JP2002126904A - Machining method for thin core bar and machining method for fixing roller core bar for electronic photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin core which is thinner than a conventional one even when an aluminum alloy is used and ensures high rigidity. SOLUTION: This method is for machining a thin core that material pipe 22' the outer surface of which is formed in a recess state to form ribs 26, 25b, and 25a on an inner surface and which has an outer surface cut in a flat state. Cutting is applied divided in a plurality of times on the indentation depths of the ribs 26, 25b, and 25a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a thin metal core and a method for processing a fixing roller core for electrophotography.

[0002]

2. Description of the Related Art As shown in FIG.
The fixing roller 2 used in an electrophotographic image forming apparatus such as a facsimile has a halogen heater 2c in the roller.
And the like, and a nip portion N is formed by being pressed against the pressure roller 3. The fixing roller 2 melts and fixes the toner on the transfer paper P sent to the nip N by the pressure of the nip N and the radiant heat from the heat generating device.

[0003] Conventionally, a fixing roller has been made of an aluminum alloy as a material for securing the heat conductivity and rigidity of the core metal. The general configuration of such a fixing roller is a roller having a cylindrical thin metal core as a base, a powder coating of an outer peripheral surface thereof with a fluorine film or the like, followed by firing and coating a release layer.

In recent years, the thickness of the roller core of the fixing roller has been required to be further reduced in order to improve the thermal conductivity. That is, it is desired to shorten the time required to reach a temperature at which fixing can be performed by reducing the thickness of the roller core metal (rise time of the fixing roller) to promote power saving of a copying machine or the like.

[0005]

However, as described above, the fixing roller needs to have high rigidity in terms of its function, and the thickness of the roller core metal cannot be reduced unnecessarily.

That is, when the thickness of the roller core metal is reduced, as shown in FIG. 8A, the fixing roller 2 is bent or deformed by the pressing force from the pressing roller 3, or as shown in FIG.
As shown in (B), there is a possibility that the pressing force from the pressing roller 3 may cause a deformation such that the outer diameter of the fixing roller 2 is reduced from H1 to H2 and deformed.

[0007] The process limit point at which the thickness can be uniformly reduced by the diamond cutting tool is 0.8 mm in the conventional roller core, and at this thickness, the rise time of the fixing roller is almost the same. 30 seconds is the limit. It was also desired to increase the rise time. Therefore, there has been a demand for simultaneously achieving high rigidity and thinning.

Attempts have been made to use iron or stainless steel as an alternative material to the aluminum alloy material. The thermal conductivity is lower than that of the alloy material, and the uniformity of the temperature distribution is not sufficiently obtained.

Accordingly, an object of the present invention is to provide a method of processing a thin metal core and a method of manufacturing a fixing roller metal core for electrophotography, which are thinner than conventional ones and can secure high rigidity even when an aluminum alloy material is used. Is to do.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, the outer surface of a thin metal core having a concave outer surface for forming a rib on the inner surface is flattened. In the method for processing a thin core metal, the cutting is performed by dividing the rib into a plurality of times with respect to the pressing depth of the rib.

Further, the invention according to claim 2 is characterized in that, in the method for processing a thin cored bar according to claim 1, after the cutting, the finish cutting is performed beyond the indentation depth.

According to a third aspect of the present invention, in the method of processing a thin metal core according to the first aspect, the plurality of cutting intervals are larger than the concave width.

According to a fourth aspect of the present invention, in the thin metal core processing method according to the third aspect, the plurality of cuts are
The cutting is performed with a plurality of blades in which the upstream edge is protruded from the downstream edge, and the edge interval between the plurality of blades is larger than the concave width.

According to a fifth aspect of the present invention, in the method of processing a thin core according to the first aspect, when the rib is formed, both ends of the thin core are supported by drawing in advance. Is characterized in that both ends are subjected to contraction processing.

According to a sixth aspect of the present invention, there is provided a method of processing a thin metal core having a drum-shaped outer peripheral surface, wherein the outer surface of the thin metal core has a concave shape in order to form a rib on the inner surface. In a method of processing a fixing roller core metal for an electrophotographic apparatus, the surface of which is cut flat, the cutting is performed by dividing the rib into a plurality of times with respect to a pressing depth of the rib. It is a processing method.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial view showing a configuration of a roller core of a fixing roller provided in an electrophotographic image forming apparatus such as a copying machine, a facsimile, and a printer as an example of a core metal structure according to the first embodiment of the present invention. It is sectional drawing.

As shown in FIG. 1, the roller mandrel 20 has a main body 22 wider than the paper passing area L and journals 27 and 28 smaller in diameter than the main body 22 formed integrally at both ends thereof.
And The roller core 20 is made of an aluminum alloy.

