JP3991795B2 - Screen printing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screen printer used for supplying an electronic material paste such as cream solder to an electronic circuit board, and in particular, in the case where printing is performed using screens (masks) having different plate making standards using the same printer. The present invention relates to a screen printer suitable for shortening the working time and obtaining good printing performance.
[0002]
[Prior art]
As conventional screen printers, there are those disclosed in JP-A-10-157060 and JP-A-2000-27289.
[0003]
Japanese Patent Application Laid-Open No. 10-157060 discloses a mask having a pattern hole suitable for electrode arrangement, positioning means for positioning the substrate directly under the mask, and sliding on the mask to the electrode of the substrate through the pattern hole. A squeegee for printing cream solder, a moving means for moving the squeegee, a control unit for controlling the operation of the positioning means and the moving means based on predetermined printing conditions, and inspecting the print quality of the cream solder after printing A printing state detection unit that performs screen printing while correcting printing conditions based on the print quality detected by the printing state detection unit, and the control unit has two modes, a quality priority mode and a production priority mode. In the quality priority mode, the condition that the quality is improved at the expense of the tact time. And to select the shorter becomes the printing condition apparatus is disclosed.
[0004]
In Japanese Patent Laid-Open No. 2000-272089, in order to correct a printing position shift, a printing material provided with a position recognition reference mark is placed on a printing table, and printing is performed on the printing material by printing plate making. At the same time, a print position recognition mark is printed in the vicinity of the position recognition reference mark, and the amount of displacement of the position recognition mark is measured by image processing while capturing each mark within the same field of view of the imaging camera. An apparatus is disclosed in which a printing table is corrected in the X, Y, and θ directions in accordance with the amount of misalignment, and the position of the substrate to be printed is adjusted with respect to the printing plate making.
[0005]
[Problems to be solved by the invention]
By the way, in the above prior art, there is only one type of substrate to be printed, and therefore, a mask to be used has a single pattern. By the way, recently, there are many kinds of printed materials, and it is necessary to exchange masks and the like according to the kinds. For this reason, when using plate frames with different plate making standards, it is necessary to adjust the position of the plate frame according to the substrate width, and much work time is spent when changing the printing press. In addition, it may take a long time to set the plate frame even when the size of the plate frame is different.
[0006]
In addition, an electronic circuit board to which an electronic material paste such as cream solder is supplied by a screen printing machine is generally composed of a composite material, and may be warped rather than a uniform flat plate. When printing an electronic material paste on such a substrate, for example, in a medium-high substrate, the printing pressure at the center is higher than that at the periphery. However, since the printing pressure is low, problems such as insufficient filling of the paste into the mask opening may occur.
[0007]
In order to reduce such printing defects, special warp correction means are used in the screen printer. A typical means is a substrate suction jig. The substrate suction jig is provided on the printing table and corrects the warpage of the substrate by sucking the substrate with a vacuum suction force. In order to provide a substrate suction jig in a printing machine, it is necessary to add a porous suction plate, a solenoid valve, a vacuum pump, a vacuum pipe, etc., resulting in a problem that the printing machine becomes complicated and expensive. .
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide a screen printing machine capable of changing the plate frame in a short time and capable of printing with high accuracy even when the substrate conveyance standard and the plate making standard are different or when the plate frame size is changed.
