Sheet manufacturing apparatus

A sheet manufacturing apparatus includes a defibrating unit configured to defibrate a defibration object containing fibers in the air, a supply unit configured to supply additive agents to defibrated material that has been defibrated in the defibrating unit, a deposition unit configured to deposit the defibrated material and the additive agents, and a heating unit configured to heat a web deposited by the deposition unit. The supply unit has a moisture adding unit configured to add moisture to the additive agents.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2014-038190 filed on Feb. 28, 2014. The entire disclosure of Japanese Patent Application No. 2014-038190 is hereby incorporated herein by reference.

BACKGROUND

1. Technical Field

The present invention relates to a sheet manufacturing apparatus.

2. Related Art

Conventionally, a liquid absorbing body is formed by supplying additive agents, such as thermal fusion-bondable materials, to natural cellulose fibers and synthetic fibers, then mixing and defibrating in the air to form a mat, and heating the mat (e.g, see Japanese Laid-Open Patent Publication No. H9-158024).

However, when additive agents are supplied to natural cellulose fibers in the manufacturing process of the liquid absorbing body, the problem was that the additive agents were charged by static electricity and adhered to the interior of the transfer path, so the additive agents could not be stably transferred.

SUMMARY

The present invention solves at least a portion of the problems described above and can be implemented in the following embodiments or applied examples.

A sheet manufacturing apparatus in this applied example is a sheet manufacturing apparatus provided with a defibrating unit configured to defibrate a defibration object that contains fibers in the air, a supply unit configured to supply additive agents to defibrated material that has been defibrated in the defibrating unit, a deposition unit configured to deposit the defibrated material and the additive agents, and a heating unit configured to heat a web deposited by the deposition unit. The supply unit has a moisture adding unit configured to add moisture to the additive agents.

According to this configuration, moisture is added to the additive agents being supplied. By doing this, static electricity becomes difficult to form because the additive agents carry moisture. Additionally, adherence of the additive agents due to charging can be prevented.

The sheet manufacturing apparatus in the above applied example is provided with a first transfer unit configured to transfer the defibrated material to the deposition unit from the defibrating unit. The supply unit has a storage unit configured to store the additive agents and a second transfer unit configured to transfer the additive agents from the storage unit to the first transfer unit. The moisture adding unit is configured to add moisture to an interior of the second transfer unit.

According to this configuration, electrostatic charging of the additive agents and adherence to the interior of the transfer unit can be suppressed because moisture is added to the interior of the transfer unit for transferring additive agents.

The moisture adding unit of the sheet manufacturing apparatus related to the above applied example has a sprayer port configured to spray moisture. The sprayer port is arranged in the second transfer unit on a side closer to the storage unit than the first transfer unit.

According to this configuration, charging of the additive agents and adhering to the inside of the transfer unit are suppressed by adding moisture from the upstream side in the transfer direction in the second transfer unit.

The supply unit of the sheet manufacturing apparatus related to the above applied examples is configured to select to supply additive agents and not supply additive agents. The moisture adding unit is configured to add moisture when the additive agents are supplied.

According to this configuration, because moisture is added only when additive agents are supplied from the supply unit, it is possible to limit excess moisture that is the result of adding moisture when additive agents are not supplied.

The supply unit of the sheet manufacturing apparatus related to the above applied examples is configured to control a supplied amount of the additive agents. The moisture adding unit is configured to control adding of moisture. The moisture adding unit is configured to control the adding of moisture in response to the supplied amount of the additive agents.

According to this configuration, the appropriate amount of moisture can be added by also controlling the added amount of moisture to correspond to the supplied amount of additive agents.

In the sheet manufacturing apparatus related to the above applied examples, a second moisture adding unit configured to add moisture to the first transfer unit is provided further downstream in a transfer direction of the defibrated material than the flow combining portion of the first transfer unit and the second transfer unit.

According to this configuration, a material that is a mixture of fibers and additive agents becomes more difficult to charge by adding moisture; and charging and adherence to the interior of the first transfer unit can be suppressed.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

First and second embodiments of the present invention are described below with reference to the drawings. In the drawings below, the scale of each part differs from the actual scale in order for each part to be a size that can be discerned.

First Embodiment

First, the configuration of the sheet manufacturing apparatus is explained. For example, the sheet manufacturing apparatus is based on a technology in which the raw material (defibration object) Pu, such as refined pulp sheets or used papers, is formed into a new sheet Pr. The sheet manufacturing apparatus related to this embodiment is provided with a defibrating unit that defibrates the defibration object containing fibers in the air, a supply unit that supplies additive agents to the defibrated material that was defibrated in the defibrating unit, a deposition unit that deposits the defibrated material and the additive agents, and a heating unit that heats the web deposited on the deposition unit, wherein the supply unit has a moisture adding unit for adding moisture to the additive agents. A specific configuration of the sheet manufacturing apparatus is explained below.

