JPH0566870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field This invention relates to a method for manufacturing a thermal head.

(b) Conventional technology When manufacturing a thermal head used in a thermal transfer type or thermal paper type printer, first a thermal head original plate is manufactured by forming various electrodes and heating resistors on an insulating substrate, and then this original plate is Individual thermal heads are manufactured by dividing each thermal head into regions corresponding to each individual thermal head.

When individual thermal heads are separated from the thermal head original plate in this way, burrs, chips, etc. occur on the cut surfaces of each thermal head, which interferes with the running of the thermal transfer ribbon when installed in a printer, etc., and adversely affects printing quality. There were times when I gave. Conventionally, one method to improve this problem was to divide each thermal head from a thermal head original plate into larger dimensions in advance, and then grind the end face of the substrate by a predetermined amount using a grinding tool to finish it. We are hiring.

FIG. 2A shows a vertical cross section of a single thermal head that has been divided. For example, the end surface of the substrate 1 before grinding is D, and by grinding this end surface a certain amount to the position shown in C. burrs on the edge of the board,
We are making corrections to chips, etc., and to the external dimensions.

(c) Problems to be Solved by the Invention In such a conventional method for manufacturing a thermal head, when grinding the edge of the substrate, the outer edge of the substrate is used as a reference. Due to the presence of burrs and chips, the external dimensions after correction will vary due to this influence. In addition, for example, if a grinding wheel is used as an abrasive material, the grinding performance will vary greatly depending on the surface condition such as clogging of the grinding wheel, and with fixed size and constant speed feed, the difference in the amount of grinding due to the surface condition cannot be fed back to the feed amount of the grinding wheel. Therefore, the quality of the finished surface cannot be improved.
Note that if the amount of grinding is controlled based on the electrode pattern shown in A-B in FIG. There was a problem in that it was not possible to perform grinding and grinding at the same time, reducing manufacturing efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a thermal head in which the amount of grinding is controlled based on the conductor pattern and measurement and grinding can be performed simultaneously to improve manufacturing efficiency.

(d) Means for Solving the Problems The method for manufacturing a thermal head of the present invention includes providing a conductor film for inspection between a heat generating part on a substrate of a thermal head and an edge of the substrate near the heat generating part; While inwardly grinding the end surface of the substrate near the heat generating part with a conductive grinding tool, the electrical resistance value between the inspection conductor film and the grinding tool was measured, and this resistance value reached a predetermined value. It is characterized by finishing the grinding when.

(e) Effect In the method for manufacturing a thermal head of the present invention, a conductive film for inspection is provided between the heat generating part on the substrate of the thermal head and the edge of the substrate near the heat generating part, so that conductive grinding is possible. By grinding the end surface of the substrate near the heat generating part inward with the tool, the area of the test conductor film changes, and the electrical resistance value between the grinding tool and the test conductor film changes accordingly. do. Therefore, by finishing the grinding when this resistance value reaches a predetermined value, it is possible to carry out the grinding to a predetermined position with respect to the test conductor film.

(f) Embodiment FIG. 1 is a conceptual diagram of a method for manufacturing a thermal head according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a substrate of a thermal head, on the upper surface of which an inspection electrode 10 and other electrodes are formed.A grinding wheel 22 is brought into contact with the end surface of the substrate 1 to be ground, and the end surface is ground. . The detection part 20 is the inspection electrode 10
This is a circuit that detects the electrical resistance value between the grinding wheel 22 and the grinding wheel 22, and the control section 21 controls the movement of the grinding wheel 22 according to the output signal of the detection section 20.

FIGS. 3 and 4 are diagrams showing the structure of the thermal head, with the upper part of FIG. 3 showing a longitudinal section and the lower part showing a plan view. Further, FIG. 4 shows in detail a longitudinal section near the end face on the side to be ground. In FIG. 4, reference numeral 1 denotes an insulating substrate such as alumina ceramics, and a semicircular glaze layer 2 is formed near the edge of the substrate 1, and resistor layers 3 and 4 are formed on the top of the substrate 1 and the glaze layer 2. are formed, upper metal layers 5, 6 and 7 are formed thereon, and the entire surface thereof is further covered with a protective film 8. As shown in FIG. 3, the metal layer 6 is used as a common electrode to commonly connect a plurality of resistor layers 3, and the metal layer 5 supplies a drive signal to the resistor layer 3 between the common electrode 6 and the metal layer 6. It is used as a lead electrode. Furthermore, the resistor layer 4 and the metal layer 7 above it are patterned between the end of the substrate near the heat generating part and the heat generating part, and are used as test electrodes, and are attached to the other end of the board as external connection terminals 7a. It's being pulled out. Such a thermal head is manufactured as follows.
First, after screen printing glaze 2 on the original plate and baking it, a resistor layer and a metal film such as Al are formed on the entire surface by sputtering, and a resist process and an etching process are performed twice to form the resistor layer.
Pattern the Al layer. Thereafter, a protective film is sputtered over the entire surface to produce a thermal head original plate, and the original plate is cut along a predetermined line to obtain individual thermal heads.

