Patent Publication Number: US-11384482-B2

Title: Web manufacturing apparatus and sheet manufacturing apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2018-209382, filed Nov. 7, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a web manufacturing apparatus and a sheet manufacturing apparatus. 
     2. Related Art 
     JP-T-8-503255 discloses a method for manufacturing a shaped article from a mixture of fibrous material and binder powder. In this method, first, fibers are spread out in a sheet shape and mechanically and preliminarily consolidated to obtain a sheet-shaped fibrous structure. Next, the binder powder is distributed in the obtained sheet-shaped fibrous structure. Water is distributed to moisten the sheet-shaped fibrous structure in which the binder powder is distributed, at 5% by weight to 60% by weight of water as a percentage of the overall dry weight of the fiber and binder mixture. The moistened sheet-shaped fibrous structure is then subjected to pressing and heat treatment to obtain the shaped article. 
     In the method disclosed in JP-T-8-503255, it is conceivable that a series of processes are consecutively performed by transporting the sheet-shaped fibrous structure in sequence to areas where these respective processes are performed. 
     However, the processes may be intentionally or unintentionally stopped at a stage when the moistened sheet-shaped fibrous structure has not yet been transported to an area where pressing and heat treatment are performed. In such cases, the moistened sheet-shaped fibrous structure is left waiting as it is, and drying may proceed over time depending on environmental conditions. If this occurs, there is a concern of deterioration of the mechanical properties of the sheet-shaped fibrous structure. 
     When the processes then recommence in a state in which drying is proceeding, the sheet-shaped fibrous structure may be transported in a state in which its mechanical properties have deteriorated. There is accordingly a concern of creases occurring in the sheet-shaped fibrous structure, or the thickness of the sheet-shaped fibrous structure becoming inconsistent during transportation. 
     SUMMARY 
     The present disclosure addresses the above issues, and may be realized in the following manner. 
     According to an aspect of the present disclosure, a web manufacturing apparatus includes a transport section configured to transport a web containing fiber, a web humidifier configured to humidify the web, and a control section configured to control operation of the transport section and the web humidifier. When transportation of the web by the transport section is stopped, the control section causes the transport section to recommence transportation of the web after the web is humidified by the web humidifier. 
     According to another aspect of the present disclosure, a sheet manufacturing apparatus configured to manufacture a sheet from a web which is pressed includes the web manufacturing apparatus of the present disclosure, and a press section configured to press the web manufactured by the web manufacturing apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view illustrating a sheet manufacturing apparatus according to a first embodiment. 
         FIG. 2  is an enlarged view corresponding to part of  FIG. 1 . 
         FIG. 3  is a block diagram of a web manufacturing apparatus illustrated in  FIG. 1 . 
         FIG. 4  is a flowchart illustrating operation of the web manufacturing apparatus illustrated in  FIG. 1 . 
         FIG. 5  is an enlarged view corresponding to part of a sheet manufacturing apparatus according to a second embodiment. 
         FIG. 6  is a block diagram of a web manufacturing apparatus according to the second embodiment. 
         FIG. 7  is a flowchart illustrating operation of the web manufacturing apparatus illustrated in  FIG. 6 . 
         FIG. 8  is an enlarged view corresponding to part of a sheet manufacturing apparatus according to a third embodiment. 
         FIG. 9  is a block diagram of a web manufacturing apparatus according to the third embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     A detailed explanation of a web manufacturing apparatus and a sheet manufacturing apparatus of the present disclosure is given below based on preferable embodiments as illustrated in the accompanying drawings. 
     First Embodiment 
     First, explanation follows regarding a web manufacturing apparatus and a sheet manufacturing apparatus according to a first embodiment. 
       FIG. 1  is a schematic side view illustrating the sheet manufacturing apparatus according to the first embodiment.  FIG. 2  is an enlarged view corresponding to part of  FIG. 1 .  FIG. 3  is a block diagram of a web manufacturing apparatus illustrated in  FIG. 1 . 
     For ease of explanation, three mutually orthogonal axes illustrated in  FIG. 1  will be referred to as an x-axis, a y-axis, and a z-axis. The xy-plane including the x-axis and the y-axis is horizontal, and the z-axis is vertical. The direction indicated by the arrow on each of the axes is referred to as “+”, and the opposite direction thereto is referred to as “−”. The top side of  FIG. 1  is sometimes referred to as upper or upward, and the bottom side thereof is sometimes referred to as lower or downward. The left side of  FIG. 2  is sometimes referred to as being “upstream” and the right side thereof is sometimes referred to as being “downstream”. 
     As illustrated in  FIG. 1 , a sheet manufacturing apparatus  100  includes a web manufacturing apparatus  1 , a sheet forming section  20 , a cutting section  21 , a stacking section  22 , and a collection section  27 . 
     The web manufacturing apparatus  1  includes a feedstock supply section  11 , a crushing section  12 , a defibration section  13 , a sorting section  14 , a first web forming section  15 , a shredding section  16 , a mixer  17 , a disentangling section  18 , a second web forming section  19 , a control section  28 , a back face transport section  29 , and a web humidifier  237 . Each of the sections configuring the web manufacturing apparatus  1  is electrically coupled to the control section  28 , and the respective operations thereof are controlled by the control section  28 . 
     The sheet manufacturing apparatus  100  also includes a humidifier  231 , a humidifier  232 , a humidifier  233 , a humidifier  234 , a humidifier  235 , and a humidifier  236 . The sheet manufacturing apparatus  100  also includes a blower  261 , a blower  262 , and a blower  263 . 
     The sheet manufacturing apparatus  100  executes the following processes in sequence: a feedstock supply process, a crushing process, a defibration process, a sorting process, a first web forming process, a dividing process, a mixing process, a disentangling process, a second web forming process, a sheet forming process, and a cutting process. 
     Explanation follows regarding the configuration of each of these sections. 
     The feedstock supply section  11  is the section where the feedstock supply process is performed, in which a feedstock M 1  is supplied into the crushing section  12 . Examples of the feedstock M 1  include sheet-form materials made from fiber-containing materials that include cellulose fibers. Cellulose fibers are any material formed into a fibrous shape that has cellulose, namely cellulose in the narrow sense, as the main component compound thereof. The cellulose fibers may include hemicellulose, lignin, or the like in addition to cellulose in the narrow sense. There is no particular limitation to the form of the feedstock M 1 , which may be woven, non-woven, or the like. The feedstock M 1  may, for example, be recycled-paper manufactured by defibrating and reusing old paper, or synthetic paper such as YUPO paper (registered trademark). The feedstock M 1  is not necessarily recycled paper. The feedstock M 1  in the present embodiment is old paper that may be either previously used or scrap. 
     The crushing section  12  is the section where the crushing process is performed, in which the feedstock M 1  supplied from the feedstock supply section  11  is crushed in air, such as in atmospheric air. The crushing section  12  includes a pair of crushing blades  121 , and a chute  122 . 
     The pair of crushing blades  121  rotate in opposite directions to each other so as to crush the feedstock M 1  between the blades, i.e. so as to be able to cut the feedstock M 1  into coarse fragments M 2 . The shape and size of the coarse fragments M 2  are preferably tailored to the defibration process in the defibration section  13  and are, for example, preferably small fragments with a side length of not more than 100 mm, and more preferably small fragments with a side length from 10 mm to 70 mm. 
     The chute  122  is disposed below the pair of crushing blades  121  and is, for example, configured with a funnel shape. The chute  122  is thereby able to receive falling coarse fragments M 2  that have been crushed by the crushing blades  121 . 
