Patent Description:
Painting devices that perform painting using a painting head having multiple nozzles are used in many fields. For example, in automobile manufacturing plants, painting robots are used, which paint the vehicle body of an automobile by moving a painting head installed on a robot arm along the body of the automobile. A painting robot may in some cases perform painting of a vehicle body while switching to coating materials of different colors. When switching the color of the coating material used for painting, cleaning liquid is passed through the coating material supply passage to clean the supply passage, thereby preventing the previously used coating material color from mixing with the color of the coating material to be newly used (see patent document <NUM>).

[Patent document <NUM>] <CIT>. Further documents: <CIT> discloses a liquid ejecting apparatus (a Printer Device). The apparatus has a plurality of nozzles ejecting liquid, a common liquid chamber supplying liquid to the nozzles, a liquid flow path for supplying liquid which is accommodated in a liquid accommodation unit to the common liquid chamber, a liquid flow unit which causes liquid in the liquid flow path to flow; a return flow path which connects the common liquid chamber and the liquid accommodation unit; and valves which close the return flow path. <CIT> discloses an inkjet coating machine. With the device from
<CIT> it is possible to limit the occurrence of settling in the coating components. The machine comprises a robot arm with a chuck on the tip and a nozzle head. The nozzle head unit comprises a nozzle head with a nozzle for discharging a coating material and a head-side circulation route through which the coating material circulates inside the nozzle head. US <NUM>;<NUM>,095B2 discloses a coating device with an application apparatus to discharge a coating agent from a coating agent nozzle. The apparatus is configured to apply an oscillation to the coating agent and/or the coating agent jet such that the coating agent and/or the coating agent jet break up into droplets.

In the painting device described above, the coating material used is a coating material comprising pigment as a main component. Thus, for example, even when painting of an automobile body has been stopped, coating material is circulated to prevent the pigment contained in the coating material from separating or aggregating. For example, the passage through which the coating material is circulated (hereinafter, the coating material circulation passage) comprises many component parts besides the aforementioned painting head, such as a pump for circulating the coating material, etc. The adhesion state of coating material in such a coating material circulation passage differs depending on the component part, and also differs due to concavoconvexities or level differences provided at the connection areas between piping and component parts. Therefore, when cleaning liquid is passed through the coating material circulation passage to clean the coating material circulation passage, the manner in which the coating material adhered to the coating material circulation passage comes off will differ, and in areas where coating material is difficult to wash off with cleaning liquid, residual coating material (more specifically, pigment) will tend to remain.

Furthermore, in the case of a method wherein cleaning liquid is passed through starting from the upstream side of the coating material supply passage or coating material circulation passage to clean the supply passage, the coating material removed by cleaning flows together with the cleaning liquid, so it becomes difficult to obtain a cleaning effect from the cleaning liquid on the downstream side. Thus, there is the problem that, in a method of cleaning by passing cleaning liquid through starting from the upstream side of the supply passage, the cleaning time is prolonged.

The present invention was invented to resolve the problems described above, and has the purpose of providing technology that allows the cleaning time of the coating material circulation passage to be shortened by efficiently obtaining a cleaning effect on the coating material circulation passage in a shorter time.

The painting device of the present invention, intended to solve the problem described above, is a painting device equipped with a painting head having multiple nozzles that discharge coating material, the painting device being characterized in that it comprises a supply passage that supplies the coating material to the painting head, and a return flow passage that returns, to the upstream side of the supply passage, the portion of the coating material supplied to the painting head that was not discharged from the multiple nozzles possessed by the painting head, wherein the supply passage, the painting head and the return flow passage constitute a coating material circulation passage, wherein the coating material circulation passage is divided into multiple segments, each of which contains at least one of the multiple circuit component parts arranged in the coating material circulation passage or the painting head, and wherein the coating material circulation passage allows the multiple segments to be cleaned individually.

The painting device is furthermore characterized in that the multiple segments include a segment in which a first pump that feeds the coating material to the painting head is arranged. The painting device is furthermore characterized in that the multiple segments include a segment in which a filter for removing aggregates contained in the coating material fed from the first pump is arranged.

The painting device is furthermore characterized in that the multiple segments include a segment in which a remover for removing air bubbles contained in the coating material fed from the feed pump is arranged.

The painting device is furthermore characterized in that the multiple segments include a segment in which the painting head is arranged. In this case, the segment in which the painting head is arranged preferably includes a bypass flow passage that causes the coating material supplied to the given segment to flow to the return flow passage without going through the painting head.

The painting device is furthermore characterized in that the multiple segments include a segment in which there is arranged a second pump which draws into the return flow passage, and feeds to the upstream side of the supply passage, the coating material supplied to the painting head that was not discharged from the multiple nozzles possessed by the painting head.

The painting device is furthermore characterized in that cleaning of each segment among said multiple segments is carried out by repeating, one or multiple times, the operation of supplying the cleaning liquid to the segment that is to be cleaned, then supplying the air to that segment, and discharging at least a portion of the supplied cleaning liquid, wherein the supplied quantity of the cleaning liquid and the air in the cleaning operation and the number of repetitions of the cleaning operation differ for each segment among the multiple segments.

According to the invention the coating material circulation passage is divided into the multiple segments by arranging switching valves at multiple locations, wherein the switching valves include a first valve part which is opened when, between two adjacent segments, the coating material is to be passed from the segment located upstream to the segment located downstream in the coating material supply direction; a second valve part which is opened when cleaning liquid or air is to be fed into one of the two adjacent segments; and a third valve part which is opened when the cleaning liquid or the air that has flowed through one of the two adjacent segments is to be discharged to the outside.

The painting device is furthermore characterized in that the painting device is a painting robot which has a robot arm that holds the painting head, and paints an object of painting through actuation of the robot arm and discharge of the coating material from the multiple nozzles possessed by the painting head.

According to the present invention, it is possible to shorten the cleaning time of a coating material circulation passage by more efficiently obtaining a cleaning effect on the coating material circulation passage.

A painting robot <NUM> which implements the present invention will be described below on the basis of the drawings. The painting robot <NUM> of the present embodiment is arranged to the side of a painting line in an automobile manufacturing plant and is used for painting vehicle bodies FR conveyed along the painting line. While a painting robot <NUM> is illustrated below as the painting device of the present invention, the painting device of the present invention can be any painting device having a coating material circulation passage <NUM> as described below and is not limited to the painting robot <NUM>. Furthermore, with regard to the configuration of the painting robot <NUM>, a painting robot is illustrated which is capable of moving a painting head unit <NUM> in three axial directions of X axis, Y axis and Z axis, but the painting robot may also be one which moves the painting head unit <NUM> in one of the X axis, Y axis or Z axis directions, or a painting robot which moves the painting head unit <NUM> in the XY plane, YZ plane or XZ plane.

Although illustration of this will be omitted, the painting robot <NUM> performs painting on a vehicle body FR which is conveyed, for example, from the upstream side of the aforementioned painting line. Here, the painting robot <NUM> may either perform painting on a vehicle body FR that is being conveyed on the painting line, or the painting robot may perform painting on a vehicle body FR that has been conveyed to a predetermined location on the painting line and then stopped. A vehicle body FR which on which painting has been performed by the painting robot <NUM> is conveyed to the downstream side of the painting line.

While the vehicle body FR of an automobile is taken as an example of the object of painting in the following description, the object of painting may also be an automobile part other than a vehicle body (examples include, but are not limited to, doors, hoods, various panels, etc.), or various parts other than automobile parts (for example, airplane or railway exterior parts), and thus is not limited to a vehicle body of an automobile and may be any object that requires painting.

Painting here is performed for the purpose of forming a coating film on the surface of the object of painting to provide protection of that surface and improved appearance. Therefore, painting includes not only the painting of an object of painting using coating material of a specific color or coating material having a specific function, but also the painting of an object of painting using coating materials of multiple colors in sequence. Furthermore, painting includes painting of patterns, illustrations, images, etc..

