Method of winding optical fiber, method of manufacturing bobbin-wound optical fiber, optical fiber winder, and method of manufacturing optical fiber strand

An optical fiber winder comprising:

• a bobbin mounting portion where a bobbin is mounted, wherein the bobbin comprises:
• a body portion having two end portions;
• and
• a pair of flanges, respectively disposed at the end portions in an axial direction of the body portion, wherein
• an inner surface of each of the flanges is inclined toward an outer side in the axial direction and toward a radial outer side;
• a final pulley that guides an optical fiber to the bobbin;
• and
• a traverse mechanism that relatively reciprocates the bobbin and the final pulley in the axial direction at a traverse speed V (mm/sec), wherein
• the traverse mechanism reciprocates the bobbin or the final pulley such that 0.0050<0 (rad)≤0.1000, where
• θ is a delay angle,
• θ=arctan (V/L), and
• L (mm) is a distance from a winding position of the optical fiber at the bobbin to the final pulley in a radial direction, and
• a path line of the optical fiber wound around the bobbin from the final pulley is inclined to the delay angle θ with respect to a plane perpendicular to a central axis of the bobbin, such that a winding position at which the optical fiber is wound around the bobbin is located in a more rearward position than a separation position at which the optical fiber is separated from the final pulley in a traveling direction that the final pulley travels with respect to the bobbin with the traverse speed V.