface forming the material supply port, in which a through hole greater than the material supply port in size may be provided in the housing unit, and the air intake port may be a gap formed between a surface of the housing unit forming the through hole and an outer surface of the transport pipe. 
     In this case, it is possible to further reliably suppress that airflow is disturbed on the inside of the drum unit. 
     In the sheet manufacturing apparatus, the air intake port may be provided further on the mesh belt side than the material supply port. 
     In this case, it is possible to further reliably suppress that the web deposited on the mesh belt is disturbed. 
     In the sheet manufacturing apparatus, the air intake port may be provided in a position nearer to an end portion of the housing unit on a downstream side in a transport direction of the web than the material supply port. 
     In this case, it is possible to further reliably suppress that the web deposited on the mesh belt is disturbed. 
     Furthermore, according to another aspect of the invention, there is provided a sheet manufacturing apparatus including a rotatable drum unit in which a plurality of openings are formed; a web forming unit that forms a web by using a material containing fibers passing through the openings of the drum unit; a housing unit that covers at least a portion of the drum unit in which the openings are formed; a material supply port that is provided to supply the material containing fibers to the inside of the drum unit by airflow; and an air intake port that is provided to supply air that does not contain the material from the outside of the housing unit to the inside of the drum unit with the inside of the housing unit having a negative pressure. 
     In this case, it is possible to suppress that airflow is disturbed on the inside of the drum unit and to form the web while depositing the defibrated material with high uniformity. In addition, it is possible to manufacture a sheet having high uniformity in grammage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a diagram schematically illustrating a sheet manufacturing apparatus according to an embodiment. 
         FIG. 2  is a plan view schematically illustrating the sheet manufacturing apparatus according to the embodiment. 
         FIG. 3  is a sectional view schematically illustrating the sheet manufacturing apparatus according to the embodiment. 
         FIG. 4  is a sectional view schematically illustrating the sheet manufacturing apparatus according to the embodiment. 
         FIG. 5  is a perspective view schematically illustrating the sheet manufacturing apparatus according to the embodiment. 
         FIG. 6  is a graph illustrating a grammage of a sheet with respect to a position of the sheet in a width direction thereof. 
         FIG. 7  is a sectional view schematically illustrating a sheet manufacturing apparatus according to a first modification example of the embodiment. 
         FIG. 8  is a sectional view schematically illustrating a sheet manufacturing apparatus according to a second modification example of the embodiment. 
         FIG. 9  is a sectional view schematically illustrating a sheet manufacturing apparatus according to a third modification example of the embodiment. 
         FIG. 10  is a sectional view schematically illustrating a sheet manufacturing apparatus according to a fourth modification example of the embodiment. 
         FIG. 11  is a sectional view schematically illustrating the sheet manufacturing apparatus according to the fourth modification example of the embodiment. 
         FIG. 12  is a sectional view schematically illustrating a sheet manufacturing apparatus according to a fifth modification example of the embodiment. 
         FIG. 13  is a sectional view schematically illustrating a sheet manufacturing apparatus according to a sixth modification example of the embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. Moreover, the embodiments described below do not unduly limit the content of the invention described in the aspects. Furthermore, not all configurations described below are essential requirements for the invention. 
     1. Sheet Manufacturing Apparatus 
     1.1. Configuration 
     First, a sheet manufacturing apparatus according to an embodiment will be described with reference to the drawings.  FIG. 1  is a diagram schematically illustrating a sheet manufacturing apparatus  100  of the embodiment. 
     As illustrated in  FIG. 1 , the sheet manufacturing apparatus  100  includes a supply unit  10 , a manufacturing unit  102 , and a control unit  104 . The manufacturing unit  102  manufactures a sheet. The manufacturing unit  102  has a crushing unit  12 , a defibrating unit  20 , a screening unit  40 , a first web forming unit  45 , a rotary body  49 , a mixing unit  50 , a deposition unit  60 , a second web forming unit  70 , a sheet forming unit  80 , and a cutting unit  90 . 
     The supply unit  10  supplies a raw material to the crushing unit  12 . For example, the supply unit  10  is an automatic feeding unit for continuously feeding the raw material to the crushing unit  12 . The raw material supplied by the supply unit  10  contains, for example, used papers and fibers such as pulp sheets. 
     The crushing unit  12  cuts and shreds the raw material supplied by the supply unit  10  in air. Shapes and sizes of shredded pieces are, for example, squares of several cm. In the illustrated example, the crushing unit  12  has crushing blades  14  and the fed raw material can be cut by the crushing blades  14 . For example, as the crushing unit  12 , a shredder is used. The raw material that is cut by the crushing unit  12  is received by a hopper  1  and then is transferred (transported) to the defibrating unit  20  through a pipe  2 . 
     The defibrating unit  20  defibrates the raw material that is cut by the crushing unit  12 . Here, “defibrating” means that the raw material (defibration object) formed by binding a plurality of fibers is untangled to untangled fibers one by one. The defibrating unit  20  also has a function of separating a material such as resin particles, ink, toner, and a blur-preventing agent, attached to the raw material from the fibers. 
     A material passing through the defibrating unit  20  is referred to as “defibrated material”. In addition to the untangled defibrated material fibers, the “defibrated material” may contain the resin (resin for binding a plurality of fibers to each other) particles, a coloring material such as ink and toner, the blur-preventing agent, and additives such as a paper strengthening agent separated from the fibers when untangling the fibers. A shape of the untangled defibrated material is a string shape or a ribbon shape. The untangled defibrated material may be present in a state of not being intertwined with other untangled fibers (independent state) or may be present in a state of being a lump shape by intertwining with other untangled defibrated materials (a so-called state of forming “lumps”). 