The main body 22 is formed in a drum shape. The volume of the main body 22 is set to, for example, about 0.08 mm, and is appropriately set according to product performance. The drum volume is defined as the outer diameter D2 outside the paper passing area L and the outer diameter D at the center.
It is a difference D1-D2 from 1.

The main body 22 has a space in which a heating device can be inserted, and has a circular cross section.
Further, on the inner peripheral surface 22b of the main body 22, a group of ribs for increasing rigidity is formed.

The rib group includes a central rib group 25 provided in a central region in the axial direction, and peripheral ribs 26 disposed on both outer sides of the central rib group 25 in the axial direction.

The central rib group 25 includes a central rib 25a located at the center in the axial direction, and end ribs 25b located at both axial ends of the central rib group 25, respectively.
a and the pair of left and right end ribs 25b are equally spaced S2.
Are located in

The peripheral rib 26 has a width S of the central rib group 25 from the axial center of the end rib 25b of the central rib group 25.
1 are provided on the inner peripheral surface 22b at the same distance from each other.

FIG. 2 is an enlarged view of a cross section of the rib, and FIG.
Indicates a semicircular rib, (B) indicates a semicircular rib that is smoothly continuous, (C) indicates an isosceles triangular rib, and (D) indicates a U-shaped rib. , (E) show trapezoidal ribs. Although FIG. 2 shows the case of the center rib 25a as a representative, the same applies to other ribs.

By forming the ribs on the inner peripheral surface of the roller core to increase the rigidity, the thickness of the roller core can be reduced. In particular, the density of the ribs is increased at the axial center of the roller core, which tends to bend and deform when pressure is applied from a pressure roller or the like, so that high strength can be obtained with a small number of ribs. In the present embodiment, even when the thickness of the flat surface of the roller core is reduced to 0.3 mm, the same rigidity as that of the 0.8 mm thick roller core without ribs can be maintained. .

Furthermore, since the density of the ribs is increased at the axial center of the roller core, which tends to bend and deform when pressure is applied from a pressure roller or the like, the volume of the roller core can be reduced, and the heat capacity can be reduced. Can be reduced, the temperature rise by the heat source can be speeded up, and power saving can be achieved.

Further, since the rib arrangement density at the central portion of the roller core is increased, the temperature distribution at which the temperature at the central portion is normally increased can be made uniform. In particular, FIG.
(B), (C), and (E), the rib and the inner peripheral surface 2
By smoothly connecting the flat surface 2b to the flat surface 2b, it is possible to smoothly change the temperature unevenness of the surface when the temperature is increased,
Fixing unevenness can be further reduced.

Further, since the main body portion 22 of the roller core 20 has a drum shape, a circumferential difference can be provided in the axial direction of the fixing roller, whereby the feed amount (linear speed) at the time of fixing by rotation is different. Can be provided. Since a difference can be provided in the feed amount in this way, tension can be applied in both width directions of the transfer paper, thereby preventing the transfer paper from being twisted or wrinkled.

FIG. 3 is a further enlarged view of the cross section of the rib.
As shown in FIG. 3, by forming a minute concave portion 22 c that forms an undulating shape on the outer peripheral surface of the main body portion 22 of the roller core metal 20, when used as a fixing roller, the transfer paper is less likely to be twisted and wrinkled. can do. The depth of the minute concave portion 22c is set, for example, to 1 to 10 μm, preferably 3 μm or less.

FIG. 4 is a longitudinal sectional view of a fixing device provided with a fixing roller having the roller core of FIG. As shown in FIG. 4, the fixing device 1 includes a fixing roller 2 having a surface layer 21 formed on the outer surface of the roller core shown in FIG. 1, a pressing roller 3 for pressing the transfer paper against the fixing roller, and a roller. It comprises a bearing 2a for supporting the journal of the cored bar, a drive gear for driving the fixing roller, and a heat generating device having a halogen heater 2c mounted inside the fixing roller.

In the fixing roller, a surface layer 21 is formed by coating an outer peripheral surface of a roller core with a release layer made of a fluororesin layer. The surface layer 21 is formed to a thickness of, for example, 10 to 30 μm.

FIG. 5 is a partial sectional view showing a roller core of a fixing roller according to a second embodiment of the present invention. As shown in FIG. 5, this roller core differs from the roller core of FIG. 1 in that the center rib group 25 has an intermediate rib 25c between the center rib 25a and the end rib 25b. This is the point that the peripheral rib 26 is composed of the outer peripheral rib 26a and the inner peripheral rib 26b.

In this case, the width S1 of the central rib group 25
S1 between the end rib 25b and the inner peripheral rib 26b
And the width S between the inner peripheral rib 26b and the outer peripheral rib 26a
1 is equal.