The painting robot <NUM> is, for example, a multi-jointed robot, but may also be a SCARA robot, so long as it is capable of painting. The painting robot <NUM> shown in <FIG>, as an example, has a base <NUM>, a leg part <NUM>, a rotary drive part <NUM>, a robot arm <NUM> and a painting head unit <NUM>. The base <NUM> is a member which holds the bottom end side of the leg part <NUM> that extends vertically, and which supports the entire painting robot <NUM>. The base <NUM> may for example be fixed to the floor of the painting line or may be movable over the floor of the painting line.

The rotary drive part <NUM> is provided at the upper end of the leg part <NUM>. The rotary drive part <NUM> includes a rotary shaft part <NUM> and a rotary arm <NUM>. The rotary shaft part <NUM> rotates the rotary arm <NUM> through driving with an unillustrated motor, about a center of rotation consisting of, for example, a straight line (in <FIG>, for example, the X axis direction) contained within a plane parallel to the floor. The rotary arm <NUM> rotates the robot arm <NUM>, connected to the rotary arm <NUM>, about a center of rotation consisting of, for example, a straight line (in <FIG>, for example, the Z axis direction) orthogonal to the center of rotation of the rotary shaft part <NUM>.

The robot arm <NUM> includes a first turning arm <NUM> and a second turning arm <NUM>. The first turning arm <NUM> is connected to the rotary arm <NUM> at one end in the direction of extension of the first turning arm <NUM> (in <FIG>, for example, the X axis direction), and turns about a center of turning consisting of a straight line contained in a plane orthogonal to the axial direction of the rotary shaft part <NUM> through driving by an unillustrated motor.

The second turning arm <NUM> is connected to the first turning arm <NUM> at the other end in the direction of extension of the first turning arm <NUM> (in <FIG>, for example, the X axis direction), and turns about a center of turning consisting of a straight line (in <FIG>, for example, the Z axis direction) extending parallel to the direction of the center of rotation of the first turning arm <NUM> on the rotary arm <NUM>.

Furthermore, the second turning arm <NUM> holds a wrist part <NUM> on the other end opposite to the end that is pivotally attached to the first turning arm <NUM>. The wrist part <NUM>, in a state where the painting head unit <NUM> has been held, rotates the held painting head unit <NUM> about a center of rotation consisting of any of the multiple axes which the wrist part itself possesses. Here, the multiple axes are, for example, three axes of different orientation. It should be noted that the number of axes should be two or more.

The painting head unit <NUM> has a painting head <NUM>, circuit component parts including a coating material circulation passage <NUM> and the painting head <NUM>, and as well as a control unit (illustration omitted) which controls the operation of the painting head <NUM> and the coating material circulation passage <NUM>, etc..

<FIG> is a drawing illustrating the schematic configuration of the coating material circulation passage <NUM>. As shown in <FIG>, the coating material circulation passage <NUM> comprises a coating material tank <NUM>, a painting head <NUM>, a supply passage <NUM>, a return flow passage <NUM> and a bypass flow passage <NUM>. The coating material circulation passage <NUM> enables circulation of the coating material stored in the coating material tank <NUM>. For example, when performing painting on a vehicle body FR, in the coating material circulation passage <NUM>, the coating material stored in the coating material tank <NUM> is supplied via the supply passage <NUM> to the painting head <NUM>, and the coating material which was not used up for painting by the painting head <NUM> is returned via the return flow passage <NUM> to the coating material tank <NUM>. Furthermore, when not performing painting on the vehicle body FR, in the coating material circulation passage <NUM>, the coating material stored in the coating material tank <NUM> is made to flow through the supply passage <NUM>, bypass flow passage <NUM> and return flow passage <NUM> in that order and is returned to the coating material tank <NUM>.

In describing the configuration of the coating material circulation passage <NUM> within the supply passage <NUM>, with respect to the supply direction of the coating material, the coating material tank <NUM> side will be referred to as the upstream side and the painting head <NUM> side will be referred to as the downstream side. Furthermore, in describing the configuration of the coating material circulation passage <NUM> within the return flow passage <NUM>, the painting head <NUM> will be referred to as the upstream side and the coating material tank <NUM> side will be referred to as the downstream side.

The coating material tank <NUM> stores coating material to be used during painting of the vehicle body FR using the painting head <NUM>. The coating material tank <NUM> is arranged, for example, outside the painting robot <NUM> (for example, on the floor of the painting room) or on the robot arm <NUM>. It will be noted that coating material is supplied to the coating material tank <NUM> from outside as necessary in the process of performing painting of the vehicle body FR using the painting head <NUM>.

The coating material is for example a water-based coating material or solvent-based coating material using pigment. Therefore, in the present embodiment, the coating material is circulated inside the coating material circulation passage <NUM> to prevent the phenomenon of separation of the pigment contained in the coating material or aggregation of the pigment in the coating material circulation passage <NUM>. Furthermore, by circulating the coating material, the viscosity of the coating material is reduced.

The painting head <NUM> has a nozzle forming surface <NUM> on which multiple nozzles <NUM> are arrayed two-dimensionally, and forms a coating film on the surface of the vehicle body FR by discharging coating material, supplied via the supply passage <NUM>, from each of the multiple nozzles <NUM>. The detailed configuration of the painting head <NUM> will be omitted.

The supply passage <NUM> is a passage which supplies the coating material stored in the coating material tank <NUM> to the painting head <NUM>. The supply passage <NUM> has flow passages 48a, 48b,. , <NUM>, 48i, described later. Furthermore, to the supply passage <NUM>, going from the coating material tank <NUM> toward the painting head <NUM>, there are connected a gear pump <NUM>, a removal filter <NUM> and a deaeration module <NUM>, in the order gear pump <NUM> - removal filter <NUM> - deaeration module <NUM>.

The gear pump <NUM> is arranged, for example, inside the second turning arm <NUM> of the robot arm <NUM>. The gear pump <NUM> draws in coating material stored in the coating material tank <NUM>, the feeds the drawn-in coating material toward the painting head <NUM>. Therefore, the pressure on the upstream side of the gear pump <NUM>, i.e. inside the flow passages 48a, 48b between the coating material tank <NUM> and the gear pump <NUM>, becomes negative, and the coating material stored in the coating material tank <NUM> is drawn into these flow passages 48a, 48b and is then fed from the gear pump <NUM> to the flow passage 48c that is connected to the downstream side of the gear pump <NUM>. Here, the gear pump <NUM> corresponds to the first pump as set forth in the claims.

Within the supply passage <NUM>, a three-way valve <NUM> is connected between the coating material tank <NUM> and the gear pump <NUM>. The three-way valve <NUM> switches between a state in which flow passage 48a is interconnected with flow passage 48b, and a state in which flow passage 48b is interconnected with discharge tank <NUM>. During painting of the vehicle body FR by means of the painting head <NUM>, the three-way valve <NUM> holds the flow passage 48a and the flow passage 48b in an interconnected state, and the coating material stored in the coating material tank <NUM> is made to flow into the supply passage <NUM> by actuating the aforementioned gear pump <NUM>. Furthermore, during cleaning, the three-way valve <NUM> switches from a state in which the flow passage 48a is interconnected with the flow passage 48b to a state in which the flow passage 48b is interconnected with the discharge tank <NUM>, and the cleaning liquid and air flowing through the flow passage 48b in the opposite direction of the coating material supply direction are discharged into the discharge tank <NUM>. Here, the cleaning liquid, when using a coating material that is a mixture of organic solvent and pigment (solvent-based coating material) (in some cases also containing metal granules or metal flakes), is a cleaning liquid having organic solvent as the main ingredient, and in cases of using a coating material using water and pigment (water-based coating material) (in some cases also containing metal granules or metal flakes), the cleaning liquid has water as the main ingredient. Furthermore, the air used for cleaning is compressed air. In the following, the term "air" refers to compressed air.

Within the supply passage <NUM>, a pressure gauge PS is connected to the flow passage 48c that is on the downstream side of the gear pump <NUM>. The pressure gauge PS measures the pressure of coating material fed by the gear pump <NUM>. The gear pump <NUM> is driven and controlled such that the pressure value detected by the pressure gauge PS remains at a constant value.

