JP2003094603A - Method for screen printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for screen printing enabling to print many kinds of pattern on a printing matter by screen printing with high accuracy and evenly by relatively simple way. SOLUTION: There is a preliminary printing process that provides at least two times of screen printing by driving a squeeze 5 at least at two kinds of squeeze moving speed. For the printing matter obtained at the preliminary printing process, the printing portion is divided into plural printing regions along the squeeze moving direction X, and at least one of those of a printing area, a printing volume and a printing thickness of each printing region is measured. From the obtained measurements, a relative formula for at least one of those of the moving speed of the squeeze 5, the printing area, the printing volume and the printing thickness of each printing region is secured. The moving speed of the squeeze 5 is calculated from the above relative formula in corresponding to the objective printing area, printing volume and printing thickness. The method for screen printing is provided by which the screen printing is performed according to the moving speed of the squeeze 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing method used for screen-printing a conductive paste or the like in the field of electronic parts, and more particularly to a screen printing method including a step of controlling a squeegee moving speed. Regarding

[0002]

2. Description of the Related Art Conventionally, when a ceramic electronic component such as a multilayer capacitor or a ceramic multilayer substrate is manufactured, a conductive paste is applied on a ceramic green sheet by screen printing to form internal electrodes. In this case, in order to improve mass productivity, usually, a large number of electrode patterns are printed at once by screen printing on a mother ceramic green sheet.

In the multilayer capacitor, if the area of the internal electrodes varies, the capacitance will vary. Therefore, when a large number of electrode patterns are screen-printed on the mother ceramic green sheet, high-precision printing is required. However, in reality, since it is difficult to print with high accuracy in the entire area on the mother ceramic green sheet, only the central portion of the printed area is used. Therefore, there is a problem that an extra material is required and the cost is high.

On the other hand, Japanese Laid-Open Patent Publication No. 2000-229400 discloses a screen printing apparatus capable of changing the film thickness of a print pattern by controlling the moving speed of a squeegee during screen printing, and a screen gap. Discloses a screen printing apparatus capable of controlling the film thickness of a print pattern. However,
According to this method, the print patterns having different film thicknesses were only formed by one screen printing, and the plurality of print patterns could not be printed uniformly and with high accuracy.

Further, in Japanese Unexamined Patent Publication No. 7-266539, in order to enable high-precision printing in a wide area on the printing medium, the moving speed of the squeegee is higher than that at the squeegee start side compared to the end side. A screen printing method for speeding up printing is disclosed. This method is effective when the printing pressure by the squeegee during screen printing is large. However, at present, when screen printing is performed with high accuracy, a method of reducing the printing pressure is adopted. On the contrary, when the printing pressure is lowered, the method described in this prior art may cause the print pattern to be blurred.

Japanese Laid-Open Patent Publication No. 6-336005 discloses a housing type squeegee device for improving printing accuracy. Here, by dividing the moving distance of the squeegee into a plurality of areas and controlling the moving speed of the squeegee, the rotation speed of the paste supply roll, and the printing pressure, optimum printing conditions are found, and the screen is printed under the optimum printing conditions. Printing is performed. However, the control factors are complicated,
There has been a problem that the preliminary printing process until finding the optimum printing conditions is complicated.

Japanese Unexamined Patent Publication No. 9-239956 discloses a screen printing method capable of printing a print pattern of an appropriate figure with high accuracy by appropriately changing the moving speed of a squeegee. . However, the method itself for determining the moving speed of the squeegee is not shown here.

[0008]

As described above, as described above,
Various methods have been proposed to improve the printing accuracy in screen printing, but no matter which method is used, it is possible to print a plurality of printing patterns with high accuracy in a relatively simple process. Was difficult.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to screen-print a paste as a plurality of printed figures, the steps for obtaining optimum conditions are simple, the yield is high, and It is an object of the present invention to provide a screen printing method capable of printing a printed figure with high accuracy.

