Screen printing apparatus

Abstract

To improve accuracy in detecting a roll width of a solder roll.SOLUTION: A screen printing apparatus 1 comprises: a mask 12; a squeeze 25; a moving device 21 that moves the squeeze 25 from a printing start position S0 to a printing finishing position P0, in a longitudinal direction, on the mask; a sensor 26 that detects solder paste 70 on the mask; and a control part 50. The control part 50 scrapes the solder paste 70 on an upper surface of the mask, with the squeeze 25 to perform printing on a substrate PX overlapped on a lower surface of the mask, by moving the squeeze 25 in the longitudinal direction on the mask, using the moving device 21. After finishing the printing, the control part 50 makes the sensor 26 scan a solder roll 71 positioned at a front side of the printing finishing position P0 to detect both ends of the solder roll 71, in a moving direction of the squeeze, and calculates a roll width W in the longitudinal direction of the solder roll 71, on the basis of a position P1 where the solder roll 71 is detected by the sensor 26 and the printing finishing position P0.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present disclosure relates to a screen printing apparatus.

Background Art

[0002] A screen printing apparatus includes a mask, a squeegee, a moving device for moving the squeegee back and forth, etc. After supplying solder paste onto the upper surface of the mask, by moving the squeegee back and forth, the solder paste on the upper surface of the mask can be scraped by the squeegee and printed on a substrate mounted on the lower surface of the mask. Also, during the printing operation, the solder paste on the mask rolls by being pushed by the squeegee and is formed into a roll shape (solder roll).

[0003] Patent Document 1 below discloses detecting a solder roll formed into a roll shape by rolling during printing using a solder sensor. The solder sensor is an optical sensor, and after printing is completed, it scans the solder roll on the screen (mask) and measures the roll width of the solder roll by detecting the positions of both ends of the solder roll.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When detecting the roll width of a solder roll, if the solder sensor passes through the remaining scraped portion, the positions of both ends of the solder roll may be erroneously detected and become abnormal values. Also, not only when passing through the remaining scraped portion, but also when the shape of the solder roll collapses when the squeegee is raised after printing is completed, or when a part of the solder paste drops near the solder roll, there are similar problems.

[0006] An object of the present invention is to improve the detection accuracy of the roll width of a solder roll.

Means for Solving the Problems

[0007] A screen printing apparatus includes a mask, a squeegee, a moving device that moves the squeegee in the front-rear direction on the mask from a printing start position to a printing end position, a sensor that detects a solder paste on the mask, and a control unit.

[0008] The control unit uses the moving device to move the squeegee in the front-rear direction on the mask, thereby scraping the solder paste on the upper surface of the mask with the squeegee and printing it on a substrate reloaded on the lower surface of the mask.

[0009] After the printing is completed, the control unit scans a solder roll located on the front side of the printing end position in the squeegee moving direction with the sensor, detects both ends of the solder roll, and calculates the roll width in the front-rear direction of the solder roll based on the detection position of the solder roll by the sensor and the printing end position.

[0010] Note that during the printing operation, the solder roll rolls due to the solder paste on the mask being pushed by the squeegee and is formed into a roll shape.

[0011] In this configuration, since the roll width of the solder roll is calculated in consideration of the printing end position in addition to the detection result of the sensor, the roll width of the solder roll can be calculated more accurately and robustly than when calculating the roll width of the solder roll relying only on the detection result of the sensor.

[0012] When the detection position on the rear side of the solder roll by the sensor is in front of the printing end position of the squeegee, the control unit may calculate the roll width by a first detection method using the detection position on the rear side of the solder roll by the sensor as the start point of the solder roll. When the detection position on the rear side of the solder roll by the sensor is behind the printing end position of the squeegee, the control unit may calculate the roll width by a second detection method with the printing end position of the squeegee as the start point of the solder roll.

[0013] With this configuration, it is possible to suppress the roll width of the solder roll from being calculated as a value larger than the actual value due to the influence of the dropped solder or the remaining scraped part. As a result, it is possible to suppress the detection of abnormal values of the roll width, thereby suppressing the error stop of the production line and improving the tact.

[0014] The screen printing apparatus may include a selection input unit. The selection input unit enables selection of either a first detection method in which the detection position on the rear side of the solder roll by the sensor is the start point of the solder roll or a second detection method in which the printing end position of the squeegee is the start point of the solder roll, and the control unit may determine the detection method according to the operator's selection.

[0015] By the operator's selection, the detection method of the start point of the solder roll can be fixed during production, so that fluctuations in the roll width due to differences in the detection method can be suppressed.

[0016] The control unit calculates the roll width by both a first detection method in which the detection position on the rear side of the solder roll by the sensor is the start point of the solder roll and a second detection method in which the printing end position of the squeegee is the start point of the solder roll, and the control unit may determine the detection method of the start point of the solder roll based on the roll widths calculated by the two detection methods before the number of produced substrates reaches a predetermined number of produced substrates.

