JP3285244B2 - Printing result inspection method and inspection device for screen printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for inspecting a printing result of a screen printing machine .
In particular, it relates to facilitation of creation of reference data for inspection .

[0002]

2. Description of the Related Art A screen printing machine prints a printing agent at a predetermined position on a plate to be printed, as in the case where an adhesive or cream solder is applied to a position where electronic components are bonded to a printed circuit board or a position where a lead wire is connected. It is a device,
It is known from Japanese Patent Publication No. In this screen printing machine, generally, a printing agent is printed on a printing plate through a through hole formed in a screen as a squeegee moves on the screen.

[0003] When a printing agent is printed on a printing plate in this way, printing may be defective. For example, printing agent may not be printed on all or some printing positions,
The printing amount may be insufficient, or the printing position may be shifted. Such printing failures occur because
The clogging of the screen through-hole with the printing agent occurs,
Depending on factors such as shortage of printing agent, misalignment of the screen and the plate to be printed, etc. For example, it is possible to determine whether there is a defect in printing.
The reference data is data used as a reference for judging whether or not there is a defect in the printing result. If there is a printing defect, the good printing is performed by removing the cause of the detected printing defect. It can be carried out.

For this reason, conventionally, for example, when cream-like solder is printed on a printed circuit board and the printed result is inspected, reference data is created as follows. The cream solder is actually printed on the printed circuit board, and the printed circuit board on which all of the printing amount, printing position and printing area are properly printed is used as a model board, and the cream solder printed on the model board is printed by a CCD camera. The reference data for imaging and inspecting the print amount, print position, print area, and the like are created. Further, reference data can be created using CAD data for creating a printed circuit board. . CAD data is data for forming a wiring pattern on a printed circuit board. Since the position where electronic circuit components such as electronic components, resistors, and capacitors are mounted can be determined from the wiring pattern, the amount of creamy solder printed can be determined from that position. , Print position, print area, and the like can be determined to create reference data.

[0005]

However, when the model board is created and the reference data is created, the cream-like solder is printed on the printed board until a proper reference data can be created. In other words, screen printing must be performed until a nearly optimal amount of creamy solder is printed at a substantially optimal position and area, etc.
Many printed boards are wasted, so that it takes time to create reference data, and there is a problem that the skill of an operator is required to create the reference data. When the reference data is created based on the CAD data, the CAD data needs to be processed, and the data creation is troublesome. Cream solder
Since the data is usually printed on a part of the wiring pattern defined by the CAD data, it is necessary to process the CAD data to create the reference data. Further, the CAD data is design data, and does not always represent a state of being properly printed using a screen, and may be incorrect as reference data for inspecting a print result. These problems are not limited to the case of printing creamy solder on a printed circuit board, but the case of printing a printing agent other than creamy solder on a printed circuit board, or the printing agent other than creamy solder on a printed board other than the printed circuit board. This is a problem that arises when printing is performed on a paper. The present invention
Inspect the printing result of screen printing made on the printing plate
The exact reference data used as the inspection criteria for the print results.
The object of the present invention is to make it easy to create data .

[0006]

Means for Solving the Problems, Functions and Effects of the Invention
Inspection of a printing result for a screen printing machine according to the invention of claim 1
The method is on the screen to solve the above problem
As the squeegee moves, it is formed on the screen
To print the printing agent on the printing plate through the multiple through holes
This is a method for inspecting the print result in a clean printer.
And at least one of the plurality of through holes of the screen.
Plane for obtaining an image of a part including the part in a plan view
Obtained in the visual image acquiring step and the planar visual image acquiring step.
Data creation process that creates reference data based on the image
And at least the plane view image acquisition step of the screen.
Through the through-hole that has acquired a planar view in the process,
Print status to get the print status of the printing agent printed on the printing plate
Acquisition process and the mark acquired in the printing status acquisition process
By comparing the printing condition of the printing material with the reference data,
And a print result inspection step of inspecting the result.
You. If an image of the screen in plan view is obtained, the position and area of the through hole can be known. At that time, it is not always necessary to obtain an image of the entire screen. For example, in general, printing defects are likely to occur in small through holes, and high printing accuracy is required, so that inspection may be performed only on small through holes. You only need to get it. Also, only the part where the through holes are concentrated, or the corner of the screen, etc.
An image of only a part with special circumstances may be acquired. The position and area of the through hole correspond to the position and area of the printing agent to be printed on the printing plate, and reference data such as the printing position and printing area of the printing agent can be created based on the planar view. . The volume of the through-hole can be known from the area of the through-hole and the thickness of the screen. This volume is the printing amount of the printing agent to be printed on the printing plate, and the reference data of the printing amount can be created. As described above, according to the first aspect of the present invention, the reference data can be created by acquiring an image of the screen in a plan view and adding data of the thickness of the screen as necessary. By looking at the screen used, the area, position, amount, and the like of the printing agent to be actually printed on the printing plate can be accurately known, and the reference data can be created with high accuracy. Further, unlike the case of creating a model substrate, it is not necessary to print a printing agent on a large number of plates to be printed, and it is possible to quickly and inexpensively create reference data without requiring skill of an operator. Therefore, according to the first aspect of the invention,
Using the reference data created accurately and accurately
Inspection of the result of screen printing made on the printing plate
it can. Printing for a screen printing machine according to the invention of claim 2
In the result inspection method, the reference data creation step includes:
Printing position and printing surface of printing agent to be printed on the printing plate
The reference data for at least one of the product
Including the step of creating. According to this section, printed on the printing plate
At least the printing position, printing area, and printing amount of the printing agent
One is inspected, and printing of printing agent is performed based on the inspection result.
Misalignment, screen clogging, shortage of print volume
At least one solution can be achieved. Claim 3
In the printing result inspection method for screen printing machine according to Ming
Is a plan view image of the through hole in the plan view image obtaining step.
Acquisition and marking of the printing agent in the printing state acquisition step
At least one of the acquisition of the printing state is performed by the imaging device.
This is done based on the image. Screen according to claim 4
In the printing result inspection method for a printing press, the imaging device
Imaging, the imaging device parallel to the screen
X and Y axes that are orthogonal to each other in a single plane
To the desired position on the XY coordinate plane
Will be According to this section, the imaging device is a device that
Moved to the desired position and the multiple
Can be imaged. There
Is moved to an arbitrary position on the printing plate
And any of the multiple printing agents printed on the printing plate
Images can be taken. The screen according to the invention of claim 5
In the print result inspection method for printing presses, the screen
Inspection by the printing result inspection method for
Where the printing on the printing plate is performed by the printing press
Are performed at different locations.

