JPH10272797A - Thermal head - Google Patents

Thermal head

Info

Publication number
JPH10272797A
JPH10272797A JP7867097A JP7867097A JPH10272797A JP H10272797 A JPH10272797 A JP H10272797A JP 7867097 A JP7867097 A JP 7867097A JP 7867097 A JP7867097 A JP 7867097A JP H10272797 A JPH10272797 A JP H10272797A
Authority
JP
Japan
Prior art keywords
driver
insulating substrate
hole
thermal head
recording medium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP7867097A
Other languages
Japanese (ja)
Other versions
JP3477022B2 (en
Inventor
Toshiaki Michihiro
利昭 道廣
Original Assignee
Kyocera Corp
京セラ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kyocera Corp, 京セラ株式会社 filed Critical Kyocera Corp
Priority to JP7867097A priority Critical patent/JP3477022B2/en
Publication of JPH10272797A publication Critical patent/JPH10272797A/en
Application granted granted Critical
Publication of JP3477022B2 publication Critical patent/JP3477022B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Abstract

(57) [Summary] When a driver IC is buried in a hole of an insulating substrate, a terminal electrode and an electric circuit on the upper surface of the IC are damaged by pressing of dust. A hole (1a) is provided in an insulating substrate (1) having a heating resistor (3) and conductive layers (4b, 4c), and a driver IC (5) having a terminal electrode (5a) on its upper surface is buried in the hole (1a) and a terminal electrode of the driver IC (5) is provided. A thermal head formed by electrically connecting the conductive layers (4b, 4c) to each other by extending the conductive layers (5a, 5b) on the insulating substrate (1), wherein a hard resin having a Shore hardness of 120 or more is provided between a hole wall surface of the insulating substrate (1) and a driver IC side surface. 6 and the upper surface of the driver IC is covered with a soft resin 7 having a Shore hardness of 95 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a thermal head incorporated as a printer mechanism of a word processor, a facsimile or the like.

[0002]

2. Description of the Related Art In recent years, attempts have been made to make the surface of a thermal head in contact with a recording medium as flat as possible in order to perform thermal recording on a hard recording medium such as a plastic card which is difficult to bend.

In such a conventional thermal head, for example, as shown in FIG. 3, a hole 11a is provided in an insulating substrate 11 having a heating resistor 13 and a conductive layer 14, and a heating resistor is provided in the hole 11a. 13 has a structure in which a driver IC 15 for controlling heat generation is embedded.
5 is buried in the hole portion 11a of the insulating substrate 11, so that there is no longer a protruding portion on the surface of the thermal head, so that printing is performed on a hard recording medium P such as a plastic card which is difficult to bend. Even in the case of performing this, a flat path in which the recording medium P is conveyed onto the heating resistor 13 in a substantially flat shape becomes possible. In the above-described thermal head, a resin material 16 for fixing the driver IC 15 is filled between the hole wall surface of the insulating substrate 11 and the side surface of the driver IC. The heating resistor 13 and the like are electrically connected to the driver IC 15 via the conductive layer 14 by extending the layer 14 to above the terminal electrode 15a on the upper surface of the driver IC.

When printing is performed by using the above-described thermal head, for example, the ink ribbon and the recording medium P are conveyed to the heating resistor 13 via the driver IC 15 while the driver IC 15 is being driven. And heat is applied to the heating resistor 13 to selectively cause the heating resistor 13 to individually generate Joule heat, and the generated heat heats and melts the ink of the ink ribbon, and this is heated using an external platen or the like. An image is formed on the recording medium P by pressing and transferring to the recording medium P side.

[0005]

However, according to such a conventional thermal head, the upper surface of the driver IC 15 embedded in the hole 11a of the insulating substrate 11 has
An electric circuit such as a terminal electrode 15a and a switching transistor is provided. Therefore, when a hard recording medium P such as a plastic card is conveyed along the surface of the thermal head at the time of printing, the recording medium P or the like is moved between the upper surface of the driver IC 15 and the hard recording medium P by the action of static electricity or the like. The attached large dust is bitten, and the pressing of the dust has a disadvantage that the electric circuit such as the terminal electrode 15a of the driver IC 15 and the switching transistor is damaged.

