JP2003220725A - Thermal head - Google Patents

Thermal head

Info

Publication number
JP2003220725A
JP2003220725A JP2002022526A JP2002022526A JP2003220725A JP 2003220725 A JP2003220725 A JP 2003220725A JP 2002022526 A JP2002022526 A JP 2002022526A JP 2002022526 A JP2002022526 A JP 2002022526A JP 2003220725 A JP2003220725 A JP 2003220725A
Authority
JP
Japan
Prior art keywords
sealing
thermal head
driver
base plate
driver ics
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.)
Pending
Application number
JP2002022526A
Other languages
Japanese (ja)
Inventor
Iwao Kobayashi
Masakazu Norita
Yuko Ushiyama
巌 小林
昌和 法田
祐幸 牛山
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 JP2002022526A priority Critical patent/JP2003220725A/en
Publication of JP2003220725A publication Critical patent/JP2003220725A/en
Pending legal-status Critical Current

Links

Abstract

(57) [Summary] [PROBLEMS] To effectively prevent longitudinal warpage, to form a good print with almost no density unevenness or blur, and to maintain high productivity and reliability. Provide high quality thermal head. A plurality of driver ICs are linearly arranged and mounted on a main surface of a base plate provided with a heating element array, with a predetermined interval therebetween, and the driver ICs are arranged in the linear arrangement. In a thermal head which is covered in common with a single sealing material 7 continuously formed in the direction, the width of the sealing material 7 is set to be smaller than the mounting area of the driver IC 6 by 6-6 Make the area narrower.

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 as a recording device such as a facsimile or a video printer.

[0002]

2. Description of the Related Art Conventionally, thermal heads have been widely used as recording devices for facsimiles and the like.

As such a conventional thermal head, for example, as shown in FIG. 4, a heating element array 13A composed of a large number of heating elements 13 linearly arranged on the upper surface of a base plate 11 made of alumina ceramics, etc., and these heating elements. A plurality of driver ICs 16 for controlling the heat generation of 13
Driver and the driver IC1
There is known a structure in which 6 is commonly covered with a single encapsulant 17 having an epoxy resin as a main component, and a large number of heating elements are fed while feeding a recording medium such as thermal paper onto the heating element array 13A. A predetermined print is formed by causing 13 to selectively generate Joule heat on the basis of image data from the outside and to transfer these heats to the recording medium.

Incidentally, the sealing material 17 is a driver IC1.
By blocking 6 from the atmosphere, the electronic circuit of the driver IC 16 is prevented from being corroded by moisture in the atmosphere, and is generally formed in a substantially constant width in the arrangement direction of the driver IC 16. It was target.

In addition, such a sealing material 17 is formed by applying a liquid epoxy resin precursor to a predetermined region (mounting region of the driver IC 16) on the upper surface of the base plate in a strip shape by a conventionally known dispenser method or the like. Was formed by heating and polymerizing at high temperature.

[0006]

However, in the above-mentioned conventional thermal head, the base plate 1
The linear expansion coefficient of the alumina ceramics or the like forming 1 and the epoxy resin forming the sealing material 17 is greatly different, and the sealing material 17 is bonded to the base plate 11 in a relatively wide area. Therefore, when the precursor of the epoxy resin is heated at a high temperature when the sealing material 17 is formed and then cooled to room temperature, a large warp in the longitudinal direction of the thermal head due to the thermal stress between the sealing material 17 and the base plate 11 occurs. May occur. In that case, the linearity of the heating element array 13A is remarkably lost, and it becomes difficult to press all the heating elements 13 against the recording medium with a uniform strength, which causes printing defects such as density unevenness and scraping. Had.

Therefore, in order to solve the above-mentioned drawbacks, the sealing material 17 is separated for each driver IC and the driver IC 16 is separated.
It is conceivable to reduce the adhesion area (total area) of the sealing material 17 to the base plate 11 by individually coating the sealing material 17 with the sealing material 17.

