JPS59178267A - Thermal head - Google Patents

Abstract

PURPOSE:To improve resolution and obtain smooth pictures by a thermal head wherein a heating resistor and a plurality of electrodes driving the heating resistor are formed on a substrate, and the part of the heating resistor corresponding to between the adjacent electrodes is notched. CONSTITUTION:When recording a picture on a heat sensitive recording medium with the color density being graded, voltage or pulse width of a driving current supplied to individual separate/electrodes 13 must be controlled by a driving control circuit. At this time, a part of the difference in voltages or pulse widths of the driving current supplied to the separate electrodes 13, 13 adjacent to each other is caused to pass through a common part 12a. The common part is heated up to an intermediate temperature between those of heating resistor 1 on both sides thereof, so that the heat sensitive recording medium is colored at the intermediate density dependingly on the corresponding common parts of the heating resistor 12. Thus, it becomes possible to make recording with density having continuous gradation without causing any blank part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal recording device (a thermal head used therein), and particularly to a printing device ζ used for recording an image on a thermal recording medium such as thermal recording paper. Regarding useful thermal heads.

[Background technology and problems]

2. Description of the Related Art Conventionally, a thermal spatula 1', as shown in FIG. 1, is known, which is used to heat-sensitively record desired patterns such as characters or symbols on heat-sensitive recording paper.

This thermal head shown in FIG. An individual electrode 3 is connected to one end of each, and a common electrode 4 which is common to each heating resistor 2 is connected to the other end. The thermal head configured in this way is
A drive current is selectively supplied from the drive circuit section to the heat generating resistor 2 via the individual electrode 3, and the heat generating resistor 2 to which this drive current is supplied is selectively made to generate heat, which mainly causes the thermal recording paper to be heated as described above. By moving the heat-generating resistors 2 in a direction perpendicular to the arrangement direction, they sequentially record ζ pixel points on the thermal recording paper, thereby recording a desired pattern such as characters or symbols on the thermal recording paper. do.

By the way, in the conventional thermal head as described above, since a plurality of heating resistors 2 are provided independently, the heating resistors 2 adjacent to each other generate heat to record a pixel on the thermal recording paper. Even in this case, blank areas where coloring is not performed occur between adjacent pixel points, and differences in color density occur between the pixel points. Therefore, the above-mentioned normal head is not suitable for use in a printing device that records something that requires continuous color development, such as an image. In other words, with conventional thermal heads, recording on thermal recording paper is performed as dots,
To create a difference in color density between consecutive pixels,
This is because when recorded as an image, the difference in color density is visually observed, resulting in a so-called coarse-grained image.

Therefore, in order to solve the above-mentioned problem of the conventional thermal head, in which the heating resistors are provided independently and can only record images as pixels on the thermal recording medium, we have developed A thermal head has been proposed which is capable of recording an image by developing color and making the color density uniform in gradation. As shown in FIG. 2, this →normal head has one heating resistor 2 arranged in a band shape on an insulating substrate 1, and a plurality of individual electrodes 3 connected to one side of this heating resistor 2. , a plurality of lead electrodes 4a of a common electrode 4 having a common base end on the other side are connected to the individual electrodes 3 facing each other. In the thermal head configured in this way, if the heating resistor 2 is made to generate heat by selectively supplying a drive current with a different voltage or drive pulse width from the drive circuit to the plurality of individual electrodes 3, At the same time, the portion of the heating resistor 2 corresponding to each individual electrode 3 generates heat according to the voltage difference or driving pulse width of the current supplied to the individual electrode 3, and at the same time, the heating resistor 2 is formed in a strip shape with the same width. Since they are formed in a row, the driving current is also shunted to the part corresponding between each individual electrode 3 and generates heat.Then, the part where the pixel is old corresponding to each individual electrode 3 is supplied with the driving current. Heat is generated according to the current voltage or drive pulse width, and pixels with density differences are recorded on the heat-sensitive recording medium, and the areas between the pixels are also colored, unlike the thermal head 1- described above. It is possible to record images, etc., by having color densities with gradations without creating blank spaces. However, in a thermal head in which such heating resistors 2 are successively provided with the same width, The color density between the pixel points becomes more than a predetermined density, and when visually observed, the resolution between each pixel deteriorates and the recorded image becomes blurry, making it impossible to obtain a high-resolution image. Can not.

There are no blank areas formed between the pixels and differences in density, and each pixel is arranged to have a gradation so that each pixel is connected with a continuous density and a clear, high-quality image with high resolution is obtained. This was proposed for the purpose of providing a thermal head.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides a thermal head in which a heating resistor and a plurality of electrodes for driving the heating resistor are formed on a substrate. A notch is formed in the heating resistor portion.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

In the device shown in FIG. 3, a continuous heating resistor 12 is provided on an insulating substrate 11, a plurality of individual electrodes 13 are connected to one side of the heating resistor 12, and a proximal end is connected to the other side. A plurality of lead electrodes 14a of the common electrode 14 having a common electrode 14 are connected so as to be located opposite to each other between the individual electrodes 13, and further, a common lead electrode 14a is connected to a portion of the heating resistor 12 corresponding to between the individual electrodes 13 and 13 adjacent to each other. A V-shaped notch 15 that tapers toward the electrode 14 side is provided, and a V-shaped notch 15 is also provided in a portion of the heating resistor 12 corresponding to between the mutually adjacent lead electrodes 14a, 14a of the common electrode 14 toward the individual electrode 13 side. A V-shaped cutout portion 16 is provided which tapers off.
The structure is such that 16 heating resistors 12 are removed.

