JPH09237006A - Heating roller, fixing device using it and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a rise time in heating and to obtain desired heat generation with low power consumption. SOLUTION: The heating roller 1 of a thermal fixing device is formed to be provided with recessed and projecting parts 1a and 1b whose diameters are different in an axial direction partially at its ends. The rubber layer 2a of a pressure roller 2 provided with the rubber layer 2a on the outer periphery of a core bar 2b is positioned between the recessed and projecting parts 1a and 1b of the roller 1, and an energizing means 3 applies energizing force in a direction shown by an arrow F to the rubber layer 2a, so that a nip part (n) is formed. Since the roller 1 is provided with the recessed and projecting parts 1a and 1b, the crushing rigidity of the roller 1 is enhanced even though its thickness (t) is made small. Therefore, the heat capacity of the roller 1 is made small by thinning the roller 1 in thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device and a method for manufacturing a heat roller used for the fixing device.
In an electrophotographic recording device such as a copying machine, a fax machine, or an electrophotographic printer, an image made of heat-fusible toner formed on the surface of a recording material such as paper or film is heated to form a permanently fixed image on the surface of the recording material. The present invention relates to a heat generating roller of a heat fixing device for fixing, a fixing device using the heat generating roller, and a method of manufacturing the heat generating roller.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus such as a copying machine or a printer, an electrostatic latent image formed on the outer peripheral surface of a photoconductor is developed with a developer (toner) and the developed toner image is recorded. It adheres (transfers) to paper and fixes and fixes the transferred image. As the fixing device, a heat roller fixing device is generally used, which performs fixing by heating and melting the toner transferred to the recording paper. A typical fixing device based on this heat roller fixing method arranges a pressure roller in pressure contact with a heat roller equipped with a halogen lamp inside, and conveys the transfer paper to the nip portion between the heat roller and the pressure roller. It is configured to melt and fix the developer on the transfer paper at the nip portion between the heat roller and the pressure roller heated by the radiant heat of the halogen lamp.

However, in the fixing device having such a structure, it takes several minutes for the temperature of the heat-generating roller to rise to the temperature required for melting the developer, so that the rising time becomes long. Therefore, in this type of fixing device, in order to realize an improvement in operability of promptly starting recording (copying or printing) after the start of operation, even if the fixing unit is in a standby state when no recording operation is performed, It is necessary to supply power to the halogen lamp of the heating source and keep the heat generating roller at a constant temperature at all times. However,
In the fixing device configured to constantly supply power to the fixing unit as described above, the standby power consumption occupies a large proportion of the total power consumption of the image forming device, which hinders reduction of the power consumption of the image forming device. ing.

In order to solve such a problem, a heating roller having a thin wall thickness of a tubular base pipe made of metal or ceramic, or a heating element pattern is printed or sprayed on the outer surface of the base pipe. Adhered surface heating rollers have been proposed. However, in general, in order to efficiently fix the toner on the transfer paper, in order to obtain a sufficient nip between the heat roller and the pressure roller, the pressure roller must be pressed against the heat roller with a large pressure contact force. I won't. For this reason, in the heat-generating roller whose base is simply thinned by the above-described method, the base pipe is largely deflected when it is pressed, and the mechanical strength of the heat-generating roller is reduced.

As a conventional technique aiming at preventing such bending of the roller, Japanese Patent Laid-Open No. 63-2498 has been proposed.
The "heat fixing device" described in Japanese Patent Laid-Open No. 75-75 is known.
The "fixing device" described in Japanese Patent No. 8810 is disclosed.
Further, a "fixing device" disclosed in Japanese Patent Application Laid-Open No. 4-371984 is disclosed as a structure for increasing the thermal efficiency of heating by a halogen lamp.

In the heat fixing device described in Japanese Patent Laid-Open No. 63-249875, the heating roller is sandwiched between the pressure roller and the at least one anti-deflection roller from above and below to reduce the occurrence of bending of the heating roller. The fixing device is configured to perform.

In the fixing device described in Japanese Patent Laid-Open No. 5-188810, a synthetic resin heat generating pipe is integrally formed on the outer circumference of a metal reinforcing pipe to ensure strength, and pressure is applied to the integrally formed pipe. The fixing device has a structure in which the roller and the roller are in pressure contact with each other.

