FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See section 10, rule 13) “ELECTRODE DRYING DEVICE AND ELECTRODE DRYING METHOD” LG ENERGY SOLUTION, LTD., of Tower 1, 108, Yeouidaero, Yeongdeungpo-gu, Seoul 07335, Republic of Korea The following specification particularly describes the invention and the manner in which it is to be performed. 2 【Description】 【Title of the Invention】 ELECTRODE DRYING DEVICE AND ELECTRODE DRYING METHOD 【Technical Field】 5 This application claims the benefit of priority based on Korean Patent Application No. 10- 2020-0116020, filed on September 10, 2020, and the entire contents of the Korean patent application are incorporated herein by reference. The present invention relates to an electrode drying apparatus and an electrode drying method, and more particularly, to an electrode drying automatic control system and an electrode 10 drying automatic control method by measuring a gray level value. 【Background Art】 Recently, secondary batteries capable of charging and discharging have been widely used as energy sources of wireless mobile devices. In addition, the secondary battery has attracted attention as an energy source of an electric vehicle, a hybrid electric vehicle, etc., which are 15 proposed as a solution for air pollution of existing gasoline vehicles and diesel vehicles using fossil fuel. Therefore, the types of applications using the secondary battery are currently much diversified due to the advantages of the secondary battery, and it is expected that the secondary battery will be applied to many fields and products in the future. Such secondary batteries may be classified into lithium ion batteries, lithium ion polymer 20 batteries, lithium polymer batteries, etc., depending on the composition of the electrode and the 3 electrolyte, and among them, the amount of use of lithium-ion polymer batteries that are less likely to leak electrolyte and are easy to manufacture is on the increase. In general, secondary batteries are classified into cylindrical batteries and prismatic batteries in which an electrode assembly is embedded in a cylindrical or rectangular metal can, depending on the shape of a battery case, and 5 pouch-type batteries in which the electrode assembly is embedded in a pouch-type case of an aluminum laminate sheet. The electrode assembly built into the battery case is composed of a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and is a power generating element capable of charging and discharging. The electrode assembly is classified into a jelly-roll type wound with a separator interposed 10 between the positive electrode and the negative electrode which are long sheet-shaped and are coated with active materials, and a stack type in which a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked while a separator is interposed therebetween. The positive electrode and the negative electrode are formed by applying a positive 15 electrode slurry containing a positive electrode active material and a negative electrode slurry containing a negative electrode active material to a positive electrode current collector and a negative electrode current collector, to thereby form a positive electrode active material layer and a negative electrode active material layer, respectively, followed by drying and rolling them. At this time, the quality of the electrode is determined according to the drying conditions. 20 If the amount of drying heat is excessive, a significant amount of the binder in the electrode slurry moves to the surface during the drying process, thereby reducing the adhesive force of the electrode. If the amount of drying heat is low, the solvent remains in the electrode, causing roll 4 contamination in the coating and rolling process. In addition, in a general electrode drying process, the amount of heat for drying the electrode is supplied by hot air and infrared heaters. Herein, even under the same drying conditions, a change in drying quality occurs depending on the internal and external environment of the oven, 5 so a control system for checking the electrode quality in real time and automatically changing the drying conditions is required. In this regard, in the related art, there was no method in which a change in electrode quality such as electrode adhesive force could be checked in real time and the drying conditions of the electrode could be changed therefrom. For this reason, after the electrode production was 10 completed, the quality of the electrode was checked to determine whether it was defective, which caused the defect rate to rise. Therefore, it is necessary to develop a technology for real-time drying condition control of an electrode that can solve the above problems. 【Disclosure】 15 【Technical Problem】 The present invention was conceived to solve the above problems, and an object of the present invention is to provide an electrode drying apparatus and an electrode drying method capable of improving the quality of an electrode by checking the quality of an electrode in real time and adjusting the drying conditions of the electrode in real time accordingly. 