JP2011204321A - Releasing jig for substrate of magnetic disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a releasing jig for a substrate which can release a substrate closely attached to a polishing plate and can suppress flaw on a substrate surface and dirt on the substrate.SOLUTION: The releasing jig 1 for a substrate includes a body part 11 in which a through path to supply compressed air from one end is formed inside, a flat nozzle 19 which is inclined to the body part 11 and attached to another side edge side of the through path and discharges the compressed air, and a substrate receiving part 12 which receives and holds a glass substrate 14 integrated into the body part 11 side containing the flat nozzle 19 and floated from the polishing pad 13 by the compressed air discharged from the flat nozzle 19.

Description

  The present invention relates to a magnetic disk substrate peeling jig for peeling a substrate adsorbed on a polishing plate, and more particularly to a magnetic disk suitably used for peeling a glass substrate for a magnetic disk in close contact with a polishing pad in the manufacturing process of the glass substrate for a magnetic disk. The present invention relates to a substrate peeling jig.

  Currently, magnetic disks using glass substrates are widely used as recording media for hard disk devices. Magnetic disks are shaped processing steps (such as coring and chamfering) that form a plate-like glass material such as float glass on an annular glass substrate, and grinding processing steps (lapping) that adjust the thickness of the glass substrate by grinding. ) And a polishing process (end face part and main surface part) for smoothing the glass substrate by polishing process.

  FIG. 4 is a diagram illustrating an example of a double-side polishing apparatus used in the polishing process. This double-side polishing apparatus has a pair of upper and lower polishing surface plates 41 and 42, and polishes the glass substrate 44 with a polishing pad 43 of a soft polisher (suede) attached to the surfaces of these polishing surface plates 41 and 42. In this double-side polishing apparatus, a disk-shaped carrier 45 that holds a glass substrate 44 is installed between the polishing surface plates 41 and 42, and pressure is applied between the upper and lower polishing surface plates 41 and 42 to sandwich the carrier 45, The upper polishing surface plate 42 and the lower polishing surface plate 41 are rotated in the reverse direction, and both main surfaces of the glass substrate 44 are polished while supplying an abrasive. In such a planetary gear mechanism, a carrier 45 is disposed between a sun gear 46 provided at the center of the lower polishing surface plate 41 and an internal gear 47 provided on the outer periphery of the lower polishing surface plate 41. The At this time, the tooth portion 48 provided on the outer periphery of the carrier 45 meshes with the sun gear 46 and the internal gear 47. Therefore, by rotating the upper polishing surface plate 42 and the lower polishing surface plate 41 in the reverse direction, the carrier 45 revolves while rotating. The glass substrate 44 is held in the hole 45 a of the carrier 45.

  By the way, in the polishing process using the double-side polishing apparatus, a phenomenon occurs in which the polished glass substrate and the polishing pad are in close contact with each other. For this reason, in the polishing process, the glass substrate is directly grasped and peeled off with a gloved hand, or a jig with a sharp tip or a thin tip is inserted between the glass substrate and the polishing pad. Thus, the glass substrate is peeled from the polishing pad.

  Further, as a jig for peeling a glass substrate in close contact with a polishing pad, a substrate holding and fixing jig provided with a suction cup for adsorbing the glass substrate has also been proposed (for example, see Patent Document 1). In the substrate holding and fixing jig described in Patent Document 1, with the suction cup applied to the glass substrate, the inside of the suction cup is evacuated to adsorb the glass substrate and peel the glass substrate from the polishing pad. The glass substrate adsorbed by the suction cup can be removed from the suction cup by introducing air into the suction cup.

JP 2005-8353 A

  However, there is a problem that the glass substrate and the polishing pad are damaged when the glass substrate in close contact with the polishing pad is directly peeled off using a hand or a jig. Further, when the glass substrate is adsorbed and peeled off, there is a problem that dirt adheres to the place where the suction cup contacts, and when the adsorbing time becomes longer, the adsorbed place dries early and the dirt adheres.

  This invention is made in view of this point, and provides the board | substrate peeling jig | tool which can peel the board | substrate which contact | adhered to the grinding | polishing board, and can suppress the damage | wound of a substrate surface, and adhesion of the stain | pollution | contamination to a board | substrate. With the goal.

