JP4188910B2 - Screen printing device - Google Patents

Description

【Technical field】
[0001]
The present invention relates to a screen printing apparatus, and more particularly, to a screen printing apparatus provided with a cleaning unit that uses a cleaning liquid to clean a screen plate that has become dirty by using screen printing of paste such as solder paste on a substrate such as a printed circuit board. Regarding improvement.
[Background]
[0002]
When a paste such as a solder paste is printed on a substrate surface by a screen printing apparatus, it is difficult to avoid the residue of the paste on the upper and lower surfaces of the screen plate used for this and the inner surface of the pattern hole. Cleaning the screen plate is indispensable in order to prevent the occurrence of printing defects such as pattern defects and bridging between patterns due to adhesion of strike residues.
[0003]
In view of this, various screen printing apparatuses including a cleaning unit that wipes the screen plate using a cleaning liquid have been proposed. As a cleaning unit used in such a screen printing apparatus, there is known a cleaning unit in which a cleaning liquid is sprayed on a screen plate in the form of a shower or sprayed and sprayed to clean the screen.
[0004]
However, in recent years, with the trend toward further miniaturization, higher density, higher integration, etc. of electronic devices, screen printing performed prior to surface mounting of electronic components on printed circuit boards etc. The actual situation is that the trend toward higher definition and higher density of pattern openings in screen plates used is increasing.
[0005]
In this way, when the paste residue adheres to the high-definition and high-density pattern openings, or when the paste residue adhering to the surface of the screen plate is cured, it is simply a washing liquid. It is difficult to remove these paste residues simply by spraying or spraying in a shower form.
[0006]
Therefore, in order to eliminate the drawbacks of the prior art as described above, the nozzles arranged on the upper and lower surfaces of the screen plate set horizontally as described in Japanese Patent Application Laid-Open No. 8-39786 at the top of the hill. Then, the cleaning liquid is sprayed on both the upper and lower surfaces of the screen plate, and a cleaning unit appears that wipes the upper and lower surfaces with wipers respectively disposed on the upper and lower surfaces of the screen plate. Has reached.
[0007]
However, in any of the above-described types of screen printing apparatuses, the screen printing unit and the cleaning unit are housed in separate boxes, and the screen plate can be inserted into and removed from each box manually. This is performed through a conveying means such as a conveyor extending between openings of the screen plate provided in each box. The latter is disclosed in Japanese Patent Laid-Open No. 8-39786, and the screen plate opening / closing opening of the box housing the cleaning portion is opened to the outside as clearly shown in FIGS. 1 and 5 of the publication. Yes. Therefore, the former type causes a decrease in the efficiency of screen printing, and the latter type is caused by volatilization of the cleaning liquid used during the cleaning of the screen plate in the box constituting the cleaning chamber. It is unavoidable that the diffused exposure of the gas body, which is harmful to the health and uncomfortable, can be avoided, and pollutes the work environment. In this case, it is not sufficient to ventilate the installation site of the equipment, and it does not mean that fundamental environmental protection measures have been taken. In addition, since any of the types of the above-described prior art cannot avoid an increase in the size of the entire apparatus due to its structure, the space for installation must be increased.
[0008]
In addition, with the recent increase in the density of printed patterns on substrates, there has been a demand for more completeness with respect to the cleaning of paste residues, and the cleaning liquid to be used is required to have a high cleaning efficiency. ing. As a result, alcohol-based solvents with high volatility and strong odor have come to be used as an efficient cleaning solution. However, while having good cleaning efficiency, it is necessary to establish effective environmental measures such as deodorization. It is coming.
DISCLOSURE OF THE INVENTION
[0009]
The main object of the present invention is that the screen plate can be cleaned automatically and efficiently without human intervention, and it is sufficient to cope with the use of a cleaning solution having high volatility and strong odor. The object is to provide a screen printing apparatus with environmental protection measures.
[0010]
Another object of the present invention is to provide a screen printing apparatus that can reduce the size of the entire apparatus and does not require a large space for installation.
