JP2022158397A - Coating method - Google Patents

Abstract

To provide a coating technique effective to form a projecting and recessed decorative pattern on an object to be coated.SOLUTION: A coating method according to the embodiment includes: a first step S101 of forming a base coating film on a surface of a to-be-coated object; a second step S102 of drying the base coating film formed in the first step S101 and fixing it to the to-be-coated object; and a third step S103 of jetting paint only from a selection nozzle selected from a plurality of nozzles of an ink jet head to form a projecting and recessed decorative pattern on a surface of the base coating film fixed in the second step S102.SELECTED DRAWING: Figure 2

Description

The present invention relates to a coating method.

Patent Document 1 below discloses a rotary atomizing head type coating apparatus used for coating an object to be coated such as an automobile body. When this coating apparatus is used, paint is supplied to the rotary atomizing head while the rotary atomizing head is rotated at a high speed with a high voltage applied. As a result, the paint is centrifugally atomized by the rotary atomizing head into charged paint particles having a certain particle size range, and sprayed onto the object to be coated by the shaping air that is blown toward the object to be coated. At this time, due to the so-called "leveling" effect, which is the property that the coating granules flow to form a flat and smooth coating film, the film is laminated on the object to be coated with a substantially constant film thickness. As a result, it becomes possible to ensure rust prevention, weather resistance and high appearance of the object to be coated.

JP-A-11-262696

By the way, there is known a decorating technique in which a decorating film that has been patterned or processed in advance in an uneven shape is attached in order to decorate an object to be coated. This decorating technique is disadvantageous in that the cost is high due to the use of expensive decorating films. Therefore, as a new technology to replace this decorating technology, there is a demand for a coating technology for decorating an object to be coated at low cost by using a paint that is cheaper than the decorating film.

When the coating apparatus disclosed in Patent Document 1 is used in response to such a request, the paint is sprayed irregularly over a wide range of the object to be coated with a large variation in the average particle size of the paint, so the layer height of the paint It is difficult to partially control the thickness and form an uneven decorative pattern. Further, it is known that paints used for coating the bodies of automobiles generally have high smoothness to the bodies to be coated. For this reason, even if the paint can be sprayed on the surface of the body so that the layered height partially changes, the film thickness will change so as to be approximately constant due to the action of the subsequent leveling of the paint. A problem may occur that the uneven pattern cannot be formed.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object thereof is to provide a coating technique that is effective for forming an uneven decorative pattern on an object to be coated.

One aspect of the present invention is
a base coating step of forming a base coating film on the surface of the object to be coated;
a fixing step of fixing the base coating film formed in the base coating step to the surface of the object to be coated by drying;
An inkjet head in which a plurality of nozzles are regularly arranged is arranged on the object to be coated, and the paint is ejected only from selected nozzles selected from the plurality of nozzles of the inkjet head and fixed in the fixing step. a decorative coating step of forming an uneven decorative pattern on the surface of the base coating film;
a painting method,
It is in.

In the coating method of the above aspect, the base coating film is formed on the surface of the object to be coated in the base coating step. After that, the base coating formed in the base coating step is dried in the fixing step. Thereby, the base coating film can be fixed on the surface of the object to be coated. In the decorative coating step, after the fixing step, the coating material is sprayed toward the base coating film only from selected nozzles selected from the plurality of nozzles of the inkjet head. According to this decorative coating step, the film thickness of the decorative coating layer laminated on the surface of the base coating film can be made different between the portion corresponding to the selected nozzle and the portion corresponding to other than the selected nozzle. As a result, a part where the coating film is laminated and a part where the coating film is not laminated or the lamination height is relatively low are formed on the surface of the base coating film, and the film thickness difference between these parts is used. can form an uneven decorative pattern.

