JP4763466B2 - Screen printing device - Google Patents

Description

  The present invention relates to a screen printing apparatus for applying paste such as cream solder to a substrate such as a printed circuit board.

  Conventionally, the substrate formed on the stage and the mask sheet are overlaid, and the paste formed on the mask sheet, such as cream solder and conductive paste, is expanded with a squeegee, thereby opening the opening formed in the mask sheet. In general, a screen printing apparatus in which a paste is applied (printed) at a predetermined position on a substrate is known (for example, Patent Document 1).

In this type of screen printing apparatus, a rectangular mask sheet main body is assembled to a frame (referred to as a mask holder), and for example, a pair of opposite sides of the mask holder are supported by a mask support section on the apparatus side. By fixing the mask holder, the mask sheet is set on the printing apparatus main body.
JP-A-10-757

  In this type of screen printing apparatus, conventionally, the mask sheet body has a standard size based on the substrate of the maximum size to be printed, and only the shape, number and arrangement of the printing openings correspond to the substrate. It was. Therefore, the mask sheet corresponding to the small-sized substrate has been uneconomical with the printing openings concentrated at the center of the large mask sheet main body assembled to the large mask holder.

  Thus, recently, a mask sheet having a size corresponding to the substrate size as much as possible has been used with emphasis on economy. However, since the support position of the mask sheet differs depending on the mask size, when replacing the mask sheet, after the operator removes and replaces the mask support portion bolted to the apparatus body, the next mask sheet is moved to the apparatus body. Therefore, the mask sheet replacement work is complicated and inefficient.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to be able to cope with a plurality of sizes of mask sheets and more efficiently perform a mask sheet replacement operation.

In order to solve the above problems, the screen printing apparatus of the present invention is provided on a pair of frames arranged in a first direction at a predetermined interval and extending in a second direction orthogonal to the first direction, and these frames, respectively. a device body including a mask support, the screen printing apparatus Ru and a mask sheet to be fixed to the apparatus body in a state of being supported each pair of opposite sides by the mask support, to each of the respective mask support A clamp mechanism that is provided and detachably holds the mask sheet with respect to the mask support portion; and is provided on at least one of the pair of frames to slide the mask support portion in the first direction. Slide drive means, and the slide drive means are spaced apart in the second direction of the frame. A pair of rails that are respectively fixed and movably support the mask support portion in the first direction, and a nut member that is disposed at an intermediate position between the rails and extends in the first direction and is incorporated in the mask support portion. A screw shaft that is screwed into the screw shaft and a motor that rotationally drives the screw shaft, and the motor is driven by rotating the screw shaft by the motor and moving the mask support portion in the first direction. Ru der to hold the mask support at any position or specific positions in the first direction by holding torque when stopping.

According to this printing apparatus, it is possible to at least the other hand slides the side of the pair of mask support for supporting the mask sheet, thereby the distance between the two mask support can be changed. Moreover, the mask sheet replacement operation can be efficiently performed by automating the change in the interval between the mask support portions as described above. Therefore, it becomes possible to easily incorporate a plurality of sizes of mask sheets into the apparatus main body without removing the mask support portion from the apparatus main body and replacing it with another one.
In addition, each mask support part is equipped with a clamp mechanism that detachably holds the mask sheet, so that the mask sheet can be fixed and released from the mask support part easily and quickly by operating the clamp mechanism. Thus, the mask sheet replacement operation can be performed efficiently.

  According to the screen printing apparatus of the present invention, the interval between the mask support portions can be easily changed by sliding at least one side of the pair of mask support portions that support the mask sheet. And the replacement work can be performed more efficiently. Further, since it is not necessary to prepare in advance a plurality of mask support portions corresponding to the mask sheet as in the prior art, it is possible to proceed with the printing operation economically.

  Embodiments of the present invention will be described with reference to the drawings.

  1 and 2 schematically show a screen printing apparatus according to the present invention. FIG. 1 is a side view of the printer with the cover removed, and FIG. 2 is a front view of the screen printing apparatus.

