Abstract: An optical fiber unit includes: a plurality of optical fibers; and at least two binding materials that bind the plurality of optical fibers. The two binding materials are wound around the plurality of optical fibers in an SZ shape and adhered to each other at reversed portions of the SZ shape to form an adhesive part. The adhesive part extends along a longitudinal direction where the optical fiber unit extends, and 0.15?L/(P/2)?0.8 is satisfied where L is a length of the adhesive part in the longitudinal direction and P is a binding pitch of the two binding materials in the longitudinal direction.

Abstract: An optical fiber unit includes a plurality of optical fibers; and two binding materials that bind the optical fibers. The two binding materials are wound around the optical fibers in an SZ shape, and are adhered to each other at respective reversed portions that form an adhesive part. The adhesive part has a plurality of intersection points of center lines of the two binding materials.

Abstract: An optical fiber unit includes a plurality of optical fibers; and two binding materials that bind the optical fibers. The two binding materials are wound around the optical fibers in an SZ shape, and are adhered to each other at respective reversed portions that form an adhesive part. The adhesive part has a plurality of intersection points of center lines of the two binding materials.

Abstract: An optical fiber colored core wire includes: a bare optical fiber; a primary layer that comprises a UV curable resin that covers the bare optical fiber; a secondary layer that comprises a UV curable resin that covers the primary layer; and a colored layer disposed outside the secondary layer and that comprises a colored UV curable resin. The primary layer has a Young's modulus that is greater than or equal to 70% of a saturated Young's modulus of the primary layer.

Abstract: An optical fiber ribbon is formed by connecting a plurality of optical fiber colored core wires to each other with a connector formed of a UV curable resin. Each of the optical fiber colored core wires includes: a bare optical fiber; a primary layer that comprises a UV curable resin that covers the bare optical fiber; a secondary layer that comprises a UV curable resin that covers the primary layer; and a colored layer disposed outside the secondary layer and that comprises a colored UV curable resin. The primary layer has a Young's modulus that is greater than or equal to 75% of a saturated Young's modulus of the primary layer.

Abstract: An optical fiber cable includes: a core; a sheath that accommodates the core therein; and a pair of tension members embedded in the sheath. The core includes: a plurality of optical fiber units that each includes a plurality of optical fibers; fibrous fillings that extend in a longitudinal direction in which the plurality of optical fiber units extends; and a wrapping tube that encloses the plurality of optical fiber units and the fibrous fillings. The core is interposed between the pair of tension members.

Abstract: An inspection device of an optical fiber unit, including a plurality of binding materials wound in an SZ shape on a plurality of optical fibers, includes: a measurement sensor that measures a width of the optical fiber units in a first direction orthogonal to a longitudinal direction in which the optical fiber unit extends; and a determination circuit that determines a presence or an absence of an abnormality in a binding state, based on a measurement result of the measurement sensor.

Abstract: A method for producing an optical fiber unit by winding at least two bundling members on the outer circumference of an optical fiber bundle formed by bundling a plurality of optical fibers, including: feeding the optical fiber bundle from a fiber passage member; feeding the bundling members while forming intersection points between two of the bundling members on the outer circumference of the optical fiber bundle by feeding at least one of the bundling members from a bundling member passage part of a rotating member arranged to the outer circumference of the fiber passage member, while causing the rotating member to oscillate, with the feeding direction serving as the axis; and fusion-bonding the bundling members at their intersection points.

Abstract: An optical fiber unit includes: a plurality of optical fibers; and at least two binding materials that bind the plurality of optical fibers. The two binding materials are wound around the plurality of optical fibers in an SZ shape and adhered to each other at reversed portions of the SZ shape to form an adhesive part. The adhesive part extends along a longitudinal direction where the optical fiber unit extends, and 0.15?L/(P/2)?0.8 is satisfied where L is a length of the adhesive part in the longitudinal direction and P is a binding pitch of the two binding materials in the longitudinal direction.

Abstract: An optical fiber unit includes a plurality of optical fibers; and two binding materials that bind the optical fibers. The two binding materials are wound around the optical fibers in an SZ shape, and are adhered to each other at respective reversed portions that form an adhesive part. The adhesive part has a plurality of intersection points of center lines of the two binding materials.

Abstract: An optical fiber cable is provided. The cable includes: an optical fiber core having a central axis; a presser winding covering the optical fiber core; a sheath covering the presser winding; two tension members in the sheath and facing each other with the central axis therebetween; and two rip cords facing each other with the central axis therebetween and being in direct contact with the sheath and the presser winding. The optical fiber core includes a plurality of optical fiber tapes arranged around the central axis and having mutually different stripe ring marks applied thereon. Each optical fiber tapes includes a plurality of optical fibers intermittently adhered to each other.