Here, the base coating film on the surface of the object to be coated is formed by the coating material forming a film, and suppresses the fluidization and smoothing of the newly sprayed coating particles on the surface. function. For this reason, it is possible to suppress the progress of leveling of the coating particles after increasing the thickness of only the portion of the base coating film to which the coating material has been sprayed from the selected nozzle. As a result, it is possible to maintain the state in which the surface of the base coating film has a desired uneven shape. As a result, it is possible to form a desired concave-convex decorative pattern on the object to be coated using a paint that is cheaper than the decorative film.

As described above, according to the above aspect, it is possible to provide a coating technique that is effective for forming an uneven decorative pattern on an object to be coated.

FIG. 4 is a diagram showing how the body of an automobile is decoratively coated using the coating method of the first embodiment; 4 is a flowchart of a coating method according to the first embodiment; FIG. 3 is a flowchart of decoration processing in FIG. 2; FIG. 4 is a plan view schematically showing how the nozzle is used when forming a base coating film on the surface of an object to be coated in the coating method of Embodiment 1; FIG. 2 is a cross-sectional view schematically showing how a base coating film is formed on the surface of an object to be coated in the coating method of Embodiment 1; FIG. 4 is a cross-sectional view schematically showing how a decorative coating film is formed on the surface of a base coating film in the coating method of Embodiment 1; 4 is a plan view schematically showing how the nozzle is used when forming a decorative coating film on the surface of the base coating film in the coating method of Embodiment 1. FIG. 4 is a plan view schematically showing how a decorative coating film is formed on the surface of a base coating film in the coating method of Embodiment 1. FIG. 4 is a flowchart corresponding to the decorating process of FIG. 3 regarding the coating method of the second embodiment.

Preferred embodiments of the above aspects will now be described.

In the coating method of the above aspect, in the decorating coating step, the jetting process of jetting the paint from the selected nozzle onto the surface of the base coating film is repeated a plurality of times based on the predetermined film thickness of the decorative pattern. is preferred.

According to this coating method, the coating material is repeatedly sprayed from the selected nozzle a plurality of times to stepwise increase the film thickness of the coating film laminated on the surface of the base coating film, thereby forming the decorative pattern into a desired concave-convex shape. can be done.

In the coating method of the aspect described above, it is preferable that in the decorative coating step, the injection process is repeated a plurality of times using the same selected nozzle.

According to this coating method, it is possible to simplify the process of forming a decorative pattern by repeatedly injecting paint from the same selected nozzle a plurality of times.

In the coating method of the aspect described above, it is preferable that in the base coating step, the base coating film is formed by spraying paint from the plurality of nozzles of the inkjet head.

According to this coating method, the same inkjet head is used for both the base coating step and the decorative coating step, so that the cost required for forming the decorative pattern on the object to be coated can be kept low.

In the coating method of the above aspect, it is preferable that at least one of the diameter of the droplets of the paint ejected from the plurality of nozzles and the number of droplets per ejection is set individually.

According to this coating method, the diameter of the droplets of the paint from the plurality of nozzles and the number of droplets per injection are individually set, so that the decoration laminated on the surface of the base coating film in the decoration coating step It becomes possible to finely adjust the film thickness of the coating film for each portion corresponding to each selected nozzle. This makes it possible to increase the variety of types of decorative patterns.

(Embodiment 1)
Hereinafter, the coating method of Embodiment 1 will be described with reference to the drawings.

In the drawings referred to in the description of this specification, unless otherwise specified, the first direction along the surface of the object to be coated is indicated by an arrow X, and the direction along the surface of the object to be coated and the first direction Let arrow Y denote a second direction perpendicular to the direction, and arrow Z denote a third direction perpendicular to both the first and second directions.

As shown in FIG. 1, the coating method of Embodiment 1 uses an inkjet head 10 to apply a decorative coating to a surface Wa of a workpiece W to be coated. In the first embodiment, a case where decorative coating is applied to a steel plate constituting a body of an automobile as an object W to be coated is exemplified.

