JPS62238760A - Thermal head - Google Patents

Abstract

PURPOSE:To provide a small and low cost thermal head excellent in thermal response and fast printing by inserting a second ceramic substrate between a thermal head substrate equipped with a circuit board and an array of thermal resistors and mounting a drive IC for driving the array of thermal resistors on the wiring board. CONSTITUTION:A thermal head substrate 1 equipped with an array of thermal resistors on a partial glazed part 2 is arranged and fixed on a second ceramic substrate 4 together with a circuit board consisting of monowiring or multiwiring. The ceramic substrate 4 is fixed on a radiator plate 5. A drive IC 6 is directly mounted on the circuit board 3, and the drive IC 6 is electrically connected to the thermal head substrate 1 and the circuit board 3 using a bonding wire 7. Thus it is possible to miniaturize a thermal head under production and minimize a required space for costly thermal head substrate. Consequently the thermal head becomes excellent in high thermal response and is of small size and less expensive.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of a thermal head, and in particular, an object of the present invention is to provide a thermal head that has excellent thermal response characteristics, is suitable for high-speed printing, and is small and low-profile. be.

[Conventional technology]

Conventionally, this type of thermal head is made of alumina.

Partial glaze, full-scale glaze, etc. are applied as a heat storage layer on a ceramic substrate such as enamel or silicon carbide, and furthermore, heating resistor arrays and conductors made of a thin film-like substance or a thin film-like substance, etc. are formed on the substrate. , if desired, a drive IC'' 41 for driving the heating resistor array on this substrate is mounted or connected as a thermal head substrate. This thermal head substrate is fixed on a heat sink and used as a thermal head. In order to improve the thermal response characteristics of the thermal head, one possible method is to insert, for example, a second ceramic substrate between the thermal head substrate and the heat sink.

[Problem that the invention seeks to solve]

As an example of mounting a drive IC in the conventional thermal head described above, 1, for example, a drive IC is mounted directly on a thermal head substrate equipped with a heating resistor, and the electrodes in the drive IC are connected by wire bonding, solder bump melting, etc. There is one that electrically connects the conductor on the thermal head substrate.

however.

This, 1! tT's thermal head requires a large area to mount the IC on the thermal head substrate, and therefore the area of the expensive thermal head substrate that requires a complicated manufacturing process is large. It has the drawback of being expensive.

In addition, as a second example of mounting a drive IC, for example, as described in Japanese Patent Application No. 59-28045, it is possible to reduce the area of the thermal head substrate by removing the IC from the thermal head substrate. A multilayer wiring board (for example, a printed board) is arranged and fixed in a plane at 5 with a constant gap.

There is a method of arranging a large number of drive ICs in this gap. In this case, a wiring conductor formed on a heat-resistant film such as polyimide is soldered to an electrode in a drive IC, a semiconductor on a thermal head substrate, a conductor in a multilayer interconnection 1ls4Ii, etc. Connect by thermocompression bonding method (TAB method) etc.
It electrically connects the drive IC, thermal head board, and multilayer wiring board. However, this type of thermal head does not have power in the gap between the thermal head board and the wiring board.
Due to the arrangement of Ic, the dimensions of the manufactured thermal head are large (there is a disadvantage), and expensive polyimide film etc. are used.

Thermal heads also have the disadvantage of being expensive.

[Means for solving problems]

In the thermal head of the present invention, the second ceramic substrate inserted between the thermal head substrate and the heat sink is extended and also provided under 71 of the wiring board.

Moreover, an interlocking IC is mounted on the wiring board.

〔Example〕

Next, one embodiment of the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram schematically showing a sectional view of a main part of an embodiment of the present invention, and FIG. 2 is a plan view of FIG. 1.

Reference numeral 1 denotes a thermal head substrate having a zero row of heating resistors in a partial glaze 2 portion, and is placed and fixed on a second ceramic substrate 4 together with a wiring board 3 having a single layer gap A or multilayer wiring. This ceramic substrate 4 is further fixed on a heat sink 5. The drive IC 6 is mounted directly on the wiring board 3. Electrical connections between the drive IC, the thermal head substrate, and the wiring board are made by bonding wires 7.

〔Effect of the invention〕

As explained above, the present invention extends the second ceramic &4 inserted between the thermal head substrate and the heat sink to the wiring board 30'F, and furthermore, the drive I
By installing C.

Along with making the thermal heads manufactured smaller.

This reduces the area required for an expensive thermal head board. Therefore, the thermal head according to the present invention has excellent thermal response characteristics, is small in size, and is inexpensive.

Since the present invention exhibits the above-described effects, the material and thickness of the thermal head substrate, ceramic substrate, wiring board, heat sink, etc.
Fixing method, shape, resolution of the manufactured thermal head,
It goes without saying that there are no particular limitations on the dimensions of the application, the number of ICs mounted, etc. Therefore, (for example, the thermal head substrate 1 having a partial brace or a full glaze disposed on the second ceramic plate 4 and the single layer or multilayer wiring board 3 are movably bonded to the ceramic plate using a soft resin such as silicone resin. It goes without saying that it may be in contact with the substrate 4 (or it may be fixed in an immovable state by mechanical means such as Φ epoxy resin or screws with high thermal conductivity).

Furthermore, it goes without saying that the relative positional relationship of the thermal head substrate, wiring board, heat sink, etc. should not be specified as a matter of course. There are no particular restrictions on the connection method between the Yu-controller/auxiliary IC, thermal head board, and wiring board, and the drive I/O
Section C is generally sealed with silicone resin or the like.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing the main parts of the present invention. FIG. fi2 is a schematic plan view of FIG. 1. l...Thermal head board, 2...Partial glaze, 3...Wiring board, 4...Second setup Jli&. 5... Heat sink, 6... Drive 11:, 7
...bonding wire.

Claims (1)

[Claims] A second ceramic substrate is inserted between a thermal head substrate including a wiring board and a heat generating resistor array and a heat sink, and a driving IC for driving the heat generating resistor array is mounted on the wiring board. Thermal head is characterized by: