JP2006267462A - Developing roller and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller and a method for manufacturing the same in which axial displacement of a flange is suppressed. <P>SOLUTION: In the developing roller 10, the flanges 16A, 16B are press fitted into end part openings 12a, 12b of a sleeve 12. When the press fitting of the flanges 16A, 16B, a small diameter part 40 is put into the end part openings 12a, 12b of the sleeve 12, and the small diameter part 40, a reduced-diameter part 42, and a large diameter part 44 are accommodated in the sleeve 12, in this order. When the axial displacement exists between the flanges 16A, 16B and the sleeve 12, the axial alignment between the flanges 16A, 16B and the sleeve 12 is performed when the outer diameter of the flanges 16A, 16B agrees with the inner diameter of the end part of the sleeve 12, in the reduced-diameter part 42, thereby eliminating the axial displacement. In the state in which the axial alignment is performed, the large diameter part 44 is smoothly accommodated in the end part openings 12a, 12b of the sleeve 12, and the press fitting of the flanges 16A, 16B is completed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing roller used in an electrophotographic developing device such as a copying machine, a facsimile machine, and a printer, and a manufacturing method thereof.

  Conventionally, as a developing roller used in an electrophotographic developing device such as a copying machine, a facsimile machine, or a printer, a magnet roll having a plurality of magnetic poles formed on the surface thereof, and a cylindrical sleeve in which the magnet roll is accommodated A developing roller composed of a pair of flanges coupled to both ends of a sleeve containing a magnet roll is disclosed in Patent Document 1 below.

In such a developing roller, the developer adsorbed on the surface of the sleeve is conveyed to the developing region by rotating only the outer sleeve while the shaft of the magnet roll is fixed. The developer conveyed to the development area is supplied to the photosensitive drum, and the electrostatic latent image formed on the surface of the photosensitive drum is visualized. The developer remaining on the sleeve side without being supplied to the photosensitive drum is peeled off from the sleeve when it reaches the developer peeling region by the rotation of the sleeve.
Japanese Utility Model Publication No. 5-90518

  The accuracy of rotation of the sleeve as described above greatly depends on the accuracy of coupling of the flange to the sleeve. That is, if the flange and the sleeve are coupled with the center axis of the flange shifted from the center axis of the sleeve, the center axis of the sleeve does not match the center axis of the sleeve, and as a result, the accuracy of development by the developing roller Will deteriorate. Therefore, the inventors have newly found a technique capable of significantly suppressing the axial displacement of the flange as a result of keen research. In addition, the state where the shaft is displaced is a state where the center axis of the flange and the center axis of the sleeve are relatively inclined, or a state where the center axis of the flange and the center axis of the sleeve are displaced in parallel. .

  On the other hand, the conventional developing roller described above has the following problems. That is, as clearly shown in FIG. 1 and the like of Patent Document 1, the inner diameter of the sleeve (Df in the figure) is larger than the outer diameter of the flange (df in the figure), and the clearance thereof Therefore, even if the flange is fitted to the sleeve, the flange and the sleeve are likely to be misaligned. Even if the flange is fixed to the sleeve using an adhesive, it is difficult to make the center axis of the flange and the center axis of the sleeve exactly coincide with each other. It is highly probable that this has occurred. When such a shaft misalignment is large, the accuracy of development by the developing roller deteriorates.

  That is, an object of the present invention is to provide a developing roller in which the axial displacement of the flange is suppressed and a method for manufacturing the developing roller.

  A developing roller according to the present invention includes a cylindrical sleeve that accommodates a magnet roll, and a flange that is press-fitted into the end opening of the sleeve from the tip side, and the flange is substantially the same as the inner diameter of the end of the sleeve, or A large-diameter portion having an outer diameter equal to or greater than the inner diameter, and a small-diameter located closer to the front end of the flange than the large-diameter portion and having an outer diameter smaller than the inner diameter of the end portion of the sleeve and smaller than the outer diameter of the large-diameter portion. And a reduced diameter portion which is interposed between the large diameter portion and the small diameter portion and whose outer diameter gradually decreases from the large diameter portion toward the small diameter portion.

