JP2000085103A - Method and device for printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for printing by which in the snap off process of printing paste filled in the through-holes of a screen mask, snap off of printing paste is surely performed even in the high aspect conditions and transfer failure is reduced. SOLUTION: As shown in (c), a screen mask 4 is scraped by a squeezee 7 and cream solder 1 used as printing paste is moved and also filled into through-holes formed in the screen mask 4 abutting on a printed circuit substrate 2 used as a body to be printed. As shown in (d), gas G is blown to the cream solder 1 filled into the through-holes 5 of the screen mask 4 and while pushing out the cream solder 1, the screen mask 4 is separated from the printed circuit substrate 2. As shown in (e), the cream solder 1 is transferred on the printed circuit substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method and a printing apparatus for transferring a printing paste to a printing material through a through hole formed in a screen mask.

[0002]

2. Description of the Related Art As a conventional printing apparatus, for example, there is an apparatus which transfers cream solder as a printing paste onto lands of a printed circuit board in order to mount electronic components on a printed circuit board as a printing medium. .

In this printing apparatus, as shown in FIG. 10A, a screen mask in which through holes 5 are formed in accordance with a predetermined printing pattern so as to correspond to lands of a printed circuit board 2 to which cream solder 1 is to be transferred. The screen mask 4 is scraped with a squeegee 7 while the cream solder 1 is in contact with the printed circuit board 2 so that the cream solder 1 is printed on the land of the printed circuit board 2. 5, and the filled cream solder 1 is transferred to the land 3 of the printed circuit board 2.

Here, as a conventional printing method, for example,
A flat-plate stencil (screen) printing method for transferring the cream solder 1 onto the lands 3 of the printed circuit board 2 will be specifically described.

In this flat plate stencil printing method, FIG.
As shown in (a) and (b), a screen mask (metal mask) 4 in which a through hole 5 is formed according to a predetermined printing pattern so as to correspond to the land 3 of the printed circuit board 2 to which the cream solder 1 is to be transferred. Is placed at a predetermined position on the printed circuit board 2 and brought into contact therewith, and the cream solder 1 is supplied to one end on the screen mask 4.

Then, as shown in FIGS. 10 (c) and 11 (a), the squeegee 7 moves the cream solder 1 from one end of the screen mask 4 in a predetermined moving direction X, thereby obtaining the state shown in FIG. As shown in (1), the cream solder 1 is filled in the through holes 5 of the screen mask 4.

Next, as shown in FIGS. 10 (d) and 11 (c), the screen mask 4 is removed from the printed circuit board 2, and as shown in FIGS. 10 (e) and 11 (d), The cream solder 1 filled in the through hole 5 of 4 is transferred onto the land 3 of the printed circuit board 2 to form a cream solder layer 8 on the land 3 of the printed circuit board 2.

[0008]

However, in the conventional printing method, as shown in FIG. 11C, when the screen mask 4 is separated from the substrate 2, the outer peripheral portion of the cream solder 1 is pulled by the screen mask 4. FIG. 11 (d)
As shown in (1), there is a problem that the shape of the cream solder layer 8 after transfer is not stable. The instability of the transfer shape is affected by various factors such as the physical properties of the cream solder 1, the tension of the screen mask 4, and the speed at which the screen mask 4 separates from the printed circuit board 2. Although the cream solder layer 8 shown in FIG. 10E is shown in a rectangular shape, this shape shows an ideal case, and the cream solder layer 8 is actually shown in FIG. 11D. It has a collapsed shape like this.

Further, with the recent trend toward smaller and thinner electronic devices, there is an increasing demand for smaller electronic devices and finer mounting patterns in the circuit board manufacturing process.
Similarly, in the printing process of the cream solder 1, more and more,
Transfer with a high aspect ratio under severe printing conditions is required. The aspect ratio is a ratio of the side area of the through hole 5 to the opening area, and indicates the degree of difficulty of transfer. Under the condition where such a high aspect ratio is required, as shown in FIG. 11D, not only the above-mentioned unstable phenomenon of the transfer shape but also most of the cream solder 1 is formed in the through hole 5 of the screen mask 4. There is a problem that a transfer failure which remains on the inside and is not sufficiently transferred to the printed circuit board 2 is caused.

