Abstract: A burring method forms a boss on a metal sheet, using a press die including: a die with a burring hole formed therein; and a burring punch having a shape adapted to be inserted into the burring hole. In the burring method, a width of a clearance formed between the burring hole and the burring punch is in a range not less than 60% and not more than 115%, preferably not less than 65% and not more than 100%, and more preferably, not less than 75% and not more than 95%, of a thickness of the metal sheet, before the metal sheet goes through a burring process.

Abstract: A press die for molding an edge wall at a peripheral edge of a workpiece includes a die convexly formed along a shape of one surface of the edge wall, a punch formed with a concave portion along the other surface of the edge wall, and a stripper for holding the workpiece with the die therebetween, wherein a clearance between the die and the punch is in a range of not less than 70% and not more than 95% of a thickness of the workpiece before forming.

Abstract: A burring method forms a boss on a metal sheet, using a press die including: a die with a burring hole formed therein; and a burring punch having a shape adapted to be inserted into the burring hole. In the burring method, a width of a clearance formed between the burring hole and the burring punch is in a range not less than 60% and not more than 115%, preferably not less than 65% and not more than 100%, and more preferably, not less than 75% and not more than 95%, of a thickness of the metal sheet, before the metal sheet goes through a burring process.

Abstract: The present invention aims to prevent damages of a magnetic tape in a magnetic tape cassette adapted to be operated in a recording and reproducing apparatus which can similarly operate a plurality of magnetic tape cassettes. More specifically, in the invention, differences (A1?B1, A2?B2) between heights A1, A2 of radially inner portions (32a), (42a) of lower flanges (32), (42) and heights B1, B2 of ribs (35a), (45a) of lower halves (35), (45) for restricting a height of the magnetic tape are equal (A1?B1=A2?B2) in a plurality of the magnetic tape cassettes which have the same vertical sizes and different sizes in a horizontal direction.

Abstract: A magnetic tape cassette and a guide roller in which the magnetic tape can stably travel and the magnetic head can read/write the record correctly, and a method of manufacturing the guide roller are provided. The magnetic tape cassette of the present invention comprises a guide roller 106 rotatably supported by the lower cassette half. The guide roller is almost in the shape of a barrel of which a coefficient of curvature T expressed by the expression [1] representing the extent of curvature of the circumferential surface is in the range between 0.001 and 0.01, and comprises a primary molding and injected resin injected within the primary molding for bulging said primary molding into the shape of said barrel shaped cavity that has a largest diameter at the parting line by the injection pressure.

Abstract: In a magnetic tape cassette, a top end portion of a reel urging plate spring for urging a tape reel is subjected to a surface treatment to prevent from a friction. A distance between a couple of flanges of the tape reel is selected to keep a form of the wound magnetic tape, and to prevent the tape running from being disturbed by the increases of a contract resistance of the tape edges to the flanges. Additionally, positioning portions for positioning the magnetic tape cassette relative to a magnetic tape drive device are formed of a differential resin from the resin of the remaining part of the cassette case. Additionally, at least one of both end faces of each guide roller is surface treated so that the end face is not worn through its contact with the cassette half. Further, an information presenting section for displaying variable information is provided at a location other than label areas of the tape cassette.

Abstract: In a magnetic tape cassette, a top end portion of a reel urging plate spring for urging a tape reel is subjected to a surface treatment to prevent from a friction. A distance between a couple of flanges of the tape reel is selected to keep a form of the wound magnetic tape, and to prevent the tape running from being disturbed by the increase of a contact resistance of the tape edges to the flanges. Additionally, positioning portions for positioning the magnetic tape cassette relative to a magnetic tape drive device are formed of a differential resin from the resin of the remaining part of the cassette case. Additionally, at least one of both end faces of each guide roller is surface treated so that the end face is not worn through its contact with the cassette half. Further, an information presenting section for displaying variable information is provided at a location other than label areas of the tape cassette.