  The substrate peeling jig according to the present invention has a main body portion in which a through passage to which compressed air is supplied from one end is formed, and is inclined to the other end side of the through passage with respect to the main body portion. A nozzle for discharging, and a substrate receiving portion for receiving and holding a substrate that is integrated with the main body side including the nozzle and is lifted from the polishing plate by compressed air discharged from the nozzle. .

  According to this configuration, the substrate that is in close contact with the polishing plate can be peeled off without contacting the substrate surface by discharging compressed air. Further, since the substrate lifted from the polishing plate is received and held by the substrate receiving portion, the contact between the substrate peeled off from the polishing plate and the polishing plate can be avoided. Therefore, scratches on the substrate surface and adhesion of dirt to the substrate can be suppressed.

  In the base material peeling jig according to the present invention, the main body portion may include a grip portion in which a part of the through passage is formed, an opening / closing means provided in the through passage, and one end portion of the grip portion. And a lever member that opens and closes the opening / closing means in response to a lever turning operation, and a connecting member that connects the grip portion and the nozzle, and the substrate receiving portion is lifted from the polishing plate. A roll member that is inserted into the central opening of the substrate and holds the substrate, and a base of the roll member so that the tip of the roll member is positioned at a predetermined distance in the horizontal direction from the tip of the nozzle. And a support member for supporting the end portion.

  According to this configuration, the discharge of the compressed air can be switched by the turning operation of the lever member. Moreover, since the front-end | tip part of a roll member inserts in the center opening part of a board | substrate and hold | maintains a board | substrate, the board | substrate which floated up from the grinding | polishing board can be supported from the lower surface side of a center opening part.

  In the substrate peeling jig according to the present invention, it is preferable that the roll member is a roll brush. With this configuration, the center portion of the substrate can be supported from the lower surface side by the bristles of the roll brush, so that the attachment of scratches to the substrate can be suppressed.

  In the substrate peeling jig according to the present invention, the roll member is preferably a resin sponge. With this configuration, since the center portion of the substrate can be supported from the end surface by the outer peripheral surface of the resin sponge, it is possible to suppress the attachment of scratches to the substrate.

  In the substrate peeling jig according to the present invention, it is preferable that the nozzle is a flat nozzle having a width corresponding to an outer diameter of the substrate. With this configuration, compressed air corresponding to the width of the substrate can be discharged, so that the substrate and the polishing pad can be efficiently separated.

  The pressure control mechanism of the present invention is provided in a compressed air supply path from a compressed air supply source to the magnetic disk substrate peeling jig, and converts pressure primary means of compressed air into a predetermined secondary pressure. An opening / closing valve provided on the upstream side of the pressure control means in the compressed air supply path and restricting the amount of compressed air supplied by adjusting a valve opening degree.

  According to this configuration, for example, the primary pressure of the compressed air supplied from the compressed air supply source is adjusted to a predetermined secondary pressure by the pressure control means, and the opening degree of the open / close valve is set to the magnetic disk substrate. By controlling the flow rate of compressed air supplied to the peeling jig per unit time to be smaller than the discharge amount of compressed air per unit time of the magnetic disk substrate peeling jig, it is discharged from the magnetic disk substrate peeling jig. The amount of compressed air to be reduced can be made the minimum amount necessary for peeling the substrate. Further, even when the release of the lever member is delayed, the discharge of excessive compressed air to the substrate can be suppressed, so that the drying of the substrate can be suppressed and the adhesion of dirt to the substrate surface can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the board | substrate peeling jig | tool which can peel the board | substrate closely_contact | adhered with the grinding | polishing board and can suppress the adhesion | attachment of the damage | wound of a substrate surface and a board | substrate can be provided.

(A) is a top view of the board | substrate peeling jig | tool which concerns on embodiment of this invention, (b) is a side view of (a). It is a figure which shows the compressed air supply path | route of the board | substrate peeling jig which concerns on embodiment of this invention. (A), (b) is an expanded sectional view of the board | substrate receiving part of the board | substrate peeling jig which concerns on embodiment of this invention. It is a figure which shows an example of a grinding | polishing processing apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Fig.1 (a) is a top view of the board | substrate peeling jig | tool which concerns on embodiment of this invention, FIG.1 (b) is a side view of Fig.1 (a). As shown in FIGS. 1 (a) and 1 (b), a substrate peeling jig 1 includes a main body 11 in which a through passage for supplying compressed air is formed and compressed air is supplied to one end of the through passage. And a substrate receiving part 12 integrated with the main body part 11. The substrate peeling jig 1 discharges compressed air to the boundary between the polishing pad 13 and the glass substrate 14 to lift the glass substrate 14 from the polishing pad 13 and holds the glass substrate 14 with the substrate receiving portion 12. In addition, in FIG.1 (b), the board | substrate receiving part 12 has shown about the AA arrow cross section.

