JPH1044370A - Screen printer and its controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen printer and its controlling method for correcting misalignment between a substrate and a screen with high accuracy. SOLUTION: The screen printer comprises a substrate support table 2 movable in X-axis and Y-axis directions and rotating in a horizontal plane, a screen support means 3 disposed above the table 2 and movable in the Y-axis direction, a first imaging means 4 disposed between the table 2 and the means 3, movable in the X-axis and Y-axis directions to image a substrate P, a second imaging means 5 disposed above the means 3, movable in the X-axis and Y-axis directions to image a screen S, and a control means for allowing the means 4 to image the substrate before printing is conducted on the substrate to recognize a position of the substrate, for allowing the means 5 to image the screen to recognize a position of the screen to calculate the misalignment between the substrate and the screen, and driving the table 2 and the means 3 to correct the misalignment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printer for printing a paste such as a cream solder for soldering an electronic component on a substrate, and a control method therefor.

[0002]

2. Description of the Related Art As is well known, a screen printing machine is used to print a paste such as cream solder on a substrate. Conventional screen printing machines include a moving mechanism for moving in the X-axis and Y-axis directions extending in the horizontal direction, a moving mechanism for moving in the Z-axis direction extending in the vertical direction, and rotation for rotating in a horizontal plane. A substrate supporting table having a mechanism, screen supporting means disposed above the substrate supporting table, and disposed between the substrate supporting table and the screen supporting means, the substrate supporting table being movable in the X-axis and Y-axis directions; There is provided imaging means having a camera for imaging the substrate placed on the support table and the screen supported by the screen support means.

In order to perform screen printing on a substrate by using this screen printing machine, first, an imaging means is used to image the substrate before screen printing placed on the substrate support table and the screen supported by the screen support means. Recognizes the position of the substrate and the screen, calculates the displacement between the substrate and the screen from the obtained position information of the substrate and the screen, moves the substrate support table in the X-axis and Y-axis directions, and rotates in the horizontal plane. To correct the deviation. Then, the imaging unit is retracted in the horizontal direction, the substrate support table is raised, the substrate is pressed against the lower surface of the screen, and the squeegee is moved along the upper surface of the screen to print the paste on the substrate.

[0004]

The conventional screen printing machine cannot calculate the displacement between the substrate and the screen when the substrate is at a position in contact with the screen. If the mechanism for moving the screen is distorted, there is a problem that printing is performed in a state where the substrate and the screen are displaced.

In a conventional screen printing machine, a single camera captures an image of a substrate and a screen. Images of the substrate and the screen are captured by a camera through a complicated optical system. There is a problem that distortion is easily generated in the system and it is difficult to accurately recognize the position of the substrate and the screen.

Further, since the optical system for capturing the image on the screen is arranged with the incident surface of the image facing the lower surface of the screen, the paste dropped from the screen adheres to the incident surface of the optical system, and the camera is moved to the screen. There is a problem that the exact position of the camera cannot be recognized.

An object of the present invention is to solve the above problems and to provide a screen printer capable of correcting a displacement between a substrate and a screen with high accuracy, and a control method thereof. is there.

Another object of the present invention is to provide a screen printing machine capable of manufacturing a substrate having a high-quality printing paste with little chipping or blurring.

[0009]

In order to achieve the above-mentioned object, the invention of claim 1 comprises a first moving mechanism for moving in the direction of the X-axis extending in the horizontal direction and a moving mechanism of the Z-axis extending in the vertical direction. A substrate supporting table having a second moving mechanism for moving in a horizontal direction and a rotating mechanism for rotating in a horizontal plane; and a moving unit for moving in a direction of a Y-axis extending in a horizontal direction and disposed above the substrate supporting table. A screen supporting means having a moving mechanism, disposed between the substrate supporting table and the screen supporting means, movable in the directions of the X axis and the Y axis, and imaging the substrate placed on the substrate supporting table; A first imaging unit having a camera that moves the camera, and a camera disposed above the screen supporting unit and movable in the X-axis and the Y-axis directions to image the screen supported by the screen supporting unit. Before performing screen printing on the substrate, causing the first imaging unit to image the substrate to recognize the position of the substrate, and causing the second imaging unit to image the screen. The position of the screen is recognized, a displacement between the substrate and the screen is calculated from the obtained position information of the substrate and the screen, and a first movement mechanism and a rotation mechanism of the substrate support table, the screen support Control means for driving the moving mechanism of the means to correct the displacement.

According to a second aspect of the present invention, in the screen printing machine according to the first aspect, there is provided a printing paste quality determining unit for determining at least a positional shift of the printing paste from an image of the board after screen printing captured by the first imaging unit. Wherein the control means corrects the displacement between the substrate and the screen based on the print paste positional deviation information from the print paste quality determining means.

According to a third aspect of the present invention, in the screen printing machine according to the second aspect, the control means periodically causes the first imaging means to image the substrate after screen printing, and obtains the print paste from the obtained image. It is characterized in that the quality determining means determines the quality of the printed paste on the substrate.