     The humidifier  231  is disposed above the chute  122  and alongside the pair of crushing blades  121 . The humidifier  231  humidifies the coarse fragments M 2  inside the chute  122 . The humidifier  231  is configured by a vaporizing humidifier device, or by a warm air vaporizing humidifier device, that includes a moist non-illustrated filter and that feeds humidified air of raised humidity into the coarse fragments M 2  by passing air through the filter. Feeding the humidified air into the coarse fragments M 2  enables the coarse fragments M 2  to be suppressed from adhering with static electricity to the chute  122  or the like. 
     The chute  122  is coupled to the defibration section  13  by a pipe  241 . The coarse fragments M 2  collected in the chute  122  are fed out through the pipe  241  to the defibration section  13 . 
     The defibration section  13  is the section that performs the defibration process on the coarse fragments M 2  in air, namely performs dry defibration. A defibrated material M 3  can be generated from the coarse fragments M 2  by performing the defibration process in the defibration section  13 . “Defibration” as referred to here means taking the coarse fragments M 2  configured from plural fibers bound together, and disentangling the fibers into individual fibers. The disentangled product is what is referred to as the defibrated material M 3 . The defibrated material M 3  may be in the form of lines or strips. There may still be defibrated material M 3  present that is somewhat intertwined in agglomerations, formed into what is referred to as “clumps”. 
     The defibration section  13  of the present embodiment is, for example, configured by an impeller mill including a high speed rotor and a liner positioned around the outer periphery of the rotor. The coarse fragments M 2  flowing into the defibration section  13  are squeezed between the rotor and the liner and defibrated thereby. 
     The defibration section  13  is able to generate a flow of air, i.e. an airflow, from the crushing section  12  toward the sorting section  14  by rotation of the rotor. This enables the coarse fragments M 2  to be sucked into the defibration section  13  through the pipe  241 . After the defibration process, the defibrated material M 3  can then be sent on toward the sorting section  14  through a pipe  242 . 
     The blower  261  is installed partway along the pipe  242 . The blower  261  is an airflow generating device for generating an airflow toward the sorting section  14 . This promotes transportation of the defibrated material M 3  toward the sorting section  14 . 
     The sorting section  14  is the section where the sorting process is performed, in which the defibrated material M 3  is sorted into long and short fibers. The defibrated material M 3  is sorted in the sorting section  14  into a first sorting M 4 - 1 , and a second sorting M 4 - 2  larger than the first sorting M 4 - 1 . The first sorting M 4 - 1  is for fibers of a length suitable for manufacturing a sheet S at a later stage. The average length in the first sorting M 4 - 1  is preferably from 1 μm to 30 μm. The second sorting M 4 - 2  includes, for example, insufficiently defibrated fibers, defibrated fibers that have aggregated together excessively, etc. 
     The sorting section  14  includes a drum  141 , and a housing  142  housing the drum  141 . 
     The drum  141  is configured by a cylindrical mesh, and is a sieve that rotates about its own central axis. The defibrated material M 3  flows into the drum  141 . Rotation of the drum  141  sorts defibrated material M 3  smaller than the size of the mesh into the first sorting M 4 - 1 , and sorts defibrated material M 3  equal to or larger than the mesh size into the second sorting M 4 - 2 . 
     The first sorting M 4 - 1  falls through the drum  141 . 
     The second sorting M 4 - 2  is fed out into a pipe  243  coupled to the drum  141 . The opposite end of the pipe  243  to the drum  141 , namely an downstream end thereof, is coupled to the pipe  241 . The second sorting M 4 - 2  that has passed through the pipe  243  merges with the coarse fragments M 2  inside the pipe  241 , and flows back into the defibration section  13  together with the coarse fragments M 2 . The second sorting M 4 - 2  is thereby returned to the defibration section  13 , and is again subjected to the defibration process together with the coarse fragments M 2 . 
     The first sorting M 4 - 1  from the drum  141  falls while being dispersed in the air, and falls toward the first web forming section  15  positioned below the drum  141 . The first web forming section  15  is the section where the first web forming process is performed, in which a first web M 5  is formed from the first sorting M 4 - 1 . The first web forming section  15  includes a mesh belt  151 , three tension rollers  152 , and a suction section  153 . 
     The mesh belt  151  is an endless belt for the first sorting M 4 - 1  to accumulate on. The mesh belt  151  is entrained around the three tension rollers  152 . The first sorting M 4 - 1  lying on the mesh belt  151  is transported downstream by rotational driving of the tension rollers  152 . 
     The first sorting M 4 - 1  is configured by fibers equal to or larger than the mesh size of the mesh belt  151 . The first sorting M 4 - 1  is thereby restricted from passing through the mesh belt  151 , and can accordingly be accumulated on the mesh belt  151 . The first sorting M 4 - 1  is formed into a layer as the first web M 5  by accumulating on the mesh belt  151  while being transported downstream along with the mesh belt  151 . 
     There is a concern that there might, for example, be dirt and dust etc. mixed in with the first sorting M 4 - 1 . The dirt and dust is, for example, generated by the crushing and defibration. Such dirt and dust is collected in the collection section  27 , described later. 
     The suction section  153  is a suction mechanism that suctions air downwards from the mesh belt  151 . The dirt and dust that has passed through the mesh belt  151  can thereby be suctioned along with the air. 
     The suction section  153  is coupled through a pipe  244  to the collection section  27 . The dirt and dust suctioned by the suction section  153  are collected in the collection section  27 . 
     A pipe  245  is also coupled to the collection section  27 . A blower  262  is installed partway along the pipe  245 . This enables a suction force to be generated at the suction section  153  by operation of the blower  262 . The formation of the first web M 5  on the mesh belt  151  is promoted thereby. The first web M 5  has had the dirt and dust etc. removed therefrom. 
     The housing  142  is coupled to the humidifier  232 . The humidifier  232  is configured by a vaporizing humidifier device similar to the humidifier  231 . Humidified air is thereby fed into the housing  142 . The first sorting M 4 - 1  can be humidified by the humidified air, enabling the first sorting M 4 - 1  to be suppressed from adhering with static electricity to the inside walls of the housing  142 . 
     The humidifier  235  is disposed downstream of the sorting section  14 . The humidifier  235  is configured by an ultrasonic humidifier device that creates a mist of water. This enables moisture to be supplied to the first web M 5 , thereby adjusting the moisture content of the first web M 5 . Such adjustment enables the first web M 5  to be suppressed from adhering with static electricity to the mesh belt  151 . The first web M 5  is thereby readily separated from the mesh belt  151  at the position where the mesh belt  151  returns on itself around one of the tension rollers  152 . 
     The shredding section  16  is disposed downstream of the humidifier  235 . The shredding section  16  is the section where the dividing process is performed, in which the first web M 5  that has separated from the mesh belt  151  is divided. The shredding section  16  includes a rotatably supported propeller  161  and a housing  162  housing the propeller  161 . The first web M 5  can be divided by the rotating propeller  161 . The first web M 5  when divided becomes shreddings M 6 . The shreddings M 6  fall inside the housing  162 . 
     The housing  162  is coupled to the humidifier  233 . The humidifier  233  is configured by a vaporizing humidifier device similar to the humidifier  231 . Humidified air is thereby fed into the housing  162 . The humidified air enables the shreddings M 6  to be suppressed from adhering with static electricity to the propeller  161  and the inside walls of the housing  162 . 
     The mixer  17  is disposed downstream of the shredding section  16 . The mixer  17  is the section where the mixing process is performed, in which the shreddings M 6  and a resin P 1  are mixed together. The mixer  17  includes a resin feeder  171 , a pipe  172 , and a blower  173 . 
