阅读说明：本技术 丝网印刷机 (Screen printing machine ) 是由 高津郁雄 于 2018-10-17 设计创作，主要内容包括：本说明书所公开的丝网印刷机使用形成有由贯通孔构成的印刷图案的掩模对基板进行粘性流体的印刷。该丝网印刷机具备接触部件。另外,该丝网印刷机利用驱动装置使接触部件向接触部件的前端与粘性流体接触的接触位置和接触部件的前端从粘性流体分离的分离位置移动。另外,该丝网印刷机具备计测装置,在通过驱动装置使接触部件从接触位置移动到分离位置时,该计测装置计测从接触部件的前端垂下的粘性流体的长度。进而,该丝网印刷机通过控制装置,基于计测装置的计测结果来设定对基板进行粘性流体的印刷时的印刷条件。(The screen printer disclosed in the present specification performs printing of a viscous fluid on a substrate using a mask on which a print pattern including through holes is formed. The screen printer includes a contact member. In addition, the screen printing machine moves the contact member by the driving device to a contact position where the leading end of the contact member is in contact with the viscous fluid and a separation position where the leading end of the contact member is separated from the viscous fluid. The screen printing machine further includes a measuring device that measures a length of the viscous fluid hanging down from the tip of the contact member when the contact member is moved from the contact position to the separation position by the driving device. Further, the screen printer sets, by the control device, printing conditions for printing the viscous fluid on the substrate based on the measurement result of the measurement device.)

1. A screen printer for printing a viscous fluid on a substrate using a mask having a printing pattern formed of through holes,

the screen printer includes:

a contact member;

a drive device capable of moving the contact member to a contact position where a leading end of the contact member is in contact with the viscous fluid and a separation position where the leading end of the contact member is separated from the viscous fluid;

a measuring device that measures a length of the viscous fluid hanging down from a tip of the contact member when the contact member is moved from the contact position to the separation position by the driving device; and

and a control device for setting a printing condition for printing the viscous fluid on the substrate based on a measurement result of the measurement device.

2. The screen printing machine according to claim 1,

the mask has a surface to which the viscous fluid is supplied,

the contact member is a squeegee for filling the viscous fluid into the through-hole of the mask,

the driving device is capable of moving the squeegee at a predetermined speed in a direction horizontal to the surface of the mask and at a predetermined speed in a direction orthogonal to the surface of the mask while pressing the squeegee against the surface of the mask at a predetermined pressure at a predetermined angle with respect to the surface of the mask,

the contact position is a position where a leading end of the squeegee contacts the viscous fluid supplied to the surface of the mask,

the separation position is a position at which the viscous fluid supplied to the surface of the mask is separated from the viscous fluid hanging from the leading end of the squeegee.

3. The screen printing machine according to claim 2,

the measurement device measures a length of the viscous fluid extending from the squeegee toward the mask when the squeegee is moved in a direction orthogonal to the surface of the mask after the squeegee fills the through-hole of the mask with the viscous fluid.

4. The screen printing machine according to any of claims 1 to 3,

the measuring device measures a first length of the viscous fluid hanging down from a tip of the contact member when the contact member is moved from the contact position to the separation position at a first speed by the driving device, and,

the measurement device measures a second length of the viscous fluid hanging down from a tip of the contact member when the contact member is moved from the contact position to the separation position at a second speed different from the first speed by the drive device,

the control device sets a printing condition for printing the viscous fluid on the substrate based on the first length and the second length measured by the measuring device.

5. The screen printing machine according to any of claims 1 to 4,

the screen printing machine further includes an output device that outputs a signal indicating occurrence of an abnormality based on a measurement result of the measurement device.

Technical Field

The technology disclosed in the present specification relates to a screen printer that prints a viscous fluid on a substrate using a mask on which a print pattern including through holes is formed.

Background

Patent document 1 discloses a solder printer. The solder printer includes a mask disposed on a circuit board and a squeegee for printing cream solder (an example of viscous fluid) into the mask. The cream solder is printed on the object to be printed by moving the squeegee along the surface of the mask to which the cream solder is supplied. Such a printing method using a mask and a squeegee is generally called screen printing.

