JPH0761015A - Manufacture of thick film type thermal print head - Google Patents

Abstract

PURPOSE:To contrive to densify printing density in a thick film type thermal print head, in which a large number of first electrode pattern and a large number of second electrode pattern are formed on the top surface of insulating board under the state that both the electrode patterns penetrate into each other and, at the same time, a line type thick film heating resistor 4 is formed so as to cross both the electrode patterns. CONSTITUTION:Boarder parts 2a and 3a, at which the interval between respective electrode pattens is made narrower widthwise are integrally shaped and formed at least at the sites on one side edge 4b in the width direction of a thick film heating resistor of first electrode pattern 2 or second electrode pattern 3 or the first electrode pattern and the second electrode pattern. Next, after the thick film heating resistor 4 is formed so as to overlap the portion, which ranges by proper dimension from at least one side edge 4b in the width direction of the thick film heating resistor, with the broader parts, electric power, which is higher than that applied at printing, is applied to the respective first electrode pattern and second electrode pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thick film type thermal print head which has a high printing density among thermal print heads used in facsimiles and the like.

[0002]

2. Description of the Related Art A thick film type thermal print head of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-192666, and as shown in FIGS. 9 and 10, an upper surface of an insulating substrate 11 made of ceramic or the like. The first of a number of comb-shaped
The electrode pattern 12 and a large number of second electrode patterns 13 which are also arranged in the shape of a comb are arranged on both electrode patterns 12,
Each of the second electrode patterns 13 among 13 is formed so as to enter between the first electrode patterns 13, and
By forming the thick film heating resistor 14 extending in a line shape so as to cross both the first electrode pattern 12 and the second electrode pattern 13, the first electrode pattern 12 of the thick film heating resistor 14 is formed. And the second electrode pattern 13
The portion between and is one printing dot 14a (the portion hatched with parallel diagonal lines in FIG. 9).

The printing density in this thick film type thermal print head is as follows:
4 is determined by the number of print dots 14a existing per unit length along the longitudinal direction of No. 4, the width of each of the first electrode patterns 12 and the second electrode patterns 13 can be increased in order to increase the print density. While reducing the dimension S, each first electrode pattern 12 and each second electrode pattern 13
It is necessary to reduce the pitch interval P between the and.

[0004]

By the way, each of the first
The electrode pattern 12 and each second electrode pattern 13 are formed by a photolithography method in which a thin metal layer formed by screen printing or sputtering on the upper surface of the insulating substrate 11 is photoetched, as is well known in the art. Therefore, each of the first electrode patterns 1
2 and the pitch interval P and the width dimension S in each second electrode pattern 13 have a print density of, for example, 400 dpi (the number of the heating dots 14a existing per inch along the longitudinal direction of the line-shaped thick film heating resistor 14). It can be relatively easily adapted to high density up to about 400).

On the other hand, however, the line-shaped thick film heating resistor 14 has a screen plate having a slit groove A1 of width W corresponding to the line thick film heating resistor 14 as shown in FIG. A is an insulating substrate 1 on which the first electrode patterns 12 and the second electrode patterns 13 are formed in advance.
1 is formed by a screen printing method in which the slit plate A1 of the screen plate A is filled with the material paste of the thick film heating resistor 14 and then the screen plate A is removed. According to this screen printing method, the minimum value in the width dimension W of the thick film heating resistor 14 is limited to 130 to 140 μm and cannot be made smaller than this (if it is made smaller, slit A part or all of the paste filled in the slot A1 will be carried away together when the screen plate A is removed from the insulating substrate 11, so that the thick film heating resistor 14 is formed by screen printing. The yield rate at that time is significantly reduced).

Therefore, the pitch interval P between the first electrode patterns 12 and the second electrode patterns 13 is set to 40.
Each heating dot 14a formed between each first electrode pattern 12 and each second electrode pattern 13 even if the printing density is 31.75 microns that can realize a printing density of 0 dpi.
Since the dimension of the line-shaped thick film heating resistor 14 in the direction perpendicular to the longitudinal direction cannot be set to be equal to or smaller than the minimum width dimension W of the thick film resistor 14 in FIG.
4a is a rectangle that is vertically long with respect to the longitudinal direction of the line-shaped thick film heating resistor 14, in other words, the print dot size in the longitudinal direction of the line-shaped thick film heating resistor 14 is perpendicular to the longitudinal direction. This is significantly larger than the print dot size in the longitudinal direction of the heating resistor 14.

That is, in the thick film type thermal print head manufactured by the conventional manufacturing method, since the print dot size in the direction perpendicular to the longitudinal direction of the line-shaped thick film heating resistor cannot be reduced, the printing density is high. There is a problem that there is a certain limit value for densification. The present invention provides a manufacturing method capable of reliably achieving high print density without increasing the print dot size in the direction perpendicular to the longitudinal direction of the line-shaped thick film heating resistor in each print dot. This is a technical issue.

