JP2944893B2 - Method and apparatus for cleaning a printing screen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cleaning a screen used for screen printing in which a solder paste or the like is placed at a predetermined position before an electronic component is mounted on an electronic circuit board. .

[0002]

2. Description of the Related Art Screen cleaning methods and apparatuses used for screen printing on electronic circuit boards are roughly classified into the following three types. One is to directly spray a liquid solvent on a back surface (hereinafter, abbreviated as a back surface) as a main front and lower surface of the screen after printing to remove unnecessary printing material that has flowed around the back surface. The second one is to clean the back surface of the synthetic paper or fabric in a roll form (hereinafter, collectively referred to as a cloth body) and wipe off unnecessary substances (hereinafter, abbreviated as “wiping”). The third one is to mainly press a thick synthetic blade against the back surface to scrape off solder particles and the like as unnecessary residues. Further, in the third printing material, two cleaning blades are combined before and after the cleaning direction, and a printing image pattern portion (hereinafter, abbreviated as printing plate) on a screen is clogged. Between the two joined blades by using compressed air or by vacuuming in some cases.

[0003] The above-mentioned conventional cleaning method or apparatus is mainly applied to a metal screen, but may be used also for a mesh screen as the definition of a printed image pattern advances. .

[0004]

The conventional methods and apparatuses for cleaning the back surface of the screen have advantages and disadvantages. For example, in the first example, it is necessary to perform post-processing of the printing material as an unnecessary residue that has dissolved in the sprayed solvent and dropped directly below the back surface, which is troublesome.
In the second method, the solvent and a small amount of oils and the like in the printing material are relatively easily removed, but minute solder particles and the like as solids tend to remain. In the third case, on the other hand, high-viscosity materials including solder at the opening of the printing plate are removed smoothly, but liquid materials are difficult to remove. Hereinafter, all the objects to be cleaned are collectively referred to as residues.

The present invention has been made in view of the above problems, and provides a cleaning method which eliminates the disadvantages of the prior art without correcting the advantages thereof, and a cleaning unit and apparatus based thereon. is there. Less than,
When simply referring to a method, a unit, or an apparatus, it refers to a method, unit, or apparatus for cleaning the back surface of a printing screen according to the present invention.

[0006]

In order to solve the above-mentioned problems, a method according to the present invention comprises the steps of: firstly, a side of a blade having a sufficiently thin blade having a rigidity not to lose the tension of a printing screen and being in contact with the back surface of the screen. The tip of which is uniformly adhered and covered in the length direction by a cloth body is used as a cleaning blade. Of course, the length of the blade, that is, the length along the screen width direction, has a size sufficiently corresponding to the screen width. The feature of this method is that the main surface of the fabric body that closely contacts and covers the blade tip can be renewed by a roller or a guide roller that presses the star shaft with a constant pitch and its vertex.

Next, the unit according to the present invention holds a loop-shaped cloth body by a guide roller in addition to the elements necessary for realizing the method described in the preceding paragraph, and also forms the apex of the star shaft and the circle of the pressing roller. It has a mechanism to clamp it on the peripheral surface. A groove or a mounting plate is provided on the side plate or the support member to support both ends of the above elements in the axial length direction. A one-way clutch to be coupled to the drive lever of the external drive means is provided at one end of the star shaft, and each of the elements is entirely
A unit is formed by connecting the side plates or the support members.

Subsequently, the unit according to the present invention is provided with means for supplying a new cloth and collecting means for the used cloth instead of the loop-shaped cloth.

In the apparatus according to the present invention, an air cylinder for raising and lowering the unit described in the preceding paragraph is provided and used as a power source for the external driving means.

[0010]

In the method according to the present invention, a sufficiently thin blade having a high rigidity and the tip end of which is covered with a soft cloth is used as a cleaning blade. The renewal of the main surface of the cloth body is performed at a constant pitch by the apex of the star-shaped shaft and the pressing roller, so that the residue can be easily and efficiently removed.

Next, in the unit according to the present invention, since the structural members to be assembled and supported can be connected to each other to implement the method embodying the method described in the preceding paragraph, the residue can be removed as a whole without selecting a partner printing apparatus. To

Subsequently, in the unit according to the present invention, the means for supplying and recovering the cloth body is provided in place of the loop-shaped cloth body described in the preceding paragraph, so that the residue can be removed for a relatively long time.