According to a fourth aspect of the present invention, in the screen printing machine according to any one of the first to third aspects, the clogging of the opening of the screen is determined from the image of the screen captured by the second imaging means. It is characterized in that clogging determining means is provided.

According to a fifth aspect of the present invention, in the screen printing machine according to the fourth aspect, the control means causes the second imaging means to periodically take an image of the screen, and causes the clogging determination means to perform the clogging determination based on the obtained image. The clogging of the opening of the screen is determined.

According to a sixth aspect of the present invention, there is provided the screen printing machine according to any one of the first to fifth aspects, wherein the gas is disposed above or below the screen, is movable vertically, and blows gas to the screen. A cleaning unit provided with a spraying unit and a suction unit that is disposed to face the gas blowing unit with the screen interposed therebetween and that is vertically movable and sucks a residue of the printing paste attached to the screen. It is characterized by having.

According to a seventh aspect of the present invention, in the screen printing machine according to the sixth aspect, the cleaning means is disposed between the screen and the suction means, comes into contact with and separates from the screen, and the residue of the printing paste. A cleaning sheet having air permeability for adhering to the cleaning sheet.

According to an eighth aspect of the present invention, there is provided the screen printing machine according to any one of the first to seventh aspects, wherein the residue of the printing paste attached to the screen is vertically movable below the screen. Suction means, which is disposed between the screen and the suction means, comes into contact with and separates from the screen, and is movable in the vertical direction,
A cleaning means including a cleaning sheet having air permeability for adhering the residue of the printing paste is provided, and the squeegee for applying the printing paste relatively moves on the screen so that the screen is pressed against the cleaning sheet. It is characterized by having made it.

According to a ninth aspect of the present invention, in the screen printing machine according to any one of the sixth to eighth aspects, the control means determines whether or not the determination result of the print paste good / bad determination means or the clogging determination means is negative. In this case, the screen is cleaned by the cleaning means.

The invention according to claim 10 is the invention according to claims 1 to 9
The method of controlling a screen printing machine according to any one of claims 1 to 3, wherein the substrate placed on the substrate support table is moved to the first position.
Causing the imaging means to take an image, raising the substrate support table to a printing position, and causing the second imaging means to image the substrate,
A difference between the position information of the substrate obtained by the first image pickup means and the position information of the substrate obtained by the second image pickup means is calculated, and the substrate and the substrate are moved so that an error due to the deviation is eliminated. It is characterized in that a deviation from the screen is corrected.

According to an eleventh aspect of the present invention, in the method for controlling a screen printing machine according to the tenth aspect, the calibration jig plate having a calibration mark on a surface and having a known position of the calibration mark is supported on the substrate support. The calibration mark is placed on a table, and the calibration mark is imaged by the first and second imaging means. The position information of the calibration mark obtained by the first and second imaging means and the known information of the calibration mark are obtained. Is calculated, and the position of the substrate and the screen is recognized so as to eliminate the error due to the deviation.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a main part of a screen printing machine according to a first embodiment of the present invention, and FIG.
FIG. 3 is a right side view of the screen printing machine of FIG. 1, and FIG. 4 is a block diagram of a control circuit of the screen printing machine of FIG.

The screen printing machine shown in FIG. 1 is for printing cream solder on a substrate, and is provided with a substrate supporting table 2 installed on a base 1 and above the substrate supporting table 2. A first screen supporting means, disposed between the substrate supporting table and the screen supporting means, for capturing an image of a substrate mounted on the substrate supporting table;
It is arranged above the imaging means 4 and the screen support means 3,
A second imaging means 5 for imaging the screen S supported by the screen support means 3, a print head 6 arranged above the screen S, a supply conveyor 7 for supplying the substrate P onto the substrate support table 1, and a substrate A discharge conveyor 8 for discharging P from the substrate support table 1, a substrate support table 2,
A control unit 9 (see FIG. 4) for driving and controlling the screen support unit 3, the first imaging unit 4, the second imaging unit 5, the print head 6, the supply conveyor 7, and the discharge conveyor 8 is provided.

The substrate support table 2 is provided with a first moving mechanism 10 for moving in the direction of the X-axis extending in the horizontal direction (the left-right direction in FIG. 1), and is provided on the first moving mechanism 10 so as to be positioned in a horizontal plane. A rotating mechanism 11 for rotating, a second moving mechanism 12 provided on the rotating mechanism 11 for moving in a Z-axis direction extending in a vertical direction, and a second moving mechanism 12
The apparatus includes a substrate support plate 13 provided thereon, and a transfer mechanism (not shown) provided on the upper surface of the substrate support plate 13 for transferring the substrate P in the X-axis direction. The substrate P
Are provided with two position recognition marks (not shown).

The screen support means 3 includes a screen support frame 14 for supporting the lower surface of the peripheral portion of the screen S, and a plurality of screen support means 3 disposed above the screen support frame 14 for pressing the peripheral portion of the screen S against the screen support frame 14. And a moving mechanism 16 for moving in the direction of the Y axis extending in the horizontal direction (see FIG. 2). It should be noted that two position recognition marks (not shown) are provided on the upper surface of the screen S.

