JP2001290387A - Fixing roller and method of manufacturing fixing roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing roller having an effective shortening of a heating time, sufficient rigidity, good passage of an image recording medium, and good adhesion durability with a release layer. provide. SOLUTION: A fixing roller 10 according to the present invention has a first insulating layer 2, a heat generating layer 3, a first insulating layer 3, a heat generating layer 3, and a cylindrical supporting member (core metal) 1 having a groove 12 extending in a longitudinal direction formed on a surface thereof. The second insulating layer body 4 and the release layer body 6 are provided in this order to prevent deformation of the release layer body 6 between the second insulating layer body 4 and the release layer body 6 and to generate heat. Release layer substrate 5 that conducts heat from the mold toward release layer body 6 has a longitudinal end portion at core metal 1.
Are provided in engagement with and joined to a groove 12 extending in the longitudinal direction of the surface of the base.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roller used in an electrophotographic image forming apparatus such as a copying machine, a printer and a facsimile, and a method for manufacturing the fixing roller.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine, a printer or a facsimile uses a fixing unit including a fixing roller and a pressure roller for fixing an image. In this fixing unit, when the recording paper passes between the fixing roller and the pressure roller, heat from the fixing roller melts the toner and fixes an image on the recording paper. In such an image forming apparatus, it is desired to reduce the time for raising the temperature of the surface of the fixing roller.

For this reason, for example, Japanese Patent Application Laid-Open No. 45-81041
As described in JP-A-9-138605, a heating layer is provided on the outer peripheral surface of a cylindrical support member (external surface heating method), or as described in JP-A-9-138605. For example, a heating layer is provided on the inner peripheral surface of the fixing roller (inner surface heating method) to shorten the time required for the fixing roller surface to heat up.

The fixing roller of the external heat generation type has a heating layer on the outer peripheral surface of a cylindrical support member made of a heat-resistant elastic material such as heat-resistant rubber or heat-resistant plastic or ceramic, and further has a heat-resistant rubber on the outer periphery thereof. Since it has the release layer formed by the method described above, it is easy to mount the heat generating layer on the cylindrical support member.

On the other hand, the fixing roller of the inner surface heating method is
Since the heat generating layer is provided inside the cylindrical support member (inner peripheral surface), the outer periphery of the roller can be easily processed, and the durability of the release layer adhered to the inner layer can be easily obtained. Have.

[0006]

However, in the external surface heating method, a part of the heat generated from the heating layer is taken away by the heat conduction to the cylindrical support member, so that the temperature of the roller surface rises. It has the problem of being inhibited. Also,
Since the release layer is formed directly on the outer peripheral surface of the heat-generating layer formed in a planar shape, it becomes difficult to process the outer periphery of the release layer. As a result, the outer diameter of the roller and the inverted crown shape (the shape in which the outer diameter at both ends in the longitudinal direction of the roller is larger than the outer diameter at the center in order to improve the passage of recording paper) are incorrect. As a result, there is also a problem that the passage of the image recording medium through the fixing roller is deteriorated. In addition, the release layer
It is also difficult to obtain the durability of adhesion to the inner layer (in this case, the planar heating layer).

On the other hand, in the internal surface heating method, it is necessary to reduce the heat capacity of the cylindrical support member in order to effectively shorten the time required for the fixing roller surface to rise in temperature. Therefore, the thickness of the cylindrical support member can be reduced, but there is a problem that the mechanical strength of the cylindrical support member is reduced. As the mechanical strength of the cylindrical support member decreases, deformation such as bending and crushing of the fixing roller tends to occur, and it becomes difficult to generate a sufficient nip pressure for securing good fixing performance. . In addition, it is technically difficult to bond an insulating layer or a planar heat generating layer to the inner peripheral surface of the core material, and it is difficult to secure its reliability.

The present invention has been made in view of the above circumstances, and incorporates the advantages of the internal heating system and the advantages of the external heating system. A fixing roller capable of effectively shortening, obtaining good fixing properties and good passing properties of the recording paper, and obtaining good adhesion durability with the release layer body. It is an object of the present invention to provide a fixing roller manufacturing method for manufacturing such a fixing roller by a simple and inexpensive method.

