JP3610557B2 - Screen printing device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a screen printing apparatus for printing a viscous printing material through a screen plate having a plurality of holes having a predetermined print pattern on a substrate, and in particular, printing of creamy solder on a printed circuit board. The present invention relates to a screen printing apparatus suitable for the above.
[0002]
[Prior art]
The bottom portion includes a pair of front and rear spatula portions that come into contact with the upper surface of the screen plate, and an elongated supply port that is positioned between the pair of spatula portions and configured to be openable and closable. A housing with a chamber for storing the viscous printing material dispensed on the screen plate through the mouth, and the supply port is closed when not printing, is opened only during each printing, and is kept open. The pair of spatula portions contact the upper surface of the screen plate only when the housing is advanced for printing, and the supply port opening / closing mechanism operates to Among the pair of spatula portions, a screen printing apparatus including a squeegee device configured such that the rear spatula portion functions as a squeegee is disclosed in Japanese Patent Application No. 2-41913. Is disclosed in JP), it is already known. When this type of screen printing apparatus mounts a chip-like electronic component on a printed circuit board, the cream-like solder required to solder the electronic component to the conductor pattern on the substrate prior to the mounting operation. In other words, it was developed as an apparatus for printing creamy solder paste by kneading solder alloy powder and high-viscosity liquid flux through a screen plate, and kneading the solder paste stored in the chamber A rotating roller having both a function of applying a discharge pressure to the solder paste is disposed in the chamber, and the built-in solder paste is automatically supplied onto the screen plate while being automatically supplied onto the printed circuit board. It is possible to screen-print on the conductor pattern of the solder paste before soldering. Compared to the conventional one (see Japanese Patent Publication No. 1-19275, for example) that is preliminarily placed on a screen plate and then screen printed by sliding the squeegee back and forth on the screen plate. Thus, it has become possible to further improve the efficiency and accuracy of printing work.
[0003]
[Problems to be solved by the invention]
In screen printing, the squeegee slides linearly in contact with the upper surface of the screen plate, and the sliding force causes the viscous printing material to be forced into the holes of the screen plate, and prints on the substrate through the holes. Therefore, in order to improve the printing work efficiency and printing accuracy, it is generally required to prevent changes in the viscosity of the printing material and fluctuations in the supply amount at each printing. In the case of a high-viscosity solder paste that is screen-printed on a printed circuit board, in addition to the above requirements, the printing pressure on the screen plate of the squeegee, that is, the optimization of the contact surface pressure is highly accurate.・ It is particularly required as an important matter from the viewpoint of realizing high-density printing.
[0004]
Among solder pastes for screen printing on printed circuit boards currently marketed, a solder alloy powder having a melting point of about 63% Sn and 37% Pb and a high-viscosity liquid flux are kneaded to obtain a flux content. The one with about 9.3% is widely used. Such commercially available solder pastes are sold in sealed tubes. However, after the tube is opened and taken out, it touches the outside air, so the touched part is cured by volatilization or oxidation of the flux components. , Easy to change viscosity. If the solder paste having such a viscosity change is used for screen printing as it is, solder particles having an appropriate flux and a mass of solder particles having little flux or a reduced amount of flux are used. As a result, the printing condition is not uniform and high-precision printing is not possible, and the defective part may close the hole of the screen and cause damage to the squeegee and / or the screen. Become. In order to avoid the occurrence of such an adverse change in the viscosity of the solder paste, the solder paste must be exposed to the open air as much as possible after the tube is opened and the solder paste is taken out. The previous printing method in which solder paste is put on the screen in advance before printing work and screen printing is performed does not match this requirement, and frequent solder paste requiring manual labor is required. Kneading work was indispensable. In the above-mentioned prior application filed by the applicant (Japanese Patent Application No. 2-419135), solder paste is accommodated in a chamber of a closed housing, and the chamber Since the solder paste contained inside is kneaded by the rotating roller, it is possible to reduce the occurrence of viscosity change of the solder paste without requiring manual work for the kneading work. It became.