However, a plurality of driver ICs 1
When 6 is individually covered with a plurality of sealing materials 17, it takes a long time to apply the liquid precursor when forming the sealing materials 17, and the productivity of the thermal head is significantly reduced. A large bulge due to the surface tension of the liquid precursor is formed near both ends of each sealing material 17, and these bulges exist between the adjacent driver ICs.
If the running recording medium comes into contact with these bulges, the running of the recording medium becomes extremely unstable, causing a defect such as a paper jam.

The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to effectively prevent warpage in the longitudinal direction and to form a good print having almost no density unevenness and blurring. It is to provide a high quality thermal head capable of maintaining high productivity and reliability.

[0010]

In the thermal head of the present invention, a plurality of driver ICs are linearly arranged and mounted on a main surface of a base plate on which a heating element array is provided, with a predetermined gap therebetween. A thermal head in which these driver ICs are commonly covered with a single sealing material continuously formed in the array direction, wherein the sealing material is larger than the mounting area of the driver IC. It is characterized in that the width between the driver ICs is narrowed.

In the thermal head of the present invention, the width of the sealing material located in the mounting area of the driver IC is 30% to 80% of the width of the sealing material located in the area between the driver ICs.
It is characterized by being set to.

Further, the thermal head of the present invention is characterized in that an insulating layer having a groove corresponding to the pattern of the sealing material is adhered on the upper surface of the base plate.

According to the thermal head of the present invention, the sealing material for commonly covering the plurality of driver ICs mounted on the base plate is narrower in the area between the driver ICs than in the mounting area of the driver ICs. From what I did,
The adhesive area of the sealing material to the base plate can be made as small as possible, and the thermal stress between the base plate and the sealing material can be suppressed to a small level. This effectively prevents the thermal head from warping in the longitudinal direction and maintains a high linearity of the heating element array, so that a good print can be formed.

Further, according to the thermal head of the present invention, the encapsulating material is continuously formed in the driver IC array direction without interruption, so that the liquid precursor is applied in forming the encapsulating material. Work in a relatively short time,
In addition to being able to maintain high productivity of the thermal head, large bulges due to the surface tension of the liquid precursor are formed on the surface of the encapsulant only at both ends in the longitudinal direction.
Such a bulge is not formed between the adjacent driver ICs. Therefore, even if the running recording medium comes into contact with the sealing material, the running of the recording medium does not become extremely unstable, and the recording medium can always be stably run.

Further, according to the thermal head of the present invention, if an insulating layer having grooves corresponding to the pattern of the sealing material is adhered to the upper surface of the base plate prior to the formation of the sealing material, the sealing can be achieved. When forming the stopper, the liquid precursor is effectively prevented from flowing into the groove formed by the insulating layer and attempting to spread to the outside of the groove, so that the liquid precursor has a pattern corresponding to the groove shape. Thus, the width of the sealing material can be controlled in each region with high accuracy.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below in detail with reference to the accompanying drawings. 1 is a plan view of a thermal head according to an embodiment of the present invention, FIG. 2 is a vertical sectional view of the thermal head of FIG. 1, FIG. 3 is a transverse sectional view of the thermal head of FIG. Is a heating element, 6 is a driver IC, 7 is a sealing material, and 8 is an insulating layer.

The base plate 1 is formed of an electrically insulating material such as alumina ceramics so as to have a rectangular shape. The glaze layer 2, the heating element 3, the driver IC 6 and the like are attached to the upper surface of the base plate 1. Functions as a supporting base material for supporting.

When the base plate 1 is made of, for example, alumina ceramics, it is formed into a slurry by adding and mixing an appropriate organic solvent / solvent to ceramics raw material powder such as alumina, silica, magnesia, etc. A ceramic green sheet is formed by employing a blade method or the like, and then the obtained green sheet is punched into a predetermined shape and then fired at a high temperature.

On the upper surface of the base plate 1, a glass glaze layer 2 is applied in a strip shape in the longitudinal direction of the base plate 1, and a large number of heat generating elements 3 are provided near the top.

The glaze layer 2 has a radius of curvature of 1 m, for example.
Base plate 1 so as to form an arcuate section of m to 4 mm
Is partially formed on the upper surface of the, and the thickness thereof is set to, for example, 20 μm to 160 μm just below the top.

