US20080276394A1

US20080276394A1 - Scrubbing device and roll sponge assembly used therein

Info

Publication number: US20080276394A1
Application number: US12/073,289
Authority: US
Inventors: Narumi Sato
Original assignee: Fuji Electric Device Technology Co Ltd
Current assignee: Fuji Electric Co Ltd
Priority date: 2007-05-08
Filing date: 2008-03-04
Publication date: 2008-11-13
Also published as: JP2008282865A

Abstract

A roll sponge assembly for a scrubbing device includes a support having a support portion and a rotary shaft provided on two ends of the support portion, and a roll sponge having a hollow hole for holding the support by fitting the support portion of the support into the hollow hole. An outer diameter of the roll sponge assembly continuously or in stages increases in a lengthwise direction thereof.

Description

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

The present invention relates to a scrubbing device for cleaning a circular or a rectangular plate such as a magnetic disc substrate made of metal, glass or the like, a semiconductor wafer, and so on, and a roll sponge assembly used in the scrubbing device.
In recent years, magnetic disk drives have become smaller in size and expanded their range of applications, while it has been always demanded to further increase a recording density of a magnetic disc installed in the drive. A magnetic disk is manufactured by forming thin films such as a magnetic layer on a substrate made of glass or a metal such as aluminum. With regard to this type of magnetic disk, major progress has been made, in response to the demands described above, for the development of a substrate capable of reducing the distance (magnetic spacing) between a magnetic head and the magnetic disk. As disclosed in Patent Document 1: Japanese Unexamined Patent Application Publication No. H10-241144 (corresponding U.S. patents: U.S. Pat. No. 6,277,465, U.S. Pat. No. 6,503,600, and U.S. Pat. No. 6,877,343), for example, the surface of the substrate is subjected to precision polishing using fine polishing grains until a super-smooth substrate with a surface roughness Ra of 0.3 nm or less is obtained.
However, when particles are adhered to the substrate, a high degree of smoothness cannot be obtained regardless of the precision with which the substrate is polished, and therefore the cleaning method employed after the precision polishing is extremely important. As a demand for a high degree of smoothness increases, the size of the polishing grains used for the precision polishing has become smaller, so that even large grains are no larger than approximately 1 μm, while small grains are in a range of several tens of nanometers. Therefore, with respect to the required level of the cleanness and the size of the particles, it is extremely difficult to maintain a high level of cleaning quality at all the time.
Ultrasonic cleaning and scrubbing are known as typical methods for cleaning a substrate following precision polishing. As disclosed in Japanese Unexamined Patent Application Publication No. 2002-74653, with ultrasonic cleaning alone, comparatively large polishing agent residue can be removed, but it is still difficult to reliably remove minute residue such as those described above, and therefore a plurality of cleaning tanks is necessary, thereby increasing the cleaning time which adversely affects productivity. On the other hand, as to the scrubbing, as shown in FIGS. 1A and 1B, a roll sponge 3 is capable of removing particles by physically wiping the surface of a substrate 1, and therefore, when a large amount of particles are adhered to the substrate 1, the particles can be removed all at once to a certain extent, making scrubbing more effective than ultrasonic cleaning, which requires a plurality of cleaning tanks as noted above. As the most recent method, a combination of these two cleaning methods is used, as disclosed in Japanese Unexamined Patent Application Publication 2002-74653, to ensure that substrate cleaning be more efficient.
However, the scrubbing method described above has three problems, as follows:
(1) It is difficult to optimize the pressing force of the sponge against the substrate.
(2) When particles accumulate on the sponge, the substrate becomes recontaminated by the particles.
(3) A device for performing multi-stage scrubbing and overcoming problems (1) and (2) is large.
Problem (1) is due to the fact that particles of various materials and sizes become adhered to the cleaning target substrate. As described in Patent Document 2: Japanese Unexamined Patent Application Publication 2002-74653, in the precision polishing process, the material and size of the grains are varied in accordance with the required degree of smoothness, and therefore, the adhesive force between the substrate material and the grains, or in other words, the difficulty of removing the grains from the substrate, differs in each case. Furthermore, debris generated by substrate shavings and polishing pad shavings during polishing, dust produced by a device driving portion, and the like also become adhered to the substrate. Therefore, the type, size and shape of the particles adhered to the substrate vary widely.
In order to improve the cleaning force during scrubbing, an attempt to increase the force to press the roll sponge against the substrate has been conducted. As shown in FIG. 1C, however, depending on the shape and material of the adhered particles, the particles may damage the substrate 1 when wiped away by the sponge if the pressing force of the roll sponge 3 against the substrate 1 is increased. In other words, the likelihood of a defective substrate 1 is extremely high, as shown in FIG. 5A.
As regards problem (2), during the course of scrubbing, a roll sponge attached to a device processes a large amount of substrates, and therefore particles gradually accumulate on the roll sponge. As the particles accumulate, the particles return back to the substrate. As a result, a predetermined level of cleaning quality can no longer be obtained. Furthermore, as noted above in relation to problem (1), particles of various sizes, shapes and materials become trapped on the roll sponge, and therefore, depending on the trapped particles, defects such as scratches are caused continuously on the surface of subsequently processed substrates, thereby undermining the cleaning quality.
Regarding problem (3), multi-stage scrubbing has been tested in consideration of problems (1) and (2). However, since a series of devices, each comprising a driving portion, is required, such a device occupies a large amount of space and is not easy to maintain. Hence, there is a strong demand for measures to clean more efficiently.
An object of the present invention is to provide a scrubbing device and a roll sponge used therein that can solve the problems (1) to (3) described above.
Further objects and advantages of the invention will be apparent from the following description of the invention.