  In this developing roller, a flange having a large diameter portion, a small diameter portion, and a reduced diameter portion is press-fitted into the end opening of the sleeve. When the flange is press-fitted, first, a small diameter portion on the flange tip side is accommodated in the end opening of the sleeve and accommodated in the sleeve in the order of the small diameter portion, the reduced diameter portion, and the large diameter portion. At this time, if there is an axial misalignment between the flange and the sleeve, when the outer diameter of the flange matches the inner diameter of the end of the sleeve in the reduced diameter portion, the shaft is aligned with the flange. Is performed to eliminate the axis misalignment. When the flange is further pressed and accommodated in the sleeve with the shaft aligned, the outer diameter of the reduced diameter portion in contact with the opening edge gradually approaches the outer diameter of the large diameter portion, and the end of the sleeve The large-diameter portion is smoothly accommodated in the portion opening, and the press-fitting of the flange is completed. That is, after the shaft alignment is performed, the flange and the sleeve are maintained in the state until the press-fitting of the flange into the sleeve is completed, so that the flange is press-fitted into the sleeve without being substantially displaced. The

  Further, it is preferable that the outer peripheral surface of the reduced diameter portion is inclined at an inclination angle of 30 ° or less with respect to the axis of the flange.

  Further, the difference between the outer diameter of the small diameter portion and the outer diameter of the large diameter portion is preferably in the range of 20 μm or more and 100 μm or less, and the length of the large diameter portion in the axial direction of the flange is 1.0 mm or more. Preferably, the length of the small diameter portion in the axial direction of the flange is preferably 0.2 mm or more.

  A developing roller manufacturing method according to the present invention is a developing roller including a cylindrical sleeve that accommodates a magnet roll, and a flange that is press-fitted into the end opening of the sleeve from the front end side. A large-diameter portion having an outer diameter that is substantially the same as or larger than the inner diameter of the portion, and an outer diameter of the large-diameter portion that is located closer to the front end of the flange than the large-diameter portion and smaller than the inner diameter of the sleeve end portion A developing roller having a small-diameter portion having a smaller outer diameter, and a reduced-diameter portion that is interposed between the large-diameter portion and the small-diameter portion, and whose outer diameter gradually decreases from the large-diameter portion toward the small-diameter portion. The step of fitting the small diameter part of the flange into the end opening of the sleeve and aligning the flange with the sleeve, and pressing the flange along the extending direction of the sleeve, the large diameter of the flange Part is sleeve Characterized in that it comprises a step of press-fitting to fit the end opening.

  In this developing roller manufacturing method, when the flange is press-fitted into the sleeve, first, the small diameter portion on the flange tip side is placed in the end opening of the sleeve, and the small diameter portion, the reduced diameter portion, and the large diameter portion are arranged in this order. To house. At this time, if there is an axial misalignment between the flange and the sleeve, when the outer diameter of the flange matches the inner diameter of the end of the sleeve in the reduced diameter portion, the axis alignment of the flange and the sleeve is performed. Is performed to eliminate the axis misalignment. When the flange is further pressed and accommodated in the sleeve with the shaft aligned, the outer diameter of the reduced diameter portion in contact with the opening edge gradually approaches the outer diameter of the large diameter portion, and the end of the sleeve The large-diameter portion is smoothly accommodated in the portion opening, and the press-fitting of the flange is completed. That is, after the shaft alignment is performed, the flange and the sleeve are maintained in the state until the press-fitting of the flange into the sleeve is completed, so that the flange is press-fitted into the sleeve without being substantially displaced. The

  Moreover, it is preferable that the step of performing axial alignment of the flange and the step of performing press-fitting of the flange are performed by one continuous operation. In this case, the process of press-fitting the flange into the sleeve is simplified and the work time is shortened.

  ADVANTAGE OF THE INVENTION According to this invention, the developing roller with which the axial shift of the flange was suppressed and its manufacturing method are provided.

  Embodiments of a developing roller and a manufacturing method thereof according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected about the same or equivalent element, and the description is abbreviate | omitted when description overlaps. In addition, the present invention is not limited to the following embodiment, and is merely an embodiment.

  FIG. 1 is a schematic perspective view of a developing roller 10 according to an embodiment of the present invention. FIGS. 2 and 3 are a sectional view taken along line II-II and a sectional view taken along line III-III, respectively, of the developing roller 10 shown in FIG. FIG.

