JPH09190097A - Heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of an image with tailing by forming the appearance shape (pattern) of the heating resistor of a heating body, at an angle with the moving direction of a heated body. SOLUTION: The pattern (appearance shape) of the heating resistor 2 is formed at an angle of θ with an X axis, in such a manner that a certain position in the short side direction of a ceramic substrate 3 is used as the X axis, a certain position in the long side direction is used as a Y axis and the intersection is used as an origin. In other words, in the figure, the pattern is formed on the ceramic substrate 3, with an inclination to the left. Then, a voltage is applied to electrodes 1a and 1b, to generate heat in the heating resistor 2. When the heated body 8 is moved in the width direction (the direction of the arrow Q) of a heating body 10 in an electrophotographic system printer as an image forming device using such a heating device, vapor, etc., generated in the vicinity of the heating resistor 2 can be jetted at the angle with the upstream side in the moving direction of the heated body 8, because the heating resistor 2 is formed with an angle of θ.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device having a heating body for heating an object to be heated, and more particularly to the structure of the heating body.

The present invention also relates to a heating device used in a fixing unit for permanently fixing an unfixed toner image in an electrophotographic system in an image forming apparatus to a body to be heated.

[0003]

2. Description of the Related Art As a conventional method for heating an object to be heated of this kind, a heat roller method has been proposed. However, this method has to maintain a high temperature all the time, which consumes a large amount of energy and is contrary to energy saving. In addition, even during standby, heat is released into the machine, causing a problem of temperature rise. Further, it takes time to heat the roller to a temperature suitable for heating the object to be heated.

Therefore, there is a method in which a pattern of a resistance heating element is provided on a ceramic substrate to form a heating element, and the resistance heating element is heated to heat an object to be heated through a thin film. It has been proposed in the publication.

In this method, since the temperature of the heating element rises in a short time, even if the paper to be heated is immediately passed, the heating element reaches the temperature necessary for reaching the fixing portion. Can be heated.

Moreover, since heating is not performed during standby, there is no temperature rise inside the machine and no energy is consumed.

[0007]

As a heating element used in such a heating device, there is one in which a resistance heating element is formed on one side of a ceramic base material as a base. Figure 7
(A) is an example of the heating body 100 used conventionally. In this figure, the electrodes 101a and 101b are on one side (left side in the figure) of the ceramic base material 102, and the pattern (appearance shape) of the resistance heating element 103 is formed in a straight line in the longitudinal direction of the ceramic base material 102. In the longitudinal direction of the resistance heating element 103, the left end and the electrode 101a are connected by a conductor 104a, and the right end and the electrode 101b are connected by a conductor 104b. The conductor patterns are formed in a straight line and in parallel. doing.

An example of a heating device using such a heating element is shown in FIG. 7 (b).

That is, this heating device is provided with the heating element 100.
Is fixedly supported at a predetermined position, a heat resistant film 105 is provided on the side of the resistance heating element 103 of the heating element 100, and a pressure roller 106 as a pressure member is pressed against the surface of the heat resistant film 105. is there.

The heat-resistant film 105 is movable in the direction of the arrow in the figure, and as the heat-resistant film 105 moves, the heated object 108 on which the unfixed toner image 107 is formed is added to the heat-resistant film 105. Pressure roller 10
The resistance heating element 1 of the heating element 100 introduced into the nip between
The thermal energy of 03 is applied to the object 108 to be heated through the heat resistant film 105 to fix the toner image.

In an electrophotographic printer as an image forming apparatus using such a heating device, when the heated object 108 moves in the width direction (direction of arrow Q in FIG. 7A), the heated object 108 is Moisture contained therein is thermally expanded and steam is blown out in the y1 direction. The steam or the like blown off is blown off to the unfixed toner image 107, and a trailing image is generated. Especially,
The unfixed toner image 107 that continues laterally with respect to the moving direction of the object 108 to be heated is the water vapor 10 as shown in FIG. 7B.
It becomes a shape that prevents the balloons such as 9 and becomes a cause of the trailing image.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art.
An object of the present invention is to provide a heating device and an image forming apparatus capable of preventing a trailing image.