In the above-mentioned conventional thermal head, a resin material 16 for fixing the driver IC 15 is used.
Is formed of a soft resin such as a silicone resin, when large dust adhering to the ink ribbon or the recording medium P is caught between the upper surface of the driver IC 15 and the recording medium P, the resin material 16 generates dust. The conductive layer 14 deposited on the resin material 16 may be severely deformed by the pressing, and may be disconnected.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has a driver provided with a hole in an insulating substrate having a heating resistor and a conductive layer, and having a terminal electrode on the upper surface in the hole. A thermal head in which an IC is embedded and the conductive layer is extended and electrically connected to terminal electrodes of a driver IC, wherein a Shore hardness is defined between a hole wall surface of the insulating substrate and a side surface of the driver IC. A hard resin having a hardness of 120 or more is filled, and the upper surface of the driver IC is covered with a soft resin having a Shore hardness of 95 or less.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view showing an embodiment of the thermal head of the present invention, and FIG. 2 is a cross-sectional view taken along the line XX of FIG. 1, wherein 1 is an insulating substrate, 1 a is a hole, 3 is a heating resistor,
4c is a conductive layer, 5 is a driver IC, 6 is a hard resin,
7 is a soft resin.

The insulating substrate 1 has a thickness of 0.5 to 1.5 mm.
And a plurality of holes 1a are provided on the upper surface thereof.

The insulating substrate 1 supports a heating resistor 3 and conductive layers 4a to 4c to be described later on its upper surface, and a driver IC 5 to be described later is embedded in the hole 1a so that the upper surface of the driver IC 5 is a thermal head. An effect is provided to prevent the recording medium P from protruding more than the upper surface, thereby enabling a flat pass of the recording medium P.

When the insulating substrate 1 is formed of, for example, alumina ceramics, an organic solvent suitable for a ceramic raw material powder such as alumina, silica, magnesia, etc.
A solvent is added and mixed to form a slurry, and a ceramic green sheet is formed by adopting a conventionally known doctor blade method, calender roll method, or the like.
Thereafter, the ceramic green sheet is manufactured by punching the ceramic green sheet into a predetermined shape and firing at a high temperature. Thereafter, the upper surface of the obtained insulating substrate 1 is irradiated with a laser having a predetermined intensity, and a part thereof is melted and scattered. Or a part of the insulating substrate 1 is cut to form the hole 1a.

On the upper surface of such an insulating substrate 1,
Partial glaze layer 2 having a mountain-like cross section and a plurality of heating resistors 3
And conductive layers 4a to 4c of a predetermined pattern are respectively applied.

The partial glaze layer 2 is made of a material having a low thermal conductivity such as glass. A plurality of heating resistors 3 attached near the top of the glaze layer 2 are projected upward to press the recording medium P or the like. And effectively accumulates the heat generated by the heat generating resistor 3 to an appropriate temperature to maintain the thermal response characteristic of the thermal head satisfactorily.

The heating resistor 3 is formed of the partial glaze layer 2.
Are arranged and arranged near the top of each of them, and each of them is formed of an electric resistance material such as tantalum nitride, so that when external power is applied through conductive layers 4a and 4b described later, Joule heat is generated. When printing is performed using, for example, an ink ribbon, the ink has a function of generating heat to a predetermined temperature required for melting the ink, for example, a temperature of 150 to 250 ° C.

The conductive layers 4a to 4c are connected to one end of the heating resistor 3 and serve as a common electrode.
A conductive layer 4b as an individual electrode connecting the other end of the heating resistor 3 to the terminal electrode 5a of the driver IC 5, and a conductive layer 4c as a control signal line for supplying a print signal or the like to the driver IC 5, The conductive layers 4a and 4b function to apply external power to the heating resistor 3, and the conductive layer 4c controls an external printing signal and the like for a driver IC.
5 is supplied.

The partial glaze layer 2 is formed by printing and applying a glass paste obtained by adding and mixing an appropriate organic solvent and an organic solvent to a predetermined glass powder by a conventionally known screen printing or the like. About 1000 ° C. to 1200
The heating resistor 3 and the conductive layer 4 are attached and formed in a band shape on the upper surface of the insulating substrate 1 by baking at a temperature of
a to 4c are deposited and arranged in a predetermined thickness and a predetermined pattern by employing a conventionally known thin film forming technique such as a sputtering method and a photolithography technique.

