JP2003136676A - Screen printing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid defect of a mesh trace, a blur or the like by precisely and finely adjusting a printing pressure regardless of a size (weight) of a squeegee. SOLUTION: A cylinder main body 23 of an air cylinder 22 is provided on a base plate 2, and its piston rod 26 is protruded below the base plate 21. A squeegee-constituting body including the squeegee 33 is fitted to a lower end part of the piston rod 26. A tensile coil spring 36 for lightening an apparent weight by cancelling a corresponding content to a weight of the squeegee- constituting body 30 is provided between the base plate 21 and the squeegee- constituting body 30. Then, though the size of the squeegee 33 is increased and though as the air cylinder 22, that of a small diameter is used, the squeegee can be sufficiently floated, and the printing pressure can be precisely and finely adjusted with the cylinder of the small diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing device using gas pressure.

[0002]

2. Description of the Related Art A screen printing apparatus, which prints by sliding a squeegee while pressing it against a screen mask, is called an air float system. The squeegee is levitated by air pressure to a screen mask by a squeegee. There is one that allows the pressing force (printing pressure) to be adjusted.

FIG. 6 is a front view of a part of an example of such a conventional screen printing apparatus, and FIG. 7 is a vertical sectional side view taken along the line CC. In this screen printing apparatus, a base plate 1 having a rectangular plane is reciprocally moved in the horizontal direction by a base plate conveying means (not shown). A cylinder body 3 of an air cylinder 2 is vertically provided at the center of the upper surface of the base plate 1. A first port 4 is provided on the upper portion of the cylinder body 3, and a second port 5 is provided on the lower portion. The piston rod 6 of the air cylinder 2 penetrates through a fool hole 7 formed in the central portion of the base plate 1 and projects below the base plate 1.

Ring-shaped guide members 8 are provided on the left and right sides of the upper surface of the base plate 1. A guide bar 9 is vertically movably inserted through the central portion of the guide member 8. The two guide rods 9 penetrate downward holes (not shown) formed on both left and right sides of the base plate 1 and are projected below the base plate 1. At the lower end of the two guide rods 9 and the lower end of the piston rod 6 of the air cylinder 2, the squeegee structure 1 is attached.
A support block 11 having a rectangular parallelepiped shape of 0 is attached. The squeegee structure 10 has a structure in which a flat plate-shaped squeegee 13 is held on the lower surface side of the support block 11 via a mounting block 12 with a longitudinal edge thereof kept horizontal while being slightly inclined in the sliding direction. There is.

When performing printing with this screen printing apparatus, first, the material to be printed 15 is positioned and placed on the upper surface of the printing stage 14, and the screen mask 16 is arranged above it, and the screen mask 16 is placed. Ink 17 is supplied to a predetermined position on the upper surface of the. Then, the squeegee 13 is moved forward together with the base plate 1 and the like by the base plate conveying means,
The forward squeegee 13 slides while pressing the screen mask 16, so that the ink 17 is printed and applied on the upper surface of the printing target material 15 through the screen mask 16 in accordance with the mask pattern.

In this case, normally, the weight of the squeegee structure 10 is supported by the rising force of the air pressure (raising pressure) supplied to the second port 5 to bring it into a floating state, and in this state, the first portion of the air cylinder 2 is lifted. The squeegee 13 is moved to the screen mask 1 by the descending force of the air pressure (down pressure) supplied to the port 4.
Press 6 Therefore, the magnitude of the descending air pressure supplied to the first port 4 becomes the printing pressure with which the squeegee 13 presses the screen mask 16. Therefore, the substrate 1
Even if the squeegee 13 rises due to the undulations on the upper surface of No. 5, the desired printing pressure is always kept constant by controlling the air supply and withdrawal so that the above-mentioned downward pressure reduction and rising pressure do not change. Secured.

By the way, in the technical field of liquid crystal display devices, for example, two glass substrates are attached to each other via a substantially rectangular frame-shaped sealing material made of epoxy resin or the like, and a liquid crystal is placed between both glass substrates inside the sealing material. Although injected, the sealing material is often formed by screen printing. In this case, in order to improve the productivity, prepare a glass substrate as a base of the liquid crystal display device having a size corresponding to a plurality of liquid crystal display devices, and prepare a plurality of glass substrates for a predetermined process. It is manufactured in a lump and then divided into individual units. In addition, 2 in the state before dividing into each individual
The large glass substrates are bonded together via a plurality of sealing materials, but in order to ensure the retention of the gap before being divided into individual units, a gap is held in the outer peripheral portion between the two large glass substrates. The sealing material (hereinafter referred to as the outer peripheral sealing material) is formed over the entire circumference or in some places.