The first imaging means 4 includes a camera 17 and a moving mechanism 18 for moving the camera 17 in the X-axis direction and the Y-axis direction.
And Further, the second imaging unit 5 includes a camera 19
And a moving mechanism 20 for moving the camera 19 in the X-axis direction. The camera 19 is supported movably in the Y-axis direction by a moving mechanism 22 (described later) of the print head 6.

The print head 6 has a squeegee 21 for applying a printing paste provided at a lower portion, a moving mechanism 22 for moving in the Y-axis direction, and a vertical moving mechanism 23 for moving the squeegee 21 in the Z-axis direction. And

The supply conveyor 7 moves the substrate support table 2 in the X-axis direction so that the substrate support table 2
When the supply conveyor 7 is driven in this state, the transport mechanism of the substrate support table 2 is interlocked.

The discharge conveyor 8 moves the substrate support table 2 in the X-axis direction so that the substrate support table 2 is moved.
When the discharge conveyor 8 is driven in this state, the transport mechanism of the substrate support table 2 is interlocked.

As shown in FIG. 4, the control means 9 includes a recognition board 24, a CPU 25 for performing overall control according to a program stored in a ROM (not shown), and a motor control unit 26. The board 24 is connected to a CPU 25 and a motor control unit 26 via a bus 27.
The camera 17 of the first imaging unit 4 and the camera 19 of the second imaging unit 5 are connected to the recognition board 24. The motor control unit 26 is connected to the substrate support table 2 via a servo motor driver SMD or a pulse motor driver PMD.
The first and second moving mechanisms 10 and 12, the rotating mechanism 11, the moving mechanism 16 of the screen supporting means 3, the moving mechanism 18 of the first imaging means 4, the moving mechanism 20 of the second imaging means 5, and the movement of the print head 6. The servo motor SM or the pulse motor PM of the mechanism 22 is connected.

SM1 is a servo motor of the second moving mechanism 12 of the substrate support table 2, PM1 is a pulse motor of the rotating mechanism 11, PM2 is a pulse motor of the first moving mechanism 10, P
M3 is a pulse motor of the moving mechanism 16 of the screen support means 3, PM4 is an X-axis pulse motor of the moving mechanism 18 of the first imaging means 4, PM5 is a Y-axis pulse motor of the moving mechanism 18, and SM2 is a second imaging means. Reference numeral 5 denotes a servo motor of the moving mechanism 20, and reference numeral PM6 denotes a pulse motor of the moving mechanism 22 that moves the camera 19 of the second imaging means 5 in the Y axis direction.

In FIG. 3, reference numeral 28 denotes a housing,
Numerals 29 and 30 denote gull-wing type doors for opening and closing openings (not shown) provided on the front and rear surfaces of the housing 28.

Next, the operation of the screen printing apparatus configured as described above will be described. First, before performing screen printing on the substrate P, the camera 17 of the first imaging unit 4 and the camera 19 of the second imaging unit 5 are aligned.

When the substrate P is placed on the supply conveyor 7,
A photo sensor (not shown) detects this, and a substrate stopper (not shown) is lowered to hold the substrate P so as not to move during transportation. Next, the substrate support table 2 moves to the left and is connected to the supply conveyor 7. The supply conveyor 7 is driven, and the substrate P is conveyed toward the substrate support table 2 in conjunction with the conveyance mechanism of the substrate support table 2.
When the substrate P reaches a predetermined position on the substrate support table 2,
The supply conveyor 7 stops. Then, after the substrate P is positioned by a known positioning mechanism (not shown), the substrate support table 2 moves rightward and returns to the original position (hereinafter, referred to as the origin position).

Next, the camera 17 of the first image pickup means 4 moves in the X-axis direction and the Y-axis direction to pick up two position recognition marks on the substrate P. The image is stored on the recognition board 24. The CPU 25 recognizes the position of each position recognition mark from the image stored in the recognition board 24 and stores the position in the RAM (not shown).

Next, the camera 17 and the screen supporting means 3 are retracted in the horizontal direction, and the substrate supporting table 2 is raised.
When the substrate P reaches the printing position, the substrate support table 2 stops. The camera 19 of the second imaging means 5 moves in the X-axis direction and the Y-axis direction to capture two position recognition marks on the substrate P, and the images are stored in the recognition board 24. CPU
A RAM 25 recognizes the position of each position recognition mark from the image stored in the recognition board 24, and stores the obtained position information in a RAM.
Is compared with the position information obtained by the first image pickup means 4 stored in the first section. This displacement is caused by the displacement between the camera 17 and the camera 19 and the substrate support table 2.
Is caused by the distortion of the second moving mechanism 12 for moving in the Z-axis direction. The CPU 25 calculates the amount of movement of the camera 19 to eliminate the deviation, moves the camera 19, and stores the position in the RAM as a new reference position of the camera 19. Then, the substrate support table 2 moves down to the origin position, the screen support means 3 returns to the printing position, and the camera 17 returns to the reference position.

