JP3506135B2 - Fusing device using reinforced thin cylindrical structure - Google Patents

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-walled cylindrical structure, a thin-walled cylindrical structure used in the fixing device, and a manufacturing method thereof.

[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 solvent fixing method, a pressure fixing method, and a heat fixing method are known.

The solvent fixing method has a drawback in that vapor of the solvent is emitted to cause many odors and hygiene problems.
The pressure fixing method has a drawback that the fixing property is poor as compared with other fixing methods, and that the pressure sensitive toner used here is expensive. Therefore, neither of these two fixing methods has been widely put into practical use at present.

Therefore, as a method for fixing an unfixed toner image in a copying machine using an electrophotographic process, a heat fixing method in which toner is melted by heating and the unfixed toner image is fused on a recording sheet is widely used. ing.

FIG. 1 is a diagram showing a schematic structure of a fixing device by a heat fixing method. As shown in FIG. 1, the fixing device is provided with a heater 31 inside a cylindrical cored bar 32, and a heating 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 arranged in pressure contact with the heating roller 30 and has a heat resistant elastic body layer 42 formed on the outer peripheral surface of a cylindrical core metal 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 heating roller 30 and the pressure roller 40, and fixing is performed by heat melting the additive of the toner agent.

A heating roller system for fixing by a heating roller such as a fixing device by the heating and fixing method has high thermal efficiency as compared with the hot air fixing method and the oven fixing method of other heating and fixing methods, and therefore has low power consumption (energy saving). It is excellent in high speed and high speed, and it has the least risk of flame due to paper jam.

[0007]

In a conventional heating roller type fixing device, the time required to raise the surface temperature of the heating roller from room temperature to a predetermined set temperature (hereinafter referred to as warm-up time) is 1 It takes a long time of 10 minutes. Since the warm-up time is determined by the relationship between the heat capacity of the heating roller and the applied power, the warm-up time can be shortened if the heat capacity of the heating roller is small and the applied power is large. However, the heat capacity of the heating roller is limited by the rigidity of the roller, and the input power is limited by the power consumption of the copier machine.

Generally, the electric power that can be supplied only for fixing is 3
00W to 1000W, and in order to shorten the warm-up time with the electric power in this range, the roll heat capacity of the heating roller is reduced, and this method is most effective.

By the way, if the roll diameter and the thickness of the roll core are reduced in order to reduce the roll heat capacity of the roller (cylindrical body) used in the fixing device, the roll rigidity also decreases accordingly. By the way, the roll heat capacity is
The roll rigidity is proportional to the square of the roll diameter, whereas the roll rigidity is proportional to the square of the roll diameter. When the roll rigidity decreases, the roll deforms in the axial direction (hereinafter referred to as "deflection") and in the circumferential direction (hereinafter referred to as "dent") with respect to the load applied to the roll to function as a fixing roller. Occurs. For this reason, when the roll diameter becomes equal to or smaller than a predetermined value, the roll rigidity rapidly decreases, and the load required for fixing cannot be obtained.

Of the two types of deformations described above, the function of the fixing device, especially when a roll dent occurs,
That is, the function of the fixing process of the heat fixing method, specifically, the function of nipping and conveying the paper as a heating roller,
The uniform heat transfer function to the toner layer is not performed at all, and the fixing device does not function. For this reason, the thickness must be such that a predetermined roll rigidity can be obtained so that the roll does not have a dent.

Further, in order to obtain the prescribed fixing performance, the pressure in the nip portion of the roll pair of the heating roller and the pressure contact roller is generally required to be about 0.5 to 5.0 kg / cm. . If the pressure is less than this, the gap due to the presence of irregularities on the paper or roll surface cannot be filled, and heat cannot be efficiently transferred 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 both rolls for obtaining the pressure necessary for such fixing reaches 20 to 200 kg, the roll (cylindrical body) used as the heating roller is a heating roll that can withstand this load. Roll rigidity is required, and there is a limit to reducing the roll diameter and thickness.

On the other hand, various techniques for preventing the dent of a thin roll have been conventionally proposed. Next, the technology to prevent the dents of these rolls,
A problem when such a roll is applied to a fixing device will be examined.

As a first method, for example, SAIKAI Sho 59-
128665, JP 61-4926, JP 61-59381, JP 6-130845.
As referred to in Japanese Unexamined Patent Publication (Kokai), etc., there is one in which 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. FIG. 2 is a 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 supporting member, 2 is a support rod for supporting the inner frame, 3 is a roll (sleeve), 4 is a heat insulator, 5 is a coil heater of a heating source,
Reference numeral 6 is an offset prevention layer of the release layer, and 7 is a support shaft.

In the fixing roller having the structure shown in FIG. 2, a supporting rod 2 for supporting the inner frame 1 of the reinforcing member for the roll 3 constituting the fixing roller is required, and a member having a very large internal reinforcing structure is required. Becomes For this reason, it is inevitable that the device becomes large and the cost increases. In addition, by including a large member 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. Further, since the contact portion between the inner frame 1 and the roll 3 must be made of the heat insulator 4 such as resin, it is actually a material having a small coefficient of thermal expansion when compared with a metal.
There is a risk that the inner frame 1 may fall off when the fixing roll is heated.

FIG. 3 is a sectional view for explaining a second example of the structure of a 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 and a thick portion 9 is provided. Also in this case,
As a modified example thereof, there is also a configuration in which a reinforcing rib is provided instead of the thick portion 9 that partially increases the thickness in the axial direction. A specific example of the second method is, for example, Jitsukai Sho 56-7.
Reference can be made to the descriptions in Japanese Patent Publication No. 949, Japanese Patent Laid-Open No. 57-155571, and the like.

Further, in the fixing roller having the structure as in the second method, it is necessary to carry out a partial uneven thickness processing in the axial direction inside the cylindrical structure, so that the partial thick portion is a shaft. There is a problem that the heat capacity in the direction becomes so large that the heating roller for fixing has uneven temperature distribution in the axial direction when heating the roller, and uniform fixing performance cannot be obtained. . Further, there is also a problem that the drawing process cannot be used when producing a seamless tube even during roll production, which is rather expensive.

FIG. 4 is a sectional view for explaining a third example of the structure of a conventional fixing roller. As a third method, in order to increase the rigidity of the thin-walled cylindrical body, there is disclosed in JP-A-63-267952.
As described in Japanese Patent Laid-Open Publication No. JP-A-2003-264, there is one in which a solid pipe-shaped member is inserted inside a cylindrical body. As shown in FIG. 4, the roll (cylindrical body) in this case is obtained by press-fitting the reinforcing rigid body members 11 from both ends of the conductive cylindrical member 10 as a photoconductor to increase the rigidity of the conductive cylindrical member 10. Has become. Here, the contact charging conductive rubber roller 12 is used.
Functions as a pressure roller.

In the third method, the roll is substantially high in rigidity, but since the reinforcing rigid member 11 is a solid member, when it is used as a fixing roller, a heat generating mechanism is provided inside the roll. Cannot be provided and cannot be used for a heat roller type heat roller type fixing device. Even when the heat generation mechanism is applied to a surface heating type (roll pair type) fixing device that does not have a heat generating mechanism inside the roll, there is a temperature rise loss on the surface due to heat conduction to the inside, so low power consumption (energy saving) From the viewpoint of). Further, it is expected that the reinforcing rigid body member 11 will increase the weight, and the roll rigidity is the same as when the roll thickness is designed to be large. Instead, another member is required, resulting in an increase in cost. I will end up. Also,
The reinforced rigid body member 11 is a member having a large heat capacity, and a member having a large heat capacity is provided inside the roll, which is not preferable from the viewpoint of reducing the warm-up time.

