JP2014079703A - Electrostatic coating apparatus and grounded state inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve inspection accuracy for grounded state of an object to be coated.SOLUTION: An electrostatic coating apparatus 1 includes: a coating gun 2; a voltage application device 4; a current measuring device 5; and a surface potential measuring device 6. The coating gun 2 to which high voltage has been applied from the voltage application device 4 is positioned apart from the object CD to be coated while the coating is not jetted toward the object CD to be coated, and the current flowing in the coating gun 2 is measured with the current measuring device 5. The coating gun 2 to which high voltage has been applied is positioned apart from the object CD to be coated and an electric charge is charged on the object CD to be coated while the coating is not jetted toward the object CD to be coated, and the coating gun 2 to which high voltage is not applied is positioned apart from the object CD to be coated, and surface potential of the object CD to be coated is measured with the surface potential measuring device 6. The grounded state of the object CD to be coated is inspected based on the current measured with the current measuring device 5 and the surface potential measured with the surface potential measuring device 6.

Description

  The present invention relates to an electrostatic coating apparatus, and more particularly to a technique for inspecting a ground state in an object to be coated.

  When electrostatic coating is performed, it is necessary that at least a portion (painted surface) to which the coating material is applied has conductivity. Therefore, when performing electrostatic coating on highly insulating objects such as resin parts, in general, conductive materials such as carbon black are mixed into the material of the object to be coated, or the surface of the object is electrically conductive. By forming a conductive film (conductive primer), conductivity is imparted to the object to be coated. And in the case of electrostatic coating, a to-be-coated object (application surface) is earth | grounded (grounding).

  By the way, if there is a variation in the conductive performance in each part of the object to be coated (painted surface), there will be a variation in the amount of paint applied, resulting in uneven coating thickness, Color unevenness may occur. In addition, if the ground connection of the object to be coated (painted surface) is uncertain, charges will accumulate on the object to be coated (painted surface) during electrostatic coating, and the object to be coated and the jig placed around this There is a risk that a spark will occur between the device and the like. Therefore, the quality of the ground state of the object to be coated is inspected before electrostatic coating is performed.

  Conventionally, as a technique for inspecting the ground state of an object to be coated, a technique of measuring a resistance value of the object to be coated by bringing a predetermined terminal into contact with the object to be coated (painted surface) is known. However, with this method, there is a risk that wrinkles may adhere to the object to be coated with the contact of the terminals. Therefore, a method for inspecting the ground state of a coating object without contacting the coating object by measuring the surface potential of the coating object after applying an electric charge to the coating object is proposed. (See, for example, Patent Document 1). In addition, by applying a charge to the object to be coated and measuring the surface potential with a coating gun used for electrostatic coating, a dedicated device for inspecting the ground condition is not required, and the production line is shortened. In addition, a technique for reducing the equipment cost has been proposed (see, for example, Patent Document 2).

JP-A-2005-58998 JP 2012-71224 A

  By the way, in the above-mentioned technique, the surface potential cannot be measured accurately due to a failure of a device for measuring the surface potential or a variation in the distance between the device and the object to be coated. There is a risk of being judged.

  This invention is made | formed in view of the said situation, The objective is to provide the electrostatic coating apparatus and earthing | grounding state inspection method which can improve the inspection precision of the earthing state in a to-be-coated article markedly. is there.

  In the following, each means suitable for solving the above-described object will be described in terms of items. In addition, the effect specific to the means to respond | corresponds as needed is added.