[0005]
However, in the conventionally known screen printing apparatuses, including those disclosed in the prior application filed by the applicant, an appropriate pressure for appropriately adjusting the printing pressure, that is, the contact surface pressure as necessary. For example, the printing pressure depends on the degree of viscosity due to the difference in the type of printing material, the size of the holes in the screen plate, the degree of deflection or deformation of the screen plate or squeegee during printing, etc. There is an inconvenience or disadvantage that it cannot be adjusted properly.
[0006]
In screen printing, the contact between the squeegee and the screen plate is mechanically repelled, so if the printing pressure is too strong, the squeegee and / or the screen plate will wear out quickly. This tends to be impossible, and as a result, one or both of them are frequently required to be replaced with new ones, which is not only uneconomical but also reduces the efficiency of the printing operation. In particular, when the printing material is a solder paste, it contains a lot of hard and fine solder particles, and these solder particles perform a rubbing action like a file during printing. Wear is even more intense and premature. On the other hand, if the printing pressure is too weak, the contact surface accuracy or adhesion of the squeegee to the screen plate will be poor, and the forced input of the printing material to the holes in the screen plate will be weak, or the lower edge of the squeegee and the screen plate A slight gap is formed between the upper surface and the printing material leaks from the gap, and an inconvenient situation is likely to occur as a residue on the screen plate. When the printing material to be used is a solder paste as a highly viscous printing material, the solder particles and the flux that are the composition components are separated from each other during the movement of the squeegee, and a large amount of flux is released from the gap. On the other hand, the solder particles with insufficient flux are packed together into the holes of the screen plate, causing so-called clogging, resulting in an unprintable state and less printing accuracy. Absent. If the printing pressure is too weak, the above-described phenomenon occurs. Therefore, high-precision and high-density screen printing using a screen plate having fine holes is impossible.
[0007]
The present invention has been made in view of the problems of the conventional screen printing apparatus as described above, and at the same time possesses the above-described advantages, and does not have the above-described disadvantages or inconveniences. In addition, a screen printing device that can be used for screen printing of solder paste on printed circuit boards, which can achieve higher efficiency in printing operations, significantly improved printing accuracy, and higher printing density, etc. is provided. Its main purpose is to do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object of the present invention, a screen printing apparatus according to the present invention has a pair of front and rear blades in contact with the upper surface of the screen plate at the bottom, and is positioned between the pair of blades so as to be openable and closable. A horizontally long supply port, and a housing including a chamber for storing a viscous printing material dispensed on the screen plate through the supply port, and the supply port being closed when not printing. And a supply port opening / closing mechanism that opens only at the time of each printing and operates so as to maintain the opening state, and the pair of blades is only when the housing is advanced for printing. A squeegee device configured to come into contact with the upper surface of the screen plate and the rear blade of the pair of blades functions as a squeegee blade. The rear wall of the housing is attached to the upper fixed wall portion and the fixed wall portion so as to be swingable in the front-rear direction and vertically movable about a straight line extending in the lateral direction as a swing shaft. A lower movable wall portion operatively connected to the supply port opening / closing mechanism, the rear blade being fixed to the movable wall portion, and the movable wall portion being moved in the front-rear direction by the supply port opening / closing mechanism. Accordingly, the rear blade comes into contact with and separates from the front blade to open and close the supply port, and the movable wall portion is formed on each outer side of the left and right side walls of the housing. The screen plate of the rear blade as the squeegee blade is provided with adjusting means capable of finely adjusting the height of the movable blade, and finely adjusting the height of the movable wall portion through the adjusting means. Is characterized in that is configured as a surface-approaching pressure can be finely adjusted against.
[0009]
For advantageous embodiments of the invention, reference is made to the claims 2-12.
[0010]
[Action]
In the screen printing apparatus according to the present invention, the height of the movable wall portion is finely adjusted by operating the adjusting means capable of finely adjusting the height of the movable wall portion provided on each of the left and right side walls of the housing. By doing so, the contact pressure on the screen plate of the rear blade as the squeegee blade attached to the movable wall of the pair of front and rear blades can be set to an appropriate value. Details thereof will be described in detail in the description of embodiments to be described later.
[0011]
【Example】
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing an example in which the present invention is implemented in a solder paste screen printing apparatus.