FIG. 5 is a sectional view for explaining a fourth example of the structure of a conventional fixing roller. As a fourth method, for example, as described in JP-A-1-126417, the thin-walled cylindrical structure here is inscribed with an inner core formed of a thin plate inside a thin-walled cylindrical outer cylinder. Let it be fixed. As shown in FIG. 5, the cross section of this structure includes a triangular prism-shaped inner core 14 formed of a thin plate and a cylindrical outer cylinder 13.
It is inscribed inside and fixed inside. With the structure of the fourth method, when used as a fixing roll of a heat fixing device, it becomes difficult to dispose an infrared lamp heating device as a heating source inside. Also, from the viewpoint of increasing the strength of the roll, the rigidity in the roll axial direction increases, but the dent in the roll circumferential direction due to the thinning is
However, it cannot be sufficiently prevented in the part not inscribed, which is not preferable from the viewpoint of reliability.

The present invention has been made in view of the above various problems, and an object of the present invention is to prevent the internal reinforcing member from falling off in a thin-walled cylindrical structure which receives an external force at its circumferential portion. It is an object of the present invention to provide a small-sized high-performance fixing device using a thin-walled cylindrical structure having a structure that does not cause a problem and is sufficiently prevented from being dented in the circumferential direction due to thinning. Another object of the present invention is to provide a thin-walled cylindrical structure used in a fixing device and a method for manufacturing the thin-walled cylindrical structure.

Another object of the present invention is to use a fixing roll having a thin cylindrical structure as a fixing roll of a fixing device,
In order to obtain a predetermined strength, at least one support member is provided on the inner peripheral surface of the thin-walled cylindrical structure, or if the thickness is partially increased by uneven thickness processing, It is an object of the present invention to provide a fixing device that prevents local temperature unevenness on the surface of a fixing roll in a thick portion of a thick portion and prevents defective fixing performance in the vicinity of the thick portion.

[0023]

In order to achieve the above object, the fixing device according to the present invention has, as a first feature, a pressurizing roll which is in pressure contact with a fixing roll including a heater therein. In a fixing device that heats and fixes a recording paper onto which a non-fixed toner image has been transferred in a pressure region, as a fixing roll, at least one or more supporting members are press-fitted into a thin-walled cylindrical structure. A cylindrical structure is used in which a part of the outer peripheral surface is held in pressure contact with the inner surface of the thin cylindrical structure.

As a second feature, according to the present invention
The cylindrical structure used for the fixing device is a thin-walled cylindrical structure that receives an external force at a circumferential portion, and at least one or more supporting members are press-fitted into the thin-walled cylindrical structure, and a part of the outer peripheral surface of the supporting member is It is characterized in that it is held in pressure contact with the inner surface of the cylindrical structure.

As a third feature, this cylindrical structure is a thin-walled cylindrical structure, and in the case where at least two supporting members are arranged in the thin-walled cylindrical structure, the distance between the supporting members is P. When the length of the cylindrical structure is L, the outer diameter of the cylindrical structure is D, and the wall thickness of the cylindrical structure is t, L> 200 mm, t / D <0.02, P <150m
It is characterized by satisfying the condition of m 1.

As a fourth characteristic, in the thin-walled cylindrical structure here, the shape of the supporting member is a ring shape, and as a fifth characteristic, at least the outer peripheral surface shape in the axial cross section of the supporting member. It is characterized in that a part thereof has a notch shape or a projection shape. A sixth feature is that at least a part of the outer peripheral surface shape in the radial cross section of the support member is a cutout shape or a projection shape.

As a seventh feature, in the method of manufacturing a cylindrical structure, when a plurality of supporting members are arranged in a thin-walled cylindrical structure, the inner diameter of each supporting member is made different, and the inner diameter is large. It is characterized in that they are arranged in order from. In addition, in this case, as an eighth characteristic, the central axis of the supporting member and the central axis of the cylindrical structure are substantially coaxial, the supporting member is disposed at a predetermined position of the cylindrical structure, and then the cylindrical The structure may be plastically deformed to reduce the inner diameter of the cylindrical structure.

As a ninth feature, in the method of manufacturing a cylindrical structure, when a plurality of supporting members are arranged in the thin cylindrical structure, the supporting member is inserted into the thin cylindrical structure. Sometimes, the central axis of the supporting member is made non-parallel to the central axis of the thin-walled cylindrical structure, and after the supporting member reaches a predetermined position of the thin-walled cylindrical structure, the central axis of the supporting member and the thin-walled cylindrical structure. It is characterized in that the central axis of the body is arranged substantially coaxially.

In this case, the tenth feature is that
In the method for manufacturing a cylindrical structure, at least one of the thin-walled cylindrical structure and the supporting member is deformed in the circumferential direction, and the supporting member is disposed inside the thin-walled cylindrical structure. Also,
The eleventh feature is that the shape of the support member of the thin-walled cylindrical structure is an inverted crown shape in the inner diameter of the axial cross section.

As a twelfth feature of the fixing device of the present invention, a recording paper on which an unfixed toner image is transferred is applied to a pressure area formed by a pressure roller that is in pressure contact with a fixing roller including a heater. In the fixing device for passing and heating and fixing, the support member arranged in the fixing roll has a coefficient of thermal expansion equal to or larger than that of the fixing roll. Alternatively, a thirteenth feature is that the end portion of the fixing roll is plastically deformed.

In this case, as a fourteenth feature,
It is characterized in that a fixing roll having an outer diameter processed into a predetermined thickness after the support member is disposed is used. A fifteenth feature is that, in a thin-walled cylindrical structure, an outer diameter is machined to a predetermined wall thickness after disposing a supporting member. As a sixteenth feature, in the fixing device of the present invention,
It is characterized in that a mechanism for correcting elastic deformation of the fixing roll in the axial direction is added.

As a seventeenth feature of the fixing device of the present invention, a transfer material carrying an unfixed toner image in a pressure contact area formed between a fixing roll having both ends axially supported and a pressure member in pressure contact with the fixing roller. In the fixing device for heating and fixing by passing through, when a thin-walled cylindrical structure having one or more thick-walled portions on the inner peripheral surface of the thin-walled cylindrical structure is used as the fixing roll, When the heat capacity of the protrusion of the roll portion is C1 (cal / ° C) and the heat capacity of the roll portion excluding the protrusion of the thick portion is C2 (cal / ° C), "(C1 / C
2) It is characterized by satisfying the condition of <10 ”.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, modes for carrying out the present invention will be specifically described with reference to the drawings. 6 and 7 are cross-sectional views illustrating the basic structure of the thin cylindrical structure used in the fixing device of the present invention. 6 and 7, reference numeral 15 is a thin-walled cylindrical structure, and 16 is a support member. That is, in the basic structure of the thin-walled cylindrical structure used in the fixing device according to the present invention, as shown in FIG.
However, by contacting the inside of the thin-walled cylindrical structure 15 and press-fitting it, part of the outer peripheral surface of the support member 16 is held in pressure contact with the inner surface of the thin-walled cylindrical structure 15.
At least one support member 16 is provided in the thin-walled cylindrical structure 15. Here, since the support member 16 is held in a press-fitted state, the decrease in the circumferential rigidity of the cylindrical structure due to the thinning of the cylindrical body is significantly improved.

