Screen printing device, method for controlling screen printing device, and program

Abstract

This screen printing device comprises: a squeegee that moves a coating material in a predetermined direction along a mask; a movement mechanism unit that moves the squeegee from a printing start position to a printing end position on the mask; a sensor that moves in the predetermined direction together with the squeegee and detects the coating material; and a control unit that controls the movement mechanism unit and determines the width of the coating material in the predetermined direction on the basis of the detection of the coating material by the sensor. After executing printing processing for moving the squeegee from the printing start position to the printing end position, the control unit executes detection processing for detecting an end section on the opposite side from the printing start position side in the coating material by moving the sensor in the predetermined direction and determines the width of the coating material in the predetermined direction on the basis of the detected position and the printing end position.

Description

Screen printing apparatus, method and program for controlling screen printing apparatus

[0001] The present invention relates to a screen printing apparatus that prints (applies) a coating material such as cream solder onto a substrate such as a printed circuit board.

[0002] A screen printing apparatus (hereinafter simply referred to as a printing apparatus) for printing a coating material such as cream solder onto a substrate such as a printed circuit board is known. The printing apparatus moves the coating material over a screen mask (hereinafter simply referred to as a mask) attached to the substrate using a squeegee. As the coating material moves, it is printed onto the substrate through openings (mask openings) formed in the mask.

[0003] In this type of printing device, a sensor detects the remaining amount of coating material on the mask after each set number of prints, and coating material is supplied (replenished) as needed. Specifically, as disclosed in Patent Document 1, a sensor that moves with the squeegee scans the top surface of the mask to measure the width of the solder (coating material). The remaining amount of solder is calculated based on this measured width, and solder is supplied if the remaining amount is insufficient.

[0004] However, the conventional printing device disclosed in Patent Document 1 requires sensors to actually detect the positions of both ends of the solder in the direction of squeegee movement, which takes time for measurement. Furthermore, the sensors may produce detection errors at both ends of the solder. Therefore, improvements are needed in these areas.

[0005] Patent Publication No. 2010-179628

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a screen printing device that can more quickly and accurately detect the width (remaining amount) of coating material on a screen mask.

[0007] A screen printing apparatus according to one aspect of the present invention comprises: a squeegee having a pressing surface for a coating material and moving the coating material in a predetermined direction along a screen mask via the pressing surface; a movement mechanism that moves the squeegee in the predetermined direction on the screen mask from a printing start position to a printing end position; a sensor that moves in the predetermined direction together with the squeegee and detects the coating material on the screen mask; and a control unit that controls the movement mechanism and determines the width of the coating material in the predetermined direction based on the detection of the coating material by the sensor, wherein the control unit performs a printing process that moves the squeegee from the printing start position to the printing end position, and then performs a detection process that moves the sensor in the predetermined direction to detect the end of the coating material on the opposite side from the printing start position, and determines the width of the coating material in the predetermined direction based on the detected position and the printing end position.

[0008] FIG. 1 is a schematic side view of a screen printing apparatus. FIG. 2 is a schematic front view (main parts) of the screen printing apparatus. FIG. 3 is an enlarged view of a printing unit in FIG. 1. FIG. 4 is a block diagram showing a control system of the screen printing apparatus. FIG. 5 is a flowchart showing operation control of the screen printing apparatus. FIG. 6 is a flowchart showing a subroutine process (roll width measurement process) of the operation control. FIG. 7 is an explanatory diagram of the squeegee direction change operation. FIG. 8A is an explanatory diagram (1) of the roll width measurement process. FIG. 8B is an explanatory diagram (2) of the roll width measurement process. FIG. 8C is an explanatory diagram (3) of the roll width measurement process. FIG. 8A is an explanatory diagram (4) of the roll width measurement process. FIG. 9B is an explanatory diagram (5) of the roll width measurement process. FIG. 9C is an explanatory diagram (6) of the roll width measurement process. FIG. 10A is an explanatory diagram (1) of the roll width measurement process according to a modified example. FIG. 10B is an explanatory diagram (2) of the roll width measurement process according to a modified example.

[0009] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0010] [Overall Configuration of Screen Printing Apparatus] Fig. 1 is a side view showing the schematic configuration of a screen printing apparatus 1 (hereinafter abbreviated as printing apparatus 1) according to a first embodiment of the present invention, and Fig. 2 is a front view of the printing apparatus 1 (viewed from the Y2 side). Note that in the figure, XYZ Cartesian coordinates are shown to clarify directional relationships. The X direction is the horizontal direction, the Z direction is the vertical direction (up and down direction), and the Y direction is a direction perpendicular to both the X and Z directions. Note that the X direction corresponds to the "predetermined direction" in the present invention. The Y1 direction corresponds to the "first direction" in the present invention, and the Y2 direction corresponds to the "second direction" in the present invention.

[0011] The printing apparatus 1 includes a printing work section 2A that performs printing processing on a substrate P such as a printed circuit board, and a mask storage section 2B that is disposed adjacent to the printing work section 2A on the Y1 side (one side in the Y direction / the right side in FIG. 1 ). The mask storage section 2B stores replacement screen masks.

[0012] The printing work section 2A is provided with a mask holding unit 3, a substrate holding unit 4, and a printing unit 5.