[0012]
In the drawing, A is a pair of front and rear blades 2A, 2B that contact the upper surface of a metal screen 1 having a plurality of holes 1A at the bottom, and is positioned between the pair of blades so as to be openable and closable. A housing having a horizontally long supply port 3 and a chamber 5 for accommodating a solder paste 4 as a viscous printing material dispensed on the screen 1 through the supply port 3. In the screen printing apparatus according to the invention, the housing A and the supply port 3 are closed at the time of non-printing, are opened only at the time of printing, and the supply port opening / closing mechanism B operates so as to maintain the open state. Only when the housing A is advanced in the direction of the arrow X shown in FIG. 2 for printing, the rear blade of the pair of blades 2A and 2B is Over de 2B is provided with a squeegee device S configured to act as a squeegee blade. The housing A includes a pair of side walls 6A and 6B that are substantially parallel to each other in the moving direction, a front wall 7 fixed to an opposing wall surface of a front portion of the side wall, a rear wall 8, and tops of these four peripheral walls. A box-shaped hermetic housing is constituted by the fixed top wall 9.
[0013]
The rear wall 8 includes an upper fixed wall portion 8A and a lower movable wall portion 8B. The fixed wall portion 8A is fixed between the opposed inner wall surfaces of the rear portions of the pair of side walls 6A and 6B, and is movable. The wall portion 8B is screwed and fixed at its lower portion to a support shaft 11 loosely fitted into long holes 10A and 10B inclined obliquely forward and formed in the lower rear portions of the side walls 6A and 6B, respectively. At its upper part, it is loosely fitted in a long groove 12 that opens downward to the lower part of the fixed wall part 8A and extends over the entire length in the longitudinal direction thereof. Accordingly, the lower movable wall portion 8B is configured as a movable wall portion that can swing in the front-rear direction and can move up and down with a straight line extending in the lateral direction as a swing axis.
[0014]
In the illustrated example, the upper fixed wall portion 8A of the rear wall 8 is configured as a disassembleable assembly of three members: an upper wall member 8A1, an intermediate wall member 8A2, and a lower wall member 8A3. The long groove 12 is formed in the upper part of the lower wall member 8A3 below the projecting edge 8A3b projecting forward among the projecting edges 8A3a and 8A3b projecting horizontally forward and rearward. Further, the upper portion 8Ba of the lower movable wall portion 8B of the rear wall 8 is formed thinner than the main body portion 8Bb, and the upper tip portion 8Ba 'is formed round so as to freely move in the long groove 12. ing. In the figure, 8A1 'is a long groove formed on the bottom of the upper wall member 8A1, and 8A3' is a long groove formed on the upper surface of the lower wall member 8A3. These two members 8A1 and 8A3 are intermediate wall members. The upper and lower sides of 8A2 are connected to each other by press-fitting into the long grooves 8A1 'and 8A3'.
[0015]
As will be described later, the movable wall portion 8B of the rear wall 8 is operatively connected to the supply port opening / closing mechanism B, and the rear blade 2B is attached to the movable rear wall 8B and the front blade 2A is attached to the fixed front wall 7, respectively. It is fixed by being inclined obliquely downward and rearward through means 8B 'and 7A. During the printing operation, the front blade 2A scrapes off the solder paste residue 4 'that adversely affects the print finish adhered to the upper surface of the screen 1 during the previous printing prior to the squeegee operation by the rear blade 2B. It is configured to work as a cleaning blade.
[0016]
A means for kneading the solder paste 4 contained in the chamber 5 is provided between the pair of left and right side walls 6A and 6B of the housing A. In the example shown in the figure, the kneading means It is composed of two rotating rollers 13 and 14 that are horizontally traversed and arranged in two upper and lower stages at a required interval. These rollers 13 and 14 are operatively connected to reversible motors 17 and 18 respectively attached to small housings 15 and 16 fixed to the upper inner side of the respective side walls 6A and 6B via respective speed reduction mechanisms. It can be rotated by rotation of 17 and 18. In the illustrated example, the speed reduction mechanism is constituted by a belt drive mechanism. In the drawing, only the belt drive mechanism on the side of one side wall 6B is indicated by reference numeral 19 in FIG. The belt drive mechanism 19 is installed in a long hole 6 'provided vertically in each side wall, and a cover 6 "is mounted in the long hole 6'.
