JPH01141064A - Electrode construction in thermal head - Google Patents

Abstract

PURPOSE:To dispose adjacent heating resistors close to each other to enable a sharp image to be expressed, by a method wherein two electrodes opposed to each other are made different in width. CONSTITUTION:Where a first electrode 4a has a width G1, a second electrode 4b has a width G2, and a width between adjacent heating resistors 1 is G3, the width G1 of the first electrode 4a and the width G2 of the second electrode 4b are respectively set to be the same as the widths of the end parts of heating resistors 1 to be connected thereto. The width G3 between the adjacent heating resistors 1 is set smaller than that of the prior art. The smaller the width is the larger the current density and heating value are. In this way, if the conduction time or wave height value of an electric current to pass through the heating resistor 1 is small, only the small-width part of the heating resistor 1 heats to a value sufficient to melt an ink. Thus, only the ink of an ink surface facing this part is melted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrode structure of a thermal head used in a thermal printer.

[Prior art] Figures 2 and 3 are a plan view and a cross-sectional view, respectively, showing the configuration of a conventional thermal head. In these figures, 1 is a heat-generating low antibody with different widths at both ends, and is made of aluminum oxide. They are arranged in a plurality of rows on a substrate 2 with a thermal insulating layer 3 interposed therebetween, and electrodes 4a and 4b, which will be described later, are formed on the upper surface at a predetermined distance apart.

Here, the surface of the heat generating hypoantibody 1 exposed between the electrodes 4a and 4b becomes the heat generating portion 1a. In addition, adjacent fever-low antibody 1
The directions are alternate. Here, reference numeral 4a denotes a first electrode, which intersects with one end of the heat-generating low antibody 1 and is integrated with a common electrode 4c arranged on the same substrate. A second electrode 4b overlaps the other end of the low heat generating antibody 1 and is connected to a power supply control section (not shown). A protective film 5 is formed to cover the low heat generating antibody 1, the first electrode 4a+the second electrode 4b, and the common electrode 4C. In addition, G
1 is the width of the first electrode, G2 is the width of the second electrode, G3
indicates the width between the adjacent fever-reducing antibodies 1, and G1 and 62
have the same length.

In the above configuration, the second
? When a current flows through the low fever antibody 1 through the Ti electrode 4b,
Due to a known action, this thermogenic hypoantibody 1 generates heat, melts ink (not shown), and prints.

By the way, the reason why the widths of both ends of the hypothermic antibody 1 are made different is as follows. Generally, in a hypothermic antibody, the narrower the width, the higher the current density and the greater the amount of heat generated. Therefore, if the current flow time or the peak value of the current flowing through the heat-generating low antibody 1 is small, only the narrow part of the heat-generating low antibody 1 generates enough heat to melt the ink, so this part Only the ink on the facing ink surface is melted, and if the current flow time or the peak value of the current applied to the heat-generating low antibody 1 is increased, the heat-generating low antibody 1 will be melted accordingly.
The ink on the ink side facing the wide part of the ink is also melted. Therefore, by making the widths of both ends of the hypothermic antibody 1 different, and controlling the duration or peak value of the current flowing through the hypothermic antibody 1, the size of the printed dots can be controlled. Can be done. Further, the direction of the adjacent antipyretic antibodies 1 is alternately changed in order to uniformly transfer the dots and throats without being biased to either the top or bottom, and to prevent the characters from being distorted.

[Problems to be Solved by the Invention] By the way, if the width G3 between adjacent thermogenic hypoantibodies 1 is made as narrow as possible, the area where the ink is not transferred will be reduced and the printed image will be clearer, so this width G3 is It needs to be as narrow as possible. However, since the width G1 of the first electrode 4a and the width G2 of the second electrode 4b are the same, there is a limit to how narrow the width G3 can be, and it is impossible to make the width G3 closer than the limit interval determined by the shape. However, there was a problem in that the required image clarity could not be expressed.

[Means for Solving the Problem] This invention narrows the width between adjacent hypothermic antibodies by making the widths of the two electrodes connected to both ends of the hypothermic antibodies different, and It solves problems.

[Embodiment] FIG. 1 is a plan view showing an embodiment of the present invention, in which the same reference numerals as in FIG. 2 indicate the same configuration as in FIG. 2. What is different in FIG. 1 from FIG. 2 is that the first electrode 4
The width G1 of the first electrode 4a and the width G2 of the second electrode 4b are the width G1 of the first electrode 4a, the width G2 of the second electrode 4b, the width G3 between adjacent heat generating low antibodies 1, and the width G2 of the second electrode 4b, respectively. The width should be the same as the width of the end. In addition, adjacent fever-low antibody 1
The width G3 between them is narrower than that shown in FIG.

In the above configuration, this thermal head performs the same function as the conventional one, but produces the following effects compared to the conventional one.

[Effects of the invention] In this invention, since the widths of the two opposing electrodes are made different, that is, the widths of these electrodes are not fixed and the same width, heat generation can be performed freely adjacent to each other without considering shape problems. This method has the advantage of being able to bring low-intensity antibodies closer together, and providing a thermal head that can express much clearer images than before.

Note that the widths of the first electrode 4a and the second electrode 4b do not necessarily have to be the same as the width of the ends of the heat generating hypoantibodies 1 that are in contact with them (but may vary depending on the width between adjacent heat generating hypoantibodies 1). Just make it the appropriate length.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a single side view of a thermal head having a conventional electrode structure, and FIG. 3 is a sectional view taken along line Δ-A in FIG. 1... Low fever antibody 2... Substrate 3... Thermal insulating layer 4a... First electrode 4b... Second electrode 5... Protective layer

Claims (1)

[Claims] A trapezoidal heat-generating low antibody installed on the top surface of the substrate with a heat insulating layer interposed therebetween, and a heat-generating low antibody having one side overlapping a narrow part of the heat generating low antibody and the other side overlapping a wide part of the heat generating low antibody. In a thermal head in which a first electrode, a second electrode that supplies current to the antibody, and a protective layer that protects the surface are sequentially laminated; the width of the first electrode and the width of the second electrode are different. The electrode structure of the thermal head is characterized by: