JPS6285959A - Thermal head - Google Patents

Abstract

PURPOSE:To minimize the effect of heat accumulation in the first heating element array, eliminate the one-side contact of the heating elements due to their run and maintain printing quality by forming the varying heights of a plurality of protrusion arrays or the different height of only some array on an insulative substrate and arranging heating elements on each protrusion array. CONSTITUTION:In a thermal head provided with two arrays of heating elements, for instance, a heating element array 2A preheats the protrusion 3B beneath a heating element array 2B when heating element arrays 2A, 2B are used to print alternately at high speed. To prevent this, the preheating effect of the protrusion 3B has only to be minimized. Accordingly, this minimization can be achieved by reducing the height of the protrusion array 3B and minimizing the thermal capacity. In addition, the protrusion array at the head or rear of a thermal head moving direction is more raised or lowered, and the thermal head is mounted and moved. Thus the one-side contact of the heating elements by their run can be eliminated to assure satisfactory high-quality printing. The height of the protrusion is easily formed by the number of times of glass paste printing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to, for example, a thermal head for high-speed recording that includes two rows of heating elements.

[Conventional technology]

FIG. 2 shows, for example, a conventional thermal recording device disclosed in Japanese Patent Publication No. 51-36074 (FIG. 2 (5) is a plan view, and FIG. 2 CB) is a cross-sectional view). Figure 5 is the second
Conventional THERMA is an improved version of the thermal recording device shown in the figure! The head (Figure 5) is shown in a perspective view, and Figure 5(B) is a sectional view. ).

In Figures 2 and 5, +1) is an insulating substrate, (2) is a heating element ((2A) and (2B) are heating element rows).
, (loj is the 4th resistance film, (12) is the earth'i square pole,
(13) is the drive electrode, +1411'i insulating thin film, U
51, (16) is a lead wire, and the snout is a pulse! ! ■It is the source of motion, and in Figure 5, (3) is the protrusion ((3A) (3
B) shows a row of protrusions. )(4) is the recording paper, and (5) is the platen.

Next, the operation will be explained. A pulse voltage is applied to the dots formed by arranging several heating elements (2) on the insulating plate (fl), and the heat generated by the dots produces characters on the recording paper (4).
The method for printing symbols, etc. is thermal recording, thermal transfer recording14
The print head is a thermal head. Here, an insulating thin film (6) of Si02, Ta205, etc. is provided on the heating element (2) for the purpose of preventing oxidation and preventing wear.

Now, for the purpose of high-speed printing using a low-cost thermal head, the system shown in FIG. 2 was devised and implemented. This is equipped with two rows of a plurality of heating elements (2) on an insulating substrate (1), and a pulse drive source αη through which a lead wire +51. A pulse voltage is applied from the heating element rows (2A) and (2B).
By alternately driving υ, it is possible to print at twice the speed compared to a case where the heating element row is a single row, while ensuring the necessary cooling time. This situation is shown in the printing results in FIG. 3 and the printing timing chart in FIG. 4.

In the figure, C11, C12, . . . indicate a print string, D indicates a reference clock pulse train, three ties in the movement of the recording paper (4), E indicate three drive ties in the heating element row (two people), F shows the drive tie three of the heating element row (2B).

Now, in the thermal recording device shown in FIG. 2, like the device shown in FIG. 1 to 1, running in the direction of the arrow H in the figure, the dots of the heating elements (2) arranged by applying a pulse voltage,
Characters, symbols, etc. are printed. After this printing, the recording paper (4) is conveyed by the rotation of the platen rubber (6) in the direction of the arrow J by a distance equal to the number of dots of the arranged heating elements (2). Continuous printing is done. Therefore, the stopping of the heating element (2) in the direction of the arrow in the H direction and the alternate application of pulses to all the element columns (2A) and (2B) are responsible for printing one line.

By the way, there is a certain relationship between the contact pressure between the source element (2) and the recording paper (4) and the printed dots printed on the recording paper (4). ), the coloring density is high and the print quality is good, so in order to improve the seal between the heating element (2) and the recording paper (4) and increase the contact pressure, the heating element (2) is Protrusions on trench substrates were devised and implemented. As shown in Fig. 5, this protrusion (3) is made by using, for example, a ceramic substrate as the insulating substrate +11, printing a glass paste on it with a width of about 1 mm and a thickness of several μm, and baking it at several hundred degrees Celsius. In particular, it is easily formed into a semi-cylindrical shape. This protrusion row (
3A) and (3B) are formed with almost the same thickness by screen printing, so the heat storage due to the heat generated by the heating element (2) should be the same for each heating element row (2A) and (2B). When pulses are applied alternately at high speed, due to the running direction and the heat accumulation of the heating element row (2 people) to which the pulses were applied, the same pulse as the heating element row (2 people) is applied to the heating element row (2B). When the voltage is applied, the printed dots on the heating element row (2B) are larger than the printed dots on the heating element row (2 people).
As a result, printing quality becomes unsatisfactory.

