JP2006264007A - Screen printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screen printing device of a paste which can secure the airtightness of a printing space and thereby, eliminate a paste leakage to the squeegee head side, regardless of the magnitude of crosswise size of a substrate. <P>SOLUTION: In this screen printing device, a cartridge 31 is stored in the upper part 30A of a main body of a squeegee head 13 and the lower part 30B of the main body is formed with perforated plates 32 and 33 sandwiched between the upper part 30A and the lower part 30B. In addition, a horizontal shaft 40 is formed in a printing space 35 between the perforated plate 33 and a mask plate 12, and two right/left partitioning members 41 are fitted freely slidably in the shaft 40. Further, the lower surface of the partitioning member 41 is brought into close contact with the upper surface of the mask plate 12 by adjusting the interval between the partitioning members 41 in accordance with the magnitude of crosswise size of the substrate 6 to be screen-printed, and thereby, a cream solder P in the printing space 35 is prevented from leaking to the squeegee head 13 side by ensuring the airtightness of the printing space 35. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a screen printing apparatus that prints paste such as cream solder or conductive paste on a substrate.

  In an electronic component mounting process, screen printing is used as a method of printing paste such as cream solder or conductive paste on a substrate. In screen printing, a mask plate with pattern holes is set on the substrate according to the print target site (generally, the electrode of the circuit pattern), and paste is applied to the substrate through the pattern holes of the mask plate by squeezing. Is to be printed.

  As a screen printing squeezing method, a method using a sealed squeegee head is known. Unlike normal screen printing, this method uses a squeegee head in which the paste is stored, instead of supplying the paste directly onto the mask plate. In this method, the paste is pushed into the pattern hole of the mask plate by pressing the paste in the squeegee head from above with the paste contact surface provided on the lower surface of the squeegee head in contact with the mask plate. Then, by sliding two front and rear sliding portions (squeegees) provided on the squeegee head on the mask plate, each pattern hole is sequentially filled with paste.

  However, the paste storage container used in the above-described conventional sealed squeegee head is a container manufactured by molding a resin into an elongated box shape, and thus has a high running cost, and remains unused inside. This is a factor that increases the cost of screen printing, such as generation of residual paste that is discarded as it is and waste of paste.

  Therefore, the present applicant has previously proposed a screen printing apparatus capable of supplying paste at a low cost (Patent Document 1). This is a replaceable cartridge (paste container) by forming a paste storage container that stores paste in the squeegee head into a container shape with a flexible resin film open at the bottom. The paste storage container can be manufactured at a low cost.

  FIG. 8 is a cross-sectional view of a squeegee head of a conventional screen printing apparatus, and relates to Patent Document 1. An exchangeable paste storage container (cartridge) 102 for storing the paste P is detachably held inside the frame-type container holding portion 101 of the hermetic squeegee head 100. The paste container 102 is made of the above-described flexible resin film, and its upper surface is pressed downward by a pressure plate 103.

  A receiving part 104 is provided opposite to the container holding part 101, and the end parts of the two upper and lower perforated plates 105, 106 are sandwiched from above and below by both 101, 104. The receiving unit 104 is grounded to the upper surface of the mask plate 108 superimposed on the substrate 107, and the inside is a printing space 109. A horizontal shaft 110 as a rectifying member is disposed inside the lower receiving portion 104 with both ends thereof held by the lower receiving portion 104. Reference numeral 111 denotes a pattern hole opened in the mask plate 108.

By pressurizing the paste container 102 from above with the pressure plate 103, the paste 112 inside the paste container 102 has a large number of holes 112 formed on the entire surface of the porous plates 105 and 106.
, 113 descends and flows to the lower printing space 109, and the squeegee head 100 slides in a direction perpendicular to the paper surface (Y direction), thereby providing two front and rear slides (not shown) provided in front of and behind the squeegee head 100. The paste P is printed on the substrate 107 through the pattern 111 by the contact portion (squeegee).
JP 2004-17515 A

  In FIG. 8, the dimension L in the horizontal direction (X direction) of the substrate 107 varies in size. In the present invention, the sliding (squeegeeing) direction of the sliding contact portion (squeegee) is defined as the front-rear direction (Y direction), and the direction orthogonal thereto is defined as the lateral direction (X direction). FIG. 8 shows a case where screen printing is performed on a substrate 107 having a slightly short lateral dimension L.