[0017]
In the illustrated example, the supply port opening / closing mechanism B operates on the movable wall portion 8B via the support shaft 11 and the pneumatic actuator 20 attached to the outer front portions of the both side walls 6A, 6B of the housing A, respectively. The link mechanism 21 is connected, and the supply port 3 of the squeegee device S is opened and closed by its operation. In the illustrated example, the link mechanism 21 is a bell crank 21A that is pivotally attached to the side walls 6A and 6B by a pivot 21A 'and is pivotally connected at one end to the piston rod 20A of the actuator 20. The other end of the bell crank is pivotally attached, and the other end is formed of a link 21B connected to a shaft portion 11A of the support shaft 11 described later. Therefore, in a state where the supply port 3 is closed, when the bell crank 21A is pulled by the piston rod 20A at one end thereof and pivots around the axis of the pivot 21A ', the support shaft 11 is moved to the long hole 10A by the link 21B. 10B, the movable wall portion 8B swings backward along the rear blade 2B in the direction away from the fixed front wall 7 with the upper tip portion 8Ba 'as a floating shaft. The supply port 3 is opened because it is urged. On the contrary, when the bell crank 21A is pushed by the piston rod 20A in a state where the supply port 3 is opened, the movable wall portion 8B is fixed together with the rear blade 2B via the link 21B and the support shaft 11 before being fixed. The supply port 3 is closed because the wall 7 is swung forward, that is, forward. The supply port opening / closing mechanism B is operated so that the supply port 3 is closed at the time of non-printing, opened only at every printing, and maintained in the open state.
[0018]
Reference numeral 22 denotes an adjustment mechanism for finely adjusting the height of the movable wall portion B, and the adjustment mechanism 22 is attached to the outer rear portions of the side walls 6A and 6B of the housing A, respectively. The adjustment mechanism 22 has a rectangular mounting plate 24 that is horizontally fixed to each side wall by a push screw 23, an adjustment screw 25 that vertically penetrates the mounting plate 24, and a screw hole 26 at an upper end portion. The movable adjustment plate 27 is a vertically long movable adjustment plate 27 in which a screw portion of an adjustment screw 25 protruding downward through the mounting plate 24 is inserted into the screw hole 26. A longitudinally long small hole 28 is provided at the center of each of which a pin 29 fixed to each of the side walls 6A and 6B is loosely fitted. 10B, a relatively large slot 30 inclined diagonally forward is formed, and the shaft of the support shaft 11 protrudes outward through the slot 10A, 10B on the side wall side. The portion 11A is loosely fitted. Further, the movable adjustment plate 27 is further provided with a vertically long small hole 31 similar to the above-described small long hole 28 in the lower portion of the long hole 30, and each side wall 6A, A pin 32 fixed to 6B is loosely fitted. A coil spring 33 is compacted between the mounting plate 24 and the movable adjustment plate 27 on the outer periphery of the screw portion of the adjustment screw 25 described above, and an adjustment guide is provided on the outer peripheral surface of the head 25A of the adjustment screw 25. A scale 25B is engraved.
[0019]
Since the adjusting mechanism 22 is configured as described above, if the adjusting screw 25 is appropriately rotated by pinching the head 25A with a fingertip, the movable adjusting plate 27 is screwed up and down in the vertical direction. In accordance with the momentum of movement, the support shaft 11 moves up and down along the inclined surfaces in the long holes 10A and 10B of the side walls, and accordingly, the movable wall portion 8B fixed to the support shaft 11 also moves. Since it moves up and down according to the amount of movement of the support shaft 11, the rear blade 2B as a squeegee blade fixed to the movable wall portion 8B also moves up and down integrally with the movable wall portion 8B. The illustrated adjusting mechanism 22 is configured so that the height of the movable wall portion 8B can be finely adjusted by about 1.5 mm. However, the adjustment width is appropriately set according to the material, thickness, etc. of the rear blade 2B. It is good also as a structure which increased / decreased.