     The defibrating unit  20  performs dry type defibration in the atmosphere (in air). Specifically, as the defibrating unit  20 , an impeller mill is used. The defibrating unit  20  has a function of sucking the raw material and generating airflow so as to discharge the defibrated material. Thus, the defibrating unit  20  sucks the raw material from an introduction port  22  together with airflow by the airflow generated by the defibrating unit  20 , performs a defibrating process, and then the defibrated material can be transported to a discharge port  24 . The defibrated material passing through the defibrating unit  20  is transferred to the screening unit  40  through the pipe  3 . Moreover, as the airflow for transporting the defibrated material from the defibrating unit  20  to the screening unit  40 , airflow generated by the defibrating unit  20  may be used. In addition, an airflow generation device such as a blower is provided and airflow thereof may be used. 
     The screening unit  40  introduces the defibrated material that is defibrated by the defibrating unit  20  and screens the defibrated material by lengths of the fibers. As the screening unit  40 , for example, a sieve (screen) is used. The screening unit  40  has a net (filter and screen) and can separate the defibrated material into fibers or particles (those passing through the net, first screened matter) smaller than a size of a mesh of the net and fibers, the non-defibrated pieces, or lumps (those that do not pass through the net, second screened matter) which is greater than the mesh of the net in size. For example, the first screened matter is transferred to the mixing unit  50  through a pipe  7 . The second screened matter is returned to the defibrating unit  20  through a pipe  8 . Specifically, the screening unit  40  is a cylindrical sieve that is driven to be rotated by a motor. As the net of the screening unit  40 , for example, wire mesh, expanded metal that is formed by extending a metal plate in which cut lines are run, and a perforated metal in which holes are formed in a metal plate by a press machine are used. 
     A first web forming unit  45  transports the first screened matter passing through the screening unit  40  to the mixing unit  50 . The first web forming unit  45  includes a mesh belt  46 , a tension roller  47 , and a suction unit (suction mechanism)  48 . 
     The suction unit  48  can suck the first screened matter that is scattered in the air by passing through an opening (opening of the net) of the screening unit  40  on the mesh belt  46 . The first screened matter is deposited on the moving mesh belt  46  and forms a web V. Basic configurations of the mesh belt  46 , the tension roller  47 , and the suction unit  48  are similar to those of a mesh belt  72 , a tension roller  74 , and a suction unit  76  of the second web forming unit  70  described below. 
     The web V is formed in a state of being soft and inflated containing a lot of air by going through the screening unit  40  and the first web forming unit  45 . The web V deposited in the mesh belt  46  is fed into the pipe  7  and is transported to the mixing unit  50 . 
     The rotary body  49  can cut the web V before the web V is transported to the mixing unit  50 . In the illustrated example, the rotary body  49  has a base unit  49   a  and protrusion units  49   b  protruding from the base unit  49   a . For example, the protrusion units  49   b  have a plate shape. In the illustrated example, four protrusion units  49   b  are provided and the four protrusion units  49   b  are provided at equal intervals. The base unit  49   a  rotates in a direction R and thereby the protrusion units  49   b  can rotate around the base unit  49   a  as an axis. It is possible to reduce variation of the amount of the defibrated material per unit time, for example, supplied to the deposition unit  60  by cutting the web V by the rotary body  49 . 
     The rotary body  49  is provided in the vicinity of the first web forming unit  45 . In the illustrated example, the rotary body  49  is provided in the vicinity (next to the tension roller  47   a ) of a tension roller  47   a  positioned on a downstream side in a path of the web V. The rotary body  49  is provided in a position in which the protrusion units  49   b  can come into contact with the web V and do not come into contact with the mesh belt  46  in which the web V is deposited. Thus, it is possible to suppress that the mesh belt  46  is worn (damaged) by the protrusion units  49   b . The shortest distance between the protrusion unit  49   b  and the mesh belt  46  is, for example, 0.05 mm or more and 0.5 mm or less. 
     The mixing unit  50  mixes the first screened matter (the first screened matter transported by the first web forming unit  45 ) passing through the screening unit  40  and additives containing resin. The mixing unit  50  has an additive supply unit  52 , a pipe  54  that transports the first screened matter and the additives, and a blower  56 . In the illustrated example, the additives are supplied from the additive supply unit  52  to the pipe  54  through a hopper  9 . The pipe  54  is connected to the pipe  7 . 
     In the mixing unit  50 , airflow is generated by the blower  56  and in the pipe  54 , it is possible to transport the first screened matter and the additives while being mixed. Moreover, a mechanism for mixing the first screened matter and the additives is not specifically limited, may be one which stirs the first screened matter and the additives by blades rotating at a high speed or may be one which uses rotation of a container as a V type mixer. 
     As the additive supply unit  52 , a screw feeder as illustrated in  FIG. 1 , a disk feeder (not illustrated), and the like are used. The additives supplied from the additive supply unit  52  contain resin for binding a plurality of fibers. At the time resin is supplied, the plurality of fibers are not bound. Resin is melted when passing through the sheet forming unit  80  and binds the plurality of fibers. 
     Resin supplied from the additive supply unit  52  is thermoplastic resin or thermosetting resin, and for example, is AS resin, ABS resin, polypropylene, polyethylene, polyvinyl chloride, polystyrene, acrylic resin, polyester resin, polyethylene terephthalate, polyphenylene ether, polybutylene terephthalate, nylon, polyamide, polycarbonate, polyacetal, polyphenylene sulfide, polyether ether ketone, and the like. These resins may be used singly or by being appropriately mixed. The additives supplied from the additive supply unit  52  may be fiber or powder. 