  In this case, free portions D of the mask plate 108 where the substrate 107 does not contact are generated on both sides of the mask plate 108. Since the substrate 107 does not come into contact with the free portion D, the mask plate 108 hangs down slightly in the free portion D as shown in the figure. As a result, a slight gap G is generated between the lower receiving portion 104 on the side of the squeegee head 100 and the mask plate 108, and paste leakage occurs on the mask plate 108 from here. The paste P leaked onto the mask plate 108 unnecessarily stains the mask plate 108 and obstructs screen printing. The gap G becomes larger as the lateral dimension L of the substrate 107 is smaller, which adversely affects screen printing.

  Accordingly, the present invention eliminates the above-described conventional problems, ensures the sealing of the printing space regardless of the horizontal dimension of the substrate, and eliminates paste leakage to the side of the squeegee head. The purpose is to provide.

  2. The paste screen printing apparatus according to claim 1, comprising a squeegee head, horizontal moving means for moving the squeegee head horizontally on the mask plate, and lifting means for moving the squeegee head up and down relative to the mask plate. The squeegee head includes a paste storage part for storing paste, a pressurizing means for pressurizing the paste in the paste storage part from above, and a pressure applied by the pressurizing means to flow downward. A printing space in which the paste is brought into contact with the surface of the mask plate through an opening formed on the lower surface and containing the paste, a paste passage member interposed between the paste reservoir and the printing space, and the printing Two opposing front and rear sliding contacts that form front and rear walls in the squeezing direction of the space and that are in sliding contact with the upper surface of the mask plate When, and a partition member defining the lateral width of the printing space is disposed in the lower portion of the paste passing member.

  The paste screen printing apparatus according to claim 2 is the paste screen printing apparatus according to claim 1, wherein a horizontal shaft is provided below the paste passage member, and the partition member is slid laterally on the shaft. Freely provided.

  The paste screen printing apparatus according to claim 3, wherein the paste screen printing apparatus according to claim 2 is provided with a receiving portion facing the paste storage portion below the paste storage portion, and both ends of the shaft. The part was held by this receiving part.

  According to the present invention, the lateral position of the partition member is set in accordance with the size of the lateral dimension of the substrate, thereby defining the lateral width of the printing space, whereby the paste to the side of the squeegee head Leakage can be eliminated.

  Next, embodiments of the present invention will be described with reference to the drawings. 1 is a front view of a screen printing apparatus according to an embodiment of the present invention, FIG. 2 is a side view of the screen printing apparatus according to an embodiment of the present invention, and FIG. 3 is a screen printing apparatus according to an embodiment of the present invention. 4 is a front sectional view of the squeegee head, FIG. 4 is an internal plan view of the squeegee head of the screen printing apparatus in one embodiment of the present invention, and FIG. 5 is a cartridge of the squeegee head of the screen printing apparatus in one embodiment of the present invention. FIG. 6 is an explanatory view of a partition member of the squeegee head of the screen printing apparatus according to the embodiment of the present invention, and FIG. 7 is a plan view of the perforated plate of the screen printing apparatus according to the embodiment of the present invention.

  First, the overall structure of the screen printing apparatus will be described with reference to FIGS. 1 and 2, the substrate positioning unit 1 includes a Y table 2, an X table 3, a θ table 4, a backup unit 5, and the like stacked in order from the bottom. The backup table 5 includes an entire lifting motor 51 of the backup unit 5, a lifting motor 53 of the backup plate 52, and the like, and supports the substrate 6 from below by support pins (not shown) erected on the backup plate 52. To do. The board | substrate 6 is carried in to the guide rail part 8 above the positioning part 1 by the carrying-in part 7, and is positioned in a predetermined position there by the positioning part 1, and screen printing of the paste is made on the upper surface. The substrate 6 for which printing has been completed is carried out to the next step by the carry-out unit 9.

  A screen mask 10 is disposed above the positioning unit 1. The screen mask 10 is configured by mounting a mask plate 12 on a holder 11, and a pattern hole 12 a (FIG. 3) corresponding to a print target portion of a substrate 6 to be printed is opened in the mask plate 12.

  A squeegee head 13 is disposed on the screen mask 10 so as to be movable up and down by a head lifting unit 20. The head lifting / lowering unit 20 includes a cylinder 22 that is erected on a long plate-like base 21, and a squeegee head via a plate-like coupling member 15 at the lower end of the rod 22 a of the cylinder 22. 13 are connected. The squeegee head 13 moves up and down with respect to the mask plate 12 by driving the cylinder 22 to project and retract the rod 22a. Therefore, the head lifting / lowering unit 20 is a lifting / lowering unit that lifts / lowers the squeegee head 13 relative to the mask plate 12.