20 【Technical Solution】 In one example, an apparatus for drying an electrode includes: an oven configured to 5 provide a space in which the electrode is dried and to include a hot air nozzle or an infrared heater; a color coordinate measuring unit configured to be positioned at an outlet of the oven and measure a color coordinate value of an electrode active material layer with respect to the dried electrode; and a controller configured to analyze a drying result of the electrode from the color coordinate 5 value, determine whether the electrode is defective in drying, and control a drying condition of the electrode. In one example, the color coordinate value may be L*. In another example, the color coordinate value is a gray value according to a gray scale. In one example, the color coordinate measuring unit includes a spectrophotometer or a 10 colorimeter. In a specific example, the controller analyzes a drying degree of the electrode or distribution of the binder in the electrode from the color coordinate value, and determines whether there is a defect in drying. In another example, the apparatus according to the present invention further includes an 15 outside air condition measuring unit configured to measure a temperature and humidity of the outside air. In a specific example, the controller may reset a drying condition by reflecting an existing drying condition and a temperature and humidity of the outside air when it is determined that the electrode is defective in drying. 20 In a specific example, the controller reflects the reset drying condition and changes the drying condition of the electrode in real time. In a specific example, the controller automatically updates the reset drying condition 6 through machine learning. Further, a method for drying an electrode according to the present invention includes: a step of manufacturing an electrode by forming an electrode active material layer including an electrode active material on a current collector, and putting the electrode in an oven of the above5 described apparatus to thereby dry the electrode; a step of measuring a color coordinate value of the electrode active material layer with respect to the dried electrode; a step of analyzing a drying result of the electrode from the color coordinate value, and determining whether the electrode is defective in drying; and a step of controlling the drying condition of the electrode. In one example, the color coordinate value may be L*. 10 In another example, the color coordinate value is a gray value according to a gray scale. In one example, the step of measuring the color coordinate value of the electrode active material layer may be performed through a spectrophotometer or a colorimeter. In another example, the step of measuring the color coordinate value of the electrode active material layer includes obtaining an image by photographing the surface of the electrode 15 through illumination and an image sensor, and converting the color information of the image into color coordinates. In one example, the step of analyzing the drying result of the electrode and determining whether the electrode is defective in drying includes a process of analyzing a drying degree of the electrode or distribution of the binder in the electrode from the color coordinate value, and 20 determining whether the electrode is defect in drying. In another example, the method according to the present invention further includes a step of measuring a temperature and humidity of the outside air. 7 In a specific example, the step of controlling the drying condition of the electrode includes a process of resetting the drying condition by reflecting an existing drying condition and a temperature and humidity of the outside air when it is determined that the electrode is defective in drying. 5 In a specific example, the step of controlling the drying condition of the electrode further includes a process of changing the drying condition of the electrode in real time by reflecting the reset drying condition. In a specific example, the step of controlling the drying condition of the electrode further includes a process of automatically updating the reset drying condition through machine learning. 10 【Advantageous Effects】 The present invention can improve the quality of the electrode by measuring the color coordinates of the electrode after drying to capture the electrode quality in real time, such as the adhesive force of the electrode or whether the electrode has been dried, and adjusting the drying conditions of the electrode in real time by reflecting this. 15 【Brief Description of the Drawings】 FIG. 1 is a block diagram showing the configuration of an electrode drying apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a process of measuring a color coordinate value of an electrode in the electrode drying apparatus according to the present invention. 20 FIG. 3 is a block diagram showing the configuration of an electrode drying apparatus according to another embodiment of the present invention. 8 FIG. 4 is a flowchart showing the procedure of an electrode drying method according to the present invention. 【Detailed Description of the Preferred Embodiments】 Hereinafter, the present invention will be described in detail with reference to the drawings. 