JPS62216762A - Thermal head - Google Patents

Abstract

PURPOSE:To obtain excellent printing quality even on a paper having a low smoothness, by a construction wherein only the vicinity of an opening part of heat generating elements of a thermal head is brought into contact with a transfer recording paper so that a contact surface pressure sufficient for flattening the surface of the paper can be secured even when a pressing force is small. CONSTITUTION:Peak parts of projected parts 103a, 103b of a partial glaze 103 on a thermal head 101 press flat the projected parts of the surface of a transfer recording paper 106, and make close contact with the recessed parts of the surface. With the single partial glaze 103 thus provided with a plurality of the projected parts 103a, 103b, the total width of the thermal head 101 can be reduced, and when the head 101 is pressed against the paper 106, a pressing angle is stably fixed, In addition, since the heat generating elements 104a, 104b are proximate to each other, printed density is uniform in a printing direction. With the heat generating elements 104a, 104b disposed on both sides of the partial glaze 103, a surface pressure at this part can be set to a minimum required value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head for a thermal printer suitable for use with transfer paper having low smoothness.

[Conventional technology]

Conventional thermal heads have a structure in which a heating resistor is placed on top of an arcuate glass glaze, as described in JP-A-59-76272, in order to obtain high printing quality. An example is known in which the efficiency of transmitting thermal energy to the transfer paper is improved by providing the i-.

The heat transfer printer has the advantage of being able to print on perspiration paper, in line with the demand for free selection of transfer paper.

It was necessary to be able to print clearly even on N1, which has poor smoothness. For this purpose, it is important to print by bringing the heating element of the thermal head into close contact with the transfer paper via the ink ribbon.

The inventors' experiments have confirmed that it is difficult to print high-quality characters on low-life I current paper by simply improving the thermal energy transfer efficiency as described in AU.

FIG. 8 shows an external perspective view of a general thermal head used in a thermal transfer printer. In the figure, a thermal head 1 is constructed by providing a partial glaze 3 on a head substrate 2 made of an insulator such as ceramics, and disposing a heating element 4 on the upper layer.

FIG. 9 shows a sectional view taken along the line AA in FIG. As shown in Figure P, 1, the heating element 4 is provided with an opening 50 that covers the upper layer of the arc-shaped partial glaze 3 and is sandwiched between the electrode 7 and the common pole S at the top of the partial glaze 3. There is. Furthermore, partial glaze 3 has 1 on its top surface! Extreme 7. A protective layer 9 is provided to protect the common electrode 8 and the opening 50 of the heating element 4. This protection M9 is provided by the opening 8 (IS) of the heating element 4.
This prevents the electrodes 7 and common electrodes 8 from being oxidized by direct contact with the outside air, and also prevents the heating element 4 and the electrodes 7 from being oxidized by the thermal head running over the paper surface and the ink ribbon (or transfer film). This is to prevent the common electrode 8 from being worn out. By heating the opening 50 of the heating element 4 through the pole 7 and the common electrode 8, thermal transfer is performed on the paper. Furthermore, the shape of the partial glaze 3 of the conventional thermal head 1 has a glaze width w=80.
0 to 1000 μm glaze height h = 30 to 50 μm, one dimension W is much larger than dimension hK, and the radius of curvature r of the glaze is approximately 2000 μm, which is also larger than W, so the top of partial glaze 3 The area is approximately flat. Note that the above dimensions w, h, and r are general values determined by the glass material of the glaze.

The opening 50 of the heating element 4 at the top of the above-mentioned portion glaze 3 is also configured in a substantially planar shape, and the height dimension H1 of the top of the heating element 4 is equal to that of the electrode 7. The height H2 of the top of the common electrode 8 is also reduced by approximately the thickness ζl~2 μm of the t-pole layer. Similarly, the protective layer 9 is a Vt electrode, and the common electrode 8
Since it is deposited to a uniform thickness on the opening 50 of the heating element 4, the protective layer 9a is the upper layer of the opening 50 of the heating element 4.
The height ζ dimension 113 of is 1! 7, the height H4 of the uppermost protective layer 9b of the common electrode 8 is smaller by approximately the thickness of the electrode layer. Therefore, the opening 50 of the heating element 4 is lower than its surroundings and has a concave shape, resulting in very poor adhesion between the thermal head and the transfer paper. This significantly reduces print quality when paper with low smoothness is used.

The reason for this will be explained using FIGS. 10 and 11.

