JPH0123317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing method that uses a pattern shape suitable for thick film printing, such as screen printing and intaglio (gravure) offset printing, in which the ink film thickness is large. BACKGROUND ART Conventionally, electrode wiring for various display elements, electric circuit boards, etc. has often been formed by a thick film printing method known in the electronic parts industry. As a known thick film printing method, screen printing is widely used, but recently an intaglio (gravure) offset printing method has been developed. Both are printing methods that can print on hard materials with a large printing ink film thickness as a printing means, and all have a film thickness of 5 μm or more at the time of printing. When printing electrode wiring, resistors, fluorescent materials, magnetic materials, dielectric materials, etc. for display elements and electric circuit boards in the electronics field using these printing methods, the line width must be small; It is generally required that the positioning device itself has small variations and that the positional accuracy is accurate.
Screen printing can meet such demands.
Line widths of 150 μm or less are said to be difficult to produce stably on normal printing production lines. Recently, as the miniaturization of electronic components has been promoted, these thick film printed patterns have also become denser, and thin wires of 50 μm to 100 μm are now required for electrode wiring. In this case, intaglio (gravure) offset printing, which can handle finer lines than screen printing, is seen as more promising. In any of the above cases, it is required that the printed line width be uniform, that the positional accuracy be accurate, and that the film thickness be greater than necessary and uniform. This film thickness varies slightly depending on the target, but in the area of thick film printing for electronics parts, the film thickness is 5 μm or more and the average is about 7 to 15 μm. After treatment, it has sufficient electrical conductivity or, conversely, insulating properties. Even a film thickness of this level may be reduced to 4 to 10 μm due to high-temperature firing, etc., and there are many printing objects that require a large film thickness during printing in thick film printing. Therefore, in these thick film printing, thin lines of around 100 μm are used (in this case, the spacing is usually designed to be around 200 μm).
It is desirable to print the entire pattern with a film thickness of 5 μm or more, with line width and film thickness as uniform as possible. This means conductive or insulating, dielectric,
In addition to patterning magnetic and resistive materials,
This also applies to fluorescent materials, etching resists, spacer pastes, etc.

For such printing objects, with conventional printing methods, lines or pattern edges that are aligned with the printing direction can be reproduced relatively neatly and even with fine lines, but when printing in a direction perpendicular to the printing direction, It was difficult to accurately reproduce lines with the same orientation. The printing direction here refers to the inking and squeezing (printing) direction in screen printing, and the inking, doctoring direction, and plate or offset (transfer) direction in intaglio (gravure) offset printing. body) indicates the direction in which the print transfer moves and rotates. However, when the arrangement is such that the inking/doctoring direction and the transfer/transfer rotation direction are perpendicular to each other, the transfer/transfer rotation direction is indicated. During printing, the ink paste, which is pressurized both on the plate and on the substrate, tends to deform and move under external forces such as a squeegee doctor and printing pressure that act along the printing direction. In this case, for lines or pattern edges along the printing direction, the deformation or movement of the ink paste will be swayed and absorbed within the pattern, but for lines or pattern edges that are perpendicular to the printing direction, the ink paste that should rise up will collapse. Accurate printing is difficult because the line may protrude outside the pattern and short-circuit to an adjacent line, or conversely it may be interrupted, or the line may be distorted even if the line itself does not change. In addition, the ink used must not be hard such as intaglio ink or lithographic offset ink, but must be a relatively soft ink paste of 1000 ise or less (Bruckfield viscometer HBT-SC4-14 10 rpm), and thick film printing. Ink paste has a very high solids composition compared to normal ink, including more than 50% (by weight) of metal or inorganic solids, so it is a very crumbly, sand-like paste that is soft and easily crumbles. thing. Furthermore, since most printing materials are glass, ceramic (including green sheets), enamel substrates, and plastic films that do not absorb or embed ink, the ink paste is more likely to crumble during printing.

Pattern stains (or slurs) due to these ink collapses and fluctuations increase in size as the thickness of the printed ink paste increases, and serious defects such as short circuits occur where patterns or lines are closely spaced. Thick film printing covered by this law:
With a line width of 300 μm and a line width (interval of 300 μm) or more, even if the film thickness is quite large, serious defects such as short circuits will not occur, and the width of contamination will not be noticeable compared to the line width. Furthermore, if the line width is 300 μm, the pattern will not be interrupted. If the line width is less than 300 μm (the spacing is also 300 μm), there are many opportunities for the above-mentioned serious defect to occur. Such stains are particularly likely to occur in the case of an intaglio (gravure) offset method having a soft transfer body. Furthermore, when the shape of the transfer body has a cylindrical rotation type structure, the occurrence rate is high, and there is a large difference in the shape of the pattern when the direction is the same as the printing rotation direction and when the direction is perpendicular to the printing rotation direction.

The present invention provides a means for solving the above-mentioned problems, and by partially deforming or changing the direction of the printed pattern with respect to the printing method of the printing machine, it is possible to create a thick film that does not cause any problems in practice. This allows printing.

