JPH06122190A - Method and apparatus for cleaning printing screen - Google Patents

Abstract

PURPOSE:To effectively remove the printing paste in the printing patterns of a printing screen by simultaneously performing the spraying of air on one surface of the printing screen and the suction of air from the opposite surface of the printing screen. CONSTITUTION:A cleaning sheet 3 is brought into contact with the second surface of a printing screen 1 by scraping blades 4A, 4B while air is sprayed on one surface of the printing screen by a nozzle 14 and air is sucked from the second surface of the printing screen 1 in an air suction part 11 to remove the printing paste bonded to the printing screen 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cleaning a printing screen, and more particularly to a method and apparatus for cleaning a screen in a screen printer for printing cream solder or the like on a printed circuit board or the like.

[0002]

2. Description of the Related Art Conventionally, as a screen cleaning device in this type of screen printing machine, there are a back surface wiping system shown in FIG. 8 and a back surface cleaning system shown in FIG.

In the conventional example of FIG. 8, 1 is a printing screen, which constitutes a screen mask on which a printing pattern 2 for printing a printing paste such as cream solder is formed on a printed circuit board or the like. 3A is a roll on the delivery side which is a wound body of the cleaning sheet 3, 3B is a roll on the winding side, and 4 is a scraping blade.

In the conventional example of FIG. 8, the cleaning screen 3 such as cloth or paper impregnated with a solvent is pressed against the back surface of the printing screen 1 by a scraping blade 4, and the printing screen 1 is moved as indicated by an arrow P. Then, the back side of the printing screen 1 is cleaned.

In another conventional example of FIG. 9, in addition to the configuration of FIG. 8, an air suction portion 6 having an air suction port 5 is provided, and a suction device 7 provided at another position vacuum-sucks the air suction port 5. The configuration to do is added.

In the conventional example shown in FIG. 9, a cleaning sheet 3 such as cloth or paper impregnated with a solvent is pressed against the back surface of the printing screen 1 by a scraping blade 4 while air is sucked by an air sucking section 6. Meanwhile, the printing screen 1 is moved as shown by the arrow P to clean the back surface side of the printing screen 1.

[0007]

By the way, in the conventional example of FIG. 8, the cleaning sheet 3 only on the back surface of the printing screen 1 is used.
Since it is wiped off by the method, it is difficult to remove the printing paste 8 remaining in the printing pattern 2 formed on the printing screen 1 even if the cleaning sheet 3 impregnated with the solvent that dissolves the printing paste is used. .

Further, in another conventional example of FIG. 9, a cleaning sheet impregnated with a solvent adhered to the back surface of the printing screen 1 while sucking the printing paste 8 in the printing pattern 2 by air suction by the air suction portion 6 Although it is wiped off with 3, it is difficult to remove the stickiness of the paste in the print pattern 2, and the apparatus becomes large in size when the suction force is increased.

In both of the conventional examples shown in FIGS. 8 and 9,
The removal of the paste in the print pattern becomes insufficient, which causes a problem of impairing continuous printability.

The applicant of the present invention has filed Japanese Patent Application No. 3-2163.
No. 4 proposes a method and an apparatus for cleaning a screen in a screen printing machine. However, the construction of Japanese Patent Application No. 3-216634 also wipes the lower surface of the printing screen with a cleaning sheet. Had the same problem with.

In view of the above points, the present invention effectively blows air to one surface of the printing screen and sucks air to the opposite surface at the same time to effectively apply the printing paste in the printing pattern of the printing screen. It is an object of the present invention to provide a method and a device for cleaning a printing screen that can be removed.

[0012]

In order to achieve the above object, a method for cleaning a printing screen according to the present invention comprises a step of impregnating a cleaning sheet with a solvent and then blowing air onto the first surface of the printing screen. The solvent impregnated portion of the cleaning sheet is brought into contact with the second surface of the printing screen while sucking air from the second surface opposite to the first surface to remove the printing paste attached to the printing screen. It has a process.