SUMMARY OF THE INVENTION

To achieve the object, a roll sponge assembly for a scrubbing device according to the present invention comprises a support in which a support portion for holding a roll sponge and a rotary shaft provided on either side of the support portion are formed integrally, and a roll sponge that is held on the support by fitting the support portion of the support into a hollow hole of the roll sponge. The roll sponge assembly is formed so that the outer diameter thereof varies in a lengthwise direction.
Due to the shape described above, the support portion of the roll sponge assembly is formed so that the outer diameter thereof gradually and continuously increases in a lengthwise direction, while the roll sponge held on the support is formed so that the outer diameter thereof and the inner diameter of the hollow hole thereof vary continuously in accordance with the change of the outer diameter of the support portion.
Alternatively, the roll sponge assembly for a scrubbing device according to the present invention may be formed so that the outer diameter of the roll sponge held on the support and the inner diameter of the hollow hole are constant, for example.
Further, the roll sponge assembly for a scrubbing device according to the present invention comprises a support in which a support portion for holding a plurality of roll sponges and a rotary shaft provided on either side of the support portion are formed integrally, and a plurality of roll sponges that is held on the support by fitting the support portion of the support into a hollow hole in the plurality of roll sponges. The outer diameter of the support portion of the support in this roll sponge assembly may vary so as to increase in stages in a lengthwise direction, and the plurality of roll sponges may be formed so that the respective outer diameters thereof and the inner diameter of the hollow hole correspond to the plurality of outer diameters of the support portion which vary in stages, so that the respective outer diameters and the inner diameter of the hollow hole are constant in the lengthwise direction.
Further, the scrubbing device according to the present invention comprises at least a plurality of rollers that vertically supports and rotates a cleaning subject, and a pair of roll sponge assemblies disposed horizontally and parallel to each other. The scrubbing device cleans the cleaning subject by moving the cleaning subject in a lengthwise direction between the rotating pair of roll sponge assemblies.
Further, a scrubbing method according to the present invention comprises at least the steps of: rotating a cleaning subject while supporting the cleaning subject vertically using a plurality of rollers; rotating a pair of roll sponge assemblies disposed horizontally and parallel to each other; and moving the cleaning subject rotated by the plurality of rollers between the rotating pair of roll sponge assemblies in a lengthwise direction of the roll sponge assemblies.
In the present invention, the pressing force of the roll sponge in the roll sponge assembly of the scrubbing device against a cleaning substrate can be varied continuously in accordance with the movement of the substrate by varying the outer diameter of the roll sponge. In other words, by moving the cleaning substrate in the lengthwise direction of the roll sponge as scrubbing process goes on, a pressing force corresponding to the cleaning stage can be provided between the roll sponges. Furthermore, in the present invention, the substrate is moved in the lengthwise direction, and therefore different parts of the roll sponge can be continuously used in accordance with the each cleaning stage.
Moreover, in the present invention, only the outer diameter of the roll sponge for the scrubbing device needs to be varied. Therefore highly effective scrubbing corresponding to the cleaning stage can be provided during substrate cleaning without making the device further complicated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B, 1C show a conventional scrubbing device during the course of operation, wherein FIG. 1A is a schematic vertical sectional view of the main parts of the scrubbing device, FIG. 1B is a schematic horizontal sectional view of the main parts of a substrate at the beginning of cleaning and the scrubbing device shown in FIG. 1A, and FIG. 1C is a schematic horizontal sectional view of the main parts of the substrate during cleaning and the same scrubbing device as that shown in FIG. 1B with an increased substrate pressing force.

FIGS. 2A, 2B show a scrubbing device according to an embodiment of the present invention during the course of operations, wherein FIG. 2A is a schematic horizontal sectional view of the main parts of the scrubbing device, and FIG. 2B is a side view of the main parts of the scrubbing device shown in FIG. 2A.

FIGS. 3A, 3B, 3C are views illustrating a substrate cleaning process performed by the scrubbing device shown in FIGS. 2A, 2B, wherein FIG. 3A is a state immediately before the start of substrate cleaning, FIG. 3B is a state at an initial stage of substrate cleaning, and FIG. 3C is a state at the completion of cleaning.

FIGS. 4A, 4B, 4C are views illustrating a substrate cleaning process performed by a pattern-form scrubbing device according to another embodiment of the present invention, wherein FIG. 4A is a state immediately before the start of substrate cleaning, FIG. 4B is a state at the initial stage of substrate cleaning, and FIG. 4C is a state at the completion of cleaning.

FIGS. 5A, 5B are views showing the results of a comparison of the cleaning effects of the present invention and a conventional device.

FIGS. 6A, 6B, 6C show examples of a roll sponge assembly used in the scrubbing device according to the present invention, shown in FIGS. 2A, 2B and 3A, 3B, 3C, wherein FIG. 6A is an exploded view of a roll sponge assembly according to the first embodiment, FIG. 6B is an exploded view of a roll sponge assembly according to a second embodiment, and FIG. 6C is an exploded view of a roll sponge assembly according to a third embodiment.

FIGS. 7A, 7B, 7C, 7D, 7E show examples of a roll sponge assembly used in the scrubbing device according to the present invention shown in FIGS. 4A, 4B, 4C, wherein FIG. 7A is an exploded view of a roll sponge assembly according to a fourth embodiment, FIG. 7B is an exploded view of a roll sponge assembly according to a fifth embodiment, FIG. 7C is an exploded view of a roll sponge assembly according to a sixth embodiment, FIG. 7D is an exploded view of a roll sponge assembly according to a seventh embodiment, and FIG. 7E is an exploded view of a roll sponge assembly according to an eighth embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described with reference to the attached drawings.

