Working device, working system and working method

Abstract

To provide a working device, a working system, and a working method capable of improving productivity by preventing occurrence of time loss when resuming an interrupted work.SOLUTION: After a work by a mounting work unit is interrupted and before the work is resumed, it is determined whether a board is located at a working position, based on whether a detection result by a plurality of optical sensors 18 has changed before and after the work is interrupted (step ST13). As a result, when it is determined that the board is not located at the working position, a transfer unit is caused to perform a re-locating operation for locating the board at the working position (step ST14), and then the mounting work unit is caused to restart the work (step ST14, step ST17), but when it is determined that the board is located at the working position, the mounting work unit is caused to restart the work without causing the transfer unit to perform the re-locating operation (step ST17).SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a work device, a work system, and a work method for performing a work on a workpiece positioned at a work position. [Background technology]

[0002] Conventionally, there is known a working device that transports a workpiece using a transport unit such as a belt conveyor, positions the workpiece at a working position, and performs a required operation on the workpiece positioned at the working position. An example of such a working device is a component mounting device that transports and positions a circuit board as a workpiece, and mounts components on the circuit board. In such a working device, the workpiece is positioned at the working position by starting the transport of the workpiece by the transport unit, and then stopping the operation of the transport unit when the workpiece reaches the working position (for example, see Patent Document 1 below).

[0003] However, in the above-mentioned working device, the work may be interrupted for some reason during the work. If the worker picks up the work during the interruption, the work may be displaced from its original position (working position), and the worker may not be able to work on the work accurately after the work is resumed. For this reason, in the past, when the work was interrupted in the working device, the transport unit was made to perform a repositioning operation to reposition the work to the working position before the work was resumed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6617068 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the transport unit had to perform a repositioning operation every time an interrupted operation was resumed, there would be a loss of work time if the workpiece had not been moved from its work position, resulting in a corresponding decrease in the productivity of the work device.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a work device, a work system, and a work method that can improve productivity by preventing time loss when resuming an interrupted work. [Means for solving the problem]

[0007] The working device of the present invention comprises a transporting unit which transports a workpiece and positions it at a working position, a working unit which performs work on the workpiece positioned at the working position by the transporting unit, a work detection means which detects the workpiece positioned by the transporting unit, and a judgment unit which judges whether the workpiece is positioned at the working position based on the detection result by the work detection means after work by the working unit is interrupted and before the work is resumed.

[0008] The work system of the present invention comprises a transporting unit which transports a work and positions it at a work position, a working unit which performs work on the work positioned at the work position by the transporting unit, a work detection means which detects the work positioned by the transporting unit, a judgment unit which judges whether the work is located at the work position based on the detection result by the work detection means after work by the working unit is interrupted and before the work is resumed, and an operation control unit which controls the operation of the transporting unit and the working unit, and when the judgment unit determines that the work is not located at the work position, the operation control unit causes the transporting unit to perform a repositioning operation to reposition the work at the work position and then resumes the work, and when the judgment unit determines that the work is located at the work position, the operation control unit causes the working unit to resume work without causing the transporting unit to perform the repositioning operation.

[0009] The working method of the present invention is a working method using a working device equipped with a transporting unit that transports a workpiece and positions it at a working position, a working unit that performs work on the workpiece positioned at the working position by the transporting unit, and a work detection means that detects the workpiece positioned by the transporting unit, and includes a judgment step of judging whether the workpiece is located at the working position based on the detection result by the work detection means after work by the working unit is interrupted and before the work is resumed, and a work resumption step of, if it is judged in the judgment step that the workpiece is not located at the working position, having the transporting unit perform a repositioning operation to reposition the workpiece at the working position and then having the working unit resume work, and if it is judged in the judgment step that the workpiece is located at the working position, having the working unit resume work without having the transporting unit perform the repositioning operation. Effect of the Invention

