JPS6292860A - Thermal head - Google Patents

Abstract

PURPOSE:To increase the quantity of heat flowing to the side of a thermal recording paper and ensures adaptability to the use of a rough paper, by sequentially providing a glaze glass, a TiO2 layer 0.01-1mum in thickness, a heating resistor layer, an electrode film and an abrasion-resistant protective film on an insulating substrate. CONSTITUTION:A glaze glass 2, a TiO2 layer 7 of 2,500Angstrom thickness, a Ta2N thin-film resistor layer 3 of 0.2mum thickness, W electrodes 4 of 1mum thickness, an SiO2 anti-oxidizing layer 5 of 1mum thickness and a Ta2O5 layer (abrasion- resistant protective layer) 6 of 4mum thickness are provided on an insulating substrate 1 to produce a thermal head. The TiO2 layer 7 and the thin-film resistor layer 3 are provided by sputtering. Accordingly, since the TiO2 layer 7 having a high thermal reflectance is provided between the glaze glass 2 and the thin-film resistor layer 3, the quantity of heat flowing to the side of a thermal recording paper is increased, whereby energy density is enhance, and the thermal head can be used for recording on a rough paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head used for heat-sensitive or thermal transfer recording, and particularly to a thin-film type thermal head.

[Summary of invention O]

The present invention improves energy efficiency and enables printing on so-called rough paper by forming a To02 layer with high thermal O reflectance between an insulating substrate and a heating resistor layer in a thermal head. .

[Conventional technology]

There are two types of thermal heads: thick type and thin film type, and each type has become popular due to its characteristics.However, in recent years, as print quality has become more sophisticated and the need for calibration has increased, thin film types, which are capable of high fluctuations and changes, have become mainstream.

Generally, a thin film type thermal head has a glaze glass 2 formed on an insulating substrate 1 as shown in Fig. 2, and further includes a heating resistor 3 and a base 4 for energizing it. It is formed of an acid and abrasion prevention film 5 and an abrasion-resistant protective film 6 to prevent acid and abrasion from occurring on the heating resistor.

The heat-generating resistor can withstand pulsed energization, generates heat only by coloring the thermal paper or melting the ink on the transfer paper, and can be safely cooled down quickly before the next pulsed power is applied. ■Materials that meet this requirement include Ta2N, T
A thin film such as cLsio2 is used. An Or-A1L film, a W film, or the like is used as the electric cross film that passes through this heating resistor layer. To prevent damage, SiO2
Tc is mainly used as an abrasion-resistant protective film.
LzOs * 5ZCI SZ3”4, etc. ■Hard thin film is used 1 As shown in Figure 2, when a pulse voltage is applied to the heating resistor and a current flows, the resistor generates heat.The heat flow becomes QP, which improves wear resistance. There is a part that passes through the heat-resistant film layer to the thermal recording paper side, a part that becomes the heat flow QB and goes to the substrate side, and a heat flow QSO3 that goes to the dot part next to the voltage and continuous abrasion-resistant layer.Generally, In the case of a head dot using a glazed glass/alumina substrate, QP is approximately 20%, QB is approximately 40%, and QS is approximately 40.
%■'1 Heat flow is distributed at the ilJ meeting.

[Problems and objectives to be solved by the invention] However, conventional p-thermal printers are definitely inferior to impact-type printers in that they produce so-called rough paper. Although it has the advantage of silent recording, the biggest reason why it is not possible to use so-called rough paper for IAl as a replacement for impact type printers is that it maintains durability. This is because it is not possible to obtain a sufficient energy density.

Therefore, the present invention solves the conventional problems such as:
TiO with high heat reflectivity is used between the insulating substrate and the heating resistor layer.
By changing 21- to form 531:, the heat flow QPO toward the heat-generating recording paper side is increased, thereby increasing the energy density and making it possible to create a thermal head that can handle rough paper. The purpose is to provide.

[O means to solve the problem]

The thermal head of the present invention includes an insulating substrate and a heating resistor j-
It is assumed that during this period, a thermal O reflectance of 0 and a high Vh TzLl 2 + scratch was formed.

The thickness of the Tz(J) layer is limited to between 100χ and lμO.The reason for this limitation is that cracks tend to occur when the TiO20 thickness exceeds 1μ, and the heat flow QB toward the substrate side
O heating device becomes considerably smaller. As a result, in the case of continuous recording, heat is accumulated in the vicinity of the heating dots, causing a trailing phenomenon in the print, so the thermal film QBIj cannot be made smaller unnecessarily. The basics are point 2. If the film thickness exceeds 1 μm, the applied power can be satisfied with a small amount, but problems will occur in terms of thermal response, which will have a negative impact on high speed and high printing quality.
The film thickness of the primary TzO2jd that affects 81% is %100A.
The thickness of the TiO2 layer in the present invention is too
X~1μ is required, but preferably 200~xooo
The film thickness is X.

In Table 1, A, /! ,,03. Tz'02. From the 16th, showing the coefficient of thermal expansion, thermal conductivity, and drowsiness resistance of A
7'103, TiO2 both show the same coefficient of thermal expansion as vinegar. When the thermal head reaches a light temperature,
Breakdown between the insulating substrate and the layer due to the difference in thermal expansion Q is unthinkable.