When the support members 16 are arranged on the thin-walled cylindrical structure 15, the number of the support members is plural and the distances between the respective support members 16 are set in order to increase the rigidity more effectively. As shown in FIG. 6, the distance between the support members 16 is P, the length of the thin-walled cylindrical structure 15 is L, the outer diameter of the cylindrical structure is D, and the thin-walled cylinder is When the thickness of the structure 15 is t, L> 200 mm, t / D <0.02, P <150 m
satisfy the condition of m 2.

Next, the shape of the support member 16 arranged in the thin-walled cylindrical structure 15 in a state of being press-fitted will be described. FIG. 8 is a diagram showing a first example of the shape of the support member, and FIG. 9 is a diagram showing a second example of the shape of the support member.
FIG. 10 is a diagram showing a third example of the shape of the support member.

In order to increase the rigidity of the thin-walled cylindrical structure 15, the support member 16 arranged in a press-fitted state inside is
For example, as shown in FIG. 8, the entire shape is a narrow cylindrical shape (ring shape). Further, when arranged inside, in order to prevent the supporting member from falling off due to deformation of the thin-walled cylindrical structure, the outer peripheral surface of the supporting member has a cross section in the axial direction rather than a simple cylindrical shape. At least part of the shape of the outer peripheral surface is notched or protruding so that when the support member is press-fitted, the protruding part bites into part of the inner surface of the thin-walled cylindrical structure.

That is, as shown in FIG. 9, the supporting member 17 thus deformed has at least a part of the shape of the outer peripheral surface of the cross section in the axial direction which is notched or projected. In other words, the shape of the outer peripheral surface of the axial cross section is not circular. The same applies to the shape of the cross section in the radial direction. That is, as shown in FIG. 10, the support member 18 deformed in another form has a cutout shape or a projection shape in at least a part of the shape of the outer peripheral surface of the cross section in the radial direction. In other words, the shape of the outer peripheral surface of the radial cross section is not linear. By making the shape of the outer peripheral surface of the support member partially have such a protruding portion, the contact strength between the inner peripheral surface of the cylindrical structure and the outer peripheral surface of the support member is significantly improved when the support member is press-fitted. Therefore, it is possible to prevent the support member from falling off.

Next, a method of manufacturing a cylindrical structure for press-fitting and holding such a supporting member in a thin-walled cylindrical structure will be described. FIG. 11: is a figure explaining the 1st example of the manufacturing method of the cylindrical structure which concerns on this invention. When a plurality of support members are press-fitted into the thin-walled cylindrical structure, for example, when three or more support members are press-fitted into the thin-walled cylindrical structure, as shown in FIG. A plurality of support members whose inner diameters of the individual support members 21 to 23 are gradually reduced are used. This allows
The support members 21 to 23 and the support jigs 25 to which are press-fitted in advance.
27 does not interfere with each of the support members 21 to 2
3 can be supported, and the plurality of support members 21 to 23 can be sequentially press-fitted by the press-fitting jig 24.

FIG. 12 is a diagram for explaining a second example of the method for manufacturing a thin-walled cylindrical structure according to the present invention. In order to ensure that the support member is press-fitted into the thin-walled cylindrical structure and a part of the outer peripheral surface of the support member is held in pressure contact with the inner surface of the thin-walled cylindrical structure, the thin-walled cylindrical structure is secured. In the body manufacturing method, as shown in FIG. 12, when manufacturing a thin-walled cylindrical structure in which a plurality of supporting members are arranged, the axis of the supporting member 46 and the axis of the cylindrical structure 45 are made substantially coaxial. After being arranged (press-fitted) at a predetermined position, plastic working is performed so as to reduce the outer diameter of the cylindrical structure 45. As a result, the support member can be reliably brought into pressure contact with the cylindrical structure 45.

13 and 14 are views for explaining still another example of the method for manufacturing a thin-walled cylindrical structure according to the present invention. Since the support member is press-fitted into the thin-walled cylindrical structure and a part of the outer peripheral surface of the support member is held in a pressed state with respect to the inner surface of the thin-walled cylindrical structure, the manufacturing method here is As shown in FIG. 13, when the support member 51 is press-fitted and arranged in the thin-walled cylindrical structure 50, the axis of the support member 51 and the axis of the cylindrical structure 50 are made non-parallel to each other, and the support member 51 is arranged at a predetermined position. By changing the attitude of the support member 51 so that the axis of 51 and the axis of the cylindrical structure 50 are substantially coaxial, the contact area between the outer peripheral surface of the support member 51 and the inner peripheral surface of the cylindrical structure 50 increases, and The support member 51 can be press-fitted into the pressure-contacting state.

In this case, when disposing the support member in the cylindrical structure, that is, in the first half step shown in the upper side of FIG. 13, as shown in FIG. By deforming at least one of them in the circumferential direction, the support member 51 is arranged at a predetermined position inside the cylindrical structure 50. By the thus deformed so by arranging to Turkey, it is improved remarkably workability. That is, in this step, when the cylindrical structure 50 and the supporting member 51 are obliquely shaded from the axial direction of the cylindrical structure 50, a large difference occurs between the maximum inner diameter of the cylindrical structure 50 and the minimum inner diameter of the supporting member 51. The process of disposing the support member 51 in the first half on the cylindrical structure 51 becomes very easy to perform.

Further, in order to further facilitate the work of disposing the supporting member on the cylindrical structure, a cylindrical structure having an inverted crown shape in the inner diameter in the axial direction may be used. FIG. 15 is a diagram illustrating a fourth example of the method for manufacturing a thin-walled cylindrical structure according to the present invention. As shown in FIG. 15, a cylindrical structure 60 having an inverted crown shape is used in the inner diameter in the axial direction. By using the cylindrical structure 60 having such a shape, a plurality of support members 61 can be press-fitted in order from one side. Moreover, the tolerance design between the inner diameter of the cylindrical structure 60 and the outer diameter of the support member 61 becomes very easy. In the display shown in FIG. 15, in order to facilitate understanding of the difference between the shape of the aforementioned cylindrical structure and the shape of the thin-walled cylindrical structure 60, the center part and the end part are drawn in an extremely different manner. However, as in the dimensional example of the example (FIG. 29) described later, when the cylindrical structure 50 here is a cylindrical body having a length of 400 mm, the end portion has a diameter of 35.4 mm, and The diameter is 35.0 mm.

By using the cylindrical structure with the reinforcing member capable of largely preventing the depression in the circumferential direction due to the thinning in the fixing device, the worm can be formed without increasing the size of the fixing device. The uptime can be significantly shortened, and at the same time, the applied load can be significantly increased. Therefore, the fixing device having excellent fixing performance can be configured.

Since the fixing device is premised on applying heat to the fixing roll of the cylindrical structure at the time of fixing, in the heating process, the material used as the cylindrical structure of the fixing roll and its supporting member is changed. Due to the difference in the coefficient of thermal expansion, the supporting member may fall off when the coefficient of thermal expansion of the supporting member is smaller than that of the cylindrical body.

