JP2600700Y2 - Thermal head - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a thermal head,
In particular, the present invention relates to an improvement for making it possible to easily inspect the operation of a driving IC of a heating resistor for performing printing in a thermal head.

[0002]

2. Description of the Related Art In a conventional thermal head, a plurality of heating resistor driving ICs are connected in a cascade, and input signals are sequentially transmitted as they are from a first stage IC to a last stage IC. I have. In this case, the output signal of the final stage IC is normally held as it is, and is not supplied to other components, and is usually left as it is.

[0003]

However, in the conventional thermal head having such a configuration, it is necessary to determine whether or not the input data signal is normally transmitted to the IC at each stage by using the head. In addition to actually printing, there was a disadvantage that it took too much time to find a defective head during the manufacturing process.

An object of the present invention is to make it easier to find a defective head by inspecting the output signal of the last-stage IC in order to improve the drawbacks of the conventional thermal head.

[0005]

In order to achieve the above object, the present invention provides a thermal head having a plurality of stages of heating resistor driving ICs connected in cascade on a wiring board for signal input to the ICs. An inspection pad is provided, and an output terminal of the IC at the last stage is connected to the pad so that the quality of an output signal from the output terminal can be inspected.
Of the head cover
The point is that holes are provided in the cover.

[0006]

In the thermal head according to the present invention, the signal from the test pad is checked to determine the I
It can be easily checked whether the signal is normally transmitted to C.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention shown in the drawings will be described below. FIG. 1 is a schematic structural view of a thermal head according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a heat radiating plate usually made of aluminum, on which a ceramic substrate 3 made of alumina provided with an electrode, a heating resistor 2, an IC for driving a heating resistor, and the like is adhered. An input line from a signal input wiring board (FPC) 4 is collectively soldered to an input terminal portion of the board 3. Reference numeral 5 denotes a cover for protecting the IC and the solder connection portion, 6 denotes an IC sealing resin, 7 denotes a chip type multilayer ceramic capacitor, and 8 denotes a connector.

As shown in FIG. 2, R1 to R320 are provided on the ceramic substrate 3 as the heating resistor 2.
Further, these heating resistor driving ICs IC1 to ICn are provided.

On the signal input FPC 4, input lines L for the heating resistor 2 and the IC, capacitors C1 and C2 indicated by the ceramic capacitor 7 and the like, and an inverter I
An NV, a thermistor TH, and an inspection pad 9 are provided. The terminal TP of the inspection pad 9 is connected to the output terminal DO of IC1, which is the last stage IC among the cascaded ICs.

After completion of the IC mounting (wire bonding), whether or not the data signal is normally transmitted to the ICs of the respective stages can be inspected by, for example, checking the inspection pad 9 with an oscilloscope. As a result, if it is found that the data signal is not transmitted normally, the oscilloscope further hits the ceramic substrate 3 to identify the defective IC, removes the defective IC in some cases, and replaces the new IC again. Implement.

Further, by performing the same inspection even after the batch soldering of the FPC is completed, a defective IC can be found without performing an actual printing test. FIG. 3 shows another embodiment of the present invention, in which a predetermined portion A of the FPC 4 is bent to form a low-profile thermal head.

FIGS. 4 (a) and 4 (b) show still another embodiment of the present invention. FIG. 4 (a) shows a thermal head cover 5 mounted.
State, (b) shows a state in which the cover removed 5.
As shown in FIG. 4 (a), the cover 5, the inspection hole 10 is provided in a portion corresponding to the inspection bad 9.

With this configuration, the operation of the IC can be checked through the inspection hole 10 while the cover 5 is left, so that the method of finding the defect of the IC is simplified, and the time required for the check can be further reduced. Become.

[0014]

As described above, according to the thermal head of the present invention, it is possible to check the operation of the heating resistor driving IC before actually performing printing.
The method for finding the defect of C is simplified, and the time required for the check can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 shows a thermal head body and an F in the embodiment.
FIG. 3 is a circuit configuration diagram of a PC unit.

FIG. 3 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 4 is a schematic view showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat sink 2 Heating resistor 3 Ceramic board 4 FPC 9 Inspection pad 10 Inspection hole

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/345 B41J 2/35

Claims (1)

(57) [Scope of request for utility model registration] 1. A thermal head having a plurality of stages of heating resistor driving ICs connected in cascade, wherein a test pad is provided on a signal input wiring board for the IC, and an output terminal of the final stage IC is connected to the IC. Connected to the pad so as to be able to inspect the quality of an output signal from the output terminal, and connecting the inspection pad to the signal input wiring
The pad provided at a position hidden by the cover of the substrate head
Thermal head characterized by having holes in the upper cover
De.