KR101042318B1 - Chemical collecting apparatus and chemical coating apparatus with it - Google Patents

Abstract

The present invention relates to a chemical liquid recovery device and a chemical liquid applying device having the same. The chemical liquid recovery apparatus recovers a chemical liquid having a low dielectric constant. The chemical liquid collection device includes a leveling pipe to detect the level of the chemical liquid, a metallic thin film attached to one side of the leveling pipe to increase capacitance, and a plurality of sensors installed on the other side of the leveling pipe to detect the level of the chemical liquid. do. The metallic thin film is attached to the leveling tubing against the position of the sensors. According to the present invention, by increasing the capacitance between the chemical liquid and the capacitive sensor by the metallic thin film, it is possible to use the low-capacitance capacitance sensors, through which it is possible to accurately detect the liquid level of the chemical liquid recovery tank, Cost reduction, installation and maintenance are easier than using capacitive sensors or optical sensors.

Chemical application device, inkjet printing unit, chemical recovery device, capacitive sensor, thin film

Description

TECHNICAL COLLECTING APPARATUS AND CHEMICAL COATING APPARATUS WITH IT

The present invention relates to a chemical liquid application device, and more particularly, to a chemical liquid recovery device for detecting a level of the chemical liquid having a low dielectric constant using capacitive sensors and a chemical liquid application device having the same.

In order to manufacture the color filter of a liquid crystal display device, the chemical | medical agent coating apparatus which discharges a chemical | medical solution on the surface of a glass substrate apply | coats a chemical | medical solution by the inkjet method. Such a chemical liquid applying apparatus has a plurality of inkjet heads. The inkjet head has a nozzle face in which one nozzle is provided with a plurality of nozzles for ejecting the chemical liquid to the substrate surface.

In the inkjet head, the chemical liquid remaining on the nozzle surface is hardened during chemical liquid ejection or in the air, and the nozzles are frequently clogged. To solve this problem, the chemical liquid applying apparatus is provided with cleaning devices for cleaning the nozzle surface. For example, the cleaning apparatus includes a plurality of blades for removing the chemical liquid remaining on the nozzle surface in a non-contact manner, a purge tank for collecting the chemical liquid removed by the blades or discharged from the nozzles; , Wipers and the like.

The purge tank is connected with the chemical liquid recovery tank. The chemical liquid recovery tank receives the chemical liquid from the purge tank, collects and stores the chemical liquid, and processes the chemical liquid stored therein using a waste liquid container. Therefore, the chemical liquid recovery tank needs to detect the level of the chemical liquid in order to receive the chemical liquid from the purge tank or to stop the chemical liquid supply. In addition, the chemical liquid collection tank needs to detect the level of supplying the chemical liquid to the waste liquid container. To this end, the chemical liquid recovery tank is provided with a plurality of sensors installed in the cylindrical leveling pipe provided on one side for detecting the level of the chemical liquid.

The chemical liquid of the chemical liquid recovery tank is black because it is a mixed liquid in which chemical liquids of different R, G, and B colors are mixed from the respective inkjet heads. In addition, this chemical is highly viscous and the substrate is a chemical solution, so foreign substances are included. Therefore, the chemical liquid is often viscous foreign matter inside the leveling pipe. In addition, since the chemical liquid contains a strong solvent component, the dielectric constant is low, so it is difficult to accurately detect the water level using an optical sensor. In addition, since the leveling pipe is cylindrical, the cross-sectional area detected by the sensors from the outside narrows the sensitivity.

Therefore, it is necessary to detect the liquid level of the chemical recovery tank by using a high capacity capacitive sensor or a sensitive sensor such as an optical fiber sensor, which makes the configuration and installation complicated and increases the manufacturing cost. There is a problem.

An object of the present invention is to provide a chemical liquid recovery device for detecting the level of the chemical liquid having a low dielectric constant using low capacitance capacitance sensors, and a chemical liquid applying device having the same.

