Abstract: A photo film cassette has a spool core about which photo film is wound in a form of a roll. A cassette shell contains the spool core in a rotatable manner. Two flanges have a disk shape, and are secured to respective ends of the spool core, for regulating lateral edges of the roll of the photo film. A circumferential lip is disposed on each flange, is extended toward the opposite one of the flanges, wraps one of the lateral edges of an outermost turn of the photo film of the roll, and prevents the photo film from being loosened. A rim portion is disposed on an circular edge of the circumferential lip confronted with the opposite one of the flanges, to project with a bend away from the spool core. A contact face is disposed on the rim portion, and contacts the one of the lateral edges of the photo film when the photo film is unwound from the spool core or wound back about the spool core. The contact face has a contact range of 0.15-0.8 mm in contacting the one of the lateral edges of the photo film.

Abstract: A photo film cassette includes a spool core, on which the photo film is wound in a form of roll. A cassette shell contains the spool core in rotatable fashion. First and second flanges are respectively secured to ends of the spool core, for regulating positions of sides of the photo film roll. A first ring-like lip is formed integrally with a periphery of the first flange, is projected toward the roll, is contacted on one edge of an outermost turn of the roll, and prevent the roll from being loosened. The first and second flanges are formed from resin in accordance with injection molding. The resin has temperature of thermal deformation being 80° C. or higher under 18.6 kg/cm2, modulus in elasticity in flexure being 13,000-30,000 kg/cm2, surface hardness being 80 or more in Rockwell R-scale, and high fluidity in molds for the injection molding. The first and second flanges have an outer diameter of 15 mm or more, thickness of 0.

Abstract: A photo film cassette has a spool core about which photo film is wound in a form of a roll. A cassette shell contains the spool core in a rotatable manner. Two flanges have a disk shape, and are secured to respective ends of the spool core, for regulating lateral edges of the roll of the photo film. A circumferential lip is disposed on each flange, is extended toward the opposite one of the flanges, wraps one of the lateral edges of an outermost turn of the photo film of the roll, and prevents the photo film from being loosened. A rim portion is disposed on an circular edge of the circumferential lip confronted with the opposite one of the flanges, to project with a bend away from the spool core. A contact face is disposed on the rim portion, and contacts the one of the lateral edges of the photo film when the photo film is unwound from the spool core or wound back about the spool core. The contact face has a contact range of 0.15.0.8 mm in contacting the one of the lateral edges of the photo film.

Abstract: A photo film cassette includes a spool core, on which the photo film is wound in a form of roll. A cassette shell contains the spool core in rotatable fashion. First and second flanges are respectively secured to ends of the spool core, for regulating positions of sides of the photo film roll. A first ring-like lip is formed integrally with a periphery of the first flange, is projected toward the roll, is contacted on one edge of an outermost turn of the roll, and prevent the roll from being loosened. The first and second flanges are formed from resin in accordance with injection molding. The resin has temperature of thermal deformation being 80.degree. C. or higher under 18.6 kg/cm.sup.2, modulus in elasticity in flexure being 13,000-30,000 kg/cm.sup.2, surface hardness being 80 or more in Rockwell R-scale, and high fluidity in molds for the injection molding. The first and second flanges have an outer diameter of 15 mm or more, thickness of 0.3 mm or less, and a maximum projected area of 100 mm.sup.

Abstract: A cartridge including a cartridge case having a disc-shaped recording medium received therein so as to allow predetermined information signals to be recorded and reproduced, and a shutter and method for producing the shutter which is molded of a synthetic resin to slidably open and close an opening portion formed on the cartridge case so as to allow at least a part of the disc-shaped recording medium to be exposed to the outside. The shutter includes an upper main plate, a lower main plate and a coupling plate which connects the upper main plate to the lower main plate via the coupling plate in an integrally molded state while having a U-shaped cross-sectional contour to hold the cartridge case in a clamped state. A gate used for performing a molding operation is formed on the outer surface of the side plate, with the position of the gate being determined such that it always remains within an effective opening region corresponding to the opening portion.