[0007] A screen printing machine according to the invention of claim 6
In order to solve the above-mentioned problems, the printing result inspection apparatus
As the squeegee moves on the clean,
Printing agent through the multiple through holes
Inspect the print result on a screen printer that prints
Device, wherein the plurality of through-holes of the screen.
An image of a part including at least a part in a plan view
A planar view image acquiring means for acquiring the planar view image acquiring means;
To create reference data based on the images acquired in
By the quasi-data creating means and the screen printing machine,
At least by the plane view image acquisition means of the screen.
Through the through hole where the planar image was acquired
Print status acquisition method for acquiring the print status of the printed printing agent
And the printing agent obtained by the printing state obtaining means.
Check the print result by comparing the print state with the reference data.
And a print result inspecting means for inspecting. Book
In the paragraphs, at least the function according to claim 1 and
The effect is obtained. Each of the features described in claims 2 to 5,
This section is also applicable. The screen according to the invention of claim 7
Printing result inspection device for screen printing machine, the screen printing
Machine, a planar view image acquiring means and a printing state acquiring means,
At least one in a plane parallel to the screen
Defined by an X axis and a Y axis that are orthogonal to each other.
Moving device for moving to an arbitrary position in an XY coordinate plane
It is comprised so that it may contain.

[0008]

[0009]

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings, taking as an example the case where the present invention is applied to a screen printer for printing creamy solder on a printed circuit board.

As shown in FIGS. 1 and 2, the screen printing machine of this embodiment includes a screen printing device 10, a substrate conveyor 12, a screen transport device 14, a screen storage device 16, and a screen cleaning device 18. The board conveyor 12 is provided on a bed 22 provided at a fixed position, and has a fixed rail 24 and a movable rail 26 arranged in the X-axis direction (vertical direction in FIG. 1). A rope (not shown) is wound around the inside of each of the rails 24 and 26 endlessly, and a printed board 28 as a plate to be printed is placed on the rope, and the rope is moved to move in the X-axis direction. Conveyed. A plurality of screw shafts 30 are bridged between the fixed rail 24 and the movable rail 26, and the movable rail 26 is moved toward and away from the fixed rail 24 by rotating the screw shaft 30. Are set in accordance with the dimensions of the printed circuit board 28.

The screen printing apparatus 10 is disclosed in
The configuration is almost the same as that of the screen printing apparatus described in Japanese Patent No. 84871, and will be briefly described. The screen printing apparatus 10 includes a printed board positioning and supporting device 34, a screen positioning and supporting device 36, a squeegee device 38, and a substrate pressing device 40. Among these devices, the substrate holding device 40 is provided on the bed 22 together with the substrate conveyor 12. The board holding device 40 has a board holding plate 42 that is moved in the X-axis direction, and plays a role of holding the printed board 28 from above when the printed board 28 is supported by the printed board positioning and supporting device 34.

Printed circuit board positioning and supporting device 34, screen positioning and supporting device 36, and squeegee device 38
Is provided on a movable table 46 provided on the bed 22 so as to be movable in a Y-axis direction orthogonal to the X-axis direction. When the width of the board conveyor 12 is changed, the movable table 46 is moved in the same direction as the movable rail 26 by a half distance, and when the width of the board conveyor 12 is changed, Y of the printed board positioning support device 34, the screen positioning support device 36, and the squeegee device 38
The center in the axial direction coincides with the center in the Y-axis direction of the board conveyor 12.

The printed board positioning and supporting device 34 is provided so as to be able to move up and down, and has a board supporting base 50 as a printed board supporting base which is raised and lowered to four levels by a multi-stage cylinder (not shown). The substrate supporting base 50 sucks the printed circuit board 28 by vacuum while sandwiching the printed circuit board 28 together with the substrate pressing plate 42, and rises to a position where the cream solder is printed.