The supply passage <NUM> connects the switching valve <NUM> to the downstream side end of the flow passage 48c. The switching valve <NUM> has four valve parts 66a, 66b, 66c, 66d, and is able to switch the flow passage of liquid (coating material, cleaning liquid) or gas (air used during cleaning) according to the open/closed state of these valve parts 66a, 66b, 66c, 66d. Here, valves parts 66a, 66b correspond to the first valve part as set forth in the claims. Furthermore, valve part 66c corresponds to the second valve part as set forth in the claims. Moreover, valve part 66d corresponds to the third valve part as set forth in the claims.

For example, valve part 66a is connected to flow passage 48c, and valve part 66b is connected to the flow passage 48d that leads to the removal filter <NUM>. Therefore, for example, during supply of coating material heading from the coating material tank <NUM> to the painting head <NUM>, or during circulation of coating material, these valves 66a and 66b are opened, and the coating material from flow passage 48c flows toward flow passage 48d.

Furthermore, valve part 66c is connected to the cleaning tank <NUM> (more specifically, to an unillustrated flow passage that is connected to the cleaning tank <NUM>). Therefore, for example, during cleaning, if one of the aforementioned valve part 66a or valve part 66b and the valve part 66c are opened, the cleaning liquid supplied from the cleaning tank <NUM> will flow through the opened valve parts into the flow passages connected to the given valve parts.

Furthermore, valve part 66d is connected to the discharge tank <NUM> (more specifically to an unillustrated flow passage that is connected to the discharge tank <NUM>). Therefore, for example, during cleaning, if one of the aforementioned valve part 66a or valve part 66b and the valve part 66d are opened, the cleaning liquid or air that has flowed through the flow passages connected to the opened valve parts will flow through valve part 66d into the discharge tank <NUM>.

In the supply passage <NUM>, on the downstream side of the flow passage 48d connected to the valve part 66b of the switching valve <NUM>, there is connected a removal filter <NUM>. The removal filter <NUM> is installed at a location where operation of the painting robot <NUM> will not affect removal performance of the removal filter <NUM>, such as on the leg part <NUM> of the painting robot <NUM> or the floor of the painting line. The removal filter <NUM> removes coarse foreign matter and foreign matter such as pigment aggregates contained in the coating material that flows through the supply passage <NUM>, and also removes air bubbles contained in the coating material which exceed a predetermined size. The removal filter <NUM> is for example a mesh-like body such as a metal net or resin net, or a porous body, or a metal plate in which fine through-holes have been formed. Examples of a mesh-like body include metal mesh filters, metal fibers, e.g. fine strands of metal known as SUS made into the form of felt, metal sintered filters which have been compressed and sintered, electroformed metal filters, electron beam processed metal filters, laser beam processed metal filters, and the like. Here, the removal filter <NUM> corresponds to the filter as set forth in the claims.

In the supply passage <NUM>, on the downstream side of the flow passage 48e connected to the downstream side of the removal filter <NUM>, there is connected a switching valve <NUM>. The switching valve <NUM>, similarly, to switching valve <NUM>, has four valve parts 67a, 67b, 67c, 67d. Here, valves parts 67a, 67b correspond to the first valve part as set forth in the claims. Furthermore, valve part 67c corresponds to the second valve part as set forth in the claims. Moreover, valve part 67d corresponds to the third valve part as set forth in the claims.

For example, valve part 67a is connected to flow passage 48e, and valve part 67b is connected to the flow passage 48f that leads to the deaeration module <NUM>. Therefore, for example, during supply of coating material heading from the coating material tank <NUM> to the painting head <NUM>, or during circulation of coating material, these valves 67a and 67b are opened, and the coating material from flow passage 48e flows toward flow passage 48f.

Furthermore, valve part 67c is connected to the cleaning tank <NUM> (more specifically, to an unillustrated flow passage that is connected to the cleaning tank <NUM>). Therefore, for example, during cleaning, if one of the aforementioned valve part 67a or valve part 67b and the valve part 67c are opened, the cleaning liquid supplied from the cleaning tank <NUM> will flow through the opened valve parts into the flow passages connected to the given valve parts.

Furthermore, valve part 67d is connected to the discharge tank <NUM> (more specifically to an unillustrated flow passage that is connected to the discharge tank <NUM>). Therefore, for example, during cleaning, if one of the aforementioned valve part 67a or valve part 67b and the valve part 67d are opened, the cleaning liquid or air that has flowed through the flow passages connected to the opened valve parts will flow through valve part 67d into the discharge tank <NUM>.

In the supply passage <NUM>, on the downstream side of the flow passage 48f connected to the valve part 67b of the switching valve <NUM>, there is connected a deaeration module <NUM>. The deaeration module <NUM> is installed at a location where operation of the painting robot <NUM> will not affect the deaeration performance of the deaeration module <NUM>, such as on the leg part <NUM> of the painting robot <NUM> or the floor of the painting line. The deaeration module <NUM> removes (deaerates) dissolved gas and air bubbles present in the coating material. Examples of the deaeration module <NUM> include a hollow fiber membrane bundle made by bundling multiple hollow fiber membranes. Here, the deaeration module <NUM> corresponds to the remover as set forth in the claims.

In the supply passage <NUM>, on the downstream side of the flow passage <NUM> connected to the downstream side of the removal filter <NUM>, there is connected a switching valve <NUM>. The switching valve <NUM>, similarly to switching valve <NUM> and switching valve <NUM>, has four valve parts 68a, 68b, 68c, 68d. Here, valves parts 68a, 68b correspond to the first valve part as set forth in the claims. Furthermore, valve part 68c corresponds to the second valve part as set forth in the claims. Moreover, valve part 68d corresponds to the third valve part as set forth in the claims.

For example, valve part 68a is connected to flow passage <NUM>, and valve part 68b is connected to the flow passage <NUM> that leads to the three-way valve, described later. Therefore, for example, during supply of coating material heading from the coating material tank <NUM> to the painting head <NUM>, or during circulation of coating material, these valves 68a and 68b are opened, and the coating material flowing through flow passage <NUM> flows toward flow passage <NUM>.

Furthermore, valve part 68c is connected to the cleaning tank <NUM> (more specifically, to an unillustrated flow passage that is connected to the cleaning tank <NUM>). Therefore, for example, during cleaning, if one of the aforementioned valve part 68a or valve part 68b and the valve part 68c are opened, the cleaning liquid supplied from the cleaning tank <NUM> will flow through the opened valve parts into the flow passages connected to the given valve parts.

Furthermore, valve part 68d is connected to the discharge tank <NUM> (more specifically to an unillustrated flow passage that is connected to the discharge tank <NUM>). Therefore, for example, during cleaning, if one of the aforementioned valve part 68a or valve part 68b and the valve part 68d are opened, the cleaning liquid or air that has flowed through the flow passages connected to the opened valve parts will flow through valve part 68d into the discharge tank <NUM>.

In the supply passage <NUM>, on the downstream side of the flow passage <NUM> connected to the valve part 68b of the switching valve <NUM>, there is connected a three-way valve <NUM>. During painting of the vehicle body FR by means of the painting head <NUM>, the three-way valve <NUM> maintains the flow passage <NUM> and the flow passage 48i connected to the painting head <NUM> on the downstream side in an interconnected state. Furthermore, when painting of the vehicle body FR by means of the painting head <NUM> is not being performed, the three-way valve <NUM> switches from a state in which flow passage <NUM> and flow passage 48i are interconnected to a state where flow passage <NUM> and bypass flow passage <NUM> are interconnected.

The downstream side of the flow passage 48i and the upstream side of flow passage 49a of the return flow passage <NUM>, described below, are connected to the painting head <NUM>. In the return flow passage <NUM>, a three-way valve <NUM> is connected to the downstream side of flow passage 49a. During painting of the vehicle body FR by means of the painting head <NUM>, the three-way valve <NUM> maintains the flow passage 49a and the flow passage 49b, which is connected to valve part 71a of switching valve <NUM>, described below, on the downstream side, in an interconnected state. Furthermore, when painting of the vehicle body FR by means of the painting head <NUM> is not being performed, the three-way valve <NUM> switches from a state in which flow passage 49a and flow passage 49b are interconnected to a state where bypass flow passage <NUM> and flow passage 49b interconnected.