[0013] The substrate holding unit 4 includes an upper unit 4 A and a lower unit 4 B. The upper unit 4 A holds the substrate P during printing operations, and is equipped with a conveyor 20 for transporting the substrate P, a substrate support mechanism 22 that lifts and supports the substrate P from the conveyor 20, and a substrate clamping mechanism 24 that clamps the substrate P lifted from the conveyor 20.

[0014] The conveyor 20, substrate support mechanism 22, and substrate clamp mechanism 24 are operated by actuators such as motors or air cylinders (hereinafter, may be simply referred to as actuators). The substrate P is carried onto the conveyor 20 from the upstream side in the X direction (the rear side in the direction perpendicular to the plane of the paper in FIG. 1 / the X2 side in FIG. 2), and is held in a state where it is positioned in the upper unit 4A by the substrate support mechanism 22 and substrate clamp mechanism 24. After the printing process, the substrate P is released from the positioning state by the substrate support mechanism 22 and substrate clamp mechanism 24, and is carried out downstream in the X direction by the conveyor 20.

[0015] The lower unit 4B moves the substrate P positioned (held) by the upper unit 4A together with the upper unit 4A. Although details are omitted in Figure 1, the lower unit 4B is made up of a table and a table drive mechanism that displaces the table in the X, Y, Z, and R directions by driving an actuator. The R direction is the direction of rotation around an axis extending in the Z direction.

[0016] The upper unit 4A is fixed onto the table of the lower unit 4B. With this configuration, the substrate holding unit 4 is able to move the substrate P in each of the X, Y, Z and R directions.

[0017] The mask holding unit 3 is disposed above the substrate holding unit 4. The mask holding unit 3 holds a screen mask 6. The screen mask 6 is rectangular (rectangular or square) in plan view and is composed of a mask body 6a, which is a thin metal plate in which printing openings (mask openings) are formed, and a metal frame 6b that holds the peripheral edge of the mask body 6a. In the following description, the screen mask 6 will be abbreviated to mask 6, and unless otherwise specified, the term mask 6 refers to the mask body 6a.

[0018] The mask holding unit 3 includes a pair of guide members 26 extending parallel to each other in the Y direction and spaced apart in the X direction, and a mask clamping device (not shown) that clamps the mask 6 to the pair of guide members 26. The mask clamping device is actuated by an actuator.

[0019] Each guide member 26 is an L-shaped cross-section member made of a metal material such as stainless steel and includes a support portion 27a that supports the mask 6 and a guide portion 27b that restrains the mask 6 from the outside in the X direction. A mask clamp device is provided on each guide member 26 and includes a clamp plate and an actuator that drives the clamp plate forward and backward in the Z direction. The mask clamp device fixes the mask 6 to the guide member 26 by sandwiching a frame body 6b between the support portion 27a of the guide member 26 and the clamp plate.

[0020] The printing unit 5 is provided in the space above the mask holding unit 3 so as to be movable in the Y direction. The printing unit 5 mainly functions to move the solder paste along the upper surface of the mask 6. Solder paste (hereinafter referred to as solder) is an example of a coating material of the present invention, and is a semi-fluid that is conductive and viscous.

[0021] The printing unit 5 moves in the Y direction by operation of a Y-axis drive mechanism 10. The printing unit 5 includes a beam 5a extending in the X direction. The Y-axis drive mechanism 10 (corresponding to the "movement mechanism" of the present invention) is a screw feed mechanism including a pair of rails 12 extending in the Y direction and movably supporting both longitudinal ends of the beam 5a, a screw shaft 14 arranged parallel to the rails 12 and threadedly inserted into a nut member (not shown) of the beam 5a, and a motor 15 that drives the screw shaft 14. In other words, the motor 15 rotates the screw shaft 14, thereby moving the printing unit 5 in the Y direction along the rails 12. Note that the Y-axis drive mechanism 10 may be a mechanism other than a screw feed mechanism.

[0022] 1, the rails 12 and the screw shafts 14 extend from the Y2-side end of the printing work section 2A to the middle of the mask storage section 2B, thereby enabling the printing unit 5 to move in the Y direction from the Y2-side end of the printing work section 2A to the middle of the mask storage section 2B.

[0023] The printing unit 5 is equipped with a squeegee 16 , a squeegee drive mechanism 17 , a mask slider 18 , a solder supply unit 7 , and an X-axis drive mechanism 8 .

[0024] The squeegee 16 is a plate member that presses the solder supplied onto the mask 6 in the Y direction along the mask 6. The squeegee 16 is rectangular and elongated in the X direction, with a flat pressing surface 16a that presses the solder. The pressing surface 16a is made of a polymer material such as urethane rubber, polyacetal, polyethylene, or polyester, or a metal material such as stainless steel. The squeegee 16 moves back and forth in the Y direction together with the printing unit 5. The solder on the mask 6, i.e., as shown in FIG. 2, a mass of solder (referred to as a solder roll S) extending in the X direction on the mask 6, moves in the Y direction along the top surface of the mask 6 while being pressed by the squeegee 16 via the pressing surface 16a.