[0009]
Furthermore, the present invention corrects the warping of the substrate simply and effectively without using a special jig such as a substrate suction jig, and evenly prints evenly on the warped substrate. An object of the present invention is to provide a screen printer provided with means for obtaining the above.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the screen printing machine of the present invention has a plate frame stopper that can be vertically expanded and contracted attached to a squeegee head, a conveyance standard of the printing machine, a mask plate making standard, a plate frame size, and a substrate size. Etc. to the control device of the screen printing machine, the control device calculates the appropriate position of the plate frame, and based on the result, the contact surface of the plate frame stopper attached to the squeegee head is the plate frame. The squeegee head is automatically moved to a position coinciding with the rear end surface, and then the plate frame stopper is extended to a height at which it contacts the rear end surface of the plate frame, and the operator contacts the rear end surface of the plate frame with the plate frame stopper. This is characterized in that the position of the plate frame is determined.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic view showing the configuration of the screen printing machine of the present invention. In FIG. 1, a squeegee head 3 is provided which is guided by a pair of guide rails 2 provided on the upper part of a main body frame 1 and moves in the front-rear direction of the figure. The squeegee head 3 is configured to move by a ball screw 4 that is rotated by a drive motor 4M attached to the main body frame 1 side. The squeegee head 3 is equipped with a squeegee 5 that moves up and down by a squeegee lifting cylinder 6. Further, the main body frame 1 is provided with a plate frame receiver 7, and a plate frame 9 with a screen (mask) 8 having a printing pattern as an opening is set on the plate frame receiver 7. Yes. The plate frame 9 is fixed to the plate frame receiver 7 by a plate frame clamp 7a during printing.
[0012]
A printing table 10 is provided on the main body so as to be movable in the XYθ and Z directions by an XYθ table 11 and a table lifting mechanism (not shown). A substrate receiving conveyor 12 is provided on the upper surface of the printing table 10. After the substrate 15 carried by the substrate carry-in conveyor 13 is received by the conveyor 12 and stopped at a predetermined position, the printing table 10 is raised, the substrate 15 is placed on the printing table, and positioned. The printing table 10 is raised and brought into contact with the mask 8 to execute printing. When printing is completed, the printing table 10 is lowered, the substrate 15 is transferred to the substrate receiving conveyor 12, and then the substrate is transferred out of the apparatus using the substrate discharging conveyor 14.
[0013]
Further, between the printing table 10 and the mask 8, the CCD camera 16 for imaging the alignment marks provided on the mask 8 and the substrate 15 and recognizing the respective positions can move in the XY directions. It is provided. When the positional deviation amount is measured by the CCD camera 16, the XYθ table is driven to correct the deviation. Description of the drive mechanism and operation of the CCD camera is omitted.
[0014]
Further, in the present embodiment, a squeegee head 3 is provided with a plate frame stopper 30. The plate frame stopper 30 includes a pneumatic cylinder and a rod 30a that expands and contracts vertically by the driving force of the pneumatic cylinder.
[0015]
Next, the conveyance reference and the plate making reference will be described with reference to the top views of the screen printing machine shown in FIGS.
[0016]
The conveyance width of the carry-in conveyor 13, the substrate receiving conveyor 12, and the substrate carry-out conveyor 14 used for conveying the substrate 15 can be adjusted according to the width dimension of the substrate 15. Here, in adjusting the width of each board conveyor, the conveyor width is adjusted by fixing the conveyor rail on one side and moving the other conveyor rail, and opening and closing both conveyor rails by the same amount. There is a way to do it. When the rail on the front side of the printing press is fixed in the former method, it is called a front reference, and the latter method is called a center reference. The plate making standard differs depending on these conveyance standards. FIG. 2 shows an example when the transport reference is the front reference.
[0017]
In FIG. 2, a printing pattern 21 is made as an opening on the mask 8 attached to the plate frame 9. The plate frame 9 is set on the plate frame receiver 7 so that the substrate 15 is carried and fixed almost directly below the pattern 21. In FIG. 2, b shown by a broken line is a fixed side rail of the board receiving conveyor, and m ₁ shows a movable side rail end face when printing on a board having a board width W ₁ . In the figure, m ₂ indicated by a two-dot chain line is the position of the end surface of the movable rail when printing on the substrate having the substrate width W ₂ , and 22 is the arrangement of the printing pattern at that time. That is, it is not necessary to change the position of the plate frame 9 according to the width of the substrate 15 if the printing pattern is made so that the front end thereof coincides with the end surface position of the fixed rail b. L in FIG. 2 is a symbol representing the distance between b and the plate frame center c.
