Sheet Manufacturing Apparatus

The present application is based on, and claims priority from JP Application Serial Number 2024-069547, 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.

WO 2018/043030 discloses a sheet manufacturing apparatus including a defibrating portion, a web forming portion, a sheet forming portion, a cutter portion, and a control portion. The defibrating portion defibrates a raw material containing fibers in the atmosphere. The web forming portion forms a web by accumulating the defibrated material defibrated by the defibrating portion. The sheet forming portion forms a sheet from the web formed by the web forming portion. The cutter portion cuts the sheet formed by the sheet forming portion to a preset size. When the operation of the apparatus is stopped, the control portion optimizes the order or timing of stopping the operation of each portion.

In the sheet manufacturing apparatus of WO 2018/043030, mechanisms of each portion that performs each process such as defibration, accumulation, sheet forming, and sheet cutting are interlocked with each other. For example, when the operation of the apparatus is stopped due to an occurrence of a transport failure of a defibrated material, a web, a sheet, or the like, a material or goods in progress, of which the residual amount is unknown, remains in each portion although the process or timing of stopping the operation of each portion is optimized. Therefore, in the sheet manufacturing apparatus of WO 2018/043030, there is a concern that it takes time to restart the apparatus after the operation of the apparatus is stopped due to an abnormality in the transport of the sheet or the like. In addition, there is a possibility that a service man needs to respond to the restart after the operation of the apparatus is stopped.

According to an aspect of the present disclosure, a sheet manufacturing apparatus includes a sheet forming unit that forms a sheet by accumulating a material containing fibers and then compressing the accumulated material, and a transport unit that transports the sheet along a transport path, in which the transport unit includes a plurality of transport rollers that transport the sheet, an abnormality detection sensor that detects an abnormality generated in transport of the sheet in the transport unit, a cover that is installed above the transport path and is configured to rotate around a shaft of a rotation shaft, and a drive motor that rotates the cover by being rotationally driven, the cover moves between an open position that opens an upper portion of the transport path and a closed position that covers the upper portion of the transport path, and the cover moves from the closed position to the open position by the drive motor being rotationally driven when the abnormality detection sensor detects an abnormality generated in the transport of the sheet.

The following embodiment exemplifies a sheet manufacturing apparatusthat regenerates a sheet from a material containing fibers, such as waste paper, in a dry manner as a sheet manufacturing apparatus of the present disclosure. Hereinafter, the sheet manufacturing apparatuswill be described with reference to the drawings. The sheet manufacturing apparatus of the present disclosure is not limited to a dry type, and may be a wet type. In the present specification, the dry type means that it is carried out in the air, such as the atmosphere, not in the liquid.

In each figure, the same members are designated by the same reference numerals, and redundant descriptions will be omitted. The terms, “same”, “identical”, and “simultaneous” in the case described in the present specification do not refer to being completely the same. For example, in the present specification, when it is described as “same”, “identical”, and “simultaneous”, it is assumed that a case where it is the same in consideration of a measurement error is included. In addition, for example, in the present specification, when it is described as “same”, “identical”, and “simultaneous”, it is assumed that a case where it is the same in consideration of manufacturing variations of members is included.

In the present specification, when it is described as “same”, “identical”, or “simultaneous”, it is assumed that a case where it is the same in a range in which a function is not impaired is included. Therefore, for example, “the dimensions of both are the same” means that the difference in dimensions between the two is within +5% of one dimension, particularly preferably within +3% in consideration of a measurement error and manufacturing variations of members.

In each of the drawings, X, Y, and Z represent three spatial axes that are orthogonal to each other. In the present specification, the directions along these axes are referred to as an X-axis direction, a Y-axis direction, and a Z-axis direction. When specifying the direction, the positive direction is “+”, the negative direction is “−” and by using the positive and negative signs together in the direction notation, the direction in which the arrow points in each figure will be described as the + direction, and the direction opposite to the arrow will be described as the − direction.

The Z-axis direction indicates a gravity direction, the +Z direction indicates a vertically upward direction, and the −Z direction indicates a vertically downward direction. A plane including the X-axis and the Y-axis is described as an X-Y plane, a plane including the X-axis and the Z-axis is described as an X-Z plane, and a plane including the Y-axis and the Z-axis is described as a Y-Z plane. The X-Y plane is a horizontal plane. The three X, Y, and Z spatial axes that do not limit the positive direction and the negative direction will be described as the X-axis, the Y-axis, and the Z-axis.

The X-axis direction is a horizontal direction along an installation surface, which is a horizontal plane, on which the sheet manufacturing apparatusis installed. The Y-axis direction is the horizontal direction along the installation surface on which the sheet manufacturing apparatusis installed. The Z-axis direction is a normal direction with respect to the installation surface on which the sheet manufacturing apparatusis installed, and is a height direction of the sheet manufacturing apparatus.

In the following description, the +Z direction may be referred to as an “upward direction”, and the −Z direction may be referred to as a “downward direction”. In the following description, in the sheet manufacturing apparatus, the front in a transport direction of a raw material, a web W, sheets P, P, and P, or the like may be referred to as “downstream”, and the side going upstream in the transport direction may be referred to as “upstream”. For convenience of illustration, the size of each member is different from the actual size.

