JP4636297B2 - Screen printing device for screen printing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
[0001]
[Technical field to which the invention belongs]
The present invention relates to a screen plate cleaning device in a screen printing machine that prints a printing paste such as a solder paste or a conductive paste on a printed material such as a printed circuit board via a screen plate, and in particular, a lower surface or a pattern of the screen plate. The present invention relates to a screen plate cleaning device that removes dirt from apertures. .
[0002]
[Prior art]
In screen printing, especially screen printing of paste such as solder paste on a printed circuit board as a substrate to be printed, printing is performed while leaving dirt due to adhesion of paste residue, etc. on the lower surface of the screen plate and pattern openings inevitable. If the process is continued, printing defects such as bleeding, blurring, and disconnection occur in the paste pattern printed on the printed circuit board. Therefore, the screen plate must be cleaned by removing the stains as described above.
[0003]
Therefore, in the past, the screen plate was cleaned manually using paper, cloth, etc. In recent years, various types of devices that can automatically do this have been provided. Yes. However, all of these conventional examples have their merits and demerits, and when the paste residue having a relatively high degree of drying or solidification adheres to the lower surface of the screen plate or the pattern openings, the opening size is extremely small. In the case where a paste with extremely high viscosity such as a solder paste is adhered and remains in fine pattern openings, these conventionally known apparatuses generally remove the dirt efficiently and effectively. It was difficult to clean.
[0004]
The present invention has been made to eliminate and improve the above-mentioned inconveniences and disadvantages of the prior art, and efficiently and effectively removes paste residues such as solder paste adhered to the lower surface of the screen plate and the pattern openings. The main object of the present invention is to provide a screen plate cleaning device that can be easily removed, and particularly suitable for high-precision and high-density screen printing of a solder paste on a printed circuit board.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a screen plate cleaning device according to the present invention is a screen plate cleaning device in a screen printing machine that prints a paste on a printing material via a screen plate, and is in contact with the lower surface of the screen plate. When moved in a state, a first residue removing means capable of slidingly removing the paste residue adhering to the lower surface of the screen plate, and the first residue removing means move together with the movement. A first cleaning head having both a second residue removing means capable of sucking and removing the paste residue adhering to the inner surface of the pattern opening of the screen plate from below the screen plate; The cleaning head is arranged to move integrally with the first cleaning head at the front or rear in the moving direction of the cleaning head. And a pair of front and rear cleaning rollers that move in a state of being indirectly in contact with the lower surface of the screen plate via a cleaning sheet, and a portion of the cleaning sheet to which the front roller applied a solvent along with the movement. The rear roller is provided with a second cleaning head which can clean the dirt on the lower surface of the screen plate at the portion of the cleaning sheet where the solvent is not applied. .
[0006]
For other structural features of the screen plate cleaning device in the screen printing machine according to the present invention, refer to the description items of claims 2-8.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing two preferred embodiments.
[0008]
For convenience, the above-described second cleaning head will be described first, and then the first cleaning head will be described.
[0009]
In the drawings, 1 is a screen plate as a metal screen set on a screen printing machine (not shown) via a screen holding frame, 2 is a cleaning sheet made of paper or non-woven fabric produced in a strip shape, 2 Side plate of the cleaning head A, 4 is a sheet supply unit for supplying a cleaning sheet (hereinafter referred to as a sheet), 5A and 5B are the front side while pressing the sheet 2 drawn from the sheet supply unit against the lower surface of the screen plate 1, A pair of rotatable cleanings arranged in parallel with a predetermined distance between the side plates 3 so as to remove the printing paste residue R1 and the like adhering to the lower surface of the screen plate by moving in the direction of arrow X. A roller 6 elastically pushes the sheet 2 against the lower surface of the screen plate 1 by the pair of cleaning rollers 5A and 5B. A sheet / pass line mechanism for continuously transferring the cleaning rollers 5A and 5B in the cleaning direction while rotating them around the horizontal axis in a staggered state, and 7 is a rear cleaning roller between the pair of cleaning rollers 5A and 5B. Solvent application means for continuously applying a solvent 8A having a dissolving power for a printing paste such as a solder paste to the sheet 2 that moves from 5B to the front cleaning roller 5A.
[0010]
In the illustrated example, the sheet 2 used for cleaning is a non-woven fabric made of paper or cotton having both flexibility and liquid absorption and / or air permeability produced in a strip shape, In the illustrated example, the sheet supply unit 4 is formed as a box-like container, and is pivotally mounted around the horizontal axis between the left and right side plates 3 at the inner seat. The sheet 2 is folded in an accordion curtain shape and accommodated in the box-like container 4 so as to be able to be drawn out. 4A is a handle for manually opening and closing the container 4, and 4B is a container lid that can be opened and closed.