[0025] The squeegee drive mechanism 17 includes a rotation mechanism that rotates the squeegee 16 about an axis Ax extending in the X direction by operation of an actuator, and an elevation mechanism that raises and lowers the squeegee 16 relative to the beam 5a (moves it in the Z direction) by operation of an actuator. By operation of the squeegee drive mechanism 17, the squeegee 16 moves to a position where it can slide on the mask 6 (the position shown by the two-dot chain line in FIG. 1 ) and a position where it retracts above the mask 6 (the position shown by the solid line in FIG. 1 ).

[0026] During the printing process, the squeegee 16 is shifted in position by the operation of the squeegee drive mechanism 17 so that the pressing surface 16a faces forward in the direction of travel, and the angle of the pressing surface 16a is also changed. That is, the printing device 1 executes an outbound printing process in which printing is performed while the squeegee 16 is moved from the Y2 side toward the Y1 side, and a return printing process in which printing is performed while the squeegee 16 is moved from the Y1 side toward the Y2 side. As shown in FIG. 3 , the squeegee 16 is shifted in position so that the pressing surface 16a faces the Y1 side during the outbound printing process, and so that the pressing surface 16a faces the Y2 side during the return printing process. Note that FIG. 3 is an enlarged view of the printing unit in FIG. 1 .

[0027] The angle θ formed between the pressing surface 16a of the squeegee 16 and the upper surface of the mask body 6a is called the attack angle. The attack angle θ is set to an angle suitable for the printing process based on various conditions such as the type (properties) of solder, the opening area of ​​the mask 6, and the movement speed of the squeegee 16.

[0028] The mask slider 18 is a mask engagement device used to move the screen mask 6 between the printing work unit 2A and the mask storage unit 2B. The mask slider 18 includes a pin 18a extending in the Z direction and a pin drive unit 18b, such as an air cylinder, that drives the pin 18a forward and backward in the Z direction. The pin 18a is displaced by the pin drive unit 18b between a protruding position (lower position) where its tip (lower end) is lower than the top surface of the frame 6b and a retracted position (upper position) where it is retracted above the mask 6. That is, the mask slider 18 moves the mask 6 in the Y direction as the printing unit 5 moves by hooking the pin 18a onto the frame 6b of the mask 6. Note that FIGS. 1 and 3 show the mask slider 18 with the pin 18a displaced to the retracted position.

[0029] The mask storage section 2B is provided with a mask stocker 30 that stores a plurality of removably inserted masks 6, and an elevator mechanism (not shown) that raises and lowers (moves in the Z direction) the mask stocker 30. The mask stocker 30 has upper and lower storage sections 32a, 32b, and two types of masks 6 with different mask opening patterns are stored in these storage sections 32a, 32b.

[0030] The lifting mechanism is operated by the actuator and selectively positions either the first storage section 32a or the second storage section 32b at a predetermined mask replacement height position facing the guide member 26 in the X direction. Fig. 1 shows a state in which the lower storage section 32b is positioned at the mask replacement height position and the mask 6 stored in storage section 32b is positioned in the printing work section 2A (guide member 26).

[0031] The solder supply unit 7 is a device that supplies solder onto the mask 6. As shown in Figures 1 and 3, the solder supply unit 7 is disposed on the Y2 side of the beam 5a, and is movable in the Y direction relative to the beam 5a by an X-axis drive mechanism 8. The X-axis drive mechanism 8 is comprised of a screw feed mechanism or the like driven by a motor, and moves the solder supply unit 7 in the X direction as shown in Figure 2.

[0032] The solder supply unit 7 includes a unit frame 7a connected to the X-axis drive mechanism 8, and a supply head 40 fixed to the unit frame 7a.

[0033] The supply head 40 has a cylindrical solder container 42 that extends vertically and has a solder discharge portion 42a at its tip (lower end). The solder discharge portion 42a is a portion that discharges the solder contained in the solder container 42 toward the mask 6. For example, the solder discharge portion 42a is provided with a discharge port that opens and closes by operating a shutter member (not shown), and the amount of solder discharged (supplied) by the solder supply unit 7 is controlled according to the open time of the discharge port.

[0034] 1 and 3, a solder sensor 9 is disposed on the beam 5a of the printing unit 5. The solder sensor 9 is disposed on the Y1 side of the position of the squeegee 16, more specifically, at a predetermined position on the Y1 side of the movable range of the squeegee 16 in the Y direction.

[0035] The solder sensor 9 is used to measure the width of the solder roll S on the mask 6, specifically the width of the solder roll S in the Y direction. The solder sensor 9 is, for example, an optical reflective sensor (non-contact sensor) equipped with a light-emitting unit and a light-receiving unit. As the printing unit 5 moves in the Y direction, the solder sensor 9 scans the upper surface of the mask 6 (mask body 6a) while irradiating the upper surface of the mask 6 with light from the light-emitting unit. During scanning, the irradiated light is reflected by the mask 6 and enters the light-receiving unit at positions where the solder roll S is not present, whereas the irradiated light is scattered at positions where the solder roll S is present and does not enter the light-receiving unit. Thus, the solder sensor 9 can detect the presence or absence of the solder roll S on the mask 6 based on whether or not the irradiated light is received.

[0036] The solder sensor 9 outputs a signal according to the detection state of the solder roll S to the print control unit 101 described below. That is, the solder sensor 9 outputs an OFF signal when it detects the solder roll S, and outputs an ON signal when it does not detect the solder roll S. The print control unit 101 can determine the width of the solder roll S based on the input signal from the solder sensor 9.