As illustrated in, the sheet manufacturing apparatusaccording to the present embodiment includes a first unit group, a second unit group, and a third unit group. The first unit group, the second unit group, and the third unit groupare supported by a frame (not illustrated).

In, directions, in which a paper piece C, a sheet P, slit pieces S, an unnecessary end material, or the like moves, are indicated by white arrows. In the following description, a set of the paper pieces C composed of a plurality of paper pieces C is also simply referred to as the paper piece C.

The sheet manufacturing apparatusmanufactures the sheet Pfrom the paper piece C that is a material containing fibers such as waste paper. The paper piece C is an example of a raw material. In a side view from the −X direction, in the sheet manufacturing apparatus, the first unit group, the third unit group, and the second unit groupare disposed from the −Y direction to the +Y direction.

According to the sheet manufacturing apparatusof the present embodiment, since the sheet Pcan be manufactured from the paper piece C, the discarded amount of the paper piece C is reduced by recycling the paper piece C. Therefore, the sheet manufacturing apparatusof the present embodiment can contribute to the achievement of sustainable development goals (SDGs) such as Target“To ensure sustainable consumption and production patterns”.

The paper piece C is transported from the first unit groupto the second unit groupvia a pipecrossing an inside of the third unit group. Then, the paper piece C is formed of fibers by performing defibration or the like in the second unit group, and is a mixture containing a binder or the like. The mixture is transported to the third unit groupvia a pipe. The mixture is formed into the band-shaped sheet Pafter being formed into the web W by the third unit group. The band-shaped sheet Pis cut by the first unit groupto form the sheet P.

The first unit groupincludes a raw material supply device, a measurement portion, a merging portion, and the pipe. In the first unit group, the configurations thereof are disposed in the above order from the upstream to the downstream. In addition, the first unit groupalso includes a downstream transport unitof a transport unit, a tray, and a shredding portion.

The downstream transport unithas a first cutting portionand a second cutting portion. The first cutting portioncuts the band-shaped sheet Pinto the cut-shaped sheet P. The second cutting portioncuts the cut-shaped sheet Pinto a sheet Phaving a predetermined shape. The first cutting portionand the second cutting portionare examples of a cutter.

The first unit grouphas a water supply portion. The water supply portionis a water storage tank. The water supply portionsupplies water for humidification to each of a first humidification portionand a second humidification portion(to be described later) through a water supply pipe (not illustrated).

The raw material supply devicestores the paper piece C, which is the raw material of the sheet P, and supplies the paper piece C to the downstream. The raw material supply deviceincludes a raw material inlet, a storage portion, and a discharge portion.

The paper piece C is charged from the raw material inletinto the storage portion. The paper piece C contains fibers such as cellulose, and is, for example, shredded waste paper. Inside the storage portion, humidified air is supplied from a second humidification portionincluded in the third unit group.

The paper piece C is temporarily stored in the storage portionand then transported to the measurement portionvia the discharge portion. The sheet manufacturing apparatusmay include a shredder that shreds the paper piece C or the like on the upstream of the storage portion.

The measurement portionincludes a sensor portionand a supply mechanism (not illustrated). The sensor portionmeasures the mass of the paper piece C. The supply mechanism supplies the paper piece C weighed by the sensor portionto the downstream merging portion. That is, the measurement portionweighs the paper piece C by the sensor portionfor each predetermined mass, and supplies the paper piece C to the downstream merging portionby the supply mechanism.

Any of the digital type and the analog type weighing mechanisms can be applied to the sensor portion. Specifically, examples of the sensor portioninclude a physical sensor such as a load cell, and a spring scale or a balance, or the like. In the present embodiment, a load cell is applied as the sensor portion. The predetermined mass of the paper piece C weighed by the sensor portionis, for example, several g to several tens of g.

A feeder that can be opened and closed or the like can be applied to the supply mechanism. The supply mechanism may be configured to be included in the sensor portion

The weighing and supply of the paper piece C by the measurement portionare batch processing. That is, the supply of the paper piece C from the measurement portionto the merging portionis intermittently performed. The measurement portionmay have a plurality of combinations of the sensor portionand the supply mechanism, and may improve the efficiency of weighing and supply by causing the plurality of sensor portionsto operate in time differences.

The sheet manufacturing apparatusincludes the two sensor portionsand the supply mechanisms respectively attached to the sensor portions. As a result, the paper piece C is alternately transported to the merging portionfrom two sets of the sensor portionsand the supply mechanisms.

In the merging portion, the shredded pieces of the slit pieces S, which are supplied from the shredding portion, are merged and mixed with the paper piece C supplied from the measurement portion. The slit pieces S and the shredding portionwill be described later. The paper piece C in which the above shredded pieces are mixed flows from the merging portioninto the pipe.

The pipetransports the paper piece C from the first unit groupto the second unit groupby a suction airflow generated by a downstream defibrating portion.