First Embodiment

FIGS. 2A and 2B show schematic views of a scrubbing device according to a first embodiment of the present invention. FIGS. 3A to 3C show a substrate cleaning process performed by the scrubbing device. FIGS. 5A and 5B are views comparing the cleaning effects of the first embodiment and a conventional device. FIG. 6A is an exploded view of a roll sponge assembly used in the scrubbing device.
The scrubbing device of this embodiment basically comprises a plurality of rollers 202 for supporting and rotating a cleaning subject 1, and a pair of roll sponge assemblies 201 for cleaning the cleaning subject 1.
In the scrubbing device according to this embodiment, the cleaning subject 1 is an annular magnetic disk substrate. As is evident from FIG. 2B, the cleaning subject substrate 1 is supported vertically in a plurality of (three in this embodiment) support points around its peripheral edge by the plurality of (three in this embodiment) rollers 202. As shown in FIG. 2B, when three rollers 202 are provided, as in this embodiment, two of rollers 202 are preferably disposed horizontally on a lower side of the substrate 1 and the other one of rollers 202 is preferably disposed on a vertical bisector of a line linking the support points of the two horizontally disposed rollers 202 such that the support point intersects the peripheral edge of the substrate 1. Ideally, the three rollers 202 of this embodiment are disposed around the peripheral edge of the substrate 1 so that the respective support points thereof form an equilateral triangle.
Of the plurality of rollers 202, at least one performs rotational driving such that the driving force thereof rotates the substrate 1 via the support point. The other rollers 202 are rotated by the driving roller 202, thereby assisting the rotation of the substrate 1 while supporting the substrate 1 vertically. The plurality of rollers 202 are supported by a shaft, an arm, or the like (not shown in the drawing) and are constituted to be capable of moving while gripping and rotating the substrate 1 in a lengthwise direction of a roll sponge 203 (the direction of an arrow 205) such that relative positional relationships between the rollers remain unchanged. Note that the method of supporting or conveying the substrate 1 may be subjected to various modifications according to the structure of the substrate and the device construction, and is not limited to the method of this embodiment.
In this embodiment, as shown in FIG. 6A, the roll sponge assembly 201 includes the roll sponge 203 for cleaning the substrate 1, and a support 204 that serves as a rotary shaft for supporting and rotating the roll sponge 203.
As shown in FIG. 2B, an outside contour of the roll sponge 203 according to this embodiment takes a conical trapezoid shape having an outer diameter that gradually increases from D₂to D₁(D₁>D₂) in the movement direction (the direction of the arrow 205) of the substrate 1. A conical trapezoid-shaped hollow hole 203 c having an inner diameter that gradually increases from D₃to D₄(D₄>D₃) in the movement direction of the substrate 1, similarly to the outer diameter, is formed at a central portion of the roll sponge 203 in a lengthwise direction (the direction of the arrow 205). The hollow hole 203 c is formed concentrically with the outside contour. Furthermore, in this embodiment, the roll sponge 203 is formed such that (D1-D4)=(D2-D3), or in other words such that the thickness of the roll sponge 203 is constant in the lengthwise direction (the direction of the arrow 205). However, the roll sponge 203 does not have to be limited to this thickness. Further, the roll sponge 203 is preferably made of polyvinyl acetal (PVA) resin, as disclosed in Japanese Unexamined Patent Application Publication No. 2000-246187 and Japanese Unexamined Patent Application Publication No. 2000-312863. PVA resin softens when moist, has superior water absorbing and water holding properties, exhibits flexibility and impact resilience, and is also highly durable.
The support 204 includes a support portion 204 b and a rotary shaft 204 a disposed at either end of the support portion 204 b.
The support portion 204 b has a substantially identical shape to the shape of the hollow hole 203 c in the roll sponge 203. In other words, the support portion 204 b takes a conical trapezoid shape having an outer diameter that gradually increases from D₃to D₄in the right-left direction of FIG. 6A (the direction of the arrow 205 in FIG. 2A). The length of the support portion 204 b in the lengthwise direction (the direction of the arrow 205 in FIG. 2A) is preferably identical to the length of the roll sponge 203, albeit not limited thereto. The support portion 204 b is fitted into the hollow hole 203 c in the roll sponge 203 so as to fix and hold the roll sponge 203.
In this embodiment, as shown in FIG. 6A, the rotary shaft 204 a has the same outer diameter as the minimum outer diameter D₃of the support portion 204 b, and is formed coaxially with the support portion 204 b and integrally with the two ends of the support portion 204 b. At least one of the rotary shafts 204 a disposed on either side of the support portion 204 b is linked to a rotary driving portion (not shown in the drawing) and by means of this mechanism, the roll sponge assembly 201 can be driven to rotate. Note that the outer diameter of the rotary shaft 204 a need not be identical to the minimum outer diameter D₃of the support portion 204 b, as in this embodiment, and may be smaller than the minimum outer diameter D₃, for example.
As shown in FIG. 2A, the scrubbing device of this embodiment is disposed such that a pair of roll sponge assemblies 201, 201 sandwiches the two surfaces of the substrate 1. Furthermore, in this embodiment, the pair of roll sponge assemblies 201, 201 are disposed such that central axes of the respective supports 204, 204 thereof are parallel to each other at a predetermined gap that is smaller than the maximum outer diameter (D₁) of the roll sponge 203. Note that the gap between the supports 204, 204 is not limited to this, and is set appropriately in accordance with various conditions such as the thickness of the substrate and the required cleaning performance. Further, the scrubbing device is disposed such that the rotary axis of the roll sponge assembly 201 and the rotary axis of the roller 202 that vertically supports the substrate 1 form a right angle when seen from above.
As described above, the cleaning subject substrate 1 moves from the right side to the left side of FIG. 2A between the pair of rotating roll sponge assemblies 201, 201 while being rotated by the rollers 202. The movement speed of the substrate 1 is controlled appropriately in accordance with the shape, size and so on of the substrate 1.
An operation for cleaning the substrate 1 using the scrubbing device having the construction described above, and the effects thereof, will now be described using FIGS. 3A to 3C and FIGS. 5A, 5B.
As shown in FIG. 3A, particles of various shapes, sizes and materials are adhered to the surface of the substrate 1 prior to cleaning. In this state, the substrate 1 is inserted between the pair of roll sponge assemblies 201, 201, whereupon scrubbing begins.
As shown in FIG. 3B, in an initial cleaning stage, the outer diameter of the opposing roll sponges 203, 203 is small, and therefore the contact pressure (pressing force) of the roll sponges 203, 203 against the two surfaces of the substrate 1 is small. Accordingly, particles which are lightly adhered to the surface of the substrate 1 and large particles which can be trapped in the roll sponge 203 easily even with a weak pressing force are removed from the substrate 1. Furthermore, since the pressing force is small, the trapped particles fall off the roll sponge 203 easily. Therefore the particles fall away easily due to the centrifugal force and so on from the rotating roll sponge 203. As a result, no substantial particles remain adhered to the roll sponge 203.
Next, as shown in FIG. 3C, the substrate 1 is moved to the side of the roll sponge 203 having a large outer diameter, indicated by the arrow 205. As the outer diameter of the roll sponge 203 increases, the pressing force of the roll sponges 203, 203 against the two surfaces of the substrate 1 increases. As a result, the substrate 1 is scrubbed more forcefully. The particles of a size and an adhesive force corresponding to the pressing force of the roll sponge 203 are removed sequentially, and therefore large particles do not cause scratches and other damage on the surface of the substrate 1 even when the pressing force increases, as shown in FIG. 5B. In addition, an effective cleaning force can be obtained for removing small particles which could not be removed in the previous stage. Moreover, as the outer diameter of the roll sponge 203 increases, centrifugal force on the outer peripheral surface of the roll sponge 203 increases, thereby ensuring that small particles adhered to the surface of the roll sponge 203 fall off the roll sponge 203.
Further, since the part of the roll sponge 203 used varies in the lengthwise direction in accordance with the degree of particles on the substrate 1, the accumulation of particles on the roll sponge 203 is dispersed in comparison with the related art, extending the maintenance lifespan of the roll sponge 203. Also, recontamination and the reoccurrence of damage such as scratches on the substrate 1 can be avoided in comparison with the related art, wherein only particular parts are used continuously.
Further, the roll sponge assembly 201 need only be provided in a pair, and therefore the rotary driving portions of the device need only correspond thereto, improving the maintainability of the device. Furthermore, there is no need for a multi-stage device including a plurality of units, as in the related art, and therefore identical effects to those of a multi-stage device can be obtained in a smaller space.

