screen printing machine

Abstract

A screen printing machine prints viscous liquid onto a plate using a mask on which a printing pattern with a through-hole is formed.The screen printing machine comprises: a plate holder configured to hold the plate; a mask holder configured to hold an end portion of the mask along an outer circumference of the mask at a position above the plate held by the plate holder; an air nozzle configured to expel air in the direction of a target point on an upper surface of the mask held at the position above the plate; and a displacement measurement device configured to measure a displacement from one or more measurement target points, which are points on the upper surface before and after the expulsion of air and which correspond to the target point, in an up-down direction as the air is expelled from the air nozzle in the direction of the target point.

Description

Technical field

[0001] One of the techniques disclosed in the present description relates to a screen printing machine. State of the art

[0002] A screen printing machine that fills a through-hole in a mask with a viscous liquid while the mask is held above a plate. If a gap forms between the mask and the plate during the filling of the through-hole with the viscous liquid, the liquid can enter the gap. A screen printing machine described in patent literature 1 pushes the shaft of an actuator from above the mask against the upper surface of the mask. This displaces the mask downwards towards the plate according to the size of the gap formed between the mask and the plate. The screen printing machine measures the distance between the mask and the plate based on the displacement of the actuator shaft (i.e., the mask). List of oppositions patent literature

[0003] Patent Literature 1: JPH04-100849U Summary of the invention: Technical problem

[0004] The screen printing machine described above presses the actuator shaft against the upper surface of the mask to measure the distance between the mask and the plate. This can damage the upper surface of the mask. The present description provides a technique that reduces damage to the upper surface of the mask during distance measurement compared to the prior art. Problem solving

[0005] The screen printing machine disclosed in the present description prints viscous liquid onto a plate using a mask on which a printing pattern with a through-hole is formed.The screen printing machine comprises a plate holder configured to hold the plate, a mask holder configured to hold an end portion of the mask along an outer circumference of the mask at a position above the plate held by the plate holder, an air nozzle configured to expel air in the direction of a target point on an upper surface of the mask held at the position above the plate, and a displacement magnitude measuring device configured to measure a displacement magnitude from one or more measurement target points, which are points on the upper surface before and after the expulsion of air and correspond to the target point, in an up-down direction as the air is expelled from the air nozzle in the direction of the target point.

[0006] In the described screen printing machine, the mask is moved by the air expelled from the air nozzle without directly touching the mask's upper surface. This makes it possible to measure the displacement of the target point on the mask's upper surface in the up-down direction without contact. The screen printing machine described above is thus able to reduce damage to the mask's upper surface when measuring the distance between the mask and the plate. Brief description of the drawings Fig. Figure 1 is a side view of a screen printing machine according to a first example. Fig. Figure 2 is an enlarged representation of a section of the dashed line II in the Fig. 1. Fig. Figure 3 is a top view of a mask arranged in the screen printing machine according to the first example. Fig. Figure 4 is a configuration diagram of a control device for the screen printing machine according to the first example. Fig. Figure 5 is a flowchart of a plate printing process performed by the control device according to the first example. Fig. Figure 6 shows a flowchart of a plate printing process, which is carried out by the control device according to a second example. Description of embodiments

[0007] The main features of an example described below are listed. The technical elements described below are each independent technical elements, describe technical benefits alone or in various combinations, and are not limited to the combinations disclosed in the claims as originally filed.

[0008] (Feature 1) In the screen printing machine described above, the one or more measurement target points can contain the target point.

[0009] When air is expelled from a nozzle toward the target point, the displacement in the up-down direction is likely to be greater at the target point than at a point around the target point. With such a configuration, it is easier to measure the displacement in the up-down direction compared to a configuration where the displacement of the point in the up-down direction around the target point is measured.

[0010] (Feature 2) The screen printing machine described above may further include a plate lifter configured to lift the plate holder when the viscous fluid is printed onto the plate, and a lift-amount determination section configured to determine the lift of the plate holder. In this case, the lift-amount determination section may be configured to determine the lift based on the displacement of one or more target points measured by the displacement-amount determination section.

[0011] With such a configuration, it is possible to move the plate close to a mask based on the displacement of one or more measurement target points. This allows the distance between the plate and the mask to be reduced when the viscous fluid is printed onto the plate.

