JP3968213B2 - Processing method for thin cored bar, processing method for fixing roller cored bar for electrophotographic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a thin metal core such as an electrophotographic photoreceptor, a fixing roller, and a developing sleeve.
[0002]
[Prior art]
As shown in FIG. 7, a fixing roller 2 used in an electrophotographic image forming apparatus such as a copying machine, a printer, or a facsimile includes a heat generating device such as a halogen heater 2c in the roller, and a pressure roller. 3 is pressed to form a nip portion N. Such a fixing roller 2 melts and fixes the toner on the transfer paper P sent to the nip portion N by the pressure of the nip portion N and the radiant heat from the heat generating device.
[0003]
Conventionally, an aluminum alloy is used as a material for the fixing roller in order to ensure thermal conductivity and rigidity. The general structure of such a fixing roller is such that a cylindrical and thin roller metal core is used as a base, and a coating film is coated on the outer peripheral surface by powder coating with a fluorine film or the like, followed by baking.
[0004]
In recent years, the core metal of the fixing roller has been required to be further thinned in order to improve thermal conductivity. That is, it is desired to shorten the time required to reach a fixing temperature (the rise time of the fixing roller) by reducing the thickness of the roller metal core and to promote power saving in a copying machine or the like.
[0005]
[Problems to be solved by the invention]
However, as described above, the fixing roller is required to have high rigidity in terms of its function, and the thickness of the roller core cannot be reduced unnecessarily.
[0006]
That is, when the roller core is thinned, as shown in FIG. 8A, the fixing roller 2 is deformed by the pressing force from the pressure roller 3, or as shown in FIG. 8B. As described above, the pressing force from the pressure roller 3 may cause a problem that the outer diameter of the fixing roller 2 is deformed by being reduced from H1 to H2.
[0007]
Further, the process limit point at which the wall thickness can be uniformly reduced with a diamond tool is 0.8 mm with the conventional roller mandrel. With this wall thickness, the rise time of the fixing roller is approximately 30 seconds. There is a limit. It has also been desired to increase the rise time. Therefore, it has been desired to achieve both high rigidity and thinning at the same time.
[0008]
Attempts have also been made to use iron and stainless steel materials as alternatives to aluminum alloy materials, but they do not meet the manufacturing cost due to rust prevention measures, workability problems, etc. In comparison, the thermal conductivity is low, and the uniformity of temperature distribution is not sufficiently obtained.
[0009]
Accordingly, an object of the present invention is to provide a method for processing a thin core metal bar and a method for processing an electrophotographic fixing roller core metal that can secure a high rigidity even if an aluminum alloy material is used. is there.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is characterized in that, for example, by rotating the thin metal core while supporting both ends of a hollow cylindrical metal core having an outer diameter φD shown in FIG. In the processing method of forming the rib on the inner surface of the thin metal core by pressing the pressing member on the surface,
Relative speed between the thin cored bar and the cutting means for cutting so that the cutting resistance becomes close to a constant when the recess formed by the pressing member is removed by cutting on the outer peripheral surface of the thin cored bar. Is a method for processing a thin metal core.
[0011]
According to a second aspect of the present invention, in the thin cored bar processing method according to the first aspect of the present invention, the adjustment of the relative speed is performed by changing an axial feed speed of the cutting means relative to the thin cored bar to a portion without a rib. The outer peripheral surface portion corresponding to the portion having the rib is set so as to be faster than the outer peripheral surface portion corresponding to.
[0012]
According to a third aspect of the present invention, in the thin cored bar processing method according to the first aspect, the relative speed is adjusted by adjusting the rotational speed of the main shaft holding the thin cored bar with respect to the cutting means, and the pressing member The outer peripheral surface portion corresponding to the portion with the rib is set to be lower than the outer peripheral surface portion corresponding to the portion without the rib.
[0013]
As the definition of these relative speeds, the feed speed FF in the axial direction of the cutting means and the rotational speed N of the main shaft holding the thin metal core are indicated by a cutting feed amount FL in the cutting process, and the relationship is expressed by the following equation: Defined in (1).
FF [mm / min] = FL [mm / rev] × N [rpm] (1)
Similarly, in the cutting process, the rotational speed, which is the cutting speed, can be defined with respect to the rotational speed N of the main shaft as V, and the rotational speed can be defined by the following equation (2).
V [mm / min] = (π × φD [mm] × N [rpm]) / 1000 (2)
The above-mentioned relational expressions, (1), and (2) show the above-mentioned relative speeds in terms of feed speed and rotational speed, respectively. Sometimes expressed in numbers.
[0014]
According to a fourth aspect of the present invention, there is provided a method for processing a thin cored bar whose outer peripheral surface is a drum shape, wherein the outer surface of the thin cored bar having a recess formed on the outer surface in order to form a rib on the inner surface is flattened. In the processing method of the fixing roller core bar for the electrophotographic apparatus to be cut into
A fixing roller for an electrophotographic apparatus, wherein, when the recess is removed by cutting, a relative speed between the thin cored bar and the cutting means for cutting is adjusted so that a cutting resistance becomes almost constant. This is a method of processing a cored bar.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a part of the configuration of a roller core of a fixing roller provided in an electrophotographic image forming apparatus such as a copying machine, a facsimile, or a printer as an example of a core metal structure according to the first embodiment of the present invention. It is sectional drawing.