The screen positioning support device 36 and the squeegee device 38 are supported by a frame 54 mounted on a movable base 46 so as to be rotatable around an axis parallel to the Y-axis direction. A screen support 56 is provided on the frame 54.
Are fixed, and as shown in FIG. 3, the screen 58 and a screen frame 60 fixed to the peripheral edge thereof are supported.

As shown in FIGS. 4 and 5, a large number of through holes 62 are formed in the screen 58. These through holes 62 are formed at positions corresponding to the positions where the lead wires of the flat package type electronic component of the printed circuit board 28 are connected and the positions where the electrodes such as resistors and capacitors are connected. The thickness of the screen 58 is partially different as shown in FIG. For example, the lead wires of electronic components are thin,
If the distance between adjacent lead wires is narrow, a short circuit may occur unless the amount of creamy solder is reduced to a small amount. Therefore, the width of the through hole 62 is set to a size corresponding to the thickness and interval of the lead wires, The thickness of the screen 58 is reduced, and the print amount is reduced.

The screen support 56 is a rectangular frame, and two frames parallel to the X-axis direction (vertical direction in the drawing) are provided on the opposite side to the screen transport device 14. The Y-axis direction position setting device 64 is provided at a distance in the X-axis direction, while the other frame portion has a Y-axis direction pressing device 6 corresponding to the two Y-axis direction position setting devices 64, respectively.
6 are provided. In addition, Y of the screen support 56
Of the frame portions parallel to the axial direction (the left-right direction in the figure), the frame portion on the frame 54 side is provided with one X-axis direction position setting device 68.
The other frame portion is provided with an X-axis direction pressing device 70, and these Y-axis direction and X-axis direction position setting devices 64 and 68, and the Y-axis direction and X-axis direction pressing devices. 6
6, 70 constitute the screen positioning support device 36.

The Y-axis position setting device 64 is a screen 5
8 for setting the position in the Y-axis direction, and as shown in FIG. 6, a positioning lever 72 rotatable around a vertical axis.
It has. The lever 72 is connected to the screen support 56.
And two arm portions 76 and 78 rotatably supported by a bracket 74 fixed to the arm and extending in directions different in phase. Rollers 80 and 82 are rotatably attached to the distal ends of the arms 76 and 78, respectively. The return spring 84 urges the upper arm 76 in a direction away from the screen frame 60, and Arm part 78
Roller 82 is in contact with the tip of the push rod 86.

The push rod 86 is fitted to a block 88 fixed to the bracket 74 so as to be slidable in the X-axis direction, and is screwed to a screw shaft 92 connected to an output shaft of a step motor 90. It is moved in the X-axis direction by the rotation of the step motor 90. Step motor 90
The forward rotation of the push rod 86 advances (FIG. 6).
Is moved to the left), the positioning lever 72 rotates against the biasing force of the return spring 84, and the upper arm 76 approaches the screen frame 60. Step motor 9
With the rotation in the reverse direction of 0, the arm portion 76
To separate from the screen frame 60. Therefore, by appropriately setting the movement position of the push rod 86, the upper arm portion 76,
8 in the Y-axis direction can be set.

As shown in FIG. 3, the Y-axis direction pressing device 66 has a push lever 98 provided on the screen support 56 so as to be rotatable around a vertical axis by a shaft 96. The push lever 98 has a dogleg shape and is connected at one end to the piston rod 102 of the air cylinder 100. The air cylinder 100 is attached to the screen support base 60 so as to be rotatable about a vertical axis, and the push lever 98 is located on the side opposite to the side connected to the piston rod 102 when the piston rod 102 is at the retracted end position. Is located outside the side surface parallel to the Y-axis direction of the screen frame 60 as shown by the solid line, while approaching the screen frame 60 when the piston rod 102 is moved toward the forward end position. The screen frame 6 as shown by the two-dot chain line.
0 engages with the side surface parallel to the X-axis direction of the screen frame 60.
Is pressed against the Y-axis direction position setting device 64, whereby the screen frame 60 is positioned in the Y-axis direction.

The push lever 98 of the Y-axis direction pressing device 66 provided downstream of the screen support 56 in the printed board conveying direction is attached to the upper portion of the shaft 96 and is located above the screen support 56. An arm portion 104 and an arm portion 106 attached to a lower portion of the shaft 96 and located below the screen support 56.
As shown by the solid line, when the push lever 98 is rotated to a position where the screen frame 60 is not pressed, the arm portions 104 and 106 move toward the screen transport device 14 in the Y-axis direction of the screen frame 60 (the right side in FIG. 3). , And the movement to the downstream side (downward in FIG. 3) in the printed circuit board transport direction in the X-axis direction.

The position setting device 68 in the X-axis direction is constructed similarly to the position setting device 64 in the Y-axis direction. A positioning lever 114 having two arms 110 and 112 is used to push a stepping motor 118 for pressing a push rod 116. The screen frame 60 is set in the X-axis direction by being rotated by the forward and backward movements and by the urging force of a return spring (not shown).

As shown in FIG. 7, the X-axis direction pressing device 70 has a
The screen frame 60 is pushed by being rotated by 24. An elongated hole 126 is formed in the screen support 56, and the push lever 122 is attached so as to be rotatable around an axis parallel to the Y-axis direction. One end of the push lever 122 is connected to the air cylinder 12.
4 is rotatably connected to the piston rod 128, and the other end of the push lever 122 projects on the screen support 56 and pushes the screen frame 60 by the expansion and contraction of the piston rod 128.
Is moved from the upper surface to a position retracted into the elongated hole 126.