The ink jet head 10 has a plurality of nozzles 11 each of which opens toward the object W to be coated. It is configured to be able to jet toward the surface Wa of the object W to be coated. The inkjet head 10 is preferably configured to continuously flow the paint P between an internal reservoir 12 and an external reservoir (not shown). According to this configuration, when the paint P has a higher viscosity than paint generally used for painting wooden materials, etc., the paint P stays in the reservoir 12 and prevents the paint P from being ejected from each nozzle 11. can be suppressed. This inkjet head 10 is attached to a robot arm 21 of a coating robot 20 .

Regarding the structure of the inkjet head 10, a first head structure configured such that the nozzle diameters of the plurality of nozzles 11 are the same, and a second head structure configured such that the nozzle diameters of the plurality of nozzles 11 are individually determined. 2 head structure can be employed as appropriate.

By adopting the first head structure, it is possible to jet the coating material P from the plurality of nozzles 11 with a substantially constant droplet diameter by controlling the number of times of jetting and the amplitude of the jetting mechanism. The droplet diameter of the paint P can be controlled in a state in which variations are suppressed so that the error is generally constant within a range of, for example, about 30 to 80 μm, with an error of about several μm. On the other hand, if the second head structure is adopted, the diameter of droplets of the paint P ejected from the plurality of nozzles 11 can be individually set and used. On the other hand, when a rotary atomizing head type coating apparatus is used, the droplet diameters are generally distributed randomly over a wide range of, for example, several μm to 150 μm. is unfavorable for forming

As a more specific structure of the inkjet head 10, for example, the structure of the inkjet head disclosed in JP-A-2016-30332, JP-A-2016-30388, etc. can be adopted. In this case, the inkjet head 10 has an on-demand structure (for example, an electro-mechanical conversion method that ejects droplets of the paint P using deformation of a piezoelectric diaphragm, and a paint P that uses the generation of air bubbles due to heat). an electro-thermal conversion method for ejecting droplets, an electrostatic attraction method for ejecting droplets of paint P by electrostatic attraction, etc.) can be used as appropriate.

In the object to be coated W constituting an automobile, examples of the surface Wa to be decoratively coated include an electrodeposition coated surface, an intermediate coated surface, and a clear coated surface. That is, three types of painted surfaces are assumed as decorative painted surfaces. At this time, the electrodeposition coated surface as the decorative coated surface has a surface tension in the range of 30 to 50 N/m and a surface roughness (surface roughness Ra defined in JIS B 0601) of 0.5. It is preferably in the range of 2 to 0.5. It is preferable that the intermediate coated surface as the decorative coated surface has a surface tension in the range of 25 to 35 N/m and a surface roughness in the range of 0.1 to 0.3. The clear coated surface as the decorative coated surface preferably has a surface tension in the range of 20 to 30 N/m and a surface roughness in the range of 0.01 to 0.15. In summary, such a decorative coated surface has a surface tension range of 20 to 50 N/m and a surface roughness range of 0.01 to 0.5, so it looks like a decorative building board. It is difficult to form a decorative pattern of a desired shape because droplets of the paint P are more likely to flow than a wooden material. Therefore, in this embodiment, a coating method, which will be described later, is adopted.

Further, it is preferable to use a water-based or solvent-based paint P having a viscosity in the range of 25 to 110 cps and a surface tension in the range of 10 to 35 N/m. A metallic pigment may be added to the paint P as required.

Specifically, it is preferable to use paints containing amino-acrylic resins, amino-alkyd resins, amino-polyester resins, polyisocyanate-acrylic resins, etc. as vehicle components. The form of these paints is not particularly limited, and any form such as organic solvent type, non-aqueous dispersion type, aqueous solution type, and powder type can be used. When the base coat paint contains metallic pigments such as aluminum flakes and mica flakes, organic coloring pigments and inorganic coloring pigments may be added as necessary.

The control panel 30 incorporates a first control section 31 electrically connected to the inkjet head 10 and a second control section 32 electrically connected to the coating robot 20 .

The first controller 31 has a function of controlling the inkjet head 10 . Specifically, the first control unit 31 individually controls each of the plurality of nozzles 11 of the inkjet head 10, selects the selected nozzle 11A to be used from among the plurality of nozzles 11, and jets from the selected nozzle 11A. The injection condition of the paint P to be applied is read.

