Transport device, transport method, and substrate processing machine

Abstract

To provide a technology capable of accurately positioning an object to be conveyed at a desired position.SOLUTION: A conveyance device conveys an object to be conveyed placed on an upper surface of a belt. The conveyance device includes a motor that drives the belt, a stopper that is provided at a predetermined position on the belt and regulates a movement of the object to be conveyed in a conveyance direction, a movement device that moves the stopper to an operation position where the movement of the object to be conveyed can be regulated and a retreat position where the movement of the object to be conveyed cannot be regulated, and a control device that controls driving of the motor. The control device stops a drive of the belt by stopping a current supply to the motor when the object to be conveyed comes into contact with the stopper when the stopper is at the operation position. The movement device moves the stopper from the operation position to the retreat position after the current supply to the motor is stopped.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a transport device, a transport method, and a board processing machine. [Background technology]

[0002] Patent Document 1 discloses a board stopping device that places and transports a circuit board on the upper surface of a belt driven by a motor and stops the circuit board at a predetermined position. In this device, when the downstream end of the circuit board being transported by the belt approaches a stopper, the supply of current to the motor is stopped. When the supply of current to the motor is stopped, the belt moves due to rotation caused by the inertia of the motor until the circuit board abuts against the stopper. When the circuit board abuts against the stopper, the movement of the belt is stopped and the circuit board can be stopped at a predetermined position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-30704 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, the supply of current to the motor is stopped before the circuit board abuts against the stopper. As a result, the rotation of the motor may stop due to inertia before the circuit board abuts against the stopper, and the circuit board cannot be stopped at an appropriate position. This specification provides a technology that can accurately position a transported object at a desired position. [Means for solving the problem]

[0005] The conveying device disclosed in this specification conveys an object placed on the upper surface of a belt. The conveying device includes a motor that drives the belt, a stopper provided at a predetermined position on the belt to restrict movement of the object in the conveying direction, a moving device that moves the stopper to an active position where the stopper can restrict movement of the object and a retracted position where the stopper cannot restrict movement of the object, and a control device that controls the driving of the motor. When the object abuts against the stopper while the stopper is in the active position, the control device stops the driving of the belt by stopping the supply of current to the motor. After the supply of current to the motor is stopped, the moving device moves the stopper from the active position to the retracted position.

[0006] In the above-described conveying device, when the stopper is positioned in the operating position and the conveyed object contacts it, the current supply to the motor is stopped. Even after the current supply to the motor is stopped, the belt may continue to be pulled by the motor's inertia, causing the belt to move. When both the upstream and downstream belts of the stopper move, the stopper restricts the movement of the conveyed object. Therefore, even if the stopper is moved to the retracted position after the motor rotation stops, the relative position of the conveyed object does not change. Here, for example, if the conveyed object is heavy, only the belt downstream of the stopper may be pulled. However, since the current supply to the motor is stopped, when the motor rotation stops, the belt tension causes the motor to rotate in the reverse direction, restoring the belt to its original length. In other words, because the current supply to the motor is stopped and the motor is de-energized, the motor rotates in the reverse direction, releasing the tension. Therefore, even if the stopper is moved from the operating position to the retracted position, the belt does not move, and the relative position of the conveyed object does not change. In this way, in the above-described conveying device, the current supply to the motor is stopped when the conveyed object abuts against the stopper, so that the conveyed object can be positioned at a desired position with high precision.

[0007] This specification also discloses a method for transporting a transported object. In the transport method disclosed in this specification, the transported object is transported by a transport device including a belt on which the transported object is placed, a motor for driving the belt, a stopper provided at a predetermined position on the belt to restrict movement of the transported object in a transport direction, and a moving device for moving the stopper to an operative position where the stopper can restrict movement of the transported object and a retracted position where the stopper cannot restrict movement of the transported object. The transport method includes the steps of: stopping the supply of current to the motor to stop driving the belt when the transported object abuts against the stopper when the stopper is in the operative position; and moving the stopper from the operative position to the retracted position after the supply of current to the motor is stopped.