[0011]
In order to achieve these objects, the present invention provides a screen printing unit including a squeegee unit that prints a paste through a screen plate having a plurality of pattern openings on an upper surface of a substrate set on a printing table, and a wipe. An upper cleaning unit and a lower cleaning unit each having a member, and the screen plate is sandwiched between the upper cleaning unit and the lower cleaning unit from the upper surface side and the lower surface side, and the state In the screen printing apparatus comprising a cleaning unit that removes paste residue adhering to the screen plate using a cleaning liquid while moving both cleaning units synchronously, the interior of a single casing is partitioned by a vertical partition. Next to each other A cleaning chamber is formed, the screen printing unit is accommodated in the printing chamber, the cleaning unit is accommodated in the cleaning chamber, and an opening that allows the printing chamber and the cleaning chamber to communicate with each other. And a pair of guide rails extending in parallel and horizontally inside the printing chamber and the cleaning chamber through the opening, and screen printing on the upper surface of the substrate in the screen printing portion. A conveying means for reciprocally moving the screen plate along the guide rail between a printing position to be performed and a cleaning position at which the screen plate is cleaned in the cleaning unit; and The cleaning chamber is caused by the volatilization of the cleaning solution used during the cleaning of the screen plate. It is characterized in that it comprises a blocking means which is adapted to prevent the flow to the printing chamber of a gas having an odor that occurs.
[0012]
Another object of the present invention is that each of the wiping member of the upper cleaning unit and the wiping member of the lower cleaning unit has a form as a horizontally long plate-like body, and a cleaning sheet that can be impregnated with a cleaning liquid is provided at the tip thereof. It is desirable that pressure contact is possible so that pitch feed is possible.
Preferably, the upper cleaning unit is provided with supply means for supplying an appropriate amount of cleaning liquid directly to the upper surface of the screen plate.
The opening of the partition wall is preferably formed in a size and shape necessary and sufficient for the screen plate to pass through the opening together with the holding frame.
The blocking means may comprise a shutter mechanism comprising a shutter plate that can move up and down to open and close the opening of the partition and an air cylinder that moves the shutter plate up and down.
The blocking means may comprise an air curtain mechanism that fluidly blocks the opening of the partition wall.
It said blocking means is operated so as to maintain the gas pressure in the cleaning chamber to a negative pressure lower than the atmospheric pressure of the printing chamber, located outside of the casing, and evacuating the inside of the gas into the cleaning chamber to the outside through the exhaust conduit can be composed of linked exhaust system to.
During Cree-learning operations of the screen plate, said Ke - it is desirable to the inert gas supply source that is installed outside the single to supply the clean-learning chamber inert gas.
During cleaning operation of the screen printing plate, said Ke - from the inert gas supply source which is installed outside the single to the cleaning chamber while supplying an inert gas, smelling generated by volatilization of the supplied inert gas and the cleaning liquid The mixed gas with the gas may be discharged to the outside by an exhaust device installed outside the casing and connected to the cleaning chamber via an exhaust conduit and a gas filter.
BEST MODE FOR CARRYING OUT THE INVENTION
[0013]
Hereinafter, a screen printing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0014]
FIG. 1 shows an outline of the overall configuration of a screen printing apparatus as an example of an embodiment of the present invention. The screen printing apparatus S includes a single casing H, and a screen printing unit 10 and a cleaning unit 20 which are accommodated and disposed separately from each other in the casing as will be described later. The screen printing unit 10 mounts a printed board 11 loaded from the outside through a carry-in port (not shown) provided in the casing H and sets the board 11 at a printing position and a plurality of pattern openings. The squeegee portion 13 having a hole 30A and having a squeegee for printing a paste such as a solder paste on the upper surface of the substrate 11 through a screen plate 30 stretched on the retaining frame 30B. Reference numeral 14 denotes a printing chamber in which the screen printing unit 10 is housed and disposed. The printing chamber 14 is separated from the cleaning chamber by a partition as will be described later. The cleaning unit 20 includes a lower cleaning unit 21 having a wiping member 21A for cleaning the lower surface of the screen plate 30, and an upper cleaning unit 22 having a wiping member 22A for cleaning the upper surface of the screen plate 30. It has.