Means 1. A paint gun that sprays paint toward the object,
An electrostatic coating apparatus comprising a voltage applying device that applies a high voltage to the coating gun,
A current measuring device for measuring a current flowing through the coating gun;
A surface potential measuring device electrically connected to the coating gun and measuring the surface potential of the object to be coated;
The coating gun to which a high voltage is applied from the voltage application device is disposed at a distance from the coating object in a state where the coating material is not sprayed on the coating object, and the current measuring device To measure the current flowing through the paint gun,
In a state in which paint is not sprayed onto the object to be coated, the paint gun to which a high voltage is applied from the voltage application device is arranged at a distance from the object to be coated to charge the object to be coated. The coating gun to which a high voltage is not applied from the voltage applying device is arranged with a space from the coating object, and the surface potential of the coating object is measured by the surface potential measuring device. And
An electrostatic coating apparatus for inspecting a ground state of the object to be coated based on a current measured by the current measuring apparatus and a surface potential measured by the surface potential measuring apparatus.

  According to the means 1, the ground state of the object to be coated is inspected by the electrostatic coating apparatus having a coating gun without using a dedicated apparatus. Therefore, it is possible to reduce the size and simplification of the manufacturing equipment and reduce the equipment cost.

  Furthermore, according to the above means 1, when a coating gun to which a high voltage is applied is arranged at a distance from the object to be coated, the current flowing through the coating gun is measured, and the charge is charged by the coating gun. The surface potential of the coated object is measured. Then, based on both the measured current and the surface potential, the ground state of the object to be coated is inspected. Therefore, compared with the case where the ground state is inspected based only on the surface potential, the inspection accuracy of the ground state can be significantly improved.

  In order to stably perform electrostatic painting, the current flowing through the painting gun may be measured during painting, but the current flowing through the painting gun during painting varies greatly due to the effects of paint, painting trajectory, etc. . Therefore, if the ground state of the object to be coated is inspected based on the current flowing through the painting gun during painting, the inspection accuracy may be significantly reduced. On the other hand, the current flowing through the coating gun during non-painting does not fluctuate due to the influence of the paint or the paint trajectory. Therefore, as in the above-described means 1, it is possible to realize a good inspection accuracy by inspecting the ground state of the object to be coated based on the current flowing through the coating gun in a state where the paint is not sprayed onto the object to be coated. it can.

  Mean 2. In a state in which paint is not sprayed on the object to be coated, the coating gun to which a high voltage is applied from the voltage application device is arranged at an interval from the object to be coated, and the current measuring device 2. The electrostatic coating apparatus according to claim 1, wherein the current flowing through the coating gun is measured and the object is charged by the coating gun.

  According to the above means 2, in order to measure the current flowing through the coating gun, when the coating gun to which a high voltage is applied is arranged at a distance from the coating object, the charge is applied to the coating object. It is configured to be charged. In other words, the measurement of the current flowing through the coating gun and the charging of the charge on the object to be coated are performed at the same time (that is, in one step). Therefore, it is possible to effectively shorten the inspection time of the ground state in the object to be coated, and to improve the productivity.

Means 3. The paint gun includes a first paint gun and a second paint gun,
The first coating gun to which a high voltage is applied from the voltage application device is arranged at a distance from the object to be charged to charge the object to be charged, and a high voltage is applied from the voltage application device. 3. The means 1 or 2, wherein the second coating gun that is not disposed is arranged at a distance from the object to be coated, and the surface potential of the object to be coated is measured by the surface potential measuring device. Electrostatic coating equipment.

  According to the means 3, it is possible to start measuring the surface potential at a portion of the coating object where the application of the charge is completed while charging the coating object. Therefore, the inspection time for the ground state can be further shortened, and the productivity can be further improved.

  Means 4. The distance between the coating gun and the object to be coated when the current flowing through the coating gun is measured by the current measuring device, and the coating when the surface potential of the object to be coated is measured by the surface potential measuring device Means 1 to 3 characterized in that the distance between the gun and the object to be coated is made smaller than the distance between the painting gun and the object to be coated when the object to be coated is applied by the coating gun. The electrostatic coating apparatus in any one.

