JP5730166B2 - Application sheet holding method for application surface observation - Google Patents

Description

  The present invention relates to a method for fixing an application sheet in order to observe an application surface of a flexible application sheet.

  When a coating sheet is produced by forming a coating layer on the surface of a flexible sheet made of resin or the like, the surface of the coating layer (that is, the coating surface) is often observed for the purpose of quality control or the like.

  For example, in the field of magnetic recording media, so-called coating film defects such as protrusions, paint dropouts, and dents present on the surface of a magnetic layer that is a coating layer, dropout, reproduction output, or S / N during recording or reproduction. The function as a recording medium is greatly impaired. Therefore, it is important to detect coating defects on the surface of the magnetic layer as early as possible in the manufacturing process of the magnetic recording medium and take appropriate measures.

  In order to discover coating film defects, it is necessary to observe the surface of the magnetic layer. In general, in the manufacture of magnetic recording tape, the surface of the magnetic layer at the stage of a wide sheet coated with a magnetic layer (generally called “raw fabric”) before being cut into a tape shape that is the final product form. It is desirable to observe This is because it is possible to reduce waste of materials and time by appropriately dealing with the type and degree of coating film defects in the original fabric.

  Patent Document 1 describes a method of detecting a defect in a magnetic layer by irradiating the magnetic layer surface of the magnetic tape with light while the magnetic tape is running on a guide plate.

Japanese Patent Laid-Open No. 9-127010

  The defect detection method of Patent Document 1 is for a magnetic tape obtained by cutting an original fabric into a tape shape. If this method is applied to the original fabric before cutting, the original fabric has a much larger width than that of magnetic tape, so it is difficult to run the original fabric without wrinkles or sagging and with high accuracy. It is difficult to detect defects on the surface of the magnetic layer.

  Therefore, it is conceivable to place the original fabric on a flat plate having a width equivalent to that of the original fabric and observe the surface of the magnetic layer in a stationary state, instead of running the original fabric.

  However, if the original fabric is simply placed on the flat plate, the air between the original fabric and the flat plate cannot be completely discharged, and it is difficult to keep the original fabric in a flat state. If the original flat state is poor, the surface of the original magnetic layer cannot be observed accurately.

  On the other hand, if the flat plate is made of, for example, a porous body having open cells, and the raw material is sucked into the surface of the porous material, the air between the raw material and the flat plate can be discharged. However, since the unevenness caused by the unevenness of the surface of the porous body is reflected on the surface of the original fabric, the surface of the magnetic layer of the original fabric cannot be observed with high accuracy. This problem can be reduced by reducing the size of the open cells in the porous body, but the open cells are likely to be clogged, so it is necessary to observe in a clean atmosphere such as a clean room of class 100 or less, and magnetic recording. Not suitable for normal production environment of media.

  In recent years, the demand for higher density and higher capacity for magnetic tape cassettes has increased, and as a result, the level of demand for defects on the surface of the magnetic layer has increased, and the total thickness of magnetic tape is becoming thinner. In order to detect finer defects accurately in a short time, it is necessary to keep the original flat. However, maintaining the original flat with no wrinkles or sagging reduces the total thickness of the original. The more difficult it is.

  An object of the present invention is to solve the above-described conventional problems and to facilitate surface observation of the coated surface by holding the coated sheet in a substantially flat shape without wrinkles or tarnish.

  The present invention relates to a method of holding the coating sheet on a base surface of a fixed base in order to observe the coating surface of the coating sheet. The fixed base protrudes from the base surface and extends along the first direction, and is formed on both sides of the ridge having a smooth upper surface and the second direction perpendicular to the first direction with respect to the ridge. A first suction hole. The coating sheet is placed on the base surface so that the coating surface faces away from the base surface and covers the ridges and the first suction holes, and the coating sheet is placed on the first suction holes. To apply the coating sheet to the top surface of the ridge.

  According to the present invention, a tension is applied to the application sheet by sucking the application sheet through the first suction hole, and the application sheet is brought into close contact with the upper surface of the ridge by this tension. Therefore, even if the coating sheet is thin and has no stiffness, the coating sheet can be held substantially flat on the smooth upper surface of the ridges without wrinkles or tarnish. Therefore, it is possible to accurately observe the coated surface in a short time.

FIG. 1 is a diagram showing a schematic configuration of an apparatus for carrying out a method for holding a coated sheet according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the fixing base according to the first embodiment of the present invention. FIG. 3 is a plan view of the fixed base according to the first embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of the protrusions of the fixing base according to the first embodiment of the present invention along the plane including line 4-4 in FIG. FIG. 5 is an enlarged cross-sectional view showing a state in which the magnetic sheet is attracted to the first suction hole and the second suction hole in the first embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of the protrusions of the fixing base according to the second embodiment of the present invention. FIG. 7 is a plan view of a fixing base according to Embodiment 3 of the present invention. FIG. 8 is an enlarged cross-sectional view of the protrusions of the fixing base according to the third embodiment of the present invention along the plane including line 8-8 in FIG. FIG. 9 is an enlarged cross-sectional view illustrating a state in which the magnetic sheet is attracted to the first suction hole and the second suction hole in the third embodiment of the present invention.