It is an object of the present invention to provide a printing method and a printing apparatus, in which a printing paste is surely separated even under a high aspect condition, thereby reducing transfer failure in a printing paste separating step of a printing paste filled in a through hole of a screen mask. With the goal.

[0011]

According to the printing method of the present invention, the printing paste is moved by scratching the screen mask with a squeegee, and the printing paste is passed through the through-hole formed in the screen mask in contact with the printing medium. The printing paste is transferred to the printing medium by separating the screen mask and the printing medium while blowing and pushing out the gas to the printing paste filled and filled in the through holes of the screen mask.

According to the present invention, in the step of separating the printing paste from the printing paste filled in the through-holes of the screen mask, the printing paste can be surely separated even under a high aspect condition, and transfer defects can be reduced.

[0013]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, a printing mask is moved by scraping a screen mask with a squeegee, and a through hole formed in the screen mask which is in contact with a printing medium. A printing method in which the printing paste is filled, and the screen mask and the printing medium are separated while the gas is blown and extruded to the printing paste filled in the through holes of the screen mask to transfer the printing paste to the printing medium. In the plate separation step of the printing paste filled in the through-hole of the screen mask, the printing paste filled in the through-hole can be effectively extruded with the gas blown out from the gas outlet of the spraying means. The printing paste filled in the holes can easily release the plate, and printing can be performed even under high aspect conditions. Paste to can be stably supplied to the printing material, it is possible to transfer a good printing paste printing substrate.

According to a second aspect of the present invention, there is provided a through-hole formed in a screen mask by arranging a screen mask and a printing object in contact with each other and scraping a printing paste on the screen mask with a squeegee. The printing paste filled in the through-hole of the screen mask is blown up with gas and pushed out to push up the screen mask on the upper side in the moving direction of the squeegee so as to separate the screen mask and the printing medium from each other. The method is a printing method in which the printing paste is transferred to the printing medium, and the printing paste can be stably supplied to the printing medium even under high aspect conditions, and a good printing paste can be transferred to the printing medium. Can be.

According to a third aspect of the present invention, the screen mask and the printing medium are arranged with a gap therebetween, and the printing mask on the screen mask is scraped with a squeegee to thereby remove the screen mask from the printing medium. The screen squeegee is moved while pressing and contacting the body with a printing paste in a through-hole formed in the screen mask, and blowing and extruding gas onto the printing paste filled in the through-hole of the screen mask. This is a printing method in which the printing paste is transferred to the printing medium by separating the mask from the printing medium, and the transfer is performed with the gap between the screen mask and the printing medium being provided. Even in the case of offset printing, the same effect is obtained.

According to a fourth aspect of the present invention, the printing paste on the screen mask is scratched with a squeegee to fill the through holes of the screen mask, and the printing paste filled in the through holes is transferred to the printing medium. A printing device provided with blowing means for blowing gas onto the screen mask on the upper side in the moving direction of the squeegee, wherein the printing paste filled in the through-hole is blown by the gas of the blowing means. It can be effectively extruded by the gas blown out from the blowout port, and the printing paste filled in the through-hole of the screen mask can be easily separated from the plate.

According to a fifth aspect of the present invention, a screen mask lifting means is provided on the upper side in the moving direction of the squeegee to separate the screen mask from the printing medium in conjunction with the movement of the squeegee. According to the printing apparatus described above, a printing paste can be stably supplied to a printing medium even under a high aspect condition, and a good printing paste can be transferred to a printing medium.

According to a sixth aspect of the present invention, there is provided a forward squeegee for scraping the print paste on the forward path and a return squeegee for scraping the print paste on the return path, and the upstream side squeegee moving direction and the return path squeegee 6. The squeegee according to claim 4, wherein a spraying means is provided on each of the upstream sides in the moving direction of the squeegee.
It is not necessary to invert the squeegee and the spraying means depending on the moving direction of the squeegee, and the printing paste can be transferred on both the outward path and the return path, so that the transfer process is greatly increased. Can be shortened.