Further, the printing screen cleaning device of the present invention comprises a solvent impregnating means for the cleaning sheet, an air blowing means for blowing air to the first surface of the printing screen, and a cleaning sheet for the first of the printing screens. An air suction unit having a scraping blade and an air suction port that are in contact with the second surface, which is the opposite surface to the surface, and a moving unit that moves at least one of the printing screen and the cleaning sheet.

1 and 2 show the principle of the present invention. In these figures, reference numeral 1 is a printing screen, on which a printing pattern 2 for printing a printing paste such as cream solder is formed on a printed circuit board or the like. 3A is a roll on the delivery side, which is a wound body of the cleaning sheet 3, and 3B is a roll on the winding side. An air suction unit 11 has an air suction port 12, and is equipped with scraping blades 4A and 4B adjacent to both sides of the suction port 12. A solvent discharge nozzle 13 discharges a solvent capable of dissolving the printing paste, and constitutes a solvent impregnating means for the cleaning sheet. Further, 14 is an air blowing nozzle as air blowing means, which is opposed to the air suction port 12 with the printing screen 1 interposed therebetween. A solvent receiving cover 15 that receives the solvent dripping is disposed below the solvent discharge nozzle 13.

[0015]

In the state of FIG. 1 which is the principle view of the present invention, the solvent is discharged from the solvent discharge nozzle 13 and the cleaning sheet 3 drawn from the feeding-side roll 3A is impregnated with the solvent. Then, the solvent-impregnated portion of the cleaning sheet 3 is positioned between the pair of scraping blades 4A and 4B, and the air suction portion 11 is raised to press the scraping blades 4A and 4B against the printing screen 1 as shown in FIG. Then, air is blown from the air blowing nozzle 14 onto the upper surface of the printing screen 1 as indicated by an arrow Q to print the printing paste 8 in the printing pattern 2.
Is blown off to the lower surface side of the printing screen, and air is sucked (vacuum suction) from the air suction port 12 of the air suction portion 11 as shown by arrow R to collect the blown printing paste, while At least one of the printing screen 1 and the cleaning sheet 3 is moved, and the lower surface (back surface) of the printing screen 1 is wiped off.

In the present invention, not only the printing paste (eg, cream solder and flux) attached to the back surface of the printing screen 1 can be wiped off with the cleaning sheet 3, but also printing that has entered the printing pattern of the printing screen 1 can be performed. The effect of removing the paste for use is great, and continuous printability can be improved when screen printing is performed using the printing screen after cleaning. Further, since the particles such as the printing paste are collected in the air suction portion 11 through the cleaning sheet 3, the cleaning sheet 3 also functions as a filter, and a suction device such as a suction blower connected to the air suction portion 11. There is also an advantage that the life of the filter is extended.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and apparatus for cleaning a printing screen according to the present invention will be described below with reference to the drawings.

3 to 6 show an embodiment of the present invention. In these drawings, 20 is a base, and a side frame 21 is vertically erected and fixed to the base. The side surface frame 21 rotatably supports a feeding-side roll 3A that is a wound body of the cleaning sheet 3 and a winding-side roll 3B that winds up the used cleaning sheet 3. Examples of the cleaning sheet 3 that can be used here include cotton cloth, synthetic fiber cloth (for example, product name: Benliese manufactured by Asahi Kasei Co., Ltd.), long-fiber non-woven fabric, and the like.

As shown in FIG. 6, the feeding side roll 3A
Is wound around a pipe 22A with a flange,
One end of A is fitted to the end of the drive shaft 24A attached to the side frame 21 by the bearing 23A, and the other end is axially supported by the side frame 21 on the opposite side and biased by the compression spring 25A. 26A is fitted. Similarly, the winding side roll 3B is wound around the flanged pipe 22B,
One end of the pipe 22B has a bearing 23B on the side frame 21.
Is detachably fitted to the end portion of the drive shaft 24B attached at the other end, and the other end is detachably fitted to the idling fitting member 26B pivotally supported by the side frame 21 on the opposite side and biased by the compression spring 25B. is doing.