  In the above-described method for holding a coated sheet of the present invention, it is preferable that the ridge is provided with inclined surfaces adjacent to the upper surface on both sides in the second direction with respect to the upper surface. This preferable configuration is advantageous for holding the coated sheet substantially flat on the upper surface of the ridge without wrinkles or tarnish.

  It is preferable that the said protruding item | line is provided with the perpendicular | vertical surface substantially perpendicular | vertical with respect to the said base surface adjacent to the said inclined surface. According to such a preferable configuration, since a larger tension can be generated in the application sheet, it is further advantageous to hold the application sheet in a substantially flat shape on the upper surface of the ridge without wrinkles or tarnish.

  It is preferable that the first suction hole is in contact with the lower end of the ridge. According to such a preferable configuration, since a larger tension can be generated in the application sheet, it is further advantageous to hold the application sheet in a substantially flat shape on the upper surface of the ridge without wrinkles or tarnish.

  It is preferable that the groove | channel extended along the said 1st direction is formed in the said base surface adjacent to the said protruding item | line. In this case, it is preferable that the first suction hole is formed on the bottom surface of the groove. According to such a preferable configuration, since a larger tension can be generated in the application sheet, it is further advantageous to hold the application sheet in a substantially flat shape on the upper surface of the ridge without wrinkles or tarnish.

  The first suction hole preferably has a circular shape with a diameter of 2.5 mm or less or a slot shape with a width of 1 mm or less. According to such a preferable configuration, an appropriate tension can be applied without causing wrinkles on the coated sheet.

  It is preferable that a second suction hole is formed at a position farther from the ridge than the first suction hole. In this case, it is preferable that the coating sheet is sucked into the second suction hole. According to such a preferable configuration, the application sheet is displaced with respect to the first suction hole or separated from the first suction hole by vibration when the fixing base is moved while the first suction hole sucks the application sheet. Can be prevented.

  It is preferable that the groove | channel extended along the said 1st direction is formed in the said base surface adjacent to the said protruding item | line. In this case, the second suction hole is preferably formed on the bottom surface of the groove. According to such a preferable configuration, since a larger tension can be generated in the application sheet, it is further advantageous to hold the application sheet in a substantially flat shape on the upper surface of the ridge without wrinkles or tarnish.

  The second suction hole preferably has a circular shape with a diameter of 2.5 mm or less or a slot shape with a width of 1 mm or less. According to such a preferable configuration, the application sheet can be held on the fixed base without causing wrinkles on the application sheet.

  It is preferable that the surface roughness of the upper surface of the ridge satisfies Ra ≦ 0.05 μm and Rmax ≦ 0.2 μm. According to such a preferable configuration, the unevenness of the upper surface of the ridge is less likely to appear on the application surface of the application sheet in close contact with the upper surface of the ridge, which is advantageous for accurately observing the application surface in a short time. .

  It is preferable that the total thickness of the coating sheet is 20 μm or less. When the present invention is applied to such a thin and firm application sheet, the effects of the present invention are remarkably exhibited.

  The coated sheet is preferably a magnetic recording medium sheet. According to such a preferable configuration, the surface of the coating type magnetic layer can be observed in a short time and the surface defects can be accurately grasped. Therefore, it is advantageous for quality control in the manufacture of the raw material of the magnetic recording tape.

  Below, this invention is demonstrated in detail, showing suitable embodiment. However, it goes without saying that the present invention is not limited to the following embodiments. For convenience of explanation, the drawings referred to in the following description show only the main members necessary for explaining the present invention in a simplified manner among the constituent members of the embodiment of the present invention. Therefore, the present invention can include arbitrary components not shown in the following drawings. In addition, the dimensions of the members in the following drawings do not faithfully represent the actual dimensions of the constituent members and the dimensional ratios of the members.

(Embodiment 1)
FIG. 1 is a diagram showing a schematic configuration of an apparatus for carrying out a method for holding a coated sheet according to Embodiment 1 of the present invention. A flat plate-like fixing table 20 is placed on the holding table 11. Three ridges 30 protrude from an upper surface (hereinafter referred to as “base surface”) 21 of the fixed base 20. The three ridges 30 are arranged in parallel to each other and at a predetermined interval. For convenience of the following description, an XYZ orthogonal coordinate system is set in which an axis parallel to the normal of the base surface 21 is the Z axis, and two axes orthogonal to the Z axis are the X axis and the Y axis. The Y axis is parallel to the direction (first direction) in which the ridges 30 extend. The base surface 21 is parallel to the horizontal plane.

