JPH10228201A - Production of fixing roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the time for warm-up in a fixing device by disposing a cylindrical core metal in a metal cylinder body and adding external force on the outer surface of the cylinder body for plastic processing to decrease the thickness of the cylinder body. SOLUTION: When a core bar of a fixing roll in a fixing device is produced, a cylindrical core metal 52 is disposed in a metal cylinder 51, and external force 53 is added on the outer surface of the cylinder 51 for plastic processing so as to decrease the thickness of the cylinder 51 and to make the cylinder thin. Namely, the metal cylinder 51 such as a raw tube having specified thickness is prepared, on which external force 53 is added by using a die to cause plastic deformation of the tube and to make the tube thin. Thereby, work hardening is induced in the tube by the plastic deformation, and as a result, the tensile strength of the material of the raw tube increases. Therefore, the elastic limit of the cylinder 51 increases, which prevents plastic deformation or changes in the shape in the succeeding production processes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device using a thin cylinder as a core of a fixing roll, a cylinder used for the fixing device, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a copying machine using an electrophotographic process, it is necessary to fix an unfixed toner image formed on a recording sheet into a permanent image.
Conventionally, a heat fixing method of melting a toner by heating and fusing the toner on a recording sheet has been widely adopted.

FIG. 1 is a diagram showing a schematic configuration of a fixing device using a heat fixing method. As shown in FIG. 1, the fixing device includes a heater 31 inside a cylindrical cored bar 32, and a fixing roller 30 having a release layer 33 formed of a heat-resistant resin coating layer or a heat-resistant rubber coating layer on the outer peripheral surface thereof. And a pressure roller 40 that is disposed in pressure contact with the fixing roller 30 and has a heat-resistant elastic layer 42 formed on the outer peripheral surface of a cylindrical cored bar 41. In the fixing process of the unfixed toner image, the sheet 43 on which the unfixed toner image 44 is formed is inserted between the fixing roller 30 and the pressure roller 40 to fix the toner additive by thermal melting.

The heat fixing roller system, in which fixing is performed by a heating roller, has a higher thermal efficiency than the hot air fixing system and the oven fixing system of other heat fixing methods, and therefore has low power (energy saving) and high speed. It is currently most widely used because of its excellent properties and low risk of flames caused by paper jams.

In a fixing device of a heat fixing roller type,
It is desired to shorten the time required for raising the surface temperature of the fixing roll from room temperature to a predetermined set temperature (hereinafter referred to as a warm-up time), but usually requires a long time of 1 to 10 minutes. . Since the warm-up time is simply determined by the relationship between the heat capacity of the roll and the input power, one of the methods to shorten the warm-up time is as follows.
An attempt is made to reduce the roll heat capacity. However, the roll heat capacity has a limit of reduction more than the roll rigidity.

Further, in order to obtain a specified fixing performance, the pressure in the nip portion of the roll pair of the heating roller and the pressing roller is generally required to be about 0.5 to 5.0 kg / cm. . If the pressure is lower than this, the gap due to the presence of irregularities on the paper or roll surface cannot be filled, and heat cannot be efficiently transmitted to the powder toner. For this reason, the toner surface after fixing becomes mottled, and the image quality deteriorates.

Since the total load applied between the two rolls to obtain the pressure required for fixing reaches 20 to 200 kg, the roll (cylindrical body) used as the heating roller has a roll stiffness enough to withstand this load. There is a natural limitation in reducing the roll diameter and making it thinner.

In order to accurately finish the outer shape of a roll used as a fixing roll of a fixing device to a predetermined outer diameter, usually, a metal tube is used, and the metal tube is cut or centerless. Perform grinding. In the case of mass-produced metal pipes, if the pipes are made thin from the beginning, dents, crushes, dents, etc. occur in the pipes, which makes handling difficult. For this reason, it is not possible to reduce the thickness so much. As a result, cutting or centerless grinding for thinning is required.

