JP2008140504A - Inspecting apparatus and inspecting method for magnetic tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection apparatus and an inspection method capable of accurately and simply detecting a radial defect in a magnetic tape wound around a tape reel. <P>SOLUTION: The inspection apparatus and the inspection method for inspecting the magnetic tape T wound around the tape reel 2 stored in a magnetic tape cartridge C comprise: a means 12 for withdrawing the magnetic tape T; an irradiation section 16 for applying light to a region to be inspected in the magnetic tape T wound around the tape reel 2; an imaging section 18 for imaging the region to be inspected along the longitudinal direction of the magnetic tape T by withdrawing the magnetic tape T; and a signal processing section 28 for calculating defects at the region to be inspected based on data imaged by the imaging section 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetic tape inspection apparatus and inspection method capable of accurately inspecting a winding state of a magnetic tape while being wound around a magnetic tape cartridge.

  2. Description of the Related Art Conventionally, magnetic tape cartridges compliant with LTO (Linear Tape Open) standards and DLT (Digital Linear Tape) standards are known as external recording media for data backup such as computers. A magnetic tape cartridge is configured to accommodate a tape reel on which a magnetic tape is wound. At the time of magnetic recording / reproducing, the magnetic tape cartridge is loaded into a magnetic recording / reproducing device (drive device), and the magnetic tape is pulled out to a machine reel of the drive device to run. The magnetic head is used for writing on the magnetic tape.

  In recent years, in order to increase the recording capacity of a magnetic tape, the capacity has been increased, and the thickness of the magnetic tape has been reduced to increase the number of turns that can be wound around a tape reel having the same diameter as conventional ones. Then, when there is a defect such as a minute deformation on the tape edge, when the magnetic tape is wound around the tape reel, the thickness of the magnetic tape wound on the defective portion becomes thick, so-called so-called winding thickening phenomenon. Will occur. When the winding diameter of the magnetic tape reaches a predetermined value or more, there is a problem that defects are generated radially from the center of the winding of the magnetic tape toward the winding surface on the outer side in the radial direction when viewed in the width direction of the magnetic tape. Such radial defects are localized winding distortion due to the winding state of the magnetic tape around the reel or the change in the thickness of the end of the magnetic tape. This causes a problem that an error occurs because magnetic recording / reproduction cannot be performed accurately.

  As a conventional method for detecting a radial defect generated on a magnetic tape wound around a tape reel, as shown in FIG. 7, the side surface of the tape reel 102 is wound with the magnetic tape T wound around the tape reel 102. The side surface in the width direction of the magnetic tape wound by the detection unit 104 such as a camera is detected as a surface to be inspected (see, for example, Patent Document 1 below).

JP-A-2005-326312

By the way, the inspection method is performed before the magnetic tape is wound around the tape reel in the manufacturing process of the magnetic tape cartridge and incorporated into the cartridge case of the magnetic tape cartridge, and the cartridge case of the magnetic tape cartridge is manufactured. It is employed in a manufacturing process in which a process of incorporating a tape reel on which a magnetic tape is wound around a cartridge is performed. However, at present, when a cartridge case of a magnetic tape cartridge is manufactured in order to ensure flexibility in the production process by manufacturing the cartridge case and the magnetic tape in separate processes, the magnetic tape is put inside the cartridge case. The mainstream is a manufacturing process including a step of incorporating a tape reel that has not been wound in advance and then winding the magnetic tape around the tape reel of the cartridge case. Thus, in the current manufacturing process, since the tape reel is accommodated in the cartridge case, the conventional inspection method cannot be employed. Further, in the conventional inspection method, when the tape reel is not a transparent material, it is impossible to inspect by the detection unit from the side surface of the tape reel.
Further, radial defects on the magnetic tape wound around the tape reel are extremely difficult to detect by visual inspection.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic tape inspection apparatus and inspection method capable of accurately and easily detecting a radial defect of a magnetic tape wound around a tape reel. There is to do.