     Moreover, the additives supplied from the additive supply unit  52  may contain coloring agents for coloring fibers, a coagulation preventing agent for preventing coagulation of fibers, and a flame retardant for deflocculating material for fibers are unlikely to burn depending on a type of the manufacturing sheet in addition to resin binding fibers. A mixture (mixture of the first screened matter and the additives) passing through the mixing unit  50  is transferred to the deposition unit  60  through the pipe  54 . 
     The deposition unit  60  allows the mixture passing through the mixing unit  50  to be introduced, and entangled defibrated material (fibers) to be loosened, and to be dropped while dispersing in the air. Furthermore, the deposition unit  60  allows entangled resins to be loosened if resins of the additives supplied from the additive supply unit  52  are fibers. Thus, the deposition unit  60  can deposit the mixture in the second web forming unit  70  with high uniformity. 
     As the deposition unit  60 , a rotating cylindrical sieve is used. The deposition unit  60  has a net and allows fibers or particles (passing through the net) contained in the mixture passing through the mixing unit  50 , which are smaller than the size of a mesh of the net, to be dropped. A configuration of the deposition unit  60  is, for example, the same as the configuration of the screening unit  40 . 
     Moreover, the “sieve” of the deposition unit  60  may not have a function of selecting a particular object. That is, the “sieve” that is used for the deposition unit  60  means a sieve having a net and the deposition unit  60  may allow all mixtures introduced into the deposition unit  60  to be dropped. 
     The second web forming unit  70  forms the web W by depositing a passing object passing through the deposition unit  60 . The second web forming unit  70  has, for example, the mesh belt  72 , the tension roller  74 , and the suction unit  76 . 
     The mesh belt  72  deposits the passing object passing through an opening (opening of the net) of the deposition unit  60  while moving. The mesh belt  72  is stretched by the tension roller  74  and has a configuration through which the passing object is unlikely to pass and air is likely to pass. The mesh belt  72  is moved by rotation of the tension roller  74 . The passing object passing through the deposition unit  60  is continuously dropped and deposited while the mesh belt  72  continuously moves and thereby the web W is formed on the mesh belt  72 . The mesh belt  72  is, for example, metal, resin, fabric, nonwoven fabric, and the like. 
     The suction unit  76  is provided on a lower side (side opposite to the deposition unit  60  side) of the mesh belt  72 . The suction unit  76  can generate airflow (airflow from the deposition unit  60  to the mesh belt  72 ) to the lower side. The mixture dispersed in the air by the deposition unit  60  can be sucked on the mesh belt  72  by the suction unit  76 . Thus, it is possible to increase a discharge speed from the deposition unit  60 . Furthermore, it is possible to form down flow in a fall path of the mixture by the suction unit  76  and it is possible to prevent falling defibrated material and a mixture from being entangled. 
     As described above, a web W in a state of being soft and inflated containing a lot of air is formed by going through the deposition unit  60  and the second web forming unit  70  (web forming process). The web W deposited in the mesh belt  72  is transported to the sheet forming unit  80 . 
     Moreover, in the illustrated example, a moisture-adjusting unit  78  adjusting moisture of the web W is provided. The moisture-adjusting unit  78  can adjust an amount ratio of the web W and water by adding water or steam with respect to the web W. 
     The sheet forming unit  80  forms a sheet S by pressurizing and heating the web W deposited in the mesh belt  72 . In the sheet forming unit  80 , it is possible to bind the plurality of fibers in the mixture through the additives (resin) to each other by adding heat to the mixture of the defibrated material and the additives mixed in the web W. 
     The sheet forming unit  80  includes a pressurizing unit  82  that pressurizes the web W and a heating unit  84  that heats the web W pressurized by the pressurizing unit  82 . The pressurizing unit  82  is configured of a pair of calendar rollers  85  and applies pressure to the web W. A thickness of the web W is reduced and a density of the web W is increased by applying the pressure. As the heating unit  84 , for example, a heating roller (heater roller), a heat press molding machine, a hot plate, a hot air blower, an infrared heater, and a flash fixer are used. In the illustrated example, the heating unit  84  is configured of a pair of heating rollers  86 . The heating unit  84  is configured of the heating rollers  86  and thereby it is possible to form the sheet S while continuously transporting the web W compared to a case where the heating unit  84  is configured as a plate-shaped press device (flat plate press device). Here, the calendar rollers  85  (pressurizing unit  82 ) can apply a pressure higher than a pressure applied to the web W by the heating rollers  86  (heating unit  84 ) to the web W. Moreover, the number of the calendar rollers  85  and the heating rollers  86  is not specifically limited. 
     The cutting unit  90  cuts the sheet S formed by the sheet forming unit  80 . In the illustrated example, the cutting unit  90  has a first cutting unit  92  that cuts the sheet S in a direction orthogonal to the transport direction of the sheet S and a second cutting unit  94  that cuts the sheet S in a direction parallel to the transport direction. For example, the second cutting unit  94  cuts the sheet S passing through the first cutting unit  92 . 
     As described above, a cut sheet S of a predetermined size is formed. The cut sheet S that is cut is discharged to a discharge unit  96 . 