     The pipe  172  couples the housing  162  of the shredding section  16  and a housing  182  of the disentangling section  18  together, and is a flow path for a mixed material M 7 , a mixture of the shreddings M 6  and the resin P 1 , to pass through. 
     The resin feeder  171  is coupled partway along the pipe  172 . The resin feeder  171  includes a screw feeder  174 . The resin P 1  can be fed into the pipe  172  as a powder or as granules by rotational driving of the screw feeder  174 . The resin P 1  fed into the pipe  172  is mixed with the shreddings M 6  to form the mixed material M 7 . 
     Note that the resin P 1  is employed to bind fibers together in a later process and although it may, for example, be a thermoplastic resin or curable resin, a thermoplastic resin is preferably employed therefor. Examples of such thermoplastic resins include: AS resins; ABS resins; polyolefins and modified polyolefins such as such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA) and the like; acrylic resins such as poly (methyl methacrylate); polyesters such as poly vinyl chloride, polystyrene, polyethylene terephthalate, polybutylene terephthalate and the like; polyamides such as NYLON 6, NYLON 46, NYLON 66, NYLON 610, NYLON 612, NYLON 11, NYLON 12, NYLON 6-12, NYLON 6-66 and the like; polyphenylene ethers; polyacetals; polyethers; polyphenylene oxides; polyether ether ketones; polycarbonates; polyphenylene sulfides; thermoplastic polyimides; polyether imides; liquid crystal polymers such as aromatic polyesters; and various types of thermoplastic elastomer such as styrene-based, polyolefin-based, polyvinyl chloride-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, transpolyisoprene-based, fluorine rubber-based, or chlorinated polyethylene-based thermoplastic elastomers. One resin selected from the above resins may be employed as the thermoplastic resin alone, or two or more resins selected therefrom may be employed in combination. A polyester resin or a resin including polyester is preferably employed as the thermoplastic resin. 
     In addition to the resin P 1 , other substances may also be fed out from the resin feeder  171 . These include a colorant to color the fibers, an anti-caking agent to suppress aggregation of the fibers and aggregation of the resin P 1 , a fire retardant to render the fibers etc. less liable to combust, and a paper strengthening agent to increase the paper strength of the sheet S. Alternatively these other substances may be compounded with the resin P 1  in advance before then being fed out from the resin feeder  171 . 
     The blower  173  is installed partway along the pipe  172  at a position downstream of the resin feeder  171 . The shreddings M 6  and the resin P 1  are mixed together by the action of a rotating section such as fan blades of the blower  173 . The blower  173  is capable of generating an airflow toward the disentangling section  18 . The shreddings M 6  and the resin P 1  can be stirred inside the pipe  172  by this airflow. The mixed material M 7  can accordingly be introduced into the disentangling section  18  in a state in which the shreddings M 6  and the resin P 1  have been uniformly dispersed. The shreddings M 6  in the mixed material M 7  are disentangled by the process of passing through the inside of the pipe  172  so as to result in a finer fibrous form. 
     The disentangling section  18  is the section where the disentangling process is performed to disentangle the intertwined fibers in the mixed material M 7  from each other. The disentangling section  18  includes a drum  181  and the housing  182  housing the drum  181 . 
     The drum  181  is configured by a cylindrical mesh, and is a sieve that rotates about its own central axis. The mixed material M 7  flows into the drum  181 . Rotation of the drum  181  enables the fibers and the like in mixed material M 7  smaller than the size of the mesh to pass through the drum  181 . The mixed material M 7  is disentangled by this action. 
     The housing  182  is coupled to the humidifier  234 . The humidifier  234  is configured by a vaporizing humidifier device similar to the humidifier  231 . Humidified air is thereby fed into the housing  182 . The inside of the housing  182  can be humidified by the humidified air, enabling the mixed material M 7  to be suppressed from adhering with static electricity to the inside walls of the housing  182 . 
     The mixed material M 7  disentangled by the drum  181  is dispersed in the air while falling toward the second web forming section  19  positioned below the drum  181 . The second web forming section  19  is the section where the second web forming process is performed to form a second web M 8  from the mixed material M 7 . The second web forming section  19  includes a mesh belt  191 , tension rollers  192 , and a suction section  193 . 
     The mesh belt  191  is an endless belt for the mixed material M 7  to accumulate on. The mesh belt  191  is entrained around the four tension rollers  192 . The mixed material M 7  on the mesh belt  191  is transported downstream by rotational driving of the tension rollers  192 . 
     Almost all of the mixed material M 7  on the mesh belt  191  is the size of the mesh of the mesh belt  191  or larger. This enables the mixed material M 7  to be restricted from passing through the mesh belt  191 , and thereby enables the mixed material M 7  to be accumulated on the mesh belt  191 . The mixed material M 7  is formed into a layer as the second web M 8  by accumulating on the mesh belt  191  while being transported downstream along with the mesh belt  191 . 
     The suction section  193  is a suction mechanism that suctions air downwards from the mesh belt  191 . This enables the mixed material M 7  on the mesh belt  191  to be suctioned, thereby promoting accumulation of the mixed material M 7  on the mesh belt  191 . 
     A pipe  246  is coupled to the suction section  193 . The blower  263  is installed partway along the pipe  246 . A suction force can be generated at the suction section  193  by operation of the blower  263 . 
     The humidifier  236  is disposed downstream of the disentangling section  18 . The humidifier  236  is configured by an ultrasonic humidifier device similar to the humidifier  235 . This enables moisture to be supplied to the second web M 8 , thereby adjusting the moisture content of the second web M 8 . Such adjustment enables the second web M 8  to be suppressed from adhering with static electricity to the mesh belt  191 . The second web M 8  is thereby readily separated from the mesh belt  191  at the position where the mesh belt  191  returns on itself around one of the tension rollers  192 . Note that humidifier  236  is not limited to being an ultrasonic humidifier device, and may be a vaporizing humidifier device. 
     The total moisture content added by the humidifier  231  to the humidifier  236  is, for example, preferably from 0.5 parts by mass to 20 parts by mass with respect to 100 parts by mass of material prior to humidification. 
     The back face transport section  29 , described later, is disposed downstream of the second web forming section  19 , and the sheet forming section  20  is further disposed downstream of the back face transport section  29 . The sheet forming section  20  is the section where the sheet forming process is performed to form the sheet S from the second web M 8 . The sheet forming section  20  includes the press section  201  and a heating section  202 . 
     The press section  201  includes a pair of calender rollers  203 . The second web M 8  can be pressed between the calender rollers  203  without being heated. The density of the second web M 8  is raised thereby. The level of heating at this point is, for example, preferably a level of heating that will not melt the resin P 1 . The second web M 8  is then transported toward the heating section  202 . One of the pair of calender rollers  203  is a lead roller driven by operation of a non-illustrated motor, and the other is a following roller. 
     The heating section  202  includes a pair of heating rollers  204 . The second web M 8  can be pressed between the heating rollers  204  while being heated. The resin P 1  is melted by the heating and pressing, and the fibers in the second web M 8  are bonded together by the molten resin P 1 . The sheet S is formed thereby. The sheet S is then transported toward the cutting section  21 . Note that one of the pair of heating rollers  204  is a lead roller driven by operation of a non-illustrated motor, and the other is a following roller. 
     The cutting section  21  is disposed downstream of the sheet forming section  20 . The cutting section  21  is the section where the cutting process is performed to cut the sheet S. The cutting section  21  includes first cutters  211  and second cutters  212 . 
