Patent Application
20050205117
1. Field of the Invention
The present invention relates to a method and a device for removing dust from a surface of a support, and more particularly to a method and a device for removing dust from a surface of a support that is conveyed through a conveyance path such as a coating line or a printing line that requires high cleanliness.
2. Related Art
A conveyance path of a coating line in which a coating liquid containing water or a solution as a solvent such as a photosensitive liquid, a magnetic fluid, or a solution coating is applied to a band-like flexible support (hereinafter referred to as a “web”) and dried requires high cleanliness because the web is most likely to be exposed to dust in the conveyance path. Thus, a room in which the coating line is placed has been designed to be a clean room.
In this case, however, the entire room must be designed to be a clean room, thereby increasing construction costs. Also, ventilation by clean air must be provided in the entire room, which requires a large amount of clean air, thereby increasing running costs.
To solve these problems, the entire coating line is surrounded by a casing, and clean air is supplied into the casing to reduce a capacity required for ventilation. The method of surrounding the entire coating line by the casing can reduce costs as compared with the case where the entire room is designed to be a clean room, but in the casing, a bearing, a slide rail, a rack, an elevator, an air cylinder, or the like that generate dust are provided in addition to a web or a roll, and in some cases, a drive unit such as a motor, a belt, a gear, or a coupling is provided. These devices generate dust, and dust is also accumulated on the devices, which prevents an increase in cleanliness.
Further, a dead zone through which no clean air flows is likely to be formed. Thus, even by the method of surrounding the entire coating line by the casing, the web is most likely to be exposed to dust, and a conveyance path that requires high cleanliness cannot be maintained at desired cleanliness.
In view of such circumstances, the applicant of the invention has proposed a dust removing device for a subject to be conveyed capable of efficiently removing dust at low costs (see Japanese Patent Application Laid-open No. 2003-26326). This device is adapted to surround a conveyance path of a web only to maintain cleanliness near the web, and it is confirmed that a certain advantage can be obtained by the device.
However, even with such a device, the surrounding of the conveyance path must be opened for handling in such a case when the web is cut, which may reduce cleanliness near the web to contaminate the web.
The invention has been achieved in view of the above described circumstances, and has an object to provide a method and a device for removing dust from a surface of a support capable of efficiently removing dust at low costs from a subject to be conveyed (a support) that is conveyed through a conveyance path provided in an anti-dust line that is sensitive to dust such as a coating line or a printing line.
In order to achieve the object, the invention provides a method for removing dust from a surface of a support, comprising the steps of: placing a plate-like body on a surface of a traveling band-like support so as to face the surface at a predetermined distance; supplying a gas with cleanliness of class 10 or less between the support and the plate-like body; and forming a pressurized space at atmospheric pressure or higher between the support and the plate-like body, and a device for the method.
According to the invention, the clean gas is supplied between the support and the plate-like body to form the pressurized space, thereby preventing the surface of the support from being exposed to dust and allowing a conveyance path to be maintained at desired cleanliness. Specifically, the pressurized space between the support and the plate-like body is at the atmospheric pressure or higher, thereby preventing dust from being introduced.
The conveyance path in which the support is most likely to be exposed to dust may have a small capacity, thereby preventing reduction in speed of the clean gas and preventing a dead zone in which no clean gas flows from being formed. This allows dust to be effectively removed from the support with a small amount of clean gas. The conveyance path in which the support is most likely to be exposed to dust can be maintained at the desired cleanliness, thereby reducing an amount of clean gas used for the entire anti-dust line.
As the support, the band-like flexible support (web) as described above is generally used, but the advantage of the invention may be obtained with a plate-like body such as a glass substrate or a silicone wafer.
As the clean gas, clean air is generally used, but gases such as a nitrogen gas or an argon gas may be used.
In the invention, it is preferable that a width of the plate-like body is equal to or larger than a width of the support, a slit is formed in the plate-like body in a traveling direction of the support, and the gas with the cleanliness of class 10 or less is supplied through the slit. With such a configuration, the clean gas supplied through the slit in the plate-like body forms the pressurized space to allow the conveyance path to be maintained at desired cleanliness.
In the invention, it is preferable that a width of the plate-like body is equal to or larger than a width of the support, a slit is formed in the plate-like body perpendicularly to a traveling direction of the support, and the gas with the cleanliness of class 10 or less is supplied through the slit. With such a configuration, the clean gas supplied through the slit in the plate-like body forms the pressurized space to allow the conveyance path to be maintained at desired cleanliness.