  The holding table 11 on which the fixed table 20 is placed is mounted on an XY drive mechanism (not shown). Thereby, the fixed base 20 can move in the X-axis direction and the Y-axis direction.

  A vacuum pump 41 is connected to the fixed base 20 via a tube 42.

  A camera 45 for photographing a coating sheet (not shown) held on the base surface 21 (particularly the ridges 30) is installed above the fixed base 20. The video signal photographed by the camera 45 is output to the computer 46, subjected to predetermined image processing and the like, and the result is displayed on the display 47.

  2 is a perspective view of the fixed base 20, FIG. 3 is a plan view of the fixed base 20, and FIG. 4 is an enlarged cross-sectional view of the ridge 30 along the plane including line 4-4 of FIG.

  The fixed base 20 is made of, for example, stainless steel, and its upper surface (base surface) 21 is processed into a flat surface. A ridge 30 projects upward from the base surface 21. As shown in FIG. 4, the ridge 30 includes a smooth upper surface 31, inclined surfaces 32 connected to both ends of the upper surface 31 in the X-axis direction, and a vertical surface 33 connected to the lower end of the inclined surface 32. With. The upper surface 31 is a flat surface parallel to the XY plane (a plane parallel to the X axis and the Y axis). The inclined surface 32 is inclined at an angle θ with respect to the XY plane (that is, the upper surface 31). The vertical plane 33 is substantially parallel to the YZ plane (a plane parallel to the Y axis and the Z axis). The lower end of the vertical surface 33 is connected to the base surface 21.

  On the base surface 21, first suction holes 26 are formed on both sides of the ridge 30 in the X-axis direction, and the first suction holes 26 are on the opposite side of the first suction hole 26 from the ridge 30. A second suction hole 27 is formed slightly apart from the second suction hole 27. As shown in FIGS. 2 and 3, the first suction holes 26 and the second suction holes 27 are arranged on both sides of each protrusion 30 at a constant pitch in the Y-axis direction. As shown in FIG. 4, all the first suction holes 26 and the second suction holes 27 formed in the fixed base 20 are mutually connected via air passages 29 a and 29 b formed in the fixed base 20. It is communicated. The air passages 29a and 29b are connected to a vacuum pump 41 (see FIG. 1) via a tube.

  Hereinafter, an example of observing the surface of a magnetic layer coated and formed on an original sheet (that is, a magnetic recording medium sheet, hereinafter referred to as “magnetic sheet”) for producing a coated magnetic recording tape as a coated sheet will be described. Next, the observation method of the coated surface of the first embodiment will be described.

  In the manufacture of a magnetic recording tape, a long magnetic sheet is generally wound into a roll. A roll of magnetic sheet is called a “raw roll”. The magnetic sheet is unwound from the original roll by a predetermined length and cut, and placed on the fixed base 20 with the magnetic layer facing upward. At this time, the magnetic sheet is placed so that the longitudinal direction thereof is parallel to the X-axis direction. The magnetic sheet covers the three ridges 30 and all the first suction holes 26 and the second suction holes 27.

  Next, the vacuum pump 41 is driven. The inside of the first suction hole 26 and the second suction hole 27 is depressurized, and the air interposed between the base surface 21 and the magnetic sheet is discharged through the first suction hole 26 and the second suction hole 27, and further the magnetic The sheet is sucked into the first suction hole 26 and the second suction hole 27. Therefore, as shown in FIG. 5, the magnetic sheet 1 is sucked into the first suction holes 26 and the second suction holes 27 arranged on both sides of the ridges 30, so that the portion covering the ridges 30 of the magnetic sheet 1 is The tension in the X-axis direction is applied and stretched. As a result, the magnetic sheet 1 is brought into close contact with the upper surface 31 of the ridge 30 and is stretched in a planar shape along the smooth upper surface 31 without causing wrinkles or tarnish.

  In this state, the magnetic layer surface of the magnetic sheet positioned on the upper surface 31 of the ridge 30 is visually observed and photographed by the camera 45 to perform predetermined image processing and analysis. The surface of the magnetic layer on the three ridges 30 can be scanned with the camera 45 by moving the fixed base 20 in the X axis direction and the Y axis direction by the XY drive mechanism. The type, number, degree (for example, size), etc. of defects are evaluated by visual inspection and / or image processing by the computer 46. When the defect exceeds a preset standard from the viewpoint of dropout, S / N, etc., appropriate measures described later are taken for quality control.