Also, due to the shadow 4 of the pressing force G and the running direction H, the thermal head will not be able to apply force to the platen rubber (5) in an inclined direction, and will not be able to apply force to the platen rubber (5). However, the thermal head hits the recording paper (4) unevenly while running, resulting in unsatisfactory print quality.

[Problem that the invention seeks to solve]

Conventional thermal beds are configured as described above, so in order to print at a higher height, it is necessary to control the heating element array and the rapid pulse application. There were problems such as the need to attach a thermal head to prevent one side of the row from hitting one side.

This invention was made to solve the above-mentioned problems.
It is an object of the present invention to provide a thermal bed which can eliminate the -f-] control and which does not hit unevenly on only one side of the 41-child row.

[Problems (Means for Immediate Decision on i7i)] The thermal head according to the present invention has a plurality of protrusion rows on an insulating substrate whose heights are different for each row or for only one row. Heat generating elements are arranged on a row of protrusions.

[For production]

For the thermal head in all of these questions, the height of the protrusion row on the leading side in the direction of movement of the thermal head is +1+1, and the protrusion row on the rear side is b, gl.
There is a characteristic of l< or lower.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figures, (A) is a perspective view, and (B) is a sectional view. f
il is an insulating substrate, (2) is a heating element ((2A), (2B)
) indicates a row of heating elements. ), f+01 is a thin film resistive film, (1 is the ground side La is a drive electrode, (14) is an insulation 4 pattern, (3) is a protrusion ((3A) and (3B) are a row of protrusions.) , fil is recording paper, (51Vi platen).

Next, the operation will be explained. The function of the thermal head is the same as the conventional one, so it will be omitted.

Now, it is clear that the heat storage effect of element (2) is due to the protrusion (3), which has poor thermal conductivity, and the heating element rows (2A) and (2B) are printed alternately at high speed. In such a case, the heat from the heating element row (two people) preheats the protrusion (3B) at the bottom of the heating element row (2B),
2A) and (2B) complex markings on flannel insteps - must be controlled. To prevent this, as shown in FIG. 1, the preheating effect of the protrusion row (3B) can be reduced, and therefore the height of the protrusion row (3B) can be reduced.
What you need to do is to make the dry bunker smaller.

In addition, the protrusion row on the front side in the direction of movement of the thermal head or on the rear 1d side may be made higher or narrower.
By mounting and moving the thermal head, uneven contact of the emitting element array due to running can be avoided, and satisfactory printing quality can be obtained.

Through actual practice and moxibustion, the authors found that the thermal head was installed at an angle of 1 to 2 with respect to the platen (5), and the brightness of the protrusion row (3A) was set to 60 μm, as shown in Figure 1. By setting the total height of the protrusion row (3B) to 40 μm, an effect was obtained in which the printing quality could be improved by an additional a. The height of this protrusion can be easily formed with four strokes of color paste.

In the above embodiment, the case of two rows of heating elements (2A) and (2B) facing each other is shown, but as shown in FIG. Alternatively, it may be a case of two or more rows of heating elements, and the same effects as in the above embodiment can be achieved. Note that Fig. 6 (A) is a perspective view and Fig. 6 (B)
is a sectional view, and the symbols are the same as in FIG.

Furthermore, in the above embodiment, the case of recording paper (4) was explained, but when an ink ribbon is used, such as in thermal transfer recording, the peeling angle between the ink ribbon and the heating element array affects the print quality. This is related to the height of the protrusions in the front row and the rear row, and making the heights of the protrusions in either row different is effective in improving printing quality.

〔Effect of the invention〕

As described above, according to the present invention, the heights of the plurality of protrusion rows on the insulating substrate are made different for each row or only one row, and the heating elements are arranged on the protrusion rows. By arranging them, the influence of heat accumulation in the heat generating element rows of the light array can be reduced, and uneven contact of the heat generating element rows due to running can be eliminated, resulting in satisfactory printing quality.

[Brief explanation of drawings]

FIG. 1 is a perspective view and a KL sectional view showing a thermal head according to an embodiment of the present invention, FIG. 2 is a plan view and a KL sectional view showing a conventional thermal recording device, and FIG. 3 is shown in FIG. The printing results of the thermal recording device are shown in FIG. 4, the printing result of the printing tie, and FIGS. 5 and 6 are perspective views showing a conventional thermal head, and a KLfr diagram. (1) is an insulating substrate, (2
) is a heating element, (2A) and (2B) are heating element rows, (
3) is a protrusion, and (3A) and (3B) are protrusion rows. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (4)

[Claims] (1) In a thermal head that has multiple rows of protrusions on an insulating substrate and heating elements are arranged on the protrusions, it is important to note that the heights of the protrusion rows differ from row to row or only for one row. Features a thermal head. (2) The thermal head according to claim 1, characterized in that heating elements are arranged on two rows of projections. (3) The thermal head according to claim 1 or 2, wherein the protrusion is made of glass and has a nearly semicircular shape. (4) The thermal head according to claim 1, 2, or 3, wherein the height of the protrusion row on the thermal head movement direction side is higher than the other rows.