  As shown in FIGS. 1 to 3, the metal sleeve 12 having a long cylindrical shape, the magnet roll 14 disposed inside the sleeve 12, and the end openings 12 a and 12 b of the sleeve 12 are fitted and fixed. The developing roller 10 is composed of the pair of flanges 16A and 16B.

  Further, the magnet roll 14 includes a substantially round rod-shaped shaft 18 and five long magnet blocks 20 (20A to 20E) fixed to the outer peripheral surface 18a of the shaft 18.

  The shaft 18 is made of a high-strength material such as metal, and its length is longer than that of the magnet block 20. The magnet block 20 is not fixed to both ends 18b and 18c of the shaft 18, and is exposed.

Each magnet block 20 is a plastic magnet or rubber magnet composed of magnetic powder (ferrite-based or Nd-Fe-B-based) and resin (rubber-based or plastic-based). The sectional shape of each magnet block 20, as shown in FIG. 3, the first and arc A _1, the first arc A ₁ and same curvature having substantially the same curvature as the outer peripheral surface 18a of the shaft 18 second and arc a ₂ is larger curvature radius than the first arc a ₁ has a central and opening angle, straight line connecting the first corresponding end points of the arc a ₁ and the second arc a ₂ 2 The shape is formed by the line segments L ₁ and L ₂ . A curved surface in which the first arc A ₁ extends in the longitudinal direction of the magnet block 20 is an inner peripheral curved surface 20 a of the magnet block 20, and the second arc A ₂ also extends in the longitudinal direction of the magnet block 20. The curved surface is the outer peripheral curved surface 20b of the magnet block 20, and a pair of planes in which the _two line segments L ₁ and L ₂ extend in the longitudinal direction of the magnet block 20 are both side planes 20c and 20d of the magnet block 20. It has become.

  And each magnet block 20 is being fixed to the outer peripheral surface 18a of the shaft 18 with the adhesive agent which is not shown in figure in the inner peripheral curved surface 20a. Since each magnet block is in contact with the adjacent magnet block 20 on at least one of the two side surfaces 20c and 20d, each magnet block 20 is firmly attached to the shaft 18. The shaft 18 is not completely surrounded by the magnet block 20, and a block missing portion 22 where the magnet block 20 does not exist is formed around the shaft 18. , The outer peripheral surface 18a of the shaft 18 is exposed.

  In addition, the polarities of the magnet blocks 20A to 20E on the outer peripheral curved surface 20b are arranged so that the N pole and the S pole are alternated as indicated by the reference numerals N and S in FIG. A gap having a predetermined distance d is formed between the outer peripheral surface 14 a of the magnet roll 14 formed by the outer peripheral curved surface 20 b of the magnet block 20 and the inner peripheral surface 12 c of the sleeve 12.

The magnet roll 14 described above is disposed in the sleeve 12 so as to extend in the same direction as the extending direction of the sleeve 12, and is rotatably supported by a pair of flanges 16A and 16B located at both ends of the sleeve 12. Has been. Here, the flange 16A and the flange 16B is adapted its outer shape is a substantially thick disk shape, each hole 24A along its central axis I _2, 24B are formed. Bearings 26A and 26B (for example, sintered oil-impregnated bearings) that rotatably support the shaft 18 are attached to the insides of the holes 24A and 24B.

Note that the flange 16A, the cylindrical shaft portion 30A that protrudes from the outer surface to the axis _{I 1} and coaxially of the shaft 18 is formed, one end portion 18b of the flange 16A of the shaft 18, the flange 16A It penetrates the hole 24A and the shaft portion 30A and protrudes to the outside of the case 28 constituted by the sleeve 12 and the pair of flanges 16A and 16B. On the other hand, the other end 18c of the shaft 18 on the flange 16B side is usually located in the bottomed hole 24B of the flange 16B. This flange 16B, the shaft portion 30B of the round bar projecting from its outer surface to the axis I ₁ and coaxially of the shaft 18 is formed.

That is, the shaft 18, the case 28 (i.e., the sleeve 12 and a pair of flanges 16A, 16B) and, together are coaxially arranged with respect to the axis _{I 1} of the shaft 18, as a rotation about the axis _{I 1} of the shaft 18 The bearings 26A and 26B are relatively rotatable.

