JP4766726B2 - Manufacturing method of thermal head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a thermal head incorporated as a printer mechanism such as a word processor or a facsimile.
[0002]
[Prior art]
In a conventional thermal head, a glass glaze layer is deposited in a strip shape on the upper surface of an insulating substrate made of alumina ceramic or the like, and a number of heating resistors are linearly formed on the glaze layer at a dot density of, for example, 300 dpi. deposition, have allowed to array structure, while conveying the recording medium of the thermal recording paper or the like on the heat generating resistor, individually selective based multiple heating resistor image data from the external the causes Joule heating, by conducting emitting heated heat on the recording medium, by forming a predetermined printing on a recording medium, and functions as a thermal head.
[0003]
Incidentally, the glaze layer by accumulating heat generated by the heating resistor is deposited on the upper surface, which is for maintaining a good thermal response characteristics of the thermal head, the glaze layer is given the glass paste by conventionally known screen printing is applied in a band on the upper surface of the insulating substrate, it is formed by baking it at high temperatures.
[0004]
[Problems to be solved by the invention]
However, in this conventional thermal head, when forming a glaze layer by screen printing or the like, the edge portion of the glass paste applied on the insulating substrate tends to rise significantly by the surface tension of the paste, the glass The shape of the glaze layer 12 formed by baking the paste also becomes a shape (A portion in the figure) with the end portion greatly raised as shown in FIG. When this kind of the glaze layer 12 conveys the recording medium on the heating elements 13 of the thermal head was Tsu lifting performing printing, the recording medium is other in the vicinity of the longitudinal end portions of the glaze layer 12 There was a drawback that uneven printing density was formed due to variations in sliding contact pressure that hit more strongly than the area.
[0005]
Further, when the edge portion of the glaze layer 12 is raised greatly as described above, at the time of printing, since the recording medium hits strongly to the protective film 14 is formed on the edge portion of the glaze layer 12, A large internal stress is generated in this portion, and the disadvantage that the protective film 14 is damaged in a relatively short period due to the stress is induced.
[0006]
[Means for Solving the Problems]
The thermal head manufacturing method of the present invention includes an insulating substrate, a convex glaze layer provided on the insulating substrate, and a plurality of heating resistors arranged on the convex glaze layer. A step of forming a convex glaze layer by applying a glass paste to the upper surface of the insulating substrate in a band shape and baking the same, and the convex glaze layer. Etching or blasting regions at both ends in the longitudinal direction, forming a height of the upper surface of the region lower than the central region and processing the central region into a raised shape, and the convex glaze layer And a step of disposing a plurality of heating resistors along the longitudinal direction.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Figure 1 is a plan view of a thermal head and manufacturing by the manufacturing method of the present invention, FIG. 2 is a sectional view taken along the line X-X in FIG. 1, 1 is an insulating substrate, 2 is a glaze layer, Reference numeral 4 denotes a heating resistor.
[0008]
The insulating substrate 1, alumina ceramics, which is formed in a rectangular shape by an electrically insulating material such as glass, glaze layer 2 above surface, the heating resistor 4, the individual electrodes 5, for supporting the common electrode 6, etc. Functions as a support base material.
[0009]
Moreover, the the upper surface of the insulating substrate 1, glaze layer 2 of the strip parallel to the long sides of the substrate 1 is adhered.
[0010]
The glaze layer 2, the low thermal conductivity material such as glass, are formed convex for forming Suyo, central region is in the form of raised than other regions.
[0011]
The glaze layer 2 accumulates heat generated by the heating resistor 4 deposited thereon to maintain a good thermal response characteristic of the thermal head, and causes the heating resistor 4 to protrude upward, so that Effectively increases the pressing force (printing pressure).
[0012]
At the center region of the glaze layer 2, for example, a large number of heating resistors 4 which are arranged linearly at a dot density of 300dpi is adhered.
[0013]
The heating resistor 4, each is TaSiO, TiSiO, since the consist electrical resistance material such as TiCSiO, causing a Joule heating when the supply power is supplied via the individual electrodes 5 and the common electrode 6 will be described later The predetermined temperature is required to form a print on the recording medium.
[0014]
Further, the both ends of the heating resistor 4, which is connected to the individual electrodes 5 and the common electrode 6, and cover them with a protective film 7.
[0015]
The individual electrodes 5 and the common electrode 6, which functions as a feeding electrode for applying power to the heating resistor 4, the individual electrodes 5, the switching elements of the driver IC not shown the end of the heating resistor 4 It is connected to the reference potential via Further, the common electrode 6 is connected to the other end of the heating resistor 4 to the power supply terminal of the positive (+) side of, for example, as to hold the potential of 24V.