Abstract: A former including: a guide pipe guiding an optical fiber bundle; a tape forming section forming a press-wrapping tape from a strip shape into a helical shape, while guiding the press-wrapping tape along a feed direction, the tape forming section including a curved section gradually curving the strip shaped press-wrapping tape while guiding the press-wrapping tape along the feed direction, and a helical section that is a helical tube shaped location further to a downstream side than a position where two edges of the curved section intersect with each other, the helical section causing two end portions of the press-wrapping tape that has been curved with the curved section to overlap and forming the press-wrapping tape into a helical shape, while guiding the press-wrapping tape along the feed direction, and gradually narrowing an external diameter of the helical shaped press-wrapping tape.

Abstract: Provided are a method and an apparatus for extruding into a tube and filling the tube at a high speed and simultaneously sealing the tube. Specifically provided is a method for producing a polymer tube, containing a liquid therein and being sealed at constant intervals, the method including an extrusion step of continuously melt-extruding a polymer material through a die into at least one tube, while feeding a liquid into the tube to obtain at least one liquid-containing tube; and sealing step of discontinuously pressing the at least one liquid-containing tube between a pair of pressurizing members at constant intervals to cause pressure-bonding before the tube solidifies, while continuously taking up the extruded tube.

Abstract: [Problem] The thickness on a ripcord in a circular optical cable is reduced, to improve workability. [Solution] An optical cable of the present invention includes: an optical fiber unit including optical fibers; a sheath, having a circular external form, configured to house the optical fiber unit in a housing portion; and two strength members embedded in the sheath; and two rip cords, wherein when a direction of connecting the two strength members sandwiching the housing portion is a first direction and a direction intersecting the first direction is a second direction, in a cross section of the optical cable, a cross-sectional shape of the housing portion has a dimension in the second direction greater than that in the first direction, and the two rip cords is disposed to sandwich the optical fiber unit such that a direction of connecting the two rip cords is in the second direction, in the cross section of the optical cable.

Abstract: An optical fiber unit includes: an optical fiber bundle formed by bundling a plurality of optical fibers; and a plurality of bundling members. Each of the bundling members is wound on an outer circumference of the optical fiber bundle along a length direction of the optical fiber bundle while a winding direction of the bundling member is reversed alternately, and joined with another bundling member at reverse sections where the winding direction of the bundling member is reversed. A region surrounded by a pair of the bundling members to be joined at the reverse sections includes a joining point at one of the reverse sections of another pair of the bundling members.

Abstract: An optical fiber unit includes: an optical fiber bundle formed by bundling a plurality of optical fibers; and a plurality of bundling members. Each of the bundling members is wound on an outer circumference of the optical fiber bundle along a length direction of the optical fiber bundle while a winding direction of the bundling member is reversed alternately, and joined with another bundling member at reverse sections where the winding direction of the bundling member is reversed. A region surrounded by a pair of the bundling members to be joined at the reverse sections includes a joining point at one of the reverse sections of another pair of the bundling members.

Abstract: An optical fiber cable is provided. The cable includes: an optical fiber core having a central axis; a presser winding covering the optical fiber core; a sheath covering the presser winding; two tension members in the sheath and facing each other with the central axis therebetween; and two rip cords facing each other with the central axis therebetween and being in direct contact with the sheath and the presser winding. The optical fiber core includes a plurality of optical fiber tapes arranged around the central axis and having mutually different stripe ring marks applied thereon. Each optical fiber tapes includes a plurality of optical fibers intermittently adhered to each other.

Abstract: An optical fiber cable is provided. The cable includes: an optical fiber core having a central axis; a presser winding covering the optical fiber core; a sheath covering the presser winding; two tension members in the sheath and facing each other with the central axis therebetween; and two rip cords facing each other with the central axis therebetween and being in direct contact with the sheath and the presser winding. The optical fiber core includes a plurality of optical fiber tapes arranged around the central axis and having mutually different stripe ring marks applied thereon. Each optical fiber tapes includes a plurality of optical fibers intermittently adhered to each other.

Abstract: [Problem] The thickness on a ripcord in a circular optical cable is reduced, to improve workability. [Solution] An optical cable of the present invention includes: an optical fiber unit including optical fibers; a sheath, having a circular external form, configured to house the optical fiber unit in a housing portion; and two strength members embedded in the sheath; and two rip cords, wherein when a direction of connecting the two strength members sandwiching the housing portion is a first direction and a direction intersecting the first direction is a second direction, in a cross section of the optical cable, a cross-sectional shape of the housing portion has a dimension in the second direction greater than that in the first direction, and the two rip cords is disposed to sandwich the optical fiber unit such that a direction of connecting the two rip cords is in the second direction, in the cross section of the optical cable.

Abstract: An optical fiber cable is provided. The cable includes: an optical fiber core having a central axis; a presser winding covering the optical fiber core; a sheath covering the presser winding; two tension members in the sheath and facing each other with the central axis therebetween; and two rip cords facing each other with the central axis therebetween and being in direct contact with the sheath and the presser winding. The optical fiber core includes a plurality of optical fiber tapes arranged around the central axis and having mutually different stripe ring marks applied thereon. Each optical fiber tapes includes a plurality of optical fibers intermittently adhered to each other.