According to a seventh aspect of the present invention, the squeegee has a rear end near the front end of the squeegee inclined such that the rear end of the squeegee is located on the upper side in the moving direction of the squeegee with respect to the front end of the squeegee. The printing apparatus according to any one of claims 4 to 6, wherein a gas outlet of the blowing means is provided close to the upper side in the moving direction, and the printing paste of the screen mask is scratched with a squeegee. Immediately thereafter, gas can be blown from the gas outlet into the print paste in the through-hole.

[0020] In the invention according to claim 8 of the present invention, the spraying means is provided with a gas reservoir between an input port to which gas is supplied and the gas blowout port so that the gas is uniformly blown from the entire area of the gas blowout port. The printing apparatus according to any one of claims 4 to 7, wherein the gas is blown out from the entire area of the gas blowout port, and the gas blowout is performed for each through hole of the screen mask. The operation of aligning the mouth and blowing gas can be unnecessary.

According to a ninth aspect of the present invention, there is provided the printing apparatus according to any one of the fourth to eighth aspects, wherein the spraying means is configured such that a gas outlet thereof is brought into contact with a screen mask. The gas can be efficiently blown to the printing paste in the through-hole, and the extrusion pressure can be effectively applied.

Hereinafter, a printing method and a printing apparatus according to the present invention will be described based on specific embodiments. (Embodiment 1) A printing apparatus according to Embodiment 1 of the present invention
As shown in FIG. 1, a blowing means 6 for blowing gas G to the screen mask 4, and a printed circuit board as a printing medium in conjunction with the movement of the squeegee 7, on the upper side in the moving direction X of the squeegee 7. The screen mask lifting means 9 for separating the screen mask 4 from the screen mask 2 is provided.

The gas outlet 6a of the blowing means 6 is arranged, for example, in parallel with the squeegee 7,
Is configured to move in the movement direction X integrally with the squeegee 7. The gas G includes, for example, air.

Here, as a printing method according to the first embodiment of the present invention, for example, cream solder 1 as a printing paste is used.
Will be specifically described with reference to a flat-plate stencil (screen) type printing in which is transferred onto the land 3 of the printed circuit board 2.

First, as shown in FIGS. 1A and 1B,
The screen mask (metal mask) 4 has lands 3 of the printed circuit board 2 to which the cream solder 1 is to be transferred.
These through-holes 5 are formed in accordance with a predetermined printing pattern so that the through-holes 5 correspond to the positions of the screen mask 4. The screen mask 4 is located at a predetermined position on the printed circuit board 2 and is brought into contact therewith. At this time, in order to make the alignment between the printed circuit board 2 and the screen mask 4 more precise, the printed circuit board 2 and the screen mask 4 are aligned without any gap.

Next, as shown in FIG. 1A, the cream solder 1 is supplied to one end on the screen mask 4. Before the movement of the squeegee 7 is started, the screen mask 4 on the upper side in the moving direction X of the squeegee 7 is moved 1 mm from the substrate surface of the printed circuit board 2 by the screen mask lifting means 9 as shown in FIG. Push up to a height of about 2 mm and lift. At this time, in the portion of the screen mask 4 where the squeegee 7 exists, the screen mask 4 is pressed down by the squeegee 7.

As shown in FIGS. 1 (c) and 2 (a), the cream solder 1 on the screen mask 4 is moved from one end of the screen mask 4 in the moving direction X by scraping with a squeegee 7 while pressing the screen mask 4. And the cream solder 1 is filled into the through holes 5 of the screen mask 4. At this time, the cream solder 1 in the through hole 5 is
As shown in FIG. 2B, the upper surface of the screen mask 4 is filled.

Next, as shown in FIGS. 1 (d) and 2 (c), the cream solder 1 filled in the through-hole 5 of the screen mask 4 is blown from the gas G The squeegee 7 moves in the moving direction X
And the screen mask 4 is sequentially separated from the printed circuit board 2 from where the squeegee 7 has passed,
The cream solder 1 filled in the through hole 5 is transferred to the printed circuit board 2, and as shown in FIGS. 1 (e) and 2 (d),
A cream solder layer 8 is formed on the lands 3 of the printed circuit board 2.

