JPS608083A - Heat sensitive recording thermal head - Google Patents

Abstract

PURPOSE:To improve the workability such as the connecting characteristics of electrode and semiconductor element or the like and to raise its heat dissipating characteristics, by a method wherein the common electrode drawn extending it to the opposing end surface part is fixed to the side of projection part of base by pressure contact of common electrode out going lead via elastic materials. CONSTITUTION:The common electrode 81 is formed on the end surface forming a heating resistance film to the opposing end surface part and the heating element substrate 70 is constructed. The heating element substrate 70 is fixed by adhesives 11 and both ends fixing press plate 75 so that the common electrode going out lead 74 is pressure-contacted at the doubling part 74a of end surface part by elastic materials 76 such as rubber provided at the projection part of base 78 or the like. All surface of heating element substrate 70 sticks fast to the base 78 and if resin of good thermal conductivity is used for the substrate 70, its heat dissipating characteristics are further improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Use The thermosensitive recording method is easy to maintain, so it is used in many terminal printers including F2 page printers. Furthermore, in recent years, thermal transfer methods have been developed, making it possible to perform multi-color recording or full-color recording, and the development of new recording equipment has also been ruled out.

The present invention relates to a thermal head that is useful in a thermal transfer recording system that enables multi-color or full-color recording, and specifically relates to the structure of an edge-type thermal head in which a large number of heating elements are formed in a row on the end surface of a heating element substrate. .

Structure of a conventional example and its problems FIG. 1 shows the relationship between a thermal head and recording paper, which are often used in conventional monochromatic recording.

In FIG. 1, 11L is an image receiving paper, and 1b is a transfer paper. In this configuration, the image receiving paper 1a and the transfer paper 1b are integrated to form the recording paper 1. Reference numeral 2 denotes a paper feeding roller, and 3 a thermal head, each of which has a heating element row 3b formed on one of the two main planes of a heating element substrate 3a. This type of head is referred to as the flat type thermal head Toyofu.

3 In FIG. 1 on page 3, when the image receiver 1a and the transfer paper 1b are brought into pressure contact with the heating element row 3b of the thermal head 3 in the direction of the arrow by the paper feed roller 2, and the heating element row 3b is heated according to the image signal, Monochromatic recording can be performed on the image receiving paper 1a.

Although FIG. 1 shows transfer type recording, if direct coloring type thermal recording paper is used instead of image receiving paper 1a and transfer paper 1b, normal thermal recording type recording can be performed.

In contrast, in the present invention, a recording section as shown in FIG. 2 can be configured.

In FIG. 2, the thermal head 3' is a heating element substrate 3a.
The heating element row 3b is formed on one of the four surfaces (end surface) parallel to the thickness direction of the heating element.

Hereinafter, the head having the configuration shown in FIG. 2 will be referred to as an end-face type thermal head.

As can be seen from the comparison between Figures 1 and 2, even in the monochrome thermal transfer recording system, it is possible to see the recording state more quickly and to use an edge-type thermal head to configure the recording section. It has the advantage of being able to be used effectively. Furthermore, the recording paper 1 shown in FIGS. 1 and 2 is a case in which the image receiving paper 11L and the transfer paper 1b are integrated, but in general, the image receiving paper IL and the transfer paper 1b are fed by separate feeding mechanisms. It is configured so that it is sent and pressed into contact with the thermal head. In such a case, an end face type thermal head is very advantageous in terms of device design.

Furthermore, when color recording is performed using the thermal transfer recording method, the problem of color misregistration of multicolor dots can be solved with a simple configuration as shown in FIG. 3 using an edge-type thermal head.

In FIG. 3, the image-receiving paper 11L is wrapped around the paper feed roller 2 and fixed, and in this state, the image-receiving paper 1a is placed on the heating element array of the thermal head 3' (provided on the end surface that contacts the paper. The image receiving paper 1b is pressed against the image receiving paper 1b via the transfer paper 1b, and as the roller 2 rotates, the image receiving paper 1b is sent in the direction of the arrow. Cyan C, magenta M, yellow Y, and black B are sequentially coated on the transfer paper 1b to have the same width as the image receiving paper and a length that is approximately the same as the length of one revolution of the roller 2, as shown. The order of the five pages of the above-mentioned coating layers formed on the transfer paper varies depending on the conditions of the ink such as dye and pigment used.