[0016]
As shown in FIG. 1, the roller metal core 20 includes a main body portion 22 wider than the sheet passing region L, and journal portions 27 and 28 having a smaller diameter than the main body portion 22 formed integrally at both ends thereof. . The roller core 20 is made of an aluminum alloy.
[0017]
The main body 22 is formed in a drum shape. The drum amount of the main body 22 is set to about 0.08 mm, for example, and is appropriately set depending on the product performance. The drum volume is a difference D1-D2 between the outer diameter D2 outside the paper passing area L and the outer diameter D1 at the center.
[0018]
The main body 22 has a space in which a heat generating device can be inserted, and has a circular cross section. Further, a rib group for increasing rigidity is formed on the inner peripheral surface 22b of the main body portion 22.
[0019]
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 in the axial direction of the central rib group 25.
[0020]
The central rib group 25 includes a central rib 25a positioned at the center in the axial direction and end ribs 25b positioned at both axial ends of the central rib group 25. The central rib 25a and a pair of left and right end ribs 25b Are arranged at equal intervals S2.
[0021]
The peripheral ribs 26 are provided on the inner peripheral surface 22b at an equal distance from the center S in the axial direction of the end ribs 25b of the central rib group 25 and spaced apart from the width S1 of the central rib group 25, respectively.
[0022]
2A and 2B are enlarged views of a rib cross section, where FIG. 2A shows a semicircular rib, FIG. 2B shows a smoothly continuous semicircular rib, and FIG. 2C is an isosceles triangle. (D) shows a U-shaped rib, and (E) shows a trapezoidal rib. In addition, although the case of the center rib 25a is shown as a representative in FIG. 2, the other ribs are the same.
[0023]
Thus, by forming a rib on the inner peripheral surface of the roller metal core and increasing the rigidity, the roller metal core can be thinned. In particular, since the arrangement density of the ribs is increased in the central portion in the axial direction of the roller metal core which is easily deformed when pressure is applied from a pressure roller or the like, high strength can be obtained with a small number of ribs. In this embodiment, even if the thickness of the flat surface of the roller cored bar is reduced to 0.3 mm, the rigidity comparable to that of the 0.8 mm thick roller cored bar without ribs could be maintained. .
[0024]
Furthermore, since the arrangement density of the ribs is increased in the central portion in the axial direction of the roller metal core that is easily deformed when pressure is applied from a pressure roller or the like, the volume of the roller metal core can be reduced, and the heat capacity can be reduced. Therefore, the temperature rise by the heat source can be speeded up, and power saving can be achieved.
[0025]
In addition, since the rib arrangement density in the central portion of the roller core is increased, it is possible to achieve a uniform temperature distribution that normally increases the temperature in the central portion.
In particular, as shown in FIGS. 2 (B), (C), and (E), by smoothly connecting the rib and the flat surface of the inner peripheral surface 22b, it is possible to smoothly change the temperature unevenness of the surface at the time of temperature increase. And fixing unevenness can be further reduced.
[0026]
Further, since the main body portion 22 of the roller metal core 20 has a drum shape, it is possible to provide a circumferential difference in the axial direction of the fixing roller, thereby providing a difference in the feed amount (linear speed) during fixing by rotation. Can do. 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 twisting and wrinkling of the transfer paper.
[0027]
FIG. 3 is a further enlarged view of the rib cross section.
As shown in FIG. 3, by forming a minute concave portion 22c that forms a wavy 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 reduced in wrinkles, wrinkles, and the like. can do. The depth of the minute recess 22c is set to 1 to 10 μm, preferably 3 μm or less, for example.
[0028]
FIG. 4 is a longitudinal sectional view of a fixing device including a fixing roller having the roller cored bar of FIG.
As shown in FIG. 4, the fixing device 1 includes a fixing roller 2 in which a surface layer 21 is formed on the outer surface of the roller core shown in FIG. 1, a pressure roller 3 that presses the transfer paper to the fixing roller, a roller A bearing 2a that pivotally supports the journal portion of the core metal, a drive gear that drives the fixing roller, and a heat generation device that includes a halogen heater 2c mounted inside the fixing roller are configured.
[0029]
The fixing roller has a surface layer 21 formed by coating a release layer made of a fluororesin layer on the outer peripheral surface of a roller core. The surface layer 21 is formed with a film thickness of 10 to 30 μm, for example.
[0030]
FIG. 5 is a partial cross-sectional view showing a roller metal core of a fixing roller according to the second embodiment of the present invention.
As shown in FIG. 5, the roller cored bar is different from the roller cored bar of FIG. 1 in that the central rib group 25 is provided with an intermediate rib 25c between the central rib 25a and the end rib 25b. The peripheral rib 26 is composed of an outer peripheral rib 26a and an inner peripheral rib 26b.