The ejection conditions typically include control parameters for directly or indirectly controlling the number of ejections per unit time of each selected nozzle 11A, the number of droplets per unit number of ejections of each selected nozzle 11A, and the like. be done.

The second control section 32 has a function of controlling the painting robot 20 . Specifically, the trajectory and attitude of the tip of the robot arm 21 are controlled by the second controller 32 .

When the inkjet head 10 is used, when the surface Wa of the object W to be coated includes a curved surface, the object W to be coated is adjusted so that the distance d between the surface Wa and the inkjet head 10 is about 3 to 30 mm. It is preferable that the ink jet head 10 is set in a close state. Incidentally, when the surface Wa of the object W to be coated is composed only of flat surfaces, the distance d can also be set to about 5 to 15 mm. This distance d is much smaller than the distance (for example, 200-300 mm) from the rotary atomizing head to the surface Wa of the workpiece W when using a known rotary atomizing head coating apparatus. In this case, the coating robot 20 can be controlled by the second control unit 32 to perform coating while keeping the distance d small.

Therefore, compared with the case of using a known rotary atomizing head type coating apparatus, the amount of paint P scattered (that is, dust) generated during coating can be reduced. As a result, it is possible to use a simple painting booth with low initial equipment costs and low energy costs, and to omit curing such as masking for painting.

The data reading device 40 has a function of reading and storing image data relating to a desired decorative pattern. This data reader 40 is electrically connected to the first controller 31 to control the inkjet head 10 based on the image data.

Next, the coating method of Embodiment 1 will be specifically described with reference to FIGS. 2 to 8. FIG.

As shown in FIG. 2, the painting method of the first embodiment is achieved by sequentially executing at least the process shown in step S101 through the process shown in step S103. It should be noted that other steps may be added to these steps, or at least one of these steps may be divided into multiple steps, as required.

The first step S101 in FIG. 2 is a base coating step for forming the base coating film 1 on the surface Wa of the object W to be coated. In the first step S101, the coating robot 20 is controlled to arrange the inkjet head 10 so that the plurality of nozzles 11 face the surface Wa of the object W to be coated, and stop at that position. After that, the paint P is jetted from all of the plurality of nozzles 11 provided in the inkjet head 10 based on predetermined conditions.

As shown in FIG. 4, one surface of the inkjet head 10 has a plurality of nozzles 11 regularly arranged in a two-dimensional rectangular grid. The nozzle centers of the plurality of nozzles 11 are arranged on intersections of a plurality of virtual straight lines La extending in the first direction X and a plurality of virtual straight lines Lb extending in the second direction Y. As shown in FIG. At this time, the two virtual straight lines La and Lb are orthogonal to each other. Then, in the first step S101, all of the plurality of nozzles 11 are set to the ON state, which is the state of use.

Regarding the arrangement of the plurality of nozzles 11, the interval Da between the two adjacent virtual straight lines La and the interval Db between the two adjacent virtual straight lines Lb may be the same size, or the interval Da and the interval Db may be the same. may be of different dimensions. Also, a lattice arrangement or a zigzag arrangement in which the virtual straight line Lb obliquely intersects the virtual straight line La may be employed.

As shown in FIG. 5(a), the coating particles Pa having a substantially constant droplet diameter ejected from each nozzle 11 adhere to the surface Wa of the object W to be coated in the first step S101. Thereafter, as shown in FIG. 5(b), each coating particle Pa flows along the surface Wa of the object W to be coated by leveling action to form a base coating film 1 on the surface Wa of the object W to be coated. .

The second step S102 in FIG. 2 is a fixing step for fixing the base coating film 1 formed in the first step S101 to the surface Wa of the object W to be coated. At this time, the automobile body is carried into a drying booth, and the base coating film 1 is dried based on predetermined drying conditions (drying temperature and drying time). According to the second step S102, water contained in the paint P of the base coating film 1 is removed by drying, and the base coating film 1 is fixed on the surface Wa of the object W to be coated as a solid layer. In order to shorten the drying time, it is preferable to select a temperature within a low temperature range that is above the room temperature range and below the high temperature range of 100° C. or higher as the drying temperature. It is also possible to carry out the drying process in the normal temperature range depending on the influence of the external environment or by extending the drying time.