In other words, in a printing method that produces a large film thickness, the present invention is designed to adjust the printing direction and plate so that the inclination angle of the line or pattern edge of the pattern original to be printed is 75 degrees or less with respect to the printing direction. In a thick film printing method characterized by printing by setting a relative positional relationship and a printing method in which the printed film thickness is large, the pattern original image to be printed is a line that is perpendicular to the pattern parallel to the printing direction. or a pattern including a pattern edge, the direction of the line or pattern edge perpendicular to the printing direction is tilted at an angle of 15 degrees or more to the printing direction, or the direction of the pattern edge is corrected to a curve, and the plate is made and printed. This is a thick film printing method characterized by the following.

Hereinafter, the present invention will be explained in more detail using the drawings. FIG. 1a shows the original of the pattern to be printed, and FIG. 1b shows the printed reproduction pattern stained by conventional gravure offset printing. In order to prevent these stains, in the present invention, the second
It has been found that serious defects do not occur if the inclination angle θ of the line or pattern edge with respect to the printing direction is within a range of 75° as shown in Figure a. (When the angle θ=0, the line or pattern edge is parallel to the printing direction.) Therefore, it is possible to print any pattern that has a pattern edge line at an angle within the shaded range shown in FIG. 2b. In such a case, it may be possible to achieve the objective by setting the printing direction and the relative positional relationship between the printing plates in this way without changing the pattern configuration itself. However, there is a risk that even lines that are originally parallel to the printing method may become tilted, making printing difficult. In that case, it is effective to create a pattern in which only the vertical (right-angled) portion of the pattern is tilted as shown in FIG. FIG. 3a shows the original pattern and FIG. 3b shows the pattern according to the invention. Originally, the parallel lines 1 or the connecting lines 2 connecting the terminal parts 3 as shown in a are usually connected perpendicularly (at right angles) in view of the pattern drawing technique and the saving of materials, but the present invention is suitable for thick film printing. The following pattern configuration is effective.

Furthermore, in carrying out the present invention, the inventor found that in addition to the above-mentioned method of connecting bent lines and corners of patterns with diagonal lines, a method of connecting with continuous curved lines is also very effective in preventing stains. Ta.
It is effective to make not only right-angled corners but also curved lines that connect bent lines.
An example of this is shown in FIG. 3c. With this pattern, most lines or edges of the pattern were printed smoothly without strain and without breaking the mounds of thick ink paste. As shown in FIG. 4, it is of course possible to combine and arrange several pattern shapes according to the above-described invention to produce printed matter with as little dirt as possible.

According to the present invention, stains are reduced and good thick film printing becomes possible. In particular, if a pattern that repeats at the same interval (for example, a line pattern) is perpendicular to the printing direction, there may be a break in that part.
Serious defects such as short circuits were likely to occur, but this has been significantly improved by the present invention. These serious defects are very finely spaced and thin lines (line width less than 300μm,
Plasma display panels, fluorescent display tubes, thermal printer heads, printed circuit boards, hybrid circuit boards, etc., in which electrodes and resistive elements are formed in repeated rows (with the same spacing), and fluorescent elements in color television picture tubes. This is fatal for creating a light surface, and the effects of the present invention are significant.

Furthermore, among thick film printing, the present invention is suitable for the intaglio (gravure) offset method, which is inherently prone to double-like stains, in which printing is performed after transferring the material to a soft transfer material, unlike direct printing such as screen printing. more effective.

Furthermore, in the printed matter produced according to the present invention, the number of pattern edges or lines in the perpendicular direction is reduced as much as possible, so that the blades of the doctor and squeegee, which are arranged perpendicular to the printing direction, fall into the recesses of the plate. This enables smooth squeegeeing and doctoring without damaging the ink or scraping off more ink in the recesses than necessary, making thick film printing of uniform thickness possible.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIGS. 1a and 1b show printed reproduction patterns obtained by the conventional method, and FIGS. 2a and 2b illustrate the first method of the present invention. Figures 3a, 3b, and 4c and 4 respectively show illustrations of the second method. θ...Angle, 1...Parallel line, 2...Connection line, 3
...Terminal section.

Claims (1)

[Claims] 1. In a printing method that prints a large film thickness,
Thick film printing characterized by printing by setting the relative positional relationship between the printing direction and the plate so that the inclination angle of the line or pattern edge of the pattern original to be printed is 75 degrees or less with respect to the printing direction. Law. 2 In printing methods that print a large film thickness,
When the original pattern to be printed is composed of a pattern parallel to the printing direction and a pattern including lines or pattern edges perpendicular to the printing direction, the direction of the lines or pattern edges perpendicular to the printing direction is set relative to the printing direction. A thick film printing method that is characterized by printing by tilting the plate at an angle of 15° or more or by modifying it into a curved line. 3 The pattern original to be printed is the pattern width
The thick film printing method according to claim 1, which includes patterns of 300 μm or less or a pattern interval of 300 μm or less. 4 The pattern original to be printed is the pattern width.
The thick film printing method according to claim 2, which includes patterns of 300 μm or less or a pattern interval of 300 μm or less. 5. The thick film printing method according to claim 1, which is printed by an intaglio (gravure) offset printing method. 6. The thick film printing method according to claim 2, which is printed by an intaglio (gravure) offset printing method.