Next, a case where screen printing is actually performed on the substrate P will be described. First, the camera 17 of the first imaging means 4 moves in the X-axis direction and the Y-axis direction to capture two position recognition marks on the substrate P, and the images are stored in the recognition board 24. Then, the CPU 25 sets the recognition board 2
The position of each position recognition mark is recognized from the image stored in No. 4, and the position information is stored in the RAM. The camera 19 of the second imaging means 5 moves in the X-axis direction and the Y-axis direction to capture two position recognition marks on the screen S, and the images are stored in the recognition board 24. And CPU
25 recognizes the position of each position recognition mark from the image stored in the recognition board 24, compares the obtained position information with the position information of the position recognition mark of the substrate P stored in the RAM, and The deviation from the screen S is calculated.

The CPU 25 calculates the amount of movement of the substrate support table 2 and the screen support means 3 for correcting this displacement, and based on the obtained values, the motor control unit 26 causes the moving mechanism 10 of the substrate support table 2 to The motor of the rotating mechanism 11 and the moving mechanism 16 of the screen supporting means 3 is driven to correct the displacement between the substrate P and the screen S.

Next, the cameras 17 and 19 of the first and second imaging means 4 and 5 are retracted, and the substrate support table 2 is raised.
When the substrate P reaches the printing position, it stops. Then, the print head 6 is lowered, the squeegee 21 slides along the upper surface of the screen S, and the cream solder is printed on the substrate P. When printing is completed, the substrate support table 2 is lowered,
When it reaches the home position, it temporarily stops, moves rightward, and is connected to the discharge conveyor 8. Then, the positioning mechanism for positioning the substrate P is released, the discharge conveyor 8 is driven, and the transfer mechanism of the substrate support table 2 is interlocked with the discharge conveyor 8 to transfer the substrate P toward the discharge conveyor 8. Substrate P
Reaches a predetermined position on the discharge conveyor 8, the discharge conveyor 8 stops. Then, the substrate support table 2 returns to the origin position.

Thereafter, the discharge conveyor 8 is driven, and the substrate P is transported to a chip mounter (not shown). After the electronic components are attached, the substrate P is transported into a furnace, where the electronic components are soldered. On the other hand, the substrate support table 2 is connected to the supply conveyor 7 and receives the next substrate P from the supply conveyor 7. Then, the above steps are repeated, and screen printing is performed on the substrate P.

In the above embodiment, the cameras 17, 1
9 and the second moving mechanism 12 of the substrate support table 2.
Camera 1
Although the reference position of No. 9 is changed, the reference position of the camera 17 may be changed instead. Instead of changing the reference position of the camera, an offset value to be added to the movement amount of the substrate support table 2 and / or the screen support means 3 to correct the displacement is calculated, and this offset value is calculated. And / or may be added to the amount of movement of the screen support means 3. The alignment between the camera 17 and the camera 19 and the calculation of the offset value need not be performed for all the substrates, but may be performed at predetermined intervals (such as the number of printed substrates and the elapsed time).

Next, a second embodiment of the present invention will be described. In this embodiment, using a calibration jig plate (not shown) having a calibration mark on the surface, the position recognition deviation caused by the distortion of the moving mechanism 18 of the camera 17 of the first imaging means 4 and the second The displacement of the position recognition caused by the distortion of the moving mechanism 20, 22 of the camera 19 of the imaging means 5 is calculated, and the position recognition of the substrate P and the screen S is performed so that the error due to these displacements is eliminated.

The calibration jig plate has, on its surface, a calibration mark composed of a plurality of lines provided in a grid pattern, and the positions of these lines from the reference point are precisely determined by a measuring instrument. The measured value is stored in the RAM of the control means 9.

Next, the calibration jig plate is placed on the supply conveyor 7. The calibration jig plate is positioned on the substrate support table 2 according to the same process as in the first embodiment. Then, the camera 17 of the first imaging unit 4 moves in the X-axis direction and the Y-axis direction to sequentially image the lines of the calibration mark,
The image is stored on the recognition board 24. CPU25
Calculates the position of each line of the calibration mark from the reference point from the image stored in the recognition board 24, compares the calculated position with the position information of each line of the calibration mark previously stored in the RAM, and Calculate the deviation. This displacement is caused by the distortion of the mechanism 18 for moving the camera 17. The CPU 25 calculates an offset value to be added to the movement amount of the camera 17 to correct this deviation,
Store in AM.

Next, the camera 17 and the screen supporting means 3
Is retracted, the substrate support table 2 moves up, and stops when the calibration jig plate reaches the printing position. Then, the camera 19 of the second imaging means 5 moves in the X-axis direction and the Y-axis direction to sequentially capture the lines of the calibration mark, and the images are recognized by the recognition board 24.
To memorize. The CPU 25 calculates the position of each line of the calibration mark from the reference point from the image stored in the recognition board 24, compares the calculated position with the position information of each line of the calibration mark stored in the RAM in advance, and compares them. Is calculated. This displacement is caused by the mechanism 20 for moving the camera 19,
22. CPU25
Calculates an offset value to be added to the movement amount of the camera 19 in order to correct this shift, and stores the calculated offset value in the RAM. Then, the substrate support table 2 is lowered to the origin position, and the calibration jig plate is discharged by the discharge conveyor 8.