  As described above, according to the first embodiment, a wide magnetic sheet can be held in a substantially planar shape on the smooth upper surface 31 of the ridge 30 without causing wrinkles or sagging. Therefore, it is possible to accurately observe the surface of the magnetic layer in a short time.

  In the first embodiment, the surface can be observed only in a portion of the magnetic sheet disposed on the upper surface 31 of the ridge 30. When it is necessary to observe the surface of other portions, the surface observation may be repeated by moving the magnetic sheet in the X-axis direction with respect to the fixed base 20.

  In general, it is desired to perform a quality confirmation inspection for each raw roll. The length of a magnetic sheet wound around one original roll is often 500 m or more. Therefore, the observation of the surface of the magnetic layer is usually performed by cutting out, for example, about 1 m of the magnetic sheet of the surface layer portion and the deep layer portion of the original fabric roll. The width of the magnetic sheet is usually about 330 mm to 1000 mm. The above example assumes a case where the width of the magnetic sheet is 500 mm (hereinafter, this example is referred to as “example”). In this embodiment, the width (X-axis direction dimension) of the upper surface 31 of the ridge 30 is 28 mm, and the distance between the vertical surfaces 33 on both sides of the ridge 30 (that is, the width of the ridge 30) is 30 mm. The length (Y-axis direction dimension) of the upper surface 31 of the ridge 30 is 280 mm. In the present embodiment, such ridges 30 are arranged in three rows at equal intervals in the width direction of the magnetic sheet.

  The above-described dimensions of each part of the ridge 30 and the number of ridges 30 can be appropriately changed according to the width and length of the magnetic sheet to be inspected.

  In general, it is desirable that the width of the upper surface 31 of the ridge 30 is wide from the viewpoint of expanding the observation target region. However, as the width of the upper surface 31 increases, the contact area between the upper surface 31 and the magnetic sheet increases, so that the tension generated by attracting the magnetic sheet 1 to the first suction hole 26 can be understood from FIG. Since the magnetic sheet 1 is hardly applied to the entire upper surface 31, the adhesion of the magnetic sheet 1 to the upper surface 31 is lowered. Therefore, the width of the upper surface 31 is generally preferably 30 mm or less.

  In general, it is also desirable that the length of the upper surface 31 of the ridge 30 is long from the viewpoint of expanding the observation target region. Moreover, if the upper surface 31 becomes long, the sampling number of a magnetic sheet can be decreased. However, when the upper surface 31 becomes longer, a longer magnetic sheet must be placed on the fixed base 20 accordingly. When the magnetic sheet becomes longer and therefore its area becomes larger, the magnetic sheet is wrinkled or creased in the process until the magnetic sheet is cut out from the raw roll and placed on the fixed base 20, Defects are generated in the magnetic layer. Therefore, the possibility of detecting a defect other than a defect on the surface of the magnetic layer that should be detected in the manufacturing process is increased, and the inspection accuracy is lowered. Therefore, the size of the magnetic sheet placed on the fixed base 20 should be less than that which can be handled by an operator without causing wrinkles or creases. From such a point of view, there is an upper limit on the length of the upper surface 31, and it is generally preferably 500 mm or less, although it varies depending on the mechanical strength (or total thickness) of the magnetic sheet.

  The number of ridges 30 can be arbitrarily set in consideration of the width of the magnetic sheet to be inspected. When the three ridges 30 are arranged at equal intervals in the width direction of the magnetic sheet as in the above-described embodiment, a total of three places, that is, a central portion in the width direction of the magnetic sheet and portions near both ends can be observed. Therefore, since more information can be obtained by one scan in the X-axis direction, an efficient inspection can be performed. Of course, the number of ridges 30 may be two or less, or may be four or more.

  As described above, the magnetic sheet adheres to the upper surface 31 of the ridge 30. Therefore, it is desirable that the surface of the upper surface 31 be as smooth as possible so that the irregularities on the surface of the upper surface 31 do not affect the surface of the magnetic layer of the magnetic sheet. Specifically, the surface roughness of the upper surface preferably satisfies Ra ≦ 0.05 μm, more preferably Ra ≦ 0.025 μm, and further satisfies Rmax ≦ 0.2 μm and further Rmax ≦ 0.1 μm. It is preferable.

  In the above embodiment, the upper surface 31 is a flat surface, but the shape of the upper surface 31 is not limited to this, and may be, for example, a cylindrical surface having the Y-axis direction as the central axis direction. However, from the viewpoint of capturing a clear image with the camera 45, it is preferable that the magnetic layer surface of the magnetic sheet does not deviate from the focal depth of the camera 45.