[0017] A detection method suitable for the characteristics of the substrate, mask, and solder can be automatically determined before the number of produced substrates reaches a predetermined number of produced substrates. Therefore, it is possible to suppress the stop of the printing apparatus and the delay of production due to the occurrence of errors.

[0018] The control unit may determine which detection method to use to detect the starting point of the solder roll, i.e., a first detection method in which the detection position on the rear side of the solder roll by the sensor is set as the starting point of the solder roll, or a second detection method in which the printing end position of the squeegee is set as the starting point of the solder roll, based on past production records.

[0019] In this configuration, by adopting a detection method for the starting point based on past records, the reliability of the calculation result can be enhanced. For example, when producing a substrate of the same variety as a variety with past production records, by using the same detection method as in the past to detect the starting point, fluctuations in the roll width due to differences in the detection method can be suppressed.

[0020] When there are production records of a substrate similar to the substrate to be produced in terms of production conditions, the control unit may detect the starting point of the solder roll for the substrate to be produced by using the detection method used in the production of the substrate with similar production conditions.

[0021] In this configuration, by selecting the detection method for a substrate with similar production conditions, the detection method to be used in production can be automatically determined.

[0022] The control unit may display on the display unit the calculation result of the first roll width calculated by the first detection method in which the detection position on the rear side of the solder roll by the sensor is set as the starting point of the solder roll, the calculation result of the second roll width calculated by the second detection method in which the printing end position of the squeegee is set as the starting point of the solder roll, and the selection menu for the two detection methods.

[0023] By the operator determining the detection method for the starting point himself / herself, he / she can be aware of which detection method is being adopted. Also, according to the operator's judgment, a more reliable detection method can be selected at any time.

[0024] The control unit may associate and store in the storage unit the unique ID of the substrate, the detection method for the starting point of the solder roll used in the production of the substrate, and the calculation result of the roll width in the front-rear direction of the solder roll.

[0025] It is possible to check the process by which it was determined that the roll width was appropriate from the data stored in association with the unique ID of the substrate.

Advantages of the Invention

[0026] According to the present invention, the detection accuracy of the roll width of the solder roll can be improved.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Mode for Carrying Out the Invention

[0028] <Embodiment 1> The screen printing apparatus (hereinafter also referred to as "printing apparatus") 1 will be described with reference to FIGS. 1 to 12. The moving direction of the squeegee 25 during printing is the front-rear direction, the longitudinal direction of the squeegee 25 is the left-right direction, and the vertical direction is the up-down direction.

[0029] 1. Overall configuration The screen printing apparatus 1 is an apparatus for printing solder paste 70 on the surface of a plate-shaped substrate PX. As shown in FIG. 1, the printing apparatus 1 includes a box-shaped housing 10. An opening through which the substrate PX is carried in is formed in the right wall of the housing 10, and an opening through which the substrate PX is carried out is formed in the left wall. The substrate PX is carried into the interior of the housing 10 through the opening in the right wall, and is carried out to the left after the solder paste 70 is printed.

[0030] FIG. 2 is a plan view of the screen printing apparatus 1, and FIG. 3A is a cross-sectional view of the screen printing apparatus 1. The printing apparatus 1 includes a pair of front and rear conveyors 11 for conveying the substrate PX, a mask 12, a pair of left and right mask holders 13, a substrate support device 16, a moving device 21, a front and rear moving device 22, a squeegee head 23, and the like.

[0031] The mask 12 includes a frame-shaped mask frame 12A and a sheet-shaped stencil 12B stretched inside the mask frame 12A. The stencil 12B is made of iron, aluminum, stainless steel, etc., and has printing openings (not shown) corresponding to the pattern of the solder paste 70 to be printed on the substrate PX.

[0032] The conveyor 11 is provided with a conveyor belt that circulates and moves in the left - right direction. The conveyor 11 is driven by a conveyor drive motor (not shown) and carries the substrate PX to be printed into and out of the printing apparatus 1.

[0033] As shown in FIG. 3A, the substrate support device 16 has a backup plate 16A that can be raised and lowered below the mask 12. The substrate PX carried into the printing apparatus 1 is placed on the upper surface of the backup plate 16A. Then, after the substrate support device 16 moves to a predetermined printing position, the backup plate 16A is raised to bring the substrate PX into close contact with the lower surface of the mask 12.

[0034] As shown in FIG. 3A, the mask holder 13 is L - shaped when viewed from the left - right direction. The mask holder 13 sandwiches the mask frame 12A in the front - rear direction and fixes the mask 12 to the printing apparatus 1.

[0035] As shown in FIGS. 2 and 4A, the moving device 21 is in the shape of a rectangular parallelepiped that is long in the left - right direction and supports the squeegee head 23 so that it can move up and down. The forward - backward moving device 22 has a ball screw 27 and a first motor 28. The ball screw 27 is a ball screw mechanism that moves the moving device 21 and the squeegee head 23 in the front - rear direction.