[0018]
FIG. 3 is a diagram for explaining center-based plate making. In the printing machine of the center reference, the end face positions of the conveyor rail when printing the board having the board width W ₁ are m ₁ and m ₁ ′ indicated by broken lines, and 23 is a printing pattern at that time. The position of the end face of the conveyor rail when printing substrates of a substrate width W ₂ is m ₂ and m _{2 'shown} by the two-dot chain line, 22 is an arrangement of the print pattern at that time. That is, if the printing pattern is made so that its center line coincides with the center line c of the plate frame, the position of the plate frame 9 does not need to be changed depending on the width of the substrate 15.
[0019]
By the way, when the plate frame 9 provided with the mask 8 made with the center reference is printed using a near-standard printing machine, the position of the plate frame 9 needs to be changed according to the dimensions of the substrate 15. FIG. 4 is a diagram for explaining the plate frame position when the printing pattern 23 in the case of the substrate width W ₁ is made on the basis of the center and is used in the near-standard printing machine. The symbols used in FIG. 4 are the same as those used in FIGS. Here, the two-dot chain line shows the position when the plate frame made with the center reference is placed on the center reference printing machine, and the solid line shows the plate frame made with the center reference. This is the position when placed on the printing press. The difference delta position of both _{Δ = L-W 1/2} ( Equation 1)
Thus, the position of the plate frame 9 needs to be changed depending on the substrate width W.
In this way, if different standard plate frames 9 are used, alignment is required each time.
[0020]
Therefore, in this embodiment, in order to perform this alignment easily, alignment is performed using the plate frame stopper 30. FIG. 5 shows a top view of the screen printing machine of the present invention. In this example, the transport standard is the near standard, and the plate making standard of the set plate frame 9 is also the near standard. As shown in FIG. 5, the squeegee head 3 is configured to move substantially at right angles to the conveyors for substrate loading, substrate transfer, and substrate unloading. Further, two plate frame stoppers 30 are provided on one end face side of the squeegee head 3 and are configured to move together with the squeegee head 3. The squeegee head always returns to the origin position (starting start position) when one series of printing is completed. For this reason, when the plate frame is exchanged, it is possible to determine how much the squeegee head is moved from the origin position so that the plate frame stopper comes into contact with the rear end of the plate frame.
[0021]
FIG. 6 is an AA arrow view of FIG. The rod 30a of the plate frame stopper 30 is in an extended state, and the rear end surface 9S of the plate frame 9 is in contact with the rod 30a of the plate frame stopper 30. As described above, since the plate making reference and the transport reference are both the front reference, the plate frame 9 is moved to the plate making reference position by the rod 30a of the plate frame stopper 30. Generally, when the plate making standard is the near standard and the transport standard is also the near standard, the position of the front side of the plate frame 9 is uniquely determined. Therefore, the stop position of the plate frame stopper is obtained in advance, the movement of the plate frame stopper is controlled from the origin position to that position, the plate frame stopper 30 is stopped at the predetermined position with the rod 30a extended, and The plate frame 9 can be positioned by carrying it in from the rear end side of the plate frame 9 and moving it until it hits the rod 30a of the plate frame stopper 30. In the above embodiment, the plate frame stopper 30 is described by positioning the rear end portion of the plate frame. However, the front end portion of the plate frame can be naturally positioned.
[0022]
As another method for positioning the plate frame 9, although not shown, there is a method in which a front end stopper or a rear end stopper provided with a drive mechanism is provided at the front or rear portion of the plate frame receiver on the apparatus main body side. is there. In this case, a stopper that can move in the horizontal direction (front-rear direction) is provided at the front end of the plate frame receiver, and the position of the stopper can be changed according to the inputted data of the size of the plate frame and the substrate. For example, the variable stopper is provided at the front end, and after the position is adjusted according to the size of the substrate or the like, the plate frame is placed on the plate frame support and the substrate is pushed forward by the plate frame stopper 30 described above, There is also a method of positioning the plate frame by pressing it against the front end stopper. In this way, it is also possible to automatically position the plate frame using the previous plate frame stopper 30 as the plate frame pressing member. The stopper of the positioning mechanism may have a configuration in which the positioning pin protrudes from the plate frame receiving portion. Further, the plate frame front end side or rear end side of the plate frame clamps 7a provided on the plate frame receiver 7 provided on the apparatus main body side can also be used as a plate frame front end stopper. is there.