[0013]

In order to achieve the above object, in the first invention according to the present application, a heat-resistant film is provided on a heating body fixedly supported and provided with a resistance heating body on a base. Through a pressure member to the surface of the heat-resistant film, and introduced between the heat-resistant film and the pressure member along with the traveling movement of the heat-resistant film, the heat energy of the resistance heating element to the heat resistance In a heating device for applying to a heated object through a film, the resistance heating element has an outer shape that forms an angle with a moving direction of the heated object.

In order to achieve the above object, in the second invention according to the present application, a heat-resistant film is fixed to and supported by a heating element having a resistance heating element provided on a substrate, and the heat-resistant film is interposed between the heating elements. A pressure member is brought into pressure contact with the film surface and introduced between the heat resistant film and the pressure member as the heat resistant film travels, and the heat energy of the resistance heating element is heated through the heat resistant film. In the heating device for applying to the body, the external shape of the resistance heating element is discontinuous and has an angle with respect to the moving direction of the object to be heated.

In order to achieve the above object, in the third invention according to the present application, a heat-resistant film is provided on a heating body which is fixedly supported and provided with a resistance heating body on a substrate, through the heat-resistant film. A pressure member is brought into pressure contact with the film surface and introduced between the heat resistant film and the pressure member as the heat resistant film travels, and the heat energy of the resistance heating element is heated through the heat resistant film. In a heating device for applying to a body, the surface of the resistance heating element is coated with a coating material, and the surface of the coating material is uneven.

In order to achieve the above object, in the fourth invention of the present application, a heat-resistant film is fixed to and supported by a heating element having a resistance heating element provided on a base, and the heat-resistant film is interposed between the heating elements. A pressure member is brought into pressure contact with the film surface and introduced between the heat resistant film and the pressure member as the heat resistant film travels, and the heat energy of the resistance heating element is heated through the heat resistant film. In a heating device for applying to a body, the base of the heating body is uneven.

In order to achieve the above object, in the fifth invention according to the present application, the above-mentioned first, second, third or fourth invention is provided.
The heating device according to the invention is used in a fixing unit for fixing an unfixed toner image formed on a heated body of an image forming apparatus.

In the heating device according to the first aspect of the invention, since the external shape (pattern) of the resistance heating element of the heating element has an angle with respect to the moving direction of the heating target, the heating target heats the heating target. At this time, the direction of the steam due to the thermal expansion of the moisture contained in the heated body is intentionally controlled by the above angle with respect to the upstream of the moving direction of the heated body.

That is, since the vapor is blown out at an angle of the resistance heating element, when the unfixed toner image is formed on the object to be heated, the vapor blowing to the unfixed toner image is reduced. become. As a result, it is possible to prevent the trailing image as compared with the conventional pattern of the resistance heating element which is linear in the longitudinal direction of the substrate.

In the heating device according to the second aspect of the present invention, since the pattern of the resistance heating element of the heating element is discontinuous at an angle with respect to the moving direction of the object to be heated, the pattern is formed on the base of the heating element. The angle of the resistance heating element with respect to the moving direction of the object to be heated can be increased. As a result, as compared with the pattern of the resistance heating element according to the first aspect of the present invention, the amount of vapor blown to the unfixed toner image on the heated object is further reduced, and the trailing image can be further prevented.

In the heating device according to the third aspect of the invention, the surface of the resistance heating element is coated with a coating material,
Since the surface of the coating material has irregularities, the steam when the object to be heated is heated is blown out along the irregularities. As a result, the vapor is dispersed, the amount of air blown to the unfixed toner image on the heated body is reduced, and the trailing image can be prevented.

In the heating device according to the fourth aspect of the present invention, since the base of the heating element has irregularities, the steam follows the irregularities of the base as in the heating device according to the third aspect of the present invention. Since it is dispersed, the trailing image can be prevented.

According to the fifth aspect of the invention, by using each of the heating devices described above in the fixing portion of the image forming apparatus, a good image without a trailing image can be obtained.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) The present invention will be described below based on the illustrated embodiment.

FIG. 1 (b) shows a heating apparatus according to the first embodiment of the present invention, and FIG. 1 (a) shows the structure of the heating body.