  When the developing roller 10 is installed in the developing device, as shown in FIG. 2, the end portion 18b of the shaft 18 protruding from the case 28, which is one end portion of the developing roller 10, has one side wall 32A of the developing device. Fixed to. Further, the shaft portion 30B of the flange 16B, which is the other end portion of the developing roller 10, is rotatably supported via a bearing 34 on the other side wall 32B of the developing device.

  That is, when the developing roller 10 is installed in the developing device, the magnet roll 14 is held so as not to rotate, and only the case 28 that covers the magnet roll 14 is held rotatably around the shaft 18. In this state, the rotation of the case 28 of the developing roller 10 is controlled by attaching a gear or the like to the shaft portion 30B of the flange 16B and rotating the shaft portion 30B by a motor or the like.

  When the case 28 of the developing roller 10 installed in the developing device rotates, the developer carried on the outer peripheral surface 28a of the case 28 (that is, the outer peripheral surface 12d of the sleeve) faces the photosensitive drum (not shown). The toner contained in the developer adheres to the electrostatic latent image on the photosensitive drum, and the electrostatic latent image is visualized. As the developer used for the developing roller 10, both a one-component developer only of toner and a two-component developer in which toner and a carrier are mixed can be used.

  In addition, the following installation modes different from the installation mode of the developing roller 10 in the developing device described above may be used. That is, the shaft portion 30B of the flange 16B is fixed to the side wall 32B of the developing device so as not to rotate, and the end portion 18b of the shaft 18 protruding from the case 28 is rotatably supported on the side wall 32A of the developing device. The developing roller 10 may be installed in the developing device so that only the magnet roll 14 rotates around the shaft 18 inside the case 28 without rotating. Further, both the magnet roll 14 and the case 28 may be rotatably supported on the side walls 32A and 32B of the developing device, and the developing roller 10 may be installed so as to rotate independently of each other.

  Next, the fitting state of the sleeve 12 and the flange 16B will be described in detail with reference to FIG.

  As shown in FIG. 4, a small diameter portion 40, a reduced diameter portion 42, a large diameter portion 44 and a cap portion 48 are formed on the flange 16 </ b> B in order from the tip side.

Small-diameter portion 40 is at the forefront of the flange 16B, the length in the axial line _{I 2} direction of the flange 16B (X direction in FIG. 4) is equal to or greater than 0.2 mm (e.g., 0.5 mm). Further, the outer diameter D ₁ (for example, 18.97 mm) of the small diameter portion 40 is smaller than the inner diameter D _A (19.00 mm) of the sleeve 12. The edge portion on the distal end side of the small-diameter portion 40 is chamfered so that the flange 16B can be easily accommodated in the sleeve 12.

The length in the axial _{I 2} direction of the flange 16B of the large-diameter portion 44 above 1.0 mm (e.g., 2.0 mm) is, more preferably in the range of 1.5Mm～10mm. Here, if the length of the flange 16B is less than 1.0 mm, the contact area between the outer peripheral surface 44a of the large-diameter portion 44 and the inner peripheral surface 12c of the sleeve 12 cannot be sufficiently ensured, and the fixing strength when press-fitted is insufficient. On the other hand, when the length of the flange 16B exceeds 10 mm, the sleeve 12 is necessarily extended in that the magnet block 20 having a predetermined length is accommodated in the sleeve 12, and the developing roller 10 is reduced in size. It becomes difficult.

Outer diameter _{D 2} of the large-diameter portion 44 (e.g., 19.02Mm) is larger than the inner diameter _{D A} of the sleeve 12. Here, the flange 16B is pressed if the end opening 12b of the sleeve 12, the outer diameter _{D 2} of the large diameter portion 44 is approximately equal to the inner diameter _{D A} of the sleeve, or its inner diameter _{D A} more desired size The thickness can be selected as appropriate. The outer diameter _{D 2} of the large diameter portion 44, as compared to the inner diameter _{D A} of the end opening 12b of the sleeve 12 is preferably larger in the range of 100 [mu] m. Since the outer diameter D ₂ of the large diameter portion 44, is smaller than the inner diameter D _A of the end opening 12b of the sleeve 12 is higher press fit is difficult strength, whereas, in the end opening 12b of the sleeve 12 If greater than the 100μm than the inner diameter D _a, the pressure required for press-fitting is thereby causing the deformation of the higher becomes the sleeve 12 and the flange 16B.