In the apparatus according to the present invention, when the air cylinder for elevating and lowering the unit is lowered, the one-way clutch provided at one shaft end of the star shaft operates by using the movement as an external drive source. The shaft is rotated by a predetermined pitch, whereby the main surface of the screen back surface cleaning cloth covering the cleaning blade is updated. Therefore, when the air cylinder raises the unit and the blade touches the screen back,
The cloth body that closely adheres and covers it is always new.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention will be described below based on embodiments with reference to the drawings. FIG. 1 is a conceptual drawing for explaining the structure and function of a cleaning method according to the present invention. The cleaning blade, which is perpendicular to the direction of cleaning and acts most directly on residue removal, and its screen back side. This means a cross-sectional view of a main part configuration viewed from a length direction which is common to a cloth or the like covering the front end. In the figure, the arrow S indicates the back surface of the screen to be cleaned, C indicates the cleaning direction, 1 indicates a star-shaped shaft, 2 indicates the cloth body (P) with the apex of the shaft and its circumferential surface. ), A guide roller 3 for holding P to have a certain tension and guiding its movement, and a length 4 for covering the width of the area to be cleaned on the rear surface of the screen and 0.1 mm. Has a thickness of at most about 0.2 mm and
, A cleaning blade of high rigidity (for example, made of steel plate) having a width of several mm to several tens of mm, and 5 represents a holder for the blade. Note that reference numeral d denotes a pitch of 1, and a numeral as a suffix of 3 denotes a number, and illustration of a pressing means for pressing 2 toward 1 and a one-way clutch attached to one end of 1 are omitted. . Although FIG. 1 shows that the star-shaped shaft (1) rotates clockwise and the cloth body (P) is sent counterclockwise, it is needless to say that the directions may be opposite to each other. Further, although the degree of adhesion of P to 4 is very loose in the figure, it is a result of making the illustration easier to understand, and in fact, it is uniformly adhered to the width of the tip required for cleaning. . There is no particular limitation on the inclination of S4 to S, but it is desirable that the inclination is slightly forward in the direction of C as shown in the figure. For d,
It means the shortest distance between the adjacent vertices of 1 and the length of P sent by one rotation between the vertices and the peripheral surface of 2 is of course larger than this. . Further, with respect to the pressing means (2), which is not shown in the drawing, the pressing plate attached to the tip of the spring is extended to both left and right ends or the center so that the pressing plate is uniformly pressed along the axial length. What is necessary is just to slidably press. in short,
The essence of this method is a state in which the tip of a rigid blade of an ultra-thin blade of at most about 0.2 mm is closely adhered and covered with a cloth body,
It is pressed against the back surface of the screen as a residue removal target, and the above-mentioned coated surface is updated at each step of cleaning.

FIG. 2 is a cross-sectional view of a main part structure for explaining the structure and function of a cleaning unit according to the present invention, viewed from the same direction as in FIG. The meaning of each code / symbol is exactly the same as in FIG. However,
G is a groove provided in the side plate or the support member for setting the component 1 or 3, and is formed by connecting and assembling the side plate or the support member at both ends in the axial direction of each component. It is represented by an arrow U and forms a kind of unit.
The function of each element is, of course, the same as that described in the previous section. Regarding the illustration of the one-way clutch attached to one end of 1 and the pressurizing means for 1 and the specific example thereof,
This is as described in FIG. The meaning of the subscripts (1 to 3) of G also indicates only that it corresponds to the number of shafts and rollers. In short, the unit (U) is a portable unit as a whole, and can be mounted as a cleaning unit on the back surface of the screen of the screen printing apparatus via a mounting tool or a support tool without selecting a printing apparatus to be mounted. It is.

Instead of the loop-shaped P shown in FIG. 2, for example, one provided with a new P supplying means and a used collecting means by removing one guide roller (3 _-1 ) shown in FIG. Similarly, it can be used as a unit.

FIG. 3 is a cross-sectional view of a main part structure for explaining a mechanism in which the unit illustrated in FIG. 2 and described in the preceding section is actually operated by a driving source provided outside the unit. 6 is an air cylinder attached to the support base (B), 7 is a support plate for supporting the unit (U) via a transmission rod 8, 9 is a connecting rod, 10 is a drive lever, and 11 is a drive lever. Indicates that the one-way clutch, which is omitted in FIGS. 1 and 2, is attached to one end of the star shaft. From the arrangement of the drive lever with respect to one end of the star shaft in U, FIG. 3 is also known to be a cross-sectional view as viewed from the same direction as FIGS. All the elements shown in FIG.
This is an essential element constituting the device according to the present invention. That is,
The operation is as follows. When the air cylinder (6) is lowered, the unit (U) is lowered via the support plate (7) and the transmission rod (8). Leave S. While the above-described lowering operation to the predetermined position is completed, the drive lever (10) is operated via the connecting rod (9), and the star shaft is rotated by a constant pitch via the one-way clutch (11). . As described with reference to FIGS. 1 and 2, in this process, the main surface of the cloth (P) covering the cleaning blade is updated. Then, in the next ascent operation, the shaft remains fixed from the mechanism 11 and therefore P is not transferred, which contributes to the removal of S residue as an update surface. That is, the whole shown in FIG. 3 is the reason of the apparatus of the present invention.