When notches 15 and 16 are provided in the heat generating resistor 12 as shown in FIG.
13 and the lead electrode 14a of the common electrode 14 corresponding between these individual electrodes 13.13.
A shared portion 12a of the heating resistors 12 shared by the heating resistors 13 is formed.

In this thermal head, when recording an image on a heat-sensitive recording medium so that the color density has gradation,
The voltage of the drive current supplied to each individual electrode 13 or 1
This is done by controlling the pulse width of the rolling current with a drive control circuit, and at this time the individual electrodes 1 adjacent to each other
A part of the voltage difference or the pulse width difference between the drive currents supplied to 3.13 flows into the shared portion 12a, and the heat generated in the shared portion 12a is generated between the heating resistors 12 on both sides. It generates heat, and the color is developed on the heat-sensitive recording medium at an intermediate density between the areas corresponding to the heat-generating resistors 12 on both sides, and a continuous gradation is produced without creating a blank area as shown in FIG. 1 mentioned above. Furthermore, as shown in FIG. 2, there is no difference in color density and there is no continuity, and the recorded image can be smooth and homogeneous.

Further, in the case shown in FIG. 4, each lead electrode 1'4a of each individual electrode 13 and common electrode 14 is provided so as to face each other, and there is a correspondence between each individual electrode 13 and between each lead electrode m14a of the common electrode 14. U-shaped cut portions 25 and 26 are provided so as to face the heat generating resistor 12 portion, and each IJ of each individual electrode 13 and common electrode 14 corresponds to each other.
(A narrow continuous portion 22a is provided to connect the heating resistor 12 between the electrode 14a and the electrode 14a.

In addition, the one shown in FIG. 5 is provided with diamond-shaped cut portions 35 in opposing portions of each individual electrode 13 and each common electrode 14 in the heating resistor 12, and between each individual electrode 13, 13 and each common electrode 14i4. A V-shaped notch 36 between each
The continuous portion 22a of the heating resistor 12 is formed in the central portion.

Furthermore, in the case shown in FIG. 6, a cutout portion 45 is provided so that the heating resistor 12 is formed between the individual electrodes 13 and the common electrode 14 facing each other,
The notch portion 46 is provided so as to cross so as to connect the adjacent individual electrodes 13 and the common electrode 14 to form a shared portion 12a of the heating resistor 12.

As shown in FIG. 4, FIG. 5, and FIG. 6 described above, cutout portions 25, 26, 35°, 36.45° are formed in the heating resistor 12.
46, and the continuous portion 22a or shared portion 12a of the heat generating resistor 12 is provided in a portion corresponding to between the adjacent individual electrodes 13 and 13, as shown in FIG. Continuous part 2 as above
2a or the individual electrodes 1 adjacent to each other in the common part 12a
3. Part of the voltage difference or pulse width difference between the drive currents supplied to the drive currents 13 flows into the continuous portion 22a or the shared portion 12a, and the heat generated in the continuous portion 22a or the shared portion 12a is generated on both sides. heating resistor 1
2, and a color develops on the heat-sensitive recording medium at a density that is between the areas corresponding to the heating resistors 12 on both sides, without producing blank areas as shown in FIG. This eliminates the problem, and the recorded image can be made clear and homogeneous.

That is, in the present invention, if the common part 12a or the continuous part 22a of the heating resistor 12 is formed in the part corresponding to the adjacent individual electrodes 13 and 13, the cut part The shape may be (, zz 1"L).

In the embodiment described above, the individual electrodes 13 and the common electrode 14 that drive the heating resistor 12 are concentrated on one side, respectively.
The same can be applied to a structure in which 4 are provided alternately.

〔Effect of the invention〕

According to the present invention as described above, when recording with gradation in color density (zero resolution), it is possible to record with clear and homogeneous image quality, and it is possible to record with a clear and homogeneous image quality. This makes it possible to provide an optimal thermal head.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the structure of a conventional thermal head, and FIG. 2 is a plan view showing the structure of a conventional thermal head. FIG. 3 is a partial plan view showing one embodiment of the present invention, FIG. 4 is a partial plan view showing another embodiment of the invention, and FIG. 5 is a partial plan view showing still another embodiment of the invention. FIG. 6 is a partial plan view showing still another embodiment of the present invention. 11...Insulating substrate 12...Heating resistor 13...Individual electrode 14...Common electrode 15 .16, 25, 26, 35, 36, 45.46...
...Notch portion patent applicant Sony Corporation representative Patent attorney Kodo Koike 1) Sakae Mura - Figure 1 Figure 2 B. Figure 3 Figure 4

Claims (1)

[Claims] In a thermal head formed of a heating resistor and a plurality of electrodes for driving the heating resistor formed on a substrate, a cutout portion is formed in the heating resistor portion corresponding to the space between the adjacent electrodes. A thermal head.