[0031]
In this case, the width S1 of the central rib group 25, the width S1 of the end rib 25b and the inner peripheral rib 26b, and the width S1 of the inner peripheral rib 26b and the outer peripheral rib 26a are equal.
[0032]
As described above, if the central rib group 25 includes the center rib 25a and the end rib 25b, one or more intermediate ribs 25c are formed between the center rib 25a and the end rib 25b. May be.
[0033]
Moreover, you may make it form the peripheral rib 26 from multiple pieces. In this case, the distance between the innermost peripheral rib 26b and the next outer peripheral rib 26a is preferably set to the width S1.
[0034]
FIG. 6 is an explanatory view 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.
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 that performs charging processing in contact with or in proximity to the photosensitive drum 4a, and a photosensitive drum. A developing roller 4e for attaching toner to the electrostatic latent image 4a, a power source 4h for applying a DC voltage to the charging roller 4b, and a transfer paper on which the toner image on the photosensitive drum 4a has been conveyed from the paper feeding unit. A transfer roller 4f for transferring to P, a cleaning device 4g for removing and collecting residual toner on the surface of the photosensitive drum 4a, a surface potential meter 4d for measuring the surface potential of the photosensitive drum 4a, a fixing roller 2 and an additional roller. And a fixing device 1 having a pressure roller 3. Reference numeral 4c indicates exposure of laser light or reflected light of the original.
[0035]
An image forming operation in the image forming apparatus configured as described above will be described. First, the surface of the photosensitive drum 4a is uniformly charged at a high potential by supplying a DC voltage from the power source 4h to the charging roller 4b in contact with the photosensitive drum 4a.
[0036]
Immediately after that, when the surface of the photosensitive drum 4a is exposed 4c, the potential of the exposed portion decreases. Since the exposure 4c has a light amount distribution corresponding to the density of the image, a potential distribution with respect to the recorded image, that is, an electrostatic latent image is formed on the surface of the photosensitive drum 4a by the exposure 4c.
[0037]
Next, when the portion where the electrostatic latent image is formed passes through the developing roller 4e, the toner adheres according to the level of the potential, and a toner image that visualizes the electrostatic latent image is formed.
Next, the transfer paper P is conveyed at a predetermined timing to the portion where the toner image is formed, and overlaps the toner image. After the toner image is transferred to the transfer paper P by the transfer roller 4f, the transfer paper P is separated from the photosensitive drum 4a.
[0038]
Next, the separated transfer paper P is transported through a transport path, fixed by heat and pressure by the fixing roller 2 and the pressure roller 3, and then discharged outside the apparatus. After the transfer, the surface of the photosensitive drum 4a is cleaned by the cleaning device 4g, and the residual charge is erased by a residual charge erasing unit (not shown) to prepare for the next image forming process.
[0039]
At this time, a fixing roller having a thin roller core is used as the fixing roller, so that the temperature increase rate of the fixing roller can be improved, the rise time can be greatly shortened, and power saving can also be achieved. can do. That is, both the warm-up time and the lighting time of the halogen heater can be shortened.
[0040]
A method for manufacturing an electrophotographic fixing roller using the roller cored bar as described above will be described below.
9A and 9B are diagrams showing a method for manufacturing an electrophotographic fixing roller, in which FIG. 9A is a drawing process of an end portion (journal) of a raw tube, FIG. 9B is an end face and chamfering process, ) Is a cutting process by an end mill, (D) is a reinforcing rib forming process, (E) is a body cutting process, (F) is a coating process, and (G) is a tape polishing process. Moreover, FIG. 11 is a figure which shows the reinforcement rib formation process of FIG.9 (D), and the trunk | drum cutting process of FIG.9 (E).
[0041]
FIG. 14 is an enlarged view of the main part of the body cutting process of FIG. 9 (E), (A) is a diagram showing a state before the formation of a reinforcing rib, and (B) is a diagram showing a state after the rib is formed. (C) is a figure which shows the cutting state after rib formation.
[0042]
In FIG. 14, T1 is a tube thickness, FT is a flat surface, h is an indentation depth, LW is a rib width, t is a core metal thickness, H is a rib height, and C1 is a cutting tool as a cutting means. A rough cutting amount by the rough cutting tool 47, C2 is a finishing cutting amount by the finishing cutting tool 48. When the rough cutting amount C2 by the rough cutting tool 47 is removed, the concave portion 26 'is almost flattened.
[0043]
As shown in FIG. 9A, first, the raw tube 22 ′ is held by a collet chuck cc, and drawn by using a spinning roller 41 from the end side of the raw tube 22 ′ toward the center. As a result, both end portions (only one end portion is shown in the figure) of the raw tube 22 'are formed to have a predetermined diameter, in this embodiment, 30φ.