Second Embodiment

FIG. 6B is an exploded view of a roll sponge assembly employed in a scrubbing device according to a second embodiment of the present invention.
This embodiment basically conforms to the first embodiment described above, but in consideration of the productivity of the expendable roll sponge 203, measures have been taken to adopt a conventional production method in which a constant-diameter roll sponge is simply cut for use. In other words, this embodiment differs from the first embodiment only in the structure of the roll sponge, and all other constitutions are completely identical to the first embodiment.
In this embodiment, as shown in FIG. 6B, a roll sponge assembly 401 includes a roll sponge 403 for cleaning a substrate and a support 404 for supporting the roll sponge 403.
The outer diameter of the outside contour of the roll sponge 403 according to this embodiment is constant in the lengthwise direction and equal to the minimum outer diameter D₂of the roll sponge 203 according to the first embodiment. The inner diameter of a hollow hole 403 c thereof is also constant in the lengthwise direction, and equal to the minimum inner diameter D₃of the hollow hole 203 c in the roll sponge 203 of the first embodiment. Accordingly the thickness of the roll sponge 403 is also constant in the lengthwise direction.
Hence, the roll sponge 403 is formed as a hollow cylindrical body with a constant outer diameter and a constant inner diameter in the lengthwise direction, and therefore mass production is possible, enabling a reduction in the manufacturing cost of the scrubbing device in consideration of the fact that the roll sponge 403 is an expendable component of the scrubbing device.
The support 404 of this embodiment has an identical shape to its counterpart in the first embodiment, and includes a support portion 404 b and a rotary shaft 404 a disposed at either end of the support portion 404 b.
The support portion 404 b has a solid conical trapezoid shape having an outer diameter that increases gradually from D₃to D₄in the right-left direction of FIG. 6B. The length of the support portion 404 b in the lengthwise direction is preferably substantially identical to the length of the roll sponge 403, albeit not limited thereto. The support portion 404 b is fitted into the hollow hole 403 c in the roll sponge 403 so as to fix and hold the roll sponge 403.
In this embodiment, when the support portion 404 b is fitted into the hollow hole 403 c of the roll sponge 403, the flexibility of the roll sponge 403 causes the outside contour of the roll sponge 403 to imitate the outside contour of the support portion 404 b and take the form of a conical trapezoid having a gradually increasing outer diameter. As a result, the roll sponge assembly 401 according to this embodiment has a substantially identical shape to the roll sponge assembly 201 (see FIG. 2B) of the first embodiment.
Hence, when the roll sponge assembly 401 of this embodiment is applied to a scrubbing device, completely identical actions and effects to those of the first embodiment can be obtained during the substrate cleaning.

Third Embodiment

FIG. 6C is an exploded view of a roll sponge assembly employed in a scrubbing device according to a third embodiment of the present invention.
This embodiment also conforms to the first embodiment described above, but improves the shape of the roll sponge and the support for fixing and supporting the roll sponge. Therefore, this embodiment differs from the first embodiment only in the structure of the roll sponge assembly, and is completely identical to the first embodiment in all other constitutions.
In this embodiment, as shown in FIG. 6C, a roll sponge assembly 501 includes a roll sponge 503 for cleaning a substrate and a support 504 for supporting the roll sponge 503.
Similarly to the roll sponge 203 of the first embodiment, the outside contour of the roll sponge 503 according to this embodiment has a conical trapezoid shape having an outer diameter that gradually increases from D₂to D₁in a right-left direction. A hollow hole 503 c is formed in a central portion of the roll sponge 503. In contrast to the roll sponge 203 of the first embodiment, the inner diameter of the hollow hole 503 c is constant in the lengthwise direction and equal to the minimum inner diameter D₃of the hollow hole 203 c in the roll sponge 203 of the first embodiment. Therefore, the thickness of the roll sponge 503 gradually increases from right to left.
As described above, the roll sponge 503 of this embodiment is formed as a hollow cylindrical body having a constant inner diameter in the lengthwise direction, and is therefore easier to manufacture than the roll sponge 203 of the first embodiment, enabling a reduction in the manufacturing cost of the scrubbing device.
The support 504 according to this embodiment supports the roll sponge 503 and also functions as a rotary shaft of the roll sponge assembly 501. As shown in FIG. 6C, the support 504 is formed as a solid cylindrical body (column) having a constant outer diameter in the lengthwise direction, and has a substantially identical outer diameter D3 to the inner diameter of the roll sponge 503. The length of the support 504 is set to be greater than the length of the roll sponge 503 by the length thereof that is used as the rotary shaft. As shown in the drawing, the support 504 of this embodiment has a simple columnar structure, and is therefore easy to manufacture. Note that in this embodiment, the roll sponge support portion and rotary shaft of the support 504 are formed with an identical diameter, but the diameters thereof may be different if necessary.
The support 504 is fitted into the hollow hole 503 c of the roll sponge 503 so as to fix and hold the roll sponge 503. Further, the part of the support 504 that penetrates the roll sponge 503 and projects from either end serves as a rotary shaft. As a result, the roll sponge assembly 501 according to this embodiment has a substantially identical shape to the roll sponge assembly 201 (see FIG. 2B) of the first embodiment.
Hence, when the roll sponge assembly 501 of this embodiment is applied to a scrubbing device, identical actions and effects to those of the first embodiment can be obtained when cleaning the substrate 1.

