JPH05326114A - Printed heater and manufacture thereof - Google Patents

Abstract

PURPOSE:To enhance an insulation withstand voltage in the vicinity of a through-hole. CONSTITUTION:In this printed heater, a resistance heater element layer 5 is printed and formed on an insulative substrate 1 having a through-hole 3, and a conductor penetrating layer is continuously printed and formed on an obverse side and reverse side of the substrate 1 around the through-hole 3 and inside of the through-hole 3. This conductor penetrating layer is electrically conductive to the resistance heater element layer 5. An insulating glass layer 23 is printed and formed on the conductor penetrating layer on the obverse side and revers side of the substrate 1 around the through-hole 3 and inside of the through hole 3. In this type printed heater, an opening-expanding part which expands opening as approaching an opening part is further formed in the vicinity of each opening of the obverse side and reverse side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure and a manufacturing method of a printing heater which is a kind of heater used for fixing toner of a copying machine.

[0002]

2. Description of the Related Art In recent years, as a fixing heater used for fixing toner in an electronic copying machine, a paste such as a silver / palladium alloy powder is printed on a surface of an insulating substrate such as a slender ceramic and baked to form a slender line. A printing heater having a resistance heating element layer has been put into practical use. A voltage is applied to both ends of this line-shaped resistance heating element layer, and the toner is fixed by the heat generated by the resistance heating element layer. In the printing heater for fixing No. 3, the surface of the resistance heating element is covered with a glass layer.

As a kind of this printing heater, a through hole is provided in an elongated insulating substrate to electrically connect with a resistance heating element layer formed by printing on the front side of the substrate, and the front and back sides of the substrate around the through hole. In addition, the present inventors are developing a double-sided printing heater in which a conductor through layer is continuously formed by printing inside the through hole, and a back side conductive layer electrically connected to the conductor through layer is provided.

In this double-sided printing heater, a front electrode portion is formed at the end of the resistance heating element layer opposite to the through hole, and a back electrode is formed at the end of the back conductive layer opposite to the through hole. Portions are formed and both electrode portions are provided on one side of the substrate, so that the treatment of the lead wire to the heater is easy and safe.

[0005]

However, the conventional double-sided printing heater has a drawback that the reliability of electrical insulation is lower than that of the single-sided printing heater. That is, the electrical insulation of the conventional resistance heating element layer and various conductive layers is
This is done with a glass layer laminated on the surface of the resistance heating element layer and various conductive layers, but there is a drawback that the withstand voltage of this glass layer is lowered near the through hole. It is necessary to secure a DC voltage of 1500V or higher for the fixing heater everywhere, but 1500V is required near the through hole.
In some cases, it was less than V.

It is an object of the present invention to provide a printing heater having an improved structure in which the withstand voltage near the through hole is improved, and a method for manufacturing the same.

[0007]

In order to achieve the above object, the printing heater according to any one of claims 1 to 4 has an insulating substrate having through holes. A resistance heating element layer is formed by printing on the front side of the substrate. Conductor through layers are continuously printed on the front and back sides of the substrate around the through holes and inside the through holes, and the conductor through layers are electrically connected to the resistance heating element layer. An insulating glass layer is formed by printing on the front and back sides of the substrate around the through hole and on the conductor through layer inside the through hole. In such a printing heater, further, a widened portion is formed near the opening of the through hole to the front side of the substrate and the back side of the substrate so as to widen toward the vicinity of the opening.

Further, in the printing heater according to claim 5 or 6, instead of the substrate of the printing heater according to any one of claims 1 to 4, an expansion that expands as the conductor penetrating layer gets closer to the vicinity of the opening. It is characterized in that a part is formed.