The possibility of such drop-off is very low because the supporting member here is arranged in a state of being press-fitted into the thin-walled cylindrical body, but in contrast to this, in the fixing roll, This can be prevented by using a support member having a larger coefficient of thermal expansion than the coefficient of thermal expansion. That is, by increasing the coefficient of thermal expansion of the supporting member to be larger than that of the fixing roll, the thermal expansion of the supporting member is increased during heating, and the thermal stress at the contact portion is increased, so that the fixing roll and the supporting member are more firmly coupled. As a result, the fear of dropping will be resolved.

When a plurality of supporting members are arranged in the thin-walled cylindrical structure, the supporting members at the ends of the cylindrical structure can be omitted by bending the ends of the thin-walled cylindrical structure. . That is, as shown in FIG. 16, in this case, in the thin-walled cylindrical structure 70, the supporting member 71 disposed inside first is press-fitted, and the inner surface of the cylindrical structure 70 is surrounded by the peripheral surface of the supporting member 71. After arranging the support members in a state where a part of the above is pressed, the end members 70a of the thin cylindrical structure 70 are replaced with the support members at both ends without disposing the support members at both ends.
Is plastically deformed and bent in the axial direction, which is easy to process. As a result, without impairing the dent prevention function,
It is possible to improve manufacturability and reduce costs.

In the cylindrical structure according to the fixing device of the present invention, the supporting member is press-fitted so that the supporting member is arranged inside the thin-walled cylindrical structure in a pressed state. Therefore, when the degree of thinness is large (when the thickness is very thin), the presence of the support member 81 may become apparent on the outer peripheral surface of the cylindrical structure 80, as shown in FIG. In such a case, when such a cylindrical structure is used as a fixing roll, the non-uniformity of the shape of the outer peripheral surface of the fixing roll causes deterioration of image quality. In this case, as shown in FIG.
As shown in, when the thin-walled cylindrical structure 80 is used as a fixing roll by arranging the support member 81 on the thin-walled cylindrical structure 80 and then processing the outer diameter of the thin-walled cylindrical structure 80 to a predetermined wall thickness. Remove the unevenness of the outer shape of the fixing roll. Accordingly, when the thin-walled cylindrical structure into which the support member is press-fitted is used as the fixing roll, the fixing roll having a good outer peripheral surface shape can be obtained.

By the way, it is very difficult to reduce the thickness of the cylindrical structure. The cause is mainly that a dent is generated in the cylindrical structure during processing, but in the structure of the cylindrical structure according to the present invention, the strength against the dent is increased by disposing the support member. In the method of manufacturing a thin-walled cylindrical structure,
As shown in FIG. 19, a cylindrical structure 90 having a certain thickness
On the other hand, the support member 91 is first press-fitted so that the support member 91
After arranging the thin outer diameter of the fixing roll to a predetermined thickness
May be processed. As a result, the cylindrical structure can be made significantly thinner than in the previous step (compared to the case where there is no support member).

Further, the effect of arranging the supporting member on the thin-walled cylindrical structure can largely prevent the fixing roller from being dented, but at the same time, the fixing roller is also flexibly deformed in the axial direction. Therefore, when used as a fixing roll of a fixing device, by adding a conventionally known mechanism for correcting elastic deformation in the axial direction, it is possible to use up to the strength limit of the entire fixing roll.

Next, the characteristics when the thin-walled cylindrical structure manufactured as described above is used as a fixing roll of a fixing device will be described. FIG. 20 is a diagram illustrating a roll load application device for a fixing roll. The thin-walled cylindrical roll 201 of the fixing roll here has a diameter of 35 mm and a wall thickness of 0.55.
It is an iron core having a length of 335 mm and a length of 335 mm. Both ends of the thin-walled cylindrical roll 201 are supported by bearings 202. On the other hand, the load applying bar 203 made of iron has a sufficient strength to apply a load to the thin-walled cylindrical roll 201 by a load applying mechanism section (not shown) without causing bending. A strain gauge was attached to the outer peripheral portion of the thin-walled cylindrical roll 201, and the amount of strain in the axial direction and the circumferential direction at each location was measured using a cylindrical roll load application device.

As shown in FIG. 21, the measurement positions are as follows: the end (A series) and the center (B) on the outer peripheral surface of the thin-walled cylindrical roll 210.
21A and 21B, the upper position (series of subscript 1), the middle position (series of subscript 2), and the lower position (series of subscript 3), that is, in FIGS. Position (A1, A2, A3, B shown in (B)
1, B2, B3), a strain gauge (manufactured by Kyowa Dengyo Co., Ltd .: not shown) is attached, and the amount of strain in the axial direction and the circumferential direction at each position is measured using the above-described cylindrical roll load application device. , The measurement results are shown in FIGS. 22 (A), (B),
It is shown in (c).

The position of the A series here is a rough end,
The position of the B series is approximately at the center. Moreover, the strain amount data showed an absolute value regardless of compression or tension. As is clear from the measurement results of FIG. 22, the largest increase rate of the strain amount is in the central part of the cylindrical roll and in the circumferential direction at the position (B3) in contact with the load applying bar. Is. Naturally, the permanent strain (plastic deformation) first occurs in the same place and in the same direction.

Here, a support member having a thickness of 0.8 mm and a width of 2.0 mm as shown in FIG. 23 is press-fitted into a position corresponding to the position (B3) where the rate of increase in strain is the largest, and the amount of strain is again measured. Was measured, the amount of strain in the central portion in the circumferential direction was 1/3. That is, the withstand pressure is about 3
This is a double increase. The shape of the internal support member to be press-fitted does not necessarily have to be all in contact with the inner surface of the thin-walled cylindrical roll, and even if it has a deformed shape as shown in FIG. 24, there is no problem (decrease in dent preventing function). ) Did not occur. However, in consideration of easiness in manufacturing and cost, the ring-shaped one as shown in FIG. 23 is preferable.

As a method of increasing the dent prevention performance of the thin-walled cylindrical roll, a plurality of support members are provided by being press-fitted inside the thin-walled cylindrical roll. In the case of a thin-walled cylindrical roll supported at both ends, as the applied load increases, permanent deformation in the circumferential direction occurs before that in the axial direction. Therefore, it is preferable if the permanent set in the circumferential direction can be generated under the same load condition as that in the axial direction. That is, it means that the load bearing performance is improved.

FIG. 25 is a diagram for explaining an experimental example for measuring the degree of deformation when the positions where a plurality of supporting members are arranged are changed in the thin-walled cylindrical structure. For example, as shown in FIG. 25A, two ring-shaped support members shown in FIG. 23 are arranged at the center of the thin-walled cylindrical roll, and the distance P between the two support members is changed. Then, the amount of strain at the position (B3) at the center of the thin-walled cylindrical roll was measured with the applied load being 100 kgf in the same manner as in the above case. According to the result, as shown in FIG. 25 (B), when the distance P between the supporting members is 150 mm or less, the strain amount in the circumferential direction at the position (B3) at the central portion is the strain amount in the axial direction. Almost matches. However, when the distance P between the supporting members is larger than 150 mm, the amount of strain in the axial direction at the position (B3) in the central portion becomes constant, so the difference between the amount of strain in the axial direction and the amount of strain in the circumferential direction is large. On the contrary, when the load is increased, the permanent set in the circumferential direction is generated first.