[0011]
In the illustrated example, the sheet / pass line mechanism 6 includes a guide roll 9 disposed immediately above a box-like container 4 serving as a sheet supply unit, a rear cleaning roller 5B, and both cleaning rollers 5A, The intermediate roller 10 having a large diameter as a pinch roller disposed between the 5B and a portion of the sheet 2 extending between the cleaning rollers 5A and 5B from below is driven. A driving roller 11 having a diameter smaller than that of the intermediate roller 10, a front cleaning roller 5A, a guide roll 12 disposed on the downstream side of the cleaning roller, a tension roll 13 provided near the lower portion of the guide roll 12, The tension roller 13 is disposed below, one of which is a focus roller 14 and the other is a drive roller. As 15, and consists of a pair of rollers 16. to pass the sheet 2 therebetween, the installation of the winding device comprising a winding roller and its drive mechanism winding up the seat 2 is omitted. A driving roller 11 that rotationally drives the intermediate roller 10 via the sheet 2 and a driving roller 15 of the pair of rollers 16 constituting the terminal portion of the sheet pass line mechanism 6 are a belt or chain driving mechanism, which will be described later. It is to be driven by.
[0012]
In the example shown in the drawing, the solvent application means 7 comprises a drive roller 11 that drives the cleaning sheet 2 against the intermediate roller 10 and a drive mechanism thereof, and the drive roller 11 is provided below the drive roller 11. In addition, it also has a function as an application roller that allows the solvent 8A continuously fed from the solvent tank 8 containing the solvent 8A to be immersed in the sheet portion as it rotates. The drive roller 11 having the function as the application roller is rotationally driven by a belt or chain drive mechanism 18 including an electric motor 17 attached near the lower portion of the solvent tank 8. Further, the other driving roller 15 described above is rotationally driven by another belt or chain drive mechanism 18B using the electric motor 17 as a common power source.
[0013]
In the figure, reference numerals 19, 20, and 21 denote trough-like members that detachably accommodate the preceding cleaning roller 5A, the intermediate roller 10, and the subsequent cleaning roller 5B, respectively, and 22 is connected to the members 19 and 20 at the bottom. A semi-cylindrical member having a substantially cross-sectional shape having an elongated opening 22A allowing contact between the intermediate roller 10 and the driving roller 11, springs for biasing the cleaning rollers 5A and 5B upward, 11 ' Is a member having a liquid absorbing property for continuously replenishing the solvent 8A in the solvent tank 8 to the outer peripheral surface of the drive roller 11, and 23 is elastically supporting the end of the L-shaped support arm 24 of the drive roller 15. This is a box with a spring 25 attached to the upper part thereof.
[0014]
Next, the first cleaning head described above will be described. The cleaning head A has a form of a horizontally long hollow housing, and extends in a lower housing A1, an upper housing A2 detachably mounted on the housing A1, and a direction orthogonal to the cleaning direction, that is, a left-right direction. And a suction nozzle portion A3 which comprises a slit-like air inlet 30 which opens toward the lower surface 1A of the screen 1 and which is attached to the upper housing A2 so as to be detachable and replaceable. The second cleaning head B is erected on a common base 31 supported by an air cylinder C as a lifting drive means together with the second cleaning head B, and the air cylinder C and the base via a drive mechanism (not shown). It is possible to rotate 180 ° around the vertical axis integrally with 31.
[0015]
The first residue means of the first cleaning head A as a sliding removal means for the paste residue R1 attached to the lower surface 1A of the screen plate 1 extends in a direction perpendicular to the moving direction, that is, in the left-right direction, It consists of a spatula 32 that is elastically supported via a spring 31 so as to be vertically movable and tiltable in the left-right direction. In the illustrated example, the suction nozzle portion A3 includes a bottom wall 33 having an opening 33A communicating with the housing hollow portion A2 'of the upper housing A2, and an opposingly formed octagonal cross section. The wall portion 34 and left and right side wall portions 35 fixed to both ends of the opposite wall portion 34 are configured. The spatula 32 held by the holder 32A is disposed on the inner side of the opposite wall portion. The slit-like air inlet 30 is elastically supported by a spring 31 as a compression coil spring through a holder 32A in an elongated box 36 having a channel-shaped groove extending in the middle. It is attached so as to be detachable and replaceable in a manner slightly protruding upward. The spatula 32 is desirably formed thin with a material having both rigidity and elasticity, such as a thin steel plate, but may be formed with a durable hard synthetic resin.