     1.2. Housing Unit, Material Supply Port, and Air Intake Port 
     The sheet manufacturing apparatus  100  further has a housing unit  110 , a material supply port  120 , and an air intake port  130 . Hereinafter, the housing unit  110 , the material supply port  120 , and the air intake port  130  will be described in detail.  FIG. 2  is a plan view schematically illustrating the vicinity of the housing unit  110 .  FIG. 3  is a sectional view that is taken along line III-III of  FIG. 2  schematically illustrating the vicinity of the housing unit  110 .  FIG. 4  is a sectional view that is taken along line IV-IV of  FIG. 2  schematically illustrating the vicinity of the housing unit  110 .  FIG. 5  is a perspective view schematically illustrating the vicinity of the housing unit  110 . 
     The deposition unit  60  is a cylindrical drum (hereinafter, the deposition unit is also referred to as a drum unit) formed to be rotatable around a rotational axis Q. A plurality of openings  60   a  are formed in a peripheral surface of the drum unit (deposition unit)  60 . The deposition unit  60  allows fibers (defibrated material) passing through the openings  60   a  to be deposited on the mesh belt  72 . That is, the defibrated material is deposited in the mesh belt  72 . The second web forming unit  70  forms the web W by using the defibrated material passing through the openings  60   a  of the drum unit  60 . A size, a shape, and the number of the openings  60   a  are not specifically limited. Moreover, for the sake of convenience, the openings  60   a  are largely illustrated with respect to the drum unit  60  in FIGS.  3 ,  10 ,  12 , and  13 . 
     The housing unit  110  covers a portion (outer peripheral surface  60   b  on which the openings  60   a  are formed) in which at least the openings  60   a  of the drum unit  60  are formed through gaps. In the example illustrated in  FIGS. 3 and 4 , the housing unit  110  has an opposite wall unit  111  having an inner surface opposite to the outer peripheral surface  60   b , a first side wall unit  112   a , and a second side wall unit  112   b  which are connected to the opposite wall unit  111  and cover the drum unit  60  in a direction of the rotational axis Q (direction in which the rotational axis Q extends), and accommodates the drum unit  60 . 
     As illustrated in  FIG. 3 , concave units  114  are provided on inner surfaces of the side wall units  112   a  and  112   b  of the housing unit  110 . Pile seals  140  are provided in the concave units  114 . The drum unit  60  is supplied to be rotatable with a predetermined interval with the housing unit  110  through the pile seals  140 . The pile seal  140  is, for example, configured of a brush where densely thin hairs are planted on a surface of a base unit. 
     The pipe (transport pipe)  54  is connected to the side wall units  112   a  and  112   b  of the housing unit  110 . The transport pipe  54  transports (supplies) the defibrated material to the inside of the drum unit  60 . As illustrated in  FIG. 2 , the transport pipe  54  is branched into a first portion  54   a  and a second portion  54   b  in a branch unit  54   c , the first portion  54   a  is connected to the first side wall unit  112   a , and the second portion  54   b  is connected to the second side wall unit  112   b . Thus, it is possible to supply the defibrated material from both sides of the drum unit  60  to the inside of the drum unit  60 . In the illustrated example, the transport pipe  54  is integrally provided with the housing unit  110 . Moreover, connection between the deposition unit  60  and the transport pipe  54 , and connection between the screening unit  40  and the pipes  3  and  8  are simplified in  FIG. 1 . 
     The material supply ports  120 , which supply the defibrated material in the direction of the rotational axis Q to the inside of the drum unit  60  by airflow A 1 , are provided in the side wall units  112   a  and  112   b  of the housing unit  110 . The material supply port  120  is a through hole extending in the direction of the rotational axis Q. A direction of the airflow A 1  within the material supply port  120  is the direction of the rotational axis Q. In the illustrated example, one material supply port  120  is provided in each of the side wall units  112   a  and  112   b  of the housing unit  110 . As illustrated in  FIG. 4 , the material supply port  120  is provided in a position overlapping the rotational axis Q when viewed in the direction of the rotational axis Q. The material supply port  120  provided in the first side wall unit  112   a  communicates with the inside of the first portion  54   a  of the transport pipe  54 . The material supply port  120  provided in the second side wall unit  112   b  communicates with the inside of the second portion  54   b  of the transport pipe  54 . 
     The air intake ports  130 , which supply air (for example, air on the outside of the housing unit  110 ) that does not contain the defibrated material (material) in the direction of the rotational axis Q of the drum unit  60  to the inside of the drum unit  60  by airflow A 2 , are provided in the housing unit  110 . The air intake port  130  is a through hole extending in the direction of the rotational axis Q. For example, a direction of the airflow A 2  generated within the air intake port  130  is the direction of the rotational axis Q. In the illustrated example, one air intake port  130  is provided in each of the side wall units  112   a  and  112   b  of the housing unit  110 . The air intake port  130  is provided at a distance from the material supply port  120 . As illustrated in  FIG. 4 , the air intake port  130  is provided in a position overlapping the inside of the drum unit  60  when viewed in the direction of the rotational axis Q. For example, the air intake port  130  communicates with the outside of the housing unit  110  and the inside of the drum unit  60 . 
     For example, the air intake port  130  is provided on a side opposite (position far from the mesh belt  72 ) to the mesh belt  72  side further than the material supply port  120 . That is, a distance between the air intake port  130  and the mesh belt  72  is greater than a distance between the material supply port  120  and the mesh belt  72 . 
