JPH0482739A - Screen printing apparatus - Google Patents

Abstract

PURPOSE:To obtain not only the optimum rolling of ink but also sharp and uniform ink thickness by rotating the roller arranged at the position burried in the ink accumulated in front of a squeezee in the sliding direction thereof. CONSTITUTION:When a squeezee 2 slides along the upper surface of a screen plate 7 in an A-direction, a roller 4 is burried in the ink 10 accumulated in front of the squeezee 2 to be rotated in a B-direction at appropriate rotational speed and the rolling of the ink 10 rotated around the center of the roller 4 in a B-direction can be generated. The rotational speed of the roller 4 imparts effect on the rotational speed of the ink around the roller 4 and further exerts effect on the rolling motion of the whole of the rolling ink 10. When the ink has thixotropic properties, the viscosity of the ink is lowered by rolling and the ink becomes easy to fall in an opening part and, therefore, the thickness of the ink in the sliding direction of the squeezee of the ink after printing can be uniformized while the rotational speed of the roller 4 is appropriately controlled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention applies ink on the top surface of the screen plate to the printing surface through the openings of the screen plate using a squeegee that slides along the top surface of the screen plate. The present invention relates to a screen printing device that performs printing.

[Prior Art] In a conventional screen printing apparatus, as shown in FIG.
Ink 60 is supplied to the upper surface of the screen plate 57, and the squeegee 52 attached to the squeegee holder 51 is applied to the screen plate 57 with a predetermined printing pressure. The ink 60 is applied to the printing surface 58a through the opening of the screen plate 57 by sliding it along the upper surface of the screen plate 57 in the direction of the arrow C while pressing the screen plate 57, thereby forming a desired image.

[Problems to be Solved by the Invention] When focusing on one opening of the screen plate in the conventional screen printing apparatus described above, it is found that the closer to the end of the opening that the squeegee reaches first, the more difficult it is to fill with ink, as shown in FIG. As shown, the thickness of the ink 60a applied to the printing surface through the opening gradually increases in the direction in which the squeegee slides (direction of arrow C) and is not uniform. Depending on the shape of the opening in the plate or the angle of the opening with respect to the direction in which the squeegee slides, the desired image may become blurred.

One known method for solving these problems is to roll the ink with a sliding squeegee, and use the rolling motion to actively cause the ink to fall into the openings of the screen plate. However, the occurrence of ink rolling by the squeegee depends on various conditions such as the sliding speed of the squeegee, the viscosity of the ink, temperature, and humidity. There is a problem in that it is difficult to obtain the optimal one that satisfies the groove.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and it actively generates rolling of ink and appropriately influences the rolling movement so that the ink fills the openings of the screen plate. An object of the present invention is to provide a screen printing device capable of printing a clear image having a more uniform ink thickness on a printing surface by obtaining optimal ink rolling.

[Means for Solving the Problems] A screen printing apparatus of the present invention for achieving the above object includes: a screen plate; and the screen plate, which applies ink on the upper surface of the screen plate to a printing surface through openings of the screen plate. In a screen printing device equipped with a squeegee that slides along an upper surface, a roller whose rotational speed is controllable for rolling the ink is buried in ink that accumulates in front of the squeegee in a sliding direction. It is characterized in that it is disposed at a position parallel to the skin.

Further, the roller may have irregularities formed on its circumferential surface, or may be made of a hard material having solvent resistance.

[Operation] In the screen printing apparatus of the present invention configured as described above, the roller rotates while being buried in the ink that collects in front of the squeegee that slides along the top surface of the screen plate. Generates rolling of ink around the rotation center.

The rotational speed of the roller affects the rotational speed of rolling ink around the roller, and further affects the rolling movement of the entire rolling ink, so the rotational speed of the roller should be controlled appropriately. According to
Optimal ink rolling is obtained so that the ink falls into the openings of the screen plate and sufficiently fills the openings.

[Example] An embodiment of the present invention will be described based on the drawings.