This tendency is related to the length L, the outer diameter D, and the wall thickness t of the thin-walled cylindrical roll. According to the experiments conducted by the inventors of the present invention, L> 200 mm, In addition, it was found to be optimal under the condition of t / D <0.02.

Further, when a support member is provided inside to reinforce the thin-walled cylindrical roll, how to press-fit the support member inside the thin-walled cylindrical roll is a very important problem as described above. In the method for manufacturing a cylindrical structure used in the fixing device of the present invention, two points, "preventing the supporting member from falling off" and "pressing in a plurality of supporting members" are particularly important.

First, a structure for preventing the supporting member press-fitted into the thin-walled cylindrical roll from falling off will be described. The falling of the support member press-fitted into the thin-walled cylindrical roll is mainly caused by the external force. As the external force, a constant load (static load) is applied to the structure of the thin-walled cylindrical roll, a load (dynamic load) is applied due to vibration or rotation, and a load (impact force) caused by an object colliding. Occurs when is added. Therefore, in order to prevent the supporting member from falling off, since the inner peripheral surface of the thin-walled cylindrical roll and the contact portion of the outer peripheral surface of the supporting member are held in pressure contact, the strength of the contact pressure is increased. .

For this purpose, the contact strength can be easily increased only by changing the shape of the outer peripheral surface of the support member. For example, as shown in FIG. 26, the supporting member is formed in a shape such that the cross section of the outer peripheral surface in the axial direction is a projection. When the support member having such a shape was press-fitted into the thin-walled cylindrical roll, it did not fall off due to external force.

Alternatively, as shown in FIG. 27, the outer peripheral surface is shaped so as to have a projecting cross section in the circumferential direction. When press-fitted into the thin-walled cylindrical roll of the supporting member having such a shape,
There was no dropout due to external force. As the shape of the support member, the example of the shape of the outer peripheral surface of two types has been described, but the shape of the support member is not particularly limited to the projection shape, and the contact portion between the inner surface of the thin-walled cylindrical roller and the outer peripheral surface of the support member. Obviously, any other shape may be used as long as it has a shape that enhances the meshing in the pressed state.

As described above, when a support member is provided inside to reinforce the thin-walled cylindrical roll, how to press-fit the support member into the thin-walled cylindrical roller is a very important problem. In this case, "press-fitting a plurality of supporting members" is also very important. When only one supporting member is press-fitted into the thin-walled cylindrical roller, the supporting jig for the supporting member and the pressing jig for the supporting member are used as shown in FIG.
As shown in FIG. 8, a cylinder (solid or hollow) having an outer diameter smaller than the inner diameter of the thin-walled cylindrical roll may be used and pressed from both sides of the thin-walled cylindrical roll. However, in that case, the outer diameter of the support member is substantially the same as the inner diameter of the thin-walled cylindrical roll, or slightly larger so that a tight fit is obtained.

Therefore, as described with reference to FIG. 13, by inserting the support member obliquely (so that the axes are not parallel) with respect to the axis of the thin-walled cylindrical roll, the inner peripheral surface of the thin-walled cylindrical roll is reduced friction acting between the outer peripheral surface of the support member can be easily carried out the press-fit. Alternatively, FIG.
4, at least one of the support member and the thin-walled cylindrical roll is elastically deformed to form a gap between the support member and the inner surface of the thin-walled cylindrical roll, thereby facilitating the disposition to a predetermined position. To do so. This improves the workability of manufacturing. It was possible to easily press-fit the supporting member as shown in FIG. 23 into the thin-walled cylindrical roll by these methods using the jig having the dimensions shown in FIG.

When there are a plurality of supporting members press-fitted into the thin-walled cylindrical roll, the supporting member inserted first and the supporting member inserted later or the supporting member inserted first and the jig or the supporting member and the thin-walled cylindrical roll are inserted. Interference problem occurs. For example, the inner diameter is 34 mm, the outer diameter is 35 mm, and the length is 335 m.
23, four ring-shaped supporting members as shown in FIG. 23 were simultaneously arranged in predetermined positions on the iron thin-walled roll, and as shown in FIG. 12, swaging (drawing) was performed and press-fitted. However, the problem of interference did not occur when a plurality of press-fitted parts were press-fitted. As a method of avoiding the interference between the support member and the jig, the shape of the support member is set so that the width of the ring-shaped support member shown in FIG. 23 is 2 mm, 3.5 mm, 5 mm.
There are three types, and the outer diameter of the supporting jig corresponding to this is 33.
As 3 types of 8mm, 32.3mm, 30.8mm,
When the support members were press-fitted in order by the manufacturing method as shown in FIG. 11, the problem of interference did not occur.

Further, as shown in FIG. 29, by bulging, the inner diameter is tapered so that it has a crown shape.
Fig. 30 shows a thin iron roll with a uniform thickness (0.4 mm).
As shown in (C), when a support member having a width of 0.8 mm and a support member having dimensions as shown in FIGS. 30 (a) and 30 (b) are press-fitted in this order on each side, interference of There was no problem, and it was possible to press fit into the prescribed position.

FIG. 31 is a sectional view for explaining the structure of a fixing device using the thin-walled cylindrical structure according to the embodiment of the present invention. The fixing device shown in FIG. 31 is a fixing roll 1 having a thin cylindrical structure.
01 is 40 mm in diameter, 0.25 mm in wall thickness, and 380 in length
Fluorine resin (Teflon (registered trademark) / trade name of DuPont) is 30 μm as a release layer on the iron core 103 of mm.
It is coated to the thickness of. In addition, the fixing roll 101
The inside of each of the support members 10 has an insertion interval of 80 mm.
5 is press-fitted.

A heating source 106 is provided at the center of the fixing roll 101.
As an infrared lamp of 100 v and 1000 w, a temperature controller (not shown) controls the infrared lamp so that the temperature of the infrared lamp is always 150 ° C. The warm-up time at this time can be 10 seconds because the thin cylindrical body is used as the fixing roller 101. The fixing roll 101 is driven by a drive motor (not shown) at 250 mm / s.
Driven at the speed of. The pressure roll 102 has an outer diameter of 3
2mm, thickness 6mm, length 380mm iron core 104
Is coated with a silicon rubber 107 having a thickness of 4.0 mm, and a total load of 50 kg is applied from the bearing portions at both ends.

When the nip area is measured in this state, the roll end nip is 6.0 mm and the roll center nip is 5.4 mm. With such a structure, a nip shape index of 0.9 can be obtained. In this state, when the unfixed toner image 109 imaged by the copying machine "Viverse 550" manufactured by Fuji Xerox Co., Ltd. was fixed, sufficient fixing property was obtained and no paper wrinkles occurred.

As a comparative example, when the pressure roll described above is rotated in contact with a conventional fixing roll in which a supporting member is not press-fitted into the fixing roll, a load of 10 kg causes permanent deformation of the fixing roll due to a dent. However, it could not be fixed.