[0012] (Feature 3) The screen printing machine described above may further include an output quantity determination section configured to determine the volume of air discharged from the air nozzle. In this case, the target point may include a first target point and a second target point that is distinct from the first. The output quantity determination section may be configured to determine the volume of air discharged with respect to the second target point as a second discharge volume that differs from the first discharge volume with respect to the first target point. The displacement magnitude measuring device may be configured to measure the displacement magnitude of a first measurement target point corresponding to the first target point in the up-down direction and to measure the displacement magnitude of a second measurement target point corresponding to the second target point in the up-down direction.

[0013] This configuration makes it possible to change the air output volume depending on the position of the target point. Therefore, it is possible to determine the appropriate air output volume for the target point's position.

[0014] (Feature 4) The screen printing machine described above may further include an opening area determination section configured to determine the opening area of ​​an air nozzle outlet. In this case, the target point may include a first target point and a second target point that differs from the first. The opening area determination section may be configured to determine the opening area of ​​the outlet with respect to the second target point as a second opening area that differs from the first opening area of ​​the outlet with respect to the first target point. The displacement magnitude measuring device may be configured to measure the displacement magnitude of a first measurement target point corresponding to the first target point in the up-down direction and to measure the displacement magnitude of a second measurement target point corresponding to the second target point in the up-down direction.

[0015] This configuration makes it possible to change the opening area depending on the position of the target point. Therefore, it is possible to determine the appropriate opening area for the position of the target point.

[0016] (Feature 5) The screen printing machine described above may further include an operating control section configured to control operation of the plate holder, in which the plate holder may include a clamp configured to grip the end portion of the plate. In this case, the operating control section may be configured to cause the clamp to release the end portion of the plate and subsequently to cause the clamp to re-grip the end portion of the plate when the displacement of the target point, as measured by the displacement measurement device, exceeds a predetermined threshold.

[0017] If the clamp grips the end of the plate, the plate can bend. In this case, the distance between the mask and the plate is likely to be large. This increases the displacement of the measurement target point in the up-down direction. In such a configuration, the clamp is designed to open the end of the plate and grip it again if the displacement exceeds a predefined threshold. This prevents the plate from bending.

[0018] (Feature 6) The screen printing machine described above may further include a squeegee configured to fill the mask's through-hole with the viscous liquid, and a squeegee operation determination section configured to determine the pressure with which the squeegee is pressed against the mask's top surface and the speed at which the squeegee is moved along the mask's top surface. In this case, the squeegee operation determination section may be configured to determine at least one of the force and speed based on the displacement of the target point measured by the displacement measurement device.

[0019] With such a configuration, the operation (i.e., at least one of force and speed) of the squeegee is determined based on the amount of displacement. Thus, the screen printing machine can perform a pressure suitable for the distance between the mask and the plate. (First example)

[0020] With reference to the Fig. Figures 1 to 3 describe a configuration of the screen printing machine 10 (hereinafter referred to as the printing machine 10) according to a first example. The printing machine 10 is a device that prints solder paste 38, which is a viscous liquid, onto the printed circuit board 2 (hereinafter referred to as the board 2) using a mask 20. The board 2 is the object on which the printing is performed, and the printing machine conveys the board 2 to an electronic component assembly device, which is a further processing step. In the following drawings, the -Y direction is referred to as the front side. A +Y direction is referred to as a back side, a +Z direction as a top side, and a -Z direction as a bottom side.

[0021] The Fig. Figure 1 is a side view of the printing press 10. The printing press 10 comprises a doctor blade unit 30, a unit drive device 12, a mask holding device 24, a plate holding device 14, a gap measuring unit 40, a control device 50, a high-pressure reservoir 4, and an adjusting valve 6 in a box-shaped housing. Fig. Figure 1 shows the housing of the printing machine 10 in a transparent way; however, it actually consists of six plate materials and divides the interior of the printing machine 10.