In FIG. 1, the screen plate 7, which has openings with the same shape as the desired image shape, is separated upward by a predetermined gap amount from the printing surface 8a of the printing material 8 placed on the table 9. stretched in position.

The squeegee 2 made of rubber or the like is a plate-like object that extends in a direction perpendicular to its sliding direction (six arrow directions) (see FIG. 2), and has a wedge-shaped tip.

The squeegee holder 1 that holds the squeegee 2 is attached to a known moving mechanism (not shown), and presses the tip of the squeegee 2 against the upper surface of the screen plate 7 with a predetermined printing pressure to move the lower surface of the screen plate 7 to be printed. It is configured to slide along the upper surface of the screen plate 7 at a predetermined sliding speed in the six directions of arrows while making contact with the surface 8a.

Next, the roller 4 disposed at a position buried in the ink 10 accumulated in front of the squeegee 2 in the sliding direction will be described with reference to FIG. 2 as well.

The roller 4 is made of a hard material, such as aluminum, which is resistant to gaseous agents, and has a circular cross section (see FIG. 3) and extends longer than the length of the squeegee 2. Further, both ends of the roller 4 are rotatably supported on the free end sides (lower end end side in the figure) of two U-shaped support fittings 6a and 6b fixed to both ends of the squeegee holder l, respectively. The axis of rotation thereof is parallel to one side of the tip of the squeegee 2.

On the other hand, a known electric motor 3 whose rotational speed can be controlled is attached to the left end of the squeegee holder 1 in the figure, and a pulley 3a fixed to the output shaft of the electric motor 3 and the roller 4 A belt 5 is wound around a pulley portion 4a formed at an end projecting outward from the squeegee 2 on the left side in the figure. When the electric motor 3 is driven, the roller 4 rotates in the direction of arrow B, and by controlling the rotation speed of the electric motor 3, the rotation speed of the roller 4 can also be controlled.

Next, the operation of this embodiment will be explained.

When the squeegee 2 slides along the upper surface of the screen plate 7 in the six directions of the arrows, the roller 4 is buried in the ink 10 accumulated in front of the squeegee 2 and rotates in the direction of the arrow B at an appropriate rotational speed. When this roller 4 rotates, the ink 1 rotates in the direction of arrow B with the roller 4 as the center of rotation.
A rolling zero can be generated.

The rotational speed of the roller 4 influences the rotational speed of rolling ink around the roller 4, and further influences the rolling motion of the entire rolling ink 10. Further, when the ink has chicken tropism, the viscosity decreases due to the rolling, and it tends to fall into the opening. ), the thickness in the sliding direction of the squeegee can be made uniform.

The thickness of the ink of the image printed by the screen printing apparatus of this example was measured, and the results will be explained.

As shown in FIG. 9, the measurement was carried out by measuring the thickness of the ink 10a dropped into one opening of the screen plate 7 and applied to the printing surface 8a by sliding the squeegee 2 in the direction of arrow A. The conditions at the time of printing are as follows: The thickness T1 of the ink on the leading edge side of the opening where it is first dropped and the thickness T2 of the ink on the trailing edge side of the opening that is dropped last. It was as follows.

Temperature/humidity 125℃/65% ink
: Cream solder (RX362 manufactured by Nippon Handa Co., Ltd.)
-CR5F) Sliding speed of squeegee 2: 20 mm/sec Thickness of screen plate 7 = 150 μm Printing pressure: 0.30 kgf Outer diameter of roller 4: φ6 mm Cross-sectional shape of roller 4: Circle (see Figure 3), Surface roughness is 5S Material of roller 4 Table 1 shows the measurement results of the ink thicknesses T + and T 2 at the two cylinder locations with respect to the rotational speed of the aluminum roller 4.

Table 1 As can be seen from the measurement results shown in Table 1, in this example, under each of the above conditions, the rotational speed of the roller 4 was 30 rpm.
m to 70 rpm, the difference between the ink thicknesses T + and T 2 at the two locations was small, and an image having a more uniform ink thickness could be printed.