The return flow passage <NUM> returns coating material that was not used by the painting head <NUM>, or coating material which is circulating through the coating material circulation passage <NUM>, to the upstream side of the supply passage <NUM>, that is, toward the coating material tank <NUM>. The return flow passage <NUM> has flow passages 49a, 49b, 49c, 49d, 49e.

In the return flow passage <NUM>, a switching valve <NUM> is connected to the downstream side of flow passage 49b. The switching valve <NUM>, similarly to switching valve <NUM>, switching valve <NUM> and switching valve <NUM>, has four valve parts 71a, 71b, 71c, 71d. Here, valves parts 71a, 71b correspond to the first valve part as set forth in the claims. Furthermore, valve part 71c corresponds to the second valve part as set forth in the claims. Moreover, valve part 71d corresponds to the third valve part as set forth in the claims.

For example, valve part 71a is connected to flow passage 49b and valve part 71b is connected to flow passage 49c, which connects to gear pump <NUM>, on the downstream side. Therefore, for example, during supply of coating material heading from the coating material tank <NUM> to the painting head <NUM>, or during circulation of coating material, these valves 71a and 71b are opened, and the coating material flowing through flow passage 49b flows toward flow passage 49c.

Furthermore, valve part 71c is connected to the cleaning tank <NUM> (more specifically, to an unillustrated flow passage that is connected to the cleaning tank <NUM>). Therefore, for example, during cleaning, if one of the aforementioned valve part 71a or valve part 71b and the valve part 71c are opened, the cleaning liquid supplied from the cleaning tank <NUM> will flow through the opened valve parts into the flow passages connected to the given valve parts.

Furthermore, valve part 71d is connected to the discharge tank <NUM> (more specifically to an unillustrated flow passage that is connected to the discharge tank <NUM>). Therefore, for example, during cleaning, if one of the aforementioned valve part 71a or valve part 71b and the valve part 71d are opened, the cleaning liquid or air that has flowed through the flow passages connected to the opened valve parts will flow through valve part 71d into the discharge tank <NUM>.

In the return flow passage <NUM>, a gear pump <NUM> is connected to the downstream side of flow passage 49c. The gear pump <NUM> is arranged, for example, inside the second turning arm <NUM> of the robot arm <NUM>. The gear pump <NUM> draws in coating material flowing through the return flow passage <NUM> and feeds it into the flow passage 49d connected on the downstream side of the gear pump <NUM>. Therefore, in the return flow passage <NUM>, flow passage 49c goes to negative pressure, and coating material is drawn into the return flow passage <NUM> and then fed from the gear pump <NUM> into the flow passage 49d connected to the downstream side of the gear pump <NUM>. Here, the gear pump <NUM> corresponds to the second pump as set forth in the claims.

In the return flow passage <NUM>, a three-way valve <NUM> is connected to the downstream side of flow passage 49d. The three-way valve <NUM> switches between a state in which flow passage 49d is interconnected with flow passage 49e, connected to the coating material tank <NUM>, and a state in which flow passage 49d is interconnection with the discharge tank <NUM>. During painting of the vehicle body FR by means of the painting head <NUM> or during circulation of coating material, the three-way valve <NUM> maintains the flow passage 49d and flow passage 49e in an interconnected state. Furthermore, during cleaning, the three-way valve <NUM> switches from a state in which flow passage 49d is interconnected to flow passage 49e to a state in which flow passage 49d is interconnected to the discharge tank <NUM>. As a result, the cleaning liquid and air flowing through flow passage 49e are discharged via the three-way valve <NUM> into the discharge tank <NUM>.

The aforementioned coating material circulation passage <NUM> is divided into multiple segments, and each of the divided segments can be cleaned individually. The multiple segments are, for example, a segment going from the three-way valve <NUM> via gear pump <NUM> to switching valve <NUM>; a segment going from switching valve <NUM> via the removal filter <NUM> to switching valve <NUM>; a segment going from switching valve <NUM> via the deaeration module <NUM> to switching valve <NUM>; a segment going from switching valve <NUM> via the painting head <NUM> to switching valve <NUM>; and a segment going from switching valve <NUM> via gear pump <NUM> to three-way valve <NUM>.

In the following the segment going from the three-way valve <NUM> via gear pump <NUM> to switching valve <NUM> will be referred to as first gear pump section GS1; the segment going from switching valve <NUM> via the removal filter <NUM> to switching valve <NUM> will be referred to as filter section FS; and the segment going from switching valve <NUM> via the deaeration module <NUM> to switching valve <NUM> will be referred to as degassing section DS. Furthermore, the segment going from switching valve <NUM> via painting head <NUM> to switching valve <NUM> will be referred to as head section HS, and the segment going from switching valve <NUM> via gear pump <NUM> to three-way valve <NUM> will be referred to as second gear pump section GS2. The aforementioned head section HS shall be considered to include the bypass flow passage <NUM>.

Among the aforementioned multiple segments, cleaning of the first gear pump section GS1 is performed by opening the valve parts 66a, 66c of switching valve <NUM> and supplying cleaning liquid and air via valve part 66c of switching valve <NUM> to the first gear pump section GS1. At this time, the three-way valve <NUM> may be held in a state in which flow passage 48b is interconnected with the discharge tank <NUM>, or may be switched to a state in which flow passage 48b is interconnected with the discharge tank <NUM> once a predetermined period of time has elapsed after supplying cleaning liquid and air via valve section 66c of switching valve <NUM> to the first gear pump section GS1. As a result, the cleaning liquid and air are supplied though valve part 66c of switching valve <NUM> to the first gear pump section GS1, and are discharged via the three-way valve <NUM> to the discharge tank <NUM> after flowing in a direction opposite to the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. It should be noted that cleaning of the first gear pump section GS1 is carried out by performing the operation of passing through cleaning liquid and air in that order one or multiple times. Here, the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

Cleaning of the filter section FS is carried out by opening valve parts 67a, 67c of switching valve <NUM> and supplying cleaning agent and air via switching valve <NUM> to the filter section FS. At this time, valve parts 66b, 66d of the switching valve <NUM> may be opened simultaneously with valve parts 67a, 67c of switching valve <NUM>, or they may be opened once a predetermined period of time has elapsed after supplying cleaning liquid and air through valve part 67c of switching valve <NUM> to the filter section FS. As a result, the cleaning liquid and air are supplied though valve part 67c of switching valve <NUM> to the filter section FS, and are discharged into the discharge tank <NUM> via the valve part 66d of switching valve <NUM> after flowing in a direction opposite to the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. It should be noted that cleaning of the filter section FS is carried out by performing the operation of, for example, passing through cleaning liquid and air in that order one or multiple times. Here, the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

Furthermore, cleaning of the filter section FS may be carried out by opening valve parts 66b, 66c of switching valve <NUM> and supplying cleaning agent and air via switching valve <NUM> to the filter section FS. In this case, valve parts 67a, 67d of the switching valve <NUM> may be opened simultaneously with valve parts 66b, 66c of switching valve <NUM>, or they may be opened once a predetermined period of time has elapsed after supplying cleaning liquid and air through valve part 66c of switching valve <NUM> to the filter section FS. As a result, the cleaning liquid and air are supplied though valve part 66c of switching valve <NUM> to the filter section FS, and are discharged into the discharge tank <NUM> via the valve part 67d of switching valve <NUM> after flowing in the same direction as the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. In this case, cleaning of the filter section FS is carried out by performing the operation of, for example, passing through cleaning liquid and air in that order one or multiple times. It should be noted that the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