[0037] [Configuration of Control System] Fig. 4 is a block diagram showing the control system of the printing device 1. The printing device 1 is equipped with a control device 100 that performs overall control of the operation of the printing device 1.

[0038] The control device 100 is composed of a processor such as a CPU, a ROM, a RAM, and peripheral devices, and includes a print control unit 101, a solder supply control unit 102, a storage unit 103, and the like as its functional components.

[0039] The printing control unit 101 (corresponding to the "control unit" of the present invention) controls the operation of each part, such as the mask holding unit 3, the substrate holding unit 4, the Y-axis drive mechanism 10, the squeegee drive mechanism 17, the solder sensor 9, and the mask slider 18, in accordance with the program, production plan information, and production substrate data stored in the memory unit 103 to perform the printing process and the roll width measurement process that measures the width of the solder roll S, and also performs various judgments and calculations required for the printing process and the roll width measurement process.

[0040] The solder supply control unit 102 controls the operations of the solder supply unit 7, the X-axis drive mechanism 8, and the Y-axis drive mechanism 10 in accordance with a program stored in the storage unit 103 to execute the solder supply process onto the mask 6 based on the width of the solder roll S determined in the roll width measurement process, and also executes various determinations and calculations required for the solder supply process. The program may be stored in a portable storage medium.

[0041] 5 is a flowchart showing the operation control of the printing device 1. When this flowchart starts, the print control unit 101 executes the printing process (steps S1 and S3).

[0042] Specifically, the print control unit 101 controls the substrate holding unit 4, and first loads the substrate P into the machine and has it held by the upper unit 4A, and then has the lower unit 4B place the substrate P on the underside of the mask 6. Next, the print control unit 101 controls the Y-axis drive mechanism 10 and the squeegee drive mechanism 17 to position the squeegee 16 at a print start position on the mask 6, and then moves the squeegee 16 from the print start position along the mask 6. With this movement, the solder roll S on the mask 6 is moved by the squeegee 16, and solder is applied (printed) onto the substrate P through the mask opening.

[0043] More specifically, in the forward printing process, the print control unit 101 moves the squeegee 16 from a print start position Ps1 (see FIG. 3 ), which is set near the Y2 end of the mask 6, to a print end position Pe1, which is set near the Y1 end of the mask 6. In the backward printing process, the print control unit 101 moves the squeegee 16 from a print start position Ps2, which is set near the Y1 end of the mask 6, to a print end position Pe2, which is set near the Y2 end of the mask 6. Note that the print start positions Ps1 and Ps2 and the print end positions Pe1 and Pe2 are determined by the contact position between the squeegee 16 and the mask 6.

[0044] When the squeegee 16 reaches the printing end position Pe1, Pe2, i.e., when the printing process is completed (Yes in step S3), the printing control unit 101 controls the substrate holding unit 4 to pull the substrate P downward away from the mask 6, and then transports the substrate P after the printing process out of the machine.

[0045] In addition, in parallel with the removal of the substrate P, the printing control unit 101 controls the squeegee drive mechanism 17 and the Y-axis drive mechanism 10 to switch from one of the forward printing process and the return printing process to the other, and performs a direction change operation to reverse the direction of the squeegee 16.

[0046] 7, the print control unit 101 rotates the squeegee 16 around the solder roll S and moves the squeegee 16 so that the pressing surface 16a contacts the solder roll S over the entire range from the start to the end of rotation of the squeegee 16, or over a portion of that range. Note that while Fig. 7 shows the movement of the squeegee 16 when switching from the forward pass printing process to the return pass printing process, the movement of the squeegee 16 when switching from the forward pass printing process to the return pass printing process is similar except for the direction of rotation.

[0047] In this case, the print control unit 101 acquires information about the movement trajectory of the squeegee 16 for contacting the solder roll S, specifically, the movement trajectory of the squeegee 16 that describes an upwardly convex elliptical arc, and can control the movement of the squeegee 16 based on this movement trajectory. The movement trajectory is information determined from the predicted width (width in the Y direction) of the solder roll S, the predicted height of the solder roll S, and design information for each part. The predicted value of the solder roll S can be calculated based on the amount of solder supplied onto the mask 6 at the start of the printing process (initial solder amount), the average consumption amount which is the average amount of solder consumed in one printing process, and the total number of times the printing process has been performed from the first time to the time of measurement.

[0048] When the printing process is completed, the printing control unit 101 further determines whether the printing process was an outbound printing process (step S5). If the determination here is Yes, the printing control unit 101 executes a roll width measurement process.

[0049] 6 is a flowchart showing the roll width measurement process (subroutine). As already mentioned, the roll width measurement process is a process for measuring the width of the solder roll S on the mask 6 in the X direction.

[0050] When the printing process ends with the squeegee 16 reaching the printing end position Pe1 (Yes in step S3), the printing control unit 101 determines whether the solder sensor 9 has detected the solder roll S at that time (step S21).

[0051] If the result of the processing in step S21 is Yes, the printing control unit 101 moves the printing unit 5 (squeegee 16) in the Y1 direction from the printing end position Pe1 and performs a detection process to detect the Y1 side end of the solder roll S (steps S23, S25).