Mr. @1 (comparison of various notes) Next, the present invention will be explained according to the embodiments.

[Implementation row]

FIG. 1 shows the vicinity of the heating element of a thermal head according to an embodiment of the present invention. l is an insulating substrate 7t1500
Al9jO'h:021'J, 2tf crease, 3
TiO, 7.2NO thin film resistive layer with 21J/rIL thickness,
4ttl nm1j2) Wt Hidden 5 is 1μm thick +Bo,
The antioxidant layer 6 is a 4 μm thick Ta205 layer and is an abrasion-resistant protective layer.

Tz'O, Id and the thin film resistance layer are formed by sputtering.
The shape of the heating element was formed using photoringraph technology.

Etching is performed by dry etching two layers, the TAU layer and the thin film resistor j-, at the same time, and the TiO2 layer has the same shape as the upper thin film resistor layer. The W voltage was formed by a vapor deposition method, and an electric picture shape was also formed using photolithography. The anti-oxidation layer and the abrasion-resistant protective layer were formed by sputtering.

The sputtering conditions for the TzO2 layer in this example are as follows. Substrate temperature 250℃, Ar partial pressure 5.5×10-”
TO? In this sputtering, a deposition rate of 100 A/win G was obtained under the conditions of 2 A and 360 V.

As a column for comparing the V)% properties of the thermal head according to this embodiment, a general thermal spatula with a structure as shown in Fig. 2 is used! ! Built. 1 is an insulating substrate, 2 is glazed glass, 3 is a 0.2 μm thick Ta2B1 thin film resistance layer, 4
is 2 μm thick wtff;, 5 is 1 μm thick sho, ■
Antioxidant@, 6 is an abrasion-resistant protective film of 'I'cLzOs with a thickness of 10μ. For the thermal heads of Examples and Comparative Examples, a printing test was conducted using a thermal transfer method on rough paper with a smoothness of 5 seconds. From the results in Table 3, Table 2 shows the printing test conditions, Table 3 shows the applied power until printing is possible, and the number of pulses until cracks occur in the abrasion-resistant protective film when driven under those conditions. The thermal head according to the present invention has sufficient durability even when printing on rough paper with a smoothness of 5 seconds.

From the results in Table 2 (printing test conditions) and Table 3 (applied power and crack occurrence status),
There is a large difference in durability between the thermal head according to the present invention and the conventional thermal head. The applied power for printing on rough paper for 5 seconds is 1.5W/
If the dots are too high, cracks will easily occur, and heat dissipation is poor, so-called trailing will occur during printing, making it virtually impossible to print on rough paper.

Next, using the above 7) 2 Hidden O to Rad, the smoothness is 20
Table 4 shows the maximum printing speed when kanji are printed on 0 seconds 0 printing paper using the thermal transfer method.

Table 4 (Maximum printing speed) In this implementation, we were able to achieve a printing speed that far exceeds that of conventional thermal heads.

In this example, the film thickness of TzO21 was set to 50OA, but this film thickness is the most suitable film thickness that satisfies these two conditions from the viewpoint of thermal response and small applied power. 1 In the present invention, the film thickness of the GD Tjo two layers is 1o
Although printing is possible in the range of ox to 1 μm, the Ti port 21
If the film thickness of - is less than 100λ, the heat reflection effect will be small with the film thickness of .
0At- exceedance is required. Furthermore, when T6o and layer thickness exceed 51mm, the applied power is satisfactory, but so-called tailing phenomenon occurs, which deteriorates thermal response and is detrimental to high speed and high printing quality. Casts a shadow #j/.

Tho 1 layer 0 film IIL is above ■For reasons, 1005~
A film thickness of 1 μm is required, preferably 200A to 10
The thickness is 00A■.

[Invention ■ Effect]

As explained above, the present invention provides the following effects by incorporating the IATi02 layer with high heat reflectance between the insulating substrate and the heat generating resistor layer.

←) Energy efficiency has improved, making O printing possible on low-slip paper with low energy consumption.

(b) Energy density has increased, allowing high-speed printing.

(c) Energy efficiency is good, and since the power applied through the heating element requires low energy, the material is not subjected to stress, resulting in improved material durability and high strength.

[Brief explanation of drawings]

Figure 1 is a sectional view of the vicinity of the heating resistor of the thermal head of the present invention, and Figure 2 is a sectional view of the vicinity of the heating resistor of the conventional thermal head. l...#? 2R note board 2-...Glaze glass 3...Heating resistor 4...Electrode 5...Anti-oxidation film 6...Abrasion resistance 7...Tio 2 layers or more

Claims (1)

[Claims] In a thermal head that has a glaze glass, a heating resistor layer, an electrode film for supplying electricity to this on an insulating substrate, and an abrasion-resistant protective film formed thereon, the glaze glass and the heating resistor layer are TiO with a thickness of 0.01 to 1 μm between
A thermal head characterized by forming two layers.