JPH0541799U - Structure of thermal print head - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Suppression of warpage caused by bimetal phenomenon
A thermal print head that enables a compact design without requiring a drive IC element protection cover. A terminal connecting means (5) electrically connects a main board (3) and a circuit board (4) to each other so that a connection terminal (9) on the main board (3) and a conductive connection portion (10) on the circuit board (4) face each other. The circuit board 4 is configured to maintain the connection and presses the circuit board 4 against the main board 3 at the overlapping portion of the connection terminal 9 on the main board 3 and the conductive connection portion 10 on the circuit board 4. The periphery of the driving IC element 8 is covered with a hard type resin in order to protect the driving IC element 8 which is composed of the leaf spring member 12 and is arranged on the main substrate 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention comprises a main board having a heating resistor, a driving IC element, a connection terminal, and the like, and a flexible circuit board having an external connection terminal. The main board and the flexible circuit board are connected to each other on the main board. In a thermal print head that is electrically connected via terminals and a conductive connection portion of a flexible circuit board, especially, a driving IC element is covered with a hard type resin, and a leaf spring member is used. The present invention relates to a thermal print head having a novel structure in which a main board and a circuit board are pressed into contact with each other to electrically connect the connecting portions.

[0002]

[Prior Art]

 As is well known, the conventional thermal print head 21, as shown in FIG. 3 and FIG. 4, has a radiator plate 22, a heating resistor 26, a common electrode 27, a driving IC element 28, a connection terminal 29, and the like. A board 23, a conductive circuit portion 30, a flexible circuit board 24 having external connection terminals (connectors) 31, a drive IC element protection cover 25 for protecting the drive IC element, and a plurality of tightening screws 32. The connection terminal 29 on the main board 23 and the conductive connection portion 30 on the flexible circuit board 24 are electrically connected to each other and assembled. In the conventional thermal print head 21, the drive IC element protection cover 25, the flexible circuit board 24, the main board 23, and the heat dissipation plate 22 that are stacked are assembled by a plurality of tightening screw screws 32. The electric connection between the board 23 and the flexible circuit board 24 is made by pressing the elastic member 33 such as silicon rubber attached to the driving IC element protection cover 25 by elastic force by screwing. It is designed to remain connected. The electrical connection means between the main board 23 and the flexible circuit board 24 in the conventional thermal print head 21 having the above-mentioned structure protects the driving IC element 28 by pressing connection with a plurality of tightening screws 32. Since the drive IC element protection cover 25 and the heat dissipation plate 22 attached to the bottom surface side of the main board 23 are directly fixed to each other, when the temperature of the heating resistor 26 on the main board 23 rises, When the thermal expansion causes the driving IC element protection cover 25 to be unable to follow the thermal expansion, a so-called bimetal phenomenon causes warpage in the longitudinal direction of the thermal print head. When used as a thermal print head, this sled has a serious drawback that uneven printing pressure is applied to the printing paper, resulting in a marked deterioration of printing quality.

[0003]

[Problems to be solved by the device]

 Therefore, the present invention is intended to solve the above-mentioned drawbacks and problems found in the conventional thermal print heads. As a means for electrically connecting the parts to each other in a superposed manner, a pressing connection structure using a combination of leaf springs is used to suppress warpage due to the bimetal phenomenon seen in the conventional thermal print head described above. It is intended to provide such a thermal print head. Further, the present invention uses a hard type resin as a means for protecting the driving IC element, and thus does not require the driving IC element protection cover found in the conventional thermal print heads described above, and is extremely compact. The present invention aims to provide a thermal print head that enables various designs.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention is specifically to fix a heat dissipation plate and the heat dissipation plate so as to be superposed on each other via a first surface, and a heating resistor on the second surface. A common electrode that is commonly conducted to the heating resistor, an individual electrode that is individually conducted to the heating resistor, a plurality of driving IC elements that are respectively connected to the individual electrodes and drive the heating resistor, the drive A main board having connection terminals respectively connected to the IC elements for use, a first surface, a conductive connection portion corresponding to each connection terminal on the main board, and a conductive connection portion respectively connected to the conductive connection portion. A flexible circuit board having external connection terminals, connection terminals on the main board, and conductive connection portions on the circuit board facing each other and overlapping to form a terminal connection means for maintaining electrical connection. In a thermal print head configured by, in order to protect the drive IC element on the main substrate, the periphery of the drive IC element is covered with a hard type resin, and the terminal connecting means comprises: The circuit board is combined with the second surface side of the circuit board so as to press the circuit board against the main board at the overlapping portion of the connection terminal of the main board and the conductive connection portion of the circuit board. A thermal print head composed of leaf spring members is constructed.