Abstract: A magnetic tape cassette and a guide roller in which the magnetic tape can stably travel and the magnetic head can read/write the record correctly, and a method of manufacturing the guide roller are provided. The magnetic tape cassette of the present invention comprises a guide roller (106) rotatably supported by the lower cassette half. The guide roller is almost in the shape of a barrel of which a coefficient of curvature T expressed by the expression [1] representing the extent of curvature of the circumferential surface is in the range between 0.001 and 0.01, and comprises a primary molding and injected resin injected within the primary molding for bulging said primary molding into the shape of said barrel shaped cavity that has a largest diameter at the parting line by the injection pressure.

Abstract: In a magnetic tape cassette, a top end portion of a reel urging plate spring for urging a tape reel is subjected to a surface treatment to prevent from a friction. A distance between a couple of flanges of the tape reel is selected to keep a form of the wound magnetic tape, and to prevent the tape running from being disturbed by the increases of a contract resistance of the tape edges to the flanges. Additionally, positioning portions for positioning the magnetic tape cassette relative to a magnetic tape drive device are formed of a differential resin from the resin of the remaining part of the cassette case. Additionally, at least one of both end faces of each guide roller is surface treated so that the end face is not worn through its contact with the cassette half. Further, an information presenting section for displaying variable information is provided at a location other than label areas of the tape cassette.

Abstract: In a magnetic tape cassette, a top end portion of a reel urging plate spring for urging a tape reel is subjected to a surface treatment to prevent from a friction. A distance between a couple of flanges of the tape reel is selected to keep a form of the wound magnetic tape, and to prevent the tape running from being disturbed by the increase of a contact resistance of the tape edges to the flanges. Additionally, positioning portions for positioning the magnetic tape cassette relative to a magnetic tape drive device are formed of a differential resin from the resin of the remaining part of the cassette case. Additionally, at least one of both end faces of each guide roller is surface treated so that the end face is not worn through its contact with the cassette half. Further, an information presenting section for displaying variable information is provided at a location other than label areas of the tape cassette.

Abstract: In a magnetic tape cassette, a top end portion of a reel urging plate spring for urging a tape reel is subjected to a surface treatment to prevent from a friction. A distance between a couple of flanges of the tape reel is selected to keep a form of the wound magnetic tape, and to prevent the tape running from being disturbed by the increase of a contact resistance of the tape edges to the flanges. Additionally, positioning portions for positioning the magnetic tape cassette relative to a magnetic tape drive device are formed of a differential resin from the resin of the remaining part of the cassette case. Additionally, at least one of both end faces of each guide roller is surface treated so that the end face is not worn through its contact with the cassette half. Further, an information presenting section for displaying variable information is provided at a location other than label areas of the tape cassette.

Abstract: A magnetic tape cassette and a guide roller in which the magnetic tape can stably travel and the magnetic head can read/write the record correctly, and a method of manufacturing the guide roller are provided. The magnetic tape cassette comprises a guide roller (106) rotatably supported by the lower cassette half. The guide roller is almost in the shape of a barrel of which a coefficient of curvature T expressed by the expression [1] representing the extent of curvature of the circumferential surface is in the range between 0.001 and 0.01, and comprises a primary molding and injected resin injected within the primary molding for bulging said primary molding into the shape of said barrel shaped cavity that has a largest diameter at the parting line by the injection pressure.

Abstract: In a magnetic tape cassette, a top end portion of a reel urging plate spring for urging a tape reel is subjected to a surface treatment to prevent from a friction. A distance between a couple of flanges of the tape reel is selected to keep a form of the wound magnetic tape, and to prevent the tape running from being disturbed by the increase of a contact resistance of the tape edges to the flanges. Additionally, positioning portions for positioning the magnetic tape cassette relative to a magnetic tape drive device are formed of a differential resin from the resin of the remaining part of the cassette case. Additionally, at least one of both end faces of each guide roller is surface treated so that the end face is not worn through its contact with the cassette half. Further, an information presenting section for displaying variable information is provided at a location other than label areas of the tape cassette.