If the thickness of the roll is too thin, the precision of the shape such as run-out is deteriorated when centerless grinding is performed, and such thinning is very difficult.

Further, for example, in a fixing roll used in a black-and-white copying machine, an offset prevention layer may be electrostatically coated on the outer peripheral surface of the roll. In this case, the adhesiveness of the offset prevention layer to the fixing roll is improved. In order to perform this, a blast process of projecting metal particles on the surface is performed. Even in such a blasting process, if the roll is in a thin state, the strength of the roll is insufficient, so that the roll is dent or the like, and the roll is deformed, thereby deteriorating the shape accuracy. Therefore, in order to ensure the shape accuracy, it is necessary to take measures such as lowering the pressure of the blasting process, and it takes a long time for the blasting process, or the roughening is insufficient, so that the offset prevention layer is peeled off. Problems occur.

On the other hand, conventionally, various roll reinforcing techniques have been developed in order to reduce the stress acting on the roll. In addition, techniques for increasing the allowable stress of the roll have been developed. Next, a technique for reducing the acting stress or a technique for increasing the allowable stress, and the problems when applying them to the fixing device will be discussed.

As a first method, for example, Japanese Utility Model Application Laid-open No.
No. 128665, Japanese Utility Model Publication No. 61-4926, Japanese Patent Application Laid-Open No. 61-59381, Japanese Patent Application Laid-Open No. Hei 6-130845.
In some rolls, a reinforcing member for preventing dents is provided in the roll to increase the strength of the roll without increasing the heat capacity of the roll itself, as described in Japanese Patent Application Laid-Open Publication No. H10-163,086. FIG. 2 is a cross-sectional view illustrating a first example of the structure of a conventional fixing roller. In FIG. 2, 1 is an inner frame of a roll support member, 2 is a support rod supporting the inner frame, 3 is a roll (sleeve), 4 is a thermal insulator, 5 is a coil heater as a heating source,
Reference numeral 6 denotes an offset prevention layer as a release layer, and reference numeral 7 denotes a support shaft.

The fixing roller having the structure shown in FIG. 2 requires a support rod 2 for supporting an inner frame 1 of a reinforcing member for a roll 3 constituting the fixing roller, and requires a very large member having an internal reinforcing structure. For this reason, an increase in the size and cost of the apparatus is inevitable. In addition, when a large member is placed in the fixing roll, the heat capacity of the entire fixing roll is expected to increase, which is not preferable from the viewpoint of reducing the warm-up time. In addition, since the contact portion between the inner frame 1 and the roll 3 must be formed of a thermal insulator 4 such as a resin, a material having a smaller coefficient of thermal expansion as compared with metal is actually a fixing roll. There is a possibility that a problem that the inner frame 1 may fall off during heating may occur.

FIG. 3 is a sectional view for explaining a second example of the structure of the conventional fixing roller. As a second method, as shown in FIG. 3, there is a method in which the thickness of the roll 8 is partially increased in the axial direction to provide a thick portion 9. Also, in this case,
As a modified example, there is a configuration in which a rib for reinforcement is provided in place of the thick portion 9 which partially increases the thickness in the axial direction. A specific example of the second method is described in, for example, Jpn.
949, JP-A-57-155571, JP-A-58-1996060 and the like can be referred to.

In the fixing roller having the structure as in the second method, it is necessary to perform uneven thickness processing in the axial direction inside the cylindrical structure. However, the thickness of the uneven thickness portion is required to be so large. And the thickness becomes approximately equal to the thickness before the uneven thickness processing. In other words, it is very difficult to make the thickness-increased portion a large thickness portion by the thickness-deformation processing in the normal roll manufacturing method. In addition, in order to increase the thickness of the roll, it is necessary to apply the thickness of the roll having a large thickness to the roll by cutting. After that, the outer peripheral surface of the roll is sharply cut to obtain a predetermined thickness. It is necessary and uneconomical.