[0010]

SUMMARY OF THE INVENTION The present invention is a screen printing method in which a screen is arranged on a material to be printed and a squeegee is moved to print the paste as a plurality of printing figures, and at least two squeegee moving speeds are provided. In the pre-printing step in which screen printing is performed at least twice with, and in the printed matter obtained in the pre-printing step, the printing portion is divided into a plurality of printing areas along the squeegee movement direction, and the printing area of each printing area, A measuring step of measuring at least one of a volume and a printing thickness; a step of obtaining a correlation expression between the squeegee moving speed in each of the printing areas and at least one of a printing area, a printing volume and a printing thickness; Squeegee in each print area corresponding to at least one of the target print area, print volume, and print thickness obtained from And a book printing step of performing screen printing according to the dynamic speed.

In a particular aspect of the present invention, the printing area is measured in the measuring step. In another specific aspect of the present invention, in the main printing step, at least one of a printing area, a printing volume and a printing thickness in each printing region of the printed matter is used.
Is measured, the correlation equation is corrected based on the obtained measurement value, the squeegee movement speed is obtained based on the corrected correlation equation, and the next printing is performed at the obtained squeegee movement speed.

[0012] In still another specific aspect of the present invention, at least one printed matter printed in the main printing step is
A stage for measuring at least one of the printing area, the printing volume and the printing thickness of one printing area, and the correction ratio of the squeegee moving speed in the printing area is obtained based on the obtained measurement value, and based on the correction ratio The stage for obtaining the next moving speed of the squeegee in all the printing areas and the stage for printing according to the obtained moving speed of the squeegee are repeated.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail by describing specific examples of the present invention.

FIG. 1 is a schematic block diagram showing a screen printing apparatus used in one embodiment of the present invention.
(A), (b) is the schematic plan view and schematic front view for explaining the screen printing method of one Example of this invention.

As shown in FIG. 2, the screen printing apparatus 1
Has a printing stage 2 on which a printing medium 3 made of a ceramic green sheet is placed. The printing object 3 is arranged on the printing stage 2, and the mask 4 shown by an imaginary line in FIG. 2A is placed on the printing object 3. A squeegee 5 is arranged above the mask 4. The squeegee 5 is moved in the arrow X direction in FIG.

That is, as shown in FIG. 2B, a mask 4 is placed on the substrate 3 to be printed, a conductive paste is applied on the mask 4, and the conductive paste 6 holds the squeegee 5. Printing is performed by moving.

In the present embodiment, a plurality of print figures 7 shown in a schematic plan view in FIG. 3 are printed on the printing medium. Each print figure 7 has a rectangular shape. At the time of printing, the squeegee is moved in the direction of the arrow X and a plurality of print figures 7 are printed.

Further, the screen printing apparatus shown in FIG. 1 is provided with a control device 11 and a printing area measuring device 12. The printing area measuring device 12 is configured to measure the area of the printed figure 7 in each printing area printed in the preliminary printing step.

A drive source 5a for driving the squeegee 5 is connected to the squeegee 5. The moving speed of the squeegee 5 can be changed by the drive source 5a. The drive source 5a is electrically connected to the control device 11, and the drive source 5a changes the moving speed of the squeegee 5 according to a command from the control device 11.

Further, the printing area measuring device 12 is a controller 1
1 is connected to the control device 11 and the measured printing area is
Is configured to be given to. The control device 11 is
The average area of the print figure in each given print area is calculated, and the correlation equation described later is obtained. Further, the control device 11
In the main printing step, the drive source 5a is provided with a command signal for moving the squeegee 5 in accordance with the target printing area and the squeegee running speed in each printing area according to the above correlation equation.

The screen printing method of this embodiment will be described below. In this embodiment, first, a preliminary printing step is performed prior to main printing. In the preprinting process, the controller 11 drives the drive source 5a, and screen printing is performed at least twice at at least two squeegee movement speeds. In this case, the squeegee is moved in the direction of the arrow X to print a plurality of print figures 7, but the area of each print figure 7 is not necessarily uniform. That is, the print area inevitably varies depending on the position of the print figure 7 along the arrow X direction.