FIG. 1is a schematic diagram showing the configuration of a sheet manufacturing apparatus related to this embodiment.FIG. 2is a schematic diagram showing the configuration of the additive agent supply unit. As shown inFIG. 1, the sheet manufacturing apparatus1of this embodiment is provided with a feed-in unit10, a crushing unit20, a defibrating unit30, a classifying unit40, a screening unit50, an additive agent supply unit60as the supply unit, a deposition unit70, and a heating unit150. A control unit is also supplied to control these parts.

The feed-in unit10feeds in used paper Pu into the crushing unit20. For example, the feed-in unit10is provided with a tray11where a plurality of sheets of used paper Pu is stacked and stored, and an automatic transfer mechanism12that can continuously feed in the used paper Pu in the tray11into the crushing unit20. The used paper Pu fed into the sheet manufacturing apparatus1is, for example, A4-size paper that is currently in common use in offices.

The crushing unit20cuts up the supplied used paper Pu into pieces of paper of several centimeters square. The crushing unit20is an apparatus with a configuration that is provided with a crushing blade21to widen the cutting width of the blade of an ordinary shredder. Thus, the supplied used paper Pu can be easily cut into pieces of paper. Then, the cut-up crushed paper is supplied through a transfer path201to the defibrating unit30.

The defibrating unit30is provided with a rotating blade (not shown) that rotates to defibrate by untangling the crushed paper (defibration object including fibers) supplied from the crushing unit20into a fibrous form. In this application, the material that is defibrated by the defibrating unit30is referred to as the defibration object, and the material passed by the defibrating unit30is referred to as the defibrated material. The defibrating unit30in this embodiment defibrates in a dry system in the air. The defibrating process of the defibrating unit30defibrates and separates the coating materials on the paper, such as printed inks or toners, and blur-preventing materials, into particles no larger than several tens of micrometers (μm) (hereinafter, referred to as “ink particles”). Consequently, the defibrated material output from the defibrating unit30is fibers and ink particles obtained by defibrating the pieces of paper. Then the unit becomes a mechanism that generates airflow by rotating the rotating blade and transfers in the air the defibrated fibers that passed through the transfer path202to the classifying unit40by carrying the fibers on the airflow. As needed, an airflow generating apparatus may be separately provided to generate airflow to transfer defibrated fibers that were defibrated in the defibrating unit30through the transfer path202to the classifying unit40.

The classifying unit40uses the airflow to classify the introduced material that was input. In this embodiment, the defibrated material, which is the introduced material, is classified into ink particles and fibers. For example, the classifying unit40can use a cyclone to classify by airflow the transferred fibers into ink particles and deinked fibers (deinked defibrated material). Another type of airflow classifier may be used instead of the cyclone. In this case, an airflow classifier other than a cyclone is used, for example, an elbow jet or an eddy classifier. The airflow classifier generates a rotating airflow to separate and classify based on the differences in the centrifugal force received according to the size and density of the defibrated material. Thus, the material is classified into ink particles that are relatively small and have low density and fibers that are larger than ink particles and have high density. The removal of ink particles from the fibers is referred to as deinking.

The classifying unit40in this embodiment is a tangential inlet cyclone and comprises an inlet40athat inputs from the defibrating unit30, a cylindrical part41that attaches the inlet40ain the tangential direction, a conical part42that is connected to the lower part of the cylindrical part41, a lower outlet40bthat is installed in the lower part of the conical part42, and an upper discharge port40cfor discharging fine particles that is installed in the center of the upper part of the cylindrical part41. The diameter of the conical part42becomes smaller in the downward direction of the perpendicular.

In the classifying process, the airflow carrying the defibrated material that was introduced from the inlet40aof the classifying unit40is changed into circular motion by the cylindrical part41and the conical part42and classifies by applying centrifugal force. Then fibers that are larger and have higher density than the ink particles move to the lower outlet40b, and ink particles that are relatively small and have low density are introduced as fine particles with air to the upper discharge port40c, and deinking proceeds. Then, a short fiber mixture that contains a large quantity of ink particles is discharged from the upper discharge port40cof the classifying unit40. The short fiber mixture that contains a large quantity of the discharged ink particles is then passed through a transfer path206connected to the upper discharge port40cof the classifying unit40to be recovered in a receiving unit80. In addition, the classified material that contains the classified fibers that passed through a transfer path203from the lower outlet40bof the classifying unit40is transferred in the air to the screening unit50. The transfer from the classifying unit40to the screening unit50may be by airflow when classifying, or may be by gravity from the classifying unit40, which is on top, to the screening unit50, which is on the bottom. A suction unit for efficiently suctioning the short fiber mixture from the upper discharge port40cmay be positioned in the upper discharge port40cof the classifying unit40or the transfer path206, and the like.

