Sheet manufacturing apparatus

A sheet manufacturing apparatus comprising:

• a defibrator that defibrates a material containing a fiber and generates a defibrated material;
• a accumulating portion that forms a web by accumulating the defibrated material;
• and
• a sheet shaping portion that includes a first roller and a second roller, and forms a sheet by pressing the web, wherein
• the sheet shaping portion includes
• a first roller retention unit at which the first roller is installed,
• a drive motor that is configured to be rotated in a forward direction and a reverse direction,
• a second roller gear that receives transmission of rotation of the drive motor and rotates the second roller,
• a first transmission gear that receives transmission of rotation of the second roller gear,
• a one-way clutch gear installed at a rotating shaft common to the first transmission gear,
• a cam gear that receives transmission of rotation of the one-way clutch gear,
• a cam installed coaxially with the cam gear, and
• a pin that is fixed to the first roller retention unit and performs positioning of the first roller retention unit by coming into contact with the cam, and
• the first transmission gear includes an idling mechanism configured to run idle over a certain period.