JPS60236767A - Thermal printing head - Google Patents

Abstract

PURPOSE:To provide a thermal head which can hold the optimum printing density with a simple construction by forming a common electrode electrically connected to individual heating resistor elements on the main surface a driving base body on which a resistance base body having a heating resistor element train is placed. CONSTITUTION:A driving circuit 2 and a signal wire 24 for driving it are provided on a ceramic driving substrate 11, both connected with a wire bonding line 21. A common electrode 3 is formed on the main surface of the driving substrate 11 on which a resistance substrate 12 is to be placed and then, the resistance substrate 12 is placed thereon through a bonding member. A plurality of heating resistor elements 1 are arranged on the main surface of the resistance substrate 12 and connected to the second common electrode 40 with a conductor wire.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal printing head C2 used in facsimiles and the like.

[Technical background of the invention and its problems]

In recent years, Kando Arl Record has become known as one of the recording methods used in facsimile machines, printers, etc., and the seventh recording part is called a thermal printing head.

Thermal printing/printing head is the name of the electrical-thermal conversion output section used in thermal EtJ.

General I: Thermal printing heads are manufactured using high-resistance, heat-resistant base materials such as alumina and steatite, and manufacturing techniques such as thick films, thin films, and semiconductor materials to produce heat-generating resistor elements and heat-generating resistor elements. A drive circuit for driving the electrically connected heating resistor element and a common electrode electrically connected to the other end of the heating resistor element are formed.

In a thermal printing head, when two heating resistor elements partially generate heat, voltage drop becomes a serious problem.

However, when the printing density is high, for example when 16 heating resistor elements are arranged in one width, the voltage drop due to the width and film thickness of the common electrode will have a negative effect on the printing density, and the printing density will become extremely high. Negative effects such as thinning occur. Therefore, in the past, the width of the common electrode was widened, the common electrode was externally attached with a metal with low resistivity such as copper, or the common electrode was formed with a material with low resistivity and the film thickness was thickened to reduce the pressure drop. Efforts have been made to reduce it. However, this did not provide a fundamental solution as the number of parts and manufacturing processes increased.

In order to solve the above-mentioned problems, the present inventors
The heating element part disclosed in Japanese Patent No. 4-139558 is formed of a thin film substrate using thin film technology, and the common lead multilayer wiring part (
We tested a dual printing head in which the driver multilayer wiring part was formed using a thick film substrate using thick film technology, and found that the thickness and width of the common electrode were sufficient. If it were to be made smaller, the size of the thermal printing head would be very large, which is contrary to the trend of technology to miniaturize thermal printing heads.

In other words, the smaller the thermal grid/ting head that can be incorporated into a facsimile machine, the better, but the thermal grid/ting head disclosed in JP-A-54-139558 C has the risk of becoming large. There is.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a thermal printing head that has a simple structure and is capable of maintaining optimal print density.

[Invention (L required)]

In order to achieve the above object, the present invention forms a common electrode electrically connected to each photothermal resistor element C on the main surface of a drive base on which a resistor base on which a row of heat generating resistor elements is shaped is mounted. Since this is a thermal grating head that is characterized by the following, it is possible to obtain optimal print density with a small size.

[Embodiments of the invention]

Next, the thermal printing head of the present invention will be explained with reference to the drawings.

In FIGS. 1 and 2 C', a drive board (11) made of ceramic is placed on a heat dissipation board 6Q made of ceramic via an adhesive member (not shown). A drive circuit, for example, an IC (2), etc., is placed on the drive board αυ. This IC (No. 4> wiring (2(a) that drives 2+)
are formed using thick film technology. This signal wiring (goods)
and IC12) are electrically tangential to each other by a wire bonding line Qυ made of gold or aluminum. On the other hand, the drive board (on which the resistor board (12+) is placed)
II) has a resistive substrate (121
The area of the first common electrode (3) is equal to or greater than (2)
, ) is formed. C on this first common electrode (3)
The resistor substrate a is attached via an adhesive member (not shown) such as silicone resin. A plurality of heating resistor elements (1) are arranged on the main surface of this resistor substrate (1). Each heating resistor element (1) is connected to a second common electrode (4) by a first conductor wiring (not shown). The extending second conductor wiring (not shown) is electrically connected to the filc (2) by a wire bonding wire (2λ) made of gold. The second common electrode (40) is electrically connected to the conductive substrate (2) provided at the end of the resistor substrate.The power terminal is provided to the first common electrode (3). , Ql is a platen roller that feeds the thermal paper (to).