Fourth Embodiment

FIGS. 4A to 4C show a scrubbing device according to a fourth embodiment of the present invention, and FIG. 7A is an exploded view of a roll sponge assembly employed therein.
This embodiment basically conforms to the first embodiment described above, but similarly to the second embodiment, measures have been taken in consideration of the productivity of the expendable roll sponge to adopt a conventional production method in which a constant-diameter roll sponge is simply cut for use. In other words, this embodiment essentially differs from the first embodiment only in the structure of the roll sponge assembly, and all other structures are absolutely identical to the first embodiment. Therefore, there are no substantial differences in the effects exhibited thereby.
In this embodiment, as shown in FIG. 7A, a roll sponge assembly 301 includes a roll sponge 303 comprising two roll sponges 303 a, 303 b for cleaning the substrate 1, and a support 304 for supporting the two roll sponges 303 a, 303 b. In this embodiment, as shown in FIG. 7A, the roll sponge assembly 301 is structured such that the outer diameter of an outside contour thereof varies in stages.
The outer diameter of the outside contour of a small diameter roll sponge 303 a according to this embodiment is constant in the lengthwise direction and equal to the minimum outer diameter D₂of the roll sponge 203 according to the first embodiment. The inner diameter of a hollow hole 303 c is also constant in the lengthwise direction, and identical to the minimum inner diameter D₃of the hollow hole 203 c in the roll sponge 203 according to the first embodiment. Therefore, the thickness of the small diameter roll sponge 303 a is also constant in the lengthwise direction. Meanwhile, the outer diameter of the outside contour of a large diameter roll sponge 303 b is constant in the lengthwise direction, similarly to the small diameter roll sponge 303 a described above, but equal to the maximum outer diameter D₁of the roll sponge 203 according to the first embodiment. The inner diameter of a hollow hole 303 d in the large diameter roll sponge 303 b is constant in the lengthwise direction, similarly to the outer diameter of the outside contour, and equal to the maximum inner diameter D₄of the roll sponge 203 according to the first embodiment.
Hence, the roll sponge 303 is formed as a hollow cylindrical body having a constant outer diameter and a constant inner diameter in the lengthwise direction, and therefore mass production is possible, enabling a reduction in the manufacturing cost of the scrubbing device in consideration of the fact that the roll sponge 303 is an expendable component of the scrubbing device.
As shown in FIG. 7A, a support 304 of this embodiment includes, from left to right, a rotary shaft 304 a, a first support portion 304 b, and a second support portion 304 c.
As shown in FIG. 7A, the rotary shaft 304 a is formed as a solid cylindrical body having a constant outer diameter in the lengthwise direction (the direction of an arrow 205 in FIG. 4A). The rotary shaft 304 a has an identical outer diameter D₃to the outer diameter of the second support portion 304 c to be described above, and is disposed coaxially with the first support portion 304 b. The rotary shaft 304 a is linked to a rotary driving portion (not shown in the drawing), and by means of this mechanism, in association with the second support portion 304 c, the roll sponge assembly 301 can be driven to rotate.
The first support portion 304 b is formed as a solid cylindrical body having a constant outer diameter in the lengthwise direction, and has a substantially identical outer diameter D₄to the inner diameter of the hollow hole 303 d in the large diameter roll sponge 303 b. The length of the first support portion 304 b in the lengthwise direction is preferably identical to the length of the large diameter roll sponge 303 b, albeit not limited thereto. The first support portion 304 b is fitted into the hollow hole 303 d in the large diameter roll sponge 303 b so as to fix and hold the large diameter roll sponge 303 b.
The second support portion 304 c supports the small diameter roll sponge 303 a and also functions as a rotary shaft of the roll sponge assembly 301. As shown in FIG. 7A, the second support portion 304 c is formed as a solid cylindrical body having a constant outer diameter in the lengthwise direction, and has a substantially identical outer diameter D3 to the inner diameter of the small diameter roll sponge 303 a. In consideration of the fact that the second support portion 304 c also functions as a rotary shaft, the length of the second support portion 304 c in the lengthwise direction is set to be greater than the length of the small diameter roll sponge 303 a by the length thereof that is used as the rotary shaft (the same length as the rotary shaft 304 a). The second support portion 304 c is fitted into the hollow hole 303 c in the small diameter roll sponge 303 a so as to fix and hold the roll sponge 303 a. Further, the right side part of the second support portion 304 c that penetrates the roll sponge 303 a and projects therefrom is used as the rotary shaft. Note that the large diameter roll sponge 303 b and small diameter roll sponge 303 a, fixed to and held by the first and second support portions 304 b, 304 c, respectively, are preferably disposed continuously so that no gap is formed between the sponges, as shown in FIG. 4A.
In the roll sponge assembly 301 of this embodiment, the outer diameter is varied in two stages, but the outer diameter is not limited thereto and may be varied in three or more stages. Furthermore, it goes without saying that the outer diameter and inner diameter of the roll sponge 303, the outer diameter of the support, and so on are not limited to the settings described above.
As shown in FIG. 4A, the scrubbing device according to this embodiment is disposed such that a pair of roll sponge assemblies 301, 301 sandwiches the two surfaces of the substrate 1, as in the first embodiment. Furthermore, the pair of roll sponge assemblies 301, 301 is disposed such that central axes of the respective supports 304, 304 thereof are parallel to each other at a predetermined gap that is smaller than the outer diameter D₁of the large diameter roll sponge 303 b. However, the gap between the supports 304, 304 is not limited to this, and is set appropriately in accordance with various conditions such as the thickness of the substrate and the required cleaning performance.
Similarly to the first embodiment, the cleaning subject substrate 1 moves from the right side to the left side of FIG. 4A between the pair of rotating roll sponge assemblies 301, 301 while being rotated by the plurality of rollers.
The operation to clean the substrate 1 that is performed by the scrubbing device of this embodiment having the constitution described above, and the effects thereof, although basically identical to the first embodiment, will now be described briefly with reference to FIGS. 4A to 4C.
As shown in FIG. 4A, particles of various shapes, sizes and materials are adhered to the surface of the substrate 1 prior to cleaning. In this state, the substrate 1 is inserted between the pair of roll sponge assemblies 301, 301, whereupon scrubbing begins.
As shown in FIG. 4B, in an initial cleaning stage, the outer diameter of the opposing small diameter roll sponges 303 a, 303 a is small, and therefore the contact pressure (pressing force) of the roll sponges 303 a, 303 a against the two surfaces of the substrate 1 is small. Accordingly, particles which are lightly adhered to the surface of the substrate 1 and large particles that can be trapped in the roll sponge 303 a easily even with a weak pressing force are removed from the substrate 1. Furthermore, since the pressing force is small, the trapped particles fall off the roll sponge 303 a easily, and therefore those particles fall away easily due to the action of centrifugal force and so on from the rotating roll sponge 303 a. As a result, no particles substantially remain adhered to the roll sponge 303 a.
Next, as shown in FIG. 4C, the substrate 1 is moved between the pair of large diameter roll sponges 303 b, 303 b, as indicated by the arrow 205. In the state shown in FIG. 4C, the outer diameter of the roll sponge 303 b is large, and therefore the pressing force of the roll sponges 303 b, 303 b against the two surfaces of the substrate 1 increases such that the substrate 1 is scrubbed more forcefully. Large particles are removed when cleaning is performed between the small diameter roll sponges 303 a, 303 a, and therefore at this stage, large particles do not cause scratches and other damages on the surface of the substrate 1 even when the pressing force increases. In addition, an effective cleaning force can be obtained for removing small particles which could not be removed in the previous stage. Moreover, since the outer diameter of the roll sponge 303 b is large, centrifugal force on the outer peripheral surface of the roll sponge 303 b increases, ensuring that small particles adhered to the surface of the roll sponge 303 b fall off the roll sponge 303 b.
Further, since the usage site of the roll sponge 303 varies in the lengthwise direction from 303 a to 303 b in accordance with the cleaning stage of the substrate 1, the maintenance lifespan of the roll sponge 303 can be extended in this embodiment in a similar manner to the first embodiment. Also, recontamination and the reoccurrence of damage such as scratches on the substrate 1 can be avoided in comparison with the related art where only some particular parts are used continuously.
Further, the roll sponge assembly 301 needs only to be provided in a pair, and therefore the rotary driving portions of the device need only to be correspond thereto, enabling an improvement in the maintainability of the device. Furthermore, there is no need for a multi-stage device including a plurality of units, as in the related art. Therefore identical effects to those of a multi-stage device can be obtained in a smaller space.

