JP2005205802A - Screen printing method and screen printing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screen printing method by which a coating agent can be prevented from oozing out of the transfer pattern forming region as much as possible, in transferring a printing pattern formed on a screen to the printing surface of a print object. <P>SOLUTION: The screen printing machine, which is equipped with a screen 10 wherein a printing pattern to be printed on the printing surface of a wiring board 12 is formed on one surface side, is used to coat a coating agent the viscosity of which is adjusted by a volatile solvent on the other surface side of the screen 10 to form a transfer pattern, which is transferred following the printing pattern, comprising the coating agent on the printing surface of the wiring substrate 12. In forming the transfer pattern, a predetermine number of wiring boards 12 are successively transferred on one surface side of the screen 10 to form the transfer pattern on the printing surface of the wiring boards 12 successively transferred. Then, transferring the wiring boards 12 to one surface side of the screen 10 is suspended to prevent the coating agent from oozing out of the transfer pattern forming region and opening one surface side of the screen 10 to separate one surface side of the screen 10 from the printing surface of the wiring substrate 12 for a predetermined time so as to dry the coating agent oozing out of the printing pattern forming region of the screen 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a screen printing method and a screen printing machine. More specifically, the present invention relates to a screen printing machine including a screen having a printing pattern printed on a printing surface of a printing object on one side. A printing object is carried in, a coating agent whose viscosity is adjusted with a volatile solvent is applied to the other surface of the screen, and a transfer pattern made of the coating agent is transferred in accordance with the printing pattern. The present invention relates to a screen printing method and a screen printing machine for forming on a printing surface.

In order to reduce the thickness, increase the number of pins, and reduce the size of the semiconductor device, the following Patent Document 1 proposes the semiconductor device shown in FIG.
In the semiconductor device shown in FIG. 5, the pads 102a, 102a,... Formed on the ends of the wiring patterns 102, 102,. The pad 102a is also provided with solder bumps 106 as external connection terminals.
As described above, the pads 102a, 102a,... Of the pads 102a, 102a,... Formed on the mounting surface of the semiconductor element 104 and the pads 102a, 102a,. An insulating film 108 is formed to cover each.
The semiconductor element 104 bonded to the mounting surface of the semiconductor element 104 of the base substrate 100 by the adhesive layer 110 is electrically connected to the bonding portion 102b of the wiring pattern 102 formed near the peripheral edge of the base substrate 100 by the wire 112. It is connected and sealed with sealing resin 114.
Note that a narrow insulating layer 109 is formed across the wiring pattern 102 in the wiring pattern 102 in which the bonding portion 102b is formed, thereby preventing a short circuit between the wire 112 and the wiring pattern 102.
The semiconductor element 104, the wire 112, and the like are sealed with a sealing resin 114.
Japanese Patent Laid-Open No. 11-54658 (FIG. 21)

When the semiconductor device shown in FIG. 5 is manufactured, the wiring substrate shown in FIG. 6 is formed. In the wiring substrate shown in FIG. 6, the pads 102 a formed at the ends of the wiring patterns 102, 102... Formed on the mounting surface of the semiconductor element 104 are covered with the insulating film 108, and A narrow insulating film 109 is formed across the wiring patterns 102, 102,... In which the bonding portions 102b are formed so as to surround the mounting surface.
In order to form the wiring substrate shown in FIG. 6, first, as shown in FIG. 7A, through holes 105 and 105 for forming solder bumps 106 at predetermined locations on a base substrate 100 made of a flexible film. .. is formed by pressing or laser processing, and then a copper foil 101 is adhered to one side.
Further, as shown in FIG. 7B, the copper foil 101 is patterned to form a wiring pattern 102 in which pads 102a are formed in each of the through holes 105, 105,. In the same manner, an insulating film 108 covering each of the pads 102a, 102a,... And an insulating film 109 crossing the wiring pattern 102 are formed.

When the semiconductor device shown in FIG. 5 is manufactured using the obtained wiring board shown in FIG. 6, after applying predetermined plating to each of the bonding portions 102b, 102b,... Of the wiring board shown in FIG. The semiconductor element 104 is mounted via the adhesive layer 110 formed on the mounting surface.
Next, the semiconductor element 104 mounted on the wiring board and the bonding portion 102 b are electrically connected by the wire 112, and then the semiconductor element 104 and the like are sealed with a sealing resin 114.
Thereafter, solder bumps 106 are formed by mounting solder balls on each of the pads 102a, 102,... And reflowing to obtain the semiconductor device shown in FIG.