[0010] According to the present invention, it is possible to prevent time loss when resuming an interrupted work, thereby improving productivity. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic configuration diagram of a working system according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a perspective view of a main part of a component mounting device constituting a working system according to an embodiment of the present invention; [Diagram 3] FIG. 1 is a plan view of a main part of a component mounting device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a block diagram showing a control system of a component mounting device according to an embodiment of the present invention. [Diagram 5] 1A, 1B, and 1C are plan views illustrating a substrate transport operation by a transport unit included in a component mounting device according to an embodiment of the present invention. [Figure 6] 1A, 1B, and 1C are plan views showing examples of positions of a board when a component mounting device according to an embodiment of the present invention resumes an interrupted operation. [Figure 7]FIG. 13 is a diagram showing an example of a determination criterion table used by a determination unit included in the component mounting device according to the embodiment of the present invention. [Figure 8] A flowchart showing the procedure for performing a component mounting operation by a component mounting device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows an operating system 1 in one embodiment of the present invention. Operating system 1 includes a solder printer 1A, a component mounting device 1B, an inspection device 1C, and a host computer 1D. Solder printer 1A is a device that prints solder on a board KB, and component mounting device 1B is a device that mounts components BH on the board KB received from solder printer 1A. Inspection device 1C is a device that inspects components BH on board KB received from component mounting device 1B, and host computer 1D is a device that controls all of the devices that make up operating system 1.

[0013] Component mounting device 1B in working system 1 is an example of a working device in this embodiment. As shown in Figures 2 and 3, component mounting device 1B is equipped with base 11, conveying section 12, part feeder 13, mounting work section 14, board camera 15, and component camera 16. Conveying section 12, part feeder 13, and mounting work section 14 are controlled to operate by control device 17 (Figures 2 and 4) provided in base 11, and board camera 15 and component camera 16 are each controlled by control device 17 to perform imaging operations.

[0014] 2 and 3, the conveying section 12 includes a pair of belt conveyors 12a. The pair of belt conveyors 12a are arranged to extend horizontally on the base 11, and carry in the board KB sent from the upstream side (arrow A1 shown in FIG. 5(a)), and position the board KB at a predetermined work position set on the conveying path (FIG. 5(b)). The board KB positioned at the work position is loaded with components BH as described below. After the loading work of the components BH is completed, the conveying section 12 carries out the board KB to the downstream side (arrow A2 shown in FIG. 5(c)). Hereinafter, for the sake of convenience of explanation, the conveying direction of the board KB by the conveying section 12 (the left-right direction as seen from the worker OP in FIG. 2 and FIG. 3) is defined as the X direction, and the up-down direction is defined as the Z direction. In addition, the direction perpendicular to both the X direction and the Z direction (the front-back direction as seen from the worker OP) is defined as the Y direction.

[0015] 3 and 5(a), the conveying section 12 is provided with a plurality of optical sensors 18 (a leading section detection sensor 18a and a trailing section detection sensor 18b). Each optical sensor 18 includes a projector 18T that projects an inspection light LT, and a receiver 18J that receives the inspection light LT projected by the projector 18T. The projector 18T is provided at a position where the projected inspection light LT crosses above the two belt conveyors 12a that constitute the conveying section 12 in the Y direction. The receiver 18J is provided at a position facing the projector 18T in the Y direction.

[0016] The optical receiver 18J is turned off when it receives the inspection light LT, and is turned on when it does not receive the inspection light LT. The on / off state of the optical receiver 18J is notified to the control device 17. Therefore, based on the on / off state of the optical receiver 18J, the control device 17 can detect whether the board KB is positioned to block the inspection light LT.

[0017] 5(a), (b), and (c), the leading portion detection sensor 18a is provided at a position to detect the leading portion Ea of the substrate KB transported by the transport unit 12 when the substrate KB reaches the working position. That is, the leading portion detection sensor 18a is provided at a position where the inspection light LT is blocked by the leading portion Ea of the substrate KB (the leading portion detection sensor 18a is switched from off to on) when the substrate KB transported by the transport unit 12 reaches the working position.

[0018] 5(a), (b), and (c), the tail detection sensor 18b is provided at a position where the inspection light LT is blocked slightly forward (downstream) of the tail Eb of the substrate KB when it is positioned at the work position. In other words, the tail detection sensor 18b is provided at a position where it can detect the tail Eb of the substrate KB when it is positioned at the work position and moves slightly downstream. When the substrate KB is positioned at the work position, the tail detection sensor 18b is off before the inspection light LT is crossed by the leading edge Ea of the substrate KB (FIG. 5(a)), but it turns on after the inspection light LT is crossed by the leading edge Ea of the substrate KB, and maintains the on state even when the substrate KB reaches the work position and is stopped at that position (FIG. 5(b)).

[0019] As shown in Figures 2 and 3, a feeder base 11F is provided on the base 11, and the part feeder 13 is attached to the feeder base 11F. A plurality of part feeders 13 can be attached to the feeder base 11F and arranged in the X direction (Figures 2 and 3). The part feeder 13 has a part supply port 13K at the end closer to the conveying section 12, and continuously supplies parts BH to the part supply port 13K.