  According to the above means 4, the difference between the current flowing through the coating gun when the ground state of the object to be coated is normal and the current flowing through the coating gun when there is an abnormality in the ground state of the object to be coated is ensured. Can be bigger. Moreover, the difference between the surface potential when the ground state of the object to be coated is normal and the surface potential when the ground state of the object to be coated is abnormal can be increased more reliably. Accordingly, normality / abnormality of the ground state in the object to be coated can be more easily discriminated, and the inspection accuracy of the ground state can be further improved.

  Means 5. The means according to any one of means 1 to 4, wherein when the current flowing through the coating gun is measured by the current measuring device, a distance between the coating gun and the object to be coated is 40 mm or more and 100 mm or less. Electrostatic coating equipment.

  According to the means 5, the distance between the coating gun and the object to be coated when measuring the current flowing through the coating gun is set to 40 mm or more. Therefore, when there is a deviation in the position of the object to be coated, the paint gun may come into contact with the object to be coated, or a spark may occur between the paint gun and a jig or the like located around the object to be coated. It can prevent more reliably that it arises. As a result, the ground state can be inspected more accurately.

  Further, according to the above means 5, since the distance between the coating gun and the object to be coated when measuring the current flowing through the coating gun is 100 mm or less, the current flowing through the coating gun when the grounding state is normal And the current flowing through the coating gun when there is an abnormality in the ground state can be further increased. Thereby, the test | inspection precision of a ground state can be improved further.

  Means 6. The means according to any one of means 1 to 5, wherein when the current flowing through the coating gun is measured by the current measuring device, a distance between the coating gun and the object to be coated is 60 mm or more and 80 mm or less. Electrostatic coating equipment.

  According to the above means 6, since the distance between the coating gun and the object to be coated when measuring the current flowing through the coating gun is 60 mm or more, the contact of the coating gun with the object to be coated, the painting gun, the jig, etc. The occurrence of sparks can be prevented very effectively.

  Further, according to the above means 6, since the distance between the coating gun and the object to be coated when measuring the current flowing through the coating gun is 80 mm or less, the current flowing through the coating gun when the grounding state is normal And the current flowing through the coating gun when there is an abnormality in the ground state can be further increased. As a result, the inspection accuracy can be further improved.

Means 7. Ground state inspection method for inspecting the ground state of the object to be coated by an electrostatic coating apparatus comprising a coating gun for spraying a paint toward the object to be coated and a voltage applying device for applying a high voltage to the coating gun Because
In a state where paint is not sprayed on the object to be coated,
Measuring the current flowing through the coating gun when the coating gun to which a high voltage is applied from the voltage application device is disposed at a distance from the object to be coated;
The coating gun, to which a voltage is applied from the voltage application device, is arranged at an interval with respect to the object to be coated to charge the object to be charged, and the surface potential of the object to be coated is measured,
A ground state inspection method comprising: inspecting a ground state of the object to be coated based on a measured current and a surface potential.

  According to the means 7, the same effect as that of the means 1 is achieved.

  Means 8. In a state where paint is not sprayed on the object to be coated, the paint gun to which a high voltage is applied from the voltage application device is arranged with a space from the object to be coated, and flows through the paint gun. The ground state inspection method according to claim 7, wherein the current is measured and the object is charged with the coating gun.

  According to the means 8, the same effect as that of the means 2 is achieved.

  Means 9. 9. The ground state inspection method according to means 7 or 8, wherein in the step of charging the object to be charged, measurement of the surface potential of the object to be coated is started.

  According to the means 9, the same effect as that of the means 3 is achieved.

  Means 10. The distance between the coating gun and the object to be coated when measuring the current flowing through the coating gun, and the distance between the coating gun and the object to be coated when measuring the surface potential of the object to be coated are: The ground state inspection method according to any one of means 7 to 9, wherein a distance between the coating gun and the object to be coated when the object to be coated is applied by the coating gun is made smaller.

  According to the means 10, the same operational effects as the means 4 are achieved.

  Means 11. The ground state inspection method according to any one of means 7 to 10, wherein when the current flowing through the coating gun is measured, a distance between the coating gun and the object to be coated is 40 mm or more and 100 mm or less. .

