JP2010227766A - Washing brush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a washing brush capable of preventing the surface of a glass substrate from being scratched in a washing process of removing abrasives and impurities stuck to the surface of the glass substrate. <P>SOLUTION: The washing brush 1 for washing a body to be washed includes: a brush body 2 in a cylindrical shape rotated around a rotary shaft 4; and a plurality of brush pieces 3 arrayed on the outer peripheral surface of the brush body 2. Each brush piece 3 has a rectangular distal end face 3d comprising a short side 3a and a long side 3b, the short side 3a is a side vertical to the rotary shaft 4, and the long side 3b is a side parallel to the rotary shaft 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cleaning brush for cleaning an object to be cleaned.

  Conventionally, a glass substrate has been used as one of magnetic disk substrates such as HDD devices suitable for increasing the recording density. Since the glass substrate has higher rigidity than the metal substrate, it is suitable for high-speed rotation of the magnetic disk device. Further, since a smooth and flat surface can be obtained, the glass substrate can reduce the flying height of the magnetic head and is suitable for improving the S / N ratio and increasing the recording density.

In general, in the manufacturing process of a glass substrate for a magnetic disk, a polishing process is performed in which the surface of the glass substrate is polished with an abrasive to finish the surface of the glass substrate with high accuracy. In addition, after the polishing process, a cleaning process for removing abrasives, polishing debris, and other impurities attached to the surface of the glass substrate is performed.
It is known that this cleaning process is performed by brushing the surface of the glass substrate with a cleaning brush having protrusions (for example, Patent Documents 1 and 2).

JP 2000-246187 A JP 2008-119621 A

  However, when the surface of the glass substrate is brushed with a cleaning brush having protrusions, as shown in FIG. 6, the pressing pressure of the cleaning brush against the glass substrate exceeds a predetermined value (in the case of FIG. 6, around 400). As a result, there has been a problem that the surface of the glass substrate is easily scratched in an attempt to remove the abrasive and impurities adhering to the surface of the glass substrate.

  The present invention has been made in view of the above points, and for cleaning that can prevent the surface of the glass substrate from being scratched in the cleaning step of removing the abrasive and impurities attached to the surface of the glass substrate. The object is to provide a brush.

  A cleaning brush according to the present invention is a cleaning brush for cleaning an object to be cleaned, and includes a cylindrical brush body that rotates about a rotation axis, and a plurality of brush bodies arranged on the outer peripheral surface of the brush body. Each brush piece has a rectangular tip surface composed of a short side and a long side, the short side is a side perpendicular to the rotation axis, and the long side is It is a side parallel to the rotation axis.

  According to this structure, the front end surface of each brush piece is a rectangle, and the short side of the rectangle is perpendicular to the rotation axis, that is, parallel to the circumferential direction of the brush body. For this reason, the contact surface of each brush piece with respect to the object to be cleaned has a short linear shape with a uniform width in the circumferential direction of the brush body. On such a contact surface, the pressing pressure against the object to be cleaned is distributed substantially uniformly within the contact surface. Therefore, it is possible to prevent the object to be cleaned from being scratched by the pressing pressure applied to the object to be cleaned being concentrated on a part of the contact surface.

  Further, in the cleaning brush, a base end portion of each brush piece is fixed on an outer peripheral surface of the brush body, and the height from the base end portion of the brush piece to the tip end surface is as described above. The ratio of the lengths of the short sides is 0.1 to 0.5.

  According to this configuration, the length of the short side parallel to the circumferential direction of the brush body can be sufficiently shortened relative to the height of the brush piece perpendicular to the circumferential direction. For this reason, the brush piece can be easily bent in the circumferential direction of the brush body.

  In the cleaning brush, each of the brush pieces is a flat plate-shaped rectangular parallelepiped whose cross section has the same shape as the tip surface.

  According to this configuration, since the brush piece is a thin flat plate-like rectangular parallelepiped, the flexibility of the brush piece can be increased as compared with the cylindrical brush piece.

  In the cleaning brush, a ratio of the length of the short side to the length of the long side is 0.05 to 0.2.

  In the cleaning brush, each brush piece is made of a polyvinyl acetal porous material, like the brush body.

  In the cleaning brush, the object to be cleaned is a glass substrate for a magnetic disk.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that the surface of a glass substrate is damaged in the washing | cleaning process which removes the abrasive | polishing agent and impurity which adhered to the surface of the glass substrate.