That is, when the present inventor applies a higher electric power to the thick film heating resistor than that applied during normal printing, the thick film heating resistor changes so that its resistance value becomes high. The present invention has been completed by paying attention to the fact that it does.

[0009]

In order to achieve this technical object, "claim 1" in the present invention states that "a plurality of first electrode patterns arranged in a comb shape on the upper surface of an insulating substrate, and A plurality of second electrode patterns arranged in a comb shape are formed so that each of the second electrode patterns of these two electrode patterns is inserted between the respective first electrode patterns, and then extended in a line shape. A method of manufacturing a thermal print head, wherein a thick film heating resistor is formed so as to cross both the first electrode pattern and the second electrode pattern,
A portion of the first electrode pattern or the second electrode pattern at one side edge of the thick film heating resistor in the width direction of the first electrode pattern or the second electrode pattern, or the first electrode pattern and the second electrode pattern. And integrally forming a wide portion in which a space between the first electrode pattern and the second electrode pattern is narrowed, and then, the thick film heating resistor is connected to the thick film heating resistor. Of the width dimension of the resistor, a portion having a proper dimension from one side edge is formed so as to overlap with the wide portion, and then each of the first electrode patterns and each of the second electrode patterns is provided with an electric power during printing. Also applies high power. I adopted the method of saying.

Further, the "claim 2" in the present invention is
“On the upper surface of the insulating substrate, a large number of first electrode patterns arranged in a comb shape and a large number of second electrode patterns arranged in a comb shape are formed as a second electrode pattern of the two electrode patterns. Thermal printing in which each is formed so as to be inserted between the first electrode patterns, and then a thick film heating resistor extending in a line shape is formed so as to cross both the first electrode pattern and the second electrode pattern. In the method of manufacturing a head, the first electrode pattern and the second electrode pattern are replaced with the first electrode pattern or the second electrode pattern,
Alternatively, a space between the first electrode pattern and the second electrode pattern is partially formed at a side edge portion and a side edge portion in the width direction of the thick film resistor of the first electrode pattern and the second electrode pattern. The first wide portion and the second portion
The wide portion is integrally formed and formed, and then the thick film heating resistor is formed such that a portion of the width dimension of the thick film heating resistor, which is appropriately sized from one side edge, is with respect to the first wide portion. ,
After forming a portion of an appropriate size from the other side edge to overlap with the second wide portion, a power higher than that during printing is applied to each of the first electrode patterns and each of the second electrode patterns. Apply. I adopted the method of saying.

[0011]

[Operation] In this configuration, when applying to normal printing, each print dot formed between each first electrode pattern and each second electrode pattern of the thick film heating resistor is A power higher than the power is applied. Then, in the portion corresponding to the wide portion of each print dot, the resistance value between the first electrode pattern and the second electrode pattern in the portion is the resistance value in the portion other than the wide portion of the print dot. Since a smaller current than that causes a large current to flow, it generates heat at a high temperature and has a high resistance.
It can be electrically opened or insulated from normal printing power.

As a result, the heat generated by the normal printing power is generated only in the portion of each print dot excluding the portion corresponding to the wide portion. Therefore, the line shape in the portion of the print dot that actually generates heat during printing. The dimension of the thick film heating resistor in the direction perpendicular to the longitudinal direction, that is, the print dot size in the direction perpendicular to the longitudinal direction of the thick film heating resistor, is larger than the width of the thick film heating resistor. It is possible to reduce only the size of the width dimension of the width overlapping the wide portion.

[0013]

As described above, according to the present invention, the print dot size in the direction perpendicular to the longitudinal direction in the line-shaped thick film heating resistor can be reduced, so that the printing density in the thick film type thermal print head can be increased. This has the effect of reliably achieving high temperature without causing a reduction in the yield rate when screen-printing the thick-film heating resistor.

In particular, according to the constitution of "Claim 2", in addition to the above-mentioned effects, the thick film heating resistor is excluded except for the portions of the thick film heating resistor where the thickness dimensions are not uniform on the left and right edges. A portion of the center portion in the width direction in which the thickness dimension is substantially uniform can be a substantial print dot for actual printing, so that the print quality can be further improved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment. First, a large number of first electrode patterns 2 arranged in a comb shape and a large number of second electrode patterns 3 arranged in a comb shape are formed on the upper surface of an insulating substrate 1 made of ceramic or the like. Pattern 2,
Each of the second electrode patterns 3 among the third electrode patterns 3 is formed so as to be inserted between the first electrode patterns 2, and then the thick film heating resistor 4 extending in a line shape is formed. It is formed so as to traverse both of the electrode patterns 3.