Transfer each color of cyan, magenta, yellow, and black with each rotation of the paper feed roller (an operation that heats a heating element according to the image signal and prints only the heated portion of the dye or pigment on the transfer paper onto the receiving paper) If you do this, you can record in color.

The advantage of using image-receiving paper wrapped around a roller is that the device mechanism is simple, as shown in the figure, and the overlapping position of each color can be easily and reliably adjusted by adjusting the rotational position of the paper feed roller. .

Even if the planar head shown in FIG. 1 is used, it is possible to construct a recording section as shown in FIG. 3.

However, in this case, it is necessary that the surface of the thermal head shown in FIG. This limitation is a major problem with conventional planar heads.

That is, in the conventional planar thermal head, as shown in FIG. 1, covers 30 and 3d are provided on the surface of the heating element substrate 31L on which the heating element row 3b is formed. It is provided for the purpose of mechanically protecting the semiconductor elements connected to each heating element of the tank or the lead wires connected to the electrodes of the heating elements.

On the other hand, in order to perform color recording using the method shown in FIG. 3, the length of the outer periphery of the roller around which the image receiving paper 1a is wound must be at least longer than the short side of the recording screen. In the case of monochromatic recording as shown in Fig. 1, the roller diameter is usually about 20cm in diameter, whereas in order to record 86 plates using the method shown in Fig. 3, the roller diameter is about 5QM. It is necessary to do so. The diameter of this roller increases as the size of the recording paper increases.

As a result, in order to configure the recording section as shown in FIG. 3 with a flat head, the heating element substrate 3& must be made larger than that in the case of a monochromatic recording device.

Increasing the size of the heat generating substrate greatly increases the price of the head, and also increases the size and cost of the color recording device itself.

In addition, there is another problem as follows.

7 In page color recording, the heating element row of the head is required to contact the transfer paper and the image receiving paper with very uniform pressure contact, but the flatness that satisfies this is required for the flat head. It is difficult to obtain this with a heating element substrate.

On the other hand, as shown in FIG. 3, with an end-face type head, the head shape is not affected even if the roller diameter changes, and the head can be made smaller. Moreover, since the heating element array is formed on the end face, it is possible to ensure flatness.

As described above, edge-type thermal heads are particularly useful when used in thermal transfer recording systems, but they are more difficult to manufacture than conventional planar-type thermal heads. The main reasons are as follows. The first is the technology for forming a continuous pattern on the end face of a flat plate, or the bidirectional plane, the second is the heat dissipation of the heating element substrate, and the third is the method for taking out the common electrode lead and the method for connecting the individual electrodes and semiconductor elements. .

Figure 4 shows the implementation of a conventional planar thermal head.

An example of assembly is shown. l', -1 FIG. 4 shows an IC (3) having a drive circuit having a shift register and a latch function as a semiconductor element, and this IC is connected to the individual electrodes of a heating element by a film carrier. In Figure 4, 431L is an alumina substrate with glass glazed;
43b is a heating element, 430 is a common electrode, 43f is an individual electrode, 44 is a common electrode lead, 46 is a semiconductor element, 4
6 is a film carrier, 47 is a printed circuit board, 48 is a base, 49 is a common electrode 43e and a common electrode drawer 44.
An example of soldering with is part. Note that a wear-resistant protective film is provided on the heating element, but it is not shown.

Integrated drive circuit including shift register and latch
By using C, the number of heat generating elements driven simultaneously can be arbitrarily changed, and therefore the printing speed can be dramatically increased compared to the diode matrix method. Furthermore, in the head of this system, the common electrode 4313 is commonly connected to all the heating elements, and basically only one connection to an external circuit is required, and the number of lead wires can be reduced. From these points, it is thought that many future thermal heads will use ICs.

From page 9, when increasing the number of waste heat bodies to be driven simultaneously, it is very important to make the resistance value (referred to as Rc) of the common electrode portion sufficiently small.

The table shows the variation (Pn/P1) in the power applied to the heating elements due to Rc when the number of heating elements driven simultaneously is changed. Note that n in the table is the number of heating elements driven simultaneously, and Ri is the resistance value of the heating elements.

As can be seen from the table, if the number of heating elements driven simultaneously is 256 dots, Rc is 0.1% of the heating element resistance value (R, R).
However, when 256 dots are simultaneously heated, the power is reduced by 10 pages, or 63 times, compared to when only one dot is heated, and the print density changes greatly.