[0009]

According to a first aspect of the present invention, there is provided a fixing roller which heats and presses a toner in cooperation with a pressure roller to deposit the toner on recording paper. A fixing roller for fixing, wherein a first insulating layer, a heat generating layer, a second insulating layer, and a release layer are laminated on the outer periphery of the cylindrical support member in this order; A release layer substrate that prevents deformation of the release layer and conducts heat from the heat generating layer toward the release layer is further laminated between the second insulating layer and the release layer. It is characterized by being provided.

According to the first aspect of the present invention, since the fixing roller has the release layer base under the release layer,
The heat from the heat generating layer body can be effectively conducted to the release layer body, and the time for raising the temperature of the roller surface can be reduced. Since the mechanical strength of the fixing roller can be made high, good fixing properties can be obtained with a sufficient nip pressure, and accurate processing of the outer diameter and inverted crown shape can be performed, so that good recording paper Can be obtained. Good adhesion durability between the release layer substrate and the release layer can also be obtained.

According to a second aspect of the present invention, in the fixing roller, the value of the thermal conductivity of the release layer substrate is not less than the value of the thermal conductivity of the cylindrical support member.

According to the second aspect of the present invention, since heat is more efficiently conducted to the release layer substrate than to the cylindrical support member, it is possible to reduce the time required to raise the temperature of the fixing roller surface. Can be.

According to a third aspect of the present invention, the fixing roller is characterized in that a groove extending in a longitudinal direction from one end to the other end of the cylindrical support member is formed on an outer peripheral surface of the cylindrical support member.

According to the third aspect of the present invention, the contact area between the first insulating layer body adjacent to the heat generating layer body and the cylindrical support member is reduced, so that heat is transferred to the cylindrical support member. It is possible to easily conduct heat to the release layer substrate, so that the time required for the surface of the fixing roller to be heated can be reduced.

According to a fourth aspect of the present invention, in the fixing roller, a spiral groove is formed on the outer peripheral surface of the cylindrical support member so as to extend from one end in the longitudinal direction of the cylindrical support member to the other end while circumferentially traveling around the outer peripheral surface. Is formed.

According to the fourth aspect of the present invention, a spiral groove is formed on the outer peripheral surface of the cylindrical support member, and the first insulating layer body and the cylindrical support member adjacent to each other with the heat generating layer body adjacent thereto. By reducing the contact area, it is difficult to conduct heat to the cylindrical support member, and it is easy to conduct heat to the release layer substrate. Therefore, the time required to raise the temperature of the fixing roller surface can be reduced. Furthermore, if a groove extending in the longitudinal direction and a spiral groove are formed together in a lattice on the outer peripheral surface of the cylindrical support member,
The contact area between the first insulating layer body and the cylindrical support member can be further reduced, and the time for raising the temperature of the fixing roller surface can be further reduced.

According to a fifth aspect of the present invention, in the fixing roller, when the relationship between the rotation direction and the traveling direction of the spiral groove is clockwise wound around the outer peripheral surface of the cylindrical support member, the outer peripheral surface is circumferentially wound. A left-handed spiral groove extending from one end to the other end in the longitudinal direction of the cylindrical support member is formed.

According to the fifth aspect of the present invention, the spiral groove and the spiral groove and the reverse spiral groove are formed in a grid on the outer peripheral surface of the cylindrical support member, thereby generating heat. By reducing the contact area between the first insulating layer body adjacent to the layer body and the cylindrical support member, it is difficult to conduct heat to the cylindrical support member, and it is easy to conduct heat to the release layer body base. Therefore, the time for raising the temperature of the surface of the fixing roller can be reduced.

According to a sixth aspect of the present invention, in the fixing roller, a longitudinal end portion of the release layer body is engaged with and joined to the groove.

According to the sixth aspect of the present invention, the external force in the rotational direction and the longitudinal direction generated when the recording paper passes through the fixing roller is held by the engagement / joining portion in the groove of the release layer substrate. Therefore, slippage occurring at the interface between the layers of the fixing roller can be reduced, and damage to the insulating layer and the heat generating layer can be prevented.

