JPH04320855A - Printing head substrate and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide the manufacture of a print head substrate by a low-cost printing process and a low-cost print head substrate having high performance manufactured by the printing process regarding a print head, a particularly the print head substrate using a discrete hating resistor. CONSTITUTION:Discrete heating resistors 3 with arcuate projecting sections, in which the ratio of length to width is three of more and the shapes of cross sections rectangular in the direction that currents are made to flow are two or more, discrete electrodes 1 and a common electrode 2 are formed through an intaglio offset printing method, in which ink in transferred onto a rubber roller having mold-release characteristics such as a silicone rubber roller once from an intaglio printing such as glass integlio printing and printing is conducted onto a substrate. Accordingly, heat generation in the discrete heating resistors 3 can be further made uniform, thus acquiring a low-cost printing head substrate enabling printing having high quality.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head substrate for printing devices used in facsimiles, printers, etc., and more particularly to a print head substrate such as a thermal head using a heating resistor and a method for manufacturing the same.

0002

2. Description of the Related Art In recent years, with the spread of facsimiles, the demand for print heads, especially thermal heads, has been increasing. Therefore, there is a strong demand for lower costs and higher performance of print head substrates.

[0003] A conventional print head substrate and a method of manufacturing the conventional print head substrate will be described below. (FIG. 6) is a configuration diagram of a conventional print head board. The print head substrate shown in FIG. 6 is a print head substrate for a thin film thermal head, and generally has individual heating resistors and has high print quality. In FIG. 6, 1 is an individual electrode, 2 is a common electrode, 3 is an individual heating resistor, 4 is a glaze layer, 5 is an alumina substrate, and 6 is a protective layer. Hereinafter, reference numerals in the drawings indicate the same names. The thermal head is a device that generates heat by passing an electric current through individual heating resistors 3 between electrodes, and uses this heat to color thermal paper or melt ink on an ink ribbon to perform printing. Further, FIG. 7 shows a diagram of a conventional print head substrate manufacturing process, which is a thin film thermal head manufacturing process, as an example of a conventional print head substrate manufacturing method. (Fig. 7), 7 is a resistor thin film, 8
is an electrode thin film, (Fig. 7(a)) is a resistor thin film deposition process, (
FIG. 7(b)) is an individual heating resistor patterning process by photolithography, (FIG. 7(c)) is an electrode thin film forming process, (FIG. 7(d)) is an electrode patterning process by photolithography,
(FIG. 7(e)) is a protective layer forming step. As shown in FIG. 7, conventionally, a resistor thin film 7 such as tantalum nitride or an electrode thin film 8 such as gold is formed by vapor deposition, and then individual electrodes are formed using a series of lithographic techniques including resist coating, exposure, development, and etching. 1. The print head substrate is manufactured by patterning the common electrode 2 and the individual heating resistors 3, and finally forming the protective layer 6. This print head substrate has a uniform and homogeneous heat generating resistor film, and the pattern shapes of the individual heat generating resistors 3, individual electrodes 1, and common electrode 2 are uniform, and the edges are sharp, resulting in high printing quality. Obtainable.

0004

[Problems to be Solved by the Invention] However, the above-mentioned conventional method for manufacturing print head substrates involves processes such as vapor deposition, exposure, and etching that require expensive equipment and many man-hours, resulting in high manufacturing costs. The problem was that it became In order to reduce the cost of print heads, attempts have been made to print wiring using the screen printing method, but conventional print head boards used as thermal head boards have a heating resistor width of around 100 microns and a minimum electrode width of around 30 microns. Because a fine pattern with a heating resistor pitch of 125 microns is required, it is difficult to manufacture using a screen printing method using a mesh plate, and it can only be manufactured with high precision using lithographic technology, which requires a lot of man-hours. I couldn't do that.