The present inventor has shown that the insulating film 108 covering each of the pads 102a, 102a,... And the narrow insulating film 109 across the wiring patterns 102, 102,. An attempt was made on the assumption that the insulating films 108 and 109 can be easily formed by screen printing.
However, when a plurality of wiring boards are sequentially supplied to a screen printing machine and the insulating films 108 and 109 made of solder resist are formed on each wiring board by screen printing, the screen printing is performed on a predetermined number of wiring boards. The solder resist oozes out from the region where the insulating films 108 and 109 are formed. For the insulating film 109 formed so as to cross the wiring patterns 102, 102,..., For example, the bleeding portion 109a is formed on the surface of the wiring pattern 102 as shown in FIGS. In addition, the oozing portion 109a was also formed in the portion where the surface of the base substrate 100 was exposed.
In the wiring board on which such a oozing portion 109a is formed, the insulating films 108 and 109 having a shape to be formed cannot be formed, and the oozing portion 109a is formed in the bonding portion 102b as well as the appearance is inferior. In this case, the portion cannot be plated, and there is a possibility that bonding failure of the wire 112 is caused. For this reason, the reliability of the finally obtained semiconductor device is lowered.
Therefore, it is necessary to inspect all the printed circuit boards printed on the screen, and the printed circuit board in which the range of the bleeding portion 109a exceeds the reference value is treated as a defective product.
In addition, it is necessary to remove and clean the screen of the clean printing machine on which the defective wiring board is formed, and the stop time until the screen printing is restarted becomes long.
Accordingly, an object of the present invention is to provide a screen printing method capable of preventing, as much as possible, the bleeding of the coating agent outside the transfer pattern forming region when the printing pattern formed on the screen is transferred to the printing surface of the printing object. It is to propose a screen printer.

In order to solve the above-mentioned problem, the inventor firstly has an insulating film 108 covering each of the pads 102a, 102a,... And a narrow insulating film 109 across the wiring patterns 102, 102,. The reason why the solder resist oozes out of the formation region of the screen-printed insulating films 108 and 109 after the screen printing on the predetermined number of wiring boards was examined.
According to this study, when the screen printing is performed a plurality of times, the solder resist exudation is caused by the solder resist gradually adhering to the outside of the print pattern formation region on one side of the screen on which the print pattern is formed. Turned out to be.
In addition, as the distance between the wiring patterns 102, 102,... Adjacent to the wiring pattern 102 becomes narrower, it becomes difficult to sufficiently seal the wiring patterns by the mask portion formed on the one surface side of the screen. For this reason, there is a limit to prevent the solder resist from exuding by sufficiently sealing between the wiring patterns by the mask portion formed on the screen during screen printing.
On the other hand, the present inventor has found that the solder resist used for screen printing is usually adjusted in viscosity with a volatile solvent, and is dried and solidified by scattering the volatile solvent in the solder resist.
For this reason, the present inventor, on one side of the screen, scatters the volatile solvent in the solder resist adhering to the outside of the print pattern formation area and dries it. As a result of studying that it is possible to prevent the solder resist from exuding to the outside of the transfer pattern formation region formed on the surface, the present invention has been achieved.

  That is, the present invention uses a screen printing machine including a screen on which one side of a printing pattern to be printed on a printing surface of a printing object is used, and carries the printing object on one side of the screen, When a transfer pattern made of the coating agent is applied on the other surface side of the printing object by applying a coating agent adjusted in viscosity with a volatile solvent and transferred in accordance with the printing pattern, the screen is formed. When a predetermined number of the printing objects are sequentially carried on one surface side and the transfer pattern is formed on the printing surface of the sequentially loaded printing objects, the coating agent oozes out of the transfer pattern forming area. In order to prevent this, the application agent which stopped carrying in to the one surface side of the screen of the printing object, opened the one surface side of the screen, and oozed out of the print pattern formation area of the screen As drying is between the printing surface of the one side and the object to be printed the screen in a screen printing method characterized by spaced predetermined time.