Further, according to a seventh aspect of the present invention, there is provided a method of manufacturing a printing heater in which a resistance heating element layer is formed by printing on the front side of an insulating substrate having a through hole, and the resistance heating element layer is electrically connected to the resistance heating element layer. A step of continuously forming a conductor through layer on the front and back sides of the substrate around the through hole and on the inside of the through hole; and on the front and back sides of the substrate around the through hole and on the inside of the through hole, on the conductor through layer. Having a step of printing and forming an insulating glass layer, the step of printing and forming a conductor through layer, after the step of continuously printing and forming a conductor through layer on the substrate front side and back side around the through hole and inside the through hole, The conductor through layer is printed again on the substrate front side and the back side conductor penetrating layer around the through hole, so that the conductor penetrating layer is formed on the substrate front side and the substrate back side through hole. The vicinity of the opening, characterized by having a step of forming a diverging portion diverging toward the vicinity of the opening.

[0010]

In the printing heater according to any one of claims 1 to 6, when the insulating glass layer is formed by printing, since the expanding portion is formed near the opening of the through hole and expands as it approaches the opening. In addition, it is possible to suppress the drawback that the insulating glass layer becomes thin at the opening of the through hole and the insulation is deteriorated.

Further, in the method of manufacturing a printing heater according to a seventh aspect of the present invention, the step of printing the conductor through layer with the expanding portion that expands in the vicinity of the opening of the through hole is performed only twice. , Easy to form.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a fixing printing heater according to an embodiment, FIG. 2 is a sectional view taken along line BB in FIG. 1, FIG. 3 is a rear view, and FIG. 4 is A in FIG. It is a sectional view taken along the line A. In order to make the invention easier to understand, this sectional view is modified such that the characteristic portions are largely marked. The substrate (1) is a heat-resistant alumina ceramics (Al2O
It is a long flat plate made of 3) (about 270 mm x 7 mm x 1 mm in size). Two through holes (3) penetrating the front side and the back side of the substrate (1) are formed at one end on one side of the substrate (1) in advance. The opening of the through hole (3) has a beveled surface (4) with its corners shaved off. The inner diameter (diameter) of each through hole (3) is 0.4 mm. The inclined surface portion (4) is formed by cutting a region having a width of 0.1 mm around the through hole (3) at an angle of 45 degrees.

A strip-shaped resistance heating element layer (5) is provided on the front side of the substrate (1). The resistance heating element layer (5) is a conductive paste paint (made of silver-palladium alloy (Ag / P
d), or a metal (Ag /
Pd + RuO2)) is formed on the substrate (1) by printing and applying it in a strip shape along the longitudinal direction to a thickness of about 10 μm. The palladium contained in this alloy serves as an electrical resistance element, and the resistance value of the heating element is adjusted by the ratio. In this embodiment, the resistance value is 34 Ω [Ω], the current of 3 A flows by the voltage application of 100 V, and the heat generation amount is 300 W. One end of the resistance heating element layer (5) is formed wider on one side to form an electrode forming portion (7). The other end side of the resistance heating layer (5) is also formed to be wide including the periphery of the through hole (3), and constitutes a front side conductive base portion (9) for electrically conducting to the back side of the substrate (1). .. The strip-shaped part of the resistance heating layer (5) excluding the electrode forming part (7) and the front side conductive base part (9) generates heat.

A surface side electrode layer (11) for connecting to an external electrode (not shown) is formed on the surface of the electrode forming portion (7). This front side electrode layer (11) is provided in order to make contact electric resistance smaller than that of the resistance heating element layer (5), and is made of silver (Ag), silver platinum alloy (Ag / P).
A metal paste of t), gold (Au), platinum (Pt), or the like is used. That is, after the resistance heating element layer (5) is formed including the electrode formation portion (7) (after the resistance heating element paste is applied by printing and firing), these metal pastes are printed on the electrode formation portion (7). 3-5μ thick by coating and baking
The front electrode layer (11) is formed in a thickness of about m.

A front conductor penetration layer (13) for electrically conducting to the back side of the substrate (1) including the periphery of the through hole (3) is laminated on the surface of the front conduction ground portion (9). The front conductor penetration layer (13) is the front electrode layer (11).
The same material and the same screen printing are applied and fired at the same time. The thickness is also about 3 to 5 μm.

When the front conductor penetrating layer (13) is printed and applied around the through hole (3), the metal paste is also applied and printed inside the through hole (3) including the inclined surface portion (4). Inside the through hole (3), after the front conductor penetrating layer (13) is applied by printing around the through hole (3), the metal paste flows in by suction with a vacuum pump from the opposite side of the printed surface before firing. , Inner conductor penetration layer (1
5) is formed.