It is a perspective view of the brush for washing concerning the embodiment of the present invention. It is the schematic diagram which expanded the brush piece of the brush for washing | cleaning which concerns on embodiment of this invention. It is a figure which shows the front end surface of the brush piece which concerns on (a) embodiment of this invention, and the contact surface with respect to the glass substrate of the brush piece which concerns on (b) embodiment of this invention. (A) It is a figure which shows the front end surface of the brush piece which concerns on a comparative example, and the contact surface with respect to the glass substrate of the brush piece which concerns on (b) comparative example. It is a figure which shows the comparison result of the number of defects of the cleaning brush which has the brush piece which concerns on embodiment of this invention, and the cleaning brush which has the brush piece which concerns on a comparative example. It is a figure which shows the number of defects on the glass substrate with respect to the pressing pressure of the conventional brush for washing | cleaning.

  Hereinafter, the configuration of the cleaning brush according to the present embodiment will be described. This cleaning brush is used in the cleaning step of the method for manufacturing a magnetic disk glass substrate, but can also be used for cleaning substrates other than the magnetic disk glass substrate.

  FIG. 1 is a perspective view of a cleaning brush according to an embodiment of the present invention. As shown in FIG. 1, the cleaning brush 1 includes a cylindrical brush body 2, a plurality of brush pieces 3 arranged on the outer peripheral surface of the brush body 2, and a rotating shaft 4 of the brush body 2. The The plurality of brush pieces 3 provided on the outer peripheral surface of the brush body 2 are arranged so as to form a brush piece row parallel to the rotation shaft 4. Such a brush piece row is formed on the entire surface of the brush body 2 in the circumferential direction 2a. Adjacent brush piece rows are alternately arranged so as to fill the gaps between the brush pieces 3.

  FIG. 2 is an enlarged schematic view of the brush piece 3 of the cleaning brush 1. As shown in FIG. 2, the brush piece 3 has a rectangular tip surface 3d composed of a short side 3a and a long side 3b. The short side 3 a is a side perpendicular to the rotation axis 4 of the brush body 2, and the long side 3 b is a side parallel to the rotation axis 4 of the brush body 2. Note that the ratio of the length of the short side 3a to the length of the long side 3b is preferably 0.05 to 0.2.

  Further, the brush piece 3 is a plate-shaped rectangular parallelepiped in which the cross section of the brush piece 3 has the same shape as the tip surface 3d. The base end portion 3 e of the brush piece 3 has the same shape as the distal end surface 3 d and is fixed on the outer peripheral surface of the brush body 2. Here, the ratio of the length of the short side 3a to the height 3c from the base end portion 3e to the tip end surface 3d of the brush piece 3 is desirably 0.1 to 0.5.

  Moreover, the brush piece 3 is comprised from the raw material which shows a softness | flexibility and moderate rebound resilience, for example, a polyvinyl acetal type porous material. The brush body 2 may also be made of a polyvinyl acetal porous material, like the brush piece 3.

  Next, a method for cleaning the glass substrate 5 using the cleaning brush 1 configured as described above will be described using a comparative example.

  Fig.3 (a) is a figure which shows the front end surface 3d of the brush piece 3 which concerns on embodiment of this invention, FIG.3 (b) is the contact with respect to the glass substrate 5 of the brush piece 3 which concerns on embodiment of this invention. It is a figure which shows the surface 3f. FIG. 4A is a view showing the tip surface 6b of the brush piece 6 of the cleaning brush 1 as a comparative example, and FIG. 4B is a glass diagram of the brush piece 6 of the cleaning brush 1 as a comparative example. It is a figure which shows the contact surface 6c with respect to the board | substrate 5. FIG.

  The glass substrate 5 is cleaned by bringing the brush pieces 3 arranged on the outer peripheral surface of the brush body 2 into contact with the cleaning surface 5 a of the glass substrate 5. Specifically, the brush piece 3 has a deformed state (see FIG. 3B) pressed by the glass substrate 5 in the circumferential direction 2a of the brush body 2 and a deformed release state separated from the glass substrate 5 (FIG. 3 ( The cleaning surface 5a of the glass substrate 5 is brushed by frequently repeating step a). By this brushing action, abrasives, polishing debris and other impurities attached to the cleaning surface 5a of the glass substrate 5 are removed.