  Further, the present invention provides a screen on which a print pattern to be printed on a print surface of a print object is formed on one surface side, contact / separation means for contacting and separating the one surface side of the screen and the print surface of the print object, The printing surface of the printing object that is in contact with the one surface side by applying a coating agent whose viscosity is adjusted with a volatile solvent to the other surface side of the screen on which the printing surface of the printing object is in contact with the one surface side A squeegee that forms a transfer pattern made of the coating agent that is transferred in accordance with the printing pattern, and a printing object that is transferred to the contacting / separating means and that has the transfer pattern formed on a printing surface. A screen printing machine having a conveying means for carrying out from the contacting / separating means, wherein when the transfer pattern is formed on each printing surface of a predetermined number of the printing objects carried into the contacting / separating means, the printing object If you stop importing things Further, the one side of the screen and the printing surface of the printing object are separated from each other for a predetermined time, the one side of the screen is opened, and the coating agent that has oozed out of the print pattern formation area of the screen is dried. The screen printing machine is characterized in that a control unit for controlling the conveying means and the contacting / separating means is provided.

In the present invention, as the screen, a mesh-like screen in which a print pattern including an opening part in which the mesh body is exposed on the bottom surface can be suitably used for a mask part made of resin formed on one surface side of the mesh body.
Further, the separation time between the one surface side of the screen and the printing surface of the printing object is determined so that the coating agent in the print pattern formation region formed on the screen is in an undried state and bleeds out of the print pattern formation region. By setting the time for the applied coating agent to be in a dry state, the screen printing can be resumed smoothly after the opening of one side of the screen is completed.
In addition, the reliability of the wiring board finally obtained can be improved by using the wiring board in which the wiring pattern was formed in the printing surface as a printing target object.

According to the present invention, when a transfer pattern that is transferred in accordance with the print pattern is formed on each print surface of the predetermined number of print objects, the carrying of the print object to one surface side of the screen is stopped, and the screen One side is opened for a predetermined time, and the coating agent that has oozed out of the screen print pattern forming area is dried.
Therefore, when the screen printing is resumed and the portion outside the print pattern formation area formed on the screen comes into contact with the printing surface of the print object, the coating agent adhering to this portion is dried. It is not transferred to the printing surface of the object, and it is possible to prevent the coating agent from oozing out of the transfer pattern forming area.
As a result, a transfer pattern having substantially the same shape as the print pattern formed on the screen can be formed on the print surface of the print object.

An example of a screen printing machine according to the present invention is shown in FIG. In the screen printing machine shown in FIG. 1, a screen 10 on which a printing pattern to be printed on a printing surface of a wiring board 12 as a printing object is formed on one side is fixed to a frame 10a. The frame 10a is fixed at a predetermined position.
As shown in FIG. 2, the screen 10 is composed of a net 10b, and a print pattern 16 is formed on the mask portion 14 formed on one side thereof. The print pattern 16 includes an opening through which the net 10b is exposed. This is a mesh-like screen (hereinafter sometimes simply referred to as a screen 10).

As a contact / separation means for contacting / separating one side of the screen 10 on which the printing pattern 16 shown in FIG. 2 is formed and the printing surface of the wiring board 12, the screen printing machine shown in FIG. The X table 18 that moves, the Y table 20 that is placed on the X table 18 and moves by the drive motor 20a in the Y direction that is perpendicular to the X direction, and the table that is placed on the Y table 20 22 are provided. A mounting table 24 is mounted on the table 22, and the mounting table 24 is moved up and down in the vertical direction with respect to the X table 18 and the Y table 20 by a drive motor 22 a provided on the table 22.
By moving the mounting table 24 up and down, the printed surface of the wiring board 12 mounted on the mounting table 24 can be brought into and out of contact with one surface of the screen 10.
A wiring pattern is formed on the printed surface of the wiring board 12.

  In this way, the coating agent is applied to the other surface side of the screen 10 where the printed surface of the wiring board 12 placed on the placing table 24 is brought into contact with or separated from the one surface side, and is brought into contact with one surface side of the screen 10. A pair of squeegees 26a and 26b for transferring the printing pattern to the printing surface of the printing object is provided. The pair of squeegees 26a and 26b can be moved in the left-right direction along the screen 10 by a squeegee driving means 30 having a drive motor 30b for rotationally driving the ball screw 30a in the left-right direction. , 28b so as to be able to contact and separate from the other surface side of the screen 10. For this reason, when the squeegees 26a and 26b move in the right direction of the drawing, the tip of the squeegee 26a abuts on the other surface side of the screen 10, and when the squeegees 26a and 26b move in the left direction of the drawing, The tip of the squeegee 26b contacts the other surface side of the screen 10.