The present invention solves the above conventional problems, and provides a low-cost and high-performance print head substrate, particularly a print head substrate for a thermal head having individual heating resistors, and an easy print head using a new printing process. The purpose of the present invention is to provide a method for manufacturing a substrate.

[0006]

[Means for Solving the Problems] In order to achieve this object, the method for manufacturing a print head substrate of the present invention involves first applying ink from an intaglio plate such as a glass intaglio plate onto the surface of a rubber roller having mold releasability such as silicone rubber. By an intaglio offset printing method in which the ink is transferred from the rubber roller onto the substrate, the ink has a length-to-width ratio of 3 or more and a cross-sectional shape perpendicular to the direction of current flow. The print head substrate of the present invention has a configuration that includes at least the step of printing the individual heating resistors having the above-mentioned arcuate convex portions and the step of printing electrode wiring by the intaglio offset printing method, and the print head substrate of the present invention has a width The length ratio to
It has an individual heating resistor having three or more arcuate convex portions, and further has a configuration in which it has a required number or more of individual heating resistors.

[0007]

[Operation] With the above configuration, in the manufacturing method of the present invention,
It is possible to print fine wiring of tens of microns as well as individual heating resistors without using conventional lithographic techniques. This is because the ink is transferred from the intaglio plate, which has a constant groove width and uniform groove shape, onto the rubber roller, and the solvent of the transferred ink is absorbed into the surface rubber, making it difficult for the ink to collapse, eliminating short circuits. , it is possible to print fine lines with good linearity. In addition, the ink transferred onto the rubber roller is completely printed on the substrate due to the releasability of the rubber roller, making it possible to print a relatively thick film of several microns in thickness. Fine lines can also be printed on glazed alumina substrates that have undulations of ten microns. On the other hand, when manufacturing a print head substrate using a printing method, especially a thermal head substrate with performance close to that of a thin film type, it is possible to print individual heating resistor dots using the above-mentioned intaglio offset printing method; , if we print a discrete heating resistor with a length-to-width ratio of 2, we get
Since the printed film thickness varies at the beginning and end of the printed individual heating resistor (the printing start and end of the printed resistor), it is difficult to manufacture a thermal head with small resistance value variations. (Resistance variation is limited to within ±10%.) Furthermore, the cross-sectional shape of the individual heating resistors printed by the intaglio offset printing method, which is perpendicular to the current direction, is arcuate, and when manufacturing the thermal head, the glaze is applied from the bottom layer. Since the glass component diffuses from the upper layer into the individual heating resistor, the formed individual heating resistor has the lowest specific resistance near the center of its cross section. Therefore, current paths tend to concentrate. Therefore, in the print head substrate of the present invention, for example, long heating resistor dots having a length to width ratio of 5 or more are printed twice with a slightly shifted pitch, and the length to width ratio is 3. By forming an individual heating resistor whose cross-sectional shape perpendicular to the direction of current flow has two arcuate convex portions, the heat generation distribution within each dot is more uniform. A heating resistor is realized. This uses the vicinity of the center of the printed individual heating resistor as the heating part, and forms two arcuate convex parts to separate or enlarge the heating center, thereby achieving more uniform heating. As a result, very excellent printing quality can be obtained. Furthermore, when forming individual heating resistor dots using the intaglio offset printing method, the resistance values of the resistors at both ends of the individual heating resistor array tend to vary, and the resistance values may become higher or lower, albeit slightly. However, in the method for manufacturing a print head of the present invention, a board having a length longer than a predetermined length in the width direction of the individual heating resistors is used to print more than the required number of individual heating resistors, thereby achieving the final required predetermined length. By cutting out the part, the above-described peculiar part of the resistance value can be removed. As described above, the print head substrate manufacturing method and print head substrate of the present invention can produce print head substrates with high performance of 8 dots/mm or more, which could not be manufactured without using lithography technology, without using lithography technology. Furthermore, the print head substrate can be manufactured using a simple process and inexpensive printing technology, and furthermore, it is possible to realize a print head substrate at a much lower cost than in the past.