When forming each of the first electrode patterns 2 and each of the second electrode patterns 3 on the upper surface of the insulating substrate 1, it is formed on the upper surface of the insulating substrate 1 by screen printing, sputtering or the like as in the conventional case. The thin metal layer is formed by a photolithography method called photo-etching. In this case, the first electrode patterns 2 and the second electrode patterns 3 have the first electrode patterns 2 and the second electrode patterns. In the electrode pattern 3, a first edge 4b in the width direction of the thick film heating resistor 4 is provided with a first
The wide portions 2a and 3a, which are designed to partially narrow the gap between the electrode pattern 2 and the second electrode pattern 3, are integrally formed and formed.

Next, in the thick film heating resistor 4, a portion of the width W of the thick film heating resistor 4 from the one side edge 4b to the appropriate dimension W2 is overlapped with the wide portions 2a and 3a. To form. As a result, the print dots 4a are formed on each of the portions of the thick film heating resistor 4 between the first electrode patterns 2 and the second electrode patterns 3.

Therefore, an electric power higher than that during printing is applied between each of the first electrode patterns 2 and each of the second electrode patterns 3. Then, by applying a power higher than the power applied during normal printing to each of the print dots 4a, a portion 4a ″ corresponding to the wide portions 2a, 3a of each print dot 4a is applied. (In FIG. 2, a portion hatched to the right with parallel diagonal lines) corresponds to the wide portion of the print dot 4a when the resistance value between the first electrode pattern 2 and the second electrode pattern 3 in the portion 4a ″ corresponds to the wide portion. The portion 4a 'other than the portion (in FIG. 2,
Since a large current flows, which is smaller than the resistance value in the downward-sloping parallel hatched portion) and heats up to a high temperature to increase the resistance, the wide portion 2a of each print dot 4a,
The portion 4a ″ corresponding to 3a can be electrically opened or insulated with respect to normal printing power.

As a result, only the portion 4a 'of each print dot 4a excluding the portion 4a "corresponding to the wide portion is heated by the normal print power. Therefore, the print dot 4a is actually printed. The dimension W1 in the direction perpendicular to the longitudinal direction of the line-shaped thick film heating resistor 4 in the heat generating portion 4a ′, that is, the print dot size in the direction perpendicular to the longitudinal direction of the thick film heating resistor 4, is set to the thick film heating resistor 4 It is possible to reduce the width dimension W of the thick film heating resistor 4 by a dimension W2 overlapping the wide portions 2a and 3a.

Wide portions 2a, 3a for narrowing the space between each of the first electrode patterns 2 and each of the second electrode patterns 3.
On the basis of its intent, as in the second embodiment shown in FIG. 4, the wide portion 3a is formed only for each second electrode pattern 3, or the third portion shown in FIG. In the embodiment, the wide portion 2a is formed only for each first electrode pattern 2, or as in the fourth embodiment shown in FIG. Each second
A wide portion 2a protruding only from one side surface of the electrode pattern 3,
3a may be used.

7 and 8 show a fifth embodiment. In the fifth embodiment, each first electrode pattern 2 and each second electrode pattern 3 are first formed on the upper surface of the insulating substrate 1,
Next, when forming the line-shaped thick film heating resistor 4, the first electrode patterns 2 and the second electrode patterns 3 are replaced with the first electrode patterns 2 and the second electrode patterns 3.
Of the thick film heating resistor 4, one side edge 4 in the width direction
The first electrode pattern 2 and the second electrode pattern 3 are provided at the portion b.
The first wide portion 2 in which the space between
a ', 3a' are provided with second wide portions 2a ", 3a" at the other side edge 4c so as to partially narrow the gap between the first electrode pattern 2 and the second electrode pattern 3 as well. Each is integrally formed and formed.

Next, in the thick film heating resistor 4, the portion of the width dimension W of the thick film heating resistor 4 from the one side edge 4b to the appropriate dimension W2 is relative to the first wide portions 2a 'and 3a'. Then, the portion of the dimension W3 from the other side edge 4c is the second
After the wide portions 2a ″ and 3a ″ are formed so as to overlap with each other, by applying a power higher than the power during printing between the first electrode patterns 2 and the second electrode patterns 3, Of the print dots 4a in the thick film heating resistor 4, the first wide portions 2a ', 3a' and the second wide portions 2a ', 3a'
A portion 4a "corresponding to the wide portions 2a" and 3a "(a portion hatched by parallel slant lines rising to the right in FIG. 7) flows a large current, generates heat at a high temperature to have a high resistance, and has a normal printing power. Is electrically opened or insulated with respect to the first wide portion 2a ', 3a' and the second wide portion 2a "of the print dots 4a.
Since there is only a portion 4a 'excluding the portion 4a "corresponding to 3a" (a portion hatched in FIG. 7 by a diagonally right downward slanted line), a line in a portion 4a' of this print dot 4a that actually generates heat during printing. The dimension W1 of the thick film heating resistor 4 in the direction perpendicular to the longitudinal direction, that is, the print dot size in the direction perpendicular to the longitudinal direction of the thick film heating resistor 4, is smaller than the width W of the thick film heating resistor 4. Of the width W of the thick-film heating resistor 4, the size W2 that overlaps the first wide parts 2a ′ and 3a ′ and the size W3 that overlaps the second wide parts 2a ″ and 3a ″ can be reduced. .