Thereafter, the end surface of the substrate is ground as shown in FIG. 1, but in FIG.
When it reaches this point and comes into contact with the inspection electrode 7, the resistance value decreases rapidly. Furthermore, when grinding down to L3, the contact area between the grinding wheel and the inspection electrode decreases, and the resistance value sharply increases accordingly. By detecting the decrease and increase in the resistance value in this way, it is possible to determine whether the grinding wheel is located at L1-L2, L2-L3, or inward from L3, and whether it is L2 or L3. This position can be finished as an end face.

Note that when grinding the edge surface of the substrate, it is not limited to grinding the side surface of the substrate in parallel as shown in Fig. 2A, but only on the sliding part of the thermal transfer ribbon as shown in Fig. It is also possible to perform edge shaping.

5 to 9 show electrode shapes of thermal heads according to other embodiments. The example shown in FIGS. 5 and 6 is an example in which a tapered inspection electrode 7 is formed between the heat generating part and the edge of the substrate, and in this case as well, there is a correspondence between the grinding position by the grinding wheel and the resistance value. By using this relationship, any position of the tapered portion can be finished as an end surface. FIG. 7 shows an example in which the inspection electrode 7 and the common electrode 6 are connected in common and are used partially. In this case, the same process as shown in FIG. 3 can be performed by measuring the resistance value between the common electrode and the grinding wheel. Figures 8 and 9 show the test electrode 7 as part of the common electrode.
FIG. 8 shows an example in which the test electrodes are formed in a tapered shape, and FIG. 9 shows an example in which the test electrodes are formed in a stepped shape. In this case as well, by measuring the resistance value between the common electrode 6 and the grinding wheel and terminating the grinding when it reaches a predetermined value, the grinding process can be carried out to a predetermined position.

All of the above embodiments are examples in which a metal layer is used as the test conductor film, but a resistor layer may also be used. FIGS. 10 and 11 show two examples of such cases. As shown in the cross-sectional view at the top of Figure 10, by leaving the resistor layer 4 at the edge of the substrate, which is normally removed by etching, the amount of grinding can be detected from the remaining amount of the resistor layer as the grinding progresses. can do. Therefore, by grinding while measuring the resistance value between the common electrode 6 and the grinding wheel 22, it is possible to grind to a predetermined position.

Furthermore, as shown in FIG. 11, by patterning the resistor layer 4 in the vicinity of the common electrode 6, the amount of grinding can be similarly controlled by the presence or absence of continuity between the common electrode and the grinding wheel and by changes in resistance value. be able to.

(g) Effects of the Invention As described above, according to the present invention, since the amount of grinding is controlled based on the conductor film formed on the substrate,
Accuracy of external dimensions and quality of finished surface can be improved. Furthermore, since machining can be performed while measuring the amount of grinding without the need for optical measurement, it is possible to prevent a deterioration in the yield rate and an increase in working time due to over-shaving or under-shaving.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a method for manufacturing a thermal head according to an embodiment of the present invention, FIGS. 2A to C are diagrams showing an example of grinding, and FIGS. Diagram showing the structure of the head, No. 5
Figures 1 to 11 are diagrams showing the structure of a thermal head according to another embodiment. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Glaze layer, 3... Resistor layer, 4... Resistor layer (conductor film for inspection), 5... Lead electrode, 6... Common electrode, 7... Electrode for inspection, 8...Protective film.

Claims (1)

[Claims] 1. A conductive film for inspection is provided on the substrate of the thermal head between the heat generating part and the edge of the board near the heat generating part, and while grinding the end surface of the board near the heat generating part inward using a conductive grinding tool. . A method for manufacturing a thermal head, comprising: measuring an electrical resistance value between the inspection conductor film and the grinding tool; and terminating the grinding when the resistance value reaches a predetermined value.