[0016]
Meanwhile, the protective film 7, silicon nitride, made excellent inorganic material abrasion resistance and sealing properties of the sialon such as the heating resistor 4, by sliding contact of the individual electrodes 5, the recording medium and a common electrode 6, etc. It protects against corrosion caused by contact with water and moisture contained in the atmosphere.
[0017]
A thermal head described above, while conveying the recording medium of the thermal recording paper or the like on the heating resistor 4, by applying a predetermined electric power on the basis of image data from the outside between the individual electrodes 5 and the common electrode 6, the heating resistor 4 causes individually selectively joule heating, by conducting emitting heated heat on the recording medium, and functions as a thermal head by forming a predetermined printing on a recording medium.
[0018]
Next , a method for manufacturing the above-described thermal head will be described with reference to FIG.
[0019]
(1) First, as shown in FIG. 3A, an insulating substrate 1 made of alumina ceramics or the like is prepared.
[0020]
The insulating substrate 1, if made of alumina ceramics, alumina, silica, ceramic raw material powder in a suitable organic solvent magnesia, addition of a solvent, mixed with formed to mud漿状by which a well-known doctor blade method , by employing a calender roll method or the like, to obtain a ceramic green sheet, and thereafter, after punching the ceramic green sheet into a rectangular shape, are manufacturing by firing at a temperature of 1300 ° C. to 1600 ° C. The
[0021]
(2) Next, as shown in FIG. 3B, a convex glaze layer 2 ′ is formed in a strip shape on the upper surface of the insulating substrate 1 .
[0022]
The glaze layer 2 'and an appropriate organic solvent in the glass powder, addition of a solvent, conventionally known thick film technique a predetermined glass paste obtained by mixing, by specifically employing a screen printing, an insulating It was applied to the strip in the longitudinal direction of the substrate 1, which wears the by baking at a temperature of 1000 ° C. to 1200 ° C., are formed.
[0023]
Note that large bulges A due to the surface tension of the glass paste are formed at both ends of the glaze layer 2 ′ thus formed.
[0024]
(3) Next, as shown in FIG. 3 (c), a region from both ends to at least the inner 1.0mm in the longitudinal direction of etching or by blasting (blasting) of the glaze layer 2 ', the upper surface of the region of the height lower growth Succoth than the other areas, it is processed into a form that was raised central region. Incidentally, 'not only across regions in the longitudinal direction of the glaze layer 2' glaze layer 2 in this embodiment the entire peripheral area of the etching or by blasting, and it scraped.
[0025]
When employing etching to this process, firstly, a precursor of ultraviolet-curing resin is applied to the entire upper surface of the insulating substrate 1 glaze layer 2 'is formed by a roll coater or the like, then, ultraviolet curing The resin precursor is irradiated with an ultraviolet ray having a predetermined wavelength to a predetermined pattern corresponding to the shape of the raised portion 3 in the central region of the glaze layer 2 to partially cure the ultraviolet curable resin and develop an uncured portion. was removed by, thereafter, this was immersed in an etching solution containing hydrofluoric acid or the like to erode the ends region of the glaze layer 2 'chemically with the etching solution was, in the middle zone of the glaze layer 2 ridges 3 is formed, a large raised a that existed across regions of the glaze layer 2 'is removed at the same time.
[0026]
Also, in the case of employing the blasting step to depositing an ultraviolet curable resin in a predetermined pattern on the glaze layer 2 'is quite similar to that of etching the previously described, then immersed in an etchant silica filler in place of, performed by scraping off the alumina filler such as 'by ejection in the exposed portion of the glaze layer 2' glaze layer 2 physically to a predetermined depth from the surface.
[0027]
As a result, the height of the upper surface of both ends regions of etching or glaze layer scraped off by blasting is lower than other regions.
[0028]
Incidentally, the ultraviolet curable resin that is deposited on the raised portion 3 of the central region of the glaze layer 2, after this step, is peeled off the top of the glaze layer 2 by ultrasonic cleaning or the like.
[0029]
(4) Next, after applying a heat treatment to the glaze layer 2, as shown in FIG. 3 (d), depositing a large number of the heating resistor 4 on the ridges 3 of the glaze layer 2.
[0030]
The heat treatment, the individual electrodes 5, serving as a base glaze layer 2 that is the individual electrode 5 to smooth the surface of the common electrode 6 is for preventing breakage of the common electrode 6, for example, 900 ° C. C. to 1100 ° C. By heating at a temperature of 10 to 20 minutes.