However, since the installation range of the outer peripheral sealing material is considerably wider than that of a normal sealing material, the squeegee 13 for forming the outer peripheral sealing material by screen printing is also considerably large, and accordingly, the support block 11 and the mounting block are attached. 12 is also considerably large, and the weight of the squeegee structure 10 is considerably large. When the weight of the squeegee structure 10 increases, the lifting force of the air cylinder 2 must be increased in order to levitate the squeegee structure 10, and as a result, the air cylinder 2 having a large diameter must be used.

On the other hand, if the diameter of the air cylinder 2 becomes large, it becomes difficult to finely adjust the printing pressure. For example, the inner diameter of the air cylinder 2 is 10φ, 16φ, 20φ, 25
Prepare φ, 32φ, 40φ, and air cylinder 2
The maximum pressure of the air supplied to 6kgf / cm2,
When the weight of the squeegee structure 10 is 0 (floated), the relationship between the air cylinder diameter and the printing pressure is as shown in FIG. In this case, the horizontal axis of FIG. 10 shows the air pressure (down pressure) supplied to the first port 4 of the air cylinder 2. As is apparent from FIG. 10, the inclination angle of the straight line showing the relationship between the air pressure and the printing pressure increases as the inner diameter of the air cylinder 2 increases. This means that it becomes more difficult to finely adjust the printing pressure as the inner diameter of the air cylinder 2 increases.

[0010]

As described above, in the above-mentioned conventional screen printing apparatus, when a large squeegee 13 is used and an air cylinder 2 having a large diameter is used, a small amount of pressure is required when setting the printing pressure. Adjustment becomes difficult. As a result, when the outer peripheral sealing material is formed on the large glass substrate using the conventional screen printing device,
If the printing pressure is too high, the screen mask 15 is pressed against the surface of the alignment film already formed in each element formation region on the large-sized glass substrate to leave a mesh mark, which may cause alignment failure on the surface of the alignment film. However, when the printing pressure is too low, there is a problem in that the outer peripheral sealing material is not formed or the printing amount is small and the image is faint. An object of the present invention is to provide a screen printing device capable of finely adjusting the printing pressure with high accuracy regardless of the size (weight) of the squeegee.

[0011]

According to a first aspect of the present invention, there is provided a screen printing apparatus in which the squeegee is printed by sliding the squeegee while pressing the squeegee on the screen mask. It has a gas pressing means for pressing the screen mask with a gas pressure, and a squeegee floating means for applying a levitation force for floating the squeegee to the squeegee independently of the gas pressing means. It is what In the screen printing apparatus of the present invention, as described in claim 2, it is preferable that the squeegee levitation means is an atmospheric levitation means that uses gas pressure as the levitation force.
Further, as described in claim 3, the squeegee levitation means may be elastic levitation means that uses elastic force of an elastic body as the levitation force. In this case, as described in claim 4,
Air pressure levitation means for levitation of the squeegee by gas pressure is provided separately from the elastic levitation means, and the levitation action by the gas pressure of the air pressure levitation device and the pressure action by the gas pressure of the gas urging means are combined. It is preferable to use an air cylinder. Further, according to the present invention, since at least a part of the levitation force acts on the squeegee independently of the pressing force serving as the printing pressure, the levitation force that acts independently even when the weight of the squeegee increases. By this, a considerable amount of the weight of the squeegee can be offset.
Therefore, even if the weight of the squeegee becomes large and the levitation means becomes large, it is not necessary to enlarge the squeegee pressing means, and the printing pressure can be finely adjusted with high precision by the small pressing means.
It is possible to reliably prevent the generation of defective mesh traces and scratches.

[0012]

1 is a front view of a main part of a screen printing apparatus according to a first embodiment of the present invention.
Shows a vertical side view along the line AA.
In this screen printing device, a base plate 21 having a rectangular plane is reciprocally moved in the horizontal direction by a base plate conveying means (not shown). A cylinder body 23 of an air cylinder 22 is vertically provided at the center of the upper surface of the base plate 21. The first on the top of the cylinder body 23
A port 24 is provided and a second port 25 is provided at the bottom. Piston rod 26 of air cylinder 22
Penetrates through a fool hole 27 formed in the central portion of the base plate 21 and projects downward from the base plate 21.