[0008] This specification also discloses a board processing machine that includes a conveying device that conveys a circuit board placed on the upper surface of a belt, and that performs a predetermined process on the circuit board conveyed to a predetermined position. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a screen printing machine according to an embodiment. [Figure 2] FIG. 2 is a top view showing a configuration including a conveying device of the screen printing machine according to the embodiment. [Figure 3] FIG. [Figure 4] 4 is a flowchart showing a process executed by the screen printing machine of the embodiment. [Figure 5] FIG. 10 is a diagram for explaining an example of the operation of the transport device. [Figure 6] FIG. 10 is a diagram for explaining an example of the operation of the transport device. [Figure 7] FIG. 10 is a diagram for explaining another example of the operation of the transport device. DETAILED DESCRIPTION OF THE INVENTION

[0010] The main features of the embodiments described below are listed below. Note that the technical elements described below are independent technical elements that exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

[0011] In one embodiment of the present technology, the control device may further include a detection device that detects whether the transported object has come into contact with the stopper. When the stopper is located at the operating position, the control device may stop supplying current to the motor when the detection device detects that the transported object has come into contact with the stopper.

[0012] In this configuration, the current supply to the motor is stopped after the transported object comes into contact with the stopper, so the transported object can be stopped more accurately at a desired position.

[0013] In one embodiment of the present technology, the movement device may move the stopper from the operating position to the retracted position after a predetermined time has elapsed since current supply to the motor was stopped.

[0014] In this configuration, even if tension is applied to the belt due to the inertia of the motor, waiting for a predetermined period of time ensures that the belt has time to return to its original length.

[0015] In one embodiment of the present technology, when the transported object abuts the stopper, the control device may stop the supply of current to the motor if the weight of the transported object is greater than a predetermined threshold, or may stop the rotation of the motor while supplying current to the motor if the weight of the transported object is less than the predetermined threshold.

[0016] When the conveyed object contacts the stopper, the stopper restricts the movement of the conveyed object. When the conveyed object is relatively heavy, the frictional force between the belt and the conveyed object is relatively large. Therefore, only the belt downstream of the stopper is pulled. In the above configuration, when the weight of the conveyed object is greater than a predetermined threshold, the current supply to the motor is stopped and the motor is allowed to rotate in the reverse direction. This allows the motor's rotational position to be unfixed, and the motor rotates in a direction that releases the tension applied to the belt (i.e., the motor rotates in the reverse direction). On the other hand, when the conveyed object is relatively light, the frictional force between the belt and the conveyed object is relatively small. Therefore, the entire belt moves, and tension is less likely to be applied to the belt downstream of the stopper. Therefore, even if the motor rotation is stopped while current is being supplied to the motor (i.e., even if the motor is controlled so that its rotational position is fixed), the conveyed object can be accurately positioned at the desired position. Furthermore, because the motor rotation is stopped while current is being supplied to the motor, the motor can be quickly started when it is restarted.

[0017] (Example) A transfer device 10 according to an embodiment will now be described with reference to the drawings. The transfer device 10 is a device that transfers a substrate C. As shown in FIG. 1, the transfer device 10 is provided in a screen printing machine 100. The screen printing machine 100 is a device that screen-prints cream solder onto a substrate C. The screen printing machine 100 is installed alongside other board working machines, such as a component mounting machine that mounts components on the substrate C, a board inspection machine that inspects various conditions of the substrate C, and a reflow furnace that heats the substrate C to reflow solder the components, to form a series of mounting lines. The mounting line is provided with a production management computer (not shown) that controls the operations of these board working machines.

[0018] 1, the screen printing machine 100 includes a control device 20, an interface device 22, a substrate holding device 24, an imaging device 26, a screen mask 28, and a squeegee device 30. The screen printing machine 100 receives a substrate C from the upstream side of a mounting line, screen-prints a desired pattern of cream solder on the substrate C, and then sends the substrate C downstream of the mounting line. In the following description, the transport direction of the substrate C is defined as the X direction, the direction perpendicular to the X direction in a horizontal plane is defined as the Y direction, and the direction perpendicular to the X and Y directions is defined as the Z direction.

[0019] The control device 20 is capable of communicating with the production management computer. The control device 20 controls the operation of each component of the screen printing machine 100 in accordance with instructions from the production management computer. The control device 20 also transmits data indicating the status of the solder printing work in the screen printing machine 100 to the production management computer.

[0020] The interface device 22 presents the setting status and working status of the screen printing machine 100 to the operator via a monitor or the like, and also receives various inputs from the operator via switches or the like.

[0021] The substrate holding device 24 includes a transfer device 10 , a lifting mechanism 46 , a clamping mechanism 50 , and a support mechanism 52 .