[0020]
Reference numeral 34 denotes an opening formed in the upper center of the fixed wall portion 8A of the rear wall 8. The other end of the supply conduit connected to the opening 34 with a solder paste supply device (not shown) is connected to the opening 34. When the amount of solder paste in the chamber 5 decreases, the refilling device can be operated to refill the chamber 5 with solder paste. Reference numeral 35 denotes openings formed on both sides of the opening 34 with a predetermined interval, and an inert gas supply device (not shown) is connected to these openings 35 via a supply conduit. In addition, by blowing an inert gas into the chamber 5, the solder paste in the chamber 5 can be prevented from being oxidized.
[0021]
Reference numeral 36 denotes a partition wall made of a material having good thermal conductivity such as brass. The housing A is divided by the partition wall 36 into a space 38 for accommodating the chamber 5 and the temperature control device 37. The solder paste in the chamber 5 can be adjusted to an appropriate temperature by the temperature adjusting device 37. In the illustrated example, the temperature adjusting device 37 is composed of an electronic thermo 37A and a blower 37B. The blower 37B has an optimal temperature of the solder paste in the chamber 5, for example, a level of 24 to 26 °. When the temperature is exceeded, the temperature sensor 37 'disposed in the chamber 5 detects this and can be operated by a separate control unit (not shown) that operates in response to the detection signal. It has become.
[0022]
Reference numeral 39 denotes a baffle plate that also elastically contacts each outer peripheral surface of the two rotating rollers 13 and 14 facing the movable wall portion 8B and also serves as a partition member made of a steel plate. It serves to prevent the solder paste 4 from entering the guide and the gap between the rollers 13 and 14 and is supported by a support member 40. Reference numeral 41 is formed integrally with the front blade 2A, and its upper end is elastically brought into contact with the outer peripheral surface of the lower rotating roller 14 so as to perform the same function as the deflecting plate 39. It is a board.
[0023]
Reference numeral 42 is a known liftable printing stand that supports the printed circuit board P, which is a substrate, and is supported by a known lift control mechanism as shown in FIG. It can be moved up and down between the lowered position. Reference numeral 43 denotes a pair of left and right fixed screen plate support plates disposed on both the left and right sides of the printing table 42. The load of the squeegee device S that slides on the left and right sides of the squeegee device S is carried evenly from the lower side through the screen plate 1. Reference numeral 44 is a pair of left and right guide rails, 45 is a reciprocating sliding plate supported slidably on the guide rail 44, and 46 is a vertical movement of the squeegee device S fixed to the reciprocating sliding plate 45. A pneumatic actuator 47 serving as a driving mechanism for this is a belt driving mechanism for reciprocating the squeegee device S along the guide rail 44 horizontally.
[0024]
1 to 3, reference numeral 48 denotes a pair of left and right suspension mechanisms attached to the reciprocating sliding plate 45 and connected to the squeegee device S. In the illustrated example, the suspension mechanism is The pneumatic squeegee suspension mechanism is configured to lower the squeegee device S to absorb the shock when the pair of blades 2A, 2B are brought into contact with the screen 1, and to balance the left and right of the squeegee device S during printing. It works to measure.
[0025]
Next, the operation of the screen printing apparatus according to the present invention configured as described above will be described. FIG. 2 shows a state in which the printing operation by the squeegee device S moving forward in the direction of the arrow X is almost finished, and FIG. 3 is finished, and the squeegee device S is pulled up by the vertical movement mechanism 46. The state that has been displayed. The squeegee device S then moves in the direction of arrow Y and returns to its original position, where it waits for the next printing operation.
[0026]
When the squeegee device S is in the non-printing position, the supply port 3 is closed by the supply port opening / closing mechanism B, and the pair of front and rear blades 2A, 2B are also elastically contacted with each other at the lower end portion and closed. In this state, when the reversible electric motor 17 is started and the rotating roller 13 is rotated clockwise in FIG. 10, and the reversible electric motor 18 is started and the rotating roller 14 is rotated counterclockwise, the rollers 13, 14 and The solder paste present in the constricted area between the movable wall 8B is simultaneously subjected to the downward pressure applied by the upper roller 13 and the upward pressure applied by the lower roller 14, so that Therefore, the solder particles and the flux as the composition components are well agitated and kneaded, and kneaded into a solder paste having a uniform viscosity suitable for printing.