  The inclination angle θ (see FIG. 4) of the inclined surface 32 with respect to the horizontal plane is not particularly limited. However, if the inclination angle θ is too small, the tension generated in the magnetic sheet 1 by the first suction holes 26 attracting the magnetic sheet 1 becomes difficult to be transmitted to the portion on the upper surface 31 of the magnetic sheet 1. May be difficult to adhere to the upper surface 31. On the contrary, if the inclination angle θ is too large, when the vacuum pump 41 is driven after the magnetic sheet 1 is placed on the fixed base 20, the tension becomes magnetic at the moment when the magnetic sheet 1 is attracted to the first suction hole 26. The magnetic sheet 1 is easily transmitted to the portion on the upper surface 31 of the sheet 1 and wrinkles are easily generated on the upper surface 31. Therefore, it is preferable that the inclination angle θ is generally not less than 30 degrees and not more than 80 degrees. In the above embodiment, the angle was 45 degrees. The inclined surface 32 may be omitted depending on conditions such as the physical properties of the magnetic sheet and the attractive force of the first suction hole 26, and the vertical surfaces 33 may be connected to both ends of the upper surface 31.

  The boundary between the upper surface 31 and the inclined surface 32 and / or the boundary between the inclined surface 32 and the vertical surface 33 may be subjected to a known chamfering process having a curved surface shape or a planar shape. When the chamfering process is performed, the tension applied to the portion on the upper surface 31 of the magnetic sheet 1 may change as the first suction hole 26 attracts the magnetic sheet 1 in some cases.

  Next, the first suction hole 26 and the second suction hole 27 will be described (see FIGS. 4 and 5).

  The main function of the first suction hole 26 is to attract the magnetic sheet 1, generate tension on the magnetic sheet 1, and bring the magnetic sheet 1 into close contact with the upper surface 31 of the ridge 30. In order to generate a large tension in the magnetic sheet 1, it is preferable that the first suction hole 26 is as close as possible to the convex line 30 in the X-axis direction, particularly as shown in FIGS. 4 and 5. It is preferable to contact the lower end of the strip 30 (that is, the lower end of the vertical surface 33).

  The number of the first suction holes 26 and the pitch in the Y-axis direction are not particularly limited. The magnetic sheet 1 can be appropriately set in consideration of the mechanical strength of the magnetic sheet 1 so that the magnetic sheet 1 can be brought into close contact with the upper surface 31 of the ridge 30.

  The main function of the second suction hole 27 is to fix and hold the magnetic sheet 1 to which the tension is applied by the first suction hole 26 on the base surface 21. For example, the magnetic sheet 1 is displaced with respect to the first suction hole 26 or separated from the first suction hole 26 due to vibration when the fixing base 20 is moved in the X-axis direction and the Y-axis direction by the XY drive mechanism. To prevent it. The second suction hole 27 may be disposed at a position farther in the X-axis direction than the first suction hole 26 when viewed from the ridge 30. However, according to the experiments by the present inventors, when the positions of the first suction hole 26 and the second suction hole 27 are shifted in the Y-axis direction, the magnetic sheet 1 is sucked into the second suction hole 27. Tension is applied to the magnetic sheet 1, and this tension acts directly on the portion on the upper surface 31 of the magnetic sheet 1, so that the magnetic sheet 1 is closely attached to the upper surface 31, such as wrinkles on the upper surface 31. Confirmed that it may be difficult. Therefore, as in the above example, the second suction hole 27 is positioned on the opposite side of the first suction hole 26 from the ridges 30 in the Y-axis direction of the first suction hole 26 and the second suction hole 27. It is preferable to arrange so that the positions coincide. Therefore, in this preferable arrangement, the first suction hole 26 and the second suction hole 27 are arranged side by side in a pair in the X-axis direction.

  The number of the second suction holes 27, the pitch in the Y-axis direction, and the distance in the X-axis direction from the ridges 30 of the second suction holes 27 are not particularly limited. The magnetic sheet 1 is appropriately set so that the magnetic sheet 1 can be brought into close contact with the upper surface 31 and the magnetic sheet 1 is not displaced even if the fixing base 20 is moved in the X-axis direction and the Y-axis direction.