Further, according to the fifth embodiment, the thick film heating resistor 4 is excluded except for the portions of the left and right side edges 4b and 4c of the thick film heating resistor 4 which are not uniform in thickness.
Of these, a portion in which the thickness dimension is substantially uniform in the substantially central portion in the width direction can be a substantial printing dot for actual printing. In the fifth embodiment as well, the first wide portions 2a 'and 3a' and the second wide portion 2 are formed.
It is needless to say that a ″ and 3a ″ may be in the form of the second embodiment shown in FIG. 4, the third embodiment shown in FIG. 5, or the fourth embodiment shown in FIG. Is.

[Brief description of drawings]

FIG. 1 is an enlarged plan view of an essential part showing a state before a thick film heating resistor is formed in a first embodiment of the present invention.

FIG. 2 is an enlarged plan view of an essential part showing a state after the thick film heating resistor is formed in the first embodiment of the present invention.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged plan view of an essential part showing a second embodiment of the present invention.

FIG. 5 is an enlarged plan view of an essential part showing a third embodiment of the present invention.

FIG. 6 is an enlarged plan view of an essential part showing a fourth embodiment of the present invention.

FIG. 7 is an enlarged plan view of essential parts showing a fifth embodiment of the present invention.

8 is an enlarged sectional view taken along line VIII-VIII of FIG. 7.

FIG. 9 is an enlarged plan view of an essential part showing a conventional example.

10 is a cross-sectional view taken along line XX of FIG.

FIG. 11 is a perspective view showing a state in which a thick film heating resistor is formed on an insulating substrate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 1st electrode pattern 3 2nd electrode pattern 2a, 2a ', 2a "Wide part 3a, 3a', 3a" in 1st electrode pattern Wide part 4 in 2nd electrode pattern 4 Thick film heating resistor 4a Print dot 4b One side edge of the thick film heating resistor 4c Other side edge of the thick film heating resistor

Claims (2)

[Claims] 1. A plurality of first electrode patterns arranged in a comb shape and a plurality of second electrode patterns arranged in a comb shape on the upper surface of an insulating substrate. Each of the two electrode patterns is formed so as to be inserted between the respective first electrode patterns, and a thick film heating resistor extending in a line shape is formed so as to traverse both the first electrode pattern and the second electrode pattern. In the method of manufacturing a thermal print head to be formed, the first electrode pattern and the second electrode pattern are replaced by the thick film heating resistor of the first electrode pattern or the second electrode pattern, or the first electrode pattern and the second electrode pattern. At one side edge portion in the width direction of the body, a wide portion is formed integrally so as to partially narrow the gap between the first electrode pattern and the second electrode pattern. After the thick film heating resistor is formed such that a portion of the width dimension of the thick film heating resistor, which has an appropriate dimension from one side edge, overlaps the wide portion, A method for manufacturing a thick film type thermal print head, characterized in that a power higher than a power during printing is applied to each second electrode pattern. 2. A plurality of first electrode patterns arranged in a comb-teeth shape and a plurality of second electrode patterns arranged in a comb-teeth shape on the top surface of an insulating substrate Each of the two electrode patterns is formed so as to be inserted between the respective first electrode patterns, and a thick film heating resistor extending in a line shape is formed so as to traverse both the first electrode pattern and the second electrode pattern. In the method of manufacturing a thermal print head to be formed, the first electrode pattern and the second electrode pattern are replaced by the thick film heating resistor of the first electrode pattern or the second electrode pattern, or the first electrode pattern and the second electrode pattern. A first portion in which a space between the first electrode pattern and the second electrode pattern is partially narrowed at a side edge portion and a side edge portion in the width direction of the body.
The wide portion and the second wide portion are integrally formed and formed, and then the thick film heating resistor is formed such that a portion of the width dimension of the thick film heating resistor is appropriately sized from one side edge. The wide portion is formed so that a portion having an appropriate size from the other side edge is overlapped with the second wide portion, and then the first electrode pattern and the second electrode pattern are printed at the time of printing. A method for manufacturing a thick film type thermal print head, characterized in that a power higher than the power is applied.