In screen printing, if the viscosity of the viscous fluid is not appropriate, printing defects are likely to occur. Further, the appropriate printing conditions vary depending on the viscosity of the viscous fluid to be printed. Wherein the viscosity of the viscous fluid varies with time and also with temperature. Therefore, in the solder printer of patent document 1, it is determined whether or not the viscosity of the cream solder on the mask is normal based on the torque of the motor required for the squeegee to move the cream solder on the mask.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-039877

Disclosure of Invention

Problems to be solved by the invention

In the technique of patent document 1, the viscosity of the viscous fluid is determined based on the torque of a motor that moves the squeegee. The torque of the motor when the squeegee is moved depends on not only the viscosity of the viscous fluid but also other changing factors such as the friction coefficient between the squeegee and the mask. In addition, other elements have a greater influence on the motor torque than the viscosity of the viscous fluid. Therefore, the present specification provides a screen printer capable of measuring the viscosity of a viscous fluid without using the torque of a motor that moves a squeegee.

Means for solving the problems

The screen printer disclosed in the present specification performs printing of a viscous fluid on a substrate using a mask on which a print pattern including through holes is formed.

The screen printer includes a contact member. In addition, the screen printing machine can move the contact member by the driving device to a contact position where the leading end of the contact member is in contact with the viscous fluid and a separation position where the leading end of the contact member is separated from the viscous fluid.

The screen printing machine further includes a measuring device that measures a length of the viscous fluid hanging down from the tip of the contact member when the contact member is moved from the contact position to the separation position by the driving device.

Further, the screen printer sets, by the control device, printing conditions for printing the viscous fluid on the substrate based on the measurement result of the measurement device.

By the viscosity of the viscous fluid, the viscous fluid adheres to the leading end of the contact member when the contact member is moved to the contact position. When the contact member is moved from the contact position to the separation position, the viscous fluid is suspended from the tip of the contact member by gravity. The length of the viscous fluid hanging down from the tip of the contact member (hereinafter referred to as a hanging-down length) varies depending on the viscosity of the viscous fluid. Specifically, when the viscosity is high, the sag length becomes short. When the viscosity is low, the sag length becomes long. Therefore, by measuring the hanging length of the viscous fluid, the viscosity of the viscous fluid can be measured without using the torque of the motor that moves the squeegee.

By setting the printing conditions using the measurement result, the printing conditions suitable for the viscosity of the viscous fluid that changes can be set.

In the screen printer disclosed in the present specification, the mask may have a surface to which the viscous fluid is supplied, and the contact member may be a squeegee for filling the through-holes of the mask with the viscous fluid.

Further, the screen printing machine may move the squeegee at a predetermined speed in a direction horizontal to the surface of the mask and at a predetermined speed in a direction perpendicular to the surface of the mask by the driving device while pressing the squeegee against the surface of the mask at a predetermined pressure at a predetermined angle with respect to the surface of the mask.

In this case, the contact position may be a position where the tip of the squeegee contacts the viscous fluid supplied to the surface of the mask, and the separation position may be a position where the viscous fluid supplied to the surface of the mask is separated from the viscous fluid hanging from the tip of the squeegee.

The screen printer prints a viscous fluid on a print target by moving a squeegee along a surface of a mask to which the viscous fluid is supplied. When the blade is brought into contact with the viscous fluid at the contact position and moved to the separation position, the viscous fluid is suspended.

According to this screen printer, the viscosity of the viscous fluid is measured by measuring the length of the viscous fluid hanging down from the squeegee. Since the squeegee used for printing is used, it is not necessary to separately provide a contact member only for measuring the viscosity of the viscous fluid.

The screen printing machine disclosed in the present specification may also use a measuring device to measure the length of the viscous fluid extending from the squeegee toward the mask when the squeegee is moved in a direction orthogonal to the surface of the mask after the squeegee fills the through holes of the mask with the viscous fluid.

In the screen printer, after the viscous fluid is moved by moving the squeegee in a certain direction, the squeegee is moved in a direction perpendicular to the surface of the mask in order to move the viscous fluid in the opposite direction. When the squeegee is moved in a direction perpendicular to the surface of the mask, the viscous fluid moves even if it adheres to the squeegee, and hangs down by gravity. By measuring the sag length, the viscosity of the viscous fluid can be measured.