[0022] The doctor blade unit 30 comprises the doctor blade 36, the angle adjustment device 34, and the lifting and lowering device 32. The doctor blade 36 is a flat, plate-shaped element with a rectangular form extending in an X-direction. In this example, the doctor blade 36 is a metal doctor blade, but in a modification, it could also be, for example, a urethane doctor blade. The angle adjustment device 34 sets the position of the doctor blade 36 relative to the plate 2 (an angle formed by the upper surface of the plate 2 and the doctor blade 36). The lifting and lowering device 32 moves the doctor blade 36 in the up-down direction. The lifting and lowering device 32 raises and lowers the doctor blade 36 relative to the plate 2 in the up-down direction to adjust the pressure with which the doctor blade 36 is pressed against the mask 20 (hereinafter referred to as the pressure force).

[0023] The plate holding device 14 comprises a pair of clamps 16F and 16S. This pair of clamps 16F and 16S grips the plate 2 from the front and rear, thus fixing the plate 2 to the plate holding device 14. The plate lifting device 15 and the plate conveying device 16 are located below the plate holding device 14. The plate lifting device 15 has a servo motor (not shown). The plate lifting device 15 operates the servo motor to raise and lower the plate holding device 14. Similarly, the plate conveying device 17 has a servo motor (not shown) and operates the servo motor to convey the plate 2 to the plate holding device 14 before printing and to move the printed plate 2 from the plate holding device 14 in a +X direction (i.e., in a direction shown in the drawing). Fig. 1 (closer to the viewer) to promote.

[0024] The drive device 12 moves the doctor blade unit 30 along a pair of guide rails in a front-to-back direction of the printing press 10 (i.e., in the drawing of the Fig. 1 a left-right direction). A detailed setup in which the drive device 12 moves the doctor blade unit 30 in the front-back direction is known and is therefore not described in detail here.

[0025] As in the Fig. As shown in Figure 3, the mask holding device 24 comprises a frame body located along the outer circumference of the mask 20. This frame body of the mask holding device 24 holds the end parts of the mask 20. This makes it possible to reduce the displacement of the mask 20 when the through-hole 22 of the mask 20 is filled with solder paste 38 by the doctor blade unit 30. The mask holding device 24 is provided with several holding mechanisms 26. The mask holding device 24, which holds the end parts of the mask 20, is held in a position above the plate 2 by several holding mechanisms 26.

[0026] The mask 20 has several through-holes 22. These through-holes 22 are arranged according to the print pattern 21. When the solder paste 38 is pressed against the upper surface of the mask 20 by the squeegee unit 36, the solder paste 38 passes through the through-holes 22 (i.e., the print pattern 21) and adheres to the plate 2. This prints the solder paste 38 onto the upper surface of the plate 2 according to the print pattern 21.

[0027] The distance measuring unit 40 is a unit for measuring a distance (gap) between the mask 20 and the upper surface of the plate 2 when the solder paste 38 is printed onto the plate 2. The distance measuring unit 40 comprises an air nozzle 44 (hereinafter referred to as nozzle 44), a displacement sensor 46, a lifting and lowering device 42, and a drive device 48. The nozzle 44 is connected to the high-pressure reservoir 4 via the adjusting valve 6. Compressed air is stored in the high-pressure reservoir 4. When the adjusting valve 6 is opened, the air from the high-pressure reservoir 4 is expelled from the nozzle 44 towards the mask 20. The amount of air expelled from the nozzle 44 towards the mask 20 varies depending on the degree of opening of the adjusting valve 6.

[0028] The displacement sensor 46 is a so-called optical sensor. It comprises a light projection section and a light reception section. The displacement sensor 46 emits laser light from the projection section towards an object to be measured. The incident light is reflected by the object, and the reflected light reaches the light reception section. The displacement sensor 46 detects the displacement of a non-measured object based on changes in the position of the light striking the light reception section. In a modified version, the displacement sensor 46 can, for example, be an ultrasonic sensor.

[0029] The lifting and lowering device 42 moves the nozzle 44 and the displacement sensor 46 in the up-down direction. The drive device 48 moves the nozzle 44 and the displacement sensor 46 in an X-direction. The gap measuring unit 40 is movable by the drive device 12 in the front-back direction (Y-direction) of the printing press 10. That is, the gap measuring unit 40 can move the nozzle 44 and the displacement sensor 46 along the upper surface of the mask 20.

