JP2012125940A - Screen printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen printer preventing inclination of support pins and achieving improvement of printing accuracy.SOLUTION: The screen printer includes a base plate support table having the plurality of erected support pins supporting a carried substrate. Printing is performed by pressing the substrate supported by the support pins against a chute carrying the substrate. A low friction resistance part is arranged at a tip of the support pin brought into contact with the substrate.

Description

  The present invention relates to a screen printer that applies a coating material onto a substrate supported by support pins, and more particularly to a screen printer that can improve printing accuracy.

  As shown in FIG. 7, a printed circuit board (hereinafter simply referred to as a substrate) P is pressed against and fixed to a chute 19A that constitutes a conveyance path for conveying the substrate, and the coating material applied on the screen is squeegee moved to the substrate. There is a screen printer that prints. An example of this type of screen printing machine is Patent Document 1.

JP 2009-101707 A

  However, in the conventional method, when the substrate moves in the horizontal direction with the tip of the support pin in contact with the bottom surface of the substrate, the unevenness on the bottom surface of the substrate P is supported by the frictional resistance at the bottom surface of the substrate and the tip of the support pin. There is a risk that the support pin may be inclined although it is caught by the tip of the pin. In this way, when printing is performed with a finer and finer pitch pattern while the support pins are slightly inclined, the inclined support pins cause protrusions and recesses on the substrate. In such a state, the printing accuracy may not be improved due to a slight displacement of the substrate due to the movement of the squeegee.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a screen printing machine that can prevent the inclination of the support pins and improve the printing accuracy.

In order to achieve the above object, the present invention has at least the following features.
The present invention provides a substrate support table that erects a support pin that supports a substrate that has been transported, and a screen printer that presses the substrate supported by the support pin against the transport chute for printing. The pin is characterized by having a low friction resistance portion at a tip portion that contacts the substrate.

The second feature of the present invention is that the low frictional resistance portion is a rotating member rotatably provided at the tip portion.
The third feature of the present invention is that the rotating member is a steel ball or a roller that rotates in a pressing direction of the substrate.

The fourth feature of the present invention is that the low frictional resistance portion is a low frictional resistance material having a smaller frictional resistance than stainless steel.
Furthermore, the present invention is characterized in that the low friction resistance material is a fluororesin.

Further, the present invention is characterized in that the support pin includes a compression material that supports the low frictional resistance portion in the direction of gravity.
Furthermore, the present invention is characterized in that the compression member is a spring or an elastic rubber.

  The eighth feature of the present invention is that the pressing direction coincides with the sliding direction on the screen of the squeegee to be printed.

  ADVANTAGE OF THE INVENTION According to this invention, the screen printer which can prevent the inclination of a support pin and can improve printing accuracy can be provided.

It is a front view of the principal part of the screen printer which is embodiment of this invention. It is a right view of the principal part of the screen printer shown in FIG. It is a figure which shows the structure of the positioning mechanism which positions a board | substrate in a predetermined position in order to print among board | substrate support apparatuses. It is a figure which shows the processing flow which prints the board | substrate in the screen printer which is embodiment of this invention. It is a figure which shows the state which pressed the board | substrate P against the fixed chute side. It is a figure which shows each Example of the support pin in the screen printer which is embodiment. It is a figure which shows the structure of the positioning mechanism which has the conventional support pin.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a main part of a screen printer according to an embodiment of the present invention, and FIG. 2 is a right side view of the main part of the screen printer shown in FIG.
As shown in FIG. 1, the screen printing machine 1 includes a substrate support device 12 installed on a base 11, screen support means 13 disposed above the substrate support device 12, and a substrate support device 12. A first image pickup means 14 for picking up an image of a substrate recognition mark (not shown) placed between the screen support means 13 and supported on the diagonal line of the substrate P supported by the substrate support device 12, and the screen support means 13; The second image pickup means 15 for picking up an image of a screen recognition mark attached to the screen S, which is arranged above the screen S and supported by the screen support means 13, and a pair of print heads (pitch 16A, 16B ( 2), a supply conveyor 17 for supplying the substrate P onto the substrate support device 12, a discharge conveyor 18 for discharging the substrate P from the substrate support device 12, and a first Displaying an image captured by the beauty second imaging means 14, 15 and a monitor (not shown).

  The substrate support device 12 has a first moving mechanism 21 for moving in the X-axis direction (see FIG. 1) extending in the horizontal direction, and a rotation provided on the first moving mechanism 21 for rotating in a horizontal plane. A mechanism 22, a second moving mechanism 23 provided on the rotating mechanism 22 for moving in the direction of the Z-axis extending in the vertical direction, a plurality of support pins provided on the second moving mechanism 23, which will be described later, and these And a pair of fixed chutes 19A and movable chutes 19B (see FIG. 3 to be described later) that are provided above the substrate support table 24 and convey the printed circuit board P in the X-axis direction. A transport chute.