Further, the measuring device in the screen printing machine disclosed in the present specification may measure a first length of the viscous fluid hanging down from the tip of the contact member when the contact member is moved from the contact position to the separation position at a first speed by the driving device, and may measure a second length of the viscous fluid hanging down from the tip of the contact member when the contact member is moved from the contact position to the separation position at a second speed different from the first speed by the driving device.

The control device may set the printing conditions for printing the viscous fluid on the substrate based on the first length and the second length measured by the measuring device.

According to this screen printing machine, the measurement variation in viscosity of the viscous fluid can be suppressed by measuring the sag length by changing the speed at which the contact member is moved.

The screen printing machine disclosed in the present specification may output a signal indicating occurrence of an abnormality based on a measurement result of the measuring device by the output device.

According to this screen printer, when the measured viscosity of the viscous fluid shows an abnormal value, an operator or the like can be made aware of the occurrence of the abnormality.

Details and further improvements of the technology disclosed in the present specification are described in the following "detailed description of the preferred embodiments".

Drawings

Fig. 1 is a side view in a housing showing the structure of a printer of the first embodiment.

Fig. 2 is a block diagram showing a configuration of control of the printing press of the first embodiment.

Fig. 3 is an enlarged view showing a portion III of fig. 1.

Fig. 4 is an enlarged view showing a state where solder droops.

Fig. 5 is a partial sectional view taken along line V-V of fig. 4.

Fig. 6 is a side view showing the operation of the squeegee according to the second embodiment.

Detailed Description

A screen printer 1 (hereinafter, referred to as a printer 1) of the first embodiment is explained with reference to the drawings. The printer 1 is a device that prints cream solder as a viscous fluid on a circuit board as a print target and conveys the printed cream solder to an electronic component mounting apparatus as a subsequent step. Further, the direction of the negative side of the Y axis in the drawing is expressed as the front side. The direction of the Y-axis positive side is expressed as the rear side, the direction of the Z-axis positive side is expressed as the upper side, and the direction of the Z-axis negative side is expressed as the lower side.

The structure of the printer 1 will be described with reference to fig. 1. Fig. 1 is a side view inside a housing 2 of a printing press 1. The printer 1 includes a squeegee unit 20, a squeegee drive device 4, a substrate transfer device 16, a substrate holding device 14, a solder supply device 40, a measurement device 50, a controller 90, and the like in a housing 2 which is a box-shaped casing. In addition, a monitor 92 is provided on the front side of the housing 2. The housing 2 is drawn in a perspective view in fig. 1, but in the embodiment, is formed of a 6-sided plate material, and partitions the inside of the printer 1.

As shown in fig. 1, a support base 12 is provided on the front side of the housing 2 of the printing press 1 at a substantially middle height. Similarly, a support base 12 is also provided on the rear side. The front support base 12 and the rear support base 12 are disposed at the same height. The mask 80 is configured to be mounted on 2 support tables 12. The front end and the rear end of the mask 80 are fixed to the mask support frame 18 from above. The mask 80 is a plate-shaped member having one or more pattern holes 80h corresponding to a print pattern. The pattern hole 80h penetrates the mask 80 in the Z-axis direction. The substrate 70 is disposed on the upper surface of the substrate holding device 14 so as to be in contact with the lower surface of the mask 80. The printer 1 prints solder on the substrate 70 through the pattern holes 80 h.

Further, a substrate transfer device 16 is provided below the substrate holding device 14. The substrate holding device 14 releases the substrate 70 after the printing is completed. The substrate transport device 16 transports the substrate 70 after printing in the direction of the X axis front side (the front side of the paper surface in fig. 1).

Next, the squeegee unit 20 included in the printer 1 will be described. The squeegee unit 20 includes: a front blade 24 provided on the front side of the unit main body 22 as a housing; and a scraper 26 provided on the rear side of the unit main body 22. The front blade 24 and the rear blade 26 penetrate from the upper surface to the lower surface of the unit body 22. The front blade 24 includes: a front-side angle adjusting device 28 that adjusts the angle of the front end of the front squeegee 24; and a front side elevating device 32 for moving the front side squeegee 24 in a direction orthogonal to the surface of the mask 80. Similarly, the rear blade 26 includes: a rear-side angle adjusting device 30 for adjusting the angle of the front end of the rear squeegee 26; and a rear lifting device 34 for moving the rear squeegee 26 in a direction orthogonal to the surface of the mask 80.