In other words, the outer diameter _{D 1} of the small diameter portion 40, 0.05 mm only smaller than the outer diameter _{D 2} of the large-diameter portion 44, it is preferred that the difference is 20μm or more 100μm or less. Here, there is a difference between the outer diameter D ₂ of the outer diameter D ₁ and the large-diameter portion 44 of the small-diameter portion 40 when less than 20 [mu] m, inserted ease to the sleeve 12 of the small-diameter portion 40 is impaired, inserted Work takes time and effort. If the insertion is not successful, the flange 16B may be bent at the time of press-fitting, resulting in a defective product. The outer diameter D ₁ of the small diameter portion 40 difference in 100μm or less of the outer diameter D ₂ of the large-diameter portion 44, it is possible to easily correct the axial deviation.

As described above, the outer diameter _{D 2} of the large diameter portion 44, since is larger than the inner diameter _{D A} of the sleeve, the developing roller 10, the outer peripheral surface 44a of the large-diameter portion 44 of the flange 16B is The sleeve 12 is in direct contact with the inner peripheral surface 12c of the sleeve 12 without an adhesive. That is, since there is substantially no gap between the outer peripheral surface 44 a of the large diameter portion 44 and the inner peripheral surface 12 c of the sleeve 12, the flange 16 B and the sleeve 12 can be connected even after the flange 16 B is press-fitted into the sleeve 12. Axis misalignment is suppressed. In addition, you may press-fit using an adhesive agent suitably, and in this case, an adhesive agent reinforces the adhesive strength of the flange 16B and the sleeve 12. FIG. In this case, in the small diameter portion 40 and the reduced diameter portion 42, the flange 16B may be fixed to the inner peripheral surface 12c of the sleeve 12 with an adhesive.

  The reduced diameter portion 42 is interposed between the small diameter portion 40 and the large diameter portion 44, and the outer diameter thereof is gradually reduced from the large diameter portion 44 toward the small diameter portion 40 at an inclination angle θ. The inclination angle θ is preferably in the range of 0 ° <θ ≦ 30 °, and more preferably in the range of 0 ° <θ ≦ 15 °. Here, if the inclination angle θ exceeds 30 °, a high pressure is required at the time of press-fitting, and the edge 12e (see FIG. 5) of the end opening 12b of the sleeve 12 is reduced in diameter as shown in the embodiment described later. 42 is likely to cause a shaft misalignment.

The cap portion 48 defines the press-fit depth of the flange 16B and is provided to securely seal the sleeve 12 by the flange 16B. The outer diameter of the cap portion 48 is the outer diameter D _B (for example, 20.. 00mm) or less.

  Next, a procedure for fitting the flange 16B to the sleeve 12 will be described with reference to FIG.

First, as shown in FIG. 5A, the flange 16B is brought close to the end opening 12b of the sleeve 12 from the front end side, and the small diameter portion 40 is put into the end opening 12b. In this case, the small-diameter portion 40, as shown in FIG. 4, therefore the outer diameter D ₁ is smaller than the inner diameter D _A of the sleeve 12, it is possible to easily fit the end opening 12b. In particular, when the flange 16B is slid toward the sleeve 12 with the small diameter portion 40 applied to the edge 12e of the end opening 12b, the flange 16B can be easily inserted into the sleeve 12. In addition, since the edge portion on the distal end side of the small diameter portion 40 is chamfered, the flange 16B can be easily inserted into the sleeve 12.

  At this time, if the length of the small-diameter portion 40 is 0.2 mm or more, the small-diameter portion 40 can be easily applied to the edge portion 12e of the end opening 12b and can be easily slid. In addition, it is preferable that the length of this small diameter part 40 is the range of 0.3 mm-10 mm, and it is more preferable that it is the range of 0.3 mm-5 mm. Here, if the length of the small-diameter portion 40 is less than 0.2 mm, the ease of insertion as described above may be impaired, and the insertion work takes time and effort. If the insertion is not successful, the flange 16B may be bent at the time of press-fitting, resulting in a product defect. On the other hand, if the length of the small diameter portion 40 is 0.2 mm or more, the flange 16B can be easily inserted into the sleeve 12. However, if the length of the small-diameter portion 40 exceeds 10 mm, it becomes uselessly long and the magnet block 20 having a predetermined length is accommodated in the sleeve 12. Accordingly, it is inevitable that the developing roller 10 is downsized.