The fixing device described in Japanese Unexamined Patent Publication No. 4-371984 is a heating system in which a halogen lamp is used as a heat source and the halogen lamp is coaxially installed in a heating roller. A rib is provided on the inner wall surface of the heating roller. This is a fixing device in which the inner wall area is made larger than the outer peripheral area to improve the heat receiving efficiency of the heat generating roller.

[0009]

Problems to be Solved by the Invention JP-A-63-2498
In the configuration of the heat fixing device described in Japanese Patent Publication No. 75, the heat generating roller is sandwiched between the pressure roller and the deflection preventing roller from above and below, and therefore the heat generating roller itself needs to have appropriate strength. If the wall thickness of the base pipe is reduced to reduce its heat capacity, the heat-generating roller itself is destroyed by the pressure between the pressure roller and the anti-deflection roller, making it difficult to support high-speed machines. .

Further, in the fixing device described in Japanese Patent Laid-Open No. 188810/1993, the compression strength is increased by integrally forming the heat generating pipe and the metal reinforcing pipe, but in this configuration, the heat capacity of the heat generating roller itself is small. However, since the heat escapes to the reinforcing pipe, a rapid temperature rise cannot be obtained.

Further, although the structure of the fixing device described in Japanese Patent Application Laid-Open No. 4-371984 is useful for ensuring strength, the ribs increase the heat capacity of the base pipe, so that a rapid temperature rise and strength are achieved. Can't be compatible. As described above, at present, a thermal fixing device having a heating means capable of obtaining a rapid temperature rise and having a strength sufficient for a high speed machine has not been realized.

The present invention has been made in view of the above circumstances, and (1) the rise time is shortened by reducing the occurrence of crushing of the heat generating roller and ensuring the strength without increasing the heat capacity. (2) providing a highly durable device, (2) providing a highly durable device that reduces crushing of the heat roller, reduces the number of parts, reduces cost, and has a short rise time. ) To provide a highly durable device with a short rise time, which reduces the occurrence and collapse of the heat roller.
(4) To provide a device that reduces crushing of the heat generating roller and further reduces the manufacturing process, has a short rise time, and has high durability, and (5) Reinforces to reduce the occurrence of bending of the heat generating roller and crushing. (1) to provide a device having a high durability and a short rise time by reducing the contact portion between the reinforcing portion and the heat generating roller, and (6) preventing the heat generating resistance layer from being damaged during processing, And (7) a method for manufacturing a base pipe of a heating roller capable of easily processing a plurality of concavities and convexities.

[0013]

According to a first aspect of the present invention, there is provided a heating roller used in a fixing device of an electrophotographic recording device,
The heat generating roller has an uneven portion at the end thereof, which has different diameters in the axial direction of the heat generating roller.

According to a second aspect of the present invention, in the heat generating roller according to the first aspect, the maximum diameter of the uneven portion is set larger than the outer diameter of the heat generating roller.

According to a third aspect of the present invention, in the heat-generating roller according to the first or second aspect, the uneven portion also serves as a groove for fixing a thrust stopper of the heat-generating roller.

According to a fourth aspect of the present invention, a heat generating roller having a heat source on its surface is used, and an uneven portion having a different diameter in the axial direction of the heat generating roller is provided at an end of the heat generating roller, and a reinforcing pipe is provided inside the heat generating roller. Is inserted so that the reinforcing pipe and the heat generating roller are in line contact with each other at the uneven portion.

According to a fifth aspect of the present invention, there is an uneven portion having different diameters in the axial direction of the heat roller, and the uneven portion rotatably supports the heat roller on the outer peripheral surface near both ends of the heat roller. It is provided inside the bearing.

According to a sixth aspect of the present invention, when a heat generating roller having a heat source on its surface is manufactured, and a heat generating roller having a shape having uneven portions having different diameters in the axial direction of the heat generating roller is manufactured, the base pipe of the heat generating roller is manufactured. Then, a plurality of irregularities having different diameters in the longitudinal direction are formed on a surface perpendicular to the axis of the base pipe, and then a heating resistor is applied to the surface of the base pipe.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a base pipe for a heat generating roller having a heat source on a surface thereof, wherein the heat generating roller has a concavo-convex portion having different diameters in an axial direction. While rotating about the axis, a pair of rollers are axially symmetrically pressed on the outside of the base pipe at a position corresponding to the unevenness of the processed end portion to process a plurality of unevenness.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a schematic side sectional view for explaining a first embodiment of a heat generating roller according to the present invention, in which 1 is a heat generating roller and 1a and 1b are concave and convex portions. Reference numeral 2 is a pressure roller, 2a is a rubber layer, 2b is a core metal, 3 is an urging means, n is a nip portion, t is the thickness of the heat roller, and F is an urging force. In addition, in the drawings after FIG. 1, the same reference numerals as those in FIG.