Ring-shaped guide members 28 are provided on the left and right sides of the upper surface of the base plate 21. Guide member 28
A guide rod 29 is vertically movably inserted in the central portion of the. The two guide rods 29 penetrate through stupid holes (not shown) formed on both left and right sides of the base plate 21.
Is projected below. At the lower end of the two guide rods 28 and the lower end of the piston rod 26 of the air cylinder 22, a rectangular parallelepiped support block 3 of the squeegee structure 30 is provided.
1 is attached. The squeegee structure 30 has a structure in which a squeegee 33 having a rectangular side surface is provided on a lower surface side of a support block 31 with a mounting block 32 being slightly inclined in a predetermined direction.

Pins 34 are provided at two predetermined positions on the front end surface and two predetermined positions on the rear end surface of the base plate 21.
Corresponding to these four pins 34, the support block 31
Pins 35 are provided at predetermined two positions on the front end face and at predetermined two positions on the rear end face, respectively. A tension coil spring 36 is provided between the corresponding pins 34 and 35. These tension coil springs 36 constitute elastic means for giving a rising force to the squeegee structure 30 by elastic force.

When performing printing with this screen printing apparatus, first, the material to be printed 38 is positioned and placed on the upper surface of the printing stage 37, the screen mask 39 is arranged above it, and the screen mask 39 is placed. Ink 40 is supplied to a predetermined place on the upper surface of the. Then, the squeegee 33 is moved forward together with the base plate 21 and the like by the base plate conveying means, and the forward squeegee 33 is moved to the screen mask 39.
By sliding while pressing the ink, the ink 40 is printed according to the mask pattern of the screen mask 39.
7 is applied by printing on the upper surface.

In the screen printing apparatus of the present invention, the weight of the squeegee structure 30 is balanced by the lifting force of the air cylinder 22 and the lifting force (elastic force) of the tension coil spring 36, and the squeegee 33 presses the screen mask 39. The printing pressure is generated by the downward force of the air cylinder 22. Accordingly, even if the size of the squeegee 33 becomes large and the weight of the squeegee structure 30 becomes large, the elastic force of the tension coil spring 36 cancels out a considerable amount of the weight of the squeegee structure 30, and the air cylinder 2
The lifting force by 2 can be made small, and as a result, the air cylinder 22 having a smaller diameter can be used.

As described above, in the screen printing apparatus according to the present invention, the elastic force of the tension coil spring 36 cancels out a considerable amount of the weight of the squeegee structure 30.
Regardless of the size (weight) of the squeegee 3, the air cylinder 22 having a small diameter can be used sufficiently.
0 can be floated. As a result, even if the size of the squeegee 33 becomes large and the printing area becomes large, the printing pressure can be finely adjusted with high accuracy, and it is possible to prevent defects such as mesh traces and blurring from occurring.

As an example, assuming that the maximum pressure of dry air in the factory is 6 kgf / cm2, the squeegee structure can be floated when the air cylinder 22 having an inner diameter of 10φ which can finely adjust the printing pressure is used. The weight of the body 30 is up to 4 kg. Therefore, in order to drive the 10 kg large squeegee structure 30 using the 10φ air cylinder 22, the weight of 6 kg in it may be offset by the tension coil spring 36. As described above, according to the method of the present invention using the tension coil spring 36, even if the weight of the squeegee structure 30 is 10 kg, the tension coil spring 36 cancels the weight of 6 kg, so that the apparent appearance of the squeegee structure 30 is reduced. Since the weight of the squeegee is reduced to 4 kg, even if the air cylinder 22 having an inner diameter of 10φ is used, the squeegee constructing body 30 of 10 kg can be sufficiently floated.

In the above embodiment, the case where the squeegee structure 30 is levitated by the air pressure and the elastic force of the spring has been described, but the present invention is not limited to this. For example, the second port 25 of the air cylinder 22 is used for exhaust, and the elastic force of the four tension coil springs 36 cancels out the total weight of the squeegee component 30 so that the squeegee component 30 elastically ejects the tension coil spring 36. You may make it levitate only by force.

Further, in the above-described embodiment, the tension coil spring 36 is used as an elastic body that gives a rising force to the squeegee structure 30.
However, the present invention is not limited to this, but a rubber member such as a rubber band or a plate rubber having locking holes at both ends may be used, though not shown.