[0022] The lifting mechanism 46 is fixed to the base of the screen printing machine 100. The lifting mechanism 46 is configured to be movable in the Z direction relative to the base of the screen printing machine 100 by being driven by an actuator (not shown).

[0023] The transport device 10, clamping mechanism 50, and support mechanism 52 are supported by the lifting mechanism 46. The clamping mechanism 50 can clamp the substrate C from both ends in the Y direction and hold the substrate C at a desired width. The support mechanism 52 can support the substrate C from the underside by abutting the tips of multiple support pins 56 against the underside of the substrate C held by the clamping mechanism 50. The configuration of the transport device 10 will be described later.

[0024] The imaging device 26 includes an XY-direction moving mechanism 60, a substrate imaging device 62, and a mask imaging device 64. The XY-direction moving mechanism 60 is capable of moving in the X and Y directions relative to the base of the screen printing machine 100 by driving an actuator (not shown). The substrate imaging device 62 and the mask imaging device 64 are held by the XY-direction moving mechanism 60. The substrate imaging device 62 includes lighting and a camera for imaging the substrate C, and images the top surface of the substrate C. The mask imaging device 64 includes lighting and a camera for imaging the screen mask 28, and images the bottom surface of the screen mask 28.

[0025] The screen mask 28 is a rectangular metal plate-like member, and its four sides are supported by a mask support frame 66, whose position is fixed relative to the base of the screen printing machine 100. An opening corresponding to the pattern of cream solder to be printed on the substrate C is formed in the center of the screen mask 28. Hereinafter, this opening will also be referred to as the printing pattern.

[0026] The squeegee device 30 includes a Y-direction movement mechanism 70, an X-direction movement mechanism 72, a squeegee head 74, and squeegees 76a and 76b.

[0027] The Y-direction movement mechanism 70 is supported on a base of the screen printing machine 100. The Y-direction movement mechanism 70 is configured to be movable in the Y direction relative to the base of the screen printing machine 100 by driving an actuator (not shown).

[0028] The X-direction moving mechanism 72 is supported by the Y-direction moving mechanism 70. The X-direction moving mechanism 72 is configured to be movable in the X direction relative to the Y-direction moving mechanism 70 by being driven by an actuator (not shown).

[0029] The squeegee head 74 is supported by a Y-direction movement mechanism 70. The squeegee head 74 is configured to be movable in the Z direction relative to the Y-direction movement mechanism 70 by being driven by an actuator (not shown).

[0030] The squeegees 76a and 76b are supported by the squeegee head 74. The squeegees 76a and 76b are configured to be tiltable relative to the squeegee head 74 by the drive of a servo motor (not shown). The squeegees 76a and 76b squeeze cream solder, which is supplied from a solder supply device (not shown) to the upper surface of the screen mask 28, onto the print pattern.

[0031] As shown in FIG. 2, the screen printing machine 100 further includes a carry-in device 80 and an unloading device 82. The carry-in device 80 includes a pair of conveyor belts 84 arranged along the X direction and a servo motor (not shown) that drives each conveyor belt 84. The carry-in device 80 receives the substrate C sent from the substrate transfer device T1 located upstream of the screen printing machine 100 and sends the substrate C to the transfer device 10 of the substrate holding device 24. The unloading device 82 includes a pair of conveyor belts 86 arranged along the X direction and a servo motor (not shown) that drives each conveyor belt 86. The unloading device 82 receives the substrate C sent from the transfer device 10 of the substrate holding device 24 and sends it to the substrate transfer device T2 located downstream of the screen printing machine 100. The spacing between the pair of conveyor belts 84 of the carry-in device 80 and the spacing between the pair of conveyor belts 86 of the unloading device 82 can be adjusted according to the size of the substrate C to be transported.

[0032] 2 and 3, the transport device 10 includes a pair of conveyor belts 102 (hereinafter referred to as belts 102), a pair of belt guides 103, a drive shaft 104, a plurality of driven shafts 106, a motor 108, a stopper 110, a moving device 112, and a detecting device 114. The transport device 10 places both ends of the substrate C in the Y direction on the upper surfaces of the pair of belts 102, and transports the substrate C in the transport direction (X direction).