The heat fixing type heat generating roller shown in FIG.
A heat generating roller 1 provided with uneven portions 1a and 1b having different diameters in the direction perpendicular to the axis and having uneven longitudinal cross-sections at the ends.
And a pressure roller 2 provided outside the cylinder of the heat roller 1 so as to correspond to the portions excluding the uneven portions 1a and 1b,
Further, urging means 3 for urging at least one of the heat generating roller 1 and the pressure roller 2 by the urging force F shown by an arrow to bring the heat generating roller 1 and the pressure roller 2 into pressure contact with each other.
Is provided. The heat generating roller 1 is rotatably supported at the outer circumferences of both ends, and the pressure roller 2 is rotatably supported at both ends of the core metal 2b so as to be movable in a direction perpendicular to the shaft.

The heat generating roller 1 has a cylindrical shape (hollow shape),
Further, the base pipe is provided with concavo-convex portions 1a and 1b having different diameters in the direction perpendicular to the cylinder axis and having a plurality of concavo-convex cross-sections in the longitudinal direction at both ends. As a heating method of the heating roller 1, there are a halogen lamp method, a surface heating method, and a substrate heating method in which the substrate pipe itself serves as a heating element.

The halogen lamp system has a coaxial halogen lamp (not shown) inside the base material of the heat roller 1, and the heat generated by the halogen lamp causes heat radiation to raise the roller surface temperature. As a material for the base pipe of this system, a material having good thermal conductivity such as Al or SUS is used.

In the surface heating method, the material of the base pipe is
Glass, ceramics, resin, or metals such as Al and SUS are used. On the surface of the base pipe, a ceramic heating element, nichrome, Ta ₂ N, RuO ₂ , Ag / Pd, etc. having a heating resistor formed in a planar or linear shape by thermal spraying, coating, printing, etc., The heating resistor is heated to generate heat. When the above metal is used as the base pipe of the surface heating type heat generating roller 1, it is necessary to provide an insulating layer made of a resin material such as SiO ₂ or polyimide for electrical insulation between the base pipe and the heat generating resistor. .

In the base heating element system in which the base pipe itself is a heating element, examples of the base material include ceramics in which a conductive material is dispersed, and conductive fibers formed in a tubular shape. To be Furthermore, both the halogen lamp method and the surface heating method improve the releasability from the toner, prevent the heating element from being damaged by the contact between other members and the heating element, and use the heating resistor as an electrical resistor. A heat resistant resin layer (not shown) made of Teflon or the like is formed for the purpose of electrical insulation.

The wall thickness of the base pipe of the heat generating roller 1 is smaller in order to shorten the time from the start of heating the heat generating roller 1 to the desired fixing temperature after heating the heat generating roller 1, that is, the so-called temperature rising time. Is good. Especially, PPC, printer, P
The power supply to the fixing device is turned off when the PF is on standby, and the temperature rise time (desirably 30 seconds) to achieve both the energy saving that the user does not wait for the user to start up quickly when reprinting and the convenience of the user In order to achieve the following, more desirably 10 seconds or less,
Although it depends on the material of the base pipe of the heat generation roller, the materials commonly used for heat generation rollers (metals such as Al and SUS,
(Ceramics, glass, heat resistant resin, etc.)
It is necessary to make the wall thickness t 1 mm or less. In the case of such a thin heating roller, the durability against load is naturally weakened, so that the heating roller 1 according to the present invention is particularly effective.

