JPH0863015A - Fixing device - Google Patents

Abstract

PURPOSE: To prevent a recording paper from being stained and to prevent the bleeding of an image from occurring by enhancing fixing performance. CONSTITUTION: A glaze layer 10 is provided on an insulating substrate 9 and build-up parts 10a and 10b are respectively arranged at both side ends of the layer 10 almost in parallel at the interval of 1mm-7mm. Besides, a heating resistor 11 is formed in an area held by both build-up parts 10a and 10b of the layer 10 in a belt state. Then, a fixing device 6 is constituted of a heater for fixing 7 consisting by arranging a protecting film on the layer 10 so as to cover the resistor 11 and a press-contact roller 8 whose outside diameter is set to be 16mm-800mm so as to bring the heater 7 into press-contact in order to make both build-up parts 10a and 10b of the layer 10 abut on the roller 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device mounted on an electrophotographic printer, a facsimile or the like, and in particular, a strip-shaped glaze layer is provided on a long insulating substrate and a heating resistor is formed on the glaze layer. The present invention relates to a fixing device including a fixing heater including the above and a pressure contact roller disposed in the fixing heater.

[0002]

2. Description of the Related Art In JP-A-59-68766, various specifications of a thin film type thermal head and a thick film type thermal head, which are known as a thermal recording head for thermal recording, are used for a fixing heater, and this fixing It has been proposed to apply a pressure roller to a heater for recording paper, convey a recording paper carrying an unfixed toner image between them, and fix the recording paper with this fixing heater.

However, although the publication proposes to use the thermal head specification for the fixing heater, it does not describe any specific structure of the fixing heater.

Also, Japanese Patent Laid-Open No. 2-65086 proposes a fixing heater with a thermal head specification. That is, FIG. 7 is a cross-sectional view of the fixing heater 1, in which a glaze layer 3 is provided on the upper surface of an elongated flat plate-shaped substrate 2 made of alumina ceramics having a length of 300 mm and a width of 8 mm.
Further, an elongated electric heating element 4 is arranged on the glaze layer 3,
The surface of the electric heating element 4 and the surface of the glaze layer 3 are covered with a vitreous protective layer 5.

[0005]

However, according to the fixing heater 1 having the above-described structure, since the electric heating element 4 is provided on the top of the glaze layer 3, the contact property with the recording paper is increased. On the other hand, there is a problem that the contact area becomes small, which makes it difficult to conduct heat widely and reduces the heat transfer efficiency.

Further, when the contact area becomes small as described above, it is difficult to make the contact with a uniform width in the longitudinal direction of the fixing heater 1, and there is a problem that uneven heating occurs in that direction.

Therefore, due to such a problem, the fixing on the recording paper is not uniform, and the non-fixed toner is removed due to the fixing unevenness, so that the image on the recording paper is not sufficiently formed thereafter, and the unfixed toner causes the unfixed toner to be formed. The recording paper was contaminated or the image was blurred.

The present invention has been completed in view of the above circumstances, and an object of the present invention is to form an image faithfully on a recording paper by fixing an unfixed toner image effectively and uniformly, and This is to prevent contamination or blurring of the image.

[0009]

According to a first aspect of the present invention, there is provided a fixing device in which strip-shaped glaze layers are arranged on a long insulating substrate along a longitudinal direction thereof, and raised portions are formed at both ends of the glaze layers. Are provided substantially in parallel at an interval of 1 mm to 7 mm, a heating resistor is formed in a band shape in a region sandwiched by both raised portions on the glaze layer, and a protective film is formed on the glaze layer so as to cover the heating resistor. It is characterized in that it is composed of a fixing heater having electrodes arranged at both ends of the heat generating resistor, and a pressure roller having an outer diameter of 16 mm to 800 mm to press the fixing heater.

According to a second aspect of the present invention, the glaze layer is formed by applying a glass paste on an insulating substrate and then printing and baking the paste.