Fifth Embodiment

FIG. 7B is an exploded view of a roll sponge assembly employed in a scrubbing device according to a fifth embodiment of the present invention.
The roll sponge assembly according to this embodiment basically conforms to the fourth embodiment described above. In other words, the roll sponge assembly of this embodiment has a substantially identical structure to that of the fourth embodiment, and hence there are no substantial differences in the actions and effects in the fourth embodiment and this embodiment.
In this embodiment, as shown in FIG. 7B, a roll sponge assembly 601 includes a roll sponge 603 for cleaning the substrate 1, and a support 604 for supporting the roll sponge 603. In this embodiment, the roll sponge assembly 601 is structured such that the outer diameter of an outside contour thereof varies in stages, similarly to the fourth embodiment.
The roll sponge 603 according to this embodiment has a small diameter part 603 a and a large diameter part 603 b, and the small diameter part 603 a and large diameter part 603 b are formed continuously and integrally. The outer diameter of an outside contour of the small diameter part 603 a of the roll sponge 603 is constant in the lengthwise direction and equal to the minimum outer diameter D₂of the roll sponge 203 according to the first embodiment. The inner diameter of a hollow hole 603 c thereof is also constant in the lengthwise direction, and set at an inner diameter D₅that is slightly larger than the minimum inner diameter D₃of the hollow hole 203 c in the roll sponge 203 of the first embodiment. In this embodiment, the inner diameter D₅of the small diameter part 603 a differs from the fourth embodiment, but the inner diameter of the small diameter part 603 a may be set at D₃, as in the fourth embodiment.
On the other hand, the outer diameter of an outside contour of the large diameter part 603 b of the roll sponge 603 is constant in the lengthwise direction, similarly to the small diameter roll sponge 603 a described above, and equal to the maximum outer diameter D1 of the roll sponge 203 according to the first embodiment. The inner diameter of a hollow hole 603 d in the large diameter part 603 b is constant in the lengthwise direction, similarly to the outer diameter of the outside contour, and equal to the maximum inner diameter D4 of the roll sponge 203 of the first embodiment.
As shown in FIG. 7B, the support 604 of this embodiment includes, from left to right, a left rotary shaft 604 a, a first support portion 604 b, a second support portion 604 c, and a right rotary shaft 604 a.
As shown in FIG. 7B, the left and right rotary shafts 604 a are formed as a solid cylindrical body (column) having a constant outer diameter in the lengthwise direction. The left and right rotary shafts 604 a have an identical outer diameter D₃to the outer diameters of the rotary shafts according to the first through fourth embodiments described above, and are disposed coaxially with the first support portion 604 b and second support portion 604 c. The left and right rotary shafts 604 a are linked to a rotary driving portion (not shown in the drawing). Similarly to the first through fourth embodiments described above, in cooperation with the first and second support portions 604 b and 604 c, the roll sponge assembly 601 can be driven to rotate by means of this mechanism.
The first support portion 604 b is formed as a solid cylindrical body (column) having a constant outer diameter in the lengthwise direction, and has a substantially identical outer diameter D₄to the inner diameter of the hollow hole 603 d in the large diameter part 603 b of the roll sponge. The length of the first support portion 604 b in the lengthwise direction is preferably identical to the length of the large diameter part 603 b of the roll sponge, albeit not limited thereto. The first support portion 604 b is fitted into the hollow hole 603 d in the large diameter part 603 b of the roll sponge 603 so as to fix and hold the large diameter part 603 b of the roll sponge.
The second support portion 604 c fixes and supports the small diameter part 603 a of the roll sponge 603. As shown in FIG. 7B, the second support portion 604 c is also formed as a solid cylindrical body having a constant outer diameter in the lengthwise direction, and has a substantially identical outer diameter D₅to the inner diameter of the small diameter part 603 a of the roll sponge 603. The length of the second support portion 604 c in the lengthwise direction is preferably identical to the length of the small diameter part 603 a of the roll sponge 603. The second support portion 604 c is fitted into the hollow hole 603 c in the small diameter part 603 a of the roll sponge 603 so as to fix and hold the small diameter part 603 a of the roll sponge 603.
Note that in the roll sponge assembly 601 of this embodiment, the outer diameter is varied in two stages, but the outer diameter is not limited thereto and may be varied in three or more stages. Furthermore, it goes without saying that the outer diameter and inner diameter of the roll sponge 603, the outer diameter of the support, and so on are not limited to the settings described above.
As a result, the roll sponge assembly 601 according to this embodiment has a substantially identical shape to the roll sponge assembly 301 according to the fourth embodiment. Therefore, when the roll sponge assembly 601 of this embodiment is applied to a scrubbing device, identical actions and effects to those of the fourth embodiment can be obtained when cleaning the substrate 1.