     Moreover, the airflow A 1  is generated by the blower  56 . The airflow A 2  is generated by natural air intake by a difference between a first flow rate (in the illustrated example, a total flow rate from two material supply ports  120 ) supplied (pushed) from the material supply ports  120  to the inside of the housing unit  110  by the blower  56  and a second flow rate discharged to the outside of the housing unit  110  by the suction unit  76 . That is, air on the inside of the housing unit  110  is discharged, the inside of the housing unit  110  is a negative pressure, and thereby air on the outside of the housing unit  110  is supplied from the air intake port  130  to the inside of the drum unit  60  (housing unit  110 ). The suction device (suction unit)  76  generates airflow vertically downward and sucks the defibrated material on the mesh belt  72 . 
     For example, if the first flow rate is 0.8 m 3 /min and the second flow rate is 1.5 m 3 /min, a third flow rate (in the illustrated example, a total flow rate from two air intake ports  130 ) supplied from the air intake port  130  to the inside of the housing unit  110  is 0.7 m 3 /min. If the first flow rate is 0.8 m 3 /min and the second flow rate is 3 m 3 /min, the third flow rate is 2.2 m 3 /min. As described above, in the sheet manufacturing apparatus  100 , it is possible to suppress that the first flow rate is changed depending on a change in the second flow rate by providing the air intake port  130 . That is, it is possible to independently change the first flow rate and the second flow rate. For example, in a case where the air intake port is not provided, if the second flow rate is changed, the first flow rate is also changed. 
     For example, the third flow rate is 20% or more of the second flow rate and is preferably 50% or more of the second flow rate. Moreover, the second flow rate is greater than the first flow rate in size and thereby it is possible to suppress that air on the inside of the housing unit  110  is leaked from the material supply port  120  to the outside. 
     The housing unit  110  is provided with a predetermined interval with the mesh belt  72  through pile seals  142  and  144 . In the example illustrated in  FIG. 5 , the pile seals  142  and  144  have rectangular parallelepiped (substantially rectangular parallelepiped) shapes. The pile seals  142  and  144  are, for example, configured of a brush where densely thin hairs are planted on a surface of a base unit. The opposite wall unit  111  of the housing unit  110  is connected to seal rollers  146  through the pile seals  142 . For example, the seal roller  146  is a metal roller, is biased by its own weight thereof and a biasing member such as a spring, and comes into contact with the mesh belt  72  in a state where the web W is not deposited on the mesh belt  72 . The side wall units  112   a  and  112   b  of the housing unit  110  are provided with a predetermined interval with the mesh belt  72  through the pile seals  144 . The pile seals  142  and  144 , and the seal roller  146  can suppress that the defibrated material is leaked from the interval between the housing unit  110  and the mesh belt  72 . 
     Moreover, for example, if the web W deposited in the mesh belt  72  has a distribution of a thickness in the width direction (direction of the rotational axis Q) of the mesh belt  72 , or a size of the web W in the width direction (direction of the rotational axis Q) is smaller than a size of the pile seals  142  or the seal roller  146  in the width direction (direction of the rotational axis Q), an interval through which air passes from the outside to the inside of the housing unit  110  may be generated. 
     For example, the sheet manufacturing apparatus  100  has the following characteristics. 
     The sheet manufacturing apparatus  100  has the material supply port  120  that is provided to supply the defibrated material in the direction of the rotational axis Q to the inside of the drum unit  60  by the airflow A 1  and the air intake port  130  that is provided to supply air that does not contain the material in the direction of the rotational axis Q of the drum unit  60  to the inside of the drum unit  60  by the airflow A 2 . Thus, in the sheet manufacturing apparatus  100 , it is possible to suppress (it is possible to rectify) that airflow is disturbed on the inside of the drum unit  60  and to deposit the defibrated material on the mesh belt  72  with high uniformity. Furthermore, for example, the sheet manufacturing apparatus  100  can suppress that airflow is disturbed on the inside of the housing unit  110 . 
     For example, if the air intake port is not provided, the airflow entering the inside of the drum unit from the material supply port collides with the inner surface of the housing unit and then spiral airflow is generated and the airflow may be disturbed on the inside of the drum unit. On the other hand, in the sheet manufacturing apparatus  100 , it is possible to generate airflow A 3  flowing from the air intake port  130  to the suction unit  76  by providing the air intake port  130 . Thus, it is possible to suppress (it is possible to weaken the airflow colliding with the inside of the housing unit) that the airflow A 1  collides with the inside of the housing unit by allowing the airflow A 1  within the material supply port  120  to enter the inside of the drum unit  60  and to suppress that the airflow on the inside of the drum unit  60  is disturbed. 
     Furthermore, in the sheet manufacturing apparatus  100 , it is possible to reduce the intake air amount of air sucked from the interval (as described above, interval generated by the web W having the distribution of the thickness in the width direction of the mesh belt  72 ) through which air passes from the outside to the inside of the housing unit  110  to the inside of the housing unit by providing the air intake port  130 . Thus, in the sheet manufacturing apparatus  100 , it is possible to suppress that the web W is disturbed (for example, the web W is turned up) and to deposit the defibrated material on the mesh belt  72  with high uniformity by sucking air from the interval. 
     Thus, in the sheet manufacturing apparatus  100 , it is possible to manufacture the sheet S having high uniformity of the grammage. 
     Here,  FIG. 6  is a graph illustrating the grammage with respect to the position of the sheet in the width direction (direction of the rotational axis Q) thereof. It can be seen from  FIG. 6  that if the air intake port is provided, uniformity of the grammage in the width direction is increased compared to a case where the air intake port is not provided. Moreover,  FIG. 6  illustrates results of measurements of the grammages of the sheets in the sheet manufacturing apparatus  100  (sheet manufacturing apparatus having the air intake port) as illustrated in  FIGS. 1 to 5  and a sheet manufacturing apparatus (sheet manufacturing apparatus having no air intake port) having the same configuration as the sheet manufacturing apparatus  100  except that the air intake port  130  is not provided. 