As a third method, as a method for increasing the allowable stress of a material, a heat treatment involving transformation such as induction hardening or carburizing is known. Such heat treatment actually increases the strength, but the material undergoes a transformation, which causes the roll to be warped or bent and cannot be used as a fixing roll.

[0017]

However, in the method for reducing the acting stress accompanying the structural change as described in the first and second methods described above, the cross-sectional shape in the roll axis direction is reduced. Are discontinuous, and the second moment of area is also discontinuous, so that stress concentration occurs at discontinuous positions in the cross-sectional shape. Therefore, the fracture occurs closer to the reinforcing portion than to the reinforced portion, and the fatigue strength of the roll does not increase so much. Further, since the number of parts such as reinforcing members increases, cost increase is unavoidable and assemblability is poor.

In the heat treatment accompanied by the transformation described as the third method, shape deterioration such as warpage or warping occurs,
In order to prevent this, there is a limit in thinning the raw tube itself before heat treatment, and it is necessary to sharply grind the outer peripheral surface of the roll to obtain a so-called predetermined thinned wall thickness, which is uneconomical. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a first object of the present invention is to provide a fixing device capable of greatly reducing a warm-up time in a fixing device. It is to provide a manufacturing method of. A second object of the present invention is to provide a method for manufacturing a fixing roll, which can improve the productivity of the fixing roll and reduce costs.

[0020]

Means for Solving the Problems In order to achieve the above object, a method of manufacturing a fixing roll according to the present invention has, as a first feature, a method of manufacturing a cylindrical body used as a core metal of a fixing roll. Then, a cylindrical core is disposed inside a metal cylindrical body, and the thickness is reduced by plastic working in which an external force is applied from the outer periphery of the cylindrical body.

Also, as a second feature, the method of manufacturing a fixing roll according to the present invention is a method of manufacturing a cylindrical body used as a core of a fixing roll, wherein a cylindrical core is provided outside a metal cylindrical body. Are arranged, and the thickness is reduced by plastic working in which an external force is applied from the inner periphery of the cylindrical body.

As a third feature, the method of manufacturing a fixing roll according to the present invention is a method of manufacturing a cylindrical body used as a core of a fixing roll, wherein a cylindrical core is provided inside a metal cylindrical body. Is disposed, and the thickness of the cylindrical body is reduced by plastic working by applying an external force from the outer periphery of the cylindrical body, and thereafter, an expanding step of expanding the inner diameter of the cylindrical body is performed to separate the cylindrical body from the core metal. .

As a fourth feature, the method of manufacturing a fixing roll according to the present invention is a method of manufacturing a cylindrical body used as a core of a fixing roll, wherein the cylindrical core is provided outside a metal cylindrical body. Is disposed, the thickness of the cylindrical body is reduced by plastic working to apply an external force from the inner periphery of the cylindrical body, and thereafter, a narrow tube step of narrowing the outer diameter of the cylindrical body is performed to separate from the core metal. And

As a fifth feature, the method of manufacturing a fixing roll according to the present invention is a method of manufacturing a cylindrical body used as a core of a fixing roll, wherein a cylindrical core is provided inside a metal cylindrical body. Is disposed, the thickness of the cylindrical body is reduced by plastic working by applying an external force from the outer circumference of the cylindrical body, and then, in the expanding step of expanding the inner diameter of the cylindrical body, the outer circumference of the cylindrical body is formed into an inverted crown shape to form the core metal. It is characterized by being further apart.

As a sixth characteristic, the method of manufacturing a fixing roll according to the present invention is a method of manufacturing a cylindrical body used as a core of a fixing roll, wherein a cylindrical core is provided outside a metal cylindrical body. In the narrow tube step of reducing the thickness of the cylindrical body by forming the outer circumference of the cylindrical body into an inverted crown shape by plastic working by applying an external force from the outer circumference of the cylindrical body, and then narrowing the inner diameter of the cylindrical body, It is characterized by being further apart.

