Component mounting system and substrate transport control method

Abstract

To provide a technology capable of handling substrates left straddling two adjacent conveyors.SOLUTION: It is determined whether a retraction operation (steps S203 to S206 or step S503) of retracting a board B, which straddles two conveyors (conveyors 21 and 22, conveyors 22 and 23, or conveyors 23 and 24) from the boundary (boundary R1, boundary R2, or boundary R3) is necessary (steps S102, S104, steps S201 to S202, or steps S501 to S502) depending on the length Lb of the board B in the board transport direction X (arrangement direction) and the detection result of the board B by the boundary sensor Sr1, Sr2, or Sr3.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a technique for transporting substrates by a plurality of conveyors arranged in series. [Background technology]

[0002] A component mounting system is known that produces component-mounted boards by using a mounting head to mount components onto boards carried in by multiple conveyors arranged in series. In such component mounting systems, boards may be left on the conveyors before production begins or during interruptions. In such cases, if a board straddles two adjacent conveyors, the following problems may occur.

[0003] In other words, a search for a remaining board can be performed using a sensor that detects the board at the boundary between two adjacent conveyors. In this case, the board is searched for by detecting the board with the sensor while the conveyors are transporting the board in a predetermined direction. However, if a board straddles two conveyors, overdetection may occur, in which after the sensor installed at the boundary between the two conveyors detects the board, a sensor installed downstream in the predetermined direction of the two conveyors also detects the board. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6602584 Summary of the Invention [Problem to be solved by the invention]

[0005] In response to this problem, Patent Document 1 prevents overdetection by selectively operating odd-numbered conveyors among multiple conveyors while checking the results of sensor-based detection of the board, and then selectively operating even-numbered conveyors while checking the results of sensor-based detection of the board. However, operating odd-numbered conveyors before operating even-numbered conveyors results in a long search time for the board. Therefore, there has been a demand for a different technology to deal with boards left straddling two adjacent conveyors.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a technique that can deal with a board that is left straddling two adjacent conveyors. [Means for solving the problem]

[0007] The component mounting system of the present invention comprises N conveyors (N is an integer greater than or equal to 2) arranged in a predetermined arrangement direction and transporting boards in a first direction parallel to the arrangement direction and a second direction opposite to the first direction, a mounting head that mounts components on the boards supported by the conveyors, a boundary sensor that is provided corresponding to the boundary between two adjacent conveyors and detects the boards at the boundary, and a control unit that operates the two conveyors in the first direction to transport the boards in the first direction, and determines whether or not an evacuation operation is required to move the boards straddling the two conveyors away from the boundary, based on the length of the boards in the arrangement direction and the detection result of the boards by the boundary sensor.

[0008] The substrate transport control method of the present invention includes a step of determining whether or not a retraction operation is necessary to retract a substrate from the boundary between two adjacent conveyors in N (N is an integer greater than or equal to 2) conveyors that are arranged in a predetermined arrangement direction and transport substrates in a first direction parallel to the arrangement direction and a second direction opposite to the first direction, and a step of executing the retraction operation when it is determined that the retraction operation is necessary, wherein the necessity of the retraction operation is determined based on the detection result of the substrate by a boundary sensor that is provided corresponding to the boundary between the two adjacent conveyors and detects the substrate at the boundary, and the length of the substrate in the arrangement direction.

[0009] In the present invention (component mounting system and board transport control method) configured in this manner, the necessity of a retraction operation to retract a board straddling two conveyors from the boundary is determined based on the length of the board in the arrangement direction and the detection result of the board by the boundary sensor. Therefore, the retraction operation can be performed based on the determination of necessity, and an operation such as retracting the board from the boundary between the two conveyors can be executed. In this way, it is possible to deal with a board left straddling two adjacent conveyors.

[0010] The component mounting system may also be configured so that the control unit determines that a retraction operation is necessary when the length of the board in the arrangement direction is shorter than the length of the downstream conveyor in the first direction of the two conveyors and the boundary sensor detects the board. This makes it possible to perform an operation such as moving the board left straddling the two conveyors to the downstream conveyor in the first direction of the two conveyors and retracting it from the boundary between the two conveyors. In this way, it is possible to deal with a board left straddling two adjacent conveyors.

[0011] The component mounting system may also be configured such that N is 4 or greater, and the control unit divides the N conveyors into multiple sections, each having a length greater than or equal to 1x and less than 2x the length of the board in the arrangement direction, with two or more conveyors in each section. The control unit determines that a retraction operation to retract the board from a boundary included in a section is unnecessary, while determining whether a retraction operation to retract the board from a section boundary between two adjacent sections is necessary based on the detection result of the board by a boundary sensor disposed corresponding to the section boundary. This configuration is effective when one board is supported per section. In other words, in such a case, even if the board straddles a boundary included in the middle of a section, there is no need to retract the board from the boundary. On the other hand, if the board straddles a section boundary between two adjacent sections, there is a need to retract the board from the section boundary. In contrast, this configuration allows for accurate determination of whether a retraction operation is necessary.

[0012] Furthermore, the component mounting system may be configured so that, when the control unit determines that a retraction operation is necessary, it executes a search operation to search for a conveyor supporting a board from among the N conveyors after the retraction operation, and, when it determines that a retraction operation is unnecessary, it executes the search operation without executing the retraction operation. With such a configuration, the retraction operation is executed depending on whether it is necessary, thereby preventing overdetection of the board during the search operation.

[0013] The component mounting system may also be configured to further include upstream sensors that detect boards at the upstream ends of the N conveyors in the first direction, and the control unit executes a search operation by determining the presence or absence of boards on the N conveyors based on the detection results of the boards by the boundary sensor and the upstream sensor when the N conveyors are operated in the second direction. With this configuration, the boards are detected by the boundary sensor and the upstream sensor, and the search operation can be executed quickly.

[0014] The component mounting system may also be configured so that the control unit executes the search operation by detecting the edge of the board on the downstream side in the second direction with a boundary sensor or an upstream sensor. In this configuration, the edge of the board is detected by the boundary sensor or the upstream sensor, allowing the search operation to be executed quickly.

[0015] The component mounting system may also be configured to further include a positioning sensor that detects the board between both ends of the conveyors in the first direction, and the control unit executes the search operation by determining the presence or absence of the board on the N conveyors based on the detection result of the board by the positioning sensor when the N conveyors are operated in the second direction. With this configuration, the board can be detected by the positioning sensor, and the search operation can be executed quickly.

[0016] The component mounting system may also be configured such that the control unit executes the search operation by detecting the edge of the board downstream in the second direction with a positioning sensor. In this configuration, the positioning sensor detects the edge of the board, allowing the search operation to be executed quickly.

[0017] The component mounting system may also be configured so that the control unit carries in a plurality of boards in order using N conveyors and mounts components on the carried-in boards using the mounting heads, thereby producing a plurality of component-mounted boards, and the control unit performs a search operation before the start of or when the production of the plurality of component-mounted boards is interrupted. With this configuration, it is possible to search for boards left on the conveyors before the start of or when the production of boards is interrupted.

[0018] The component mounting system may also be configured such that, when the length of the board is longer than the length in the arrangement direction of the conveyor that is downstream in the first direction out of the two conveyors, the control unit determines that a retraction operation to retract the board from the boundary is unnecessary. With this configuration, it is possible to accurately determine whether or not a retraction operation is necessary.

[0019] The component mounting system may also be configured so that the length between the two ends of the two conveyors in the arrangement direction is longer than the length of the board, the board on which components are mounted by the mounting head is supported between the two ends of the two conveyors, and the control unit determines whether or not a search operation is required to search for boards left on the N conveyors based on the detection result of the board by the boundary sensor. With this configuration, it is possible to accurately determine whether or not a search operation is required.

[0020] The component mounting system may also be configured to further include an upstream sensor for detecting a board on the upstream side in the first direction for each of the two conveyors, and a downstream sensor for detecting a board on the downstream side in the first direction for each of the two conveyors, and the control unit executes a search operation by determining the presence or absence of a board on the N conveyors based on the detection results of the board by the upstream sensor and the downstream sensor when the N conveyors are operated in the second direction. With this configuration, the upstream sensor and the downstream sensor can detect the board, allowing the search operation to be executed quickly.

[0021] The component mounting system may be configured so that the control unit determines that a search operation is unnecessary when the boundary sensor detects a board, and determines that a search operation is necessary when the boundary sensor does not detect a board. With this configuration, it is possible to accurately determine whether a search operation is necessary.

[0022] The component mounting system may also be configured so that the two conveyors further include a downstream sensor that detects boards downstream in the first direction, the length between both ends of the two conveyors in the arrangement direction is longer than the length of the boards, the boards on which components are mounted by the mounting heads are supported between both ends of the two conveyors, and the control unit determines whether or not a search operation is required to search for boards left on the N conveyors based on the detection result of the boards by the downstream sensor. With this configuration, it is possible to accurately determine whether or not a search operation is required.

[0023] The component mounting system may be configured such that the control unit determines that a search operation is unnecessary when the downstream sensor detects a board, and determines that a search operation is necessary when the downstream sensor does not detect a board. With this configuration, it is possible to accurately determine whether a search operation is necessary.

[0024] The component mounting system may also be configured so that the control unit sequentially carries in a plurality of boards using N conveyors and mounts components on the carried-in boards using the mounting heads, thereby producing a plurality of component-mounted boards, and the control unit determines whether a search operation is necessary before the start of or when the production of the plurality of component-mounted boards is interrupted. With this configuration, it is possible to search for boards left on the conveyors before the start of or when the production of boards is interrupted.