[0020] 2 and 3, the mounting work unit 14 includes a head moving mechanism 21 installed on a base 11, and a mounting head 22 that is moved by the head moving mechanism 21. The head moving mechanism 21 is composed of a fixed beam 21A fixed to the base 11 and extending in the Y direction, and a movable beam 21B having one end supported by the fixed beam 21A and extending in the X direction.

[0021] 2 and 3, the mounting head 22 is attached to a movable beam 21B. The movable beam 21B is movable in the direction in which the fixed beam 21A extends (Y direction), and the mounting head 22 is movable in the direction in which the movable beam 21B extends (X direction). Therefore, the mounting head 22 can move in the area above the base 11 within a horizontal plane (within the XY plane).

[0022] 2, the mounting head 22 is equipped with a plurality of nozzles 22N extending downward. The mounting head 22 can raise and lower the nozzles 22N by a built-in nozzle driving mechanism (not shown), and can also rotate the nozzles 22N about a vertical axis extending in the Z direction. The mounting head 22 can also generate a suction force at the lower end of the nozzle 22N by supplying a vacuum pressure into the nozzle 22N through a valve mechanism (not shown).

[0023] The mounting operation unit 14 mounts the component BH at each of a plurality of target mounting positions set on the board KB by repeatedly performing the operation (mounting turn) of mounting the component BH on the board KB that has been positioned at the operation position by the transport unit 12. One mounting turn consists of a pick-up operation, a moving operation, and a mounting operation. The pick-up operation is an operation in which the mounting head 22 lowers the nozzle 22N from above the parts feeder 13 and picks up the component BH at the lower end of the nozzle 22N, thereby removing the component BH from the parts feeder 13. The moving operation is an operation in which, after the pick-up operation, the mounting head 22 is driven by the head moving mechanism 21 to move to above the board KB. The mounting operation is an operation in which the mounting head 22, having moved to above the board KB, lowers the nozzle 22N and releases the suction of the component BH, thereby mounting the component BH at the target mounting position.

[0024] The board camera 15 is attached to the mounting head 22 and moves integrally with the mounting head 22. The imaging field of the board camera 15 faces downward, and images from above the two board marks MK provided on the board KB positioned at the work position. The board camera 15 images the board marks MK to obtain image data of the board marks MK, and then transmits the image data to the control device 17.

[0025] 2 and 3, the component camera 16 is provided in an area between the transport unit 12 and the feeder base 11F on the base 11. When the mounting head 22 moves from an area above the part feeder 13 to an area above the board KB during the movement operation of the mounting turn, the component camera 16 captures an image of the component BH from below. After capturing an image of the component BH to obtain image data of the component BH, the component camera 16 transmits the image data to the control device 17.

[0026] 4, control device 17 includes a memory unit 31, an operation control unit 32, and a judgment unit 33. Memory unit 31 stores a component mounting program that defines the procedure for performing the component mounting work, as well as various data (component data) such as the type and size of components BH to be mounted on board KB. Operation control unit 32 operates each unit of component mounting device 1B in accordance with the component mounting program stored in memory unit 31, and performs the component mounting work based on the component data.

[0027] When positioning the substrate KB at the working position by the transport unit 12, the operation control unit 32 controls the transport unit 12 based on the change in the on / off state of the leading portion detection sensor 18a. The leading portion detection sensor 18a is off before the substrate KB transported by the transport unit 12 reaches the working position (FIG. 5(a)), but turns on when the substrate KB reaches the working position (FIG. 5(b)). Therefore, after the transport unit 12 starts to carry in the substrate KB, the operation control unit 32 can position the substrate KB at the working position by stopping the operation of the transport unit 12 (transport operation of the substrate KB) when the leading portion detection sensor 18a switches from off to on.

[0028] The determination unit 33 determines whether the board KB (board KB before the work is resumed) is located at the work position when the work (loading turn) by the loading work unit 14 is interrupted for some reason and then the interrupted work is resumed. Specifically, it determines whether the board KB is located at the work position based on the detection results of the two optical sensors 18 (the front detection sensor 18a and the rear detection sensor 18b).

[0029] As mentioned above, the leading end detection sensor 18a is positioned to detect the leading end Ea of the substrate KB transported by the transport section 12 when the substrate KB reaches the working position, and the trailing end detection sensor 18b is positioned to detect the trailing end Eb of the substrate KB when the substrate KB located at the working position moves downstream. Therefore, after the substrate KB is positioned at the working position, as long as the substrate KB remains positioned at the working position, both the leading end detection sensor 18a and the trailing end detection sensor 18b remain on (Figure 6(a)).

