JPS608084A - Thermal head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Use The thermosensitive recording method is easy to maintain and is therefore used as printers for many terminals including facsimile machines.

Furthermore, in recent years, thermal transfer methods have been developed, making it possible to perform multicolor recording or full color recording, and are being developed as new recording equipment. The present invention relates to a thermal head used in this heat-sensitive recording method.

2.B.2 Structure of the conventional example and its problems FIG. 1 shows the relationship between the thermal head and recording paper used in conventional thermal transfer recording.

In FIG. 1, 1a is an image receiving paper, 1b is a transfer paper, 2 is a paper feed roller, 3 is a thermal head, and the thermal head 3 has heating elements 3b formed in a row on a heating element substrate 3a. Although not particularly shown, on both sides of the heating element 3b,
A common electrode and an image signal electrode are formed, and the common electrode is connected to the lead wire 3.
In c, the image signal electrodes are respectively connected to the heating element driving semiconductor elements 3g on the heating element substrate 3a. Covers 3h and 3j are respectively provided for the purpose of mechanically protecting the common electrode connecting portion or the connecting portion with the heating element driving semiconductor element portion and the heating element driving semiconductor.

In FIG. 1, the paper feed roller 2 transfers the transfer paper 1b and the receiver paper 1a.
is brought into pressure contact with the heating element 3b of the thermal head 3 and sent in the direction of the arrow while heating the heating element 3b according to the image signal.
Recording can be performed on the receiver paper 1a. In FIG. 1, if a direct coloring type thermal recording paper is used instead of IJlb, a recording section of a normal 3-beta-ζ゛ thermal recording system is constructed. Further, in Fig. 1, for example, yellow, magenta, and cyan transfer layers (not shown in the figure) are provided on the transfer paper 1b, and each time one transfer layer is formed, the image receiving paper 1a is turned in the opposite direction to the arrow. Color recording can be performed by repeating this process three times, in which the recording medium is moved, stopped at the recording start position, and the next transfer layer (not shown) is transferred to the image receiving paper 1a.

In the thermal head configured as described above, the cover provided on the heating element substrate 3aJ- for mechanical protection has a shape that improves the formation of the heating element 3b on the heating element substrate 3a. The paper feed roller 2 needs to be configured so that it comes into pressure contact with the heating element 3b and does not come into contact with the mechanical protective covers 3h and 3j, which imposes restrictions on the paper feed roller. On the other hand, the paper feed roller increases the length of 11 and 12, which causes an increase in the cost of the thermal head.

FIG. 2 shows a thermal head used for conventional color transfer recording, in which image-receiving paper 1a is wound around a drum 2I, transfer layers of cyan, yellow, magenta, etc. are provided on the image-receiving paper 1b; It is constructed so that color recording is performed by transferring one transfer layer m each time ' is rotated once. In this case, the overlapping position of each transfer layer is determined and adjusted by the rotational position of the rotary drum 2. In this method, the length of the short side of the image receiving paper 1a is at least the length of the drum 2.
Since the diameter of the drum 2' increases, the lengths of the drums 11 and 12 explained in FIG. 1 are limited by the drum 2'. A2 becomes longer, and the heating element substrate 3a becomes larger. Therefore, the cost of thermal head 3) U
This will be a significant increase.

Fig. 3 shows a conventional thermal head used in the direct recording method, which is similar to the thermal head shown in Fig. 1, but as shown in Fig. 1, when 41 becomes longer, the recording state changes. It is slow to view, and it is necessary to cut the recording paper 1 if it is in a roll.
At this time, the distance between the position of the heating element 3b and the cutting position (not shown) becomes longer. Therefore, after cutting, the recording paper 1 is fed in the opposite direction to the feeding during recording, so as to reduce the irregular portion of the recording paper 1. In such a case, when feeding the recording paper, the protective cover 3h protrudes from the surface on which the heating element 3b is formed, so the leading edge of the recording paper 1 is exposed to the protective cover 3h.
This caused repeated jamming. Therefore, the cost of the thermal head 3 has been increased by making the protective cover 3h part a resin molded structure.

FIG. 4 is a diagram showing a schematic configuration of a thermal head and a device used in conventional thermal recording, but the difference from FIGS. 1 to 3 is that As shown in FIGS. 5 and 6, the common electrode 3k is configured to extend toward the individual electrode 3m side through both sides on which the heating elements 3a are arranged, and is connected to the lead 130. be. In this type of heating, the problem explained using FIG. A wide electrode width p5 is required in order to reduce wiring resistance in the direction of arrangement of electrodes 3a. This is
If the wiring resistance is thick, the resistance value will change near both ends and the center in the arrangement direction of the heating element, and when the same voltage is applied between the lead wire 30 and the image signal electrode, the resistance value will change in the center. The wiring resistance causes a voltage drop and the heating elements do not generate heat in the same way, resulting in uneven printing density in the main scanning direction (the direction in which the heating elements are arranged). In order to reduce the resistance, the diameter of the electrode can be made wider or thicker, but increasing the thickness is difficult in the manufacturing process and involves cost-cutting, so generally speaking, the diameter of the electrode can be made wider or thicker. It is made wider. Furthermore, according to this method, the wider the recording area (the longer the length in the arrangement direction of the heating elements), the wider the electrode needs to be, and the substrate becomes larger in both length and width, which increases the cost of the thermal head. This increases the distance 11'u from the heating element 3a to the end, which poses problems such as restricting device design.