In the invention, it is preferable that a width of the plate like body is equal to or larger than a width of the support, multiple air supply holes are formed in the plate-like body, and the gas with the cleanliness of class 10 or less is supplied through the air supply holes. With such a configuration, the clean gas supplied through the multiple air supply holes forms the pressurized space to allow the conveyance path to be maintained at desired cleanliness.
In the invention, it is preferable that a width of the plate-like body is equal to or larger than a width of the support, a surface of the plate-like body is formed of a permeable member, and the gas with the cleanliness of class 10 or less is supplied through the permeable member. With such a configuration, the clean gas supplied through the surface of the plate-like body that is the permeable member forms the pressurized space to allow the conveyance path to be maintained at desired cleanliness.
In the invention, it is preferable that the pressurized space at atmospheric pressure or higher is formed between a coating side surface of the support and the plate-like body before and/or after a coating film with a thickness at coating of 10 μm or less is formed on the surface of the support by a coating device. The pressurized space is formed in the conveyance path before and after the coating device to provide an advantage of an anti-dust line.
In the invention, it is preferable that the pressurized space at atmospheric pressure or higher is formed between the support and the plate-like body after the surface of the support is cleaned. The pressurized space is formed in the conveyance path after the cleaning (dust removing) to provide an advantage of the anti-dust line. As a device for “cleaning the surface of the support”, various types of known devices may be used such as a high speed air blow device with ultrasonic sounds, an adhesive roller, or a round bar immersed in a solution.
As described above, according to the invention, the clean gas is supplied between the support and the plate-like body to form the pressurized space, thereby preventing the surface of the support from being exposed to dust and allowing the conveyance path to be maintained at desired cleanliness.
Now, a preferred embodiment (a first embodiment) of a method and a device for removing dust from a surface of a support according to the invention will be described in detail with reference to the accompanying drawings.
In a film manufacturing line 10, a web W is fed from a feeder 66 as shown in
A coating device 14 is provided downstream of the dust removing conveyance path 12, and can apply a coating liquid to the web W. The coating device 14 is an extrusion-type coater. A drying zone 76 is provided downstream of the coating device 14, and can dry a coating layer formed on the web W. Then, the web W on which the coating layer is formed is wound by a winder 82 provided downstream of the drying zone 76.
The dust remover 74 that is a device for cleaning the surface of the support includes a remover using a dry-type dust removing method and a remover using a wet-type dust removing method.
The dry-type dust removing method includes a method of pressing a nonwoven fabric or a blade on the surface of the web W, a method of blowing air with high cleanliness on the surface of the web W at high speed to peel deposits off the surface and sucking the deposits into an adjacent suction port for removal, and a method of bringing an adhesive roller into contact with the traveling web W and removing deposits on the surface of the web W.
The wet-type dust removing method includes a method of pressing a nonwoven fabric or a blade on the web W while a solution remains on the web W after the solution is applied thereto, or a method of pressing a rod member that rotates in an opposite direction from a conveying direction of the web W on the surface of the web W while a solution remains on the web W after the solution is applied thereto to scrape deposits off the surface.
Further, the applicant of the invention has proposed a method and a device for removing dust from a web including a combination of a dry-type dust removing method and a wet-type dust removing method (Japanese Patent Application Laid-open No. 2002-79200), and it is confirmed that a certain advantage can be obtained by the method and the device. Thus, such a method and a device for removing dust from a web may be used.
Next, the dust removing conveyance path 12 that is a characteristic feature of the invention will be described.
The clean air hits the surface (a lower surface) of the web W at a position facing the slit 20A (18A, 22A), and is divided into right and left sides to flow in the directions of arrows and flow outside from edges of the web W. The flow of the clean air forms the pressurized space at atmospheric pressure or higher between the web W and the plate-like body 20 (18, 22), thereby preventing the surface (lower surface) of the web W from being exposed to dust and allowing the dust removing conveyance path 12 to be maintained at high cleanliness.
As shown in
In the dust removing conveyance path 12, values such as a size and a material of the plate-like body 20 (18, 22), a size of the slit 20A (18A, 22A), the distance between the web W and the plate-like body 20 (18, 22), and a flow rate of the clean air are appropriately determined depending on a conveying speed of the web W, a substance of the coating liquid, a thickness of the coating film, specifications of a product, required cleanliness, or the like.
Next, a coating device 14 placed downstream of the dust removing conveyance path 12 will be described.
The coating head 28 is placed in such a manner that a tip of the coating head closely faces the continuously traveling web W. Specifically, as shown in
As shown in
The coating slit 28C is a narrow passage connecting the pocket 28B and the tip of the coating head, and is extended along the width of the web W. Then, a coating liquid of a desired coating amount to be applied to the web W is supplied from the supply line 28A to the coating pocket 28B of the coating head 28.
