JPH08132659A - Thermal head - Google Patents

Abstract

PURPOSE: To provide a low-cost thermal head in which mounting of a head board on a base is facilitated and which has excellent operability in the head having the head board formed with heating recording element rows and a hard printed board for supplying power and a signal to the head board. CONSTITUTION: A positioning raised part 101 for deciding the position of a head board 11 is provided on a base 10. A connecting terminal group formed on the board 11 is conductively connected to a connecting terminal group formed on the board 12 by a flexible board 13, a pectinated board or a crosslinked board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used in a thermal recording device or the like, and more particularly to a head substrate arranged on a heat sink base and a printed circuit board for supplying signals and electric power to the head substrate. The present invention relates to a type of thermal head that is combined with.

[0002]

2. Description of the Related Art As a general structure of a conventional thermal head of this type, this type of thermal head is usually attached to a thermal recording apparatus or the like with a heat radiating plate base (hereinafter, simply referred to as a base) as a reference. Therefore, it was necessary to position the thermal head at an appropriate position with respect to the base. Therefore, conventionally, both jigs have been fixed with screws or double-sided adhesive tape. The main electrical connection method to the head substrate mounted on the base in this way is as follows: (1) A flexible resin such as polyimide having a connection terminal group matching the connection terminal group of the head substrate is used as a base. A flexible printed circuit board, and the connection terminal group of the head circuit board and the connection terminal group of the flexible printed circuit board are superposed and connected by pressure welding or an anisotropic conductive adhesive, (1) on the base A configuration in which a head printed circuit board and a hard printed circuit board such as a glass epoxy having a connection terminal group that matches the connection terminal group of the head circuit board are closely arranged, and the corresponding connection terminals of both connection terminal groups are connected by wire bonding,
Etc.

[0003]

First, there is a drawback that the adjustment work for increasing the accuracy of mounting the thermal head on the base becomes large. Also, the two are firmly joined by being screwed or fixed with double-sided adhesive tape, etc., and the so-called bimetal effect occurs between the two due to the heat generated by the thermal head itself, and the thermal head warps (the thermal head bends). ) Had the drawback of doing so. Further, regarding the electrical connection method, the former method using a flexible printed circuit board has a drawback that the flexible printed circuit board is expensive. Further, in the case where this flexible printed circuit board is pressure-contacted to the head substrate, there is no choice but to adopt a structure in which the flexible printed circuit board, the head substrate, and the heat dissipation plate base are pressed against each other. There is a drawback that they are strongly coupled in the stacking direction, and if the thermal expansion coefficients of the respective members are not the same, the bimetal effect becomes large and the thermal head may warp as in the above case. Furthermore, in the case where the flexible printed circuit board is conductively connected to the head substrate by using an anisotropic conductive adhesive, the operation check of the thermal head substrate is in a state close to a completed state after completion of the adhesion. For example, even if a minor defect is found at this stage, it is difficult to repair it, and the expensive flexible printed circuit board that is bonded must be discarded. It had the drawback of not having it. On the other hand, if the latter hard printed circuit board is used and the head circuit board and the hard printed circuit board are conductively connected by wire bonding, the operation of the thermal head must be checked in a state close to the completed state after completion of wire bonding. In addition, it has a drawback that it is difficult to rework when a defect is found. The present invention has been made in view of these points, and provides a thermal head that can easily attach a head substrate to a base, is inexpensive, and can be relatively easily reworked to reduce heat shaving and the like. It is intended for.

[0004]

Therefore, in the present invention, a base, a head substrate attached to the base, and a printed circuit board for supplying a signal or power to the head substrate are combined. In the configured thermal head, a head positioning convex portion composed of a projecting portion is provided on one long side end portion of the base, and a heating element row is provided on one long side end portion of the head substrate on the other side. A connecting terminal group for connecting to the printed board for supplying electric power to the heating element array is provided on the long side end portion of the head substrate, and the head substrate is provided on the positioning projection of the long side end portion on one side of the base. A thermal head was constructed by abutting the long side edges on one side.