The squeegee unit 20 is moved in the front-rear direction (Y-axis direction) of the printing press 1 by the squeegee drive device 4. The squeegee drive device 4 includes a guide rail 10 extending in the front-rear direction of the printing press 1, a feed screw 8 extending parallel to the guide rail 10, and a servomotor 6. The guide rail 10 extends in a horizontal direction with respect to the surface of the mask 80, and supports the squeegee unit 20 to be slidable. The servomotor 6 is a motor for moving the squeegee unit 20, and is connected to the squeegee unit 20 via the feed screw 8. That is, the servomotor 6 rotates the feed screw 8 to move the squeegee unit 20 along the guide rail 10. The servo motor 6 may be a motor of another type capable of feedback control, such as a stepping motor.

As described above, the squeegee unit 20 moves the respective squeegees in the direction orthogonal to the surface of the mask 80 by the front side elevating device 32 and the rear side elevating device 34. For example, when the squeegee unit 20 is moved from the front side (Y-axis negative side) to the rear side (Y-axis positive side) to print solder on the substrate 70, the squeegee unit 20 first presses the front end of the front squeegee 24 against the surface of the mask 80. Then, the unused rear squeegee 26 is separated from the mask 80. At this time, the solder is supplied to the surface of the mask 80 at a position behind the front squeegee 24 and in front of the pattern holes 80 h. Then, the squeegee unit 20 presses the front end of the front squeegee 24 against the surface of the mask 80 by the squeegee drive device 4 and moves in the backward direction. By pressing the front end of the front-side squeegee 24 against the surface of the mask 80, the solder supplied onto the surface of the mask 80 is pressed by the front-side squeegee 24 to move to the rear side, and is filled in the pattern holes 80 h. The filled solder abuts the surface of the substrate 70 through the penetrating pattern hole 80 h. Thereby, solder is printed on the substrate 70.

In addition, when the solder is printed on the substrate 70, the squeegee unit 20 can adjust the pressing pressure of the front squeegee 24 against the mask 80 (hereinafter, referred to as printing pressure) by the front elevating device 32. In addition, the squeegee unit 20 can adjust the angle of the front squeegees 24 with respect to the surface of the mask 80 by the front-side angle adjustment device 28. Further, the printing press 1 adjusts the speed at which the squeegee unit 20 moves by the squeegee drive device 4, and as a result, the speed at which the squeegee 24 or 26 is moving in the printing direction during printing can be adjusted. By appropriately setting the printing conditions including these conditions according to the type, viscosity, and the like of the solder used for printing, it is possible to suppress the occurrence of printing defects such as solder shortage and solder leakage.

The printing press 1 has a controller 90 and a monitor 92. In fig. 1, to aid understanding, a controller 90 and a monitor 92 are shown above a side view of the printing press 1. Actually, the controller 90 and the monitor 92 are provided on the front surface (the surface on the left side of the paper surface in fig. 1) of the printer 1. The controller 90 controls each device of the printing press 1. The monitor 92 presents the setting state and the working state of the solder printer 1 to the operator, and receives various inputs from the operator via a switch or the like. The details of the control structure of the controller 90 will be described later.

Further, a solder supplying device 40 and a measuring device 50 are provided on the front side of the printer 1. The tray 46 is disposed below the measuring device 50, and the tray 46 is disposed on the upper surface of the front support base 12. The solder supplying device 40 and the measuring device 50 are connected via a measuring driving device 48. The solder supplying device 40 and the measuring device 50 are supported by the guide rail 10 via the measuring driving device 48 so as to be slidable in the front-rear direction of the printer 1. The solder supplying device 40 includes a solder container 42 and a solder ejecting portion 44. The solder supplying device 40 is also mounted slidably in the X-axis direction. The solder supplying device 40 supplies the solder 36 in the solder container 42 from the solder ejecting portion 44 to the surface of the tray 46 and the surface of the mask 80 while moving in the X-axis direction. Therefore, the solder 36 is supplied in a form extending in the X-axis direction.