Sixth Embodiment

FIG. 7C is an exploded view of a roll sponge assembly used in a scrubbing device according to a sixth embodiment of the present invention.
This embodiment basically conforms to the fourth and fifth embodiments, but has been modified to use a single, constant-diameter roll sponge. In other words, this embodiment differs from the fifth embodiment only in the structure of the roll sponge, and all other structures are completely identical to the fifth embodiment.
In this embodiment, as shown in FIG. 7C, a roll sponge assembly 701 includes a roll sponge 703 for cleaning a substrate and a support 704 for supporting the roll sponge 703.
The outer diameter of the outer contour of the roll sponge 703 according to this embodiment is constant in the lengthwise direction and equal to the outer diameter D₂of the small diameter part 603 a of the roll sponge 603 according to the fifth embodiment. The inner diameter of a hollow hole 703 c thereof is also constant in the lengthwise direction, and equal to the inner diameter D₅of the hollow hole 603 c in the small diameter part 603 a of the roll sponge 603 according to the fifth embodiment. Accordingly, the thickness of the roll sponge 703 is also constant in the lengthwise direction.
Hence, the roll sponge 703 is formed as a hollow cylindrical body having a constant outer diameter and a constant inner diameter in the lengthwise direction. Therefore, similarly to the second and fourth embodiments, mass production is possible, thereby enabling a reduction in the manufacturing cost of the scrubbing device in consideration of the fact that the roll sponge 703 is an expendable component of the scrubbing device.
The support 704 of this embodiment has a completely identical shape to that of the fifth embodiment, and therefore description thereof has been omitted.
A first support portion 704 b and a second support portion 704 c are fitted into the hollow hole 703 c of the roll sponge 703 so as to fix and hold the roll sponge 703.
In this embodiment, similarly to the second embodiment, the roll sponge 703 is flexible, and therefore the outside contour of the roll sponge 703 imitates the outside contour of the first support portion 704 b and second support portion 704 c such that the outer diameter thereof varies in a plurality of stages. As a result, the roll sponge assembly 701 according to this embodiment takes a substantially identical shape to the roll sponge assembly 301 of the fourth embodiment.
Hence, when the roll sponge assembly 701 of this embodiment is applied to a scrubbing device, completely identical actions and effects to those of the fourth embodiment can be obtained during substrate cleaning.

Seventh Embodiment

FIG. 7D is an exploded view of a roll sponge assembly employed in a scrubbing device according to a seventh embodiment of the present invention.
This embodiment basically conforms to the fourth embodiment described above, but is modified such that a plurality of roll sponges having hollow holes with identical inner diameters are used. Therefore, this embodiment differs from the fourth embodiment only in that the structure of the roll sponge and support has been simplified, and all other structures are completely identical to the fourth embodiment.
In this embodiment, as shown in FIG. 7D, a roll sponge assembly 801 includes a roll sponge 803 having two roll sponges 803 a and 803 b for cleaning a substrate, and a support 804 for supporting the two roll sponges 803 a and 803 b.
The roll sponge 803 according to this embodiment comprises a small diameter roll sponge 803 a and a large diameter roll sponge 803 b. The outer diameter of the outside contour of the small diameter roll sponge 803 a is constant in the lengthwise direction and equal to the outer diameter D₂of the roll sponge 303 a according to the fourth embodiment. The inner diameter of a hollow hole 803 c thereof is also constant in the lengthwise direction, and identical to the outer diameter D₃of the support 804, as follows. The thickness of the small diameter roll sponge 803 a is constant in the lengthwise direction. On the other hand, the outer diameter of the outside contour of the large diameter roll sponge 803 b is constant in the lengthwise direction similarly to the small diameter roll sponge 803 a described above, but equal to the outer diameter D1 of the roll sponge 303 b according to the fourth embodiment. The inner diameter of a hollow hole 803 d in the large diameter roll sponge 803 b is constant in the lengthwise direction similarly to the outer diameter of the outside contour, and equal to the outer diameter D₃of the support 804, to be described below.
Hence, the roll sponge 803 is formed as a hollow cylindrical body having a constant outer diameter and a constant inner diameter in the lengthwise direction, and therefore mass production is possible, enabling a reduction in the manufacturing cost of the scrubbing device in consideration of the fact that the roll sponge 803 is an expendable component of the scrubbing device.
Similarly to the third embodiment, the support 804 of this embodiment supports the roll sponge 803 (more specifically, the small diameter roll sponge 803 a and the large diameter roll sponge 803 b), and also functions as a rotary shaft of the roll sponge assembly 801. As shown in FIG. 7D, the support 804 is formed as a solid cylindrical body (column) having a constant outer diameter in the lengthwise direction, and has a substantially identical outer diameter D₃to the inner diameter of the small diameter roll sponge 803 a and large diameter roll sponge 803 b. The length of the support 804 is set to be greater than the combined length of the small diameter roll sponge 803 a and large diameter roll sponge 803 b by the length thereof that is used as the rotary shaft. As shown in the drawing, the support 804 of this embodiment has a simple columnar structure, and is therefore easy to manufacture. Note that, in this embodiment, the roll sponge support part and the rotary shaft part of the support 804 are formed with an identical diameter, but the diameters of these parts may be varied appropriately.
The support 804 is fitted into the hollow hole 803 c of the small diameter roll sponge 803 a and the hollow hole 803 d of the large diameter roll sponge 803 b so as to fix and hold the small diameter roll sponge 803 a and large diameter roll sponge 803 b. Further, the part of the support 804 that penetrates the roll sponge 803 and projects from either end is used as the rotary shaft.
As a result, the roll sponge assembly 801 according to this embodiment takes a substantially identical shape to the roll sponge assembly 301 of the fourth embodiment. Hence, when the roll sponge assembly 801 of this embodiment is applied to a scrubbing device, identical actions and effects to those of the fourth embodiment can be obtained during substrate cleaning.