[0030] In contrast, if the board KB is positioned at the working position and then moves upstream of the working position, the tail detection sensor 18b remains on, but the head detection sensor 18a switches from on to off (Figure 6(a) → Figure 6(b)). Also, if the board KB is positioned at the working position and then moves downstream of the working position, the head detection sensor 18a remains on, but the tail detection sensor 18b switches from on to off (Figure 6(a) → Figure 6(c)).

[0031] FIG. 7 shows a judgment criterion table 33T showing combinations of on / off of two optical sensors 18 (head detection sensor 18a and tail detection sensor 18b) and the positions of the board KB corresponding to the combinations. This judgment criterion table is stored in the control device 17 (FIG. 4), and when the work by the mounting work unit 14 is interrupted and then the interrupted work is resumed, the judgment unit 33 uses this judgment criterion table 33T to judge whether the board KB is located at the work position. Specifically, when the head detection sensor 18a and the tail detection sensor 18b are both on at the time of resuming the work, the judgment unit 33 judges that the board KB is located at the work position (FIG. 6(a)). Also, when the head detection sensor 18a is off and the tail detection sensor 18b is on, the judgment unit 33 judges that the board KB is shifted upstream from the work position (FIG. 6(b)). When the leading edge detection sensor 18a is on and the trailing edge detection sensor 18b is off, it is determined that the substrate KB has shifted downstream from the working position (FIG. 6(c)).

[0032] In this embodiment, the multiple (two) optical sensors 18 (the front detection sensor 18a and the rear detection sensor 18b) serve as work detection means for detecting the substrate KB as the work positioned by the conveying section 12.

[0033] Next, the procedure (operation method) of component mounting operation by component mounting device 1B will be described with reference to the flowchart shown in Fig. 8. When starting the component mounting operation, operation control section 32 first operates transport section 12 to receive and carry in board KB supplied from the upstream side (Fig. 5(a)). Then, when leading edge detection sensor 18a detects leading edge Ea of board KB, operation of transport section 12 is stopped to position board KB at the operation position (step ST1, board positioning process).

[0034] After positioning the board KB at the work position, the operation control unit 32 operates the mounting work unit 14 to perform a mounting turn (step ST2, work execution process). After each mounting turn, the operation control unit 32 determines whether the last component BH to be mounted on the board KB has been mounted on the board KB (step ST3). If the last component BH has not been mounted on the board, the operation control unit 32 returns to step ST2 and repeats the mounting turn.

[0035] In each mounting turn, image data of component BH captured by component camera 16 while mounting head 22 is moving is sent to controller 17, and controller 17 performs component recognition for that component BH. Information on the position and attitude of component BH relative to nozzle 22N obtained from this component recognition is used for correcting the position of nozzle 22N when component BH is mounted on board KB during the mounting operation of the mounting turn.

[0036] When the operation control unit 32 determines in step ST3 that the last component BH to be mounted on the board KB has been mounted on the board KB, it ends the mounting turn. Then, it operates the transport unit 12 to transport the board KB downstream (step ST4, board transport step). This completes the component mounting operation for one board KB.

[0037] As described above, when an operation input is made to interrupt the work (loading turn) by the loading work unit 14 while the work (loading turn) is being repeatedly performed, the operation control unit 32 interrupts the work by the loading work unit 14 (step ST11, work interruption process) and monitors whether an operation input (cancellation input) to cancel the interruption is made by the worker OP or the like (step ST12, cancellation input monitoring process). Then, when the operation control unit 32 detects that the cancellation input has been made, the judgment unit 33 judges whether the board KB is located at the work position based on the detection results by the two optical sensors 18 (the front detection sensor 18a and the rear detection sensor 18b). That is, the judgment unit 33 judges whether the board KB is located at the work position based on whether there has been a change in the detection results of the multiple (two) optical sensors 18 between the time the work is interrupted and the time the work is resumed (step ST13, judgment process).

[0038] In step ST13, specifically, the determination unit 33 checks whether one of the leading portion detection sensor 18a and the trailing portion detection sensor 18b, which were turned on when the board KB was positioned at the work position, is turned off. If there is a change in the detection result of the two optical sensors 18, that is, if one of the leading portion detection sensor 18a and the trailing portion detection sensor 18b is turned off (changed from on to off), the determination unit 33 determines that the board KB has moved upstream or downstream from the work position during the interruption of the work (i.e., the board KB is not positioned at the work position), and the operation control unit 32 causes the transport unit 12 to perform a repositioning operation to position (reposition) the board KB at the work position again (step ST14, repositioning process).

