JPH09207366A - Thermal head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the execution of the measurement of resistive value without using an exclusive measuring device or the like by a method wherein protective layers are formed excluding the connecting pad parts of separate electrode parts, a heating resistor and the predetermined regions provided between the heating resistor and the connecting pad parts. SOLUTION: Regions (inspecting device contacting regions 36), in which inspecting pad groups 35 are formed, are formed as the predetermined regions provided between a heating resistor 2, on which no protective layer 7 is formed, and connecting pad parts 32. In a thermal head, first of all, on an insulating substrate 1, which is made of ceramic and the surface of which is smoothened, separate electrode patterns 3 each consisting of lead conductor parts 31, connecting pad parts 32 and the inspecting pad parts 35, and connecting patterns 5, which are provided for connecting driving control circuits 4 afterwards mounted on the insulating substrate 1 and the control devices of a recording equipment are formed by printing method. At the same time, the heating resistor 2 is formed by printing method or dispense method.

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 recording device.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing a main structure of an alternating read type thermal head which is an example of this type of thermal head. In FIG. 3, 1 is an insulating substrate made of ceramic or the like, and 2 is an insulating substrate 1. A heat generating resistor formed in the central portion in the longitudinal direction (X direction in the drawing), 3 is an individual electrode portion connected to the heat generating resistor 2, and 4 is formed by dividing the heat generating resistor 2 into the individual electrodes 3. The drive control circuit unit 5 including the drive IC group 41 and the backflow blocking diode array group 42 that selectively heat the heat generating resistance elements to drive the heat generation is a connection pattern unit. The individual electrode portion 3 is connected to the heating resistor 2 and includes a lead conductor portion 31 formed so as to be drawn out near the drive control circuit portion 4 and a connection pad portion 32 provided near the drive control circuit portion 4. The individual electrodes are formed at predetermined intervals in the longitudinal direction of the insulating substrate 1, and are formed on the drive IC group 41 side with the ground side lead conductor group 33,
The power supply side lead conductor groups 34 are formed on the diode array group 42 side, respectively. The connection pattern portion 5 is provided so as to face the individual electrode portion 3 via the drive control circuit portion 4. The drive IC 41 and the backflow prevention diode array 42 are mounted on the insulating substrate 1 such that their respective connection terminals face the connection pad portions 32 of the corresponding ground side lead conductor group 33 and power source side lead conductor group 34. , And each is connected by a bonding wire 6. The control circuit section 4 is connected to the adjacent connection pattern section 5 by a bonding wire 6. The connection pattern section 5 on the side to which the drive IC group 41 is connected is connected to the control section and the ground of the recording device, and the power source is connected to the connection pattern section 5 on the side to which the diode array group 42 is connected.

As a method of driving this thermal head,
A power source is connected to the connection pattern section 5 on the side to which the diode array group 42 is connected, and a drive control signal is input to the connection pattern section 5 on the side to which the drive IC group 41 is connected to control the drive IC 41, and recording is performed. The desired ground-side lead conductor 33 is grounded based on the data. A potential difference is generated between the grounded lead conductor 33 and the adjacent power supply lead conductor 34 which are grounded, and a current flows through the heating resistor element sandwiched between them to generate heat.

As a method of manufacturing this thermal head,
First, an individual electrode pattern 3 and a connection pattern 5 are formed by a printing method on an insulating substrate 1 made of ceramic or the like having a smooth surface, and a heating resistor 2 is formed by a printing method or a dispensing method.

Next, a glass material is overcoated on the heating resistor 2 and the lead conductor portion 31 of the individual electrode pattern 3 to form a protective layer 7. At this time, the protective layer 7 is not formed on the connection pad portion 32 of the individual electrode pattern 3 and is left exposed.

When the heating resistor 2, the individual electrode pattern 3, the connection pattern 5 and the protective layer 7 are formed on the insulating substrate 1, conduction of each heating resistor element, resistance value measurement and resistance value adjustment are performed. That is, in this resistance value measuring step, a measuring jig (probe card) having a plurality of probes arranged corresponding to the connection pad portions 32 of the individual electrode pattern 3 is used, and the plurality of probes are respectively corresponded. The resistance value of each heating resistance element is measured by bringing it into contact with the connection pad portion 32. As a result of this measurement, if there is an element having a resistance value that is apart from the average resistance value of the heating resistor 2 by a predetermined value or more, the resistance value is adjusted. In this resistance value adjusting step, all the heating resistor elements are adjusted by adjusting the firing conditions and firing again, or by electrically changing the resistance value for each element (so-called trimming method). Adjust so that the resistance value of is uniform.

