JPH07148955A - Thermal printing head substrate - Google Patents

Abstract

PURPOSE:To improve the contact of the printing part of a thermal printing head with a platen by suppressing the protuberance caused by the interference of a common wiring pattern with a heating resistor as low as possible while achieving the reduction of a voltage drop. CONSTITUTION:In a thermal printing head substrate 1 wherein a heating resistor 3, a common wiring pattern 5 and a heating control wiring pattern are provided on a material substrate 2 and a common wiring reinforcing layer 10 is formed on the surface of the common wiring pattern 5, the place 11 not forming the common wiring reinforcing layer is allowed to be present at a part where the common wiring pattern 5 interferes with the end part of the heating resistor 3 or the part passing the vicinity of the end part of the heating resistor 3. Pref., a membrane reinforcing layer 14 composed of a conductive metal thinner than the common wiring reinforcing layer is formed to the place 11 not forming the common wiring reinforcing layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printhead substrate, and more particularly to a thermal printhead substrate used in serial line printers, facsimiles, word processors, tape writers and the like.

[0002]

2. Description of the Related Art A so-called line type thermal print head is usually constructed so that a linearly extending heating resistor formed on a substrate is driven by a driving IC for each predetermined number of dots.

Specifically, for example, Japanese Patent Laid-Open No. 5-8494.
As disclosed in Japanese Unexamined Patent Publication No. 6, a common wiring pattern extending from an external connection terminal portion along an edge of a substrate and then bent and routed to one side of the heating resistor, and the heating resistor. Various patterns, such as individual electrode patterns for heat generation control, which are formed on the other side of the body to reach the drive IC arrangement portion, are arranged on the substrate.

A comb-teeth-shaped individual electrode pattern extending from the drive IC side to the heat-generating resistor is inserted between each comb-teeth-shaped unit common pattern extending from the common wiring pattern to the heat-generating resistor. Then, the drive IC
The individual electrode pattern for heat generation control is ON / OFF controlled by the above, whereby each dot divided in the longitudinal direction of the heat generating resistor is individually controlled and generates heat.

In this case, due to the control mode for heating the heating resistor, the current capacity of the common wiring pattern may be insufficient, which may cause a sharp increase in the voltage drop. A common wiring reinforcing layer is formed along the surface of the wiring pattern for wiring. The common wiring reinforcing layer is formed thicker than the other patterns illustrated above.

The common wiring pattern and the heat generation controlling individual electrode pattern are formed by using an organic gold paste having good conductivity, and the common wiring reinforcing layer is formed by using a silver paste or a silver / palladium paste. It is usually formed. As the material of the heating resistor, ruthenium oxide is used, for example.

[0007]

By the way, in the thermal print head substrate disclosed in the above publication, the common wiring pattern extends in the width direction along one side edge of the substrate. As shown in FIG. 6, when the width of the head substrate 50 is narrow, the common wiring pattern 51
The portion along the edge of the substrate and the both ends of the heating resistor 52 interfere with each other.

As described above, the heating resistor 52 extends from one edge to the other edge of the substrate 50 in that each type of substrate is manufactured in the same wiring pattern and drive as shown in the drawing. This is performed by forming ICs at a plurality of positions in the width direction or at a plurality of positions in the vertical and horizontal directions, stacking a single heating resistor 52 along the width direction of the parent substrate, and then cutting out as individual head substrates. Because. In addition, in order to make the effective print width of a narrow print head such as a tape writer as long as possible, it is preferable to extend the heating resistor 52 in the width direction as described above.

As shown in FIG. 7, since the common wiring reinforcing layer 53, which is thicker than the other patterns, is formed on the surface of the common wiring pattern 51, it interferes with the heating resistor 52. There is a problem that the end portion of the head substrate 50, which is a portion, is partially raised. In addition,
A glass protective film 55 is formed on the outermost surface of the substrate 50 by using a thick film printing method. Needless to say, the both end parts 50a, 50a of the printing part of the thermal print head obtained by this method are, of course, Raising occurs.

Along with this, the contact state between the printing portion of the thermal print head and the platen or the object to be printed deteriorates, and the feeding of the object to be printed varies, or accurate printing cannot be performed. In addition, early wear of the printed portion and deterioration of durability due to this may be caused.

Such a problem similarly occurs when a partial glaze 54 for increasing transfer efficiency is formed on the back side of the heating resistor 52 as shown in FIGS.

Even if the head substrate has a long dimension in the width direction as in the above publication, the heating resistor may extend to the edge of the substrate when it is desired to make the effective print width as long as possible. Therefore, the same problem as described above occurs.

Further, the portion along the longitudinal direction of the surface of the heating resistor 52 corresponds to the printing line, and the common wiring reinforcing layer 53 is usually formed thicker than the heating resistor 52. Considering this, the common wiring pattern 5
Even when 1 passes through the vicinity of the heating resistor 52 without interfering with the end of the heating resistor 52, unnecessary ridges are generated in the print line in the same manner as described above.