[0033] The pair of belts 102 are arranged along the X direction. The pair of belts 102 receive the substrates C sent from the carry-in device 80 and transport them toward the carry-out device 82. The pair of belts 102 are each supported by a pair of belt guides 103. As shown in FIG. 3, each belt 102 is stretched between a drive shaft 104 and a plurality of driven shafts 106. Note that a driven shaft (not shown) is also provided upstream of the transport device 10, and each belt 102 is formed in a ring shape. The belts 102 are made of, for example, resin, and are configured to be expandable and contractible according to the tension applied thereto. The distance between the pair of belt guides 103 (i.e., the distance between the pair of belts 102) is adjustable according to the size of the substrates C to be transported.

[0034] The motor 108 is coupled to the drive shaft 104. The motor 108 drives the pair of belts 102 to rotate. That is, when the motor 108 rotates, the drive shaft 104 rotates, and each of the belts 102 rotates. The motor 108 is, for example, a servo motor. Note that the motor 108 may also be a feedback-controllable motor, such as a stepping motor.

[0035] As shown in FIG. 2, the stopper 110 is provided at a predetermined position P (see FIG. 3, etc.) in the transport direction of the substrate C, within a range spanning the pair of belts 102. The stopper 110 is a member that restricts movement of the substrate C in the transport direction. The stopper 110 is supported by a moving device 112. The stopper 110 moves together with the moving device 112 when the moving device 112 is driven by an actuator (not shown), and is configured to be movable between an operating position A and a retracted position R, as shown in FIG. 3. The operating position A is a position where movement of the substrate C in the transport direction can be restricted (i.e., the substrate C cannot pass through the space between the stopper 110 and the belts 102). The retracted position R is a position where movement of the substrate C in the transport direction cannot be restricted (i.e., the substrate C can pass through the space between the stopper 110 and the belts 102). Furthermore, the predetermined position P is set so that when the downstream end of the substrate C is located at the predetermined position P, the substrate C is positioned in the X direction corresponding to the printing pattern of the screen mask 28. Note that, although FIG. 3 shows the retracted position R of the stopper 110 as being above the operating position A, in reality, the retracted position R is set to a position where it does not interfere with other components (for example, the screen mask 28 or the imaging device 26).

[0036] The detection device 114 detects whether the substrate C being transported has come into contact with the stopper 110. The detection device 114 is, for example, a sensor that measures the distance to an object using laser light. As shown in FIG. 3, the detection device 114 irradiates laser light along the contact surface (position P) of the stopper 110 with the substrate C and receives the reflected light to detect whether the substrate C is present (i.e., whether the substrate C has come into contact with the stopper 110). The detection result of the detection device 114 is input to the control device 20. Note that the detection device 114 may have any configuration as long as it is a device that can detect that the substrate C has come into contact with the stopper 110.

[0037] Next, with reference to Fig. 4, the processing executed by the control device 20 of the screen printing machine 100 will be described. First, in S10, the control device 20 determines whether or not the substrate C has been carried in. That is, the control device 20 determines whether or not the substrate C has been sent from the upstream substrate transport device T1. When the substrate C has been sent from the substrate transport device T1, the control device 20 drives the carry-in device 80 to receive the substrate C. Then, the control device 20 drives the lifting mechanism 46 so that the transport device 10 is in a position where it can receive the substrate C from the carry-in device 80.

[0038] In S12, the control device 20 drives the moving device 112 to move the stopper 110 from the retracted position R to the operating position A. That is, the control device 20 brings the lower surface of the stopper 110 close to the upper surface of the belt 102. Then, in S14, the control device 20 drives the motor of the carry-in device 80 and the motor 108 of the transport device 10 to transfer the substrate C from the carry-in device 80 to the transport device 10. Once the substrate C has been transferred to the transport device 10, the control device 20 continues to drive the motor 108 to rotate the belt 102, thereby transporting the substrate C in the X direction.

[0039] In S16, the control device 20 determines whether or not the substrate C being transported has come into contact with the stopper 110. The control device 20 determines whether or not the substrate C has come into contact with the stopper 110 based on the detection result of the detection device 114.

[0040] When the control device 20 detects that the substrate C has come into contact with the stopper 110 (YES in S16), it determines in S18 whether the weight of the substrate C is greater than a predetermined threshold. The manner in which the control device 20 determines the weight of the substrate C is not particularly limited. For example, the control device 20 may receive information indicating the weight of the substrate C from a production management computer that stores information about the substrates C being produced, or a sensor that measures the weight of the substrate C may be provided in the transport device 10. If the control device 20 determines that the weight of the substrate C is greater than the predetermined threshold (YES in S18), it proceeds to S20, and if the control device 20 determines that the weight of the substrate C is less than the predetermined threshold (NO in S18), it proceeds to S24.