Another object of the present invention is to provide a chemical liquid recovery device for detecting the level of the chemical liquid having a low dielectric constant by increasing the capacitance, and a chemical liquid applying device having the same.

Still another object of the present invention is to provide a chemical liquid recovering device having a reduced manufacturing cost, easy to install and maintain, and a chemical liquid applying device having the same.

In order to achieve the above objects, the chemical liquid recovery apparatus of the present invention is characterized by increasing the capacitance of the site for measuring the level of the chemical liquid having a low dielectric constant. Such a chemical liquid collection device may detect the level of the chemical liquid using a low capacitance capacitance sensor.

According to this aspect, there is provided a chemical liquid recovery apparatus comprising: a chemical liquid recovery tank for storing waste liquid of a chemical liquid; A leveling pipe installed at the chemical liquid recovery tank and having a metallic thin film attached to one side in an up and down direction; It is disposed on the other side of the leveling pipe and includes a plurality of sensors for detecting the level of the waste liquid of the chemical liquid recovery tank by increasing the capacitance with the waste liquid contained in the leveling pipe by the thin film.

In one embodiment, the chemical liquid recovery apparatus; A guide in which the sensors are installed; It is installed on the guide further comprises a control member for adjusting the distance between the sensors and the thin film, or to adjust the vertical position of each of the sensors.

In another embodiment, the guide; A through hole extending vertically opposite to the longitudinal direction of the leveling pipe and extending in the longitudinal direction of the guide is provided so that the sensors are inserted into the through hole.

In another embodiment, the adjustment member is rotated left and right along the inner surface of the through hole to fix or separate each of the sensors to the guide.

In yet another embodiment, the thin film is attached to positions respectively measuring waste level in the leveling piping corresponding to the sensors.

In another embodiment, the thin film is extended in the vertical direction between the positions for measuring the waste liquid level of the leveling pipe corresponding to the sensors.

In yet another embodiment, the sensors are equipped with capacitive sensors.

According to another feature of the invention, there is provided a chemical liquid applying device for sensing the level of the chemical liquid using the capacitive sensors. Such a chemical liquid applying apparatus of the present invention can accurately detect the level of the chemical liquid to reduce the manufacturing cost, easy installation and maintenance.

The chemical liquid applying device according to this aspect comprises: a plurality of heads having a nozzle surface provided with a plurality of nozzles receiving the chemical liquid and discharging the chemical liquid to an upper surface of the object; A purge tank collecting the chemical liquid provided from the heads; A chemical liquid recovery tank for receiving and storing the chemical liquid from the purge tank; A leveling pipe installed at one side of the chemical liquid recovery tank; A metallic thin film attached to one side of the leveling pipe; It includes a plurality of capacitive sensors for sensing the level of the chemical liquid of the chemical liquid recovery tank by increasing the capacitance with the chemical liquid accommodated in the leveling pipe by the thin film.

In one embodiment, the chemical applying device; A guide in which the capacitive sensors are installed; It is installed on the guide further comprises a control member for adjusting the distance between the capacitive sensors and the thin film, or to adjust the vertical position of each of the sensors.

In another embodiment, the guide; A through hole extending vertically opposite to the longitudinal direction of the leveling pipe and extending in the longitudinal direction of the guide is provided, and the capacitive sensors are inserted into the through hole.

In yet another embodiment, the adjusting member; It is rotated left and right along the inner surface of the through hole to fix or separate each of the sensors to the guide.

In yet another embodiment, the purge tank; A plurality of blades provided at an upper portion corresponding to the heads spaced apart from and parallel to the nozzle face of each of the heads to remove the chemical liquid remaining on the nozzle face in a non-contact manner with the nozzle face; . Here, the purge tank collects and stores the chemical liquid removed by the blade.

As described above, the chemical liquid recovering apparatus of the present invention can increase the capacitance between the chemical liquid having a low dielectric constant and the capacitance sensor by attaching a metallic thin film corresponding to the buoy for measuring the level of the chemical liquid.