The present invention was conceived under the circumstances described above, and the common wiring pattern interferes with or passes through the heating resistor while reducing the voltage drop. It is an object of the present invention to improve the contact between the printing portion and the platen so as to prevent the feeding and the printing action on the printing object from being hindered by suppressing the occurrence of the ridge due to

[0015]

In order to solve the above problems, the present invention takes the following technical means.

That is, the invention according to claim 1 of the present application straddles the heating resistor formed in a straight line from one end to the other end of the substrate and the end of the heating resistor from the external connection terminal. , Or the arrangement of the common wiring pattern that is routed to one side of the heat generating resistor after extending in the substrate width direction after passing through the vicinity of the end and the drive circuit mounted on the other side of the heat generating resistor. In a thermal printhead substrate comprising a heating control individual electrode pattern formed in a region between the heat generating resistor and the heating resistor, and a common wiring reinforcing layer is formed on the surface of the common wiring pattern. The common wiring pattern is characterized in that a non-formation portion of the common wiring reinforcing layer is present at a portion crossing an end of the heating resistor or a portion passing near the end.

Further, in the thermal print head substrate according to claim 2 of the present application, the heating resistor is formed on the surface of the partial glaze.

Further, the thermal print head substrate according to claim 3 of the present application has the same structure as the one according to claim 1 or 2 above, and in addition to the common wiring reinforcing layer, a common wiring reinforcing layer is not formed. A thin film reinforcing layer made of a conductive metal, which is thinner than the wiring reinforcing layer, is formed.

[0019]

According to the present invention, even if the end portion of the heating resistor formed over substantially the entire width direction of the substrate and the common wiring pattern passing through the end portion of the substrate interfere with each other, Since the common wiring reinforcing layer is not formed in this interference portion, a partial protrusion due to this reinforcing layer does not occur. Further, even when the common wiring pattern passes near the heating resistor, the common wiring reinforcing layer is not formed in the vicinity passing portion, so that no bulge is generated in the same manner. This allows
The contact state between the printing portion of the thermal print head and the platen is improved, so that the feeding and the printing action on the printing object are accurately performed.

On the other hand, since the common wiring reinforcing layer is formed at a portion other than the interference portion or the vicinity passing portion in the common wiring pattern, the original purpose is to reduce the voltage drop. Is preferably performed.

Further, regarding the head substrate in which the heating resistor is formed on the surface of the partial glaze for storing heat,
In the same manner as described above, the common wiring reinforcing layer is not formed in the interference part or the vicinity passing part between them, so that the problem that a bulge occurs at the end of the partial glaze corresponding to the print line is avoided.

Further, if a thin film-shaped reinforcing layer is formed in a portion where the common wiring reinforcing layer is not formed so that the common wiring reinforcing layer is not formed, it is possible to suppress partial bulging, and This will make up for the lack of current capacity. As a result, it is possible to surely prevent the occurrence of the voltage drop and also to suppress the protrusion. In this case, if the thin-film reinforcing layer is formed by using the inorganic gold paste, the so-called eating phenomenon due to the interference with the heating resistor when the organic gold paste is used as the wiring pattern is caused and Current flow obstruction is avoided.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the thermal print head substrate according to the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a plan view showing a typical configuration example of a head substrate 1 which constitutes a thermal print head.

Rectangular rectangular material substrate 2 made of ceramic
On the surface of the heating resistor 3, a heating resistor 3 extending linearly in parallel with the side edge of the heating resistor is formed. On one side of the heating resistor 3, there is formed a common wiring pattern 5 extending from the external connection terminal portions 4 and 4 along both edges of the material substrate 2 and then bent at a corner portion, while the other side is formed. The drive IC 6 is arranged in the. Then, an individual electrode pattern 7 for heat generation control is formed at a location from the drive IC 6 to the heat generating resistor 3,
Further, a signal wiring pattern 9 is formed at a location extending from the drive IC 6 to the plurality of external connection terminals 8.

The first embodiment of the present invention will be described with reference to FIG. 2. The common wiring reinforcing layer 1 for reducing the voltage drop is formed on the surface of the common wiring pattern 5.
0 is formed, but the reinforcing layer 10 is formed in a state where the interference portion 11 between the heating resistor 3 and the common wiring pattern 5 is avoided. Therefore, the reinforcing layer 10
And when the surface of the heating resistor 3 is covered with the protective glass 12, the surface portion of the heating resistor 3 is prevented from partially rising in the longitudinal direction.

According to this structure, since the reinforcing layer 10 is present at the other portion of the common wiring pattern 5, the voltage drop can be reduced and the reinforcing layer 10 can be reduced.
Due to the presence of the non-formed portion 11, the contact state between the print head and the platen becomes uniform over the entire printing width. As a result, the feeding action and the printing action with respect to the non-printed material such as thermal paper can be accurately performed.