Next, by changing only the roller 4 of this embodiment to a roller 14 having a star-shaped cross-sectional shape with unevenness formed on the circumferential surface as shown in FIG. The thickness of the ink was measured and the results will be explained below.

The locations at which the ink thickness was measured and the conditions during printing were the same as when using the roller 4 described above. Thickness T1 of the ink at the two locations relative to the rotational speed of the roller 14. The measurement results for T2 are shown in Table 2.

Table 2 As can be seen from the measurement results shown in Table 2, even when the roller 14 with an uneven surface is used instead of the roller 4, the rotational speed of the roller 14 is 30 rpm to 60 rpm.
m range, the ink thicknesses at the two locations T3, T2
The difference in ink was reduced, and it was possible to print an image with a more uniform ink thickness.

In addition to rollers with unevenness formed on their circumferential surfaces, there are rollers 24 (Fig. 5) and rollers 34 (Fig. 6) with gear-shaped cross sections, and rollers 44 (Fig. 7) with disk-shaped sawtooth cross-sections (Fig. 7). The same image as above was printed by using the roller 54 (Fig. 8, direction of rotation is the direction of arrow B) in place of the roller 4, and the thickness of the ink was measured. The measurement results of the ink thickness TT2 at the two locations with respect to the rotational speed of each roller 24, 34, 44, 54 are the same, and it has been possible to print an image having a more uniform ink thickness.

Regarding the uneven shape of the peripheral surface of the roller, each of the rollers 14 described above
．． In addition to the shapes shown in 24.34.44.54, it may also have a wave shape, a cross-sectional shape, or a flower shape.

Regarding the material of the rollers, please refer to each roller 4.14.24 above.
．． As shown in 34.44.54, metal is highly durable, or it is not limited to metal, as long as it has solvent resistance and is made of hard material, such as plastic. It can be anything. Further, the roller may be made of mold, or a plurality of rollers may be connected to form one roller.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

By rotating a roller disposed at a position buried in the ink that accumulates in front of the squeegee in the sliding direction, it is possible to actively cause rolling of the ink, and moreover,
By appropriately controlling the rotational speed of the roller, the low link movement of the ink can be influenced, and the ink roll can be optimized to allow the ink to drop into the opening of the screen plate and fully fill the opening. Because the links can be obtained, images with sharper and more uniform ink thickness can be printed on the printing surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic view of the main parts showing the configuration of one embodiment of the present invention, FIG. 2 is a perspective view of the main parts of the same embodiment, and FIGS. 3 to 8 are rollers used in the same embodiment. 9 is an explanatory diagram for explaining the measurement location of the ink thickness of an image, and FIG. 10 is an explanatory diagram for explaining the ink thickness of an image printed by a conventional screen printing device. The explanatory diagram, FIG. 11, is a schematic diagram of the main parts of a conventional screen printing apparatus. 1... Squeegee holder, 2... Squeegee, 2...
...Electric motor, 3a...Pulley, 4.14
．． 24.34.44.54... Roller, 4a... Boot portion, 5... Heald, 6a, 6b... Supporting metal fittings, 7... Screen plate, 8... Printing material,
8a...printing surface, 9...stand,
10.10a...Ink. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tadashi Wakabayashi Figure 1 Figure 3 Figure 5 Bird Figure 7! PJ4 figure! P36 Figure 8

Claims (1)

[Claims] 1. A screen printing device comprising a screen plate and a squeegee that slides along the top surface of the screen plate to apply ink on the top surface of the screen plate to the printing surface through openings in the screen plate. A screen characterized in that a roller whose rotation speed is controllable for rolling the ink is disposed parallel to the squeegee at a position buried in the ink accumulated in front of the squeegee in the sliding direction. Printing device. 2. The screen printing apparatus according to claim 1, wherein unevenness is formed on the circumferential surface of the roller. 3. The screen printing apparatus according to claim 1 or 2, wherein the roller is made of a hard material having solvent resistance.