Sheet Manufacturing Apparatus

The present application is based on, and claims priority from JP Application Serial Number 2024-069548, filed Apr. 23, 2024, the disclosure of which is hereby incorporated by reference herein in its entirety.

The present disclosure relates to a sheet manufacturing apparatus.

There has been known an apparatus including a mechanism for supplying a material that is powdered and granular material, an additive, and the like. For example, JP-A-2008-224877 discloses an image forming apparatus provided with a toner bottle for supplying toner which is powdered and granular material.

However, the toner bottle described in JP-A-2008-224877 has a problem that the structure is complicated because the toner bottle has various functions.

A sheet manufacturing apparatus includes: a supply unit that supplies powdered and granular material; and a forming unit that forms a sheet from fibers and the supplied powdered and granular material, the supply unit includes a holding unit that detachably holds a container configured to store the powdered and granular material, and a motor, and the motor rotates the container attached to the holding unit to discharge the powdered and granular material from the container.

A method of producing a sheet includes: rotating a container configured to store powdered and granular material to discharge the powdered and granular material from the container; mixing the discharged powdered and granular material and fibers to form a mixture; depositing the mixture to form a web; and compressing the web to produce a sheet.

In the following embodiment, a sheet manufacturing apparatusthat manufactures sheets from scrap paper will be shown as an example and described with reference to the drawings. The sheet manufacturing apparatusincludes a supply unit configured to supply a binder which is powdered and granular material.

In each of the following drawings, an F-axis and XYZ-axes orthogonal to each other are shown as necessary. The direction indicated by each arrow is defined as the +direction, and the direction opposite to the +direction is defined as the-direction. The Z-axis is parallel to the vertical direction, and the −Z direction corresponds to the vertical direction. The +Z direction is sometimes referred to as the upward direction, and the −Z direction is sometimes referred to as the downward direction. The F-axis intersects the Z-axis, which is the vertical direction, and the Y-axis and is orthogonal to the X-axis. For convenience of illustration, the size of each member is different from the actual size.

The sheet manufacturing apparatusmanufactures sheets Pfrom scrap paper such as used paper by a dry process. The sheet manufacturing apparatusis not limited to dry processes and may be one used in a wet process. The sheet manufacturing apparatusmay manufacture sheets from materials other than used paper, such as virgin paper and paper offcuts. In the present specification, the dry process refers to a process performed in air, such as the atmosphere, rather than a process performed in a liquid.

As illustrated in, the sheet manufacturing apparatusaccording to the present embodiment has a first set of units, a second set of units, and a third set of units. The first set of units, the second set of units, and the third set of unitsare supported by a frame (not illustrated).

In, the directions in which scrap paper C, sheets P, slit pieces S, unnecessary scraps, and the like move are indicated by white arrows. In the sheet manufacturing apparatus, the side in the transportation direction of scrap paper C, a web W, sheets P, and the like is sometimes referred to as “downstream”, and the side in the direction opposite to the transportation direction is sometimes referred to as “upstream”.

The sheet manufacturing apparatusmanufactures sheets Pfrom scrap paper C. In the sheet manufacturing apparatus, the first set of units, the third set of units, and the second set of unitsare disposed from the −Y direction side toward the +Y direction side in side view from the −X direction.

Scrap paper C is transported from the first set of unitsto the second set of unitsthrough a pipepassing across the inside of the third set of units. Then, the scrap paper C is subjected to defibration or the like in the second set of unitsand processed into fibers, to which a binder and the like is added to form a mixture. The mixture is transported to the third set of unitsthrough a pipe. The mixture is processed into a web W in the third set of units, and the web W is formed into a belt-like sheet P. The belt-like sheet Pis cut into sheets Pin the first set of units. In the following description, aggregates of a plurality of fibers are also simply referred to as fibers.

The first set of unitsincludes a raw-material supply device, a measurement unit, a merging portion, and the pipe. In the first set of units, these components are arranged in this order from upstream to downstream. In addition, the first set of unitsalso includes a first cutting unit, a second cutting unit, a tray, and a shredding unit. The first cutting unitand the second cutting unitcut the belt-like sheet Pinto sheets Phaving a predetermined shape. Furthermore, the first set of unitsincludes a water supply unit. The water supply unitis a water storage tank. The water supply unitsupplies water for humidification to each of a first humidification unitand a second humidification unit, which will be described later, through water supply pipes (not illustrated).

The raw-material supply devicestores scrap paper C, which is raw material for sheets P, and supplies it downstream. The raw-material supply deviceincludes a raw-material supply port, a storage portion, and a discharge portion.

Scrap paper C is supplied into the storage portionthrough the raw-material supply port. The scrap paper C contains fibers composed of cellulose and the like and is, for example, shredded used paper. Humidified air is supplied to the inside of the storage portionfrom the second humidification unitincluded in the third set of units.