Further, in the case of thinning the cylindrical structure, in the case of a seamless steel pipe, drawing is performed with a wall thickness of approximately 0.7 mm or more, and in order to further thin the wall thickness,
Outer diameter processing is performed using a lathe or centerless grinder.
However, there is a limit in reducing the wall thickness without deteriorating the roundness. The cause thereof is the dent deformation of the cylindrical structure as a workpiece due to the decrease in the circumferential rigidity of the cylindrical structure. In the present invention, on the other hand, the support member is press-fitted inside the cylindrical structure to prevent dent deformation.

Numerical examples of specific experiments will be described. In this experimental example, a thin-walled cylindrical roll has an outer diameter of 3
An iron core having a diameter of 5.3 mm, an inner diameter of 33.9 mm, a wall thickness of 0.7 mm, and a length of 335 mm was used. The circularity of the central portion of this thin-walled cylindrical roll was 60 μm. Four supporting members having a thickness of 0.8 mm and a width of 2 mm illustrated in FIG. 23 were press-fitted into this thin-walled cylindrical roll at equal intervals. And the outer diameter is 34.3.
in-feed with a centerless grinding machine
When grinding was performed, it was possible to perform processing without problems such as generation of cracks in the roll during the processing. The quality of the processed roll is 34.36mm in outer diameter and 8μ in roundness at the center.
m was good.

As a comparative example, when the above-mentioned thin-walled cylindrical roll was processed without press-fitting the supporting member, the quality of the processed roll was 35.54 mm in outer diameter and 250 μm in roundness at the central portion. It was bad.

Further, in the fixing device shown in FIG. 31, as shown in FIG. 32, the pressure roll is changed to a roll supporting at the center. The fixing roll has a diameter of 30 mm, and other numerical values are the same. Further, inside the thin-walled fixing roll, the insertion interval is 80 mm, the outer shape is 39.95 mm, and the width is 0.
A supporting member having a thickness of 8 mm and a thickness of 3 mm is press-fitted. A total load of 80 kg was applied from the bearings at both ends. In this state, the deflection at the central portion of the fixing roll reached 0.05 mm, but this deflection was corrected by the pressure roll shown in FIG. 32, and when the nip was measured, the roll end nip was 7.0 mm. The roll center nip is 6.4 mm, and with such a configuration, a nip shape index of 0.9 can be obtained. Further, no dent in the circumferential direction of the fixing roll was observed. In this state, when the unfixed toner image 9 imaged with "Vivace 550" manufactured by Fuji Xerox Co., Ltd. was fixed, sufficient fixing property was obtained and paper wrinkles did not occur at all.

By the way, as described above, in the embodiment of the present invention, with respect to the dent deformation of the cylindrical structure caused by the decrease in the rigidity of the cylindrical structure in the circumferential direction, A support member is press-fitted inside to prevent dent deformation. When such a thin cylindrical structure is used as a fixing roll, the press-fitted support member part partially becomes a thick part in the axial direction of the cylindrical structure, and this thick part is generated when the fixing roll is heated up. In particular, at the beginning of use in the fixing device, this may cause local temperature unevenness on the surface of the fixing roll, which may cause a decrease in fixing performance.

That is, when a thin-walled cylindrical structure which receives an external force at the circumferential portion is used as a fixing roll, the thickness of the inner circumferential surface is increased at least at one or more places to sufficiently reduce the dent in the circumferential direction due to the thinning. When a thin fixing roll having a structure that prevents the use of the fixing roll is used, local temperature unevenness may occur on the surface of the fixing roll, resulting in defective fixing near the thick portion. On the other hand, in the embodiment of the present invention,
As described below, the heat capacity condition between each member in the thick portion and the roll portion is satisfied.

In the embodiment of the fixing device of the present invention, that is, in the pressure area formed between the fixing roll supported at both ends and the pressure body in pressure contact with it, the toner image is carried and the transfer material is loaded. In the fixing device for passing and heating and fixing, the fixing roll is a thin metal roll, and the projecting portion heat capacity of the thick portion is C1 (Cal /
C), when the heat capacity of the roll portion excluding the protruding portion in the thick portion is C2 (cal / ° C), "(C1 / C2) <1
The material and shape satisfy the condition of "0".

As a result, when all the constituent elements of the fixing device are at about room temperature, the first copy immediately after the power is turned on and started up, especially in the vicinity of the thick portion, temperature unevenness occurs and the thick portion is thick. Although the phenomenon that the degree of fixing is deteriorated occurs near the portion, this phenomenon can be prevented.

FIG. 33 is a diagram showing an example of a thin cylindrical structure having a thick portion used as a fixing roll in the embodiment of the present invention. In other words, as a result of press-fitting the supporting member into the thin-walled cylindrical structure in order to prevent the thin-walled cylindrical structure from indenting and deforming, FIG.
As shown in FIG. 5, a cylindrical structure in which a thick portion is partially formed in the axial direction is used as the fixing roll of the fixing device here.

In FIG. 33, reference numeral 301 is a roll portion of a fixing roll having a thin metallic cylindrical structure, and 302 is a thick portion thereof. Further, FIG. 34 is an enlarged view showing a thick portion of an axial cross section of the fixing roll of the fixing device in an enlarged manner.
As shown in FIG. 34, the protrusion of the thick portion of the thin-walled cylindrical structure used as the fixing roll here means a protrusion 304 of a portion protruding from a substantially uniform thickness that occupies most of the fixing roll. The roll portion excluding the projecting portion in the thick portion means the flat portion 303 excluding the projecting portion 304 in the thick portion.

Here, an example in which the thickness is increased in the circumferential direction of the roll will be described, but it is assumed that the thickness is not limited to the thick portion having the shape shown in FIG. Including. Further, it also includes a roll having a spiral wall thickness. In addition, regarding the shape of the protruding portion 304 that is a thick portion, although the cross-section has a semicircular shape in FIG. 34, it may have a polygonal shape such as a rectangular shape, a triangular shape, or a trapezoidal shape. However, the same can be applied.

[0080] Figure 35 is a diagram showing changes in the temperature rise at the time of start-up of the thin portion roll surface temperature and the thick portion roll surface temperature from (when the power is turned on) until the warm-up is complete. FIG. 36 is a diagram showing a temperature distribution immediately after warming up in the vicinity of the thick portion of the fixing roll. Fig. 35
As shown in, the temperature rise of the thin portion that occupies most of the fixing roll is faster than that of the thick portion immediately after the power is turned on, so that the heat accumulated in the fixing roll portion near the thick portion is Phenomenon of flowing into. So this is
This is because, among structural materials (metal, resin, rubber, ceramic, etc.), the thermal conductivity of metal is very large, and the effect of this phenomenon on the temperature distribution in the axial direction of the metallic fixing roll is extremely large.

As a result, as shown in FIG. 36, the temperature distribution immediately after warming up in the vicinity of the thick portion becomes extremely uneven. In FIG. 36, an enlarged view of the thick portion 305 is shown corresponding to the temperature distribution of the roll surface temperature. As described above, the temperature distribution immediately after warm-up in the vicinity of the thick portion of the fixing roll becomes very uneven, so if the fixing process is performed in this state, fixing failure may occur near the thick portion. Become.

However, the heat inflow phenomenon immediately after the power is turned on is dominated by the ratio of the heat capacity of the protruding portion in the thick portion to the heat capacity of the roll portion excluding the protruding portion in the thick portion. It is known from the experimental results such as. Therefore, when the thin-walled cylindrical structure here is used as a fixing roll in a fixing device, the heat capacity at the protruding portion of the thick-walled portion is C1 (cal
/ C) and the heat capacity of the roll part excluding the protruding part in this thick part is C2 (cal / C), "(C1 / C2)
By setting the heat capacity ratio in the range satisfying the condition of <10>, the temperature distribution unevenness in the axial direction is improved to a range that can be practically used.