The heating element 10 has a ceramic base material 3 as a base. The ceramic substrate 3 has a rectangular shape, and the electrodes 1a and 1b are arranged side by side on one side (left side in the figure).
Is provided. The resistance heating element 2 is formed at an angle on the right side of the electrodes 1a and 1b on the ceramic base material 3 in the figure.

The resistance heating element 2 is formed by mixing a metal such as silver and palladium in a glass paste, printing the mixture on the ceramic base material 3, and firing the mixture at approximately 800 ° C.

The pattern (appearance shape) of the resistance heating element 2 has an X-axis at a certain position in the short side direction of the ceramic base material 3 and a Y-axis at a certain position in the long side direction, and the X-axis is based on the intersection point. It is formed with an angle θ with respect to the axis. As shown in the drawing, it is formed on the ceramic base material 3 with an inclination to the left.

The left end of the resistance heating element 2 which is inclined at this angle θ and the electrode 1b are connected by a conductor 4b, and the right end and the electrode 1a are connected to each other along the long side of the ceramic base material 3 in an external shape. Since they are connected by the conductor 4a, the resistance heating element 2 generates heat by applying a voltage to the electrodes 1a and 1b.

An example of a heating device using such a heating element 10 is shown in FIG. 1 (b).

That is, in this heating device, the heating element 10 is fixedly supported at a predetermined position, the heat-resistant film 5 is provided on the resistance heating element 2 side of the heating element 10, and the surface of the heat-resistant film 5 is pressed. The pressure roller 6 as a member is brought into pressure contact.

The heat-resistant film 5 is movable in the direction of the arrow in the figure, and as the heat-resistant film 5 travels, the heated body 8 on which the unfixed toner image 7 is formed is added to the heat-resistant film 5. Introduced into the nip between the pressure rollers 6,
The thermal energy of the resistance heating element 2 of the heating element 10 is applied to the heated element 8 via the heat resistant film 5 to fix the toner image.

In an electrophotographic printer as an image forming apparatus using such a heating device, when the heated body 8 moves in the width direction of the heated body 10 (direction of arrow Q in FIG. 1A), resistance is increased. Since the resistance heating element 2 forms an angle θ with respect to water vapor and the like generated near the heating element 2, the water vapor will be blown out at an angle with respect to the upstream side in the moving direction of the object to be heated 8 (FIG. 1A). Arrow y1 direction: see arrow P in FIG. 1 (b)).

Therefore, the amount of water vapor blown out toward the unfixed toner image 7 in the upstream direction, which causes a trailing image, is reduced. Therefore, as compared with the conventional pattern of the resistance heating element linear in the longitudinal direction of the ceramic substrate. In this embodiment, the effect of preventing the trailing image can be obtained.

Therefore, the image forming apparatus can obtain a good image with few trailing images.

(Embodiment 2) FIG. 2 shows the structure of a heating element of a heating apparatus according to Embodiment 2 of the present invention.

The heating element 10A has a ceramic base material 3 as a base. The ceramic substrate 3 has a rectangular shape, and the electrodes 1a and 1b are arranged side by side on one side (left side in the figure).
Is provided. Then, on the right side of the electrodes 1a and 1b on the ceramic base material 3 in the figure, the resistance heating element 2A is angled.
Is formed.

The resistance heating element 2A is formed by mixing a metal such as silver and palladium in a glass paste, printing the mixture on the ceramic base material 3, and firing the mixture at about 800.degree.

The pattern (appearance shape) of the resistance heating element 2A has the X axis on the upper side of the center of the ceramic substrate 3 in the short side direction and has a predetermined interval in the long side direction at certain positions in the long side direction. The Y-axis and the Y′-axis are formed at an angle θ with respect to the X-axis with the respective intersections as base points.

That is, in the vicinity of the center of the resistance heating element 2A, a so-called V-shape in which a protrusion is formed in the width direction (arrow Q direction in FIG. 2) upstream of the heating element 10A to which the heating target 8 described later moves. Is formed.

As described above, since the pattern of the resistance heating element 2A is formed into a substantially V shape, the angle of the resistance heating element 2A on the ceramic base material 3 becomes larger than that in the first embodiment.