[0030] The nozzle 44 and the displacement sensor 46 of the gap measuring unit 40 are described with reference to the Fig. 2 described. The nozzle 44 has a cylindrical shape extending in the up-down direction. At the lower end of the nozzle 44 are the opening 47 and the opening adjustment section 45. The opening adjustment section 45 is a mechanism for changing the area of ​​the opening 47 and comprises a wall that delimits the opening 47 of the nozzle 44. By moving the wall of the opening adjustment section 45 towards the center of the nozzle 44, the area of ​​the opening 47 of the nozzle 44 decreases. By moving the wall of the opening adjustment section 45 away from the center of the nozzle 44, the area of ​​the opening 47 increases.

[0031] As described above, the mask 20 is held by the mask holding device 24 in a position above the plate 2. Furthermore, the plate 2 is located below the mask 20 in a state where its end parts are held by the clamping pair 16F and 16S of the plate holding device 14. Since the mask 20 has a thin foil form of, for example, 1 mm or less, it can be partially displaced in the up-down direction. Since the plate 2 also has a relatively thin, flat plate form, it can deform when the end parts of the plate 2 are gripped by the clamps 16F and 16S, for example, so that a central part points upwards. Consequently, as shown in the Fig. Figure 2 shows a gap with a length C1 that varies depending on the position between the lower surface 20D of the mask 20 and the upper surface 2U of the plate 2.

[0032] If a large gap forms between the lower surface 20D of the mask 20 and the upper surface 2U of the plate 2, solder paste 38 will penetrate the gap when the through-hole 22 is filled with solder paste 38. This can cause a printing defect in which solder paste 38 is printed in an unintended location on the plate 2.

[0033] The gap measuring unit 40 measures the distance between the lower surface 20D of the mask 20 and the upper surface 2U of the plate 2 before the printing machine 10 performs the printing, i.e., before the squeegee 36 moves backward. Specifically, the gap measuring unit 40 expels air 60 through the nozzle 44 toward the target point PB on the upper surface 20U of the mask 20. If a gap exists between the lower surface 20D of the mask 20 and the upper surface 2U of the plate 2, the mask 20 moves downward by the length C1 of the gap, and the lower surface 20D of the mask 20 comes into contact with the upper surface 2U of the plate 2. The displacement of the mask 20 thus corresponds to the length C1 of the gap. The displacement sensor 46 measures the displacement between the target point PB before the air 60 is expelled and the target point PA after the air 60 has been expelled. Thus, the gap measuring unit 40 can measure the length C1 of the gap.The gap measuring unit 40 transmits the measured length C1 of the gap to the control device 50.

[0034] As in the Fig. As shown in Figure 3, the gap measuring unit 40 in this example measures the length of the gap at target points P1 to P9. Target points P1, P3, P6, and P8 are located at four corners of the mask 20. Target point P4 is located in the center of the mask 20. Target points P2, P5, P7, and P9 are located at the midpoints of the sides of the mask 20.

[0035] The configuration of the control device 50 is determined with reference to the Fig. 4 described. The control device 50 is configured with a computer with memory 51 and CPU 54. The control device 50 is communicatively connected to the devices 6 to 45 of the printing press 10.

[0036] Memory 51 contains a storage medium, such as a hard drive. Memory 51 stores the print program 52. The print program 52 is a program for printing solder paste 38 onto the plate 2 using the mask 20. The print program 52 contains the target point table T1, the displacement magnitude thresholds Dth1 and Dth2, and the print setting 53.

[0037] The target point table T1 stores the coordinates of each of the target points P1 to P9, the output quantity, and the opening area in relation to each other. Target point table T1 is a table for determining the output quantity of air 60 at each of the target points P1 to P9 and the opening area of ​​the nozzle 44. Target point table T1 is pre-stored in the printing program 52; however, an operator can modify, add to, or delete the target point coordinates based on the actual printing result. Furthermore, the operator can change the output quantity and the opening area.