     Furthermore, in the sheet manufacturing apparatus  100 , as described above, it is possible to suppress that the first flow rate is changed depending on the change in the second flow rate by providing the air intake port  130 . For example, in a case where the air intake port  130  is not provided, if the second flow rate is increased, the first flow rate is also increased, a mixing degree of the first screened matter (the defibrated material) passing through the screening unit  40  and the additives containing resin is lowered (the defibrated material and the additives are not easily mixed), and then the uniformity of strength of the sheet may be lowered. In the sheet manufacturing apparatus  100 , it is possible to avoid such a problem and to manufacture the sheet S having high uniformity of the strength. 
     In the sheet manufacturing apparatus  100 , the air intake port  130  is provided on the side opposite to the mesh belt  72  side further than the material supply port  120 . Thus, in the sheet manufacturing apparatus  100 , it is possible to further reliably suppress that the airflow entering the inside of the drum unit  60  from the material supply port  120  collides with the inner surface of the housing unit  110  compared to a case where the air intake port  130  is provided on the mesh belt  72  side further than the material supply port  120 . 
     Moreover, in the sheet manufacturing apparatus according to the invention, similar to the deposition unit  60 , the screening unit  40  is configured of the rotatable drum unit in which the plurality of openings are formed and the housing unit  110  covering the portion, in which at least openings of the screening unit  40  are formed, is provided. The screening unit  40  may have the material supply port  120  that is provided to supply the defibrated material to the inside of the screening unit  40  and the air intake port  130  that is provided to supply air that does not contain the defibrated material to the inside of the screening unit  40 . 
     Furthermore, in the sheet manufacturing apparatus according to the invention, the defibrated material passing through the defibrating unit  20  may be transported to a classifying unit (not illustrated) through the pipe  3 . Then, a classified material that is classified in the classifying unit may be transported to the screening unit  40 . The classifying unit classifies the defibrated material passing through the defibrating unit  20 . Specifically, the classifying unit screens and removes relatively small defibrated material and the defibrated material (resin particles, coloring materials, additives, and the like) having low density in the defibrated materials. Thus, it is possible to increase a ratio of fibers that are relatively large and have high density in the defibrated materials. As the classifying unit, for example, cyclone, elbow jet, eddy classifier, and the like are used. 
     2. Modification Example of Sheet Manufacturing Apparatus 
     2.1. First Modification Example 
     Next, a sheet manufacturing apparatus according to a first modification example of the embodiment will be described with reference to the drawing.  FIG. 7  is a sectional view schematically illustrating a sheet manufacturing apparatus  200  according to the first modification example of the embodiment and illustrates the same cross section as that of  FIG. 4 . 
     Hereinafter, in the sheet manufacturing apparatus  200  according to the first modification example of the embodiment, configurations different from the example of the sheet manufacturing apparatus  100  according to the embodiment will be described and description of the same configurations will be omitted. This is equally applied to sheet manufacturing apparatuses according to second to sixth modification examples illustrated below. 
     In the sheet manufacturing apparatus  100  described above, as illustrated in  FIG. 4 , the air intake port  130  is provided on the side opposite to the mesh belt  72  side further than the material supply port  120 . 
     On the other hand, in the sheet manufacturing apparatus  200 , as illustrated in  FIG. 7 , an air intake port  130  is provided on a mesh belt  72  side (position close to the mesh belt  72 ) further than a material supply port  120 . That is, a distance between the air intake port  130  and the mesh belt  72  is smaller than a distance the material supply port  120  and the mesh belt  72 . As illustrated in  FIG. 7 , the air intake port  130  is positioned between the material supply port  120  and the mesh belt  72  when viewed in a direction of a rotational axis Q. In the illustrated example, a shape of the air intake port  130  is elliptical, but is not specifically limited, and may be, for example, circular. 
     In the sheet manufacturing apparatus  200 , the air intake port  130  is provided on the mesh belt  72  side further than the material supply port  120 . Thus, in the sheet manufacturing apparatus  200 , it is possible to reduce an intake air amount (intake air amount to an inside of a housing unit  110 ) from a portion between a pile seal  144  (for example, see  FIG. 5 ) and the mesh belt  72 , for example, compared to a case where the air intake port  130  is provided on a side opposite to the mesh belt  72  side further than the material supply port  120 . Thus, in the sheet manufacturing apparatus  200 , it is possible to further reliably suppress that a web W is disturbed. Furthermore, in the sheet manufacturing apparatus  200 , it is possible to achieve low density of the pile seal  144  and to reduce a width of the pile seal  144 . In addition, it is possible to achieve sliding load reduction and low torque driving of the mesh belt  72 . 
     2.2. Second Modification Example 
     Next, a sheet manufacturing apparatus according to a second modification example of the embodiment will be described with reference to the drawing.  FIG. 8  is a sectional view schematically illustrating a sheet manufacturing apparatus  300  according to the second modification example of the embodiment and illustrates the same cross section as  FIG. 4 . 
     In the sheet manufacturing apparatus  100  described above, as illustrated in  FIG. 4 , the air intake port  130  is provided on the side opposite to the mesh belt  72  side further than the material supply port  120 . 