[0031]
Further, the plurality of heating resistors 4 are conventionally known thin film techniques the electrical resistance material such as TaSiO, for example, sputtering, photolithography, employ an etching technique or the like, by processing in a predetermined pattern, the glaze layer 2 Are deposited and arranged in a straight line with a dot density of, for example, 300 dpi on the raised portion 3 in the central region of the first layer.
[0032]
(5) Finally, by connecting the individual electrodes 5 and the common electrode 6 at both ends of the heating resistor 4, is deposited a protective film 7 thereon.
[0033]
The individual electrode 5 and the common electrode 6 are deposited in a predetermined pattern by adopting a conventionally well-known thin film technique such as sputtering , photolithography technique, etching technique or the like by using a metal such as aluminum or copper.
[0034]
The formation, the protective film 7, the heating resistor 4, the individual electrodes 5, conventionally known sputtering silicon nitride or the like on the upper surface of such a common electrode 6, by plasma CVD or the like, by depositing a thickness of 3μm~10μm As a result, a thermal head as a product is completed.
[0035]
According to the manufacturing method of this embodiment as described above, by blasting etching or a region up to at least the inner 1.0mm from both ends in the longitudinal direction of the glaze layer 2 ', the height of the upper surface of the region other regions Therefore, when the heating resistor 4 is disposed on the raised portion 3 in the central area of the glaze layer 2 , large bulges of the glaze layer 2 are formed on both sides in the arrangement direction of the heating resistor 4. not Rukoto, during printing, and uniformly pressed by the recording medium for all of the heating resistors 4, it is possible to form a less satisfactory printing density unevenness.
[0036]
Further, according to this embodiment, as described above, by the absence large bulge like across regions of the glaze layer 2, sliding contact pressure also uniformity of the recording medium with respect to the protective film 7 formed on the glaze layer 2 Thus, it is possible to effectively prevent a large internal stress from being generated locally on the protective film 7 . Therefore, the protective film 7 can be applied to the base in a good state for a long time, and the reliability of the thermal head is greatly improved.
[0037]
Furthermore, according to this embodiment, when the as etching or the ends region of the glaze layer 2 above the scraped by blasting, the surface roughness of the region is of each component glass forming the glaze layer 2 contains the etching rate also due to differences in the neublastin Great, from becoming rough and 0.1μm~0.5μm center line average roughness (Ra), when was deposited a protective layer 7 thereon, the base The adhesion strength of the protective film 7 to the surface is improved by the anchor effect, and the reliability of the thermal head is improved.
[0038]
In addition, this invention is not limited to the above-mentioned form, A various change and improvement are possible in the range which does not deviate from the summary of this invention.
[0039]
For example, although the heating resistor 4 and the individual electrodes 5 and the common electrode 6 are formed in separate steps in the above-described form, they may be formed in the same step.
[0040]
【The invention's effect】
According to the present invention, heating the region of both ends in the longitudinal direction of the glaze layer etching or by blasting, the height of the upper surface of this region since it was lower than the central region, the central region of the glaze layer when the resistor is disposed, not a large swelling of the glaze layer is formed on both sides in the arrangement direction of the heating resistor, during printing, and uniformly pressed by the recording medium for all of the heating resistors Therefore, it is possible to form a good print with little density unevenness .
[Brief description of the drawings]
FIG. 1 is a plan view of a thermal head manufactured by a manufacturing method of the present invention.
FIG. 2 is a cross-sectional view taken along line XX in FIG.
FIG. 3 is a cross-sectional view for each step for explaining the manufacturing method of the present invention.
FIG. 4 is a partially enlarged sectional view of a conventional thermal head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulating substrate, 2 ... Glaze layer, 3 ... Convex part, 4 ... Heat generating resistor, 5 ... Individual electrode, 6 ... Common electrode, 7 ... Protective film

Claims (2)

A method of manufacturing a thermal head, comprising: an insulating substrate; a convex glaze layer provided on the insulating substrate; and a plurality of heating resistors arranged on the convex glaze layer. ,
Applying a glass paste in a band shape on the upper surface of the insulating substrate and baking the same to form the convex glaze layer;
Etching or blasting the regions at both ends in the longitudinal direction of the convex glaze layer, forming the height of the upper surface of the region lower than the central region, and processing the central region into a raised shape, and
And a step of disposing a plurality of heating resistors along the longitudinal direction on a central region of the convex glaze layer.   The surface of the convex glaze layer is smoothed by heat-treating the convex glaze layer after processing the central area of the convex glaze layer into a raised shape. 2. A method for producing a thermal head according to 1.

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