FIG. 10 shows a thermal head 1, an ink ribbon 5. FIG. 6 is an enlarged cross-sectional view showing the contact state of the transfer paper 6;
FIG. 11 is a diagram showing the pressure distribution on the contact surface between the transfer paper 6 and the thermal head 1 in the state shown in FIG. 10. 1st
As shown in Figure 0, the dimensional difference between the convex portions 6a and the concave portions 6b on the surface of the low smoothness paper is 10 to 28 μm%.The pitch between the concave portions 6b and the concave portions 6b is approximately 80 to 300 μm. On the other hand, the width d of the opening 500 of the heating element 4 is determined by the size of the printed dot, and is generally 120 to 180 mm.
It is μm. In this way, since the recesses on the surface of the low smoothness paper are deep and large 1 and the openings 50 of the heating elements 4 are recessed, the openings 50 through the ink ribbon 15 and the four parts of the transfer paper 6 do not come into contact with each other. . Therefore, even if the opening 50 generates heat and melts the ink on the ink ribbon 5, the ink cannot adhere to the surface of the transfer paper 6, resulting in missing prints.

In order to solve this problem, the contact surface pressure near the opening 50 of the heating element 4 must be increased. By making it bigger.

It is necessary to deform the surface of the transfer paper 6 and temporarily make it flat.

However, in the past, even if the contact pressure between the thermal head l and the transfer paper 6 and ink ribbon 5 was increased.

Since the opening 50 is concave, Vc9b comes into contact with it before the protective layer 9a comes into contact with it, and the surface pressure of the opening 50 does not increase. 1. As described above, the effective contact width t between the thermal head 1 and the transfer paper 6 via the nearly flat squid-line crib 5 on the surface of the heating element 4 also becomes thick.

Therefore, the contact area increases unnecessarily, and in order to increase the contact surface pressure of the opening 50, the thermal head 1 requires a huge pressure of up to 2 kg.

FIG. 11 is a diagram showing the contact surface pressure distribution between the transfer paper 6 and the thermal head 1 in the state shown in FIG. 10. As shown in the figure, only the contact surface pressure of the convex portion of the paper increases, and the surface pressure of the opening 50 necessary for transfer does not increase.

[Problem that the invention seeks to solve]

With the spread of thermal transfer printers, increasing the pressing force on the thermal head 1 increases the running resistance of the thermal head 1 in order to provide printing quality that is almost f'L on plain paper 1c whose surface smoothness is not very good. However, there is a problem in that f'L cannot be achieved without increasing the driving force of the carriage on which the thermal head 1 is mounted and increasing the size of the printer as a whole.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal transfer printer capable of solving the above-mentioned problems and providing excellent print quality even on paper with low smoothness.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention makes use of the inherent elasticity of the transfer paper and temporarily presses the irregularities of the paper during transfer to flatten the surface and transfer it to low-smoothness paper. This enables printing by ensuring that only the area near the opening of the heating element of the thermal head comes into contact with the transfer paper, making it possible to keep the paper surface flat even if the pressing force of the thermal head is small, without making the contact area too large. Ensure that there is sufficient contact surface pressure to In order to reduce the contact area between the thermal head and the transfer paper, the width of the thermal head is made small and the number of chevrons is made plural, thereby determining the optimum size of the partial glaze.

Further, the opening of the heating element is configured to be located at the top of the chevron-shaped portion, so that this portion first comes into contact with the heating element and the surface.

[Effect]

The contact surface pressure per unit area near the partial gun of the thermal head becomes large, and the paper surface is temporarily elastically deformed, the convex portion becomes flat, and the convex portion enters the concave portion, causing the V-maru head and the ink ribbon to press against the transfer paper. This makes it possible to achieve the objective of t)@ layer.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 7 is an external view of a thermal transfer printer to which the present invention is applicable, in which the VCC thin shaft 8 and the stem 34 are fixed between the side plate 24 and the Ill plate 4 (). Also, it is possible to slide on the shaft 38 and the stay 34 VC=? A spear 32 is arranged, on which a ribbon cassette 30 and a thermal head 1 are placed.
The ink ribbon 5 is stored in the ribbon cassette 30. Carriage 32 is driven by motor 2
6, it is configured to be movable in the direction of the arrow and the direction of the arrow via the timing belt 44. Gear 18 fastened to the shaft of line feed motor 20 and paper feed motor 63
The transfer paper 6 is sent by transmitting the driving force to the transfer paper 6. The transfer paper 6 is configured to run between a paper feed roller 63 and a presser roller 64, and enter the flat platen 62 and the ink ribbon 5 via the platen support plate 61. Reference numeral 22 denotes a roller knob exclusively for paper feeding, which allows the paper to be fed by hand. 42 is a paper guide. Also release lever 1
By operating 6, the paper presser 14, which is slidably disposed on the shaft 15, can be attached to or detached from the paper surface. 36 is a home return detector, and 28 is a belt-like cable for supplying electricity to the thermal head 1.