[0038] In the target point table T1 of the present example, the output quantity V1 is set for target points P1 to P3 and P6 to P8. The output quantity V2 is set at target points P4, P5, and P9. As in the Fig. As shown in Figure 3, the target points P4, P5 and P9 lie in the center of plate 2 in the front-to-back direction (i.e. in the Fig. 3 a left-right direction). Since the end parts of plate 2 are gripped in the front-back direction by the clamp pair 16F and 16S as described above, the middle part is likely to shift upwards in the front-back direction. Therefore, at target points P4, P5, and P9, the distance between the upper surface 2U of plate 2 and the lower surface 20D of mask 20 (i.e., the length C1 of the gap) is likely to be short. At target points P1 to P3 and P6 to P8, the length C1 of the gap is likely to be large compared to target points P4, P5, and P9. Therefore, the ejection quantity V1 is set to be large compared to the ejection quantity V2.This makes it possible to move the mask 20 sufficiently until the lower surface 20D of the mask 20 comes into contact with the upper surface 2U of the plate 2, by ensuring that the air 60 has a discharge volume V1 that is greater than the discharge volume V2 at the end regions of the plate 2 in the front-to-back direction, where the gap length C1 is long. This allows the displacement sensor 46 to precisely measure the gap length C1. That is, the printing machine 10 can precisely measure the gap C1 by changing the discharge volumes V1 and V2 according to the positions of the target points P1 to P9.

[0039] Similarly, in the target point table T1 of the present example, the opening area A1 is set for target points P1 to P3 and P6 to P8. Meanwhile, the opening area A2 is set for target points P4, P5, and P9. The opening area A1 is set larger than the opening area A2. This makes it possible to move the mask 20 sufficiently until the lower surface 20D of the mask 20 comes into contact with the upper surface 2U of the plate 2 via air 60, which is expelled through the opening area A1, which is larger than the opening area A2 at the end regions of the plate 2 where the gap length C1 is long. This allows the distance between the upper surface 2U of the plate 2 and the lower surface 20D of the mask 20 to be measured precisely. This means that the printing press 10 can precisely measure the length C1 of the gap by further changing the opening areas A1 and A2 according to the positions of the target points P1 to P9.

[0040] The offset threshold Dth1 is a threshold for control device 50 to determine whether the clamp pair 16F and 16S needs to be reset in the sheet printing process described later. The offset threshold Dth2 is a threshold for control device 50 to determine whether the print setting 53 needs to be changed in the sheet printing process. Each of the thresholds Dth1 and Dth2 is pre-stored in print program 52 but can be changed by the operator.

[0041] The print setting 53 comprises the printing force F1 and the printing speed S1. These values ​​are pre-stored in the print program 52. The control device 50 is configured to adjust the printing force via the lifting and lowering device 32 of the doctor blade unit 30. The printing speed is the speed at which the doctor blade unit 30 moves backward, filling the through-holes 22 of the mask 20 with solder paste 38. The control device 50 is configured to adjust the printing speed via the unit drive device 12.

[0042] The CPU 54 executes various processes according to the printing program 52. Therefore, the CPU 54 functions as stroke-amount determination section 55, output quantity determination section 56, opening area determination section 57, operating control section 58, and squeegee operation determination section 59.

[0043] The plate printing process executed by the CPU 54 of the control device 50 of the printing press 10 is described with reference to the Fig. 5 described. After the mask 20 is held by the mask holder 24 and the plate 2 is held by the plate holder 14, the plate printing process is started in response to a print start instruction from the employee.

[0044] In step S10, the CPU 54 moves the nozzle 44 and the displacement sensor 46 in the sequence of target points P1 to P9 based on the target point table T1. Once the nozzle 44 and the displacement sensor 46 have moved to each of the target points P1 to P9, the CPU 54 causes the nozzle 44 to expel air 60 towards each of the target points P1 to P9. In this case, the CPU 54 changes the output quantity to output quantity V1 or V2 and the opening area to opening area A1 or A2 according to the target points P1 to P9 based on the target point table T1.

[0045] In step S12, the CPU 54 obtains the displacement amount of each of the target points P1 to P9 before and after the ejection of the air 60 from the displacement sensor 46.

[0046] In step S20, the CPU 54 compares the displacement amounts obtained from the displacement sensor 46 with the displacement amount threshold Dth1. If a displacement amount exceeding the displacement amount threshold Dth1 is not included in the displacement amounts (S20: NO), the CPU 54 proceeds to S22, and if a displacement amount exceeding the displacement amount threshold Dth1 is included in the displacement amounts (S20: YES), the CPU 54 proceeds to S24.