According to a seventh feature, the fixing device according to the present invention is configured such that a transfer material carrying an unfixed toner image in a pressing area formed by a pressing member pressed against a fixing roll having both ends pivotally supported. In a fixing device that passes and heat-fixes, using a core metal of the fixing roll as described above as a fixing roll,
A mechanism for correcting non-uniformity of a pressurized region caused by elastic deformation of the fixing roll in the axial direction when a load is applied is added to the pressurizing body.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG.
FIG. 3 is a diagram illustrating a process of manufacturing a core metal of a fixing roll of a fixing device. 4, reference numeral 11 denotes a raw pipe, 12 denotes an outer diameter processing, 13 denotes a blast processing, and 14 denotes an offset prevention layer coating processing. FIG. 5 is a diagram illustrating a swaging method according to the method of manufacturing a fixing roll according to the present invention, and FIG. 6 is a diagram illustrating a bulging method according to the method of manufacturing a fixing roll according to the present invention.

When a fixing roll used for a fixing device is manufactured, for example, a thin steel pipe made of iron is used as a core metal of the fixing roll, and in the manufacturing process, as shown in FIG.
1, outer diameter processing 12 is performed, then blast processing 13 is performed, and offset prevention layer coating processing 14 is performed.
Is performed, and the processing for manufacturing the fixing roll is advanced. In such a process, in the outer diameter processing 12 and the blasting 13, a force is applied to the roll of the thin steel pipe for processing from the outside. Therefore, if the roll is thin, the shape is deteriorated due to insufficient roll strength. And other problems occur.

For this reason, in the present invention, when manufacturing the core metal of the fixing roll of the fixing device, as shown in FIG.
A cylindrical metal core (52) inside a metal cylindrical body (51)
Are arranged, and the thickness is reduced and thinned by plastic working in which an external force (53) is applied from the outer periphery of the cylindrical body (51). That is, the metal cylindrical body (51) is, for example, formed into a base tube having a predetermined thickness.
External force is applied, and plastic deformation causes thinning. As a result, work hardening occurs in the raw tube due to plastic deformation, and as a result, the tensile strength of the material in the raw tube increases.

As a result, the elastic limit of the cylindrical body (51) is increased, and plastic deformation and shape change can be prevented even in the subsequent manufacturing process. For this reason, it is possible to prevent a change in shape in the outer diameter processing 12 and the blast processing 13 in the manufacturing process as described above. At the same time, the fatigue limit of the fixing roll naturally increases. Thereby, the thin steel pipe is thinned so that it can be used as a core metal of the fixing roll, and its rigidity is increased.

To explain with a specific example, FIG.
51 is a metal roll to be thinned, 52 is an inner die for swaging, and 53 is a dice for swaging. As described above, the swaging process is performed by the swaging die 53 by disposing the inner die 52 for swaging a cylindrical metal core inside the metal roll 51 which is a metal cylindrical body and is reduced in thickness. Thereby, the metal roll 51
Is plastically deformed by an external force applied from its outer periphery, and its thickness is reduced and its thickness is reduced.

In the swaging shown in FIG. 5, since the inner die 52 for swaging is disposed inside the metal roll 51, the metal roll 51 of the raw tube is degraded in shape such as bending, warping, and ellipse. Never do. For this reason, the outer diameter of the raw pipe can be processed to an outer diameter within a predetermined dimensional tolerance, and the raw pipe is thinned. As described above, since the outer diameter of the thin-walled steel tube can be processed to an outer diameter within a predetermined dimensional tolerance, the outer diameter processing 12 in the manufacturing process can be omitted.

In the swaging as shown in FIG. 5, the degree of thickness reduction (called the degree of processing) is expressed by a ratio obtained by dividing the cross-sectional area of the raw pipe after processing by the cross-sectional area of the raw pipe before processing. If the degree of processing here is, for example, about 40%, the length of the raw tube before processing may be about 70% of the finally required core metal roll length, Material cost can be significantly reduced as compared with the case of processing by removal such as cutting or grinding.