The above object of the present invention is achieved by the following configurations.
(1) An inspection apparatus for inspecting a magnetic tape wound on a tape reel accommodated in a magnetic tape cartridge, wherein the magnetic tape is wound around the tape reel, and a drawing means for pulling out the magnetic tape. Based on the illumination unit that irradiates light to the region to be inspected, the imaging unit that pulls out the magnetic tape and images the region to be inspected along the longitudinal direction of the magnetic tape, and the imaging data captured by the imaging unit And a signal processing unit for calculating a defect in the inspection area.
(2) The signal processing unit measures a luminance distribution with respect to a position in the width direction of the magnetic tape based on a luminance signal of imaging data captured by the imaging unit. Inspection equipment.
(3) The inspection apparatus according to (1) or (2), wherein the imaging unit is a CCD line sensor.
(4) The inspection apparatus according to any one of (1) to (3), wherein the illumination unit is a linear light source having a longitudinal dimension along a width direction of the magnetic tape.
(5) An inspection method for inspecting a magnetic tape wound on a tape reel housed in a magnetic tape cartridge, wherein light is applied to a region to be inspected of the magnetic tape in a state wound on the tape reel. The magnetic tape is pulled out by the pulling means, the inspection area is imaged by the imaging unit along the longitudinal direction of the magnetic tape, and the defect of the inspection area is determined based on the imaging data captured by the imaging section. An inspection method characterized by being calculated by a signal processing unit.
(6) The inspection method according to (5), wherein the signal processing unit measures a luminance distribution with respect to a position in the width direction of the magnetic tape based on a luminance signal of the imaging data.
(7) The signal processing unit calculates luminance information in a one-dimensional direction corresponding to a longitudinal direction of the magnetic tape using a binarization process based on a two-dimensional image captured by the imaging unit. The inspection method according to (5) or (6) above.
(8) The inspection method according to any one of (5) to (7), wherein the imaging unit is a CCD line sensor.
(9) The inspection method according to any one of (5) to (8), wherein the illumination unit is a line light source having a longitudinal dimension along a width direction of the magnetic tape.

  According to the present invention, in a state where the magnetic tape is wound around the tape reel, the magnetic tape is pulled out, the light is irradiated to the inspection area along the longitudinal direction, and the surface of the magnetic tape is imaged by the reflected light of the light. The image of the inspection area is calculated based on the captured image data. When there is a defect on the surface of the magnetic tape, the brightness of the reflected light changes, so by scanning the imaging unit along the longitudinal direction of the magnetic tape, the region where the brightness changes with respect to the longitudinal direction of the magnetic tape is specified. It is possible to detect radial defects that occur periodically in the longitudinal direction of the magnetic tape. For this reason, it is possible to exclude those that are curved in the width direction of the magnetic tape and that do not become defects on the product that are constantly distorted in the longitudinal direction of the magnetic tape, only radial defects. Can be accurately detected.

  ADVANTAGE OF THE INVENTION According to this invention, the inspection apparatus and inspection method of a magnetic tape which can detect the radial defect of the magnetic tape wound around the tape reel correctly and simply can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating the configuration of a magnetic tape inspection apparatus according to the present invention.
The magnetic tape cartridge C has a configuration in which the tape reel 2 around which the magnetic tape T is wound is accommodated in the cartridge case 1. The cartridge case 1 is formed with a shutter portion 3 that is opened when the magnetic tape T is led out.

  The magnetic tape T of the present embodiment is a long strip member having a magnetic layer in which magnetic information for performing magnetic recording and reproduction can be written. The structure of the magnetic tape T can be the same as the conventional one. For example, the magnetic tape for magnetically recording information on one surface of a support made of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). A layer, a protective layer that protects the magnetic layer from deterioration and wear, and a lubricating layer that improves running durability and corrosion resistance by applying a lubricant are laminated in this order. Further, if necessary, an undercoat layer (not shown) for enhancing the surface properties and gas barrier properties and an underlayer for enhancing the recording characteristics by controlling the crystal orientation of the magnetic layer are provided on the surface of the support. May be. A back coat layer is formed on the opposite surface of the magnetic layer with the support interposed therebetween. The thickness of the magnetic tape is generally about 6 μm to 8 μm at present, but the number of turns wound around the tape reel 2 can be reduced by reducing the thickness in response to the recent demand for higher recording capacity. There is a configuration in which

  When magnetic recording / reproduction is performed on the magnetic tape T of the magnetic tape cartridge C, the magnetic tape cartridge C is loaded into a drive device (not shown), and the magnetic tape is pulled out by a loading member built in the drive device and wound on a machine reel. At the same time, magnetic information is written to and read from the magnetic layer of the magnetic tape T by the magnetic recording head. At this time, if the magnetic tape T is directly pulled out by the loading member, sufficient mechanical strength cannot be ensured because the magnetic tape MT is thin. Therefore, the magnetic tape T is joined to the leading end in the pulling direction of the magnetic tape T and the magnetic tape T The leader tape, which is formed sufficiently thicker than the above, is pulled out by a loading member.