[0011]

In the fixing device according to the first aspect, the glaze layer is provided on the elongated insulating substrate, and the raised portions are arranged at both ends of the glaze layer at an interval of 1 mm to 7 mm,
Further, the heating resistor is formed in a band shape in a region sandwiched by both raised portions on the glaze layer, and the outer diameter of the pressure contact roller is set to 16 mm to 800 mm so as to fit the fixing heater of this structure. are doing. In the fixing device having such a structure, the pressure contact roller can contact the raised portion on the glaze layer and can sufficiently press the heat generating resistor, whereby the recording paper carrying the unfixed toner image therebetween. When the sheet is conveyed, the degree of contact of the pressure contact roller with the heat-generating resistor is increased due to the fitting state of the concave portion formed in the fixing heater and the convex portion of the pressure roller itself, and the contact area is widened to increase the heat generating resistance. The body can conduct heat widely, and the heat transfer efficiency is significantly enhanced. Moreover, the fixing heater can be contacted with a uniform width in the longitudinal direction, and heating unevenness does not occur in that direction.

Therefore, since the unfixed toner image can be effectively and uniformly fixed, the toner image on the recording paper can be reproduced faithfully to the image, the recording paper is not contaminated, and the image does not bleed.

According to the second aspect of the present invention, the glaze layer is formed by applying a glass paste on the insulating substrate and then printing and baking it. According to this forming method, the peripheral edge rises after firing and becomes thicker by about 10 to 15 μm than the central flat portion. By adjusting the manufacturing conditions, the raised portions at both ends are 1 mm to 7 m.
It is possible to easily create the glaze layers arranged in parallel at intervals of m.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic cross-sectional view showing the basic structure of a long fixing device 6, and FIG. 2 is a plan view of a fixing heater 7 which is a main part of the fixing device 6. FIG. 3 is a cross-sectional view taken along the section line X-X shown in FIG. FIG. 4 is a vertical cross-sectional view showing the end structure of the fixing heater 7.

According to FIG. 1, the fixing device 6 comprises a fixing heater 7 and a pressure contact roller 8, and the fixing heater 7 is a long insulating substrate 9 made of ceramics such as alumina or zirconia. A glass glaze layer 10 formed on the insulating substrate 9 and further the glaze layer 1
0 and a heating resistor 11 on the upper side. The heating resistor 11 is made of tantalum nitride, titanium oxide, ruthenium oxide,
It is provided by sputtering or printing firing with a resistor material such as tungsten. The pressing roller 8 is arranged on the fixing heater 7 having such a structure, and the recording paper 12 carrying the unfixed toner image is conveyed between the fixing heater 7 and the pressing roller 8. The pressure contact roller 8 is formed by applying a flexible elastomer layer to the outer peripheral surface of a cylindrical metal body serving as a core. In this embodiment, the elastomer layer is made of silicon rubber or the like.

According to FIGS. 2 and 3 showing the specific structure of the fixing heater 7, the belt-shaped glaze layer 10 is provided so that the raised portions 10a and 10b are parallel to each other at both ends thereof. The glaze layer 10 is provided by applying a glass paste by a screen printing method or a spray and then firing it.
The heating resistor 11 is formed in a band shape in the recessed region between 10b. Further, electrode portions 14 made of aluminum, gold, silver or the like are provided on both ends of the heating resistor 11 by a combination of sputtering and photolithography, and the glaze layer 10 is further covered so as to cover the heating resistor 11. The protective film 13 is provided on the. The protective film 13 is made of silicon nitride, silicon carbide, silicon oxide or the like, and is provided by sputtering. Alternatively, if it is made of lead borosilicate or the like, it is provided by printing firing.

According to FIG. 4 showing the vicinity of the electrode portion 14, in disposing the protective film 13, a part of the electrode portion 14 is not covered, and the connection cable 16 is provided on the exposed region with the solder 15 interposed therebetween. To provide.

In the present invention, when the pressure roller 8 having an outer diameter of 16 mm to 800 mm is used in the fixing device 6 having the above structure, the raised portions 10a, 1
The interval (width) W1 of 0b is 1 mm to 7 mm, preferably 2 m
When set to m to 5 mm, when the pressure contact roller 8 presses the heat generating resistor 11 through the recording paper 12, the recording paper 12 sufficiently contacts the heat generating surface of the heat generating resistor 11 and the contact area is large. As a result, the heat generating resistor 11 conducts heat widely, and its heat transfer efficiency is remarkably improved. As shown in FIG. 1, since a flexible elastomer layer is coated on the outer peripheral surface of the pressure roller 8, there is a recording paper contact width W2 at an interval slightly larger than the width W1 due to its elasticity.