Next, the results of experiments conducted by the present inventors will be specifically described. In this case, in order to facilitate understanding, a description will be given with reference to a comparative example with the conventional case where uneven temperature distribution occurs.

FIG. 37 is a view for explaining the shape of a thin-walled cylindrical structure having a thick wall portion as a fixing roll of a fixing device for comparison. As shown in FIG. 37,
The shape of the thin-walled cylindrical structure of the fixing roll here is as a release layer 309 on the surface of the core of the thin-walled cylindrical iron-made structure having a diameter of 35 mm, a roll portion 306 having a wall thickness of 0.3 mm, and a length of 335 mm. Use is made of PFA (perfluoroalkyl vinyl ether copolymer resin) molded to a thickness of 25 μm. In order to increase the rigidity of the inside of the roll portion 306, a projecting portion 308 is partially formed by uneven thickness processing, and the thick portion 307 including the projecting portion 308 has a width of 1 mm and a height of 4 mm.
Are provided at four locations in the axial direction, and the intervals are provided at a pitch of 100 mm.

The thin-walled cylindrical structure having such a shape is mounted as a fixing roll of a fixing device (not shown), and the surface temperature of the central portion (non-thick portion) and thick portion 307 of the roll portion 306 is radiated. A non-contact thermometer (manufactured by Keyence Corp.) was used. Other conditions of the fixing device at the time of measurement are that the preset temperature is 170 ° C., the initial temperature of the fixing device is 25 ° C. (room temperature), the input power is 1000 W, and the fixing roll and the pressure roll are latched by the fixing roll. 170 ° C
And after reaching. After the latching, both rolls are driven to rotate. According to the experimental results in this case, the temperature transition 310 at the central portion and the temperature transition 311 at the thick portion shown in FIG. 38 were obtained.

In this case, when the set temperature is reached (after 20 seconds), each temperature is about 3 as shown in FIG.
There is a temperature difference of about 0 ° C. (hereinafter referred to as a temperature drop amount ΔT). In a normal fixing device, in the case of black and white toner, the minimum fixing temperature is 150 ° C. to 160 ° C. Therefore, in this state, defective fixing occurs near the thick portion. Actually, after the set temperature was reached under the same conditions, when the paper carrying the unfixed toner image was fixed by a copying machine "Vivace 550" manufactured by Fuji Xerox Co., Ltd., fixing failure occurred near the thick portion of the roll. .

Next, as described above, an example will be described under the condition of the heat capacity ratio between the central portion and the thick portion of the fixing roll. Instead of forming the thick portion by the uneven thickness processing of the comparative example (FIG. 37) described above, in this example,
A thick portion was similarly formed using a ring of a reinforcing member for increasing the rigidity of the thin-walled cylindrical structure. As a matter of course, the result similar to that of this example can be directly applied to the fixing roll having the thick portion by the uneven thickness processing as described in the comparative example (FIG. 37).

FIG. 39 is a sectional view for explaining the shape of the structure of the fixing roll used in the experiment according to this embodiment.
As shown in FIG. 39, when the roll wall thickness of the thin-walled cylindrical structure 315 used as a fixing roll is T, and the shape parameters of the ring 314 of the reinforcing member are the ring thickness Rt and the ring width Rw, respectively. The numerical values of the parameters are “T = 0.3 mm, 0.5 mm, 1.0 mm” and “(Rt, Rw) = (1.0 mm, 2.0 mm), (1.
0 mm, 4.0 mm), (1.0 mm, 6.0 mm) "were prepared. The other conditions were the same as those of the above-described comparative example (set temperature 180 ° C.), the temperatures in the roll central portion 312 and the thick portion 313 were measured, and the temperature drop ΔT was measured. The experimental result in that case is shown in FIG.
It is shown in 0.

In FIG. 40, the heat capacity C1 (cal / ° C.) of the thick portion and the heat capacity C2 of the roll portion excluding the protrusion are plotted along the horizontal axis.
The heat capacity ratio “C1 / C2” with (cal / ° C.) is taken, and the vertical axis shows the temperature drop amount of the thick portion (the difference between the surface temperature of the roll central portion 312 and the surface temperature of the thick portion 313). There is.

According to the experimental result in this case, as is clear from FIG. 40, the heat capacity ratio "C1 / C2" is "1".
It became clear that the amount of temperature drop in the thick-walled portion was significantly reduced at the boundary of "0". Actually, the heat capacity ratio "C1 /
The ring "(Rt,
Rw) = (1.0 mm, 2.0 mm) ”is arranged on a roll having a roll thickness T of 0.5 mm, and the set temperature is 180 ° C.
As in the comparative example, when a sheet carrying an unfixed toner image was fixed by a copying machine "Vivace 550" manufactured by Fuji Xerox Co., Ltd., a fixing defect near the surface of the thick portion where the ring was arranged was fixed. Did not occur.

Moreover, when the ring member forming the thick portion is made of aluminum, copper, ordinary carbon steel, and carbon alloy steel, the temperature unevenness is examined.
The curve shown in 0 was matched. From this, it was found that the temperature unevenness of the thick portion is more affected by the heat capacity of the thick portion than the thermal conductivity of the thick portion.

Therefore, in the embodiment as the fixing roll of the fixing device in this case, as described above, the fixing roll used in the fixing device is a metal roll having a thin cylindrical structure, which is conventionally used. Compared with the fixing roll, a fixing device with a much shorter warm-up time was realized.

Further, in the embodiment of the present invention, when the metal roll having the thin-walled cylindrical structure is used, the roll having the uneven thickness portion on the inner peripheral surface of the roll is used to prevent the depression in the circumferential direction. In this case, it is possible to prevent the occurrence of temperature unevenness immediately after the power is turned on due to the thick portion, and it is possible to provide a fixing device in which fixing failure does not occur. Further, here, since the structure itself is characteristic, the cost of the fixing device is not increased.

[0094]

As described above, the cylindrical structure used in the fixing device of the present invention can drastically improve the dent strength limit of the thin-walled cylindrical structure that receives an external force at the circumference. Since the manufacturing method is also very easy, it has a very high utility value. Since the thin cylindrical structure is used as the fixing roll of the fixing device, the heat loss due to the supporting member is hardly seen, and thus the warm-up time can be greatly shortened. Since the dent strength limit has been dramatically improved, the load applied between the fixing roll and the pressure roll can be made high, which can greatly contribute to the speedup of the fixing device. When applied to a fixing device,
There is a merit that there is little impact on the volume, weight and cost of the fixing device.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a fixing device by a heat fixing method,

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

FIG. 5 is a sectional view illustrating a fourth example of the structure of a conventional fixing roller;

FIG. 6 is a first diagram illustrating the basic structure of a thin-walled cylindrical structure used in the fixing device of the present invention;

FIG. 7 is a second diagram illustrating the basic structure of the thin-walled cylindrical structure used in the fixing device of the present invention.

