JPS5959472A - thermal head - Google Patents

Abstract

PURPOSE:To extend the life of a thermal head determined by changes in the resistance value by arranging a heat generating resistor to be made up of a crystal part and a noncrystal part to hold the drop in the resistance value based on the crystalization of amorphous substance within the allowable list. CONSTITUTION:The surface of a substrate 1 made of alumina ceramic or the like is made flat to form a glaze layer 2 made of silicon dioxide or the like for a better heat storage. A thin film 3 comprising a silicon dioxide or the like is formed on the layer 2. Conventional methods are applicable for heat generating resistors 4a and 4b in the composition and production as for other parts. The lower layer 4a indicates an amorphous part and the upper layer 4b indicates a crystallized part. The position can be inverted in the crystal part and the noncrystallized part. The heat generating resistor of the thermal head is made up of a crystal part to hold the drop in the resistance value within the allowable limit based on the crystallization of the amorphous substance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal resistor that has a longer life determined by the resistance (li!T change) of the heating resistor. Alternatively, various types of additives such as alloys of silicon and other metals are used, but as they oxidize (C resistance value increases), they become unusable. Although the resistance change rate itself has been suppressed by oxidizing the heating resistor to a certain degree in advance, it cannot be said that it has a sufficient lifespan.

The reason why the resistance value increases due to oxidation is that the heating resistor is crystalline, and a typical example thereof is shown in the curve B of FIG. 2 attached. In other words, Curve 1 shows the heating time and resistance change rate of a sample prepared by using a substantially completely crystalline titanium silicide as a heating resistor and covering its surface with an oxidation-preventing film of silicon dioxide, heated to 500°C. The results of the Chiad test are as follows: for about 10 hours after the start of tenuto, no change in resistance was observed, probably due to the action of the antioxidant film, but after that, an increasing curve was drawn, and after about ioo hours had elapsed, the resistance value changed. It shows a change in resistance value of about 10 times. If the grain size of this sample is such that the permissible limit is a change in resistance value of a factor of 10, then the above-mentioned 100 hours would be the life of the sample. (
However, it cannot be said that it will respond perfectly when heating and cooling are repeated for short periods of time. ) The change in resistance value is largely due to not only oxidation but also the crystallinity of the heating resistor. Curve C in the attached FIG. 2 is a test result of a test sample made in the same manner as the above-mentioned sample, but with a substantially completely amorphous heating resistor under the same conditions as above.

The resistance value drops rapidly. This is because the titanium nose side changes from amorphous to thermally more stable crystalline.

Although it varies depending on various condition settings during use, in general, the rate of change in resistance value is greater due to crystallinity than due to oxidation. This is why crystalline heating resistors are generally used. but.

Oxidation and crystallinity exhibit resistance changes in opposite directions.

Therefore, if both oxidation and crystallinity are used, it will be possible to offset their negative effects.

The present invention has been made in view of the above-mentioned viewpoints.

The gist of the invention is to provide a thermal head comprising two heat-generating resistors on a heat-resistant insulating base material, an electrode for energizing the heat-generating resistors, and a protective layer, characterized in that the heat generation is within the above-mentioned range. It is used as a head.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the attached FIG. 1 will be described below.

In FIG. 1 (a), which somewhat schematically shows the vicinity of the selective heating section of a thin film type thermal head, reference numeral 1 is a base material made of alumina ceramics or the like.

A craze layer 2 made of silicon dioxide or the like is formed on the surface to flatten the surface and improve heat storage. A thin layer 5 made of silicon dioxide or the like is formed on the glaze layer 2 by a method such as sputter linking or other vapor deposition to prevent contamination due to impurities in the components forming the glaze layer. This thin layer 6 can also be considered as part of the glaze layer 2 and the base material 1. Glaze layer 2. Together, the thin layers 3 are commonly referred to as a heat-resistant insulating substrate. In addition to the above, heat-resistant insulating base materials that use glass or vitreous materials as at least the main element are well known. Reference numerals 4a and 4b are heating resistors, the details of which will be described later. Reference number 5 is gold and silver.

It is an electrode made of aluminum, tanksten, molybdenum, etc., which is coated by a method such as plating or sputtering, and then patterned by a method such as photorin, and formed into a single layer or multiple layers as appropriate. Reference number 6 is silicon dioxide, pentoxide p: /l /l/, ashing u! The protection M4 is made of silicon nitride, alumina, etc., and is appropriately formed into a single layer or multiple layers by a method such as sputter linking, and whose main purpose is at least wear resistance.

Now, explaining the 1 heating resistors 4a and 4b, the 0 heating resistors 4a and 4b are the same as the other parts.

Regarding the composition and fM method, basically the conventionally known compositions can be applied as they are. coated),
, l-1) It may be patterned using a method such as However, from the viewpoint of crystalline thermal stability at the temperature during use, silicides of high melting point metals are more preferable, and in addition to the aforementioned titanium and chromium, vanadium.

Zirconium, niobium, molybutin, ruthenium, rhodium, tantalum, tungsten,
Rhenium, osmium, iridium.

Gratina and the like are examples of high melting point metals. Further, as for the state, a crystalline portion and an amorphous portion must exist. Here, amorphous refers to a substance that can transform into a thermally stable crystalline substance, which causes a decrease in resistance value. 21114a and 4b in FIG. 1 are an example of this.

The lower layer 4a represents an amorphous portion, and the upper layer 4b represents a crystalline portion.