This contact width of the recording paper is the nip width (effective contact width) of the recording paper 12 with the heating resistor 11, and according to experiments conducted repeatedly by the present inventor, this width W2 is 1.5.
It was confirmed that in the range of mm to 7.5 mm, the heat transfer efficiency becomes optimum in the relation between the diameter of the pressure contact roller 8 in the predetermined range and the width W1. Furthermore, the width W3 of the strip-shaped heating resistor 11 is the same as or smaller than the width W1 and is preferably 1 mm to 7 mm. Here, as the width W1 and the width W3 are set in the same range, the strip-shaped heating resistor 11 is formed on the raised portions 10a, 10 and 10.
It may be provided in the entire depressed region between b.

Next, in the present invention, the glaze layer 1 is used.
0 is preferably formed by screen printing and firing. That is, with this forming method, the glaze layer 10
The glass paste to be the base of is applied by the screen printing method, then baked at a temperature of about 1000 ° C., and then
When cooled to room temperature, the peripheral edge rises after this firing,
It is well known to those skilled in the art that the thickness is about 10 to 15 μm thicker than the central flat portion.

According to the experiments repeated by the present inventor,
When the width W4 of the glaze layer 10 is set to fall within the range of 3.5 mm to 13 mm, the glaze layer 10 generally has the raised portions 10a and 10b, although it depends on the material of the glaze and firing conditions. Its width W1 is 1
It becomes easy to set it to mm to 7 mm.

Further, according to this forming method, as shown in FIG. 4, since the raised portions 10c are formed at both ends in the longitudinal direction of the glaze layer 10, according to the experiments conducted by the present inventor repeatedly, the long dimension thereof is obtained. Is preferably 7 to 12 mm larger than the size of the pressing roller 8 in the longitudinal direction, whereby the pressing roller 8 hits a flat region within the longitudinal dimension of the glaze layer 10 and, as a result, the fixing heater 7 It was possible to make uniform contact over the longitudinal direction of the and evenly, and heating unevenness did not occur in that direction.

Experimental examples will be described below. (Example 1) In this example, a glass paste is applied by a screen printing method on an insulating substrate 9 made of alumina ceramics having a length of 300 mm and a width of 8 mm, and then about 10
It was fired at a temperature of 00 ° C. and then cooled to room temperature, whereby the peripheral edge of the glaze layer 10 swelled and became thicker by about 12 μm than the central flat portion. The width W4 of the glaze layer 10 is 4.1 mm, and the width W4
1 is 1.6 mm, and its longitudinal dimension is 230 mm.
Met. Then, a strip-shaped heating resistor 11 (width W is made of tantalum nitride is formed in the depression region of the glaze layer 10.
3 = 0.6 mm) by sputtering and photolithography.

Next, aluminum electrode portions 14 are provided on both ends of the heating resistor 11, and the heating resistor 11 is further provided.
A protective film 13 of silicon nitride was formed on the glaze layer 10 by sputtering so as to cover the film. Subsequently, as shown in FIG. 4, the connection cable 16 was provided via the solder 15.

With respect to the fixing device 6 thus obtained, a pressure roller 8 having an outer diameter of 55 mm (longitudinal dimension is 220 m)
When m) is used, the recording paper 12 makes sufficient contact with the heat generating surface of the heat generating resistor 11 and the contact area becomes large, whereby the heat generating resistor 11 conducts heat widely and its heat transfer efficiency is increased. Significantly improved. The nip width W2 was 1.8 mm.

Therefore, the fixing temperature of the fixing device 6 is set to 20.
The recording paper 12 carrying the unfixed toner image is conveyed to 0 ° C., and the recording paper 1 is conveyed by the fixing device 6.
2 is fixed, the toner image on the recording paper 12 can be reproduced faithfully to the image, and the recording paper 12 is not contaminated.
In addition, blurring did not occur in the image.