In addition, the chemical liquid recovering apparatus of the present invention increases capacitance by using a metallic thin film, thereby enabling the use of low-capacity capacitive sensors, through which the liquid level of the chemical liquid collection tank can be accurately detected, and a high-capacitance capacitive sensor Cost savings and installation and maintenance are easier than using optical sensors.

The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be interpreted as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes and the like of the components in the drawings are exaggerated in order to emphasize a clearer explanation.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1 to 8.

1 is a view showing a schematic configuration of a chemical liquid applying apparatus according to the present invention.

Referring to FIG. 1, a chemical liquid applying apparatus 100 is a facility for applying a chemical liquid to an upper surface of an object by an inkjet method, and includes an inkjet printing unit 110 according to the present invention. The object may be a rectangular flat plate, for example, a glass substrate for manufacturing a color filter, an alignment film, or the like of a liquid crystal display panel, a printed circuit board for forming a metal thin film on a circuit pattern, and And a plate for printing the chemical liquid by an inkjet method. In the embodiment of the present invention will be described in detail using a glass substrate (S) for producing a color filter as an object.

The chemical liquid applying apparatus 100 draws a substrate from an inkjet printing unit 110 that prints a substrate surface by an inkjet method, a loader 102 on which a plurality of substrates are loaded, and the loader 102 and inkjet printing. An index 106 for supplying the unit 110, a baker and oven 108 for receiving and baking a substrate coated with a chemical liquid from the index 106, and an unloader for loading the baked substrate. (unloader) 104. The index 106 is equipped with a transfer robot (not shown) for transferring a substrate between the loader 102, the inkjet printing unit 110, the baking unit 108, and the unloader 104. The chemical liquid applying apparatus 100 includes a chemical liquid supply unit 105 for supplying a chemical liquid to the inkjet printing unit 110. Moreover, the chemical | medical agent application apparatus 100 is a full-length control part, and is equipped with the main control part 101 which controls the general operation | movement of the chemical | medical solution application apparatus 100. As shown in FIG.

Specifically, FIGS. 2 and 3 are diagrams showing the configuration of the inkjet printing unit.

2 and 3, the inkjet printing unit 110 is an apparatus for applying a chemical liquid to the surface of the substrate S by an inkjet method, and includes a steel base 116 and a stage disposed on the base 116. And a head assembly 200 having a plurality of inkjet heads 210 disposed on the stage 112 and applying a chemical to a surface of the substrate S seated on the stage 112. And a gantry 114 supporting 200. In addition, the inkjet printing unit 110 includes a plurality of dustproof members 113 for blocking vibration between the base 116 and the stage 112.

The head assambly 200 is provided as a multi head array (MHA) unit. The head assembly 200 is coupled to a plurality of inkjet heads 210 (210a to 210c) for ejecting a chemical liquid by an inkjet method, a bracket 202 on which the inkjet heads 210 are installed, and a bracket 202 to be combined with the head assembly. And a drive unit 204 for moving the 200 in at least one direction.

For example, a plurality of inkjet heads 210 are provided in two rows on the front and rear surfaces of the bracket 202. That is, a plurality of inkjet heads 210 are arranged side by side on both front and rear sides of the bracket 202 in the Y-axis direction. Each of the inkjet heads 210 may be connected to a chemical liquid supply part 105 of FIG. 1 to receive chemical liquids. Each of the inkjet heads 210 may be supplied with the same or different chemicals.

The inkjet head 210 is a device for discharging the chemical liquid to the surface of the substrate (S), each of the inkjet head 210 has a head (212 in FIG. 4) at the bottom. The head 212 has a nozzle surface provided with a plurality of nozzles (not shown) for supplying a chemical liquid to the substrate S on a lower surface facing the substrate S surface. When the object is the substrate S for the color filter, the inkjet heads 210 respectively supply one of R, G, and B color chemicals. At this time, the chemical liquids are inks of R color, G color, and B color.

