A sheet manufacturing system includes a sheet manufacturing apparatus that decomposes a document, and a server apparatus that manages a process status of the document, in which the sheet manufacturing apparatus includes a read unit that reads identification information attached to the document, a processing unit that decomposes the document the identification information of which was read by the read unit and that is determined to be suitable for a decomposing process, a determination unit that determines that the document was decomposed by the processing unit, and a first communication unit that transmits to the server apparatus the identification information of the document determined by the determination unit to have been decomposed by the processing unit.

A web forming device includes: a defibrator having a variable speed rotor, and configured to defibrate defibration feedstock by rotation of the rotor; an accumulator on which defibrated material defibrated by the defibrator accumulates; a thickness detector configured to detect a thickness of the defibrated material accumulated on the accumulator; and a controller configured to control a rotational velocity of the rotor based on a detection result from the thickness detector. The controller applies either or both a first control and a second control, the first control decreasing the rotational velocity of the rotor when variation in the thickness of the deposited defibrated material detected by the thickness detector exceeds a first tolerance, and the second control increasing the rotational velocity of the rotor when a slope of change over time in a thickness of the deposited defibrated material detected by the thickness detector is less than a second tolerance.

A web forming device includes: a defibrator having a variable speed rotor, and configured to defibrate defibration feedstock by rotation of the rotor; an accumulator on which defibrated material defibrated by the defibrator accumulates; a thickness detector configured to detect a thickness of the defibrated material accumulated on the accumulator; and a controller configured to control a rotational velocity of the rotor based on a detection result from the thickness detector. The controller applies either or both a first control and a second control, the first control decreasing the rotational velocity of the rotor when variation in the thickness of the deposited defibrated material detected by the thickness detector exceeds a first tolerance, and the second control increasing the rotational velocity of the rotor when a slope of change over time in a thickness of the deposited defibrated material detected by the thickness detector is less than a second tolerance.

Provided are a shredder assuring greater freedom in designing a feedstock supplier that supplies sheets, and a sheet manufacturing apparatus. The shredder has a feedstock supplier having a supply opening through which a sheet is supplied; and a shredding device configured to shred the sheet supplied from the feedstock supplier. The shredding device includes a rotary cutter that rotates on a first axis, and a circulating cutter that moves in an endless path and cuts the sheet in conjunction with the rotary cutter. The circulating cutter includes a conveyor configured to convey the sheet from the feedstock supplier to the rotary cutter.

Provided are a shredder assuring greater freedom in designing a feedstock supplier that supplies sheets, and a sheet manufacturing apparatus. The shredder has a feedstock supplier having a supply opening through which a sheet is supplied; and a shredding device configured to shred the sheet supplied from the feedstock supplier. The shredding device includes a rotary cutter that rotates on a first axis, and a circulating cutter that moves in an endless path and cuts the sheet in conjunction with the rotary cutter. The circulating cutter includes a conveyor configured to convey the sheet from the feedstock supplier to the rotary cutter.

A coarse crushing device including a rotary cutter portion tearing off a fiber-containing sheet in a first direction, a roller portion pinching the fiber-containing sheet, and a tearing portion provided between the rotary cutter portion and the roller portion, and having a plurality of blades tearing off the fiber-containing sheet in a second direction intersecting the first direction, in which the rotary cutter portion includes a first rotating shaft member rotating about a first axis, a second rotating shaft member rotating reversely to the first rotating shaft member about a second axis parallel to the first axis, a plurality of first rotary cutters provided on the first rotating shaft member and rotating together with the first rotating shaft member, and a plurality of second rotary cutters provided on the second rotating shaft member and rotating together with the second rotating shaft member, and the first rotary cutter and the second rotary cutter are separated from each other.

A defibrating device and sheet manufacturing apparatus attract and remove metal fragments when metal fragments are mixed with fibrous material. A defibrating device has a main unit with a defibration section configured to defibrate fibrous material, and a swirl section configured to produce a rotational current, and by the rotational current cause the fibrous material to rotate and flow into the defibration section. The main unit has a magnet unit that is disposed to the swirl section, and has a magnet that attracts by magnetic force metal fragments conveyed with the fibrous material to the swirl section.

A defibrating device and sheet manufacturing apparatus attract and remove metal fragments when metal fragments are mixed with fibrous material. A defibrating device has a main unit with a defibration section configured to defibrate fibrous material, and a swirl section configured to produce a rotational current, and by the rotational current cause the fibrous material to rotate and flow into the defibration section. The main unit has a magnet unit that is disposed to the swirl section, and has a magnet that attracts by magnetic force metal fragments conveyed with the fibrous material to the swirl section.

A raw material supply device includes a housing that stores an aggregate of small pieces, a discharge port through which the small pieces are discharged from an inside of the housing, a rotor provided in the housing and including a protruding portion, and a magnet provided on the discharge port or on a downstream side of the discharge port. In addition, it is preferable that the raw material supply device further include a passage route that communicates with the discharge port and through which the small pieces pass, in which at least one pair of the magnets is disposed on one side and the other side via the passage route.

A raw material supply device includes a housing that stores an aggregate of small pieces, a discharge port through which the small pieces are discharged from an inside of the housing, a rotor provided in the housing and including a protruding portion, and a magnet provided on the discharge port or on a downstream side of the discharge port. In addition, it is preferable that the raw material supply device further include a passage route that communicates with the discharge port and through which the small pieces pass, in which at least one pair of the magnets is disposed on one side and the other side via the passage route.