JP2002011846A - Printing squeegee and screen printing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing squeegee of a long life which effectively prevents printing paste from sticking thereto and can transfer the printing paste in a prescribed thickness on a matter to be printed and which dispenses with frequent cleaning, and a screen printing method using the same. SOLUTION: The printing squeegee is constituted of a plate-shaped body 6 made of a metal or a rubber and it pushes out the printing paste on a screen plate from an opening of the screen plate, at one end side thereof, to print the printing paste on the matter to be printed. A titanium oxide film 7 is adhered at least to a portion coming into contact with the printing paste, in the surface of the plate-shaped body 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing squeegee used for screen-printing a printing paste on an object to be printed, and a screen printing method using the squeegee.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a circuit board or an electronic component, a printing paste for forming a resistance layer, a conductor layer, or the like is applied to a substrate (coating) through a screen plate (mask) having a predetermined pattern. Screen printing technology for printing on printed matter) is widely used.

In such a screen printing technique, for example, as shown in FIG. 4, a predetermined amount of a printing paste 13 is placed on a screen plate 12 positioned and placed on a printing substrate 11, and then printed. 13 is extruded from the opening 15 of the screen plate 12 with a printing squeegee 14,
Printing is performed by transferring this to the upper surface of the printing substrate 11.

The printing squeegee 14 is made of urethane rubber or stainless steel and has a thickness of 1 mm to 15 m.
An approximately m plate-like body is used.

[0005]

By the way, the printing squeegee 14 used for the screen printing described above extrudes the printing paste 13 from the opening 15 of the screen plate 12 while stirring the printing paste 13.
The printing paste 13 is easily adhered to the surface of the printing squeegee 14 made of urethane rubber, stainless steel, or the like. Therefore, the screen version 12
A part of the printing paste 13 to be filled in a state where the inside of the opening (pattern hole) 15 is sufficiently filled may be dragged by the printing squeegee 14 to cause a problem that the surface thereof is concavely concave. In this case, the thickness of the printing paste 13 transferred to the printing substrate 11 is thinner in the central part than in the outer peripheral part, so that a conductor layer or a resistance layer of a circuit board or an electronic component is formed. However, there is a disadvantage that the required characteristics required for the above-mentioned method cannot be obtained.

As described above, a large amount of printing paste 3
Is attached to the printing squeegee 4, the amount of the printing paste 13 used for screen printing is increased, and the printing squeegee 14 needs to be frequently cleaned, and the maintenance is troublesome. It also had disadvantages.

In order to solve the above-mentioned disadvantage, it has been proposed to form a water-repellent coating film made of silicon, fluorine or the like on the surface of a printing squeegee (see Japanese Patent Application Laid-Open No. 7-9663).

However, the conductive printing paste 13 used for forming a pattern on a circuit board or an electronic component is generally lipophilic in many cases. When such lipophilic printing paste 13 is used, the printing squeegee 14 is used. Even if a water-repellent coating film is formed on the surface of the above, the adhesion characteristics of the printing paste 13 to the printing squeegee 14 have not been improved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has as its object to transfer a printing paste to a printing medium to a predetermined thickness by effectively preventing the printing paste from adhering to a printing squeegee. It is an object of the present invention to provide a long-life printing squeegee that can perform the cleaning without requiring frequent cleaning and a screen printing method using the same.

[0010]

A printing squeegee according to the present invention is made of a metal or rubber plate, and is printed by extruding a printing paste on a screen plate from one end of the screen plate through an opening of the screen plate. A printing squeegee for printing a paste on a printing material, wherein a titanium oxide film is applied to at least a portion of the surface of the plate-shaped body that contacts the printing paste.

The printing squeegee of the present invention is characterized in that the thickness of the titanium oxide film is 0.1 μm to 5.0 μm.

The screen printing method of the present invention is characterized in that the printing squeegee prints on a screen plate by irradiating the titanium oxide film adhered to the surface of the printing squeegee with ultraviolet rays having a wavelength of 300 nm to 400 nm. The printing paste is printed on an object to be printed by extruding the paste from an opening of the screen plate.