The driving unit 204 is coupled to the bracket 202 in which the inkjet heads 210 are installed, and the first guide members 150 and 152 and the head assembly 200 for moving the head assembly 200 in the Y-axis direction. And a second guide member 206 for moving in the X axis direction, and a driving unit (not shown). The drive unit 204 is moved along the support 114 in the Y axis direction or the X axis direction. The drive unit 204 also moves the head assembly 204 in the Z axis direction. In addition, the driving unit 204 rotates about the central axis of each of the inkjet heads 210.

The stage 112 is provided as a stone plate, the chucking unit 120 is disposed on the upper side and chucking the substrate S, and the cleaning unit 130 is disposed on the other side to clean the head assembly 200. , 140). The chucking unit 120 linearly moves toward the index 106 to receive the substrate S. When the substrate S is seated, the chucking unit 120 chucks to move to the opposite side of the index 106, that is, to a position to apply the chemical to the substrate S. It includes a chuck 124, a chuck driver 126 for moving or rotating the chuck 124 in at least one linear direction, and a third guide member 122 for guiding the chuck 124 in a linear movement. The chuck 124 has a lower portion coupled to the chuck driver 126 and linearly moved along the third guide member 122 in the Y axis direction.

In addition, the stage 112 is provided with first guide members 150 and 152 corresponding to both ends of the support 114. The first guide members 150 and 152 extend along the Y axis direction to have the same width as the stage 112. The first guide members 150 and 152 are elongated at the upper ends of the stage 112 along the Y axis direction to linearly move the support 114 in the Y axis direction.

Support 114 is coupled to the drive unit 204 on one side and the slider 154 is coupled to the lower side of both sides, to move the head assembly 200 in the Y-axis or X-axis direction. To this end, the support 114 drives the second guide member 206 and the driving unit 204 to move along the second guide member 206 so that the head assembly 200 is linearly moved in the X axis direction. (Not shown) (for example, a motor, a gear, a pulley, a belt, a ball screw, a linear motor) and the like. The upper side of the support 114 is provided with a pressure control unit 118 that controls the overall operation of the inkjet printing unit 110, for example, pressure control, chemical liquid supply and discharge. The support 114 has the same width as the stage 112 in the X axis direction. That is, the support 114 is coupled to the slider 154 at both ends thereof, and the slider 154 is provided to be movable in the Y axis direction along the first guide members 150 and 152. The support 114 also linearly moves the drive unit 204 in the X-axis direction so that the head assembly 200 can be moved in the X-axis direction.

The chemical liquid applying apparatus 100 moves the head assembly 200 to a position 200a corresponding to the cleaning parts 130 to 140 in order to clean the inkjet head 210.

That is, the maintenance zones 130 to 140 may include a first cleaning unit 130 for primary cleaning of the plurality of inkjet heads 210, and a nozzle surface from which the chemical liquids of the inkjet heads 210 are discharged. And a second cleaning unit 140 for secondary cleaning.

The first cleaning unit 130 includes a plurality of blades 132 for removing the chemical liquid remaining on the nozzle surface in a non-contact manner, and a purge tank for collecting the chemical liquid removed by the blades 132. 134. In addition, the purge tank 134 is located in the upper portion of the first cleaning unit 130, the inkjet head 210, in order to prevent the nozzles are clogged by the chemical liquid, by pressing the internal pressure of the inkjet head 210 When the remaining chemical liquids are spitting, the discharged chemical liquids are collected. The purge tank 134 is provided with a plurality of cleaning nozzles 170 inside the upper end. The cleaning nozzles 170 receive the cleaning liquid and discharge the inside of the purge tank 134 to clean the purge tank 134.

The purge tank 134 is connected to the chemical liquid recovery device (180 of FIG. 4) installed at the bottom. The chemical liquid recovery device 180 receives and stores a mixed liquid of the chemical liquid stored in the purge tank 134 and the cleaning liquid that has been cleaned inside the purge tank 134. In this case, the chemical liquid is a mixed liquid in which chemical liquids of different R, G, and B colors are mixed from the inkjet heads 210.