[0025] The component mounting system may also be configured such that the control unit executes the retraction operation by operating the two conveyors in the first direction until the boundary sensor no longer detects the board. This configuration retracts a board left straddling two conveyors from the boundary between the two conveyors. In this way, it is possible to deal with a board left straddling two adjacent conveyors. [Effects of the Invention]

[0026] As described above, according to the present invention, it is possible to deal with a board that is left straddling two adjacent conveyors. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a plan view schematically showing a component mounting machine that is an example of a component mounting system according to the present invention. [Figure 2] FIG. 2 is a block diagram showing an electrical configuration of the component mounter of FIG. 1. [Figure 3] FIG. 4 is a diagram schematically showing a manner in which a substrate is supported by a substrate transport unit. [Figure 4] 10 is a flowchart showing an example of handling remaining substrates. [Figure 5] 5 is a flowchart showing an example of a first preparation executed in response to the remaining substrate in FIG. 4; [Figure 6] FIG. 6 is a diagram schematically showing the operations executed in the first preparation in FIG. 5; [Figure 7] 6 is a flowchart showing an example of a search operation executed in the first preparation of FIG. 5; [Figure 8] FIG. 8 is a diagram illustrating operations performed in the search operation of FIG. 7. [Figure 9] 6 is a flowchart showing an example of a positioning operation executed in the first preparation of FIG. 5; [Figure 10] 10A to 10C are diagrams showing operations performed in the positioning operation of FIG. 9; [Figure 11] 5 is a flowchart showing an example of a second preparation executed in response to the remaining substrate in FIG. 4; [Figure 12] 12 is a diagram schematically showing the operations executed in the second preparation of FIG. 11. FIG. [Figure 13] 13 is a flowchart showing an example of a search operation (section) executed in the second preparation of FIG. 12; [Figure 14] FIG. 14 is a diagram schematically showing the operations executed in the search operation (section) of FIG. 13; [Figure 15]12 is a flowchart showing an example of a positioning operation (section) executed in the second preparation of FIG. 11. [Figure 16] 16 is a diagram showing a schematic diagram of the operation executed in the positioning operation (section) of FIG. 15. [Figure 17] 5 is a flowchart showing an example of a third preparation executed in response to the remaining substrate in FIG. 4. [Figure 18] FIG. 18 is a diagram schematically showing the operations executed in the third preparation of FIG. 17; [Figure 19] 5 is a flowchart showing an example of a fourth preparation executed in response to the remaining substrate in FIG. 4; [Figure 20] FIG. 20 is a diagram schematically showing the operations executed in the fourth preparation of FIG. 19; DETAILED DESCRIPTION OF THE INVENTION

[0028] Fig. 1 is a plan view schematically showing a component mounter that is an example of a component mounting system according to the present invention, and Fig. 2 is a block diagram showing the electrical configuration of the component mounter of Fig. 1. Fig. 1 appropriately shows a horizontal board transport direction X, a width direction Y that is a horizontal direction perpendicular to the board transport direction X, and a vertical direction Z. Furthermore, a forward direction X1 and a reverse direction X2 of the board transport direction X are appropriately shown. Here, the forward direction X1 and the reverse direction X2 are opposite to each other.

[0029] The mounter 1 mounts components E on a board B to produce a component-mounted board, which is a board B on which components E are mounted. As shown in FIG. 2, the mounter 1 includes a control unit 10 that controls each component of the mounter 1. The control unit 10 includes a main control unit 11 that manages the control required for component mounting, and a storage unit 12 that stores programs and data used in component mounting. The main control unit 11 is a processor such as a CPU (Central Processing Unit), and the storage unit 12 is a storage device such as an SSD (Solid State Drive). The storage unit 12 stores a production program 121 that indicates the procedure for mounting components E on the board B, and board-related data 122 that indicates data related to the board B (specifically, the size of the board B, etc.). The control unit 10 also includes a head control unit 13 and a board transport control unit 14.

[0030] 1 includes a board transport unit 2 that transports a board B in a forward direction X1 and a reverse direction X2 of a board transport direction X. This board transport unit 2 has a standby conveyor 21, a mounting conveyor 22, a mounting conveyor 23, and a standby conveyor 24 that are arranged in series in this order in the forward direction X1 of the board transport direction X. In other words, the standby conveyor 21 and the mounting conveyor 22 are adjacent to each other in the board transport direction X with a boundary R1 in between, the mounting conveyor 22 and the mounting conveyor 23 are adjacent to each other with a boundary R2 in between, and the mounting conveyor 23 and the standby conveyor 24 are adjacent to each other with a boundary R3 in between. Each of the conveyors 21, 22, 23, and 24 has two belt conveyors 20 arranged in parallel, and conveys the substrate B in the forward direction X1 by rotating the belt conveyor 20 and moving the upper surface (the surface supporting the substrate B) of the belt conveyor 20 in the forward direction X1, and conveys the substrate B in the reverse direction X2 by moving the upper surface (the surface supporting the substrate B) of the belt conveyor 20 in the reverse direction X2. Note that in this specification, the expression that the conveyor operates in the forward direction X1 (reverse direction X2) will be used appropriately as an expression indicating that the upper surface of the belt conveyor 20 of the conveyor moves in the forward direction X1 (reverse direction X2).

[0031] The standby conveyor 21 supports the board B carried in from the upstream side in the forward direction X1, and keeps the board B on standby. The standby conveyor 21 also transports the board B in the forward direction X1, thereby transferring the board B to the mounting conveyor 22. The mounting conveyor 22 supports the board B received from the standby conveyor 21. In this way, components E are mounted on the board B supported by the mounting conveyor 22. The mounting conveyor 22 also transports the board B in the forward direction X1, thereby transferring the board B to the mounting conveyor 23. The mounting conveyor 23 supports the board B received from the mounting conveyor 22. In this way, components E are mounted on the board B supported by the mounting conveyor 23. The mounting conveyor 23 also transports the board B in the forward direction X1, thereby transferring the board B to the standby conveyor 24. The standby conveyor 24 supports the board B received from the mounting conveyor 23, and keeps the board B on standby. Furthermore, the standby conveyor 24 conveys the board B in the forward direction X1, thereby carrying out the board B downstream in the forward direction X1. These conveyors 21, 22, 23 and 24 operate under the control of the board transport control unit 14.

[0032] The mounter 1 also includes a board detection unit Ud that uses board sensors to detect the position of the board B supported by the board transport unit 2. The board detection unit Ud includes a trailing edge sensor Su, a boundary sensor Sr1, a boundary sensor Sr2, a boundary sensor Sr3, and a leading edge sensor Sd, arranged in this order in the forward direction X1 of the board transport direction X. These sensors Su, Sr1, Sr2, Sr3, and Sd are, for example, optical sensors that output an ON signal to the board transport control unit 14 while detecting the board B and output an OFF signal to the board transport control unit 14 while not detecting the board B. The trailing edge sensor Su is located at the upstream end of the standby conveyor 21 in the forward direction X1 and detects the presence or absence of the board B at this upstream end. The boundary sensor Sr1 is located at the boundary R1 between the standby conveyor 21 and the mounting conveyor 22 in the forward direction X1 and detects the presence or absence of the board B at this boundary R1. The boundary sensor Sr2 is disposed corresponding to the boundary R2 between the mounting conveyor 22 and the mounting conveyor 23 in the forward direction X1, and detects the presence or absence of a board B at the boundary R2. The boundary sensor Sr3 is disposed corresponding to the boundary R3 between the mounting conveyor 23 and the standby conveyor 24 in the forward direction X1, and detects the presence or absence of a board B at the boundary R3. The front end sensor Sd is disposed corresponding to the downstream end of the standby conveyor 24 in the forward direction X1, and detects the presence or absence of a board B at the downstream end.

[0033] The substrate transport control unit 14 then positions the substrate B in the substrate transport direction X by controlling the substrate transport unit 2 based on the position of the substrate B detected by the substrate detection unit Ud. In other words, the substrate transport unit 2 does not have a stopper that abuts against the substrate B to position the substrate B (stopperless). Therefore, the substrate transport control unit 14 positions the substrate B by moving the upper surface of the belt conveyor 20 of the conveyor 21, 22, 23, or 24 by a predetermined amount from the timing when the substrate detection unit Ud detects the substrate using the substrate sensor. The amount of movement of the belt conveyor 20 is obtained by the substrate transport control unit 14 from the encoder output of the motor that drives the belt conveyor 20 of the conveyor 21, 22, 23, or 24.

[0034] The mounter 1 also includes two head units 3, each of which mounts a component E on a board B, and a head drive unit 4 that independently drives the two head units 3 in the board transport direction X and width direction Y. The head drive unit 4 can be configured by applying a known XY drive mechanism. The drive of each head unit 3 by the head drive unit 4 is controlled by the head control unit 13 based on the production program 121.

[0035] Furthermore, the component mounter 1 is equipped with two component supply units 5. The two component supply units 5 are arranged on either side of the board transport unit 2 in the width direction Y, sandwiching the board transport unit 2 therebetween. In each component supply unit 5, a plurality of tape feeders 51 are arranged in the board transport direction X, and each tape feeder 51 feeds out a carrier tape that stores components E in the width direction Y, thereby supplying components E to a component supply position provided at the tip on the board transport unit 2 side in the width direction Y. Note that the feeder used by the component supply unit 5 to supply components E is not limited to the tape feeder 51, and may be, for example, a tray feeder that supplies components E placed on a tray.

[0036] The head unit 3 has a plurality of mounting heads 31 (six in the example of FIG. 1) arranged in the substrate transport direction X. The mounting heads 31 have an elongated shape extending in the Z direction, and can suck and hold components E using nozzles detachably attached to the lower ends of the mounting heads 31. The mounting heads 31 then mount the components E on the substrate B by transferring the components E picked up from the tape feeders 51 using these nozzles.

[0037] As shown in FIG. 1, each of the standby conveyors 21 and 24 has a length Lcw in the board transport direction X, and each of the mounting conveyors 22 and 23 has a length Lcm in the board transport direction X. Here, the length Lcm of each of the mounting conveyors 22 and 23 is longer than the length Lcw of each of the standby conveyors 21 and 24. Furthermore, in the board transport direction X, the length between the ends of the mounting conveyor 22 and the mounting conveyor 23 is length Lcmm, and the length between the ends of the mounting conveyor 23 and the standby conveyor 24 (the length between the ends of the standby conveyor 21 and the mounting conveyor 22) is length Lcmw. Here, the length between the ends of the multiple conveyors in the board transport direction X refers to the length between the most upstream end of the most upstream conveyor and the most downstream end of the most downstream conveyor among the multiple conveyors in the board transport direction X (in other words, the forward direction X1). The board transport unit 2 can support the board B in each of the modes shown in FIG. 3 according to the length Lb of the board B in the board transport direction X.