The second to fourth embodiments of the present invention will be described below. In each of these embodiments, the same components as those of the first embodiment shown in FIG. Detailed description is omitted.

FIG. 3 shows a second embodiment of the present invention. On the back side of the heating resistor 3 and on the back side of the common wiring pattern 5 and the heat generation control individual electrode pattern 7, heat storage action is performed. Partial glaze 13 to improve transfer efficiency
Are formed. In this case, the common wiring reinforcing layer 10 is formed in a state where not only the interference portion 11 between the heating resistor 3 and the common wiring pattern 5 but also the location where the partial glaze 13 is disposed. Therefore, in this case as well, the thickness becomes uniform over the entire length of the heating resistor 3 in the longitudinal direction, and a partial bulge does not occur.

FIG. 4 shows a third embodiment of the present invention, in which a thin film reinforcing layer 14 is formed at a non-formed portion 11 of the common wiring reinforcing layer 10. The thin-film reinforcing layer 14 is formed using an inorganic gold paste, while other patterns are formed using an organic gold paste. As a result, in addition to suppressing a partial bulge in the longitudinal direction of the surface portion of the heat generating resistor 3, the occurrence of the phenomenon of the wiring pattern 5 being eaten by the heat generating resistor 3 is prevented, and the non-forming portion is not formed. The lack of current capacity due to the presence of 11 is compensated by the thin film reinforcing layer 14.

FIG. 5 shows a fourth embodiment of the present invention, in which a thin film reinforcing layer 14 is formed on the front side of the partial glaze 13 in the non-forming portion 11 of the common wiring reinforcing layer 10. The other constituents are the same as those of the second and third embodiments, and therefore the same effects as those can be obtained.

In the above embodiment, the invention of the present application is applied to a head substrate having a short width dimension used for a thermal print head for a tape writer, for example, as shown in the configuration example of FIG. A single drive IC 6 is arranged for one common wiring pattern 5.
However, in addition to this, the present invention is not limited to the above-mentioned Japanese Patent Laid-Open No.
As described in JP-A-84946, the present invention is similarly applicable to a head substrate of a type in which a plurality of drive ICs are arranged for one common wiring pattern 5.

In the above embodiment, the present invention is applied to the case where the common wiring pattern 5 straddles the end of the heating resistor 3, but the common wiring pattern 5 is the heating resistor 3. The present invention can be similarly applied to the case of passing near the end without interfering with the end. That is, by not forming the common wiring reinforcing layer 10 in the above-mentioned vicinity passing portion of the common wiring pattern 5, no bulge is generated in the portion along the longitudinal direction of the heating resistor 3.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration example of a thermal print head substrate according to a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional side view of an essential part taken along the line AA of FIG.

3 shows a thermal print head substrate according to a second embodiment of the invention of the present application, and is an enlarged vertical side view of an essential part corresponding to FIG.

FIG. 4 shows a thermal print head substrate according to a third embodiment of the invention of the present application, and is an enlarged vertical side view of an essential part corresponding to FIG.

5 shows a thermal print head substrate according to a fourth embodiment of the invention of the present application, and is an enlarged vertical side view of an essential part corresponding to FIG.

FIG. 6 is a schematic plan view of a main part for explaining a conventional problem.

FIG. 7 is a vertical cross-sectional front view taken along line BB in FIG.

FIG. 8 is a schematic plan view of a main part for explaining a conventional problem.

9 is a vertical sectional front view taken along the line CC of FIG.

[Explanation of symbols]

 1 Thermal Print Head Board 3 Heating Resistor 4 External Connection Terminal 5 Common Wiring Pattern 6 Drive Circuit (Drive IC) 7 Individual Electrode Pattern for Heat Generation Control 10 Common Wiring Reinforcement Layer 11 Non-Forming Location 13 Partial Glaze 14 Thin Film Reinforcement layer

Claims (3)

[Claims] 1. A heating resistor formed in a straight line from one end to the other end of the substrate, and a substrate width extending from the external connection terminal to the end of the heating resistor or passing near the end. Area extending between the heating resistor and the common wiring pattern that is routed to one side of the heating resistor after extending in the direction, and the arrangement portion of the drive circuit mounted on the other side of the heating resistor. And a heat generation control individual electrode pattern formed on the common wiring pattern, and a common wiring reinforcing layer is formed on the surface of the common wiring pattern. A thermal printhead substrate, characterized in that a non-formation portion of the common wiring reinforcing layer is present in a portion that crosses an end portion of a body or a portion that passes near the end portion. 2. The thermal printhead substrate according to claim 1, wherein the heating resistor is formed on the surface of the partial glaze. 3. The thermal print head according to claim 1, wherein a thin-film reinforcing layer made of a conductive metal, which is thinner than the common wiring reinforcing layer, is formed at a portion where the common wiring reinforcing layer is not formed. substrate.