[0006]

[Explanation of Examples]

 Hereinafter, the structure of the thermal print head according to the present invention will be described in detail with reference to a concrete embodiment shown in the drawings. FIG. 1 is a schematic perspective view showing an example of the structure of the thermal print head according to the present invention, which is disassembled in the assembling direction, and FIG. is there. As shown in FIGS. 1 and 2, the thermal print head 1 according to the present invention basically comprises a heat dissipation plate 2, a main board 3, a circuit board 4 and a terminal connecting means 5. In this invention, the main substrate 3 has a length L substantially the same as that of the heat dissipation plate 2, and is superposed on the heat dissipation plate 2 via the first surface 3a. A heating resistor 6 extending along the lengthwise direction of the first surface 3b, a common electrode 7 commonly conducting to the heating resistor 6 and an individual electrode individually conducting to the heating resistor 6 ( (Not shown), a plurality of driving IC elements 8 each connected to the individual electrode and driving the heating resistor 6, and connection terminals 9 each connected to the driving IC element 8. It consists of In this invention, the drive IC element 8 on the main substrate 3 is covered with a hard type resin 17 for the purpose of protection. The circuit board 4 is provided with conductive connection portions 10 that are respectively connected to the respective connection terminals 9 on the main board 3 on the first surface 4a, and also provided with external connection terminals (connectors) 11. It consists of things.

On the other hand, in this invention, the terminal connecting means 5 makes the connection terminals 9 on the main board 3 and the conductive connection portions 10 on the circuit board 4 face each other and overlap each other to establish an electrical connection. This is for maintaining, and the circuit board 4 is pressed against the main board 3 at the overlapping portion P 1 of the connection terminal 9 on the main board 3 and the conductive connection portion 10 on the circuit board 4. It is constituted by a leaf spring member 12 and two tightening screws 13, 13 which are combined with each other on the side of the second surface 4b of the circuit board 4 for biasing. The leaf spring member 12 is provided with two screw insertion holes 14 and 14, and the circuit board 4 is provided with two screw insertion holes 15 and 15 corresponding to the two screw insertion holes 14 and 14, respectively. The heat radiating plate 2 is provided with two screw holes 16 and 16 corresponding to the above-mentioned screw insertion holes, and is assembled by the tightening screw 13 as shown in FIG. Is becoming By assembling as described above, the circuit board 4 is pressed against the main board 3, and the connection terminals 9 of the main board 3 and the conductive connection portions 10 of the circuit board 4 are superposed. Electrical connection is maintained at each part.

[0008]

[Effect of the device]

 The thermal printhead of the present invention having the above-mentioned configuration is used as a means for electrically connecting the main board and the circuit board by superposing the connecting terminals on the main board and the conductive connecting portions on the flexible circuit board. Applying a pressing connection structure by a combination of leaf springs, this is applied only to the overlapping portion of the connection terminal on the main board and the conductive connection part on the circuit board, and the circuit board is applied to the main board. Since it is biased against the pressure, it is possible to suppress the occurrence of warpage due to the bimetal phenomenon found in conventional thermal printheads, and it can be said that it is extremely effective in improving print quality. Further, the thermal print head according to the present invention does not require the drive IC element protection cover that is recognized in the conventional thermal print head because the hard type resin is used as the means for protecting the drive IC element. It can be said that it is extremely effective in that it can be designed very compactly.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a structural example of a thermal print head according to the present invention, showing a state in which the thermal print head is disassembled in an assembling direction.

FIG. 2 is a cross-sectional view of the thermal print head in an assembled state.

FIG. 3 is a schematic perspective view showing a state in which the thermal print head is disassembled in an assembling direction in a structural example of a conventional thermal print head.

FIG. 4 is a cross-sectional view of a conventional thermal print head in an assembled state.

[Explanation of symbols]

 1 Thermal Print Head 2 Heat Sink 3 Main Board 4 Circuit Board 5 Terminal Connection Means 6 Heating Resistor 7 Common Electrode 8 Driving IC Element 9 Connection Terminal 10 Conductive Connection Section 11 External Connection Terminal 12 Leaf Spring Member 13 Tightening Screw 17 Hard Type resin

Claims (1)

[Scope of utility model registration request] 1. A heat radiating plate, a common electrode fixed to the heat radiating plate in an overlapping manner via a first surface, and a heating resistor on the second surface, and a common electrode commonly conducting to the heating resistor. An individual electrode electrically connected to the heating resistor, a plurality of driving IC elements connected to the individual electrode to drive the heating resistor, and connection terminals respectively connected to the driving IC elements. A main circuit board, and a flexible circuit board having, on the first surface, conductive connection portions respectively corresponding to the connection terminals of the main circuit board, and external connection terminals respectively connected to the conductive connection portions; In a thermal print head constituted by a connection terminal on the main board and a terminal connection means for maintaining an electrical connection by making conductive connection portions of the circuit board face each other and overlapping each other, In order to protect the drive IC element on the main board, the periphery of the drive IC element is covered with a hard type resin, and the terminal connecting means is a connection terminal on the main board.
A leaf spring member combined with the second surface side of the circuit board so as to press and urge the circuit board against the main board at a position where the conductive connection portion of the circuit board is superposed. The structure of the thermal print head.