JPH04251759A - Serial type thermal head - Google Patents

Abstract

PURPOSE:To manufacture a small-sized head having high density by forming heat generating sections onto a heat-resistant substrate and glazed glass formed near both left and right ends of the substrate and forming a connecting terminal section at the central section of a substrate section. CONSTITUTION:Glazed glass 2 is shaped bisymmetrically near the end faces of a heat-resistant insulating substrate 1, and heat generating sections 3 are formed onto the glazed glass 2. The heat generating section 3 on the right side is used on printing in the left direction and the heat generating section 3 on the left side on printing in the right direction respectively at that time. Consequently, a resistance film for a heating element composed of Ta2N, Ta- SiO, etc., is shaped onto the substrate 1, to which glazed glass 2 is arranged, through sputtering, etc., and an electrode film consisting of Cr, Au, Al, Cu, etc., is formed similarly onto the resistance film. The heat generating sections 3, common electrodes C1, C2 and discrete electrode E1-En are formed by employing a photolithographic method. Lastly, protective films are formed at both end sections 6, thus completing a head.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial type thermal head used in a serial type printer, among thermal heads used in printers, facsimile machines, video printers, etc.

0002

2. Description of the Related Art A number of techniques have been developed regarding bidirectional printing methods for serial thermal printers. Among these, the following two printers have been proposed as techniques for realizing bidirectional printing by tilting the head. That is, the first printer uses two heads.

The second printer has two or more pieces of glazed glass arranged on one head substrate, and a row of heating elements arranged on each piece of glazed glass.

0004

However, conventional printers for realizing bidirectional printing have had the following problems.

(1) In the first printer, which uses multiple (generally two) thermal heads and switches between right-hand printing and left-hand printing, the cost of the thermal head is doubled, and the cost of other parts is doubled. For example, two heat sinks and flexible printing circuits (hereinafter referred to as FPCs) are required, resulting in an extremely high total cost.

(2) A second method in which two or more glazed glasses are arranged on one substrate, heating element rows are formed on each glazed glass, and the heating element rows used are switched in each left and right direction. An example of a printer is shown in FIG.

As can be seen from the figure, in such a conventional printer, connection terminal portions 20 must be formed corresponding to all 2n heating elements formed on the thermal head substrate. The pitch of the terminal section is generally 0.2m.
/m is required. Therefore, the width W of the head is W=(2n-1
)×P+2Cw+2Sw is required. Here, P is the pitch width of the individual electrodes E1 to E2n, and Cw is the common electrode C1, C
The width Sw is the space between the individual electrodes and the common electrode. This is substantially equivalent to the area required by two thermal heads. Therefore, like the first printer, the thermal head cost is extremely high, and the same goes for the FPC.

A first object of the present invention is to provide a serial type thermal head capable of bidirectional printing at low cost. A second object of the present invention is to provide a small, high-density, practical serial type thermal head capable of bidirectional printing.

[0009]

[Means for solving the problem] In order to achieve the above purpose,
The serial type thermal head according to the invention according to claim 1 is characterized in that it has a glazed glass with heat generating parts arranged near both left and right end surfaces of a substrate, and a connecting terminal part is provided in the center of the substrate. do. Furthermore, the invention according to claim 2 is as follows:
Each first dot, each second dot, . . . each nth dot on each of the left and right glazed glass of the heat generating portion is connected to each other by individual electrodes. Further, the invention according to claim 3 is characterized in that the FPC used for connecting each terminal has a multilayer wiring structure.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view showing an embodiment of a serial type thermal head according to the present invention. A glazed glass 2 is formed symmetrically near the end face of a heat-resistant insulating substrate, and a heat generating portion 3 is formed on the glazed glass. In the figure, the heat generating part on the right side is used when printing in the left direction, and the heat generating part on the left side is used when printing in the right direction.

FIG. 4 shows a state diagram of the printing seen from above. As shown in the figure, printing is performed by tilting the head around the center line as the center of rotation. By arranging the glazed glass as close to the end face as possible, it is possible to create an angle between the head and the printing surface P.