  According to the means 11, the same effect as that of the means 5 is achieved.

  Means 12. The ground state inspection method according to any one of means 7 to 11, wherein when the current flowing through the coating gun is measured, a distance between the coating gun and the object to be coated is 60 mm or more and 80 mm or less. .

  According to the means 12, the same operational effects as those of the means 6 are achieved.

It is a schematic diagram which shows the structure of an electrostatic coating apparatus. It is a schematic diagram which shows structures, such as a painting gun and a robot arm. It is a schematic diagram which shows the coating gun etc. at the time of measuring the electric current which flows through a coating gun. It is a schematic diagram which shows the coating gun etc. at the time of measuring the surface potential of to-be-coated object. It is a graph which shows the threshold current etc. which are used when determining the electric current measured with the electric current measuring apparatus, and the earth | ground state of to-be-coated material. It is a graph which shows the threshold voltage etc. which are used when determining the surface potential measured by the surface potential measuring device and the ground state of the object to be coated. It is a schematic diagram which shows the distance etc. between a coating gun and the to-be-coated object at the time of coating with respect to the to-be-coated object. It is a schematic diagram which shows the structure of the electrostatic coating apparatus in 2nd Embodiment.

Embodiments will be described below with reference to the drawings.
[First Embodiment]
The electrostatic coating apparatus 1 performs electrostatic coating on an object CD having at least a coated surface having conductivity. As shown in FIG. 1 and FIG. Are provided with a robot arm 3, a voltage applying device 4, a current measuring device 5, and a surface potential measuring device 6. In the present embodiment, a conductive primer having a conductive material is provided on the coated surface of a normal object CD.

  The painting gun 2 is for injecting paint onto the article CD and includes a bell cup 21. Further, the coating gun 2 rotates so that the liquid paint spread on the inner surface of the bell cup 21 can be atomized by centrifugal force by rotating the bell cup 21 by a driving means (for example, an air motor) (not shown). Atomized type.

  The robot arm 3 has an upper and lower arm 31 whose one end is rotatably connected to the base portion 33, and a horizontal arm 32 whose one end is rotatably connected to the other end of the upper and lower arm 31. It has. A coating gun 2 is provided at the other end of the horizontal arm 32. By rotating the upper and lower arms 31 and the horizontal arm 32 at respective rotation fulcrums, the coating gun 2 is applied to the object CD. It can be moved relatively.

  In addition, the horizontal arm 32 includes a first arm part 321, a second arm part 322, and a third arm part 323 connected in series. The first arm portion 321 is provided with two refracting portions 321A and 321B, and the first arm portion 321 can be refracted at the respective refracting portions 321A and 321B. Further, a cylindrical connecting cylinder 324 that connects the first arm part 321 and the coating gun 2 is provided at the other end of the horizontal arm 32, and the connecting cylinder 324 is connected to the first arm part 321. It can be rotated with its own central axis as a rotation axis. By adjusting the refraction angle of the first arm portion 321 and the rotation amount of the connecting cylinder 324, the orientation of the coating gun 2 with respect to the workpiece CD can be adjusted.

  The voltage applying device 4 generates a high voltage to be applied to the coating gun 2 and includes a voltage generating unit 41 and a voltage boosting unit 42.

  The voltage generator 41 generates a voltage that is a source of a high voltage applied to the coating gun 2, and the generated voltage is input to the voltage booster 42. The voltage booster 42 boosts the voltage input from the voltage generator 41 and applies a high voltage to the coating gun 2 via the transmission cable 43. The voltage application device 4 is controlled by a control device 7 having a CPU, a RAM, and the like, and the control device 7 can adjust the application voltage and the voltage application timing to the coating gun 2.

  The current measuring device 5 is provided downstream of the voltage booster 42 and measures the current flowing through the coating gun 2 (in this embodiment, the current flowing through the transmission cable 43). Further, the current measured by the current measuring device 5 is output to the control device 7.