[0038] 3 is a diagram schematically showing how a board is supported by the board transport unit. When the length Lb of board B is length Lb1, which is less than or equal to length Lcw, board B can be supported by each of standby conveyor 21, mounting conveyor 22, mounting conveyor 23, and standby conveyor 24. Therefore, two boards B on which components E are mounted by mounting head 3 are supported by mounting conveyor 22 and mounting conveyor 23, respectively. Furthermore, boards B waiting for mounting of components E by mounting head 3 are supported by standby conveyor 21, and boards B on which mounting of components E by mounting head 3 has been completed are supported by standby conveyor 24. Therefore, the maximum number of boards B that can be supported by board transport unit 2 is four.

[0039] When the length Lb of the board B is length Lb2, which is longer than length Lcw but less than length Lcm, the board B can fit on both the mounting conveyor 22 and the mounting conveyor 23, but cannot fit on either the standby conveyor 21 or the standby conveyor 24. Therefore, as shown in the "Mounting" column, the two boards B on which components E are mounted by the mounting head 3 are supported by the mounting conveyor 22 and the mounting conveyor 23, respectively, but the boards B are not supported by either the standby conveyor 21 or the standby conveyor 24. Also, as shown in the "Standby" column, the board B after mounting components E by the mounting head 3 is supported by both the mounting conveyor 23 and the standby conveyor 24, straddling them. Similarly, the board B before mounting components E by the mounting head 3 is supported by both the standby conveyor 21 and the mounting conveyor 22, straddling them. Therefore, the maximum number of boards B that can be supported by the board transport unit 2 is two.

[0040] When the length Lb of the board B is length Lb3, which is longer than length Lcm but less than length Lcmw, the board B cannot fit on any of the standby conveyor 21, mounting conveyor 22, mounting conveyor 23, and standby conveyor 24. Therefore, as shown in the "Mounting" column, the two boards B on which components E are mounted by the mounting head 3 are supported by straddling both the mounting conveyor 22 and the mounting conveyor 23. Also, as shown in the "Standby" column, the board B before the mounting of components E by the mounting head 3 is supported by straddling both the standby conveyor 21 and the mounting conveyor 22, and the board B after the mounting of components E by the mounting head 3 is supported by straddling both the mounting conveyor 23 and the standby conveyor 24. Therefore, the maximum number of boards B that can be supported by the board transport unit 2 is two.

[0041] When the length Lb of the board B is length Lb4, which is longer than length Lcmw but shorter than length Lcmm, the board B cannot fit on any of the standby conveyor 21, the mounting conveyor 22, the mounting conveyor 23, and the standby conveyor 24. Therefore, as shown in the "Mounting" column, the two boards B on which components E are mounted by the mounting head 3 are supported by straddling both the mounting conveyor 22 and the mounting conveyor 23. Also, as shown in the "Standby" column, the board B after mounting components E by the mounting head 3 is supported by straddling the mounting conveyor 22, the mounting conveyor 23, and the standby conveyor 24. Similarly, the board B before mounting components E by the mounting head 3 is supported by straddling the standby conveyor 21, the mounting conveyor 22, and the mounting conveyor 23. Therefore, the board transport unit 2 can support a maximum of one board B.

[0042] In the component mounter 1 described above, the control unit 10 controls the storage unit 12 and the board transport control unit 14 based on the production program 121, thereby carrying out board production in which a plurality of component-mounted boards are produced by sequentially carrying in a plurality of boards B using the board transport unit 2 and mounting components E on the plurality of carried-in boards B using the mounting head 3. At this time, before the start or interruption of board production, there may be a board B left behind on the board transport unit 2. In order to deal with such a left-behind board B, the main control unit 11 executes the remaining board handling process shown in FIG. 4.

[0043] Fig. 4 is a flowchart showing an example of how to deal with remaining boards. In step S101 of Fig. 4, the main control unit 11 determines whether the conditions for executing each operation to deal with the remaining board B have been met. For example, the execution conditions may be set to occur before board production starts or when board production is interrupted (i.e., before restarting after interruption). Specific examples of the execution conditions are not limited to these, and may also be set to occur immediately after powering on the mounter 1, when an error occurs in the transport of board B by the board transport unit 2, when the cover of the mounter 1 is opened or closed, or when an operator manually operates the conveyors 21, 22, 23, or 24.

[0044] When the main control unit 11 determines that the execution conditions are met ("YES" in step S101), it issues a command to the substrate transport control unit 14 to execute steps S102 to S108, and the substrate transport control unit 14 executes steps S102 to S108 in accordance with the command received from the main control unit 11. In particular, the substrate transport control unit 14 selects and executes the operation to be executed from among first preparation (step S103), second preparation (step S105), third preparation (step S107), and fourth preparation (step S108) according to the length Lb of the substrate B. These preparations are to be executed before the substrate transport unit 2 starts transporting the substrate B for substrate production.

[0045] That is, in step S102, it is determined whether the length Lb of the substrate B is equal to or less than the length Lcw of the standby conveyors 21, 24, in other words, whether it corresponds to the length Lb1 shown in Fig. 3. If the length Lb of the substrate B is equal to or less than the length Lcw of the standby conveyors 21, 24 (if "YES" in step S102), the first preparation in step S103 is executed.

[0046] Figure 5 is a flowchart showing an example of the first preparation performed in response to the remaining substrate in Figure 4, Figure 6 is a diagram showing schematically the operations performed in the first preparation in Figure 5, Figure 7 is a flowchart showing an example of the search operation performed in the first preparation in Figure 5, Figure 8 is a diagram showing schematically the operations performed in the search operation in Figure 7, Figure 9 is a flowchart showing an example of the positioning operation performed in the first preparation in Figure 5, and Figure 10 is a diagram showing schematically the operations performed in the positioning operation in Figure 9.

[0047] In the first preparation of Fig. 5, the board transport control unit 14 checks the output of each of the boundary sensors Sr1, Sr2, and Sr3 (step S201) and determines whether the outputs of all of the boundary sensors Sr1, Sr2, and Sr3 are off (step S202). If the output of at least one of the boundary sensors Sr1, Sr2, and Sr3 is on ("NO" in step S202), steps S203 to S206 are executed. In the example shown in the "S201" column of Fig. 6, board B is left straddling the mounting conveyor 22 and the mounting conveyor 23, and board B is left straddling the mounting conveyor 23 and the standby conveyor 24. Therefore, the boundary sensors Sr2 and Sr3 output on, and the determination in step S202 is "NO."

[0048] In step S203, it is determined whether the conveyors upstream and downstream of the sensor that is confirmed to output an OFF signal among the boundary sensors Sr1, Sr2, and Sr3 (i.e., two conveyors adjacent to each other across the boundary corresponding to that sensor) are operating. In the example shown in the "S201" column of FIG. 6, the boundary sensor Sr1 outputs an OFF signal, so it is determined whether the standby conveyor 21 and the mounting conveyor 22 upstream and downstream of that boundary sensor Sr1 are operating (step S203). If both the upstream and downstream conveyors (the standby conveyor 21 and the mounting conveyor 22) are stopped ("NO" in step S204), the process proceeds to step S206. On the other hand, if at least one of the upstream and downstream conveyors (the standby conveyor 21 and the mounting conveyor 22) is operating ("YES" in step S204), the process stops that at least one conveyor (step S205) and then proceeds to step S206.

[0049] In step S206, the board transport control unit 14 operates the conveyors upstream and downstream of the boundary sensor Sr1, Sr2, or Sr3 that is confirmed to output an ON signal in the forward direction X1. In the example shown in the "S201" column of FIG. 6, the boundary sensor Sr2 outputs an ON signal, so the mounting conveyor 22 and the mounting conveyor 23 upstream and downstream of the boundary sensor Sr2 operate in the forward direction X1 (step S206). In addition, the boundary sensor Sr3 outputs an ON signal, so the mounting conveyor 23 and the standby conveyor 24 upstream and downstream of the boundary sensor Sr3 operate in the forward direction X1 (step S206). As a result, as shown by the arrows in the "S206" column of FIG. 6, the board B that overlaps the boundary R2 moves in the forward direction X1, and the board B that overlaps the boundary R3 moves in the forward direction X1.

[0050] Following step S206, the process returns to step S201. That is, the output of each of the boundary sensors Sr1, Sr2, and Sr3 is confirmed (step S201), and it is determined whether the outputs of all of the boundary sensors Sr1, Sr2, and Sr3 are OFF (step S202). In the example shown in the "S201_2" column in FIG. 6, the board B straddles the mounting conveyors 22 and 23, and the boundary sensor Sr2 outputs ON, so the determination in step S202 is "NO." Note that, as the mounting conveyor 23 and the standby conveyor 24 move in the forward direction X1 starting in step S206, the board B retreats from the boundary R3 to the forward direction X1, and therefore the output of the boundary sensor Sr3 changes from ON to OFF.

[0051] In step S203, it is determined whether the conveyors upstream and downstream of the sensor that is confirmed to output an OFF signal among the boundary sensors Sr1, Sr2, and Sr3 (i.e., two conveyors adjacent to each other across the boundary corresponding to that sensor) are operating. In the example shown in the "S201_2" column in FIG. 6, the boundary sensors Sr1 and Sr3 output OFF signals, so it is determined whether the standby conveyor 21 and the mounting conveyor 22 upstream and downstream of the boundary sensor Sr1 are operating, and it is also determined whether the mounting conveyor 23 and the standby conveyor 24 upstream and downstream of the boundary sensor Sr3 are operating (step S203). In this example, the mounting conveyor 23 and the standby conveyor 24 are operating ("YES" in step S204), so the mounting conveyor 23 and the standby conveyor 24 are stopped (step S205), and then the process proceeds to step S206.

[0052] In step S206, the board transport control unit 14 operates the conveyors upstream and downstream of the sensor that is confirmed to output ON among the boundary sensors Sr1, Sr2, and Sr3 in the forward direction X1. In the example shown in the "S201_2" column in Fig. 6, the boundary sensor Sr2 outputs ON, so the mounting conveyors 22 and 23 upstream and downstream of the boundary sensor Sr2 operate in the forward direction X1 (step S206).