In the screen printing machine shown in FIG. 1, a carry-in conveyor 32 driven by a drive motor 32 a is used as a conveyance means for carrying the wiring board 12 into the mounting table 24 and carrying out the screen-printed wiring board 12 from the mounting table 24. And a carry-out conveyor 34 driven by a drive motor 34a.
The drive motors 18a, 20a, 22a, 30b, 32a, 34a and the cylinders 28a, 28b provided in the screen printing machine shown in FIG.

When screen printing is performed on the printed surface of the wiring board 12 using the screen printing machine shown in FIG. 1, the drive motor 32 a is driven by a signal from the control unit 36 and the carry-in conveyor 32 is mounted on the mounting table 24. After the placement, the placed wiring board 12 is driven by the drive motors 18a and 20a according to a signal from the control unit 36, and the X table 18 and the Y table 20 are moved to position the wiring board 12.
Next, the drive motor 22 a is driven by a signal from the control unit 36 to raise the mounting table 24, and the printed surface of the wiring board 12 mounted on the mounting table 24 is brought into contact with one surface side of the screen 10.
Further, the control unit 36 transmits a drive signal to one of the cylinders 28a and 28b, abuts one end of the squeegee 26a and 26b on the other surface side of the screen 10, and then drives the drive motor 30a to drive the squeegee. One of 26 a and 26 b is moved along the screen 10, and a coating agent whose viscosity is adjusted with a volatile solvent is applied to the other surface side of the screen 10.
The coating agent applied to the other surface side of the screen 10 passes through the mesh constituting the screen 10 and is formed on the one surface side of the screen 10, and the printing pattern 16 shown in FIG. 2 and the printing surface 12 a of the wiring board 12. It is filled between. On the other hand, the coating agent is not applied to the contact surface of the printed surface of the wiring substrate 12 that contacts the mask portion 14 formed on the one surface side of the screen 10. For this reason, when the drive motor 22a is driven by the signal from the control unit 36 to lower the mounting table 24 and the wiring board 12 and the screen 10 are separated from each other, the printed pattern 16 is formed on the printed surface of the wiring board 12. A transfer pattern made of a coating agent transferred in accordance with the above is formed.
Thereafter, the screen printed wiring board 12 placed on the placing table 24 is carried out by the drive motor 34a of the carry-out conveyor 34 driven by a signal from the control unit 36.

In this way, when screen printing is sequentially performed on each printing surface of the plurality of wiring boards 12, an application agent adhesion portion 38 is formed in the vicinity of the peripheral edge of the printing pattern 16 of the mask portion 14 as shown in FIG. . When the adhering portion 38 comes into contact with the printed surface of the wiring board 12, 12,..., A bleeding portion 109a shown in FIG.
The adhering portion 38 moves one of the squeegees 26 a and 26 b, for example, the squeegee 26 a along the screen 10, and applies the coating agent whose viscosity is adjusted with a volatile solvent to the other surface side of the screen 10. This is considered to be due to the squeegee 26a being pressed against the other side of the screen 10 by applying a predetermined pressure.
That is, when the printed surface 12a of the wiring substrate 12 is brought into contact with one surface side of the screen 10, a wiring pattern or the like is formed on the printed surface 12a of the wiring substrate 12, and the mask portion 14 and the printed wiring substrate 12 are printed. It is extremely difficult to bring the entire surface into contact with the surface 12a. For this reason, when the coating agent of a predetermined pressure is filled between the printed pattern 16 and the printed surface 12a of the wiring board 12 by the squeegee 26a, the adhesion between the mask portion 14 and the printed surface 12a of the wiring board 12 is insufficient. When the coating agent gradually enters between the mask portion 14 and the printed surface 12a of the wiring board 12 from a certain location and screen printing is performed on a predetermined number of wiring boards 12, the bleeding portion 109a shown in FIG. The adhesion part 38 to be formed is formed.

Since it is difficult for the adhering portion 38 to sufficiently bring the entire surface of the mask portion 14 and the printed surface 12a of the wiring substrate 12 into close contact with each other, it is extremely difficult to eliminate the adhering portion 38 only by devising the mask portion 14. is there.
However, since the viscosity of the coating agent is adjusted with a volatile solvent, it can be dried in a short time by scattering the volatile solvent.
For this reason, in the screen printing machine shown in FIG. 1, when a predetermined number of wiring boards 12 are screen-printed and the adhesion part 38 shown in FIG. 3 is formed on the mask part 14, it is driven by a signal from the control part 36. The motor 32a is stopped to stop the carry-in of the wiring board 12 to the one surface side of the screen 10, and the one surface side of the screen 10 and the printed surface of the wiring substrate 12 are separated to open the one surface side of the screen 10. State. By holding the state in which one side of the screen 10 is opened for a predetermined time, the volatile solvent of the coating agent that forms the adhesion portion 38 can be scattered and dried. Even if the dried adhering portion 38 comes into contact with the printed surface of the wiring substrate 12 again, it is not transferred to the printed surface, and the formation of the exuded portion 109a shown in FIG. 9 can be prevented.
Note that the degree of drying of the attaching part 38 may be a state where only the surface of the attaching part 38 is dry.