5 The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may properly define the concept of the terms in order to best describe its invention. The terms and words should be construed as meaning and concept consistent with the technical idea of the present invention. In this application, it should be understood that terms such as "include" or "have" are 10 intended to indicate that there is a feature, number, step, operation, component, part, or a combination thereof described on the specification, and they do not exclude in advance the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof. Also, when a portion such as a layer, a film, an area, a plate, etc. is referred to as being "on" another portion, this includes not only the case where the 15 portion is "directly on" the another portion but also the case where further another portion is interposed therebetween. On the other hand, when a portion such as a layer, a film, an area, a plate, etc. is referred to as being "under" another portion, this includes not only the case where the portion is "directly under" the another portion but also the case where further another portion is interposed therebetween. In addition, to be disposed "on" in the present application may include the case 20 disposed at the bottom as well as the top. Hereinafter, the present invention will be described in detail with reference to the drawings. 9 FIG. 1 is a block diagram showing the configuration of an electrode drying apparatus according to an embodiment of the present invention. Referring to FIG. 1, an electrode drying apparatus 100 according to the present invention includes: an oven 120 configured to provide a space in which the electrode is dried and to include 5 a hot air nozzle or an infrared heater; a color coordinate measuring unit 130 configured to be positioned at an outlet of the oven 120 and measure a color coordinate value of an electrode active material layer with respect to the dried electrode; and a controller 140 configured to analyze a drying result of the electrode from the color coordinate value, determine whether the electrode is defective in drying, and control a drying condition of the electrode. 10 As described above, a change in drying quality occurs depending on the internal and external environment of the oven even under the same drying conditions. Conventionally, there was no way to check changes in electrode quality such as electrode adhesive force in real time and change the drying conditions of the electrode therefrom. For this reason, after the electrode production was completed, the quality of the electrode was checked to determine whether it was 15 defective, which caused the defect rate to rise. Therefore, the present invention can improve the quality of the electrode by measuring the color coordinates of the electrode after drying to capture the electrode quality in real time, such as the adhesive force of the electrode or whether the electrode has been dried, and adjusting the drying conditions of the electrode in real time by reflecting this. 20 Hereinafter, the configuration of the electrode drying apparatus according to the present invention will be described in detail. 10 FIG. 2 is a schematic diagram showing a process of measuring a color coordinate value of an electrode in the electrode drying apparatus according to the present invention. Referring to FIG. 2, an electrode drying apparatus 100 according to the present invention includes an oven 120. The oven 120 has a chamber shape and provides a space in which the 5 electrode 110 is dried. The electrode 110 to be dried is temporarily accommodated during the drying process, and internal heat may be prevented from escaping to the outside for drying. Meanwhile, the electrode 110 may have a structure in which an electrode active material layer is formed by applying an electrode slurry including an electrode active material on a current collector. The electrode slurry may be applied to at least one surface of the current collector. 10 Referring to FIG. 2, the current collector is wound around a separate unwinding roller 111 and then unwound therefrom. An electrode slurry is applied to at least one surface of the unwound current collector, and the electrode slurry may be applied by, for example, the slot die 112. The electrode 110 to which the electrode slurry is applied is put into the oven 120 and dried. In this case, the current collector may be a positive electrode current collector or a negative 15 electrode current collector, and the electrode active material may be a positive electrode active material or a negative electrode active material. In addition, the electrode slurry may further include a conductive material and a binder in addition to the electrode active material. In the present invention, the positive electrode collector generally has a thickness of 3 to 500 micrometers. The positive electrode current collector is not particularly limited as long as it 20 has high conductivity without causing a chemical change in the battery. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon or aluminum or stainless steel of which the surface has been treated with carbon, nickel, titanium, 11 silver, or the like. The current collector may have fine irregularities on the surface thereof to increase the adhesion of the positive electrode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible. The sheet for the negative electrode collector generally has a thickness of 3 to 500 5 micrometers. The negative electrode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and examples thereof include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel of which the surface has been treated with carbon, nickel, titanium, silver or the like, aluminum-cadmium alloy, or the like. In addition, like the positive electrode current collector, fine 10 unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric. In the present invention, the positive electrode active material is a material capable of causing an electrochemical reaction and a lithium transition metal oxide, and contains two or more 15 transition metals. Examples thereof include: layered compounds such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2) substituted with one or more transition metals; lithium manganese oxide substituted with one or more transition metals; lithium nickel oxide represented by the formula LiNi1-yMyO2 (wherein M = Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn or Ga and contains at least one of the above elements, 0.01 ≦ y ≦ 0.7); lithium nickel cobalt manganese composite 20 oxide represented by the formula Li1+zNibMncCo1-(b+c+d)MdO(2-e)Ae such as Li1+zNi1/3Co1/3Mn1/3O2, Li1+zNi0.4Mn0.4Co0.2O2 etc. (wherein -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2, 0≤e≤0.2, b+c+d<1, M = Al, Mg, Cr, Ti, Si or Y, and A = F, P or Cl); olivine-based lithium metal phosphate 12 represented by the formula Li1+xM1-yM'yPO4-zXz (wherein M = transition metal, preferably Fe, Mn, Co or Ni, M'= Al, Mg or Ti, X = F, S or N, and -0.5≤x≤0.5, 0≤y≤0.5, 0≤z≤0.1). Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; metal complex oxide such as LixFe2O3(0≤x≤1), LixWO2(0≤x≤1), 5 SnxMe1-xMe’yOz (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, groups 1, 2, and 3 of the periodic table, halogen; 0 10 Referring to FIG. 4, first, an electrode active material layer including an electrode active material is formed on a current collector to measure color coordinate values, thereby manufacturing an electrode. Details of the electrode are the same as described above. When electrode manufacturing is completed, the electrode is put into an oven and dried. In this case, the drying time and the drying heat amount may be determined by the specifications 15 of the electrode, for example, the loading amount of the electrode active material or the solvent content in the electrode slurry, the binder content in the electrode slurry, etc. The dried electrode is discharged out of the oven. 20 When drying of the electrode is completed, a color coordinate value is measured for the dried electrode. In this case, the color coordinate value of the electrode active material layer is measured by a color coordinate measuring unit according to the electrode drying apparatus as 23 described above. Since the color coordinate measuring unit is located near the outlet of the oven, the color coordinate value can be measured directly with respect to the electrode discharged from the oven. As described above, the color coordinate value of the electrode may be a color coordinate value measured at a certain point of a certain electrode active material layer, and after selecting 5 several measurement points in the electrode active material layer, the average value of the color coordinate values measured at the measurement points may be used as the color coordinate value. The present invention installs only a simple device capable of measuring color coordinates near the outlet of the oven and quantifies the dry state of the electrode through color coordinate measurement, thereby simplifying the measuring method and reducing the time and cost required 10 for evaluation. Meanwhile, in a specific example of the present invention, the electrode may not be rolled. That is, the present invention does not evaluate the electrode that has passed through the rolling process, but by performing the evaluation on the electrode that has not undergone the rolling process, it is possible to filter out defective electrodes before the rolling process and significantly 15 reduce the defect rate after the rolling process. This can prevent contamination of the rolling roll, etc. due to residual solvent in the electrode in the rolling process. However, the present invention is not limited thereto, and color coordinates may be measured at any stage after drying the electrode. In one example, the color coordinate value may be L*. As described above, L* is a value related to the measured lightness of the object and may be displayed from 0 to 100. 20 In another example, the color coordinate value may be a gray value according to a gray scale. That is, an image of the dry surface of the electrode may be converted into a gray scale capable of confirming only the contrast, and a gray value may be measured therefrom to determine 24 whether the electrode is dried. As described above, in the present invention, the color coordinates that can uniformly measure the contrast of the electrode surface are used, and the drying quality can be determined by quantitatively measuring the contrast of the surface of the electrode active material layer. 5 In one example, the step of measuring the color coordinate value of the electrode active material layer may be performed through a spectrophotometer or a colorimeter. In this case, a color coordinate value may be directly measured on the surface of the electrode active material layer. In another example, the step of measuring the color coordinate value of the electrode active material layer may include obtaining an image by photographing the surface of the electrode 10 through illumination and an image sensor, and converting the color information of the image into color coordinates. In this case, a camera may be used as the image sensor. When an image is obtained, it is converted into a color coordinate system to be measured, and a color coordinate value is measured. For example, after converting an image photographed through a camera into a gray scale, the gray value or L* value of the corresponding image may be measured. 