  The surface potential measuring device 6 is provided downstream of the voltage booster 42 and is electrically connected to the coating gun 2. The surface potential measuring device 6 detects a discharge current flowing between the coating gun 2 and the object CD, and measures the surface potential of the object CD based on the detected discharge current. In addition, the surface potential measured by the surface potential measuring device 6 is output to the control device 7.

  The control device 7 determines the applied voltage to the coating gun 2 and the application timing of the voltage, and also based on the current (current value) measured by the current measuring device 5 and the surface potential measured by the surface potential measuring device 6. Then, the ground state of the object CD (in this embodiment, a conductive primer formed on the surface of the object CD) is inspected.

  The method for inspecting the ground state of the article CD will be described in detail. First, after the conductive primer is provided on the article CD, the stage before electrostatic coating is applied to the article CD by the coating gun 2 ( In the state in which the coating material CD is not sprayed), as shown in FIG. 3, the coating gun 2 is arranged at a distance from the coating object CD mounted on a predetermined conveyor CN. At this time, the distance L1 between the coating gun 2 and the object CD is 40 mm or more and 100 mm or less (more preferably, 60 mm or more and 80 mm or less). Normally, the article CD (conductive primer) is electrically connected to the conveyor CN by the earth clip EC, and the article CD (conductive primer) is grounded.

  Next, the application of the negative high voltage (for example, −50 kV, preferably −60 kV or more and −40 kV or less) to the coating gun 2 from the voltage application device 4 and the cancellation of the application are repeated, and a predetermined predetermined value is set. The coating gun 2 is moved relative to the workpiece CD along a locus (in this embodiment, a locus passing over the entire surface of the conductive primer). The current measuring device 5 measures the current flowing through the coating gun 2 when a high voltage is applied to the coating gun 2 and charges the object CD (conductive primer) with the coating gun 2. Let When the paint gun 2 is relatively moved, the distance between the paint gun 2 and the article CD is maintained at the above-described distance L1.

  After a predetermined standby time t1 (for example, 0.2 s) has elapsed after charging the object CD to be charged, a high voltage is applied from the voltage applying device 4 as shown in FIG. A coating gun 2 that is not connected (grounded in this embodiment) is arranged at a distance from the object CD, and has a predetermined trajectory (in this embodiment, on the entire surface of the conductive primer). The trajectory passing through is moved relative to the painting gun 2. Then, the surface potential measuring device 6 detects the discharge current flowing between the coating gun 2 and the object CD by the electric charge charged on the object CD, and the object CD based on the detected discharge current. Measure the surface potential.

  The current (current value) measured by the current measuring device 5 and the surface potential measured by the surface potential measuring device 6 are input to the control device 7, and the control device 7 is based on the input current and surface potential. Then, the ground state of the article CD to be coated is determined.

  More specifically, when the coating object CD (conductive primer) is normally connected to the ground and the conductive primer is normally formed, the charge applied to the coating object CD by the coating gun 2. Flows to the ground side through the conductive primer. Accordingly, the potential difference between the coating gun 2 and the object CD (conductive primer) is relatively large, and the discharge amount from the coating gun 2 is also relatively large. Therefore, as shown in FIG. The maximum measured current (current value) is relatively large. Further, since the charge remaining on the object CD is relatively small, the surface potential measured by the surface potential measuring device 6 is relatively small as shown in FIG. In consideration of this point, the control device 7 has a maximum value of the current (current value) measured by the current measurement device 5 equal to or larger than a predetermined threshold current TI (μA), and the surface potential measurement device. 6 is determined to be normal when the surface potential measured by 6 is equal to or lower than a predetermined threshold voltage TE (kV) set in advance.