A wide range of the uneven portions 1a and 1b in which the heat roller 1 is provided with a plurality of unevenness has a great effect in preventing crushing, but if it is too wide, the entire length of the heat roller 1 becomes long. However, the size of devices such as PPCs, PPFs, printers, etc., in which they are mounted also becomes large, so it is usually preferable to set it to 30 mm or less. Also, as for the pitch of the concavities and convexities (the distance between the adjacent convex portions), the narrower is more effective, but the pitch must be at least twice the wall thickness of the base pipe, and it should be as small as possible within that range. Is desirable. Further, as the position (distance from the end portion of the heat generating roller) where the concave-convex portions 1a and 1b are formed, it may be formed up to the end portion or may be formed at a certain distance from the end portion.

As a method of processing the uneven portions 1a and 1b, there is a method of forming two semi-cylindrical base materials having the uneven portions by press molding and welding them. In this method, the roller material can be processed with any of metal, glass, and resin. According to this configuration, in FIG. 1, by rotating the heat generating roller 1, the pressure roller 2 is driven to rotate without causing the heat generating roller 1 to bend, so that the heat generating roller 1 and the pressure roller 2 are rotated. Nip between n
By passing the transfer paper (not shown) on which the toner image is formed, it is possible to fix the toner image on the transfer paper without disturbing it. Here, the pressure roller 2 may be driven and the heat roller 1 may be driven to rotate.

The pressure roller 2 is constituted by providing a rubber layer 2a having a good releasability such as silicon rubber on the outer peripheral surface of a cored bar 2b made of a metal roller, and the urging means 3 is a coil spring or a plate. It consists of a pressure mechanism such as a spring, and heat generation roller 1
And the pressure roller 2 in pressure contact with each other in the direction of arrow F. As a result, a nip portion (mutual pressure contact portion) n for conveying and heating the transfer paper is formed between the heat generating roller 1 and the pressure roller 2.

(Embodiment 1) The heat generating roller 1 having the structure described in claim 1 was used as an embodiment 1 and was evaluated by contacting and holding the pressure roller 2 as shown in FIG. . As Comparative Example 1, an evaluation was performed using a heat-generating roller in which the base material pipe is not provided with uneven portions. Heat generating roller structure: Fig. 1 Diameter of heat generating roller 1 = 30 mm Thickness of base material t = 0.5 mm Material of base material = SUS Width of uneven portion = 30 mm Pitch of uneven portion = 2 mm

The load was gradually increased, and Example 1 and Comparative Example 1
As a result of comparing the durability of the heat generating roller 1 with and
It became like.

[0032]

[Table 1]

As is clear from this result, the heat generating roller 1 of Example 1 can withstand a larger load, and the load against the load when it is used by incorporating it into an actual device (PPC, PPF, printer, etc.). It is possible to increase the margin (safety factor). In the case of the first embodiment, when the load in the actual machine is 12 kgf, the safety factor is 10 times or more, and a reliable heat generating roller can be realized.

(Second Embodiment of the Invention) FIG. 2 is a partial cross-sectional view for explaining a second embodiment of a heat generating roller according to the present invention. FIG. 2 (A) shows the dimensions of the heat generating roller. Figure,
FIG. 2B is a diagram showing the position of the bearing, in which D ₁ is the maximum outer diameter of the uneven portion 1 a, D ₂ is the outer diameter of the heat roller 1, and 4 is the bearing.

As shown in FIG. 2A, the maximum diameter D ₁ of the uneven portion 1a of the heat generating roller 1 is made larger than the outer diameter D ₂ of the heat generating roller 1. In addition, as shown in FIG.
The bearing 4 rotatably rotatably supports the heat roller 1 has inner races on the outer circumferences at both ends, and the uneven portions 1a and 1b of the heat roller 1 are provided.
The heat generating roller 1 can also serve as a thrust stopper for stopping the thrust force acting in the axial direction on the convex portion of the end portion of.

(Example 2) As Example 2 of the heat generating roller having the structure described in claim 2, the heat generating roller 1 shown in Fig. 2 is installed as shown in Fig. 2 (b), and a thrust stopper is provided. It was rotated without provision. Configuration of heating roller 1: FIG. 2 (b) Diameter of heating roller 1 D ₂ = 30 mm Thickness of base material t = 0.5 mm Material of base material = SUS Installation width of uneven parts = 30 mm Pitch of uneven parts = 2 mm maximum diameter D ₁ = 40 mm As a result of the parts, the thrust direction f of displacement of the roller also be 1000 rpm was observed.