Incidentally, the squeegee 7 is completely moved to the screen mask lifting means 9 located on the lower side in the moving direction X, the transfer of the printed circuit board 2 is completed, and the next printed circuit board 2 to be transferred is completed. Is set, the squeegee 7 and the spraying means 6 are turned 180 degrees in the horizontal direction, and the screen mask lifting means 9 located on the lower side is set.
Is pushed up as described above, and the squeegee 7 and the spraying means 6 are moved in the direction opposite to the moving direction X to transfer the cream solder 1 to the printed circuit board 2.

Here, the plate separation stroke and the plate separation state of the printing paste will be described. Conventional cream solder 1
3A, when the screen mask 4 filled with the cream solder 1 in the through hole 5 is separated from the printed circuit board 2 as shown in FIG. A portion of the cream solder 1 is transferred to the printed circuit board 2, but most of the cream solder 1 remains in the through holes 5 of the screen mask 4, and
Is small, and the cream solder layer 8a is greatly deformed, resulting in a poor transfer shape.

If the blowing time of the gas G by the blowing means 6 exceeds the plate separation time (screen mask thickness / plate separation speed), as shown in FIG. Although the amount of the cream solder 1 remaining in the hole 5 is reduced, the cream solder 1 from the through hole 5 is crushed, and the transfer shape of the cream solder layer 8b after the transfer is completed becomes defective.

The blowing means 6 of the first embodiment is set so that the gas blowing distance is within the thickness of the screen mask 4 with an appropriate blowing force, and as shown in FIG. If the blowing distance of the gas is within the thickness of the screen mask 4 with a suitable blowing force, the cream solder layer 8 having a good transfer shape can be obtained without crushing the cream solder 1 from the through hole 5. Specifically, the blowing means 6 blows the gas G until the gas G reaches the separation distance t1 with respect to the thickness Tm of the screen mask 4.

With this configuration, in the step of releasing the cream solder 1 filled in the through hole 5 of the screen mask 4 from the plate, the gas blown out of the cream solder 1 filled in the through hole 5 from the gas blowing port 6 a of the spraying means 6. Can be effectively extruded, and the through holes 5 of the screen mask 4
Can be easily released from the plate, the cream solder 1 can be stably supplied on the printed circuit board 2 even under a high aspect condition, and a good cream solder layer 8 can be formed. It can be transferred to the printed circuit board 2.

(Embodiment 2) As shown in FIG. 4, the spraying means 6 of the printing apparatus according to Embodiment 2 has a rear end 7a of the squeegee 7 which is larger than a front end 7b of the squeegee 7. The moving direction X of the squeegee 7 near the front end 7b of the squeegee 7 which is inclined so as to be located on the upper side of the moving direction X
A gas outlet 6a is provided in close proximity to the upper side of the gas outlet 6a, and a gas reservoir 6c is provided between the input port 6b to which the gas G is supplied and the gas outlet 6a, so that the gas G is uniformly distributed from the entire area of the gas outlet 6a. Is configured to blow out.

The printing apparatus according to the second embodiment has the same configuration as that of the first embodiment except for the spraying means 6 of the first embodiment. Detailed description is omitted.

As shown in FIG. 4A, the spraying means 6 is provided close to the upper side of the moving direction X of the squeegee 7, and has a gas outlet 6a and a gas reservoir 6c inside. Block 6e provided for the gas and gas reservoir 6c
And a plurality of input ports 6b for inputting the data to the input port.

FIG. 4B shows a state before the squeegee 7 is attached to the spraying means 6. This spraying means 6
Is longitudinally symmetrical, for example, so only the left side is shown here.

The longitudinal length 6d of the gas outlet 6a
Corresponds to the width of a general-purpose printed circuit board, for example,
It is 250 mm. The gas G from each input port 6b is once stored in the gas reservoir 6c, and the gas outlet 6c is formed by the gas reservoir 6c.
The gas G is blown out evenly from the whole area of a.

The gas reservoir 6c has a cylindrical shape, and both ends in the longitudinal direction are sealed by a sealing member 6f.
With this configuration, the gas G can be blown from the gas blowing port 6a to the cream solder 1 in the through hole 5 immediately after the cream solder 1 on the screen mask 4 is scratched by the squeegee 7.