[0023]
As described above, even if the size of the printed substrate and the size of the plate frame are changed by providing the plate frame stopper, the position of the plate frame can be changed in accordance with the substrate in a short time. The printing time can be shortened during printing.
[0024]
FIG. 7 is a flowchart showing a procedure for setting up a plate frame in the screen printing machine of the present invention. Hereinafter, in the procedure of FIG. 7, a plate frame stopper is provided in the squeegee head unit, and the position of the plate frame stopper is determined based on the substrate size, the size of the plate frame, the conveyance reference, and the data of the plate frame reference. In addition, after stopping the plate frame stopper at that position, the method of carrying in and setting the plate frame from the front side of the apparatus is shown.
[0025]
First, when the plate frame setup operation is started (100), the operation mode of the printing press is selected as the single-action operation setup mode (101). Next, the plate frame clamp 7a is released (102), and the plate frame 9 set on the plate frame receiver 7 is removed (103).
[0026]
Thereafter, the plate making standard of the mask 8 to be newly used, the size of the plate frame 9, and the size of the substrate 15 are input to the control device of the screen printing machine (104). In general, the conveyance reference of the printing press is a condition specific to the printing press and is set in the control device in advance, and therefore need not be input again. In this state, the control device calculates the stop position of the plate frame stopper 30 from the conveyance reference and the plate making reference, and outputs a signal of the position where the squeegee head 3 should move to the squeegee drive motor 4M.
[0027]
Next, when the plate frame setup start button is pressed, the squeegee head 3 executes a positioning operation based on a signal from the control device (105). Thereafter, the rod 30a of the plate frame stopper 30 extends (106).
After confirming this state, the operator places a new plate frame 9 on the plate frame receiver 7, and abuts the rear end surface 9S of the plate frame 9 so as to contact the rod 30a of the plate frame stopper 30 (107). By this operation, the position of the plate frame 9 becomes an appropriate state. This abutting operation may be performed automatically by the plate frame carry-in device or manually by the operator.
[0028]
Thereafter, the plate frame 9 is fixed to the plate frame holder 7 by the plate frame clamp 7a (108), the rod 30a of the plate frame stopper 30 is contracted (109), and the squeegee 3 is returned to a fixed position (110). The setup work for the frame 9 ends (111).
[0029]
Although only the basic procedure of the present invention is shown in FIG. 7, it is confirmed by an image that the plate frame 9 is properly set by operating the mark recognition camera 16 after the procedure 107. Of course, it is not contrary to the gist of the present invention to add an operation such as moving the squeegee head 3 to align the plate frame 9 at an appropriate position when the recognition mark is not in the field of view of the camera 16. Yes.
[0030]
By the way, in the above embodiment, the explanation has been made on the assumption that the substrate carried in is flat without warping, but actually the substrate may be warped, and this warping must be corrected when printing the paste. If it is, accurate printing cannot be performed. Therefore, a configuration for correcting the substrate will be described with reference to the drawings. In this embodiment, a substrate correction roller is provided in the squeegee portion of the apparatus shown in FIG. FIG. 8 shows the outline of the configuration of the squeegee unit. The squeegee head 3 is provided with two squeegees 5 that can be moved up and down according to the traveling direction. As shown in FIG. 8, a squeegee lifting cylinder 6, which is a vertical drive mechanism that lowers the squeegee 5 on one side to a position for pressing the surface of the mask 8 against the substrate surface in accordance with the traveling direction (the arrow direction in FIG. 6A). In addition, a correction roller 51 that is rotatable in parallel with the squeegee 6 and applies a predetermined pressing force is provided so as to be substantially on the same surface as the surface of the squeegee 5 that contacts the mask 8 surface.
[0031]
FIG. 9 shows a view of the squeegee portion viewed from the side.