(Third Embodiment of the Present Invention) FIG. 3 is a partial perspective view for explaining a third embodiment of a heat generating roller according to the present invention, in which 5 is a thrust stopper. .

In the third embodiment of the present invention, the thrust stoppers 5 fixed to the respective end portions of the heat generating roller 1 are formed by using the concave portions of the uneven portions 1a (1b) of the heat generating roller 1 as fixing grooves for the thrust stoppers 5. , Fixed in the recess. Conventionally, the thrust stopper 5 is provided with a thrust stopper fixing hole in the base of the heat roller 1 and is fixed in the thrust stopper fixing hole. However, the uneven portions 1a and 1b of the heat generating element 1 have a role of a reinforcing material. Since it has a function as a stop groove of the thrust stopper 5, the number of processing steps can be reduced.

(Fourth Embodiment of the Present Invention) FIG. 4 is a vertical sectional view for explaining a fourth embodiment of a heat generating roller according to the present invention, in which 6 is a reinforcing pipe and t ₀ is the thickness of the reinforcing pipe.

In the fourth embodiment of the present invention, in the heat generating roller shown in FIG. 1, the thickness t _{0 is} inside the heat generating roller 1.
4 is provided so as to reinforce the heat generating roller 1. The heat roller shown in FIG. 4 is of a heat fixing type and has a heat generating layer (not shown). The cylindrical heat generating roller 1 is provided with uneven portions 1a and 1b having different diameters in the direction perpendicular to the axis and having a plurality of unevenness in the longitudinal cross section. A reinforcing pipe 6 is provided inside the heating roller 1.
Is inserted. The uneven portion 1 is provided on the outside of the heating roller 1 cylinder.
A pressure roller 2 provided between a and 1b so as to face each other in parallel with the axis.
And an urging means 3 for pressing the heating roller 1 and the pressure roller 2 into contact with each other by urging the urging force F indicated by an arrow on at least one of the heating roller 1 and the pressure roller 2 to the other. There is. The heat generating roller 1 and the reinforcing pipe 6 are in line contact with each other at the smallest diameter portion of the uneven portions 1a and 1b.

The heat-generating roller 1 is cylindrical, and the surface of the base material is further provided with concavo-convex portions 1a and 1b having a plurality of concavo-convex longitudinal cross-sections with different diameters in the direction perpendicular to the axis at the end of the base pipe. Ceramic heating element, nichrome, Ta ₂ N, RuO ₂ ,
A heating resistor (not shown) such as Ag / Pd is formed in a planar or linear shape on this base pipe by thermal spraying, coating or printing, and the heating resistor generates heat when energized. Further, on the upper surface of the heating resistor, for the purpose of improving the releasability from the toner, preventing the heating element from being damaged by contact with other members and the heating element, and electrically insulating the heating resistor,
A heat resistant resin layer such as Teflon is formed.

As the material of the base material pipe, glass, ceramics, resin, or metal such as Al or SUS is used. When using a metal, it is necessary to provide an insulating layer (not shown) made of a resin material such as SiO ₂ or polyimide for electrical insulation from the heating resistor. Further, as the heat generating roller 1, other than that, the base material pipe itself may be a heat generating element. Examples of such materials include ceramics in which a conductive material is dispersed, and conductive fibers formed in a tubular shape.

The material of the reinforcing pipe 6 may be ceramics, resin, or metal such as SUS or aluminum (Al). Desirably, a material whose coefficient of thermal expansion is not so different from that of the substrate is preferable. It is more desirable that the heat capacity and the thermal conductivity are small.

According to this structure, in the heat-generating roller shown in FIG. 4, by rotating the heat-generating roller 1, the pressure roller 2 is driven and rotated without causing the heat-generating roller 1 to bend. By passing the transfer paper (not shown) on which the toner image is formed through the nip portion n between the heat roller 1 and the pressure roller 2, the toner image can be fixed on the transfer paper without disturbing it. . here,
The pressure roller 2 may be rotationally driven and the heat roller 1 may be driven to rotate.

The pressure roller 2 is composed of a rubber layer 2a having a good releasability such as silicon rubber provided on a core metal 2b made of a metal roller, and the urging means 3 is a coil spring or a leaf spring. The heat generating roller 1 and the pressure roller 2 are brought into pressure contact with each other by a biasing force F indicated by an arrow generated by the biasing means 3. As a result, a nip portion (mutual pressure contact portion) n for conveying and heating the transfer paper is formed between the heat generating roller 1 and the pressure roller 2.