[0053] Following step S206, the process returns to step S201. That is, the output of each of the boundary sensors Sr1, Sr2, and Sr3 is checked (step S201), and it is determined whether the outputs of all of the boundary sensors Sr1, Sr2, and Sr3 are OFF (step S202). In the example shown in the "S201_3" column in FIG. 6, the substrate B has retreated in the forward direction X1 from all of the boundaries R1, R2, and R3, and all of the boundary sensors Sr1, Sr2, and Sr3 output OFF ("YES" in step S202). Therefore, the substrate transport control unit 14 stops all of the conveyors 21, 22, 23, and 24 (step S207).

[0054] By executing steps S203 to S206 (evacuation operation) in this manner, the board B that straddled the mounting conveyor 22 and the mounting conveyor 23 before the start of the first preparation is evacuated in the forward direction X1 from the boundary R2 between the mounting conveyor 22 and the mounting conveyor 23, and the board B that straddled the mounting conveyor 23 and the standby conveyor 24 is evacuated in the forward direction X1 from the boundary R3 between the mounting conveyor 23 and the standby conveyor 24 ("S201_3" in Figure 6 or the "Before search operation starts" column in Figure 8).

[0055] When steps S201 to S207, including the retraction operation (steps S203 to S206), are completed, a search operation is executed (step S208). In the search operation shown in FIG. 7, the board transport control unit 14 operates all of the conveyors 21, 22, 23, and 24 in the reverse direction X2 (step S301). As a result, the boards B supported by the board transport unit 2 (specifically, the three boards B supported by the standby conveyor 21, the mounting conveyor 23, and the standby conveyor 24) move in the reverse direction X2 (arrows in the "S301" column in FIG. 8). In step S302, the board transport control unit 14 determines whether each of the conveyors 21, 22, 23, and 24 has moved a predetermined distance. This predetermined distance is set according to the length of each of the conveyors 21, 22, 23, and 24. For example, the predetermined distance set for the standby conveyors 21 and 24 can be length Lcw, and the predetermined distance set for the mounting conveyors 22 and 23 can be length Lcm.

[0056] If each of the conveyors 21, 22, 23, and 24 has not moved the predetermined distance ("NO" in step S302), the board transport control unit 14 determines whether or not the board B has been detected for all of the conveyors 21, 22, 23, and 24 (step S303). Here, detecting the board B for the standby conveyor 21 means that the rear end sensor Su provided at the downstream end of the standby conveyor 21 in the reverse direction X2 detects the board B, detecting the board B for the mounting conveyor 22 means that the boundary sensor Sr1 corresponding to the boundary R1 on the downstream side of the mounting conveyor 22 in the reverse direction X2 detects the board B, detecting the board B for the mounting conveyor 23 means that the boundary sensor Sr2 corresponding to the boundary R2 on the downstream side of the mounting conveyor 23 in the reverse direction X2 detects the board B, and detecting the board B for the standby conveyor 24 means that the boundary sensor Sr3 corresponding to the boundary R3 on the downstream side of the standby conveyor 24 in the reverse direction X2 detects the board B.

[0057] In the example shown in the "S301" column of Figure 8, since board B has not been detected on any of conveyors 21, 22, 23, and 24 ("NO" in step S303), the process proceeds to step S304. In step S304, board transport control unit 14 determines whether any of sensors Su, Sr1, Sr2, and Sr3 outputs an ON signal (ON output sensor). If no ON output sensor exists ("NO" in step S304), the process returns to step S302.

[0058] On the other hand, if there is an ON output sensor ("YES" in step S304), the board transport control unit 14 stops the conveyor corresponding to the ON output sensor (step S305). Here, the conveyor corresponding to the trailing end sensor Su is the standby conveyor 21, the conveyor corresponding to the boundary sensor Sr1 is the mounting conveyor 22, the conveyor corresponding to the boundary sensor Sr2 is the mounting conveyor 23, and the conveyor corresponding to the boundary sensor Sr3 is the standby conveyor 24. That is, in step S305, the board B detected by the ON output sensor is stopped. Following step S305, the process returns to step S302.

[0059] 8, the boundary sensors Sr2 and Sr3 each output ON, so the mounting conveyor 23 and the standby conveyor 24 are stopped. On the other hand, the trailing edge sensor Su and the boundary sensor Sr1 output OFF, so the standby conveyor 21 and the mounting conveyor 22 continue to operate in the reverse direction X2.

[0060] Steps S303 to S305 are Each of the conveyors 21, 22, 23, and 24 operates a predetermined distance ("YES" in step S302, Board B is detected on all of conveyors 21, 22, 23, and 24 (YES in step S303). On the other hand, if any of these conditions is met, then in step S306, all of the conveyors 21, 22, 23 and 24 are stopped, and the search operation in FIG. 7 is completed.

[0061] In the example shown in the "S304" column of FIG. 8, each of the conveyors 21, 22, 23, and 24 has not moved a predetermined distance ("NO" in step S302). Also, board B has not been detected on the standby conveyor 21 ("NO" in step S303). Therefore, steps S304 to S305 are executed in the same manner as described above. As in the example shown in the "S304_2" column of FIG. 8, when the trailing end sensor Su outputs ON ("YES" in step S304), the board transport control unit 14 stops the standby conveyor 21 corresponding to the trailing end sensor Su, and stops the board B detected by the trailing end sensor Su (step S305).

[0062] 8, the condition of step S303 is not satisfied because there is no board B corresponding to mounting conveyor 22. Therefore, when mounting conveyor 22 moves a predetermined distance ("YES" in step S302), all of conveyors 21, 22, 23, and 24 are stopped (step S306), and the search operation in FIG. 7 ends.

[0063] By executing steps S208, S301 to S306 (search operation) in this manner, the upstream end of each substrate B in the forward direction X1 coincides with the position (detection position) detected by one of sensors Su, Sr1, Sr2 and Sr3 ("S304_2" in Figure 8 or the "Before positioning operation starts" column in Figure 10).

[0064] As shown in Fig. 5, when the search operation of step S208 is completed, a positioning operation is executed (step S208). In the positioning operation shown in Fig. 9, the board transport control unit 14 performs positioning of the conveyors 21, 22, 23, and 24 in order from the conveyor on the downstream side in the forward direction X1. Therefore, in step S401, of the conveyors 21, 22, 23, and 24, the standby conveyor 24 which is the most downstream in the forward direction X1 is set as the target conveyor.

[0065] In step S402, the board transport control unit 14 determines whether the boundary sensor Sr3 corresponding to the standby conveyor 24, which is the target conveyor, detects board B. If the boundary sensor Sr3 does not detect board B and outputs OFF (if "NO" in step S402), the process proceeds to step S407. On the other hand, if the boundary sensor Sr3 detects board B and outputs ON (if "YES" in step S402), the process proceeds to step S403. In the example "before the positioning operation starts" in FIG. 10, as a result of the search operation, the upstream end of board B in the forward direction X1 on the standby conveyor 24 coincides with the detection position of the boundary sensor Sr3, and the boundary sensor Sr3 detects board B ("YES" in step S402). Therefore, steps S403 to S406 are executed.

[0066] In step S403, the standby conveyor 24, which is the target conveyor, operates in the forward direction X1, and the board B on the standby conveyor 24 moves in the forward direction X1. In step S404, the board transport control unit 14 determines whether the output of the sensor corresponding to the standby conveyor 24, i.e., the boundary sensor Sr3, has changed. In the example of FIG. 10, as the board B moves, the edge of the board B moves away from the boundary sensor Sr3 in the forward direction X1, and the output of the boundary sensor Sr3 changes from ON to OFF ("YES" in step S404). From the timing when the output of the boundary sensor Sr3 changes, the board transport control unit 14 operates the standby conveyor 24, which is the target conveyor, in the forward direction X1 by a specified distance (step S405) and stops the standby conveyor 24 (step S406). As a result, as shown in the "S406" column in FIG. 10, the board B on the standby conveyor 24 is positioned at a position spaced from the boundary sensor Sr3 in the forward direction X1 by the specified distance.

[0067] In step S407, the board transport control unit 14 determines whether the target conveyor is the most upstream conveyor in the forward direction X1, i.e., the standby conveyor 21. In this example, the target conveyor is the standby conveyor 24, not the standby conveyor 21 ("NO" in step S407). Therefore, in step S408, the conveyor one level upstream, i.e., the mounting conveyor 23, is set as the target, and the process returns to step S402.

[0068] In step S402, the board transport control unit 14 determines whether the boundary sensor Sr2 corresponding to the target conveyor, the mounting conveyor 23, detects the board B. In the example "before the positioning operation starts" in Fig. 10, as a result of the search operation, the upstream end of the board B in the forward direction X1 on the mounting conveyor 23 coincides with the detection position of the boundary sensor Sr2, and the boundary sensor Sr2 detects the board B ("YES" in step S402). Therefore, steps S403 to S406 are executed.

[0069] In step S403, the mounting conveyor 23, which is the target conveyor, operates in the forward direction X1, and the board B on the mounting conveyor 23 moves in the forward direction X1. In step S404, the board transfer control unit 14 determines whether the output of the sensor corresponding to the mounting conveyor 23, i.e., the boundary sensor Sr2, has changed. In the example of FIG. 10, as the board B moves, the edge of the board B moves away from the boundary sensor Sr2 in the forward direction X1, and the output of the boundary sensor Sr2 changes from ON to OFF ("YES" in step S404). From the timing when the output of the boundary sensor Sr2 changes, the board transfer control unit 14 operates the mounting conveyor 23, which is the target conveyor, in the forward direction X1 by a specified distance (step S405) and stops the mounting conveyor 23 (step S406). As a result, as shown in the "S406_2" column in FIG. 10, the board B on the mounting conveyor 23 is positioned at a position spaced apart from the boundary sensor Sr2 in the forward direction X1 by the specified distance.

[0070] Incidentally, the board detection unit Ud can be equipped with a positioning sensor Sla that detects the board B supported by the mounting conveyor 23. In a configuration equipped with this positioning sensor Sla, the positioning sensor Sla can be used instead of the boundary sensor Sr2 as the sensor corresponding to the mounting conveyor 23. In other words, the board transport control unit 14 may operate the mounting conveyor 23 by a specified distance from the timing at which it is confirmed in step S404 that the output of the positioning sensor Sla has changed from off to on.

[0071] In step S407, the board transport control unit 14 determines whether the target conveyor is the most upstream conveyor in the forward direction X1, i.e., the standby conveyor 21. In this example, the target conveyor is the standby mounting conveyor 23, not the standby conveyor 21 ("NO" in step S407). Therefore, in step S408, the conveyor one level upstream, i.e., the mounting conveyor 22, is set as the target, and the process returns to step S402.