The gas outlet 6a of the blowing means 6
Gas can be blown out evenly from the entire area of the screen mask 4.
It is not necessary to perform the operation of aligning and spraying the gas G.

(Embodiment 3) As shown in FIG. 5, the spraying means of a printing apparatus according to Embodiment 3 has an elastic body 6g provided around a gas outlet 6a.

The elastic body 6g is made of, for example, urethane rubber having a shear hardness of about 60 ° to 80 °. The printing apparatus according to the third embodiment is the same as the printing apparatus 6 according to the second embodiment except that an elastic body 6g is added. A detailed description of is omitted.

In the step of releasing the cream solder 1 filled in the through hole 5 of the screen mask 4, the squeegee 7 scratches the screen mask 4 and fills the through hole 5 with the cream solder 1. Gas outlet 6a
Is brought into contact with the screen mask 4 and the gas G is blown in a state where the spray area is sealed.

With this configuration, the gas G is sprayed only within the intended range of the screen mask 4 and does not leak to the outside, so that the gas G can be efficiently sprayed onto the cream solder 1 in the through hole 5. Extrusion pressure can be applied more effectively than when the spray area is not sealed.

In the third embodiment, the gas outlet 6
Although the elastic body 6g provided on the screen mask 4 is in contact with the elastic body 6g, even when the gas outlet 6a is directly contacted with the screen mask 4, it is slightly inferior to the case where the elastic body 6g is provided. Extrusion pressure can be applied.

(Embodiment 4) As shown in FIG. 6A, a printing apparatus according to Embodiment 4 includes a forward squeegee 7c for scraping cream solder 1 as a printing paste in a forward path A,
A return squeegee 7d for scraping the cream solder 1 on the return path B is provided, and spraying means 6 is provided on each of the upper side in the moving direction of the forward path squeegee 7c and the upper side in the moving direction of the return path squeegee 7d. .

In the printing apparatus shown in FIG. 6A, the forward solder squeegee 7c transfers the cream solder 1 to the printed circuit board 2 while moving toward the forward travel A, and the backward travel squeegee 7d moves toward the backward travel B. When the cream solder 1 is transferred to the printed circuit board 2 while moving toward, the screen mask lifting means 9 on the upper side in the moving direction of the return path B is pushed up.

The printing apparatus according to the fourth embodiment is the same as the printing apparatus according to the second embodiment except that the squeegee 7 and the spraying means 6 according to the second embodiment are provided for the forward path and the return path. Therefore, a detailed description of the parts other than the squeegees 7c and 7d and the blowing means 6 will be omitted.

For example, the forward squeegee 7c and its blowing means 6 are configured as shown in FIG. 6 (b). Here, the plate separation stroke and the plate separation state of the printing paste will be described.

The spraying means 6 of the first embodiment is set so that the gas blowing distance is within the thickness of the screen mask with an appropriate blowing force, and as shown in FIG. If the gas blowing distance by the blowing force is within the thickness of the screen mask, the cream solder layer 8 having a good transfer shape can be obtained without the cream solder 1 from the through hole 5 being crushed. Specifically, the blowing means 6 blows the gas G until the gas G reaches the separation distance t1 with respect to the thickness Tm of the screen mask 4.

Here, the relationship between the gas blowing distance when the thickness Tm of the screen mask 4 is 0.12 mm, the aspect ratio indicating the degree of difficulty of transfer, and the target print pattern will be described.

In the conventional step of separating the cream solder 1 from the plate,
As shown in FIG. 7, for example, if the aspect ratio is up to about 1.5 as shown in FIG.
Since the transfer volume ratio of the conventional method is 50% or more, good transfer of the cream solder 1 is possible even in the conventional method, but in the transfer with a high degree of difficulty such that the aspect ratio exceeds 1.5, the conventional method is used. The transfer volume ratio becomes 50% or less, and it is impossible to perform good transfer of the cream solder 1 by the conventional method. The transfer volume ratio indicates the ratio of the volume of the opening of the screen mask 4 to the volume (transfer volume) of the cream solder 1 transferred to the printed circuit board 2 and is used as an index for determining the quality of printing.