The head in this embodiment is constructed by forming a resistive film for a heating element such as Ta2N or Ta-SiO on a substrate 1 on which a glazed glass 2 is arranged by sputtering, and further forming an electrode film thereon in the same manner. Form. As the electrode film, Cr
, Au, Al, Cu, and alloys thereof. Thereafter, using a photolithography method, the heat generating part 3, common electrodes C1, C2, individual electrodes E1,...
, En. The heat generating section 3 is composed of n dots in one vertical row. Finally, a protective film is formed on both ends 6 to complete the head. Reference numeral 7 denotes a connection terminal provided at the center, which is connected to an FPC or the like via solder or various conductive pastes. The corresponding dots of the left and right heat generating parts, that is, each first dot, each second dot, ... each nth dot, are
They are connected by individual electrodes E1, E2, . . . En. As a result, all conduction can be achieved by connecting (n+2) locations using the FPC shown in FIG.

[0013] The left and right dots are switched by common electrode C1,
It is sufficient to change C2 by switching. This FPC
As shown in the sectional view in FIG. 3, it has a multilayer electrode structure, and the corresponding upper and lower patterns are electrically connected through the through holes 10. In Figure 2, the connection terminal section 7 of the thermal head
The patterns that are conductively bonded are C1', E1', ..., E.
n' and C2', and the upper surface side patterns connected to each through hole 10 are C1", E1", and E2".
,..., En'', C2''. An insulating layer 11 made of polyimide, polyester terephthalate, etc. is provided between the upper and lower layer patterns. In reality, after the thermal head and FPC are mounted using solder or the like, epoxy adhesive is poured into the gaps between the patterns to increase strength. Although a thin film type thermal head has been described so far, the same method can be applied to a so-called thick film type thermal head.

As described above, the heat generating parts 3, 3 are arranged symmetrically on the left and right glazed glasses 2, 2, and the connection terminal part 7 is provided in the center of the board, and the corresponding 1st dot to nth dot By creating a thermal head with a structure in which dots are connected by individual electrodes E1, E2, . Compared to the conventional example in FIG.
We were able to reduce the area ratio by approximately 40%. Furthermore, by making the FPC to be connected to have a multilayer structure, it is possible to downsize and increase the density of the mounting section.

[0015]

[Effects of the Invention] According to the present invention, a small and high-density head is manufactured by providing a connection terminal section in the center of the thermal head substrate and connecting the corresponding left and right dots with one individual electrode. This makes it possible to perform mass production at a lower cost.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of a serial type thermal head of the present invention.

FIG. 2 is a configuration diagram of an FPC used for mounting the serial type thermal head same as above.

[Figure 3] Cross-sectional view of the thermal head and FPC mounted (
FIG. 1 (■-■ cross-sectional view)

FIG. 4 is a top view of the head of the present invention during printing.

FIG. 5 is a plan view of a conventional serial type thermal head for bidirectional printing.

[Explanation of symbols]

1 Heat-resistant insulating substrate 2 Glazed glass 3 Heat-generating parts C1, C2 Common electrodes E1, E2,...En Individual electrodes 6 Protective film forming part 7 Connection terminal parts E1" to En" FPC top surface individual electrodes C1", C2"
FPC top common electrode 10 Through hole 11 FPC insulating resin layer 12 FPC overcoat resin layer 13 Heat sink

Claims (3)

[Claims] 1. A heat-resistant insulating substrate, glazed glass formed near both left and right end surfaces of this substrate, a heat generating section formed on this glazed glass, and a connecting terminal section provided at the center of the substrate. Serial type thermal head equipped with. 2. The serial type thermal head according to claim 1, wherein each dot of the heat generating portion formed on both the glazed glasses is connected to each other by individual electrodes corresponding to the left and right sides. 3. The serial type thermal head according to claim 1, wherein the flexible printing circuit used for connecting each terminal of the connection terminal section has a multilayer wiring structure.