[0052] 8A to 8C are diagrams illustrating the specific operation of the printing unit 5 in steps S21 to S25. If the solder sensor 9 detects the solder roll S at the time the printing process is completed (FIG. 8A), the printing control unit 101 temporarily stops the operation of the squeegee 16 during the previously described direction change of the squeegee 16. Specifically, the printing control unit 101 stops the operation of the squeegee 16 when the pressing surface 16a is parallel to the upper surface of the mask 6 (FIG. 8B), and then moves the printing unit 5 in the Y1 direction (FIG. 8C). That is, the printing control unit 101 moves the printing unit 5 (solder sensor 9) in the X1 direction while maintaining the pressing surface 16a in contact with or in close proximity to the apex of the solder roll S.

[0053] When the printing unit 5 moves, the input signal from the solder sensor 9 changes from an OFF signal to an ON signal at position P0 of the Y1-side end of the solder roll S. Therefore, based on this change in input signal, the print control unit 101 can detect position P0 of the Y1-side end of the solder roll S, i.e., the end position opposite the print start position Ps1.

[0054] After detecting the Y1 side end of the solder roll S, the print control unit 101 moves the printing unit 5 to the Y2 side by the movement distance in step S23, and then resumes the direction change operation of the squeegee 16.

[0055] On the other hand, if the result of the processing in step S21 is No, the printing control unit 101 moves the printing unit 5 (squeegee 16) in the Y2 direction from the printing end position Pe1 and performs a detection process to detect the Y1 side end of the solder roll S (steps S27, S29).

[0056] 9A to 9C are diagrams illustrating the specific operation of the printing unit 5 in steps S21, S27, and S29. If the solder sensor 9 has not detected the solder roll S at the time the printing process is completed ( FIG. 9A ), the printing control unit 101 temporarily stops the operation of the squeegee 16 midway through its direction-changing motion, similar to the process in step S23. Specifically, the printing control unit 101 stops the operation of the squeegee 16 when the pressing surface 16 a is parallel to the top surface of the mask 6 ( FIG. 9B ), and then moves the printing unit 5 in the Y2 direction ( FIG. 9C ). That is, similar to the process in step S23, the printing control unit 101 moves the printing unit 5 (solder sensor 9) in the Y2 direction while maintaining the pressing surface 16 a in contact with or close to the apex of the solder roll S.

[0057] When the printing unit 5 moves, the input signal from the solder sensor 9 changes from an ON signal to an OFF signal at position P0 of the Y1-side end of the solder roll S. Therefore, based on this change in input signal, the print control unit 101 can detect position P0 of the X1-side end of the solder roll S (the end opposite the print start position Ps1).

[0058] After detecting the Y1 side end of the solder roll S, the print control unit 101 moves the printing unit 5 to the Y1 side by the movement distance in step S27, and then resumes the direction change operation of the squeegee 16.

[0059] When the position P0 of the Y1-side end of the solder roll S is detected by the processing of step S25 or step S29, the print control unit 101 calculates the width W of the solder roll S in the Y direction based on the detection result (position P0 of the solder roll S's end) and the print end position Pe1 (step S31). The print end position Pe1 can be considered to be equivalent to the position of the X2-side end of the solder roll S at the end of the return pass printing process. Therefore, the print control unit 101 can calculate the width W of the solder roll S from the print end position Pe1 and the end position P0 detected by the solder sensor 9 in steps S25 and S29.

[0060] In this example, the movement of the squeegee 16 in the Y direction, i.e., the operation of the Y-axis drive mechanism 10, is controlled based on the coordinates of the rotation center of the squeegee 16. Therefore, the print control unit 101 can obtain the print end position Pe1 based on control information such as the coordinates of the rotation center and the attack angle θ, as well as design information for each unit.

[0061] When the roll width measurement process is completed, the process returns to step S13 in Fig. 5. In step S13, the print control unit 101 determines whether or not production of the substrate P has been completed, that is, whether or not printing processing has been completed for a specified number of substrates P, such as one production lot. If the determination here is Yes, the print control unit 101 ends this flowchart, but if the determination here is No, the process returns to step S1.

[0062] If the determination in step S5 is No, i.e., if the printing process is determined to be a return pass printing process, the solder supply control unit 102 determines whether solder supply is necessary. Specifically, the solder supply control unit 102 determines whether the measured width of the solder roll S (the value calculated in step S31) is less than a set value (step S9). The set value is a value calculated based on, for example, the amount of solder supplied onto the mask 6 at the start of the printing process (initial solder amount), the average consumption amount which is the average value of solder consumed in one printing process, and the total number of printing processes from the first execution to the time of measurement.

[0063] If the determination in step S9 is Yes, the solder supply control unit 102 controls the X-axis drive mechanism 8, the Y-axis drive mechanism 10, and the solder supply unit 7 to execute the solder supply process (step S11).

[0064] For example, the solder supply control unit 102 supplies solder in an overlapping manner onto the solder roll S on the mask 6. In this case, in addition to supplying a preset amount of solder, the solder supply control unit 102 can calculate a supply amount based on the remaining amount of the solder roll S, i.e., the deviation between the measured width of the solder roll S and the set value, and supply that amount of solder.

[0065] If the result of the process in step S9 is No, that is, if the measured width of the solder roll S is determined to be equal to or greater than the set value, the solder supply control unit 102 skips the process in step S11 and proceeds to step S13.