Further, on the screen support 56,
A fixing cylinder 134 is provided at each corner.
These fixing cylinders 134 are provided downward, and when positioning the screen frame 60, the piston rod is at the contracted end position and is separated from the screen frame 60. However, after positioning, the piston rod is extended and the screen frame 60 is extended. It is fixed to the screen support 56. The two fixing cylinders 134 provided on the downstream side (the lower side in FIG. 3) in the transport direction of the printed board 28 are provided at positions where the movement of the screen frame 60 in the same direction is not hindered.

Next, the squeegee device 38 will be described.
As shown in FIG. 1, two guide rods 140 are provided between the frame 54 and a gate-shaped frame 138 erected on a portion of the screen support 56 opposite to the frame 54. And the slide 14
2 are slidably fitted. A squeegee unit 144 shown in FIG. 8 is attached to the slide 142 so as to be able to move up and down. Let me do. The slide 142 is screwed to the feed screw 148 with a nut 147, and the feed screw 148 is
As a result, the slide 142 is moved, and the squeegee unit 144 is linearly reciprocated in the X-axis direction.

As shown in FIG. 8, the squeegee unit 144 includes a stirrer 154 that is long in the width direction of the screen 58,
And a syringe 158 in which the creamy solder 156 is accommodated. The syringe 158 is a casing 1 of the stirrer 154.
60 and is detachably attached to the casing 16.
0, the creamy solder 156
Flows into the casing 160 by the low-pressure nitrogen gas supplied into the syringe 158 and its own weight. A float 162 floats on the cream solder 156. The float 162 is formed by fitting an iron ring 164 around the outer periphery of a disk made of synthetic resin, and the ring 164 is detected by a first magnetic switch 166 provided outside the syringe 158, whereby the cream-like shape in the syringe 158 is formed. It is detected that the amount of the solder 156 has reached the lower limit amount. Outside the syringe 158 is also the first magnetic switch 1
A second magnetic switch 168 is provided at a position above 66 so as to detect that the amount of the creamy solder 156 in the syringe 158 has reached the upper limit.

Further, the syringe 158 is connected to a creamy solder replenishing device 172 by a hose 170. The cream-like solder replenishing device 172 is
The cream-like solder placed on the top 2 is constantly stirred by a stirrer to maintain a viscosity suitable for printing. This creamy solder replenishing device 172
Automatically supplies creamy solder to the syringe 158 based on the supply command.

The casing 160 of the agitator 154 is rotatably mounted on a frame (not shown) which is raised and lowered by a lifting cylinder 146. Casing 1
A shaft 176 is rotatably accommodated in the shaft 60, and a stirring roller 178 is eccentrically attached to the shaft 60.
When the shaft 176 is rotated by a drive motor (not shown), the agitating roller 178 rotates to agitate the cream-like solder 156 in the casing 160 and maintain the viscosity suitable for printing. An opening 180 is provided on the lower surface of the casing 160.
Is formed, and a pair of rubber squeegee members 1 are formed.
82 are attached to form a discharge port 184. These squeegee members 182 are such that the casing 160
6, the squeegee member 182 on the upstream side contacts the screen 58 in the moving direction of the squeegee unit 144, and the squeegee member 182 on the downstream side slightly moves from the screen 58 in the moving direction of the squeegee unit 144. It is assumed to be in a raised state.

The screen 58 needs to be replaced when the type of the printed circuit board 28 is changed. At the time of screen replacement, the screen 58 is
4, the screen is pulled out from the screen support 58 and is stored in the screen storage device 16, and another screen 58 is taken out of the screen storage device 16 and positioned on the screen support 56.

The screen transport device 14 has an X-axis slide 188 that moves in the X-axis direction, and a Y-axis slide 190 provided on the X-axis slide 188 so as to be movable in the Y-axis direction. The X-axis slide 188 is slidably fitted to a pair of guide rails 192 arranged in the X-axis direction, and is screwed to a ball screw 194. By being rotated by 196, it is moved in the X-axis direction.

A guide rail and a ball screw (not shown) are provided on the X-axis slide 188 in the Y-axis direction. The Y-axis slide 190 is rotated by the Y-axis direction driving motor 198 to rotate the Y-axis slide 190. Moved in the axial direction. The X-axis slide 188 is also provided with a plate-shaped guide member 200 parallel to the Y-axis direction.

The Y-axis slide 190 has a long shape extending in the Y-axis direction, and engagement members 202 and 204 having a U-shaped cross section are attached to the lower surface of the distal end portion. The engaging member 202 is lowered by the lowering cylinder 206 and is urged upward by a spring (not shown), and the pair of U-shaped side walls is attached in a direction parallel to the X-axis direction. The engaging member 204 is also moved up and down by the lowering cylinder 208 and the spring in the same manner as the engaging member 202, but a pair of U-shaped side walls are attached in a direction parallel to the Y-axis direction.

Also, on the rear end side of the Y-axis slide 190,
An engagement pin 212, an engagement member 214 having a U-shaped cross section, and a support member 216 are attached. Engaging member 214
Are mounted so that a pair of U-shaped side walls are parallel to the Y-axis direction.
14 is raised and lowered by a lowering cylinder and a spring. Further, the support member 216 is provided in parallel with the X-axis direction.