The screening unit50screens the classified material that contains fibers classified by the classifying unit40that was passed from a drum unit51that has a plurality of openings. More specifically, the classified material that contains fibers classified by the classifying unit40is screened into passed material that passed through the openings and residue that did not pass through the openings. The screening unit50of this embodiment is provided with a mechanism to disperse the classified material in the air by circular motion.

Then, the passed material (defibrated material) that passed through the openings by the screening of the screening unit50is transferred to the deposition unit70. More specifically, the screening unit50and the deposition unit70are connected by transfer path204, which is the first transfer unit. Then, the passed material (defibrated material) that passed through the openings by the screening of the screening unit50is received by a hopper56, and then transferred in the air via transfer path204to the deposition unit70. The transfer from the screening unit50to the deposition unit70may be transfer by a blower, which is not shown, that generates airflow, or transfer by gravity from the screening unit50on the top to the deposition unit70on the bottom. In addition, the residue that did not pass through the openings by the screening of the screening unit50is returned again as defibration object via transfer path205, which is the transfer path, to the defibrating unit30. Thus, the residue is not discarded and is reused (recycled).

In addition, the additive agent supply unit60for supplying additive agents to the passed material (defibrated material) being transferred is provided between the screening unit50and the deposition unit70in the transfer path204. In addition to resin (e.g., fusion-bondable resin or thermoplastic resin), the additive agents are, for example, flame retardants, whitening agents, sheet strengthening agents, and sizing agents. The forms of the additive agents may be powders or fibers. The additive agents are stored in an additive agent storage unit61, which is the storage unit provided in the additive agent supply unit60.

The additive agent supply unit60is provided with transfer path208as the second transfer unit that is connected to transfer path204. Additive agent F stored in the additive agent storage unit61is supplied from a supply port62to transfer path208by a discharge mechanism, such as a screw feeder, and is transferred from transfer path208to transfer path204.

In addition, a moisture adding unit300is arranged in the additive agent supply unit60. The moisture adding unit300adds moisture to the interior of the transfer path208. As shown inFIG. 2, the moisture adding unit300is provided with a liquid storage unit302that stores water for adding moisture and a sprayer port301that sprays water moisture. The sprayer port301is arranged in transfer path208on the side closer to the additive agent storage unit61than transfer path204. In this embodiment, the sprayer port301is arranged to face the supply port62that supplies additive agent T from the additive agent storage unit61. Thus, moisture is added to additive agent T in the transfer direction of additive agent F, and the additive agent T can be prevented from being charged and adhering to transfer path208. In addition, moisture is added to the interior of transfer path208.

Additionally, the additive agent supply unit60can select to supply or not supply additive agent T. The moisture adding unit300is configured so that moisture is added when additive agent T is supplied. Consequently, the process for adding moisture is not conducted when additive agent T is not supplied. Thus, it is possible to limit excess moisture that is the result of adding moisture when additive agent T is not supplied. Furthermore, the additive agent supply unit60can control the supplied amount of additive agent T. The moisture adding unit300is configured so that the addition of moisture is controlled in response to the supplied amount of additive agent T. For example, when additive agent T that is supplied is a fusible resin, 1 to 8% by weight of water is given with respect to the supplied weight of the fusible resin. Thus, moisture can be appropriately added for the added fusible resin, and excess moisture can be limited. When excess moisture results, additive agent T sometimes has difficulty moving in transfer path208and transfer path204. As shown inFIG. 2, transfer path208has a part with a pipeline form and a part that expands at the end of the pipeline form. The moisture is sprayed in a mist from the sprayer port301toward the expanded part. From this expanded part, additive agent T supplied from the supply port62is easily received, and moisture is easily added to additive agent T.

Returning toFIG. 1, the deposition unit70deposits passed material containing fibers (defibrated material) that was fed in from the transfer path204and additive agents (material containing resin) to form a web W. The deposition unit70has a mechanism that uniformly disperses fibers in the air and a mechanism that deposits the dispersed fibers on a mesh belt73. The web W related to this embodiment refers to the form of the material including fibers and resin. Consequently, even if there are changes in the state of the web, such as the dimensions when the web is heated, or subjected to pressure, or cut, or transferred, this is still indicated as the web.