Scrap paper C is temporarily stored in the storage portionand then transported to the measurement unitthrough the discharge portion. The sheet manufacturing apparatusmay include a shredder located upstream of the storage portionand configured to shred scrap paper C and the like.

The measurement unitincludes a sensorand a supply mechanism (not illustrated). The sensormeasures the mass of scrap paper C. The supply mechanism supplies the scrap paper C weighed by the sensorto the downstream merging portion. Specifically, every time the measurement unitweighs out a specified mass of scrap paper C with the sensorthe supply mechanism supplies it to the downstream merging portion.

Both digital and analog weighing mechanisms can be used as the sensorThe specific mass of scrap paper C weighed by the sensoris, for example, approximately several grams to several tens of grams.

A known technique such as a feeder configured to open and close can be used as the supply mechanism. The supply mechanism may be included in the sensor

The weighing and supplying processes of scrap paper C in the measurement unitare batch processes. Specifically, the supply of scrap paper C from the measurement unitto the merging portionis performed intermittently. The measurement unitmay include a plurality of combinations of the sensorand the supply mechanism, and the plurality of sensorsmay be operated at different timings to improve the weighing and supply efficiency. The sheet manufacturing apparatusincludes two sensorsand supply mechanisms combined with the respective sensors. Thus, scrap paper C is alternately transported from the two sets of sensorsand supply mechanisms to the merging portion.

In the merging portion, shredded slit pieces S supplied from the shredding unitare added to and mixed with the scrap paper C supplied from the measurement unit. The slit pieces S and the shredding unitwill be described later. The scrap paper C mixed with the shredded pieces flows into the pipefrom the merging portion.

The pipetransports scrap paper C from the first set of unitsto the second set of unitsby using a suction airflow generated by a downstream defibrating unit.

The second set of unitsincludes the defibrating unit, which is a dry defibrating machine, a separation unit, a pipe, a supply unit, a mixing unit, and the pipe. In the second set of units, these components are arranged in this order from upstream to downstream. In addition, the second set of unitsalso includes a pipeconnected to the separation unit, a collection unit, a compressor, and a power supply unit.

The scrap paper C transported through the pipeflows into the defibrating unit. The defibrating unitdefibrates the scrap paper C supplied from the measurement unitinto fibers in a dry process. A known defibrating mechanism can be used as the defibrating unit.

The defibrating unithas, for example, the following configuration. The defibrating unitincludes a stator and a rotor. The stator has a substantially cylindrical inner surface. The rotor is disposed inside the stator and rotates along the inner surface of the stator. Small pieces of scrap paper C are pinched between the inner surface of the stator and the rotor and are defibrated by shearing force generated therebetween. This process defibrates entangled fibers included in scrap paper C. The scrap paper C is processed into fibers and transported to the separation unit.

The separation unitseparates the defibrated fibers. Specifically, the separation unitremoves the components unnecessary for manufacturing of sheets P, contained in the fibers. To be specific, the separation unitseparates relatively short fibers from relatively long fibers. Since relatively short fibers can degrade the strength of the sheets P, they are separated by the separation unit. In addition, the separation unitalso separates and removes coloring materials, additives, and the like contained in the scrap paper C. A known technique such as a disk mesh method can be used in the separation unit.

Humidified air is supplied to the inside of the separation unitfrom the second humidification unitin the third set of units.

Relatively short fibers and the like are removed from the defibrated fibers, and the resultant fibers are transported to the mixing unitthrough the pipeby an airflow generated by a blower (not illustrated) disposed at the distal end of an airflow pipe. The unnecessary components such as relatively short fibers and coloring materials are discharged to the collection unitthrough the pipe.

The collection unitincludes a filter (not illustrated). The filter filters out unnecessary components such as relatively short fibers transported through the pipeby the airflow.

The compressorgenerates compressed air. The filter mentioned above can be clogged with fine particles and the like included in the unnecessary components. The filter can be cleaned by blowing the compressed air generated by the compressoronto the filter to blow off adhering particles.

The power supply unitincludes a control unitand a power supply device (not illustrated) that supplies electric power to the sheet manufacturing apparatus. The power supply unitdistributes electric power, which is supplied from the outside, to each component in the sheet manufacturing apparatus. The control unitis electrically connected to each component in the sheet manufacturing apparatusand controls the operation of these components in an integrated manner.

The supply unitsupplies a binder, which is powdered and granular material, to the mixing unit. The mixing unitmixes fibers and the binder supplied from the supply unitin air to form a mixture. The binder is a material that binds fibers to one another in a forming unitdescribed later. In the present embodiment, starch is used as the binder, but the binder is not limited thereto, and a thermoplastic resin or the like may be used.

Note that the powdered and granular material supplied to the mixing unitby the supply unitis not limited to a binder and may be another additive such as a coloring material. The powdered and granular material may be a mixture of a binder and another additive. Furthermore, the sheet manufacturing apparatusmay include a plurality of supply units. Details of the supply unitwill be described later.