In
The coating device 14 in
Next, a film manufacturing method using the film manufacturing line in
Then, the web W is passed through the dust removing conveyance path 12 until the web W is conveyed to the coating device 14. In the dust removing conveyance path 12, the flow of the clean air forms the pressurized space at atmospheric pressure or higher between the web W and the plate-like bodies 18, 20 and 22, thereby preventing the surface (lower surface) of the web W from being exposed to dust and allowing the dust removing conveyance path 12 to be maintained at high cleanliness.
Then, the coating liquid is applied to the web W by the coating device 14. The web W is then passed through the drying zone 76 and wound by the winder 82.
Next, a second embodiment of the invention will be described in detail.
In
Next, a film manufacturing method in the second embodiment of the invention will be described. Components other than a dust removing conveyance path 12 are the same as those in the first embodiment, and thus the dust removing conveyance path 12 only will be described.
The web W is passed through the dust removing conveyance path 12 from a dust remover 74 to a coating device 14. In the dust removing conveyance path 12, the clean air hits a surface (a lower surface) of the web W at positions facing the slits 120A and 120A, flows together with the web W as shown by arrows, and is divided into right and left sides and flow outside from edges of the web W. The flow of the clean air forms a pressurized space at atmospheric pressure or higher between the web W and the plate-like body 120, thereby preventing the surface (lower surface) of the web W from being exposed to dust and allowing the dust removing conveyance path 12 to be maintained at high cleanliness.
Next, a third embodiment of the invention will be described in detail.
In
Next, a film manufacturing method in the third embodiment of the invention will be described. Components other than a dust removing conveyance path 12 are the same as those in the first embodiment, and thus the dust removing conveyance path 12 only will be described.
The web W is passed through the dust removing conveyance path 12 from a dust remover 74 to a coating device 14. In the dust removing conveyance path 12, the clean air hits a surface (a lower surface) of the web W, flows together with the web W as shown by arrows, and is divided into right and left sides to flow in the directions of arrows and flow outside from edges of the web W. The flow of the clean air forms a pressurized space at atmospheric pressure or higher between the web W and the plate-like body 220, thereby preventing the surface (lower surface) of the web W from being exposed to dust and allowing the dust removing conveyance path 12 to be maintained at high cleanliness.
The embodiments of the method and the device for removing dust from a surface of a support according to the invention have been described, but the invention is not limited to the embodiments, and various aspects may be adopted.
For example, in the embodiments, the three types of plate-like bodies 20, 120 and 220 have been described, but plate-like bodies having other configurations may be used. By way of example, a surface of a plate-like body may be formed of a permeable member so that a gas with cleanliness of class 10 or less is supplied through the permeable member. As such a permeable member, porous ceramics, porous fluororesin, or the like may be preferably used.
For the numbers or layouts of the plate-like bodies 20, 120 and 220, various configurations other than the embodiments may be used.
The film manufacturing line 10 in
As the web W, a PET film having a width of 300 mm and a thickness of 10 μm was used. A traveling speed of the web W was fixed to 100 m/min.
The dust remover 74 used was of the type that blows air with high cleanliness on the surface of the W at high speed to peel deposits off the surface, and sucks the deposits into an adjacent suction port for removal.
Viscosity of the coating liquid applied by the coating device 14 was 0.02 Pas (20 cP), and a coating film thickness (a wet film thickness) was 8 μm.
As the plate-like body used in the dust removing conveyance path 12, three types of plate-like bodies: the plate-like body 20 (18, 22) in
For the plate-like body 20 (18, 22) in
For the plate-like body 120 in
For the permeable member instead of the plate-like body 220 in
As a method for evaluating advantages obtained by using various types of plate-like bodies in the dust removing conveyance path 12, measurement of cleanliness near the web W and determination of the presence of coating defects (streak defects) in the application of the coating liquid were used.
In the measurement of the cleanliness, a laser particle counted manufactured by Transtech Co., Ltd. was used to measure the number of dust particles having sizes from 0.5 to 3.0 μm. A summary of the measurement results of the cleanliness was provided in the table in
The determination of the presence of the coating defects (streak defects) was performed by visual check. Streaks produced in a length of 10 m of the web W were counted under a halogen lamp, and an average value of five measurements was calculated to determine the presence of the defects. A summary of the average values of the streak defects was provided in the table in
According to the table in
According to the table in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-78451 | Mar 2004 | JP | national |