  On the other hand, when the ground connection of the object CD (conductive primer) is abnormal (for example, when the earth clip EC is not attached or when the insulating clip adheres to the earth clip EC, etc.) And when the conductive primer is not properly provided (for example, when the conductive primer is not formed), the coating gun 2 applies to the object CD. The applied charge remains on the object CD. Accordingly, the potential difference between the coating gun 2 and the object CD is relatively small, and the discharge amount from the painting gun 2 is also relatively small. Therefore, as shown in FIG. ) Maximum value is relatively small. Further, since the charge remaining on the object CD is relatively large, the surface potential measured by the surface potential measuring device 6 is relatively large as shown in FIG. In consideration of this point, the control device 7 measures the maximum value of the current (current value) measured by the current measuring device 5 or less than the threshold current TI or measured by the surface potential measuring device 6. When the surface potential is larger than the threshold voltage TE, it is determined that the ground state of the article CD is abnormal. In this embodiment, when the control device 7 determines that there is an abnormality in the ground state of the article CD, an operator or the like indicates that there is an abnormality in the ground state by a predetermined notification device (not shown). To be notified.

  In the present embodiment, as described above, the distance L1 between the coating gun 2 and the object CD when measuring the current flowing through the coating gun 2 by the current measuring device 5 is 40 mm or more and 100 mm or less (more preferably The distance L1 is set in this range for the following reason.

  That is, as shown in Table 1, when the applied voltage to the coating gun 2 and the distance L1 between the coating gun 2 and the coating CD are variously changed, the ground state of the coating CD is normal. The difference (current difference) between the current flowing through the coating gun 2 and the current flowing through the coating gun 2 when the ground state of the article CD to be coated is abnormal was determined.

  At this time, by setting the distance L1 to 40 mm or more, it is possible to suppress the current difference from becoming extremely large, so that the occurrence of a spark is sufficiently generated between the coating gun 2 and the jig positioned around the object CD. By making the distance L1 60 mm or more, an excessive increase in the current difference can be more reliably suppressed, and the occurrence of sparks can be more reliably prevented. From this result, in this embodiment, the distance L1 is set to 40 mm or more (more preferably, 60 mm or more). Further, by setting the distance L1 to 100 mm or less, the current difference can be set to 30 μA or more, and it is easy to judge whether the ground state of the article CD is good. By setting the distance L1 to 80 mm or less, the current difference can be reduced. It can be set to 40 μA or more, and it has been found that it is easier to judge whether the ground state is good or bad. Based on this result, in this embodiment, the distance L1 is 100 mm or less (more preferably, 80 mm or less).

  Furthermore, in this embodiment, as shown in FIGS. 3 and 7, the distance L1 is a distance L3 (for example, 150 mm to 200 mm) between the coating gun 2 and the object CD when the electrostatic coating is performed by the coating gun 2. ). Further, a distance L2 (see FIG. 4) between the coating gun 2 and the object CD when the surface potential of the object CD is measured by the surface potential measuring device 6 is set to be smaller than the distance L3. .

  As described above in detail, according to the present embodiment, the ground state of the article CD to be coated is inspected by the electrostatic coating apparatus 1 having the coating gun 2 without using a dedicated apparatus. Therefore, it is possible to reduce the size and simplification of the manufacturing equipment and reduce the equipment cost.

  Further, in the present embodiment, the ground state of the article CD to be coated is inspected based on both the measured current and the surface potential. Therefore, the inspection accuracy of the ground state can be significantly improved.

  Further, in order to measure the current flowing through the coating gun 2, when the coating gun 2 to which a high voltage is applied is arranged at a distance from the coating CD, the charge is charged to the coating CD. It is configured to be. That is, the measurement of the current flowing through the coating gun 2 and the charging of the charge to the article CD are performed at the same time (that is, in one step). Therefore, the inspection time of the ground state in the article CD can be effectively shortened, and the productivity can be improved.