[0044]
At this time, since drawing is performed from the end side to the center side of the raw tube 22 ', that is, plastic processing is performed from the outside to the inside, the end 27 can be increased in thickness. Thereby, since an edge part is thickened, the strength improvement of an edge part and the oval cut and D cut mentioned later are attained. The thickness of the end portion is about 1.5 mm less than the original thickness of 1.2 mm when the 40 φ raw tube 22 ′ is drawn to 30 φ.
[0045]
Conventionally, swaging is known as a process for reducing the diameter. In this swaging process, the end of the straight pipe is reduced in diameter by pressing it into a die (die). In this swaging process, since molding oil is used, it is necessary to clean it by post-processing, which is a wet process.
In this swaging process, since the body part is clamped and pushed into the die, there is a problem that it is difficult to put out the same axis, and the coaxiality of the reduced diameter part is out of order.
[0046]
On the other hand, in the spinning process, the roller is abutted while chucking and rotating the body portion, so that the necessary coaxiality can be obtained. Furthermore, it can be processed in a dry process that does not use cleaning oil, that is, does not require a cleaning process. For this reason, there is an advantage that it is good for environmental measures.
[0047]
Conventionally, as diameter reduction processing, there are swaging processing and spinning processing, but in the spinning processing, a spatula drawing processing is mainly performed, such as a processing of a lamp umbrella and the like, and a thin extension processing. The inventors of the present invention have considered whether it can be applied to a fixing roller that increases the thickness of spinning. Spinning roller processing as a fixing roller processing was carried out on a trial basis, but it took processing time and was not cost effective. This time, other processing can be done at the same time, so it could be applied to mass production. Furthermore, as described above, it is excellent in environmental measures. Since the core of the fixing roller is thin, it does not take much time compared to swaging. The swaging process requires a special machine called a press, but the spinning process is possible with a cutting machine (because it is thin).
[0048]
Next, as shown in FIG. 9B, the end face (journal) end face of the raw tube 22 ′ is processed (equalized in length) by the end face processing tool 43, and the inner diameter chamfering tool 42 is used. A process of chamfering the inner diameter (centering) for pressing the raw tube 22 'as a workpiece from both ends is performed.
[0049]
Next, as shown in FIG. 9C, the end mill 44 removes a part of the end portion (journal) of the raw tube 22 ′. That is, a so-called oval cut is performed in which arc-shaped portions opposed on the diameter of the end portion are removed in parallel with the central axis. Further, instead of the oval cut, a so-called D-cut that removes only one side or a so-called U-cut that is cut into a U shape may be performed. These oval cuts, D cuts, and U-shaped cutouts are formed to prevent the drive gear from rotating.
[0050]
As shown in FIG. 11A, journal portions 27 'and 28' are formed at the end of the raw tube 22 'by the steps of FIGS. 9A to 9C. The thickness of the portion corresponding to the flat surface FT of the tube 22 'is indicated by the tube thickness T1 as shown in FIG.
Next, a vibration absorbing core (not shown) is inserted into the raw tube 22 '.
[0051]
Next, as shown in FIGS. 9D and 11B, in this reinforcing rib forming step, a step of forming reinforcing ribs by spinning using the spinning roller 45 is performed. In this step, as will be described later, the central rib 25a is formed last. Each rib has an indentation depth h and a rib width LW, as shown in FIG. This indentation depth h is smaller than the cutting thickness. Further, when the sheet passing area of the fixing roller core has a drum shape, the pushing depth h at the time of rib formation is set smaller than the cutting thickness for the end region of the drum shape.
[0052]
Next, as shown in FIGS. 9 (E) and 11 (C), the outer surface of the body portion of the raw tube 22 ′, in which the central rib 25a is finally formed, is first roughly cut with a rough cutting tool 47. Thereafter, finish cutting is performed with a finish cutting tool 48. In this cutting step, a rough cutting process is performed on the barrel portion with a rough cutting bit (rough cutting diamond bit), and then the journal portions 27 and 28 and the barrel portion are processed with a finishing bit (finish cutting diamond bit). A finish cutting process is performed to finish the process. The cutting state after this rib formation is shown in FIG.
[0053]
As shown in FIG. 11D, a high strength roller core bar reinforced with thin walls and ribs is completed.
Next, a sand blasting process for roughening the fluororesin coating area is performed by a sand blasting apparatus (not shown).
[0054]
Next, as shown in FIG. 9F, a coating process is performed in which a fluororesin layer is formed by baking after coating the fluororesin 50 from the coating nozzle 49.
Next, as shown in FIG. 9G, a tape polishing process for polishing the fluororesin-coated surface with the polishing tape 51 is performed to complete the fixing roller.
[0055]
The reinforcing rib forming step in FIG. 9D will be described in detail below based on FIGS. 10, 12, 13, 15, and 16.
10A and 10B show the main part of the turret lathe used in the reinforcing rib forming step in FIG. 9D and the trunk cutting step in FIG. 9E, where FIG. 10A is a front view and FIG. 10B is a side view. . In addition, in FIG. 10, the state which forms the rib by spinning process is shown.