[0032]
In FIG. 9, roller holding metal fittings 52 are attached to both ends of the squeegee 5 by screws 53. The roller holding metal 52 is provided with a long hole 54 for holding the substrate warpage correction roller 51 so as to be rotatable and vertically movable. The long hole 54 supports shafts 55 at both ends of the substrate warpage correction roller 51. . Here, the substrate warp correction roller 51 is supported such that its axis is substantially parallel to the paste scraping edge 5E of the squeegee 5.
[0033]
FIG. 10 is a view for explaining the operation of the warped substrate and the correction roller.
[0034]
In FIG. 10, the substrate 15 carried on the printing table 10 may be warped at the center. When printing is performed on such a substrate 15 with a conventional printing machine that does not have the substrate warp correction roller 51, the pressure (printing pressure) acting on the substrate 15 from the squeegee 15 through the mask 8 is high in the center of the substrate. The periphery is lowered. For this reason, the amount of paste filled in the openings of the mask 8 becomes non-uniform, resulting in non-uniform printing results at the central and peripheral portions of the substrate.
[0035]
On the other hand, when the squeegee head 3 provided with the substrate warp correction roller 51 of the present invention is used, the warpage of the substrate 15 is corrected by the weight of the substrate warpage correction roller 51 as the squeegee 5 moves. At this time, since the substrate warp correction roller 51 is supported by the elongated hole 54 so as to be movable in the vertical direction as shown in FIG. 9, the reaction force of the substrate warpage correction roller 51 does not act on the squeegee 5. The pressure (printing pressure) acting on the substrate 15 from the squeegee 5 through the mask 8 becomes uniform over the entire surface of the substrate. Therefore, the amount of paste filled in the opening of the mask 8 becomes uniform, and a uniform printing result can be obtained over the entire surface of the substrate substrate.
[0036]
【The invention's effect】
By using the present invention, it is possible to change the plate frame in a short time even when the substrate conveyance standard and the plate making standard are different or when changing the size of the plate frame. A screen printer capable of printing can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the configuration of a screen printing machine according to the present invention.
FIG. 2 is a plan view for explaining that a setting position of a plate frame differs depending on a conveyance reference and a plate making reference.
FIG. 3 is a plan view for explaining that a setting position of a plate frame differs depending on a conveyance reference and a plate making reference.
FIG. 4 is a plan view for explaining that a setting position of a plate frame differs depending on a conveyance reference and a plate making reference.
FIG. 5 is a plan view showing the configuration of the screen printing machine of the present invention.
6 is a cross-sectional view taken along the line AA in FIG.
FIG. 7 is a flowchart for explaining a plate frame setup procedure of the screen printing machine according to the present invention.
FIG. 8 is a diagram illustrating a configuration of a squeegee head unit according to the present invention.
FIG. 9 is a view showing a side surface of the squeegee head.
FIG. 10 is a diagram for explaining an operation of correcting substrate deflection.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Main body frame, 3 ... Squeegee head, 5 ... Squeegee, 7 ... Plate frame receiver, 8 ... Mask, 9 ... Plate frame, 10 ... Printing table, 12 ... Substrate receiving conveyor, 13 ... Substrate carrying-in conveyor, 14 ... Substrate carrying out Conveyor, 15 ... substrate, 30 ... plate frame stopper, 51 ... straightening roller, 52 ... roller holding bracket.

Claims (1)

The size of the substrate to be printed and the size of the mask can be varied, the plate frame with the mask attached is attached to the plate frame receiver provided in the apparatus body, and the desired pattern opening is provided on the substrate placed on the table. pressed against the mask in a screen printing machine with a squeegee moving on the mask to print push the paste into the opening,
A stopper made of stretchable pressing member to the squeegee head mounted the squeegee is provided, one a squeegee head moving direction from either the front or rear end of the plate frame receiving unit, while positioned by the stopper the arranged substantially parallel to the paste scraping edge of the squeegee, rotatable about the axis, and wherein the squeegee head, the squeegee deformation of the substrate by separately substrate straightening rollers mounted movably in the vertical direction and A screen printing machine characterized in that it is configured to correct.

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