  In addition, in this embodiment, the distance L1 and the distance L2 are smaller than the distance L3. Accordingly, the difference between the current flowing through the coating gun 2 when the ground state of the article CD is normal and the current flowing through the coating gun 2 when the ground state of the article CD is abnormal is more reliably increased. can do. In addition, the difference between the surface potential when the ground state of the object CD is normal and the surface potential when the ground state of the object CD is abnormal can be increased more reliably. Therefore, normality / abnormality of the ground state in the article CD can be more easily determined, and the inspection accuracy of the ground state can be further improved.

  Furthermore, since the distance L1 is 40 mm or more (more preferably, 60 mm or more), the coating gun 2 is in contact with the article CD when the arrangement position of the article CD is shifted. It is possible to more reliably prevent sparks from occurring between the coating gun 2 and the jig or the like positioned around the object CD. As a result, the ground state can be inspected more accurately.

In addition, since the distance L1 is 100 mm or less (more preferably, 80 mm or less), the current flowing through the coating gun 2 when the grounding state is normal and the painting gun 2 when the grounding state is abnormal The difference from the flowing current can be further increased. Thereby, the test | inspection precision of a ground state can be improved further.
[Second Embodiment]
Next, the second embodiment will be described focusing on the differences from the first embodiment. In the first embodiment, only one coating gun 2 is provided. In contrast, in the second embodiment, as shown in FIG. 8, the electrostatic coating apparatus 1 includes a first coating gun 2A and a second coating gun 2B, and has two coating guns. ing. The configuration of both coating guns 2A and 2B is the same as the configuration of the coating gun 2 in the first embodiment. The coating guns 2A and 2B are supported by the robot arm 3 and can be moved relative to the object CD by the operation of the robot arm 3.

  Furthermore, in the second embodiment, the measurement timing of the surface potential by the surface potential measuring device 6 is different from that in the first embodiment. That is, in the first embodiment, the coating gun 2 to which no high voltage is applied is arranged with respect to the coating object CD after a predetermined waiting time t1 has elapsed since the object CD has been charged. The surface potential of the object CD is measured by the surface potential measuring device 6. On the other hand, in the second embodiment, the charge CD is charged by the first coating gun 2A to which a high voltage is applied (that is, all voltage application to the coating CD is performed). The second coating gun 2B to which a high voltage is not applied is arranged on the portion of the article CD to which the charge has been applied, without waiting for completion), and the surface potential measuring device 6 applies the coating. The measurement of the surface potential of the object CD is started.

  As described above, according to the second embodiment, measurement of the surface potential of the object CD can be started while the object CD is being charged. Therefore, the inspection time for the ground state can be further shortened, and the productivity can be further improved.

  In addition, it is not limited to the description content of the said embodiment, For example, you may implement as follows. Of course, other application examples and modification examples not illustrated below are also possible.

  (A) In the above embodiment, the ground state of the article CD is inspected using the maximum value of the current measured by the current measuring device 5 as a determination criterion. However, the maximum value is not necessarily determined as the determination criterion. Therefore, for example, the ground state of the article CD to be coated may be inspected based on the average value of the measured current.

  (B) In the above embodiment, the electrostatic coating apparatus 1 includes one or two coating guns 2, but may include three or more coating guns 2.

  (C) In the above embodiment, the voltage application device 4, the current measurement device 5, and the surface potential measurement device 6 are separately provided. However, these devices may be integrated, and among these devices, These two devices may be integrated. Therefore, for example, the voltage application device 4 may have the function of the current measurement device 5 and the function of the surface potential measurement device 6.

  DESCRIPTION OF SYMBOLS 1 ... Electrostatic coating apparatus, 2 ... Coating gun, 4 ... Voltage application apparatus, 5 ... Current measuring apparatus, 6 ... Surface potential measuring apparatus, CD ... Coated object.