After the resistance value adjusting process is completed, the driving IC 41 and the backflow prevention diode array 4 are provided on the insulating substrate 1.
2 are mounted and connected to the corresponding connection pad portion 32 and connection pattern portion 5 of the individual electrode pattern 3 by the bonding wire 6. Further, a sealing material 8 made of silicon or the like is applied and formed on the connection pattern portion 5 and the connection pad portion 32 which are connected to the drive control circuit portion 4 by the bonding wire 6 to cover these connection portions. This prevents the occurrence of poor contact after connection.

Through the above steps, the substrate portion of the thermal head is completed, and thereafter, the insulating substrate 1 on the aluminum base as the base and the flexible substrate connected to the connection pattern portion 5 of the insulating substrate 1, The thermal head is assembled by attaching a head cover (protective cover) for covering the connection pattern portion 5, the drive control circuit portion 4, and the connection pad portion 32 of the flexible substrate and the insulating substrate 1.

[0009]

In the case of this type of thermal head, the distance from the heating resistor 2 to the drive control circuit section 4, that is, the length of the insulating substrate 1 in the lateral direction (Y direction in the drawing) is It is determined by the size of the platen or the like of the recording apparatus using the thermal head. That is, in the case of a recording apparatus that performs recording by pressing the thermal head against a cylindrical platen roller having a small diameter, the distance between the heating resistor 2 and the drive control circuit 4, that is, the lead, as in the thermal head shown in FIG. Even if the conductor portion 31 is formed to have a relatively short length, when the thermal head is pressed against the platen roller, the distance from the drive control circuit portion 4 becomes sufficiently large, and the protective cover and the platen mounted on the drive control circuit portion 4 are provided. In the case of a recording apparatus using a platen roller having a large diameter, the rollers do not come into contact with each other, but if the distance between the heating resistor 2 and the drive control circuit unit 4 is short, the drive control circuit unit is pressed when the thermal head is pressed against the platen roller. The protective cover mounted on 4 contacts the platen roller, and the heating resistor 2 cannot be pressed against the platen roller. Therefore, in the thermal head of the recording apparatus using the platen roller having a large diameter, the lead conductor portion 31 of the individual electrode pattern 3 is formed to be long as shown in FIG. 4, and the drive IC group 41 and the backflow prevention diode array group 42 are formed. Is configured so that the heating resistor 2 is satisfactorily pressed against the platen roller without the protective cover or the like coming into contact with the platen roller.

As described above, in the case of the conventional thermal head, the pattern of the individual electrode portion 3 (the length of the lead conductor portion 31) to be formed is different according to the specifications of the recording apparatus in which the thermal head is mounted. It is also necessary to separately prepare a probe card for measuring the resistance value of the heating resistor used in the above. Therefore, the cost for the inspection device increases and the manufacturing cost rises. Furthermore, in the resistance value measurement process, the inspection device must be appropriately replaced according to the type of thermal head. Was complicated. Further, in the case of the conventional thermal head, since the inspection device for the connection pad of the individual electrode portion is contacted for inspection and measurement, after the drive control circuit is mounted and connected on the insulating substrate, the drive control is performed. The same measuring jig could not be used for checking the operation of the circuit and checking the connection failure.

The present invention has been made to solve these problems, and an object of the present invention is to provide a thermal head capable of performing resistance value measurement and the like without using a dedicated measuring device, and a method of manufacturing the same. .

[0012]

In order to solve the above-mentioned problems, in the thermal head of the present invention, the heating resistor and the protective layer formed on the individual electrode portion are connected to the connection pad portion of the individual electrode portion and It is configured to be formed except for a predetermined region provided between the heating resistor and the connection pad portion.
Further, in the method for manufacturing a thermal head of the present invention, the heating resistor and the protective layer of the individual electrode portion are provided except for the connection pad portion of the individual electrode portion and a predetermined region provided between the heating resistor and the connection pad portion. By making the inspection device contact the individual electrode portion in a predetermined area provided between the heating resistor and the connection pad portion, the resistance value of each heating resistor element in the heating resistor is measured. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A thermal head and a manufacturing method thereof according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a structure of a thermal head of the present invention, and structures equivalent to or corresponding to the above-described conventional thermal head are indicated by the same symbols. The individual electrode portion 3 in the thermal head of the present invention is connected to the heating resistor 2 and is connected to the lead conductor portion 31 configured to be drawn out in the vicinity of the drive control circuit portion 4 and for connection provided in the vicinity of the drive control circuit portion 4. It is composed of a pad 32 and an inspection pad 35 provided for each lead conductor portion 31 between the connection pad 32 and the heating resistor 2. The inspection pad group 35 is formed in correspondence with the arrangement of the probe pins of the measuring jig used when conducting and measuring the resistance value. Further, the protective layer 7 made of a glass material is formed on the heating resistor 2 and the individual electrode portion 3 except for the region where the inspection pad group 35 is formed. The layer 7 is formed between the inspection pad group 35 formed on the drive IC group 41 side and the inspection pad group 35 formed on the backflow blocking diode array group 42 side. That is, the region where the inspection pad group 35 is formed (inspection device contact region 36) is formed as a predetermined region provided between the heating resistor 2 where the protective layer 7 is not formed and the connection pad portion 32. .