A torque motor 30 for applying a predetermined tension to the cleaning sheet 3 delivered from the delivery roll 3A is fixed on the base 20, and a belt wheel 31 is fixed to the rotary shaft of the torque motor 30. There is.
Further, a belt wheel 32A is fixed to a drive shaft 24A which is interlocked with the feeding side roll 3A, and a timing belt 33A is wound around the belt wheels 31 and 32A.

A winding motor (for example, a motor with a speed reducer) 35 is fixed on the base 20 for winding the cleaning sheet 3, and a belt wheel 36 is fixed to the rotation shaft of the winding motor 35. There is. Further, a belt wheel 32B is fixed to the drive shaft 24B that is interlocked with the winding side roll 3B, and a timing belt 33B is wound around the belt wheels 36 and 32B. Therefore, the cleaning sheet 3 can be wound up by rotating the drive shaft 24B counterclockwise by the winding motor 35 and rotating the flanged pipe 22B interlocking with the drive shaft 24B counterclockwise. At that time, the pipe 22A with the flange on the feeding side by the torque motor 30
Since a weak torque in the reverse rotation direction is applied to the cleaning sheet 3, it is possible to prevent the cleaning sheet 3 from loosening.

As shown in FIGS. 3 and 6, the air suction unit 1
Reference numeral 1 denotes a thin square pipe slider 40 having an upper end opening serving as an air suction port 12, and the square pipe slider 4
Scraping blades 4A and 4B fixed along the longitudinal side faces of the upper end of 0, and a plate member 41 for closing the gap between both ends of the scraping blades 4A and 4B to enhance the air suction effect as shown in FIG. have. A slider receiver 42 for slidably supporting the slider 40 in the vertical direction is fixed on the base 20, and a hose connection port 43 is fixed to the slider receiver 42. The internal space of the slider receiver 42 communicates with the inside of the slider 40 and the inside of the hose connection port 43, and is substantially airtightly sealed. Hose 4 connected to each hose connection port 43
Reference numeral 4 is connected to a suction device such as a suction blower (for example, pressure 1000 mm water column, suction amount 2 m ³ / min) via a relay part 45 and a hose 46 on the base. Therefore, when the suction device is operated, a negative pressure is generated in the air suction port 12 between the scraping blades 4A and 4B.

An air cylinder 50 for raising and lowering the air suction portion 11 is fixed on the base 20, and a tip of a piston rod 51 of the air cylinder 50 is connected to a connecting fitting 52 fixed to the slider 40. It is fixed.

A solvent discharge nozzle 13 for discharging a solvent is attached between the side frames 21 upward. The solvent discharge nozzle 13 has a hole 1 for solvent discharge at the top of the pipe.
3A is opened. Below the solvent discharge nozzle 13, a gutter-shaped solvent receiving cover 1 for receiving the drool of the solvent is provided.
5 are provided. As a solvent, a screen frame 80
It is possible to use a material that can dissolve the printing paste attached to the printing screen 1 stretched over the substrate, such as isopropyl alcohol.

The cleaning sheet 3 pulled out from the feeding side roll 3A passes through the guide roller 55 rotatably supported by the side frame 21 and passes through the solvent discharge nozzle 13.
Of the guide roller 5 rotatably supported by the side frame 21.
6 and the pinch roller 57, and is wound by the winding side roll 3B. Here, the rotation amount detecting impeller 58 is fixed coaxially with the guide roller 56, and the rotation amount detecting optical sensor 59 is provided on the side surface via the mounting metal fitting 60 so as to be located at a position facing the blade of the impeller 58. It is fixed to the frame 21. An intermediate portion of the pinch roller 57 is pivotally attached to the upper end of a mounting arm 61 pivotally supported by the side frame 21. The mounting arm 61 is biased by a spring means (not shown) in such a direction that the pinch roller 57 is pressed against the guide roller 56.

Further, as shown in FIG. 3, in order to dry the printing screen 1, a drying air blowing nozzle 65 for blowing air upward is attached to the left end of the side frame by a supporting member 66. The drying air blowing nozzle 65 has an air blowing hole formed in the upper portion of the pipe.

