JPH0439067A - Thermal printing head - Google Patents

Abstract

PURPOSE:To easily position a thin-film heating resistor layer to electrodes to perform an efficient production by a method wherein the electrodes are disposed across a projected insulating layer provided on a substrate, and the thin-film heating resistor layer is formed in a belt form on the projected insulating layer in an electrode aligning direction so as to connect to the electrodes at the both skirt parts beyond said insulating layer. CONSTITUTION:On a film substrate 10, a selection electrode 11 and a common electrode 12 are patterned. Ni and Au are laminated to form a metal layer. A resist is patterned on the metal layer. The metal layer is masked by the resist to be etched for removing an unnecessary part. Then, the selection electrode 11 and the common electrode 12 made of the metal layer are formed in a staggered form. After that, an adhesive 17 is applied between end parts 13, 14 opposed to the selection electrode 11 and the common electrode 12. A fiber 16 is bonded on the film substrate 10. The adhesive 17 is intruded between the periphery of the fiber 16 and the end parts 13, 14. After that, the adhesive 17 is dried, and a thin-film heating resistor layer 18 is formed on the fiber 16. In this manner, the thin-film heating resistor layer 18 is formed beyond the fiber 16 with the both ends thereof connected to the end parts 13, 14 of the electrodes 11, 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal print head that performs thermal printing.

The structures shown in Fig. 8 and 8 are known. This thermal print head uses a ceramic substrate using thin film molding technology.
A raised part 2 is formed on the raised part 2, and a large number of thin film heat generating resistive layers 3 extending over the raised part 2 and extending on both sides are arranged at equal intervals, and selection electrodes are arranged facing each other with each thin film heating resistive layer 3 in between. 4 and a common electrode 5 are formed, the selection electrode 4 is connected to one end side of each thin film heating resistance layer 3, the common electrode 5 is connected to the other end side, and the upper surfaces of these are covered with an insulating material 6. It has a similar structure.

In this thermal print head, when a printing current is selectively supplied to the selection electrode 4, the current flows through the thin film heat generating resistor layer 3, which selectively generates heat, and this heat is used to perform thermal printing. . In this case, since the heat generating portion of the thin film heat generating resistor layer 3 is protruded from other portions by the raised portion 2,
The heat-generating part hits the paper well, allowing for clear printing.

[Prior Art] Conventionally, as a thermal print head, as shown in FIG. Therefore, when a higher density of printed dots is required, the spacing between the thin film heat generating resistor layers 3 becomes finer, so a highly accurate technique is required to form the thin film heat generating resistor layer 3. Ru. Moreover, in the thermal print head described above, the ends of the selection electrode 4 and the common electrode 5 must be overlapped on both ends of each thin film heat generating resistor layer 3, which makes it difficult to align when forming each electrode 4.5. , which requires high precision and is inefficient.

In order to solve the above-mentioned problem, select electrodes and common electrodes are arranged alternately on the substrate in advance, and a heat-generating resistive layer such as conductive ink is printed on these electrodes along the direction of arrangement to create a thick film. A band-shaped thermal print head is being considered. However, with this thermal print head,
Since the thickness of the heating resistor layer is thick, there is a large variation in the resistance value.Moreover, the heating resistor layer between the electrodes, which is the heating part, is formed low, and the heating resistive layer on the electrode is formed high. There is a problem in that the contact surface that comes into contact does not become a -like flat surface, and printing quality deteriorates with high-density dots.

An object of the present invention is to provide a thermal print head in which the shape of the thin film heating resistor layer is simple, does not require sophisticated manufacturing technology, and can be easily aligned with the electrodes, and can be manufactured efficiently. It is.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a protruding insulating layer on a substrate, and arranges electrodes on both sides of the protruding insulating layer to sandwich the protruding insulating layer. A thin film heat generating resistor layer is formed in a band shape along the arrangement direction of the electrodes on the shaped insulating layer and connected to the electrodes at the skirts on both sides thereof.

[Function] According to the present invention, the thin film heating resistor layer is connected to each electrode arranged on both sides of the protruding insulating layer on both sides of the protruding insulating layer by climbing over the protruding insulating layer and being connected at the base portions on both sides of the protruding insulating layer. Since the electrodes are formed in a band shape along the direction in which the electrodes are arranged, even if the spacing between the heat generating parts becomes finer, there is no need to separate the heat generating parts of the thin film heat generating resistor layer.Therefore, the thin film heat generating resistor layer can be easily formed. This makes it possible to extremely easily align the thin film heat generating resistor layer on each electrode, and to efficiently produce the thin film heat generating resistor layer.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