The measurement device 50 includes a measurement device main body 52 connected to the measurement drive device 48, a measurement lifting device 54 extending downward from the measurement device main body 52, and a measurement device tip portion 56. The measuring device 50 has a laser measuring instrument 60 below the measuring device 50 and on the back side of the drawing, as will be described in detail later. The measuring device 50 measures the viscosity of the solder 36 supplied to the tray 46 by the solder supplying device 40 using the laser measuring device 60. The details of the method for measuring the viscosity will be described later.

As described above, the controller 90 controls the respective devices of the printing press 1. Fig. 2 shows a control configuration performed by the controller 90 of the printing press 1. The controller 90 has a Central Processing Unit (CPU) and is configured using a microprocessor operated by software. The controller 90 also has a volatile Random Access Memory (RAM), a nonvolatile Read Only Memory (ROM), a Hard Disk Drive (HDD), and an input/output interface. The controller 90 controls the respective portions of the printing press 1 using the input-output interface.

The controller 90 issues commands to the substrate transfer device 16 and the substrate holding device 14 to control the loading/unloading of the substrate 70 and the holding of the mask 80. The controller 90 controls the speed of raising and lowering each squeegee and the printing pressure by the front side raising and lowering device 32 and the rear side raising and lowering device 34 of the squeegee unit 20. The controller 90 controls the angle at which the leading end of each squeegee is pressed against the surface of the mask 80 by the front-side angle adjustment device 28 and the rear-side angle adjustment device 30 of the squeegee unit 20. The controller 90 controls the speed of movement and the direction of movement of the squeegee unit 20 by the squeegee drive device 4. The controller 90 sends an instruction to the solder supplying apparatus 40 to supply solder to the surface of the tray 46 and the mask 80. That is, the controller 90 sets the printing conditions of the printing press 1.

Further, the controller 90 receives the measurement result of the viscosity of the solder 36 from the measurement device 50. The controller 90 transmits, to each device, a printing pressure, an angle of the blade tip, a speed of raising and lowering each blade, a speed of moving the blade in printing in the printing direction, and the like in accordance with the received viscosity measurement result. That is, the printing conditions are set using the viscosity measurement results. This makes it possible to set printing conditions suitable for a changing viscosity of the viscous fluid.

Here, the operation of the measuring device 50 will be described with reference to fig. 3 to 4. FIGS. 3 to 4 are enlarged views of the range III surrounded by the two-dot chain line in FIG. 1. First, the solder supplying device 40 supplies the solder 36a to the surface of the tray 46 while moving in the X-axis direction. Therefore, the solder 36a extends in the X-axis direction. Thereafter, the measuring device 50 is moved upward of the solder 36a by the measuring drive device 48. Here, the measurement tip 56 disposed at the tip of the measurement device 50 is also a plate-like member extending in the X-axis direction. The measurement tip portion 56 has the same shape as the tip of the front blade 24. The measurement tip portion 56 is made of the same polyurethane as the tip of the front blade 24 and the tip of the rear blade 26.

Thereafter, the measurement lifting and lowering device 54 moves the measurement tip portion 56 in the direction of the tray 46. Thereby, as shown in fig. 3, the measurement tip portion 56 is brought into contact with the solder 36 a. When the measurement tip portion 56 is in contact with the solder 36a, the solder 36b as a part of the solder 36a adheres to the measurement tip portion 56.

Next, as shown in fig. 4, the measurement lifting and lowering device 54 moves the measurement tip portion 56 upward. As described above, the solder 36b is attached to the measurement tip portion 56. Therefore, when the measurement tip portion 56 moves upward, the solder 36b attached to the measurement tip portion 56 also moves upward together as shown in fig. 4. When the solder 36b moves upward, the solder 36a remaining on the tray 46 is separated from the solder 36b attached to the measurement tip portion 56. That is, the measurement tip 56 is separated from the solder 36a in contact. At this time, the solder 36b attached to the measurement tip portion 56 hangs down from the measurement tip portion 56 due to gravity.