Further, a laser displacement sensor 220 is attached to the tip of the Y-axis slide 190. As shown in FIG. 9, the laser displacement sensor 220 emits a laser beam emitted from a laser beam generator 222 to a projection optical system 224.
And irradiates the cream-like solder 156 printed on the printed circuit board 28 with the reflected light.
6, the light is focused on the semiconductor position detecting element 228, and the reflected light focusing position is calculated by the analog processing circuit 230. Cream solder 156
Since the light condensing position on the semiconductor position detecting element 228 changes depending on the height of the solder paste, the position on the printed circuit board 28 where the cream solder 156 is printed and its height can be determined by calculating the light condensing position.

A CCD camera 232 is attached to the Y-axis slide 190 at the tip of the laser displacement sensor 220 as shown in FIG. CCD camera 232 is X
The shaft slide 188 and the Y-axis slide 190 are moved to arbitrary positions in a horizontal plane.

The screen accommodating device 16 has a screen accommodating portion 236 provided in two stages in a casing 234 thereof.
As the casing 234 is raised and lowered by the lifting cylinder 238, the casing 234 is alternatively positioned at the screen transfer position. Automatic screen replacement is described in
This is similar to the screen printing machine described in JP-A-317768, and will be briefly described.

When the screen 58 is replaced in accordance with the change of the type of the printed circuit board 28, the Y-axis slide 190
Is engaged with the screen frame 60 and the screen frame 60 is pulled out from the screen support base 56 by approximately half the length in the Y-axis direction. The screen frame 60 is pulled out from the screen support 56 while being guided by the guide member 200. When the X-axis slide 188 is moved in that state, the screen frame 60 is pushed by the guide member 200 and moved toward the screen storage device 16 by a distance of about half the length in the X-axis direction. The screen frame 60 is accommodated in the upper screen accommodating portion 236 by the engagement member 214 being engaged with the screen frame 60 and moving in the X-axis direction. Then, the lower screen accommodating portion 236 is positioned at the screen transfer position, and the screen 58 to be used next is conveyed onto the screen support 56 in the reverse procedure to the case where the screen 58 is accommodated, and positioned. Used for screen printing.

Next, the screen cleaning device 18 will be described. The screen cleaning device 18 is provided on the downstream side (the lower side in FIG. 1) of the screen printing device 10 of the bed 22 in the transport direction of the printed circuit board 28. As shown in FIG. 1, a pair of guide rails 248 is provided above the substrate conveyor 12 and the screen cleaning device 18 of the bed 22, and serves as a guide when the screen frame 60 is lowered from the screen support 56.

The screen cleaning device 18 is provided with a width slightly smaller than the width when the fixed rail 24 and the movable rail 26 of the board conveyor 12 are opened to the maximum.
As shown in FIG. 2, the bed 22 includes a lifting table 250 that can be raised and lowered. Four guide rods 252 are fixed to the lower surface of the elevating table 250 and slidably fitted to a bush 254 provided in the bed 22.
The piston rod 258 of the lifting cylinder 256 housed in the bed 22 is connected to the piston rod 258.
The elevating table 250 is moved up and down by the expansion and contraction of 58.

On the elevating table 250, a pair of guides 2
62 are provided in a direction extending in the X-axis direction,
4 are slidably fitted. Slide 264 is shown in FIG.
As shown in FIG. 0, the ball screw 266 provided on the elevating table 250 is screwed with a nut 268 (see FIG. 2). Moved in the direction. On this slide 264, a brush 274 long in the Y-axis direction is attached by a shaft 276 so as to be rotatable around an axis parallel to the Y-axis direction.

As shown in FIG. 2, the shaft 276 is rotated by the rotation of a rotation driving motor 280 transmitted by a pulley, a belt 278, and the like fixed to one end thereof.
On the slide 264, as shown in FIGS. 10 and 11, the solvent ejection nozzle 284 and the solvent supply device 28 are provided.
6 is provided, and a solvent for removing the creamy solder 156 is jetted from the solvent jet nozzle 284 toward the screen 58 by the principle of spraying.
A vacuum suction unit 290 is further provided on the slide 264 along the brush 274. The vacuum suction device 290 is connected to the vacuum device 292 (see FIG. 12), and suctions the creamy solder 156 attached to the brush 274 by supplying the vacuum.

The screen printing machine is controlled by a control device 300 shown in FIG. This control device 300
Is mainly composed of a computer having a CPU 302, a ROM 304, a RAM 306 and a bus 308 connecting them. An input interface 310 is connected to the bus 308, and the first and second magnetic switches 16 are connected to the bus 308.
6,168, laser displacement sensor 220, CCD camera 2
32 and the input device 311 are connected. The input device 311 includes numerical keys, alphabet keys, operation keys, and the like, and inputs data such as the thickness of the screen 58 and the like, the board conveyor 12 and the screen transport device 14.
And the like are used for manual operation of an apparatus constituting the screen printing machine.