In this case, after the swaging, bulging is performed to increase the inner diameter of the thin-walled tube, and the thin-walled tube is extracted from the inner die for swaging. In this case, the inner die for swaging described above (52) 5) is used as an inner mold for bulging after swaging to increase the inner diameter of the thin-walled tube, thereby preventing shape deterioration when the thin-walled tube is removed from the inner mold after swaging. it can.

FIG. 6 is a view for explaining a bulging method in the method of manufacturing a fixing roll according to the present invention. As shown in FIG. 6, the thin-walled general-purpose roll 61 thinned by swaging is further mounted between an inner mold 62 for bulging and an outer mold 64 for bulging, and a hydraulic pressure is applied thereto. It is spread and thinned.

FIG. 7 is a diagram for explaining another bulging method in the method of manufacturing a fixing roll according to the present invention. In the fixing device of the heating roll type, in order to prevent paper wrinkles at the time of fixing, the core metal of the fixing roll has a structure in which an inverted crown-shaped taper is provided on the outer peripheral surface. Such a process of forming the outer peripheral surface into a tapered shape of an inverted crown is usually performed by centerless grinding. However, in the case of a thin metal roll, there is a problem of shape deterioration similar to that of centerless grinding in the case of thinning. .

In addition, since the inner diameter of the base tube is usually constant, a step is formed on the outer peripheral surface, and the center portion of the roll becomes thinner than the end portion. Therefore, when used as a fixing roll, the strength at the center is reduced.
As a result, the life of the fixing roll is determined by the strength of the central portion. For this reason, the thin part in the center part restricts the strength, and it is difficult to reduce the thickness.

On the other hand, as shown in FIG. 7, the inner peripheral surface of the outer mold 75 for bulging is formed to have an inverted crown-shaped taper, and the outer mold 75 for bulging is used for swaging. By using in combination with the inner mold 72 for bulge processing for expanding the inner diameter of the thin-walled tube later, the taper of the outer peripheral surface can be given simultaneously with taking out the tube after swaging. When such a process is performed, the central portion has no thin portion, so that the strength of the entire roll is significantly increased as compared with the roll in which the central portion is thinner than the end portion.

That is, in the bulging process in this case, as shown in FIG. 7, the thin metal roll 71 of the thin-walled tube thinned by the swaging process is attached to the inner mold 72 for the bulging process.
And into the mold formed by the tapered outer mold 75 for bulge processing, applying a predetermined liquid pressure, and expanding the inner diameter, and at the same time, the outer peripheral surface of the thin metal roll 71 is formed into a tapered shape of an inverted crown. The processing to do.

FIG. 8 is a view for explaining an extrusion method according to another embodiment of the method for manufacturing a fixing roll according to the present invention, and FIG. 9 is a diagram showing still another embodiment of the method for manufacturing a fixing roll according to the present invention. FIG. 4 is a view for explaining an ironing method according to the first embodiment. The plastic deformation of the core metal of the fixing roll according to the present invention is shown in FIG.
As shown in (1), it can also be performed by an extrusion process in which an external force is applied from the inner diameter side of the raw tube to perform plastic deformation. FIG.
In the figure, 81 is a thin metal roll, 82 is a die for extrusion, and 86 is an outer die for extrusion.

In order to obtain good fixing performance, the process of forming the outer peripheral surface of the core metal used as the fixing roll into a tapered shape of an inverted crown, as shown in FIG. The outer peripheral surface of the raw tube can be tapered. In FIG. 9, reference numeral 91 denotes a thin metal roll; 96, an outer die for ironing with a taper; and 97, a die for ironing with a rotary inner diameter. In this ironing method, the thin metal roll 91 is tapered by pressing the thin metal roll 91 from its inner peripheral surface to the outer die 96 for ironing by rotating the rotary inner diameter die 97. Further, as described above, it is needless to say that the tapered ironing outer die 96 in FIG. 9 can be easily released from the outer die by using the bulge-forming die as it is, as it is. .

