JP2002316404A - Electrode pattern forming method and offset press using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode pattern forming method not generating a whisker flaw and transparence, and an offset press used therein. SOLUTION: In the electrode pattern forming method wherein build-up printing is applied to a substrate by an offset printing method using a conductive ink containing a conductive powder and an organic component, which is removable by baking, and the printed substrate is subsequently baked to form the electrode pattern with a film thickness of 2 μm or more, a surfacing roll for uniformizing the film thickness of the ink on a filling roll to prevent the filling undulation in the film thickness direction of the ink is provided to the filling roll of the offset press to perform printing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming an electrode pattern and an offset printing machine used for the method.

[0002]

2. Description of the Related Art Conventionally, it has been required that fine pattern formation of electrodes in an electronic circuit, an image display device, and the like can be performed with higher accuracy and at lower manufacturing cost.

Conventionally, as a method for forming a fine electrode pattern, a pattern is formed by a screen printing method or a photolithography method using a pattern forming paste containing conductive powder, and then fired to form an electrode pattern. There is a way. However, in the electrode pattern formation by the screen printing method, there is a limitation in printing accuracy due to the elongation of the mesh material constituting the screen printing plate, and a mesh formed in the formed pattern or a blur of the pattern occurs, and the electrode pattern is formed. There is a problem that edge accuracy is low. In addition, although the photolithography method can form a highly accurate electrode pattern, the manufacturing process is complicated, the material loss is large, and the reduction in manufacturing cost is limited.

For this reason, attempts have been made to reduce the cost of forming a fine electrode pattern by using an offset printing method which has a simple process and has high productivity. In this offset printing method, a conductive ink containing conductive powder is supplied to an intaglio or planographic printing plate, and the ink pattern on the printing plate is transferred onto a substrate via a blanket. After that, it is fired to decompose and volatilize the organic component, thereby forming an electrode pattern.

FIGS. 1 and 2 show an example of a conventional offset printing machine. FIG. 1 is a schematic plan view and FIG. 2 is a schematic side view.
The offset printing press 11 includes a base 12, a printing platen 13 and a printing plate 14 arranged at predetermined intervals on the base 12, and two printing plates laid in parallel on the base 12. And a print head 16 movable on the guide rails 15 by a moving mechanism (not shown).

The print head 16 includes a blanket roll 17 that can be moved up and down and a first inking roll group 1.
8 are provided. The first inking roll group 18 includes a filling roll 18a for supplying ink to the printing plate and a swing roll 18b. On the other hand, the base 12 is provided with a second inking roll group 19 and an ink blade 20 for storing the conductive ink. The second inking roll group 19 includes an ink ejection roll that ejects ink from the ink blade 20, a swinging roll that swings in the rotation direction of the roll, and the like.

In the offset printing press 11, a glass substrate 21 as a printing medium is placed on a printing platen 13, and a printing plate 22 is mounted on a printing plate 14. Then, the print head 16 first moves on the guide rails 15 and 15 toward the second inking roll group 19 and moves to a position where the first inking roll 18 faces the second inking roll group. . And at the position where both inking roll groups face each other,
The ink is supplied from the second inking roll group 19 to the filling roll 18 of the first inking roll group 18 of the print head 16.
a. Next, the print head 16 moves on the guide rails 15, 15 toward the printing plate 14, and the printing plate 22 is filled with ink from the filling roll 18 a. After that, the print head 16 moves on the guide rails 15 and 15 for a second time.
Then, the ink is supplied from the second inking roll group 19 to the filling roll 18a again. During this time, the blanket 17 is at an elevated position so as not to contact the printing plate 22.

Next, the print head 16 moves toward the printing platen 13 with the blanket roll 17 lowered to the printing position. The printing head 16 is connected to the printing plate 1
4, the ink on the image portion of the printing plate 22 is transferred to the blanket roll 17, and at the same time, the printing plate 22 is newly filled with the ink by the filling roll 18a. The print head 16 further moves toward the printing platen 13, and the ink is transferred from the blanket roll 17 to the glass substrate 21, which is the printing object placed on the printing platen 13. Thereafter, the print head 16 returns to the second inking roll 19.