When performing screen printing on the substrate P, first, as in the first embodiment, the camera 17
And the camera 19 images the position recognition mark on the screen S. Then, the offset value is added to the obtained position information of the substrate P and the screen S, and the position of the substrate P and the screen S is recognized. In this way, more accurate position recognition between the substrate P and the screen S can be performed, and the displacement between the substrate P and the screen S can be corrected with higher accuracy.

Next, a third embodiment of the present invention will be described. In this embodiment, the control unit 9 determines whether the printing paste of the printing paste is misaligned, frayed, thinned, bridged, bleeding, or the like from the image of the substrate P after screen printing captured by the camera 17 of the first imaging unit 4. A determination means is provided. This print paste quality determination means is a ROM
The printed paste quality determining means periodically determines the quality of the cream solder on the substrate P. Note that the cycle is determined by, for example, the number of printed boards, elapsed time, and the like.

The procedure for determining the quality of the print paste by the print paste quality determining means will be described with reference to the flowcharts of FIGS. Information such as the area, shape, and position of the cream solder print area on the substrate P is stored in the RAM in advance, and an inspection range is set for each cream solder print area based on the information (step #).
5).

Next, the image in the inspection range captured by the camera 17 is binarized (step # 10), and the shape of the cream solder printing area is compared with the shape of the cream solder printing area stored in the RAM in advance. Then, the center of the cream solder print area is calculated (step # 15). By comparing this center position with the center position of the cream solder printing area stored in the RAM, a shift of the cream solder printing area is calculated (step # 20), and whether or not this shift is equal to or less than an allowable value is determined. Is determined (step # 25), and if it is larger than the allowable value, N
G is determined (step # 30), a display indicating NG is made on a display (not shown), and the process is interrupted. Then, based on the obtained print misalignment information, the motor control unit 2
6 drives the motors of the first moving mechanism 10 of the substrate supporting table 2, the rotating mechanism 11, and the moving mechanism 16 of the screen supporting means 3 to correct the displacement between the substrate P and the screen S.

If the deviation is equal to or less than the allowable value, the process proceeds to a step of determining whether or not the lack or thinness of the cream solder is equal to or less than the allowable value. First, the area of the cream solder area is measured by counting the number of pixels of the cream solder print area (step # 35), and the absolute value of the difference between the measured area and the reference area stored in the RAM is equal to or less than the allowable value. Is determined (step # 40), and if the area difference is larger than the allowable value, it is determined that the area is NG (step # 45), a display indicating NG is made on the display, and the process is interrupted.

If the area difference is equal to or less than the allowable value, the process proceeds to the step of determining whether the bridge and bleeding of the cream solder are equal to or less than the allowable value. First, an inspection range is set for each cream solder printing prohibited area (step # 5).
0), the image within the inspection range captured by the camera 17 is binarized (step # 55), and the area of the cream solder area is measured by counting the number of pixels of the cream solder area (step # 60). And the measurement area is R
It is determined whether the value is equal to or less than the allowable value stored in the AM (step # 65).
Is determined (step # 70), a display indicating NG is made on the display, and the process is interrupted. If the value is equal to or less than the allowable value, it is determined that the print paste on the substrate P is OK (step # 75), a message indicating OK is displayed on the display, and the process ends.

Next, a fourth embodiment of the present invention will be described. In this embodiment, the control unit 9 is provided with a clogging determination unit that determines clogging of the screen S from an image of the screen S after screen printing captured by the camera 19 of the second imaging unit 5. This clogging determination means is constituted by a program stored in the ROM. As shown in FIG. 7, at a position before the retreat position of the screen S, a first cleaning unit 31 arranged below the screen S, and a retreat direction of the screen S with respect to the first cleaning unit 31. And second cleaning means 32 arranged side by side.

The first cleaning means 31 is freely movable in the vertical direction, is disposed between the screen S and the suction nozzle 33, and is disposed between the nozzle S for sucking the residue of the cream solder adhered to the screen S and the screen S. And a cleaning sheet 34 to be attached and detached to adhere the residue of the cream solder. The nozzle 33 has substantially the same width as the width of the screen S in a direction perpendicular to the plane of the paper, and is connected to a compressor (not shown). The cleaning sheet 34 is a long sheet having a width substantially equal to the width of the screen S, and is made of paper or nonwoven fabric having appropriate air permeability, and is impregnated with an organic solvent such as alcohol.

The cleaning sheet 34 is wound around a feed roller 35 extending in a direction perpendicular to the paper surface.
It is connected to a take-up roller 36 arranged in parallel with the roller 35 at a distance in the retreating direction of the screen S. A portion between the feeding roller 35 and the take-up roller 36 is guided by a pair of guide rollers 37 and 38 arranged in parallel above the rollers 35 and 36 so as to face the screen S. A motor (not shown) is connected to the winding roller 36, and when the motor is driven, the cleaning sheet 34 moves in the direction of the arrow.