[0066] [Effects] As described above, in the printing device 1 of the embodiment, after the forward printing process, i.e., after the printing process in which the squeegee 16 is moved from the printing start position Ps1 to the printing end position Pe1, the printing unit 5 (solder sensor 9) is moved in the Y direction to detect the position P0 of the end of the solder roll S on the Y1 side (the side opposite the printing start position Ps1). Then, the width W of the solder roll S in the X direction is determined based on this detected position P0 and the printing end position Pe1. In other words, the solder sensor 9 detects only one end of the solder roll S in the X direction.

[0067] Therefore, with the printing device 1 of the embodiment, it is possible to measure the width W of the solder roll S with a smaller movement of the printing unit 5 (solder sensor 9) compared to conventional devices that use a sensor to actually detect both ends of the solder roll S and measure the width of the solder roll S. Therefore, with the printing device 1 of the embodiment, it is possible to reduce the time required to measure the width of the solder roll S, and as a result, it is possible to improve the tact time of the printing device 1.

[0068] Furthermore, in the printer 1 of this embodiment, the width W of the solder roll S is determined based on the detection position P0 of the solder sensor 9 and the known position information of the printing end position Pe1. Therefore, compared to conventional devices that actually detect both ends of the solder roll with a sensor and therefore may contain detection errors at both ends, the measured width is less susceptible to the influence of errors. Therefore, with the printer 1 of this embodiment, it is possible to accurately measure the width of the solder roll S.

[0069] Therefore, according to the printing device 1 of the embodiment, it is possible to detect the width W of the solder roll S on the mask 6, i.e., the remaining amount of the solder roll S, more quickly and accurately.

[0070] Furthermore, in the printing device 1 of the embodiment, when the solder sensor 9 detects the end of the solder roll S, the printing unit 5 (solder sensor 9) is moved while maintaining the pressing surface 16a of the squeegee 16 in contact with the surface of the solder roll S. This prevents solder from scattering, which is likely to occur when the squeegee 16 is separated from the solder roll S. Therefore, according to the printing device 1 of the embodiment, when the solder sensor 9 detects the end of the solder roll S (the end on the Y1 side), it is less susceptible to the influence of scattered solder, and as a result, the solder sensor 9 can accurately detect the end of the roll S (the end on the Y1 side).

[0071] In this case, in the printing device 1 of this embodiment, the squeegee 16 is stopped in a position where the pressing surface 16a is parallel to the upper surface of the mask 6, and in this state the printing unit 5 (solder sensor 9) is moved in the Y direction. Therefore, with the printing device 1 of this embodiment, the solder roll S is not pressed in the Y direction by the squeegee 16, and in other words, the printing unit 5 (solder sensor 9) can be moved in the Y direction without affecting the position of the solder roll S on the mask 6.

[0072] Furthermore, in the printing device 1 of this embodiment, based on whether the solder sensor 9 detects the solder roll S when the squeegee 16 reaches the printing end position Pe1, if it does detect the solder roll S, the printing unit 5 (solder sensor 9) is moved in the Y1 direction (toward the opposite side of the printing end position Pe1) (step S23), and if it does not detect the solder roll S, the printing unit 5 is moved in the Y2 direction (step S27). Therefore, with the printing device 1 of this embodiment, the end of the solder roll S on the Y1 side (the side opposite the printing start position Ps1) can be robustly detected regardless of the remaining amount of solder roll S, i.e., the size of the width W of the solder roll S.

[0073] The printing device 1 described above is an example of a preferred embodiment of the screen printing device according to the present invention, and its specific configuration can be modified as appropriate without departing from the spirit of the present invention. For example, the following configurations can also be applied to the above-described printing device 1.

[0074] (1) In the printing apparatus 1 according to the embodiment, during the roll width measurement process (step S7 in FIG. 5 ), the squeegee 16 is stopped midway through its direction change, and the printing unit 5 (solder sensor 9) is moved in the Y direction ( FIGS. 8A to 8C , 9A to 9C ). However, during the roll width measurement process, the printing unit 5 may be moved in the Y direction prior to the direction change, separate from the direction change of the squeegee 16. For example, as shown in FIGS. 10A and 10B , after the squeegee 16 reaches the printing end position Pe1 and the printing process ends, the printing unit 5 may be moved toward the Y2 side while maintaining the squeegee 16's orientation. In this case, the squeegee 16 may be in contact with the mask 6 or may be spaced above the mask 6. This configuration is applicable when the solder sensor 9 is positioned forward (toward the Y1 side) of the squeegee 16 by a distance that prevents the solder sensor 9 from detecting the solder roll S when the squeegee 16 reaches the printing end position Pe1.

[0075] (2) In the printing device 1 of the embodiment, the solder sensor 9 is positioned away from the squeegee 16 in the Y1 direction, and therefore the roll width measurement process (step S7 in FIG. 5) is performed after the forward printing process. However, the solder sensor 9 may also be positioned away from the squeegee 16 in the Y2 direction. In this case, the roll width measurement process can be performed after the backward printing process. With this configuration, as with the printing device 1 of the embodiment, it is possible to more quickly and accurately detect the remaining amount of solder roll S on the mask 6.