     The first cutters  211  cut the sheet S along a direction intersecting with the transport direction of the sheet S, and in particular a direction orthogonal thereto. 
     The second cutters  212  cut the sheet S in a direction parallel to the transport direction of the sheet S downstream of the first cutters  211 . This cutting removes unwanted portions at the two end portions of the sheet S (end portions in the y axis direction), so as to fix the width of the sheet S. The portions removed by this cutting are called “offcuts”. 
     A sheet S of the desired shape and size is obtained by this cutting by the first cutters  211  and the second cutters  212 . Each sheet S is then transported further downstream and stacked in the stacking section  22 . 
     The back face transport section  29  is a transport section that transports the second web M 8  in the downstream direction. The back face transport section  29  includes a mesh belt  291  and plural tension rollers  292 . The mesh belt  291  is an endless belt that is entrained around the three tension rollers  292 . The second web M 8  lying under the mesh belt  291  is transported downstream by rotational driving of the tension rollers  292 . The back face transport section  29  is disposed above the mesh belt  191  described previously. Part of an extension range of the mesh belt  291  overlaps an extension range of the mesh belt  191  described previously. The second web M 8  is inserted through this overlapping part. Thus, an upper face of the second web M 8  abuts the mesh belt  291 , and a lower face of the second web M 8  abuts the mesh belt  191 . The second web M 8  is thereby held between the mesh belt  291  and the mesh belt  191  from above and below so as to be more stably transported. 
     If required, the back face transport section  29  may include a sensor or the like to detect whether or not the second web M 8  is present below the mesh belt  291 . A detection signal from the sensor is output to the control section  28 . 
     Note that since the second web M 8  is humidified by the humidifier  236 , the second web M 8  has a sufficient moisture content while the sheet manufacturing apparatus  100  is running. Thus, the second web M 8  also has good mechanical properties, and there is no impediment to transportation by the back face transport section  29 . 
     However, the sheet manufacturing apparatus  100  sometimes stops running, either intentionally or unintentionally. When this occurs, depending on the operational status of the sheet manufacturing apparatus  100  the second web M 8  may remain directly under the back face transport section  29 . When the sheet manufacturing apparatus  100  stops running, both transportation of the second web M 8  and humidification of the second web M 8  by the humidifier  236  also stop, such that there is a possibility of the moisture contained in the second web M 8  gradually evaporating, causing the moisture content of the second web M 8  to drop over time. This tendency is particularly marked when the environment around the sheet manufacturing apparatus  100  is dry. 
     When the sheet manufacturing apparatus  100  starts running again after having stopped, the back face transport section  29  also starts running again, and downstream transportation of the second web M 8  remaining under the back face transport section  29  recommences. However, when the moisture content of the second web M 8  that has remained under the back face transport section  29  drops while the sheet manufacturing apparatus  100  is stopped, there is a possibility of deterioration to the mechanical properties of the second web M 8  as a result. In such cases, there is a concern that creases might occur in the second web M 8  or the thickness of the second web M 8  might become inconsistent as a result of transportation by the back face transport section  29 . 
     To address this, the web manufacturing apparatus  1  according to the present embodiment includes a web humidifier  237  capable of humidifying the second web M 8 . The web humidifier  237  humidifies the second web M 8  prior to transportation recommencing after transportation of the second web M 8  has stopped. As illustrated in  FIG. 1 , the web humidifier  237  is provided above the drum  181 , and humidifies the back face transport section  29  and its surroundings, i.e. a space HS in which the second web M 8  is being transported. By humidifying the space HS, the second web M 8  is also humidified and its moisture content is raised. Note that when the mesh belt  291  allows air to pass through, the second web M 8  can also be humidified through the mesh belt  291 . 
     Transportation by the back face transport section  29  recommences after the second web M 8  has been humidified by the web humidifier  237 . In this manner, the second web M 8  is transported in a state in which sufficient mechanical properties are ensured, thereby suppressing a reduction in quality such as that described above. 
     Note that the space HS refers to a range that the web humidifier  237  is capable of humidifying, and may be an enclosed space surrounded by external panels, equipment, or the like, or may be an open space open to the exterior. 
     As illustrated in  FIG. 3 , the control section  28  includes a central processing unit (CPU)  281 , and a storage section  282 . The above-described operation of the web manufacturing apparatus  1  is controlled by the control section  28 . Namely, operation of the back face transport section  29  and the web humidifier  237  is controlled based on control signals from the control section  28 . 
     Note that the position of the web humidifier  237  is not limited to the above-described position, and may be any position as long as it is capable of humidifying the space HS. 
       FIG. 4  is a flowchart illustrating operation of the web manufacturing apparatus illustrated in  FIG. 1 . 
     As previously described, sometimes manufacture of the second web M 8  by the web manufacturing apparatus  1  stops, either intentionally or unintentionally. For example, transportation of the second web M 8  may stop unintentionally due to a power cut or the like, or transportation may be stopped intentionally. When transportation of the second web M 8  is stopped in such a manner, the control section  28  stores information, for example the time of stopping and the presence or absence of the second web M 8 , in the storage section  282  as required. Prior to transportation of the second web M 8  recommencing, the control section  28  determines whether or not the second web M 8  is present under the back face transport section  29  based on the information stored in the storage section  282 , or based on a signal from the back face transport section  29 . Note that the information on which this determination is based is not limited to the above-described information. 
     When the second web M 8  is not present under the back face transport section  29 , the control section  28  recommences transportation of the second web M 8 . When the second web M 8  is present under the back face transport section  29 , the control section  28  starts humidification of the second web M 8  by the web humidifier  237 . 
     The humidification amount by the web humidifier  237  when this is performed should raise the moisture content of the second web M 8  sufficiently to ensure that the required mechanical properties are satisfied. For example, the control section  28  according to the present embodiment performs control so as to start humidification of the second web M 8  by the web humidifier  237 , and then stop humidification of the second web M 8  after a predetermined duration has elapsed. Using a preset duration to control the humidification amount in this manner allows operation of the web humidifier  237  to be controlled based on a predetermined duration stored in the storage section  282  without needing to make any complex calculations or the like, thereby enabling configuration of the control section  28  to be simplified. 
     This predetermined duration is one parameter affecting the humidification amount, and may be a preset duration, or may be a duration that changes dynamically based on various conditions and the like. Note that in consideration of securing the humidification amount while reducing downtime, the predetermined duration from the start to end of humidification by the web humidifier  237  is preferably from 5 minutes to 60 minutes, and is more preferably from 10 minutes to 40 minutes. When the duration of humidification by the web humidifier  237  is below the above lower limit, the humidification amount may be too low depending on the configuration of the second web M 8 , and so the moisture content of the second web M 8  might not be sufficiently raised. When the humidification duration exceeds the above upper limit, the humidification amount may be too high depending on the configuration of the second web M 8 , and so issues such as the second web M 8  sticking to the back face transport section  29  might arise. 