Such fluctuations in the power applied to the heating element have a very large adverse effect on the image quality of color recording.

In color recording, it is necessary to control the size and density of each colored dot, and it appears that Rc is required to be approximately 0.01% of the resistance value (RH) of the heating element.

In order to meet such requirements, in the conventional planar thermal head shown in FIG.
Soldering 49 is applied to f3 to reduce RC and prevent changes in print density.

By the way, the head in which a heating element is formed on the end face, for example,
There are heads in which a heating element and electrodes are formed on the circumferential surface of a round glass rod, and heads in which a resistor is formed by diffusion on the end face of a semiconductor silicon single crystal substrate.

However, these heads have poor heat dissipation and thermal efficiency.

In addition to problems in terms of high density, etc. (C) the above-mentioned inability to reduce the resistance value of the common electrode portion, it is not suitable as a recording head.

11. As an end face type head for page color and color recording, there is a head shown in FIG. 6 which was devised by the present inventors. The bed shown in Figure 6 uses a substrate with a glass glaze on the end surface and the top surface of an alumina substrate, which is inexpensive and has good thermal conductivity, and uses a heating element substrate on which a heating element and electrodes are formed using a thin film forming process. It was there. This method solves the above-mentioned problems in pattern formation of the edge type head.

In this heating element substrate, the end face of the heating element is sandwiched between two
Electrodes are formed on the two main planes, and therefore assembly and mounting are performed as shown in FIG.

In FIG. 6, 1o is a heating element substrate with a heating element on its end face and a common electrode on the base 8 side, 45 is a semiconductor element, and 46
is a film carrier, 47 is a printed circuit board, 8 is a base,
6o is a common electrode lead.

FIG. 6 shows a cross section taken along the line A' in FIG. The same numbers as in Figure ε indicate the same names. In FIG. 6, 11 is an adhesive layer for insulating and bonding the heating element board and the base, 12 is a soldering part for soldering the common electrode of the heating element board and the common electrode lead at regular intervals, and 13 is a soldering layer for bonding the heating element board and the base. is an insulating layer, 636
is a common electrode, 63f is an individual electrode, 14 is a heating resistor film,
18 is a wear-resistant protective film, including these, the heating element substrate 1'O
Configure.

The common electrode lead 5o is connected to the common electrode of the heating element substrate at regular intervals by soldering through grooves provided in a part of the base. Such an end face type head has problems such as firstly poor workability and secondly poor heat dissipation due to the small area of the heating element substrate in contact with the base.

OBJECTS OF THE INVENTION It is an object of the present invention to improve the workability of connecting electrodes and semiconductor elements, and to achieve good heat dissipation.

Constituent structure of the invention In the end face type head, it is essential to form the electrode film on the end face where the heating element is formed and the two main planes, but in this case, the electrode film is formed on the end face where the heating element is formed and the end face opposite to the end face where the heating element is formed. is also formed. There is no problem in extending the common electrode to this opposing end surface. Furthermore, when a semiconductor element is mounted using a film carrier, it is necessary to provide a protrusion on the base in order to improve heat dissipation from the semiconductor element itself.

In the present invention, the common electrode extended to the opposing end surface is fixed to the side surface of the protrusion of the base by pressing a common electrode lead made of a film lead or a lead wire through an elastic material such as rubber. It consists of:

DESCRIPTION OF EMBODIMENTS FIG. 7 shows an embodiment of the present invention. In Figure 7, 7
0 is a heating element substrate, 46 is a semiconductor element, 46 is a film carrier, 47 is a printed circuit board, 48 is a base 974, which is partially bent by a common electrode lead, and has a bent portion 7.
4! It is pressed into contact with the common electrode on the opposite end surface by L. Ryo6
is a holding plate that presses and fixes the heating element board against the protrusion of the base 78, and is fixed to the base with screws 77.

14 Page 76 is rubber for elastically pressing the common electrode lead.

FIG. 8 shows a cross section taken along line BB' in FIG. 7. In FIG. 8, 14 is a resistor film formed on the end face, and 18 is a wear-resistant film 6jf, which is also formed on the end face and protects the resistor film and the electrode.
A solid electrode 8' and a common electrode 8' are formed up to the end surface opposite to the end surface on which the heating element is formed, and these constitute a heating element substrate 70. The heating element substrate To is connected to the common electrode lead 7 by a rubber 76 provided on the protrusion of the base.
4 is fixed with the adhesive 11 and the fixing leg plates at both ends so as to be pressed together at the bent portion 742L of the end face.