(Embodiment 3) Using the heat generating roller 1 having the structure shown in FIG. 4, a fixing device as described below was prepared, and the rising time when 800 W of electric power was supplied to the heat generating roller 1 was measured. . As Comparative Example 3, when the uneven portion is not provided on the end portion of the base material (heat generating roller 1 and reinforcing pipe 6
Measurement was also performed. Structure of heating roller: Fig. 4 Diameter D ₂ of heating roller 1 = 30 mm Thickness of base material t = 1 mm Material of base material = Liquid crystal polymer Installation width of uneven portion provided on base material = 30 mm Material of reinforcing pipe = SUS reinforcement Pipe wall thickness t ₀ = 0.5 mm Heat source supply power of heat generating roller: 800 W Width of heating portion of heat generating roller: 305 mm Set temperature of heat generating roller: 180 ° C. As a result, in the case of Example 3, the rise time is It took 12 seconds in Comparative Example 3 while it was 4 seconds, and the rising time of Example was 1/3 faster than that of Comparative Example 3.

(Fifth Embodiment of the Invention) FIG. 5 is a partial sectional view for explaining an embodiment of a fixing device using a heat roller according to the present invention. FIG. 5 (A) shows a bearing. FIG. 5B is a view in which the bearing is provided inside the uneven portion, and FIG. 5B is a view in which the bearing is provided inside the uneven portion.

The fifth embodiment relates to a fixing device using the heat generating roller 1 in which the bearing 4 is provided outside the uneven portion 1a (1b) of the heat generating roller 1, as shown in FIG. 5 (A). The case where the bearing 4 is provided outside the uneven portion 1a (1b) of the heat roller 1 and the uneven portion 1a as shown in FIG.
When the heating roller 1 provided inside (1b) bends in a direction perpendicular to the axis, the amount of deflection is as shown in FIG. (1
When it is provided outside of b), it is smaller and the effect of correcting the deflection is greater.

(Embodiment 4) As Embodiment 4 of the fixing device using the heat-generating roller described in claim 5, the heat-generating roller 1 (concavo-convex portion 1a (1b)) shown in FIG. The amount of deflection was measured when a weight was applied to (inside).
As a comparative example, the uneven portion 1a (1b) shown in FIG. 5 (B)
The heat-generating roller in the case where is outside the bearing 4 was also evaluated. Structure of heat generating roller 1: FIG. 5 Diameter of heat generating roller 1 D ₂ = 30 mm Thickness of base material t = 0.5 mm Material of base material = SUS Installation width D ₁ = 30 mm of uneven portion Pitch of uneven portion = 2 mm

The load was gradually increased to obtain Example 4 and Comparative Example 4.
Table 2 shows the results of comparing the deflections of the heat roller 1 with
It became like.

[0051]

[Table 2]

(Sixth Embodiment of the Present Invention) In the sixth embodiment of the present invention, a heat source is provided in the vicinity of the surface of the heat generating roller 1, and heat is generated with the structure of the heat generating roller described in claim 1. The present invention relates to a manufacturing method of the roller 1, which is a manufacturing method in which the unevenness portions 1a and 1b are first processed in the base pipe and then the heating resistor is applied to the surface of the base pipe in the next step. By taking this step, it is possible to prevent the heating resistor from being damaged during processing.

(Embodiment 5) An embodiment 5 of the method for manufacturing a heat roller according to claim 6 will be described below. An example of a manufacturing process of a surface heating roller having a heat source of a heating resistor on the surface and having the structure of the fixing roller according to claim 1 shown in FIG. 1 will be described. First step: Width 30mm by stamping using liquid crystal polymer
Make two semi-cylinders with irregularities in the range of 1 and weld them to make a cylinder with a thickness of 1.0 mm and a diameter of 30 mm. Second step: the welded portion is polished to smooth the surface to form a substrate. Third step: A heating resistor made of Ag / Pd is applied to the surface of the base pipe. Fourth step: A conductive resin material (trade name: Dotite, manufactured by Fujikura Kasei Co., Ltd.) is applied as an electrode portion of the base pipe. Fifth step: Teflon is applied for the purpose of electrically insulating the heating resistor other than the electrode portion. Through such steps, the heating resistor layer was not damaged during processing.