15 As described above, the color coordinate value may be measured using a colorimeter directly with respect to the electrode, but the color coordinate value may be indirectly measured using an image obtained by photographing the surface of the electrode active material layer. 20 When the color coordinate value is measured, it is determined from this whether the electrode is defective in drying. Specifically, the process of analyzing a drying degree of the electrode or distribution of the binder in the electrode from the color coordinate value, and 25 determining whether there is a defect in drying may be performed. Specifically, the adhesive force of the electrode active material layer according to drying of the electrode may be evaluated through analysis of the distribution of the binder in the electrode, and the degree of drying and whether the drying of the electrode has been completed may be evaluated through color coordinate values. 5 In this case, when the color coordinate value is smaller than the preset value, it may be determined that the drying quality of the electrode is poor. The preset value may be selected from color coordinate values of the electrodes determined to be good by measuring drying quality of a plurality of electrodes. For example, the preset value may be derived from a profile of a color coordinate value according to an adhesive force of an electrode or a solvent content in the electrode. 10 To this end, color coordinate values for a plurality of electrode samples are measured, and adhesive force and solvent content in the electrode are measured accordingly, to thereby be formed as a database. Thereafter, a color coordinate value capable of satisfying both the criteria of the adhesive force of the electrode active material layer and the content of the solvent in the electrode may be derived. 15 Meanwhile, the electrode drying method according to the present invention may further include measuring the temperature and humidity of the outside air. Here, the outside air means the air outside the oven. In the drying process of the electrode, even when the same drying conditions are applied, the drying quality is changed according to the internal and external environment of the oven, so the present invention can measure the temperature and humidity of the outside air and 20 reflect this in the drying process. 26 In the present invention, the step of controlling the drying condition of the electrode includes a process of resetting the drying condition by reflecting an existing drying condition and a temperature and humidity of the outside air when it is determined that the electrode is defective in drying. In this case, the previously measured color coordinate value may be reflected in resetting 5 the drying condition. There are various drying conditions that are reset at this time, and for example, the transfer speed of the electrode, the temperature of the hot air sprayed from the hot air nozzle, the flow rate of the hot air, and the output of the infrared heater can be adjusted. In addition, when a screen for blocking infrared rays and hot air is installed between the infrared heater or the hot air nozzle, the 10 area in which the electrode is exposed to the hot air or infrared rays may be controlled by adjusting the position of the screen or the number of screens. In addition, controlling the drying condition of the electrode further includes a process of changing the drying condition of the electrode in real time by reflecting the reset drying condition. Through this, the defective rate of the electrode can be reduced and the quality of the electrode can 15 be improved. In addition, controlling the drying condition of the electrode further includes a process of automatically updating the reset drying condition through machine learning. Through this, drying conditions can be established according to specifications of electrodes to be manufactured and conditions of outside air, and drying conditions can be automatically selected and adjusted during 20 production of the corresponding electrodes in the future. In this case, for example, the machine learning may be performed through a method such as deep learning. Learning data may be constructed from a plurality of data obtained while 27 measuring the drying quality of a plurality of electrodes, and drying conditions according to specifications of electrodes to be manufactured and conditions of outside air may be learned from this. This can later be reflected in the evaluation of the drying quality of other electrodes. Likewise, the present invention can improve the quality of the electrode by measuring the 5 color coordinates of the electrode after drying to evaluate the electrode drying quality in real time, such as the adhesive force of the electrode or whether the electrode has been dried, adjusting the drying conditions of the electrode in real time by reflecting this, and then reflecting the adjustment in the electrode quality evaluation again. 