  A connecting portion 15 connected to a compressed air supply source via a compressed air supply system is provided at one end of the through passage formed inside the main body portion 11. An open / close valve (not shown) for opening and closing the flow path is provided between the connection portion 15 and the open end portion 16 in the middle of the through passage.

  The main body 11 has a gripping part 17 in which a part of the through passage is formed. An operation lever 18 having one end rotatably supported is attached to the grip 17. The operation lever 18 is biased by a spring (not shown) in a direction in which the free end side is separated from the gripping portion 17. By turning the operation lever 18, the open / close valve in the through passage can be opened and closed.

  A flat nozzle 19 is connected to the open end 16 via a connector 20 having a through hole, and the inside of the through passage and the inside of the flat nozzle 19 are communicated with each other. One end of the connector 20 is connected to the main body 11 side, and the other end is connected to the flat nozzle 19. The flat nozzle 19 is provided with a cylindrical connecting portion 19a at one end on the side of the connecting tool 20, and a flat discharge port 19b at the other end. The opening between the discharge ports 19b has a width corresponding to the outer diameter of the glass substrate 14.

  The flat nozzle 19 is connected to be inclined with respect to the plane F <b> 1 including the rotation direction of the operation lever 18. The inclination angle of the flat nozzle 19 is not particularly limited as long as the glass substrate 14 can be peeled from the polishing pad 13 by discharging compressed air, but is preferably about 35 to 45 degrees from the plane F1. In addition, the flat nozzle 19 may be connected via the coupler 20, and it is good also as a structure directly connected to the open end part 16 of the main-body part 11. FIG.

  A substrate receiving portion 12 is fixed to the flat nozzle 19 via a nozzle adapter 21. The nozzle adapter 21 has a tapered surface 21a. The tapered surface 21a is brought into contact with the upper surface of the flat nozzle 19 and is fastened and fixed by fastening members 22a and 22b. Further, the nozzle adapter 21 has an end portion 21b opposite to the discharge port 19b fixed to a top plate of the substrate receiving portion 12 described later by fastening members 23a and 23b.

  The substrate receiving portion 12 includes a case 24 attached forward from the tip of the flat nozzle 19, a roll brush 25 that holds the glass substrate 14 peeled from the polishing pad 13, and a substrate receiving portion when the glass substrate 14 is peeled from the polishing pad 13. And jig stands 26 a and 26 b for supporting the portion 12.

  The case 24 has a box shape with one surface open, and includes a top plate 24a and side walls 24b that rise vertically from the outer peripheral edge of the top plate 24a. A nozzle adapter 21 is formed on the side wall 24c on the attachment side of the case 24 (on the flat nozzle 19 side). The case 24 is provided so as to cover the glass substrate 14.

  The base end portion of the roll brush 25 is attached to the center portion on the lower surface side of the top plate 24a. The roll brush 25 includes an attachment shaft 25a as a core material, and bristle material provided radially on the outer peripheral surface of the attachment shaft 25a. A screw portion 25b is provided on the upper portion of the mounting shaft 25a. The screw portion 25b penetrates upward from the top plate 24a through a through hole 24d provided in the central portion of the top plate 24a and is fastened by a fastening member 27. Has been. The roll brush 25 is mounted such that the lower end of the mounting shaft 25a is positioned at a predetermined distance in the horizontal direction from the tip of the flat nozzle. The lower end of the mounting shaft 25a of the roll brush 25 is provided so as to slightly protrude from the lower end of the side wall 24b than the thickness of the glass substrate 14.

  The length of the hair of the bristle material and the size of the mounting shaft 25 a are adjusted so that the diameter of the roll brush 25 is larger than the circular hole that is the central opening of the glass substrate 14. The roll brush 25 is inserted into a circular hole at the center of the glass substrate 14 peeled from the polishing pad 13, and is configured to support the circular hole at the center of the glass substrate 14 from the lower surface by the bristles of the roll brush 25. Yes.