[0016]
Reference symbol A1 'denotes a housing hollow portion communicating with the housing hollow portion A2' via a filter 37. The suction portion is formed larger than the former and has one end connected to an external intake device (not shown) therein. A connection hole 38 for connecting the other end of the hose or duct is opened.
[0017]
In the apparatus shown in FIG. 1, when the cleaning is performed while moving in the direction of the arrow X, that is, forward, the second cleaning head B is positioned behind the first cleaning head A, and the first cleaning head A The cleaning is carried out following the cleaning by. And the movement to the front-back direction is performed by the reciprocating drive mechanism not shown.
[0018]
In the screen plate cleaning apparatus configured as described above, the apparatus body composed of the first and second cleaning heads A and B is activated from the standby position to the cleaning start position by starting up and down driving means C, and the first cleaning head A The spatula 32 as the first residue removing means is elastically brought into contact with the screen plate lower surface 1A, and the cleaning sheet 2 is elastically applied to the screen plate lower surface 1A via the cleaning rollers 5A and 5B of the second cleaning head B. And the air intake device connected to the first cleaning head A is operated, and the sheet / pass line mechanism 6 of the second cleaning head B is activated. In this state, when the reciprocating activation mechanism is operated to move the apparatus main body in the direction of arrow X, first, as shown in FIG. 4, the spatula 32 of the preceding first cleaning head A is moved to the lower surface of the screen plate. The paste residue R1 adhering to 1A is slid and removed, and the suction nozzle portion A3 as the second residue removing means is slid by the paste residue R2 adhering to the inner surface of the pattern hole 1B of the screen plate 1 and the spatula 32. The residue R1 removed by movement and the residue attached to the spatula 32 during the cleaning operation are removed by suction.
[0019]
Next, in the second leaning head B that continues to the first cleaning head A, the cleaning sheet 2 slides in the cleaning direction while rotating the cleaning rollers 5A and 5B and adheres to the bottom surface of the screen plate R1. In this case, the solvent application means 7 is operated to apply the solvent 8 to the sheet 2 passing between the intermediate roller 10 and the driving roller 11 and soak the solvent. Since the preceding cleaning roller 5A located on the downstream side moves while pressing the portion of the sheet 2 in which the solvent has permeated against the lower surface of the screen plate, the adhesion residue R1 is solidified and cannot be completely removed by the first cleaning head A. Even in such a case, the remainder can be removed effectively and continuously. Since the continuously transported sheet 2 is dry on the upstream side of the solvent application means 7, the portion of the dry sheet 2 that passes over the subsequent cleaning roller 5B is screened by the roller 5B. Since it slides in pressure contact with the lower surface of the plate, it is effective and continuous following the cleaning with the solvent to clean the lower surface of the screen plate soiled with the solvent R2 or the solvent R2 containing the residue R1 attached to the lower surface of the screen plate by using the solvent. Can be wiped off.
[0020]
The portion of the sheet 2 soiled by cleaning in this manner is continuously discharged through the pair of rollers 16 at the end of the sheet / pass line mechanism 6, and in this case, for example, as shown in FIG. If a cardboard box, a trash box, etc. that can be easily carried is prepared, the used sheets can be automatically accommodated in the box H as shown in the figure, and this is exceptional after cleaning work. Can be easily disposed of without the need for
[0021]
Since the screen plate is usually made of a thin metal plate or the like, it is easily deformed, and even when used for screen printing for a certain period of time, for example, about 8 hours, it tends to cause a problem that distortion such as deformation easily occurs. However, since the spatula 32 as the first residue removing means in the present invention is elastically supported via a spring so as to be movable up and down and tilted, the screen plate itself is deformed or smooth. Even if there is a missing part, it operates so as to automatically follow the deformed or distorted part so as to maintain the close contact state, so that it is possible to cleanly remove the adhesion residue R1.
[0022]
If it is determined that the cleaning is incomplete when the apparatus main body moves in the direction of arrow X and reaches its end point, it is lowered, turned 180 ° and then raised, what is the direction of arrow X? The cleaning may be continued by moving in the opposite direction.
[0023]
FIG. 5 shows an example in which the second cleaning head B is disposed in front of the first cleaning head A when viewed in the direction of the arrow X. In this example, the second cleaning head B precedes the first cleaning head A. Since the residue R2 in the pattern opening 1B of the screen plate 1 is softened by the application of the solvent, it becomes easy to remove the clogging by the first cleaning head A. Even if it is used when it is clogged or when the opening 1B is fine and it is difficult to remove the internal residue R2, high removal efficiency can be obtained.
