A method for screening an optical fiber core including a resin coating layer, includes: a pre-strain applying step of adding a tensile force while feeding a portion of the optical fiber core retained at both ends of the portion, and applying a pre-tensile strain larger than zero and smaller than a guaranteed tensile strain set as a guaranteed value; a guaranteed strain applying step of adding a tensile force while feeding the portion of the optical fiber core retained at both ends of the portion and applied with the pre-tensile strain, and applying the guaranteed tensile strain only for a predetermined time; and a guaranteed strain releasing step of releasing the optical fiber core from the guaranteed tensile strain.

A method for screening an optical fiber core including a resin coating layer, includes: a pre-strain applying step of adding a tensile force while feeding a portion of the optical fiber core retained at both ends of the portion, and applying a pre-tensile strain larger than zero and smaller than a guaranteed tensile strain set as a guaranteed value; a guaranteed strain applying step of adding a tensile force while feeding the portion of the optical fiber core retained at both ends of the portion and applied with the pre-tensile strain, and applying the guaranteed tensile strain only for a predetermined time; and a guaranteed strain releasing step of releasing the optical fiber core from the guaranteed tensile strain.

Addressed is the object of improving an unwinding performance of a glass direct roving at an end surface. A method of manufacturing a glass direct roving includes winding a glass strand into a cylindrical shape while traversing the glass strand. In the winding, the glass strand is wound traversing the glass strand under the conditions that a wind order of the crosswindng is or greater, and an interval parameter, which is the smaller value among “b” and “A−b”, is from “(A/2)*−(A/4)*” to “(A/2)*−1”, where “A” is the wind order, “(A/2)*” is a maximum integer no greater than ½ the wind order, “(A/4)*” is a maximum integer no greater than ¼ the wind order, and a mixed fraction “a+(b/A)” is used to express a cyclewind of the crosswindng.

Provided is a screening apparatus or the like of an optical fiber that can suppress or prevent occurrence of a fiber-strike on the side of a feeding bobbin regardless of the weight of the feeding bobbin. An embodiment has a feeding bobbin 12 that feeds out an optical fiber 10; a screening unit 16 that applies a tension to the optical fiber 10 fed out from the feeding bobbin 12; a first capstan 14 that feeds the optical fiber 10 into the screening unit 16; a winding bobbin 20 that winds the optical fiber 10 to which the tension is applied by the screening unit 16; and a control unit 70 that, when disconnection of the optical fiber 10 occurs due to the tension applied by the screening unit 16, controls the feeding bobbin 12 and the first capstan 14 so as to stop rotation of the feeding bobbin 12 and rotation of the first capstan 14 and sets a deceleration rate of the first capstan 14 in accordance with a deceleration rate of the feeding bobbin 12.

Provided is a screening apparatus or the like of an optical fiber that can suppress or prevent occurrence of a fiber-strike on the side of a feeding bobbin regardless of the weight of the feeding bobbin. An embodiment has a feeding bobbin 12 that feeds out an optical fiber 10; a screening unit 16 that applies a tension to the optical fiber 10 fed out from the feeding bobbin 12; a first capstan 14 that feeds the optical fiber 10 into the screening unit 16; a winding bobbin 20 that winds the optical fiber 10 to which the tension is applied by the screening unit 16; and a control unit 70 that, when disconnection of the optical fiber 10 occurs due to the tension applied by the screening unit 16, controls the feeding bobbin 12 and the first capstan 14 so as to stop rotation of the feeding bobbin 12 and rotation of the first capstan 14 and sets a deceleration rate of the first capstan 14 in accordance with a deceleration rate of the feeding bobbin 12.

A method for screening an optical fiber core including a resin coating layer, includes: a pre-strain applying step of adding a tensile force while feeding a portion of the optical fiber core retained at both ends of the portion, and applying a pre-tensile strain larger than zero and smaller than a guaranteed tensile strain set as a guaranteed value; a guaranteed strain applying step of adding a tensile force while feeding the portion of the optical fiber core retained at both ends of the portion and applied with the pre-tensile strain, and applying the guaranteed tensile strain only for a predetermined time; and a guaranteed strain releasing step of releasing the optical fiber core from the guaranteed tensile strain.

A method for screening an optical fiber core including a resin coating layer, includes: a pre-strain applying step of adding a tensile force while feeding a portion of the optical fiber core retained at both ends of the portion, and applying a pre-tensile strain larger than zero and smaller than a guaranteed tensile strain set as a guaranteed value; a guaranteed strain applying step of adding a tensile force while feeding the portion of the optical fiber core retained at both ends of the portion and applied with the pre-tensile strain, and applying the guaranteed tensile strain only for a predetermined time; and a guaranteed strain releasing step of releasing the optical fiber core from the guaranteed tensile strain.

An optical fiber manufacturing device including a guide roller mechanism configured to bring a traveling optical fiber into contact with a predetermined groove to guide the traveling optical fiber. The guide roller mechanism includes a plurality of guide roller bodies each of which is configured to be rotated and configured to guide a traveling optical fiber, and a guide roller rotation shaft fixing mechanism configured to rotatably support rotation shafts of at least two guide roller bodies among the plurality of guide roller bodies. The guide roller rotation shaft fixing mechanism includes a position adjustment mechanism configured to adjust, for each of the rotation shafts, a horizontal two-axis position of a horizontal plane including an axial direction, and an angle adjustment mechanism configured to adjust an inclination angle of each of the rotation shafts.

An optical fiber manufacturing device including a guide roller mechanism configured to bring a traveling optical fiber into contact with a predetermined groove to guide the traveling optical fiber. The guide roller mechanism includes a plurality of guide roller bodies each of which is configured to be rotated and configured to guide a traveling optical fiber, and a guide roller rotation shaft fixing mechanism configured to rotatably support rotation shafts of at least two guide roller bodies among the plurality of guide roller bodies. The guide roller rotation shaft fixing mechanism includes a position adjustment mechanism configured to adjust, for each of the rotation shafts, a horizontal two-axis position of a horizontal plane including an axial direction, and an angle adjustment mechanism configured to adjust an inclination angle of each of the rotation shafts.

Provided is a screening apparatus or the like of an optical fiber that can suppress or prevent occurrence of a fiber-strike on the side of a feeding bobbin regardless of the weight of the feeding bobbin. An embodiment has a feeding bobbin 12 that feeds out an optical fiber 10; a screening unit 16 that applies a tension to the optical fiber 10 fed out from the feeding bobbin 12; a first capstan 14 that feeds the optical fiber 10 into the screening unit 16; a winding bobbin 20 that winds the optical fiber 10 to which the tension is applied by the screening unit 16; and a control unit 70 that, when disconnection of the optical fiber 10 occurs due to the tension applied by the screening unit 16, controls the feeding bobbin 12 and the first capstan 14 so as to stop rotation of the feeding bobbin 12 and rotation of the first capstan 14 and sets a deceleration rate of the first capstan 14 in accordance with a deceleration rate of the feeding bobbin 12.