(Example 2) In this example, when the fixing device 6 of (Example 1) is manufactured, a fixing heater 7 for the glaze layer 10 and the heating resistor 11 having the following dimensions is prepared, and When the pressure contact roller 8 having the following outer diameter is used and the other conditions are set the same as in (Example 1) and various fixing devices 6A, 6B, 6C, 6D, 6E, and 6F are formed, In the same manner, the toner image on the recording paper 12 can be reproduced faithfully to the image, the recording paper 12 is not contaminated, and the image does not bleed.

Fixing device 6A -Glaze layer 10 Rising height of peripheral edge: 10 μm compared to the central flat portion Width W1: 1.0 mm Width W4: 3.5 mm-Heating resistor 11 Width W3: 0.6 mm-Pressing roller 8 Outer diameter: 25 mm Width W2: 1.1 mm.

Fixing device 6B -Glaze layer 10 Rising height of peripheral edge: 15 μm as compared with the central flat portion Width W1: 1.6 mm Width W4: 4.1 mm-Heating resistor 11 Width W3: 0.6 mm-Pressing roller 8 Outer diameter: 43 mm Width W2: 1.8 mm.

Fixing device 6C -Glaze layer 10 Rising height of peripheral edge: 12 μm compared with the central flat portion Width W1: 3.0 mm Width W4: 5.5 mm-Heating resistor 11 Width W3: 2.0 mm-Pressing roller 8 Outer diameter: 188 mm Width W2: 2.5 mm.

Fixing device 6D -Glaze layer 10 Rising height of peripheral edge: 12 μm compared with the central flat portion Width W1: 5.0 mm Width W4: 7.5 mm-Heating resistor 11 Width W3: 4.0 mm-Pressing roller 8 Outer diameter: 520 mm Width W2: 5.2 mm.

Fixing device 6E -Glaze layer 10 Rising height of peripheral edge: 12 μm compared to the central flat portion Width W1: 7.0 mm Width W4: 9.5 mm-Heating resistor 11 Width W3: 5.0 mm-Pressing roller 8 Outer diameter: 800 mm Width W2: 7.5 mm.

Fixing device 6F -Glaze layer 10 Rising height of peripheral edge: 15 μm compared to the central flat portion Width W1: 7.0 mm Width W4: 9.5 mm-Heating resistor 11 Width W3: 5.0 mm-Pressing roller 8 Outer diameter: 800 mm Width W2: 7.5 mm.

(Example 3) Comparative Example In this example, in fixing with the fixing device 6 of (Example 1), the pressure contact roller 8 having an outer diameter of 850 mm was used, and the other conditions were the same as those of (Example 1). When the toner image was set and fixed in the same manner, the toner image on the recording paper 12 was not sufficiently fixed, the recording paper 12 was contaminated, and bleeding occurred in the image.

(Example 4) Comparative Example In this example, in fixing by the fixing device 6 of (Example 1), the pressure contact roller 8 having an outer diameter of 14 mm was used, and the other conditions were set to be the same as those of (Example 1). Then, when the toner image is fixed in the same manner, the toner image on the recording paper 12 is not sufficiently fixed, the recording paper 12 is contaminated, and the image is blurred.

(Example 5) Comparative Example In this example, when fixing was performed by the fixing device 6B of (Example 2), fixing was similarly performed using the pressure contact roller 8 having an outer diameter of 850 mm. The toner image was not sufficiently fixed, the recording paper 12 was contaminated, and the image was blurred.

(Example 6) Comparative Example In this example, in fixing with the fixing device 6D of (Example 2), a pressure roller 8 having an outer diameter of 14 mm was used.
When it was similarly fixed, the toner image on the recording paper 12 was not sufficiently fixed, the recording paper 12 was contaminated, and bleeding occurred in the image.

(Example 7) Comparative Example The fixing device 6a shown in FIG. 5 is different from the fixing device 6 of (Example 1) in that the shape of the glaze layer 10 is changed to form a semi-cylindrical shape (width W = 2. 1 mm), and the other fixing device 6 (example 1)
It shows the case of the same structure as. The fixing device 6 of FIG.
The members having the same function among the members shown in FIG. Then, when fixing is performed in the same manner as in (Example 1), the width W2
Was 0.4 mm, the toner image on the recording paper 12 was not sufficiently fixed, the recording paper 12 was contaminated, and bleeding occurred in the image.