In the structures shown in FIGS. 7 and 8, the common electrode lead for connecting the common electrode of the heating element substrate and the external circuit can be connected by simply press-contacting the common electrode, so that work efficiency is greatly improved. Further, since the entire surface of the heating element substrate To is brought into close contact with the base 78, heat dissipation is improved.

Furthermore, since the heating element board To is fixed with the holding plate 76, conventional adhesive is not required, and therefore it is possible to use a resin with better thermal conductivity, which also improves heat dissipation. be able to.

The common electrode drawer 74 can be freely pressed into contact with the common electrode on the opposite end surface of the heating element substrate at a plurality of arbitrary positions. Therefore, the resistance value (Re) of the common electrode portion can be made sufficiently small, and no problems arise as a color recording head.

Another great advantage is that after the heating element substrate 70 is pressed and fixed, it can be mounted on a film carrier in exactly the same way as a conventional head.

As shown in FIG. 9, a groove is provided in a part of the base 78, and a part 74b of the common electrode lead T4 is inserted into this groove.
By bending and recessing the common electrode resistance, it is possible to more reliably reduce the common electrode resistance. Since the groove provided in the base 78 is wide enough to accommodate the bent common electrode lead, the contact area of the heating element board with the base is almost the same as that of the entire surface, and therefore heat dissipation is improved. As it decreases.

Effects of the Invention The common electrode can be connected to an external circuit by pressure contact at a plurality of locations using a common electrode lead with sufficiently low resistance, and workability in assembling the thermal head is greatly improved. Further, since the resistance value of the common electrode portion can be made sufficiently small, no problems arise as a color recording head. It is a great advantage that the problem of contact resistance of the pressure contact part does not occur at all because the pressure contact part is pressed more during use.

Furthermore, the heating element substrate can be in close contact with the base over almost the entire surface, improving heat dissipation. In fact, the heating element substrate does not need to be glued like in conventional heads, improving workability, and it is also possible to use resin with good thermal conductivity, further improving heat dissipation. In addition, since the film carrier method used in conventional heads can be used to connect the individual electrodes of the heating element and the semiconductor elements, the cost of the head is low in that new equipment investment is not required and reliable mounting is possible. It has a great effect on increasing reliability and reliability.

[Brief explanation of drawings]

Figure 1 shows color-forming thermal sensitivity using a conventional flat head.
17-page schematic diagram for performing 0 recording or monochrome thermal transfer recording, FIG. 2 is a schematic diagram for performing monochrome thermal transfer recording or recording on color-forming thermal paper using an edge type head, and FIG. FIG. 4 is a schematic diagram of color thermal transfer recording performed using an edge-type head; FIG.
Figure 6 shows a conventional umbrella mounted using the film carrier method in which a heating element is mounted on the end face of a flat plate. Figure shown, 7th
9 and 9 are views showing a thermal head according to an embodiment of the present invention, and FIG. 8 is a view showing a cross-sectional shape taken along line 73-'B' in FIG. 7. 46... Semiconductor element, 46... Film carrier, 47... Printed circuit board, 70...
...Heating element board, 74...Common electrode extraction lead, 741L...Bending portion, 76...
...Press plate, 76...Rubber, 78...
・Base. Name of agent: Patent attorney Toshio Nakao and 1 other person @
1 Figure @2 Figure 3 Figure 5 Figure 6 Figure 8 Figure 5

Claims (1)

[Claims] Heating elements formed in a row on the end face of an electrically insulating flat plate, individual electrodes formed on one of the two main planes extending from the end face on one of the two main planes sandwiching the end face, and one main plane other than the end face. A heating element substrate comprising a common electrode extending through a plane to an end surface opposite to the end surface, and a protrusion, and a film lead or lead wire is connected to the above through an elastic member at one side surface of the protrusion. A film carrier having a base that is press-fitted to a common electrode on the opposite end surface and integrally connected with a semiconductor element for driving each of the heat generating elements is used to insulate the individual electrodes of the heat generating elements and the base. A thermal head for heat-sensitive recording that connects multiple conductors provided through a base material.