As described above, the center rib group 25 includes the center rib 2
5a and the end rib 25b, the center rib 2
One or more intermediate ribs 25c may be formed between 5a and the end rib 25b.

The peripheral ribs 26 may be formed from a plurality of ribs. In this case, the distance between the innermost peripheral rib 26b and the next outer peripheral rib 26a is the width S
It is preferably set to 1.

FIG. 6 is an explanatory view showing the main structure of an image forming apparatus provided with a fixing roller having a roller core as a core metal structure of the present invention. As shown in FIG. 6, the image forming apparatus includes a photosensitive drum 4a on which an electrostatic latent image is formed,
A charging roller 4b for performing charging processing in contact with or in proximity to the photosensitive drum 4a, a developing roller 4e for attaching toner to an electrostatic latent image on the photosensitive drum 4a, and a DC roller for applying a DC voltage to the charging roller 4b. Power supply 4h, photosensitive drum 4
a transfer roller 4f for transferring the toner image on the transfer paper P to the transfer paper P conveyed from the paper supply unit, and a cleaning device 4 for removing and collecting residual toner on the surface of the photosensitive drum 4a.
g, a surface potential meter 4 d for measuring the surface potential of the photosensitive drum 4 a, and the fixing device 1 having the fixing roller 2 and the pressure roller 3. Reference numeral 4c indicates exposure such as laser light or light reflected from a document.

An image forming operation in the image forming apparatus configured as described above will be described. First, a DC voltage is supplied from a power supply 4h to the charging roller 4b in contact with the photosensitive drum 4a, so that the photosensitive drum 4a
Is uniformly charged to a high potential.

Immediately thereafter, the surface of the photosensitive drum 4a is exposed to light 4
When c is applied, the potential of the exposed portion decreases. Since the exposure 4c has a light amount distribution corresponding to the image density, the exposure 4c forms a potential distribution with respect to the recorded image, that is, an electrostatic latent image on the surface of the photosensitive drum 4a.

Next, when the portion where the electrostatic latent image is formed passes through the developing roller 4e, toner adheres according to the level of the potential, and a toner image is formed by visualizing the electrostatic latent image. You. Next, the transfer paper P is conveyed at a predetermined timing to a portion where the toner image is formed, and overlaps the toner image. After the toner image is transferred onto the transfer sheet P by the transfer roller 4f, the transfer sheet P is separated from the photosensitive drum 4a.

Next, the separated transfer paper P is conveyed through a conveyance path, is subjected to heat and pressure fixing by the fixing roller 2 and the pressure roller 3, and is then discharged out of the apparatus. After the completion of the transfer, the surface of the photosensitive drum 4a is
g, and the residual charge is erased by a residual charge erasing means (not shown) to prepare for the next image forming process.

At this time, since a fixing roller having a thinned roller core is used as the fixing roller, the rate of temperature rise of the fixing roller can be improved, the rise time can be greatly reduced, and power saving can be achieved. Can also be achieved. That is, both the warm-up time and the lighting time of the halogen heater can be reduced.

A method of manufacturing an electrophotographic fixing roller using the above-described roller core metal, which is a thin core metal, will be described below.
9A and 9B are diagrams showing a method of manufacturing the fixing roller for electrophotography, wherein FIG. 9A is a drawing process of an end portion (journal) of a raw tube, FIG. 9B is an end surface and chamfering process,
(C) is a cutting step by an end mill, (D) is a reinforcing rib forming step, (E) is a trunk cutting step, (F) is a coating step, and (G) is a tape polishing step. FIG. 11 is a cross-sectional view of the reinforcing rib forming step of FIG.
It is a figure which shows the trunk | drum cutting process of (E).

FIG. 14 is an enlarged view showing a main part of the trunk cutting step of FIG. 9E, wherein FIG. 14A is a view showing a state before the reinforcing ribs are formed, and FIG. 14B is a state after the ribs are formed. (C)
FIG. 4 is a diagram showing a cutting state after rib formation.

In FIG. 14, T1 is the wall thickness of the pipe, F is the flat surface, h is the depth of pushing, LW is the width of the rib, t is the thickness of the metal core,
H is the rib height, C1 is the amount of rough cutting by the first rough cutting tool 47a, C2 is the amount of rough cutting by the second rough cutting tool 47b, and C3 is the amount of finish cutting by the finish cutting tool 48. When the rough cutting amount C2 by the second rough cutting tool 47b is removed, the concave portion 26 'is almost flattened.