[0027]
When the squeegee device S is lowered from the original position and set to the printing start position on the screen 1, the movable wall portion 8B is loosely fitted into the long groove 12 of the fixed wall portion 8A by the supply port opening / closing mechanism B. The upper end 8Ba 'of the movable wall 8B is peristally displaced back to a predetermined position with the floating shaft as a floating axis, whereby the supply port 3 is opened, and the blades 2A and 2B are also released from the closed state accordingly. A sufficiently kneaded solder paste 4 can be supplied. When both or one of the rollers 13 and 14 is rotated in the clockwise direction in FIG. 9 simultaneously with the start of printing, the solder paste 4 has a high viscosity because a discharge pressure is applied to the solder paste 4. Nevertheless, it is automatically supplied onto the screen 1 smoothly.
[0028]
When the movable wall portion 8B is rearwardly displaced to a predetermined position, the lower end edge 2B ′ of the rear blade 2B as a squeegee blade is slightly lifted from the upper surface of the screen 1. For example, when the movable wall 8B swings about 3.5 ° from a plane perpendicular to the screen 1, the lower edge 2B 'of the rear blade 2B theoretically rises to a height of about 0.5 mm from the upper surface of the screen 1. However, a gap is generated between them. As a result, the printing pressure of the rear blade 2B with respect to the screen 1 becomes 0, and the solder paste supplied onto the screen 1 from the supply port 3 escapes backward from the gap, making it impossible to perform normal screen printing. .
[0029]
In the apparatus of the present invention, since the adjusting means 22 for finely adjusting the height of the movable wall portion 8B as described above is provided, it is possible not only to prevent the occurrence of the above disadvantageous situation, but also to be set adjustable. By finely adjusting the height of the movable wall portion 8B within the range, and accordingly the level of protrusion of the lower end edge 2B ′ of the squeegee blade 2B from the bottom surface of the squeegee device S, the printing pressure can be freely reduced. It has become possible to adjust.
[0030]
FIGS. 12 to 15 show another embodiment of the present invention. This embodiment is also an embodiment in which the present invention is applied to a solder paste screen printing apparatus, and its basic structure is the first embodiment described above. The configuration of each part is substantially the same as that of the first embodiment, and the configuration of each part is slightly modified, so that it is the same as each component or part of the first embodiment throughout the drawings. Members or parts are given the same reference numerals. Therefore, hereinafter, in order to avoid reversal of the description, the description will focus on the characteristic part of the second embodiment.
[0031]
The squeegee device S of the screen printing apparatus shown in FIGS. 12 to 15 as the second embodiment of the present invention divides the housing A into two parts up and down as a whole, and the upper housing divided body A1 and the lower housing divided body A2 are divided. They are characterized in that they are detachably connected to each other. The upper housing divided body (hereinafter referred to as the upper housing) A1 includes upper side wall portions (hereinafter referred to as upper side walls) 6A1 and 6B1 and lower side wall portions (hereinafter referred to as lower side walls) obtained by dividing the side walls 6A and 6B into two vertically. ) 6A2, 6B2, an upper front wall portion (hereinafter referred to as an upper front wall) 7A and a lower front wall portion (hereinafter referred to as a lower front wall) 7B formed by dividing the fixed front wall 7 into two parts vertically, and a rear wall 8 The fixed wall portion 8 </ b> A and the top wall 9. As the side walls 6A and 6B are divided into two parts in the vertical direction as described above, the long holes 6 'in the side walls equipped with the belt drive mechanism 19 and the cover 6 "of the long holes 6' are also vertically arranged. The upper half 6'A of the cover 6 "is formed in the upper half 6'A of the long hole 6 ', and the lower half 6 of the cover 6" is formed in the lower half 6'B of the long hole 6'. “B” is attached to each.
[0032]
12-15, each lower side wall 6A2, 6B2 has a width wider than the width of each upper side wall 6A1, 6B1 in the front-rear direction, protrudes in the front-rear direction, and extends upward at the front end portion and the rear end portion. Connection projections J1 and J2 rising vertically are provided, and the connection projections J1 and J2 are respectively formed with vertical engagement grooves J1′J2 ′. And the front connection projection part J1 is formed by notching the front upper part of each lower side wall 6A2, 6B2, and providing the recess R. As shown in FIG. On the other hand, engagement projections J3 that can be engaged with the engagement grooves J1 ′ and J2 ′ of the connection projections J1 and J2 on the end surfaces of the lower front end and the lower rear end of the upper side walls 6A1 and 6B1, respectively. , J4 project from each other, and these engaging projections J3, J4 are fitted and engaged with the engaging grooves J1 ', J2', thereby allowing the upper housing A1 and the lower housing A2 to be connected to each other. And the housing A can be assembled.