An output interface 312 is also connected to the bus 308, and drive circuits 316, 318, 320,
322, 324, 326, 328, 330, 332, 3
Step motors 90 and 118, fixing cylinder 134, pressing cylinders 100 and 124, solder replenishing device 172, elevating cylinder 256, moving motor 270, and rotation driving motor 28 via 34, 336, 338 and 340.
0, solvent supply device 286, vacuum device 292, X-axis direction driving motor 196, Y-axis direction driving motor 198
Is connected. In addition, in addition to these, a motor for driving the screen printing apparatus 10 and the board conveyor 12 and the like are connected, but here, only those closely related to the description of the present invention are illustrated, and connection of other members is illustrated. Is omitted from the drawing.

Next, the operation will be described. Prior to the start of screen printing, the screen 58 is positioned on the screen support 56 and is imaged by the CCD camera 232. In this case, the entire screen 58 is not imaged, but only the range specified by the operator.
In the printed circuit board 28, a position where a printing failure occurs, such as a shortage of a printing amount or a shift of a printing position, is generally determined, and a portion corresponding to the position on the screen 28 is imaged.

At the time of image pickup, a member for absorbing light is placed below the screen 58, and the image is distinguished between the through-hole 62 and the portion other than the through-hole 62 of the screen 58 depending on the presence or absence of reflected light. The operator instructs the movement of the X-axis slide 188 and the Y-axis slide 190 using the input device 311 to move the CCD camera 232 to a desired imaging position. At this imaging position, an area surrounded by a dashed line on the screen 58 is imaged as shown in FIG. 4, and the image acquisition position data of the CCD camera 232 and the imaging data are stored in the RAM in association with each other. Further, the thickness of the screen 58 is known in advance by the design document of the screen 58, and the thickness of the screen 58 at the image acquisition position is input by the operator at the same time as the imaging, and is stored in the RAM together with the image acquisition position data and the imaging data. You.

When the entire portion of the screen 58 to be imaged has been imaged, the controller 300 prints the cream solder print position (including the planar shape) based on the image acquisition position data, the image data, and the thickness data. ), Print area and print amount reference data are created. Reference position data of the through hole 62 in the screen 58 is created based on the image acquisition position data and the imaging data. In this case, when the through hole 62 is rectangular and square, the positions of three vertices are obtained and used as reference position data. When the through hole 62 is circular, the center position is obtained and the reference position data is obtained. It is said. The reference position data is stored in the RAM 306 in association with the number of the imaging range.

The area of the through hole 62 is calculated based on the image data, and the reference area data is stored in the RAM 306 in association with the position data of the through hole 62. further,
Based on the reference area data and the thickness data,
Is obtained. The volume of the through hole 62 indicates the print amount of the creamy solder 156, and print amount data is created. The print amount data is stored in the RAM 306 in association with the position data of the through hole 62.

At the time of screen printing, the board conveyor 12
Is adjusted to a size corresponding to the width of the printed circuit board 28. Then, when the printed board 28 is transported to a position directly below the screen 58 by the board conveyor 12, the printed board 28 is positioned and supported by the board support table 50, raised to the printing position, and brought into close contact with the lower surface of the screen 58. In this state, the squeegee unit 144 is moved, and the creamy solder 156 is attached to the printed circuit board 28 via the screen 58.
Is printed.

After the printing is completed, the printed board 28 is lowered to be separated from the screen 58, carried out to the downstream side of the screen printing apparatus 10 by the board conveyor 12, and positioned by a positioning device (not shown). Next, the reference mark on the printed circuit board 28 is read by the laser displacement sensor 220, and the printing state of the creamy solder 156 is detected. The movement of the X-axis slide 188 and the Y-axis slide 190 of the screen transfer device 14 causes the laser displacement sensor 220 to move on the printed circuit board 28 and print the creamy solder 15.
In this case, only the position and height of the creamy solder 156 within the range corresponding to the imaging range of the screen 58 previously imaged by the CCD camera 232 are detected. The position data of the through hole 62 is corrected based on the positioning error of the printed circuit board 28 calculated based on the reading of the reference mark, and the movement data of the laser displacement sensor 220 at the time of imaging the cream solder 156 is created. The laser displacement sensor 220 is moved based on the data, and the position and height of the creamy solder 156 are detected.

After the detection, the printed cream solder 156
Each time, the print position, print area, and print amount are calculated. The actual print position data and the actual print area data are obtained from the image data, and are stored in the RAM 306 in association with the number of the detection range (the same as the number of the imaging range at the time of screen imaging). The print amount is obtained from the height of each part of the creamy solder 156, and the actual print amount data is stored in the RAM 306 in association with the number of the detection range.

Next, in the control device 300, the print result is inspected based on the reference data. The error of the printing position, the printing area and the printing amount and the pass / fail are checked.

First, the printing area is checked. The actual print area data is compared with the reference area data. If the actual area is equal to or more than a certain ratio of the reference area, the result is judged as pass, and if the actual area is less than the predetermined ratio, it is judged as fail. If the distribution of the positions where the cream solder 156 is printed is acceptable at most of the printing positions but rejected at only a part of the printing positions, the cause may be a hole in the screen 58. And the screen cleaning device 18 is operated.

First, the fixing of the screen frame 60 by the fixing cylinder 134 is released, and the pressing of the screen frame 60 by the pressing devices 70 and 66 in the X-axis direction and the Y-axis direction is released. The X-axis slide 188 and the Y-axis slide 190 are moved so that the engagement member 204 is engaged with a frame portion of the screen frame 60 parallel to the Y-axis direction. The screen cleaning device 1 is guided from the screen support 56 by the rail 248.
8 is pulled out.