The blades 132 are installed on top of the purge tank 134. The blades 132 are provided in plurality in correspondence with the inkjet head 210. The blade 132 removes the chemical liquid in a non-contact manner with the nozzle surface in order to remove the chemical liquid formed on the nozzle surface of the inkjet head 210.

The second cleaning unit 140 cleans the nozzle surface 242 from which the chemical liquid is removed from the first cleaning unit 130 by using a roll type wiper 142. In cleaning, the wiper 142 is in contact with the nozzle face 242.

When the head assembly 200 is moved in the X-axis direction by the driving unit 204 and moved to the other side of the stage 112, the cleaning units 130 to 140 firstly inkjet the upper portion of the first cleaning unit 130. The head 210 moves in the Y-axis direction to be positioned. The inkjet head 210 removes the chemical liquid on the nozzle surface 242 by the blade 132 by linearly moving while maintaining a predetermined interval on the blade 132. At this time, the chemical liquid removed from the nozzle surface 242 is collected in the purge tank 134. Subsequently, the inkjet head 210 is moved in the Y-axis direction and positioned above the second cleaning unit 140. The wiper 142 of the second cleaning unit 140 is brought into contact with the nozzle face 242 of the inkjet head 210, and the wiper 142 is rotated to clean the nozzle face 242.

In addition, the pressure controller 118 may include a Pressure Control (MPC) unit for adjusting the internal pressure of the inkjet head 210. The pressure controller 118 adjusts the internal pressure of the inkjet head 210 to a negative pressure, and controls the plurality of piezoelectric elements (not shown) individually to supply the chemical liquid to uniformly discharge the chemical liquid from each nozzle. do.

Next, the structure of the chemical | medical solution collection | recovery apparatus which concerns on embodiment of this invention is demonstrated using FIGS.

4 is a view showing the configuration of the chemical liquid recovery apparatus according to an embodiment of the present invention, Figures 5 to 7 are views showing the configuration of the sensor unit for detecting the level of the chemical liquid shown in FIG.

Referring to FIG. 4, the chemical liquid recovery device 180 includes a chemical liquid recovery tank 186, a leveling pipe 182, and a plurality of sensor units 190 (190a to 190c). The chemical liquid recovery tank 186 is installed below the stage 112. For example, the chemical liquid recovery tank 186 is installed between the stage 112 and the base 116. The chemical liquid recovery tank 186 is connected to the purge tank 134 installed on the stage 112. The chemical liquid recovery tank 186 receives the chemical liquid through the drain pipe 138 connected to the drain port provided at the lower end of the purge tank 134. The chemical liquid recovery tank receives fumes generated inside the purge tank 134 through an exhaust port provided at one side of the purge tank 134.

The chemical liquid recovery tank 186 receives the chemical liquid from the purge tank 134 and fills it with a predetermined level, and supplies the chemical liquid to the waste liquid container 300. To this end, the chemical liquid recovery tank 186 is provided with a pump 188 at the chemical liquid discharge end. The waste liquid container 300 receives the chemical liquid from the chemical liquid recovery tank 186 through the pump 188.

The chemical liquid recovery tank 186 is provided with a leveling pipe 182 on one side for measuring the level of the chemical liquid. Both ends of the leveling pipe 182 are respectively provided at the upper end and the lower end of the chemical liquid recovery tank 186. The leveling pipe 182 is provided with a plurality of sensor units 190 (190a to 190c) at positions for measuring the level of the chemical liquid. For example, the sensor units 190 may be provided with a liquid level supplied from the purge tank 134, a liquid level for supplying the chemical liquid from the chemical liquid recovery tank 186 to the waste liquid container 300, and from the purge tank 134. It is installed at each position to detect the level and the like to stop the supply of the chemical liquid.