A method of measuring the viscosity of the solder 36 will be described with reference to fig. 5. Fig. 5 is a partial cross-sectional view of the measuring device 50 and the solders 36a and 36b in V-V of fig. 4. As described above, the solder 36a extends in the X-axis direction. The amount and viscosity of the solder 36a in the X-axis direction are not constant. Therefore, the amount and viscosity of the solder 36b attached to the measurement tip portion 56 are not constant in the X-axis direction. That is, the hanging length of the solder 36b is not constant in the X-axis direction. The laser measuring instrument 60 measures the distance between the lower end of the tip end portion 56 and the lowest point of the solder 36b as the hanging length. Further, if the position (height) of the lower end of the measurement tip portion 56 is known in advance from the position at which the measurement elevating device 54 is stopped, the hanging-down length can be measured by measuring the position of the lowermost end of the solder 36 b.

The hanging length of the solder 36b has a correlation with the viscosity of the solder 36 b. Specifically, if the hanging length is long, the viscosity of the solder 36b is low. Conversely, if the hanging length is short, the viscosity of solder 36b is high. Therefore, the measuring device 50 can measure the viscosity of the solder 36b by measuring the hanging length. That is, the printer 1 can measure the viscosity of the solder 36b without using the torque of the motor that moves the squeegee.

The laser measuring device 60 sends the measured sag length to the controller 90. As described above, the controller 90 sets the printing conditions suitable for the viscosity of the solder 36b based on the received sag length. The controller 90 transmits the set printing conditions to the respective apparatuses. That is, the printer 1 can set printing conditions suitable for the viscosity of the solder 36b using the measurement result.

Next, a method of measuring viscosity in the printer 1a according to the second embodiment will be described with reference to fig. 6. Fig. 6 is an enlarged side view showing the operation of the squeegee unit 20 during printing. In fig. 6, the housing 2, the support base 12, the substrate transfer device 16, and the like in fig. 1 are not illustrated for easy understanding of the drawings. In the printer 1a of the second embodiment, the solder supplying device supplies the solder 36d to the surface of the mask 80. As described above, the front squeegee 24 is moved by the front lifter 32 in the direction of the surface of the mask 80. Thereby, the front end of the front-side squeegee 24 is brought into contact with the solder 36 d. When the front end of the front-side squeegee 24 is in contact with the solder 36d, a part of the solder 36d adheres to the front end of the front-side squeegee 24. Thereafter, the front side elevating device 32 moves the front side squeegee 24 in the direction of an arrow US1 at a speed of, for example, 50 mm/s. Here, as shown in fig. 6, the direction of the arrow US1 is orthogonal to the surface of the mask 80. As described above, a part of the solder 36d is attached to the front end of the front squeegee 24. Therefore, when the front side squeegee 24 moves in the direction of the arrow US1, the solder 36d attached to the front end of the front side squeegee 24 also moves together as shown in fig. 4. At this time, the attached solder 36d hangs down from the front end of the front squeegee 24 by gravity. Although not shown in fig. 6, a laser measurement device is also provided on the back side of the front blade 24 of the blade unit 20 of the printing press 1 a. As shown in fig. 5, in the printer 1a of the second embodiment, the viscosity of the solder 36d can also be measured by measuring the length of the attached solder 36d hanging from the tip of the front squeegee 24 using a laser measuring instrument. That is, the printer 1a can measure the viscosity of the solder 36d without using the torque of the motor that moves the squeegee.

As in the first embodiment, the laser measuring device transmits the measured sag length to the controller 90. As described above, the controller 90 sets the printing condition suitable for the viscosity of the solder 36d based on the received sag length. The controller 90 transmits the set printing conditions to the respective apparatuses. That is, the printer 1a can set printing conditions suitable for the viscosity of the solder 36d using the measurement results. In the printer 1a of the second embodiment, the blade driving device 4 for moving the blade unit 20 in the printing direction and the elevating devices 32 and 34 for elevating the blades 24 and 26 constitute an example of the driving device described in the claims.