[0036] By driving the first motor 28, a propulsive force in the front - rear direction is obtained from the ball screw 27, and the moving device 21 and the squeegee head 23 reciprocate in the front - rear direction.

[0037] The moving device 21 incorporates a second motor 30. By driving the second motor 30, the squeegee head 23 can be moved in the vertical direction with respect to the moving device 21.

[0038] As shown in FIG. 4A, the squeegee head 23 rotatably supports the squeegee 25 via the arm portion 29. The squeegee head 23 incorporates a third motor 31, and by the rotation of the motor, the squeegee 25 can be rotated about the rotation axis 29A. As shown in FIG. 3A, the squeegee 25 has a long shape in the left-right direction. When the squeegee head 23 is lowered to the position shown in FIG. 3A, the tip of the squeegee 25 contacts the surface of the stencil 12B, and the printing operation can be performed.

[0039] In addition, the squeegee head 23 is also provided with a supply unit that supplies the solder paste 70 to the upper surface of the stencil 12B.

[0040] 2. Electrical Configuration of the Printing Apparatus 1 As shown in FIG. 5, the printing apparatus 1 includes a display unit 14, a control unit 50, and an input unit 51. The control unit 50 has a CPU 52, a RAM 53, and a storage unit 54. The display unit 14, the input unit 51, the moving device 21, the sensor 26, etc. are connected to the control unit 50.

[0041] The storage unit 54 stores various programs and data executed by the CPU 52. The display unit 14 is a display device such as a liquid crystal display. The input unit 51 is an input device such as a touch panel, a mouse, or a keyboard.

[0042] The control unit 50 controls the first motor 28 and the second motor 30 to move the squeegee 25 in the front-rear direction and the up-down direction. Also, the control unit 50 controls the third motor 31 to rotate the squeegee 25 about the rotation axis 29A.

[0043] In addition, the storage unit 54 has information on the dimensions of each part of the squeegee head 23, the squeegee 25, and the arm portion 29. Based on this information and the information on the axis values of each motor, the control unit 50 calculates the position and angle of the squeegee 25 on the mask 12.

[0044] 3. Printing Process and Formation of the Solder Roll 71 With reference to FIG. 4A, the printing process and the formation of the solder roll 71 will be described. Before printing starts, the substrate PX is reloaded onto the lower surface of the stencil 12B, and solder paste 70 is supplied onto the upper surface of the stencil 12B by a supply unit mounted on the squeegee head 23.

[0045] As shown in FIG. 4A, when the squeegee 25 is moved forward (to the left in FIG. 4) from the printing start position S0, the solder paste 70 is pushed forward by the squeegee 25.

[0046] The solder paste 70 is pushed by the squeegee 25 and moves on the stencil 12B while rolling. The solder paste 70 is filled into the printing openings provided in the stencil 12B and printed on the substrate PX.

[0047] Due to the rolling during printing, a roll-shaped solder roll 71 is formed in front of the squeegee 25. When the tip 25A of the squeegee 25 reaches the printing end position P0 (see FIG. 4B), the printing process ends.

[0048] FIG. 4B shows the positional relationship between the solder roll 71 and the squeegee 25 at the end of printing. In the squeegee movement direction, the solder roll 71 is located at the position of the printing end position P0 of the squeegee 25 or in front of it.

[0049] 4. Detection of the solder roll 71 by the sensor 26 As shown in FIG. 6, the sensor 26 is attached to the squeegee head 23. In this embodiment, the sensor 26 is attached at a position away from the center of the squeegee head 23, specifically, at a position near the front of the right wall.

[0050] By driving the first motor 28 and the third motor 31, the sensor 26 can move integrally with the squeegee head 23 in the front-rear direction and the up-down direction.

[0051] The sensor 26 is an optical sensor and has a light-emitting element that emits laser light and a light-receiving element that receives the laser light.

[0052] The sensor 26 is located above the stencil 12B, irradiates laser light from above toward the stencil 12B, and receives the reflected light. In the case of this embodiment, when the received light amount is less than the threshold value (when there is solder), the sensor 26 outputs an ON signal, and when the received light amount is greater than or equal to the threshold value (when there is no solder), the sensor 26 outputs an OFF signal.

[0053] As shown in FIG. 7, after the printing process is completed, after raising the squeegee head 23, it is retracted, and the sensor 26 is moved above the detection start position M1.

[0054] Thereafter, while irradiating laser light toward the upper surface of the stencil 12B, the squeegee head 23 is moved forward, and the sensor 26 is moved from the detection start position M1 to the detection end position M2.

[0055] Thereby, the solder roll 71 can be scanned with the laser light and the solder roll 71 can be detected. Note that the printing end position P0 of the squeegee 25 is included in the detection range M0 of the sensor 26.