[0005]

Since the head substrate is mounted in contact with the head positioning convex portion of the base, the position adjustment of the head substrate is simplified, and the fixing method does not require a strong fixing method, so that the factors such as thermal warpage can be prevented. Can be made smaller.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to one embodiment of the drawings. Here, FIG. 1 is a configuration perspective view of a thermal head according to the present invention, FIG. 2 is a side view of the thermal head shown in FIG. 1, and FIG. 3 is an example of a flexible printed circuit board as a connection board. FIG. 4 is a configuration perspective view showing an example of a bridging substrate as a connection substrate, and FIG. 5 is an explanatory diagram showing another example of a connection substrate. In each drawing, 10 is a base that also serves as a heat dissipation plate made of an aluminum material, 11 is a head substrate, 12 is a hard printed circuit board,
Reference numeral 13 is a flexible printed board as a connection board, 14 is a cover, 15 is a seal, 2 is a platen of the recording apparatus, and 3 is a thermal recording medium. In the following description, a rigid printed board will be referred to as a "printed board", and a flexible printed board will be referred to as a "flexible board".

First, a thermal head according to an embodiment of the present invention will be described with reference to FIGS. The base 10 has a head positioning convex portion 101 formed of a protruding portion formed on one long side end portion thereof and a printed circuit board (PCB) positioning convex portion 102 formed of a protruding portion parallel to the head positioning convex portion. ing. This PCB positioning convex portion 102
And the head positioning convex portion 101 are the head substrate 1 described later.
The width is larger than the width of 1, and the head substrate 11 is arranged between them. The head substrate 11 made of a ceramic substrate or the like is held in a state where one long side end portion of the head substrate 11 is in contact with the head positioning convex portion 101. The printed circuit board 12 is attached so that the long side edges are in contact with the rising portions on the outside of the PCB positioning convex portion 102. In this case, as shown in FIG. 2, when the platen 2 is rotated clockwise to draw a desired image, one side of the long side of the head substrate 11 has a head positioning convex portion. Since the head substrate 11 is in contact with the rising portion of the inside of the substrate 101, even if the head substrate 11 is not firmly attached, the head substrate 11 is not displaced.

On the head substrate 11, a drive IC 112 and a diode array 113 are sequentially arranged at predetermined positions. Further, on the head substrate 11, a heat generating resistor 111 that generates heat due to these effects and the heat generating resistor 111.
A group of electrodes traversing the heating resistor and a group of connection terminals (collectively referred to as a wiring pattern) for receiving an external signal are formed by printing or the like in order to perform predetermined recording on the. The electrical connection between them is made by wire bonding or the like. As shown in FIG. 1, the connection terminal group of each of these wiring patterns is formed on the other long side end portion of the head substrate 11.

On the other hand, a connection terminal group corresponding to the connection terminal group formed on the head substrate 11 is printed and formed on one long side end portion on one side of the printed circuit board 12. Although not shown, a predetermined wiring pattern is formed together with this connection terminal group, and signals and power are supplied from the outside via the connector 122.

That is, as shown in FIG.
The head substrate 11 is sandwiched between the PCB positioning convex portions 102 of
The long side edge portion on the other side and the long side edge portion on the one side of the printed circuit board 12 are arranged to face each other. In the apparatus of this embodiment, the head substrate 11 and the printed circuit board 1 are
The upper surfaces of the two are held so that they have almost the same height.

Now, the connection terminal group formed on the other long side edge portion of the head substrate 11 and the corresponding connection terminal group formed on one long side edge portion of the printed board 12 are connected. As the connection board, for example, the connection flexible board 13 shown in FIG. 3 is used. This connection flexible substrate 13
Are the head substrate 11 and the printed circuit board 12 that are arranged opposite to each other.
It has a conductor pattern 131 for connecting the connection terminals. The flexible substrate 13 is shown in FIG.
It is attached to the position shown in FIG. 2 by an anisotropic conductive adhesive or anisotropic conductive tape (not shown).

In this thermal head, as shown in FIG. 2, the connecting portion between the head substrate 11 and the printed substrate 12, the drive IC 112, the diode array 113.
The cover 1 is provided in order to seal the part and to secure a transfer path for the heat-sensitive medium 3 and to prevent adverse effects such as dust.
4 is provided.