[0072] In step S402, the board transport control unit 14 determines whether the boundary sensor Sr1 corresponding to the target conveyor, the mounting conveyor 22, detects the board B. In the example of "before the positioning operation starts" in Fig. 10, the corresponding board B is not present, so the boundary sensor Sr2 does not detect the board B ("NO" in step S402). Therefore, the process proceeds to step S407.

[0073] In step S407, the board transport control unit 14 determines whether the target conveyor is the most upstream conveyor in the forward direction X1, i.e., the standby conveyor 21. In this example, the target conveyor is the mounting conveyor 22, not the standby conveyor 21 ("NO" in step S407). Therefore, in step S408, the conveyor one level upstream, i.e., the standby conveyor 21, is set as the target, and the process returns to step S402.

[0074] In step S402, the board transport control unit 14 determines whether the trailing edge sensor Su corresponding to the standby conveyor 21, which is the target conveyor, detects the board B. In the example "before the positioning operation starts" in Fig. 10, as a result of the search operation, the upstream edge of the board B in the forward direction X1 on the standby conveyor 21 coincides with the detection position of the trailing edge sensor Su, and the trailing edge sensor Su detects the board B ("YES" in step S402). Therefore, steps S403 to S406 are executed.

[0075] In step S403, the standby conveyor 21, which is the target conveyor, operates in the forward direction X1, and the board B on the standby conveyor 21 moves in the forward direction X1. In step S404, the board transport control unit 14 determines whether the output of the sensor corresponding to the standby conveyor 21, i.e., the trailing edge sensor Su, has changed. In the example of FIG. 10, as the board B moves, the end of the board B moves away from the trailing edge sensor Su in the forward direction X1, and the output of the trailing edge sensor Su changes from ON to OFF ("YES" in step S404). From the timing when the output of the trailing edge sensor Su changes, the board transport control unit 14 operates the standby conveyor 21, which is the target conveyor, in the forward direction X1 by a specified distance (step S405) and stops the standby conveyor 21 (step S406). As a result, as shown in the "S406_3" column in FIG. 10, the board B on the standby conveyor 21 is positioned at a position spaced apart from the trailing edge sensor Su in the forward direction X1 by the specified distance.

[0076] In step S407, the board transport control unit 14 determines whether the target conveyor is the most upstream conveyor in the forward direction X1, i.e., the standby conveyor 21. In this example, the target conveyor is the standby conveyor 21 ("YES" in step S407). Therefore, the positioning operation in FIG. 9 is completed, and the first preparation in FIG. 5 is completed.

[0077] Returning to Figure 4, the explanation will continue. If the length Lb of the board B is longer than the length Lcw (if "NO" in step S102), then in step S104 it is determined whether the length Lb of the board B is equal to or less than the length Lcm of the mounting conveyors 22, 23, in other words, whether it corresponds to the length Lb2 shown in Figure 3. If the length Lb of the board B is equal to or less than the length Lcm of the mounting conveyors 22, 23 (if "YES" in step S104), then the second preparation in step S105 is executed.

[0078] Figure 11 is a flowchart showing an example of the second preparation performed in response to the remaining substrate in Figure 4, Figure 12 is a diagram showing schematically the operations performed in the second preparation in Figure 11, Figure 13 is a flowchart showing an example of the search operation (section) performed in the second preparation in Figure 12, Figure 14 is a diagram showing schematically the operations performed in the search operation (section) in Figure 13, Figure 15 is a flowchart showing an example of the positioning operation (section) performed in the second preparation in Figure 11, and Figure 16 is a diagram showing schematically the operations performed in the positioning operation (section) in Figure 15.

[0079] 11, the board transport control unit 14 divides the four conveyors 21, 22, 23, and 24 of the board transport unit 2 into multiple sections A1 and A2 so that each of the multiple sections A1 and A2 includes two or more conveyors. In this example, the four conveyors 21, 22, 23, and 24 are divided into two sections A1 and A2, with section A1 including the standby conveyor 21 and the mounting conveyor 22, and section A2 including the mounting conveyor 23 and the standby conveyor 24. Of the boundaries R1, R2, and R3, the board transport control unit 14 particularly treats the boundary R2 between sections A1 and A2 as the "section boundary," and of the boundary sensors Sr1, Sr2, and Sr3 of the board detection unit Ud, the boundary sensor Sr2 that detects board B at the boundary between sections A1 and A2 as the "section boundary sensor."

[0080] The board transport control unit 14 checks the output of the section boundary sensor Sr2 (step S501) and determines whether the output of the section boundary sensor Sr2 is off (step S502). If the output of the section boundary sensor Sr2 is on ("NO" in step S502), step S503 is executed. In the example shown in the "S501" column in FIG. 12, board B is left straddling the mounting conveyor 22 in section A1 and the mounting conveyor 23 in section A2. Therefore, because the section boundary sensor Sr2 outputs on, "NO" is determined in step S502 and the process proceeds to step S503.

[0081] In step S503, the board transport control unit 14 operates the mounting conveyors 22 and 23 upstream and downstream of the section boundary sensor Sr2 that has been confirmed to output on in the forward direction X1. As a result, as shown by the arrow in the "S503" column in Fig. 12, the board B that overlaps the section boundary R2 moves in the forward direction X1. Furthermore, as the mounting conveyor 22 operates in the forward direction X1, the board B that straddles the standby conveyor 21 and the mounting conveyor 22 also moves in the forward direction X1.

[0082] After step S503 is executed, the process returns to step S501. That is, the output of the section boundary sensor Sr2 is checked (step S501), and it is determined whether the output of the section boundary sensor Sr2 is off (step S502). In the example shown in the "S501_2" column in FIG. 6, the board B has retreated from the section boundary R2, and the section boundary sensor Sr2 outputs off ("YES" in step S502). Therefore, the board transport control unit 14 stops all of the conveyors 21, 22, 23, and 24 (step S504).

[0083] By executing step S503 (evacuation operation) in this manner, the board B, which was straddling the mounting conveyor 22 in section A1 and the mounting conveyor 23 in section A2 before the start of the second preparation, is evacuated in the forward direction X1 from the section boundary R2 between sections A1 and A2 ("S501_2" in Figure 12 or the "Before search operation starts" column in Figure 14).

[0084] When steps S501 to S504, including the retraction operation (step S503), are completed, a search operation is performed (step S505). In the search operation (section) shown in FIG. 13, the board transport control unit 14 operates all of the conveyors 21, 22, 23, and 24 in the reverse direction X2 (step S601). This causes the board B supported by the board transport unit 2 to move in the reverse direction X2 (arrow in the "S601" column in FIG. 14). In step S602, the board transport control unit 14 determines whether the conveyors 21 and 22 in section A1 and the conveyors 23 and 24 in section A2 have each moved a predetermined distance. This predetermined distance is set according to the respective lengths of section A1 and section A2. For example, the predetermined distance can be a length Lcmw corresponding to the respective lengths of section A1 and section A2.

[0085] If the conveyors 21, 22 in section A1 and the conveyors 23, 24 in section A2 have not moved a predetermined distance ("NO" in step S602), the board transport control unit 14 determines whether board B has been detected in both sections A1 and A2 (step S603). Here, detecting board B in section A1 means that at least one of the rear end sensor Su provided at the downstream end of section A1 in the reverse direction X2 and the boundary sensor Sr1 included in section A1 has detected board B, and detecting board B in section A2 means that at least one of the section boundary sensor Sr2 corresponding to the section boundary R2 downstream of section A2 in the reverse direction X2 and the boundary sensor Sr3 included in section A2 has detected board B.

[0086] In the example shown in the "S601" column of Figure 14, the boundary sensor Sr1 detects the substrate B in the section A1, but does not detect the substrate B in the section A2 ("NO" in step S603), so the process proceeds to step S604. In step S604, the substrate transport control unit 14 determines whether any of the sensors Su, Sr1, Sr2, and Sr3 outputs an ON signal (an ON output sensor). If no ON output sensor exists ("NO" in step S604), the process returns to step S602.

[0087] On the other hand, if there is an ON output sensor ("YES" in step S604), the board transport control unit 14 stops the conveyor in the section corresponding to the ON output sensor (step S605). Here, the section corresponding to the trailing end sensor Su and boundary sensor Sr1 is section A1, and the conveyors in this section A1 are the standby conveyor 21 and the mounting conveyor 22. Furthermore, the section corresponding to boundary sensor Sr2 and boundary sensor Sr3 is section A2, and the conveyors in this section A2 are the mounting conveyor 23 and the standby conveyor 24. That is, in step S605, board B detected by the ON output sensor is stopped. Following step S605, the process returns to step S602.

[0088] 14, the boundary sensor Sr1 corresponding to section A1 outputs ON, so the standby conveyor 21 and mounting conveyor 22 in section A1 are stopped. On the other hand, the boundary sensors Sr2 and Sr3 corresponding to section A2 output OFF, so the mounting conveyor 23 and standby conveyor 24 in section A2 continue to operate in the reverse direction X2.

[0089] Steps S603 to S605 are The conveyors 21 and 22 in the section A1 and the conveyors 23 and 24 in the section A2 each operate for a predetermined distance ("YES" in step S602, Board B is detected in both sections A1 and A2 (YES in step S603). On the other hand, if any of these conditions is met, then in step S606, all of the conveyors 21, 22, 23 and 24 are stopped, and the search operation in FIG. 13 is completed.

[0090] In the example shown in the "S604" column of FIG. 14, the conveyors 21 and 22 in section A1 and the conveyors 23 and 24 in section A2 have not moved a predetermined distance ("NO" in step S602). Also, board B has not been detected in section A2 ("NO" in step S603). Therefore, steps S604 to S605 are executed in the same manner as described above. As in the example shown in the "S604_2" column of FIG. 14, when the section boundary sensor Sr2 corresponding to section A2 outputs ON ("YES" in step S604), the board transport control unit 14 stops the mounting conveyor 23 and standby conveyor 24 in section A2 corresponding to the section boundary sensor Sr2, thereby stopping board B detected by the section boundary sensor Sr2 (step S605).