First, a forming drum71that feeds in fibers and resin to the interior is arranged in the deposition unit70as the mechanism that uniformly disperses fibers in the air. By driving the forming drum71to rotate, the resin (additive agent) can be uniformly mixed into the passed material (fibers). A screen having a plurality of small holes is provided in the forming drum71. The forming drum71is driven to rotate, and the resin (additive agents) is uniformly mixed in the passed material (fibers), and the fibers that passed through the small holes and the mixture of fibers and resin can be uniformly dispersed in the air.

An endless mesh belt73that is formed by using the stretching rollers72to stretch the mesh is arranged below the forming drum71. At least one of the stretching rollers72is rotated, and the mesh belt73moves in one direction.

In addition, a suction apparatus75is provided perpendicularly below the forming drum71as the suction unit that generates airflow downward in the perpendicular direction through the mesh belt73. The suction apparatus75can suction the fibers dispersed in the air on the mesh belt73.

The fibers that passed through the screen with small holes of the forming drum71are deposited on the mesh belt73by the suction force due to the suction apparatus75. By moving the mesh belt73in one direction, the web W that includes fibers and resin and is deposited in a continuous shape can be formed. Due to the continuous dispersion from the forming drum71and moving the mesh belt73, the web W is formed in a continuous band. The mesh belt73may be made of either metal, resin, or nonwoven cloth, if fibers can be deposited, and airflow can be passed. If the hole diameter of the mesh of the mesh belt73is too large, fibers enter into the mesh and the web W (sheet) becomes uneven when formed. On the other hand, if the hole diameter of the mesh is too small, the suction apparatus75has difficulty forming a stable airflow. Therefore, preferably, the hole diameter of the mesh is appropriately adjusted. The suction apparatus75can be configured to form an airtight box with an opening for a window having the desired size below the mesh belt73, and suctions air through the window to produce negative pressure inside the box with respect to the atmosphere.

The web W formed on the mesh belt73is transferred by a transfer unit100. The transfer unit100of this embodiment indicates the transfer process of the web W from the mesh belt73until finally feeding into a stacker160as sheets Pr (web W). Consequently, in addition to the mesh belt73, various rollers function as a part of the transfer unit100. The transfer unit may be the transfer belt and at least one of the transfer rollers. Specifically, the web W formed on the mesh belt73, which is a part of the transfer unit100, is transferred along the transfer direction (arrow in the drawing) by the rotational motion of the mesh belt73. Next, the web W transfers along the transfer direction (arrow in the drawing) from the mesh belt73. In this embodiment, the deposition unit70and the transfer unit100are a part of a forming unit200that uses the web W to form the sheet Pr.

A pressure unit is arranged on the downstream side of the deposition unit70in the transfer direction of the web W. The pressure unit in this embodiment is pressure unit140that has roller141for applying pressure to the web W. By passing the web W between the roller141and a stretching roller72, pressure can be applied to the web W. By doing this, the strength of the web W can be improved.

Rollers120before the cutting unit are arranged on the downstream side of the pressure unit140in the transfer direction of the web W. The rollers120before the cutting unit are composed of a pair of rollers121. One of the pair of rollers121is a drive control roller, and the other is a following roller.

In addition, a one-way clutch is used in the drive transmission unit to rotate the rollers120before the cutting unit. The one-way clutch is configured to have a clutch mechanism that transmits rotational force in only one direction and idles for the opposite direction. Thus, when there is a velocity difference between the rollers125after the cutting unit and the rollers120before the cutting unit, and excessive tension is applied to the web W, limiting of the tension on the web W and tearing of the web W can be prevented because of idling on the side of the rollers120before the cutting unit.

A cutting unit110for cutting the web W in a direction that intersects the transfer direction of the web W being transferred is arranged on the downstream side of the rollers120before the cutting unit in the transfer direction of the web W. The cutting unit110is provided with a cutter and cuts the continuous web W into sheet shapes at the cutting positions set at specified lengths. For example, the cutting unit110can use a rotary cutter. By doing this, cutting is possible while the web W is transferred. Consequently, the transfer of the web W is not stopped during cutting, and the manufacturing efficiency can be improved. The cutting unit110may use various cutters other than a rotary cutter.

The rollers125after the cutting unit are arranged further on the downstream side in the transfer direction of the web W than cutting unit110. The rollers125after the cutting unit are composed of a pair of rollers126. One of the pair of rollers126is a drive control roller, and the other is a following roller.

In this embodiment, tension can be applied to the web W depending on the velocity difference between the rollers120before the cutting unit and the rollers125after the cutting unit. The configuration is such that when tension is applied to the web W, the cutting unit110is driven to cut the web W.