[0008]

Embodiments (Embodiment 1) A first embodiment of the print head substrate of the present invention will be described below with reference to the drawings. (FIG. 1) is a configuration diagram of a heat generating portion of a print head substrate having individual heating resistors, which is manufactured using the intaglio offset printing method of the present invention. In (Fig. 1), 1 is an individual electrode, 2 is a common electrode, 3 is an individual heat generating resistor, 9 is a heat generating part length T, 10 is an individual heat generating resistor length L, 11 is a cutting line, 12 is an individual heat generating resistor is the printing direction. Also, the protective layer is not shown for purposes of explanation. A ruthenium/titanium-based organic metal paste was used for the resistor ink. (Fig. 1), the individual heating resistor length L10 is longer than the heating part length T9, and the heating part length T
is 150 microns, the length L of the individual heating resistor is 400 microns, and the width of the individual heating resistor 3 is 110 microns. In this case, a dot-shaped heat generation distribution with a width of about 100 microns and a length of about 150 microns is obtained. (Figure 2) is (Figure 1
) is a cross-sectional view of the individual heating resistor taken along the cutting line 11 of FIG. As shown in FIG. 2, the cross-sectional shape of the individual heat generating resistor 3 of this thermal head substrate consists of two arcuate convex portions. This individual heating resistor 3 has a width of 70 μm and a length of 4
00 micron resistor dots are shifted by 30 microns to 2
Formed by printing twice. Moreover, the gold electrode was formed by an intaglio offset printing method. The resistance value variation of this thermal head substrate was ±5% (total 1728 dots). In this thermal head, since the cross-sectional shape of the individual heating resistor 3 consisted of two arcuate convex portions, the heat generation center tended to be divided into two locations, and the heat generation in each resistor was more uniform. As a result of a printing test after forming the glass protective layer, a printed dot shape comparable to that of a thin film thermal head was obtained. Further, when the length L of the individual heating resistor was set to 300 microns, there was a variation in resistance value of ±10% or more, and good reproducibility could not be obtained. In the present invention, the number of arcuate convex portions may be three or as many as possible. However, when forming individual heating resistors using the intaglio offset printing method, as the printing line width becomes narrower, the printing thickness tends to also become thinner. It is necessary to set the number of copies.

(Embodiment 2) A second embodiment of the print head substrate of the present invention will be described below with reference to the drawings. (FIG. 3) is a schematic external view of the print head substrate of the present invention, which is a thermal head substrate having individual heating resistors. For illustrative purposes, the protective layer is not shown. In FIG. 3, 13 is a number of individual heating resistors greater than the required number, and 14 is a glazed alumina substrate. In this case, the glass intaglio plate used has grooves for individual heating resistors, which are larger than necessary and have 64 dots on each side of a predetermined row of individual heating resistors. When a thermal head board is prototyped using a glass intaglio plate that does not have grooves for individual heating resistors in excess of the required number,
There is a tendency for the resistance values of the individual heating resistors at both ends, especially the resistance values of several dots, to be several percent higher or lower than the overall average resistance value. Although the cause of this is not clear, it is believed that it is due to deformation of the surface rubber during printing. On the other hand, in this example, the resistance value is several percent
Since the changing portions are ineffective as printed dots, it was possible to achieve a resistance value variation of ±4%, which is even lower than that of the thermal head substrate described in Example 1. Incidentally, gold electrodes may be formed on the individual heating resistors 13 in excess of the required number and used as dots for resistor evaluation (resistance value evaluation). Note that in the present invention, the print head substrate is not limited to the thermal head described in the above embodiments, but may be an inkjet print head substrate that uses individual heating resistors, for example.