Abstract: In a magnetic tape cassette, a top end portion of a reel urging plate spring for urging a tape reel is subjected to a surface treatment to prevent from a friction. A distance between a couple of flanges of the tape reel is selected to keep a form of the wound magnetic tape, and to prevent the tape running from being disturbed by the increase of a contact resistance of the tape edges to the flanges. Additionally, positioning portions for positioning the magnetic tape cassette relative to a magnetic tape drive device are formed of a differential resin from the resin of the remaining part of the cassette case. Additionally, at least one of both end faces of each guide roller is surface treated so that the end face is not worn through its contact with the cassette half. Further, an information presenting section for displaying variable information is provided at a location other than label areas of the tape cassette.

Abstract: A magnetic tape cassette and a guide roller in which the magnetic tape can stably travel and the magnetic head can read/write the record correctly, and a method of manufacturing the guide roller are provided. The magnetic tape cassette of the present invention comprises a guide roller 106 rotatably supported by the lower cassette half. The guide roller is almost in the shape of a barrel of which a coefficient of curvature T expressed by the expression [1] representing the extent of curvature of the circumferential surface is in the range between 0.001 and 0.01, and comprises a primary molding and injected resin injected within the primary molding for bulging said primary molding into the shape of said barrel shaped cavity that has a largest diameter at the parting line by the injection pressure.

Abstract: In a magnetic tape cassette, a top end portion of a reel urging plate spring for urging a tape reel is subjected to a surface treatment to prevent from a friction. A distance between a couple of flanges of the tape reel is selected to keep a form of the wound magnetic tape, and to prevent the tape running from being disturbed by the increase of a contact resistance of the tape edges to the flanges. Additionally, positioning portions for positioning the magnetic tape cassette relative to a magnetic tape drive device are formed of a differential resin from the resin of the remaining part of the cassette case. Additionally, at least one of both end faces of each guide roller is surface treated so that the end face is not worn through its contact with the cassette half. Further, an information presenting section for displaying variable information is provided at a location other than label areas of the tape cassette.

Abstract: A magnetic tape cassette and a guide roller in which the magnetic tape can stably travel and the magnetic head can read/write the record correctly, and a method of manufacturing the guide roller are provided. The magnetic tape cassette of the present invention comprises a guide roller 106 rotatably supported by the lower cassette half. The guide roller is almost in the shape of a barrel of which a coefficient of curvature T expressed by the expression [1] representing the extent of curvature of the circumferential surface is in the range between 0.001 and 0.01, and comprises a primary molding and injected resin injected within the primary molding for bulging said primary molding into the shape of said barrel shaped cavity that has a largest diameter at the parting line by the injection pressure.

Abstract: A method for manufacturing the half body portions of a magnetic tape cassette or the like having an image transfer layer on its outer surface. An image transfer film is placed in a molding cavity, which film includes a base layer, a matting layer, and an image transfer layer. The function of the matting layer is to roughen the surface of the image transfer layer, while allowing easy subsequent peeling therefrom. A molten plastic is injected into the molding cavity against the image transfer layer. After the resulting product solidifies, the product is removed from the molding cavity, and the base layer and matting layer are peeled from the product, leaving the image transfer layer on an outside surface of the product.

Abstract: A method for image-transfer molding half portions of a casing body of a magnetic tape cassette in which no portions of an image transfer film are left in the cassette holes. The image transfer film includes a base layer, a peeling layer, a protective layer, an ink layer, and an adhesive layer. A band of the image transfer film is pinched between dies for molding said half portion, with the adhesive layer positioned so as to abut an outer surface of the molded half portion. A pair of pins is placed in the dies in a position where a hole is to be formed in the half portion, with an end of one of the pins having a peripheral edge portion projecting in a direction parallel to the longitudinal axis of the pin and forming a recess receiving the end of the other of said pins with a portion of the image transfer film sandwiched therebetween.

Abstract: A magnetic tape cassette having an improved tape guide structure and ease of assembly. Tape guides are arranged on both sides of the front opening of the magnetic cassette, the guides being adapted to be brought into sliding contact with the magnetic tape to guide the latter. Each tape guide is in the form of a solid post. Holding members adapted to hold these tape guides are formed on one of upper and lower half cases of the cassette, and tape guides are fixedly inserted into grooves formed in the holding members, with each groove having a portion which is broader than its opening.