FIG. 10 is a view for explaining still another bulging method in the method of manufacturing a fixing roll according to the present invention. When performing bulging on a thin metal roll, in the bulging method shown in FIG. 7 described above, processing is performed by applying a hydraulic force from the inner peripheral surface of the thin metal roll. Alternatively, the workpiece may be processed by applying a hydraulic force from the outer peripheral surface thereof.

That is, as shown in FIG. 10, a tapered bulging inner die 108 is disposed inside the thin metal roll 101, and the thin metal roll 101 is formed by an outer die 109 for forming a bulge. And processing is performed by applying a force due to liquid pressure from the outer peripheral surface from the outer side (outer peripheral surface) of the thin metal roll 101.

When a thin tube made by the method of manufacturing a fixing roll according to the present invention is used as a core of the fixing roll, the allowable stress of the material is increased, but the elastic coefficient does not change. When the fixing roll formed of the cored bar is incorporated in a fixing device and a load is applied, the fixing roll may be deformed in the axial direction. If the amount of deflection is greatly increased, the contact area (nip) between the fixing roll and the pressure roll becomes non-uniform, and when the final fixing paper is passed, paper wrinkles occur and the fixing strength at the center of the paper is reduced. The offset is weakly generated, causing a problem that the next copy is stained or an image is lost. To cope with this, in a fixing device using such a fixing roll, a mechanism (FIG. 11) for correcting the elastic deformation of the fixing roll in the axial direction is added to prevent such a problem from occurring.

Next, a description will be given of an experimental example in which a fixing roll is manufactured by the above-described method of manufacturing a fixing roll according to the present invention, incorporated as a fixing roll of a fixing device, and subjected to a fatigue test. FIG. 11 shows the structure of a fixing roll as a comparative example here. FIG. 11 shows the structure of a fixing roll made by a conventional manufacturing method. The roll core 111 is an iron roll having a diameter of 35 mm, a thickness of 0.4 mm, and a length of 380 mm. Release layer 1 on the surface
As No. 13, PFA (perfluoroalkyl vinyl ether copolymer resin) is formed in a thickness of 25 μm. The roll core 111 is a STKM having a thickness of 0.7 mm and a length of 380 mm.
It is manufactured from 11A raw tube through centerless grinding.

The fixing roll thus manufactured (FIG. 11)
Was assembled in a fixing device, and as a real mode fatigue test, idle rotation of non-sheet passing was performed. The conditions of the fixing device during the test were a set temperature of 180 ° C., a total load of 50 kgf, and a process speed of 300 mmsec. As a result of this test, after about 40 hours, we found that a roll was formed at the center of the roll,
It can no longer be used as a fixing roll.

As an experimental example under another condition, when the roll core 111 was thinned to a thickness of 0.3 mm by centerless polishing, the total runout at the center of the roll core was reduced to 20 mm.
0 μm, and the coating of the release layer was defective.

Next, an experimental example in which the fixing roll is manufactured by the method of manufacturing a fixing roll according to the present invention will be described. A roll core was prepared by the manufacturing method shown in FIGS. 5 and 6, and the structure of the roll core was made similar to the structure of the fixing roll shown in FIG. In other words, the roll is 35m in diameter
m, an iron roll having a thickness of 0.4 mm and a length of 380 mm, and PFA (perfluoroalkyl vinyl ether copolymer resin) having a thickness of 25 μm was formed on the surface of the roll as a release layer. In this case, the roll core of the thin-walled tube has a high degree of processing. Therefore, a 0.8 mm-thick and 260 mm-long STKM11A tube is used, and the shape of the fixing roll shown in FIG. It was processed to become.

The fixing roll manufactured as described above was assembled in a fixing device, and idle rotation without paper passing was performed as a real mode fatigue test. The conditions of the fixing device during the test were a set temperature of 180 ° C., a total load of 70 kgf, and a process speed of 300 mm / sec.

