JPH0627418Y2 - Thermal head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a thermal head used in a thermal printer.

[Conventional technology]

It is sectional drawing which shows the general structure of the conventional thermal head of this kind of FIG. A glaze layer 2 made of glass having a substantially arcuate cross section is formed on an insulating substrate 1, and a heating resistor layer 3 made of tantalum nitride (Ta ₂ N) or the like is formed on the glaze layer 2. ing.

Further, a power feeding layer 4 made of aluminum (Al) or the like for feeding power to the heating resistor layer 3 is formed on the heating resistor layer 3, and the glaze layer of the power feeding layer 4 is formed. The top surface of 2 is divided by means such as etching, and one is connected to the common electrode line 5 and the other is connected to the individual electrode line 6. Furthermore, a protective layer 7 is formed on the heating resistor layer 3, the power feeding layer 4, the common electrode line 5 and the individual electrode line 6. The protective layer 7 is an oxidation resistant layer 8 made of silicon dioxide (SiO ₂ ) or the like for protecting the heating resistor layer 3 from deterioration due to oxidation.
And a wear resistant layer 9 made of tantalum pentoxide (Ta ₂ O ₅ ) or the like for protecting the heat generating resistor layer 3 and the power feeding layer 4 from abrasion due to contact with a thermal recording medium (not shown) or the like. There is.

Then, the heating elements having the above-described structure are linearly arranged on the same substrate, and the voltage is selectively applied to the individual electrode lines 6 according to the information so that the heating resistor layer 3 located on the top surface of the glaze layer 2 is located. Is generated, and this heat is transmitted through the oxidation resistant layer 8 and the abrasion resistant layer 9 to generate heat in the heat generating portion 7a on the surface of the protective layer 7 to give coloring energy to the thermal recording paper, the ink ribbon and the like.

[Problems to be solved by the invention]

However, in the above-described conventional thermal head, when printing is performed while moving in the direction of arrow A, the cross-sectional shape of the heat generating element is substantially arcuate, so the contact area with the ink ribbon (not shown) is large and the ink melted by the heat generating portion 7a. Since the distance t from the transfer of the ink onto the paper surface to the peeling of the ink ribbon is long, the ink cools during this time and the bonding force between the transferred ink and the ink ribbon is greater than the bonding force between the paper surface and the transferred ink. However, the ink peeling phenomenon occurs, the printed characters are incomplete, and the printing quality is degraded.

Further, since the peeling angle θ ₁ is small, there is a problem in that the transferred ink is poor in ink and the printed characters are blurred and the printing quality is deteriorated.

Further, since the bottom area S ₁ of the glaze layer 2 is large and a large amount of heat generated in the heating resistor layer 3 escapes to the insulating substrate 1, there is a problem that the thermal efficiency is poor.

An object of the present invention is to solve the above problems and to provide a thermal head having high printing quality and good thermal efficiency.

[Means for solving problems]

According to the present invention, in a thermal head, a glaze layer is formed at one end on the upstream side of the insulating substrate with respect to the moving direction of the thermal head during printing.
It is characterized in that a projecting portion on which the heat generating portion is formed is provided, and the upstream side of the projecting portion is formed as a steeply sloping portion near the top surface portion of the projecting portion.

[Action]

Since the protrusion that forms the heat generating portion is provided on the glaze layer,
Improves the pressure contact with the ink ribbon during printing. Further, since the upstream side in the moving direction of the protruding portion during printing is a steeply inclined portion that is close to the top surface of the protruding portion, the peeling distance t of the ink ribbon after transfer from the recording medium is shortened, and the peeling angle θ. _{As 1} increases, the bottom area S ₁ of the glaze layer decreases.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of the thermal head of the present invention.