On the back side of the substrate (1), a strip-shaped back side conductive layer (17) having wide ends is provided, like the front side. The wide portion on one end side of the back side conductive layer (17), that is, the back side conductive layer (1) corresponding to the front side conductor penetrating layer (13).
The wide part of 7) constitutes the back conductor penetration layer (19) continuously conductively formed with the front conductor penetration layer (13) and the inner conductor penetration layer (15).

The back side conductive layer (17) is a front side electrode layer (11).
The same material as the front conductor penetrating layer (13) is applied by the same screen printing as that of the front conductor penetrating layer (13), and then baked to form the same.
The thickness is also about 3 to 5 μm.

The back side conduction layer (1) corresponding to the wide portion on the other end side of the back side conduction layer (17), that is, the front side electrode layer (11).
The wide part of 7) constitutes a back electrode layer (21) for connecting to an external electrode (not shown). The back electrode layer (21) is formed at a position deviated from the front electrode layer (11).

The surface of the strip-shaped portion of the resistance heating element layer (5) is coated with a glass material having a high electric insulation property to form an insulating glass layer (23). The insulating glass layer (23) has borosilicate glass as a main component, and for example, an insulating glass paste PLS3310 manufactured by Nippon Electric Glass Co., Ltd. is applied by printing and baked to have a thickness of about 10 μm.
It was formed in. The insulating glass using PLS3310 has an electric breakdown voltage of 2000 V under the condition that a DC voltage is applied when the thickness is 35 μm. The insulating glass paste PLS3310 is applied by the screen printing method after the resistance heating element layer (23) is formed and then fired.

The insulating glass layer (23) is applied not only to the strip-shaped portion of the resistance heating element layer (5) but also to the boundary portion of the electrode layer (11). This is because the temperature gradient near the boundary between the strip-shaped portion of the resistance heating element layer (5) and the electrode forming portion (7) is steep, so that the resistance heating element layer (5) in the vicinity is likely to be disconnected, This risk is reduced by covering this part with an insulating glass layer (23). In addition, the electrode layer (1
Around the boundary of 1) (on the side of the strip portion of the resistance heating element layer (5)) is easily peeled off due to the effect of heat generation, but this risk is also reduced by covering this portion with the insulating glass layer (23). ..

The insulating glass layer (23) is a back conductive layer (1).
7), front conductor penetration layer (13), inner conductor penetration layer (1)
5) and also on the surface of the back conductor penetrating layer (19). When the toner image formed on the copy paper is fixed by the heat of the heater, the insulating glass layer (23) performs an operation of bringing this surface of the heater into close contact with the paper and sliding, so that the resistance heating layer (5) and The purpose is to protect copy paper, reduce sliding friction, and ensure electrical insulation.

In the printing heater having the above-mentioned structure, since the expanded portion such as the slope portion (4) which expands as it approaches the opening is formed near the opening of the through hole (3), the insulating glass layer ( 23) When screen printing
It is possible to suppress the drawback that the insulating glass layer (23) becomes thin at the opening of the through hole and the insulation is deteriorated.

In the above embodiment, the electric breakdown voltage at the edge of the through hole (3) is 2000 V in the flat portion,
Since it is 1900 V, no large decrease in the electric breakdown voltage is observed. On the other hand, when a printing heater without forming the inclined surface portion (4) was manufactured under the same conditions and the electric withstand voltage at the edge of the through hole (3) was measured, it was greatly reduced to 400V. From this, it was found that the formation of the inclined surface portion (4) can prevent the decrease of the electric breakdown voltage. The reason for this is that if the widened portion such as the inclined surface portion (4) is not formed, the insulating glass layer (23) may be formed by screen printing at the edge or corner of the opening of the through hole when the insulating glass layer (23) is formed by screen printing. It is presumed that the film thickness of (23) becomes thin and the electrical insulating property is deteriorated at this portion.