In the present embodiment, the area of each printed figure of the printed matter obtained by performing the screen printing at least twice as described above is measured by the printing area measuring device 12,
This data is given to the control device 11. Control device 11
Divides the print portion into a plurality of print areas along the squeegee movement direction X. That is, the print portion is divided into a plurality of print areas indicated by A to D in FIG. And the control device 1
1 determines the average area of the printed pattern 7, that is, the electrode pattern in each of the printing areas A to D in each printed matter obtained in the preliminary printing step.

In this way, as shown in FIG. 4, the relationship between the position of the printed figure and the area of the printed figure at various squeegee movement speeds can be obtained. In FIG. 4, the printing speed is 2
0 mm / sec, 40 mm / sec, 60 mm / sec, 80 mm /
Results for seconds and 100 mm / sec are shown.

As is apparent from FIG. 4, the area of the printed figure changes depending on the position of the printed figure, regardless of the printing speed at which the squeegee is moved. The print area in FIG. 4 is the average value of the print areas of the plurality of print figures 7 in the area A of FIG. 3, for example. Further, in FIG. 3, only a plurality of print areas A to D are shown for ease of illustration, but as shown in FIG. 4, the print portion is divided into more print areas,
The average value of the print areas of the plurality of print figures in each print area is shown in FIG. 4 as the area of the print figure in the area.

In the present embodiment, as described above, in the printed matter obtained in the preliminary printing step, the printing area of the printed figure in each printing area is measured. After that, the control device 11
Calculates the correlation equation between the squeegee movement speed in each printing area and the printing area based on the results shown in FIG. For example, in the print area indicated by the arrow P in FIG. 4, the correlation expression (1) shown in FIG. 5 is obtained.

That is, the squeegee moving speeds in the print area indicated by the arrow P are 20, 40, 60, 80 and 1
The print area of the print figure in the print area P in the case of 00 mm / sec is shown in FIG. By approximating this result, the correlation equation (1) is obtained. This correlation equation (1)
Is represented by y = Mx- ^N (where M and N are constants obtained by approximation), where x is the moving speed of the squeegee and y is the average area of the printed figure.

The above correlation equation (1) is a correlation equation for the print area P. However, the control device 11 sets the correlation equation (1) for each print area divided along the squeegee movement direction. Similarly, the correlation equation is obtained. Therefore, when the print portion is divided into s print areas along the squeegee moving speed, for example, s correlation equations are obtained.

When the above correlation equation (1) is obtained, next,
The control device 11 obtains the squeegee movement speed in the printing region P based on the print area of the target print graphic 7 that has been input in advance. That is, the target print figure 7
The target squeegee moving speed x is obtained from y _t = Mx ^−N , where y _t is the average area of In this way, the squeegee movement speed to be set in each print area is obtained by substituting y = y _t in each correlation expression for each print area in the same manner as described above.

That is, as shown in FIG. 6, the squeegee movement speed that realizes the average print area y _t of the print figure 7 is obtained in each print area. Next, the control device 11 drives the drive source 5a according to the profile of the squeegee moving speed shown in FIG. 6, and the main printing is performed. Therefore, since the squeegee moving speed is controlled so as to have the profile shown in FIG. 5 and the screen printing is performed, the average area of the printed figure is y _t in each printing area. That is, the printing process is performed according to the profile of the squeegee movement speed shown in FIG. 6, and as shown in FIG. 7, the area of the printed figure can be made almost constant over the entire printing area.
The profile of the squeegee moving speed may not be stepwise as shown in FIG. 6A, but may be a gentle profile shown in FIG. 6B passing through the center point of each region.