     On the other hand, in the sheet manufacturing apparatus  300 , similar to the sheet manufacturing apparatus  200  described above, an air intake port  130  is provided on a mesh belt  72  side further than a material supply port  120 . Furthermore, as illustrated in  FIG. 8 , in the sheet manufacturing apparatus  300 , the air intake port  130  is provided in a position closer to an end portion  113  of a housing unit  110  on a downstream side in a transport direction of a web W further than the material supply port  120 . That is, a distance between the air intake port  130  and the end portion  113  is smaller than a distance between the material supply port  120  and the end portion  113 . As illustrated in  FIG. 8 , the air intake port  130  is, for example, positioned between the material supply port  120  and the end portion  113  when viewed in a direction of a rotational axis Q. 
     The end portion  113  of the housing unit  110  is an end portion on a side in a direction a in which the web W is transported. When the web W is transported from the inside to the outside of the housing unit  110 , the end portion  113  forms an outlet of the web W. The end portion  113  comes into contact with a pile seals  142 . 
     In the sheet manufacturing apparatus  300 , the air intake port  130  is provided on the mesh belt  72  side further than the material supply port  120  and is provided in the position closer to the end portion  113  of the housing unit  110  on the downstream side in the transport direction of the web W further than the material supply port  120 . Thus, in the sheet manufacturing apparatus  300 , for example, it is possible to reduce an intake air amount (the intake air amount to the inside of the housing unit  110 ) from an interval below the end portion  113  compared to a case where the air intake port  130  is provided in a position farther to the end portion  113  than the material supply port  120 , when the web W is transported from the inside to the outside of the housing unit  110 . Thus, in the sheet manufacturing apparatus  300 , it is possible to further reliably suppress that the web W is disturbed. 
     2.3. Third Modification Example 
     Next, a sheet manufacturing apparatus according to a third modification example of the embodiment will be described with reference to the drawing.  FIG. 9  is a sectional view schematically illustrating a sheet manufacturing apparatus  400  according to the third modification example of the embodiment and illustrates the same cross section as  FIG. 4 . 
     In the sheet manufacturing apparatus  100  described above, as illustrated in  FIGS. 3 and 4 , one air intake port  130  is provided in each of the side wall units  112   a  and  112   b  of the housing unit  110 . 
     On the other hand, in the sheet manufacturing apparatus  400 , as illustrated in  FIG. 9 , a plurality of air intake ports  130  are provided in each of side wall units  112   a  and  112   b  of a housing unit  110  and the plurality of air intake ports  130  are provided in a periphery of a material supply port  120  when viewed in the direction of the rotational axis Q. In the illustrated example, the plurality of air intake ports  130  are provided in the periphery of the material supply port  120  at equal intervals and are provided so as to surround the material supply port  120 . Moreover, the number of the air intake ports  130  is not specifically limited. 
     In the sheet manufacturing apparatus  400 , the plurality of air intake ports  130  are provided in the periphery of the material supply port  120 . Thus, in the sheet manufacturing apparatus  400 , for example, it is possible to further reliably suppress that airflow on an inside of a drum unit  60  is disturbed compared to a case where one air intake port  130  is provided in each of the side wall units  112   a  and  112   b.    
     2.4. Fourth Modification Example 
     Next, a sheet manufacturing apparatus according to a fourth modification example of the embodiment will be described with reference to the drawings.  FIGS. 10 and 11  are sectional views schematically illustrating a sheet manufacturing apparatus  500  according to the fourth modification example of the embodiment. Moreover,  FIG. 10  illustrates the same cross section as  FIG. 3  and  FIG. 11  illustrates the same cross section as  FIG. 4 . 
     In the sheet manufacturing apparatus  100  described above, as illustrated in  FIGS. 3 and 4 , the housing unit  110  and the transport pipe  54  are integrally provided. 
     On the other hand, in the sheet manufacturing apparatus  500 , as illustrated in  FIGS. 10 and 11 , a housing unit  110  and a transport pipe  54  are not integrally provided. Through holes  116  greater than a material supply port  120  in size are provided in side wall units  112   a  and  112   b  of the housing unit  110 . Specifically, as illustrated in  FIG. 11 , the through hole  116  is greater than the material supply port  120  in size when viewed in a direction of a rotational axis Q. As illustrated in  FIG. 11 , the material supply port  120  overlaps the through hole  116  and is provided on an inside of an outer edge of the through hole  116  when viewed in the direction of the rotational axis Q. The through hole  116  is a through hole communicating an inside of the housing unit  110  with an outside thereof and extends in the direction of the rotational axis Q. A transport pipe  54  has an inner surface  55   a  forming (defining) the material supply port  120 . 
     An air intake port  130  is an interval that is formed between a surface  118  of side wall units  112   a  and  112   b  of the housing unit  110  forming the through holes  116  and an outer surface  55   b  of a transport pipe  54  on a side opposite to the inner surface  55   a . As illustrated in  FIG. 11 , the air intake port  130  is provided in a periphery of the material supply port  120  when viewed in the direction of the rotational axis Q. As illustrated in  FIG. 11 , the air intake port  130  is provided to surround the material supply port  120  when viewed in the direction of the rotational axis Q. 
     In the sheet manufacturing apparatus  500 , the air intake port  130  is the interval that is formed between the surface  118  of the housing unit  110  forming the through holes  116  and the outer surface  55   b  of a transport pipe  54 . Thus, in the sheet manufacturing apparatus  500 , the air intake port  130  can be provided to surround the material supply port  120 . Therefore, in the sheet manufacturing apparatus  500 , for example, it is possible to further reliably suppress that airflow on an inside of a drum unit  60  is disturbed compared to a case where the air intake port  130  is provided not to surround the material supply port  120 . 