[0091] As a result, board B is detected in both sections A1 and A2 (YES in step S603), and all of conveyors 21, 22, 23 and 24 are stopped (step S606), completing the search operation of FIG.

[0092] By executing steps S505, S601 to S606 (search operation) in this manner, each substrate B overlaps with a position (detection position) detected by one of sensors Su, Sr1, Sr2 and Sr3 ("S604_2" in Figure 14 or the "Before positioning operation starts" column in Figure 16).

[0093] As shown in Fig. 11, when the search operation (section) of step S505 is completed, a positioning operation (section) is executed (step S506). In the positioning operation (section) shown in Fig. 15, the substrate transport control unit 14 performs positioning in the sections A1 and A2 in order from the section on the downstream side in the forward direction X1. That is, in step S701, of the sections A1 and A2, the section A2 that is the most downstream in the forward direction X1 is set as the target section.

[0094] In step S702, the substrate transport control unit 14 determines whether a sensor corresponding to the target section A2 detects substrate B. Here, detection of substrate B in the target section A2 is performed based on the outputs of the boundary sensor Sr2 corresponding to the section boundary R2 upstream of the section A2 in the forward direction X1 and the positioning sensor Sla included in the section A2. That is, if at least one of the boundary sensor Sr2 and the positioning sensor Sla outputs an ON signal, then in step S702, substrate B has been detected in the target section A2, i.e., the result is “YES,” and the process proceeds to step S703. On the other hand, if both the boundary sensor Sr2 and the positioning sensor Sla output an OFF signal, then in step S702, substrate B has not been detected in the target section A2, i.e., the result is “NO,” and the process proceeds to step S708. In the example shown in the “Before Search Operation Starts” column of FIG. 16, both the boundary sensor Sr2 and the positioning sensor Sla output an ON signal, so the result is “YES” in step S702 and the process proceeds to step S703.

[0095] In step S703, the substrate transport control unit 14 determines a target position (i.e., a position to be positioned) for the substrate B. This target position is determined according to the outputs of the boundary sensor Sr2 and the positioning sensor Sla corresponding to section A2. Specifically, when the positioning sensor Sla outputs ON, the target position is set to a position that is a specified distance away from the boundary sensor Sr2 in the forward direction X1, with the boundary sensor Sla as the reference. On the other hand, when the positioning sensor Sla outputs OFF, the target position is set to a position that is a specified distance away from the positioning sensor Sla in the forward direction X1, with the positioning sensor Sla as the reference. In the example in the "Before search operation starts" column in FIG. 16, the positioning sensor Sla outputs ON, so the target position is set with the boundary sensor Sr2 as the reference.

[0096] In step S704, the board transport control unit 14 operates the mounting conveyor 23 and standby conveyor 24 in the target section A2 in the forward direction X1. As a result, the board B supported by the mounting conveyor 23 moves in the forward direction X1 (the arrow in the "S704" column in FIG. 16). The board transport control unit 14 also monitors a change in the output of the corresponding sensor, i.e., the boundary sensor Sr2 that was used as the reference for determining the target position in step S703 (step S705). Then, from the timing when the output of the boundary sensor Sr2 changes from ON to OFF, the board transport control unit 14 operates the mounting conveyor 23 and standby conveyor 24 in the target section A2 by a specified distance in the forward direction X1 (step S706), and stops the mounting conveyor 23 and standby conveyor 24 in the target section A2 (step S707). As a result, as shown in the "S707" column in FIG. 16, the substrate B in the section A2 is positioned at a position separated from the boundary sensor Sr2 by the specified distance in the forward direction X1.

[0097] In step S708, the substrate transport control unit 14 determines whether the target section is the most upstream section in the forward direction X1, i.e., section A1. In this example, the target section is section A2, not section A1 ("NO" in step S708). Therefore, in step S709, the next upstream section, i.e., section A1, is set as the target, and the process returns to step S702.

[0098] In step S702, the board transport control unit 14 determines whether a sensor corresponding to the target section A1 detects board B. Here, detection of board B in the target section A1 is performed based on the outputs of the boundary sensor Sr1 included in the target section A1 and the positioning sensor Slb that detects board B supported by the mounting conveyor 22 in the target section A1. That is, if at least one of the boundary sensor Sr1 and the positioning sensor Slb outputs an ON signal, then in step S702, board B is detected in the target section A1, i.e., the result is "YES," and the process proceeds to step S703. On the other hand, if both the boundary sensor Sr1 and the positioning sensor Slb output an OFF signal, then in step S702, board B is not detected in the target section A1, i.e., the result is "NO," and the process proceeds to step S708. In the example shown in the "S706" column of FIG. 16, the boundary sensor Sr1 outputs an ON signal, so the result is "YES" in step S702 and the process proceeds to step S703.

[0099] In step S703, the substrate transport control unit 14 determines a target position (i.e., a position to be positioned) for the substrate B. This target position is determined according to the outputs of the boundary sensor Sr1 and the positioning sensor Slb corresponding to section A1. Specifically, when the positioning sensor Slb outputs ON, a position that is a specified distance away from the boundary sensor Sr1 in the forward direction X1 with the boundary sensor Slb as the reference is set as the target position. On the other hand, when the positioning sensor Slb outputs OFF, a position that is a specified distance away from the positioning sensor Slb in the forward direction X1 with the positioning sensor Slb as the reference is set as the target position. In the example in the column "S706" in FIG. 16, the positioning sensor Slb outputs OFF, so the target position is set with the positioning sensor Slb as the reference.

[0100] In step S704, the board transport control unit 14 operates the standby conveyor 21 and the mounting conveyor 22 in the target section A1 in the forward direction X1. As a result, the board B supported by the standby conveyor 21 and the mounting conveyor 22 moves in the forward direction X1 (arrows in the "S704_2" column in FIG. 16). The board transport control unit 14 also monitors changes in the output of the corresponding sensor, i.e., the positioning sensor Slb that was used as the reference for determining the target position in step S703 (step S705). Then, from the timing when the output of the positioning sensor Slb changes from off to on, the board transport control unit 14 operates the standby conveyor 21 and the mounting conveyor 22 in the target section A1 by a specified distance in the forward direction X1 (step S706), and stops the standby conveyor 21 and the mounting conveyor 22 in the target section A1 (step S707). As a result, as shown in the column "S707_2" in FIG. 16, the substrate B in the section A1 is positioned at a position separated from the positioning sensor Slb by the specified distance in the forward direction X1.

[0101] In step S708, the substrate transport control unit 14 determines whether the target section is the most upstream section in the forward direction X1, i.e., section A1. In this example, the target section is section A1 ("YES" in step S708). Therefore, the positioning operation (section) in FIG. 15 ends, and the second preparation in FIG. 11 ends.

[0102] Returning to Figure 4, the explanation will continue. If the length Lb of the substrate B is longer than the length Lcm (if "NO" in step S104), it is determined in step S106 whether the length Lb of the substrate B is equal to or shorter than the length Lcmw, in other words, whether it corresponds to the length Lb3 shown in Figure 3. If the length Lb of the substrate B is equal to or shorter than the length Lcmw (if "YES" in step S106), the third preparation in step S107 is executed.

[0103] Fig. 17 is a flowchart showing an example of the third preparation performed in response to the remaining substrate in Fig. 4, and Fig. 18 is a diagram schematically showing the operations performed in the third preparation in Fig. 17. The third preparation differs from the first and second preparations described above in that no evacuation operation is performed to evacuate substrate B from boundary R1, R2, or R3. This also applies to the fourth preparation described below. In other words, the substrate transport control unit 14 essentially determines that no evacuation operation is necessary by determining in step S104 that length Lb of substrate B is longer than length Lcm.

[0104] Furthermore, in this third preparation, it is determined whether or not a search operation needs to be performed. That is, if board B has length Lb3 that is the target of the third preparation, components E are mounted on board B that is positioned at a mounting position that straddles mounting conveyors 22 and 23, as shown in the "Lb3" column in Fig. 3. In response to this, in step S801 of the third preparation, board transport control unit 14 checks the output of center boundary sensor Sr2 that corresponds to boundary R2 that overlaps with the mounting position, in other words, the center boundary sensor Sr2 that detects the presence or absence of board B at the mounting position.

[0105] If the output of the central boundary sensor Sr2 is off ("NO" in step S802), the board transport control unit 14 executes the search operation (section) of FIG. 13 (step S802). In this case, for example, as shown in the "Before Search Operation Start" column of FIG. 18, board B is included in at least one of sections A1 and A2 (in the example of FIG. 18, board B is located in each of sections A1 and A2). Furthermore, since the length Lb of board B corresponds to length Lb3, the boundary sensors Sr1 and Sr3 included in sections A1 and A2 detect board B. Therefore, when the conveyors 21, 22, 23, and 24 start moving in the reverse direction X2 in step S601, the boundary sensors Sr1 and Sr3 immediately output "ON" ("YES" in step S604), and the conveyors 21, 22, 23, and 24 in sections A1 and A2 stop (step S605).

[0106] When the search operation (section) is completed in this manner, positioning of board B is performed in step S804. Specifically, the position of board B straddling the standby conveyor 21 and the mounting conveyor 22 (upstream standby position) or the position of board B straddling the mounting conveyor 23 and the standby conveyor 24 (downstream standby position), shown in the "standby" column of "LB3" in Fig. 3, whichever is closer to the position of board B confirmed by the search operation, is set as the target position, and the positioning operation (section) of Fig. 15 is performed (step S804).

[0107] On the other hand, if the output of the central boundary sensor Sr2 is on (if "YES" in step S802), the board transport control unit 14 does not perform the search operation, but instead determines whether the downstream boundary sensor Sr3, which is located downstream of the mounting position in the forward direction X1, is off (step S805). If the downstream boundary sensor Sr3 is off (if "YES" in step S805), the board transport control unit 14 performs the positioning operation (section) of FIG. 15 with the mounting position as the target position (step S806). On the other hand, if the boundary sensor Sr3 is on (if "NO" in step S805), it can be assumed that board B has been left behind during transport after mounting of component E has been completed, so the board transport control unit 14 performs the positioning operation (section) of FIG. 15 with the downstream standby position as the target position (step S807). In this way, the third preparation of FIG. 17 is completed.