Since the glaze layer 2 is made of glass having low thermal conductivity (heat conductivity: 0.7 W / mK to 1.0 W / mK), the heat generating element 3 emits light therein. Function of accumulating a part of heat to maintain good thermal response characteristics of the thermal head, specifically, function as a heat storage layer for raising the temperature of the heating element 3 to a predetermined temperature necessary for printing in a short time. To do.

The partial glaze layer 2 is formed by printing and applying a predetermined glass paste obtained by adding and mixing an appropriate organic solvent to glass powder on the upper surface of the base plate 1 by a conventionally known screen printing method. , Is formed by baking it at a high temperature.

Further, a large number of heating elements 3 provided near the top of the glaze layer 2 are, for example, 600 dpi (dot pe).
The heater elements are arranged linearly in the main scanning direction at a density of r inch), and all of these heater elements 3 form a heater element row 3A.

Each of the heating elements 3 has TaN or T
Since it is formed of an electric resistance material such as aSiO, TiSiO, etc., when power supply power is applied through the circuit pattern 4 electrically connected to both ends thereof, Joule heat is generated and a print is formed on the recording medium. The temperature required for this is, for example, a temperature of 130 to 350 ° C.

The circuit pattern 4 connected to the heating element 3 functions as a power supply wiring for supplying electric power to the heating element 3 and the like, is made of a metal material such as aluminum or copper, and is formed on the glaze layer 2 from above. The base plate 1 is attached and led out over the surface of the base plate 1, and is electrically connected to corresponding terminal electrodes of the driver IC 6 described later at the lead-out portion.

Such a circuit pattern 4 and the above-mentioned heating element 3 are formed on the base plate 1 on which the glaze layer 2 is coated with a conventionally known thin film forming technique, for example, an electric resistance material such as TaN and a metal material such as aluminum. It is formed by sequentially depositing on the upper surface by conventionally well-known sputtering or the like, and processing these sputtered films into a predetermined pattern by conventionally well-known photolithography technique or etching technique.

A protective film 5 is deposited on the surfaces of the above-mentioned many heat generating elements 3 and circuit patterns 4, and the many heat generating elements 3 and circuit patterns 4 are commonly covered by such a protective film 5. .

The protective film 5 is made of an inorganic material having excellent wear resistance such as silicon nitride (Si 3 N 4 ) or sialon (Si-Al-O-N). It has the function of protecting the recording medium from abrasion caused by sliding contact and corrosion caused by contact with moisture contained in the atmosphere.

For such a protective film 5, a conventionally known thin film forming technique, for example, sputtering is adopted, and the above-mentioned inorganic material is formed on the upper surface of the heating element 3, the circuit pattern 4, etc.
It is formed by depositing to a thickness of 20 μm.

On the other hand, on the upper surface of the base plate 1 described above, a plurality of driver ICs 6 are arranged substantially in parallel with the above-mentioned heating element row 3A with a predetermined space therebetween.
It is implemented.

The driver IC 6 has electronic circuits such as a shift register, a latch, and a switching transistor, which are densely integrated on each circuit forming surface, and has a function of selectively heating a large number of heating elements 3. Specifically, the switching transistor is turned on / off based on image data supplied from the outside to control the energization of each heating element 3.

The driver IC 6 is a flip-chip type I having the above-mentioned electronic circuit and terminal electrodes on the lower surface.
C is preferably used, and in that case, conventionally known face-down bonding, that is, the driver IC 6 is mounted at a predetermined position on the base plate 1 by soldering the terminal electrode of the driver IC 6 to the lead-out portion of the corresponding circuit pattern 4. To be done.

Then, the plurality of driver ICs 6 described above
Are commonly covered with a single encapsulant 7 mainly composed of epoxy resin.

The sealing material 7 is, for example, an epoxy resin containing an inorganic filler made of silica (SiO 2 ) or alumina (Al 2 O 3 ) in an amount of about 50 wt% to 70 wt%. This effectively prevents the electronic circuit of the driver IC 6 from being corroded by contact with moisture in the atmosphere, and protects the driver IC 6 from the application of external force (contact with the recording medium, etc.). .

