JPH10138455A - Print head in screen printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brand new print head having doctor function and squeegee function and incorporating a rotary drum for paste chamber to be filled with paste. SOLUTION: The print head comprises a print head body 2 being set reciprocally and movably up and down on a screen while containing an inscribing rotary drum 5 for paste chamber, and a squeegee 3 fixed to the front end part of reciprocation movably up and down with respect to the head body. The head body has a paste throw-in port 8, partition walls A, 9B, a paste coating flow-out port 10, and an excess paste collecting port 11. The rotary drum 5 for paste chamber has a paste throw-in drum opening 13 communicating with the paste throw-in port at a neutral angular position AN, and a paste flow in/out drum opening 14 partitioned by the partitioning walls at the neutral angular position and communicating with the paste coating flow-out port and the excess paste collecting port, respectively, at a first angular position Ap1 and a second angular position Ap2 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of a print head in a screen printing apparatus,
In a print head provided with a doctor and a squeegee, the paste applied on the screen during the paste application step of applying paste on the screen by the doctor and applying the printing pressure through the screen by the squeegee onto the printing surface of the printing material. The present invention relates to a print head in a screen printing apparatus capable of preventing air from entering a paste as much as possible during a printing step of transferring.

[0002]

2. Description of the Related Art As is well known, a screen printing apparatus for screen printing includes a screen having an image portion for transparently extruding a paste, a non-image portion for blocking the transparent extrusion of a paste, and this screen. On the other hand, a support means for receiving the printing material such that the printing surface of the printing material faces the screen gap G, and a printing head provided with a doctor and a squeegee are arranged on the screen so as to be capable of reciprocating scanning. The print head is reciprocally scanned on the screen with the paste filled in the area defined by the doctor, the squeegee, and the screen, the doctor applies the paste on the screen during the forward scan, and the squeegee during the backward scan. The paste applied on the screen is applied to the printing surface of the printing It is obtained by configured to print processing by transferring the above.

[0003] In this screen printing, since the paste is directly extruded through the screen onto the printing surface of the printing material, it is characterized in that the deposition layer (printing layer) can be extremely thick. In addition, since the printing principle is very simple and the printing device is simple, it can be used for all materials, such as paper, fibers, metals, glassware, pottery, wood, plastic, leather, etc. It is often used as an effective printing.

[0004]

The principle of screen printing by a conventional screen printing apparatus will be described with reference to FIG. In the screen printing apparatus shown in the figure, a screen 31 is arranged on a printing surface Ha of a printing material H with a screen gap G therebetween, and a printing head 32 having a doctor 33 and a squeegee 34 can reciprocally scan on the screen 31. It is located in. On the screen 31,
The paste P is filled in an area 35 defined by the doctor 33, the squeegee 34, and the screen 31,
The print head 32 is configured to reciprocally scan on the screen 31 in a state where the paste P is filled in the area 35.

[0005] In the running scan of the print head 32, FIG.
At the time of scanning in the direction of arrow M in FIG.
1 is evenly applied in a desired amount. Hereinafter, the forward scanning of the print head 32 is referred to as a paste application step (FIG. 3).
B).

On the other hand, as shown in FIG.
At the stage when the paste application process by forward scanning of
As shown in FIG. 3C, the doctor 33 in the print head 32 rises and the squeegee 34 descends to
A printing pressure is applied over the printing material H to bring the screen 31 into contact with the printing surface Ha of the printing material H.

FIG. 3 shows the scanning of the print head 32 during traveling.
At the time of scanning in the direction of arrow N in D, that is, at the time of backward scanning, the paste applied on the screen is transferred onto the printing surface of the printing material while applying printing pressure through the screen by the squeegee 34, and excess paste is collected. . Hereinafter, the backward scanning of the print head 32 is referred to as a printing process (see FIG. 3D).