  The screen support means 13 includes a screen support frame 25 that supports the peripheral edge of the lower surface of the screen S, cylinders 26 and 26 that are disposed above the screen support frame 25 and press the screen S against the screen support frame 25, and horizontal And a moving mechanism 27 for moving in the direction of the Y axis extending in the direction.

  The first imaging means 14 includes a substrate recognition camera 28, a moving mechanism 29 that moves the substrate recognition camera 28 in the X-axis and Y-axis directions, and an illumination device that irradiates the substrate P on the substrate support table 12 with light. (Not shown). The second imaging means 15 includes a screen recognition camera 31, a moving mechanism 32 that moves the camera 31 in the X-axis direction, and an illumination device that irradiates light onto the substrate P on the substrate support table 12 (not shown). The camera 31 is moved in the Y-axis direction by the moving mechanism 34 of the print heads 16A and 16B.

  As shown in FIG. 2, the print heads 16A and 16B are arranged at intervals in the Y-axis direction, and squeegees 33A and 33B are respectively attached to the lower ends thereof, and are moved by the moving mechanism 34 (see FIG. 1). At the same time, it moves in the Y-axis direction and moves individually in the Z-axis direction by the vertical movement mechanisms 35A and 35B. When the print heads 16A and 16B move to the left in FIG. 2, the right print head 16A descends and the squeegee 33A slides on the screen S and moves to the right in FIG. The left print head 16B descends and the squeegee 33B slides on the screen S. Therefore, two printing processes are performed by one reciprocating movement of the print heads 16A and 16B.

  FIG. 3 is a diagram showing a configuration of a positioning mechanism 60 that positions the substrate P at a predetermined position for printing in the substrate support apparatus 12 described above. The positioning mechanism 60 includes a movable chute 19B having a fixed chute 19A for positioning the substrate P to a printable state and a third moving mechanism (pressing mechanism) 50 for horizontally pressing the substrate P toward the fixed chute 19A. The plurality of support pins 40 that support the substrate P during printing, the substrate support table 24 that erects the support pins 40, and the second moving mechanism 23 that raises the substrate support table 24 to a printing position.

The pressing mechanism 50 includes a pressing bar 51 that presses the substrate P against the fixed chute 19A, a sliding body 52 that is fixed to the pressing bar 51, a guide rail 53 that guides the sliding body 52 so as not to rotate, and a sliding body 52. Has a cylinder 55 that moves the cylinder lot 54 fixed in the left-right (Y) direction. In addition, 56 is a stopper that prevents excessive pressing, and 57 and 58 are connection nozzles for supplying and discharging air.
The fixed chute 19A and the movable chute 19B are each provided with a motor-driven pulley 61, and the conveyor belt 62 is moved by the rotation of the pulley 61 so that the substrate P is conveyed.

FIG. 4 shows a processing flow in which the substrate P is fixed without being shaken and printed even when the squeegees 33A and 33B shown in FIG.
First, the substrate P is transported to a desired position on the substrate support table 24 and stopped (Step 1). Thereafter, the first image pickup unit 14 picks up an image of a substrate recognition mark (not shown) attached to the position on the diagonal line of the substrate P and performs alignment (Step 2). Next, the substrate support table 24 is raised, the support pins 40 are brought into contact with the lower surface of the substrate P, and the substrate P is pressed against the fixed chute 19A as shown in FIG. 5 by the pressing mechanism 50 (Step 3).

  Next, with the substrate P pressed, the substrate P is raised to a position where the upper surface of the fixed chute 19A and the upper surface of the movable chute 19B and the upper surface of the substrate P are at the same height (Step 4). Then, the squeegees 33A and 33B are slid on the screen S and printed on the substrate P (Step 5). The sliding direction is matched with the pressing direction of the substrate. Stable pressing can be realized by matching. When the printing is completed, the pressing is released, the substrate P is lowered and placed on the transport belt 62 (Step 6), and is unloaded from the screen printer 1 (Step 7). A predetermined number of processes are performed from Step 1 to Step 7 (Step 8).

  Here, Step 4 is a problem. As already described with reference to FIG. 7, in the conventional method, when the substrate moves in the horizontal direction with the tip of the support pin hitting the bottom surface of the substrate, or by the frictional resistance between the bottom surface of the substrate and the tip of the support pin, or The unevenness on the lower surface of the substrate P is caught on the tip of the support pin, and the support pin may be slightly inclined. In this way, when printing is performed with a finer and finer pitch pattern while the support pins are slightly inclined, the inclined support pins cause protrusions and recesses on the substrate. In such a state, the printing accuracy may not be improved due to a slight displacement of the substrate due to the movement of the squeegee.