[0033]
Reference numeral 49 denotes a screw hole drilled at an appropriate position near the upper end of each of the connecting protrusions J1 and J2, and reference numeral 49 'denotes the engaging protrusions J3 and J4 corresponding to the screw holes 49. After the housing A is assembled as described above, screws (not shown) are inserted into the screw holes 49, 49 'and tightened to form the upper housing. A1 and lower housing A2 are integrally fixed to each other. In this way, the housing A composed of the upper and lower housings A1 and A2 that are integrally fixed to each other is required when the various components mounted inside the housing A need to be inspected / repaired or cleaned internally. Can be easily disassembled by removing the screws described above and pulling out the upper housing A1 from the lower housing A2.
[0034]
In principle, the operation or operation of each drive unit or operation mechanism of the device described above is sequence-controlled by a well-known sequence control device (not shown).
[0035]
As described above, the present invention has been described in detail with respect to an embodiment suitable for solder paste screen printing. However, the screen printing apparatus according to the present invention is not limited to the illustrated embodiment, and the scope described in the claims. This can be carried out by applying various modifications to this, and can also be carried out for screen printing of a viscous printing material having a relatively low viscosity such as printing ink.
[0036]
【The invention's effect】
The screen printing apparatus according to claim 1, wherein the lower wall portion of the rear wall of the housing to which the rear blade is attached is configured as a movable wall portion that can swing in the front-rear direction and move up and down. In this specification, the contact surface pressure of the rear blade as the squeegee blade with respect to the screen plate can be finely adjusted by finely adjusting the height of the movable wall portion. In particular, it is possible to effectively eliminate and improve the problems caused by excessive or insufficient printing pressure of the squeegee described in the previous section “Problems to be solved by the invention”, and realize high precision and high density of screen printing. In particular, it is suitable for screen printing of solder paste on a printed circuit board.
[0037]
According to the third aspect of the present invention, a printing material having a uniform viscosity as a whole can be supplied.
[0038]
According to the fourth aspect of the present invention, the solder paste can be maintained at a temperature optimum for printing.
[0039]
According to the fifth aspect of the present invention, the solder paste necessary for printing can always be secured in the chamber via the replenishing device. The oxidation of the solder paste can be prevented.
[0040]
The effects exhibited by the respective aspects of claims 7 to 10 are substantially the same as the operations and effects described in the embodiment.
[0041]
According to the eleventh aspect of the present invention, the housing can be easily disassembled into two upper and lower parts, so that not only is it very convenient for checking and repairing the components inside the housing, but also the inside of the chamber. It is possible to easily remove and clean the viscous printing material adhering to the ridge surface, the rotating roller, etc., especially the residue of the highly viscous solder paste.
[0042]
According to the twelfth aspect of the invention, since the load of the squeegee device is evenly carried on the pair of left and right support bases via the screen during printing, the printing pressure can be stabilized.
[Brief description of the drawings]
FIG. 1 is a rear view of an apparatus according to an embodiment of the present invention.
FIG. 2 is a side view of the device.
FIG. 3 is a side view of the device.
FIG. 4 is a perspective view of a squeegee device in the above device.
FIG. 5 is a perspective view of a rear wall of a housing of the squeegee device.
FIG. 6 is an exploded perspective view of the rear wall.
FIG. 7 is an exploded perspective view of the main part of the squeegee device.
FIG. 8 is an exploded perspective view of the main part of the squeegee device.
FIG. 9 is an enlarged side view of the squeegee.
FIG. 10 is an enlarged front view of the squeegee device.
FIG. 11 is an enlarged side view showing an opening state of a supply port of the squeegee device.
FIG. 12 is an exploded perspective view of a squeegee device in another embodiment of the present invention.
FIG. 13 is an exploded perspective view of the squeegee device.
FIG. 14 is an exploded side view of the squeegee device.