  The thickness of the leader tape is about 120 μm, which is higher than that of the magnetic tape T. However, the end portion of the leader tape may be subjected to a process of reducing the thickness in the vicinity of the end portion by a cutting process in order to avoid an increase in thickness difference when bonded to the magnetic tape T.

  The inspection apparatus 10 of the present embodiment winds the winding unit 12 such as a machine reel that winds the leader tape of the magnetic tape T drawn from the opened shutter unit 3 of the magnetic tape cartridge C, and the winding unit 12. In this case, a guide roller 14 for guiding the traveling magnetic tape T is provided. In the present invention, the winding unit 12 functions as a pulling unit for pulling out the magnetic tape T from the magnetic tape cartridge C. In the present embodiment, the magnetic tape T is pulled out by winding the magnetic tape T around the winding portion 12. However, even if the magnetic tape T is not wound up, it can be pulled out linearly from the magnetic tape cartridge C. Good.

  The winding portion 12 has a substantially disk shape, and the opening formed at the end portion of the leader tape is locked to the locking portion formed in a convex shape on a part of the peripheral surface, as shown in FIG. The leader tape and the magnetic tape T are wound up by rotating in the direction. The rotation speed and rotation speed of the winding unit 12 can be appropriately controlled by a control unit described later.

  The inspection apparatus 10 exposes a predetermined magnetic tape T in a state of being wound around a tape reel 2 housed in the cartridge case 1 exposed through an opening portion of the cartridge case 1 where the shutter portion 3 is opened. An illumination unit 16 for irradiating light is provided in the inspection area. As the illumination unit 16, for example, a linear light source such as a long fluorescent lamp can be used.

  Further, the inspection apparatus 10 includes an imaging unit 18 that captures an image of a region to be inspected on the magnetic tape exposed through the opening of the cartridge case 1. As the imaging unit 18, for example, a CCD line sensor can be used.

  FIG. 2 is a diagram illustrating the positions of the illumination unit and the imaging unit with respect to the magnetic tape T in the inspection apparatus of the present embodiment. As shown in FIG. 2, the illumination unit 16 is arranged so that the longitudinal direction thereof is substantially parallel to the width direction of the magnetic tape T when the recording surface of the magnetic tape T is viewed in plan. The imaging unit 18 is arranged at an interval with respect to the traveling direction of the magnetic tape T (the direction indicated by the arrow in FIG. 2) with respect to the illumination unit 16. When the imaging unit 18 uses a CCD line sensor, the imaging element array is provided so as to be substantially parallel to the width direction of the magnetic tape T. At this time, each imaging element scans along the longitudinal direction of the magnetic tape T by running the magnetic tape T at the time of inspection. Here, the inspection apparatus 10 may scan the imaging unit 18 while pulling out the magnetic tape T as in the present embodiment, or may scan the imaging unit 18 with the magnetic tape T stopped.

 Here, the normal line direction of the portion where the illumination light strikes the magnetic tape T wound around the tape reel is indicated by a one-dot chain line N in FIG. When the angle between the imaging direction of the imaging unit 18 and the normal direction N is A1, and the angle between the light direction of the illumination unit 16 and the normal direction N is A2, A1 is 5 ° to 30 °, and A2 Is preferably 5 ° to 30 °.

  Next, a control system of the inspection apparatus according to this embodiment will be described. As illustrated in FIG. 1, the inspection apparatus 10 includes an illumination driving unit 22 that controls driving of the illumination unit 16, an imaging driving unit 24 that controls imaging of the imaging unit 18, and the illumination driving unit 22 and the imaging driving unit 24. A control unit 26 for controlling driving is provided. In addition, the inspection apparatus 10 acquires information of imaging data captured by the imaging unit 18 and performs signal processing, and a winding drive unit that can control the number of rotations and the rotation speed of the winding unit 12. 32.