  As shown in these drawings, a printing stage 13 is provided on a base 1 of a screen printing apparatus (hereinafter abbreviated as a printing apparatus), and a printed board P (hereinafter referred to as a board) is provided on both sides of the printing stage 13. An upstream conveyor 12 </ b> A and a downstream conveyor 12 </ b> C for carrying in and out of the printing stage 13 on the printing stage 13 are arranged. In the following description, the conveying direction of the substrate P by the conveyors 12A and 12C is the X-axis direction, the direction orthogonal to this on the horizontal plane is the Y-axis direction, and the direction orthogonal to both the X-axis and Y-axis directions is Z. The description will proceed as an axial direction.

  The printing stage 13 holds the substrate P and positions it from the lower side with respect to the mask sheet 35, which will be described later, and is mainly composed of a main conveyor 12B, a lifting table 28, a substrate clamping mechanism 14 and the like which will be described later. Yes.

  The printing stage 13 is supported by a four-axis unit 20 and is moved to the X axis, the Y axis, the Z axis, and the R axis (rotation about the Z axis) by the operation of the unit 20.

  More specifically, a rail 21 is disposed on the base 1 along the Y-axis direction in a horizontal plane, and a Y-axis table 22 is slidably attached to the rail 21. A ball screw mechanism (not shown) provided on the base 1 is connected to the Y-axis table 22, and the Y-axis table 22 is moved in the Y-axis direction with respect to the base 1 by driving the ball screw mechanism. Is configured to move.

  A rail 23 is disposed on the Y-axis table 22 along the X-axis direction, and an X-axis table 24 is slidably attached to the rail 23. A ball screw mechanism (not shown) provided on the Y-axis table 22 is connected to the X-axis table 24, and the X-axis table 24 is driven with respect to the Y-axis table 22 by driving the ball screw mechanism. Configured to move in the direction.

  An R-axis table 26 is provided on the X-axis table 24 so as to be rotatable around a vertical line (Z-axis direction). The R-axis table 26 is Z with respect to the X-axis table 24 by driving means (not shown). It is designed to rotate around the axis.

  A slide column 27 is slidably attached to the R-axis table 26 along the vertical direction (Z-axis direction), and an elevation table 28 is attached to the upper portion of the slide column 27. A ball screw mechanism 29 is provided between the elevating table 28 and the R-axis table 26. The elevating table 28 is guided to the R-axis table 26 while being guided by the slide column 27 by driving the ball screw mechanism 29. It is configured to move in the Z-axis direction (vertical direction).

  Thus, the 4-axis unit 20 moves the printing stage 13 to the X axis, Y axis, Z axis, and R axis (rotation around the Z axis) by individually driving the tables 22, 24, 26, and 28. It is configured to let you.

  On the lifting table 28, a pair of main conveyors 12B are provided along the X-axis direction, and a substrate clamping mechanism 14, a positioning mechanism 15, a placement table 30, and the like are provided. As described above, the printing stage 13 for holding the substrate P is constituted by the lifting table 28, the main conveyor 12B, and the like.

  The main conveyor 12B moves integrally with the lifting / lowering table 28, and the lifting / lowering table 28 is at a predetermined home position (a lower end position and predetermined in the X-axis, Y-axis, and R-axis directions). In the state set at the origin position), the upstream conveyor 12A and the downstream conveyor 12C are arranged in the X-axis direction. Then, when the elevating table 28 is set to the home position in this way, the substrate P is transferred from the upstream conveyor 12A to the printing stage 13 (main conveyor 12B), and the substrate P is transferred from the printing stage 13 to the downstream conveyor 12C. Is being carried out.

  Each of the conveyors 12A to 12C including the main conveyor 12B includes a pair of front and rear belt conveyors 121 that support both ends of the substrate P, respectively. Each of the pair of belt conveyors is configured such that the interval can be changed by a variable mechanism (not shown) using a servo motor as a drive source. In the present embodiment, the rear belt conveyor 121 is moved toward and away from the front belt conveyor 121 with reference to the front belt conveyor 121 on the front side (the belt conveyor 121 located on the left side in FIG. 1). A variable mechanism is configured, and the conveyors 12A to 12C are configured so that the substrates P having different sizes can be conveyed.

  The substrate clamping mechanism 14 holds the substrate P in a fixed manner during the operation, and has a pair of clamp pieces 140 that extend substantially parallel to the X-axis direction and can be contacted and separated in the Y-axis direction. 140 is configured to fix the substrate P by sandwiching it from both sides.