As shown in FIG. 4, a rotary actuator 72 is fixed to a support block 71 located above the printing screen 1, and a rotary arm 72 is fixed to the drive shaft of the rotary actuator 72. The air blowing nozzle 14 is fixed. The air blowing nozzle 14 is formed by forming an air blowing hole in a pipe. The rotary actuator 72 is used to rotate the air blowing nozzle 14 by 90 degrees to the imaginary line position in FIG. 4 so as not to interfere with the replacement of the printing screen 1 or the like.

FIG. 7 shows a moving means for supporting and horizontally moving the screen frame 80 on which the printing screen 1 is stretched. In this figure, 81 is a side wall portion perpendicular to the base, and 82 is slidable in the horizontal direction (lateral direction, here, the direction of arrow S or the opposite direction) with respect to the side wall portion 81. It is a horizontal slide frame. The lateral slide frame 82 can perform an operation of transferring the screen frame 80 from the cleaning position P1 to the actual printing upper position (upper position of the screen frame position when performing the screen printing operation) P2, or vice versa. It also has a function of reciprocating the screen frame 80 over the cleaning range of the printing screen 1 by the cleaning sheet 3. The lateral slide frame 82 has a slider 90 slidably fitted in a slide groove (slide rail) provided on the side wall 81 side integrated with the outer surface, and holds the screen frame 80 on the inner surface. Two pairs of screen frame holding mechanisms 91 that face each other are provided. The screen frame holding mechanism 91 has a fitting member (clamper) 93 fitted to the side surface of the screen frame 80 fixed to the end of the expanding and contracting rod of the air cylinder 92 fixed to the lateral slide frame 82. That is, the screen frame holding mechanism 91 holds the screen frame 80 when the rod of the air cylinder 92 extends, and releases the screen frame 80 when the rod contracts. On the other hand, the timing belt 9 is attached to the pulley 95 pivotally supported by the side wall 81.
6, the timing belt 96 is fixed to the belt fixing portion 97 of the lateral slide frame 82. The lateral drive of the lateral slide frame 82 is executed by running the timing belt 96 by a predetermined amount by the timing belt running means (not shown), and the lateral slide frame 82 moves between the cleaning position P1 and the actual printing upper position P2. You are free.

In the configuration of the above embodiment, first, as shown in FIG. 5, the air suction portion 11 is set to the lowered position, the printing screen 1 and the screen frame 80 are set to the standby position shown by the solid line in FIG. The air blowing nozzle 14 is driven to the air blowing position shown by the solid line in FIG. At this time, the air suction by the air suction unit 11 and the air blowing by the air blowing nozzle 14 are stopped.

Then, the solvent is discharged from the solvent discharge nozzle 13 to impregnate the cleaning sheet 3 drawn from the roll 3A on the delivery side with the solvent (this solvent impregnation step may be omitted depending on the operation mode).

After that, when the air suction portion 11 is set to the raised position as shown in FIG. 3, the guide roller 56 and the air suction portion 11 are moved.
As a result of the longer distance between the scraping blades 4A, the solvent-impregnated portion of the cleaning sheet 3 has a pair of scraping blades 4A.
It is automatically located between A and 4B. When the air suction portion 11 reaches the upper limit position, the scraping blades 4A and 4B are pressed against the lower surface of the printing screen 1 via the solvent-impregnated portion of the cleaning sheet 3 as shown in FIG.

Then, air suction in the direction of arrow R by the air suction portion 11 on the lower side of the printing screen 1 and air blowing in the direction of arrow Q by the air blowing nozzle 14 located above the printing screen 1 and facing the air suction portion 11. At the same time, the screen frame 80 to which the printing screen 1 is fixed is driven in the direction of arrow S by the moving means shown in FIG. As a result, by blowing air from the air blowing nozzle 14 onto the upper surface of the printing screen 1, the printing paste in the printing pattern is blown to the lower surface side of the printing screen, and the air from the air suction port 12 of the air suction portion 11 is blown. The operation of wiping the lower surface (back surface) of the printing screen 1 with the cleaning sheet 3 can be executed while collecting the printing paste blown off by suction (vacuum suction). The printing screen 1 can be dried by blowing air from the drying air blowing nozzle 65.