Therefore, in the transfer with a high degree of difficulty such that the aspect ratio exceeds 1.5, the spraying unit 6 performs the transfer until the aspect ratio apparently becomes about 1.5 or less. Optimally, plate separation is performed using a controlled plate separation unit. From these, FIG.
As shown in (c), it is understood that it is necessary to precisely control the separation distance t1 of the screen mask 4 so as to blow the gas G from the gas outlet 6a until the gas G reaches the separation distance t1. The gas blowing distance shown in FIG. 7 is a distance for reducing the aspect ratio to 1.5 or less when the thickness Tm of the screen mask 4 is 0.12 mm.

From this, as shown in FIG.
Based on (Equation 1), (Equation 1) and (Equation 2) show calculation equations for calculating specific dimensions when providing a predetermined clearance between the gas outlet 6a and the screen mask 4.

Hn = Ln · tan (tan ⁻¹ (H / L)) (Equation 1) Hn <Tm (Equation 2) Note that H is the distance between the screen masks 4 that are separated from each other. The clearance between the pressing portion of the blowing means 6 and the screen mask 4, the distance L from the pressing portion of the squeegee 7c to the pressing portion of the blowing means 6, Ln is the width of the gas outlet 6a, and Ln is the gas outlet. Tm indicates the thickness of the screen mask 4 and the clearance between the screen mask 4 and 6a.

Each dimension is set so as to satisfy Hn <Tm shown in (Equation 2). As shown in FIG. 6A, the lifting stroke of the screen mask lifting means 9 is
For example, the separation distance t1 is precisely controlled by making the squeegee 7c and the screen mask 4 sufficiently long to about 2 mm, providing a clearance of about 0.2 mm between the squeegee 7c and the screen mask 4, and pressing the spray area of the screen mask 4 by the gas blowing port 6a. can do.

As shown in FIG. 7, from the results of the experiments so far, the diameter of the through hole 5 in the print pattern was φ0.2 mm.
In the following fine pattern portion, the transfer volume ratio after the printing process in the conventional method was 20% or less with respect to the volume of the through hole 5 of the screen mask 4. If the pressure of pushing out the gas G from 6a is about 0.05 to 0.07 kgf / cm ² ,
It has been found that it is improved to about 0%. In other words, in order to improve the plate separation property, the spraying means is controlled so that the input gas and the flow rate to the input port 6b of the spraying means 6 are controlled by means such as having a database in advance so that a predetermined blowing pressure can be obtained. 6.

FIG. 8 shows the correlation between the air pressure and the flow rate when the distance between the gas outlet 6a and the screen mask 4 is 1 mm, 2 mm, and 3 mm. As the distance between the gas outlet 6a and the screen mask 4 is smaller, the pressure is higher, and the blowing efficiency for separating the plate is improved. For example, in the case of the cream solder 1, the necessary air pressing pressure is 0.05 to 0.07 kgf / cm ² , and the distance between the gas outlet 6a and the screen mask 4 is 1 mm.
In this case, the air flow rate needs to be about 230 Nl / min. Further, the air pressing pressure is greatly affected by the clearance Hn between the gas outlet 6a and the screen mask 4 and the flow rate of air flowing out of the gas outlet 6a. The required air pushing pressure (0.0
In order to obtain 5 to 0.07 kgf / cm ² ), the clearance Hn is preferably set to about 0.2 mm or less.

As shown in FIG. 7, when the opening size φW of the screen mask 4 is 0.4 to 1.0 mm, the gas blowing distance is 0 mm, but the aspect ratio is 1.5 or less. Therefore, transfer can be sufficiently performed without using the present invention. For example, when the opening size φW of the screen mask 4 is 0.3 mm, the gas spraying distance is set to 0 with the state filled with the cream solder 1 to 7.5 μm while the gas is blown while the plate is separated.