[0015]
23 is a cleaning liquid discharge nozzle having a pipe-like form as a pre-cleaning liquid supply means. The cleaning liquid discharge nozzle 23 is connected to an external supply device (not shown), and is disposed on the upper surface of the screen plate 30 when the screen plate 30 is cleaned. The appropriate amount of the washing liquid is directly discharged. The cleaning liquid discharge nozzle 23 is integrally attached to the upper unit 22. Reference numeral 24 denotes a cleaning chamber in which the cleaning unit 20 is accommodated. Reference numeral 31 denotes a vertical partition that partitions the inside of the casing H to form the printing chamber 14 and the cleaning chamber 24 adjacent to each other, and 32 is an opening that allows the printing chamber and the cleaning chamber to communicate with each other. Reference numeral 33 denotes a pair of guide rails that extend through the opening 32 in parallel and horizontally to the inside of the printing chamber and the cleaning chamber. In the vicinity of the guide rail 33, a conveying means (for reciprocating movement between a printing position where screen printing is performed on the upper surface of the substrate 11 in the screen cleaning unit 10 and a cleaning position where the screen plate 30 is cleaned in the cleaning unit 20 ( (Not shown). Reference numeral 34 denotes a shutter mechanism as blocking means that can block the flow of a gas body having an odor generated in the cleaning chamber 24 due to volatilization of the cleaning liquid used for cleaning the screen plate 30 into the printing chamber 14. Thus, the mechanism 34 includes a shutter plate 34A that can move up and down to open and close the opening, and an air cylinder 34B that moves the shutter plate up and down.
[0016]
Reference numeral 35 denotes a control device storage chamber provided in the upper portion of the cleaning chamber 24, in which a control device for controlling the printing unit 10, the cleaning unit 20 and the like is stored and installed. Reference numeral 36 denotes an inert gas supply unit for supplying an inert gas such as nitrogen gas into the cleaning chamber 24 through the storage chamber. Reference numeral 35A denotes a gas inlet provided in the storage chamber 35, and reference numeral 35B denotes a gas supply port that opens into the cleaning chamber 24.
[0017]
37 is an exhaust device for exhausting the atmospheric gas in the cleaning chamber 24 to the outside through the exhaust port 38, the exhaust conduit and the gas filter.
[0018]
Next, the operation of the screen printing apparatus will be described.
[0019]
The substrate 11 carried into the printing chamber 14 by a transport device (not shown) is placed on the printing table 12, set on the printing device, and then pressed against the screen plate 30. Thereafter, the squeegee unit 13 waiting upward is lowered onto the screen plate 30 and moved in either the left or right direction in FIG. 2 to perform a printing operation. As a result, a paste such as a solder paste is printed on the substrate 11 via the screen plate 30. When one printing operation is completed, the substrate 11 is unloaded and the shutter plate 34A of the shutter mechanism 34 is raised to open the opening 32, so that the screen plate 30 is transferred from the printing chamber 14 to the cleaning chamber 24. 4 is moved to the right. Thereafter, the shutter plate 34 descends to close the opening 32. When the opening 32 closes and the screen plate 30 reaches the cleaning position shown in FIG. 1, the lower surface cleaner 21 rises and the upper surface cleaner 22 descends to sandwich the screen plate 30 with its wiping members 21A and 22A . It will be in the state to press. A cleaning sheet C made of paper or cloth is press-contacted to the front ends of the wiping members 21A and 22A of the cleaners 21 and 22 by a known means so as to be pitch-feedable. Then, both cleaners 21 and 22 synchronize and reciprocate in the left-right direction in FIG. 3 to clean the upper and lower surfaces of the screen plate 30. At this time, from the cleaning liquid discharge nozzle 23 integrally attached to the upper surface cleaner 22, a highly volatile alcohol-based solvent (for example, isopropyl alcohol) is used as a cleaning liquid having a high cleaning effect as shown in FIG. An appropriate amount is directly discharged onto the upper surface of the plate 30 and cleaned while infiltrating the cleaning sheet. Thereby, the paste residue adhering to the upper and lower surfaces of the screen 30 and the inner surface of the pattern hole is effectively cleaned while being dissolved, and the paste residue is adsorbed to the cleaning sheet C. Both cleaners 21 and 22 a predetermined number of times, after reciprocated, performs up wiping the unused portion sends a cleaning sheet C after brought into contact with the screen plate 30, the dry air by gas discharge device (not shown) or An inert gas such as nitrogen gas is sprayed onto the screen plate 30 to promote drying of the plate surface.