     After humidification of the second web M 8  has stopped, the control section  28  recommences transportation of the second web M 8  by the back face transport section  29 . This also recommences manufacture of the second web M 8 . 
     As described above, the web manufacturing apparatus  1  according to the present embodiment includes the back face transport section  29 , this being a transport section configured to transport the fiber-containing second web M 8 , the web humidifier  237  configured to humidify the second web M 8 , and the control section  28  configured to control operation of the back face transport section  29  and the web humidifier  237 . When transportation of the second web M 8  has stopped, the control section  28  recommences transportation of the second web M 8  by the back face transport section  29  after the second web M 8  has been humidified by the web humidifier  237 . 
     In the web manufacturing apparatus  1 , the second web M 8  is transported in a state having sufficient mechanical properties, thereby suppressing a deterioration in the quality of the second web M 8 . This enables a high quality second web M 8  to be manufactured, even after the web manufacturing apparatus  1  has been stopped and then started running again. Employing such a second web M 8  ultimately enables a high quality sheet S to be manufactured. 
     Note that despite differing slightly according to the thickness and so on of the second web M 8 , the ratio by mass of the moisture content of the second web M 8  after humidification is preferably no less than 3.5%, and is more preferably from 4.0% to 10.0%. When the moisture content is within this range, the second web M 8  will have sufficient mechanical properties, while the generation of surplus moisture due to excessive moisture content is suppressed. This enables a second web M 8  to be manufactured that in turn enables manufacture of a higher quality sheet S. 
     Note that the moisture content of the second web M 8  may for example be measured using a paper moisture meter HK-300 manufactured by Kett Electric Laboratory. 
     Although transportation of the second web M 8  recommences after humidification by the web humidifier  237  has stopped in the present embodiment, transportation may recommence prior to humidification by the web humidifier  237  stopping. Moreover, instead of the humidification duration, the control section  28  may control a humidification amount per unit of time, i.e. a humidification rate, or may control both the humidification duration and the humidification rate. 
     Although there is no particular limitation to the method of humidification by the web humidifier  237 , a vaporizing humidifier device is preferably employed. A vaporizing humidifier device is less likely to generate large droplets, thereby enabling issues associated with droplets, such as only the surface of the second web M 8  being humidified and the internal humidity level thereof not rising, to be suppressed. Furthermore, applying an airflow enables humidification to be performed over a comparatively wide range, enabling the second web M 8  to be evenly humidified even when the second web M 8  to be humidified has a large surface area. This enables the occurrence of creases or the like accompanying uneven humidification to be suppressed. 
     When the second web M 8  is at a position where the second web M 8  is more liable to dry out in the process, the web humidifier  237  is preferably provided close to this position. Specifically, in  FIG. 2 , as the second web M 8  is transferred from the back face transport section  29  to the press section  201  of the sheet forming section  20 , the second web M 8  is in an unsupported state. The second web M 8  is exposed to the air while in this unsupported state, which promotes drying of the second web M 8 . Thus, the space HS is preferably set so as to include an area between the back face transport section  29  and the press section  201 , and placement of the web humidifier  237  is appropriately set such that the entire space HS is humidified, i.e. such that at least the second web M 8  positioned between the back face transport section  29  and the press section  201  is humidified. This enables the moisture content of the second web M 8  to be more reliably raised by humidification, and enables any deterioration in mechanical properties to be more reliably suppressed. This ultimately facilitates manufacture of a high quality sheet S using the sheet manufacturing apparatus  100 . 
     Note that the area of the space HS between the back face transport section  29  and the press section  201  refers to the area between an upstream end of the back face transport section  29  and the press section  201 . The space HS may be set so as to include an area between the disentangling section  18  and the back face transport section  29 . 
     As described above, the sheet manufacturing apparatus  100  according to the present embodiment includes the web manufacturing apparatus  1  and the press section  201  that presses the second web M 8  manufactured by the web manufacturing apparatus  1 , and the sheet manufacturing apparatus  100  manufactures sheets S from the pressed second web M 8 . 
     This sheet manufacturing apparatus  100  enables a high quality second web M 8  to be manufactured by the web manufacturing apparatus  1  even after the sheet manufacturing apparatus  100  has stopped and then started running again, thereby ultimately enabling a high quality sheet S to be manufactured. 
     Second Embodiment 
       FIG. 5  is an enlarged view corresponding to part of a sheet manufacturing apparatus according to a second embodiment.  FIG. 6  is a block diagram of a web manufacturing apparatus according to the second embodiment.  FIG. 7  is a flowchart illustrating operation of the web manufacturing apparatus illustrated in  FIG. 6 . 
     Explanation follows regarding the second embodiment with reference to the drawings. The following explanation is focused on the differences to the embodiment described above, and explanation of similar matter thereto will be omitted. Note that configurations in the drawings that are similar to those in the embodiment described above are appended with the same reference numerals. 
     The present embodiment is similar to the first embodiment, except in that a control section controls operation of each section based on a detection result of a space temperature/humidity detection section. 
     In the first embodiment described above, control is performed such that after humidification of the second web M 8  by the web humidifier  237  has started, humidification by the web humidifier  237  is stopped after a predetermined duration has elapsed. However, in the present embodiment, control is performed such that the humidification amount by the web humidifier  237  is adjusted based on the humidity in the space HS as detected by a space temperature/humidity detection section  31 , this being a first humidity detection section. This enables the moisture content of the second web M 8  to be optimized. 
     As illustrated in  FIG. 5 , a web manufacturing apparatus  1  according to the present embodiment includes the space temperature/humidity detection section  31  provided within the space HS in which the previously-described second web M 8  is positioned. The space temperature/humidity detection section  31  detects the temperature and humidity within the space HS and outputs a detection result to the control section  28  as illustrated in  FIG. 6 . 
     Explanation follows regarding operation of the web manufacturing apparatus  1  according to the present embodiment based on the flowchart illustrated in  FIG. 7 . 
     When transportation of the second web M 8  stops, the control section  28  stores information such as the humidity in the space HS as detected by the space temperature/humidity detection section  31 , in addition to information such as the time of stopping and the presence or absence of the second web M 8 , in the storage section  282 . Prior to transportation of the second web M 8  recommencing, the control section  28  determines whether or not the second web M 8  is present under the back face transport section  29 . 
     When the second web M 8  is not present under the back face transport section  29 , preparation to recommence is complete, and so the control section  28  recommences transportation of the second web M 8 . 