[0056] FIG. 8 shows the output signal of the sensor 26 when scanning the solder roll 71. The detection position P1 is the position where the sensor output switches from OFF to ON, and the detection position P2 is the position where the sensor output switches from ON to OFF. Note that when the sensor output at the detection start position M1 is ON, the detection start position M1 is set as the detection position P1.

[0057] The detection position P1 is the detection position on the rear side of the solder roll 71 and is the starting point in the calculation of the roll width W. The detection position P2 is the detection position on the front side of the solder roll 71 and is the end point in the calculation of the roll width W. Then, by obtaining the distance H1 between the two points P1 and P2, the roll width W of the solder roll 71 in the front-rear direction can be calculated.

[0058] W = H1 (1)

[0059] From the calculation result of the roll width W, the remaining amount of the solder paste 70 can be estimated. After the printing process is completed, the roll width W is calculated. When the remaining amount decreases, by replenishing the solder paste 70 onto the mask 12, the occurrence of printing defects due to insufficient solder can be prevented. As described above, the detection method of the roll width W with the detection position P1 being the starting point of the solder roll 71 is defined as the first detection method.

[0060] <False detection of sensor 26> When there is a scraping residue portion 72 of the solder paste 70, as shown in FIG. 9, the two-point distance H1 calculated by the sensor 26 is larger than the actual roll width W. This is because the sensor output becomes ON not only for the solder roll 71 but also for the scraping residue portion 72.

[0061] False detection of the sensor 26 may also occur when there is dropped solder 74 or when a corner portion 75 is formed on the solder roll 71 (see FIGS. 10 and 11).

[0062] As shown in FIG. 4B, in the squeegee moving direction, since the solder roll 71 is formed in front of the squeegee 25, when there is no scraping residue portion 72 or dropped solder 74, the detection position P1 of the solder roll 71 by the sensor 26 is located in front of the printing end position P0 of the squeegee 25.

[0063] On the other hand, when the detection position P1 of the solder roll 71 by the sensor 26 is behind the printing end position P0 of the squeegee 25, it is highly likely that it is caused by the scraping residue portion 72 or dropped solder 74.

[0064] Therefore, when the detection position P1 is behind the printing end position P0, as shown in FIGS. 9 to 11, the starting point of the solder roll 71 is set to the printing end position P0 instead of the detection position P1. Then, the two-point distance H2 between P0 and P2 is defined as the roll width W of the solder roll 71.

[0065] W = H2 (2)

[0066] When the detection position P1 is behind the printing end position P0, by setting the start point of the solder roll 71 as the printing end position P0, the influence of the remaining part 72 and the like can be excluded, and the roll width W can be accurately calculated. In this way, the detection method of the roll width W with the printing end position P0 as the start point of the solder roll 71 is defined as the second detection method.

[0067] FIG. 12 is a flowchart of the solder roll calculation process. After the printing process is completed, the control unit 50 scans the solder roll 71 with the sensor 26 and acquires the data of the detection result of the sensor 26 (S10). At this time, the data of the printing end position P0 of the squeegee 25 is also acquired.

[0068] Thereafter, the control unit 50 determines whether solder exists in the detection range M0 (S20). The presence or absence of solder can be determined from the output signal of the sensor 26.

[0069] If no solder exists (S20: NO), the calculation process ends due to a measurement error (S25). If solder exists (S20: YES), the control unit 50 determines whether the output signal at the detection end position M2 of the sensor 26 is OFF (S30).

[0070] If the output signal of the sensor 26 is ON (S30: NO), it is determined that the front end of the solder roll 71 is in front of the detection end position M2, and the calculation process ends due to a measurement error (S35).

[0071] If the output signal of the sensor 26 is OFF (S30: YES), the control unit 50 determines the end point of the solder roll 71 as the detection position P2 on the front side of the sensor 26 (S40).

[0072] Next, the control unit 50 determines whether the detection position P1 of the sensor 26 is in front of the printing end position P0 (S50).

[0073] If the detection position P1 of the sensor 26 is in front of the printing end position P0 (S50: YES), the control unit 50 determines the start point of the solder roll 71 as the detection position P1 of the sensor 26 (S60).

[0074] After that, the control unit 50 calculates the distance H1 between the two points of the end point (detection position P2) determined in S40 and the start point (detection position P1) determined in S60, and sets the calculated distance H1 between the two points as the roll width W (S70).

[0075] On the other hand, when the detection position P1 of the sensor 26 is behind the printing end position P0 (S50: NO), the control unit 50 determines the start point of the solder roll 71 as the printing end position P0. (S55).

[0076] After that, the control unit 50 calculates the distance H2 between the two points of the end point (detection position P2) determined in S40 and the start point (printing end position P0) determined in S55, and sets the calculated distance H2 between the two points as the roll width W (S70).

[0077] When calculating the roll width W, the control unit 50 determines whether the value of the roll width W is appropriate (S80). Specifically, it determines whether the roll width W is within the appropriate range.