[0024]
Since the present invention is configured as described above, according to this, it is possible to eliminate and improve the disadvantages and disadvantages of the prior art described above, and adhere to the lower surface of the screen plate and the pattern openings. It is possible to obtain a screen plate cleaning device suitable for high-precision and high-density screen printing such as solder paste on a printed circuit board, which can efficiently and effectively remove paste residues such as solder paste and solvent. Is.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of a main part of a screen plate cleaning apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic side view illustrating the operation of a second cleaning head.
FIG. 3 is a perspective view of a second cleaning head.
FIG. 4 is a partially enlarged vertical side view for explaining the operation of the apparatus.
FIG. 5 is a longitudinal sectional view of an apparatus according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Screen plate A 1st cleaning head A3 2nd residue removal means B 2nd cleaning head 2 Cleaning sheet 4 Sheet supply part 5A, 5B Cleaning roller 6 Sheet pass line mechanism 7 Solvent application means 30 Air inlet 32 First residue removal means

Claims (8)

A screen plate cleaning device in a screen printing machine that prints a paste on a printing material via a screen plate, and when the plate plate is moved in contact with the lower surface of the screen plate, A first residue removing means capable of slidingly removing the adhered paste residue, and a paste residue which has moved integrally with the first residue removing means and adhered to the inner surface of the pattern opening of the screen plate A first cleaning head having a second residue removing means capable of sucking and removing from the lower side of the screen plate, and the first cleaning head forward or backward in the moving direction of the first cleaning head. It is arranged so that it moves as a unit, and as it moves, it indirectly contacts the lower surface of the screen plate via a cleaning sheet. A pair of front and rear cleaning rollers that move in a state where the front roller is a portion of the cleaning sheet to which a solvent is applied, and the rear roller is a portion of the cleaning sheet that has not been applied with a solvent. And a second cleaning head capable of cleaning dirt on the lower surface of the screen plate. 2. The apparatus according to claim 1, wherein the first residue removing means of the first cleaning head extends in a direction perpendicular to the moving direction thereof, and is elastic through a spring so as to be vertically movable and tiltable. A screen plate cleaning device comprising a spatula supported on a screen. 3. The apparatus according to claim 1, wherein the second cleaning head moves forward while pressing a cleaning sheet pulled out from the sheet supply unit that supplies the cleaning sheet against the lower surface of the screen plate. A pair of rotatable cleaning rollers disposed in parallel at a predetermined interval in front and rear so that residues of the printing paste adhered to the lower surface of the screen plate can be removed, and a cleaning sheet by the pair of cleaning rollers. The sheet and pass line mechanism for continuously transferring the cleaning roller in the cleaning direction while rotating the cleaning roller while being pressed against the lower surface of the screen plate, and the transition from the rear cleaning roller to the front cleaning roller between the pair of cleaning rollers Cleaning system Screen plate cleaning device which is characterized in that a solvent coating means for continuously applying the solvent and. 4. The screen plate cleaning apparatus according to claim 1, wherein the take-up device for winding up the cleaning sheet at the portion used for cleaning the screen plate is omitted. The cleaning sheet is a paper or non-woven fabric produced in a strip shape, the sheet supply unit is formed as a box-shaped container, and the strip-shaped cleaning sheet is folded in an accordion curtain shape to form a box-shaped container 5. The screen plate cleaning apparatus according to claim 1, wherein the screen plate cleaning unit is housed so as to be capable of being pulled out. 6. The screen plate cleaning apparatus according to claim 1, wherein the solvent application means extends between the cleaning rollers via an intermediate roller disposed at a lower portion between the pair of cleaning rollers. A roller that is driven by pressing a portion of an existing cleaning sheet against the intermediate roller, the solvent being continuously fed from a solvent tank provided on the lower side of the roller along with the rotation of the cleaning sheet portion A screen plate cleaning device comprising a driving roller having a function as a coating roller soaked into the screen and a driving mechanism thereof. 7. The screen plate cleaning apparatus according to claim 1, wherein the substrate to be printed is a printed circuit board, and the paste is a solder paste for surface mounting. The one according to any one of claims 1 to 7, wherein the first cleaning head and the second cleaning head are erected on a common base supported by a lift drive means, A screen plate cleaning device, wherein the screen plate cleaning device is capable of being rotated by 180 ° around a vertical axis integrally with the lifting drive means and the base.

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