In FIG. 4, the preprinting step was performed at five different squeegee moving speeds, so the number of printings in the preprinting step was 5. However, in the present invention, the above correlation equation (1) is obtained. As far as possible, screen printing with different squeegee movement speeds in the pre-printing process should be at least 2
It only needs to be held once. However, in order to control the printing area with higher accuracy, it is desirable that the number of times of printing in the preliminary printing step is 3 times or more, and more preferably 5 times or more.

As described above, in the screen printing method according to the present embodiment, only the above correlation equation in each printing area is obtained using the results of preliminary printing performed at different speeds.
Since it is possible to immediately set the squeegee movement speed in each print area that is the target area, it is possible to print each print figure easily and with high accuracy.

The printing area measuring device 12 is not particularly limited, and an image processing device, a device using an optical method such as a laser, or a mechanical length measuring machine can be used.

In the above embodiment, the average area of the printed figure 7 in each printing area was measured and the correlation expression (1) between the squeegee moving speed and the average area of the printed figure was obtained, but the printing area is not limited to the printing area. It is also possible to measure the printing volume and the printing thickness of the figure, obtain the correlation equation between these and the squeegee moving speed, and control the printing volume and the printing thickness instead of the printing area based on the correlation equation. That is, in the case of screen-printing a plurality of print figures on a printing medium, when the print volume or print thickness is important rather than the print area, the print volume or print thickness and the squeegee moving speed are determined as described above. By obtaining the correlation equation and controlling it in the same manner as in the above-described embodiment, it is possible to print a plurality of print figures with little variation in print volume and print thickness.

In some cases, the printing area, the printing volume, and the printing thickness are all measured, and the correlation equation between these values and the squeegee moving speed is obtained to control all of the printing area, printing volume, and printing thickness. Alternatively, screen printing may be performed. Further, in this case, when the printing area is more important than the printing volume and the printing thickness, weighting is applied to a plurality of correlation equations so that the value obtained by the correlation equation between the printing area and the squeegee moving speed is emphasized. Alternatively, the squeegee moving speed in each printing area in the main printing process may be obtained.

The method for measuring the print volume is not particularly limited, and a method using a laser, a light cutting method, or a method for obtaining a product obtained by measuring a print area and a print thickness can be used. . The method for measuring the printing thickness is not particularly limited, and a method using a laser, a reflection type radiation method, a transmission type radiation method, a method using infrared rays, a stylus type thickness measuring method, a contact type thickness measuring method, etc. may be used. You can

Further, preferably, in the main printing step, at least one of a printing area, a printing volume and a printing thickness in each printing area of the printed matter is measured, and the above correlation equation is corrected based on the obtained measured value. Then, the next squeegee moving speed may be calculated based on the corrected correlation formula, and the next screen printing may be performed based on the calculated next squeegee moving speed. In this case, in the main printing process, since the squeegee moving speed corresponding to the target printing area, printing volume and printing thickness is required with higher accuracy, each printed figure can be printed with even higher accuracy. it can.

In the main printing step, at least one of the printing area, the printing volume and the printing thickness of at least one printing area of the printed matter is measured, and the printing area is obtained based on the obtained measurement value. It is also possible to obtain the correction ratio of the squeegee movement speed in step 1 above and obtain the next squeegee movement speed in all the print areas, that is, in all the print areas including the print areas other than those for which the above measurement values were obtained. In this case, a more optimal squeegee moving speed is required in the main printing process, but it is not necessary to perform measurement in all printing areas when obtaining the correction ratio. Therefore, when the screen printing is repeated on a large number of printing materials, each printing figure can be printed with higher accuracy by a relatively simple process in the main printing process.

In the above embodiment, the case where the conductive paste is screen-printed on the ceramic green sheet has been described as an example, but the present invention is used for the method of screen-printing on the printing medium other than the ceramic green sheet. In addition to the conductive paste, other pastes such as a resistance paste can be used for screen printing.