     When the second web M 8  is present under the back face transport section  29 , the control section  28  performs determination based on the humidity in the space HS. Specifically, when the humidity in the space HS is higher than a predetermined value, determination is made that humidification is not required. The control section  28  recommences transportation of the second web M 8  in such cases. Although the predetermined value for the humidity in the space HS on which this determination is based will differ according to the composition and so on of the second web M 8 , a relative humidity of 30% may be given as an example. Determination is made that humidification is not required when the relative humidity in the space HS is higher than 30%. Note that the predetermined value for the humidity in the space HS is not limited to a relative humidity of 30%, and may for example be any relative humidity from 20% to 50%. 
     When the humidity in the space HS is the predetermined value or below, determination is made that humidification is required. Namely, when the humidity detected by the space temperature/humidity detection section  31 , this being a first humidity detection section, is the predetermined value or below, the control section  28  starts humidification of the second web M 8  by the web humidifier  237 . Determination as to whether or not humidification is required can be made based on a detected humidity value, without needing to make any calculation or the like, thereby enabling configuration of the control section  28  to be simplified. 
     The duration of humidification by the web humidifier  237  may be adjusted based on the humidity in the space HS as detected by the space temperature/humidity detection section  31 . Namely, a relationship between the detected humidity, the humidification duration, and the moisture content may be acquired in advance, and the humidification duration computed based on this relationship so as to optimize the moisture content of the second web M 8 . This enables an increase in downtime due to excessive humidification to be suppressed, while optimizing the moisture content of the second web M 8  and improving the mechanical properties of the second web M 8 . Note that when controlling the humidification amount, humidification may be performed for a computed humidification duration based on a detected humidity, or the humidity may be detected in real time and humidification performed while adjusting the humidification duration based on each detection result. As an example of control by the latter method, humidification is stopped at the point where the relative humidity in the space HS has reached from 40% to 60%. This enables insufficient humidification to be suppressed, and also enables time spent on unnecessary humidification to be shortened. 
     As described above, the web manufacturing apparatus  1  according to the present embodiment includes the space temperature/humidity detection section  31 , this being a first humidity detection section that detects the humidity in the space HS in which the second web M 8  is being transported, and the control section  28  controls operation of the web humidifier  237  based on the detection result of the space temperature/humidity detection section  31 . This enables an increase in downtime due to excessive humidification to be suppressed, while optimizing the moisture content of the second web M 8  and improving the mechanical properties of the second web M 8 . 
     Note that the storage section  282  may store information regarding the temperature of the space HS as detected by the space temperature/humidity detection section  31  if required. The control section  28  may also adjust the humidification duration while taking the temperature into account. When there is no need for temperature information, a space humidity detection section may be employed instead of a space temperature/humidity detection section. 
     A history of the humidity and temperature of the space HS after transportation of the second web M 8  has stopped may also be stored in the storage section  282 . Namely, the extent of the drop in the moisture content of the second web M 8  after transportation has stopped may be estimated based on the history of the environment in which the second web M 8  was present during the period between stopping and recommencing transportation of the second web M 8 . The control section  28  may therefore adjust the humidification amount accordingly based on the estimated extent of the drop in the moisture content so as to compensate for this drop. This enables the moisture content of the second web M 8  to be particularly well-optimized during humidification, thereby enabling a particular contribution to be made to the manufacture of a high quality sheet S. 
     The timing at which humidification of the space HS is started may be the same as the timing at which the sheet manufacturing apparatus  100  starts running again, or may be earlier than this timing. For example, the timing of a task performed prior to the sheet manufacturing apparatus  100  starting to run again is an example of the latter method. Such a task may for example be a task of adding water for humidification, or adding feedstock M 1 . 
     Note that there is no particular limitation to the humidity detection method employed by the space temperature/humidity detection section  31 , and for example a polymer resistance method or a polymer electrostatic capacitance method may be employed. Of these, a polymer resistance method is particularly preferable. A polymer resistance method enables accurate measurements even under high humidity and is structurally simple, and is therefore an effective method of humidity detection by the space temperature/humidity detection section  31 . 
     Moreover, there is no particular limitation to the temperature detection method employed by the space temperature/humidity detection section  31 , and for example a method employing a thermocouple, a resistance thermometer, a thermistor, or an infrared thermometer may be employed. 
     The second embodiment obtains similar advantageous effects to those in the first embodiment. 
     Third Embodiment 
       FIG. 8  is an enlarged view corresponding to part of a sheet manufacturing apparatus according to a third embodiment.  FIG. 9  is a block diagram of a web manufacturing apparatus according to the third embodiment. 
     Explanation follows regarding the third embodiment with reference to the drawings. The following explanation is focused on the differences to the embodiments described above, and explanation of similar matter thereto will be omitted. Note that configurations in the drawings that are similar to those in the embodiments described above are appended with the same reference numerals. 
     The present embodiment is similar to the second embodiment, except in that a control section controls operation of each section based on a detection result of an atmospheric temperature/humidity detection section. 
     In the second embodiment described above, control is performed so as to adjust the humidification amount based on the humidity in the space HS where the second web M 8  is positioned. In the present embodiment, control is performed so as to adjust the humidification amount based on the atmospheric humidity around the sheet manufacturing apparatus  100 . 
     As illustrated in  FIG. 8 , a web manufacturing apparatus  1  according to the present embodiment includes an atmospheric temperature/humidity detection section  32 , serving as a second humidity detection section provided at a position enabling detection of the atmospheric humidity around the sheet manufacturing apparatus  100 . The atmospheric temperature/humidity detection section  32  detects the atmospheric temperature and humidity and outputs a detection result to the control section  28  as illustrated in  FIG. 9 . The control section  28  then controls operation of the web humidifier  237  based on the detection result of the atmospheric temperature/humidity detection section  32 . This enables an increase in downtime due to excessive humidification to be suppressed, while optimizing the moisture content of the second web M 8  and improving the mechanical properties of the second web M 8 . 
     Note that it is sufficient for the atmospheric temperature/humidity detection section  32  to be installed at a position enabling detection of the atmospheric temperature and humidity. The atmospheric temperature/humidity detection section  32  may be provided at the outside of exterior panels of the sheet manufacturing apparatus  100 , or may be provided at the inside of the exterior panels. 
     Explanation follows regarding operation of the web manufacturing apparatus  1  according to the present embodiment based on a flowchart. The flowchart is similar to the chart in  FIG. 7  which refers to the second embodiment. 