[0056]
As shown in FIGS. 10 (A) and 10 (B), the reinforcing rib forming and body cutting device is composed of a turret lathe, and is supported so as to be rotatable around the center axis, and a turret tool post. A roughing cutting tool for roughly cutting the outer peripheral surface of the base tube 22 ', which is a thin cored bar having a reinforcing rib formed on the inner peripheral surface and a spinning roller 45 for reinforcing rib formation, which is radially attached to 52 47 and a finish cutting tool 48 for finish cutting after rough cutting.
[0057]
The rough cutting tool 47 is held by a tool holder 47d, and is attached to the turret tool post 52 by the tool holder 47d. An air blow nozzle 47c is disposed in the vicinity of the cutting coarse cutting tool 47b attached to the turret tool post 52.
[0058]
The finish cutting tool 48 is attached to the turret tool post 52 via a finish cutting tool holder 48b. An air blow nozzle 48 a is disposed in the vicinity of the finishing cutting tool 48 attached to the turret tool post 52.
[0059]
FIG. 12 is a view showing a reference example of the reinforcing rib forming step.
The processing force applied to the tube 22 'from the roller tool when the reinforcing rib is formed causes the thin tube 22' to bend and deform, but as shown in FIG. 12, from one end side to the other end side. If the reinforcing ribs are sequentially formed, it becomes easy to deform into a bellows shape, and there is a problem that the deformation of the contact increases.
[0060]
FIG. 13 shows a spinning roller used in the reinforcing rib forming apparatus of FIG. 10, wherein (A) is a side view and (B) is a partially sectional perspective view.
As shown in FIG. 13, the spinning roller 45 has a pushing width OW corresponding to the rib width, and is attached to the turret tool post 52 via a spinning roller holder 45a.
[0061]
As shown in FIG. 11B, the reinforcing ribs 26 and 25b are sequentially formed by pressing the spinning roller 45 at the rib forming position on the end side of the raw tube 22 '. At this time, a ring-shaped groove 26 'which is a recess 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.
[0062]
FIGS. 15A and 15B are diagrams showing the order of rib formation in the reinforcing rib forming step of FIG. 9D, wherein FIG. 15A shows the first processing, FIG. 15B shows the middle of processing, and FIG. 15C shows the last processing.
As shown in FIG. 15, a plurality of reinforcing ribs 25a, 25b, and 26 are formed along the longitudinal direction. As the processing order, the rib 25a at the central portion that is the largest in deformation 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.
[0063]
In addition, as shown in FIG. 15C, the ribs are formed on the right side, the left side 26, the right side 25b, the left side 25b, and finally the center 25a. You may make it form alternately one after another. Thereby, the left and right deflection deformation can be equalized.
[0064]
In addition, as shown in FIG. 15C, the ribs are formed in the order of 26 on the right side, then 25b on the right side, then 25b on the left side, then 26 on the left side, and finally 25a on the center. You may do it.
[0065]
In the above-described reinforcing rib forming step, the raw tube 22 'as a thin cylindrical tube made of an aluminum alloy is pretreated to a desired end face shape, and then chucked and rotated by the processing machine with reference to both centers. Using the spinning roller 45 as the molding apparatus shown in FIG. 13, the spinning roller 45 is pushed into 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 pushing portion of the spinning roller 22 'is transferred to the outer peripheral surface of the raw tube 22' by returning the spinning roller 45 after pushing to a predetermined position. Of the portions facing the ring-shaped grooves 26 ′, 25 b ′, 25 a ′, which are concave portions transferred to the outer peripheral surface of the raw tube 22 ′ (showing the shape of the cross section on the axis) in the thickness direction. Reinforcing ribs 26, 25b and 25a, which are circumferential convex portions, are formed on the peripheral surface. By moving the spinning roller 45 in the axial direction of the raw tube 22 ′ in this series of processing, a plurality of concave and convex portions can be formed in the direction of the rotation center axis of the raw tube 22 ′.
[0066]
FIG. 16 is a view showing a modification in the reinforcing rib forming step of FIG.
As shown in FIG. 16, in the processing method of FIG. 15, a backup roller 53 as a backup tool is disposed at a position facing the spinning roller 45. Thereby, a deformation | transformation can be suppressed by preventing the bending deformation | transformation of element | tube 22 'by the processing force at the time of rib processing. In this embodiment, the backup roller 53 includes two follower rollers 53a and 53b.
[0067]
The cutting process of FIG. 9 (E) will be described in detail below with reference to FIGS. FIG. 17 shows the turret lathe used in the reinforcing rib forming step of FIG. 9D and the barrel cutting step of FIG. 9E in a state rotated 180 degrees, (A) is a front view, and (B) is a side view. , (C) is an enlarged view of bytes. Note that FIG. 17 shows a state of rough finishing using a rough cutting bit 47 in a state of cutting a body portion with a sintered diamond bit.
[0068]
18A and 18B are diagrams showing one-time cutting of a reference example, where FIG. 18A shows an ideal state and FIG. 18B shows an actual cutting state.