It should be noted that this second step S102 is preferably performed before leveling the base coating film 1 to a completely flat state. For this reason, the drying in the second step S102 is carried out so that the paint P can be fixed to the surface 1a of the base coating film 1 in a leveling-suppressed state (that is, in a state in which the surface tension of the paint grains Pa is controlled) in step S106, which will be described later. It is preferable to set conditions. As a result, a relatively large concave-convex shape effective for fixing the paint P can be left on the surface 1a of the base coating film 1 while suppressing leveling on the surface 1a of the base coating film 1. - 特許庁

In the third step S103 in FIG. 2, after the second step S102, the paint P is jetted only from the selected nozzle 11A selected from among the plurality of nozzles 11 of the inkjet head 10, and the paint P is sprayed onto the surface 1a of the base coating film 1. This is the decorative painting step for forming the concave-convex decorative pattern 2 . This third step S103 is achieved by sequentially executing the processes from step S104 to step S108, as shown in FIG.

Step S<b>104 in FIG. 3 is a step of setting the selected nozzle 11</b>A from among the plurality of nozzles 11 . According to this step S104, as shown in FIG. 6, each of the plurality of nozzles 11 is divided into a selected nozzle 11A (see solid line in FIG. 6) and a non-selected nozzle 11B (see two-dot chain line in FIG. 6). ). Then, the selected nozzle 11A is set to the ON state in which the paint P is ejected, and the non-selected nozzle 11B is set to the OFF state in which the paint P is not ejected.

Step S105 in FIG. 3 is a step of reading the aforementioned ejection conditions for each selected nozzle 11A. The ejection conditions at this time are preferably determined by the first control unit 31 based on image data (for example, three-dimensional data of decorative patterns) transmitted from the data reading device 40 . Then, this injection condition is temporarily stored in the first control unit 31 .

Step S106 in FIG. 3 is a step of controlling the selected nozzle 11A according to the ejection conditions read in step S105 and ejecting the paint P onto the surface 1a of the base coating film 1 from the selected nozzle 11A. According to this step S106, the surface 1a of the base coating film 1 can be partially uneven by the coating material P. As shown in FIG.

Step S107 in FIG. 3 is a step for determining whether or not to continue decorative coating after step S106 based on the injection conditions read in step S105. That is, when it is predicted that the film thickness of the decorative coating film will not reach the predetermined film thickness of the decorative pattern 2, it is determined that the decorative coating should be continued. On the other hand, when it is predicted that the film thickness of the decorative coating film will reach the predetermined film thickness of the decorative pattern 2, it is determined not to continue the decorative coating. According to this step S107, if the decorative coating is to be continued ("Yes" in step S107), the process proceeds to step S108. Otherwise ("No" in step S107), the decorative coating process ends. do.

Step S108 in FIG. 3 is a step for determining whether or not to change the selected nozzle 11A after step S107. According to this step S108, if the selected nozzle 11A is to be changed ("Yes" in step S108), the process returns to step S104, and the selected nozzle 11A is reset from among the plurality of nozzles 11. FIG. On the other hand, if the selected nozzle 11A is not changed ("No" in step S108), the process returns to step S106, and the paint P is sprayed onto the surface 1a of the base coating film 1 from the same selected nozzle 11A.

7 and 8 illustrate the jetting process of jetting the coating material P from the selective nozzle 11A onto the surface 1a of the base coating film 1. FIG. For convenience of explanation, this injection process simulates a case where the number of droplets per injection is one for each selected nozzle 11A.