[0078] When the roll width W is within the appropriate range (S80: YES), the control unit 50 ends the calculation process. When the roll width W is outside the appropriate range (S80: NO), it is regarded as a roll width error and the calculation process is ended (S85).

[0079] 6. Effect Explanation This configuration does not rely only on the detection positions P1 and P2 of the solder roll 71 by the sensor 26, but takes into account the printing end position P0 of the squeegee 25 to obtain the end of the solder roll 71 and calculates the roll width W. Therefore, the roll width W of the solder roll 71 can be calculated accurately and robustly.

[0080] As shown in FIG. 3B, when the length of the substrate PX in the left-right direction to be printed is small, the stencil 12C of the portion not overlapping with the substrate PX bends, so that the remaining portion 72 is likely to occur. In the configuration of the present embodiment, even if there is a remaining portion 72, the roll width W can be accurately calculated.

[0081] In this configuration, since the sensors 26 can also be arranged at both ends of the squeegee head 23 where it is likely to overlap with the remaining portion 72 (see FIG. 6), the constraints on the mounting positions of the sensors 26 are relaxed. Also, when there is dropped solder 74 near the solder roll 71 (see FIG. 10) or when a corner 75 is formed on the solder roll 71 (see FIG. 11), the roll width W of the solder roll 71 can be accurately calculated without being affected by them.

[0082] <Embodiment 2> Embodiment 2 will be described with reference to FIGS. 13 and 14. In Embodiment 2, the control unit 50 displays the machine setting screen 14A of the printing apparatus 1 on the display unit 14 of the printing apparatus 1. The machine setting screen 14A includes the setting items (left column in FIG. 13) of the printing apparatus 1 and the display items of the setting contents (right column in FIG. 13).

[0083] The setting items include "Detection method for roll width measurement start point". When the operator operates the input unit 51 to select this item, a selection menu 15 is displayed within the display items in the right column. The selection menu 15 is a menu for selecting the sensor detection position P1 and the printing end position P0, and corresponds to the "selection input unit" of the present invention.

[0084] When the operator selects either the sensor detection position P1 or the printing end position P0 from the selection menu 15, in the subsequent calculation process, the control unit 50 calculates the roll width W with the start point selected by the operator as the start point of the solder roll 71.

[0085] In this configuration, since the operator can arbitrarily select the detection method for the start point of the solder roll 71, fluctuations in the roll width W caused by a change in the detection method during production can be suppressed.

[0086] FIG. 14 is a flowchart of the solder roll calculation process. The solder roll calculation process of Embodiment 2 is different from that of Embodiment 1 in that it has a step of S45 instead of S50 to S70.

[0087] <Embodiment 3> In Embodiment 3, until reaching a predetermined number of judgment sheets from the start of production, it is automatically determined which of the following two calculation methods is used to calculate the roll width W of the solder roll 71.

[0088] (1) Calculation method using the distance H1 between two points (2) Calculation method using the distance H2 between two points

[0089] In the following description, the width of the solder roll 71 calculated by the method of (1) is defined as the first roll width W1, and the width of the solder roll 71 calculated by the method of (2) is defined as the second roll width W2. Also, the internal variable Q is a variable that determines the starting point of the solder roll 71, and the initial setting is set to the detection position P1.

[0090] Hereinafter, the calculation process of the roll width W will be described with reference to the flowchart of FIG. 15. Since S10 to S40 are the same as those in Embodiment 1, the description thereof will be omitted.

[0091] When determining the end point of the solder roll 71 at S40, the control unit 50 then proceeds to S250.

[0092] <Processing until the calculation method is determined> When proceeding to S250, the control unit 50 determines the production number X and the internal variable Q. Specifically, it is determined whether the current production number X is less than or equal to the judgment number and whether the internal variable Q is at the detection position P1.

[0093] Since the initial setting of the internal variable Q is the detection position P1, at the first production after the start of production, S250: YES is satisfied and the process proceeds to S265.

[0094] When proceeding to S265, the control unit 50 calculates two types of roll widths W1 and W2. Then, the control unit 50 determines whether the difference D between the roll widths W1 and W2 is less than or equal to the threshold value TH (S270).

[0095] When the difference D is less than or equal to the threshold value (S270: YES), the control unit 50 determines whether the first roll width W1 is appropriate (S275). If the first roll width W1 is appropriate (S275: YES), the calculation process ends.

[0096] When the first roll width W1 is appropriate, the internal variable Q is maintained at the detection position P1. Therefore, even in the production of the second and subsequent sheets, the calculation process proceeds in the above flow.

[0097] And until the number of printed sheets X of the substrate PX reaches the determined number of sheets, if both are determined to be YES in S270 and S275, the control unit 50 determines the calculation method of the roll width W as the calculation method in (1). In this case, the internal variable Q is maintained at the detection position P1.

[0098] On the other hand, when the difference D is greater than the threshold value TH (S270: NO), the control unit 50 determines whether the second roll width W2 is appropriate (S271).