The left end of the resistance heating element 2 in the drawing is connected to the electrode 1b by the conductor 4b, and the right end of the resistance heating element 2 is extended from the right end to the upper side in the drawing along the short side of the ceramic substrate 3. After that, the resistance heating element 2A generates heat by applying a voltage to the electrode 1a and the electrode 1b because they are connected by the conductor 4a having an external shape along the long side.

Since the heating device using this heating element 10A is the same as the heating device of the first embodiment, the description of its structure and operation will be omitted. still,
In the constituent parts shown below, the same parts as those of the first embodiment are designated by the same reference numerals.

In the electrophotographic printer as an image forming apparatus using the heating device, the heated object 8 is the heating element 10A.
When moving in the width direction (direction of arrow Q in FIG. 2), water vapor or the like generated near the resistance heating element 2A blows out at a certain angle with respect to the Y axis and the Y ′ axis (y1, y1 ′ in FIG. 2).
Direction), the angle θ formed by the resistance heating element 2A with respect to the X axis is larger than that in the first embodiment, and therefore, the unfixed toner image 7 in the upstream direction of the moving direction of the heated object 8 is formed.
However, since the amount of water vapor blown out is further reduced and the generated water vapor moves in a shorter distance in the x-axis direction, the effect of preventing a trailing image can be obtained compared to the first embodiment described above.

Therefore, even in the image forming apparatus, it is possible to obtain a good image as compared with the first embodiment without the trailing image.

(Embodiment 3) FIG. 3 shows the structure of a heating element of a heating apparatus according to Embodiment 3 of the present invention.

The heating element 10B has a ceramic base material 3 as a base. The ceramic substrate 3 has a rectangular shape, and the electrodes 1a and 1b are arranged side by side on one side (left side in the figure).
Is provided. Then, the electrodes 1a and 1b on the ceramic base material 3 are formed on the right side in the drawing with an angle to form a discontinuous resistance heating element 2B.

The resistance heating element 2B is formed by mixing a metal such as silver and palladium in a glass paste, printing it on the ceramic base material 3, and then firing it at about 800.degree.

The pattern (appearance shape) of the resistance heating element 2B is discontinuous in the long side direction of the ceramic base material 3. That is, a certain position in the short side direction of the ceramic base material 3 is defined as the X axis, a certain position in the long side direction is defined as the Y axis, and the intersection point is formed as a base point with an angle θ with respect to the X axis. Are formed in multiple numbers. As shown in the drawing, a plurality of resistance heating elements 2B inclined to the left side are discontinuously formed on the ceramic base material 3.

Of the discontinuous resistance heating element 2B, the left end of the resistance heating element 2B on the leftmost side in the figure and the electrode 1b are connected to the conductor 4.
b, the right end on the rightmost side in the figure and the electrode 1a are connected by a conductor 4a having an external shape along the long side of the ceramic base material 3, and resistance heating adjacent to each resistance heating element 2B is performed. Body 2B
Since the right end and the left end are connected by the conductor 4c, the resistance heating element 2B generates heat by applying a voltage to the electrodes 1a and 1b.

Since the heating device using the heating element 10B is the same as the heating device of the first embodiment, the description of its structure and operation will be omitted. still,
In the constituent parts shown below, the same parts as those of the first embodiment are designated by the same reference numerals.

In the electrophotographic printer as an image forming apparatus using the heating device, the heated object 8 is the heating element 10B.
When moving in the width direction (direction of arrow Q in FIG. 3), the water vapor and the like generated near the resistance heating element 2B blow out at a certain angle with respect to the upstream side of the moving direction of the heated body 8 (see FIG. 3).
In the middle y1 direction), the angle θ formed by the resistance heating element 2B with respect to the X-axis can be made larger by making it discontinuous as compared with the above-described respective embodiments, as will be described later. The amount of water vapor or the like blown out to the upstream unfixed toner image 7 is further reduced, and the effect of preventing the trailing image can be obtained. However, it is economically disadvantageous because the amount of the conductor pattern increases.

Here, regarding the angle θ of the resistance heating element, FIG.
This will be described with reference to FIG.

When the X-axis direction is l and the Y-axis direction is w, the angle θ is given by the following formula 1.