[0047] In S24, the CPU 54 resets the clamp pairs 16F and 16S. Specifically, the CPU 54 causes the clamp pair 16F and 16S to open the end sections of plate 2 in the front-to-back direction. Then, the CPU 54 causes the clamp pair 16F and 16S to re-engage the end sections of plate 2 in the front-to-back direction. This prevents deformation of plate 2 caused by the clamp pair 16F and 16S engaging. As a result, the length C1 of the gap described above can be reduced.

[0048] In step S22, the CPU 54 adjusts the height of the plate holder 14 according to the displacement of each of the target points P1 to P9 detected by the displacement sensor 46 in step S12. For example, the CPU 54 causes the plate lifter 15 to raise the plate holder 14 by the maximum displacement below the displacements obtained from the displacement sensor 46 in step S12. This allows the lower surface 20D of the mask 20 and the upper surface 2U of the plate 2 to make contact when the solder paste 38 is printed onto the plate 2. This reduces the occurrence of the printing defects described above. In a modification, the CPU 54 can raise the plate holder 14 by an average value of the displacements of the target points P1 to P9 obtained from the displacement sensor 46 in step S12.

[0049] In step S30, the CPU compares the displacement amount of each of the target points P1 to P9, as determined by displacement sensor 46, with the displacement threshold Dth2. If a displacement amount exceeding the displacement threshold Dth2 is not included in the displacement amounts (S30: NO), the CPU 54 skips S32 and proceeds to S40; if a displacement amount exceeding the displacement threshold Dth2 is included in the displacement amounts (S30: YES), the CPU 54 proceeds to S32.

[0050] In step S32, the CPU 54 modifies the pressure setting 53. Specifically, the CPU 54 increases the pressure force when passing the target point, which indicates a displacement exceeding the displacement threshold Dth2, compared to the initial pressure force F1, and decreases the printing speed compared to the initial printing speed S1. This allows the mask 20 to be pressed more firmly against the plate 2 by the squeegee 36 at the target point indicating the displacement exceeding the displacement threshold Dth2. This reduces the occurrence of printing defects. In one modification, the pressure setting 53 only needs to contain at least one pressure force F1 and one printing speed S1. In this case, the CPU 54 can modify at least one pressure force F1 and one printing speed S1 in step S32.

[0051] In step S40, the CPU 54 executes the printing process by moving the squeegee unit 30 backwards based on the print setting 53. This fills the through-hole 22 of the mask 20 with solder paste 38 and prints the solder paste 38 onto the plate 2.

[0052] With the printing machine 10 of the present example, it is possible to measure the displacements of the target points P1 to P9 in the up-down direction caused by the air 60 expelled from the nozzle 44 without directly touching the upper surface 20U of the mask 20. This allows the printing machine 10 to reduce damage to the upper surface 20U of the mask 20 when measuring the distance between the mask 20 and the plate 2. (Second example)

[0053] The screen printing machine 10, according to a second example, is demonstrated using the Fig. 4 and Fig. 6 described. The screen printing machine 10 according to the second example has the same configuration as the screen printing machine 10 according to the first example described above, except that the control device 50 of the screen printing machine 10 according to the second example performs a different plate printing process than the control device 50 of the first example.

[0054] As in the Fig. As shown in Figure 4, the print program 52 of the second example contains a displacement amount threshold Dth3 instead of the two displacement amount thresholds Dth1 and Dth2 of the first example. Furthermore, a handling process is registered in print program 52 of the second example. The displacement amount threshold Dth3 is a threshold for the control device 50 to determine whether the handling process is within the range specified in the Fig. The plate printing process shown in Figure 6 is to be carried out. The handling process comprises a print setting change process, a staple reset process, and a stop process. The print setting change process is a process for changing the print setting described above (53). The staple reset process is a process for resetting the staple pairs (16F and 16S) described above. The print stop process is a process for stopping the plate printing process. Before executing the plate printing process, the operator selects one of the three processes. The selected process is registered in the print program (52) as the handling process.