[0099] When the second roll width W2 is appropriate (S271: YES), the control unit 50 determines the calculation method of the second roll width W as the calculation method in (2). Accordingly, the control unit 50 changes the internal variable Q from the detection position P1 to the printing end position P0 (S272).

[0100] If the roll widths W1 and W2 are not appropriate (S271, S275: NO), a roll width error is set (S276).

[0101] <Processing after determining the calculation method> When the calculation method in (1) is determined, when the number of produced sheets X becomes equal to or more than the determined number of sheets, in S250, a NO determination is made. Also, when the calculation method in (2) is determined, since the internal variable Q reaches the printing end position P0, in S250, a NO determination is made. Therefore, in both cases, the process proceeds to S280, and the control unit 50 calculates the roll width W according to the internal variable Q.

[0102] That is, when the internal variable Q is at the detection position P1, the first roll width W1 is calculated based on the distance H1 between two points. On the other hand, when the internal variable Q is at the printing end position P0, the second roll width W2 is calculated based on the distance H2 between two points.

[0103] Then, it is determined whether the calculated roll width W (W1 or W2) is appropriate (S280). If the roll width W is appropriate (S285: YES), the calculation process ends. If the roll width W is not appropriate (S285: NO), a roll width error is set (S286).

[0104] It is desirable to calculate the roll width W using the method (1) that uses the detection results of the sensor 26 at both the start point and the end point. However, depending on the type of the substrate PX to be printed, there may be a remaining portion 72, and if roll width errors occur frequently, it may hinder production. Also, the occurrence of roll width errors may be caused by the characteristics of the mask and the characteristics of the solder (including the conditions on that day).

[0105] On the other hand, if the roll width W is calculated by the method (2) that uses the printing end position P0 as the start point, the influence of the remaining portion 72 and the like can be excluded.

[0106] In this configuration, according to the production state (characteristics of the substrate, characteristics of the mask, characteristics of the solder), the calculation method of the roll width W is automatically determined. Thereby, the occurrence of roll width errors can be suppressed and the tact can be improved.

[0107] <Embodiment 4> In Embodiment 4, based on the past production results, it is determined which of the first detection method and the second detection method is used to detect the start point of the solder roll 71.

[0108] The printing apparatus 1 stores production result information in the storage unit 54. The production result information is information that associates the type of the substrate produced in the past with the calculation method of the roll width W used in the production of that type.

[0109] FIG. 16 is a flowchart of the solder roll calculation process according to Embodiment 4. The solder roll calculation process of Embodiment 4 differs from the solder roll calculation process of Embodiment 3 in the steps after S350.

[0110] After determining the end point of the solder roll 71 at the detection position P2 (S40), the control unit 50 proceeds to S350. In S350, the control unit 50 accesses the storage unit 54 and determines whether there is a production record of a substrate of the same type as the substrate to be produced this time.

[0111] If the storage unit 54 has production record information of the same type (S355: YES), the control unit 50 reads from the storage unit 54 the detection method of the start point of the solder roll 71 used in the production of the same type and applies it to the substrate to be produced (S355). Then, the roll width W is calculated using the applied start point (S360).

[0112] If there is no production record of the same type (S355: NO), the process proceeds to S250 of Embodiment 3, and the start point is automatically determined to calculate the roll width W. Note that the initial setting of the internal variable Q in Embodiment 4 is set at the detection position P1 as in Embodiment 3.

[0113] With this configuration, based on past production records, the detection method of the start point is determined, so the reliability of the calculated roll width W can be improved. Also, by making the detection method the same among the same types, fluctuations in the roll width W can be suppressed.

[0114] <Embodiment 5> In Embodiment 5, when there is a production record of a substrate with production conditions similar to the substrate to be produced, the detection method used in the production of the substrate with similar production conditions is used to detect the start point of the solder roll 71 on the substrate to be produced.

[0115] The printing apparatus 1 stores information on production conditions in addition to production record information in the storage unit 54. The information on production conditions includes, for example, the following information. The information on production conditions is linked to the type of the substrate PX.

[0116] (1) Printing control method ( squeegee lifting angle, printing speed ) (2) Type of squeegee ( variety, lot number ) (3) Type of solder paste ( variety, lot number, manufacturing date ) (4) Substrate size (5) Mask size (6) Mask elapsed time, manufacturer name

[0117] Figure 17 is a flowchart of the solder roll calculation process according to Embodiment 5. The solder roll calculation process according to Embodiment 5 differs from the solder roll calculation process according to Embodiment 4 in the steps after S350.

[0118] If there is no production result information for a substrate of the same variety as the substrate to be produced this time ( S350: NO ), the control unit 50 compares the production conditions of the substrate to be produced with the production conditions of different substrates produced in the past.