This printer uses a unidirectional printing method that prints only when the carriage 32 moves in the direction of the arrow R, and when the carriage 32 moves in the direction of the arrow, the ink ribbon 5 is not wound up. Also, a carriage motor 26, a life feed motor 20. Thermal head 11 origin return detector 36, etc. are powered by an 80V Al regulator.
C distortion is resistant.

Next, the vertical structure of the partial glaze of the thermal head of the present invention will be explained using the first layer.

Generally, when the upper surface of a trapezoid is pressed against a piece of paper or cloth under tension in the longitudinal direction, a large amount of pressure is applied to both sides.

Using this, as shown in Figure 41, both 11
There are chevron-shaped parts 103a, 103b of the number of phases near the part. establish.

At the tops vc of the chevron-shaped portions 103a, 103b, heating elements]04a, 104b are formed by vapor deposition. Further, t-poles 107a and 107b are provided on both sides of the partial glaze 103, respectively, and are disposed in the valley portion 103C of the common electrode 108.

Heating elements 104a, 104b, electric power 107a.

107b, a protective layer 109 is provided on the common electrode 108. Height Hl to the top of heating elements 104a, 104b
is the height H+ of the top of the electrodes 107a, 107b and the common electrode 108.
The shapes and dimensions of the chevron portions 103a and 103b are set. Since the thickness of the protective layer 109 formed by normal vapor deposition is uniform, the opening fW150 of the heating elements 104a and 104b
The height H4 to the protective layer 109a of the electrodes 107a,
107b.

This is higher than the height H3 of the common electrode 108 to the protective layer 109b. However, even if Hz<H+, the protective layer 109
By applying VC etching, the heating element 104a,
The thickness of the a-retaining layer 10.9 of the opening 150 of 104b is the same as that of the a-retaining layer 10 of the electrodes 107a, 107b and the common electrode 108.
By making the thickness thicker than 9b, it is also possible to set H4>Hs.

If the related dimensions are set as described above, the two heating elements 104a
, 1o4b, the upper protective layer 109a of the opening 150 comes into contact with the transfer paper through the ink ribbon 105 first. According to experiments conducted by the inventors, a preferable contact state with the transfer paper 106 is obtained when H1 is set to be larger than Hl, and H4 and H3 are set to be larger by about 5 μm or more.

ζ et al. the chevron portion 103a of the partial glaze 103;

In order for the top part of the glaze 103b to come into close contact with the recessed part of the transfer paper 106, a preferable dimension is 10 μm vertically downward from the top part of the chevron parts 103a and 103b of the one-part glaze 103.
The width of the chevron portion 1038°103b is approximately 200μ at the time of
m, and the difference h1 between the peaks a 103a, 103b of the partial glaze 103 and the valleys 103C is about 15 μm.

Also, Yamagata EfI1103 a and 1 of partial glaze 103
(Since the pitch p of 13b is set to an even multiple of the pitch of the printed dots, that is, the length of the heating elements 104a, 104b in the printing direction, the heating elements 104a, 104t) vc
This prevents double printing due to

In FIG. 7, the thermal head 101 is connected to the flat platen 62.
When the upper transfer paper 106 is pressed FE.

It is preferable to set the width d to 3 to 6 times the width d of the partial glaze 103 so that only the openings of the heating elements 104a and 104b come into contact with each other and do not contact other parts.

With the above configuration, high quality printing can be obtained even with a relatively small pressing force against the thermal head 101. In other words, as shown in Figure @2, the thermal head 101
The tops of the chevron portions 103a and 1oab of the partial glaze 103 press against the convex portions of the transfer paper 106 to flatten them. Also, it adheres closely to the four parts. FIG. 3 shows the contact surface pressure distribution between the transfer paper 106 and the thermal head 101 in FIG. 2? Since the contact width t is small, the thermal head 101vC4 can obtain the surface pressure necessary for transfer even if the pressing force is small.
Good printing can be obtained even on low smoothness paper.

As described above, one partial glaze 103 has a plurality of chevrons t.
By providing 103a and 103b, the overall width of the thermal head 101 can be reduced to ζ〈〈, and the thermal head 10
1 pressed onto the transfer paper 106, the thermal head 1
The suppression angle of 01 is stable and does not tilt. Furthermore, a heating element 104a.

104b are close to each other, there is no unevenness in print density in the printing direction. Heating elements 1 on both sides of the partial glaze 103
By distributing 04a and 104b, the surface pressure in this portion can be reduced to the minimum necessary size.