  The plan view shape (the shape viewed from above in parallel with the Z axis) of the first suction hole 26 and the second suction hole 27 is a circle in the above example, but is not limited to this, for example, along the Y axis direction. An arbitrary shape such as a slot shape can be selected. The opening diameters of the first suction hole 26 and the second suction hole 27 are not particularly limited. However, if the opening diameter is too small, the force for sucking the magnetic sheet 1 in the suction holes 26 and 27 is reduced. Accordingly, since the first suction hole 26 cannot generate sufficient tension on the magnetic sheet 1, it is difficult to bring the magnetic sheet 1 into close contact with the upper surface 31. Further, in the second suction hole 27, the magnetic sheet 1 is displaced by vibration when the fixed base 20 is moved. Conversely, if the opening diameter is too large, the magnetic sheet 1 is sucked into the suction holes 26 and 27 and wrinkles are generated in the magnetic sheet 1. Therefore, in the first suction hole 26, it becomes difficult to make the magnetic sheet 1 adhere to the upper surface 31, or a sufficient tension cannot be generated on the magnetic sheet 1. Further, in the second suction hole 27, the magnetic sheet 1 may be displaced by vibration when the fixed base 20 is moved. Therefore, in general, the opening diameters of the first suction hole 26 and the second suction hole 27 are 0.5 mm or more and 2.5 mm or less (more preferably 2 mm or less) when the opening shape is circular. Preferably, when the opening shape is a slot shape along the Y-axis direction, the opening width in the X-axis direction is preferably 0.5 mm or more and 1 mm or less. In the above embodiment, the first suction hole 26 and the second suction hole 27 are circular with a diameter of 2.0 mm.

  The suction force of the first suction hole 26 and the second suction hole 27 is not particularly limited, but is preferably set as appropriate at a gauge pressure of −300 mmHg (−40 kPa) or more. If the attractive force is too large (the gauge pressure is too low), wrinkles are generated in the magnetic sheet 1 and the magnetic sheet 1 may be damaged. If the attractive force is too small (the gauge pressure is too high), the desired attractive force with respect to the magnetic sheet 1 of the first attractive hole 26 and the second attractive hole 27 cannot be obtained, and the magnetic sheet 1 is applied to the upper surface 31 of the convex portion 30. It becomes difficult to adhere.

  Even if the second suction hole 27 is omitted depending on the physical properties of the magnetic sheet 1, the configuration of the ridges 30, the configuration of the first suction holes 26, the suction force, etc., the magnetic sheet 1 adheres to the upper surface 31 of the ridges 30. There is a case that can be made. Therefore, the second suction hole 27 can be omitted.

  The coating-type magnetic layer generally comprises a coating process in which a magnetic coating is applied onto a flexible nonmagnetic support sheet using a coater such as a die or a gravure roll, and then a smoothly processed metal roll ( In general, it is formed through a mirroring step in which the surface of the magnetic coating layer is mirrored by applying heat and pressure to the magnetic coating layer with a “calender roll”.

  The magnetic layer contains magnetic powder and a binder (binder resin).

  As the magnetic powder, it is preferable to use ferromagnetic iron-based metal magnetic powder, iron nitride-based magnetic powder, or hexagonal Ba-ferrite magnetic powder.

  As binder, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl alcohol copolymer resin, vinyl chloride-vinyl acetate-vinyl alcohol copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride It is preferable to use a polyurethane resin in combination with at least one selected from copolymer resins, vinyl chloride-hydroxyl group-containing alkyl acrylate copolymer resins, and cellulose resins such as nitrocellulose.

  In addition to the magnetic powder and binder (binder resin), fatty acids, fatty acid esters, fatty acid amides, and the like may be included as lubricants. Carbon black or an abrasive may also be included.

  The magnetic layer component is further kneaded and dispersed using an organic solvent to produce a magnetic layer coating.

  The produced magnetic layer coating material is applied onto a support sheet or nonmagnetic layer using a gravure coater or die coater and dried to form a magnetic layer on the support sheet.

  Further, a nonmagnetic layer can be provided between the magnetic layer and the support sheet as necessary. The thickness of the nonmagnetic layer is preferably 0.2 μm or more and less than 1.0 μm, and more preferably 0.8 μm or less. If the thickness of the nonmagnetic layer is less than 0.2 μm, the effect of reducing the uneven thickness of the magnetic layer and the effect of improving the durability are reduced. The recording capacity per roll is reduced.

  Nonmagnetic powders used for the nonmagnetic layer include titanium oxide, iron oxide, and aluminum oxide. Iron oxide alone or a mixed system of iron oxide and aluminum oxide is preferably used.

  As the binder and lubricant used for the nonmagnetic layer, the same materials as those used for the magnetic layer can be used.

  The produced nonmagnetic layer coating material is applied to a support sheet using a gravure coater or a die coater, and dried to form a nonmagnetic layer on the support sheet.

  The thickness of the magnetic layer thus formed is preferably 10 nm or more and less than 100 nm when a nonmagnetic layer is provided between the magnetic layer and the support sheet. Moreover, when not providing a nonmagnetic layer, 100 nm or more and 5 micrometers are preferable.

  Further, the smoothness of the magnetic layer is preferably 10 nm or less, and more preferably 5 nm or less in terms of centerline average roughness (Ra).