[0076] (3) In the printing device 1 of the embodiment, when changing the direction of the squeegee 16, the squeegee 16 is rotated so that the pressing surface 16a comes into contact with the surface of the solder roll S (see FIG. 7). However, it may also be configured so that the pressing surface 16a is temporarily separated from the solder roll S, the squeegee 16 is rotated, and the direction of the squeegee 16 is changed by this rotation.

[0077] (4) The printing device 1 of the embodiment is configured to perform both the forward printing process and the return printing process by rotating the squeegee 16. However, the present invention is also applicable to a printing device that has a squeegee for the forward printing process that has a pressing surface facing the Y1 side and a squeegee for the return printing process that has a pressing surface facing the Y2 side, and that selectively uses these squeegees to perform the forward printing process and the return printing process.

[0078] The present invention described above can be summarized as follows.

[0079] According to one aspect of the present invention, a screen printing apparatus includes a squeegee having a pressing surface for pressing a coating material and moving the coating material along a screen mask in a predetermined direction via the pressing surface, a movement mechanism that moves the squeegee in the predetermined direction on the screen mask from a printing start position to a printing end position, a sensor that moves in the predetermined direction together with the squeegee and detects the coating material on the screen mask, and a control unit that controls the movement mechanism and determines a width of the coating material in the predetermined direction based on the detection of the coating material by the sensor. The control unit performs a printing process that moves the squeegee from the printing start position to the printing end position, and then performs a detection process that moves the sensor in the predetermined direction to detect an end of the coating material on the opposite side from the printing start position, and determines the width of the coating material in the predetermined direction based on the detected position and the printing end position.

[0080] With this configuration, after the printing process is completed, the sensor detects only the edge of the coating material on the screen mask opposite the printing start position. The width of the coating material is then calculated based on this detected position and the known printing end position. Therefore, when measuring the width of the coating material, the sensor movement distance is reduced compared to when the sensor actually detects both ends of the coating material in the predetermined direction. As a result, tact time can be improved.

[0081] Furthermore, as described above, the width of the coating material is determined based on the sensor detection position and the known printing end position, so there is less influence from detection errors compared to when the width of the coating material is determined by actually detecting both ends of the coating material with a sensor. This makes it possible to more accurately determine the width of the coating material, and ultimately to accurately determine the remaining amount of coating material on the screen mask.

[0082] Therefore, with the above configuration, it is possible to more quickly and accurately detect the remaining amount of coating material on the screen mask.

[0083] For example, in a configuration in which the sensor is positioned in front of the squeegee in the direction of movement of the squeegee during the printing process, in order to detect both ends of the coating material with the sensor, the sensor must be moved significantly in the opposite direction from the position at the end of the printing process to the printing end position.

[0084] Therefore, the above-mentioned configuration of the screen printing device, which can reduce the amount of movement of the sensor when measuring the width of the coating material, is particularly useful when the sensor is located in front of the squeegee in the direction of movement of the squeegee during the printing process.

[0085] The movement mechanism may also include a mechanism for changing the angle and height of the pressing surface of the squeegee, and the control unit may be configured to move the sensor in the specified direction during the detection process while maintaining the pressing surface of the squeegee in contact with the surface of the coating material by changing the angle and height of the pressing surface.

[0086] In this configuration, the sensor is moved in the specified direction while the squeegee is in contact with the surface of the coating material, causing the coating material to scatter, and thus making it possible for the sensor to detect the edge of the coating material without being affected by the scattered coating material.

[0087] In this case, the control unit may stop the squeegee in a position where the pressing surface is parallel to the upper surface of the mask screen, and in that state, move the sensor in the predetermined direction.

[0088] According to this configuration, the sensor is moved in the predetermined direction while the pressing surface of the squeegee is in contact with the apex of the coating material, so that the sensor can be moved in the predetermined direction without pressing the coating material in the predetermined direction with the squeegee, i.e., without affecting the position of the coating material on the screen mask.

[0089] The control unit may be configured to move the sensor to the opposite side of the printing end position if the sensor detects the coating material when the squeegee reaches the printing end position, and to move the sensor toward the printing end position if the sensor does not detect the coating material when the squeegee reaches the printing end position.

[0090] In this configuration, if the sensor detects the coating material at the end of the printing process, i.e., if the width of the coating material is relatively large (wide), the sensor is moved to the opposite side of the printing end position. On the other hand, if the sensor does not detect the coating material at the end of the printing process, i.e., if the width of the coating material is relatively small (narrow), the sensor is moved toward the printing end position. This makes it possible to robustly detect the end of the coating material on the opposite side of the printing start position, regardless of the width of the coating material.

[0091] In the above-mentioned screen printing device, when the direction from one side of the specified direction to the other side is defined as a first direction, and the direction opposite to the first direction is defined as a second direction, the movement mechanism includes a mechanism for changing the posture of the squeegee between a first posture in which the pressing surface faces the first direction and a second posture in which the pressing surface faces the second direction, the sensor is arranged to be positioned in front of the squeegee when the squeegee is in the second posture, and the control unit is configured to alternately perform, as the printing process, an outbound printing process in which the squeegee is moved in the first direction in the first posture, and a return printing process in which the squeegee is moved in the second direction in the second posture, and to perform the detection process after performing the outbound printing process and before performing the return printing process.

[0092] According to this configuration, it is possible to quickly and accurately detect the remaining amount of coating material after the forward printing process and before the backward printing process.