In the above-described screen printing by the conventional screen printing apparatus, during the paste application step by the doctor 33, and further, during the printing step by the squeegee 34, especially in the former case, as shown in FIG. The swirl W that entrains the air in the paste P stored above was generated, and the air was easily mixed into the paste P. If air is mixed into the paste P in this manner, a pattern defect after printing occurs, which has been pointed out as the greatest difficulty in the printing process.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned drawbacks or problems of the conventional screen printing. The present invention has a doctor function and a squeegee function and is used for a paste chamber for filling a paste therein. By providing a completely new print head with a rotating drum, the paste in the rotating drum for the paste chamber is configured to flow in a certain direction during the entire process of applying the paste onto the screen and printing. Accordingly, it is an object of the present invention to provide a novel print head capable of reducing the air entrainment phenomenon as much as possible and providing a paste having a stable viscosity by flow kneading to a printing surface.

[0010]

According to the present invention, in order to achieve the above object, specifically, a screen is arranged on a printing surface of a printing material with a screen gap therebetween,
A print head having a doctor and a squeegee is arranged on the screen so as to be capable of reciprocating scanning, and the print head is reciprocated on the screen in a state where paste is filled in an area defined by the doctor, the squeegee and the screen. Scan, apply the paste on the screen by the doctor at the time of forward scanning, and transfer the paste applied on the screen to the printing surface of the printing object while applying printing pressure over the screen by the squeegee at the time of backward scanning. In a screen printing apparatus adapted to perform a printing process, a print head body having a cavity which is set so as to be capable of reciprocating scanning movement and up and down movement on the screen and in which a rotary drum for a paste chamber is inscribed and rotatably accommodated therein. And an upper edge of the print head main body with respect to the head main body at a forward movement leading edge of the print head main body. A squeegee movably mounted, wherein the print head main body includes a paste input port communicating with the cavity at an upper portion, and a partition wall extending inside and outside the cavity at a lower portion, wherein the partition wall has On the other hand, the paste application outlet communicating with the cavity at a first angular position on the forward trailing edge side of the print head main body, and communicating with the cavity at a second angular position on the forward leading edge side of the print head main body below. An excess paste collecting port, wherein the paste chamber rotary drum includes a paste input drum opening communicating with the paste input port when the paste chamber rotary drum is at a neutral angle position; When the drum is at the neutral angle position, the drum is partitioned by the partition wall. A paste inflow / outflow drum opening which communicates with the opening and which communicates with the surplus paste recovery port when in the second angular position. Applying on the screen through the outlet, and collecting the excess paste on the screen during the backward scanning of the print head into the rotating drum through the excess paste collecting port,
A print head in a screen printing apparatus is configured so that the flow of the paste in the rotary drum can be directed in the same direction during the reciprocal scanning of the print head.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a print head in a screen printing apparatus according to the present invention will be described in detail based on a specific embodiment shown in the drawings. FIG. 1 is a schematic side sectional view showing a specific example of a main component of a print head in a screen printing apparatus according to the present invention, and FIG. FIG. 2A is a schematic side cross-sectional view illustrating an aspect of a paste filling step of filling a paste into a paste chamber rotating drum (the same applies to a screen replacement step) for explaining an operation mode. , FIG. 2B
FIG. 2C is a schematic side sectional view showing an aspect of a paste application step, and FIG. 2C is a schematic side sectional view showing an aspect of a printing step using a squeegee.

The screen printing apparatus according to the application of the present invention basically has a screen S disposed on a printing surface Ha of a printing material H with a screen gap G therebetween, and reciprocally scans the print head 1 on the screen S. It is arranged as possible.
Print head 1 for screen printing characterized by the present invention
Is constituted by a combination structure including the print head main body 2 and the squeegee 3. The print head body 1
Has a length dimension comparable to the width dimension of the screen S, and is capable of reciprocating scanning in a forward movement direction M and a backward movement direction N by reciprocating scanning drive means (not shown), and It is assembled so as to be able to move up and down along the up and down direction X by up and down driving means (not shown). The drive source for the reciprocating scanning drive unit may be constituted by, for example, a servomotor, and the drive source for the vertical drive unit may be constituted by, for example, a cylinder.