In this state, after the board conveyor 12 is spread to the maximum distance, the lift 250 is raised and the brush 2
74 is brought into contact with the lower surface of the screen 58 and the brush 2
74 is moved along the screen 58 by the slide 264 while being rotated, and the creamy solder 156 clogged in the small hole of the screen 58 is removed. At this time, the solvent is ejected from the screen 5 by the solvent ejection nozzle 284.
8, the cream-like solder 156 attached to the screen 58 is removed, and the cream-like solder 156 attached to the brush 274 is sucked by the vacuum suction device 290, and the cream-like solder 156 clogged in the small hole of the screen 58 is removed. Cleanly removed.

Whether the printed amount of the cream solder 156 is smaller than the normal amount is determined by whether the printed cream solder 1
This is performed by comparing the actual print amount and the reference print amount for each of 56. If the number of positions where the actual print amount is equal to or less than the predetermined ratio of the reference print amount is equal to or more than the predetermined number, the cream solder 156 in the syringe 158 has decreased, and an operation command is issued to the cream solder replenishing device 172, The cream solder 156 is supplied to the syringe 158. This replenishment is performed at such a small pressure that the cream solder 156 is not discharged from the discharge port 184 until the ring 164 of the float 162 is detected by the second magnetic switch 168.

When the shortage of the cream solder 156 in the syringe 158 is detected by the first magnetic switch 166, the cream solder 156 is supplied by the cream solder replenishing device 172 based on the detection. However, the failure of the first magnetic switch 166 or the control device 3
00, a lack of cream solder 156 is not detected, or even if it is detected,
6 may not be replenished. In this case, the shortage of the creamy solder 156 is detected based on the printing state on the printed circuit board 28 as described above, and the creamy solder 156 is supplied based on the detection, so that printing is continued without any trouble. be able to. The occurrence of an abnormality in the first magnetic switch 166 or the control device 300 is determined by the first magnetic switch 1
Because the cream-like solder 156 is supplied and the second magnetic switch 168 emits a signal even though the signal is not supplied from 66, or the cream-like solder 156 is supplied based on the detection of the printing state. understand,
By storing this information, it is possible to use it for abnormality diagnosis and maintenance of the apparatus.

Whether the printed position of the cream solder 156 is deviated from the normal position depends on whether the cream solder 15
For each of Nos. 6, it can be found by comparing the actual print position with the reference print position. If the displacement of the printing position is equal to or larger than the allowable amount, the position of the screen 58 is corrected. In this case, the correction direction and the correction amount of the position of the screen 58 are calculated. First, the fixing of the screen frame 60 by the fixing cylinder 134 and the pressing by the pressing devices 66 and 70 are released, and then the stepping motors 90 and 118. Is activated, and the positions of the positioning levers 72 and 114 are corrected.
After the correction, the screen frame 60 is pressed by the pressing devices 70 and 66 in the X-axis direction and the Y-axis direction.
2, 114, the screen 5
The position 8 is corrected to a position where the creamy solder 156 is printed on the printed circuit board 28 without displacement. A screen position for automatically correcting the position of the screen 58 on the screen support 56 by the position setting devices 68 and 64 in the X-axis direction and the Y-axis direction and the pressing devices 70 and 66 in the X-axis direction and the Y-axis direction. It functions as a correction device.

As is apparent from the above description, in the present embodiment, the CCD camera 232 constitutes a plan view image acquisition means for acquiring an image of the screen 58 in plan view.
The control device 300 constitutes reference data creation means.

In the above embodiment, the planar view image of the screen 58 is obtained by the CCD camera 232 and the creamy solder 156 is detected by the laser displacement sensor 220.
Alternatively, it may be obtained by the laser displacement sensor 220.

In the above embodiment, the laser displacement sensor 220 is moved in the X-axis direction and the Y-axis direction to detect the printed cream-like solder 156, but the laser displacement sensor 220 is moved above the detection position. Then, the cream-like solder 156 may be detected by changing the irradiation direction of the laser beam.

Further, the CCD camera may obtain an image in a plane, or may obtain an image in a line. In any case, it is desirable to use a color CCD camera to distinguish between the printed circuit board 28 and the creamy solder 156.

In the above embodiment, the screen 58
Is a plane view in which the screen 58 is attached to a screen printing machine and the CCD camera 2 provided in the screen printing machine.
32, but a special imaging device is provided separately from the screen printing machine,
8 may be obtained.

It is also possible to provide a function of detecting a solder bridge connecting the cream solders 156 printed at different printing positions. One of the causes of the occurrence of the solder bridge is dirt on the back surface of the screen 58. Therefore, when the solder bridge occurs, it is desirable that the screen 58 be cleaned first.
However, the cause of the occurrence of the solder bridge includes a change in the viscosity and the material of the creamy solder 156. If the occurrence of the solder bridge is not eliminated by cleaning the screen 58, the occurrence of the defect is notified to the operator, and the work is performed. The user checks the printing conditions and the creamy solder 156.

Further, in the above embodiment, when the cream-like solder 156 is detected, the printed circuit board 28 is moved to the downstream side of the screen printing apparatus 10. After printing, the screen 58 is retracted from the printed circuit board 28. Alternatively, the cream-like solder 156 may be detected.