  Therefore, in the present invention, a low friction resistance portion is provided at the tip of the support pin 40 that contacts the substrate P. In the present embodiment shown in FIG. 3, a rotating member that is a steel ball 41 is provided as a low frictional resistance portion at the tip portion of the support pin 40 that contacts the substrate P. A magnet 45 </ b> A is provided as a fixing member on the base side of the support pin for fixing to the substrate support table 24. By providing the steel ball 41 at the tip portion, the frictional resistance is reduced, the tip of the support pin is not caught by the irregularities on the lower surface of the substrate P, the tilt of the support pin 40 can be prevented, and the substrate P is smoothly placed on the fixed chute 19A. Can be pressed against.

In some cases, dust or the like is caught at the base of the support pin, and the support pin 40 is slightly inclined. Even in such a case, the substrate P can be smoothly pressed against the fixed chute 19A without further increasing the inclination of the support pin 40.
As a result, the inclination of the substrate is suppressed to the minimum, that is, the convex portions and the concave portions generated on the substrate are suppressed to the minimum, the substrate P can be firmly fixed, and printing can be performed with high accuracy.

  FIG. 6 is a view showing another embodiment of the support pin 40 including the low frictional resistance portion. The support pin 40A shown in FIG. 6 (a) further pushes up the steel ball 41 from below to the support pin 40 shown in FIG. 6 (a), in other words, acts as a compression material 42 that supports the steel ball 41 in the direction of gravity. A spring 42A is provided (Example A). The spring 42A can absorb and reduce the impact of the support pins, which are raised as the second moving mechanism 23 is raised, coming into contact with the substrate P by the spring 42A. As a result, in addition to the effects of the support pins 40 shown in FIG. 3, scratches and indentations on the substrate P can be prevented, and the product quality of the substrate P can be improved.

  A support pin 40B shown in FIG. 6B is provided with a roller 41B that rotates in the moving direction as a rotating member instead of the spring 42 in the embodiment A (embodiment B). FIG. 6B shows a view seen from a direction perpendicular to the pressing direction of the substrate. In Example B, the same effect as Example A can be produced.

  The support pin 40C shown in FIG. 6 (c) is more frictional than stainless steel forming a conventional support pin at the tip of the support pin 40B as a low friction resistance portion instead of the rotating member shown in the embodiments A and B. A low friction resistance material portion 43 formed of a low friction resistance material having a low resistance, for example, a fluororesin portion 43C formed of a fluororesin is provided (Example C). Example C has a simple structure and is suitable when there is no or little unevenness on the lower surface of the substrate P.

  The support pin 40D shown in FIG. 6 (d) is provided with an elastic rubber 42D instead of the spring 42A shown in FIG. 3 and FIGS. 6 (a) to 6 (b) as the compression material 42, and as a fixing member in FIG. A convex portion 45D is provided at the root instead of the magnet 45 shown in FIGS. 6A to 6C (Example D). In Example D, the same effects as in Example A and Example B can be obtained.

According to the present embodiment described above, the frictional resistance is reduced, and even if there is unevenness on the lower surface of the substrate P, the substrate P can be smoothly pressed against the fixed chute 19A without being caught on the tip of the support pin. The inclination or further inclination of the support pin 40 can be prevented.
As a result, the printing accuracy on the substrate P can be ensured, or the product quality can be improved.

1: Screen printer 12: Substrate support device 13: Screen support means 16A, 16B: Print head 19A: Fixed chute 19B: Movable chute 21: First moving mechanism 22: Rotating mechanism 23: Second moving mechanism 24: Substrate supporting table 33A, 33B: Squeegee 40, 40A, 40B, 40C: Support pin 41: Steel ball 41B: Roller 42: Compression material 42A: Spring 42D: Elastic rubber 43: Low friction resistance material portion 43C: Fluorine resin portion 50: Pushing mechanism (Third moving mechanism)
51: Pushing bar 51 55: Cylinder 60: Positioning mechanism 61: Pulley 62: Conveying belt P: Printed circuit board (substrate).

Claims (8)

In a substrate support table that erects a support pin that supports a substrate that has been transported, and a screen printing machine that presses the substrate supported by the support pin against the transport chute for printing,
The screen printing machine according to claim 1, wherein the support pin has a low friction resistance portion at a tip portion in contact with the substrate.   The screen printing machine according to claim 1, wherein the low frictional resistance portion is a rotating member rotatably provided at the tip portion.   The screen printing machine according to claim 2, wherein the rotating member is a steel ball or a roller that rotates in a pressing direction of the substrate.   2. The screen printing machine according to claim 1, wherein the low friction resistance portion is a low friction resistance material having a friction resistance smaller than that of stainless steel.   The screen printing machine according to claim 4, wherein the low friction resistance material is a fluororesin.   5. The screen printing machine according to claim 1, wherein the support pin includes a compression member that supports the low frictional resistance portion in a direction of gravity.   The screen printing machine according to claim 7, wherein the compression member is a spring or an elastic rubber.   8. The screen printing machine according to claim 1, wherein the pressing direction coincides with a sliding direction on the screen of the squeegee to be printed.

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