[0055]

## EQU1 ## As θ = tan ⁻¹ w / l 1 is smaller, the angle θ is larger, and the effect is more obtained. Discontinuity is an effective means for reducing l (see FIG. 4B). (Embodiment 4) FIG. 5 shows a heating element of a heating device according to Embodiment 4 of the present invention. The structure is shown.

The heating element 10C has a ceramic base material 3 as a base. The ceramic substrate 3 has a rectangular shape, and the electrodes 1a and 1b are arranged side by side on one side (left side in the figure).
Is provided. Then, a resistance heating element 2C having an angled and reciprocating pattern is formed on the right side of the electrodes 1a and 1b on the ceramic base material 3 in the figure.

The resistance heating element 2C is formed by mixing a metal such as silver and palladium in a glass paste, printing the mixture on the ceramic base material 3, and firing the mixture at about 800.degree.

The pattern (appearance shape) of the resistance heating element 2C is upstream in the width direction (direction of arrow Q in FIG. 5) of the heating element 10A in which the heated object 8 moves near the center in the above-described second embodiment. This is a combination of a so-called substantially V-shaped pattern 2C 'in which a convex is formed in the direction and a reciprocating pattern 2C "along the long side direction of the ceramic base material 3 on the downstream side.

Reciprocating pattern 2C ″ of this resistance heating element 2C
The left end in the figure and the electrode 1b are connected by the conductor 4b, and the left end in the figure of the substantially V-shaped pattern 2C 'and the electrode 1a are connected,
Since the right end of the substantially V-shaped pattern 2C 'and the right end of the reciprocating pattern 2C "are connected by the conductor 4c, by applying a voltage to the electrodes 1a and 1b, the resistance heating element 2
C heats up.

Since the heating device using this heating element 10B is the same as the heating device of the first embodiment, the description of its structure and operation will be omitted. still,
In the constituent parts shown below, the same parts as those of the first embodiment are designated by the same reference numerals.

In the electrophotographic printer as an image forming apparatus using the heating device, the heated object 8 is the heating element 10B.
When moving in the width direction (in the direction of arrow Q in FIG. 4), the effect of preventing the trailing image as shown in the second embodiment is obtained by the substantially V-shaped pattern 2C ′ on the upstream side of the resistance heating element 2C. The reciprocating pattern 2C ″ has the effect of preventing the heater from cracking and increasing the heating area.

(Embodiment 5) FIGS. 6 (a) and 6 (b) show the structure of a heating element of a heating apparatus according to Embodiment 5 of the present invention.

The heating element 10D shown in FIG. 6 (a) is obtained by providing the heating element in the second embodiment with irregularities on its surface. The pattern of the resistance heating element 2A is rounded.

The heating element 10E shown in FIG. 6 (b) is the heating element according to the above-described Embodiment 3 with unevenness.

These irregularities are formed by the surface of the resistance heating elements 2A, 2B coated with a coating material or by the ceramic substrate 3 as a substrate.

Since the heating device using these heating elements 10D and 10E is the same as the heating device of the first embodiment, the description of its configuration and action will be omitted. In addition, in the components shown below, the same components as those of the first embodiment are designated by the same reference numerals.

In the electrophotographic printer as an image forming apparatus using the heating device, the heating target 8 is the heating target 10.
When moving in the width direction of D and 10E (direction of arrow Q in FIG. 6), the generated water vapor and the like blows out along the unevenness, so that the blowout to the unfixed toner image 7 is dispersed, so that the trailing image Effective for prevention.

[0068]

As described above, according to the present invention,
Since the external shape (pattern) of the resistance heating element of the heating element has an angle with respect to the moving direction of the heated object, the thermal expansion of moisture contained in the heated object when the heated object is heated The direction of steam is intentionally controlled by the above angle with respect to the upstream of the moving direction of the object to be heated.

That is, since the steam is blown out at an angle of the resistance heating element, when the unfixed toner image is formed on the heated object, the blowing of the steam to the unfixed toner image is reduced. become. As a result, it is possible to prevent the trailing image as compared with the conventional pattern of the resistance heating element which is linear in the longitudinal direction of the substrate.

According to the second invention, the pattern of the resistance heating element of the heating element has an angle with respect to the moving direction of the object to be heated,
Since they are discontinuous, the angle of the resistance heating element on the base of the heating element can be increased with respect to the moving direction of the heated object. As a result, as compared with the pattern of the resistance heating element according to the first aspect of the present invention, the amount of vapor blown to the unfixed toner image on the heated object is further reduced, and the trailing image can be further prevented.