  FIG. 3 is a flowchart for explaining the procedure of the inspection method of the present embodiment. In the following description of the inspection method, the inspection apparatus shown in FIG. 1 will be described as an example. The inspection apparatus used in the inspection method of the present embodiment is not particularly limited, but can be preferably implemented by using the above-described inspection apparatus.

  First, the magnetic tape cartridge C is installed on a holding member such as a cartridge holder of the inspection apparatus 10. Then, the shutter portion 3 of the cartridge case 1 is opened, the leader tape formed on the tip portion of the magnetic tape T is pulled out by a loading mechanism (not shown), etc., and fixed to the winding portion 12 of the inspection apparatus 10 (step S1). As the loading mechanism, the same mechanism as that used in the magnetic recording / reproducing apparatus can be used.

  After the magnetic tape T is pulled out, an illumination control signal is output from the control unit 26 to the illumination drive unit 22, and light is irradiated from the illumination unit 16 to the inspection area of the magnetic tape T wound around the tape reel 2. At this time, a winding control signal is output from the control unit 26 to the winding driving unit 32, the winding unit 12 is driven, and winding of the magnetic tape T from the tape reel 2 of the magnetic tape cartridge C is started. Further, an imaging control signal is output from the control unit 26 to the imaging drive unit 24, and the inspection area is imaged by the relative movement of the imaging unit 18 with respect to the traveling magnetic tape T (step S2). At this time, the magnetic tape T is imaged along the longitudinal direction (direction in which the magnetic tape T is wound and traveled) by the line sensor provided in the imaging unit 18, and the imaging data is detected (step S3).

FIG. 4 is a diagram illustrating a state when the magnetic tape is imaged. FIG. 4 shows an example in which a defect E has occurred in the magnetic tape T. In the inspection of the magnetic tape T of the present embodiment, the imaging unit 18 captures an image of one turn of the tape reel 2 on the magnetic tape T, and acquires imaging data.
The length of the magnetic tape T to be imaged at the time of inspection is not particularly limited. However, by imaging the length L of at least one turn with respect to the longitudinal direction of the magnetic tape T, the radial tape generated periodically in the longitudinal direction. It is possible to detect defects. This is preferable because it is not necessary to perform imaging over the entire length of the magnetic tape T, and inspection can be performed efficiently in a short time. At the time of inspection, the imaging elements of the imaging unit 18 are arranged at equal intervals with respect to the width dimension W of the magnetic tape T, and are scanned linearly while moving relative to the longitudinal direction of the magnetic tape T. Get luminance data. As described above, the imaging unit 18 detects a defect based on the change in the luminance data with respect to the longitudinal direction of the magnetic tape T.

  The magnetic tape T has a problem as a product due to the characteristics of magnetic recording / reproduction, such as radial defects, and although slight deformation is recognized, there is no problem in terms of magnetic recording / reproduction, and it is detected as a defect. Some things are not necessary. For example, as shown in FIG. 5, in a state where the magnetic tape T is wound around a tape reel, a deformation (a so-called sea cucumber deformation) in which a minute curve W occurs in the width direction of the magnetic tape T occurs. There is a case. When such deformation W occurs, since irregularities do not occur periodically in the length direction of the magnetic tape T, it does not become an obstacle to performing magnetic recording and reproduction, and is not handled as a defect. . According to the inspection method of the present embodiment, the defect is detected based on the change in the luminance data with respect to the longitudinal direction of the magnetic tape T. Therefore, the deformation as described above is not detected as a defect. Defects can be detected accurately.

  After acquiring the imaging data of the magnetic tape T, the imaging data imaged by the imaging unit 18 is output to the signal processing unit 28, and image processing of the imaging data is executed according to the processing control signal from the control unit 26. At this time, binarization processing is executed based on the luminance information included in the imaging data (step S4), and thereafter luminance data is calculated (step S5). The binarization processing performed in the present embodiment is a process in which the luminance of one pixel is displayed in a certain gradation (for example, 256 gradations), and the original image displayed at a certain gradation is 1 above and below it. This is a process of setting 0 to 1 for black and 0 for white.

