Image forming apparatus with an arc-shaped duplex feed path having increased radius of curvature

An image forming apparatus that forms an image on one side of a recording medium by an image forming section and that forms an image on another side of the recording medium by the image forming section, the image forming apparatus comprising:

• a first sheet passing path that transports the recording medium housed in a sheet-feeding tray to the image forming section;
• and
• a second sheet passing path that reverses the recording medium with an image formed on one side and that causes the recording medium to reenter the first sheet passing path via a joining position at which the second sheet passing path meets the first sheet passing path, wherein:
• the first sheet passing path includes, downstream of the joining position in a transport direction of the recording medium, a first interval that transports the recording medium from the joining position in a substantially horizontal direction;
• and
• the second sheet passing path includes, upstream of the joining position:
• an arc-shaped second interval starting at a first spot to reverse the recording medium and to transport the recording medium in a reversed state to the joining position;
• a third interval starting at a second spot and ending at the first spot to transport the recording medium obliquely downwardly to the second interval;
• and
• a fourth interval starting at a third spot and ending at the second spot to transport the recording medium substantially horizontally to the third interval, the fourth interval including transport rollers at both ends at the third spot and the second spot, respectively, wherein
• the first spot at which the third interval ends and the second interval starts is located at a lowest portion of the second sheet passing path in a vertical direction,
• a first distance between a level of the third spot and the first spot is shorter than a second distance between the level of the third spot and a lowest portion of the transport roller at the third spot, the lowest portion of the transport roller at the third spot defining a lowermost limit of all transport rollers included in the second sheet passing path, and
• at least a part of the fourth interval is above the sheet-feeding tray.

An image forming apparatus that forms an image on one side of a recording medium by an image forming section and that forms an image on another side of the recording medium by the image forming section, the image forming apparatus comprising:

• a first sheet passing path that transports the recording medium housed in a sheet-feeding tray to the image forming section;
• and
• a second sheet passing path that reverses the recording medium with an image formed on one side and that causes the recording medium to reenter the first sheet passing path via a joining position at which the second sheet passing path meets the first sheet passing path, wherein:
• the first sheet passing path includes a first interval that transports the recording medium in a substantially horizontal direction from the joining position to a placement position of the image forming section in a transport direction of the recording medium;
• and
• the second sheet passing path includes:
• an arc-shaped second interval starting at a first spot to reverse the recording medium and to transport the recording medium in a reversed state to the joining position;
• a third interval starting at a second spot and ending at the first spot to transport the recording medium obliquely downwardly to the second interval;
• and
• a fourth interval starting at a third spot and ending at the second spot to transport the recording medium substantially horizontally to the third interval, the fourth interval including transport rollers at both ends at the third spot and the second spot, respectively, wherein
• the first spot at which the third interval ends and the second interval starts is located at a lowest portion of the second sheet passing path in a vertical direction,
• a first distance between a level of the third spot and the first spot is shorter than a second distance between the level of the third spot and a lowest portion of the transport roller at the third spot, the lowest portion of the transport roller at the third spot defining a lowermost limit of all transport rollers included in the second sheet passing path, and
• at least a part of the fourth interval is above the sheet-feeding tray.