[0039]

According to the present invention, in the preprinting step, it is sufficient to perform the preprinting at least twice. Based on the result of the preprinting step, the squeegee moving speed, the printing area, the printing volume, and the A correlation expression between at least one of the printing thickness and the squeegee moving speed is obtained, and based on the correlation expression, a squeegee moving speed corresponding to at least one of the target printing area, printing volume and printing thickness is obtained. The screen printing is performed according to the moving speed of the squeegee. Therefore, by performing a simple preliminary printing process, in the main printing process, printing can be performed with high accuracy so that the printing pattern of each printing region has a desired printing area, printing volume and / or printing thickness. it can.

When the printing area is measured in the above measuring step, the correlation equation between the squeegee moving speed and the printing area in each printing area is obtained. Therefore, in the main printing step, the printing figure of each printing area is calculated. It is possible to print with high accuracy so that the target printing area is obtained.

In the main printing step, at least one of the printing area, the printing volume and the printing thickness in each printing area of the printed matter is measured, and when the above correlation equation is corrected based on the obtained measurement value, the main printing is performed. When the steps are repeated, it is possible to print a print figure having a desired print area, print volume and / or print thickness on the object to be printed with higher accuracy.

In the main printing step, at least one of the printing area, the printing volume and the printing thickness of at least one printing area of the printed matter is measured, and the squeegee moving speed in the printing area is measured based on the measured value. When the correction ratio is calculated and the next squeegee movement speed of all the print areas is calculated based on the correction ratio, the printing accuracy in the main printing process can be increased by a relatively simple method.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a screen printing apparatus used in an embodiment of the present invention.

2A and 2B are a schematic plan view and a schematic front view for explaining a main part of a screen printing apparatus used in an embodiment of the present invention.

FIG. 3 is a schematic plan view for explaining a plurality of print areas.

FIG. 4 is a diagram showing an average area of a print figure in each print area in the case of different squeegee movement speeds, which is obtained in the preliminary printing step.

FIG. 5 is a diagram for explaining a correlation equation obtained based on measured values obtained in a preliminary printing process.

6A and 6B are views for explaining a squeegee moving speed in each print area obtained from a correlation equation in each print area.

FIG. 7 is a diagram showing a printing result in one example of the present invention, showing an average printing area of a printing figure in each printing region.

[Explanation of symbols]

1 ... Screen printing device 2 ... Printing stage 3 ... Printed material 4 ... Mask 5 ... Squeegee 5a ... Drive source 6 ... Conductive paste 11 ... Control device 12 ... Printing area measuring device

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Claims (4)

[Claims] 1. A screen printing method in which a screen is arranged on a material to be printed and a squeegee is moved to print the paste as a plurality of print patterns, wherein the screen printing is performed at least twice at at least two squeegee moving speeds. In the preprinting step and in the printed matter obtained in the preprinting step, the printing portion is divided into a plurality of printing areas along the squeegee moving direction, and at least one of the printing area, the printing volume and the printing thickness of each printing area. Measuring step of measuring one, a step of obtaining a correlation equation between the squeegee moving speed in each of the printing areas, and at least one of the printing area, the printing volume and the printing thickness, and the target printing obtained from the correlation equation. Screen according to the squeegee movement speed in each print area corresponding to at least one of area, print volume and print thickness. And a book printing step of performing printing, screen printing method. 2. The screen printing method according to claim 1, wherein the printing area is measured in the measuring step. 3. In the main printing step, at least one of a printing area, a printing volume and a printing thickness in each printing area of the printed matter is measured, and the correlation equation is corrected based on the obtained measurement value, 3. The screen printing method according to claim 1, wherein the squeegee moving speed is calculated based on the correlation equation, and the next printing is performed at the calculated squeegee moving speed. 4. A stage for measuring at least one of a printing area, a printing volume and a printing thickness of at least one printing area of a printed matter in the main printing step,
Based on the obtained measurement value, the correction ratio of the squeegee moving speed in the printing area is obtained, and the stage for obtaining the next squeegee moving speed of all the printing areas based on the correction ratio and the squeegee moving speed obtained 2. The printing stage and the printing stage are repeated.
Or the screen printing method according to 2.