FIG. 19A shows the cutting state of the cutting tool for rough cutting according to the cutting method of the present invention, and FIG. 19B shows the cutting around the rib between the single cutting of the reference example of FIG. 18B and the cutting according to the present invention. It is a figure which shows resistance.
[0069]
After forming the uneven portions (annular grooves 26 ', reinforcing ribs 26, etc.), the outer peripheral surface of the raw tube 22' is cut using a diamond tool or the like as shown in FIG. By performing this processing as described later, as shown in FIG. 14C, the annular groove 26 'as a concave portion on the outer peripheral surface is removed to obtain a substantially uniform surface, and an annular reinforcing rib is formed on the inner peripheral surface. 26 will remain. The reinforcing ribs remaining on the inner peripheral surface improve the rigidity of the raw tube 22 'as a thin cylindrical tube, thereby making it possible to obtain a desired thickness. Therefore, it is possible to reduce the thickness to t = 0.3mm with respect to the above-mentioned process thickness limit point (t = 0.8mm), and it is possible to maintain the same rigidity as t = 0.8mm. It becomes.
[0070]
Next, a cutting method capable of preventing swell due to escape during processing will be described.
First, as shown in FIG. 19B, since the rigidity is different between the place where the rib is present and the place where the rib is not present, the cutting resistance is different between the place where the rib is present and the place where the rib is not present as shown by the curve R2.
[0071]
Therefore, by adjusting the relative speed between the raw tube 22 'and the rough cutting tool, that is, the spindle rotational speed and the feed amount, based on the change in the cutting resistance, the swell after cutting due to the relief of the less rigid portion can be increased. To prevent.
[0072]
FIG. 20 is a diagram showing the spindle speed according to an embodiment of the processing method of the present invention. The horizontal axis is the axial position in the inner rib forming portion of the thin metal core, and the vertical axis is the ratio of the main shaft rotation speed [NL / N]. However, NL [rev] is the main shaft rotational speed of the portion corresponding to the rib that is the convex portion of the inner peripheral surface, and N [rev] is the main shaft rotational speed.
[0073]
As shown in FIG. 20, the main shaft rotation speed NL [rev] at a portion facing the rib that is the convex portion on the inner peripheral surface with respect to the main shaft rotation speed N [rev] from the relationship between the core metal rigidity and the cutting resistance. By reducing the cutting force, it is possible to reduce the cutting resistance and to prevent the bulge after cutting by reducing the relief of the portion having weak rigidity.
[0074]
FIG. 21 is a diagram showing a cutting feed amount according to an embodiment of the processing method of the present invention. The horizontal axis represents the position in the axial direction of the inner rib forming portion of the thin metal core, and the vertical axis represents the feed rate ratio [FL / F]. However, FL [mm / rev] is a feed amount of a portion corresponding to a rib which is a convex portion of the inner peripheral surface, and F [mm / rev] is a predetermined cutting feed amount corresponding to a flat portion of the inner peripheral surface. is there.
[0075]
As shown in FIG. 21, the cutting feed amount is a predetermined feed amount F [mm / rev], and the cutting feed amount FL [mm / rev] at a portion facing the rib that is a convex portion on the inner peripheral surface. By increasing the cutting force, it is possible to reduce the cutting resistance and to prevent the bulge after cutting by reducing the relief of the portion having weak rigidity.
[0076]
FIG. 22 is a schematic view showing an example of a processing apparatus used in the processing method of the present invention.
As shown in FIG. 22, this processing apparatus holds a cutting force detecting means 62 for detecting the cutting force of the rough bite, a bite driving means 63 for driving the rough bite 47 in the feed direction, and a blank tube 22 '. A work rotating means 64 having a rotating main shaft and a control means 61 for controlling them as follows are provided.
[0077]
FIG. 23 is a diagram showing a control flow of the processing apparatus of FIG.
As shown in FIG. 23, first, in step S1, the raw tube 22 'is rotated around the main shaft at a constant rotational speed, and the coarse bite is fed at a constant speed in the feed direction, so that the outer surface of the raw tube is Start rough cutting.
[0078]
Next, in step S2, the cutting force is detected by the cutting force detection means to determine whether or not the cutting force has changed. If the cutting force has not changed, the process returns to step S1 and the cutting force has changed. If so, the process proceeds to step S3.
[0079]
Next, in step S3, it is determined whether or not the cutting resistance has increased. If it has increased, the process proceeds to step S4, and if it has decreased, the process proceeds to step S5.
Next, in step S4, the feed rate is increased so as to decrease the increase in cutting resistance. Instead of increasing the feed speed, the spindle rotational speed may be decreased. Further, the increase in the cutting resistance may be reduced by combining the increase in the feed speed and the decrease in the spindle rotational speed.
[0080]
Next, in step S5, the feed rate is decreased so as to increase the decrease in cutting resistance. Instead of decreasing the feed speed, the spindle rotational speed may be increased. Further, the reduction of the cutting force may be increased by combining the reduction of the feed speed and the increase of the spindle rotational speed.