Here, the chemical liquid of the chemical liquid recovery tank 186 has a black color because the chemical liquids of different R, G, and B colors are mixed from the respective inkjet heads, or the liquid mixture of the chemical liquids of different colors with the cleaning liquid is black. In addition, this chemical is highly viscous and the substrate is a chemical solution, so foreign substances are included. Therefore, the chemical liquid is often adhered to the viscous foreign matter inside the leveling pipe (182). In addition, since the chemical liquid contains a strong solvent component, the dielectric constant is low, so it is difficult to detect an accurate water level using a capacitive sensor or an optical sensor of low capacity.

In order to solve this problem, the sensor units 190: 190a to 190c may be formed of the metallic thin film 194 attached to one side of the leveling pipe 182 and the leveling pipe 182, as shown in FIGS. 5 and 6. The other side includes a plurality of capacitive sensors 192.

The metallic thin film 194 is provided with, for example, silver foil tape made of aluminum. For example, the metallic thin film 194 may have a width D of about 10 mm. This decreases or causes malfunction of the capacitive sensor 192 when the value is less than or exceeded about 10 mm. In addition, the metallic thin film 194 is extended to the same length in the longitudinal direction of the leveling pipe 182 or the position for sensing the level of the chemical liquid 184 of the leveling pipe 182 is attached to one side of the leveling pipe 182.

Here, the operation principle of the capacitive sensor is as follows.

That is, referring to FIG. 8, the magnitude of the capacitance C of the capacitor in which the two electrodes (ie, the object and the pole plate) are parallel is proportional to the area A of the object and inversely proportional to the distance d between the electrodes. . If the dielectric between the object and the pole plate has a dielectric constant epsilon, the capacitance C becomes C = ε * A / d. Therefore, the larger the surface area of the electrode, the narrower the gap, and the larger the dielectric constant of the dielectric, the larger the capacitance.

In addition, as illustrated in FIG. 7, the sensor unit 190 includes a guide 196 in which a plurality of capacitive sensors 192 are adjustable in the vertical direction or the front-back direction in response to the level of the chemical liquid 184 to be measured. And an adjustment member 198 installed on the guide 196 to adjust the distance between the capacitive sensor 192 and the metallic thin film 194 or to adjust the vertical position of the capacitive sensor 192. The guide 196 extends up and down opposite to the longitudinal direction of the leveling pipe 182. Guide 196 is provided with a through hole (not shown) extending in the longitudinal direction. The capacitive sensors 192 are inserted into the through holes and fixed to the guide 196 by the adjusting member 198. The adjusting member 198 is, for example, provided in the form of a screw and rotated left and right along the inner surface of the hole so that the capacitive sensor 192 is fixed to or separated from the guide 196. Therefore, the capacitive sensor 192 can be positioned in the front and rear or up and down directions by the adjustment member 198.

The sensor unit 190 of the present invention is attached to the metal thin film 194 in one longitudinal direction of the leveling pipe 182, the plurality of capacitive sensors 192 are installed on the other side of the leveling pipe 182 spaced apart from each other do. Each of the capacitive sensors 192 increases the capacitance (charge amount) between the chemical thin film 194 and the chemical liquid 184 inside the leveling pipe 182. Therefore, the charge of the low-capacity solvent-based chemical liquid 184 increases the charge concentration by the metallic thin film 194, thereby improving the sensitivity of the capacitive sensor 192.

The chemical liquid recovery device 180 accurately detects the chemical liquid level of the chemical liquid recovery tank 186 by using the capacitive sensors 192 having a low capacity, thereby reducing the cost than using a high capacity capacitive sensor or an optical sensor, Easy to install and maintain

In the above, the configuration and operation of the chemical liquid recovery apparatus and the chemical liquid applying apparatus having the same according to the present invention has been shown in accordance with the detailed description and the drawings, which are merely described by way of example, but do not depart from the spirit of the present invention. Various changes and modifications are possible within the scope.

1 is a view showing a schematic configuration of a chemical liquid applying apparatus according to the present invention;

FIG. 2 is a perspective view showing the configuration of the inkjet printing unit shown in FIG. 1; FIG.