As shown in FIG. 9A, first, the raw pipe 2
2 'is held by a collet chuck cc, and drawn using a spinning roller 41 from the end of the raw tube 22' toward the center thereof. As a result, both ends (only one end is shown in the figure) of the raw tube 22 'are formed to have a predetermined diameter, in this embodiment, 30 mm.

At this time, since the drawing process is performed from the end side of the raw tube 22 'toward the center side, that is, since the plastic working is performed from the outside to the inside, the end portion 27 can be thickened. Thereby, the end portion is thickened, so that the strength of the end portion can be improved, and oval cut and D cut described later can be performed. The thickness of the end portion is about 1.5 mm or less with respect to the original thickness of 1.2 mm when the 40 mm tube 22 ′ is drawn to 30 φ.

As a process for reducing the diameter, a swaging process is conventionally known. In this swaging, the end of the straight pipe is reduced in diameter by pushing it into a die (mold). In this swaging process, since molding oil is used, it is necessary to wash by post-processing, and wet processing is performed. In this swaging process, since the body portion is clamped and pushed into the die, it is difficult to obtain the coaxial, and there is a problem that the coaxiality of the reduced diameter portion is deviated.

On the other hand, in the spinning process, since the roller is abutted while the body is being chucked and rotated, necessary coaxiality can be obtained. Further, the processing can be performed by a dry method that does not use a cleaning oil, that is, does not require a cleaning step. Therefore, there is an advantage that it is also good for environmental measures.

Conventionally, there are a swaging process and a spinning process as the diameter reduction process, and the spinning process is mainly called a spatula drawing process and is a process of thinly extending such as a lamp umbrella process. The present inventors considered whether the spinning process could be applied to a fixing roller for increasing the thickness. The spinning roller processing as the processing of the fixing roller was performed on a trial basis, but took a long processing time and was not suitable in terms of cost. This time, other processing can be performed at the same time, so it can be applied to mass production. Further, as described above, it is also excellent in environmental measures. Since the thickness of the core of the fixing roller is thin, it does not take much time as compared with the swaging. In swaging, a special machine called a press is required, but in spinning,
It is possible with a cutting machine (it became possible because of the thinness).

Next, as shown in FIG. 9 (B), a step of processing the end surface (journal) of the end portion (journal) of the raw tube 22 'with the end face cutting tool 43 (uniform length) and a step of chamfering the inner diameter. A step of chamfering the inner diameter (center processing) for holding the raw tube 22 ′ as a work from both ends by the cutting tool 42 is performed.

Next, as shown in FIG. 9C, a part of the end (journal) of the raw tube 22 'is removed by the end mill 44. That is, a so-called oval cut is performed, in which the arc-shaped portion facing the end diameter is removed in parallel with the central axis. Instead of the oval cut, a so-called D-cut, in which only one side is removed, or a so-called U-cut, which is cut out in a U-shape, may be performed. These oval cuts, D cuts, and U-shaped cutouts are formed to prevent the rotation of the drive gear.

As shown in FIG. 11 (A), the end of the raw tube 22 'is journaled in the steps of FIGS. 9 (A) to 9 (C).
7 'and 28' are formed. In addition, this raw tube 22 '
The wall thickness of the portion corresponding to the flat surface F is indicated by the shell thickness T1 as shown in FIG. Next, a vibration absorbing core (not shown) is inserted into the raw tube 22 '.

Next, as shown in FIGS. 9D and 11B, in this reinforcing rib forming step, the spinning roller 4
5 is performed to form a reinforcing rib by spinning. In this step, the central rib 25a is formed last, as described later. Each rib has a pushing depth h and a rib width LW, as shown in FIG. This indentation depth h is formed smaller than the cutting thickness. When the paper passing area of the fixing roller core has a drum shape, the pressing depth h at the time of forming the rib is set to be smaller than the cut thickness in the end region of the drum shape.

Next, as shown in FIG. 9 (E) and FIG. 11 (C), the raw tube 22 'on which the central rib 25a is formed last.
Of the body is first rough-cut with a rough cutting two-piece set tool 47, and then finish-cut with a finish cutting tool 48. In this cutting step, a step of performing rough cutting of the body with two coarse cutting tools (diamond cutting tool for rough cutting) is performed, and then, using the finishing tool (diamond cutting tool for finishing cutting), the journal portions 27 and 28 and the body are cut. A finish cutting step is performed to finish the part. In this step,
As described later, a plurality of stages, in this embodiment, two stages of cutting steps are performed. FIG. 14 shows the cutting state after the rib formation.
It is shown in (C).

As shown in FIG. 11D, a thin, high-strength roller core bar reinforced with ribs is completed. Next, a sand blasting process for roughening the fluororesin coating area is performed by a sand blasting device (not shown).