When the lower surface wiping of the printing screen 1 is completed, the operations of the air suction unit 11 and the air blowing nozzle 14 are stopped, and the air suction unit 11 returns to the lowered position. afterwards,
The take-up motor 35 is operated by the designated pitch of the rotation amount detecting impeller 58, and the cleaning sheet 3 is slightly taken up by the take-up side roll 3B driven by the take-up motor 35 so that the surface of the new cleaning sheet 3 is removed. Get out and prepare for the next cleaning. The appropriate winding amount of the cleaning sheet 3 is determined by detecting the rotation of the impeller 58 by the optical sensor 59 and by rotating the winding motor 3 described above.
It can be realized by controlling the operation time of 5. This completes one cleaning operation.

After that, the above-described cleaning operation can be executed again without running the printing screen 1 in the direction opposite to the arrow S. If necessary, the printing screen 1 may be reciprocated a plurality of times to perform the cleaning operation.

[0035]

As described above, according to the method and apparatus for cleaning a printing screen of the present invention, when wiping the printing screen with the cleaning sheet, air is blown to one surface of the printing screen and the opposite surface ( By simultaneously performing air suction on the contact surface of the cleaning sheet), the printing paste in the printing pattern of the printing screen can be effectively removed. As a result, continuous printability can be improved when screen printing is performed using the printing screen after cleaning.

[Brief description of drawings]

FIG. 1 is a principle view of a method and apparatus for cleaning a printing screen according to the present invention in a state where an air suction portion is lowered.

FIG. 2 is a principle diagram of an ascending state of the air suction unit.

FIG. 3 is a front sectional view showing a specific example of the present invention.

FIG. 4 is a front sectional view showing the upper portion of the embodiment.

FIG. 5 is a front cross-sectional view when the air suction unit is in the lowered position in the embodiment.

FIG. 6 is a plan view of the embodiment.

FIG. 7 is a plan view showing a moving unit of a screen frame on which a printing screen is stretched in the embodiment.

FIG. 8 is a schematic view showing a conventional example.

FIG. 9 is a schematic view showing another conventional example.

[Explanation of symbols]

 1 Printing Screen 2 Printing Pattern 3 Cleaning Sheet 4, 4A, 4B Scraping Blade 8 Printing Paste 11 Air Suction Part 12 Air Suction Port 13 Solvent Discharge Nozzle 14 Air Spray Nozzle 20 Base 30 Torque Motor 35 Winding Motor 40 Square Pipe-shaped slider 42 Slider receiver 50 Air cylinder 65 Air blowing nozzle 80 Screen frame

Claims (5)

[Claims] 1. A cleaning sheet is brought into contact with the second surface of the printing screen while blowing air onto the first surface of the printing screen and sucking air from the second surface opposite to the first surface. A method for cleaning a printing screen, characterized in that the printing paste attached to the printing screen is removed. 2. A solvent for the cleaning sheet after the cleaning sheet is impregnated with the solvent, while blowing air onto the first surface of the printing screen and sucking air from the second surface opposite to the first surface. A method for cleaning a printing screen, wherein the impregnated portion is brought into contact with the second surface of the printing screen to remove the printing paste attached to the printing screen. 3. An air blowing unit for blowing air to the first surface of the printing screen, and a scraping blade and an air suction port for bringing a cleaning sheet into contact with the second surface of the printing screen, which is opposite to the first surface. An air suction unit having
A cleaning device for a printing screen, comprising: a moving unit that moves at least one of the printing screen and the cleaning sheet. 4. The apparatus for cleaning a printing screen according to claim 3, further comprising solvent impregnating means for impregnating the cleaning sheet with a solvent. 5. The cleaning device for a printing screen according to claim 3, wherein the scraping blades are provided on both sides of the air suction port.