Cleaning of the degassing section DS is carried out by opening valve parts 68a, 68c of switching valve <NUM> and supplying cleaning agent and air via switching valve <NUM> to the degassing section DS. At this time, valve parts 67b, 67d of the switching valve <NUM> may be opened simultaneously with valve parts 68a, 68c of switching valve <NUM>, or they may be opened once a predetermined period of time has elapsed after supplying cleaning liquid and air through valve part 68c of switching valve <NUM> to the degassing section DS. As a result, the cleaning liquid and air are supplied though valve part 68c of switching valve <NUM> to the degassing section DS, and are discharged into the discharge tank <NUM> via the valve part 67d of switching valve <NUM> after flowing in the opposite direction to the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. It should be noted that cleaning of the degassing section DS is carried out by performing the operation of, for example, passing through cleaning liquid and air in that order one or multiple times. Here, the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

Furthermore, cleaning of the degassing section DS may be carried out by opening valve parts 67b, 67c of switching valve <NUM> and supplying cleaning agent and air via switching valve <NUM> to the degassing section DS. In this case as well, valve parts 68a, 68d of the switching valve <NUM> may be opened simultaneously with valve parts 67b, 67c of switching valve <NUM>, or they may be opened once a predetermined period of time has elapsed after supplying cleaning liquid and air through valve part 67c of switching valve <NUM> to the filter section FS. At this time, the cleaning liquid and air are supplied though valve part 67c of switching valve <NUM> to the degassing section DS, and are discharged into the discharge tank <NUM> via the valve part 68d of switching valve <NUM> after flowing in the same direction as the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. In this case as well, cleaning of the degassing section DS is carried out by performing the operation of, for example, passing through cleaning liquid and air in that order one or multiple times. It should be noted that the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

The head section HS, as described above, includes the bypass flow passage <NUM>, and during cleaning of the head section HS, the cleaning is performed in the order bypass flow passage <NUM> - painting head <NUM> - bypass flow passage <NUM>. First, valve parts 71a, 71c of switching valve <NUM> are opened. Furthermore, the three-way valve <NUM> is maintained in a state in which flow passage <NUM> is interconnected with bypass flow passage <NUM>. Furthermore, the three-way valve <NUM> is maintained in a state in which bypass flow passage <NUM> is interconnected with flow passage 49b. As a result, the cleaning liquid and air are supplied though valve part 71c of switching valve <NUM> to the head section HS, and flow through the bypass flow passage <NUM> in the opposite direction to the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. It should be noted that valve parts 68b, 68d of switching valve <NUM> open once a predetermined period of time has elapsed after supplying cleaning liquid and air to the head section HS through valve part 71c of switching valve <NUM>. As a result, the cleaning liquid and air flowing into the bypass flow passage <NUM> of the head section HS are discharged via valve part 68d of switching valve <NUM> into the discharge tank <NUM>. Then, once a predetermined period of time has elapsed after the cleaning liquid and air have been discharged through valve part 68d of switching valve <NUM> into the discharge tank <NUM>, valve parts 68b, 68d of switching valve <NUM> are closed for a time. It should be noted that cleaning of the bypass flow passage <NUM> is carried out by performing the operation of, for example, passing through cleaning liquid and air in that order one or multiple times. Here, the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

Next, three-way valve <NUM> is switched from a state in which the bypass flow passage <NUM> is interconnected with the flow passage <NUM> into a state in which flow passage <NUM> is interconnected with flow passage 48i, and at the same time, three-way valve <NUM> is switched from a state in which the bypass flow passage <NUM> is interconnected with flow passage 49b into a state in which flow passage 49a is interconnected with flow passage 49b. Cleaning liquid and air are supplied through valve parts 71a, 71c of switching valve <NUM> to the head section HS, and flow through flow passage 49a, painting head <NUM> and flow passage 48i in that order. It should be noted that valve parts 68b, 68d of switching valve <NUM> open once a predetermined period of time has elapsed after supplying cleaning liquid and air to the head section HS through valve part 71c of switching valve <NUM>. As a result, discharge into the discharge tank <NUM> takes place via valve part 68d of switching valve <NUM>. Then, once a predetermined period of time has elapsed after the cleaning liquid and air have been discharged through valve part 68d of switching valve <NUM> into the discharge tank <NUM>, valve part 68d of switching valve <NUM> is closed for a time. It should be noted that cleaning of the painting head <NUM> is carried out by performing the operation of, for example, passing through cleaning liquid and air in that order one or multiple times. Here, the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

Finally, three-way valve <NUM> is switched from a state in which flow passage <NUM> is interconnected with flow passage 48i into a state in which the bypass flow passage <NUM> is interconnected with flow passage <NUM>, and at the same time, three-way valve <NUM> is switched from a state in which flow passage 49a is interconnected with flow passage 49b into a state in which the bypass flow passage <NUM> is interconnected with flow passage 49b. The cleaning liquid and air are supplied though valve parts 71a, 71c of switching valve <NUM> to the head section HS, and flow through the bypass flow passage <NUM> in the opposite direction to the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. It should be noted that valve parts 68b, 68d of switching valve <NUM> open once a predetermined period of time has elapsed after supplying cleaning liquid and air to the head section HS through valve part 71c of switching valve <NUM>. As a result, the cleaning liquid and air flowing into the bypass flow passage <NUM> of the head section HS are discharged via valve part 68d of switching valve <NUM> into the discharge tank <NUM>. Then, once a predetermined period of time has elapsed after the cleaning liquid and air have been discharged through valve part 68d of switching valve <NUM> into the discharge tank <NUM>, valve parts 68b, 68d of switching valve <NUM> are closed for a time. It should be noted that cleaning of the bypass flow passage <NUM> is carried out by performing the operation of, for example, passing through cleaning liquid and air in that order one or multiple times. Here, the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

It should be noted that, for cleaning of head section HS described above, rather than opening valve parts 71a, 71c of switching valve <NUM> and valve parts 68b, 68d of switching valve <NUM> and passing cleaning liquid and air through in the opposite direction to the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>, it is also possible to perform cleaning by maintaining valve parts 71a, 71d of switching valve <NUM> and valve parts 68b, 68c of switching valve <NUM> in an open state and passing through cleaning liquid and air in the same direction as the supply direction of coating material.

Cleaning of the second gear pump section GS2 is performed by opening the valve parts 71b, 71c of switching valve <NUM> and supplying cleaning liquid and air via valve part 71c of switching valve <NUM> to the second gear pump section GS2. At this time, the three-way valve <NUM> may be held in a state in which flow passage 49d is interconnected with the discharge tank <NUM>, or may be switched to a state in which flow passage 49d is interconnected with discharge tank <NUM> once a predetermined period of time has elapsed after supplying cleaning liquid and air via valve section 71c of switching valve <NUM> to the second gear pump section GS2. As a result, the cleaning liquid and air are supplied though valve part 71c of switching valve <NUM> to the second gear pump section GS2, and are discharged via the three-way valve <NUM> to the discharge tank <NUM> after flowing in the same direction as the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. It should be noted that cleaning of the second gear pump section GS2 is carried out by performing the operation of passing through cleaning liquid and air in that order one or multiple times. Here, the duration and number of repetitions of passing through cleaning liquid and air may be set at one's discretion.

The cleaning of the head section HS among the multiple segments described above will be explained more concretely below. In the following, the case will be described where the head section HS is cleaned by passing through cleaning liquid and air in the opposite direction to the supply direction of coating material.

As shown in <FIG>, the head section HS is cleaned in multiple steps. The steps for cleaning the head section HS include a first bypass cleaning step, a head cleaning step and a second bypass cleaning step. It should be noted that these steps are carried out, for example, by passing cleaning liquid or air through in the opposite direction to the supply direction of coating material during painting of the vehicle body FR by the painting robot <NUM>. For example, the air pressure value for supplying air to the head section HS is set, as one example, at about <NUM> MPa to <NUM> MPa.

The first bypass cleaning step includes the following first cleaning step through third cleaning step. For the first cleaning step (step S101 in <FIG>), first, cleaning liquid is supplied to flow passage 49b, bypass flow passage <NUM> and flow passage <NUM>, and after these flow passages have been filled with cleaning liquid, air (compressed air) is supplied into the flow passages. Supplying air into these flow passages causes all of the cleaning liquid that had been filled into these flow passages to be discharged. In the first cleaning step, the operation described above is taken to be one turn, and the above-described operation is performed for one or multiple turns. Here, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc..