(Embodiment 3) A first embodiment of the method for manufacturing a print head substrate according to the present invention will be described below with reference to the drawings. (FIG. 4) is a manufacturing process diagram of a print head substrate showing a manufacturing process of a thermal head substrate having individual heating resistors as a method of manufacturing a print head substrate of the present invention. In (Figure 4), (Figure 4 (a))
4(b) is a resistor printing process in which the individual heat generating resistors 3 are printed by printing two or more times using an intaglio offset printing method using a silicone rubber roller and a glass intaglio plate, and (Fig. 4(b)) is a resistor printing process in which the individual heat generating resistors 3 are fired. The resistor firing process (Fig. 4 (
c)) Individual electrodes 1 are printed using the same intaglio offset printing method.
and the electrode printing process of printing the common electrode 2 (FIG. 4(d))
is an electrode firing process that metalizes printed electrode wiring,
(FIG. 4(e)) is a protective layer forming step for forming the protective layer 6. First, on a glazed alumina substrate 14 from which six cleaned A4-sized thermal head substrates can be obtained, more than the required number of individual heating resistor dots are printed twice at different pitches using an intaglio offset printing method, and the length relative to the width is The individual heat generating resistor 3 has a ratio of 3 and has two arcuate convex sections in a cross section perpendicular to the direction of current flow.
was printed. Ruthenium/titanium-based metallo-organic paste was used for the resistor ink. After that, 75
A resistor film was formed by firing in air at 0°C. Next, the individual electrode 1 and the common electrode 2 are intaglio offset printed using metallo-organic gold paste, and this is
The gold was metallized by firing at 0°C. Next, the glass paste was screen printed and then baked at 750°C to form the protective layer 6. Finally, this was divided into six pieces to create a thermal head board. The resistance value variation of this thermal head substrate was ±4%. In addition, (Figure 4(c))
Then, in order to lower the gold wiring resistance value, redundant printing may be performed, such as printing twice in succession at the same position to increase the thickness of the wiring. In this embodiment, the manufacturing process and print head substrate are not limited to this embodiment.

(Embodiment 4) A second embodiment of the method for manufacturing a print head substrate according to the present invention will be described below with reference to the drawings. (FIG. 5) is a print head substrate manufacturing process diagram showing a manufacturing process of an A4 size thermal head substrate having individual heating resistors as a method of manufacturing a print head substrate of the present invention. In (Figure 5), (
Fig. 5(a) shows a resistor printing process in which individual heating resistors 3 are printed by printing two or more times on a B4 size substrate by an intaglio offset printing method using a silicone rubber roller and a glass intaglio plate. 5(b)) is the individual heating resistor 3
(Fig. 5(c)) is an electrode printing process in which individual electrodes 1 and common electrodes 2 are printed by a similar intaglio offset printing method; (Fig. 5(d)) is the printed electrode wiring. The electrode firing step (FIG. 5(e)) is a protective layer forming step for forming the protective layer 6. (Figure 5(f)
)) is a cutting process in which a B4 size board is cut into a predetermined A4 size. First, printing was performed twice using an intaglio offset printing method on a glazed alumina substrate 14 from which six cleaned B4-sized thermal head substrates were obtained, and the length to width ratio was 3, and the direction of current flow was A required number or more (a number equivalent to B4 size) of individual heat generating resistors 3 having two arc-shaped convex sections in a cross section perpendicular to each other were printed. Ruthenium/titanium-based metallo-organic paste was used for the resistor ink. After that, 750℃,
Baked in air. Next, A4 size individual electrodes 1 and common electrodes 2 were intaglio offset printed using a metallo-organic gold paste, and this was fired at 750° C. to metallize the gold. Next, after screen printing the glass paste and baking it at 750°C to form the protective layer 6 for A4 size, cut the B4 size board into a predetermined A4 size, and then divide this into 6 pieces. An A4 size thermal head board was created. The resistance value variation of this thermal head substrate was ±3.5%. In this manufacturing method, by printing the individual heating resistors 3 to the full B4 size and using the central portion where the resistance values are less likely to vary, it was possible to manufacture a thermal head substrate with very small variations in resistance values. In addition, in this manufacturing method, (Fig. 5
In (c)), redundant printing may be performed such as printing twice in succession at the same position to increase the thickness of the wiring in order to lower the gold wiring resistance value. Furthermore, in this example,
The manufacturing process and print head substrate are not limited to the thermal head substrate of this embodiment.