Eighth Embodiment

FIG. 7E is an exploded view of a roll sponge assembly employed in a scrubbing device according to an eighth embodiment of the present invention.
This embodiment basically conforms to the fourth, fifth and seventh embodiments described above.
In this embodiment, as shown in FIG. 7E, a roll sponge assembly 901 includes a roll sponge 903 having two roll sponges 903 a and 903 b for cleaning a substrate, and a support 904 for supporting the two roll sponges 903 a and 903 b.
The roll sponge 903 according to this embodiment comprises a small diameter part 903 a and a large diameter part 903 b, and the small diameter part 903 a and large diameter part 903 b are formed continuously and integrally. The outer diameter of the outside contour of the small diameter part 903 a of the roll sponge 903 is constant in the lengthwise direction and equal to the outer diameter D₂of the small diameter roll sponge 303 a according to the fourth embodiment. On the other hand, the outer diameter of the outside contour of the large diameter part 903 b of the roll sponge 903 is constant in the lengthwise direction similarly to the small diameter roll sponge 903 a described above, but equal to the outer diameter D₁of the large diameter roll sponge 303 b according to the fourth embodiment. The inner diameter of a hollow hole 903 c in the roll sponge 903 is constant in the lengthwise direction similarly to the outer diameter of the outside contour, and equal to the outer diameter D₃of the support 904, to be described below.
Hence, the roll sponge 903 of this embodiment is formed as a hollow cylindrical body having a constant inner diameter in the lengthwise direction, and therefore the roll sponge 903 can be manufactured more easily than the roll sponge 603 of the fifth embodiment, enabling a reduction in the manufacturing cost of the scrubbing device.
Similarly to the third embodiment, the support 904 of this embodiment supports the roll sponge 903 and also functions as a rotary shaft of the roll sponge assembly 901. As shown in FIG. 7E, the support 904 is formed as a solid cylindrical body (column) having a constant outer diameter in the lengthwise direction, and as described above, has a substantially identical outer diameter D₃to the inner diameter of the hollow hole 903 c in the roll sponge 903. The length of the support 904 is set to be greater than the length of the roll sponge 903 by the length thereof that is used as the rotary shaft. As shown in the drawing, the support 904 of this embodiment has a simple columnar structure, and is therefore easy to manufacture. Note that in this embodiment, the roll sponge support portion and the rotary shaft of the support 904 are formed with an identical diameter, but the diameters of these parts may be varied appropriately.
The support 904 is fitted into the hollow hole 903 c of the roll sponge 903 so as to fix and hold the roll sponge 903. Further, the part of the support 904 that penetrates the roll sponge 903 and projects from either end is used as the rotary shaft.
As a result, the roll sponge assembly 901 according to this embodiment has a substantially identical shape to the roll sponge assembly 301 of the fourth embodiment. Hence, when the roll sponge assembly 901 of this embodiment is applied to a scrubbing device, identical actions and effects to those of the fourth embodiment can be obtained during substrate cleaning.
The disclosure of Japanese Patent Application No. 2007-123622, filed on May 8, 2007, is incorporated in the application.
While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.

Claims

1. A roll sponge assembly for a scrubbing device, comprising:

a support having a support portion and a rotary shaft provided on two ends of the support portion, and

a roll sponge having a hollow hole, the support portion of the support being disposed in the hollow hole so that the roll sponge is held on the support,

wherein an outer diameter of the roll sponge assembly continuously gradually increases in a lengthwise direction thereof.

2. A roll sponge assembly for a scrubbing device, comprising:

at least one roll sponge having a hollow hole, the support portion of the support being disposed in the hollow hole so that the roll sponge is held on the support,

wherein an outer diameter of the roll sponge assembly increases in stages in a lengthwise direction.

3. A roll sponge assembly according to claim 1, wherein

an outer diameter of the support portion of the support continuously gradually increases in the lengthwise direction, and

an outer diameter of the roll sponge and an inner diameter of the hollow hole vary continuously in accordance with a variation in the outer diameter of the support portion.

4. A roll sponge assembly according to claim 1, wherein

an outer diameter of the roll sponge and an inner diameter of the hollow hole are constant in the lengthwise direction.

5. A roll sponge assembly according to claim 1, wherein

an outer diameter of the support portion of the support is constant in the lengthwise direction,

an outer diameter of the roll sponge continuously gradually increases in the lengthwise direction, and

an inner diameter of the hollow hole in the roll sponge is constant in the lengthwise direction.

6. A roll sponge assembly according to claim 2, wherein

an outer diameter of the support portion of the support varies so as to increase in stages in the lengthwise direction, and

the at least one roll sponge comprises a plurality of roll sponges formed such that outer diameters thereof and inner diameters of the hollow hole correspond to the outer diameters of the support portion varying in stages, and the respective outer diameters thereof and the inner diameters of the hollow holes are constant in the lengthwise direction.

7. A roll sponge assembly according to claim 2, wherein

an outer diameter of the support portion of the support varies so as to increase in stages in a lengthwise direction, and

an outer diameter of the at least one roll sponge and an inner diameter of the hollow hole vary in stages in accordance with the outer diameter of the support portion varying in stages.

8. A roll sponge assembly according to claim 2, wherein

an outer diameter of the at least one roll sponge and an inner diameter of the hollow hole are constant in the lengthwise direction.

9. A roll sponge assembly according to claim 2, wherein

the at least one roll sponge comprises a plurality of roll sponges formed such that respective outer diameters thereof vary in stages, and the respective outer diameters and an inner diameter of the hollow holes are constant in the lengthwise direction.

10. A roll sponge assembly according to claim 2, wherein

an outer diameter of the at least one roll sponge varies in stages in the lengthwise direction, and

an inner diameter of the hollow hole in the at least one roll sponge is constant in the lengthwise direction.

11. A scrubbing device, comprising:

a plurality of rollers for vertically supporting and rotating a cleaning subject, and

two of said roll sponge assemblies according to claim 1 disposed horizontally and parallel to each other,

wherein the cleaning subject is cleaned by being moved in the lengthwise direction between the roll sponge assemblies rotating simultaneously.

12. A scrubbing device, comprising:

two of said roll sponge assemblies according to claim 2 disposed horizontally and parallel to each other,

13. A cleaning subject scrubbing method, comprising the steps of:

vertically supporting and rotating a cleaning subject using a plurality of rollers,

rotating two roll sponge assemblies disposed horizontally and parallel to each other, each of said roll sponge assemblies including a support having a support portion and a rotary shaft provided on two ends of the support portion, and a roll sponge having a hollow hole, the support portion of the support being disposed in the hollow hole so that the roll sponge is held on the support, wherein an outer diameter of the roll sponge assembly continuously gradually increases in a lengthwise direction thereof, and

moving the cleaning subject between the roll sponge assemblies in the lengthwise direction while the cleaning subject is being rotated by the plurality of rollers.

14. A cleaning subject scrubbing method, comprising the steps of:

vertically supporting and rotating a cleaning subject using a plurality of rollers;

rotating two roll sponge assemblies disposed horizontally and parallel to each other, each of said roll sponge assemblies including a support having a support portion and a rotary shaft provided on two ends of the support portion, and at least one roll sponge having a hollow hole, the support portion of the support being disposed in the hollow hole so that the roll sponge is held on the support, wherein an outer diameter of the roll sponge assembly increases in stages in a lengthwise direction, and