As shown in FIGS. 7( a ) and 8 ( a ), the coating during the second injection from above the coating particles Pa adhering to the surface 1 a of the base coating film 1 during the first injection from the selection nozzle 11A Particles Pa are stacked in the thickness direction, which is the third direction Z. As shown in FIG. As a result, the coating material P can be applied to a portion of the surface 1a of the base coating film 1 in two layers. By increasing the number of repetitions of the ejection process by the selection nozzle 11A, the stacking height of the coating particles Pa in the third direction Z can be increased.

The number of repetitions of the ejection process by the selected nozzle 11A is not particularly limited, and can be appropriately selected based on the ejection conditions read in step S105. Alternatively, the injection process by the selected nozzle 11A may be executed a fixed number of times set in advance.

As shown in FIGS. 7(b) and 8(b), thereafter, part of the coating particles Pa adhering to the surface 1a of the base coating film 1 is fluidized to form an uneven decorative pattern 2. . In this decorative pattern 2, the portion corresponding to the selected nozzle 11A is the convex portion 2a, and the portion corresponding to the nozzle other than the selected nozzle 11A is the concave portion 2b. At this time, since the base coating film 1 is formed in advance on the surface Wa of the object to be coated W in the first step S101 in FIG. ) and compatibility can be suppressed. As a result, the desired uneven shape of the decorative pattern 2 can be maintained.

After completing the third step S103 in FIG. 2, a clear topcoat paint can be applied to the surface Wa of the object to be coated W including the decorative pattern 2, if necessary. The coating at this time is performed using a known rotary atomizing head type coating apparatus (not shown), and baking is performed after coating. This baking process is performed at a higher temperature and for a longer time than the drying process in step S102.

When using a clear top coat paint, specifically, amino-acrylic resin, amino-alkyd resin, acrylic resin, amino oil-free alkyd resin, silicon polyester resin, fluorine resin, organic solvent diluted type such as urethane resin Paint can be used.

The effects of the first embodiment described above will be described below.

In the coating method of Embodiment 1, the base coating film 1 is formed on the surface Wa of the object W to be coated in the first step S101. After that, the base coating film 1 formed in the first step S101 is dried in the second step S102. Thereby, the base coating film 1 can be fixed on the surface Wa of the object W to be coated. In the third step S103, after the second step S102, the paint P is jetted toward the base coating film 1 only from the selected nozzle 11A selected from among the plurality of nozzles 11 of the inkjet head . According to the third step S103, the film thickness of the decorative coating layer laminated on the surface 1a of the base coating film 1 can be made different between the portion corresponding to the selection nozzle 11A and the portion corresponding to the nozzles other than the selection nozzle 11A. can. As a result, a portion where the decorative coating film is laminated on the surface 1a of the base coating film 1 and a portion where the decorative coating film is laminated or where the lamination height is relatively low are formed. The uneven decorative pattern 2 can be formed by using the difference.

Here, the base coating film 1 on the surface Wa of the object W to be coated is formed by forming the coating material P into a film, and the coating particles Pa newly sprayed onto the surface 1a flow to smooth the surface. It exerts the function of suppressing the decomposition. For this reason, it is possible to suppress the progress of leveling of the coating particles Pa after increasing the film thickness of only the portion of the base coating film 1 to which the coating material P is sprayed from the selection nozzle 11A. As a result, the surface 1a of the base coating film 1 can be maintained in a desired irregular shape. As a result, it is possible to form the desired concave-convex decorative pattern 2 on the object to be coated W using the paint P which is cheaper than the decorative film.

Further, by using the same inkjet head 10 for both the first step S101 and the third step S103, it is possible to reduce the cost required to form the decorative pattern 2 on the object W to be coated. Moreover, by using the same paint P in the first step S101 and the third painting step S103, the boundary between the base paint film 1 and the decorative pattern 2 becomes inconspicuous, and the external appearance of the decorative paint deteriorates. can prevent

As described above, according to the first embodiment described above, it is possible to provide a coating technique capable of forming the concave-convex decorative pattern 2 on the object W to be coated.