According to a seventh aspect of the present invention, in the manufacturing method, the first insulating layer, the heating layer, and the second insulating layer are wound in this order around the outer peripheral surface of the cylindrical support member, and the second insulating layer is formed. A first step of reducing the diameter of the base material of the release layer base, which prevents deformation of the release layer on the outer periphery thereof and conducts heat from the heat generating layer toward the release layer, to form a laminate; A second step of cutting the outer peripheral surface of the base material of the release layer substrate, and a third step of forming a release layer on the outer peripheral surface of the cut release layer substrate. I do.

According to the seventh aspect of the present invention, since the diameter of the release layer body is reduced by dry processing by spinning, the insulating layer or the heat generating layer already mounted on the cylindrical support member. Can be processed without contaminating it with a processing liquid or the like. Further, since the load generated during processing is relatively low, there is no concern that the object to be processed is broken, and the release layer body can be easily mounted.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a fixing roller according to the present invention,
Embodiments of a method of manufacturing a fixing roller and an image forming apparatus using the fixing roller will be described with reference to the drawings.

[Fixing Roller] FIG. 2 schematically shows a fixing unit in which the fixing roller according to the present invention is used. The fixing unit 11 is roughly constituted by a fixing roller 7, a pressure roller 8, and a spring 10 as a pressing urging means. The fixing unit 11 is used in an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile.

As will be described later, the fixing roller 7 has a release layer on its surface to facilitate separation from the recording paper 9 as an image recording medium, and generates heat for fixing inside. It has a heating layer.

The pressure roller 8 presses and conveys the recording paper 9 in cooperation with the fixing roller 7, and its central axis is substantially parallel to the central axis of the fixing roller 7. They are arranged facing each other. The spring 10 is for generating a predetermined nip pressure on the pressure roller 8 and urges both rollers so that the center axis of the fixing roller 7 and the center axis of the pressure roller 8 are close to each other while being parallel. . Although not shown, an image recording unit that transfers toner to the recording paper 9 along the formed image and records the image is disposed on the upstream side of the conveyance of the fixing unit 11.

When the recording paper 9 is conveyed from the upstream side of the conveyance, the fixing roller 7 and the pressure roller 8 detect this and start rotating in the direction of arrow A in the figure. The recording paper 9 is guided between the fixing roller 7 and the pressure roller 8 by a conveyance guide (not shown), and is nipped by the two rollers. Transported. At that time, the fixing roller 7
And the nip pressure generated by the action of the spring 10 and the pressure roller 9 melts and pressurizes the toner on the recording paper 9 and fixes it on the recording paper 9.

In this fixing step, the spring 10 provides a sufficient nip pressure necessary for fixing, so that the toner on the recording paper 9 is fixed well. Since the fixing roller 7 is processed to have an accurate outer diameter and an inverted crown shape, the recording paper 9 passes through the fixing unit 11 satisfactorily, and does not cause conveyance deviation or meandering. Since the longitudinal end of the release layer substrate 5 of the fixing roller 7 is engaged and joined to the groove formed on the surface of the release layer 6 of the fixing roller 7, the insulating layer and the heat generation are formed as described later. It is possible to prevent the layer body from being damaged.

Since the fixing unit 11 has a short heating time on the surface of the fixing roller 7, the image forming apparatus using the fixing unit 11 is operated in a power save mode (when the fixing unit 7 is not in use, it serves as a heating element of the fixing roller 7). Power consumption is reduced by turning off the heater and when the user uses it, the built-in sensor detects it and turns on the heater of the fixing roller. can do. In addition, the copying operation can be performed efficiently with time.

The layer structure of the fixing roller 7 cut in the longitudinal direction is schematically shown in the partial sectional view of FIG. In this figure, reference numeral 1 denotes a metal core as a cylindrical support member of the fixing roller 7. A first insulating layer 2, a heat generating layer 3, and a second insulating layer 4 are sequentially laminated on the outer peripheral surface of the cored bar 1.