In fact, when a 10 μm thick insulating glass layer is applied to a printing heater having no slope (4), the insulating glass layer has a thickness of 3 to 3 at the edge of the opening of the through hole or at the corner. It was confirmed that the thickness was lowered to 5 μm.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view of the main part of the substrate near the through hole of the printing heater of the second embodiment. The structure of the through hole is only slightly different from that of the first embodiment, and FIGS. 1, 2, and 3 showing the overall structure of the printing heater are the same as those of the first embodiment. Therefore, the description of the same configuration as the first embodiment is omitted.

The through hole (3) formed in the substrate (1) has a cross section different from that of FIG. On the surface of the substrate (1), as in the first embodiment, the front side conductive underlayer (9) is formed by screen printing and firing. After the front-side conductive underlayer (9) is formed, on the front-side conductive underlayer (9), inside the through hole (3), near the through-hole (3) on the back surface of the substrate, the front-side conductor through layer (13a) and the inside are respectively formed. A conductor penetrating layer (15) and a back conductor penetrating layer (19) are formed. Front conductor penetration layer (13a)
After being screen-printed and applied, the inside of the through hole (3) is evacuated from the back side so that the metal paste wraps around the inside of the through hole (3) from the front side of the substrate. After this, the back conductor penetrating layer (19) is further screen-printed and applied. Then, the front conductor through layer (13a), the inner conductor through layer (15), and the back conductor through layer (19) are simultaneously fired.

If the insulating glass layer (23) is formed immediately after this, the conventional example itself is obtained, and the insulating glass layer (23) becomes thin at the edge of the opening of the through hole (3), and the insulating performance deteriorates. Have. In this example, thereafter, the second front conductor through layer (13b) was again provided on the front conductor through layer (13a) on the front side of the substrate (1) and the back conductor through layer (1).
The second back side conductor penetrating layer (19b) is screen-printed and applied on 9a), and then baked. After screen-printing / applying the first front-side conductor penetrating layer (13a), the second front-side conductor penetrating layer (13b) was screen-printed / applied in a process in which the inside of the through-hole (3) was evacuated from the back side. I won't do it later. As a result, the protruding portions (13c) and (19c) protruding to the through hole (3) are provided at the open ends of the through holes (3) of the second front conductor penetrating layer (13b) and the second back conductor penetrating layer (19b). ) Is formed.
The protrusions (13c) and (19c) are the first front conductor penetrating layer (13a) and the first back conductor penetrating layer (19).
Due to the presence of the base of a) and the fact that the vacuum is not drawn, the relatively large slope part (4) is pushed out (13).
c) and (19c) are formed integrally.

After this, an insulating glass layer (23) is formed. After the insulating glass paste is screen-printed and applied on the front side, the inside of the through hole (3) is evacuated so that the insulating glass paste on the front side wraps around the inside of the through hole (3). After this, an insulating glass paste is screen-printed and applied on the back side as well, and then baked to form an insulating glass layer (23).

When the insulating glass paste is applied, the second front conductor penetrating layer (13b) and the second back conductor penetrating layer (19b) are already formed at the open ends of the through holes (3).
Thus, since the inclined surface portion (4) is formed, it is prevented that the insulating glass layer (23) becomes thin at the opening end of the through hole (3) and the insulation performance is deteriorated.

Further, in the above embodiment, the inclined surface portion (4) can be easily formed by only applying the front side conductor penetration layer and the back side conductor penetration layer twice, without special processing of the substrate (1). it can.

In the second embodiment, the front conductor through layer and the back conductor through layer are formed twice by coating.
It may be three times or more.

Further, in each of the above two embodiments, two through holes (3) are provided at one place, but one may be provided. Further, although the resistance heating element layer (5) is one, it can be applied to a branching element in the middle. Further, in the embodiment, the insulating glass layer (23) is formed excluding the front side electrode layer (11) and the back side electrode layer (21), but when it is necessary to secure electrical insulation, only the front side is insulated. The glass layer (23) may be provided. In this case, it is not necessary to provide the slope portion (4) in the opening on the back side of the through hole (3).

[0034]

In the printing heater of the present invention, since the expanded portion is formed near the opening of the through hole so as to expand as it approaches the opening, the through hole is formed when the insulating glass layer is formed by screen printing. The thickness of the insulating glass layer does not become thin at the openings of the above, and therefore, the drawback of lowering the electrical insulation can be suppressed.