[0020]
On the other hand, an inert gas such as nitrogen gas is pumped into the cleaning chamber 24 from the inert gas supply unit 36 through the control device storage chamber 35 in accordance with the start of the cleaning, and the volatility in the cleaning chamber 24 is increased. In addition to lowering the vapor concentration of the high cleaning liquid, the exhaust device 37 discharges the odorous gas body composed of the mixed gas of the inert gas and the volatile gas of the preclean liquid from the exhaust port 38, and passes through the exhaust conduit and the gas filter. And exhaust outside without affecting the work environment. As a result, all of the odorous gas containing the cleaning solution vapor is filtered and exhausted to the outside, and finally the cleaning chamber 24 is filled with an inert gas such as nitrogen gas.
[0021]
Next, the screen plate 30 that has been cleaned is transferred from the cleaning chamber 24 to the printing chamber 14 by a procedure reverse to the above procedure, and a series of operations from the start of printing to the end of cleaning is completed. At this time, the shutter mechanism 34 is temporarily opened. However, since all the atmospheric gas in the cleaning chamber 24 containing the steam of the cleaning machine is exhausted, the odor of the cleaning liquid leaks to the printing chamber 14 side and the vicinity thereof. It does not spread.
[0022]
In the above-described embodiment, isopropyl alcohol having strong flammability as well as odor is described as an example of the cleaning liquid. Therefore, an inert gas such as nitrogen gas is used to supply the cleaning chamber 24 and accelerate the drying of the screen plate 30. However, if a cleaning liquid with low flammability is used, dry air may be used. In this case, the inert gas supply unit 36 may be replaced with an air compressor in which an air dryer is interposed in the pipeline. Further, from the viewpoint of explosion prevention, an inert gas such as nitrogen gas is supplied to the cleaning chamber 24 via the control device storage chamber 35, but this is also unnecessary, and dry air may be supplied directly to the cleaning chamber 24.
[0023]
In the above embodiment, the opening 32 is closed by the opening closing device 34. However, if the exhaust device 37 is controlled so as to keep the inside of the cleaning chamber 24 at a negative pressure lower than the atmospheric pressure, the opening since 32 atmospheric gas in the cleaning chamber 24 to the printing chamber 14 there is no Re risk of leakage, there may be no opening closure mechanism 34.
[0024]
FIG. 5 is a longitudinal side view showing an outline of the overall configuration of a screen printing apparatus as another example of the embodiment of the present invention.
[0025]
In FIG. 5, 39 is an air curtain mechanism, and the air curtain mechanism 39 replaces the opening closing mechanism 34 in the above example. According to this embodiment, the printing chamber 14 and the cleaning chamber 24 can always be fluidly shut off regardless of the transfer of the screen plate 30 or the like. There is no leakage inside or around the printing device. The gas used for the air curtain mechanism 39 may be appropriately selected from inert gas such as nitrogen gas or dry air according to the cleaning liquid used in the same manner as in the above example. In addition, the same code | symbol is attached | subjected about the structure same as the above-mentioned one example, and description is abbreviate | omitted.
[0026]
The embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to the embodiments, and various modifications are made within the scope of the claims. It is possible to implement.
[Industrial applicability]
[0027]
The screen printing apparatus according to the present invention is configured as described above, and can automatically and efficiently perform the cleaning of the screen plate without relying on human hands, and can prevent the odor leakage of the cleaning liquid. A cleaning liquid used for enhancing the cleaning effect of the screen plate can be freely selected, and the screen plate having a high-density printing pattern can be effectively wiped off.