Here, the time during which the one surface side of the screen 10 is opened is the coating agent formed in the printed pattern 16 formed on the one surface side of the screen 10 in an undried state, and the coating formed in the vicinity of the periphery of the printed pattern 16. It is preferable to set a time during which the adhering portion 38 made of the agent can be dried. If the coating agent in the printing pattern 16 is also dried, when the screen printing is resumed, the printing pattern 16 is not sufficiently filled with the coating agent, and printing failure tends to occur.
The timing at which one side of the screen 10 is opened varies depending on the type and viscosity of the coating agent, the shape of the wiring pattern formed on the printed surface of the wiring board 12, and is preferably obtained experimentally in advance. .

In the above description, the case where screen printing is performed on the printed surface of the wiring board 12 has been described. However, the present invention can be applied to other than the printing of the wiring board 12.
Moreover, although the mesh-shaped screen has been used as the screen 10, a metal screen can be used.
Further, the screen 10 may be provided so as to be lifted and lowered, and the contact state between the one surface side of the screen 10 and the wiring board 12 may be released, and one end of the screen 10 may be provided so as to be lifted and lowered relative to the other end. .

A screen printing machine shown in FIG. 1 is used to screen-print a solder resist whose viscosity is adjusted by a volatile solvent on the printed surface of the wiring board 12, and the pads 102a, 102a,. An insulating film 108 covering each of them and a narrow insulating film 109 crossing the wiring patterns 102, 102... Were formed.
In the wiring substrate shown in FIG. 6, the length from the insulating film 109 (hereinafter referred to as the oozing) of the oozing portion 109a shown in FIGS. 8 (a) and 8 (b) formed by oozing out the solder resist from the insulating film 109 is formed. A wiring board having a length of 200 μm or less can be treated as a non-defective product, but a wiring board having a length of the oozing portion 109a exceeding 200 μm is treated as a defective product. For this reason, in the wiring board shown in FIG. 6, the reference value of the length of the bleeding portion 109a is 200 μm.
When the insulating film 109 is formed on the wiring substrate shown in FIG. 6 by screen printing, the screen of the five wiring substrates 12 is continuously printed so that the length of the bleeding portion 109a is not more than the reference value. While stopping printing, the mounting table 24 was lowered to separate the one surface side of the screen 10 from the printed surface of the wiring board 12, and the one surface side of the screen 10 was opened. When the printed surface of the fifth wiring board 12 was observed, as shown in FIG. 4, the length of the bleeding portion 109a was not more than the reference value.
After the open state of the one surface side of the screen 10 is continued for about 30 seconds, the screen printing is resumed, and after the five wiring boards 12 are continuously screen printed, the screen printing is stopped again, and the screen 10 The one surface side of the screen 10 was separated from the printed surface of the wiring board 12, and the one surface side of the screen 10 was left open for 30 seconds.
In this way, when the operation of making one side of the screen 10 open for 30 seconds is performed after screen printing of the five wiring boards 12 in succession, bleeding occurs on each printing surface of the 400 wiring boards 12. The insulating film 109 in which the length of the protruding portion 109a is equal to or less than the reference value can be formed.

Comparative example

On the other hand, when the screen printing was performed on the printed surface of the wiring board 12 in the same manner as in the example except that the operation for opening one side of the screen 10 was not performed, the printing was completed as shown in FIG. On the printed surface of each wiring board 12, the length of the oozing portion 109a increases linearly. When the insulating film 109 is formed on the printing surface of the twelfth wiring board 12, the length of the oozing portion 109a is The reference value has been exceeded.
As described above, when the length of the bleeding portion 109a exceeds the reference value on the printed surface of each wiring board 12 that has been printed, this wiring board is treated as a defective product.
Further, in this case, it is necessary to remove and clean the screen 10, and the stop time until the screen printing is resumed becomes long.