     The control section  28  according to the present embodiment makes a determination based on the atmospheric humidity. Specifically, when the atmospheric humidity is higher than a predetermined value, the humidity inside the sheet manufacturing apparatus  100  is also deemed to be high, and determination is made that humidification by the web humidifier  237  is not required. The control section  28  recommences transportation of the second web M 8  in such cases. Although the predetermined value for the atmospheric humidity on which this determination is based will differ according to the composition and so on of the second web M 8 , a relative humidity of 30% may be given as an example. Determination is made that humidification by the web humidifier  237  is not required when the relative atmospheric humidity is higher than 30%. Note that the predetermined value for atmospheric humidity is not limited to a relative humidity of 30%, and may for example be any relative humidity from 20% to 50%. 
     When the atmospheric humidity is the predetermined value or below, determination is made that humidification by the web humidifier  237  is required. The control section  28  starts humidification of the space HS by the web humidifier  237  in such cases. 
     The duration of humidification by the web humidifier  237  may be adjusted based on the atmospheric humidity as detected by the atmospheric temperature/humidity detection section  32 . Namely, a relationship between the detected humidity, the humidification duration, and the moisture content may be acquired in advance, and the humidification duration calculated based on this relationship so as to optimize the moisture content of the second web M 8 . This enables an increase in downtime due to excessive humidification to be suppressed, while optimizing the moisture content of the second web M 8  and improving the mechanical properties of the second web M 8 . 
     Note that the storage section  282  may store information regarding the atmospheric temperature as detected by the atmospheric temperature/humidity detection section  32  if required. The control section  28  may also adjust the humidification duration while taking the temperature into account. When there is no need for temperature information, an atmospheric humidity detection section may be employed instead of an atmospheric temperature/humidity detection section. 
     A history of the atmospheric humidity and temperature after transportation of the second web M 8  has stopped may also be stored in the storage section  282 . The extent of the drop in the moisture content of the second web M 8  after transportation has stopped may be estimated based on this history. The control section  28  may adjust the humidification amount accordingly based on the estimated extent of the drop in the moisture content so as to compensate for this drop. This enables the moisture content of the second web M 8  to be particularly well-optimized during humidification, thereby enabling a particular contribution to be made to the manufacture of a high quality sheet S. 
     The third embodiment obtains similar advantageous effects to those in the first and second embodiments. 
     Note that there is no particular limitation to the humidity detection method employed by the atmospheric temperature/humidity detection section  32 , and for example a polymer resistance method or a polymer electrostatic capacitance method may be employed. Of these, the polymer resistance method is particularly preferable. The polymer resistance method enables accurate measurements even under high humidity and is structurally simple, and is therefore an effective method of humidity detection by the atmospheric temperature/humidity detection section  32 . 
     Moreover, there is no particular limitation to the temperature detection method employed by the atmospheric temperature/humidity detection section  32 , and for example a method employing a thermocouple, a resistance thermometer, a thermistor, or an infrared thermometer may be employed. 
     The third embodiment obtains similar advantageous effects to those in the second embodiment. 
     Note that the second embodiment and the third embodiment may be combined to configure a modified example. In such a case, the web manufacturing apparatus  1  includes both the space temperature/humidity detection section  31  and the atmospheric temperature/humidity detection section  32 . The control section  28  is capable of adjusting the humidification amount based on information regarding the temperature and humidity in the space HS as detected by the space temperature/humidity detection section  31 , and on information regarding the atmospheric temperature and humidity as detected by the atmospheric temperature/humidity detection section  32 . 
     As an example, the web humidifier  237  according to the present modified example operates so as to humidify the second web M 8  at a temperature at which the dew point of the space HS in which the second web M 8  is being transported does not exceed the atmospheric temperature. Specifically, a humidifier device that vaporizes using air at room temperature rather than a warm airflow of heated air should be employed. By controlling the temperature during humidification in this manner, the difference between the temperature of the air discharged from the web humidifier  237  and the atmospheric temperature is reduced, enabling the formation of condensation accompanying humidification to be suppressed. Namely, this enables the formation of condensation due to the humidified air being cooled by the surrounding air and falling below the dew point, and any issues arising as a result thereof, to be suppressed. This enables the second web M 8  to be manufactured in a more consistent manner. 
     Embodiments of a web manufacturing apparatus and a sheet manufacturing apparatus of the present disclosure have been explained above with reference to the drawings. However, the present disclosure is not limited to the above explanation, and each section configuring the web manufacturing apparatus and the sheet manufacturing apparatus may be replaced by a desired configuration capable of exhibiting similar functionality. Moreover, other configurations may be added as desired. 
     The web manufacturing apparatus and the sheet manufacturing apparatus of the present disclosure may also combine the configurations and characteristics of any two or more of the above embodiments. 
     Although the web humidifier  237  for humidifying the space HS is provided in each of the above embodiments, the functionality of the web humidifier  237  may be implemented by the humidifier  234  or the humidifier  236 . Namely, the web humidifier  237  may be omitted, with the space HS being humidified by the humidifier  234  or the humidifier  236  instead. 
     EXAMPLES 
     Explanation follows regarding specific examples of the present disclosure. 
     1. Web Manufacture 
     Example 1 
     A second web M 8  was manufactured directly before reaching a press section using the web manufacturing apparatus illustrated in  FIG. 1  and  FIG. 2 . 
     The second web M 8  was then left under a back face transport section for a full day at an atmospheric temperature of 10° C. and a relative atmospheric humidity of 15%. 
     The following day, the second web M 8  was humidified for 25 minutes by a web humidifier prior to restarting the web manufacturing apparatus. The second web M 8  was extracted in this state as a humidified web. 
     Note that the space in which the second web M 8  was disposed had a relative humidity of 60% following humidification. 
     Examples 2, 3 
     Humidified webs similar to that of Example 1 except for having differing thicknesses and the like were obtained. 
     Comparative Examples 1 to 3 
     With the exception that humidification was not performed, non-humidified webs otherwise similar to those in Examples 1 to 3 were obtained. 
     2. Web Evaluation 
     2.1. Moisture Content Measurement 
     The moisture content of each of the obtained webs was measured using a paper moisture meter (HK-300 manufactured by Kett Electric Laboratory). The measurement results are given in Table 1. 
     2.2. Tensile Load Measurement 
     First, each of the obtained webs was pressed and stretched into sheet form, then cut into a predetermined shape and a test piece obtained. 
     The obtained test piece was then set in a tensile load tester, and the tensile load at break was measured. 
     The obtained measurement values were then evaluated using the below evaluation criteria. 
     Tensile Load Evaluation Criteria 
     A: Tensile load of 2N or greater 
     B: Tensile load of less than 2N 
     The evaluation results are given in Table 1. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                   
                 Example 
                 Example 
                 Example 
                 Comparative 
                 Comparative 
                 Comparative 
               