FIG. 8 is a diagram showing a first example of the shape of the support member,

FIG. 9 is a diagram showing a second example of the shape of the support member,

FIG. 10 is a diagram showing a third example of the shape of the support member,

FIG. 11 is a diagram illustrating a first example of a method for manufacturing a cylindrical structure according to the present invention,

FIG. 12 is a diagram illustrating a second example of a method for manufacturing a thin-walled cylindrical structure according to the present invention,

FIG. 13 is a first diagram illustrating a third example of a method for manufacturing a thin-walled cylindrical structure according to the present invention,

FIG. 14 is a second diagram illustrating a third example of the method for manufacturing a thin-walled cylindrical structure according to the present invention,

FIG. 15 is a view for explaining a fourth example of the method for manufacturing a thin-walled cylindrical structure according to the present invention,

FIG. 16 is a diagram illustrating a fifth example of a method for manufacturing a thin-walled cylindrical structure according to the present invention,

FIG. 17 is a diagram for explaining the presence of the support member on the outer peripheral surface of the cylindrical structure,

FIG. 18 is a first diagram illustrating a state in which a support member is arranged on a thin-walled cylindrical structure and then the outer diameter of the thin-walled cylindrical structure is machined to a predetermined wall thickness;

FIG. 19 is a diagram illustrating a state in which an outer diameter is processed to further reduce the wall thickness after disposing a support member in a cylindrical structure;

FIG. 20 is a diagram illustrating a roll load application device for a fixing roll;

FIG. 21 is a diagram for explaining a mounting position of a strain gauge for measuring deformation of a thin-walled cylindrical structure,

22 is a diagram showing measurement results at each measurement position in FIG. 21,

FIG. 23 is a view showing a ring-shaped support member used in an experimental example,

FIG. 24 is a diagram showing an example of a modified support member used in an experimental example,

FIG. 25 is a diagram for explaining an experimental example for measuring the degree of deformation in the case where the arrangement positions of a plurality of supporting members are changed in the thin-walled cylindrical structure;

FIG. 26 is a diagram showing a first example of the shape of a deformed supporting member used in an experimental example,

FIG. 27 is a view showing a second example of the shape of the deformed supporting member used in the experimental example,

FIG. 28 is a diagram illustrating a pressing jig used in an experimental example,

FIG. 29 is a diagram illustrating an example of a deformed thin-walled cylindrical structure used in an experimental example,

FIG. 30 is a diagram illustrating an example of a support member press-fitted into the cylindrical structure of FIG. 29;

FIG. 31 is a cross-sectional view illustrating the configuration of a fixing device using the thin-walled cylindrical structure according to the embodiment of the invention.

FIG. 32 is a view for explaining a modified example of the pressure roll in the fixing device of the embodiment of the present invention,

FIG. 33 is a diagram showing an example of a thin-walled cylindrical structure having a thick-walled portion used as a fixing roll in an example of the present invention,

FIG. 34 is an enlarged view showing an enlarged thick portion of an axial cross section of a fixing roll of a fixing device;

Figure 35 shows changes in the temperature rise from the time of start-up of the thin portion roll surface temperature and the thick portion roll surface temperature (at the time of power-on) until the warm-up period Figure,

FIG. 36 is a diagram showing a temperature distribution immediately after warming up in the vicinity of the thick portion of the fixing roll;

FIG. 37 is a view for explaining the shape of a thin-walled cylindrical structure having a thick wall portion as a fixing roll of a fixing device for comparison,

FIG. 38 is a diagram showing experimental results of temperature transitions in the central portion and thick portion of the fixing roll of the comparative example,

FIG. 39 is a cross-sectional view illustrating the shape of the structure of a fixing roll which has been tested,

FIG. 40 is a projection portion heat capacity C1 of the thick portion on the horizontal axis.
It is a figure which shows the example of an experiment which made the ratio of the heat capacity C2 of the roll part except a protrusion part, and made the vertical axis | shaft the thick part temperature drop amount.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inner frame of supporting member of roll, 2 ... Support rod supporting inner frame, 3 ... Roll (sleeve), 4 ... Thermal insulator, 5 ... Coil heater of heating source, 6 ... Offset prevention layer of release layer , 7
... Support shaft 8 ... Roll, 9 ... Thick wall portion, 10 ... Conductive cylindrical member, 11 ... Reinforcing rigid member, 12 ... Contact charging conductive rubber roller, 13 ... Cylindrical outer cylinder, 14 ... Inner core, 15 ... Thin wall Cylindrical structure, 16 ... Supporting member, 17 ... Deformed supporting member, 18 ... Deformed supporting member, 20 ... Thin cylindrical structure, 21-23 ... Supporting member, 24 ... Press-fitting jig, 25-2
7 ... Support jig, 30 ... Heating roller, 31 ... Heater, 32
... Cylindrical core metal, 33 ... Release layer, 40 ... Pressure roller, 41
... Cylindrical cored bar, 42 ... Heat resistant elastic layer, 43 ... Sheet, 4
4 ... Unfixed toner image, 45 ... Cylindrical structure, 46 ... Support member, 50 ... Thin cylindrical structure, 51 ... Support member, 60 ... Cylindrical structure, 61 ... Support member, 70 ... Cylindrical structure, 71 ...
Support member, 70a ... End, 80 ... Thin-walled cylindrical structure, 81
... Support member, 90 ... Cylindrical structure, 91 ... Support member, 20
DESCRIPTION OF SYMBOLS 1 ... Thin-walled cylindrical call, 202 ... Bearing, 203 ... Load application bar, 101 ... Fixing roll, 102 ... Pressure roller, 103 ... Iron core, 104 ... Iron core, 105 ... Support member, 106 ... Heating source, 107 ... Silicon Rubber, 10
8 ... Temperature sensor, 301 ... Roll section, 302 ... Thick section,
303 ... Flat part, 304 ... Projection part, 306 ... Roll part, 309 ... Release layer, 308 ... Projection part, 307 ... Thick part, 310 ... Temperature change of central part, 311 ... Temperature change of thick part 312 ... Roll central part, 313 ... Thick part.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Shoko 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture Fuji Zerox Co., Ltd. (56) References JP-A-57-155571 (JP, A) JP-A-53-129655 ( JP, A) JP 59-30571 (JP, A) JP 4-105720 (JP, A) JP 7-241929 (JP, A) JP 2-277089 (JP, A) Flat 5-59473 (JP, U) Actual Flat 4-65366 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/20

Claims (2)

(57) [Claims] 1. A fixing device in which a plurality of support members are press-fitted inside a thin-walled cylindrical structure, and a part of the outer peripheral surface of the support member is held in pressure contact with the inner surface of the thin-walled cylindrical structure.
In the cylindrical structure used for mounting, the inner diameter of each of the plurality of support members arranged in the thin-walled cylindrical structure is different, and the structure is such that the inner diameters are arranged in descending order. it is cylindrical structure used in the fixing device, which is a reversed crown shape in the axial direction inside diameter. 2. A fixing device in which a plurality of support members are press-fitted inside a thin-walled cylindrical structure, and a part of an outer peripheral surface of the support member is held in pressure contact with the inner surface of the thin-walled cylindrical structure.
In the cylindrical structure used for mounting, the inner diameter of each of the plurality of support members arranged in the thin-walled cylindrical structure is different, and the inner structure is arranged in descending order of inner diameter. A fixing device characterized by being used as a roll.