Although not illustrated, the mixing unitincludes a flow path and a fan. The flow path of the mixing unitcommunicates with the upstream pipeand the downstream pipe. The supply unitis connected to an intermediate point of the flow path of the mixing unit.

In the mixing unit, fibers flow into the flow path from the pipe. The fan of the mixing unitgenerates an airflow in the flow path. The fibers are transported downstream in the flow path by the airflow of the fan. In this process, the binder supplied from the supply unitinto the flow path is mixed with the fibers. The fibers are mixed with the binder by the airflow mentioned above while being transported in the flow path and form a mixture. The mixture flows into the pipefrom the mixing unit.

The third set of unitsdeposits and compresses the mixture containing fibers to form the belt-like sheet Pwhich is recycled paper. The third set of unitsincludes a deposition unit, a first transportation unit, a second transportation unit, the first humidification unit, the second humidification unit, a drainage unit, and the forming unit.

In the third set of units, the deposition unit, the first transportation unit, the second transportation unit, the first humidification unit, and the forming unitare arranged in this order from upstream to downstream. The second humidification unitis disposed below the first humidification unit.

The deposition unitdeposits the mixture containing the fibers subjected to the separation, in air to form a web W. The deposition unitincludes a drum member, a blade memberdisposed inside the drum member, a housingthat houses the drum member, and a suction unit. The mixture is supplied to the inside of the drum memberthrough the pipe.

The first transportation unitis disposed below the deposition unit. The first transportation unitincludes a mesh beltand five tension rollers (not illustrated) around which the mesh beltis stretched. The suction unitfaces the drum memberwith the mesh beltinterposed therebetween in the Z-axis direction.

The blade memberis disposed inside the drum memberand rotationally driven by a motor (not illustrated). The drum memberis a semi-cylindrical sieve. A mesh having the function of a sieve is provided on the side surface of the drum memberfacing downward. The drum memberallows fibers or particles such as a mixture smaller than the size of the openings of the mesh of the sieve to pass therethrough from the inside to the outside.

The mixture is discharged to the outside of the drum memberwhile being stirred by the rotating blade memberin the drum member. Humidified air is supplied to the inside of the drum memberfrom the second humidification unit.

The suction unitis disposed below the drum member. The suction unitsuctions air inside the housingthrough a plurality of holes of the mesh beltThe plurality of holes of the mesh beltallow air to pass therethrough, but it is difficult for the fibers, the binder, and the like contained in the mixture to pass through the holes. With this configuration, the mixture discharged to the outside of the drum memberis suctioned downward together with air. The suction unitis a known suction device such as a blower.

The mixture is dispersed in the air inside the housingand deposited onto the upper surface of the mesh beltdue to gravity and suction by the suction unitand forms a web W.

The mesh beltis an endless belt, which is stretched around the five tension rollers. The mesh beltis rotated counterclockwise inby the rotation of the tension rollers. Thus, the mixture is continuously deposited onto the mesh beltand forms a web W. The web W contains a relatively large amount of air and is soft and swollen. The first transportation unittransports the formed web W downstream by the rotation of the mesh belt

The second transportation unitis located downstream of the first transportation unitand transports the web W in place of the first transportation unit. The second transportation unitpeels the web W from the upper surface of the mesh beltand transports the web W toward the forming unit. The second transportation unitis located above the transportation path of the web W and slightly upstream of the return start point of the mesh beltThe +Y direction side of the second transportation unitand the −Y direction side of the mesh beltpartially overlap each other in the vertical direction.

The second transportation unitincludes a transportation belt, a plurality of rollers, and a suction mechanism which are not illustrated. The transportation belt has a plurality of holes through which air passes. The transportation belt is stretched around the plurality of rollers and is rotated by the rotation of the rollers.

The second transportation unitcauses the upper surface of the web W to be attracted and attached to the lower surface of the transportation belt by the negative pressure generated by the suction mechanism. The transportation belt rotates in this state, and the web W, attracted and attached to the transportation belt, is transported downstream.

The first humidification unitmoistens the web W containing fibers deposited in the deposition unitof the third set of units. To be specific, the first humidification unitis, for example, a mist humidifier and moistens the web W, which is being transported by the second transportation unit, by supplying mist M to the web W from below. The first humidification unitis disposed below the second transportation unitand faces the web W, which is being transported by the second transportation unit, in the Z-axis direction. For example, a known humidification device such as an ultrasonic humidification device can be used as the first humidification unit.

By moistening the web W with the mist M, a function of starch as a binder is promoted, and the strength of the sheet Pis improved. Since the web W is moistened from below, droplets originating from the mist and falling onto the web W can be prevented. In addition, since the web W is moistened from the side opposite to the contact surface between the transportation belt and the web W, sticking of the web W to the transportation belt is reduced. The second transportation unittransports the web W to the forming unit.