The heating unit150for heating the web W is arranged further on the downstream side in the transfer direction of the web W than the rollers125after the cutting unit. The heating unit150in this embodiment is arranged with a pair of heat and pressure application rollers151for heating and applying pressure to the web W. The heating unit150bonds (fixes) together fibers contained in the web W with resin. By providing a heating component, such as a heater, in the center part of the rotation shaft of the heat and pressure application rollers151, and passing the web W between the pair of heat and pressure application rollers151, heat and pressure can be applied to the web W being transferred. By applying heat and pressure to the web W by the pair of heat and pressure application rollers151, the resin melts and the fibers easily become tangled; and the interval between fibers shortens, and contact points between the fibers increase. Thus, the density increases, and the strength as a web W is improved.

A post-cutting unit130for cutting the web W along the transfer direction of the web W is arranged further on downstream side in the transfer direction of the web W than the heating unit150. The post-cutting unit130is provided with a cutter and cuts at specified cutting positions in the transfer direction of the web W. Thus, sheets Pr (web W) having the desired size are formed. The cut sheets Pr (web W) are stacked on the stacker160.

The sheet related to this embodiment has raw materials that include fibers such as used paper or pulp, and primarily refers to a sheet form. However, the shape is not limited to a sheet, a board form or a web form (shape having indentations and bumps) is acceptable. The raw materials may be plant fibers such as cellulose, and the like; synthetic fibers such as polyethylene terephthalate (PET), polyester, and the like; and animal fibers such as wool, silk, and the like. In this application, a sheet is divided into paper and nonwoven cloth. Paper includes embodiments in a thin sheet, and includes recording paper, wallpaper, wrapping paper, colored paper, and Kent paper that have the objecting of writing or printing. Nonwoven cloth is thicker and has less strength than paper, and includes nonwoven cloth, fiberboard, tissue paper, paper towels, cleaning cloths, filters, liquid absorbing materials, sound absorbing materials, cushioning materials, and mats.

In addition, the used paper in the above embodiments mainly indicates paper for printing and is regarded as used paper unrelated to whether or not it has been used, if a material that was formed into paper is used as the raw material.

According to the above embodiments, the following effects can be obtained.

By spraying water from the moisture adding unit300provided in the additive agent supply unit60toward transfer path208, moisture is added to the additive agents supplied to transfer path208. Thus, the additive agents become difficult to charge because of the moisture that is held and are prevented from adhering to transfer path208of the additive agents.

Second Embodiment

Next, the configuration of the sheet manufacturing apparatus related to the second embodiment is explained. A sheet manufacturing apparatus1arelated to this embodiment adds a second moisture adding unit310to the configuration of the sheet manufacturing apparatus1related to the first embodiment. Consequently, structures other than the second moisture adding unit310are omitted from the description because the structures are similar to the structures of the sheet manufacturing apparatus1related to the first embodiment. The details are described below.

FIG. 3is a partial schematic drawing that shows the configuration of the sheet manufacturing apparatus related to this embodiment. As shown inFIG. 3, the sheet manufacturing apparatus1aof this embodiment is provided with a second moisture adding unit310that adds moisture to transfer path204further downstream in the transfer direction of the defibrated material than the flow combining portion of transfer path204, which is the first transfer unit, and transfer path208, which is the second transfer unit.

The second moisture adding unit310is provided with a liquid storage unit312for storing liquid (e.g., water) for adding moisture and a sprayer port311for spraying liquid. The sprayer port311is arranged toward transfer path204from the opening part69. By doing this, moisture can be easily added to the transfer material that is transferred in transfer path204. In addition, moisture can be easily added to the interior of transfer path204.

In addition, the second moisture adding unit310may be configured to conduct a moisture adding process in response to the presence or absence of passed material that is the defibrated material and that additive agents that were mixed together and passed through transfer path204. In this case, the moisture adding process is conducted when the passed material is passed through transfer path204. The moisture adding process is not conducted when passed material is not passed to transfer path204. Furthermore, the addition of moisture may be controlled in response to the transferred amount of passed material that passed through transfer path204. Thus, the addition of moisture can be controlled to an appropriate amount, and excess moisture can be limited.

According to the above embodiment, in addition to the effects of the first embodiment, the following effects can be obtained.

A material of a mixture of fibers and additive agents becomes more difficult to charge by the addition of moisture further on the downstream side in the transfer direction of the defibrated material than the flow combining portion of transfer path204and transfer path208, and charging and adherence to the interior of transfer path204can be suppressed.

GENERAL INTERPRETATION OF TERMS