  As shown in FIGS. 1 and 5, each clamp piece 140 has a clamp piece main body 14 a fixed to the upper surface of the frame 122 of the front belt conveyor 121 with a bolt among the front and rear belt conveyors 121 constituting the main conveyor 12 </ b> B. It is attached by. In addition, a movable portion 124 that moves forward and backward in the Y-axis direction using an air cylinder (not shown) as a drive source is provided on the frame 122 of the rear belt conveyor 121, and the clamp piece main body 14a is bolted to the upper end surface of the movable portion 124. It is attached by doing. Then, the operation of the air cylinder switches between a clamp state in which the rear clamp piece 140 is close to the front clamp piece 140 and a clamp release state in which the rear clamp piece 140 is separated from the front clamp piece 140. The substrate P is sandwiched from both sides in the clamped state.

  Each clamp piece 140 is composed of a clamp piece main body 14a and a joint piece 14b that is detachably connected to both sides of the clamp piece main body 14a, and a mask support that will be described later by detaching the joint piece 14b from the clamp piece main body 14a. The length (dimension in the X-axis direction) of the clamp piece 140 can be changed in accordance with the change in the interval 36.

  More specifically, as shown in FIG. 6, a magnet 141 is embedded and fixed at the center of the end surface (joint surface) of the joint piece 14b, and on both sides (both sides in the Y-axis direction) of the magnet 141. A knock pin 142 projects from each other. On the other hand, a pair of knock holes 144 corresponding to the knock pins 142 are formed in the end surface (joint surface) of the clamp piece main body 14a. Then, the joint piece 14b is positioned with respect to the end face of the clamp piece main body 14a by fitting the joint piece 14b to the end face of the clamp piece main body 14a with no gap while inserting the knock pin 142 into each knock hole 144, and the frame It is fixed by the magnetic force of the magnet 141 while being supported from below by 122.

  Referring back to FIGS. 1 and 2, the positioning mechanism 15 positions the substrate P by regulating the bending of the substrate P and the like before the substrate P is clamped by the substrate clamping mechanism 14. Although this mechanism is not shown in detail, a positioning member 15a that applies a reaction force from above to the substrate P so as to resist the upward pressing of the mounting table 30 at the positioning position (working position), and the positioning member 15a is composed of a drive mechanism that displaces the actuator 15a between an operating position that is pressed against the upper surface of the substrate P and a retracted position (position shown in FIG. 1) outside both the clamp pieces 140. In this state, the positioning member 15a is displaced and fixed at the operating position, and in this state, the placement table 30 is raised and the substrate P is pressed to correct the deflection of the substrate P.

  The mounting table 30 supports the substrate P while correcting the bending of the substrate P by lifting the substrate P on the main conveyor 12B from the lower side. The mounting table 30 is supported by the slide column 31 so as to be movable up and down on the lift table 28, and is connected to a ball screw mechanism (not shown) provided between the table 30 and the lift table 28. The ball screw mechanism is driven to move in the Z-axis direction (vertical direction) with respect to the lifting table 28.

  On the other hand, a mask holding unit 16 and a squeegee unit 17 are disposed above the printing stage 13 and the like.

The mask holding unit 16 detachably holds the mask sheet 35 with respect to the apparatus main body. As shown in FIGS. 3 and 4, both sides of the 4-axis unit 20 (both sides in the X-axis direction) are sandwiched. Are assembled to a pair of elevated frames 2. In this embodiment, the X-axis direction corresponds to the first direction of the present invention, and the Y-axis direction corresponds to the second direction.

  The mask holding unit 16 is supported on a bracket 2a projecting from each frame 2 via a rail 42, which will be described later, and extends in the Y-axis direction (a mask support section according to the present invention). And a mask clamp mechanism 37 provided on each of the mask support bases 36, and a pair of opposing pieces (in the present embodiment, both end edges in the X-axis direction) of the mask sheet 35 are mask support bases. The mask sheet 35 is held by being placed on 36 and clamped by the respective mask clamp mechanisms 37.

  As shown in FIG. 4, the mask clamp mechanism 37 includes a pressure plate 40 that is driven back and forth in an up and down direction by an actuator 39 such as an air cylinder on an inverted L-shaped arm 38 provided on the mask support base 36. It has a configuration. That is, by inserting the mask sheet 35 between the mask support 36 and the pressing plate 40 and driving the pressing plate 40 forward by the operation of the actuator 39, the mask sheet 35 is moved by the pressing plate 40 and the mask sheet 35. It is comprised so that it may clamp in an up-down direction.