[0039] This repositioning operation is performed by first moving the substrate KB upstream and then downstream (FIG. 5(a)→FIG. 5(b)), and stopping the operation of the transport unit 12 when the leading edge detection sensor 18a switches from off to on. After the transport unit 12 performs the repositioning operation of the substrate KB in step ST14, the operation control unit 32 moves the substrate camera 15 above the substrate KB and checks whether the substrate KB is located at the work position (step ST16) by capturing an image of the two substrate marks MK on the substrate KB with the substrate camera 15 (step ST15). As a result, if the substrate KB is not located at the work position, the operation is terminated as an error due to some mechanical abnormality (step ST17), but if the substrate KB is located at the work position, the mounting operation unit 14 is caused to resume the operation (step ST18, work resumption process).

[0040] After causing mounting operation unit 14 to resume operation, if operation control unit 32 determines in step ST3 that the last component BH has been mounted on board KB, it ends the mounting turn and then operates transport unit 12 to remove board KB (step ST4).

[0041] On the other hand, in step ST13, if there is no change in the detection results of the two optical sensors 18, that is, if both the leading edge detection sensor 18a and the trailing edge detection sensor 18b are on (remain on), the judgment unit 33 judges that the board KB has not moved from the work position during the interruption of the work (i.e., the board KB is located at the work position), and the operation control unit 32 makes the board camera 15 take an image of the board mark MK without making the transport unit 12 perform a repositioning operation of the board KB (step ST15) and checks whether the board KB is located at the work position (step ST16). Then, if the board KB is not located at the work position, the operation control unit 32 ends the work with an error (step ST17), and if the board KB is located at the work position, the operation control unit 32 makes the mounting work unit 14 resume the work (step ST18, work resumption process). After making the mounting work unit 14 resume the work, if the operation control unit 32 judges that the last component BH has been mounted on the board KB (step ST3), it ends the mounting turn. Then, the transfer section 12 is operated to carry out the substrate KB (step ST4).

[0042] In this way, in the component mounting device 1B of the present embodiment, after the work by the mounting work unit 14 is interrupted and before the work is resumed, it is determined whether or not the board KB is located at the work position based on the detection results by the two optical sensors 18, which are the work detection means (more specifically, based on whether or not there is a change in the detection results of the two optical sensors 18 between the time the work is interrupted and the time the work is resumed) (step ST13). If it is determined that the board KB is not located at the work position, the transport unit 12 is made to perform a repositioning operation to reposition the board KB at the work position, and then the work is resumed (step ST13 → step ST14 → step ST15 → step ST16 → step ST18), and if it is determined that the board KB is located at the work position, the work is resumed without the transport unit 12 performing the repositioning operation (step ST13 → step ST15 → step ST16 → step ST18).

[0043] That is, in the component mounting device 1B (working system 1, working method) in this embodiment, before the interrupted work is resumed, it is checked whether the board KB is located at the work position, and as a result, if the board KB was not located at the work position before the work was resumed, the work is resumed after the repositioning operation of the board KB is performed as in the conventional method, but if the board KB was located at the work position before the work was resumed, the work is resumed without the repositioning operation of the board KB. Therefore, if the board KB has not moved from the work position during the interruption of the work, unnecessary repositioning of the board KB is not performed, and no time is lost.

[0044] As described above, in the component mounting device 1B (working system 1, working method) in this embodiment, before the interrupted work is resumed, it is checked whether the board KB is located at the work position, and if the result is that the board KB is not located at the work position, a repositioning operation is performed to position the board KB at the work position again, and the work is resumed, but if the board KB is located at the work position, the work is resumed without repositioning. Therefore, when the work is resumed, it is possible to eliminate the waste of repositioning the board KB even if the board KB has not moved from the work position during the interruption of the work, and it is possible to prevent time loss when resuming the interrupted work and improve the productivity of the component mounting device 1B.