A plurality of driver ICs 5 are individually embedded in the plurality of holes 1a provided in the insulating substrate 1.

The driver IC 5 has a plurality of terminal electrodes 5a on its upper surface which are electrically connected to the conductive layers 4b and 4c.
And an electric circuit such as a switching transistor are formed, respectively. When an external printing signal or the like is supplied through the conductive layer 4c or the like, the conductive layers 4a, 4a,
4b of the power applied to the heating resistor 3 via the
Off is controlled.

A shore hardness of 120 is provided between the hole wall surface of the insulating substrate 1 and the side surface of the driver IC 5.
The above hard resin 6 is filled, and the driver IC
5 is covered with a soft resin 7 having a Shore hardness of 95 or less.

The hard resin 6 is prepared, for example, by mixing an epoxy resin, a polyimide resin and a polyetheramide at a predetermined ratio, and adding an alumina filler having an average particle size of about 25 μm at a content of 50 to 80% by weight. The driver IC 5 is firmly fixed at a predetermined position in the hole 1a, and the upper surface of the hard resin 6 is
Positioning at approximately the same height as the upper surface of C5 has the effect of facilitating the formation of conductive layers 4b and 4c deposited thereon as a good continuous film.

On the other hand, the soft resin 7 is made of an epoxy resin or a polyimide resin containing no alumina filler or the like, and is adjusted to a Shore hardness of 95 or less. When transported along the surface of the thermal head,
Between the upper surface of the driver IC 5 and the hard recording medium P,
Even if large dust adhering to the recording medium P or the like is caught by the action of static electricity or the like, the soft resin 7 itself absorbs the external force due to the pressing of the dust by being elastically deformed or shaved. The terminal electrode 5a on the upper surface of the driver IC and the electric circuit can be effectively prevented from being damaged, and the reliability of the thermal head can be improved.

Further, since the Shore hardness of the hard resin 6 filled between the hole wall surface of the insulating substrate 1 and the side surface of the driver IC is adjusted to 120 or more, when the soft resin 7 is deformed as described above, Even so, the hard resin 6 is hardly deformed, and the conductive layers 4b and 4c interposed therebetween can be maintained in a good state. Therefore, the conductive layer 4
The disconnection of b and 4c is effectively prevented, which also improves the reliability of the thermal head.

When the hard resin 6 has a Shore hardness of less than 120, large dust is caught between the upper surface of the driver IC 5 and the recording medium P, and the soft resin 7 is elastically deformed. The conductive layer 4 between the hard resin 6 and the soft resin 7 also deforms the hard resin 6 thereunder.
b, 4c may be disconnected, and the soft resin 7
If the Shore hardness is greater than 95, when large dust is caught between the upper surface of the driver IC 5 and the recording medium P, the soft resin 7 hardly undergoes elastic deformation, and the surface of the recording medium P is damaged. There is a risk that it will. Therefore, the Shore hardness of the hard resin 6 needs to be set to 120 or more, and the Shore hardness of the soft resin 7 needs to be set to 95 or less.

The hard resin 6 has an average particle size of 25 μm.
A varnish such as an epoxy resin containing about 80% by weight of an alumina filler in an insulating substrate 1 using a dispenser or the like.
Between the hole wall surface and the side surface of the driver IC 5, which is filled by thermosetting at a temperature of about 150 ° C. The soft resin 7 is a varnish such as an epoxy resin containing no alumina filler or the like. Is formed by applying a known method such as screen printing so as to cover the holes 1a of the insulating substrate 1, and thermally curing the same at a temperature of about 150 ° C. At this time, the distance between the hole wall surface of the insulating substrate 1 and the side surface of the driver IC 5 is 200 to 6
If it is kept at 00 μm, bubbles are hardly generated between the hole wall surface and the IC side surface when the hard resin 6 is filled,
Further, the occurrence of misalignment due to shrinkage during the condensation polymerization is reduced. Therefore, the distance between the hole wall surface of the insulating substrate 1 and the side surface of the driver IC 5 is preferably maintained at 200 to 600 μm.