1 and 2 show the main parts of a thermal print head. In these figures, IO is a film substrate. This film substrate 1O is made of synthetic resin such as polyimide. On its upper surface, a large number of selection electrodes 11 and common electrodes 12 are arranged facing each other and spaced apart from each other over the entire area in the width direction (four electrodes are shown in each figure, but there are actually many selection electrodes 12).
The selection electrode 11 and the common electrode 12 are made of Cu or A1. Alternatively, it is made of a single or multi-layer metal layer with plating of i, ^U, etc. on its surface, and by forming the film to be relatively thick, about 10 gm, as described later, the radius can be increased to 3.
Even when the distance is as small as 0 to 704 m, it is possible to conduct a large current. In this case, as shown in FIG.
For example, if it is 16 dots) / mm, it is 82.5gm
They are arranged in parallel at a certain interval, and the respective ends 13 on the common electrode 12 side are aligned in a straight line. The common electrode 12 is formed into a comb shape. That is, selection electrode ll
One end 14 of the side is formed in the same shape as the selection electrode 11.
They are arranged in a so-called zigzag pattern, spaced apart from each end 13 of the selection electrode 11 by a predetermined interval, and alternately shifted in the arrangement direction. Further, the other end portion 15 of the common electrode 12 is formed in a wide band shape along the arrangement direction of the one end portion 14 described above,
Each end 14 is connected.

As shown in FIG. 1, a fiber 16 is arranged between the selection electrode 11 and the common electrode 12, which are bonded to the film substrate 10 with an adhesive 17.
This fiber 16 is a linear material made of glass, quartz, resin, etc., and may or may not be transparent.
has a thickness of approximately 50 gm, and is provided so as to protrude above the upper surface of each electrode 11, 12. The adhesive 17 is preferably made of polyimide, which has good reliability against thermal stress, but is not limited thereto.

Further, a thin film heat generating resistance layer 18 is provided on the fiber 16 at the electrode 1.
1.12 are provided in a band shape along the arrangement direction. That is, the thin film heating resistance layer 18 is.

It is formed into a band shape with a width wider than the width between the opposing electrodes 11 and 12, and extends over the fiber 16, and both ends thereof are connected to the selection electrode 11.
and one end 14 of the common electrode 12 and are connected to each other. This thin film heat generating resistor layer 18 has a thickness of T
It is made of tantalum nitride such as a2N and has a thin film thickness of about 1000λ.A protective layer 19 is provided on the upper surface of these.This protective layer 19 is made of Si0
Although it has a two-layer structure consisting of a moisture-resistant protective film 20 such as No. 2 and a wear-resistant protective film 21 such as Ta205, it may have a single-layer structure.

Although not shown in the figure, each selection electrode 1 is provided on the film substrate IO.
A drive transistor that selectively supplies a printing current to the drive transistor 1, a control element that controls the drive transistor, and the like are integrally provided.

Next, the manufacturing process of the above-mentioned thermal print head will be explained with reference to FIGS. W43 to 6.

First, as shown in FIG. 3, a selection electrode 11 and a common electrode 12 are patterned on a film substrate IO. That is, Cr is deposited on the film substrate IO by vacuum evaporation or sputtering, Cu is laminated thereon by electrolytic plating, and then Xi and Au are laminated thereon in sequence by electrolytic plating. As a result, a metal layer having a thickness of about 10 pm is formed.

Then, a resist is patterned on this metal layer by photolithography technology, and the metal layer is etched using this resist as a mask to remove unnecessary portions of the metal layer. As a result, the selection electrode 11 and the common electrode 12 made of metal layers are formed in a staggered manner and spaced apart from each other. Thereafter, a polyimide adhesive 17 is applied in a band-like manner between the opposing ends 13, 14 of the selection electrode 11 and the common electrode 12 along the arrangement direction of each electrode 11, 12.

Next, as shown in FIG. 4, a fiber 16 having a thickness of approximately 50 μm is bonded to the film substrate 10 using an adhesive 17. Then, the fiber 16 has its upper part connected to each electrode 11.1.
It is provided so as to protrude above the upper surface of 2. At this time,
Since the fiber 16 has a circular cross section, the fiber 16
When the fiber 16 presses the adhesive 17, the excess adhesive 17 rises along the outer peripheral surface of the fiber 16. Thereby, the adhesive 17 is provided with a gentle slope between the outer periphery of the fiber 16 and the end 13.14 of each electrode 11.12.

Thereafter, after drying the adhesive 17, a thin film heating resistance layer 18 is formed on the fiber 16. In this case, there are two methods: one using a metal mask and the other using photolithography. The former method, as shown in FIG. 5, is a method in which a metal mask 22 is placed on a film substrate 10 and tantalum nitride is deposited on it. In this case, the metal mask 22 has a strip-shaped opening 23 formed at a location corresponding to the S* heating resistor JIJ18. Therefore, when the metal mask 22 is placed on the film substrate IO, only the region where the thin film heating resistor layer 18 is formed will be exposed. In this state, when tantalum nitride is deposited by sputtering and the metal mask 22 is removed, tantalum nitride is formed in a band shape only in the locations corresponding to the openings 23 of the metal mask 22 along the arrangement direction of the electrodes 11 and 12. be coated. As a result, a thin film heating resistor layer 18 is formed over the fiber 16, with both ends connected to the ends 13.14 of the electrodes 11.12.