[0028]
In addition, there is an effect that it is possible to prevent an accidental explosion caused by the cleaning liquid vapor.
[Brief description of the drawings]
[0029]
FIG. 1 is a longitudinal side view showing an outline of the overall configuration of a screen printing apparatus as an example of an embodiment of the present invention.
2 is a cross-sectional view taken along line AA in FIG.
3 is a cross-sectional view taken along line BB in FIG.
4 is a cross-sectional view taken along the line CC of FIG.
FIG. 5 is a longitudinal sectional side view showing an outline of the overall configuration of a screen printing apparatus as another example of an embodiment of the present invention.
FIG. 6 is a longitudinal front view showing an outline of the operation state of the cleaning unit.

Claims (9)

  From a screen printing unit including a squeegee unit that prints paste through a screen plate having a plurality of pattern openings on the upper surface of a substrate set on a printing table, and an upper cleaning unit and a lower cleaning unit each having a wiping member The screen plate is sandwiched between the wiping member of the upper cleaning unit and the wiping member of the lower cleaning unit from the upper surface side and the lower surface side, and the cleaning liquid is moved while both the cleaning units are moved synchronously in that state. And a cleaning unit that removes paste residue adhering to the screen plate and partitioning the interior of a single casing with a vertical partition to form a printing chamber and a cleaning chamber adjacent to each other. , In the printing room The screen printing unit is provided so that the cleaning unit is accommodated in the cleaning chamber, and the partition is provided with an opening that allows the printing chamber and the cleaning chamber to communicate with each other. A pair of guide rails extending in parallel and horizontally inside the printing chamber and the cleaning chamber, a printing position where screen printing is performed on the upper surface of the substrate in the screen printing unit, and the screen in the cleaning unit. A conveying means for reciprocating the screen plate along the guide rail between a cleaning position where the plate is cleaned, and a cleaning liquid used for the screen plate during a cleaning operation; The printing of a gas body having an odor generated in the cleaning chamber due to volatilization of Screen printing apparatus comprising the blocking means which is adapted to prevent entry into the inner.   The wiping member of the upper cleaning unit and the wiping member of the lower cleaning unit each have a form as a horizontally long plate-like body, and a cleaning sheet that can be impregnated with a cleaning liquid is pressed against the tip of the wiping member so as to be pitch-feedable The screen printing apparatus according to claim 1, wherein: 3. The screen printing apparatus according to claim 1, wherein the upper cleaning unit is provided with supply means for directly supplying an appropriate amount of cleaning liquid to the upper surface of the screen plate.   3. The screen printing apparatus according to claim 1, wherein the opening of the partition wall is formed in a size and shape necessary and sufficient for the screen plate and the holding frame to pass through the opening. A screen printing apparatus.   3. The screen printing apparatus according to claim 1, wherein the blocking means includes a shutter mechanism including a shutter plate that can be moved up and down to open and close the opening of the partition and an air cylinder that moves the shutter plate up and down. A screen printing apparatus. 3. The screen printing apparatus according to claim 1, wherein the blocking unit includes an air curtain mechanism that fluidly blocks an opening of the partition wall. 4. 3. The screen printing apparatus according to claim 1, wherein the blocking unit is installed outside the casing and operates to keep the gas pressure in the cleaning chamber at a negative pressure lower than the atmospheric pressure in the printing chamber; and A screen printing apparatus comprising: an exhaust device connected to the cleaning chamber through an exhaust conduit for exhausting the gas therein . 3. The inert gas is supplied into the cleaning chamber from an inert gas supply source installed outside the casing during the cleaning operation of the screen plate. The screen printing apparatus described in 1. During cleaning operation of the screen printing plate, said Ke - from the inert gas supply source which is installed outside the single to the cleaning chamber while supplying an inert gas, smelling generated by volatilization of the supplied inert gas and the cleaning liquid 3. A mixed gas with gas is discharged outside by an exhaust device installed outside the casing and connected to the cleaning chamber via an exhaust conduit and a gas filter. The screen printing apparatus described in 1.

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