The thermal printing head shown in Figs. 1 and 2 uses thick film technology when forming the drive substrate (signal wiring).
24) and simultaneously formed the l-th co-tracing pole (3). Therefore, the width of the second common electrode on the resistive substrate other than the power terminal portion can be reduced, and as a result, the thermal printing head can be made smaller. However, since most of the common electrode was formed during the formation of the drive board, when a large current flows, the concentration unevenness occurs due to a heavy pressure drop on the common electrode, especially due to the high density of the heating resistor element. The danger of unevenness is avoided. Furthermore, since the first common rectangle and the pole (3) form a shadow covering the resistive substrate (41), the voltage drop across the entire common electrode will be reduced if the first common electrode (3) is damaged. Any danger that may arise is also prevented. Furthermore, by using a copper plate or the like as the first common electrode (3), an inexpensive thermal printing head can be provided. It's obvious that it's good.

The means for electrically connecting the first common electrode (3) and the second common electrode side of the thermal printing head of the present invention includes:
The above-mentioned conductor substrate C is not limited to two. For example, a flexible tape and a resistance board (lz7 +:: through hole may be provided, and electrical connection may be made via a conductor inserted into the through hole.

Although the resistance board 0.21 and the drive board (11) were bonded together via the adhesive part q (not shown), the present invention is not limited to this, and for example, the resistance board 0.21 and the drive board (11) may be It may be fixed using, etc. At this time, the clamp member,
The first
It goes without saying that the electrical connection between the common electrode (3) and the second common electrode (401) is good.

Next, referring to FIG. 3, the circuit structure of the thermal printing head of the present invention will be briefly described.

In FIG. 3, a heating resistor element (1) for generating Joule heat and giving recording energy to a thermosensitive recording class;
A common electrode (3) connected to one end of this heating resistor element (1), and a driver IC (2) for driving this heating resistor element (1) at the other end of this heating resistor element (1).
! = Blank, the thermal printing head is configured. The thermal printing head of the present invention has a resistive substrate and a driving substrate separated.

The division is usually performed between the terminals (8)'+f9j shown in FIG. 3, and after joining, the terminals (81, (9) are electrically connected via wire bonding lines (2).

In addition, (4), (51, and (6) are IC (21
Each signal group controls the Further, the embodiment of the present invention is I
Although the description has been made using a C tower type thermal printing head, the present invention is not limited to this, and may be applied to a diode matrix type thermal printing head.

〔Effect of the invention〕

By adopting the above-described configuration, the thermal printing head of the present invention can be miniaturized because the common type square electrode provided on the resistive substrate can be eliminated. Furthermore, since the thermal printing head of the present invention can form a common electrode with sufficient width and thickness, it is possible to prevent the voltage from being blocked by the common electrode, so that the average printing density can be changed.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing an embodiment of the thermal printing head of the present invention, Fig. 2 is an enlarged partially cutaway plan view of the main part of Fig. 1, and Fig. h33 is a schematic diagram showing the circuit configuration of Fig. 1. be. (1)... Heating resistor element (3)... First common electrode aυ... Drive board α'IJ... Resistance board (2)... IC (drive circuit) (24)... ...Signal wiring (drive circuit) (40) ...Second common electrode (41) ...Conductor substrate Agent Patent attorney Kensuke Norichika (1 person) Figure 1

Claims (1)

[Claims] (1) A resistance base including a plurality of heat generating resistor elements on a first high resistance base material, and a drive circuit electrically connected to the heat generating resistor elements on a second high resistance base material. A thermal printing head comprising a drive base having a 1.0 mm diameter, wherein the resistance base is placed on the drive base, and the low resistance base is mounted on the drive base.