The sealing material 7 is narrower in the area between the driver ICs adjacent to the mounting area of the driver IC 6, specifically, in the area where the sealing material 7 is between the driver ICs. The width is smaller than the width of the IC 6, and the bonding area (total area) of the sealing material 7 to the base plate 1 is smaller than that in the case where the sealing material 7 is formed with a constant width in the arrangement direction of the driver ICs 6.

For example, the width of the sealing material 7 is set to 2 mm to 4 mm in the mounting area of the driver IC 6, and, for example, in the case of 3 mm, in the area between the adjacent driver ICs,
0.9 mm to 2. 30% to 80% of the mounting area
It is set to 4 mm.

In this way, the adhesion area of the sealing material 7 to the base plate 1 is made as small as possible, and the base plate 1-
By suppressing the thermal stress between the encapsulating materials 7 to be small, it becomes possible to effectively prevent the warp of the thermal head in the longitudinal direction, and to maintain a high linearity of the heating element array 3A to obtain a good print. Can be formed.

Further, since the encapsulating material 7 is continuously formed in the arrangement direction of the driver ICs 6 without interruption in the middle, the application of the liquid precursor in forming the encapsulating material 7 can be performed in a relatively short time. By doing so, the productivity of the thermal head can be maintained high, and large bulges due to the surface tension of the liquid precursor are formed on the surface of the encapsulating material 7 only at both ends in the longitudinal direction. Such a bulge is not formed between the adjacent driver ICs. Therefore, even if the running recording medium comes into contact with the sealing material 7, the running of the recording medium does not become extremely unstable, and the recording medium can always be run stably.

The encapsulating material 7 is formed by applying a liquid precursor of an epoxy resin containing, for example, a predetermined amount of an inorganic filler added and mixed to the mounting area of the driver IC 6 in a strip shape by a conventionally known dispenser method. 80 ℃ ~ 20
It is formed by heating and polymerizing at a temperature of 0 ° C.

At this time, prior to the formation of the sealing material 7, an insulating layer (thickness: 10 μm to 50 μm) 8 made of epoxy resin having a groove corresponding to the pattern of the sealing material 7 is formed on the upper surface of the base plate 1. If the liquid precursor is applied, the liquid precursor is effectively prevented from flowing into the groove formed by the insulating layer 8 and attempting to spread to the outside of the groove when the sealing material 7 is formed. Since the precursor is accurately applied to the pattern corresponding to the groove shape, the width of the sealing material 7 can be controlled with high accuracy in each region. Therefore, it is preferable to deposit the insulating layer 8 having the grooves corresponding to the pattern of the sealing material 7 on the upper surface of the base plate 1.

Thus, the above-described thermal head of the present embodiment, while feeding the recording medium onto the heating element array 3A, causes the plurality of heating elements 3 to individually and selectively generate Joule heat as the driver IC 5 is driven. Of the heat is transmitted to the recording medium to form a predetermined image on the recording medium, thereby functioning as a thermal head.

The present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

For example, in the above-described embodiment, the glaze layer 2 is partially formed on the upper surface of the base plate 1, but instead of this, the glaze layer 2 is formed over the entire upper surface of the base plate 1. I don't mind.

In the above embodiment, the base plate 1 is made of alumina ceramics, but instead of this, the base plate 1 is made of single crystal silicon or the like having an oxide film deposited on its surface. It doesn't matter.

[0045]

According to the thermal head of the present invention, the sealing material for commonly covering the plurality of driver ICs mounted on the base plate is provided in the area between the driver ICs as compared with the mounting area of the driver ICs. Since the width is narrowed, the adhesion area of the sealing material to the base plate can be made as small as possible, and the thermal stress between the base plate and the sealing material can be suppressed to a small level. This effectively prevents the thermal head from warping in the longitudinal direction and maintains a high linearity of the heating element array, so that a good print can be formed.