Thus, in the above-described thermal head of the present invention, for example, the ink ribbon and the recording medium P are conveyed along the surface of the thermal head (onto the heating resistor 3 via the driver IC 5), while the ink ribbon and the recording medium P are conveyed. With the driving, power is applied to the heating resistors 3 via the conductive layers 4a and 4b, and the heating resistors 3 are individually and selectively joule-heated, and the generated heat heats and melts the ink of the ink ribbon. This is pressed and transferred to the recording medium P using an external platen or the like to form an image on the recording medium P, thereby functioning as a thermal head.

It should be noted that the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the scope of the present invention.
If the surface roughness is set in the range of 2,000 to 40,000 mm in center line average roughness Ra, the dust is efficiently captured by the unevenness of the surface. It will be effectively prevented.

In the above embodiment, a part of the heating resistor 3 and the conductive layers 4a to 4c may be covered with a wear-resistant layer formed of silicon nitride or the like. By doing so, it is possible to prevent the heating resistor 3 and the like from being worn by sliding contact of the recording medium P and the like, and to prevent the heating resistor 3 and the like from being corroded by contact with moisture contained in the atmosphere.

[0028]

According to the thermal head of the present invention, the space between the hole wall surface of the insulating substrate and the side surface of the driver IC is filled with a hard resin having a Shore hardness of 120 or more, and the upper surface of the driver IC is made of a soft resin having a Shore hardness of 95 or less. Due to the resin coating, when a hard recording medium such as a plastic card is conveyed along the surface of the thermal head at the time of printing, recording is performed between the upper surface of the driver IC and the hard recording medium by the action of static electricity or the like. Even if large dust adhering to a medium or the like is bitten, the soft resin itself absorbs the external force due to the pressing of the dust by being elastically deformed or scraped. The circuit can be effectively prevented from being damaged, and the reliability of the thermal head can be improved.

Further, according to the thermal head of the present invention, since the Shore hardness of the hard resin filled between the hole wall surface of the insulating substrate and the side surface of the driver IC is 120 or more, the soft resin is deformed as described above. Even in this case, the hard resin is hardly deformed, and the conductive layer interposed between the two can be maintained in a good state. Therefore, disconnection of the conductive layer can be effectively prevented, thereby also improving the reliability of the thermal head.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a thermal head according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view of a conventional thermal head.

[Explanation of symbols]

 1 ... Insulating substrate 1a ... Hole 3 ... Heating resistor 4b, 4c ... Conductive layer 5 ...・ ・ ・ ・ ・ ・ Driver IC 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ Hard resin 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ Soft resin

Claims (1)

    [Claims]
  1. A hole is formed in an insulating substrate having a heating resistor and a conductive layer, a driver IC having a terminal electrode on the upper surface is buried in the hole, and the conductive layer extends on the terminal electrode of the driver IC. A thermal head which is electrically connected to the space between the hole surface of the insulating substrate and the side surface of the driver IC with a hard resin having a Shore hardness of 120 or more and the upper surface of the driver IC has a Shore hardness of 95 or less. A thermal head characterized by being coated with a soft resin.
JP7867097A 1997-03-31 1997-03-31 Thermal head Expired - Fee Related JP3477022B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7867097A JP3477022B2 (en) 1997-03-31 1997-03-31 Thermal head

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7867097A JP3477022B2 (en) 1997-03-31 1997-03-31 Thermal head

Publications (2)

Publication Number Publication Date
JPH10272797A true JPH10272797A (en) 1998-10-13
JP3477022B2 JP3477022B2 (en) 2003-12-10

Family

ID=13668313

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7867097A Expired - Fee Related JP3477022B2 (en) 1997-03-31 1997-03-31 Thermal head

Country Status (1)

Country Link
JP (1) JP3477022B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018181734A1 (en) * 2017-03-29 2018-10-04 京セラ株式会社 Thermal head and thermal printer

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018181734A1 (en) * 2017-03-29 2018-10-04 京セラ株式会社 Thermal head and thermal printer
JP6419405B1 (en) * 2017-03-29 2018-11-07 京セラ株式会社 Thermal head and thermal printer
CN110461614A (en) * 2017-03-29 2019-11-15 京瓷株式会社 Thermal head and thermal printer

Also Published As

Publication number Publication date
JP3477022B2 (en) 2003-12-10

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