JPS6189601A - Protective film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an abrasion-resistant protective film, and particularly to an abrasion-resistant protective film for a thermal head.

[Conventional technology] □ The thermal head of the JE thermal printer, which is conventionally used as one of the output methods for facsimiles, computer terminals, word processors, recorders, etc., basically prints on the surface as shown in Figure 81. A resistive heating element layer 2 is formed on the surface of a ceramic substrate 1 having a heat storage glaze layer. b% with a lead layer 3.3' provided at both ends for electrical conduction.
As an upper layer 1, to prevent wear and damage of the heating element layer 2 and lead layer 5.3 # due to sliding contact with thermal paper - protection layer 4
will be established. In use, when electricity is applied between the lead layers 3 and 31, the resistance heating layer 2 generates heat, and the heat is applied to the thermal paper through the protective layer 4 to perform thermal recording ◇ and to prevent heat generation over a long period of time. 4J is required to be able to fully demonstrate its functions.

There is no satisfactory material for the protective layer that can meet such severe conditions. The materials traditionally used are Thos and SiC, but 'ragos is resistant to hardness! l! Inferior in terms of wear resistance. Although SLC has high hardness, it lacks toughness and has low cooking resistance. Also 8 10.
has been considered, but it may react with thermal paper or
It is not used because it has a high printing coefficient with 6-optical paper and causes problems such as sticking.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an abrasion-resistant and 11-inch to 2-side cracking membrane. Another object of the present invention is to provide a protective film having the above-mentioned excellent properties, especially for thermal heads.

[Practice of invention]

The protective film of the present invention has a composition S10 (where x'+0,
y' (0, X/y=C1,01-10).

The protective film of the present invention has high heat resistance and wear resistance, and has a sufficiently high iF1 compared to conventional 'ra, o.
In addition to being wear-resistant, it has no reactivity with paper like Sin, and does not cause cranking even when subjected to thermal stress caused by repeated pulsed energization.

[Detailed description of the invention]

The present invention will be explained in detail below. FIG. 1 shows a heating element part of a thermal head according to an embodiment of the present invention.
1 is an alumina substrate with a glaze layer, 2 is α2μrn
3. thick polySi quinary compound thin film resistor layer;
3' is 2 pml! 2 is Au1 Yuzu, 4 is 3pm8 5iO
xB (however, x S Oly, 4°) is a thin film.

The protective film of the present invention is a compound represented by A from S10,
x/y=α01~1. O(x, yNO) T ant,
Preferably x/y = 0.1~'LO
When x/y is less than α01, the crank strength is low. X/
As y increases, the wear rate increases, but if x/y is less than 1, the wear rate is still sufficiently small compared to 'ratos, so there is no problem, and the crank strength becomes very high. x
/ When y exceeds 1, the reactivity and sticking
You can see the horizon. Note that when X is less than α01, conductivity occurs, resulting in the inconvenience of having to add an insulating layer between the heat generating layer and the heat generating layer. The effect of 1%7 on Sl is that if x and y become too large relative to SM in terms of atomic ratio, the crack strength and wear rate will decrease, so the following concavity and convexity is ideal as a straight line of process and y.

α05−xSy≦1 Examples of the present invention will be described in detail below. The protective film of the present invention can be formed by vapor phase epitaxy (plasma CVD), sputtering, etc., but preferably the former is used.

100μm×′ by parallel plate plasma CVD method
A film was formed on a 500 pm base device (see FIG. 1). That is, using Ha and Hl as carriers and 20% SiH as the source.

/ He 200 SCCM, 5%B! H6/H
, 50 to 50 Q 5CCK (variable) and N, O to Q
, ISCCM ~ 10 SCCM (variable) flow rate,
Temperature 550゛C1 Pressure 0.2 Torrs and Input 200
Film formation was performed under W conditions. Printing elements (dots) for thermal heads having a-retaining films of various compositions thus obtained
A test was conducted on the following.

Generally, a step stress test is an easy way to determine the crack resistance of a thermal head. In this method, the resistance change of the heating resistor is measured while gradually increasing the voltage applied to the heating resistor for a certain period of time. Is the protection theory a good thing? evaluate. The following 11 methods were used for the test.
It is one.

That is, the scanning line printing time is 10 maee or more, the number of scanning line divisions is B48, the data transfer frequency is 1 MH2°, the data feed is 248 (B4M8), and the printing voltage is iEL.

~ 2tov is $20% and mileage is 30 Km. The dimensions of the heating resistor are width 130μm and length 280μm.
It is.

In the step stress test, the crack strength is defined as the mark 7M power (watts/dot) per heating resistor where the crank occurs. In addition, when the recording paper is run with the immediate force at the maximum printing b5 degree, one shift (μ
m/Km) is taken as 4 ratios.

The second threshold is 5iOB
This figure shows the dependence of the wear rate and crack strength on the composition ratio x/y of the thermal head shown in FIG. 1 using r'M and y. The crank strength improves rapidly with the value of x/y. The wear rate tends to increase, but when x/y<tO, the wear rate is smaller than that of conventional Ta and OB.

As described above, the protective film of the present invention has excellent wear resistance, sufficient rigid crack resistance, is chemically stable, and can provide a thermal head with high longevity and reliability.

[Brief explanation of drawings]

Figure 1 is a sectional view showing the structure of the thermal head, and
The figure is a graph showing the influence of the component ratio of the protective film on its characteristics. 5゜

Claims (1)

[Claims] 1. A wear-resistant protective film made of a compound having the composition SiO_xB_y (where x≠0, y≠0, and x/y=0.01 to 1.0). 2. The protective film according to item 1 above, wherein x is 0.05 to 1.0 with respect to Si1 in terms of atomic ratio.