The first and second insulating layers 2 and 4 are formed of a heat-resistant insulating resin material such as a film-like polyimide. The heating layer 3 is made of, for example, a stainless metal foil (heating resistance pattern), and has a layer thickness of 25 μm to 100 μm.

The cored bar 1 is a basic structure of the fixing roller 7 and has a hollow, substantially cylindrical shape and is made of an aluminum alloy. Since the core metal 1 receives most of the nip pressure provided to the fixing roller 7 by the spring 10 and the pressure roller 8, the core metal 1 is made thick enough to secure its mechanical strength.

As shown in FIG. 3, a large number of grooves 12 extending in the longitudinal direction are formed on the surface of the metal core 1. With this configuration, the contact area between the first insulating layer 2 and the core 1 adjacent to the heat generating layer 3 can be reduced. 1 is difficult to conduct. As a result, the heat is efficiently conducted through the second insulating layer 4 in the direction of the later-described release layer substrate 5 and release layer 6, and is efficiently conducted to the surface of the fixing roller 7.

Further, in order to make it difficult for the heat from the heat generating layer body 3 to be conducted to the core metal 1 and to efficiently conduct the heat to the surface of the fixing roller 7, the core metal 1 is more thermally conductive than the release layer substrate 5 described later. Since it is desirable for the core metal 1 to have a low coefficient, iron, a stainless steel alloy or the like having a lower thermal conductivity may be used for the cored bar 1.

On the outer periphery of the second insulating layer body 4, a release layer body 5 and a release layer body 6 are sequentially laminated. The purpose of the release layer substrate 5 is to efficiently conduct heat from the heat generating layer 3 to the release layer 6 which is the surface (outermost layer) of the fixing roller 7, and to ensure the durability of the adhesion to the release layer 6. It is formed of an aluminum alloy for the purpose of ensuring the mechanical strength and for the purpose of ensuring the mechanical strength as a support when the surface of the release layer body 6 is processed. The thickness of the release layer body 5 is determined by the adhesion to the release layer body 6 and the inadvertent deformation of the release layer body 6 when the outer diameter of the release layer body 6 is processed. As long as the mechanical strength of the release layer 6 is not impaired, a thinner wall is preferable from the viewpoint of efficient heat conduction to the release layer 6.

The release layer body 6 is provided on the outermost layer of the fixing roller 7 in order to facilitate separation from the recording paper 9, but its description is omitted because it is known.

FIG. 4 shows a longitudinal end 1 of the release layer body 5.
3 is a metal core 1 at the longitudinal end of the fixing roller 7.
Engages in a longitudinally extending groove 11 formed on the surface of
It is a fragmentary sectional view showing signs that it was joined. According to this configuration, the first insulating layer 2, the heat generating layer 3, and the second insulating layer 4, which are formed to be shorter in the longitudinal direction than the release layer substrate 5, are combined with the release layer Since the longitudinal end 13 of the base body 5 reaches the surface of the metal core 1 so as to wrap over and engages and is joined so as to bite into the longitudinal groove 11 formed on the surface of the metal core 1, A relative displacement between the gold 1 and the release layer substrate 5 in the rotational direction can be prevented. Thereby, it is possible to prevent slippage at the interface between the layers due to torque in the rotation direction due to friction or the like, which is generated when the recording paper 9 passes,
Breakage of the first and second insulating layers 2 and 4 and the heat generating layer 3 can be prevented.

In this embodiment, the material of the release layer substrate 5 of the fixing roller 7 has been described as an aluminum alloy. However, it is needless to say that the thermal conductivity is higher than that of the aluminum alloy and the release layer body 6 is in close contact with the aluminum layer. Other materials can be used as long as they can secure the mechanical strength while maintaining the properties.

In the present embodiment, the groove formed on the surface of the cored bar 1 has been described as the groove 12 extending in the longitudinal direction.
The spiral groove 14 may be formed as shown in FIG. 5 in consideration of the easiness of the processing, the temperature rise characteristics of the roller, and the like.