Next, in step S6, it is determined whether or not the cutting is completed. If not completed, the process returns to step S1, and if completed, the work rotating means and the tool driving means are stopped.
[0081]
Further, without providing the cutting force detecting means, it is possible to experimentally obtain the ratio of the spindle rotational speed and the feed amount by the condition setting activity and control the machining process (in terms of machining conditions). In other words, a general machining facility such as an NC lathe can sufficiently cope with a tooling path (NC program).
[0082]
According to such a processing method, by adjusting the feed speed and the rotation speed as the relative speed between the workpiece and the cutting tool, even if there is only one rough cutting tool, the thickness can be easily reduced at a low cost. Therefore, since the temperature rise rate can be improved by thinning the roller metal core, which is a raw tube as a thin cylindrical tube, it is possible to shorten the rise time.
[0083]
The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the case where there are three central rib groups and the case where there are five central rib groups has been described. Moreover, although the said embodiment demonstrated the case where there were one peripheral rib each and two each, it may be 3 or more. Further, even when rough cutting is performed with a plurality of strokes with a single rough cutting tool, further flattening of the outer surface of the raw tube can be achieved by combining the above controls. That is, various modifications can be made without departing from the scope of the present invention.
[0084]
【Example】
The raw tube 22 ′, which is a thin cylindrical tube to be processed, is made of an AL alloy material made of A3000 series, and its size is φ40 × 380 L × t1.2. In forming the reinforcing ribs 26, 25b, and 25c, a CNC lathe was used as a processing machine, and main processing conditions were a spindle rotation speed of 600 rpm and an indentation amount of φ1.0 mm.
The base tube 22 'was chucked at both centers via a rotation center with a center member fixed to the spindle chuck of the CNC lathe as a processing machine and the other end of the core tube 22'.
[0085]
Next, after rotating the main shaft under the above-mentioned conditions, the 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 set to 0.1 mm / rev.
The main dimensions of the spinning roller 45 used at this time were an outer diameter of φ100 and the tip portion having a width of 1.0 mm.
[0086]
As a result, the formed recesses 26 ', 25b' and 25c 'had a depth of 0.6 to 0.8 mm and a width of 1.0 to 1.2 mm. The reinforcing ribs 26, 25b and 25c formed on the inner surface were also formed in a cross-sectional shape having a depth of 0.3 to 0.5 mm and a width of 0.8 to 1.8 mm and showing a smooth ridgeline.
[0087]
Next, with the base tube 22 'being chucked, outer diameter cutting was performed using a diamond bit with a nose radius of 0.4 at a spindle speed of 4500 rpm and a feed rate of 0.1 mm / rev. As a result, the surface roughness Rz was about 3 to 4 μm.
[0088]
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, up to a desired thickness t = 0.4 mm, as shown in FIG. When cutting is performed at a constant feed speed and a constant rotation speed along the tool trajectory 149 with the cutting blade 147 of FIG. 18, as shown in FIG. Since the “relief” 150 is generated on the inner side due to the resistance at the time of cutting, a rise 148 (reversely, the vicinity of the convex portion is recessed in the cross-sectional direction) as shown in FIG. For this reason, it is not possible to obtain a uniform surface as a specification for the fixing roller. As this specification, generally, a surface roughness Rz of 2 μm or less and a surface waviness Wcm of 3 μm or less are generally required.
[0089]
Therefore, as shown in FIGS. 20 and 21, a uniform surface can be obtained by adjusting the rotation speed of the main shaft and the cutting feed amount for holding the raw pipe as a workpiece. In FIG. 19B, the curve R1 is the cutting resistance when the relative speed between the workpiece and the cutting tool in FIG. 19A is adjusted, and the curve R2 is the cutting resistance in the case of FIG.
[0090]
By performing the processing according to the present invention as described above, it is possible to easily obtain a high-precision thin-walled cylindrical tube and to manufacture a high-strength thin-walled cylindrical tube having a uniform surface necessary as a fixing roller. Become.
[0091]
Further, post-treatment as a fixing roller is sandblasted to roughen an alumina material having an average particle size of 50 μm (nominal particle size # 180) at a discharge pressure of 2.5 to 4.0 kgf / cm 2. 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 was coated with electrostatic powder, and then baked at 380 ° C. to form a film. The surface layer 21 formed after firing has a film thickness of about 20 to 24 μm and a surface roughness Rz of 2.5 to 3 μm. Therefore, desired surface roughness Rz ≦ 2 μm can be obtained by tape polishing the surface layer 21. If necessary, firing is performed again to smooth the surface of the fluorine film.
According to the fixing roller manufactured in this way, it is possible to achieve both thinning and high rigidity, so that the rise time can be increased and energy saving can be achieved.
[0092]
【The invention's effect】
As described above, according to the present invention, even when an aluminum alloy material is used, a method for processing a thin core metal and a method for processing an electrophotographic fixing roller core metal that are thinner and can ensure high rigidity than before. Can be provided.