The print head main body 2 has a cavity 4 having an inner diameter r ₁ extending in the longitudinal direction inside the main body, and a paste chamber rotary drum 5 having an outer diameter R ₁ is provided in the cavity 4. It can be rotatably accommodated in the inscribed state. Side plate members 6 are attached to both ends of the print head main body 2 in the longitudinal direction so that the paste P can be prevented from leaking sideways during the paste application step described later, and the paste can be collected. It is configured in.

The forward movement leading edge 2a side of the print head body 2 is formed by an inclined surface 7 for supporting the squeegee 3, and the squeegee 3 is attached to the head body 2 by a unique cylinder or the like. Tilt up / down direction (arrow Y
Direction).

In the present invention, the print head main body 2
Is a paste input port 8 communicating with the cavity 4 in the upper portion 2c.
And partition walls 9A and 9B extending inside the cavity 4 and outside the cavity 4 toward the lower portion 2d.
Wherein the paste coating outlet 10 communicating with the cavity 4 in the first angular position A _P1 after edge 2b side forward movement of the print head body 2, before the forward movement of the print head body 2 to the lower edge relative to the 2
A surplus paste recovery port 11 communicating with the cavity 4 is provided at the second angular position _AP2 on the a side. In the above configuration,
The part indicated by reference numeral 12 functions as a doctor.

[0016] On the other hand, the paste chamber rotary drum 5, a paste-up drum opening 1 in communication with the paste inlet 8 when the rotational drum 5 for the paste chamber is in the neutral angular position A _N as shown in FIG. 1
3, the partition wall 9A when the paste chamber rotary drum 5 is in the neutral angular position A _N, 9B
And a paste inflow / outflow drum that communicates with the paste application outlet 10 when in the first angular position A _P1 and communicates with the surplus paste recovery port 11 when in the second angular position A _P2. It has an opening 14. The paste chamber rotary drum 5 includes:
For example, the rotation drive source such as a stepping motor, are constituted in a clockwise direction T ₁ and counterclockwise T ₂ so as to be forward and backward inversion turning.

Next, the operation of the print head 1 for screen printing according to the present invention will be described in detail with reference to FIGS. 2A to 2C. FIG. 2A shows a mode of a paste filling step of filling the paste P into the paste chamber rotary drum 5 (the same applies to a screen replacement step). In this case, the paste chamber rotary drum 5 is set at a neutral angle. The paste input drum opening 13 is set at the position A _N and the paste input drum opening 13 is aligned with the paste input port 8 and opened.
4 is partitioned by partition walls 9A and 9B.

In this state, the paste P is supplied from the paste input port 8 and the paste input drum opening 13 into the paste chamber rotary drum 5. In this case, the paste application outlet 10 and the surplus paste recovery port 11 are
Since the paste P is blocked by the wall of the paste chamber rotary drum 5, the supplied paste P does not flow out and does not flow out. Therefore, if the screen replacement operation is performed in this state, the paste P does not flow onto the screen.

[0019] Figure 2B is for illustrating the embodiments of the paste applying step, a state where the rotary drum 5 for the paste chamber is pivoted from the neutral angular position A _N clockwise T _1, is set to the first angular position A _P1 Is shown.
In this case, since the paste inflow / outflow drum opening 14 of the paste chamber rotary drum 5 and the paste application outlet 10 in the print head main body 2 are aligned, the outflow of the paste P in the paste chamber rotary drum 5 is prevented. acceptable, with the scanning movement in the forward scanning direction M of the print head body 2, and flows out the paste P on the screen 1, to form a paste coating layer P _L on the screen 1. In this case, the paste P of the paste chamber rotary drum 5, flows toward the counterclockwise direction as shown by the arrow K _1.

FIG. 2C shows a mode of a printing process using the squeegee 3 after the paste application process is completed. The paste chamber rotating drum 5 is moved counterclockwise T ₂ from the first angular position _AP 1. A state is shown in which the _user has turned and set to the second angular position _AP2 . In this case, since the paste inflow / outflow drum opening 14 of the paste chamber rotary drum 5 and the excess paste recovery port 11 in the print head main body 2 are aligned, the print head main body 2
With the scanning movement in the backward scanning direction N, the excess paste P among the pastes P applied on the screen 1 is collected. In this case, the excess paste P
It is toward the paste chamber rotary drum 5, flows toward the counterclockwise direction as indicated by arrow K _2.