[0041] In S20, the control device 20 stops the supply of current to the motor 108. Specifically, it stops the excitation current supplied to the coil (not shown) of the motor 108. As a result, the torque of the motor 108 becomes zero (the magnetic field generated from the coil becomes zero), and the rotation of the motor 108 stops. Then, in S22, the control device 20 determines whether a predetermined time has elapsed since the supply of current to the motor 108 was stopped. The predetermined time is not particularly limited, but can be, for example, several seconds. If the control device 20 determines that the predetermined time has elapsed (YES in S22), the process proceeds to S26.

[0042] On the other hand, in S24, the control device 20 stops the rotation of the motor 108 while maintaining the supply of current to the motor 108. Specifically, the control device 20 stops the rotation of the motor 108 while an excitation current is being supplied to the coil of the motor 108 (a state in which the motor 108 can output torque (a state in which a magnetic field is generated from the coil)). This causes the motor 108 to be controlled to a servo-lock state (a position-controlled state).

[0043] Thereafter, in S26, the control device 20 drives the moving device 112 to move the stopper 110 from the operating position A to the retracted position R. That is, the control device 20 separates the lower surface of the stopper 110 from the upper surface of the belt 102. As a result, the substrate C is positioned in the X direction at a position corresponding to the printing pattern of the screen mask 28.

[0044] After moving the stopper 110 to the retracted position R, the control device 20 executes the printing process in S28. In the printing process, first, the control device 20 drives the clamp mechanism 50 and the support mechanism 52 to hold the substrate C. Next, the control device 20 drives the imaging device 26 to capture images of an alignment mark (not shown) provided on the upper surface of the substrate C and an alignment mark (not shown) provided on the lower surface of the screen mask 28, and detects misalignment between them through image processing. When the misalignment is detected, the control device 20 fine-tunes the position of the substrate C. Then, the control device 20 drives the lifting mechanism 46 to bring the substrate C into contact with the lower surface of the screen mask 28.

[0045] The control device 20 also supplies cream solder to the upper surface of the screen mask 28 using a solder supply device (not shown). When the substrate C abuts against the lower surface of the screen mask 28 and cream solder is supplied to the upper surface of the screen mask 28, the control device 20 drives the squeegee head 74 to bring one squeegee (e.g., squeegee 76a) into contact with the upper surface of the screen mask 28, and then drives the Y-direction movement mechanism 70 and the X-direction movement mechanism 72 to perform squeegeeing relative to the printing pattern on the screen mask 28. As a result, solder is printed in a pattern corresponding to the printing pattern on the substrate C, which is held in contact with the lower surface of the screen mask 28.

[0046] When printing of the solder on the substrate C is complete, the control device 20 drives the Y-direction movement mechanism 70, the X-direction movement mechanism 72, and the squeegee head 74 to return the squeegee device 30 to the standby position. The control device 20 also drives the lifting mechanism 46, the clamping mechanism 50, and the support mechanism 52 to transfer the substrate C back to the transport device 10. Furthermore, the control device 20 drives the lifting mechanism 46 so that the transport device 10 is in a position where it can transfer the substrate C to the carry-out device 82. This completes the printing process.

[0047] When the printing process is completed, in S30, the control device 20 drives the motor 108 of the transport device 10 and the motor of the carry-out device 82 to transfer the substrate C from the transport device 10 to the carry-out device 82. Thereafter, the control device 20 drives the carry-out device 82 to send out the substrate C to the downstream substrate transport device T2. After executing S30, the control device 20 ends the series of processes.