               
                   
                 Property 
                 Unit 
                 1 
                 2 
                 3 
                 example 1 
                 example 2 
                 example 3 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Manufacturing 
                 Paper 
                 μm 
                 100 
                 97 
                 97 
                 112 
                 121 
                 132 
               
               
                 conditions 
                 thickness 
               
               
                   
                 Basis 
                 g/m 2   
                 88.4 
                 87.2 
                 87.2 
                 93.0 
                 94.6 
                 94.6 
               
               
                   
                 weight 
               
               
                   
                 Density 
                 g/cm 3   
                 0.89 
                 0.90 
                 0.90 
                 0.83 
                 0.78 
                 0.71 
               
               
                 Evaluation 
                 Moisture 
                 % 
                 4.50 
                 5.00 
                 5.50 
                 2.90 
                 2.80 
                 2.90 
               
               
                 result 
                 content 
               
               
                   
                 Load 
                 — 
                 A 
                 A 
                 A 
                 B 
                 B 
                 B 
               
               
                   
               
            
           
         
       
     
     As is clear from Table 1, the webs obtained in each of the Examples had high moisture content and withstood sufficiently high tensile load. In contrast thereto, the webs obtained in each of the Comparative Examples had low moisture content and withstood insufficient tensile load. 
     The above examples confirm that humidification raises the moisture content of the web and is thus capable of enhancing the mechanical properties.