For the second cleaning step (step S102 in <FIG>), first, a predetermined quantity of cleaning liquid is supplied to flow passage 49b, bypass flow passage <NUM> and flow passage <NUM>, after which air is supplied into these flow passages. Supplying air into the flow passages causes all of the cleaning liquid that had been filled into these flow passages to be discharged. In the second cleaning step, the operation described above is taken to be one turn, and one or multiple such turns are performed. Here, the quantity of cleaning liquid to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc. Furthermore, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc..

Furthermore, in the second cleaning step, when the above-described operation is performed for multiple turns, the quantity of cleaning liquid supplied may be the same for all the turns, or alternatively, an identical quantity of cleaning liquid may be supplied for each turn up to a predetermined number of turns from the start of the second cleaning step, and a different quantity of cleaning liquid may be supplied during subsequent turns. In this case, the second cleaning step may also be treated as multiple different cleaning steps according to the quantity of cleaning liquid supplied.

For the third cleaning step (step S103 in <FIG>), first, cleaning liquid is supplied to flow passage 49b, bypass flow passage <NUM> and flow passage <NUM>, and after these flow passages have been filled with cleaning liquid, air is supplied into the flow passages. Supplying air into these flow passages causes all of the cleaning liquid that had been filled into these flow passages to be discharged. In the third cleaning step, the operation described above is taken to be one turn, and the above-described operation is performed for one or multiple turns. Here, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc..

The bypass flow passage <NUM> is cleaned by performing the first bypass cleaning step including the aforementioned first through third cleaning steps. Then, once the first bypass cleaning step has been completed, the head cleaning step is started. The head cleaning step includes the following fourth cleaning step through sixth cleaning step.

For the fourth cleaning step (step S104 in <FIG>), cleaning liquid is supplied to flow passage 49b, flow passage 49a, the flow passages inside the painting head <NUM>, flow passage 48i and flow passage <NUM>, and after these flow passages have been filled with cleaning liquid, air is supplied into the flow passages. Supplying air into these flow passages causes all of the cleaning liquid that had been filled into these flow passages to be discharged. In the fourth cleaning step, the operation described above is taken to be one turn, and the above-described operation is performed for one or multiple turns. Here, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc..

For the fifth cleaning step (step S105 in <FIG>), after supplying a predetermined quantity of cleaning liquid into flow passage 49b, flow passage 49a, the flow passages inside the painting head <NUM>, flow passage 48i and flow passage <NUM>, air is supplied. Supplying air into these flow passages causes all of the cleaning liquid that had been supplied into these flow passages to be discharged. In the fifth cleaning step, the operation described above is taken to be one turn, and one or multiple such turns are performed. It should be noted that, in the fifth cleaning step, the quantity of cleaning liquid to be supplied may be the same quantity as in the second cleaning step or a different quantity. Furthermore, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc..

Furthermore, in the fifth cleaning step, when the above-described operation is performed for multiple turns, the quantity of cleaning liquid supplied may be the same for all the turns, or alternatively, an identical quantity of cleaning liquid may be supplied for each turn up to a predetermined number of turns from the start of the fifth cleaning step, and a different quantity of cleaning liquid may be supplied during subsequent turns. In this case, the fifth cleaning step may also be treated as multiple different cleaning steps according to the quantity of cleaning liquid supplied.

For the sixth cleaning step (step S106 in <FIG>), cleaning liquid is supplied to flow passage 49b, flow passage 49a, the flow passages inside the painting head <NUM>, flow passage 48i and flow passage <NUM>, and after these flow passages have been filled with cleaning liquid, air is supplied into the flow passages. Supplying air into these flow passages causes all of the cleaning liquid that had been filled into these flow passages to be discharged. In the sixth cleaning step, the operation described above is taken to be one turn, and the above-described operation is performed for one or multiple turns. Here, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc..

The flow passage 49a, the flow passages inside the painting head <NUM>, and flow passage 48i are cleaned by performing the head cleaning step including the fourth through sixth cleaning steps described above. Then, once the head cleaning step has been completed, the second bypass cleaning step is started. The second bypass cleaning step includes the following seventh cleaning step and eighth cleaning step.

For the seventh cleaning step (step S107 in <FIG>), first, a predetermined quantity of cleaning liquid is supplied into flow passage 49b, bypass flow passage <NUM> and flow passage <NUM>, after which air is supplied into these flow passages. Supplying air into these flow passages causes all of the cleaning liquid that had been supplied into these flow passages to be discharged. In the second cleaning step, the operation described above is taken to be one turn, and one or multiple such turns are performed. Here, in the seventh cleaning step, the quantity of cleaning liquid to be supplied may be the same quantity as in the second cleaning step or a different quantity. Furthermore, the time during which cleaning liquid and air are to be supplied may be the same as the time in the second cleaning step or a different time.

Furthermore, in the seventh cleaning step, when the above-described operation is performed for multiple turns, the quantity of cleaning liquid supplied may be the same for all the turns, or alternatively, an identical quantity of cleaning liquid may be supplied for each turn up to a predetermined number of turns from the start of the seventh cleaning step, and a different quantity of cleaning liquid may be supplied during subsequent turns. In this case, the seventh cleaning step may also be treated as multiple different cleaning steps according to the quantity of cleaning liquid supplied.

For the eighth cleaning step (step S108 in <FIG>), first, cleaning liquid is supplied to flow passage 49b, bypass flow passage <NUM> and flow passage <NUM>, and after these flow passages have been filled with cleaning liquid, air is supplied into the aforesaid flow passages. Supplying air into these flow passages causes the cleaning liquid that had been filled into these flow passages to be discharged. In the eighth cleaning step, the operation described above is taken to be one turn, and the above-described operation is performed for one or multiple turns. Here, the time during which cleaning liquid and air are to be supplied may be the same as the time in the third cleaning step or a different time.

The bypass flow passage <NUM> is cleaned again by performing the second bypass cleaning step including the aforementioned seventh and eighth cleaning steps. Cleaning of the head section HS is carried out by performing the first bypass cleaning step, head cleaning step and second bypass cleaning step described above.

It should be noted that while the details regarding the other sections will be omitted, the cleaning is performed in accordance with a cleaning method (cleaning steps) appropriate for the section to be cleaned. Accordingly, cleaning can be performed by a cleaning method appropriate for each section, and as a result, a cleaning effect can be obtained for each section. Furthermore, since cleaning liquid and air are not passed along the coating material circulation passage <NUM> from the upstream side of the coating material circulation passage <NUM>, it becomes possible to shorten the cleaning time required until the flow passages on the downstream side of the coating material circulation passage <NUM> and the component parts possessed by the coating material circulation passage <NUM> have been cleaned.

While it was indicated that the above-described multiple segments can be cleaned independently, it will be noted that the term cleaning independently includes not only cleaning the multiple segments one by one in sequence, but also simultaneously cleaning two adjacent segments from among the multiple segments and simultaneously cleaning every other segment from among the multiple segments.

Therefore, it is also possible to simultaneously clean adjacent segments such as the filter section FS and degassing section DS. For example, in the case of simultaneously cleaning the filter section FS and degassing section DS, for example, valve parts 67a, 67b, 67c of switching valve <NUM> located between the removal filter <NUM> and deaeration module <NUM> are opened, and valve part 66d of switching valve <NUM> and valve part 68d of switching valve <NUM> are also opened. As a result, cleaning liquid or air is supplied via valve part 67c of switching valve <NUM> to the filter section FS and the degassing section DS and is then discharged into the discharge tank <NUM> via valve part 66d of switching valve <NUM> and valve part 68d of switching valve <NUM>.