Next, FIG. 3 shows a front view of a main part of a screen printing apparatus as a second embodiment of the present invention, and FIG. 4 shows a vertical side view taken along the line BB. In this screen printing apparatus, a base plate 41 having a rectangular plane is reciprocally moved in the horizontal direction by a base plate conveying means (not shown). A first air cylinder support plate 43 is provided on the lower surface side of the base plate 41 via a pair of columns 42. First air cylinder support plate 4
A cylinder body 45 of the first air cylinder 44 is vertically provided in the central portion of the upper surface of 3. Cylinder body 4
5 is provided with a first port 46 on the upper part and a second port 46 on the lower part.
A port 47 is provided. First air cylinder 4
The piston rod 48 of No. 4 penetrates the stupling hole 49 formed in the central portion of the first air cylinder support plate 43, and
Of the air cylinder supporting plate 43.

The lower end of the piston rod 48 of the first air cylinder 44 is fixed to the center of the upper surface of the support plate 51 of the squeegee structure 50. The squeegee structure 50 is
A rectangular parallelepiped support block 53 is provided on the lower surface side of the support plate 51 via a pair of columns 52, and a flat plate-shaped squeegee 5 is provided on the lower surface side of the support block 53 via an attachment block 54.
5 has a structure in which the longitudinal edges thereof are horizontally held while being slightly inclined in the sliding direction. Support plate 5
Ring-shaped guide members 56 are provided on both the left and right sides of 1. A guide rod 57 is vertically movably inserted through the central portion of the guide member 56. The upper ends of the two guide bars 57 are attached to the left and right sides of the lower surface of the first air cylinder support plate 43.

The left and right sides of the upper surface of the second air cylinder support plate 58 are attached to the lower ends of the two guide rods 57. At the center of the lower surface of the second air cylinder support plate 58, the second air cylinder 44 having a second diameter larger than that of the first air cylinder 44 is provided.
The cylinder body 60 of the air cylinder 59 is vertically provided. At the bottom of the cylinder body 60, the first port 6
1 is provided, and a second port 62 is provided on the upper part. Piston rod 63 of the second air cylinder 59
Is projected through the fool hole 64 formed in the central portion of the second air cylinder support plate 58 to the upper side of the second air cylinder support plate 58, and the upper end thereof is squeegee structure 5.
It is attached to the central portion of the lower surface of the support plate 51 of No. 0.

When performing printing with this screen printing apparatus, first, the material 66 to be printed is positioned and placed on the upper surface of the printing stage 65, the screen mask 67 is arranged above it, and the screen mask 67 is placed. Ink 68 is supplied to a predetermined place on the upper surface of the. Then, the squeegee 55 is moved forward together with the base plate 41 and the like by the base plate conveying means, and the forward squeegee 55 is moved to the screen mask 67.
By sliding while pressing the ink 68, the ink 68 is printed according to the mask pattern of the screen mask 67.
6 is applied by printing on the upper surface.

In this case, the second ports 47 and 62 of the first and second air cylinders 44 and 59 are for exhaust. Then, the squeegee structure 5 is driven by the air pressure (down pressure) supplied to the first port 46 of the first air cylinder 44.
Apply a descending force to 0. In addition, the second air cylinder 59
The air pressure (increase pressure) supplied to the first port 61 applies an increasing force to the squeegee structure 50.

By the way, since the second air cylinder 59 has a larger diameter than the first air cylinder 44, the ascending force of the second air cylinder 59 should be made larger than the descending force of the first air cylinder 44. You can The weight of the squeegee structure 50 is balanced by the lifting force of the second air cylinder 59,
The printing pressure by which 5 presses the screen mask 67 is provided by the descending force of the first air cylinder 44. Therefore, the size of the squeegee 55 becomes large and the weight of the squeegee component 50 becomes large, and the diameter of the second air cylinder 59 becomes large in order to obtain a large lifting force (lifting force) to offset this weight. However, since the printing pressure is generated by the first air cylinder 44 having a small diameter, a large squeegee 5
Even when 5, the printing pressure can be adjusted with high accuracy.