  There are three main defects that occur on the surface of the magnetic layer formed in this way: protrusions, missing paint, and dents. Protrusions are mainly caused by the fact that aggregates in the magnetic paint have not been removed by the filter in the process of reaching the coater. The paint loss mainly occurs due to poor tension adjustment of the support sheet or clogging of the die slit when a die coater is used. The dent is mainly caused by dirt or scratches on the surface of the calendar roll used in the mirroring process.

  If these defects are detected in an upstream process as much as possible in the magnetic recording tape manufacturing process and appropriately dealt with, the generation of defective products can be reduced, and waste of materials and time can be reduced.

  Therefore, in the present invention, the magnetic sheet on which the surface of the magnetic layer is observed is preferably a magnetic sheet immediately after the coating process or a magnetic sheet just after the mirroring process. If protrusions are found on the surface of the magnetic layer of the former magnetic sheet, it is preferable to replace the filter through which the magnetic paint on the upstream side of the coater passes, and if a missing paint is found, adjust the tension of the support sheet. It is preferable to clean or replace the die. If a dent is found on the surface of the magnetic layer of the latter magnetic sheet, it is preferable to clean or replace the calendar roll used in the mirroring step. Thus, by appropriately dealing with the found defects, quality control can be performed, and a decrease in yield can be prevented.

  Also, record the positions where protrusions, paint omissions and dents are detected, eliminate the corresponding parts after cutting into tape, and flow only the parts without protrusions, paint omissions or dents to the downstream process, so that the protrusions and paints It is possible to prevent the magnetic tape including the dent and the dent from being shipped as a product. In this case, as a method of recording the position, the position may be recorded directly on the magnetic sheet, or may be recorded on the computer 46 to which the video signal photographed by the camera 45 is output.

  Furthermore, if a defect is found that adversely affects the quality of the magnetic tape, if the next process is stopped on the magnetic sheet, it is possible to avoid performing a useless process, resulting in loss of materials and time. Can be reduced.

According to the present invention, since the tension is applied to the magnetic sheet 1 so as to be in close contact with the upper surface 31 of the ridge 30, the surface of the magnetic layer is substantially flat even in a magnetic sheet having low mechanical strength (no so-called stiffness). Can be held in a shape. Therefore, the total thickness is 20 μm or less, and the total thickness is 9.0 μm or less that is generally used for a high-capacity magnetic tape of 400 GB / turn or more in high-density recording exceeding 0.5 Gbit / in ^2. When the present invention is applied to a sheet, the effects of the present invention are remarkably exhibited.

  The nonmagnetic support sheet to which the magnetic layer of the magnetic sheet is applied is not particularly limited, and for example, biaxially stretched polyethylene terephthalate film, polyethylene naphthalate film, aromatic polyamide film, aromatic polyimide film, etc. are used. be able to.

(Embodiment 2)
FIG. 6 is a cross-sectional view along the XZ plane of the ridge 30 of the fixing base 20 according to the second embodiment of the present invention. The ridge 30 of the second embodiment does not include the vertical surface 33 (see FIG. 4) that the ridge 30 of the first embodiment has.

  The inclination angle θ of the inclined surface 33 with respect to the horizontal plane is set in the same manner as described in the first embodiment. The lower end of the inclined surface 33 is connected to the base surface 21. The first suction hole 26 is preferably as close as possible to the lower end of the inclined surface 33 (lower end of the ridge 30), and in particular, as shown in FIG. 6, is preferably in contact with the lower end of the inclined surface 33. .

  Also in the second embodiment, the magnetic sheet is attracted to the first suction hole 26 and the second suction hole 27 so that the application sheet is brought into close contact with the upper surface 31 of the ridge 30, and the surface of the magnetic layer of the magnetic sheet is observed. it can. As a result, the same effects as those of the first embodiment are obtained. However, in the second embodiment that does not include the vertical surface 33, the tension generated in the magnetic sheet is likely to be smaller than in the first embodiment that includes the vertical surface 33.

  The second embodiment is the same as the first embodiment except for the above. The description of the first embodiment is also applied to the second embodiment.

(Embodiment 3)
FIG. 7 is a plan view of the fixed base 20 according to the third embodiment of the present invention. FIG. 8 is an enlarged cross-sectional view of the protrusion 30 of the fixing base 20 along the plane including the line 8-8 in FIG. In the third embodiment, grooves (concave portions) 28 extending along the Y-axis direction are formed on both sides of the ridge 30 in the X-axis direction. As shown in FIG. 8, the inner wall surface 33 on the ridge 30 side of the groove 28 functions as the vertical surface 33 (see FIG. 4) of the ridge 30 described in the first embodiment. The first suction hole 26 and the second suction hole 27 are formed on the bottom surface of the groove 28. As described in the first embodiment, the first suction hole 26 is preferably in contact with the lower end of the ridge 30 (that is, the lower end of the vertical surface 33).