[0055] The plate printing process performed by the CPU 54 of the screen printing machine 10 according to the second example is described with reference to the Fig. 6 described. In S110 and S112, similar processes to those in S10 and S12 are described. Fig. 5. In S120, the CPU 54 compares the displacement values ​​obtained from the displacement sensor 46 with the displacement threshold Dth3. If the displacement values ​​do not include a displacement value exceeding the displacement threshold Dth3 (S120: YES), the CPU 54 proceeds to S130 and executes the printing operation. If the displacement values ​​do include a displacement value exceeding the displacement threshold Dth3 (S120: YES), the CPU 54 proceeds to S130. In S130, the CPU 54 determines whether the handling process registered in the print program 52 is the print stop process. If the handling process is a print stop process (S130: YES), the CPU 54 stops the plate printing process. As a result, the employee can confirm a part that is displaced beyond the displacement amount threshold Dth3 and correct the plate or mask in that part.

[0056] If the handling process registered in print program 52 is a print change process (S130: NO), the CPU 54 changes the print setting 53 in S132 and executes the print process (S140). The same process as in S32 is executed in S132. Fig. 5 executed.

[0057] If the handling process registered in print program 52 is the staple reset process (S130: NO), the CPU 54 resets the staple pairs 16F and 16S in S134 and returns to S120.

[0058] The special features of the printing press 10 described in the example are explained below. Instead of measuring the displacement of the target point (e.g., P1), the displacement sensor 46 can, for example, measure the displacements of four points on the same circumference around the target point P when the plate 2 is viewed from above. By measuring the displacements of the four points corresponding to the target point P, the length C1 of the gap around the target point P can be measured precisely. Furthermore, it is possible to measure on which side the plate 2 or the mask 20 is tilted around the target point P. In this modification, the four points are an example of the “multiple measurement target points”.

[0059] The nozzle 44 of the printing press 10 can, for example, only expel the air 60 in the direction of a target point P1. In this case, the output quantities V1 and V2 do not need to be stored in the target point table T1. In the present modification, the "output quantity determination section" can be omitted. In another modification, the opening areas A1 and A2 do not need to be stored in the target point table T1. In the present modification, the "opening area determination section" can be omitted.

[0060] The disk holder 14 need not include the clamp pair 16F and 16S. In this case, disk 2 can, for example, be located on an upper surface of the disk holder 14. In this case, the CPU 54 does not need to execute processes S20 and S22. In this modification, the "operation control section" can be omitted.

[0061] CPU 54 does not need to execute processes S30 and S32. In this modification, the "squeegee operation determination section" can be omitted.

[0062] Instead of the discharge rates or the opening areas, the discharge pressures can be stored in the target point table T1 in conjunction with the coordinates of target points P1 to P9. In this case, for example, the discharge pressures associated with target points P1 to P3 and P6 to P8 can be set higher compared to the discharge pressures associated with target points P4, P5, and P9. In a further modification, in addition to the discharge rates and opening areas, the discharge pressures can also be stored in the target point table T1 in conjunction with the coordinates of target points P1 to P9.

[0063] In the target point table T1 described above, the ejection quantity and the opening area are changed according to the distances between target points P1 to P9 and the bracket pair 16F and 16S. Alternatively, the ejection quantity and the opening area can be changed, for example, according to the distances between target points P1 to P9 and the mask holder 24. In this case, for example, a large ejection quantity V1 and a large opening area A1 can be set for target points P1 to P3 and P5 to P9 near the mask holder 24, while a small ejection quantity V2 and a small opening area A2 can be set for target point P4 farther from the mask holder 24.

[0064] The technical elements described in this description or the drawings are technically useful independently or in various combinations and are not limited to the combinations described in the claims as originally filed. Furthermore, the technology illustrated in this description or the drawings fulfills several purposes simultaneously, and the fulfillment of any one of these purposes is already technically useful.