Next, as shown in FIG. 9F, a coating step of forming a fluororesin layer by firing after coating the fluororesin 50 from the coating nozzle 49 is performed. Next, as shown in FIG. 9 (G), a tape polishing step of polishing the fluororesin-coated surface with a polishing tape 51 is performed to complete the fixing roller.

The step of forming the reinforcing rib shown in FIG. 9D will be described in detail below with reference to FIGS. 10, 12, 13, 15, and 16. 10A and 10B show a main part of a turret lathe used in the reinforcing rib forming step of FIG. 9D and the trunk cutting step of FIG. 9E, wherein FIG. 10A is a front view and FIG. 10B is a side view. . FIG. 10 shows a state in which ribs are formed by spinning.

As shown in FIGS. 10 (A) and 10 (B), the reinforcing rib forming and torso cutting device comprises a turret lathe, and is supported by a turret tool rest 5 which is rotatably supported around a central axis.
2, a spinning roller 45 for forming a reinforcing rib, which is radially attached to the turret tool rest 52, and a base tube 2 which is a thin metal core having a reinforcing rib formed on the inner peripheral surface.
Rough cutting 2-piece set tool 47 for rough cutting the outer peripheral surface of 2 '
And a finishing cutting tool 48 for finishing cutting after rough cutting.
And

As described later, the two-piece rough cutting tool set 47 has a first rough cutting tool 47a and a second rough cutting tool 47b integrally held by a tool holder 47d. Turret tool post 52
Attached to. An air blow nozzle 47c is arranged near the rough cutting tool 47b attached to the turret tool rest 52.

The finishing cutting tool 48 is attached to a turret tool rest 52 via a finishing cutting tool holder 48b. An air blow nozzle 48a is arranged near the finishing cutting tool 48 attached to the turret tool rest 52.

FIG. 12 is a view showing a reference example of the reinforcing rib forming step. When forming the reinforcing ribs, the raw pipe 22 '
Due to the processing force applied to the base tube, the base tube 22 ′, which is a thin metal core, undergoes a bending deformation, but as shown in FIG. 12, when reinforcing ribs are sequentially formed from one end to the other end,
There is a problem that the bellows-like shape is easily deformed, and that the deformation is increased.

FIGS. 13A and 13B show a spinning roller used in the reinforcing rib forming apparatus shown in FIG. 10, wherein FIG. 13A is a side view and FIG. The spinning roller 45 is
As shown in FIG. 13, the pushing width OW corresponding to the rib width
And is attached to the turret tool rest 52 via a spinning roller holder 45a.

As shown in FIG.
The spinning roller 45 is pressed against the rib forming position on the end side at 2 'to form the reinforcing ribs 26 and 25b sequentially. At this time, a ring-shaped groove 26 'which is a concave portion is formed on the outer peripheral surface of the raw tube 22' corresponding to the reinforcing rib 26, and similarly, a concave portion is formed on the outer peripheral surface of the raw tube 22 'corresponding to the reinforcing rib 25b. A ring-shaped groove 25b 'is formed. The order of forming the reinforcing ribs will be described later with reference to FIG.

FIGS. 15A and 15B are views showing the order of forming ribs in the reinforcing rib forming step of FIG. 9D, wherein FIG. 15A shows the beginning of processing, FIG. 15B shows the middle of processing, and FIG. . As shown in FIG. 15, the reinforcing ribs 25a, 25b, 2
A plurality of 6 are formed along the longitudinal direction, and the processing order is such that the rib 25a at the central portion where deflection and deformation are maximum is processed last. Thereby, the deformation becomes uniform in the longitudinal direction by making the central portion where the bending deformation becomes maximum last, and the deformation becomes small. That is, the bellows-like deformation as shown in FIG. 12 is reduced, and the deflection deformation can be reduced.

FIG. 15C shows the order in which the ribs are formed.
In this case, first, the right side 26, then the left side 26, then the right side 25b, then the left side 25b, and finally the center 25a, may be formed alternately from left to right from the outside. Thereby, the left and right bending deformations can be equalized.

FIG. 15C shows the order in which the ribs are formed.
In this case, first, the right 26, then the right 25b, then the left 25b, then the left 26, and finally the center 25a may be sequentially formed.