According to the third invention, the surface of the resistance heating element is coated with the coating material, and the surface of the coating material has irregularities. Therefore, when the object to be heated is heated, the vapor becomes irregular. Will be blown out along.
As a result, the vapor is dispersed, the amount of air blown to the unfixed toner image on the heated body is reduced, and the trailing image can be prevented.

According to the fourth aspect of the invention, since the base of the heating body has irregularities, the vapor is dispersed along the irregularities of the base as in the heating device according to the third aspect of the invention. Therefore, the trailing image can be prevented.

According to the fifth aspect of the invention, by using each of the heating devices described above in the fixing section of the image forming apparatus, a good image without a trailing image can be obtained.

[Brief description of the drawings]

FIG. 1A is a pattern diagram of a heating body of a heating device according to a first embodiment of the present invention, and FIG. 1B is a schematic configuration of a heating device according to an embodiment of the present invention. It is a figure.

FIG. 2 is a pattern diagram of a heating body of a heating device according to a second embodiment of the present invention.

FIG. 3 is a pattern diagram of a heating body of a heating device according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram regarding an angle of a resistance heating element of the heating device according to the embodiment of the present invention.

FIG. 5 is a pattern diagram of a heating body of a heating device according to a fourth embodiment of the present invention.

6 (a) and 6 (b) are unevenness views of the surface of the heating body of the heating device according to the fifth embodiment of the present invention.

FIG. 7 (a) is a pattern diagram of a heating element of a conventional heating device, and FIG. 7 (b) is a schematic configuration diagram of the conventional heating device.

[Explanation of symbols]

1a, 1b Electrode 2, 2A, 2B, 2C Resistance heating element 2C 'Substantially V-shaped pattern 2C "Reciprocating pattern 3 Ceramic substrate (base) 4a, 4b, 4c Conductor 5 Heat resistant film 6 Pressure roller (Pressure) Member) 7 Unfixed toner image 8 Heated object 10, 10A, 10B, 10C, 10D, 10E Heated object y1 Water vapor blowing direction

Claims (5)

[Claims] 1. A heating member, which is fixedly supported and provided with a resistance heating element on a substrate, is pressed against a surface of the heat-resistant film with a pressure member through a heat-resistant film so that the heat-resistant film travels and moves. In a heating device which is introduced between a heat resistant film and the pressure member, and which imparts heat energy of the resistance heating element to a heated object through the heat resistant film, the external shape of the resistance heating element is the heated object. A heating device having an angle with respect to a moving direction of a body. 2. A heating member, which is fixedly supported and provided with a resistance heating element on a substrate, is pressed against a surface of the heat-resistant film with a pressure member through a heat-resistant film, so that the heat-resistant film moves and moves. In a heating device which is introduced between a heat resistant film and the pressure member, and which imparts heat energy of the resistance heating element to a heated object through the heat resistant film, the external shape of the resistance heating element is the heated object. A heating device having an angle with respect to the moving direction of the body and being discontinuous. 3. A heating member, which is fixedly supported and provided with a resistance heating element on a substrate, is pressed against a surface of the heat-resistant film via a heat-resistant film, and a pressing member is pressed against the surface of the heat-resistant film. Introduced between the heat-resistant film and the pressure member, in a heating device for applying the heat energy of the resistance heating element to the object to be heated through the heat-resistant film, the surface of the resistance heating element is a coating material. A heating device which is coated and has an uneven surface. 4. A heating member, which is fixedly supported and provided with a resistance heating element on a substrate, is pressed against a surface of the heat-resistant film through a heat-resistant film, and a pressing member is brought into contact with the heat-resistant film along with the traveling movement of the heat-resistant film. Introduced between the heat-resistant film and the pressure member, in a heating device for applying thermal energy of the resistance heating element to the object to be heated through the heat-resistant film, the base of the heating element has unevenness Characteristic heating device. 5. An image forming apparatus, wherein the heating device according to claim 1, 2, 3 or 4 is used in a fixing unit for fixing an unfixed toner image formed on a heated body.