Further, according to the thermal head of the present invention, the encapsulating material is continuously formed in the driver IC array direction without interruption, so that the liquid precursor is applied when the encapsulating material is formed. Work in a relatively short time,
In addition to being able to maintain high productivity of the thermal head, large bulges due to the surface tension of the liquid precursor are formed on the surface of the encapsulant only at both ends in the longitudinal direction.
Such a bulge is not formed between the adjacent driver ICs. Therefore, even if the running recording medium comes into contact with the sealing material, the running of the recording medium does not become extremely unstable, and the recording medium can always be stably run.

Further, according to the thermal head of the present invention, if an insulating layer having a groove corresponding to the pattern of the sealing material is deposited on the upper surface of the base plate prior to the formation of the sealing material, the sealing can be performed. When forming the stopper, the liquid precursor is effectively prevented from flowing into the groove formed by the insulating layer and attempting to spread to the outside of the groove, so that the liquid precursor has a pattern corresponding to the groove shape. Thus, the width of the sealing material can be controlled in each region with high accuracy.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view of the thermal head shown in FIG.

3 is a cross-sectional view of the thermal head of FIG.

FIG. 4 is a plan view of a conventional thermal head.

[Explanation of symbols]

1 ... Base plate, 2 ... Glaze layer, 3 ...
・ Heat generating element 3A ... Heat generating element array, 4 ... Circuit pattern, 5 ... Protective film, 6 ... Driver IC, 7 ...
..Sealing material, 8 ... Insulating layer

Claims (3)

[Claims]
1. A plurality of driver ICs are linearly arranged and mounted on a main surface of a base plate on which a row of heating elements is provided, with a predetermined gap therebetween, and the driver ICs are arranged in the direction of arrangement. A thermal head having a single encapsulating material continuously formed over a common area, the encapsulating material being narrower in a region between driver ICs than in a driver IC mounting region. The thermal head is characterized by the presence of
2. The width of the sealing material located in the mounting area of the driver IC is set to 30% to 80% of the width of the sealing material located in the area between the driver ICs. The thermal head according to claim 1.
3. The thermal head according to claim 1, wherein an insulating layer having a groove corresponding to the pattern of the sealing material is deposited on the upper surface of the base plate.
JP2002022526A 2002-01-30 2002-01-30 Thermal head Pending JP2003220725A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002022526A JP2003220725A (en) 2002-01-30 2002-01-30 Thermal head

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2002022526A JP2003220725A (en) 2002-01-30 2002-01-30 Thermal head

Publications (1)

Publication Number Publication Date
JP2003220725A true JP2003220725A (en) 2003-08-05

Family

ID=27745494

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2002022526A Pending JP2003220725A (en) 2002-01-30 2002-01-30 Thermal head

Country Status (1)

Country Link
JP (1) JP2003220725A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008207529A (en) * 2007-02-28 2008-09-11 Seiko Instruments Inc Thermal head, its manufacturing method, and thermal printer
WO2015029913A1 (en) * 2013-08-26 2015-03-05 京セラ株式会社 Thermal head and thermal printer provided with same
WO2018181734A1 (en) 2017-03-29 2018-10-04 京セラ株式会社 Thermal head and thermal printer

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008207529A (en) * 2007-02-28 2008-09-11 Seiko Instruments Inc Thermal head, its manufacturing method, and thermal printer
WO2015029913A1 (en) * 2013-08-26 2015-03-05 京セラ株式会社 Thermal head and thermal printer provided with same
CN105408119A (en) * 2013-08-26 2016-03-16 京瓷株式会社 Thermal head and thermal printer provided with same
JPWO2015029913A1 (en) * 2013-08-26 2017-03-02 京セラ株式会社 Thermal head and thermal printer equipped with the same
CN105408119B (en) * 2013-08-26 2017-08-29 京瓷株式会社 Thermal head and the thermal printer for possessing the thermal head
US9844950B2 (en) 2013-08-26 2017-12-19 Kyocera Corporation Thermal head and thermal printer provided with same
WO2018181734A1 (en) 2017-03-29 2018-10-04 京セラ株式会社 Thermal head and thermal printer

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