As a result of the test in this case, 300 hours passed after the start of the test, but the roll was not broken. Here, the number of cycles of the repetitive stress of the compression / tension is 2.9 × 106 (when one rotation of the fixing roll is one cycle). Since the fatigue limit of the metal material usually appears in 106 to 107 cycles, as a result of this test, the roll core according to the production method of the present invention is sufficiently functioning when used as a core metal of a fixing roll. It can be evaluated that the fatigue strength as the core of the fixing roll is sufficiently secured.

When such a fixing roll is used, a mechanism for correcting elastic deformation in the axial direction of the fixing roll is used together to further improve the fixing performance. That is, for example, in the fixing device shown in FIG. 1, as a mechanism for correcting the elastic deformation of the fixing roll in the axial direction, the pressing roller 40 has a structure supported at the center as shown in FIG. 120 is used. As a result, the elastic deformation is corrected, the amount of pressure applied to the fixing roll in the axial direction is made uniform, and the fixing performance can be more suitably obtained.

More specifically, an experimental example will be described. As the fixing roller 30, the fixing roller of the above-described embodiment is used, and as the pressure roller 40, a pressure rubber covered with 4 mm silicon rubber and supported at the center is used. Using the roll 120, a fixing load was tested by applying a total load of 80 kg from the bearings at both ends. In this state, the deflection at the center of the fixing roll is
0.5 mm, but the pressure roll 12 supported at the center
0, the deflection was corrected, and the nip formed by the fixing roll and the pressure roll was measured. As a result, the roll end nip was 7.0 mm, and the roll center nip was 6.4 mm.
It became. With such a configuration, a nip shape index (center nip amount / edge nip amount) of 0.9 can be obtained. Under these conditions, “Viv” manufactured by Fuji Xerox Co., Ltd.
ace550 ", sufficient fixability was obtained and no paper wrinkles were generated.

[0053]

According to the fixing device of the present invention, a thin metal roll is used as the core metal of the fixing roll, and the warm-up time is much shorter than in the past. In addition, regarding the use of a thin metal roll, it has solved the manufacturing problem caused by the insufficient strength of the thin metal roll, and at the same time, it has become possible to significantly reduce the material cost. . Further, since this also leads to an improvement in the strength of the fixing roll, a long-life fixing roll core can be provided even in a high-speed copying machine or a color copying machine using a high load.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a fixing device using a heat fixing method;

FIG. 2 is a cross-sectional view illustrating a first example of the structure of a conventional fixing roller.

FIG. 3 is a cross-sectional view illustrating a second example of the structure of a conventional fixing roller.

FIG. 4 is a diagram illustrating a process of manufacturing a core metal of a fixing roll of a fixing device;

FIG. 5 is a view for explaining a swaging method according to the method of manufacturing a fixing roll according to the present invention;

FIG. 6 is a diagram illustrating a bulging method according to a method of manufacturing a fixing roll according to the present invention;

FIG. 7 is a view for explaining another bulging method of the fixing roll manufacturing method according to the present invention;

FIG. 8 is a diagram illustrating an extrusion method according to another embodiment of the method of manufacturing a fixing roll according to the present invention;

FIG. 9 is a diagram illustrating an ironing method according to still another embodiment of the method of manufacturing a fixing roll according to the present invention;

FIG. 10 is a view for explaining still another bulging method of the method of manufacturing a fixing roll according to the present invention;

FIG. 11 is a diagram showing a configuration of a conventional fixing roll of an experimental example;