The front squeegee 24 of the printer 1a according to the second embodiment is moved by the squeegee drive device 4 at a predetermined speed in the direction RS1 horizontal to the surface of the mask 80 while being pressed against the surface of the mask 80 at a predetermined pressure and at a predetermined angle with respect to the surface of the mask 80. In other words, the front squeegee 24 moves in the direction of arrow RS1 in fig. 6 while filling the pattern holes 80h of the mask 80 with the solder 36. That is, the printer 1a prints the solder 36 on the substrate 70 using the front squeegee 24.

Therefore, by using the printer 1a of the second embodiment, the viscosity of the solder can be measured using a squeegee necessary for printing. That is, since the squeegee used for printing is used, it is not necessary to separately provide a contact member only for measuring the viscosity of the solder.

The printer 1a can also measure the viscosity of the solder 36e at the position of the squeegee unit 20a shown in fig. 6. The squeegee unit 20a shows a state of the squeegee unit 20 after the front-side squeegees 24 fill the solder 36 into the pattern holes 80h of the mask 80. The solder 36d before printing is reduced in amount by filling the pattern holes 80h of the mask 80, and the remaining solder 36e is in contact with the front squeegee 24. Therefore, a part of the solder 36e adheres to the front end of the front-side squeegee 24. Thereafter, the front lifter 32 moves the front squeegee 24 in the direction of the arrow US 2. The direction of the arrow US2 is orthogonal to the surface of the mask 80. A part of the solder 36e is attached to the front end of the front squeegee 24. Therefore, when the front side squeegee 24 moves in the direction of the arrow US2, the solder 36e attached to the front end of the front side squeegee 24 also moves together, similarly to the solder 36b shown in fig. 4. At this time, the attached solder 36e hangs down from the front end of the front squeegee 24 by gravity. Although not shown in fig. 6, a laser measurement device is also provided on the back side of the front blade 24 of the blade unit 20a of the printer 1 a. Similarly to the solder 36b shown in fig. 5, in the printer 1a of the second embodiment, the length of the solder 36e attached to the front end of the front squeegee 24 is measured by a laser measuring instrument, whereby the viscosity of the solder 36e can be measured. That is, the printer 1a can measure the viscosity of the solder 36e without using the torque of the motor that moves the squeegee. During this time, the substrate transfer device 16 transfers the substrate 70 to the subsequent process, and a new substrate is disposed on the upper surface of the substrate holding device 14.

Thereafter, while the front squeegee 24 is moving in the direction of arrow US2, the squeegee unit 20a moves the rear squeegee 26 in the direction of arrow US3 using the rear lift device 34. The squeegee unit 20a moves at a predetermined speed in a direction RS2 horizontal to the surface of the mask 80 while pressing the front end of the rear squeegee 26 against the surface of the mask 80 at a predetermined pressure and at a predetermined angle with respect to the surface of the mask 80. That is, the squeegee unit 20a prints the solder 36 on the new substrate 70. Thereafter, this time, the rear squeegee 26 is moved in a direction away from the mask 80. At this time, the viscosity of the solder 36 remaining on the surface of the mask 80 is measured. When the viscosity of the solder 36 is measured, the front squeegee 24 is moved in a direction approaching the surface of the mask 80. During this period, the substrate transfer device 16 transfers the substrate 70 to the subsequent process, and a new substrate is disposed on the upper surface of the substrate holding device 14. Hereinafter, measurement of the viscosity of the solder and printing of the solder on the substrate are alternately repeated.

As described above, in the printer 1a, in order to change the moving direction of the squeegee unit 20, the front and rear squeegees are moved up and down for each printing operation, and the replacement is performed. That is, by measuring the length of the hanging down from the tip of the squeegee at the time of the raising and lowering, the viscosity of the solder during printing by the printer 1a can be measured without using the torque of the motor that moves the squeegee. The viscosity of the solder generally has a tendency to rise over time. In other words, the viscosity of the solder changes during printing. That is, the viscosity of the solder can be measured by the operation of replacing the squeegee before and after the operation, and the viscosity of the solder that changes during printing can be measured. The controller 90 controls each device using the measurement result. Therefore, the controller 90 can set the printing conditions suitable for the viscosity of the solder that changes during printing. The measurement of the viscosity may be performed at each time of changing the front and rear squeegees, but the measurement frequency may be changed. For example, the viscosity may be measured by replacing the squeegee twice in accordance with the conveyance of the substrate 70.