With this configuration, in the step of releasing the cream solder 1 filled in the through hole 5 of the screen mask 4 from the plate, the gas blown out of the gas blowing port 6 a of the spraying means 6 is supplied with the cream solder 1 filled in the through hole 5. Can be effectively extruded, and the through holes 5 of the screen mask 4
Can be easily released from the plate, the cream solder 1 can be stably supplied on the printed circuit board 2 even under a high aspect condition, and a good cream solder layer 8 can be formed. It can be transferred to the printed circuit board 2.

In the printing apparatus according to the fourth embodiment, the cream solder 1 can be transferred between the forward path A and the backward path B. Therefore, as in the printing apparatus according to the first embodiment, the squeegee 7 is moved in the moving direction X of the squeegee 7. And the spraying means 6 do not need to be reversed, and the cream solder 1 can be transferred on both the forward path A and the backward path B, so that the transfer step can be greatly shortened.

In each of the above embodiments, the screen mask 4 is a flat plate stencil printing in which the screen mask 4 is brought into contact with the printed circuit board 2 as a printing medium. However, as shown in FIG. 9, FIG. Screen mask lifting mechanism 9 shown in
In place of this, the same effect can be obtained even when an offset printing method in which the transfer is performed while positioning is performed with a gap between the screen mask 4 and the printed circuit board 2 is adopted. In the printing apparatus shown in FIG. 9, the cream solder 1 is transferred to the printed circuit board 2 while the forward squeegee 7c moves toward the forward path A, but the backward squeegee 7d moves toward the backward path B. Needless to say, it is possible to transfer the cream solder 1 to the printed circuit board 2.

[0063]

As described above, according to the printing method of the present invention, the printing paste is moved by scratching the screen mask with a squeegee, and the printing is performed in the through holes formed in the screen mask in contact with the printing medium. Filling the paste, separating the screen mask and the printing medium by blowing gas and extruding the printing paste filled in the through-holes of the screen mask to transfer the printing paste to the printing medium, thereby forming a screen mask. In the plate release process of the printing paste filled in the through-hole, the printing paste filled in the through-hole can be effectively extruded by the gas blown from the gas outlet of the spraying means, and the printing paste filled in the through-hole of the screen mask. Can be easily separated from the plate, even under high aspect conditions.
The printing paste can be stably supplied to the printing medium, and a good printing paste can be transferred to the printing medium.

Even in the case of offset printing in which alignment and transfer are performed with a gap provided between the screen mask and the printing medium, the screen mask and the printing medium are arranged with a gap therebetween. Then, the printing paste on the screen mask is scratched with a squeegee to press the screen mask against the object to be printed, and the printing mask is filled with a printing paste in a through hole formed in the screen mask. The same effect can be obtained by moving the squeegee while blowing and extruding a gas onto the printing paste filled in the through-hole to separate the screen mask from the printing medium and transfer the printing paste to the printing medium.

Further, according to the printing apparatus of the present invention, the printing method of the present invention can be realized by providing the blowing means for blowing gas to the screen mask on the upper side in the moving direction of the squeegee. it can.

Further, a forward squeegee for scraping the print paste on the outward pass and a return squeegee for scraping the print paste on the return pass are provided, respectively on the upper side of the moving direction of the forward squeegee and the upper side of the moving direction of the return squeegee. In the case of a printing apparatus provided with spraying means, it is not necessary to reverse the squeegee and the spraying means depending on the moving direction of the squeegee, and the print paste can be transferred on both the outward path and the return path. The time can be significantly reduced.

Also, in the vicinity of the front end of the squeegee which is inclined such that the rear end of the squeegee is located on the upper side in the moving direction of the squeegee compared to the front end of the squeegee, the squeegee is blown closer to the upper side in the moving direction of the squeegee. In the case of the printing apparatus provided with the gas outlet of the attaching means, the gas can be blown from the gas outlet to the print paste of the through hole immediately after the printing paste of the screen mask is scratched with a squeegee.

In the case of a printing apparatus in which the spraying means is provided with a gas reservoir between an input port to which gas is supplied and a gas outlet so as to blow gas uniformly from the entire area of the gas outlet. Since the gas can be blown out uniformly from the entire area of the gas blowout port, it is not necessary to perform the operation of positioning the gas blowout port for each through-hole of the screen mask and spraying the gas.