  In FIG. 1, sliders 23 are mounted on the lower surfaces of both ends of the base portion 21 of the head elevating unit 20, and the sliders 23 slide on guide rails 24 that are horizontally disposed in the Y direction on the upper surface of the standing frame 25. Fits freely. Further, a nut member 26 is coupled to the lower surface of the side portion of the base portion 21, and a feed screw 27 screwed into the nut 26 is rotationally driven by a motor 28 (see also FIG. 2).

  In FIG. 2, by driving the motor 28, the base 21 moves horizontally in the Y direction. Therefore, by driving the motor 28 with the squeegee head 13 lowered, the squeegee head 13 moves horizontally on the mask plate 12 in the Y direction. That is, the motor 28, the feed screw 27, and the nut 26 serve as a horizontal movement unit that moves the squeegee head 13 on the mask plate 12 in the horizontal direction.

As will be described later, the squeegee head 13 is provided with a partition member 41 that defines the width of the printing space in the lateral direction (see FIGS. 3 and 4), and the perforated plates 32 and 33 are opened only at the center. Except for opening the portions 32a and 33a (see FIG. 7), etc., the configuration is the same as that of Patent Document 1. In FIG. 1, the squeegee head 13 is provided with a printing unit 14 that contacts the surface of the mask plate 12 and fills the pattern holes 12 a with cream solder P that is a paste. The printing unit 14 is divided into an upper part 14A and a lower part 14B, and the upper part 14A and the lower part 14B are provided with a main body upper part 30A and a main body lower part 30B which are elongated frame members in the horizontal direction.

  The horizontal direction (X direction) dimensions of the main body upper part 30A and the main body lower part 30B are set to a length that covers the width dimension of the large substrate 6. The main body upper part 30A and the main body lower part 30B are coupled to each other via a hinge part (not shown) in the same manner as in Patent Document 1, so that the main body upper part 30A and the main body lower part 30B can be rotated or separated around the hinge part. Thus, the cartridge 31 (described later) can be exchanged by opening the both.

  As shown in FIGS. 1 to 3, a cartridge 31 as a paste container in which cream solder P is stored is held in the main body upper portion 30 </ b> A in a replaceable manner. The cartridge 31 is an exchangeable paste container in which a film-like material made of a flexible resin is formed into a container shape, and as shown in FIG. 5, a box part 31a as a thin trapezoidal container part and a collar-like outer edge part It consists of 31b, and has a shape in which the lower part is opened in the state of being mounted inside the main body upper part 30A. In FIG. 3, a cartridge 31 is supported from below by two stacked perforated plates 32 and 33 as paste passing members having a large number of apertures 32a and 33a, and has an outer edge 31b and a perforated plate. The outer edge portions 32 and 33 are sandwiched between the main body upper portion 30A and the main body lower portion 30B and are detachably held in the main body upper portion 30A. The main body upper portion 30A and the cartridge 31 mounted in the main body upper portion 30A constitute a paste reservoir.

  As shown in FIGS. 1 to 3, a pressure plate 29 that pressurizes the cream solder P is disposed on the upper surface side of the cartridge 31 held in the main body upper portion 30 </ b> A. The pressure plate 29 is attached to the lower end portion of the rod 16a of the cylinder 16 arranged upside down. When the cylinder 16 is driven and the rod 16a protrudes and retracts, the pressure plate 29 moves the cartridge 31 downward. Press and release the press. By pressing the cartridge 31 with the pressure plate 29 in this way, the cartridge 31 made of a flexible film-like material is easily bent and deformed, and the cream solder P in the cartridge 31 is pressurized and the porous plates 32 and 33 are pressed. It is extruded downward through the opening portions 32a and 33a. Therefore, the cylinder 16 and the pressure plate 29 serve as pressurizing means for pressurizing the cream solder 9.

  The perforated plates 32 and 33 sandwiched between the main body upper portion 30A and the main body lower portion 30B are provided with a large number of opening portions 32a and 33a. As shown in FIG. 5 of Patent Document 1, the aperture is formed in a wide range on the entire surface of the porous plate. The apertures 32a and 33a of the porous plates 32 and 33 are shown in FIG. As shown in FIG. 4, the central portion K is formed only in the vicinity of the central portion K in the lateral direction (X direction), and is not formed on both side portions. That is, both side portions of the perforated plates 32 and 33 are blind portions S in which the opening portions 32a and 33a are not formed, and the reason will be described later. As described above, the main body upper portion 30A serves as a container holding portion that houses the cartridge 31, and the main body lower portion 30B serves as a receiving portion that faces the container holding portion 30A.