[0119] If there is a production result for a substrate with production conditions similar to those of the substrate to be produced ( S451: YES ), the control unit 50 reads out the detection method used for the substrate with similar production conditions from the storage unit 54 and applies it to the substrate to be produced ( S452 ). Then, the roll width W is calculated using the applied detection method ( S360 ).

[0120] If there is no production result for a substrate with similar production conditions ( S451: NO ), the process proceeds to S250 of Embodiment 3, and the starting point is automatically determined to calculate the roll width W. Note that the initial setting of the internal variable Q in Embodiment 5 is set at the detection position P1, the same as in Embodiment 3.

[0121] In addition, the "similarity of production conditions" is determined by the control unit 50 by comparing a plurality of items included in the production conditions of the substrate to be produced and the substrates produced in the past. The criterion for determining similarity or not is, for example, that a predetermined ratio or more of the items included in the production conditions match, or that the difference in numerical values is smaller than a predetermined threshold value. The operator can arbitrarily set the criterion for determining similarity or not.

[0122] In this configuration, even if there is no production record of a substrate of the same type as the substrate to be printed, the detection method used in production can be automatically determined by selecting a detection method for substrates with similar production conditions. Therefore, the labor of the operator can be reduced. In addition, since the roll width W can be accurately calculated using the determined starting point, it is possible to take measures before the amount of solder becomes too small or production stops due to an error.

[0123] <Embodiment 6> In Embodiment 6, the calculation result of the first roll width W1 calculated by the first detection method and the calculation result of the second roll width W2 calculated by the second detection method are displayed on the display unit 14 to prompt the operator to select a detection method.

[0124] FIG. 18 is a flowchart of the solder roll calculation process of Embodiment 6. The solder roll calculation process of Embodiment 6 differs from the solder roll calculation process of Embodiment 1 in the steps after S550.

[0125] After determining the end point of the solder roll 71 as the detection position P2 (S40), the control unit 50 calculates the roll width W of the solder roll 71 by two calculation methods, the first detection method and the second detection method.

[0126] Next, the control unit 50 creates data of the graph 17 of the first roll width W1 calculated by the first detection method and the second roll width W2 calculated by the second detection method, and displays it on the display unit 14 (FIG. 19, S555). The horizontal axis of the graph 17 is the number of measurements, and the vertical axis is the roll width W.

[0127] Next, the control unit 50 determines whether the first roll width W1 and the second roll W2 are appropriate (S560). If both the roll widths W1 and W2 are appropriate (S560: YES), it is determined whether the production number X of the substrate PX has reached the determination number (S570).

[0128] The determination number is any number of 1 or more. The production number X is 0 at the start of production and is incremented each time the printing process is executed.

[0129] When the number of produced substrates X is less than the number of substrates for determination (S570: NO), the calculation process ends, the printed substrate PX is carried out of the printing apparatus 1, the next substrate PX is carried in, and the printing process is performed.

[0130] When the number of produced substrates X is greater than or equal to the number of substrates for determination (S570: YES), the control unit 50 displays the selection menu 18 of the detection method on the display unit 14 in addition to the graph 17 (S580).

[0131] The operator can select the detection method to be applied to the calculation of the roll width W in the subsequent production from the selection menu 18.

[0132] When the detection method is selected, in the subsequent production, the control unit 50 calculates the roll width W using the detection method selected by the operator.

[0133] On the other hand, in S560, when at least one of the roll widths W1 and W2 is not appropriate (S560: NO), a roll width error occurs (S565). Then, an error message is displayed on the display unit 14 (S566).

[0134] In this configuration, since the operator can refer to the graph 17 showing the transition of the roll widths W1 and W2, a more reliable detection method can be selected at any time.

[0135] Further, the display unit 14 may be a display device that is connected to the printing apparatus 1 by wire or wirelessly in addition to the display device provided in the printing apparatus 1 described above. For example, it may be a display of a tablet terminal carried by the operator or a display provided in the centralized management room of the factory. In such a configuration, the operator can select the detection method even when being away from the printing apparatus 1.

[0136] <Embodiment 7> Embodiment 7 associates and stores the ID unique to the substrate PX, the detection method of the start point of the solder roll 71 used in the production of the substrate PX, and the calculation result of the roll width W.

[0137] Specifically, an identifier 19 different for each substrate is attached to the surface of the substrate PX (see FIG. 2). The identifier 19 is, for example, a barcode, a two-dimensional code, a character string, or the like. A substrate ID unique to each substrate is recorded in the identifier 19. The substrate ID can be read from the identifier 19 by visual inspection by an operator or using a reading device. The read substrate ID is input to the control unit 50.

[0138] The control unit 50 associates and stores in the storage unit 54 the substrate ID of the produced substrate PX, the calculated roll width W, and the detection method of the start point used in the calculation process.

[0139] An example of the information stored in the storage unit 54 is shown in FIG. 20. For each produced substrate, the substrate ID, the roll width W, and the start point detection method are stored in an associated state. With this configuration, even after production is completed, by accessing the storage unit 54, it is possible to confirm the process including the detection method that led to the determination that the roll width W is appropriate.