0012

As described above, the present invention provides a method for manufacturing a print head substrate in which ink is once transferred from an intaglio plate such as a glass intaglio plate onto the surface of a rubber roller having mold releasability such as silicone rubber, and then the ink is transferred to the surface of a rubber roller having release properties. Using the intaglio offset printing method, which transfers images from a rubber roller onto a substrate,
A step of printing an individual heating resistor having a length-to-width ratio of 3 or more and having two or more arc-shaped convex sections in a cross section perpendicular to the direction of current flow, and the above-mentioned intaglio offset printing method. In addition, in the print head substrate of the present invention, the length to width ratio is 3 or more, and the shape of the cross section perpendicular to the direction of current flow is provided. By providing a configuration characterized by having individual heating resistors having two or more arcuate convex portions, and furthermore having a number of individual heating resistors greater than the required number, manufacturing costs are high. A print head substrate manufacturing method that allows the print head substrate to be easily manufactured without using lithography technology, which has a complicated process, and a method that has high performance comparable to that of conventional thin film print head substrates and is low cost. This makes it possible to realize a print head board with a high level of functionality.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a heat generating section of a print head board in a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an individual heating resistor of a printhead substrate in a first embodiment of the present invention.

FIG. 3 is a schematic external view of a print head board in a second embodiment of the present invention.

FIG. 4 is a manufacturing process diagram showing a method of manufacturing a print head substrate in a third embodiment of the present invention.

FIG. 5 is a manufacturing process diagram showing a method of manufacturing a print head substrate in a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a print head board showing a conventional example.

FIG. 7 is a manufacturing process diagram showing a conventional method of manufacturing a print head substrate.

[Explanation of symbols]

1 Individual electrode 2 Common electrode 3. Individual heating resistor 4 Glaze layer 5 Alumina substrate 6 Protective layer 7 Resistor thin film 8 Electrode thin film 9 Heat generating part length T 10 Individual heating resistor length L 11 Cutting line 12 Printing direction of individual heating resistors 13. More individual heating resistors than necessary 14 Glazed alumina substrate

Claims (5)

[Claims] [Claim 1] The length to width ratio is 3 or more,
A print head substrate comprising an individual heating resistor having two or more arc-shaped convex portions in a cross section perpendicular to the direction of current flow. 2. The print head board according to claim 1, further comprising a required number or more of individual heating resistors. 3. An intaglio offset printing method in which ink is once transferred from an intaglio onto the surface of a rubber roller having mold releasability, and then the ink is transferred from the rubber roller onto a substrate, so that the length to width ratio is 3 or more. and a step of printing an individual heating resistor having two or more arc-shaped convex portions in a cross section perpendicular to the direction of current flow, and a step of printing electrode wiring by the intaglio offset printing method. A method for manufacturing a print head substrate, comprising at least the following. 4. A substrate longer than a predetermined length in the width direction of the individual heating resistor is used, and an intaglio offset printing method is used on the substrate so that the length to width ratio is 3 or more and the current a step of printing a necessary number or more of the individual heating resistors each having a cross section perpendicular to the flow direction having two or more arcuate convex portions; a step of printing electrode wiring by the intaglio offset printing method; A method for manufacturing a print head substrate, the method comprising at least the steps of cutting an ineffective portion and forming a protective layer. 5. The production of a print head substrate according to claim 3, wherein the intaglio plate used in the intaglio offset printing method is a glass intaglio plate, and the rubber roller surface is made of silicone rubber. Method.