The second cleaning means 32 is disposed below the screen S, is vertically movable, and is provided with a nozzle 39 for blowing air to the screen S, and is opposed to the nozzle 39 with the screen S interposed therebetween. A nozzle 40 that is vertically movable and sucks cream solder residue adhering to the screen S, and is disposed between the screen S and the nozzle 40, and comes into contact with and separates from the screen S to adhere the cream solder residue. And a cleaning sheet 41 to be cleaned. The nozzles 39 and 40 have substantially the same width as the width in the direction perpendicular to the paper surface of the screen S, and are each connected to a compressor (not shown). The cleaning sheet 41 is a long sheet having a width substantially equal to the width of the screen S, and is made of paper having appropriate air permeability.

The cleaning sheet 41 is wound around a pay-out roller 42 extending in the direction perpendicular to the plane of the drawing, and its leading end is connected to a take-up roller 43 arranged in parallel with the feed roller 42 at an interval above. Have been. Roller 4
2 and 43, the screen S is formed by a pair of guide rollers 44 and 45 arranged in parallel below the roller 42.
The take-up roller 43 is guided by a guide roller 46 arranged in parallel below the roller 43.
Has been guided to. A motor (not shown) is connected to the roller 43.
1 moves in the direction of the arrow.

Next, the operation of the screen printing machine according to this embodiment will be described. First, the camera 19 of the second imaging means 5 moves in the directions of the X axis and the Y axis to image the screen S after screen printing, and the image is stored in the recognition board 24. This image is processed by the clogging determination means,
The clogging of the screen S is determined. The procedure will be described below with reference to the flowchart shown in FIG.

Information such as the area, shape, and position of each opening of the screen S is stored in the RAM in advance, and an inspection range is set for each opening of the screen S based on the information. (Step # 105). Next, the image within the inspection range captured by the camera 19 is binarized (step # 110), and the area of the cream solder area is measured by counting the number of pixels of the cream solder area (step # 115). Then, the allowable value of the area of the cream solder region is stored in the RAM in advance, and it is determined whether the measured area is equal to or smaller than the allowable value (step # 120). If the measured area is larger than the allowable value, it is determined as NG (Step # 125), a display indicating NG is made on the display, and the screen S is cleaned by the first and second cleaning means 31 and 32 ( (Step # 130), the process returns to Step # 105, and the clogging of the opening of the screen S is determined again. If the measured area is equal to or smaller than the allowable value, it is determined to be OK (step # 135), a display indicating OK is displayed on a display (not shown), and the process ends.

The cleaning of the screen S by the first and second cleaning means 31 and 32 will be described in detail. First, the screen support means 3 moves toward the retreat position, and the tip of the screen S is moved to the position of the first cleaning means 31. Reaches
The screen support means 3 stops. Next, the first cleaning means 31 moves upward and stops at a position where the cleaning sheet 34 contacts the lower surface of the screen S, and the squeegee 21 descends and contacts the upper surface of the screen S. Next, the screen supporting means 3 moves toward the retreat position, and the compressor connected to the nozzle 33 of the first cleaning means 31 is driven. As the screen supporting means 3 moves, the lower surface of the screen S is wiped by the cleaning sheet 34, and the cream solder and the flux adhered to the lower surface of the screen S
3 sucks onto the cleaning sheet 34. Note that the squeegee 21 is in contact with the upper surface of the screen S, and the screen S surely adheres to the cleaning sheet 34, so that highly effective cleaning can be performed.

When the tip of the screen S reaches the position of the second cleaning means 32, the screen support means 3 stops temporarily. Then, the nozzle 39 of the second cleaning means 32 rises,
It stops at a position slightly away from the lower surface of the screen S, and stops when the nozzle 40 and the cleaning sheet 41 descend and the cleaning sheet 41 contacts the upper surface of the screen S. Then, the screen support means 3 starts to move toward the retreat position again, the compressor connected to the nozzles 39 and 40 is driven, and the screen is jetted from the nozzle 39 to the lower surface of the screen S cleaned by the first cleaning means 32. The air is blown, the cream solder and the flux adhering in the opening are blown away, and the blown cream solder and the flux are sucked by the nozzle 40, adhere to the cleaning sheet 41, and soak.

As described above, the first and second cleaning means 31,
32, the upper and lower surfaces of the screen S and the inside of the opening are cleaned, and then the cleaning sheets 34, 41, the nozzles 33, 39, 4,
0 leaves the screen S and the screen support means 3 returns to the printing position. Then, the take-up roller 36 of the first cleaning unit 31 is driven, and the cleaning sheet 34 is fed by a predetermined amount.
An unused portion of the cleaning sheet 34 is fed to a position facing the screen S. Further, the take-up roller 43 of the second cleaning means 32 is driven, the cleaning sheet 41 is fed by a predetermined amount, and an unused portion of the cleaning sheet 41 is fed out to a position facing the screen S.

In the above-described embodiment, the screen S is cleaned based on the determination result of the clogging determination unit. However, the screen S may be cleaned periodically. Further, the screen S may be cleaned based on the determination result of the print paste quality determination unit.