Abstract: In a method for injection molding a plastic shutter for a magnetic disk cartridge, the shutter having windows corresponding to an opening formed in a magnetic disk cartridge and being substantially U-shaped in section, the diameter of an injection cylinder for injecting molten resin for forming the shutter is determined according to the following equation:D.sup.2 =A.times.C.times.M / .pi.where D is the diameter (mm) of the injection cylinder, C is the number of the plastic shutters molded simultaneously with one metal mold, M is the volume (cm.sup.3) of the plastic shutter, and A is the cylinder coefficient of the injection cylinder and is limited as follows:130.ltoreq.A.ltoreq.510.The inventive method is considerably stable, being free from the difficulties that short shot occurs with the metal mold, and the resultant shutter is deformed near the gate of the metal mold, or bent in its entirety.

Abstract: A cartridge including a cartridge case having a disc-shaped recording medium received therein so as to allow predetermined information signals to be recorded and reproduced, and a shutter molded of a synthetic resin to slidably open and close an opening portion formed on the cartridge case so as to allow at least a part of the disc-shaped recording medium to be exposed to the outside. In accordance with the present invention, the shutter is composed of an upper main plate, a lower main plate and a coupling plate which connects the upper main plate to the lower main plate via the coupling plate in an integrally molded state while having an U-shaped cross-sectional contour to hold the cartridge case in a clamped state. A gate used for performing a molding operation is formed on the outer surface of the side plate, with the position of the gate being determined such that it always remains within an effective opening region corresponding to the opening portion.

Abstract: A method for removing dirt from a web in which a blow-off nozzle is provided extending over the width of a web. An edge of the nozzle at an end thereof is positioned close to one surface of the web. Air is blown through the nozzle while said web is being run past said nozzle so that deposits are removed from a surface of the web with the edge while the web is maintained in a floating state separated from the nozzle.

Abstract: An application device capable of very rapidly applying a liquid in the form of a thin film to a continuously moving flexible carrier in such a manner as to avoid corrosion and wear to the surface of the doctor edge portion of the application device to thus avoid the formation of streaks on the surface of the applied liquid. A clearance between the surface of the carrier and the surface of the doctor edge portion is made larger at the downstream end of the surface of the doctor edge portion than at the upstream part thereof. For this purpose, a support roller is provided near the downstream end of the surface of the doctor edge portion so that the clearance between the surface of the doctor edge portion and the surface of the carrier can be appropriately controlled along substantially the entire width of the doctor edge portion by adjustably displacing the roller.

Abstract: A magnetic recording comprising a non-magnetic support having thereon first and second magnetic layers containing a binder and a ferromagnetic powder. In a first embodiment, the content of the binder in each magnetic layer containing a vinyl chloride resin or a cellulose resin is characterized in relation to the quantity of the ferromagnetic powder contained therein. In a second embodiment, each of the magnetic layers is characterized in terms of a difference in glass transition point of a polyurethane resin contained therein. In a third embodiment, each of the magnetic layers is characterized in terms of thickness and polyisocyanate content, wherein the content of the polyisocyanate in the first magnetic layer is at least one part by weight larger than the amount of the polyisocyanate in the second magnetic layer.

Abstract: A novel magnetic recording medium is disclosed which comprises a non-magnetic support having thereon at least three magnetic layers each layer of which containing a ferromagnetic powder dispersed in a binder, wherein the outermost magnetic layer arranged farthest from the support has a dry thickness of 1 .mu.m or less, and the at least three magnetic layers each exhibit coercive force Hc (Oe) satisfying the following relationships: ##EQU1## wherein H.sub.1 represents Hc of the outermost magnetic layer; Hn represents Hc of the magnetic layer which is the n-th layer from the outermost magnetic layer and arranged between the outermost layer and the non-magnetic support; and Dn represents the distance (.mu.m) from the top surface of the outermost magnetic layer to the top surface of the n-th layer. A novel process for the preparation of the magnetic recording medium is also disclosed.

Abstract: An application device for applying a liquid such as a magnetic coating liquid to the surface of a continuously moving web in which the amount of chipping of the surface portions of the outlet portion of the coating head thereof, and hence the amount of streaking in the applied layer of liquid, are remarkably reduced. The outlet portion of the application head is made of a very hard alloy, preferably tungsten carbide, containing crystal grains of a carbide 5 .mu.m or less in mean diameter conjoined to each other by a metal, preferably cobalt in an amount of 12% or less.