In FIG. 2, two sliding contact portions (squeegees) 36A and 36B opposite to each other in the Y direction (squeezing direction) are obliquely provided on the bottom portion of the lower body portion 30B with a downward slope toward the inside. The inside is a printing space 35 filled with cream solder P, and the perforated plates 32 and 33 are interposed between the cartridge 31 and the printing space 35. The sliding contact portions 36 </ b> A and 36 </ b> B form front and rear walls of the printing space 35, and the lower end portions of the sliding contact portions 36 </ b> A and 36 </ b> B are in contact with the surface of the mask plate 12 in a state where the squeegee head 13 is lowered. Then, the pressurized cream solder P is accommodated in the printing space 35, and the cream solder P is applied to the mask plate 12 through an opening formed on the lower surface (an opening between the sliding contact portion 36A and the sliding contact portion 36B). Touch the surface. During the printing operation, the sliding contact portions 36A and 36B slide on the mask plate 12 by the movement of the squeegee head 13 in the front-rear direction, and perform squeezing that scrapes the cream solder P in the printing space 35.

  1 to 4 and 6, a shaft 40 is provided in the printing space 35 below the perforated plates 32 and 33. The shaft 40 is horizontal, and both end portions in the lateral direction are held by being coupled to the main body lower portion 30B. Two partition members 41 are mounted on the shaft 40 on the left and right sides. The partition member 41 is slid in the lateral direction (X direction) along the shaft 40 to adjust its mounting position, that is, the distance W (W1, W2) between the two, thereby defining the lateral width of the printing space 35. (Refer to the partition member 41 indicated by an arrow a and a chain line in FIG. 6). That is, in FIG. 6, the interval W between the partition members 41 is changed to the intervals W1 and W2 corresponding to the lateral dimensions L1 and L2 of the substrate 6. The shaft 40 also exerts the rectifying action of the cream solder P pushed out from the perforated plates 32 and 33 to the lower printing space 35.

  As shown in FIG. 3, the upper surface of the partition member 41 is in contact with the lower surface of the porous plate 33, and the squeegee head 13 is lowered so that the sliding contact portions 36 </ b> A and 36 </ b> B are grounded on the mask plate 12. The lower surface of 41 is grounded to the upper surface of the mask plate 12 to form a printing space 35 surrounded by the sliding contact portions 36A and 36B and the left and right partition members 41. The partition member 41 is preferably formed of an elastic body so as to be in close contact with the lower surface of the porous plate 33 and the upper surface of the mask plate 12.

  As shown in FIG. 7, the opening portions 32a and 33a are not opened on the entire surface of the perforated plates 32 and 33, but are concentrated in the central portion K as shown by the chain line in FIG. When the horizontal dimension of the substrate 6 is small and the gap of the partition member 41 is correspondingly reduced (see W2), the paste P in the cartridge 31 does not leak downward from the side (outside) of the partition member 41. It is for doing so. That is, the distribution width K of the opening portions 32a and 33a is prepared in advance so that a plurality of different opening sizes can be prepared and can be exchanged according to the width (lateral size) of the substrate 6 to be printed. Of course, when the lateral dimension of the substrate is large, the substrate may be replaced with a perforated plate having openings on the entire surface.

  Next, the screen printing operation will be described. In screen printing, as shown in FIG. 3, the squeegee head 13 is lowered to bring the sliding contact portions 36 </ b> A and 36 </ b> B and the partition member 41 into contact with the upper surface of the mask plate 12. Then, the cartridge 31 is pressed from above by the pressure plate 29. As a result, the cream solder P is pushed out from the cartridge 31 into the lower printing space 35 through the openings 32a and 33a. Therefore, the squeegee head 13 is slid on the mask plate 12. As a result, the cream solder P is rolled by the sliding contact portions 36A and 36B in the printing space 35, thereby causing the rolling flow of the cream solder P, and the cream solder P sequentially into the pattern holes 12a by the sliding contact portions 36A and 36B. P is filled.