According to the present invention, a titanium oxide film having a photocatalytic function is applied to a portion of the surface of the plate-like body forming the printing squeegee, which is in contact with the printing paste. By irradiating ultraviolet rays of a wavelength, super-hydrophilicity and lipophilicity are generated, and OH groups of alcohols and oil components contained in the printing paste to be attached to the surface of the printing squeegee are formed by the titanium oxide film. It will be kept well. Thereby, the friction between the printing paste and the printing squeegee is greatly reduced, and the adhesion of the printing paste to the printing squeegee is reduced,
The thickness of the printing paste transferred onto the printing substrate can be made substantially constant.

In this case, when the titanium oxide film is irradiated with ultraviolet rays of a predetermined wavelength, the dirt adhering to the surface is satisfactorily decomposed, so that it is not necessary to frequently clean the printing squeegee. The labor required for maintenance can also be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view of a printing squeegee according to one embodiment of the present invention, and FIG. 2 is a sectional view for explaining a screen printing method using the printing squeegee of FIG. A printing squeegee, 6 is a plate, and 7 is a titanium oxide film.

The printing squeegee 4 of the present embodiment has a structure in which a titanium oxide film 7 is applied to the surface of a rectangular plate 6.

The plate-shaped member 6 is made of rubber such as urethane rubber or silicon rubber or metal such as stainless steel for 1 mm.
The printing squeegee 4 has a titanium oxide film 7 at least at a portion where the printing squeegee 4 contacts the screen when the printing squeegee 4 is used for screen printing.

The titanium oxide film 7 deposited on the surface of the plate 6 is made of TiO ₂ (titanium dioxide) having a rutile-type or anatase-type crystal structure, for example, with a thickness of 0.1 μm to 5.0 μm. The titanium oxide film 7 covers a part of the surface of the plate 6.

The titanium oxide film 7 is formed on the surface of the plate-like body 6 by employing a thin film method such as a sputtering method or a vacuum evaporation method, or a thick film method such as a spray method or a dipping method.

For example, when the titanium oxide film 7 is formed by a thick film method, a predetermined paste containing TiO ₂ fine powder is applied to the surface of the plate-like body 6 by a spraying method or a dipping method, and this is heated at a high temperature. It is fixed and formed on the surface of the plate-like body 6 by heating and sintering. At this time, the sintering temperature of the titanium oxide film 7 is set, for example, to 100 ° C. to 150 ° C., and sintering is completed in about 2 to 3 minutes.

When screen printing is performed using the printing squeegee 4 described above, the wavelength of 300 nm to 40 nm is applied to the titanium oxide film 7 deposited on the surface of the printing squeegee 4.
The printing paste 3 on the screen plate 2 is extruded from the opening 5 of the screen plate 2 by the printing squeegee 4 while irradiating ultraviolet rays of 0 nm, thereby transferring and printing the printing paste 3 on the printing substrate 1.

At this time, the super-hydrophilicity and the lipophilicity are generated in the titanium oxide film 7 with the irradiation of the ultraviolet rays.

This principle will be described in detail with reference to FIG. Although TiO ₂ has chemically adsorbed water on its surface, it is unstable, so that it absorbs hydrophobic molecules in the air and is stabilized (see FIG. 3A).

When ultraviolet rays are irradiated here, as shown in FIG. 3B, the hydrophobic component undergoes photocatalytic decomposition to expose chemically adsorbed water.

Next, as shown in FIG. 3C, the physically adsorbed water is combined with the exposed chemically adsorbed water, and
As shown in (2), the physically adsorbed water is taken into the water storage material on the surface of TiO ₂ by surface diffusion and is stabilized.

As described above, when the printing paste 3 contacts the physically adsorbed water in the water storage substance on the surface of TiO ₂ , the OH group of the alcohol contained in the printing paste 3 or the oil is contained. The component is Ti
They are positively held on the surface of O ₂ , and these greatly reduce the friction with the printing paste 3. Therefore, when performing screen printing, the adhesiveness of the printing paste 3 to the printing squeegee 4 is significantly reduced, and the printing paste 3 is easily separated from the surface of the printing squeegee 4, and is filled in the opening 5 of the screen plate 2. The surface of the printed printing paste 3 is flat. This allows
The thickness of the printing paste 3 transferred and printed on the printing substrate 1 is substantially constant, and high-quality printing can be performed.