Abstract: A method for manufacturing a magnetic recording medium in which shavings are not generated when an easily bent thin web comes into contact with contact members of a coating head, a conveying system, rolls in calendaring treatment, etc., in which, during coating, a coating having an even coating thickness and good surface properties is formed, and in which a coating liquid does not spread in such a manner as to cause defects such as coating unevenness and the like. In accordance with the inventive method, to manufacture a magnetic recording medium in which a coating liquid is applied onto a surface of a continuously running flexible support except widthwise edge portions of the support while a slot top end of a coating head is pressed against the surface of the flexible support, a material selected from a polymer film, a carbon dispersing liquid, a fatty-acid lubricant, and a fluorine-group lubricant is applied onto at least portions of the flexible support corresponding to the edge portions.

Abstract: A coating material and apparatus in which the edge portions of the web being coated are supported off the edge portions of the coating head. In one embodiment, recesses are formed in the edge portions of the coating head, while in another embodiment a fluid is jetted towards the edge portions of the web. With the invention, scratching and the like of the edge portions of the web are eliminated, and the web is coating to a uniform thickness in the width direction thereof.

Abstract: A method for manufacturing a magnetic recording medium or the like and an applicator device for applying a coating to manufacture a magnetic recording medium resulting in the production of a recording medium having a uniform coating of magnetic liquid without streaking. In one embodiment, the flow index A expressed by an equation (1) below and in which L, V and .gamma.

Abstract: A method for manufacturing a magnetic recording medium or the like and an applicator device for applying a coating to manufacture a magnetic recording medium resulting in the production of a recording medium having a uniform coating of magnetic liquid without streaking. In one embodiment, the flow index A expressed by an equation (1) below and in which L, V and .gamma.

Abstract: A magnetic recording medium for a video tape recorder is disclosed, comprising a nonmagnetic support having thereon in the following order an under magnetic layer containing ferromagnetic particles of metal oxide and an upper magnetic layer containing ferromagnetic particles of metal oxide, wherein said under magnetic layer contains the ferromagnetic particles having a specific surface area by a BET method of from 26 to 50 m.sup.2 /g and a coercive force (Hc.sub.1) of from 500 to 1,000 Oe; said upper magnetic layer contains the ferromagnetic particles having a specific surface area by a BET method of from 30 to 60 m.sup.2 /g and a coercive force (Hc.sub.2) of from 600 to 1,200 Oe; the dry thickness of the upper magnetic layer is from 0.1 to 1.0 .mu.m; and the coercive force (Hc.sub.2) of the ferromagnetic particles for the upper magnetic layer is higher than the coercive force (Hc.sub.1) of the ferromagnetic particles for the under magnetic layer.

Abstract: A coating method and an extrusion-type coating head in which turbulence at the junction between two flows of coating materials is prevented to provide multi-layer simultaneous coating over a wide range of coating rates and with a good coating quality. An intermediate block is sandwiched betwen a rear block defining a back edge and a front block defining a doctor edge. Two coating flows pass through slits formed on either side of the intermediate block, joining at the top end of the intermediate block and flowing together into a short slot extending between the end of the intermediate block and the outlet of the head.

Abstract: A multi-layer coating method by which multi-layered magnetic recording media having good recording characteristics can be produced consistently at high speed with multiple thin layers being coated simultaneously while insuring effective prevention of unwanted phenomena such as color unevenness and longitudinal streaks. A plurality of organic solvent based dispersions that are non-Newtonian fluids having fine particles dispersed therein are simultaneously applied in superposition onto a continuously running nonmagnetic support using an extrusion type applicator head. The coating operation is performed in such a manner that the Reynolds number as determined by the average of the kinetic viscosity coefficients of the dispersions, the coating speed and the equivalent diameter during coating is adjusted to 400 or below, and that, at the same time, the yield stress of at least the dispersion for the topmost layer is adjusted to 10 dyne/cm.sup.2 or more.

Abstract: A coating method and an extrusion-type coating head in which turbulence at the junction between two flows of coating materials is prevented to provide multi-layer simultaneous coating over a wide range of coating rates and with a good coating quality. An intermediate block is sandwiched between a rear block defining a back edge and a front block defining a doctor edge. Two coating flows pass through slits formed on either side of the intermediate block, joining at the top end of the intermediate block and flowing together into a short slot extending between the end of the intermediate block and the outlet of the head.