Furthermore, for example, in the case of simultaneously cleaning the filter section FS and degassing section DS, rather than passing cleaning liquid and air through valve part 67c of switching valve <NUM>, it is also possible to pass cleaning liquid and air through valve part 66c of switching valve <NUM> or valve part 68c of switching valve <NUM>. In this case, the switching valve <NUM> arranged between the removal filter <NUM> and the deaeration module <NUM> is maintained in a state with the valve parts 67a, 67b open, so that cleaning liquid and air flow through the filter section FS and degassing section DS in that order (or the opposite order) and are then discharged into the discharge tank <NUM>.

It should be noted that while the filter section FS and degassing section DS were divided here into multiple segments, it is also possible to treat the filter section FS and degassing section DS as a single segment. In the following, an example of the case where the filter section FS and degassing section DS are cleaned as a single segment will be described.

As shown in <FIG>, the cleaning steps include a degassing section cleaning step and a filter cleaning step. In the case where the filter section FS and degassing section DS are cleaned as a single segment, valve part 67c of switching valve <NUM> is opened and cleaning liquid and air are supplied to each section. Namely, for the degassing section DS, cleaning liquid and air are supplied in the same direction as the supply direction of coating material to perform cleaning, and for the filter section FS, cleaning liquid and air are supplied in the opposite direction to the supply direction of coating material to perform cleaning. It should be noted that, in the case where the filter section FS and degassing section DS are cleaned as a single segment, the switching valves that are opened in order to supply cleaning liquid and air to each section may be changed for each section. It should be noted that, in the description presented below, the pressure of air supplied for cleaning filter section FS and degassing section DS is set, as one example, at about <NUM> MPa to <NUM> MPa. It should be noted that the pressure of the air supplied during cleaning of the other segments besides the head section HS may either be the same pressure or a different pressure from the pressure of the air supplied for cleaning the filter section FS and degassing section DS.

The degassing section cleaning step includes a first cleaning step and a second cleaning step. For the first cleaning step, (step S201 in <FIG>), first, cleaning liquid is supplied into flow passage 48f, the flow passages inside the deaeration module <NUM>, and flow passage <NUM>, and after cleaning liquid has been filled into these flow passages, air (compressed air) is supplied thereto. Supplying air into these flow passages causes all of the cleaning liquid that had been filled into these flow passages to be discharged. In the first cleaning step, the operation described above is taken to be one turn, and the above-described operation is performed for one or multiple turns. Here, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc..

For the second cleaning step, (step S202 in <FIG>), first, a predetermined quantity of cleaning liquid is supplied into flow passage 48f, the flow passages inside the deaeration module <NUM>, and flow passage <NUM>, after which air is supplied thereto. Supplying air into these flow passages causes a portion of the cleaning liquid that had been supplied into these flow passages to be discharged. In the second cleaning step, the operation described above is taken to be one turn, and one or multiple such turns are performed. Here, the quantity of cleaning liquid to be supplied to the aforementioned flow passages is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc. Furthermore, the quantity of cleaning liquid discharged is likewise set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc. Moreover, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc. After the above-described operation has been performed for one or multiple turns, cleaning liquid is supplied into flow passage 48f, the flow passages inside the deaeration module <NUM>, and flow passage <NUM>, filling these flow passages with cleaning liquid. It should be noted that the step of filling with cleaning liquid may also be treated as a different step from the second cleaning step.

Furthermore, in the second cleaning step, when the above-described operation is performed for multiple turns, the quantity of cleaning liquid supplied may be the same for all the turns, or alternatively, an identical quantity of cleaning liquid may be supplied for each turn up to a predetermined number of turns from the start of the second cleaning step, and a different quantity of cleaning liquid may be supplied during subsequent turns. In this case, the second cleaning step may also be defined as multiple different cleaning steps according to the quantity of cleaning liquid supplied.

Taking the above-described first cleaning step and second cleaning step as one turn, the above-described first cleaning step and second cleaning step are performed until a predetermined number of turns is reached (in <FIG>, until the decision in step S203 is Yes). Then, once the predetermined number of turns has been reached (in <FIG>, when the decision in step S203 is Yes), the degassing section cleaning step terminates and the process proceeds to the filter cleaning step. It should be noted that the predetermined number of turns is set at one's discretion according to the structure of the deaeration module <NUM> and the type of coating material used.

The filter cleaning step includes a third cleaning step and a fourth cleaning step. For the third cleaning step (step S204 in <FIG>), first, cleaning liquid is supplied to flow passage 48e, the flow passages inside the removal filter <NUM>, and flow passage 48d, and after these flow passages have been filled with cleaning liquid, air is supplied into the flow passages. Supplying air into these flow passages causes all of the cleaning liquid that had been filled into these flow passages to be discharged. In the third cleaning step, the operation described above is taken to be one turn, and the above-described operation is performed for one or multiple turns. Here, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc..

For the fourth cleaning step, (step S205 in <FIG>), first, a predetermined quantity of cleaning liquid is supplied into flow passage 48e, the flow passages inside the removal filter <NUM>, and flow passage 48d, after which air is supplied thereto. Supplying air into these flow passages causes a portion of the cleaning liquid that had been supplied into these flow passages to be discharged. In the fourth cleaning step, the operation described above is taken to be one turn, and one or multiple such turns are performed. Here, the quantity of cleaning liquid to be supplied to these flow passages is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc. Furthermore, the quantity of cleaning liquid discharged is likewise set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc. Moreover, the time during which cleaning liquid or air is to be supplied is set at one's discretion according to the type of coating material used, the capacity of the flow passages, etc. After the above-described operation has been performed for one or multiple turns, cleaning liquid is supplied into flow passage 48e, the flow passages inside the removal filter <NUM>, and flow passage 48d, filling these flow passages with cleaning liquid. It should be noted that the step of filling with cleaning liquid may also be treated as a different step from the fourth cleaning step.

Furthermore, in the fourth cleaning step, when the above-described operation is performed for multiple turns, the quantity of cleaning liquid supplied may be the same for all the turns, or alternatively, an identical quantity of cleaning liquid may be supplied for each turn up to a predetermined number of turns from the start of the seventh cleaning step, and a different quantity of cleaning liquid may be supplied during subsequent turns. In this case, the fourth cleaning step may also be defined as multiple different cleaning steps according to the quantity of cleaning liquid supplied.

Taking the above-described third cleaning step and fourth cleaning step as one turn, the above-described third cleaning step and fourth cleaning step are performed until a predetermined number of turns is reached (in <FIG>, until the decision in step S206 is Yes). Then, once the predetermined number of turns has been reached (in <FIG>, when the decision in step S206 is Yes), the filter cleaning step terminates. It should be noted that the predetermined number of turns is set at one's discretion according to the structure of the removal filter <NUM> and the type of coating material used.

By performing the degassing section cleaning step and filter section cleaning step in this manner, a segment including the filter section FS and the degassing section DS can be cleaned as a single segment.

The present embodiment is a painting robot <NUM> equipped with a painting head <NUM> having multiple nozzles <NUM> that discharge coating material, characterized in that it comprises a supply passage <NUM> that supplies coating material to the painting head <NUM>, and a return flow passage <NUM> that returns, to the upstream side of the supply passage <NUM>, the portion of the coating material supplied to the painting head <NUM> that was not discharged from the multiple nozzles <NUM> possessed by the painting head <NUM>, wherein the supply passage <NUM>, the painting head <NUM> and the return flow passage <NUM> constitute a coating material circulation passage <NUM>, wherein the coating material circulation passage <NUM> is divided into multiple segments GS1, FS, DS, HS, GS2 each of which includes at least one of the multiple circuit component parts arranged in the coating material circulation passage <NUM> or the painting head <NUM>, wherein the coating material circulation passage <NUM> allows the multiple divided segments GS1, FS, DS, HS, GS2 to be cleaned individually.