[0140] <Other Embodiments> The present invention is not limited to the embodiments described above with reference to the description and drawings. For example, the following embodiments are also included in the technical scope of the present invention. (1) In the above embodiment, as an example of the selection input unit, the selection menu 15 displayed on the machine setting screen is exemplified. However, for example, a toggle switch or a push button switch may be used to select either the detection position P1 by the sensor 26 or the printing end position P0.

[0141] (2) In the above embodiment, when the detection position P1 by the sensor 26 is behind the printing end position P0, instead of the detection position P1, the printing end position P0 is used as the start point of the solder roll 71, and the roll width W is calculated. The start point of the solder roll 71 is not limited to the printing end position P0 and may be any position between the detection position P1 and the printing end position P0.

[0142] (3) In the above embodiment, the case where the squeegee 25 is moved from the rear to the front for printing is exemplified, but the moving direction of the squeegee is not limited to this. The printing process may be performed by moving the squeegee 25 from the front to the rear. In this case, the arm portion 29 rotates the squeegee 25 around the rotation axis 29A to adjust the angle between the stencil 12B and the squeegee 25.

[0143] (4) In the above embodiment, the sensor 26 outputs an ON signal when there is solder and an OFF signal when there is no solder. The ON / OFF of the sensor output may be reversed. That is, an OFF signal may be output when there is no solder, and an ON signal may be output when there is solder.

Explanation of Reference Numerals

[0144] 1 Screen printing apparatus 12 Mask 21 Moving device 25 Squeegee 26 Sensor 50 Control unit 70 Solder paste 71 Solder roll PX Substrate P0 Printing end position P1, P2 Detection positions W Roll width

Claims

1. A screen printing apparatus, comprising: a mask; a squeegee; a moving device configured to move the squeegee in the front - rear direction from a printing start position to a printing end position on the mask; a sensor configured to detect a solder paste on the mask; a control unit; The control unit moves the squeegee in the front - rear direction on the mask using the moving device, thereby scraping the solder paste on the upper surface of the mask with the squeegee and printing it on a substrate re - mounted on the lower surface of the mask; After printing is completed, the control unit scans a solder roll located in front of the printing end position in the squeegee moving direction with the sensor to detect both ends of the solder roll; A screen printing apparatus that calculates a roll width in the front - rear direction of the solder roll based on a detection position of the solder roll by the sensor and the printing end position.

2. The screen printing apparatus according to claim 1, When a detection position on the rear side of the solder roll by the sensor is in front of the printing end position of the squeegee, the control unit calculates the roll width by a first detection method using the detection position on the rear side of the solder roll by the sensor as a start point of the solder roll; When a detection position on the rear side of the solder roll by the sensor is behind the printing end position of the squeegee, the control unit calculates the roll width by a second detection method using the printing end position of the squeegee as a start point of the solder roll.

3. The screen printing apparatus according to claim 1, comprising a selection input unit; The selection input unit enables selection of either a first detection method in which a detection position on the rear side of the solder roll by the sensor is used as a start point of the solder roll or a second detection method in which a printing end position of the squeegee is used as a start point of the solder roll; The control unit determines a detection method according to an operator's selection.

4. The screen printing apparatus according to claim 1, The control unit calculates the roll width by both a first detection method in which a detection position on the rear side of the solder roll by the sensor is used as a start point of the solder roll and a second detection method in which a printing end position of the squeegee is used as a start point of the solder roll. The control unit is a screen printing apparatus that determines a detection method for the start point of the solder roll based on the roll widths calculated by two detection methods until the production quantity of the substrate reaches a predetermined production quantity.

5. The screen printing apparatus according to claim 1, wherein the control unit determines which detection method to use to detect the start point of the solder roll, based on past production records, from among a first detection method in which the detection position on the rear side of the solder roll by the sensor is set as the start point of the solder roll and a second detection method in which the printing end position of the squeegee is set as the start point of the solder roll.

6. The screen printing apparatus according to claim 5, wherein when there is a production record of a substrate similar to the substrate to be produced and the production conditions, the control unit uses the detection method used in the production of the substrate with similar production conditions to detect the start point of the solder roll for the substrate to be produced.

7. The screen printing apparatus according to claim 1, wherein the control unit displays on a display unit a calculation result of a first roll width calculated by a first detection method in which the detection position on the rear side of the solder roll by the sensor is set as the start point of the solder roll, a calculation result of a second roll width calculated by a second detection method in which the printing end position of the squeegee is set as the start point of the solder roll, and a selection menu for the two detection methods.

8. The screen printing apparatus according to any one of claims 1 to 7, wherein the control unit associates and stores in a storage unit a substrate ID unique to the substrate, a detection method for the start point of the solder roll used in the production of the substrate, and a calculation result of the roll width in the front-rear direction of the solder roll.

Images