In connecting the head substrate 11 and the printed circuit board 12, a bridging substrate 13 as shown in FIG. 4 may be used instead of the connection flexible substrate as shown in FIG. In this embodiment, the bridge substrate 13 is made to have the same flexibility as a flexible substrate. Since the conductor portion (foot) that is adhesively fixed to each connection terminal is configured separately, it is possible to deal with expansion of each portion due to heat of the thermal head with a certain degree of freedom. Further, for the same reason, instead of such a cross-linked structure, a connection member (FIG. 5) simply formed in a comb shape may be used.

Although the method for fixing the base 10 and the head substrate 11 to each other has not been described in the above-mentioned respective embodiments, the both are attached by applying grease to the surface of the mounting portion of the head substrate 11 of the base 10. By coating, the back surface of the head substrate 11 can be brought into a close contact state. The position of the head substrate 11 is fixed and held by the head positioning protrusion 101 of the base, the adhesiveness of grease, the pressing of the platen 2, and the like.

Further, in this case, instead of such an attaching method, only the central portion of the head substrate 11 in the longitudinal direction is attached to the base 10 by using the double-sided tape, and the printed substrate 12 is attached in the vicinity of the central portion in the longitudinal direction. It may be fixedly attached to the base 10 with a screw or the like. In any case, the base 10 and each of the substrates 11 and 12 are configured to be slidable with respect to each other, at least in the longitudinal direction, unlike the conventional ordinary thermal head.
As a result, even if the thermal expansion coefficient of the base 10 is different from that of each of the substrates 11 and 12, the bimetal effect can be reduced, and the heat deflection of the thermal head can be reduced.

Although the driving IC 112 and the diode array 113 are mounted on the head substrate 11 in the above embodiment, these integrated circuits may be mounted on the printed circuit board 12 respectively. Good.
In this case, the connecting portion is the heating resistor 1 on the head substrate 11.
Each side electrode traversing 11 and the connection terminal group of the printed board are conductively connected by the connection board.

[0017]

As described above, the present invention has the following effects. The base and the head substrate can be easily attached, and the cause of thermal warpage can be reduced without adopting a strong fixing method. Further, for example, the portion using the expensive flexible substrate can be only the connecting portion between the head substrate and the printed circuit board, and the cost can be reduced. Further, in this case, by using a bridging substrate or a comb-shaped substrate as the connecting substrate for connecting the above-mentioned connecting portions, even when the respective parts expand due to heat from the thermal head, the conductive portion (foot) of the bridging substrate or the comb-shaped substrate ) Can deal with it freely.

[Brief description of drawings]

FIG. 1 is a configuration perspective view of a thermal head showing one embodiment of the present invention.

FIG. 2 is a side view of the thermal head shown in FIG.

FIG. 3 is a structural explanatory view showing an example of the connection board of FIG.

FIG. 4 is a configuration perspective view showing another example of the connection board.

FIG. 5 is a configuration explanatory diagram showing another example of the connection board.

[Explanation of symbols]

10: Heat sink base 11: Head substrate 12: Printed circuit board 13: Connection board

Claims (3)

[Claims] 1. A thermal head comprising a base, a head substrate attached to the base, and a printed circuit board for supplying a signal or electric power to the head substrate. A head positioning convex portion formed of a protruding portion is provided on the long side end side of the heating element array, and the heating element array is provided on the long side end side section on one side of the head substrate and the heating element array is provided on the other side of the long side end section. A connection terminal group for connecting to the printed circuit board is provided to supply electric power, and the long side edge portion on one side of the head substrate is brought into contact with the positioning convex portion on the long side edge portion on one side of the base. The thermal head is characterized by comprising a thermal head. 2. A printed circuit board positioning convex portion formed of a protruding portion parallel to the head positioning convex portion is provided at a predetermined position of the base, and the printed circuit board positioning convex portion has a long side edge on one side of the printed circuit board. The connection terminal group of the head substrate and the connection terminal group of the printed circuit board are arranged so as to oppose each other with the printed circuit board positioning convex portion sandwiched therebetween. The thermal head according to claim 1, further comprising: a connection board that conductively connects to a connection terminal group of the printed board. 3. A hard printed board made of glass epoxy or the like is used as the printed board, and a flexible board made of polyimide or the like, a bridged board or a comb-like board is used as the connection board. The thermal head according to claim 2.