[0108] Returning to Figure 4, the explanation continues. If the length Lb of the substrate B is longer than the length Lcmw ("NO" in step S106), the length Lb of the substrate B corresponds to the length Lb4 shown in Figure 3. In this case, the fourth preparation in step S108 is executed.

[0109] Fig. 19 is a flowchart showing an example of the fourth preparation performed in response to the remaining substrate in Fig. 4, and Fig. 20 is a diagram showing schematically the operations performed in the fourth preparation in Fig. 19. The fourth preparation also differs from the first and second preparations described above in that no evacuation operation is performed to evacuate substrate B from boundary R1, R2 or R3.

[0110] In this fourth preparation, the board transport control unit 14 determines whether the downstream boundary sensor Sr3 located downstream of the mounting position in the forward direction X1 is off (step S901). If the downstream boundary sensor Sr3 is off (if "YES" in step S901), the board transport control unit 14 executes the search operation (section) of FIG. 13 (step S902). Furthermore, the board transport control unit 14 executes the positioning operation (section) of FIG. 15 with the mounting position as the target position (step S903). As a result, the board B is positioned at the position shown in the "Mounting Position" column of FIG. 20. On the other hand, if the boundary sensor Sr3 is on (if "NO" in step S901), it can be assumed that the board B has been left behind during transport after the mounting of the component E has been completed. Therefore, the board transport control unit 14 executes the positioning operation (section) of FIG. 15 with the downstream standby position as the target position (step S904). As a result, the board B is positioned at the position shown in the "Downstream Standby Position" column of FIG. 20. Thus, the fourth preparation in FIG. 19 is completed.

[0111] In the embodiment described above, whether or not a retraction operation (steps S203 to S206 or step S503) is required to retract a board B spanning two conveyors (conveyors 21 and 22, conveyors 22 and 23, or conveyors 23 and 24) from a boundary (boundary R1, boundary R2, or boundary R3) is required is determined based on the length Lb of the board B in the board transport direction X (arrangement direction) and the detection result of the board B by the boundary sensor Sr1, Sr2, or Sr3 (steps S102, S104, steps S201 to S202, or steps S501 to S502). Therefore, the retraction operation is performed based on the determination of whether or not the operation is required, and an operation can be performed to retract the board B from the boundary R1, R2, or R3 between the two conveyors 21 and 22, 22 and 23, or 23 and 24. In this way, it is possible to deal with a board B that is left across two adjacent conveyors 21 and 22, 22 and 23, or 23 and 24.

[0112] Furthermore, the control unit 10 (control unit) determines that a retraction operation is necessary when the length Lb of the board B is shorter than the length Lcm, Lcm, or Lcw in the board conveying direction X of the conveyor 22, 23, or 24 that is downstream in the forward direction X1 (first direction) among the two conveyors 21 and 22, 22 and 23, or 23 and 24, and the board B is detected at the boundary R1, R2, or R3 (steps S102 to S105). This allows the board B that has remained across the two conveyors 21 and 22, 22 and 23, or 23 and 24 to be moved to the conveyor 22, 23, or 23 and 24 that is downstream in the forward direction X1 among the two conveyors 21 and 22, 22 and 23, or 23 and 24, and the board B can be retracted from the boundary R1, R2, or R3 between the two conveyors 21 and 22, 22 and 23, or 23 and 24. In this way, it is possible to deal with a board B that is left across two adjacent conveyors 21 and 22, 22 and 23, or 23 and 24.

[0113] The control unit 10 also divides the four conveyors 21, 22, 23, and 24 into multiple sections A1 and A2, each having a length greater than or equal to but less than twice the length Lb of the substrate B in the substrate transport direction X, so that each section A1 and A2 includes two or more conveyors 21, 22, 23, and 24. The control unit 10 then determines that a retraction operation for retracting the substrate B from boundaries R1 and R3 included in the sections A1 and A2 is unnecessary. That is, in the second preparation shown in FIG. 11, the retraction operation is not performed regardless of the outputs of the boundary sensors Sr1 and Sr3 corresponding to the boundaries R1 and R3. Meanwhile, the control unit 10 determines whether a retraction operation for retracting the substrate B from the section boundary R2, which is the boundary R2 sandwiched between two adjacent sections A1 and A2, is necessary based on the detection result of the substrate B by the boundary sensor Sr2 disposed corresponding to the section boundary R2 (steps S501 and S502). This configuration functions effectively when one substrate is supported for each of the sections A1 and A1 (the case of the "Lb2" column in Figure 3). In other words, in such a case, even if the substrate B straddles the boundary R1 or R3 included in the middle of the section A1 or A2, there is no need to retract the substrate B from the boundary R1 or R3. On the other hand, if the substrate B straddles the section boundary R2, which is the boundary R2 sandwiched between two adjacent sections A1 and A2, it is necessary to retract the substrate B from the section boundary R2. In contrast, with this configuration, it is possible to accurately determine whether or not a retraction operation is required.

[0114] Furthermore, when the control unit 10 determines that a retraction operation is necessary, it executes a search operation (steps S208, S505) to search for a conveyor supporting board B from among the conveyors 21, 22, 23, and 24, after executing the retraction operation (steps S206, S503). On the other hand, when the control unit 10 determines that a retraction operation is not necessary, it executes the search operation (steps S208, S505, S803) without executing the retraction operation. With this configuration, the retraction operation (steps S206, S503) is executed depending on whether it is necessary, thereby preventing overdetection of board B during the search operation (steps S208, S505, S803).

[0115] In addition, a trailing edge sensor Su (upstream sensor) is provided to detect board B at the upstream end of conveyors 21, 22, 23, and 24 in forward direction X1. In response to this, control unit 10 determines the presence or absence of board B on conveyors 21, 22, 23, and 24 based on the detection results of board B by boundary sensors Sr1, Sr2, and Sr3 and trailing edge sensor Su when conveyors 21, 22, 23, and 24 are operated in reverse direction X2 (second direction), thereby performing a search operation (steps S303 to S304, steps S603 to S604). With this configuration, board B can be detected by boundary sensors Sr1, Sr2, and Sr3 and trailing edge sensor Su, and the search operation (steps S208, S505, S803) can be performed quickly.

[0116] Furthermore, the control unit 10 executes the search operation (steps S208, S505, S803) by detecting the end of the substrate B on the downstream side in the reverse direction X2 using the boundary sensors Sr1, Sr2, Sr3 and the trailing edge sensor Su. With this configuration, the boundary sensors Sr1, Sr2, Sr3 and the trailing edge sensor Su detect the end of the substrate B, and the search operation (steps S208, S505, S803) can be executed quickly.

[0117] Furthermore, the control unit 10 sequentially carries in a plurality of boards B using the conveyors 21, 22, 23, and 24, and uses the mounting head 31 to mount components E on the plurality of boards B that have been carried in, thereby producing a plurality of boards mounted with components. In response to this, the control unit 10 executes a search operation before the start of or when the production of a plurality of boards mounted with components is interrupted (step S101). With this configuration, it is possible to search for boards B left on the conveyors 21, 22, 23, and 24 before the start of or when the production of boards is interrupted.

[0118] Furthermore, when the length Lb of the board B is longer than the length in the board transport direction X of the conveyor 22, 23, or 24 downstream in the forward direction X1, of the two conveyors 21 and 22, 22 and 23, or 23 and 24, the control unit 10 determines that the retraction operation to retract the board B from the boundary R1, R2, or R3 is unnecessary. In other words, if the determination in step S104, which determines whether the length Lb is equal to or less than the length L cm, is "NO," the retraction operation is not performed. With this configuration, it is possible to accurately determine whether the retraction operation is necessary.

[0119] Furthermore, the length Lcmm between both ends of the two mounting conveyors 22 and 23 in the board transport direction X is longer than the length Lb of the board B, and the board B on which components E are mounted by the mounting head 31 is supported between both ends of the two mounting conveyors 22 and 23. In response to this, the control unit 10 determines whether or not a search operation (step S803) is required to search for the board B remaining on the conveyors 21, 22, 23, and 24, based on the detection result of the board B by the boundary sensor Sr2 (steps S801 to S802). With this configuration, it is possible to accurately determine whether or not the search operation (step S803) is required.

[0120] Furthermore, the two mounting conveyors 22 and 23 are provided with a boundary sensor Sr1 (upstream sensor) that detects the board B on the upstream side in the forward direction X1, and a boundary sensor Sr3 (downstream sensor) that detects the board B on the downstream side in the forward direction X1, for the two mounting conveyors 22 and 23. In response to this, the board transport control unit 14 determines the presence or absence of the board B on the conveyors 21, 22, 23, and 24 based on the detection results of the board B by the boundary sensors Sr1 and Sr3 when the conveyors 21, 22, 23, and 24 are operated in the reverse direction X2 (step S803). With this configuration, the board B can be detected by the boundary sensors Sr1 and Sr3, and the search operation (step S803) can be performed quickly.

[0121] Furthermore, the control unit 10 determines that the search operation (step S803) is unnecessary when the boundary sensor Sr2 detects the substrate B, and determines that the search operation (step S803) is necessary (step S802) when the boundary sensor Sr2 does not detect the substrate B. With this configuration, it is possible to accurately determine whether the search operation (step S803) is necessary.

[0122] Furthermore, the two mounting conveyors 22 and 23 are provided with a boundary sensor Sr3 (downstream sensor) that detects the board B downstream in the forward direction X1. Furthermore, the length Lcmm between the two ends of the two mounting conveyors 22 and 23 in the board transport direction X is longer than the length Lb of the board B, and the board B on which components E are mounted by the mounting head 31 is supported between the two ends of the two mounting conveyors 22 and 23. In response to this, the control unit 10 determines whether or not a search operation (step S902) is required to search for the board B remaining on the conveyors 21, 22, 23, and 24, based on the detection result of the board B by the boundary sensor Sr3 (step S901). With this configuration, it is possible to accurately determine whether or not the search operation (step S902) is required.

[0123] Furthermore, if the boundary sensor Sr3 detects the substrate B ("NO" in step S301), the control unit 10 determines that a search operation is unnecessary, and if the boundary sensor Sr3 does not detect the substrate B ("YES" in step S901), the control unit 10 determines that a search operation is necessary (step S901). With this configuration, it is possible to accurately determine whether a search operation (step S902) is necessary.