Next, a method of manufacturing the thermal head of the present invention will be described. In the thermal head of the present invention, first,
An individual electrode pattern 3 including a lead conductor portion 31, a connection pad portion 32 and an inspection pad portion 35 on an insulating substrate 1 made of ceramic or the like with a smooth surface, and a drive which is later mounted on the insulating substrate 1. The connection pattern 5 provided for connecting the control circuit 4 and the control device of the recording apparatus is formed by a printing method, and the heating resistor 2 is formed by a printing method or a dispensing method.

Next, the individual electrode portion 3 excluding the inspection device contact region 36 in which the connection pad portion 32 and the inspection pad portion 35 are provided and the heating resistor 2 (that is, two inspection portions formed to face each other). A glass material is overcoated on a region between the pad groups 35, and then the glass material is baked to form the protective layer 7. When the heating resistor 2, the individual electrode pattern 3, the connection pattern 5 and the protective layer 7 are formed on the insulating substrate 1, the conduction test, the resistance value measurement and the resistance value adjustment of each heating resistance element are performed.

In the resistance value measuring step in the thermal head of the present invention, the probe value of the measuring jig is brought into contact with the inspection pad portion 35 to measure the resistance value of each heating resistance element. That is, in the thermal head of the present invention, the inspection pad 35 is provided on the lead conductor portion 31 of each individual electrode portion 3 in accordance with the arrangement of the probe pins of the measuring jig used when measuring the resistance value of each heating resistance element. Since the protective layer 7 is not formed in the portion where the inspection pad 35 is formed, the probe pin of the measuring device can be brought into direct contact with the inspection pad 35, that is, the lead conductor 31. Then, the resistance value of the heating resistance element is measured in this state.
As a result of this measurement, if there is an element having a resistance value which is apart from the average value of the heating resistor 2 by a predetermined value or more, the resistance value is adjusted.

After the resistance value adjustment is completed, the drive IC 41 and the backflow prevention diode array 42 are mounted on the insulating substrate 1, and the connection pads of the individual electrode pattern 3 corresponding to the connection terminals of the drive control circuit 4 respectively. 32 and the connection pattern 5 are connected by a bonding wire 6.

In the thermal head of the present invention, after the drive control circuit 4 is mounted and connected on the insulating substrate 1, the operation of each drive IC can be confirmed. That is, after connecting the drive control circuit 4 and the connection pad portion 32 of the individual electrode pattern 3 by the bonding wire 6, the probe pin of the measuring device used in the above-mentioned resistance value measuring step is brought into contact with the inspection pad portion 35, The drive control circuit 4 is operated in this state. From the detection result of the measuring device at this time, a defect of the drive control circuit 4 or a connection defect of the bonding wire 6 is detected.

After confirming the operation of the drive control circuit 4, the connection pattern portion 5 and the connection pad portion 32 connected to the drive control circuit portion 4 by the bonding wire 6,
The region where the inspection pad portion 35 is formed, that is, the portion not overcoated with the protective layer 7 is sealed with the sealing material 8.

Since the portion connected by the drive control circuit 4 and the bonding wire 6 largely projects on the insulating substrate 1, the first sealing material 81 made of silicon or the like is formed into a semi-cylindrical shape at this portion. The drive control circuit 4, the bonding wire 6 and the connecting portion (a part of the connecting pad portion 32 and the connecting pattern portion 5) are formed and sealed. In addition, the inspection device contact region 36 in which the inspection pad portion 35 is formed has a second sealing material 82 made of a sealing tape made of an insulating material or silicon or the like formed in a flat shape.
Sealed.

The substrate portion of the thermal head is completed by the above steps, and thereafter, like the conventional thermal head described above, the insulating substrate 1, the flexible substrate, the head cover, etc. are attached to the aluminum base to assemble the thermal head. I do.