  The mask sheet 35 has a structure in which a mask sheet body made of a rectangular metal plate such as SUS having a printing opening is assembled to a rectangular frame (mask holder) along the edge thereof. The mask holder 36 is positioned by, for example, a knock pin (not shown), and the mask holder portion of the mask sheet 35 is clamped by the mask clamp mechanism 37.

  Each mask support 36 is slidable in the X-axis direction with respect to the frame 2 and is driven by a servo motor 45. Specifically, the bracket 2a is provided with a rail 42 extending in the X-axis direction, and a ball screw shaft 44 extending in parallel with the bracket 2a and driven to rotate by a servo motor 45. The ball screw shaft 44 is The nut member 36a assembled to the mask support 36 is screwed and inserted.

With this configuration, when the ball screw shaft 44 is rotationally driven by the servo motor 45, the mask support base 36 moves in the X-axis direction along the rail 42 with the rotation, and the mask support base 36 is shown in FIG. The mask support 36 is configured to be displaced to the retracted position and the advanced position shown in FIG. That, in this embodiment, servomotor 45, the ball screw shaft 44 and rails 42 are you corresponds to the slide driving means according to the present invention.

  The squeegee unit 17 expands the paste such as cream solder and conductive paste supplied on the mask sheet 35 from a nozzle (not shown) while rolling (kneading) the mask sheet 35 on the mask sheet 35.

  As shown in FIGS. 1 to 3, the squeegee unit 17 is fixed on each frame 2 and is mounted in a state of straddling the rails 51 and rails 51 extending in the Y-axis direction. A beam 52 that moves in the Y-axis direction by the mechanism, a pair of squeegees 53 and 53 for expanding the paste on the mask sheet 35, and an elevating mechanism that is provided on the beam 52 and moves up and down the squeegees 53 and 53 individually. During printing, the paste is expanded on the mask sheet 35 by sliding the squeegees 53 and 53 along the surface of the mask sheet 35 alternately while the beam 52 reciprocates in the Y-axis direction. It is configured as follows.

  Next, the function and effect of the printing apparatus having the above configuration will be described.

  First, in this printing apparatus, when printing processing is performed on a large-sized substrate P, the mask support base 36 of the mask holding unit 16 is set in the retracted position, and a large-sized mask sheet corresponding to the large-sized substrate P is set. 35 is set on the mask support 36 and clamped by the mask clamp mechanism 37. Further, the clamp piece 140 of the substrate clamp mechanism 14 is in a state where the joint piece 14b is added (see FIGS. 3 and 5).

  When the printing operation is started, the substrate P is carried onto the printing stage 13, and the substrate P is at the same height position as the surface of the clamp piece 140 of the substrate clamping mechanism 14 (the height indicated by the broken line in FIG. 1). And the substrate P is clamped by the clamp piece 140 in this state. At this time, the clamp piece 140 is in a long state with the joint piece 14b joined to the clamp piece main body 14a as described above, so that the entire large substrate is securely clamped by the clamp piece 140.

  Next, the substrate P held on the printing stage 13 by the operation of the four-axis unit 20 is loaded on the mask sheet 35 from below. At this time, as a result of the mask support base 36 being set in the retracted position as described above, the clamp piece 140 overlaps the lower surface of the mask sheet 35 integrally with the substrate P without causing interference with the mask support base 36. Will be disguised.

  Next, as the squeegee unit 17 moves, the squeegee 53 is disposed above a predetermined work start position, and at the rear of the advancing direction (when moving to the right in FIG. When the squeegee 53 moves to the right, the squeegee 53 located on the right squeegee 53) is set to a height position where it abuts the mask sheet 35.

  Then, after the paste is supplied onto the mask sheet 35 by a supply device (not shown), the paste on the mask sheet 35 is expanded by the squeegee 53 when the squeegee unit 17 moves (forward movement) in the Y-axis direction. It is applied (printed) on the substrate P through the printing openings formed in the mask sheet 35.

  When the squeegee 53 reaches the end position, after the squeegee 53 has moved up, the substrate P is released, the substrate P is replaced with respect to the printing stage 13, and the substrate P is mounted on the mask sheet 35. In the same manner as described above, after the squeegee 53 on the side opposite to the forward movement is set at a height position where the squeegee 53 comes into contact with the mask sheet 35, the squeegee unit 17 moves in the Y-axis direction. As a result, the paste on the mask sheet 35 is expanded.