As described above, in the screen printing apparatus of the present invention, since the second air cylinder 59 for floating the squeegee 55 is provided separately from the first air cylinder 44 that causes the printing pressure, the size of the squeegee 55 is large. Regardless of the size (weight), even if the first air cylinder 44 having a small diameter is used, the squeegee structure 50 can be sufficiently floated. As a result, even if the size of the squeegee 55 becomes large and the printing area becomes large, it is possible to finely adjust the printing pressure with high accuracy, and it is possible to prevent defective mesh traces, blurring, and the like from occurring.

In the second embodiment, the case where the second air cylinder 59 having a diameter larger than that of the first air cylinder 44 is used has been described, but the present invention is not limited to this. For example, the third embodiment of the present invention shown in FIG. 5 may be used. That is, two second air cylinders 59a, 59a having the same diameter as the first air cylinder 44 are provided on the lower surface of the second air cylinder support plate 58.
b cylinder bodies 60a, 60b are provided vertically, and the upper ends of their piston rods 63a, 63b are attached to the lower surface side of the support plate 51 of the squeegee constructing body 50 by the rising force of the two second air cylinders 59a, 59b. It is also possible to offset the total weight of the squeegee structure 50 and adjust the printing pressure by the descending force of the first air cylinder 44.

By the way, in the first embodiment shown in FIG.
The lower end of the piston rod 26 of the air cylinder 22 is attached to the upper surface side of the support block 31. However, in this case, since the support block 31 is indirectly attached to the base plate 21 via the tension coil spring 36, the lower end portion of the piston rod 26 of the air cylinder 22 is simply brought into pressure contact with the upper surface of the support block 31. You may do it.

Further, in the second embodiment shown in FIG. 4, the first
The lower end portion of the piston rod 48 of the air cylinder 44 is attached to the upper surface side of the support plate 51, and the upper end portion of the piston rod 63 of the second air cylinder 59 is attached to the lower surface side of the support plate 51. However, in this case, since the support plate 51 is supported by the two guide rods 57 so as to be vertically movable and is sandwiched by the tip portions of both piston rods 48 and 63, the tip portions of both piston rods 48 and 63 are fixed. Support plate 5
Alternatively, the upper surface and the lower surface of 1 may be simply brought into pressure contact with each other. This also applies to the third embodiment shown in FIG.

[0031]

As described above, according to the present invention, since at least a part of the levitation force acts on the squeegee independently of the pressing force serving as the printing pressure, the weight of the squeegee increases. Also, the levitation force acting independently can cancel a considerable amount of the weight of the squeegee. Therefore, even if the weight of the squeegee becomes large and the levitation means becomes large, it is not necessary to enlarge the squeegee pressing means, and the printing pressure can be finely adjusted with high precision by the small pressing means.
It is possible to reliably prevent the generation of defective mesh traces and scratches.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a screen printing apparatus according to a first embodiment of the present invention.

2 is a vertical cross-sectional side view taken along the line AA of FIG.

FIG. 3 is a front view of a main part of a screen printing apparatus according to a second embodiment of the present invention.

4 is a vertical cross-sectional side view taken along the line BB in FIG.

FIG. 5 is a vertical sectional side view similar to FIG. 4, showing a screen printing apparatus as a third embodiment of the invention.

FIG. 6 is a partial front view of an example of a conventional screen printing apparatus.

7 is a vertical cross-sectional side view taken along the line CC of FIG.

FIG. 8 is a diagram shown for explaining a relationship between an air cylinder diameter and printing pressure.

[Explanation of symbols] 21 base plate 22 Air cylinder 26 Piston rod 30 Squeegee structure 33 Squeegee 39 screen mask

Claims (4)

[Claims] 1. A screen printing apparatus for printing by sliding a squeegee against a screen mask while pressing the squeegee, and a gas pressing means for pressing the squeegee against the screen mask by a gas pressure, and for floating the squeegee. And a squeegee levitation unit that exerts the levitation force of the squeegee on the squeegee independently of the gas pressing unit. 2. The screen printing apparatus according to claim 1, wherein the squeegee levitation means is atmospheric levitation means that uses gas pressure as the levitation force. 3. The screen printing apparatus according to claim 1, wherein the squeegee levitation means is elastic levitation means that uses elastic force of an elastic body as the levitation force. 4. The invention according to claim 3, wherein a pneumatic levitation means for levitation of the squeegee by gas pressure is provided separately from the elastic levitation means, and the levitation action by the gas pressure of the atmospheric levitation means and the gas pressing force. The screen printing device characterized in that the pressing action by the gas pressure of the means is performed by one air cylinder.