  Here, in the cleaning brush 1 according to the present embodiment, as shown in FIG. 3A, the tip surface 3 d of the brush piece 3 is rectangular, and the short side 3 a of the rectangle is perpendicular to the rotation axis 4. It is. Here, as shown in FIG. 1, since the rotation shaft 4 is perpendicular to the circumferential direction 2 a of the brush body 2, the short side 3 a is parallel to the circumferential direction 2 a of the brush body 2. For this reason, as shown in FIG.3 (b), the contact surface 3f of the brush piece 3 with respect to the washing | cleaning surface 5a of the glass substrate 5 becomes a short linear shape with the width with respect to the circumferential direction 2a of the brush main body 2 uniform.

  In such a contact surface 3f, the pressing pressure against the cleaning surface 5a is distributed substantially uniformly in the contact surface 3f and does not concentrate on a part of the contact surface 3f. Therefore, the pressing pressure on the cleaning surface 5a is unlikely to exceed a predetermined value, and the probability that the cleaning surface 5a is scratched is reduced.

  On the other hand, in the cleaning brush as a comparative example, as shown in FIG. 4A, the tip surface 6b of the brush piece 6 is circular with a diameter 6a. For this reason, as shown in FIG. 4 (b), the corners of the circumferential portion of the tip surface 6 b of the brush piece 6 gradually deform after the point contact with the cleaning surface 5 a of the glass substrate 5. Therefore, the contact surface 6c of the brush piece 6 with respect to the cleaning surface 5a of the glass substrate 5 has a nonlinear distorted shape.

  In such a contact surface 6c, the pressing pressure with respect to the cleaning surface 5a is concentrated on a portion 6d in the contact surface 6c, that is, a portion 6d in point contact with the cleaning surface 5a. Therefore, the pressing pressure on the cleaning surface 5a in contact with the portion 6d is likely to exceed a predetermined value, and the probability that the cleaning surface 5a in contact with the portion 6d is scratched is increased.

  As described above, in the cleaning brush 1 according to the present embodiment, the contact surface 3f of each brush piece 3 with respect to the cleaning surface 5a of the glass substrate 5 has a short linear shape with a uniform width in the circumferential direction 2a of the brush body 2. It becomes. In such a contact surface 3f, the pressing pressure against the cleaning surface 5a of the glass substrate 5 is distributed substantially uniformly in the contact surface 3f. Accordingly, it is possible to prevent the cleaning surface 5a of the glass substrate 5 from being scratched by the pressing pressure against the cleaning surface 5a of the glass substrate 5 being concentrated on a part of the contact surface.

  Further, in the brush piece 3 of the cleaning brush 1 according to the present embodiment, the length of the short side 3a parallel to the circumferential direction 2a of the brush body 2 is the height 3c in the direction perpendicular to the circumferential direction 2a. Therefore, the brush piece 3 can be easily bent in the circumferential direction 2 a of the brush body 2. Further, since the brush piece 3 is a flat plate-like rectangular body having the same cross section as the tip surface 3d, the flexibility of the brush piece 3 can be enhanced as compared with the cylindrical brush piece 6. Further, since a polyvinyl acetal porous material is used as the material of the brush piece 3, the brush piece 3 has flexibility and moderate rebound resilience.

  As described above, in the cleaning brush 1 according to the present embodiment, the brush piece 3 has flexibility and appropriate rebound resilience depending on the shape and material of the brush piece 3, and thus the brush piece 3 against the cleaning surface 5 a of the glass substrate 5. The pressing pressure is not excessive. Therefore, it is possible to prevent the cleaning surface 5a of the glass substrate 5 from being scratched due to excessive pressing pressure on the cleaning surface 5a of the glass substrate 5.

(Example)
Hereinafter, embodiments of the present invention will be specifically described with reference to examples. In addition, this invention is not limited to a following example.

  (1) Cutting step, (2) Shape processing step, (3) Roughening step, (4) Fine lapping step, (5) End surface polishing step, (6) Main surface polishing step, (7) Chemical strengthening The glass substrate for a magnetic disk of this example was manufactured through the process, (8) cleaning process, and (9) inspection process.

  In addition, the plate-shaped glass raw material for manufacturing the glass substrate for magnetic discs was manufactured by the float process. In the float process, the melt is poured over molten tin and solidified as it is. Since both surfaces of the plate glass were the glass free surface and the glass / tin interface, a plate-like glass material having a mirror surface with a Ra of 0.001 μm or less was obtained without polishing.