FIG. 12 is a diagram showing an example of a mechanism for correcting elastic deformation in the axial direction of the fixing roll.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inner frame of the support member of a roll, 2 ... Support rod which supports an inner frame, 3 ... Roll (sleeve), 4 ... Heat insulator, 5 ... Coil heater of a heating source, 6 ... Offset prevention layer of a release layer , 7
... Support shaft, 8 ... Roller, 9 ... Thick part, 11 ... Base tube, 1
2 ... outer diameter processing, 13 ... blasting, 14 ... offset prevention layer coating, 30 ... fixing roller, 31 ... heater, 32 ... cylindrical core, 33 ... release layer, 40 ... pressure roller, 41 ... Cylindrical cored bar, 42: heat-resistant elastic layer, 43: sheet, 44: fixed toner image, 51: metal roll to be reduced in thickness, 52: inner die for swaging, 53: die for swaging, 61: Thin-walled general-purpose roll, 62: Inner die for bulging, 64 ... Outer die for bulging, 71 ... Thin-walled metal roll, 72 ... Inner die for bulging, 75 ... Outer die for tapered bulging, 81 ... Thin-walled metal roll , 82: Extrusion die, 86: Extrusion outer die, 91 ...
Thin metal roll, 96 ... Outer die for ironing with taper, 97
... Rotating inner diameter die for ironing, 101 ... Thin metal roll, 108 ... Inner die for tapered bulging, 109 ... Outer die for bulging, 111 ... Roll core, 113 ... Release layer, 120 ... Pressing roll.

Claims (7)

[Claims] 1. A method of manufacturing a cylindrical body used as a core metal of a fixing roll, comprising: placing a cylindrical core metal inside a metal cylindrical body; and performing plastic working by applying an external force from an outer periphery of the cylindrical body. A method for manufacturing a fixing roll, characterized in that the thickness is reduced. 2. A method for producing a cylindrical body used as a core metal of a fixing roll, comprising: placing a cylindrical core metal outside a metal cylindrical body; and applying an external force from an inner periphery of the cylindrical body. A method for producing a fixing roll, characterized in that the thickness of the fixing roll is reduced. 3. A method for producing a cylindrical body used as a core metal of a fixing roll, comprising: placing a cylindrical core metal inside a metal cylindrical body; and performing plastic working by applying an external force from an outer periphery of the cylindrical body. A method of manufacturing a fixing roll, comprising reducing a thickness of a cylindrical body, and thereafter performing a tube expanding step of expanding an inner diameter of the cylindrical body to separate the cylindrical body from the core metal. 4. A method for producing a cylindrical body used as a core metal of a fixing roll, comprising: forming a cylindrical core metal outside a metal cylindrical body, and applying an external force from an inner periphery of the cylindrical body. A method of manufacturing a fixing roll, comprising: reducing a wall thickness of a cylindrical body, and thereafter performing a narrowing step of narrowing an outer diameter of the cylindrical body to separate the cylindrical body from the core metal. 5. A method of manufacturing a cylindrical body used as a core metal of a fixing roll, comprising: placing a cylindrical core metal inside a metal cylindrical body; and performing plastic working by applying an external force from an outer periphery of the cylindrical body. A method of manufacturing a fixing roll, comprising: reducing the thickness of a cylindrical body, and then expanding an inner diameter of the cylindrical body, and forming an outer periphery of the cylindrical body in an inverted crown shape and separating the cylindrical body from the core metal. 6. A method for manufacturing a cylindrical body used as a core metal of a fixing roll, comprising: placing a cylindrical core metal outside a metal cylindrical body; and performing plastic working by applying an external force from an outer periphery of the cylindrical body. A method for manufacturing a fixing roll, wherein the outer periphery of a cylindrical body is formed into an inverted crown shape to reduce the thickness of the cylindrical body, and thereafter, the cylindrical body is separated from the cored bar in a narrow tube step of reducing the inner diameter of the cylindrical body. 7. A fixing device for performing heat fixing by passing a transfer material carrying an unfixed toner image through a pressurized region formed by a pressurizing member which presses against a fixing roll having both ends pivotally supported. 7. The core metal according to claim 1 or 6, wherein a mechanism for correcting non-uniformity of a pressurized area caused by elastic deformation of the fixing roll in an axial direction when a load is applied is provided. A fixing device, which is added to a pressure body.