  Thereafter, the pair of squeegees 53 move along the mask sheet 35 in such a state that the pair of squeegees 53 are alternately in contact with the mask sheet 35, whereby the paste is sequentially applied to the substrate P through the printing openings formed in the mask sheet 35. Is applied (printed).

  In such a printing operation, for example, when the type of the substrate P is changed by lot switching or the like, the operator replaces the mask sheet 35 correspondingly.

  Specifically, for example, by operating a non-illustrated input device (for example, a keyboard or the like) and inputting a clamp release command of the mask clamp mechanism 37, the actuator 39 is operated to retract the pressing plate 40. As a result, the mask clamp mechanism 37 is switched to the clamp release, and in this state, the used mask sheet 35 is removed and replaced with a mask sheet 35 corresponding to the next lot. Then, the mask sheet 35 is clamped by switching the mask clamp mechanism 37 to the clamped state by operating the input device again and inputting a clamp command.

  Note that the above is the case where the size of the mask sheet 35 before and after replacement is the same, and when the mask sheet 35 is changed to a smaller size, after the used mask sheet 35 is removed, first the substrate clamp The piece 14b is removed from each clamp piece 140 of the mechanism 14 to shorten its length. Then, by operating the input device and rotating the ball screw shaft 44 by the servo motor 45, the mask support base 36 is moved to the forward position, thereby switching the interval of the mask support base 36 to a narrow interval.

  Thereafter, as described above, after the next mask sheet 35 is set on the mask support base 36, the mask sheet 35 is clamped by switching the mask clamp mechanism 37 to the clamped state, thereby completing the replacement of the mask sheet 35. As a result, it is possible to shift to the printing operation of the substrate P of the next lot.

  When the mask sheet 35 is changed to a small size, the mask support base 36 is set at the advanced position. However, with respect to the substrate clamping mechanism 14, the joint piece 14b is removed as described above and the clamp piece 140 is removed. As a result, the clamp piece 140 does not interfere with the mask support 36 and does not interfere with the mask support table 36 even when the substrate P is overlapped with the mask sheet 35 in the printing operation of the next lot. Will be heavily loaded.

  As described above, in this screen printing apparatus, the interval between the two mask support bases 36 that support the mask sheet 35 is configured to be changeable by the sliding displacement, and accordingly, different size masks using the common mask support base 36. Since the sheet 35 can be supported and fixed, the mask sheets 35 having different sizes can be easily and quickly incorporated into the apparatus main body. Therefore, when the mask size is changed, it is necessary to remove and replace the mask support portion with respect to the apparatus main body. Can be performed efficiently.

  In addition, in this printing apparatus, the mask support base 36 is slid along the rail 42 by the drive of the servo motor 45. Therefore, the above-described interval changing operation of the mask support base 36 can be performed easily and quickly. Can be done.

  In addition, according to this printing apparatus, it is not necessary to prepare a plurality of mask support portions corresponding to the mask size in advance as in the conventional apparatus, so that there is an advantage that the printing operation can be carried out economically.

  In this apparatus, it is necessary that the length of the substrate P in the X-axis direction is smaller than the distance between the upstream conveyor 12A and the downstream conveyor 12C. There are no restrictions, and it may be short or long. This is because the clamp piece 140 is always positioned above the conveyors 12A to 12B in the positional relationship between the conveyors 12A, 12C and the clamp piece 140 in the vertical direction (Z-axis direction).

  The above-described printing apparatus is an example of a preferred embodiment of the screen printing apparatus according to the present invention, and the specific configuration thereof can be changed as appropriate without departing from the gist of the present invention. For example, the following configuration may be adopted.

  (1) In the above embodiment, both of the pair of mask support bases 36 provided in the apparatus main body are provided so as to be slidable along the rail 42 in the X-axis direction and are driven by the servo motor 45. However, only one of them may be slidably provided.

  (2) In the above embodiment, the mask support base 36 is configured to be set at any interval between the wide width and the narrow width. Of course, it can be set at an arbitrary interval between the wide width and the narrow width. You may comprise as follows. According to this configuration, since it becomes possible to cope with a larger number of mask sizes, the degree of freedom of usable mask sizes is improved.