(1) Cutting process A plate glass material made of aluminosilicate glass having a thickness of 0.95 mm manufactured by the float method is cut into a square of a predetermined size, and a glass cutter is used on the top surface of the magnetic disk. A circular cut line was formed to describe the substantially peripheral edge on the outer peripheral side and the inner peripheral side of the region to be the glass substrate. As the aluminosilicate _{glass, SiO} 2: 58 wt% to 75 _wt%, Al _{2 O} 3: 5 wt% to 23 wt%, _Li 2 O: 3% to 10% by weight, _Na 2 O: 4 A glass for chemical strengthening containing from 13% by mass to 13% by mass was used. Next, the top surface side of the sheet glass on which the cut line is formed is heated by a heater as a whole, and the cut line is advanced toward the bottom surface side of the plate glass to have a glass substrate 5 (mirror plate glass) having a predetermined diameter. ) Was cut out.

(2) Shape processing step Next, after grinding the outer peripheral end surface and the inner peripheral end surface to an outer diameter of 65 mmφ and an inner diameter (diameter of the circular hole in the central portion) of 20 mmφ, Chamfered. At this time, the surface roughness of the end face of the glass substrate 5 was about 2 μm in Rmax.

(3) Roughening step Using 4.0M HF, a treatment liquid was prepared by adding KOH as a buffering agent. The pH of this treatment liquid was 4.55. The glass substrate 5 was immersed in this processing liquid, and frost processing was performed on the glass surface. The processing temperature for frosting was 50 ° C., and the processing time was 420 seconds. In this frost processing, HF ₂ ⁻ is a corrosion factor and KF acts as a corrosion protection factor. By this frost processing, the entire surface of the specular glass substrate 5 has a substantially uniform surface roughness Ra = 0.01 μm to 0.4 μm. Note that the target surface roughness in the roughening step is desirably determined by the relationship with the particle size of the fixed abrasive used in the subsequent fine lapping step.

(4) Precision lapping process (surface grinding process)
The main surface of the roughened glass substrate 5 was ground using a fixed abrasive polishing pad. A diamond sheet was used as a fixed abrasive polishing pad. The diamond sheet is provided with diamond particles as abrasive grains. The diamond sheet includes a sheet made of PET as a base material. The average particle diameter of the diamond particles was B = 4 μm.

  In the fine lapping process, the roughened glass substrate 5 is set in a lapping apparatus, and the disk surface is lapped with a diamond sheet, so that the surface roughness Ra is 0.1 μm or less at a high processing rate. The degree could be 6 μm or less.

  Thus, since the main surface of the glass substrate 5 is roughened in the roughening step in advance, a convex portion that becomes a catch of fine fixed abrasive grains is formed on the main surface of the glass substrate 5, and fixed abrasive It is possible to prevent the problem that the grains slip on the surface of the material, and the processing rate in the fine lapping process can realize a high processing rate from the start of surface polishing. The processing rate here was 6.0 μm / min.

(5) End face polishing step Next, the surface roughness of the end face (inner circumference, outer circumference) of the glass substrate 5 is about 0.4 μm at Rmax and about 0.1 μm at Ra while rotating the glass substrate 5 by brush polishing. Polished.

(6) Main surface polishing step Next, a first polishing step for removing scratches and distortions remaining in the lapping step described above was performed using a double-side polishing apparatus. In the double-side polishing apparatus, the glass substrate 5 held by the carrier is closely attached between the upper and lower polishing surface plates to which the polishing pad is attached, the carrier is meshed with the sun gear and the internal gear, and the glass substrate 5 is attached. Clamp with upper and lower polishing surface plate. Thereafter, by supplying and rotating a polishing liquid between the polishing pad and the polishing surface of the glass substrate 5, the glass substrate 5 revolves while rotating on the polishing surface plate to simultaneously polish both surfaces. . Specifically, a hard polisher (hard foamed urethane) was used as the polisher, and the first polishing step was performed.

  Next, using the same double-side polishing apparatus as that used in the first polishing step, the second polishing step was performed by replacing the polisher with a polishing pad of soft polisher (suede). In this second polishing step, for example, the surface roughness of the main surface of the glass substrate 5 is finished to a smooth mirror surface having an Rmax of about 3 nm or less while maintaining the flat surface obtained in the first polishing step. Mirror polishing process.

(7) Chemical Strengthening Step Next, the glass substrate 5 was chemically strengthened. Ion exchange is performed to ions (Na ⁺ and K ⁺ ) having a larger ion radius than ions existing on the surface of the glass substrate 5 (for example, Li ⁺ and Na ⁺ when using an aluminosilicate glass). On the surface of the glass substrate 5 (for example, from the surface of the glass substrate 5 to about 5 μm), ions are exchanged with atoms having a large ion radius, and the compression stress is applied to the glass surface to increase the rigidity of the glass substrate 5. . In this way, a glass substrate for a magnetic disk of this example was obtained.