     2.5. Fifth Modification Example 
     Next, a sheet manufacturing apparatus according to a fifth modification example of the embodiment will be described with reference to the drawing.  FIG. 12  is a sectional view schematically illustrating a sheet manufacturing apparatus  600  according to the fifth modification example of the embodiment and illustrates the same cross section as  FIG. 3 . 
     In the sheet manufacturing apparatus  100  described above, as illustrated in  FIG. 3 , the housing unit  110  has the first side wall unit  112   a  and the second side wall unit  112   b  covering the drum unit  60  in the direction of the rotational axis Q. 
     On the other hand, in the sheet manufacturing apparatus  600 , as illustrated in  FIG. 12 , a housing unit  110  does not have side wall units  112   a  and  112   b . The sheet manufacturing apparatus  600  has a first lid unit  150   a  and a second lid unit  150   b  covering a drum unit  60  in a direction of a rotational axis Q. The lid units  150   a  and  150   b  are different members from the housing unit  110 . 
     Material supply ports  120  are provided in the lid units  150   a  and  150   b . The first lid unit  150   a  is connected to a first portion  54   a  of a transport pipe  54 . The second lid unit  150   b  is connected to a second portion  54   b  of the transport pipe  54 . The lid units  150   a  and  150   b  may be integrally provided with the transport pipe  54 . The lid units  150   a  and  150   b  are connected to an outer peripheral surface  60   b  of the drum unit  60  through pile seals  140 . 
     Air intake ports  130  are provided in the lid units  150   a  and  150   b . In the illustrated example, one air intake port  130  is provided both above and below the material supply port  120  in each of the lid units  150   a  and  150   b . Although not illustrated, the air intake port  130  may be provided to surround the material supply port  120  when viewed in the direction of the rotational axis Q. 
     In the sheet manufacturing apparatus  600 , for example, it is possible to manufacture the sheet S having high uniformity of the grammage similar to the sheet manufacturing apparatus  100 . 
     2.6. Sixth Modification Example 
     Next, a sheet manufacturing apparatus according to a sixth modification example of the embodiment will be described with reference to the drawing.  FIG. 13  is a sectional view schematically illustrating a sheet manufacturing apparatus  700  according to the sixth modification example of the embodiment and illustrates the same cross section as  FIG. 3 . 
     In the sheet manufacturing apparatus  100  described above, as illustrated in  FIG. 3 , the housing unit  110  has the first side wall unit  112   a  and the second side wall unit  112   b  covering the drum unit  60  in the direction of the rotational axis Q. 
     On the other hand, in the sheet manufacturing apparatus  700 , as illustrated in  FIG. 13 , similar to the sheet manufacturing apparatus  600  described above, a housing unit  110  does not have side wall units  112   a  and  112   b , and has a first lid unit  150   a  and a second lid unit  150   b.    
     In the sheet manufacturing apparatus  700 , different from the sheet manufacturing apparatus  600  described above, the lid units  150   a  and  150   b  are not connected to an outer peripheral surface  60   b  of a drum unit  60  through pile seals  140 . 
     Air intake ports  130  are intervals that are formed between the lid units  150   a  and  150   b , and an inner peripheral surface  60   c  of the drum unit  60  on a side opposite to an outer peripheral surface  60   b . In the illustrated example, one air intake port  130  is provided both above and below a material supply port  120  in each of the lid units  150   a  and  150   b . Although not illustrated, the air intake ports  130  are provided to surround the material supply port  120  when viewed in a direction of a rotational axis Q. 
     In the sheet manufacturing apparatus  700 , for example, it is possible to manufacture the sheet S having high uniformity of the grammage similar to the sheet manufacturing apparatus  100 . 
     Moreover, the sheet S that is manufactured by the sheet manufacturing apparatus according to the invention mainly refers to those having a sheet shape. However, the sheet S is not limited to the sheet shape and may be a board shape or a web shape. The sheet in the present specification is divided into paper and non-woven fabric. Paper includes aspects formed in a thin sheet shape in which pulp or waste paper is a raw material and includes recording paper for writing or printing, wallpaper, wrapping paper, colored paper, drawing paper, Kent paper, and the like. Non-woven fabric has a thickness thicker than that of paper or has a strength lower than that of paper, and includes a general non-woven fabric, fiber board, tissue paper (cleaning tissue paper), kitchen paper, cleaner, filter, liquid (waste ink or oil) absorption material, sound-absorbing material, thermal insulation material, cushioning material, mat, and the like. Moreover, as the raw material, plant fibers such as cellulose, chemical fibers such as polyethylene terephthalate (PET) and polyester, and animal fibers such as wool and silk may be included. 
     The invention may omit some of a range having characteristics and advantages described in this application or may combine each of the embodiments and the modification examples. Moreover, a part of the configuration of the manufacturing unit  102  may be omitted, other configurations may be added to the manufacturing unit  102 , or the manufacturing unit  102  may be replaced by a known configuration. 
     The invention includes a substantially same configuration (for example, same configuration in a function, a method, and a result or the same configuration in the object and the effect) as the configuration described in the embodiments. Furthermore, the invention includes a configuration that replaces non-essential parts of the configuration described in the embodiments. Furthermore, the invention includes a configuration which can perform the same operational effects or can achieve the same object as the configuration described in the embodiments. Furthermore, the invention includes a configuration obtained by adding a known technique to the configuration described in the embodiments. 
     The entire disclosure of Japanese Patent Application No.: 2014-238484, filed Nov. 26, 2014 and 2015-129594, filed Jun. 29, 2015 are expressly incorporated by reference herein.