The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2015-145844, filed Jul. 23, 2015, entitled “Printing Apparatus.” The contents of this application are incorporated herein by reference in their entirety.
1. Field
The present disclosure relates to a printing apparatus.
2. Description of the Related Art
In general, using a screen a screen printing is adopted to perform printing on a workpiece by applying an application material, such as an ink or a paste, thereon. For example, Japanese Unexamined Patent Application Publication No. 2011-20395 discloses a printing apparatus including a screen, a scraper, and a squeegee. The screen is disposed above a print stage. The scraper is disposed above the screen and coats the screen with a transfer material by moving on the screen. The squeegee transfers the transfer material to a substrate, which is placed below the screen, by moving on the screen.
The scraper includes a blade and an auxiliary blade. The blade extends downward to the print stage and coats the screen with the transfer material by using a lower end portion thereof. The auxiliary blade is connected to the blade. The auxiliary blade extends substantially continuously from a position on the blade by a predetermined length in a moving direction in which the scraper moves to coat the screen. The position is separated from an end surface, facing the print stage, of the lower end portion of the blade.
It is described that, with such a structure, the scraper can uniformly coat the screen with the transfer material, and stability of transfer can be increased.
Moreover, a water-repellent layer is disposed on a surface of the auxiliary blade facing the screen (hereinafter, also referred to as an “inner surface”). Therefore, a sealing material adhering to the auxiliary blade can be easily peeled off the auxiliary blade and can be dropped to a position that is located near the lower end portion of the blade, below the auxiliary blade, and in the moving direction of the blade.
According to one aspect of the present invention, a printing apparatus includes a screen, a scraper, and a squeegee. The screen is placed on a workpiece. The scraper coats the screen with a paste by moving on the screen. The squeegee transfers the paste, with which the screen has been coated by the scraper, to the workpiece by moving on the screen. The scraper includes a vertical portion and a curved portion. The vertical portion extends toward the screen in a vertical direction. The curved portion is curved from a lower end of the vertical portion in a direction opposite to a moving direction in which the scraper moves to coat the screen with the paste. The curved portion has an opening that extends in a horizontal width direction that crosses the moving direction.
According to another aspect of the present invention, a printing apparatus includes a screen, a scraper, and a squeegee. The screen has a screen surface which has a width direction and which is to be placed on a workpiece. The scraper is to be movable along the screen surface in a first direction perpendicular to the width direction so as to coat the screen surface with a paste. The scraper includes an upper portion and a curved portion. The upper portion extends from an upper end to a lower end of the upper portion toward the screen surface in a direction perpendicular to the screen surface. The curved portion is connected to the lower end of the upper portion and extending in the width direction. The curved portion has a curved shape projecting toward a second direction opposite to the first direction viewed in the width direction. The curved portion has an opening extending in the width direction. The squeegee is to be movable along the screen surface so as to transfer to the workpiece the paste with which the screen has been coated by the scraper.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.
The embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.
Referring to
A paste P is placed on the screen 14. The paste P is a material having a high viscosity, which is made, for example, by dissolving a silicone resin, a fluorocarbon resin, a platinum catalyst, carbon, or the like in a solvent. The viscosity of the paste P is in the range of 30 to 200 Pa·s.
A scraper 18 and a squeegee 20, which are respectively movable in the direction of arrow A and in the direction of arrow B while being in contact with the screen 14, are disposed above the screen 14. The scraper 18 and the squeegee 20 are moved by a driving mechanism 21 in the direction of arrow A, in the direction of arrow B, and in the direction of arrow C. The scraper 18 and the squeegee 20 may move in the direction of arrow A and in the direction of arrow B together or independently.
Referring to
Referring to
The opening 26 is defined by a lower wall surface 26d and an upper wall surface 26u, which are long and extend in the horizontal width direction, and a right wall surface 26r and a left wall surface 261, which are short and extend in the vertical direction. The lower wall surface 26d, which is adjacent to the screen 14, includes a concave/convex portion 28. The concave/convex portion 28 includes convex portions 28p, which are curved so as to protrude upward, and concave portions 28r, which are curved so as to be indented downward. Instead of the convex portions 28p and the concave portions 28r, the lower wall surface 26d may have a zigzag shape.
Referring to
Referring to
Referring to
An operation of the printing apparatus 10, which is constructed as described above, will be described below.
First, referring to
Referring to
In the present embodiment, the curved portion 22b of the scraper 18 has the opening 26, which extends in the horizontal width direction. Accordingly, the paste P moves from a lower position toward an upper position along the inner surface 22bin of the curved portion 22b, and, due to the presence of the opening 26, a frictional force is considerably reduced or the frictional force is reduced. Thus, the paste P is removed from the inner surface 22bin of the curved portion 22b and drops from the inner surface 22bin due to its own weight, is agitated as the paste P repeatedly rolls, and the screen 14 is uniformly coated with the paste.
Moreover, in the present embodiment, referring to
Therefore, on the inner surface 22bin of the curved portion 22b, the vertex positions of the convex portions 28p and the vertex positions of the concave portions 28r are located at different heights. Accordingly, the paste P is removed from the inner surface 22bin of the curved portion 22b at different timings, so that an advantage is obtained in that the rotation speed of the paste P varies and the performance of agitating the paste P is effectively improved.
Furthermore, referring to
Therefore, the present embodiment has an advantage in that, even if the paste P has a high viscosity, the paste P does not stick to the scraper 18 and a printed product having a desired quality can be obtained easily and reliably.
Referring to
Referring to
A printing apparatus according to the present disclosure includes a screen placed on a workpiece, a scraper, and a squeegee. The scraper coats the screen with a paste by moving on the screen. The squeegee transfers the paste, with which the screen has been coated by the scraper, to the workpiece by moving on the screen.
The scraper includes a vertical portion that extends toward the screen in a vertical direction, and a curved portion that is curved from a lower end of the vertical portion in a direction opposite to a moving direction in which the scraper moves to coat the screen with the paste. The curved portion has an opening that extends in a horizontal width direction that crosses the moving direction.
In the printing apparatus, preferably, a lower wall surface, which is one of wall surfaces defining the opening and extending in the horizontal width direction and which is adjacent to the screen, includes a concave/convex portion.
In the printing apparatus, preferably, an inner surface of the curved portion that comes into contact with the paste is water-repellent treated.
With the present disclosure, the curved portion of the scraper has the opening, which extends in the horizontal width direction. Therefore, when the scraper moves on the screen and coats the screen with the paste, the paste moves from a lower position toward an upper position along the curved portion, and, due to the presence of the opening, a frictional force is considerably reduced or the frictional force is reduced.
Accordingly, the paste drops from the inner surface of the curved portion due to its own weight, is agitated as the paste repeatedly rolls, and the screen is uniformly coated with the paste. Thus, even if the paste has a high viscosity, the paste does not stick to the scraper and a printed product having a desired quality can be obtained easily and reliably.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
Number | Date | Country | Kind |
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2015-145844 | Jul 2015 | JP | national |
Number | Name | Date | Kind |
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5027703 | Hancy | Jul 1991 | A |
5685221 | Newman | Nov 1997 | A |
20130269553 | Nishimoto | Oct 2013 | A1 |
Number | Date | Country |
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2011-020395 | Feb 2011 | JP |
2013161871 | Aug 2013 | JP |
2013184402 | Sep 2013 | JP |
Number | Date | Country | |
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20170021610 A1 | Jan 2017 | US |