Of course, the positions of the crystalline portion and the amorphous portion may be reversed, or there may be more layers, or they may be completely mixed. The shape of these BVCs may be determined by taking into account the manufacturing method of the BVC and the ease of setting the resistance f1n. That is, the easiest way to make the two heating resistors crystalline or amorphous is to use the temperature during molding, which is easy to control. For example, if it is formed by vapor deposition, controlling the sample temperature low or high will make it amorphous or crystalline, respectively, and if the energy of the vapor deposited particles is used, the amorphous part will become the lower layer and the upper layer will become crystalline. Parts can be easily obtained. Similarly, if you raise the sample temperature in advance and then lower it midway through, the crystalline part will be in the lower layer and the amorphous part will be in the upper layer. However, it is generally difficult to control the temperature during FM manufacturing, and variations tend to occur when manufacturing in large numbers.Additionally, it should be noted that the aforementioned high-melting point metal silicide is ◇Curves A and A in the attached Figure 2 are examples of the structure shown in the attached Figure 1 using titanium silicide as the heating resistor. These are the test results. Titanium silica and Itozu were used to show the comparison with curves B and C mentioned above, and the test conditions were of course all the same except for the 9 heating resistor. The substrate 1 is made of alumina ceramics, the glaze layers 2 and 6 are made of silicon dioxide, the electrode 5 is made of molybdenum in the F layer, the upper layer is aluminum, the protective layer 6 is made of silicon dioxide in the lower layer, and the upper layer is silicon carbide. The formation of AIA took advantage of the difference in the post-formation state depending on the vapor deposition temperature. That is, AIA, B, and C were all formed by sputtering, but for A, the set temperature for the sample during sputtering was 400°C at the start and 520°C at the end. A' is the same as A, but 380°C at the start and 510°C at the end, 'C and D are 550°C and 350°C, respectively.
The zero curve l-, which was maintained at a constant temperature, showed a maximum resistance decrease of about 4 to 56 degrees, and then after about 650 hours, it decreased to about (g) 5.
% change in resistance value, and after about 460 hours it showed a change in resistance value of about (-1) 10%, and curve 2 A' showed a maximum decrease in resistance value of about 9 to 10%. rear.

After about 480 hours, a resistance value change of about (→5%) is shown, and after about 580 hours, a resistance value change of about 10% is shown. If the specifications set for the sample used are such that the resistance value change of ±5 is the permissible limit, then A~
Among C, A is the best, and if the resistance value change is ±10% as the permissible limit, A' is the best.

The tolerance limit for resistance change as a specification is set based on the results of various considerations such as recording paper and equipment, but in general, a culmability of ±5% or ±10 is well within the tolerable limit. Rather than keeping the maximum amount of resistance drop as small as, for example, 1 section, it is better to have a resistance value drop that is closer to the permissible limit set like curve A or A'. is highly preferred.

On the other hand, as can be seen from the comparison of two curves A and A'.

The maximum amount of resistance decrease is (-1-) 5% (→10
% of the resistance value change, that is, depending on the setting, it tends not to be proportional to life. In other words, doubling the resistance chain T (rate) does not double the lifespan. Considering the above-mentioned absolute extension of lifespan and the 411-year extension mentioned here, what is extremely effective is the "life span" which is determined based on the limit of sharpness when recording pictures, letters, etc. Rather than prolonging it for a long time, I would rather hold it back a little.

In addition, in order to have a sufficient effect of prolonging the life of a child, the wet large claw with a low resistance value should be at least a certain level.
In practice, specifically, it is set to about 3 or more "-1".

As mentioned above, in the thermal system of the present invention, the heating resistor is formed by joining the crystalline part and the amorphous part, and based on the crystallization of 31 quality, < t! Since the resistivity is kept within the permissible limits, the lifespan can be extended, and it can also be extended several times (C) compared to conventional crystalline heating resistors. That is.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts showing an embodiment of the present invention. FIG. 2 is a graph showing the relationship between heating time and resistance change rate for a sample. 1...Base material, 2...Glaze layer,
3. Thin layer. 4a, 4b...Heating resistor, 5...
···electrode. 6...Protective layer patent applicant Pentel Co., Ltd. (X) Banka I Sukae Hate Itouri Neichisho (spontaneous) Director-General of the National Intelligence Agency, Mr. Kazuo Wakasugi 1, Indication of matter f1 1982 Patent application No. 171158 Bow 2, name of the invention, Thermal Hen I. Relationship to the case Patent applicant Chi, Uiuku Nihonohano Furumicho Address 7-2-4 Nihonbashi Kokinumachi, Chuo-ku, Tokyo, Supplementary order Daily 6, contents of amendment (]) Line 1-1 of the sixth line from the second bottom of the specification says -Q resistance value j by l'l + J, but by 1 action it is 41 (anti-4fi J and +! I ' jE. (2) Specification t53 B, m 4 line 1'', 1rllll
'312 line # 1141115 line 11. 4916 It is written as ``1 crystallization in the right eye'' or ``1 crystallization in each eye''.

Claims (1)

[Claims] In a thermal head comprising two heating resistors on a heat-resistant insulating substrate, an electrode for energizing the heating resistors, and a protective layer, the heating resistor is formed by forming a crystalline part and an amorphous part. 71 - Resistance chain based on quality crystallization -
A thermal head characterized in that " is within the W1 permissible limit.