In the above-described embodiment, the speed at which the measuring tip portion 56 and the squeegee are moved can be changed when the hanging length of the solder 36 is measured. Specifically, for example, the solder 36 is attached to the measurement tip portion 56 of the printer 1 of the first embodiment shown in fig. 3 to 4, the hanging length is measured with the speed of moving the measurement tip portion 56 upward being 100mm/s, and then the hanging length is measured with the speed of moving the measurement tip portion 56 upward being changed to 50 mm/s. When the speed at which the measurement tip portion 56 is moved upward is changed, the hanging length is also changed. The deformation of the viscous fluid depends on the speed, and even if the same load is applied, the deformation amount is small when the speed is high, and the deformation amount is large when the speed is low. By measuring the sagging length at different speeds, measurement variation in viscosity of the solder can be suppressed.

The measurement device 50 transmits the sag lengths measured by the different speed meters to the controller 90. The controller 90 estimates the viscosity from the received different sag lengths, and sets printing conditions appropriate for the estimated viscosity. For example, the viscosity of the solder may be estimated using the difference between a first sag length when the squeegee is moved at a first speed (e.g., 100mm/s) and a second sag length when the squeegee is moved at a second speed (e.g., 50 mm/s). Alternatively, a control map for determining the printing conditions using the first hanging length and the second hanging length as parameters may be created in advance, and the printing conditions may be set using the measurement values and the control map. The measurement of the sag length at different speeds is not limited to 2 speeds, and the printing conditions may be set using the sag lengths measured by 3 or more different speeds.

Further, when the viscosity of the solder 36 sent from the measuring device 50 exceeds a predetermined threshold value, the controller 90 can send a command to the warning device 62 and output a signal indicating the occurrence of an abnormality to the monitor 92. Thus, when the viscosity of the viscous fluid measured by the measuring device 50 indicates an abnormal value, an operator or the like can be made aware of the occurrence of the abnormality. The threshold value differs depending on the type of solder used for printing, the surrounding environmental conditions, and the like.

The mask 80 of the printer 1 of the present embodiment is a metal mask formed of a metal material. However, in the technique disclosed in the present specification, the specific material and structure of the mask 80 are not particularly limited. Further, as described above, the measurement tip portion 56 and the tips of the blades are formed of polyurethane, but the technique disclosed in the present specification can be applied to metal blades made of other materials, for example, stainless steel.

Further, the squeegee unit 20 of the printing press 1 of the present embodiment includes two squeegees 24 and 26 corresponding to the moving direction, but the squeegee unit 20 may include one or three or more squeegees as another embodiment. In the printer 1 of the present embodiment, the solder is supplied to the surface of the tray 46 and the mask 80 by the solder supplying device 40. The solder supplying device 40 is not an essential component, and a worker may manually supply solder to the surface of the tray 46 or the mask 80.

In the printers 1 and 1a of the present embodiment, the solder sag length is measured by the laser measuring device, but the method of measuring the solder sag length is not limited to the laser measuring device, and another measuring device may be used.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the claims. The techniques recited in the claims include various modifications and changes made to the specific examples illustrated above. The technical elements described in the specification and drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in the present specification or the drawings can achieve a plurality of objects at the same time, and achieving one of the objects has technical usefulness.

Description of the reference numerals

1. 1 a: printing machine

2: outer casing

4: scraper driving device

6: servo motor

8: feed screw

10: guide rail

12: supporting table

14: substrate holding device

16: substrate conveying device

18: mask support frame

20. 20 a: scraper unit

22: unit body

24: front side scraper

26: rear side scraper

28: front side angle adjusting device

30: rear side angle adjusting device

32: front side lifting device

34: rear lifting device

36. 36a to e: solder

40: solder supplying device

42: solder container

44: solder ejection part

46: tray

48: measurement drive device

50: measuring device

52: measuring device main body

54: measuring and lifting device

56: measurement tip

60: laser measuring device

62: warning device

70: substrate

80: mask and method for manufacturing the same

80 h: pattern hole

90: controller

92: monitor with a display