For example, if circuit component parts besides the painting head <NUM>, such as pumps <NUM>, <NUM>, deaeration module (remover) <NUM>, removal filter <NUM>, etc. are arranged in the coating material circulation passage <NUM> and coating material is circulated, the state of adhesion of coating material in painting head <NUM> and the aforementioned circuit component parts will differ for each part, and the manner in which the coating material comes off will also differ. Therefore, in the case of a cleaning method wherein cleaning liquid is passed through from the upstream side of the supply passage <NUM> making up the coating material circulation passage <NUM> to clean the coating material circulation passage <NUM>, ingredients (for example, pigment) contained in the coating material will tend to remain in areas where coating material is difficult to wash away with the cleaning liquid, such as at concavoconvexities or level differences due to the structure of the inside of the coating material circulation passage <NUM>. Furthermore, in the case of a method of cleaning the coating material circulation passage <NUM> by rinsing with cleaning liquid from the upstream side of the supply passage <NUM>, ingredients of the coating material removed by cleaning will flow to the downstream portion of the coating material circulation passage <NUM> along with the cleaning liquid, making it more difficult to obtain a cleaning effect from the cleaning liquid on the downstream side of the coating material circulation passage <NUM>. As a result, there is the problem that, in a method of cleaning the coating material circulation passage <NUM> by passing cleaning liquid through starting from the upstream side of the supply passage <NUM>, the cleaning time is prolonged.

In the present invention, the coating material circulation passage <NUM> is divided into multiple segments, each of which contains at least one of multiple circuit component parts or the painting head <NUM>, and individual cleaning of the divided segments is enabled. This makes it possible to perform cleaning in the segment that is to be cleaned using a cleaning method appropriate for the circuit component parts arranged in that segment. Thus, compared to the cleaning method in which the coating material circulation passage <NUM> is cleaned by passing through cleaning liquid starting from the upstream side of the supply passage <NUM>, the cleaning effect of the cleaning liquid (high cleaning performance) can be more readily obtained. Furthermore, compared to a cleaning method in which the entire coating material circulation passage <NUM> is cleaned by passing through cleaning liquid starting from the upstream side of the supply passage <NUM>, the cleaning time can be shortened.

Furthermore, the multiple segments include a first gear pump section GS1 in which a gear pump <NUM> that feeds coating material to the painting head <NUM> is arranged.

This makes it possible to clean the first gear pump section GS1 in which the gear pump <NUM> is arranged by a cleaning method appropriate for the structure of the gear pump <NUM>. Thus, the cleaning performance in respect of the first gear pump section GS1 can be improved.

Furthermore, the multiple segments include a filter section FS in which there is arranged a removal filter <NUM> which removes aggregates contained in the coating material fed by the gear pump <NUM> toward the painting head <NUM>.

This makes it possible to clean the filter section FS in which the removal filter <NUM> is arranged by a cleaning method appropriate to the structure of the removal filter <NUM>. Thus, the cleaning performance in respect of the filter section FS can be improved.

Furthermore, the multiple segments include a degassing section DS in which there is arranged a deaeration module <NUM> which removes air bubbles contained in the coating material fed from the gear pump <NUM>.

This makes it possible to clean the degassing section DS in which the deaeration module <NUM> is arranged by a cleaning method appropriate for the structure of the deaeration module <NUM>. Thus, the cleaning performance in respect of the degassing section DS can be improved.

Furthermore, the multiple segments include a head section HS in which the painting head <NUM> is arranged.

This makes it possible to clean the head section HS in which the painting head <NUM> is arranged by a cleaning method appropriate for the structure of the painting head <NUM>. Thus, the cleaning performance in respect of the head section HS can be improved.

Furthermore, the head section HS in which the painting head <NUM> is arranged includes a bypass flow passage <NUM> which enables flow to the return flow passage <NUM> without going through the painting head <NUM>.

This makes it possible to clean the bypass flow passage <NUM> simultaneously along with cleaning of the painting head <NUM> in the case of a configuration wherein coating material is circulated within the coating material circulation passage <NUM> even when painting is not being performed by the painting head <NUM>.

Furthermore, the multiple segments include a second gear pump section GS2, in which there is arranged a gear pump <NUM> which draws into the return flow passage <NUM>, and feeds to the upstream side of the supply passage <NUM>, the coating material supplied to the painting head <NUM> which was not discharged through the multiple nozzles <NUM> possessed by the painting head <NUM>.

This makes it possible to clean the second gear pump section GS2 in which the gear pump <NUM> is arranged by a cleaning method appropriate for the structure of the gear pump <NUM>. Thus, the cleaning performance in respect of the second gear pump section GS2 can be improved.

Furthermore, the coating material circulation passage <NUM> is divided into the multiple segments GS1, FS, DS, HS, GS2 by arranging switching valves <NUM>, <NUM>, <NUM>, <NUM> at multiple locations, wherein the switching valves <NUM>, <NUM>, <NUM>, <NUM> include a first valve part 66a, 66b, 67a, 67b, 68a, 68b, 71a, 71b which is opened when, between two adjacent segments, the coating material is to be passed from the segment located upstream to the segment located downstream in the coating material supply direction; a second valve part 66c, 67c, 68c, 71c which is opened when cleaning liquid or air is to be fed into one of the two adjacent segments; and a third valve part 66d, 67d, 68d, 71d which is opened when the cleaning liquid or the air that has flowed through one of the two adjacent segments is to be discharged to the outside.

This makes it possible to clear the segment that is to be cleaned simply through switching of the valve parts possessed by the switching valves. Furthermore, not only cleaning liquid but also air can be passed to the segment that is to be cleaned, making it possible to modify the method of cleaning for each segment, for example, by passing cleaning liquid and air in alternation to the segment that is to be cleaned. Thus, the cleaning performance in respect of all the segments and the segment in question is improved.

Furthermore, the cleaning of each segment among the multiple segments GS1, FS, DS, HS, GS2 is carried out by repeating, one or multiple times, the operation of supplying the cleaning liquid to the segment that is to be cleaned, then supplying the air to that segment, and discharging at least a portion of the supplied cleaning liquid, wherein the supplied quantity of the cleaning liquid and the air in the cleaning operation and the number of repetitions of the cleaning operation differ for each segment among the multiple segments GS1, FS, DS, HS, GS2.

This makes it possible to clean the segments using a cleaning method optimal for each of the multiple segments, thus making it easier to obtain a cleaning effect (high cleaning performance) from the cleaning liquid on the coating material circulation passage, and making it possible to shorten the cleaning time for cleaning the entire coating material circulation passage <NUM>.

Furthermore, a painting robot <NUM>, which has a robot arm <NUM> that holds the painting head <NUM> and paints a vehicle body FR by actuating the robot arm <NUM> and discharging coating material from multiple nozzles <NUM> possessed by the painting head <NUM>, is used as a painting device.

Claim 1:
A painting device (<NUM>) equipped with a painting head (<NUM>) having multiple nozzles that discharge a coating material, the painting device (<NUM>) omprises:
a supply passage (<NUM>) that supplies the coating material to the painting head (<NUM>); and
a return flow passage (<NUM>) that returns, to the upstream side of the supply passage (<NUM>), the portion of the coating material supplied to the painting head (<NUM>) that was not discharged from the multiple nozzles (<NUM>) possessed by the painting head (<NUM>), wherein,
the supply passage, the painting head and the return flow passage (<NUM>) constitute a coating material circulation passage (<NUM>);
the coating material circulation passage (<NUM>) is divided into multiple segments, each of which contains at least one of the multiple circuit component parts arranged in the coating material circulation passage or the painting head (<NUM>); characterized in that
the coating material circulation passage is divided into the multiple segments by arranging switching valves (<NUM>, <NUM>, <NUM>, <NUM>) at multiple locations,
wherein the switching valves (<NUM>, <NUM>, <NUM>, <NUM>) include a first valve part (66a, 66b, 67a, 67b, 68a, 68b, 71a, 71b) which is opened when, between two adjacent segments, the coating material is to be passed from the segment located upstream to the segment located downstream in the coating material supply direction; a second valve part (66c, 67c, 68c, 71c) which is opened when cleaning liquid or air is to be fed into one of the two adjacent segments; and a third valve part (66d, 67d, 68d, 71d) which is opened when the cleaning liquid or the air that has flowed through one of the two adjacent segments is to be discharged to the outside, so that the coating material circulation passage allows the multiple segments to be cleaned individually.