(Seventh Embodiment of the Present Invention) In the seventh embodiment of the present invention, a heat-generating roller 1 having the structure of the heat-generating roller 1 according to claim 1 having a heat source near the surface is manufactured. The present invention relates to other embodiments.

FIG. 6 is a perspective view for explaining another embodiment of the method for manufacturing a heat roller according to the present invention, in which 7 is a roller.

The heat-generating roller 1 having a heat source on its surface is shown in FIG.
When using the constitution of the heat generating roller 1 having the concave and convex portions 1a and 1b on both sides of claim 1, the concave portion of the concave and convex portion 1a (1b) is rotated while rotating the tubular base pipe as shown in FIG. This is a method of manufacturing a surface heating roller in which a peripheral portion of a pair of rollers 7 is axially pressed at symmetrical positions of a base pipe 1 in a processing portion to be processed to process a plurality of unevenness, and after processing of the unevenness portion 1a (1b) is completed. Then, surface heating and cleaning are performed, and the heating roller 1 is manufactured through the manufacturing steps of the second to fifth steps shown in the sixth embodiment. By selecting the outer peripheral surface shape of the roller 7 according to the shapes of the uneven portions 1a and 1b, it is possible to inexpensively manufacture the uneven portions having a plurality of shapes.

[0057]

The effect corresponding to the invention of claim 1 is a heat-generating roller used in a fixing device of an electrophotographic recording apparatus, wherein the heat-generating roller has unevenness at its end portion, the diameter of which varies in the axial direction of the heat-generating roller. Since the heat generating roller 1 has a thin hollow body, the second moment of area becomes large by providing a plurality of irregularities at the end portions at right angles to the longitudinal direction, so that the entire base body is thickened. Can be reinforced without doing
As a result, the heat capacity of the heat-generating roller 1 is reduced, the temperature rise time can be shortened, preheating during standby is not required, and the total power consumption can be significantly reduced. You can Further, the entire structure can be downsized and the cost can be reduced as compared with the case where the deflection preventing roller is arranged outside the heat generating roller.

Effect corresponding to invention of claim 2: Claim 1
In the fixing device described in (1), since the maximum diameter of the uneven portion is set to be larger than the outer diameter of the heat generating roller, an E ring or the like is used as a thrust stopper in the conventional configuration. Since the plurality of concave and convex portions also serve as thrust stoppers, the number of parts is reduced and the cost is reduced.

Effect corresponding to the invention of claim 3: Claim 1
Alternatively, in the fixing device according to the second aspect, since the uneven portion also serves as a groove for fixing the thrust stopper of the heat roller, in the conventional configuration, a hole is formed in the base of the heat roller 1 for fixing the thrust stopper. However, the drilling process was required, but it is not necessary and the number of processing steps is reduced, resulting in lower cost.

Effect corresponding to the invention of claim 4: A heat generating roller having a heat source on its surface is used, and an uneven portion having different diameters in the axial direction of the heat generating roller is provided at the end of the heat generating roller, and the inside of the heat generating roller is provided. Since the reinforcing pipe is inserted into the heat generating roller so that the reinforcing pipe and the heat generating roller are in line contact with each other in the concave and convex portion, this configuration allows the end of the heat generating roller 1 in the longitudinal direction even if a hollow substrate is used. Since a plurality of uneven portions provided at right angles serve as a reinforcing member and can be reinforced against crushing without thickening the entire substrate, the heat generating roller 1 having a small heat capacity can be used as a heat generating element of the device. Also,
Furthermore, by inserting a reinforcing pipe inside, it will also prevent bending. Further, since the contact portion between the heat generating roller 1 and the reinforcing pipe 6 makes a line contact, the contact portion is reduced, and the heat dissipation rate to the reinforcing pipe at the time of heating the heat generating roller is reduced. As a result, the temperature rise time of the heat generating roller 1 can be shortened, preheating (preheating) during standby is not required, and a fixing device capable of significantly reducing total power consumption can be obtained.

Effect corresponding to the invention of claim 5: The heating roller has an uneven portion having different diameters in the axial direction, and the uneven portion allows the heating roller to rotate on the outer peripheral surface near both ends of the heating roller. Since it is provided inside the bearing that supports the shaft, the effect of correcting the deflection is greater than when the uneven portions 1a and 1b of the heat generating roller 1 are provided outside the bearing 4.