Therefore, the heat generating portion of the thin film heat generating resistor MI18 in particular protrudes above other portions at a uniform height due to the fiber 16. Note that when the tantalum nitride is deposited, since the adhesive 17 is provided with a gentle slope between the fiber 16 and each electrode 11.12, the thin film heating resistance layer 18
Even if the wire is thin, it can be formed well without breaking.

In addition, in the latter method, tantalum nitride is deposited on the entire surface of the film substrate lO by sputtering, a resist is applied to the surface, a pattern is formed on this resist by photolithography technology, and the nitride layer is nitrided using this resist as a mask. This method involves etching the tantalum film and removing unnecessary parts. With this method as well, the WIM heating resistance layer can be formed in the same manner as described above.

In either method, when depositing tantalum nitride by sputtering, the film substrate 10 is cooled in a cooling device @24. A plurality of cooling pipes 26 are arranged under the metal plate 25, and a cooling liquid 27 is made to flow through the cooling pipes 26 to cool the pipe. In the experiment, when cooling is not performed, the film substrate 1051
Although it was heated to around 50 to 200°C, when it was cooled, the temperature was around 50 to 80°C, making it possible to form a uniform and flat tantalum nitride film without causing any thermal deformation on the film substrate. Ta.

Finally, as shown in FIG. 146, a protective layer 19 is provided on the entire surface to protect the thin film heating resistor layer 18 and the electrodes 11 and 12. This protective layer 19 has a two-layer structure. Therefore, first, Si02 was applied to the entire surface by thermal oxidation treatment or CVD (C
hei+1cal Vapor Deposition
) to form a moisture-resistant protective film 20, and then a wear-resistant protective film 21 is formed by growing Ta205 on its surface by CVD. In this case as well, since each of the protective films 20 and 21 is formed while being cooled by the cooling device 24, thermal stress is suppressed as described above.

Each protective film 20, 21 can be formed in a stable state. Further, the protection 1119 of the portion corresponding to the heat generating portion of the thin film heat generating resistor layer 18 is the protection M19 of the entire surrounding area.
Yosu is also formed with sufficient protrusion. Therefore, the heat generating portion of the thin film heat generating resistor 1j18 has good contact with the recording paper, etc., and it is possible to perform clear printing with good print quality.

Note that this invention is not limited to the embodiments described above.For example, the substrate need not be a film substrate, but may be a glass substrate, a quartz substrate, a ceramic substrate, etc. The resistance layer 18 is not necessarily made of tantalum nitride, but may be made of ruthenium oxide (Ru02) or polysilicon doped with ions.
Further, the protruding insulating layer that makes the thin film heat generating resistance layer 18 protrude is as follows:
It does not have to be the fiber 16, but may be one made of an insulating material such as 5i02 or 3iN grown in a convex shape.Furthermore,
The selection type all and common electrodes 12 do not necessarily have to be arranged in a staggered manner, and the ends 13. of each electrode 11.12.
14 may be arranged in a spaced-apart manner so as to face each other.

[Effects of the Invention] As described in detail above, according to the present invention, each electrode arranged on both sides of a protruding insulating layer on a substrate has a base portion on both sides of the protruding insulating layer. The thin film heat generating resistor layer connected with
Therefore, even if the interval between the heat generating parts becomes finer, there is no need to separate the heat generating parts of the thin film heat generating resistor layer.Therefore, the thin film heat generating resistor layer can be easily formed, and the thin film heat generating resistor layer can be easily formed. It is extremely easy to align the electrodes when superimposing them on each electrode, allowing for efficient production.

[Brief explanation of drawings]

FIGS. 1 to 6 show an embodiment of this invention. @Figure 1 is a sectional view taken along line A-A in Figure 2, Figure 2 is a plan view of the main part before the H-retaining layer is provided, and Figure 3 is a cross-section with electrodes and adhesive provided on the film substrate. Figure, Figure 4 j, fiber! 5 is a sectional view of the IC attached, FIG. 5 is a sectional view of the thin film heating resistor layer formed while cooling, FIG. 6 is a sectional view of the protective layer formed while cooling, and FIGS. 7 and 8.
The figures show a conventional example; FIG. 7 is a cross-sectional view of the main part thereof, and FIG. 8 is a plan view of the main part before the protective layer is provided. lO...Film substrate, 11...Selection electrode, 12...Common electrode, 16...Fiber (protruding insulating layer), 18... ...Thin film heating resistance layer. 16 fiber diagram diagram diagram diagram diagram diagram diagram diagram diagram diagram diagram diagram diagram diagram diagram diagram diagram

Claims (1)

[Claims] A protruding insulating layer is provided on the substrate, electrodes are arranged on both sides of the protruding insulating layer, and electrodes are connected to the electrodes at the bases on both sides of the protruding insulating layer by climbing over the protruding insulating layer. A thermal print head characterized in that a thin film heat generating resistor layer is formed in a strip shape along the direction in which the electrodes are arranged.