[0048] In the above-described embodiment, if the weight of the substrate C being transported is greater than the threshold value (YES in S18), and the substrate C abuts against the stopper 110 (YES in S16), the control device 20 stops the current supply to the motor 108 (S20). That is, the control device 20 stops the excitation current to the motor 108. FIG. 5 shows the state immediately after the control device 20 stops the current supply to the motor 108. As indicated by arrow 200 in FIG. 5, the motor 108 may continue to rotate due to inertia even after the current supply to the motor 108 is stopped. Furthermore, after the control device 20 detects that the substrate C has abutted against the stopper 110, it outputs a command to stop the current supply to the motor 108. Therefore, the motor 108 may rotate even during the short time between the detection and the output of the command. Therefore, these rotations pull the belt 102 in the rotation direction of the motor 108. Here, the movement of the substrate C is restricted by the stopper 110. Furthermore, because the substrate C is relatively heavy, the frictional force generated between the substrate C and the belt 102 is relatively large. Therefore, even if the belt 102 is pulled, no slippage occurs between the substrate C and the belt 102, and the belt 102 upstream of the predetermined position P does not move. As a result, as indicated by arrow 202, tension corresponding to the rotation angle due to the inertia of the motor 108 is applied to the belt 102 located between the predetermined position P and the motor 108, causing the belt 102 to elongate. If the rotation of the motor 108 is stopped without stopping the excitation current to the motor 108, the stopped position (angle) of the motor 108 is maintained. That is, a torque is generated in the motor 108 that maintains the angle of the motor 108 against the tension of the belt 102. If the stopper 110 is moved from the operating position A to the retracted position R in this state, the tension is released while the angle of the motor 108 is fixed, and the belt 102 returns to its original length. As a result, the substrate C moves in the conveying direction by the length of the elongated belt 102. However, in this embodiment, when the substrate C is relatively heavy, the excitation current to the motor 108 is stopped, and the angle of the motor 108 is not fixed. Therefore, after the rotation of the motor 108 occurs due to the inertia, the motor 108 rotates in the reverse direction due to the tension applied to the belt 102, as shown by arrow 204 in FIG. 6, and the tension applied to the belt 102 is released.Therefore, while the stopper 110 is in the operating position A, the belt 102 returns to its original length, as indicated by the arrow 206. In this embodiment, the stopper 110 is moved to the retracted position R in this state, so that the substrate C does not move even after the restriction on the movement of the substrate C is released, and the substrate C can be accurately positioned at the desired position. Furthermore, after the supply of current to the motor 108 is stopped (S20), a predetermined time is waited before the stopper 110 is moved to the retracted position R (YES in S22), so that time is secured for the belt 102 to return to its original length.

[0049] On the other hand, if the weight of the substrate C being transported is smaller than the threshold value (NO in S18), when the substrate C abuts against the stopper 110 (YES in S16), the control device 20 maintains the supply of current to the motor 108 and stops the rotation of the motor 108 (S20). That is, the control device 20 controls the motor 108 to a servo-lock state. FIG. 7 shows the state immediately after the control device 20 outputs a command to maintain the supply of current to the motor 108 and stop the rotation of the motor 108. As indicated by arrow 208 in FIG. 7, the motor 108 may continue to rotate due to inertia even after the command to stop the rotation of the motor 108 is output. Furthermore, since the control device 20 outputs a command to stop the rotation of the motor 108 after detecting that the substrate C has abutted against the stopper 110, the motor 108 may continue to rotate even during the short time between the detection and the output of the command. Therefore, these rotations pull the belt 102 in the rotation direction of the motor 108. In the situation shown in FIG. 7, the movement of the substrate C is restricted by the stopper 110, but because the substrate C is relatively light, the frictional force generated between the substrate C and the belt 102 is relatively small. Therefore, when the belt 102 is pulled, slippage occurs between the substrate C and the belt 102, and as shown by arrow 210, the entire belt 102 (both the upstream and downstream sides of the predetermined position P) moves in response to rotation due to the inertia of the motor 108. In this way, when the substrate C is relatively light, the above-mentioned tension is unlikely to be applied to the belt 102, and even if the motor 108 is controlled to generate torque to maintain its stop position (angle), the substrate C can be accurately positioned at the desired position. Furthermore, because the supply of excitation current is not stopped, the motor 108 can be started quickly when the driving of the motor 108 is resumed (S30).

[0050] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Modifications of the above examples are listed below.

[0051] 4, steps S18 and S22 do not have to be executed. That is, after detecting that the substrate C has come into contact with the stopper 110 (S16), the control device 20 may immediately stop the supply of current to the motor 108 (S20) and move the stopper 110 from the operating position A to the retracted position R (S26).

[0052] In the above-described embodiment, in S16, the detection device 114 detects whether the substrate C has come into contact with the stopper 110. Alternatively, the supply of current to the motor 108 may be stopped (S20) after a predetermined period of time has elapsed since the substrate C was loaded into the transport device 10 (YES in S10). The predetermined period of time may be set by calculating in advance the time from when the substrate C was loaded until it reached the stopper 110, depending on the rotation speed of the motor 108.