  Cylindrical jig stands 26a and 26b are attached to the outer edge on the lower surface side of the top plate 24a. The jig stands 26a and 26b extend vertically downward from the top plate 24a, and are provided so that the lower ends protrude slightly from the thickness of the glass substrate 14 from the lower ends of the side walls 24b. Further, the jig stands 26a and 26b are arranged such that when the lower ends thereof are brought into contact with the polishing pad 13, the lower end of the roll brush 25 is preferably high enough not to enter the circular hole in the center of the glass substrate 14, or More preferably, the position and size are adjusted so as to be the same height as the circular hole in the center of the glass substrate 14. The upper ends of the jig stands 26a and 26b are fastened and fixed by fastening members 28a and 28b.

  Next, a compressed air supply system to the substrate peeling jig 1 will be described with reference to FIG. As shown in FIG. 2, the substrate peeling jig 1 is supplied with compressed air from instrument air in a factory or the like, or a compressed air supply source 28 such as an air compressor. The compressed air supply system to the substrate peeling jig 1 includes, in order from the compressed air supply source 28 side, an air filter 29 that removes dust and the like in the compressed air, an open / close valve 30 that controls the flow rate of the compressed air, and compressed air. A regulator 31 for reducing the primary pressure of the compressed air supplied from the supply source 28 to a predetermined secondary pressure is disposed. In addition to the air filter 29, an oil mist collector or the like that removes oil or moisture in the air may be disposed in the compressed air supply system as necessary. Moreover, as compressed air, you may use various gas from which specific gravity differs in addition to air.

  Next, the peeling operation | movement of the glass substrate 14 using the board | substrate peeling jig 1 is demonstrated with reference to FIG.2, FIG.3 (a), (b). As shown in FIG. 2, first, the supply of compressed air is started with the open / close valve 30 open. The compressed air supplied from the compressed air supply source 28 is dust-removed by the air filter 29, reduced to a secondary pressure that is a predetermined set pressure by the regulator 31, and supplied to the substrate peeling jig 1. The set pressure of the regulator 31 is set to 0.3 MPa, for example.

  As shown in FIG. 3A, in the substrate peeling jig 1, the roll brush 25 is disposed at a position corresponding to the circular hole at the center of the glass substrate 14, and the discharge port 19b of the flat nozzle 19 is the outer peripheral edge of the glass substrate 14. The lower end of the mounting shaft 25a of the roll brush 25 and the lower ends of the jig stands 26a and 26b are brought into contact with the polishing pad 13 so as to be arranged in the vicinity. Since the substrate receiving portion 12 is provided so that the lower end of the mounting shaft 25a of the roll brush 25 and the lower ends of the jig stands 26a and 26b protrude from the lower end of the side wall 24b of the case 24, the lower end of the side wall 24b, the polishing pad 13, and the like. Is provided with a predetermined interval L1. Moreover, the board | substrate receiving part 12 is comprised so that the predetermined space | interval L2 may be provided between the side wall 24b and the glass substrate 14. FIG.

  Next, by gripping the operation lever 18 of the substrate peeling jig 1, the flat nozzle 19 is directed toward the space between the polishing pad 13 and the glass substrate 14 (the space between the polishing pad 13 and the outer peripheral chamfered portion of the glass substrate 14). The compressed air having the secondary pressure set by the regulator 31 is discharged. Stress is applied to the glass substrate 14 from which the compressed air has been discharged, and the glass substrate 14 is peeled off from the polishing pad 13. Here, since the lower end of the mounting shaft 25a of the roll brush 25 is disposed in the vicinity of the circular hole in the central portion of the glass substrate 14, the glass substrate 14 peeled off from the polishing pad 13 as shown in FIG. Then, it floats while being guided by the roll brush 25, and the roll brush 25 is inserted into the circular hole at the center of the glass substrate 14. Further, since the roll brush 25 is adjusted so that the diameter is larger than the inner diameter of the glass substrate 14, the inner wall of the circular hole in the central portion of the glass substrate 14 is lifted while coming into contact with the hair tips of the roll brush 25. In this state, the glass substrate 14 is supported from the lower surface side by the hair tips. For this reason, in the board | substrate receiving part 12, the fall of the glass substrate 14 peeled from the polishing pad 13 can be prevented, and adhesion of the damage | wound to the glass substrate 14 can be suppressed. The compressed air discharged into the case 24 is discharged out of the case 24 through an interval L1 between the lower end of the side wall 24b and the polishing pad 13.