In the above-described embodiment, the screen is cleaned by moving the screen with the cleaning means and the squeegee stopped. Alternatively, the cleaning means may be cleaned with the screen stopped. The screen may be cleaned by moving the squeegee.

The means for cleaning the screen S is not limited to the above embodiment, but can be constituted by variously combining the cleaning means described in the claims and existing cleaning means.

[0063]

As described above, according to the screen printer of the present invention, the camera for imaging the screen is separately provided, and the screen supporting means is movable in the Y-axis direction. It is possible to calculate the displacement between the substrate and the screen when the substrate is in contact with the substrate, so that even if there is a distortion in the mechanism for moving the substrate support table in the Z-axis direction, it is necessary to eliminate the displacement caused by the distortion. And the screen can be corrected.

Further, since the camera for imaging the substrate and the camera for imaging the screen are separated, a complicated optical system is not required unlike the case where one camera images both the substrate and the screen. Errors due to system distortion can be reduced.

Further, since each camera is set with the image incident surface facing downward, the print paste dropped from the screen does not adhere to the image incident surface of the camera.

Therefore, the displacement between the substrate and the screen can be corrected with high accuracy. Further, the screen printing machine of the present invention can move the screen supporting means in the Y-axis direction, and thus has an advantage that workability is good when performing internal maintenance.

According to a second aspect of the present invention, there is provided a screen printing machine further comprising: a print paste quality determining means for determining at least a positional shift of a print paste from an image of a substrate after screen printing captured by the first image capturing means. By correcting the displacement between the substrate and the screen based on the displacement information of the print paste from the print paste quality determining means, the displacement between the substrate and the screen can be corrected with higher accuracy. it can.

According to the screen printing machine of the third aspect, the control means periodically causes the first image pickup means to image the substrate after screen printing, and from the obtained image, the print paste good / bad judgment means judges whether the print paste is good or bad. Is determined, and the displacement between the substrate and the screen is corrected based on the positional displacement information of the print paste from the print paste quality determination means, thereby enabling the substrate support table, the screen support means, the first and second Even if a distortion due to a change over time occurs in the moving mechanism of the imaging means, an error due to the distortion can be reduced, so that the displacement between the substrate and the screen can be corrected with higher accuracy.

According to the screen printing machine of the fourth aspect, the clogging determining means for determining the clogging of the opening of the screen from the image of the screen captured by the second imaging means is provided, so that a high-quality printing paste is provided. Can be obtained.

According to the screen printing machine of the fifth aspect, the control means periodically causes the second image pickup means to image the screen after screen printing, and from the obtained image, the clogging determination means causes the opening of the screen to be opened. By determining the clogging, a substrate having a high-quality printing paste can be stably obtained.

According to the screen printer of the sixth aspect, a gas blowing means which is disposed above or below the screen, is movable vertically, and blows gas to the screen;
By providing a cleaning means which is disposed to face the gas blowing means with the screen interposed therebetween, and which is freely movable in the vertical direction, and which has a suction means for suctioning the residue of the printing paste adhered to the screen, high quality is provided. A substrate having a printing paste can be obtained. Also, if the screen support means is Y
Since the cleaning means is movable in the axial direction, the cleaning means does not require a mechanism for moving in the horizontal direction, has a simple structure, and can be manufactured at low cost.

According to the screen printing machine of the present invention, the cleaning means is disposed between the screen and the suction means, and comes into contact with and separates from the screen, and has a breathable cleaning sheet for adhering the residue of the printing paste. With this arrangement, a substrate having a higher-quality printing paste can be obtained.

According to the screen printing machine of the eighth aspect, a suction means which is vertically movable below the screen and sucks the residue of the printing paste adhered to the screen,
A cleaning means provided with a cleaning sheet disposed between the screen and the suction means, which is in contact with and separated from the screen, is movable in the vertical direction, and has an air-permeable cleaning sheet for attaching the residue of the printing paste, is provided on the screen. The screen is pressed against the cleaning sheet by the relative movement of the printing paste application squeegee,
Since the screen is cleaned while the cleaning sheet is in close contact with the screen, the screen can be effectively cleaned, and a substrate having a high-quality printing paste can be obtained.

According to the screen printing machine of the ninth aspect, the control means causes the cleaning means to clean the screen when the judgment result of the print paste quality judgment means or the clogging judgment means is negative. A substrate having a high-quality printing paste can be stably obtained, and the burden on the operator can be reduced.

According to the control method of the screen printing machine of the tenth aspect, the displacement of the camera of the first imaging means and the camera of the second imaging means and the distortion of the second moving mechanism for moving the substrate support table in the Z-axis direction. Therefore, the displacement between the substrate and the screen can be corrected with high accuracy.

According to the control method of the screen printing machine of the eleventh aspect, it is possible to reduce the error in the recognition of the position of the substrate and the screen due to the distortion of the mechanism for moving the cameras of the first and second imaging means. And the screen can be corrected with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a screen printing machine according to a first embodiment of the present invention.

FIG. 2 is a view taken along the line AA of FIG. 1;

FIG. 3 is a right side view of the screen printing machine in FIG.