  FIG. 6 shows an example of luminance data. In the present embodiment, the luminance value for the position in the width direction of the magnetic tape T is used as the luminance data. As shown in FIG. 6, by analyzing the luminance distribution for each position in the width direction of the magnetic tape T, it is determined that a defect has occurred in a portion where high luminance is concentrated. The position in the width direction of the magnetic tape T in which this defect has occurred can be output to the control unit 26 or other display device (not shown). In this way, the position of the radial defect in the longitudinal direction of the magnetic tape T can be specified.

  According to the above embodiment, in a state where the magnetic tape T is wound around the tape reel 2, the magnetic tape T is wound up, and light is irradiated to the inspection area along the longitudinal direction. The surface of the magnetic tape T is imaged by the imaging unit 18, and the defect in the inspection area is calculated based on the captured image data. When there is a defect on the surface of the magnetic tape T, the brightness of the reflected light changes. Therefore, by scanning the imaging unit 18 along the longitudinal direction of the magnetic tape T, the brightness with respect to the longitudinal direction of the magnetic tape T is changed. A site can be identified, and radial defects that occur periodically in the longitudinal direction of the magnetic tape T can be detected. For this reason, it is possible to exclude those that are curved in the width direction of the magnetic tape T and do not cause defects on the product that are constantly distorted in the longitudinal direction of the magnetic tape T. Only defects can be accurately detected.

It is a figure explaining the structure of the inspection apparatus of the magnetic tape concerning this invention. It is a figure which shows the position of the illumination part with respect to a magnetic tape, and an imaging part in a test | inspection apparatus. It is a flowchart explaining the procedure of an inspection method. It is a figure which shows a state when a magnetic tape is imaged. It is a figure which shows an example of the deformation | transformation seen in the magnetic tape wound by the tape reel. It is a figure which shows an example of luminance data. It is a figure which shows the inspection method of the conventional magnetic tape.

Explanation of symbols

2 Tape reel 10 Inspection device 12 Winding part (drawing means)
16 Illumination unit 18 Imaging unit 28 Signal processing unit C Magnetic tape cartridge T Magnetic tape

Claims (9)

An inspection device for inspecting a magnetic tape wound on a tape reel housed in a magnetic tape cartridge,
Drawer means for pulling out the magnetic tape;
An illuminating unit for irradiating light to an inspection area of the magnetic tape in a state wound on the tape reel;
An imaging unit that pulls out the magnetic tape and images the inspection area along the longitudinal direction of the magnetic tape;
An inspection apparatus comprising: a signal processing unit that calculates a defect in the inspection region based on imaging data captured by the imaging unit.   The inspection apparatus according to claim 1, wherein the signal processing unit measures a distribution of luminance with respect to a position in the width direction of the magnetic tape based on a luminance signal of imaging data captured by the imaging unit.   The inspection apparatus according to claim 1, wherein the imaging unit is a CCD line sensor.   The inspection apparatus according to claim 1, wherein the illumination unit is a line light source having a longitudinal dimension along a width direction of the magnetic tape. An inspection method for inspecting a magnetic tape wound on a tape reel housed in a magnetic tape cartridge,
Light is applied to the area to be inspected of the magnetic tape wound around the tape reel, the magnetic tape is pulled out by a pulling means, and the area to be inspected along the longitudinal direction of the magnetic tape is picked up by the imaging unit. An inspection method comprising: picking up an image, and calculating a defect in the region to be inspected by a signal processing unit on the basis of imaging data captured by the imaging unit.   The inspection method according to claim 5, wherein the signal processing unit measures a luminance distribution with respect to a position in the width direction of the magnetic tape based on a luminance signal of the imaging data.   The signal processing unit calculates luminance information in a one-dimensional direction corresponding to a longitudinal direction of the magnetic tape using a binarization process based on a two-dimensional image captured by the imaging unit. Item 7. The inspection method according to Item 5 or 6.   The inspection method according to claim 5, wherein the imaging unit is a CCD line sensor.   The inspection method according to claim 5, wherein the illumination unit is a line light source having a longitudinal dimension along a width direction of the magnetic tape.

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