In the above-described embodiment, the connection pad portion 35 is formed in the region 36 to be contacted with the inspection device, but the resolution is relatively low and the lead conductor 3 of the individual electrode portion is formed.
When 1 can be formed with a width wide enough to contact the inspection device, it is not necessary to particularly provide the connection pad portion 35. FIG. 2 is a diagram showing a second embodiment of the present invention. The difference from the first embodiment described above is that the inspection device is brought into contact with the lead conductor portion 31 without providing the connection pad portion 35. That is the point. That is, in the thermal head of the second embodiment, the inspection device contact region 36 where the protective layer 7 is not formed is provided at the portion where the contact probe of the inspection device used when measuring the resistance value contacts, and the resistance value at the manufacturing stage is set. In the measurement step and the operation confirmation step of the drive control circuit, the probe of the inspection device comes into contact with the lead conductor portion 31 in the inspection device contact region 36, so that conduction,
The resistance value of the heating resistance element is measured, the resistance value is adjusted, and the operation of the drive control circuit is checked.

After various inspection and adjustment processes have been carried out, the inspection device contact region 36 in which the protective layer 7 is not formed is made of an insulating material like the region in which the inspection pad group 35 in the first embodiment is formed. It is sealed with a sealing tape or a sealing material 82 made of silicon or the like formed in a flat shape.

As described above, in the thermal head of the present invention, the inspection device contact region 36 in which the protective layer 7 is not formed is provided on the individual electrode portion 3 in correspondence with the jig of the measuring device used when measuring the resistance value. Therefore, it is not necessary to prepare an inspection device according to the type of the thermal head, and it is possible to inspect and measure thermal heads of various sizes with one type of measuring jig. Moreover, since the inspection device can be brought into contact with the individual electrode portion even after the drive control circuit is mounted on the insulating substrate and connected, the operation check of the drive control circuit and the connection failure inspection should be performed using the same measuring jig. You can

In the above-described embodiment, the alternate lead type thermal head is shown in which the driving IC is connected to one individual electrode and the backflow prevention diode array is connected to the other individual electrode with the heating resistor interposed therebetween. However, the present invention is not limited to this, and it is needless to say that it may be applied to a thermal head having drive ICs connected on both sides and can be applied to various types of thermal heads.

[0026]

As described above in detail, in the thermal head of the present invention, the protective layer formed on the heating resistor and the individual electrode portion is connected to the connection pad portion of the individual electrode portion and the heating resistor. It is configured to be formed except for a predetermined area provided between the pad portions, and as a manufacturing method thereof, a protective layer for the heating resistor and the individual electrode portion is connected to the pad portion for connecting the individual electrode portion and the heating resistor. It is formed by excluding the predetermined area provided between the pad portions, and the inspection device is brought into contact with the individual electrode portion in the predetermined area provided between the heating resistor and the connection pad portion, so that each heat generation of the heating resistor is performed. Since the resistance value of the resistance element is measured, it is possible to inspect using one type of measuring jig without using a dedicated measuring device for thermal heads of various sizes.
It is possible to perform measurement and the like, and even after the drive control circuit is mounted on the insulating substrate and connected, the operation check of the drive control circuit and the connection failure inspection can be performed using the same measuring jig. Play.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a thermal head of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a conventional thermal head.

FIG. 4 is a diagram showing a configuration of a conventional thermal head.

[Explanation of symbols]

 1 Insulating Substrate 2 Heating Resistor 3 Individual Electrode Section 4 Drive Control Circuit Section 5 Connection Pattern Section 6 Bonding Wire 7 Protective Layer 8 Sealing Material

Claims (2)

[Claims] 1. A heating resistor which is linearly formed on an insulating substrate, and an individual electrode portion including a plurality of lead conductors, one end of which is connected to the heating resistor and the other end of which is provided with a connection pad. In the thermal head having a protective layer formed on the heating resistor and the individual electrode section, the protective layer is provided between the connecting pad section of the individual electrode section and the heating resistor and the connecting pad section. A thermal head characterized by being formed excluding a predetermined region. 2. A step of forming, on an insulating substrate, a heating resistor and a plurality of individual electrode portions formed of a plurality of lead conductors, one end of which is connected to the heating resistor and the other end of which is provided with a connecting pad, A step of forming a protective layer on the heating resistors and the individual electrode portions, and then firing the layers, except for a predetermined area provided between the connection pad portion of the electrode portion and the heating resistor and the connection pad portion; A thermal head having a step of measuring the resistance value of the heating resistor by bringing an inspection device into contact with an individual electrode portion in a predetermined region provided between the heating resistor not having a layer formed thereon and the connection pad. Manufacturing method.