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 method and apparatus for removing particles from a flexible sheet. The sheet is run over a rotating rod, rotating oppositely to the moment of the sheet. The rod is immersed on its lower side in a bath of solvent and excess solvent is removed from the bath and is filtered. Additionally, solvent may be applied to the sheet before it reaches the rotating rod or a negative pressure applied just upstream of the rod sucks away the particles.

Abstract: A method and apparatus for removing particles from a flexible sheet. The sheet is run over a rotating rod, rotating oppositely to the moment of the sheet. The rod is immersed on its lower side in a bath of solvent and excess solvent is removed from the bath and is filtered. Additionally, solvent may be applied to the sheet before it reaches the rotating rod or a negative pressure applied just upstream of the rod sucks away the particles.

Abstract: A method of producing a magnetic recording medium comprises forming a magnetic layer by applying a magnetic film forming liquid onto a continuously running non-magnetic support, applying a magnetic field onto the magnetic film forming liquid before the magnetic film forming liquid has dried, and then drying the magnetic film forming liquid. A non-magnetic undercoating layer is formed on the support simultaneously with the step of forming the magnetic layer by simultaneously applying to the support a non-magnetic undercoating forming liquid and the magnetic film forming liquid. The magnetic field is applied before both the magnetic film forming liquid and non-magnetic undercoating forming liquid have dried.

Abstract: A magnetic tape winding method and apparatus in which a magnetic field is applied to a magnetic tape during winding on a reel to even up the edges of the wound tape. After winding, the magnetic tape is demagnetized.

Abstract: A method of fabricating a magnetic tape in which a non-magnetic support is simultaneously coated with two coating solutions, with the upper layer having a dried thickness no thicker than that of the lower layer. While the layers remain wet, the layers are subjected to magnetic orientation and are then dried.

Abstract: A method of making a magnetic recording medium by forming a recording layer composed of a ferromagnetic material on a strip-like substrate comprises a first step of applying the ferromagnetic material onto the surface of the substrate, a second step of drying the ferromagnetic material applied on the surface of the substrate, a third step of grinding the surface of the dried recording layer on the substrate, a fourth step of removing process grains clinging to the ground surface of the recording layer, and a fifth step of calendering the surface of the recording layer from which the process grains have been removed.

Abstract: A magnetic tape winder in which a magnetic tape is wound onto a flanged reel which being subjected to a magnetic field in the width direction of the tape. The reel is fit between the poles of a U-shaped magnet.

Abstract: A method of applying a liquid to a moving web while pushing an extrusion application head to the moving web without supporting the moving web on the reverse side thereof. The application is performed while the accumulation of the liquid to be applied to the moving web is maintained by (a) the moving web and (b) an edge of the back blade of the extrusion application head, the edge being defined by the intersection of (1) a first surface of the back blade which faces the front blade and which is nearest the web, and (2) a second surface of the back blade which is more remote from the front blade than the first surface and, wherein the pressure of the liquid of the accumulation located between the web and the outlet portion of the slit of the extrusion application head is set within a range from 0.2 kg/cm.sup.2 gauge to 0.8 kg/cm.sup.2 gauge per 50 cm of width of applied liquid.

Abstract: In a magnetic tape winding system for winding a magnetic tape by a predetermined length around a small winding frame from a magnetic tape feed roll, the condition of winding of the magnetic tape around the small winding frame is detected, and the winding surface condition of the magnetic tape wound around the small winding frame is optically imaged at predetermined timing. The quality of the winding surface condition of the magnetic tape wound around the small winding frame is judged by a calculation processing of image signals obtained by the optical imaging. The speed of magnetic tape winding around the small winding frame is adjusted based on results of the judgment.

Abstract: The perpendicular magnetic orientation of a magnetic layer containing platelet-form ferromagnetic particles coated on a web support is effectively performed by passing a web having thereon the coated magnetic layer in an undried state through a magnetic field formed by plural pairs of opposite pole type magnets disposed in the travelling direction of the web with a gap between adjacent pairs of magnets, while supplying drying air through each gap onto the surface of the travelling web to substantially complete the drying of the coated layer while the web is in the magnetic field. A partition may be inserted in each gap so that the lower end of the partition is close to the upper surface of the travelling web to divide the gap into a front section and a back section, and the drying air may be passed through these sections.

Abstract: A method for drying a running web or belt-like support with an organic solvent-containing coating solution coated thereon is described, comprising introducing the support into a drying room and drying it mainly by hot air blown into the drying room in parallel to the running direction of the support in such a manner that it does not strike directly on the coated surface of the support, while conveying the support in an arch-like or straight form on rolls provided in the drying room. This drying method provides high quality coated-layers and increases producitivity. Further, this method is particularly useful in the preparation of magnetic recording material.

Abstract: A method of winding a predetermined length of magnetic recording tape from a large reel (on which the tape is initially wound), onto a small reel, in which the running speed of the tape is gradually increased at the beginning stage of each winding cycle to a predetermined high speed, is subsequently kept at the high speed, and is gradually slowed down near the end of the cycle, and then the tape is finally stopped to end the cycle. Simultaneously with the beginning of each winding cycle, an encoder begins to generate a pulse train, the number of pulses of which is in proportion to the number of rotations of the small reel. The number of pulses in the pulse train is counted and the tape running speed is gradually slowed down when the number of pulses counted reaches a predetermined value according to the time at which the tape running speed is to be gradually slowed down.

Abstract: A coating method and coating extruder in which color non-uniformity and stripes in a coated solution on a surface of a continuously-run flexible belt-shaped support are eliminated. Coating solution is supplied from a solution pool of the extruder through a slit at a rate which is greater than that which the coating solution is applied to the support through the slit. A portion of the coating solution is discharged from the solution pool from a position furthers, in the widthwise direction of the support, from the solution supplying point of the solution pool.

Abstract: An extrusion type coating apparatus for applying a coating film to a support has a bent doctor edge made of cemented carbide having a very large hardness. The bent doctor edge has a very large obtuse angle and the resulting doctor edge allows the coating film to be applied smoothly to the support. Since the doctor edge is made of cemented carbide having a very high hardness, the doctor edge is not unduly worn by abrasives contained in the coating film thereby improving the wear-resistance of the apparatus.

Abstract: A coating method and coating extruder in which color non-uniformity and stripes in a coated solution on a surface of a continuously-run flexible belt-shaped support are eliminated. Coating solution is supplied from a solution pool of the extruder through a slit at a rate which is greater than that which the coating solution is applied to the support through the slit. A portion of the coating solution is discharged from the solution pool from a position furthers, in the widthwise direction of the support, from the solution supplying point of the solution pool.

Abstract: Method and apparatus for coating a web with a magnetic coating liquid in which the coating is applied exceedingly uniformly. The web to be coated is continuously transported past a nozzle in an extrusion-type coating unit with the magnetic coating liquid discharged through the nozzle and wherein:(a) V.sub.0 >0.3 m/sec,(b) 3 m/sec>V.sub.1 >0.1 m/sec,(c) 3>V.sub.1 /V.sub.0, and(d) 15 cm>d>0.2 cmwhere V.sub.0 is the coating liquid discharge speed at the nozzle of the extrusion-type coating unit, V.sub.1 is the coating liquid striking speed at the surface of the web, and d is the distance between the nozzle and the surface of the web.