The second unit groupincludes the defibrating portion, a separation portion, a pipe, a mixing portion, and a pipe, which are a dry-type defibrating machine. In the second unit group, the configurations thereof are disposed in the above order from the upstream to the downstream. The second unit groupalso includes a pipecoupled to the separation portion, a collection portion, a compressor, and a power supply portion.

The paper piece C transported through the pipeflow into the defibrating portion. The defibrating portiondefibrates the paper piece C supplied from the measurement portionin a dry manner to form fibers. A defibrating mechanism using a rotating rotor, or the like can be applied to the defibrating portion.

Since the defibrating portionof the present embodiment defibrates the paper piece C in a dry manner to form fibers, the usage amount of water and the discharged amount of water can be reduced as compared with a wet defibrating method of defibrating in water. Therefore, the defibrating portionof the present embodiment can contribute to the achievement of the SDGs such as Target“To ensure access to water and sanitation for all and sustainable management”. The defibrating portionof the present embodiment can contribute to the achievement of the SDGs such as Target“To conserve and sustainably use the ocean and marine resources for sustainable development”.

According to the defibrating portionof the present embodiment, since it is not necessary to dry a defibrated material, the generated amount of carbon dioxide in the process of defibrating the paper piece C can be reduced. Therefore, the defibrating portionof the present embodiment can contribute to the achievement of the SDGs such as Target“To take urgent measures to address climate change and its impacts”.

Examples of the configuration of the defibrating portioninclude the following. The defibrating portionincludes a stator and a rotor. The stator has a substantially cylindrical inner surface. The rotor is installed inside the stator and rotates along the inner surface of the stator. The paper piece C is interposed between the inner surface of the stator and the rotor, and is defibrated by a shear force generated between the stator and the rotor. As a result, in the paper piece C, the entangled fibers included in the paper piece are unraveled. The paper piece C is transported to the separation portionas fibers.

The separation portionsorts the defibrated fibers. Specifically, the separation portionremoves the unnecessary components for manufacturing the sheet P, which is included in the fiber. Specifically, the separation portionsorts the relatively long fibers and the relatively short fibers. The relatively short fibers are sorted by the separation portionbecause the relatively short fibers may cause a decrease in strength of the sheet P. In addition, the separation portionalso sorts and eliminates coloring materials, additives, or the like included in the paper piece C. A technique such as a disc mesh method can be applied to the separation portion.

The air humidified by the second humidification portionof the third unit groupis supplied into an inside of the separation portion.

The defibrated fibers are transported to the mixing portionvia the pipeafter relatively short fibers or the like are eliminated. The unnecessary components such as relatively short fibers and coloring materials are discharged to the collection portionvia the pipe.

The mixing portionmixes the defibrated material with a binder or the like in the air to form a mixture. Although not illustrated, the mixing portionincludes a flow path through which the defibrated material is transported, a fan, a hopper, a supply pipe, and a valve.

The hopper communicates with a flow path of the defibrated material via the supply pipe. The valve is provided in the supply pipe between the hopper and the flow path. The hopper supplies a binder such as starch into the flow path. The valve adjusts the mass of the binder supplied from the hopper to the flow path. As a result, a mixing ratio of the fiber and the binder is adjusted.

The mixing portionmay have a similar configuration for supplying coloring materials, additives, or the like in addition to the configuration for supplying the binder.

The fan of the mixing portionmixes the defibrated material with the binder or the like in the air when the defibrated material including the fibers is transported to the downstream by an airflow to be generated, to form a mixture. The mixture flows from the mixing portioninto the pipe.

The collection portionincludes a filter (not illustrated). The filter filters out unnecessary components such as relatively short fibers transported by the airflow from the pipe.

The compressorgenerates compressed air. In the above filter, clogging may occur due to fine particles or the like in the unnecessary components. The compressed air generated by the compressorcan be blown onto the filter to blow off adhered particles and clean the filter.

The power supply portionincludes a control portionand a power supply device (not illustrated) that supplies power to the sheet manufacturing apparatus. The power supply portiondistributes the power supplied from the outside to each configuration of the sheet manufacturing apparatus.

The control portionincludes a central processing unit (CPU) although not illustrated. The control portionincludes a storage portion including a random access memory (RAM), a read only memory (ROM), or the like. Various programs for controlling the sheet manufacturing apparatusare stored in the storage portion.

The control portionmay include one or more processors that execute various processing according to a program, one or more dedicated hardware circuits such as an application specific integrated circuit (ASIC), or a combination thereof. The application-specific integrated circuit (ASIC) executes at least some of various processes.

The processor includes a CPU and a memory such as a RAM and a ROM. The memory stores program codes or instructions configured to cause the CPU to execute processing. A memory, that is, a computer-readable medium, includes anything accessible by a general-purpose or dedicated computer.

The control portionis electrically coupled to each configuration such as a sheet forming unitand the transport unit, which will be described later, and integrally controls the operation of these configurations.

In particular, the control portioninstructs the countermeasure for each configuration when the transport abnormality of the cut-shaped sheet Por the like occurs in the transport path. Details of the above countermeasures will be described later.