As shown in FIG. 6, a groove 1 extending in the longitudinal direction
2 and a spiral groove 14, as shown in FIG. 7, a spiral groove 14, and a spiral groove 15 in which the relationship between the spiral groove 14 and the rotation direction and the traveling direction is opposite. Are formed, the respective grooves intersect in a lattice pattern, and projections 19 and 19 'are formed at the intersections of the grooves. Since the first insulating image body 2 and the metal core 1 adjacent to the heat generating layer body 3 make contact only at the projections 19 and 19 ', the contact area is further reduced.

Although not shown, by forming the longitudinal groove 11, the spiral groove 14, and the spiral groove 15 together,
The contact area between the first insulating layer 2 adjacent to the heat generating layer 3 and the core 1 can be further reduced.

In this case, at the longitudinal end of the core bar 1, the longitudinal end of the release layer substrate 5 is formed with the longitudinal groove 11, the spiral groove 14 and the spiral groove formed on the surface of the core bar 1. By engaging and joining the grooves 15 in the shape of a circle, both the rotational direction and the longitudinal direction of the release layer body 5 can be prevented from slipping.

[Method of Manufacturing Fixing Roller] FIG. 8 is a diagram schematically illustrating the main part of the diameter reducing step of the release layer substrate 5 in the first step of the method of manufacturing the fixing roller according to the present invention. FIG.

On the outer peripheral surface of the cored bar 1, a first insulating layer 2
The heating layer 3 and the second insulating layer 4 are wound.
A mandrel jig 16 having an outer diameter substantially equal to the inner diameter of the hollow portion of the core 1 is inserted into the inner center of the core 1, and a hollow formed of an aluminum alloy is formed on the outer periphery of the second insulating layer 4. The cylindrical base material 5 'of the release layer body is covered and set on a processing machine (lathe) (not shown).

The inner diameter of the base material 5 ′ of the release layer substrate is slightly larger than the outer diameter of the wound second insulating image 4, and the first insulating layer 2 and the heat generating layer 3 are formed. Can be easily put on the core metal 1 around which the second insulating layer body 4 is wound. At the longitudinal end portion, the groove 12 engages with the longitudinally extending groove 12 formed on the surface of the core metal 1. Therefore, slippage in the direction of rotation relative to the metal core 1 does not occur even during processing.

The set mandrel 1 is rotated by a lathe, and a back-up for preventing the object to be worked from being deformed at the time of working from outside the base material 5 ′ of the release layer substrate covered on the mandrel 1. The roller 17 is urged. A spinning roller 18 which is a processing jig for drawing from a position facing the backup roller 17, that is, a position which is the same position in the longitudinal direction of the core bar 1 and a position opposite to the diameter direction of the core bar 1.
With a predetermined contact force. As a result, at the longitudinal position where the spinning roller 18 is in contact, the base material 5 ′ of the release layer substrate is reduced in diameter over the entire circumference, and at that portion, the base material 5 ′ of the release layer substrate is It adheres closely to the second insulating layer body 4.

By moving the backup roller 17 and the spinning roller 18 at a predetermined speed in the longitudinal direction of the cored bar 1 while maintaining their relative positional relationship, the diameter of the base material 5 'of the release layer body is reduced. The process can be advanced in the longitudinal direction, and finally, the base material 5 ′ of the release layer substrate can be brought into close contact with the second insulating layer 4 over the entire length.

[0048]

According to the present invention, since the fixing roller has the release layer base under the release layer, heat from the heat generating layer is effectively conducted to the release layer. The heating time of the roller surface can be shortened. Since the mechanical strength of the fixing roller can be made high, good fixing properties can be obtained with a sufficient nip pressure, and accurate processing of the outer diameter and inverted crown shape can be performed, so that good recording paper Can be obtained. Good adhesion durability between the release layer substrate and the release layer can also be obtained. This makes it possible to provide a fixing roller that can take advantage of the advantages of the internal heat generation method and the advantages of the external heat generation method, and can further solve the problems of both methods.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view schematically illustrating a layer configuration of an example of a fixing roller according to an embodiment of the present invention, which is cut in a longitudinal direction.

FIG. 2 is a perspective view schematically showing a fixing unit in which the fixing roller according to the embodiment of the present invention is used.