[0053] Furthermore, in the above-described embodiment, the case where the conveying device 10 is provided in the screen printing machine 100 has been described, but the conveying device 10 disclosed in this specification may be provided in other board working machines, such as a component mounter that mounts components on a board C or a board inspection machine that inspects the condition of the board C. Furthermore, the objects conveyed by the conveying device 10 are not limited to boards. The technology disclosed in this specification can be applied to any object that is conveyed by a belt and that needs to be positioned in an appropriate position.

[0054] The technical elements described in this specification or drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings simultaneously achieve multiple objectives, and achieving one of those objectives is itself technically useful. [Explanation of symbols]

[0055] 10:Transportation device 20: Control device 100: Screen printing machine 102: Conveyor belt 103: Belt guide 104: Drive shaft 106: Driven axis 108: Motor 110: Stopper 112: Mobile device 114:Detection device

Claims

1. A conveying device that conveys an object placed on an upper surface of a belt, a motor that drives the belt; a stopper provided at a predetermined position on the belt to restrict movement of the conveyed object in the conveying direction; a moving device that moves the stopper to an operating position where the stopper can restrict movement of the transported object and to a retracted position where the stopper cannot restrict movement of the transported object; a control device for controlling the driving of the motor; It is equipped with When the stopper is positioned at the operating position and the transported object abuts against the stopper, the control device When the weight of the conveyed object to be conveyed is such that slippage does not occur between the conveyed object and the belt when the motor is rotated and pulled by supplying current to the motor after the conveyed object has contacted the stopper, the supply of current to the motor is stopped to stop the rotation of the motor, When the weight of the conveyed object to be conveyed is such that slippage occurs between the conveyed object and the belt when the motor is rotated and pulled by supplying current to the motor after the conveyed object has contacted the stopper, the rotation of the motor is stopped while current is being supplied to the motor, the moving device moves the stopper from the operating position to the retracted position after the rotation of the motor is stopped. Conveying device.

2. The transport device further includes a detection device for detecting whether the transported object has come into contact with the stopper, 2. The conveying device according to claim 1, wherein the control device stops rotation of the motor when the detection device detects that the conveyed object has come into contact with the stopper while the stopper is positioned at the operative position.

3. 3. The transport device according to claim 1, wherein the moving device moves the stopper from the operating position to the retracted position after a predetermined time has elapsed since the supply of current to the motor was stopped.

4. A conveying method for conveying an object by a conveying device including: a belt on which an object is placed on an upper surface; a motor for driving the belt; a stopper provided at a predetermined position on the belt and restricting movement of the object in a conveying direction; and a moving device for moving the stopper to an operating position where the stopper can restrict movement of the object and to a retracted position where the stopper cannot restrict movement of the object, When the stopper is positioned at the operating position, if the transported object abuts against the stopper, When the weight of the conveyed object to be conveyed is such that slippage does not occur between the conveyed object and the belt when the motor is rotated and pulled by supplying current to the motor after the conveyed object has contacted the stopper, the supply of current to the motor is stopped to stop the rotation of the motor, a step of stopping the rotation of the motor while supplying current to the motor when the weight of the transported object to be transported is such that slippage occurs between the transported object and the belt when the motor rotates and the belt is pulled by supplying current to the motor after the transported object abuts against the stopper; and moving the stopper from the operating position to the retracted position after the rotation of the motor is stopped.

5. A circuit board processing machine including a conveying device that conveys a circuit board placed on an upper surface of a belt, and that performs a predetermined process on the circuit board conveyed to a predetermined position, The conveying device a motor that drives the belt; a stopper provided at the predetermined position on the belt to restrict movement of the circuit board in the conveying direction; a moving device that moves the stopper to an operating position where the stopper can restrict movement of the circuit board and to a retracted position where the stopper cannot restrict movement of the circuit board; a control device for controlling the driving of the motor; It is equipped with When the stopper is positioned at the operating position and the circuit board abuts against the stopper, the control device when the weight of the circuit board being transported is such that when the motor rotates and the belt is pulled by supplying current to the motor after the circuit board has contacted the stopper, the rotation of the motor is stopped by stopping the supply of current to the motor, If the weight of the circuit board being transported is such that slippage occurs between the circuit board and the belt when the motor rotates and the belt is pulled by supplying current to the motor after the circuit board has contacted the stopper, the rotation of the motor is stopped while current is being supplied to the motor, the moving device moves the stopper from the operating position to the retracted position after the rotation of the motor is stopped. Circuit board work machine.

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