3 is a plan view of the inkjet printing unit shown in FIG. 2;

4 is a view showing the configuration of the chemical liquid recovery device shown in FIG.

5 is a perspective view showing the configuration of a sensor unit for detecting the level of the chemical liquid shown in FIG.

6 is a cross-sectional view showing a part of the configuration of the sensor shown in FIG.

7 is a conceptual diagram for improving a sensing capability of a sensor for sensing capacitance according to the present invention; And

FIG. 8 is a plan view illustrating some components of the sensor unit illustrated in FIG. 6.

Description of the Related Art [0002]

100: chemical liquid applying apparatus 110: inkjet printing unit

200: head assembly 210: inkjet head

132: purge tank 180: chemical liquid recovery device

182: leveling piping 186: chemical liquid recovery tank

192: capacitive sensor 194: metallic thin film

Claims (12)

In the chemical recovery device: A chemical liquid recovery tank for storing the waste liquid of the chemical liquid; A leveling pipe installed at the chemical liquid recovery tank and having a metallic thin film attached to one side in an up and down direction; And a plurality of sensors disposed on the other side of the leveling pipe so as to face the metallic thin film to increase the capacitance with the waste liquid accommodated in the leveling pipe by the thin film to detect the level of the waste liquid in the chemical liquid collection tank. A chemical liquid recovery device characterized by the above-mentioned. The method of claim 1, The chemical liquid recovery device; A guide in which the sensors are installed; And a control member installed in the guide to adjust the distance between the sensors and the thin film, or to adjust the vertical position of each of the sensors. The method of claim 2, The guide; And a through hole extending vertically opposite the longitudinal direction of the leveling pipe and extending in the longitudinal direction of the guide, wherein the sensors are inserted into the through hole. The method of claim 3, wherein The adjusting member is rotated to the left and right along the inner surface of the through hole to fix or separate each of the sensors to the guide device. The method according to claim 1 or 2, The thin film is chemical liquid recovery device, characterized in that attached to the positions for respectively measuring the level of the waste liquid level of the leveling pipe corresponding to the sensors. The method according to claim 1 or 2, The thin film is a chemical liquid recovery device characterized in that it is extended in the vertical direction between the positions for measuring the waste liquid level of the leveling pipe corresponding to the sensors. The method according to claim 1 or 2, Chemical sensors recovery device characterized in that the sensors are provided with capacitive sensors. In the chemical liquid applying device: A plurality of heads having a nozzle surface provided with a plurality of nozzles receiving the chemical liquid and discharging the chemical liquid to the upper surface of the object; A purge tank collecting the chemical liquid provided from the heads; A chemical liquid recovery tank for receiving and storing the chemical liquid from the purge tank; A leveling pipe installed at one side of the chemical liquid recovery tank; A metallic thin film attached to one side of the leveling pipe; And a plurality of capacitive sensors for sensing the level of the chemical liquid in the chemical liquid recovery tank by increasing the capacitance with the chemical liquid contained in the leveling pipe by the thin film. The method of claim 8, The chemical liquid applying apparatus; A guide in which the capacitive sensors are installed; And a control member installed in the guide to adjust the distance between the capacitive sensors and the thin film, or to adjust the vertical position of each of the sensors. The method of claim 9, The guide; And a through hole extending vertically opposite to the longitudinal direction of the leveling pipe and extending in the longitudinal direction of the guide, wherein the capacitive sensors are inserted into the through hole. 11. The method of claim 10, The adjusting member is; Rotating from side to side along the inner surface of the through hole to fix or separate each of the sensors to the guide device. The method according to any one of claims 8 to 11, The purge tank; A plurality of blades provided at an upper portion corresponding to the heads spaced apart and in parallel with the nozzle face of each of the heads and removing the chemical liquid remaining on the nozzle face in a non-contact manner with the nozzle face; And collecting and storing the chemical liquid removed by the blade.

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