  In this case, for example, table data in which the size of the mask sheet 35 and the interval between the mask support tables 36 are stored in advance is stored, and the mask support table 36 corresponds to the size according to the size input of the mask sheet 35. If the interval can be automatically changed, the replacement work of the mask sheet 35 accompanied by the change of the mask size can be performed more quickly.

  (3) In the above embodiment, the mask support base 36 is driven by a so-called ball screw mechanism using the servo motor 45, but the mechanism for driving the mask support base 36 is an actuator such as an air cylinder or an electromagnetic solenoid. Other mechanisms using may be used. In the case where a ball screw mechanism, a cylinder, or an electromagnetic solenoid is disposed, it is desirable to dispose the rail 42, but the mask support 36 may be held movably without the rail 42. In this case, the ball screw mechanism, the cylinder, and the electromagnetic solenoid also serve as the slide mechanism according to the present invention.

  (4) In the above embodiment, the mask support base 36 is driven using the servo motor 45. Of course, the mask support base 36 is manually operated by omitting the servo motor 45 and the ball screw shaft 44. You may comprise so that it may slide along the rail 42. FIG.

  In this case, for example, as shown in FIG. 8, a positioning hole 3 corresponding to the size of the mask sheet 35 is provided in the bracket 2 a, and the knock pin 4 is inserted across the mask support base 36 and the positioning hole 3. Thus, the mask support base 36 may be configured to be positioned in the Y-axis direction. In addition, the configuration in which the mask support base 36 is positioned by the knock pin 4 as described above is more accurate than the configuration in which the mask support base 36 is driven as in the above-described embodiment and the modified example (1). It is effective for positioning.

  (5) In the embodiment, the substrate clamping mechanism 14 is configured such that only one piece 14b is added to each side of the clamp piece main body 14a. However, another piece 14b is added to the piece 14b. The joint piece 14b may be configured so as to be continuously added. Specifically, for example, a knock hole corresponding to the knock pin 142 may be provided on the surface of the joint 14b opposite to the joint surface to the clamp piece main body 14a. According to this configuration, since the degree of freedom of the length of the clamp piece 140 is improved, this is effective when, for example, the interval between the mask support bases 36 is arbitrarily set as in the above modification (2).

It is a side view which shows an example of the screen printing apparatus which concerns on this invention. It is a front view which shows a screen printing apparatus. It is a perspective view which shows a screen printing apparatus (a squeegee unit abbreviation) (the state which has a mask support stand in a retreat position (wide state)). It is a perspective schematic diagram showing composition of a mask holding unit. It is a perspective exploded view which shows a main conveyor and a board | substrate clamp mechanism. It is a principal part perspective view of the main conveyor which shows the structure of a clamp piece. It is a perspective view which shows a screen printing apparatus (a squeegee unit abbreviation) (the state which has a mask support stand in an advance position (narrow state)). It is principal part sectional schematic drawing of the screen printing apparatus which shows the positioning structure of a mask support stand.

Explanation of symbols

2 Frame 13 Print stage 14 Substrate clamp mechanism 140 Clamp piece 14a Clamp piece body 14b Joint 20 4-axis unit 35 Mask sheet 36 Mask support 37 Mask clamp mechanism 42 Rail 45 Servo motor

Claims (1)

An apparatus main body including a pair of frames arranged in a first direction at a predetermined interval and extending in a second direction orthogonal to the first direction and a mask support portion provided in each of the frames, and a pair of opposing sides are the mask in the screen printing apparatus Ru and a mask sheet to be fixed to the apparatus main body while being supported respectively by the supporting portion,
A clamp mechanism that is provided on each of the mask support portions and detachably holds the mask sheet with respect to the mask support portions;
A slide driving means provided on at least one of the pair of frames to slide the mask support portion in the first direction;
The slide driving means is disposed at a position intermediate between the pair of rails that are fixed at positions spaced apart in the second direction of the frame and that support the mask support portion so as to be movable in the first direction. A screw shaft that extends in the first direction and is screwed into a nut member incorporated in the mask support portion, and a motor that rotationally drives the screw shaft, and the motor drives the screw shaft to rotate. Accordingly, the mask support portion is moved in the first direction, and the mask support portion is held at an arbitrary position or a specific position in the first direction by a static torque when the motor is stopped. Screen printing device.

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