It is the schematic explaining an example of the screen printer concerning this invention. It is a fragmentary sectional view explaining the screen used for the screen printer of FIG. It is a fragmentary sectional view explaining the state which the coating agent adhered to the mask part of the screen shown in FIG. In the middle of printing, when the operation to open one side of the screen was added and when this operation was not added, the length of the extruding part from the insulating film on the printed surface of each printed wiring board It is a graph which shows the result of having evaluated the thickness. It is a fragmentary sectional view explaining an example of a semiconductor device. FIG. 6 is a front view of a wiring board forming the semiconductor device shown in FIG. 5. It is process drawing explaining the manufacturing process of the wiring board shown in FIG. It is explanatory drawing explaining the bleeding part formed by screen printing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Screen 10a Frame 10b Net body 12a Print surface 12 Wiring board 14 Mask part 16 Print pattern 18 X table 18a, 20a, 22a, 30b, 32a, 34a Drive motor 20 Y table 22 Table 24 Mounting base 26a, 26b Squeegee 28a, 28b Cylinder 30 Squeegee driving means 30a Ball screw 32 Carry-in conveyor 34 Carry-out conveyor 36 Control unit 38 Adhering part

Claims (8)

Using a screen printing machine including a screen on which a printing pattern to be printed on a printing surface of a printing object is formed on one side,
A transfer made of the coating agent, in which a printing object is carried on one side of the screen, a coating agent whose viscosity is adjusted with a volatile solvent is applied to the other side of the screen, and transferred in accordance with the printing pattern. When forming the pattern on the print surface of the print object,
When a predetermined number of the printing objects are sequentially carried on one surface side of the screen, and the transfer pattern is formed on the printing surface of the sequentially loaded printing objects, the spreading of the coating agent outside the transfer pattern forming area In order to prevent sticking out, the carrying of the printing object to one side of the screen is stopped, the one side of the screen is opened, and the coating agent that has oozed out of the printing pattern forming area of the screen is dried. As described above, the screen printing method is characterized in that the one surface side of the screen and the printing surface of the printing object are separated from each other for a predetermined time.   2. The screen printing method according to claim 1, wherein the screen is a mesh screen in which a mask pattern made of a resin formed on one surface side of a mesh body is formed with a print pattern including an opening portion where the mesh body is exposed on the bottom surface.   The separation time between the one surface side of the screen and the printing surface of the printing object is such that the coating agent in the print pattern formation region formed on the screen is in an undried state and oozes out of the print pattern formation region. The screen printing method according to claim 1 or 2, wherein the time for setting the coating agent to a dry state is set.   The screen printing method as described in any one of Claims 1-3 using the wiring board by which the wiring pattern was formed in the printing surface as a printing target object. A screen on which a printing pattern to be printed on the printing surface of the printing object is formed on one side, contact / separation means for contacting and separating one side of the screen and the printing surface of the printing object, and the printing surface of the printing object Is applied to the other surface side of the screen that is in contact with the one surface side, and a coating agent whose viscosity has been adjusted with a volatile solvent is applied to the printing surface of the printing object that is in contact with the one surface side. The squeegee forming the transfer pattern made of the coating agent, which has been copied, and the printing object are carried into the contacting / separating means, and the printing object having the transfer pattern formed on the printing surface is carried out from the contacting / separating means. A screen printing machine comprising conveying means,
When the transfer pattern is formed on each printing surface of the predetermined number of the printing objects carried into the contacting / separating means, the loading of the printing objects is stopped, and the one surface side of the screen and printing of the printing objects are performed. The conveying means and the contacting / separating means are controlled so that the coating agent is separated from the surface for a predetermined time, and the one surface side of the screen is opened to dry out the coating agent that has oozed out of the print pattern formation area of the screen. A screen printing machine comprising a control unit for performing the above-described operation.   6. The screen printing machine according to claim 5, wherein the screen is a mesh-like screen in which a printing pattern including an opening portion through which the mesh body is exposed is formed on a bottom surface of a mask portion made of a resin formed on one surface side of the mesh body.   The control unit determines the time for separating the one surface side of the screen from the printing surface of the printing object, and the coating agent in the print pattern formation region formed on the screen is in an undried state, The screen printing machine according to claim 5 or 6, wherein the conveying means and the contacting / separating means are controlled so that a time during which the coating agent that has oozed out of the formation area can be dried is reached.   The screen printing machine according to any one of claims 5 to 7, wherein the printing object is a wiring board having a wiring pattern formed on a printing surface.

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