Effect corresponding to the invention of claim 6: When a heat-generating roller having a heat source on its surface and having irregularities with different diameters in the axial direction of the heat-generating roller is manufactured, the heat-generating roller is produced. The base pipe is subjected to processing of a plurality of irregularities having different diameters in the longitudinal direction on the surface perpendicular to the axis of the base pipe, and then the heating resistor is applied to the surface of the base pipe. Without damaging the layers
A heat roller of high quality can be provided.

Effect corresponding to the invention of claim 7: A method of manufacturing a base pipe for a heat-generating roller having a heat-generating roller having a heat source on the surface thereof, wherein the heat-generating roller has irregularities having different diameters in the axial direction. While rotating the base pipe about the axis, a pair of rollers are pressed axially symmetrically outside the base pipe at a position corresponding to the unevenness of the processed end to process the plurality of unevenness, so that the base having a complicated shape Can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view for explaining a first embodiment of a heat generating roller according to the present invention.

FIG. 2 is a partial cross-sectional view for explaining a second embodiment of a heat generating roller according to the present invention.

FIG. 3 is a partial perspective view of a heating roller for explaining a third embodiment of a fixing device using the heating roller according to the present invention.

FIG. 4 is a vertical sectional view for explaining a fourth embodiment of a heat generating roller according to the present invention.

FIG. 5 is a partial cross-sectional view of a heating roller for explaining an embodiment of a fixing device using the heating roller according to the present invention.

FIG. 6 is a perspective view for explaining another embodiment of the method of manufacturing the heat roller according to the present invention.

[Explanation of Codes] 1 ... Heating roller, 1a, 1b ... Concavo-convex portion, 2 ... Pressure roller, 2a ... Rubber layer, 2b ... Core bar, 3 ... Energizing means, 4 ... Bearing, 5 ... Thrust stop, 6 ... Reinforcement pipe, 7 ... roller,
n ... Nip portion, F ... Energizing force, D ₁ ... Maximum outer diameter of uneven portion 1 a, D ₂ ... Outer diameter of heat-generating roller 1, t ₀ ... Wall thickness of reinforcing pipe.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Shinichi Adachi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Kazuto Kishi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh

Claims (7)

[Claims] 1. A heat-generating roller used in a fixing device of an electrophotographic recording apparatus, wherein the heat-generating roller has uneven portions having different diameters in the axial direction of the heat-generating roller at its ends. . 2. The heating roller according to claim 1, wherein the maximum diameter of the uneven portion is larger than the outer diameter of the heating roller. 3. The fixing device according to claim 1, wherein the uneven portion also serves as a groove for fixing a thrust stopper of the heat roller. 4. A heat-generating roller having a heat source on its surface is used,
An uneven portion having different diameters in the axial direction of the heat roller is provided at the end of the heat roller, and a reinforcing pipe is inserted into the heat roller so that the reinforcing pipe and the heat roller are in line contact with each other at the uneven portion. A heat-generating roller characterized in that 5. A heat generating roller has a concavo-convex portion having different diameters in the axial direction, and the concavo-convex portion is provided inside a bearing that rotatably supports the heat generating roller on an outer peripheral surface near both ends of the heat generating roller. A fixing device using a heat generating roller. 6. When manufacturing a heat-generating roller having a heat-generating roller having a heat source on its surface and having uneven portions having different diameters in the axial direction of the heat-generating roller, the base pipe of the heat-generating roller is connected to the base pipe. A method for manufacturing a heat-generating roller, which comprises applying a heat-generating resistor to the surface of the base pipe after processing a plurality of irregularities having different diameters in the longitudinal direction on a surface perpendicular to the axis of the. 7. A method of manufacturing a base pipe for a heat-generating roller, the heat-generating roller having a heat source on the surface thereof, wherein the heat-generating roller has a concavo-convex portion having a different diameter in a longitudinal direction on a surface perpendicular to the axis of the heat-generating roller. A method for manufacturing a heat-generating roller, characterized in that while rotating the pipe about an axis, a pair of rollers are pressed axially symmetrically outside the substrate pipe at a position corresponding to the unevenness of the processed end to process a plurality of unevenness. .