7/C-'' As described above, when using a conventional thermal head, the size of the heating element substrate increases, which increases the cost and increases the constraints on the device design.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a thermal head that can reduce costs and reduce constraints on the design of the device.

Structure of the Invention The present invention aims to reduce the cost of the thermal head and reduce constraints on device design by integrally forming a common electrode on the back surface passing through the end surface and connecting lead wires on the back surface of the heating element. It is something that can be done.

DESCRIPTION OF EMBODIMENTS FIG. 7 is a diagram showing a recording apparatus using a thermal head according to an embodiment of the present invention. In FIG. 7, 4 is a recording paper, 5 is a paper feed roller, and e (4 is a thermal head.The paper feed roller 6 presses the recording paper 4 against the heating element 6 && of the thermal head 6, and moves the recording paper 4 in the direction of the arrow. By heating the heating element 6a in accordance with both signals while feeding the recording paper 4, recording can be performed on the recording paper 4.

The thermal head 6 will be explained in detail below using the drawings.

In FIG. 8, 7 is a heating element substrate, 8 is a base, 9 is a semiconductor element for driving the heating element, 10 is a semiconductor element protection cover, 1
1 is a lead wire.

A plurality of heating elements 61L are formed in a row on the heating element substrate 7, and a common electrode element a and a picture signal electrode 7b are formed on both sides of the heating elements. Further, as shown in FIG. 9, the common electrode 71 is integrally formed on the back surface passing through the end surface. Further, a drive electrode 7C for driving the heating element driving semiconductor element 9 is formed at the end on the image signal electrode 7b side. The drive electrode 7C is constituted by a connection pattern 701 which is tangential to the heating element driving semiconductor element 7C by wire bonding, and a connection terminal part C2 to the outside. Image signal electrode 7
One end of b is connected to the heating element 6a, and the other end 9A°-2' is connected to the heating element driving semiconductor element 9 by wire bonding. The heating element substrate is adhesively fixed to the base 8 through an insulating material of polyimide. A part of the base 8 is provided with a relief part 8a for the lead wire 11. The lead wire 11 is connected to the common electrode 7 extending on the back surface of the heating element substrate 7 at the position of the relief part Sa of the base 8 as shown in FIG.
A... is added.゛The semiconductor protective cover 16 is fixed to the heating element substrate 7 with double-sided tape on both sides of the heating element driving element 9 with a space between the heating element driving element 9 and the heating element driving element 9 to mechanically protect the heating element driving element 9 from the outside. I am installing it.

In addition, in order to prevent the temperature of the heating element driving element 9 from rising, a thermally conductive compound is provided between the heating element driving element 9 and the semiconductor protective cover 1o, so that the semiconductor cord protective cover 10 can be used as a heat sink. are doing. The common electrode 7a is configured to have a sufficient width using the end surface and the back surface so that wiring resistance does not become a problem. Therefore, the heating element 6a
The heating element 2L is provided at the very end of the heating element board 7 from the regeneration ρ4 on the (support) surface of the heating element board 7.

As described above, according to this embodiment, the common electrode is provided using the end and back surfaces of the heating element substrate, and by providing the heating element at the very edge of the heating element substrate, the heating element substrate can be made smaller and cost-effective. This allows the thermal head to be made smaller. In addition, it eliminates the need for a protective cover for the common electrode, shortens the distance from the heating element to the end of the heating element substrate (the end of the thermal head), and reduces constraints on the device configuration. .

Further, in this embodiment, the common electrode of the lead wire 11 is soldered, but it goes without saying that a film lead or the like may be used for pressure contact connection.

Effects of the Invention In the thermal head of the present invention, the common electrode is provided on the end surface and the back surface, and the length between the heating element and the end surface of the thermal head is shortened, thereby reducing the cost and size of the thermal head and improving the installation. The constraints on the -4 configuration can be reduced, and its practical effects are great.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a thermal transfer recording device using a conventional thermal head, Fig. 2 is a diagram showing a rotating drum type thermal transfer color recording device using a conventional thermal head, and Fig. 3 is a diagram showing a thermal transfer color recording device using a conventional thermal head.
The figure shows a direct thermal recording device using a conventional thermal head, FIG. 4 shows a direct thermal recording device using a conventional thermal head, and FIG. 5 is a partially enlarged perspective view of the thermal head in FIG. 4. 6 is a perspective view of the thermal head in FIG. 4, FIG. 7 is a diagram showing a direct thermal recording device using the thermal head of the present invention, and FIG. 8 is a partially enlarged perspective view of the thermal head of the present invention. FIG. 9 is a partial perspective view showing the back surface of the heating element substrate in the present invention. 6...Thermal head, 6! L...Heating element, 7...Heating element substrate, 7T...Common electrode, 7b...Picture signal electrode, 8...Group Stand, 11...Lead wire. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 424 Figure 6 Figure 9

Claims (1)

[Claims] A heating element substrate comprising a plurality of heating elements formed in a row, a picture signal electrode on one side of the heating element, and a common electrode extending through an end surface to the back surface on the other side of the heating element, and a back surface of the heating element substrate. A thermal head comprising: a base mounted so as to be in contact with each other through an insulating member; and a lead wire connected to a common electrode on the back surface of the substrate.