In the above-mentioned reinforcing rib forming step, the raw tube 22 'as a thin-walled cylindrical tube made of an aluminum alloy is pre-processed to a desired end surface shape, and then chucked and rotated by a processing machine on the basis of both centers. Using a spinning roller 45 as a forming device shown in FIG. 13, the spinning roller 45 is pushed to a predetermined position while being in contact with the outer peripheral surface of the raw tube 22 'during rotation as shown in FIG. 11B. In this spinning drawing, the shape of the pressed portion of the spinning roller 22 ′ is transferred to the outer peripheral surface of the raw tube 22 ′ by pushing the spinning roller 45 back after being pushed to a predetermined position. Also, of the portions in the thickness direction facing the ring-shaped grooves 26 ', 25b', and 25a ', which are concave portions (shapes in the form of a cross section on the axis) transferred to the outer peripheral surface of the raw tube 22'. Reinforcement ribs 26 and 25 which are circumferential convex portions on the peripheral surface
b, 25a are formed. This series of processing is performed on the raw tube 22 '.
By moving the spinning roller 45 in the axial direction, a plurality of uneven portions can be formed in the rotation axis direction of the raw tube 22 '.

FIG. 16 is a view showing a modification in the reinforcing rib forming step of FIG. 9D. As shown in FIG.
In the processing method 5, the backup roller 53 as a backup tool is disposed at a position facing the spinning roller 45. Thereby, the deformation can be suppressed by preventing the bending deformation of the raw tube 22 'due to the processing force during the rib processing. In this embodiment, the backup roller 53 includes two rotating rollers 53a and 53b.

FIG. 17 shows the cutting step of FIG.
19 will be described in detail below. FIG. 17 is FIG.
9B shows a turret lathe used in the reinforcing rib forming step and the trunk cutting step of FIG.
(A) is a front view, (B) is a side view, and (C) is an enlarged view of a cutting tool. Note that FIG. 17 shows a state of rough finishing using a two-piece set tool 47 for rough cutting in a state of a body cutting process using a sintered diamond tool. In addition, as shown in FIG.
Is formed by integrating a first rough finishing tool 47a and a second rough finishing tool 47b into a first rough finishing tool 47a.
A sintered diamond tip 47e is provided at the tip of
A sintered diamond tip 47e is also provided at the tip of the rough finishing tool 47b.

The first rough finishing tool 47a and the second rough finishing tool 47b are arranged such that the tip of the second rough finishing tool 47b projects from the tip of the first rough finishing tool 47a. .2 mm. The distance W between the first rough finishing bit 47a and the second rough finishing bit 47b is the width LW of the reinforcing rib.
(See FIG. 14B.) Thereby, after the deformation by the cutting of the first rough finishing bit 47a converges, the second rough finishing bit 47b can be cut, and the influence of the reaction force by the first rough finishing bit 47a can be prevented.

FIGS. 18A and 18B are views showing one-time cutting of the reference example. FIG. 18A shows an ideal state, and FIG. 18B shows an actual cutting state. FIG. 19A shows a cutting state of a plurality of cutting bits for rough cutting provided in the trunk cutting device according to the cutting method of the present invention, and FIG. 19B shows a single cutting shown in FIG.
It is a figure which shows the cutting resistance of the rib periphery with multiple cutting of (A).

The irregularities (annular groove 26 ′, reinforcing rib 26)
19), the outer peripheral surface of the raw tube 22 'is cut into a plurality of times using a diamond tool or the like, as shown in FIG. By this processing, FIG.
(C) As shown in FIG.
The annular groove is removed to obtain a uniform surface, and the reinforcing ribs such as the annular reinforcing rib 26 remain on the inner peripheral surface.
The rigidity of the raw tube 22 'as a thin cylindrical tube is improved by the reinforcing ribs remaining on the inner peripheral surface, so that a desired thickness can be obtained. Therefore, the thickness can be reduced to t = 0.3 mm with respect to the above-described process thickness limit point (t = 0.8 mm), and the same rigidity as t = 0.8 mm can be maintained. Becomes

The desired fixing roller 2 is manufactured by the above-described processing steps. However, by performing the manufacturing method according to the present invention on the above-described uneven portions formed on the inner and outer peripheral surfaces, the thin wall can be easily and inexpensively manufactured. Is possible. Therefore, since the temperature rise rate can be improved by reducing the thickness of the roller core metal, which is a raw tube as a thin-walled cylindrical tube, the rise time can be shortened.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the case where the number of the central rib groups is three and the case where the number is five are described. Further, in the above embodiment, the case of one peripheral rib and the case of two peripheral ribs have been described, but three or more peripheral ribs may be used. In the above-described embodiment, the case where two cutting tools are connected as rough cutting tools has been described. However, it is a matter of course that three or more cutting tools may be connected to reduce the thickness of one cutting. In the above embodiment, the number of cutting bits for rough cutting is reduced by connecting a plurality of cutting tools.
Although rough machining can be performed with one stroke, machining may be performed with a plurality of strokes one by one. That is, various modifications can be made without departing from the gist of the present invention.