10 The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the drawings disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical 15 idea of the present invention is not limited by these drawings. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention. On the other hand, in this specification, terms indicating directions such as up, down, left, right, before, and after are used, but it is obvious that these terms are for convenience of description 20 only and may change depending on the location of the object or the location of the observer. [Description of reference numerals] 28 100, 200: electrode drying apparatus 110: electrode 111: unwinding roller 112: slot die 5 120: oven 130: color coordinate measuring unit 140: controller 150: outside air condition measuring unit 29 WE CLAIM: 【Claim 1】 An apparatus for drying an electrode, comprising: an oven configured to provide a space in which the electrode is dried and to include a 5 hot air nozzle or an infrared heater; a color coordinate measuring unit configured to be positioned at an outlet of the oven and to measure a color coordinate value of an electrode active material layer of the dried electrode; and a controller configured to analyze a drying result of the dried electrode from the color 10 coordinate value, to determine whether the dried electrode is defective in drying, and to control a drying condition. 【Claim 2】 The apparatus of claim 1, wherein the color coordinate value is L*. 15 【Claim 3】 The apparatus of claim 1, wherein the color coordinate value is a gray value according to a gray scale. 20 【Claim 4】 30 The apparatus of claim 1, wherein the color coordinate measuring unit includes a spectrophotometer or a colorimeter. 【Claim 5】 5 The apparatus of claim 1, wherein the color coordinate measuring unit includes an image sensor capable of taking an image of a surface of the electrode active material layer. 【Claim 6】 The apparatus of claim 1, wherein the controller is further configured to analyze a drying 10 degree of the dried electrode or distribution of the binder in the dried electrode from the color coordinate value, and to determine whether there is a defect in drying. 【Claim 7】 The apparatus of claim 1, further comprising: an outside air condition measuring unit 15 configured to measure a temperature and humidity of the outside air. 【Claim 8】 The apparatus of claim 1, wherein the controller is further configured to reset the drying condition by reflecting an existing drying condition and a temperature and humidity of the 20 outside air when it is determined that the dried electrode is defective in drying. 31 【Claim 9】 The apparatus of claim 8, wherein the controller is further configured to reflect the reset drying condition and to change the drying condition in real time. 5 【Claim 10】 The apparatus of claim 8, wherein the controller is further configured to automatically update the reset drying condition through machine learning. 10 【Claim 11】 A method for drying an electrode using the apparatus according to claim 1, comprising: manufacturing the electrode by forming the electrode active material layer including an electrode active material on a current collector, and putting the electrode in the oven of the apparatus to thereby dry the electrode; 15 measuring the color coordinate value of the electrode active material layer ; analyzing the drying result of the dried electrode from the color coordinate value, and determining, whether the dried electrode is defective in drying; and controlling the drying condition. 20 【Claim 12】 32 The method of claim 11, wherein the color coordinate value is L*. 【Claim 13】 The method of claim 11, wherein the color coordinate value is a gray value according to 5 a gray scale. 【Claim 14】 The method of claim 11, wherein the measuring of the color coordinate value of the electrode active material layer is performed through a spectrophotometer or a colorimeter. 10 【Claim 15】 The method of claim 11, wherein the measuring of the color coordinate value of the electrode active material layer includes obtaining, an image by photographing a surface of the dried electrode through illumination and an image sensor , and converting color information of 15 the image into color coordinates. 【Claim 16】 The method of claim 11, wherein the analyzing of the drying result of the electrode and determining whether the electrode is defective in drying includes analyzing, a drying degree of 20 the dried electrode or distribution of the binder in the dried electrode from the color coordinate 33 value, and determining whether the dried electrode is defect in drying. 【Claim 17】 The method of claim 11, further comprising: measuring a temperature and humidity of 5 the outside air. 【Claim 18】 The method of claim 11, wherein the controlling of the drying condition of the electrode includes resetting the drying condition by reflecting an existing drying condition and a 10 temperature and humidity of the outside air when it is determined that the dried electrode is defective in drying 【Claim 19】 The method of claim 18, wherein the controlling of the drying condition further includes 15 changing, the drying condition in real time by reflecting the reset drying condition. 【Claim 20】 The method of claim 18, wherein the controlling of the drying condition further includes automatically updating the reset drying condition through machine learning.