FIGS. 3A and 3B are a front sectional view and a partial side view showing a longitudinally extending groove formed on a surface of the fixing roller according to the exemplary embodiment of the present invention. FIGS.

FIG. 4 is a partial cross-sectional view in a longitudinal direction showing a longitudinal end portion of a release layer body joined and engaged with a groove on a surface of a fixing roller according to the exemplary embodiment of the present invention.

FIG. 5 is a partial side view showing a spiral groove formed on the surface of the fixing roller according to the exemplary embodiment of the present invention.

FIG. 6 is a partial side view showing a longitudinally extending groove and a spiral groove formed in a lattice on the surface of the fixing roller according to the embodiment of the present invention.

FIG. 7 is a partial side view showing a spiral groove formed in a lattice shape on the surface of the fixing roller according to the embodiment of the present invention and a spiral groove having a relationship between the rotation direction and the traveling direction opposite to the spiral direction. FIG.

FIG. 8 is an explanatory view schematically illustrating a main part of a diameter reducing step in the first step of the manufacturing method according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylindrical support member (core metal) 2 ... 1st insulating layer body 3 ... Heat generation layer body 4 ... 2nd insulating layer body 5 ... Release layer body base 5 '... Base material of release layer body 6 ... release layer body 7 ... fixing roller 8 ... pressure roller 9 ... recording paper (image recording medium) 10 ... spring (elastic member) 11 ... fixing unit 12 ... groove extending in the longitudinal direction 13 ... length of release layer body base Direction end 14 ... spiral groove 15 ... spiral groove 16 ... mandrel jig 17 ... backup roller 18 ... spinning roller 19, 19 '... projection

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H033 AA02 AA25 AA31 BB14 BB15 BB19 BB21 BB26 3J103 AA02 AA15 AA64 AA65 AA66 BA05 EA01 FA15 GA57 GA58 GA60 3K058 AA02 AA22 BA18 CE13 CE19 DA04 DA26 GA06

Claims (7)

[Claims] 1. A fixing roller for heating and pressing toner in cooperation with a pressure roller to fix the toner on recording paper, wherein a first insulating layer body and a heat generating layer are provided around the outer periphery of a cylindrical support member. A body, a second insulating layer, and a release layer are provided in this order in a stacked manner, and a deformation of the release layer is provided between the second insulating layer and the release layer. And a release layer substrate that conducts heat from the heat generating layer body toward the release layer body. 2. The fixing roller according to claim 1, wherein the value of the thermal conductivity of the release layer body is not less than the value of the thermal conductivity of the cylindrical support member. 3. The cylindrical support member according to claim 1, wherein a groove extending in a longitudinal direction from one end to the other end of the cylindrical support member is formed on an outer peripheral surface of the cylindrical support member. 3. The fixing roller according to 1. 4. A helical groove is formed on the outer peripheral surface of the cylindrical support member and extends from one end to the other end in the longitudinal direction of the cylindrical support member while circling the outer peripheral surface in the circumferential direction. The fixing roller according to claim 1, wherein: 5. When the relationship between the rotation direction and the advancing direction of the spiral groove is right-handed on the outer peripheral surface of the cylindrical support member, the cylindrical support member goes around the outer peripheral surface in the circumferential direction. The fixing roller according to claim 4, wherein a left-handed spiral groove extending from one end in the longitudinal direction of the member to the other end is formed. 6. A longitudinally end portion of the release layer body substrate is engaged with and joined to the groove.
The fixing roller according to any one of claims 1 to 5, wherein 7. A first insulating layer, a heat generating layer, and a second insulating layer are wound in this order around an outer peripheral surface of a cylindrical support member, and a release layer is wound around the outer periphery of the second insulating layer. A first step of reducing the diameter of a base material of a release layer substrate that conducts heat from the heat generating layer body toward the release layer body while reducing the diameter of the base material to form a laminate; Fixing comprising: a second step of cutting the outer peripheral surface of the base material of the body substrate; and a third step of forming the release layer body on the cut outer peripheral surface of the release layer body substrate. Roller manufacturing method.