[0074]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A thin tube 22 'which is a thin-walled cylindrical tube to be processed.
Is made of A3000 series AL alloy material, and its size is φ40 × 380L × t1.2. Reinforcing rib 2
In the formation of 6, 25b, 25c, the processing machine is CNC
Using a lathe, the main processing conditions are spindle speed of 600 rpm
m, the indentation amount was φ1.0 mm. Raw tube 22 '
Was chucked at both centers via a rotation center with a center member fixed to a spindle chuck of a CNC lathe as a processing machine and a centering shaft at the other end.

Next, after the main shaft was rotated under the above conditions, a spinning roller 45 shown in FIG. 13 as a molding device was brought into contact with the outer peripheral surface of the raw tube 22 'to form a reinforcing rib.
The feed amount f at this time was 0.1 mm / rev. The main dimensions of the spinning roller 45 used at this time were an outer diameter of φ100 and a tip portion having a width of 1.0 mm.

As a result, the formed concave portions 26 ', 25
b 'and 25c' have a depth of 0.6 to 0.8 mm and a width of 1.0
１．２1.2 mm. The reinforcing ribs 26, 25b, 25c formed on the inner surface also have a depth of 0.3 to 0.5 m.
m, a cross section having a width of 0.8 to 1.8 mm and showing a smooth ridge line.

Next, while the raw tube 22 'is being chucked, the spindle speed is 4500 rpm and the feed amount is 0.1 mm.
The outer diameter was cut using a diamond tool with a nose R0.4 at / rev. As a result, the surface roughness Rz is 3 to
It was about 4 μm.

However, as described above, on the outer peripheral surface corresponding to the vicinity of the convex portion which is the reinforcing rib formed on the inner peripheral surface,
As shown in FIG. 18A, cutting is performed once along the cutting tool trajectory 149 with a single cutting blade 147 until the desired thickness t = 0.4 mm, as shown in FIG. As shown in FIG. 18 (B), a portion without a convex portion has an “escape” 150 inside due to a decrease in rigidity due to a thin wall due to resistance during cutting. Concave in the direction). Therefore, it is not possible to obtain a uniform surface which is a specification as a fixing roller.
As the specifications, generally, a surface roughness Rz of 2 μm or less and a surface waviness Wcm of 3 μm or less are generally required.

Therefore, as shown in FIG. 19 (A), the number of cuts is set stepwise with respect to the tube thickness T1 before cutting, so that the wall thickness before finish cutting (desired thickness t = 0.4) is obtained. By increasing the thickness, the reduction in rigidity is reduced, and the cutting resistance is reduced. In the present invention, the relationship is as shown in FIG. 19B by the convex portions provided on the inner peripheral surface of the base tube 22 '. Actually, a uniform surface can be obtained by setting the finishing allowance to 0.05 to 0.15 mm. In FIG. 19B,
R1 is the cutting force in the case of FIG.
This is the cutting resistance in the case of (B).

By performing the processing according to the present invention described above, it is possible to easily obtain a high-precision thin-walled cylindrical tube having a uniform surface required as a fixing roller. Becomes possible.

Further, an alumina material having an average particle size of 50 μm (nominal particle size # 180) is roughened at a discharge pressure of 2.5 to 4.0 kgf / cm 2 by sand blasting as a fixing roller. As a result, the surface roughness Rz is 9 to 12 μm, and the waveform is also random. Next, a coating member made of a fluororesin or the like is subjected to electrostatic powder coating, and then 3
The film was formed by baking at 80 ° C. The surface layer 21 formed after firing has a thickness of about 20 to 24 μm and a surface roughness Rz of 2.5 to 3 μm. Therefore, the surface layer 2
1 is subjected to tape polishing to obtain a desired surface roughness Rz ≦ 2 μm
Is obtained. If necessary, baking is performed again to smooth the surface of the fluorine film.

[0082]

As described above, according to the present invention,
Even if an aluminum alloy material is used, it is possible to provide a method of processing a thin metal core and a method of processing a fixing roller core metal for electrophotography, which are thinner than before and can secure high rigidity. Further, according to the method of processing the core of the fixing roller for electrophotography, the rise time of the fixing roller can be greatly reduced, and power saving can be achieved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a configuration of a roller core of a fixing roller included in an electrophotographic image forming apparatus as an example of a core metal structure according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a cross section of a rib, (A) shows a semicircular rib, (B) shows a semicircular rib that is smoothly continuous, and (C) shows an isosceles triangular shape. The ribs of
(D) shows a U-shaped rib, and (E) shows a trapezoidal rib.

FIG. 3 is a further enlarged view of a cross section of a rib.

FIG. 4 is a longitudinal sectional view of a fixing device provided with a fixing roller having the roller core of FIG. 1;

FIG. 5 is a partial sectional view showing a roller core of a fixing roller according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a main configuration of an image forming apparatus including a fixing roller having a roller core as a core metal structure of the present invention.