[0065] For example, the present description also discloses a technical idea in which, in claim 3, the designation "The screen printing machine according to claim 1" is changed to "The screen printing machine according to claim 1 or 2". Likewise, a technical idea in which, in claim 4, the designation "The screen printing machine according to claim 1" is changed to "The screen printing machine according to any one of claims 1 to 3", a technical idea in which, in claim 5, the designation "The screen printing machine according to claim 1" is changed to "The screen printing machine according to any one of claims 1 to 4", a technical idea in which, in claim 6, the designation "The screen printing machine according to claim 1" is changed to "The screen printing machine according to any one of claims 1 to 5", and a technical idea in which, in claim 7, the designation "The screen printing machine according to claim 1" is changed to "The screen printing machine according to any one of claims 1 to 6" is disclosed. Reference symbol list 2 circuit boards 2U, 20U upper surface 4 high-pressure tanks 6 Adjustment valve 10 screen printing machines 12 Unit Drive Device 14 Tray holding device 15 pallet lifting device 16 Plate conveyor device 16F, 16S bracket 17 Plate conveyor device 20 masks 20D lower surface 21 print samples 22 Through hole 24 Mask holder 26 Holding mechanism 30 squeegee units 32 Lifting and lowering device 34 Angle adjustment device 36 squeegees 38 Solder paste 40 gap measuring unit 42 Lifting and lowering device 44 Air nozzle 45 Opening adjustment section 46 Displacement sensor 47 Opening 48 Drive device 50 Control device 51 storage 52 Print program 53 Print setting 54 CPU 55 Lifting amount determination section 56. Output quantity determination section 57 Opening area determination section 58 Operating Tax Section 59 Squeegee operation - Determination section 60 air A1, A2 Opening area C1 gap Dth1, Dth2, Dth3 Displacement magnitude threshold F1 pressure force P1 to P9, PA, PB Target point T1 Target Point Table V1, V2 output quantity

Claims

[1] A screen printing machine for printing viscous liquid onto a plate using a mask on which a printing pattern with a through-hole is formed, the screen printing machine comprising: a plate holding device configured to hold the plate; a mask holding device configured to hold an end portion of the mask along an outer circumference of the mask at a position above the plate held by the plate holding device; an air nozzle configured to expel air towards a target point on an upper surface of the mask, which is held in position above the plate, and A displacement magnitude measuring device configured to measure a displacement magnitude from one or more measurement target points, which are points on the upper surface before and after the ejection of air and correspond to the target point, in an up-down direction when the air is ejected from the air nozzle in the direction of the target point. [2] The screen printing machine according to claim 1, wherein the one or more measurement target points comprise the target point. [3] The screen printing machine according to claim 1, further comprising: a plate lifting device configured to raise the plate holding device when the viscous fluid is printed onto the plate; and a stroke amount determination section configured to determine the stroke amount of the plate holding device, wherein the lift amount determination section is configured to determine the lift amount based on the displacement amount of one or more target measurement points measured by the displacement amount determination section. [4] The screen printing machine according to claim 1, further comprising: an output quantity determination section for determining the amount of air emitted by the air nozzle, wherein the target point comprises a first target point and a second target point that differs from the first target point, the emission quantity determination section is configured to determine the emission quantity of air with respect to the second target point as a second emission quantity that differs from the first emission quantity of air with respect to the first target point, and The displacement measurement device is configured to measure the displacement of a first measurement target point corresponding to the first target point in the up-down direction and to measure a displacement of a second measurement target point corresponding to the second target point in the up-down direction. [5] The screen printing machine according to claim 1, further comprising: an opening area determination section configured to determine the opening area of ​​an air nozzle outlet opening, wherein the target point comprises a first target point and a second target point that differs from the first target point, the opening area determination section is configured to determine the opening area of ​​the outlet opening with respect to the second target point as a second opening area that differs from the first opening area of ​​the outlet opening with respect to the first target point, and The displacement measurement device is configured to measure the displacement of a first measurement target point corresponding to the first target point in the up-down direction and to measure a displacement of a second measurement target point corresponding to the second target point in the up-down direction. [6] The screen printing machine according to claim 1, further comprising: an operating control section configured to control the operation of the plate holding device, wherein the plate holding device includes a clamp configured to grip the end portion of the plate, and The operating control section is configured to cause the clamp to release the end part of the plate and subsequently to cause the clamp to grip the end part of the plate again when the displacement amount of the measurement target point measured by the displacement measurement device exceeds a predetermined threshold. [7] The screen printing machine according to claim 1, further comprising: a squeegee configured to fill the mask's through-hole with the viscous fluid; and a squeegee operation determination section configured to determine a pressure force with which the squeegee is pressed against the upper surface of the mask and the speed at which the squeegee is moved along the upper surface of the mask, wherein the squeegee operation determination section is configured to determine at least one of force and velocity based on the displacement magnitude of the measurement target point measured by the displacement magnitude measuring device.

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