Further, according to the method of manufacturing a printing heater of the present invention, the step of printing the conductor through layer with the expanded portion which expands in the vicinity of the opening of the through hole as it approaches the opening is performed only twice. It can be easily formed.

[Brief description of drawings]

FIG. 1 is a plan view of a printing heater for fixing according to a first embodiment.

FIG. 2 is a sectional view taken along line BB in FIG.

FIG. 3 is a rear view of the fixing print heater according to the first embodiment.

FIG. 4 is a sectional view taken along the line AA in FIG.

FIG. 5 is a sectional view of an essential part of a printing heater according to a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 3 ... Through hole, 4 ... Slope part 5 ... Resistance heating element layer, 7 ... Electrode formation part, 9 ...
.. Front side conductive base layer 11 ... Front side electrode layer, 13 ... Front side conductor through layer 13a ... First front side conductor through layer, 13b ... Second front side conductor through layer 13c ... Projection Part, 15 ... Inside conductor penetration layer, 17 ... Back side conduction layer 19 ... Back side conductor penetration layer, 19a ... First back side conductor penetration layer 19b ... Second back side conductor penetration layer, 19c ... Protruding part 21 ... Back side electrode layer, 23 ... Insulating glass layer

Claims (7)

[Claims] 1. An insulating substrate having a through hole,
A resistance heating element layer printed on the front side of the substrate and a conductor penetrating electrically connected to the resistance heating element layer and continuously printed on the front and back sides of the board around the through hole and inside the through hole. In a printing heater comprising a layer, an insulating glass layer printed on a conductor through layer on the front and back sides of the substrate around the through hole, and on the inside of the through hole, the through hole is provided on the front side and the back side of the substrate. A printing heater characterized in that a widened portion is formed near the opening of the hole so as to widen near the opening. 2. The printing heater according to claim 1, wherein the expanded portion forms a slope. 3. The substrate has an elongated shape having both ends, the resistance heating element layer has a band-shaped portion connecting both ends of the substrate, and the through hole is formed at one end of the substrate,
2. The printing heater according to claim 1, further comprising a back side conductive layer which is electrically connected to the conductor penetrating layer and has a band-shaped portion connecting both ends of the board formed on the back side of the substrate. 4. A front electrode portion is formed at an end of the resistance heating element layer opposite to the through hole, and a back electrode portion is formed at an end of the back conductive layer opposite to the through hole. The printing heater according to claim 3, wherein: 5. An insulating substrate having a through hole,
A resistance heating element layer printed on the front side of the substrate and a conductor penetrating electrically connected to the resistance heating element layer and continuously printed on the front and back sides of the board around the through hole and inside the through hole. In a printing heater comprising a layer, a substrate front side and a back side around the through hole, and an insulating glass layer printed and formed on a conductor penetrating layer on the inside of the through hole, the conductor penetrating layer is provided on the board front side and the substrate back side. A printing heater characterized in that an expanding portion is formed near the opening of the through hole and expands as it approaches the opening. 6. The conductor penetrating layer has a protruding portion protruding toward the through hole in the vicinity of the opening of the through hole, and the widened portion is formed in the protruding portion. Printing heater. 7. A step of printing a resistance heating element layer on the front side of an insulating substrate having a through hole, electrically connecting with the resistance heating element layer, and a front side and a back side of the substrate around the through hole. A printing heater having a step of continuously printing and forming a conductor through layer inside the through hole, and a step of printing and forming an insulating glass layer on the conductor through layer on the front and back sides of the substrate around the through hole and inside the through hole. In the manufacturing method, the step of printing and forming the conductor through layer is performed after the step of continuously printing and forming the conductor through layer on the front and back sides of the substrate around the through hole and on the inside of the through hole. By forming a conductor through layer on the front and back sides of the substrate by printing, the conductor through layer is formed near the through holes on the front and back sides of the substrate. A method of manufacturing a printing heater, comprising the step of forming an expanded portion that expands as it approaches the mouth.