[0021]

As described above, according to the print head 1 for screen printing according to the present invention, the paste P in the paste chamber rotary drum 5 is supplied to the paste application outlet 10 during the forward scanning of the print head 1. Through the screen S
The excess paste on the screen S is collected in the paste chamber rotating drum 5 through the excess paste collecting port 11 during the backward scanning of the print head 1, and during the reciprocating scanning period of the print head 1, The flow of the paste P in the rotating drum 5 for the paste chamber can be directed in the same direction K _{1 and} K ₂ , thereby preventing air from entering the flowing paste P as much as possible. it can. Therefore, it is possible to surely solve the problem of the pattern defect after printing, which is caused by the incorporation of air into the paste P and the like, and the paste kneading in the rotating drum 5 for the paste chamber has a stable paste viscosity. It can be said that it works very effectively in terms of keeping it.

Further, according to the print head 1 for screen printing according to the present invention, since there is no remaining paste on the screen S, the work of replacing the screen S can be performed quickly, and the labor of the screen printing work can be reduced. It can be said that this works extremely effectively also in that the screen S can have a longer life.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view showing a specific embodiment of a main component of a print head in a screen printing apparatus according to the present invention.

FIG. 2 shows a print head according to the present invention;
FIG. 2A is a view for explaining an operation mode thereof.
FIG. 2B is a schematic side sectional view showing an aspect of a paste filling step of filling a paste into the paste chamber rotating drum (the same is also applied to a screen exchange step of exchanging a screen), and FIG. FIG. 2C is a schematic side sectional view showing an aspect of a printing process using a squeegee.

FIG. 3 is a schematic side view for explaining an operation mode of the conventional screen printing in the screen printing apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 print head 2 print head body 3 squeegee 4 cavity 5 rotating drum for paste chamber 8 paste inlet of print head body 9A, 9B partition wall of print head body 10 paste application outlet of print head body 11 excess paste of print head body Collection port 12 Doctor unit 13 Paste loading drum opening 14 Paste inflow / outflow drum opening S Screen H Print material Ha Print surface of print material H G Screen gap P Paste M Forward scan direction of print head N Reverse scan direction of print head A _N Neutral angle position A _P1 First angle position A _P2 Second angle position

Claims (1)

[Claims] A screen is arranged on a printing surface of a printing material with a screen gap therebetween, and a printing head having a doctor and a squeegee is arranged on the screen so as to be reciprocally scanable. The print head is reciprocally scanned on the screen in a state where the paste is filled in the area defined by the above, the paste is applied on the screen by the doctor during the forward scan, and the squeegee passes over the screen during the backward scan. In a screen printing apparatus in which the paste applied on the screen is transferred onto the printing surface of the printing material while performing printing processing while applying printing pressure to the screen, the screen is set to be capable of reciprocating scanning and up and down movement on the screen, The cavity for rotatably housing the paste chamber rotary drum A print head main body, and a squeegee attached to the forward movement front edge of the print head main body so as to be vertically movable with respect to the head main body, wherein the print head main body has a paste input port communicating with the cavity at an upper part. A paste application outlet communicating with the cavity at a first angular position on the forward trailing edge side of the print head main body with respect to the partition wall. And a lower portion provided with a surplus paste recovery port communicating with the cavity at a second angular position on the forward leading edge side of the print head main body, wherein the paste chamber rotating drum is such that the paste chamber rotating drum has a neutral angle. The paste input drum opening communicating with the paste input port when in the position, and the paste chamber rotary drum are in the neutral angular position. A paste inflow / outflow drum opening that is partitioned by the partition wall and communicates with the paste application outlet when in the first angular position and communicates with the surplus paste recovery port when in the second angular position And applying the paste in the rotating drum to a screen via a paste application outlet during forward scanning of the print head,
Excess paste on the screen can be collected in the rotating drum through the excess paste collecting port during the backward scanning of the print head, and the flow of the paste in the rotating drum can be directed in the same direction during the reciprocating scanning of the printing head. A print head in a screen printing apparatus characterized by the above.