FIG. 15 is an assembled side view of the squeegee device.
[Explanation of symbols]
S squeegee device
A Housing
B Supply open / close mechanism
P Printed circuit board
1 screen
1A hole
2A Front blade
2B Rear blade
3 Supply port
4 Solder paste
5 Chamber
6A, 6B side wall
7 fixed front wall
8 Rear wall
8A Fixed wall of the rear wall
8B Movable wall of the rear wall
13, 14 Rotating roller
20 Pneumatic actuator
21 Link mechanism
22 Adjustment means
36 Bulkhead
37 Temperature controller
43 Support stand
44 Guide rail
45 Reciprocating sliding plate
46 Vertical movement mechanism
48 Suspension mechanism
A1 Upper housing
A2 Lower housing

Claims (12)

The screen plate includes a pair of front and rear blades contacting the upper surface of the screen plate at the bottom, and a horizontally long supply port positioned between the pair of blades and configured to be openable and closable. A housing having a chamber for storing a viscous printing material dispensed thereon, and the supply port is closed when not printing, is opened only at each printing, and operates so as to maintain the opened state. The pair of blades are in contact with the upper surface of the screen plate only when the housing is advanced for printing, and the rear blade of the pair of blades In a screen printing apparatus having a squeegee device configured to act as a squeegee blade, the rear wall of the housing is fixed upward. A wall portion and a lower movable wall portion that is swingably movable in the front-rear direction and vertically movable with a straight line extending in the lateral direction as a swing axis, and is operatively connected to the supply port opening / closing mechanism; The rear blade is fixed to the movable wall portion, and when the movable wall portion is swung back and forth by the supply port opening / closing mechanism, the rear blade is moved forward. The supply port is opened and closed by being brought into contact with and separated from the blade, and adjustment means capable of finely adjusting the height of the movable wall portion are provided on the respective outer sides of the left and right side walls of the housing. The contact surface pressure of the rear blade as a squeegee blade with respect to the screen plate can be finely adjusted by finely adjusting the height of the movable wall portion via Screen printing apparatus. The solder printing paste according to claim 1, wherein the viscous printing material is a solder paste used for mounting a chip-shaped electronic component on a printed circuit board and kneaded with a solder alloy powder and a high-viscosity liquid flux. The screen printing apparatus as described. 3. The screen printing apparatus according to claim 2, wherein means for kneading solder paste is provided in the chamber. 4. The screen printing apparatus according to claim 2, wherein the inside of the housing is divided into a chamber containing solder paste and a space containing the temperature control device by a partition wall having good thermal conductivity. 5. A structure in which a solder paste replenishing device capable of replenishing solder paste is combined with the chamber when the remaining amount of solder paste in the chamber decreases. The screen printing apparatus according to any one of the above. 6. The screen printing apparatus according to claim 1, wherein an inert gas supply device that blows an inert gas into the chamber is combined. 7. The screen printing apparatus according to claim 1, wherein the supply port opening / closing mechanism includes a pneumatic actuator and a link mechanism that operatively connects the actuator to the movable wall portion. . The screen printing apparatus according to claim 1, wherein the screen plate is a metal screen. 9. The screen printing apparatus according to claim 1, wherein the squeegee device is connected to a reciprocating sliding plate attached to the guide rail via a vertical movement mechanism and a suspension mechanism. Each time the printing is performed, the front blade is forced to feed the viscous printing material into the holes of the screen plate by the rear blade as a squeegee blade. The screen printing apparatus according to claim 1, wherein the screen printing apparatus is configured as a cleaning blade for removing residues. The screen printing apparatus according to claim 1, wherein the housing is divided into two parts in the vertical direction, and an upper housing divided body and a lower housing divided body are detachably connected to each other. A printing stand that can be moved up and down to support a printed circuit board that is a substrate to be printed, and a pair of left and right screen plate support stands that are disposed on both left and right sides of the printing stand, and is supported by the printing stand. The load of the squeegee device that slides on the screen plate supported by the pair of screen plate support bases to perform screen printing with respect to the substrate that has been formed is left and right from below through the screen plate support base. The screen printing apparatus according to any one of claims 1 to 11, wherein the screen printing apparatus is uniformly supported.

Images