84Fyi shows another example of the thermal head of the present invention, in which the heating elements 104a and 104b on the partial glaze 103 of the thermal head 101 are divided and arranged in a staggered manner, and the printing dot pitch p1 is also the same as the heating element 104 pitch p2. It is designed to increase the size of . As a result, the heating element 104a is better than the one in which the heating elements 104a and 104b are arranged in a fir row.

1114b vertical row length 8dl? x - Can be made larger.

Therefore, when printing vertical lines, the printed dots become clearer. 5 shows a cross section taken along line AA in FIG. 4, and FIG. 6 shows a cross section taken along line BB in FIG. 4. As shown in these figures, the chevron portion 1oaa of the partial glaze 103.

The shape of the heating element 103b is obtained by leaving one of the two chevron-shaped peaks of the embodiment in FIG. 1 and etching the other to remove its top.

The height of the glaze removed by the height gh of 104b is set to be greater than h'. With the above configuration, one heating element 104a+104b comes into contact with the transfer paper 106 in an infantile manner, and the minimum contact surface pressure necessary for printing can be obtained. Further, in this embodiment, two or more rows of partial glazes 103 may be provided for high-speed printing.

〔Effect of the invention〕

According to the VC of the present invention, the mountain-shaped portions of the partial glaze of the thermal head are temporarily flattened as are the convex portions of the transfer paper.

In addition, the contact area between the transfer paper and the partial glaze of the thermal head can be made small, and the contact surface pressure necessary for printing can be ensured even with the pressing force against the active thermal head. The ability to print on low-grade paper using conventional printer loading has the same excellent print quality as on straw-quality paper. Tru.

[Brief explanation of drawings]

Figure 1 is an enlarged cross-sectional view of a partial glaze of the thermal head according to this duplex, Figure 2 (2) is an explanatory diagram of the contact state of the thermal head, ink ribbon, and transfer paper in Figure 1, and Figure 3 is an explanatory diagram of the state of contact between the thermal head in Figure 1, the ink ribbon, and the transfer paper. The contact surface pressure distribution diagram in the figure, Figures 4 to 6 are enlarged views of the partial grooves V-7 of other embodiments of the present invention, and Figure wJ7 is an external perspective view of a thermal transfer printer to which the present invention is applicable. ,8g
Fig. 8 is a perspective view of a conventional thermal head, Fig. 9 is an enlarged sectional view of a conventional partial glaze, and Fig. 10 shows a partial glaze of the thermal head shown in Fig. 9 and an ink ribbon applied to the paper σ] contact bar. FIG. 1 is a contact surface pressure distribution diagram of FIG. 10. 101...Thermal head, 102...M&, 10
3... Partial group V-z, 103a, b... Yamagata part, 1
o3C...Taniform part, 104...Heating element, ios river ribbon 06...Transfer paper, 107a, b.
...pole, 108...common electrode, 109...protective layer, 150...opening 3rd eye grass 41 Figure 2

Claims (1)

[Claims] 1. A thermal head having a partial glaze on a substrate, and having electrodes on the partial glaze for energizing a plurality of heating elements and a protective layer for protecting them, wherein the partial glaze has a plurality of electrodes on the partial glaze. What is claimed is: 1. A thermal head characterized in that a row of chevrons is provided, and a heating element is disposed at the top of the row of chevrons. 2. The thermal head according to claim 1, wherein a row of chevron portions is provided at each end of the partial glaze. 3. The thermal head according to claim 1, characterized in that a common electrode is provided in the valley-shaped portion between the rows of photothermal elements. 4. The thermal head according to claim 1, wherein the spacing between the heating element rows is set to an even multiple of the printing dot pitch. 5. The thermal head according to claim 1, wherein the width of the partial gray is set to 3 to 6 times the width of the heating element. 6. The vertical dimension difference between the valley part and the peak part is 15 μm.
A thermal head according to claim 1, characterized in that the thermal head has the above. 7. The thermal head according to claim 1, wherein the heating elements are arranged in a staggered manner, and the pitch of the heating elements is larger than the pitch of printed dots. 8. The thermal head according to claim 7, wherein the chevron-shaped portions of the partial glaze are arranged in a staggered manner, and a heating element is provided at the top of the chevron-shaped portions. 9. The shape of the chevron-shaped portion of the partial glaze is configured such that the width dimension at a position 10 μm vertically downward from the top portion is 200 μm or less.
Thermal head described in section. 10. Claim 1, characterized in that a plurality of partial glazes having a plurality of chevron rows are provided on the substrate.
The thermal head according to any one of items 9 to 9.