[0124] Furthermore, the control unit 10 sequentially carries in a plurality of boards B using the conveyors 21, 22, 23, and 24, and uses the mounting head 31 to mount components E on the plurality of boards B that have been carried in, thereby producing a plurality of component-mounted boards. In response to this, the control unit 10 determines whether a search operation is necessary before the start of or when the production of a plurality of component-mounted boards is interrupted (steps S101, S802, S901). With this configuration, it is possible to search for boards B left on the conveyors 21, 22, 23, and 24 before the start of or when the production of boards is interrupted.

[0125] Furthermore, the control unit 10 performs a retraction operation by operating the two conveyors 21 and 22, 22 and 23, or 23 and 24 in the forward direction X1 until the boundary sensor Sr1, Sr2, or Sr3 no longer detects the board B (steps S206, S503). This configuration retracts the board B left straddling the two conveyors 21 and 22, 22 and 23, or 23 and 24 from the boundary R1, R2, or R3 between the two conveyors 21 and 22, 22 and 23, or 23 and 24. In this way, it is possible to deal with the board B left straddling two adjacent conveyors 21 and 22, 22 and 23, or 23 and 24.

[0126] As described above, in this embodiment, the component mounter 1 corresponds to an example of a "component mounting system" of the present invention, the control unit 10 corresponds to an example of a "control unit" of the present invention, the four conveyors 21, 22, 23, and 24 correspond to an example of the "N conveyors" of the present invention, the mounting head 31 corresponds to an example of a "mounting head" of the present invention, the board B corresponds to an example of a "board" of the present invention, the component E corresponds to an example of a "component" of the present invention, the board transport direction X corresponds to an example of an "arrangement direction" of the present invention, the forward direction X1 corresponds to an example of a "first direction" of the present invention, the reverse direction X2 corresponds to an example of a "second direction" of the present invention, each of the boundary sensors Sr1, Sr2, and Sr3 corresponds to an example of a "boundary sensor" of the present invention, the boundary sensor Sr1 corresponds to an example of an "upstream sensor" of the present invention, the boundary sensor Sr3 corresponds to an example of a "downstream sensor" of the present invention, the rear end sensor Su corresponds to an example of an "upstream sensor" of the present invention, and the positioning sensors Sla and Slb each correspond to an example of a "positioning sensor" of the present invention.

[0127] The present invention is not limited to the above embodiment, and various modifications can be made to the above without departing from the spirit of the present invention. For example, the number N of conveyors provided in the substrate transport unit 2 is not limited to 4, but may be 2 or more.

[0128] Furthermore, the number of component mounters 1 that make up the component mounting system is not limited to 1. For example, the component mounting system may be configured by arranging two component mounters 1 in series.

[0129] Furthermore, the direction in which the substrate B is transported in the retraction operation is not limited to the forward direction X1, but may be the reverse direction X2. Furthermore, when the direction in which the substrate B is transported in the retraction operation is changed, the direction in which the substrate B is transported in each of the search operation and the positioning operation may be changed accordingly.

[0130] 10 and 16 is equipped with a positioning sensor Slb or Sla that detects a board B between both ends of the mounting conveyor 22 or 23 in the forward direction X1. Therefore, the control unit 10 may perform a search operation by determining the presence or absence of a board B on the conveyors 21, 22, 23, or 24 based on the detection result of the positioning sensor Slb or Sla when the conveyors 21, 22, 23, or 24 are operated in the reverse direction X2. For example, in the search operation of FIG. 7, if the positioning sensor Slb or Sla outputs an ON signal in step S304, the mounting conveyor 22 or 23 corresponding to the positioning sensor Slb or Sla may be stopped in step S305. With this configuration, the positioning sensor Slb or Sla can detect the board B, allowing the search operation to be performed quickly.

[0131] At this time, the control unit 10 can execute the search operation by detecting the end of the substrate B on the downstream side in the reverse direction X2 using the positioning sensors Slb and Sla. In this configuration, the positioning sensors Slb and Sla can detect the end of the substrate B, and the search operation can be executed quickly. [Explanation of symbols]

[0132] 1...Component mounting machine (component mounting system) 10...Control unit (control section) 21...Standby conveyor 22...Mounting conveyor 23...Mounting conveyor 24...Standby conveyor 31...Mounting head B...Substrate E...Parts X: Board transport direction (arrangement direction) X1…Forward direction (first direction) X2…Reverse direction (second direction) Sr1: Boundary sensor (upstream sensor) Sr2...Boundary sensor Sr3...Boundary sensor (downstream sensor) Su...Rear end sensor (upstream sensor) Sla...positioning sensor Slb...positioning sensor

Claims

1. N conveyors (N is an integer of 2 or more) arranged in a predetermined arrangement direction and configured to transport substrates in a first direction parallel to the arrangement direction and a second direction opposite to the first direction; a mounting head that mounts components onto the board supported by the conveyor; a boundary sensor provided corresponding to a boundary between two adjacent conveyors and configured to detect the substrate at the boundary; a control unit that determines whether or not a retraction operation is required to retract the substrate straddling the two conveyors from the boundary by operating the two conveyors in the first direction to transport the substrate in the first direction, based on the length of the substrate in the arrangement direction and the detection result of the substrate by the boundary sensor; A component mounting system comprising:

2. 2. The component mounting system according to claim 1, wherein the control unit determines that the retreat operation is necessary when the length of the board in the arrangement direction is shorter than the length of the conveyor downstream in the first direction of the two conveyors and the boundary sensor detects the board.

3. N is 4 or more, The control unit divides the N conveyors into a plurality of sections, each having a length greater than or equal to 1 time but less than 2 times the length of the board in the arrangement direction, so that each section includes two or more conveyors, and determines that the evacuation operation to evacuate the board from the boundary included in the section is unnecessary, while determining whether or not the evacuation operation to evacuate the board from the section boundary, which is the boundary between two adjacent sections, is necessary based on the detection result of the board by the boundary sensor arranged corresponding to the section boundary.

4. 4. A component mounting system as described in any one of claims 1 to 3, wherein, when the control unit determines that the evacuation operation is necessary, it performs a search operation to search for a conveyor supporting the board from among the N conveyors after performing the evacuation operation, whereas, when it determines that the evacuation operation is unnecessary, it performs the search operation without performing the evacuation operation.

5. further comprising an upstream sensor for detecting the substrate at an upstream end of the N conveyors in the first direction; The component mounting system of claim 4, wherein the control unit performs the search operation by determining whether or not the substrate is present on the N conveyors based on the detection results of the substrate from the boundary sensor and the upstream sensor when the N conveyors are operated in the second direction.

6. The component mounting system according to claim 5 , wherein the control unit executes the search operation by detecting an end of the board on the downstream side in the second direction by the boundary sensor or the upstream sensor.

7. a positioning sensor for detecting the substrate between both ends of the conveyor in the first direction; The component mounting system of claim 4, wherein the control unit performs the search operation by determining whether or not the substrate is present on the N conveyors based on the detection results of the substrate by the positioning sensor when the N conveyors are operated in the second direction.

8. The component mounting system according to claim 7 , wherein the control unit executes the search operation by detecting an end of the board on a downstream side in the second direction with the positioning sensor.

9. the control unit sequentially carries in a plurality of boards using the N conveyors, and mounts the components on the plurality of boards carried in using the mounting heads, thereby producing a plurality of component-mounted boards; The component mounting system according to claim 4 , wherein the control unit executes the search operation before the start of or when the production of the plurality of component-mounted boards is interrupted.

10. The component mounting system of claim 1, wherein the control unit determines that the evacuation operation of evacuating the board from the boundary is unnecessary when the length of the board in the arrangement direction is longer than the length of the conveyor downstream in the first direction of the two conveyors.

11. a length between both ends of the two conveyors in the arrangement direction is longer than a length of the board, and the board on which the components are mounted by the mounting head is supported between both ends of the two conveyors; The component mounting system according to claim 10 , wherein the control unit determines whether or not a search operation for searching for the boards left on the N conveyors is necessary based on a detection result of the boards by the boundary sensor.

12. an upstream sensor that detects the substrate on the upstream side in the first direction with respect to the two conveyors; a downstream sensor that detects the substrate downstream in the first direction with respect to the two conveyors; Furthermore, The component mounting system of claim 11, wherein the control unit performs the search operation by determining whether or not the substrate is present on the N conveyors based on the detection results of the substrate from each of the upstream sensor and the downstream sensor when the N conveyors are operated in the second direction.

13. The component mounting system of claim 11, wherein the control unit determines that the search operation is unnecessary when the boundary sensor detects the board, and determines that the search operation is necessary when the boundary sensor does not detect the board.

14. a downstream sensor for detecting the substrate downstream in the first direction with respect to the two conveyors; a length between both ends of the two conveyors in the arrangement direction is longer than a length of the board, and the board on which the components are mounted by the mounting head is supported between both ends of the two conveyors; The component mounting system according to claim 10 , wherein the control unit determines whether or not a search operation for searching for the boards left on the N conveyors is necessary based on a detection result of the boards by the downstream sensor.

15. The component mounting system of claim 14, wherein the control unit determines that the search operation is unnecessary when the downstream sensor detects the substrate, and determines that the search operation is necessary when the downstream sensor does not detect the substrate.

16. the control unit sequentially carries in a plurality of boards using the N conveyors, and mounts the components on the plurality of boards carried in using the mounting heads, thereby producing a plurality of component-mounted boards; The component mounting system according to claim 11 , wherein the control unit determines whether the search operation is necessary before production of the plurality of component-mounted boards is started or when the production is interrupted.

17. The component mounting system according to claim 1 , wherein the control unit executes the retraction operation by operating the two conveyors in the first direction until the boundary sensor no longer detects the board.

18. a step of determining whether or not a retraction operation is required to retract the substrate from a boundary between two adjacent conveyors in N conveyors (N is an integer of 2 or more) that are arranged in a predetermined arrangement direction and transport the substrate in a first direction parallel to the arrangement direction and a second direction opposite to the first direction; a step of executing the evacuation operation when it is determined that the evacuation operation is necessary; Equipped with A substrate transport control method in which the need for the retraction operation is determined based on the detection result of the substrate by a boundary sensor that is provided corresponding to the boundary between two adjacent conveyors and detects the substrate at the boundary, and the length of the substrate in the arrangement direction.

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