[0009]

However, the above-described offset printing machine is used to perform thick printing on a glass substrate to a thickness of about 5 to 20 .mu.m by an offset printing method and then sintering to produce an electrode pattern of 2 to 10 .mu.m. The following problems occur when trying to form

First, cohesive failure occurs when the filling roll is filled with ink from the inking roll and when the ink of the blanket is received and transferred to the printing surface. As a result, a whisker-like defect 3 is generated in which the ink jumps out from the contour of the pattern 2 formed on the substrate 1. Even if an attempt is made to equalize the thickness of the ink film transferred to the printing surface so as to suppress the generation of this whisker-like defect, a conventional offset printing machine cannot achieve this thickness under the condition that thick printing is performed. Control is difficult.

Second, large ink swells occur in a printing area having a large area of 1 mm ² or more, and a missing due to poor reception / transfer occurs. Even if an attempt is made to equalize the film thickness of the ink transferred to the printing surface so as to suppress the occurrence of the undulation, the uniformity is not achieved under the condition that the conventional offset printing machine performs thick printing. Have difficulty.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming an electrode pattern free from whisker-like defects and no missing lines, and an offset printing machine used in the method.

[0013]

The invention according to claim 1 is for solving the above-mentioned problems relating to the method for forming an electrode pattern, and contains at least a conductive powder and an organic component which can be removed by firing. In a method of forming an electrode pattern having a film thickness of 2 μm or more on a substrate by baking after thick printing by an offset printing method using a conductive ink and offset printing, a filling roll of a printing machine is provided on a filling roll. It is characterized in that printing is performed by providing a facing roll for uniforming the ink film thickness and preventing swelling in the ink film thickness direction. According to this method, it is possible to reduce the unevenness of the thickness of the ink on the filling roll, thereby suppressing the occurrence of whisker-like defects and preventing unplugging.

In the method of forming an electrode pattern according to the present invention, at least one facing roll is provided for the filling roll of the printing press, so that the thickness of the ink on the filling roll can be made uniform.

In the method of forming an electrode pattern according to the present invention, the thickness of the ink on the filling roll is also made uniform by providing at least a facing roll on the filling roll of the printing press via a swinging roll. be able to.

According to a fourth aspect of the present invention, there is provided an offset printing press having a filling roll for supplying ink to a printing plate. It is characterized in that a surfacing roll for providing a uniform film thickness of the ink on the roll is provided.

In the printing press of the present invention, the filling roll has
At least one facing roll is provided.

Further, in the printing press of the present invention, an oscillating roll is provided for the filling roll, and at least one facing roll is provided for the oscillating roll for the oscillating roll.

According to the offset printing press of the present invention, the blanket can uniformly receive ink with an appropriate ink thickness and can be transferred from the blanket to the printing material, thereby suppressing the generation of whisker-like defects. It is possible to prevent unplugging.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 4 shows a print head 26 of an offset printing press used in the method of the present invention. The print head 26 includes a filling roll 28a.
At a, at least one surfacing roll 28b and a swing roll 28c are provided at intervals corresponding to the film thickness of the ink. In the example shown in FIG. 4, the facing rolls 28b are provided on both sides of the swing roll 28c.

The surfacing roll 28b is made of silicon, fluororesin, or the like, and functions to level the ink on the filling roll to a uniform thickness. This surface roll 28
By b, the ink on the filling roll is first made uniform in thickness. Then, the plate is filled while maintaining the uniformity of the thickness. Further, the ink filled while maintaining the uniform thickness of the plate is received by a blanket, and further transferred from the blanket onto a glass substrate as a printing medium.

As a result, the thickness of the ink is suppressed to an appropriate range or less, so that the occurrence of a whisker-like defect due to the excessive thickness of the ink is prevented. In addition, large swells of ink filling are prevented from occurring in a printing area having a large area of 1 mm ² or more, and a dropout due to poor reception / transfer is prevented.

FIG. 5 shows another embodiment of the print head 26 provided in the offset printing machine used in the method of the present invention. In this embodiment, a facing roll 28b is provided for a filling roll 28a via a swing roll 28c.

The printing press used in the method of the present invention is the same as that of the conventional printing apparatus except that the configuration of the print head 26 is different as described above.