  In FIG. 3, the horizontal position of the partition member 41 is adjusted and set according to the horizontal dimension of the substrate 6, and the two left and right partition members 41 are positioned directly above both sides of the substrate 6. The upper surface of the partition member 41 is firmly in contact with the lower surface of the porous plate 33, and the lower surface thereof is firmly in contact with the upper surface of the mask plate 12, so that the gap G shown in FIG. Therefore, the width of the printing space 35 in the lateral direction is defined by the partition member 41, and the sealing property of the printing space 35 is sufficiently secured, so that the cream solder P does not leak to both sides of the squeegee head 13. As described with reference to FIG. 6, by adjusting and setting the position of the partition member 41 according to the horizontal dimension of the substrate 6, the generation of the gap G can be eliminated regardless of the size of the substrate. The sealing of the printing space can be secured. The cream solder P in the cartridge 31 is consumed by repeatedly executing the squeezing operation described above. Finally, if the cartridge 31 is crushed by the pressure plate 21 and the cream solder P is consumed, the upper part 30A of the main body is consumed. The main body lower part 30B is separated and the cartridge 31 is replaced.

  What is necessary is just to set the partition member 41 in the position which can prevent that the clearance gap G generate | occur | produces in the side of the printing space 35 in short. Therefore, as shown in FIG. 3, the partition member 41 does not have to be directly above both sides of the substrate 6, and even if the position is slightly deviated laterally from directly above, the position where the gap G can be prevented from being generated. If it is. In the present embodiment, the partition member 41 is slidably mounted on the shaft 40 to adjust its position. However, in FIG. 6, the left and right partition members 41 are fixed to the shaft 40, and the left and right partition members 41 are A plurality of types of shafts 40 with different intervals W between the partition members 41 may be prepared, and the positions of the partition members may be changed and set by exchanging the shafts 40 according to the size of the lateral dimension of the substrate 6. . In this case, only the shaft 40 to which the partition member 41 is fixed may be attached to and detached from the main body lower portion 30B, or the main body lower portion 30B to which the shaft 40 is attached may be replaced.

  According to the present invention, the horizontal position of the partition member is set corresponding to the size of the horizontal dimension of the substrate, and thereby the horizontal width of the printing space is defined, so that the mask plate hangs downward. Paste leakage to the side of the squeegee head due to the occurrence of gaps caused by descending can be eliminated, stable screen printing can be performed, and it is particularly useful as a screen printing apparatus for printing cream solder on a substrate.

The front view of the screen printing apparatus in one embodiment of this invention The side view of the screen printing apparatus in one embodiment of this invention Front sectional view of a squeegee head of a screen printing apparatus according to an embodiment of the present invention The internal top view of the squeegee head of the screen printing apparatus in one embodiment of this invention The perspective view of the cartridge of the squeegee head of the screen printing apparatus in one embodiment of this invention Explanatory drawing of the partition member of the squeegee head of the screen printing apparatus in one embodiment of this invention The top view of the perforated plate of the screen printing apparatus in one embodiment of this invention Sectional view of a squeegee head of a conventional screen printing apparatus

Explanation of symbols

6 Substrate 12 Mask plate 12a Pattern hole 13 Squeegee head 16 Cylinder 20 Head lifting part (lifting means)
29 Pressure plate 30A Upper part of main body 30B Lower part of main body 31 Cartridge 32, 33 Perforated plate (paste passage member)
35 Printing space 36A, 36B Sliding part 40 Shaft 41 Partition member P Cream solder (paste)

Claims (3)

A paste screen printing apparatus comprising a squeegee head, horizontal moving means for moving the squeegee head horizontally on the mask plate, and lifting means for moving the squeegee head up and down relative to the mask plate,
The squeegee head includes a pace and a storage part for storing the paste, a pressurizing means for pressurizing the paste in the paste storage part from above, and a paste that is pressed by the pressurizing means and flows downward, A printing space in which the paste contacts the surface of the mask plate through the formed opening, a paste passage member interposed between the paste reservoir and the printing space, and front and rear of the printing space in the squeezing direction Two opposing sliding contact portions that form a wall and slidably contact with the upper surface of the mask plate, and a partition member that is disposed under the paste passage member and defines a lateral width of the printing space. A paste screen printing apparatus characterized by the above.   2. The paste screen printing apparatus according to claim 1, wherein a horizontal shaft is provided below the paste passage member, and the partition member is slidably provided on the shaft in a lateral direction. 3. The paste screen printing apparatus according to claim 2, wherein a lower receiving portion is provided below the paste storage portion so as to face the paste storage portion, and both end portions of the shaft are held by the lower receiving portion.

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