Further, the screen cleaning device removes the creamy solder adhered to the inner peripheral surface of the through hole 62 like the screen cleaning device described in the specification of Japanese Patent Application No. 4-31580 of the present applicant. It may be blown off by compressed air and removed by vacuum.

Further, as described in the specification of Japanese Patent Application No. 4-31580 of the present application, it is possible to partially change the printing pressure in a direction perpendicular to the moving direction of the squeegee. The printing pressure may be changed so that an appropriate printing amount is obtained according to the distribution of the printing amount.

In the above embodiment, the screen 5
8, only a part of the screen 58 is acquired.
The printed result may be inspected by detecting all the cream solder 156 printed on the printed circuit board 28 as well.

Further, the defect cause removing device is not limited to the screen cleaning device 18, the screen positioning and supporting device 36, and the creamy solder replenishing device 172, but may be any device that can automatically remove the cause of printing failure.

In addition, without departing from the scope of the claims, the present invention can be carried out in various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a seal for a screen printing machine according to one embodiment of the present invention.
FIG. 1 is a plan view schematically showing a screen printing machine provided with a printing result inspection device .

FIG. 2 is a side view showing a screen printing device and a screen cleaning device of the screen printing machine.

FIG. 3 is a plan view showing a screen positioning support device of the screen printing device.

FIG. 4 is a plan view showing a screen used in the screen printing apparatus.

FIG. 5 is a side sectional view showing a part of the screen.

FIG. 6 is a front sectional view showing a Y-axis direction position setting device of the screen positioning and supporting device.

FIG. 7 is a front view showing an X-axis direction pressing device of the screen positioning and supporting device.

FIG. 8 is a front sectional view showing a squeegee unit of the screen printing apparatus.

FIG. 9 is a diagram illustrating the principle of a laser displacement sensor that detects creamy solder printed on a printed circuit board.

FIG. 10 is a plan view showing the screen cleaning device.

FIG. 11 is a front view of the screen cleaning device.

FIG. 12 is a block diagram of a control device for controlling the screen printing machine.

[Explanation of symbols]

 Reference Signs List 10 screen printing device 28 printed circuit board 38 squeegee device 58 screen 62 through hole 220 laser displacement sensor 232 CCD camera 300 control device

Continuation of the front page (56) References JP-A-2-60748 (JP, A) JP-A-6-91846 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41F 15 / 00-15/46 B41F 33/14

Claims (7)

(57) [Claims] A squeegee moves on a screen.
Through multiple through holes formed in the screen
Screen printing machine that prints the printing agent on the printing plate
A method for inspecting a print result, At least a part of the plurality of through holes of the screen
Image to obtain an image of a part including objects in a two-dimensional view
The acquisition process, Based on the image acquired in the planar image acquisition step,
A reference data creation process for creating reference data; At least in the step of obtaining the planar view image of the screen,
Through the through-hole that has acquired a planar view to the printing plate
A print status acquisition process that acquires the print status of the printed printing agent
About The printing state of the printing agent obtained in the printing state obtaining step
Inspect the print result by comparing the status with the reference data
A screen including a printing result inspection step
Printing result inspection method for printing press. 2. The method according to claim 1, wherein the reference data creating step includes the step of:
The printing position, printing area, and printing amount of the printing agent printed on the board
Creating the reference data for at least one
The screen mark according to claim 1, comprising:
Printing result inspection method for printing press. 3. The method according to claim 1, wherein the step of obtaining the plan view image includes the step of:
Acquisition of a planar view image and the printing state acquisition step
At least one of acquiring the printing state of the printing agent is performed by the imaging device.
2. The method according to claim 1, wherein the imaging is performed based on an image taken by the device.
Or the printing result inspection method for screen printing machines described in 2.
Law. 4. An imaging device according to claim 1, wherein
Devices in a plane parallel to the screen.
On an XY coordinate plane defined by orthogonal X axis and Y axis
Moving to a desired position.
4. The printing result inspection method for a screen printing machine according to 3. 5. A printing result inspection method for the screen printing machine.
Inspection by the screen printing machine
Performing at a different position from the position where printing on the board is performed
The method according to any one of claims 1 to 4, wherein
Screen sign Printing result inspection method for printing press. 6. A squeegee moving on a screen.
Through multiple through holes formed in the screen
Screen printing machine that prints the printing agent on the printing plate
An apparatus for inspecting a print result, At least a part of the plurality of through holes of the screen
Image to obtain an image of a part including objects in a two-dimensional view
Acquisition means; Based on the image acquired by the plane view image acquisition means
Reference data creation means for creating reference data; By the screen printing machine, at least the screen
A planar view image is acquired by the planar view image acquiring means.
Of the printing agent printed on the printing plate through the through hole
A printing state acquisition unit for acquiring a printing state; The printing state of the printing agent obtained by the printing state obtaining means
Inspect the print result by comparing the status with the reference data
A screen including print result inspection means
Printing result inspection device for printing press. 7. The screen printing machine, wherein the screen printing machine includes:
At least the plane view image acquisition unit and the printing state acquisition unit
One another in a plane parallel to the screen.
XY coordinates defined by the X and Y axes that are orthogonal to each other
Including an XY moving device that moves to any position in the plane
The printing for a screen printing machine according to claim 6, characterized in that:
Result inspection device.