(8) Cleaning Step In order to remove the abrasive, polishing debris, and impurities adhering to the surface of the glass substrate 5, scrub cleaning was performed using the cleaning brush 1 having the plate-like brush piece 3. The cleaning time for scrub cleaning was 10 seconds, and the rotation speed of the cleaning brush 1 was 300 rpm. In addition, a polyvinyl acetal porous material was used as the material for the flat brush piece 3.

  In this embodiment, the cleaning process is described after the chemical strengthening process for the sake of convenience. However, the cleaning process is also performed between each process from the fine lapping process (surface grinding process) to the first polishing process and the second polishing process. As appropriate.

(9) Inspection process About both main surfaces of the glass substrate 5, it was test | inspected whether the specification for forming a recording surface was satisfied. Specifically, both main surfaces of the chemically strengthened glass substrate 5 are cleaned using the cleaning brush 1 having the flat-plate-shaped brush pieces 3, and then scratches and dirt on the surface of the glass substrate 5 ( Defects such as particles), material factors and shape changes were inspected. As a result, as shown in FIG. 5, the number of defects on the surface of the glass substrate 5 in the case of using the cleaning brush 1 having the plate-like brush piece 3 was 38.

(Comparative example)
In the comparative example, the cleaning process was performed using the cleaning brush 1 having the cylindrical brush piece 6 instead of the cleaning brush 1 having the flat brush piece 3. The cleaning time for scrub cleaning was 10 seconds, and the rotation speed of the cleaning brush 1 was 300 rpm. A polyvinyl acetal porous material was used as the material of the cylindrical brush piece 6.

  After such a cleaning process, an inspection process was performed. The conditions for each step other than those described above were the same as in the examples. As a result, as shown in FIG. 5, the number of defects on the surface of the glass substrate 5 when the cleaning brush 1 having the cylindrical brush piece 6 was used was 54.

  As described above, the number of defects on the surface of the glass substrate 5 as a result of the inspection process in the example and the comparative example is as follows. As shown in FIG. When it was “38”, it was “54” when the surface of the glass substrate 5 was cleaned using the cylindrical brush piece 6.

  That is, by performing the cleaning process using the cleaning brush 1 having the flat-shaped brush piece 3, the surface of the glass substrate can be prevented from being scratched, and thus the cylindrical brush piece 6 is provided. Compared with the case where the cleaning process was performed using the cleaning brush 1, the number of defects on the surface of the glass substrate 5 could be reduced.

  The present invention is not limited to the above embodiment and can be implemented with various modifications. For example, the material, the number, the size, the processing procedure, and the like in the above-described embodiment are examples, and various changes can be made within the range where the effects of the present invention are exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Brush 2 ... Brush body 3 ... Brush piece (flat plate shape)
3a ... short side 3b ... long side 3c ... height 3d ... tip surface 3e ... base end surface 3f ... contact surface 4 ... rotating shaft 5 ... glass substrate 5a ... cleaning surface 6 ... brush piece (cylindrical shape)
6a ... diameter 6b ... tip surface 6c ... contact surface 6d ... part of contact surface

Claims (6)

A cleaning brush for cleaning an object to be cleaned,
A cylindrical brush body that rotates about a rotation axis;
A plurality of brush pieces arranged on the outer peripheral surface of the brush body,
Each brush piece has a rectangular tip surface composed of a short side and a long side,
The short side is a side perpendicular to the rotation axis,
The cleaning brush according to claim 1, wherein the long side is a side parallel to the rotation axis. The base end portion of each brush piece is fixed on the outer peripheral surface of the brush body,
The ratio of the length of the said short side with respect to the height from the said base end part of the said brush piece to the said front end surface is 0.1-0.5, For washing | cleaning of Claim 1 characterized by the above-mentioned. brush.   The brush for cleaning according to claim 1, wherein each brush piece is a flat plate-shaped rectangular parallelepiped having a cross section identical to the tip surface.   The cleaning brush according to any one of claims 1 to 3, wherein a ratio of the length of the short side to the length of the long side is 0.05 to 0.2.   Each said brush piece is comprised from a polyvinyl acetal type porous material, The brush for washing | cleaning in any one of the Claims 1 thru | or 4 characterized by the above-mentioned. 6. The cleaning brush according to claim 1, wherein the object to be cleaned is a glass substrate for a magnetic disk.

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