Claims (12)

A paint gun that sprays paint toward the object,
An electrostatic coating apparatus comprising a voltage applying device that applies a high voltage to the coating gun,
A current measuring device for measuring a current flowing through the coating gun;
A surface potential measuring device electrically connected to the coating gun and measuring the surface potential of the object to be coated;
The coating gun to which a high voltage is applied from the voltage application device is disposed at a distance from the coating object in a state where the coating material is not sprayed on the coating object, and the current measuring device To measure the current flowing through the paint gun,
In a state in which paint is not sprayed onto the object to be coated, the paint gun to which a high voltage is applied from the voltage application device is arranged at a distance from the object to be coated to charge the object to be coated. The coating gun to which a high voltage is not applied from the voltage applying device is arranged with a space from the coating object, and the surface potential of the coating object is measured by the surface potential measuring device. And
An electrostatic coating apparatus for inspecting a ground state of the object to be coated based on a current measured by the current measuring apparatus and a surface potential measured by the surface potential measuring apparatus.   In a state in which paint is not sprayed on the object to be coated, the coating gun to which a high voltage is applied from the voltage application device is arranged at an interval from the object to be coated, and the current measuring device 2. The electrostatic coating apparatus according to claim 1, wherein a current flowing through the coating gun is measured, and the object is charged by the coating gun. The paint gun includes a first paint gun and a second paint gun,
The first coating gun to which a high voltage is applied from the voltage application device is arranged at a distance from the object to be charged to charge the object to be charged, and a high voltage is applied from the voltage application device. The second coating gun that is not disposed is arranged at a distance from the object to be coated, and the surface potential of the object to be measured is measured by the surface potential measuring device. The electrostatic coating apparatus described.   The distance between the coating gun and the object to be coated when the current flowing through the coating gun is measured by the current measuring device, and the coating when the surface potential of the object to be coated is measured by the surface potential measuring device 4. The distance between the gun and the object to be coated is made smaller than the distance between the painting gun and the object to be coated when the object to be coated is applied by the coating gun. The electrostatic coating apparatus according to any one of the above.   The distance between the coating gun and the object to be coated is set to 40 mm or more and 100 mm or less when the current flowing through the coating gun is measured by the current measuring device. The electrostatic coating apparatus as described in the item.   The distance between the coating gun and the object to be coated is set to 60 mm or more and 80 mm or less when the current flowing through the coating gun is measured by the current measuring device. The electrostatic coating apparatus as described in the item. Ground state inspection method for inspecting the ground state of the object to be coated by an electrostatic coating apparatus comprising a coating gun for spraying a paint toward the object to be coated and a voltage applying device for applying a high voltage to the coating gun Because
In a state where paint is not sprayed on the object to be coated,
Measuring the current flowing through the coating gun when the coating gun to which a high voltage is applied from the voltage application device is disposed at a distance from the object to be coated;
The coating gun, to which a voltage is applied from the voltage application device, is arranged at an interval with respect to the object to be coated to charge the object to be charged, and the surface potential of the object to be coated is measured,
A ground state inspection method comprising: inspecting a ground state of the object to be coated based on a measured current and a surface potential.   In a state where paint is not sprayed on the object to be coated, the paint gun to which a high voltage is applied from the voltage application device is arranged with a space from the object to be coated, and flows through the paint gun. The ground state inspection method according to claim 7, wherein the current is measured and the object is charged with the coating gun.   The ground state inspection method according to claim 7 or 8, wherein in the step of charging the object to be charged, measurement of a surface potential of the object to be coated is started.   The distance between the coating gun and the object to be coated when measuring the current flowing through the coating gun, and the distance between the coating gun and the object to be coated when measuring the surface potential of the object to be coated are: The ground state inspection according to any one of claims 7 to 9, wherein a distance between the coating gun and the object to be coated when the object to be coated is applied by the coating gun is smaller. Method.   11. The ground according to claim 7, wherein a distance between the coating gun and the object to be coated is 40 mm or more and 100 mm or less when measuring a current flowing through the coating gun. Condition inspection method.   The ground according to any one of claims 7 to 11, wherein when measuring a current flowing through the coating gun, a distance between the coating gun and the object to be coated is 60 mm or more and 80 mm or less. Condition inspection method.

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