The titanium oxide film 11 serving as a photocatalyst
Has a function of generating active oxygen species by irradiation of ultraviolet rays, and therefore, the organic compound attached to the printing squeegee 4
It can be decomposed into CO ₂ and H ₂ O by strong oxidizing action. Normally, even if the printing paste 3 adhered to the printing squeegee 4 is wiped off with a wiping rag (wiper) or the like, the printing paste 3 penetrates into the back of fine lines or scratches and cannot be completely wiped off. The dirt can be removed without any trouble, and it is not necessary to frequently clean the printing squeegee 4, and the product life can be extended.

On the other hand, as a light source used for photoexcitation of the titanium oxide film 7, indoor lighting such as a fluorescent lamp, an incandescent lamp, a metal halide lamp, and a mercury lamp, sunlight, and light from those light sources are guided by a low-loss fiber. Light sources and the like can be used. The illuminance of the excitation light is 0.001 mW /
cm ² or more, but in order to more effectively exert the effect of the photocatalyst, the illuminance of the photoexcitation light should be 0.1 mW / cm ^2.
It is preferable to set the above.

In order to more effectively exert the above-mentioned photoexcitation effect, it is preferable that the crystal structure of TiO ₂ forming the titanium oxide film 7 be anatase type.

The present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

For example, in the above-described embodiment, the titanium oxide film 7 is partially deposited on the surface of the plate 6, but instead, the titanium oxide film 7 is deposited on the entire surface of the plate 6. You may do it.

In the above-described embodiment, silver, copper, palladium, platinum, rhodium,
One or more metal powders selected from the group consisting of platinum, ruthenium, gold, zinc, cobalt, iron, nickel, sodium, potassium, lithium, strontium, calcium, magnesium and compounds of these metals may be added.

Further, in the above embodiment, the titanium oxide film 7
In order to increase the water storage capacity, the titanium oxide film 7 may contain a silicone or the like in which at least a part of the organic groups bonded to silica and / or silicon atoms is substituted with hydroxyl groups.

[0035]

According to the present invention, a titanium oxide film having a photocatalytic function is applied to a portion of a surface of a plate-like body forming a printing squeegee which is in contact with a printing paste.
By irradiating the titanium oxide film with ultraviolet light of a predetermined wavelength, super-hydrophilicity and lipophilicity are generated, and OH groups of alcohol contained in a printing paste to be attached to the surface of a printing squeegee, and a fat component. Is well retained by the titanium oxide film. As a result, the friction between the printing paste and the printing squeegee is greatly reduced, the adhesion of the printing paste to the printing squeegee is reduced, and the thickness of the printing paste transferred onto the printing substrate is made substantially constant. Can be.

According to the present invention, when the titanium oxide film is irradiated with ultraviolet rays having a predetermined wavelength, the dirt adhering to the surface of the titanium oxide film is satisfactorily decomposed. Therefore, it is necessary to frequently clean the printing squeegee. Is eliminated, and the labor required for the maintenance can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a printing squeegee according to one embodiment of the present invention.

FIG. 2 is a sectional view for explaining a screen printing method using the printing squeegee of FIG. 1;

FIGS. 3A to 3D are schematic diagrams for explaining a process until superhydrophilicity is imparted to a titanium oxide film 7. FIG.

FIG. 4 is a cross-sectional view for explaining a conventional screen printing method using a printing squeegee.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Printed matter (substrate), 2 ... Screen plate, 3
... printing paste, 4 ... printing squeegee, 5 ...
Opening (pattern hole), 6: plate, 7: titanium oxide film

Claims (3)

[Claims] 1. A metal or rubber plate-like body,
A printing squeegee for printing a printing paste on a printing material by extruding a printing paste on a screen printing plate from an opening of the screen printing plate at one end side, wherein at least the printing paste of the surface of the plate-shaped body comes into contact with the printing squeegee. A printing squeegee, wherein a titanium oxide film is applied to a portion. 2. The method according to claim 1, wherein said titanium oxide film has a thickness of 0.1 μm or less.
The printing squeegee according to claim 1, wherein the thickness is 5.0 μm. 3. The printing squeegee according to claim 1 or 2, wherein the titanium oxide film adhered to the surface of the printing squeegee is irradiated with ultraviolet light having a wavelength of 300 nm to 400 nm on the screen plate with the printing squeegee. A screen printing method characterized in that the printing paste is printed on an object to be printed by extruding the printing paste from an opening of a screen plate.