[0093] Furthermore, a control method for a screen printing apparatus according to one aspect of the present invention is a control method for a screen printing apparatus including: a squeegee having a pressing surface for a coating material and moving the coating material in a predetermined direction along a screen mask via the pressing surface; a movement mechanism unit that moves the squeegee in the predetermined direction on the screen mask from a printing start position to a printing end position; and a sensor that moves in the predetermined direction together with the squeegee and detects the coating material on the screen mask, the control method including the steps of: executing a printing process that moves the squeegee from the printing start position to the printing end position; executing a detection process that, after execution of the printing process, detects the end of the coating material on the opposite side to the printing start position by moving the sensor in the predetermined direction; and calculating the width of the coating material in the predetermined direction based on the detection position detected in the detection process and the printing end position.

[0094] In this control method, after the printing process is completed, a sensor detects only the edge of the coating material on the screen mask opposite the printing start position. The width of the coating material is then calculated based on the detected position and the known printing end position. Therefore, this control method reduces the amount of sensor movement when measuring the width of the coating material compared to when the sensor actually detects both ends of the coating material in the predetermined direction. As a result, tact time can be improved.

[0095] A program according to one aspect of the present invention causes a processor of a screen printing device that includes: a squeegee having a pressing surface for a coating material and that moves the coating material in a predetermined direction along a screen mask via the pressing surface; a movement mechanism that moves the squeegee in the predetermined direction on the screen mask from a printing start position to a printing end position; and a sensor that moves in the predetermined direction together with the squeegee and detects the coating material on the screen mask, to execute the above-mentioned control method for a screen printing device.

[0096] According to this program, it is possible to control the screen printing device based on the above-described control method, and as a result, it is possible to cause the screen printing device to execute the above-described printing process and the above-described measurement process, thereby determining the width of the coating material in the predetermined direction.

Claims

1. A screen printing device comprising: a squeegee having a pressing surface for pressing a coating material and moving the coating material in a predetermined direction along a screen mask via the pressing surface; a movement mechanism that moves the squeegee in the predetermined direction on the screen mask from a printing start position to a printing end position; a sensor that moves in the predetermined direction together with the squeegee and detects the coating material on the screen mask; and a control unit that controls the movement mechanism and determines the width of the coating material in the predetermined direction based on the detection of the coating material by the sensor, wherein the control unit performs a printing process that moves the squeegee from the printing start position to the printing end position, and then performs a detection process that moves the sensor in the predetermined direction to detect the end of the coating material on the opposite side to the printing start position, and determines the width of the coating material in the predetermined direction based on the detected position and the printing end position.

2. A screen printing apparatus according to claim 1, wherein the sensor is located in front of the squeegee in the direction of movement of the squeegee during the printing process.

3. A screen printing device as described in claim 2, wherein the movement mechanism includes a mechanism for changing the angle and height of the pressing surface of the squeegee, and the control unit, in the detection process, moves the sensor in the specified direction while maintaining the pressing surface of the squeegee in contact with the surface of the coating material by changing the angle and height of the pressing surface.

4. A screen printing device according to claim 3, wherein the control unit stops the squeegee in a position where the pressing surface is parallel to the upper surface of the mask screen, and in that state moves the sensor in the specified direction.

5. A screen printing device as described in claim 4, wherein the control unit moves the sensor to the opposite side of the printing end position if the sensor detects the coating material when the squeegee reaches the printing end position, and moves the sensor toward the printing end position if the sensor does not detect the coating material when the squeegee reaches the printing end position.

6. A screen printing device as defined in any one of claims 2 to 5, wherein, when the direction from one side of the predetermined direction to the other side is defined as a first direction and the direction opposite to the first direction is defined as a second direction, the movement mechanism includes a mechanism for changing the position of the squeegee between a first position in which the pressing surface faces the first direction and a second position in which the pressing surface faces the second direction, the sensor is provided so as to be positioned in front of the squeegee when the squeegee is in the second position, and the control unit alternately performs, as the printing process, an outbound printing process in which the squeegee is moved in the first direction in the first position and a return printing process in which the squeegee is moved in the second direction in the second position, and performs the detection process after the outbound printing process is performed and before the return printing process is performed.

7. A control method for a screen printing device comprising: a squeegee having a pressing surface for a coating material and moving the coating material in a predetermined direction along a screen mask via the pressing surface; a movement mechanism that moves the squeegee in the predetermined direction on the screen mask from a printing start position to a printing end position; and a sensor that moves in the predetermined direction together with the squeegee and detects the coating material on the screen mask, the control method comprising: a step of executing a printing process that moves the squeegee from the printing start position to the printing end position; a step of executing a detection process after executing the printing process that detects the end of the coating material on the opposite side to the printing start position by moving the sensor in the predetermined direction; and a step of calculating the width of the coating material in the predetermined direction based on the detection position detected in the detection process and the printing end position.

8. A program for causing a processor of a screen printing device to execute the method for controlling a screen printing device described in claim 7, the program comprising: a squeegee having a pressing surface for a coating material and moving the coating material in a predetermined direction along a screen mask via said pressing surface; a movement mechanism unit that moves said squeegee in said predetermined direction on said screen mask from a printing start position to a printing end position; and a sensor that moves in said predetermined direction together with said squeegee and detects said coating material on the screen mask.

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