Furthermore, according to this method of processing the fixing roller core for electrophotography, the rise time of the fixing roller can be greatly shortened, and power saving can also be achieved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view illustrating a configuration of a roller core of a fixing roller provided 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 rib cross-section, where (A) shows a semicircular rib, (B) shows a smoothly continuous semicircular rib, and (C) is an isosceles triangle. (D) shows a U-shaped rib, and (E) shows a trapezoidal rib.
FIG. 3 is a further enlarged view of a rib cross section.
4 is a longitudinal sectional view of a fixing device including a fixing roller having the roller cored bar of FIG. 1. FIG.
FIG. 5 is a partial cross-sectional view showing a roller metal 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 according to the present invention.
FIG. 7 is a diagram illustrating a fixing roller used in an electrophotographic image forming apparatus.
FIGS. 8A and 8B are diagrams showing a technical problem of a thin fixing roller, in which FIG. 8A shows a case of bending deformation and FIG. 8B shows a case of crushing deformation.
FIGS. 9A and 9B are diagrams showing a method for manufacturing an electrophotographic fixing roller, in which FIG. 9A is a drawing process of an end (journal) of a blank tube, and FIG. 9B is an end face and chamfering process. Yes, (C) is a cutting process by an end mill, (D) is a reinforcing rib forming process, (E) is a trunk cutting process, (F) is a coating process, and (G) is a tape polishing process.
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, FIG. 10A is a front view, and FIG. .
11 is a diagram showing a reinforcing rib forming step in FIG. 9D and a trunk cutting step in FIG. 9E.
FIG. 12 is a view showing a reference example of a reinforcing rib forming step.
13 shows a spinning roller used in the reinforcing rib forming apparatus of FIG. 10, wherein (A) is a side view and (B) is a partially sectional perspective view.
14 is an enlarged view of the main part of the body cutting process of FIG. 9E, (A) is a diagram showing a state before the formation of the reinforcing rib, (B) is a diagram showing a state after the rib formation, (C) is a figure which shows the cutting state after rib formation.
FIGS. 15A and 15B are diagrams illustrating the order of forming ribs in the reinforcing rib forming step of FIG. 9D, wherein FIG. 15A shows the first processing, FIG. 9B shows the middle of processing, and FIG.
16 is a view showing a modification in the reinforcing rib forming step of FIG. 9D. FIG.
17 shows a turret lathe used in the reinforcing rib forming step of FIG. 9D and the trunk cutting step of FIG. 9E, where FIG. 17A is a front view and FIG.
18A and 18B are diagrams showing one-time cutting in a reference example, where FIG. 18A shows an ideal state and FIG. 18B shows an actual cutting state.
19A shows the cutting state of the rough cutting tool according to the cutting method of the present invention, and FIG. 19B shows the periphery of the rib between the one-time cutting of the reference example of FIG. 18B and the cutting according to the present invention. It is a figure which shows cutting resistance.
FIG. 20 is a diagram showing the spindle speed according to an embodiment of the processing method of the present invention.
FIG. 21 is a diagram showing a cutting feed amount according to an embodiment of the processing method of the present invention.
FIG. 22 is a schematic view showing an example of a processing apparatus used in the processing method of the present invention.
23 is a diagram showing a control flow of the processing apparatus of FIG.
[Explanation of symbols]
2 Fixing roller
20 Roller core (core metal structure)
22 Body
22b Inner peripheral surface
22c Micro recess
25 Central rib group
25a Center rib
25b End rib
26 Ribs
S1 width (pitch)
S2 width (pitch)

Claims (4)

In a processing method of forming ribs on the inner surface of a thin core metal by rotating the thin core metal while supporting both ends of a hollow cylindrical thin core metal and pressing a pressing member against the surface of the thin core metal ,
Relative speed between the thin cored bar and the cutting means for cutting so that the cutting resistance becomes close to a constant when the recess formed by the pressing member is removed by cutting on the outer peripheral surface of the thin cored bar. A method for processing a thin cored bar characterized by adjusting the thickness. In the adjustment of the relative speed, the feeding speed in the axial direction of the cutting means with respect to the thin metal core is higher in the outer peripheral surface portion corresponding to the portion with the rib than in the outer peripheral surface portion corresponding to the portion without the rib. The method for processing a thin cored bar according to claim 1, wherein the setting is made as follows. The adjustment of the relative speed is performed by changing the rotational speed of the main shaft that holds the thin metal core with respect to the cutting means, the outer peripheral surface portion corresponding to a portion having the rib rather than the outer peripheral surface portion corresponding to the portion where the pressing member does not have the rib. 2. The method for processing a thin cored bar according to claim 1, wherein the thickness is set to be lower. A method for processing a thin cored bar whose outer peripheral surface has a drum shape, wherein the outer surface of the thin cored bar is formed with a recess formed on the outer surface in order to form a rib on the inner surface. In the method of processing the core metal,
A fixing roller for an electrophotographic apparatus, wherein, when the recess is removed by cutting, a relative speed between the thin cored bar and the cutting means for cutting is adjusted so that a cutting resistance becomes almost constant. Processing method for cored bar.

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