Example 1 A conductive ink having the following composition was prepared. Composition of conductive ink・ Silver powder 77.5 parts by weight (tap density 4.5 g / cm ² , surface area 2.4 m ² , average particle size 0.3 μm) ・ Glass frit (Bi ₂ O ₃ glass) 2.5 parts by weight (coefficient of thermal expansion: 81 × 10 ⁻⁷ / ° C., glass transition temperature: 460 ° C., softening point: 525 ° C., average particle size: 0.9 μm) ・ Resin: 20 parts by weight (allyl ether-maleic anhydride-styrene) Polymer)

Next, an offset printing machine equipped with a print head shown in FIG. 3 was used. A blanket (silicon rubber-based blanket) was mounted on this printing machine, and a glass substrate (soda glass, soda glass, 350mm
(× 450 mm, thickness 2.1 mm) was printed under the following printing conditions, and then fired at 580 ° C. for 10 minutes to form an electrode pattern.

Printing conditions Printing speed: 500 mm / sec Printing pressure: 0.1 mm Number of printings: 2 times Printing plate used: Waterless plate manufactured by Toray Industries, Inc. (DG-2), (image area width 50 μm)

As a result, the film thickness was 8 μm and the undulation of the film thickness was 1
A μm electrode pattern was obtained. No beard-like defect or missing was found in this electrode pattern.

Example 2 An offset printing press having a print head shown in FIG. 4 was used in the same manner as in Example 1. As a result, similarly, the film thickness was 8 μm, and the undulation of the film thickness was 1 μm.
Was obtained. No beard-like defect or missing was found in this electrode pattern.

[0031]

As described in detail above, thick printing is performed by offset printing using a conductive ink containing at least a conductive powder and an organic component which can be removed by baking, followed by baking to form a film of 2 μm or more. In the method of forming an electrode pattern having a thick electrode pattern on a substrate, a method for forming a uniform thickness of the ink on the filling roll with respect to the filling roll of the printing press to prevent swelling of the ink in the thickness direction of the ink. By performing printing by providing a surface roll, unevenness in the thickness of the ink on the filling roll can be reduced, thereby suppressing the occurrence of whisker-like defects and preventing plain dropout.

Further, the offset printing machine of the present invention is provided with a filling roll for supplying the ink to the printing plate, and a facing roll for making the film thickness of the ink on the filling roll uniform with respect to the filling roll. Is provided, so that the thickness of the ink is suppressed to an appropriate range or less, so that the occurrence of a whisker-like defect due to the excessive thickness of the ink is prevented. In addition, large swells of ink filling are prevented from occurring in a printing area having a large area of 1 mm ² or more, and a dropout due to poor reception / transfer is prevented.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of an example of a conventional offset printing press.

FIG. 2 is a schematic side view of the offset printing press shown in FIG.

3A and 3B show the occurrence of whisker-like defects. FIG. 3A is a cross-sectional view, and FIG.

FIG. 4 is a schematic side view of a print head included in the offset printing press of the present invention.

FIG. 5 is a schematic side view of another embodiment of the print head provided in the offset printing press of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 offset printing machine 12 base 13 printing platen 14 printing plate 15 guide rail 16 printing head 17 blanket 18 first inking roll group 18a filling roll 18b swinging roll 19 second inking roll group 20 ink blade 21 Glass substrate 22 Printing plate 26 Print head included in offset printing machine of the present invention 28a Filling roll 28b Surface roll 28c Swinging roll

Claims (6)

[Claims] An electrode pattern having a thickness of 2 μm or more is printed on a substrate by thick printing by offset printing using a conductive ink containing at least a conductive powder and an organic component that can be removed by firing. In the method of forming an electrode pattern to be formed, printing is performed by providing a facing roll for making the ink film thickness on the filling roll uniform with respect to the filling roll of the printing machine and preventing filling swell in the ink film thickness direction. A method for forming an electrode pattern. 2. The method for forming an electrode pattern according to claim 1, wherein at least one facing roll is provided for the filling roll of the printing press, and the thickness of the ink on the filling roll is made uniform. 3. The printing press according to claim 1, wherein at least a facing roll is provided via a swinging roll with respect to a filling roll of the printing press to make the thickness of the ink on the filling roll uniform.
3. The method for forming an electrode pattern according to item 1. 4. A filling roll for supplying ink to a printing plate, and a facing roll for making the film thickness of the ink on the filling roll uniform is provided for the filling roll. Offset printing press. 5. The offset printing press according to claim 4, wherein the filling roll is provided with at least one facing roll. 6. The oscillating roll is provided for the filling roll, and at least one facing roller is provided for the oscillating roll for the oscillating roll. The offset printing press according to 1.