FIG. 4 is a block diagram of a control circuit of the screen printing machine in FIG. 1;

FIG. 5 is a flowchart showing a procedure for determining the quality of a print paste by a print paste quality determination unit mounted on a screen printing machine according to a third embodiment of the present invention.

FIG. 6 is a flowchart illustrating a procedure for determining the quality of a print paste by a print paste quality determination unit mounted on a screen printing machine according to a third embodiment of the present invention.

FIG. 7 is a diagram showing a main part of a fourth embodiment of the present invention.

FIG. 8 is a flowchart illustrating a procedure for determining clogging of an opening of a screen by a clogging determination unit mounted on a screen printing machine according to a fourth embodiment of the present invention.

[Description of Signs] 2 Substrate support table 3 Screen support means 4 First imaging means 5 Second imaging means 9 Control means 10 First moving mechanism 11 Rotating mechanism 12 Second moving mechanism 16 Moving mechanism of screen supporting means 3 17 First Camera of imaging means 4 19 Camera of second imaging means 5

Claims (11)

[Claims] 1. A first moving mechanism for moving in a direction of an X axis extending in a horizontal direction, a second moving mechanism for moving in a direction of a Z axis extending in a vertical direction, and a rotating mechanism for rotating in a horizontal plane. A screen supporting means disposed above the board supporting table and having a moving mechanism for moving in the Y-axis direction extending in the horizontal direction; and a substrate supporting table and the screen supporting means. A first imaging unit having a camera arranged between the first and second substrates, the camera being capable of moving in the directions of the X axis and the Y axis, and imaging the substrate placed on the substrate support table; and A second imaging unit having a camera that is movable in the directions of the X axis and the Y axis and captures an image of a screen supported by the screen supporting unit; and before performing screen printing on the substrate, Perform position recognition of the substrate by imaging the substrate to the first imaging means,
The second image pickup means picks up the image of the screen to recognize the position of the screen, calculates the displacement between the substrate and the screen from the obtained position information of the substrate and the screen, and calculates the displacement between the substrate and the screen. A first moving mechanism and a rotating mechanism, and control means for driving the moving mechanism of the screen supporting means to correct the displacement. 2. A printing paste quality determining means for determining at least a positional shift of a printing paste from an image of a board after screen printing captured by the first imaging means, wherein the control means determines whether the printing paste is good or bad. 2. The screen printing machine according to claim 1, wherein the misalignment between the substrate and the screen is corrected based on the misalignment information of the printing paste. 3. The control unit periodically causes the first imaging unit to image the substrate after screen printing, and causes the print paste quality determination unit to determine the quality of the print paste on the substrate from the obtained image. 3. The method according to claim 2, wherein
A screen printing machine according to claim 1. 4. A clogging judging means for judging clogging of an opening of the screen from an image of the screen taken by the second imaging means. A screen printing machine as described in Crab. 5. The control means periodically causes the second imaging means to image the screen, and causes the clogging determination means to determine clogging of an opening of the screen from an obtained image. The screen printing machine according to claim 4, wherein 6. A gas blowing means which is disposed above or below the screen, is vertically movable, and blows gas to the screen, and is disposed so as to face the gas blowing means with the screen interposed therebetween. The screen printing according to any one of claims 1 to 5, further comprising a cleaning unit that is vertically movable and includes a suction unit that suctions a residue of the printing paste attached to the screen. Machine. 7. The cleaning device according to claim 1, wherein the cleaning unit is provided between the screen and the suction unit, and has a gas-permeable cleaning sheet that comes into contact with and separates from the screen and adheres the residue of the printing paste. The screen printing machine according to claim 6, wherein 8. A suction means, which is vertically movable below the screen and sucks a residue of the printing paste adhered to the screen, and is disposed between the screen and the suction means. A cleaning sheet having a cleaning sheet that is movable toward and away from the screen and is movable in the vertical direction and that has air permeability for adhering the residue of the printing paste, and a squeegee for applying the printing paste relatively moves on the screen. The screen printing machine according to claim 1, wherein the screen is pressed against the cleaning sheet. 9. The printing apparatus according to claim 6, wherein said control means causes said cleaning means to clean said screen when the judgment result of said print paste quality judgment means or said clogging judgment means is negative. Item 10. A screen printing machine according to any one of items 8. 10. The method of controlling a screen printing machine according to claim 1, wherein said first image pickup means takes an image of a substrate placed on said substrate support table, and The support table is raised to a printing position to cause the second imaging unit to image the substrate, and the position information of the substrate obtained by the first imaging unit and the position information of the substrate obtained by the second imaging unit And calculating a shift between the substrate and the screen so as to eliminate an error caused by the shift. 11. A calibration jig plate having a calibration mark on the surface and having a known position of the calibration mark is placed on the substrate support table, and the calibration mark is attached to the first and second calibration marks.
An image is taken by an imaging unit, and a difference between the position information of the calibration mark obtained by the first and second imaging units and the known position information of the calibration mark is calculated. The method according to claim 10, wherein the position of the substrate and the screen is recognized.