(Example 8) Comparative Example The fixing device 6b shown in FIG. 6 is different from the fixing device 6 of (Example 1) in that the shape of the glaze layer 10 is changed so that the width W4 of both raised portions 10a and 10b is 20 mm. In the other example, the fixing device 6 is made larger, and the other parts have the same structure as the fixing device 6 of (Example 1). The members having the same function among the members shown in the fixing device 6 in FIG. 1 are designated by the same reference numerals. Then, when fixing was performed in the same manner as in (Example 1), the width W2 was 0.5 mm, the toner image on the recording paper 12 was not sufficiently fixed, the recording paper 12 was contaminated, and bleeding occurred in the image. .

(Example 9) Comparative Example Next, as the fixing device 6b shown in FIG. 6, as compared with the fixing device 6D of (Example 2), the shape of the glaze layer 10 was changed and the width W4 of both raised portions 10a, 10b was changed. The width W2 is 3.0 mm when the fixing is performed in the same manner even when the fixing device 6D has the same structure as the fixing device 6D.
However, the toner image on the recording paper 12 was not sufficiently fixed, the recording paper 12 was contaminated, and bleeding occurred in the image.

The present invention is not limited to the above embodiments, and various modifications and improvements may be made without departing from the scope of the present invention.

[0042]

As described above, according to the fixing device of the first aspect of the present invention, the pressure contact roller can contact both the raised portions on the glaze layer and can sufficiently press the heat generating resistor. When the recording paper carrying the unfixed toner image is conveyed between the two, the contact degree of the pressure contact roller with the heating resistor is increased, and the contact area is widened, whereby the heating resistor conducts heat widely. The heat transfer efficiency is remarkably enhanced, and furthermore, the fixing heater can be contacted with a uniform width over the longitudinal direction, and heating unevenness does not occur in that direction. As a result, an unfixed toner image can be obtained. Since the toner can be effectively and uniformly fixed, the toner image on the recording paper can be reproduced faithfully to the image, and the recording paper is not contaminated or the image does not bleed.

According to the second aspect of the present invention, the glass paste is applied onto the insulating substrate and then printed and baked to adjust the manufacturing conditions to form a desired glaze layer. It was possible to easily create a glaze layer in which raised portions were arranged in parallel on both ends at intervals of 1 mm to 7 mm, and as a result, manufacturing efficiency was improved and manufacturing cost could be reduced.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view in cross section showing a basic configuration of a fixing device of the present invention.

FIG. 2 is a plan view of a fixing heater in the fixing device of the embodiment.

FIG. 3 is a cross-sectional view taken along the section line XX shown in FIG.

FIG. 4 is a vertical cross-sectional view showing an end structure of a fixing heater in the fixing device of the embodiment.

FIG. 5 is a schematic cross-sectional view illustrating a basic configuration of a fixing device according to a comparative example.

FIG. 6 is a schematic cross-sectional view showing a basic configuration of a fixing device of a comparative example.

FIG. 7 is a cross-sectional view of a conventional fixing heater.

[Explanation of symbols]

 6 Fixing Device 7 Fixing Heater 8 Pressing Roller 9 Insulating Substrate 10 Glaze Layers 10a, 10b Raised Part 11 Heating Resistor 13 Protective Film

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B41J 2/335 H05B 3/20 305

Claims (2)

[Claims] 1. A strip-shaped glaze layer is arranged on a long insulating substrate along the longitudinal direction thereof, and raised portions are provided at both ends of the glaze layer in parallel at intervals of 1 mm to 7 mm, respectively. A heating resistor is formed in a band shape in a region sandwiched by both raised portions on the glaze layer, and a protective film is arranged on the glaze layer so as to cover the heating resistor,
A fixing heater having electrodes at both ends of the heating resistor and an outer diameter of 16 mm to press the fixing heater into contact with each other.
A fixing device composed of an 800 mm pressure contact roller. 2. The fixing device according to claim 1, wherein the glaze layer is formed by applying a glass paste on an insulating substrate and then printing and baking the glass paste.