[0045] Although the embodiment of the present invention has been described so far, the present invention is not limited to the above, and various modifications are possible. For example, in the above embodiment, the transport unit 12 that transports the board KB and positions it at the work position, the mounting work unit 14 as a work unit that performs work on the board KB positioned at the work position by the transport unit 12, the work detection means (multiple optical sensors 18) that detects the board KB positioned by the transport unit 12, the judgment unit 33 that judges whether the board KB is positioned at the work position based on the detection result by the work detection means after the work by the mounting work unit 14 is interrupted and before the work is resumed, and the operation control unit 32 that controls the operation of the transport unit 12 and the mounting work unit 14 are all configured to be provided in the component mounting device 1B, but these configurations may be provided anywhere in the entire work system 1. For example, the judgment unit 33 of the above configuration may be provided in the host computer 1D, etc.

[0046] In the above embodiment, the transport unit 12 that transports the board KB and positions it at the working position is comprised of the belt conveyor 12a, but this is just one example and the transport unit 12 does not have to be comprised of the belt conveyor 12a. In the above embodiment, the working device is the component mounting device 1B and the workpiece transported by the transport unit 12 is the board KB, but the working device does not have to be the component mounting device 1B and the workpiece does not have to be the board KB. [Industrial Applicability]

[0047] To provide a work device, a work system, and a work method capable of preventing time loss when resuming interrupted work and improving productivity. [Explanation of symbols]

[0048] 1. Work System 1B Parts mounting device (working device) 12 Conveyor section 14 Mounting work section (work section) 18 Optical sensor (workpiece detection means) 18a Head detection sensor 18b Rear detection sensor 32 Operation control section 33 Judgment Department KB Substrate (work) Ea beginning Eb posterior part

Claims

1. A transport unit that transports the workpiece and positions it at a work position; a working unit that performs an operation on the workpiece positioned at the work position by the transport unit; a work detection means for detecting the work positioned by the transport unit; a determination unit that determines whether or not the workpiece is located at the work position based on a detection result by the workpiece detection means after the work by the working unit is interrupted and before the work is resumed; A working device comprising:

2. 2. The working device according to claim 1, further comprising an operation control unit that controls the operation of the transport unit and the working unit, and when the judgment unit determines that the workpiece is not located at the working position, the operation control unit causes the transport unit to perform a repositioning operation to reposition the workpiece at the working position and then causes the working unit to resume work, and when the judgment unit determines that the workpiece is located at the working position, the operation control unit causes the working unit to resume work without causing the transport unit to perform the repositioning operation.

3. 3. The work device according to claim 1, wherein the work detection means includes a plurality of optical sensors, and the judgment unit judges whether the work is located at the work position based on whether there has been a change in the detection results of the plurality of optical sensors between the time when the work is interrupted and the time when the work is resumed.

4. A work device as described in claim 1 or 2, wherein the work detection means includes a plurality of optical sensors, and the judgment unit judges that the work is located at the work position if there is no change in the detection results of the plurality of optical sensors between the time when the work is interrupted and the time when the work is resumed, and judges that the work is not located at the work position if there is a change in the detection results of the plurality of optical sensors between the time when the work is interrupted and the time when the work is resumed.

5. The working device according to claim 3 or 4, wherein the plurality of optical sensors include a leading edge detection sensor that detects the leading edge of the work transported by the conveying unit when the work reaches the working position, and a trailing edge detection sensor that detects the trailing edge of the work when the work positioned at the working position moves downstream.

6. A transport unit that transports the workpiece and positions it at a work position; a working unit that performs an operation on the workpiece positioned at the work position by the transport unit; a work detection means for detecting the work positioned by the transport unit; a determination unit that determines whether or not the workpiece is located at the work position based on a detection result by the workpiece detection means after the work by the working unit is interrupted and before the work is resumed; An operation control unit that controls the operation of the transport unit and the working unit, The operation control unit includes: When the judgment unit determines that the workpiece is not located at the work position, the transport unit performs a repositioning operation to reposition the workpiece at the work position and then the work unit resumes work, and when the judgment unit determines that the workpiece is located at the work position, the work system causes the work unit to resume work without having the transport unit perform the repositioning operation.

7. A method for performing a work by a work device including a transport unit that transports a work and positions it at a work position, a work unit that performs a work on the work positioned at the work position by the transport unit, and a work detection means that detects the work positioned by the transport unit, comprising: a determination step of determining whether or not the workpiece is located at the work position based on a detection result by the workpiece detection means after the work by the working unit is interrupted and before the work is resumed; a work resumption step of, when it is determined in the determination step that the work is not located at the work position, having the transport unit perform a repositioning operation to reposition the work at the work position and then having the working unit resume work, and, when it is determined in the determination step that the work is located at the work position, having the working unit resume work without having the transport unit perform the repositioning operation; Including working methods.

Images