  Finally, the glass substrate 14 held on the substrate receiving portion 12 can be removed by hand, and the glass substrate 14 can be peeled off from the polishing pad 13 without being scratched or soiled. At this time, since the gap L2 is provided between the glass substrate 14 and the side wall 24b, the glass substrate 14 can be easily taken out. In the present embodiment, the glass substrate 14 can be peeled from the polishing pad 13 in a compressed air discharge time of, for example, one second or less.

  In the present embodiment, from the viewpoint of suppressing the drying of the glass substrate 14, it is preferable that the opening degree of the opening / closing valve 30 is slightly open when the glass substrate 14 is peeled off, and the operation lever 18 is gripped to discharge compressed air. More preferably, the valve opening is such that the display pressure value of the regulator 31 is not more than the measurement range in a state where the pressure is kept, specifically 0.05 MPa or less. By adjusting the valve opening in this way, the amount of compressed air discharged from the substrate peeling jig 1 can be made the minimum necessary amount necessary for peeling the glass substrate 14. Further, even when the release of the operation lever 18 is delayed and the stop of the discharge of the compressed air is delayed, the excessive discharge of the compressed air to the glass substrate 14 can be suppressed, and the dirt accompanying the drying of the glass substrate 14 Can be prevented. In addition, as the valve opening degree of the opening / closing valve 30 described above, for example, the flow rate per unit time of the compressed air supplied to the substrate peeling jig 1 via the regulator 31 is per unit time discharged from the substrate peeling jig 1. For example, the valve opening is smaller than the flow rate of the compressed air.

  In the above-described embodiment, the example in which the opening / closing valve 30 is provided on the upstream side of the regulator 31 has been described. However, the arrangement of the opening / closing valve 30 determines the flow rate per unit time of compressed air supplied to the substrate peeling jig. If it can be adjusted, it may be provided on the downstream side of the regulator 31, or may be provided on both the upstream side and the downstream side. Further, in order to measure the flow rate of such compressed air, a flow meter or the like may be provided between the regulator 31 and the substrate peeling jig 1 as necessary.

  Moreover, in this Embodiment, since the glass substrate 14 is peeled from the polishing pad 13 by discharge of compressed air, there is a concern that the glass substrate 14 may be easily dried, but the pressure of the compressed air is controlled as described above. By doing so, drying of the glass substrate 14 can be suppressed, and contamination of the glass substrate 14 and adhesion of foreign matter can be prevented.

  In addition, the magnitude | size of the diameter of the roll brush 25 will not be specifically limited if it is a magnitude | size which can hold | maintain the glass substrate 14 peeled from the polishing pad 13. FIG. Further, the roll brush 25 can be appropriately held even when glass substrates 14 having different sizes and weights are used by combining the diameter of the mounting shaft 25a, the length of the brush hair, and the material of the brush. .

  Moreover, as a bristle material of the roll brush 25, by using the resin hair about 0.2 mm in diameter, a hair tip can be made flexible and the adhesion of the damage | wound to the glass substrate 14 can be suppressed. Further, as a material of the hair material, for example, nylon or the like can be used. Note that the roll brush 25 may be configured to be rotatable from the viewpoint of further reducing the adhesion of scratches to the glass substrate 14. The roll brush 25 is not particularly limited as long as it is a roll member that is inserted into a circular hole in the center of the glass substrate 14 and can support the glass substrate 14 from the lower surface side of the circular hole. A sponge or the like may be used. For example, when a sponge is used, the end face of the circular hole of the glass substrate can be supported.

  In the present embodiment, by making the width of the discharge port 19 b of the flat nozzle 19 equivalent to the diameter of the glass substrate 14, compressed air is discharged over a wide range at the boundary between the glass substrate 14 and the polishing pad 13. In addition, stress can be effectively generated in the glass substrate 14. Further, since the flat nozzle 19 is connected to be inclined with respect to the plane F1 including the rotation direction of the operation lever 18, even in the polishing apparatus shown in FIG. Interference with the panel 41 can be prevented, and operability can be improved.