  In the third embodiment, when the magnetic sheet 1 is sucked into the first suction hole 26 and the second suction hole 27, the magnetic sheet 1 enters the groove 28 as shown in FIG. Therefore, a larger tension can be generated in the magnetic sheet 1 than in the first embodiment. As a result, the adhesion of the magnetic sheet 1 to the upper surface 31 of the ridge 30 is improved, so that the surface of the magnetic layer can be observed more accurately in a shorter time.

  The third embodiment is the same as the first embodiment except for the above. The description of the first embodiment is also applied to the third embodiment.

  Also in the third embodiment, the vertical surface 33 can be omitted as described in the second embodiment. In this case, the inclined surface 33 extends to the bottom surface of the groove 28.

  The above first to third embodiments are merely examples. The present invention is not limited to the first to third embodiments, and can be changed as appropriate.

  For example, in the first to third embodiments, the inclined surface 32 is a flat surface, but may be an arbitrary curved surface such as a cylindrical surface convex outward.

  In the first to third embodiments, the case where the coated sheet is a magnetic sheet has been described. However, the present invention is used for known applications such as optical, packaging, and various industrial applications other than the magnetic sheet. The present invention can be applied to any coating sheet having a coating layer. Regardless of the application of the coated sheet, when the present invention is applied to a coated sheet having a total thickness of 20 μm or less, further 9 μm or less, particularly 6 μm or less, and a low mechanical strength (no so-called stiffness), the effects of the present invention are It is preferable because it is remarkably expressed.

  The application field of the present invention is not particularly limited, but according to the present invention, the defect inspection of the coated surface can be performed accurately in a short time, so that the surface property of the coated surface of the flexible coated sheet can be observed and evaluated. It can be widely used in the field of quality control. In particular, in the field of magnetic recording media having a coating type magnetic layer, it can be preferably used for quality control of the magnetic layer at the stage of the original fabric.

1 Magnetic sheet (coated sheet)
DESCRIPTION OF SYMBOLS 11 Holding stand 20 Fixing base 21 Base surface 26 1st suction hole 27 2nd suction hole 28 Groove 30 Projection 31 Projection upper surface 32 Projection inclined surface 33 Projection strip vertical surface

Claims (12)

A method of holding the application sheet on the base surface of a fixed base in order to observe the application surface of the application sheet,
The fixed base is
A ridge having a smooth upper surface protruding from the base surface and extending along the first direction;
A first suction hole formed on both sides of a second direction perpendicular to the first direction with respect to the ridge,
The application sheet is placed on the base surface so that the application surface faces away from the base surface and covers the ridges and the first suction holes,
A method of holding a coated sheet for observing a coated surface, wherein the coated sheet is sucked into the first suction hole to bring the coated sheet into close contact with the upper surface of the ridge.   The method for holding a coated sheet for observing a coated surface according to claim 1, wherein the ridge is provided with inclined surfaces adjacent to the upper surface on both sides in the second direction with respect to the upper surface.   The method for holding a coated sheet for observing a coated surface according to claim 2, wherein the ridge is provided with a vertical surface substantially perpendicular to the base surface adjacent to the inclined surface.   The said 1st suction hole is the holding method of the coating sheet for coating surface observation in any one of Claims 1-3 which is in contact with the lower end of the said protruding item | line. A groove extending along the first direction is formed in the base surface adjacent to the ridge,
The said 1st suction hole is formed in the bottom face of the said groove | channel, The holding method of the application sheet | seat for application | coating surface observation in any one of Claims 1-4.   The shape of the first suction hole in plan view is a circular shape having a diameter of 2.5 mm or less or a slot shape having a width of 1 mm or less. Retention method. A second suction hole is formed at a position farther from the ridge than the first suction hole;
The method of holding a coated sheet for observation of a coated surface according to claim 1, wherein the coated sheet is sucked into the second suction hole. A groove extending along the first direction is formed in the base surface adjacent to the ridge,
The said 2nd suction hole is a holding method of the coating sheet for coating surface observation of Claim 7 currently formed in the bottom face of the said groove | channel.   The method for holding a coated sheet for observing a coated surface according to claim 7 or 8, wherein the shape of the second suction hole in plan view is a circular shape having a diameter of 2.5 mm or less or a slot shape having a width of 1 mm or less.   The method for holding a coated sheet for observation of a coated surface according to any one of claims 1 to 9, wherein the surface roughness of the upper surface of the ridge satisfies Ra ≦ 0.05 μm and Rmax ≦ 0.2 μm.   The method for holding a coated sheet for observation of a coated surface according to claim 1, wherein the total thickness of the coated sheet is 20 μm or less.   The method for holding a coated sheet for observation of a coated surface according to claim 1, wherein the coated sheet is a magnetic recording medium sheet.

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