Further, in the coating method of Embodiment 1, when the droplet diameter of the paint P from the plurality of nozzles 11 and the number of droplets per injection are individually set, in the third step S103, the base coating film 1 It is possible to finely adjust the film thickness of the decorative coating film laminated on the surface 1a of the nozzle 11A for each portion corresponding to each selection nozzle 11A. Thereby, the variation of the kind of decorative pattern 2 can be increased.

Further, in the coating method of Embodiment 1, when the paint P is repeatedly sprayed from the selection nozzle 11A a plurality of times based on the predetermined film thickness of the decorative pattern 2, the paint P is laminated on the surface 1a of the base paint film 1. By increasing the film thickness of the decorative coating film in stages, it becomes possible to easily form the desired concave-convex decorative pattern 2 . In particular, the process of forming the decorative pattern 2 can be simplified by repeatedly spraying the paint P from the same selected nozzle 11A a plurality of times.

Other embodiments related to the first embodiment will be described below with reference to the drawings. In other embodiments, the same reference numerals are given to the same elements as those of the first embodiment, and the description of the same elements will be omitted.

(Embodiment 2)
As shown in FIG. 9, in the second embodiment, instead of the decorative coating process (see FIGS. 2 and 3) of the first embodiment, the process from step S104A to step S107A is performed sequentially. be.

Step S104A is a step that performs the same processing as step S104 of the first embodiment. Step S105A is a step that performs the same processing as step S105 of the first embodiment. Step S106A is a step that performs the same processing as step S106 of the first embodiment. Step S107A is a step for determining whether or not the decorative painting is finished after step S106A. According to this step S107A, if the decorative painting is to be continued ("Yes" in step S107A), the decorative painting process is terminated; otherwise ("No" in step S107A), the process returns to step S106A. .

Others are the same as those of the first embodiment.

According to the second embodiment, the number of processing steps can be reduced compared to the case of the first embodiment, and the processing related to the coating method can be simplified.

In addition, the same effects as those of the first embodiment are obtained.

The present invention is not limited to the exemplary embodiments described above, and various applications and modifications are conceivable without departing from the scope of the present invention. For example, it is also possible to implement the following forms that apply the above-described embodiments.

In the above-described embodiment, the case where the same inkjet head 10 is used in both the first step S101 and the third step S103 was illustrated, but instead of this, different inkjet heads 10 are used in the first step S101 and the third step S103. may be used. Also, the first step S101 may be executed by a coating method other than the inkjet method.

In the above-described embodiment, the case where the decorative coating is applied to the steel plate constituting the body of the automobile as the object W to be coated is exemplified. ) can also be subjected to decorative coating.

1 base coating
1a surface 2 decorative pattern 10 inkjet head 11 nozzle 11A selection nozzle P paint W object to be coated Wa surface S101 1st step (base painting step)
S102 Second step (fixing step)
S103 Third step (decorative coating step)

Claims (5)

a base coating step of forming a base coating film on the surface of the object to be coated;
a fixing step of fixing the base coating film formed in the base coating step to the surface of the object to be coated by drying;
An inkjet head in which a plurality of nozzles are regularly arranged is arranged on the object to be coated, and the paint is ejected only from selected nozzles selected from the plurality of nozzles of the inkjet head and fixed in the fixing step. a decorative coating step of forming an uneven decorative pattern on the surface of the base coating film;
A painting method. 2. The coating according to claim 1, wherein, in the decorating coating step, the spraying process of spraying the coating material from the selected nozzle onto the surface of the base coating film is repeated a plurality of times based on the predetermined film thickness of the decorative pattern. Method. 3. The coating method according to claim 2, wherein in the decorative coating step, the jetting process is repeated a plurality of times using the same selected nozzle. The coating method according to any one of claims 1 to 3, wherein in the base coating step, the base coating film is formed by injecting the coating material from the plurality of nozzles of the inkjet head. 5. The coating method according to any one of claims 1 to 4, wherein at least one of the droplet diameter and the number of droplets per injection of the paint ejected from the plurality of nozzles is individually set.

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