  Moreover, in this Embodiment, since the case 24 is provided so that the glass substrate 14 may be covered, scattering of the polishing liquid at the time of spraying compressed air can be prevented. The jig stands 26a and 26b are arranged so that a predetermined distance L1 is formed between the lower surface of the case 24 and the polishing pad 13 when the jig stands 26a and 26b are brought into contact with the polishing pad 13. Therefore, the jig stands 26a and 26b are compressed on the glass substrate 14. Excess compressed air protruding into the air can be discharged out of the case 24. Furthermore, by providing the case 24 so that a predetermined distance L2 is formed between the glass substrate 14 and the side wall 24b of the case 24, the glass substrate 14 can be easily taken out from the substrate receiving portion 12. Note that the case 24 may be configured such that the lower end of the case 24 and the polishing pad 13 come into contact with each other as long as excessive compressed air can be discharged.

  As described above, according to the present embodiment, the glass adhering to the polishing pad 13 without contacting the surface of the glass substrate 14 by discharging compressed air between the polishing pad 13 and the glass substrate 14. Since the substrate 14 can be removed, the adhesion of scratches and dirt to the glass substrate 14 can be suppressed.

  In addition, this invention is not limited to the said embodiment, It can implement by changing suitably. The numerical values, materials, sizes, processing procedures, and the like in the above-described embodiment are merely examples, and various modifications can be made within the scope of the effects of the present invention. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  The present invention can be applied to a manufacturing process of a glass substrate for a magnetic disk for a hard disk, a manufacturing process of various semiconductor wafers, and the like.

DESCRIPTION OF SYMBOLS 1 Substrate peeling jig 11 Main body part 12 Substrate receiving part 13 Polishing pad 14 Glass substrate 15 Connection part 16 Open end part 17 Grasping part 18 Operation lever 19 Flat nozzle 19a Connection part 19b Discharge port 20 Connection tool 21 Nozzle adapter 21a Tapered surface 21b End Part 22a, 22b, 23a, 23b, 27, 28a, 28b Fastening member 24 Case 24a Top plate 24b, 24c Side wall 24d Through hole 25 Roll brush 25b Screw part 26a, 26b Jig stand 28 Compressed air supply source 29 Air filter 30 Open / close valve 31 Regulator 41, 42 Polishing surface plate 43 Polishing pad 44 Glass substrate 45 Carrier 46 Sun gear 47 Internal gear 48 Tooth part

Claims (6)

  A main body portion having a through-passage through which compressed air is supplied from one end; a nozzle that is attached to the main body portion so as to be inclined toward the other end of the through-passage and that discharges compressed air; and And a substrate receiving portion for receiving and holding the substrate lifted from the polishing plate by the compressed air discharged from the nozzle and integrated with the main body portion side. The main body includes a grip part in which a part of the through-passage is formed, an opening / closing means provided in the through-passage, and one end part rotatably supported by the grip part for lever rotation operation. And a lever member that opens and closes the opening and closing means, and a connecting member that connects the grip portion and the nozzle,
The substrate receiving portion is inserted into the central opening of the substrate that is lifted from the polishing plate and holds the substrate, and the tip of the roll member at a position that is a predetermined distance in the horizontal direction from the tip of the nozzle 2. The substrate peeling jig for a magnetic disk according to claim 1, further comprising a support member that supports a base end portion of the roll member so that the position of the roll member is positioned.   3. The magnetic disk substrate peeling jig according to claim 2, wherein the roll member is a roll brush.   3. The magnetic disk substrate peeling jig according to claim 2, wherein the roll member is a resin sponge.   5. The substrate peeling jig for a magnetic disk according to claim 1, wherein the nozzle is a flat nozzle whose discharge port has a width corresponding to the outer diameter of the substrate.   A pressure that is provided in a compressed air supply path from the compressed air supply source to the magnetic disk substrate peeling jig according to any one of claims 1 to 5, and converts the primary pressure of the compressed air into a predetermined secondary pressure. A pressure control mechanism comprising: a control unit; and an open / close valve provided on an upstream side of the pressure control unit in the compressed air supply path and configured to limit a supply amount of the compressed air by adjusting a valve opening degree. .

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