A glaze layer 12 made of glass is formed on the insulating substrate 11. The glaze layer 12 is steeply inclined by first forming a protruding portion 12b on the arc-shaped portion by a first etching process as shown by a dashed line and then removing one end by a second etching process. The part 12a is formed. On the glaze layer 12, tantalum nitride (Ta
₂ N) or the like is formed on the heating resistor layer 13, and a power feeding layer 14 made of aluminum (Al) or the like for feeding power to the heating resistor layer 13 is formed. The top surface portion of the glaze layer 12 of the body layer 14 is divided by means such as etching. And one is the common electrode line
15 and the other is connected to the individual electrode line 16. Furthermore, a protective layer 17 is formed on the heating resistor layer 13, the power feeding layer 14, the common electrode line 15, and the individual electrode line 16. This protective layer 17 protects the heating resistor layer 13 from deterioration due to oxidation.
O ₂ ), etc., and the tantalum pentoxide (Ta ₂ O ₅ ), which protects the heating resistor layer 13 and the power feeding layer 14 from abrasion due to contact with the thermal recording medium (not shown), etc. The wear-resistant layer 19 is made of. As shown in FIG. 1, the heating resistor layer 13 is formed on the steep slope 12a of the glaze layer 12,
Since the feeder layer 14 and the protective layer 17 are formed, the protective layer 17
Also has a steep slope 17a. And the heating elements having the above-mentioned structure are linearly arranged on the same substrate,
The thermal head is completed by cutting at the braking line 20 adjacent to each steep slope 17a.

When printing is performed while moving the above-mentioned thermal head in the direction of arrow B in FIG. 1, since the steeply inclined portion 17a exists in the position close to the heat generating portion 17b, the ink of the ink ribbon (not shown) is melted. Since the distance t from the transfer of the ink ribbon to the paper surface to the peeling of the ink ribbon becomes short and the angle θ _{2 of} peeling the ink ribbon from the paper surface becomes large, the ink solidifies after the ink of the ink ribbon is transferred. Since the ink ribbon can be rapidly peeled off from the surface of the paper in advance, there is no ink peeling phenomenon and high-quality printing with good ink cut-off becomes possible. Also, the heating unit 17
Since b is projected more than other portions, the pressure contact with the ink ribbon is improved and the thermal conductivity is improved. Further, since the bottom area S ₂ of the glaze layer 12 is small, the heat generated in the heating resistor layer 13 that escapes to the insulating substrate 11 is small, so that the thermal efficiency is improved.

[Effect of device]

As described above, in the present invention, the glaze layer is formed at one end portion on the upstream side of the insulating substrate with respect to the moving direction of the thermal head during printing, and the protrusion is formed on the glaze layer by etching. Since the heat generating portion is formed on the protruding portion, and the steep slope portion is provided on the upstream side of the protruding portion in the vicinity of the top surface portion of the protruding portion, the press contact property with the ink ribbon is improved, and The distance from the time when the ink of the ink ribbon is melted and transferred to the paper surface to the time when the ink ribbon is peeled off becomes short, and the angle at which the ink ribbon is peeled off from the paper surface becomes large, so there is no ink peeling phenomenon, Moreover, high-quality printing with good ink cut-out is possible, and the bottom area of the glaze layer is small, and the heat escaping to the insulating substrate is small, resulting in improved thermal efficiency. An effect.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional example. 11 …… Insulating substrate 12 …… Glaze layer 12a …… Steep slope 12b …… Projection 13 …… Heating resistor layer 14 …… Feeder layer 17 …… Protective layer

Claims (1)

[Scope of utility model registration request] 1. A glaze layer is formed on one end of an insulating substrate, a plurality of heat generating portions are formed on the glaze layer, and an ink ribbon is interposed between the heat generating portion and a recording medium. In a thermal head in which ink is melted by heat and transferred to the recording medium, the glaze layer is formed at one end on the upstream side of the insulating substrate with respect to the moving direction of the thermal head during printing. A thermal head characterized in that a projecting portion on which the heat generating portion is formed is provided on the glaze layer, and the upstream side of the projecting portion is a steeply sloped portion that is close to the top surface portion of the projecting portion.