Also, in the case of a printing apparatus in which the blowing means is configured so that the gas outlet thereof is in contact with the screen mask, the gas is blown only within the intended range of the screen mask and does not leak to the outside. Thus, gas can be efficiently blown to the printing paste in the through-hole, and the extrusion pressure can be effectively applied.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a printing apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a printing step of transferring cream solder according to the first embodiment;

FIG. 3 is an explanatory view showing a deformed state of the cream solder by gas blowing according to the first embodiment.

FIG. 4 is a sectional view of a main part of a spraying unit according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a spraying unit according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a main part of a printing apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a view showing a transfer volume ratio depending on an aspect ratio according to the fourth embodiment.

FIG. 8 is a characteristic diagram of an input air flow rate and a blowing pressure of a gas blowing port according to the fourth embodiment.

FIG. 9 is a schematic cross-sectional view showing a printing apparatus different from each embodiment.

FIG. 10 is a schematic configuration diagram of a main part of a conventional printing apparatus.

FIG. 11 is an enlarged cross-sectional view showing a conventional printing step of transferring cream solder.

[Explanation of symbols]

 Reference Signs List 6 spraying means 6a gas outlet 6b input port 6c gas reservoir 6e block 6f sealing member 6g elastic body 7 squeegee 7c forward squeegee 7d return squeegee 9 screen mask lifting means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiaki Yamauchi 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Term (reference) 2C035 AA06 FC10 FD00 FD02 FD19 FD27 FD35 FD37 FF26 5E319 BB05 CC33 CD29 5E343 EE25 FF04

Claims (9)

[Claims] 1. A printing mask is moved by scratching a screen mask with a squeegee, and a printing paste is filled into a through hole formed in the screen mask which is in contact with a printing medium, and a through hole of the screen mask is filled. A printing method in which the screen mask and the printing medium are separated while the gas is blown and extruded onto the printing paste to transfer the printing paste to the printing medium. 2. A screen mask and an object to be printed are placed in contact with each other, and a printing paste on the screen mask is scratched with a squeegee to fill a through hole formed in the screen mask. A printing method in which the screen paste on the upper side in the moving direction of the squeegee is pushed up while blowing a gas to the printing paste filled in the squeegee, and the screen mask is separated from the printing medium to transfer the printing paste to the printing medium. 3. A screen mask and a printing medium are arranged with a gap therebetween, and the printing mask on the screen mask is scratched with a squeegee to press the screen mask against the printing medium to make contact with the printing medium. Filling the through-hole formed in the screen mask with the printing paste, moving the squeegee while blowing and extruding gas onto the printing paste filled in the through-hole of the screen mask to separate the screen mask and the printing medium. A printing method for transferring a printing paste to a printing medium. 4. The printing paste on the screen mask is scratched with a squeegee to fill the through holes of the screen mask.
A printing apparatus for transferring a printing paste filled in the through-hole to a printing medium, wherein a blowing means for blowing gas to the screen mask is provided on the upper side in the moving direction of the squeegee. 5. A screen mask lifting means provided on the upper side of the squeegee moving direction to move the screen mask away from the printing medium in conjunction with the movement of the squeegee.
The printing device according to the above. 6. A forward pass squeegee for scraping print paste on the forward pass and a return pass squeegee for scraping print paste on the return pass,
6. The printing apparatus according to claim 4, wherein spray means are provided on each of the upstream side in the moving direction of the forward squeegee and the upstream side in the moving direction of the return squeegee. 7. A squeegee blows in the vicinity of the front end of the squeegee which is inclined such that the rear end of the squeegee is located on the upper side in the moving direction of the squeegee relative to the front end of the squeegee. The printing apparatus according to any one of claims 4 to 6, further comprising a gas outlet of the attaching means. 8. The gas spraying means according to claim 4, wherein a gas reservoir is provided between an input port to which gas is supplied and a gas outlet, and gas is blown out uniformly from the entire area of the gas outlet. Item 8. A printing device according to any one of Items 7. 9. The printing apparatus according to claim 4, wherein the spraying means is configured such that its gas outlet is brought into contact with the screen mask.