FIG. 7 is a diagram illustrating a fixing roller used in an electrophotographic image forming apparatus.

FIG. 8 is a diagram showing a technical problem of a thin fixing roller;
(A) shows the case of the bending deformation, and (B) shows the case of the crushing deformation.

9A and 9B are diagrams illustrating a method of manufacturing a fixing roller for electrophotography, wherein FIG. 9A illustrates a drawing process of an end portion (journal) of a raw tube, and FIG. 9B illustrates an end surface and a chamfering process. Yes, (C) is a cutting process using an end mill,
(D) is a reinforcing rib forming step, (E) is a trunk cutting step,
(F) is a coating step, and (G) is a tape polishing step.

FIG. 10 shows a reinforcing rib forming step of FIG. 9D and FIG.
(E) shows the main part of the turret lathe used in the trunk cutting step, (A) is a front view, (B) is a side view.

11 is a view showing a reinforcing rib forming step in FIG. 9D and a trunk cutting step in FIG. 9E.

FIG. 12 is a diagram showing a reference example of a reinforcing rib forming step.

13A and 13B show a spinning roller used in the reinforcing rib forming apparatus shown in FIG. 10, wherein FIG. 13A is a side view and FIG.

FIG. 14 is an enlarged view of a main part of the trunk cutting step of FIG. 9 (E), and FIG. 14 (A) is a view showing a state before a reinforcing rib is formed, and FIG.
FIG. 4 is a diagram showing a state after rib formation, and FIG. 4C is a diagram showing a cutting state after rib formation.

15A and 15B are diagrams showing the order of forming ribs in the reinforcing rib forming step of FIG. 9D, wherein FIG. 15A shows the beginning of processing, FIG. 15B shows the middle of processing, and FIG.

FIG. 16 is a view showing a modification in the reinforcing rib forming step of FIG. 9 (D).

17 (A) and FIG. 9 (B).
(E) shows a turret lathe used in the body cutting step,
(A) is a front view, (B) is a side view, and (C) is an enlarged view of a cutting tool.

FIGS. 18A and 18B are views showing a single cutting of the reference example, where FIG. 18A shows an ideal state and FIG. 18B shows an actual cutting state.

FIG. 19A shows a cutting state of a multi-blade rough cutting tool provided in a trunk cutting device according to the cutting method of the present invention,
(B) is a diagram showing the cutting resistance around the rib between the single cutting in FIG. 18 (B) and the multiple cutting in FIG. 19 (A).

[Explanation of symbols]

 2 Fixing Roller 20 Roller Core (Core Metal Structure) 22 Main Body 22b Inner Peripheral Surface 22c Small Concave 25 Central Rib Group 25a Central Rib 25b End Rib 26 Peripheral Rib S1 Width (Pitch) S2 Width (Pitch)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03G 15/20 103 G03G 15/20 103 // B21D 51/16 B21D 51/16 Z (72) Inventor Toshio Kojima Tokyo 1-3-6 Nakamagome, Ota-ku Ricoh Co., Ltd. F-term (reference) 2H033 AA31 BB03 BB13 BB26 3C045 CA07 DA07 3J103 AA02 AA13 AA24 AA36 AA51 AA81 BA05 EA01 EA03 FA02 FA19 GA02 GA57 GA58 GA60 HA04 HA05 HA37

Claims (6)

[Claims] 1. A method of processing a thin metal core in which an outer surface of a thin metal core having a concave shape to form a rib on an inner surface is flatly cut, and wherein a pressing depth of the rib is determined. A method for processing a thin cored bar, wherein the cutting is performed in a plurality of times. 2. The method for processing a thin cored bar according to claim 1, further comprising, after the cutting, finishing the cutting beyond the indentation depth. 3. The method according to claim 1, wherein the plurality of cutting intervals are larger than the width of the concave shape. 4. The method according to claim 1, wherein the cutting is performed a plurality of times with a plurality of blades having an upstream edge protruding from a downstream edge, and a blade interval between the plurality of blades is larger than the concave width. The method of processing a thin cored bar according to claim 3. 5. The thin core according to claim 1, wherein when the ribs are formed, both ends of the thin core are contracted in advance by drawing in order to support both ends of the thin core. Gold processing method. 6. A method for processing a thin metal core having a drum-shaped outer peripheral surface, wherein the outer surface of the thin metal core having a concave shape for forming a rib on the inner surface is flattened. A method of processing a fixing roller core metal for an electrophotographic apparatus, comprising: cutting the fixing roller core metal for an electrophotographic apparatus a plurality of times with respect to a pressing depth of the rib.