In addition to the above embodiments, various configurations and structures are allowed without departing from the gist of the present invention. In particular, the present invention is not limited to the drawings and the like of the above embodiments. Absent. For example, the present invention is not subject to any restrictions on the presence or absence of the provision of the solvent supply means for impregnating the solvent for residue removal into the above-described wiping cloths and the presence of the solvent, and therefore, The illustration is omitted in each drawing.

[0019]

As will be easily understood from the above description, the present invention has the following effects in screen printing.

In the cleaning method according to the present invention,
The tip of the ultra-thin blade rigid blade, which is directed toward the back surface of the screen, is closely adhered and covered with a cloth or the like including synthetic paper, and is used as a cleaning blade for the back surface of the screen. All residues are removed smoothly. And since the said cloth body is renewed for every one process of cleaning,
The cleaning is performed efficiently.

The cleaning unit according to the present invention comprises:
The advantages described in the preceding paragraph can be exhibited, and because of the convenience of unitization, it can flexibly cope with various printing apparatuses and can be used.

In the cleaning device according to the present invention, an air cylinder is used as a drive source provided outside the unit, so that the entire cleaning unit is moved up and down so that the cleaning blade contacts and separates from the back surface of the screen. The blade is closely attached to each of the separated surfaces.
Since the main surface of the coated fabric body is renewed, cleaning is efficiently performed, and a good printing result is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing an embodiment of a cleaning method.

FIG. 2 is a cross-sectional view of a main part configuration showing an embodiment of a cleaning unit.

FIG. 3 is a cross-sectional view of a main part of a cleaning device according to an embodiment.

[Explanation of symbols]

1 star shaft 2 pressing roller 3 _{-1, 3 -2, 3 -3} guide roller 4 blade 5 holder 6 air cylinder 7 the support plate 8 transmission rod 9 connecting rod 10 drive lever 11 one-way clutch C cleaning direction S screen P Fabric type G Groove U Unit d Pitch

Claims (4)

(57) [Claims] 1. A fixed-shaft star-shaped shaft having a one-way clutch at one end of a shaft, a pressing roller capable of pressing a vertex of the shaft on its cylindrical peripheral surface, a pressing means for the roller, and cleaning of an ultrathin blade. A print comprising a blade and a plurality of guide rollers, sandwiched between the apex of the shaft and the peripheral surface of the pressing roller, and guided and held by the rollers so as to be able to adhere and cover the surface of the blade tip. The main surface of the cloth for wiping the screen back side is configured to be updated each time the shaft rotates by an angle corresponding to the pitch of the star shaft, and the updated surface is passed through the blade tip. And cleaning the printing screen by pressing against the back of the screen. 2. A constant-pitch star-shaped shaft having a one-way clutch at one end of a shaft, a roller capable of pressing the apex of the shaft on its cylindrical surface, a pressing means for the roller, and an ultra-thin blade. A cleaning blade, a plurality of guide rollers, a loop-shaped printing screen cloth for wiping the back surface of the printing screen, and a side plate or a support member provided with grooves or mounting plates for supporting both ends in the axial direction of each of the above elements; By connecting a drive lever of an external drive means to the one-way clutch, based on the mechanism for renewing the cloth body according to claim 1, the cloth body main surface is configured to be renewable. Printing screen cleaning unit. 3. A supply means capable of supplying a novel cloth for wiping the back surface of a printing screen in place of a loop-shaped cloth, and a collecting means capable of collecting used cloth. The cleaning unit for a printing screen according to claim 2. 4. The claims 2 to in an air cylinder and the cleaning unit mounted on the support base capable of lifting the cleaning unit according to claim 2 or 3 via the cleaning unit and the support plate and the transmission rod 3, wherein A drive lever coupled to a one-way clutch attached to the shaft end of the star shaft, a connecting rod connecting the support plate and the drive lever, and a drive means provided outside the unit; Each time the cleaning unit is moved up and down by the air cylinder for moving the tip of the cleaning blade of an ultra-thin blade closely contacted and covered with a cloth body to the back side of the printing screen, the cloth body A cleaning device for a printing screen configured to update a main surface of the printing screen.