Then, after the entire small diameter portion 40 is accommodated in the end opening 12b of the sleeve, the flange 16B is extended in the extending direction of the sleeve 12 (ie, the reduced diameter portion 42 and the large diameter portion 44 are sequentially accommodated in the sleeve 12). , In the axial direction). At the time of this pressing, the inner diameter of the end portion of the sleeve 12 and the outer diameter of the reduced diameter portion 42 coincide with each other as shown in FIG. That is, the reduced diameter portion 42 has a portion that matches the diameter of the edge portion of the end opening 12b (that is, the diameter D _A of the sleeve inner peripheral surface 12c). Fits snugly. At this time, the diameter-reduced portion 42 is in contact with the inner peripheral surface 12c of the sleeve 12 over the entire circumference of the outer diameter with equal pressure, and the axes I ₁ and I of the flange 16B and the sleeve 12 both having a true circular cross section. Axis alignment in which the _two match with high accuracy is realized. Then, after the axes are aligned so that the axes I ₁ and I ₂ coincide with each other, the flange 16B is further pressed as a continuous series of operations, and the large-diameter portion 44 becomes an end portion as shown in FIG. Press fit to fit in the opening 12b.

When the flange 16B is press-fitted, the flange 16B that has been in contact with the edge 12e of the end opening 12b in the reduced diameter portion 42 transitions to a state in which it is in contact with the edge 12e of the end opening 12b in the large diameter portion 44. . Here, since the outer diameter of the reduced diameter portion 42 is inclined so as to approach the outer diameter D ₂ of the large diameter portion 44, from a state in which reduced diameter portion 42 is in contact with the edge 12e of the end opening 12b, The transition is smoothly made until the large-diameter portion 44 is in a state of being accommodated in the end opening 12b. That is, when the flange 16B is press-fitted into the sleeve 12, the end portion 12b is smoothly accommodated up to the large diameter portion 44. Since such a smooth press-fitting is performed, the axial alignment between the sleeve 12 and the flange 16B is hardly hindered, and the aligned state is maintained even when the large-diameter portion 44 is press-fitted. As a result, the flange 16B is press-fitted into the sleeve 12 without being substantially misaligned.

  Further, as described above, the step of performing axial alignment between the flange 16B and the sleeve 12 and the step of performing press-fitting of the flange 16B are performed by one continuous operation, so that these steps are performed separately. Compared to the case, the process of press-fitting the flange 16B into the sleeve 12 is simplified, and the work time is shortened.

  In the above, only one flange (drive side flange) 16B of the pair of flanges 16A and 16B of the developing roller 10 has been described, but the other flange (driven side flange) 16A also has the same end as the flange 16B. A small diameter portion 40, a reduced diameter portion 42, a large diameter portion 44, and a cap portion 48 are formed. Therefore, it is possible to press-fit the flange 16 </ b> A substantially without axial misalignment. Note that only one of the pair of flanges 16A and 16B of the developing roller 10 is the same as or equivalent to the small diameter portion 40, the reduced diameter portion 42, and the large diameter portion 44 described above. The flange may be press-fitted with substantially no axial misalignment.

  Thereby, it is possible to obtain the developing roller 10 with improved shaft blurring accuracy. In addition, it can be expected that application unevenness such as a copying machine using the developing roller 10 can suppress the occurrence of uneven image quality. Moreover, according to the manufacturing method of the developing roller 10 described above, it is possible to manufacture the developing roller 10 in which the axial displacement of the flanges 16A and 16B with respect to the sleeve 12 is suppressed with a high yield.

  The present invention is not limited to the above embodiment, and various modifications are possible. For example, it is not always necessary to provide a cap portion on the flange. Further, only the flange in which the small diameter portion, the reduced diameter portion, and the large diameter portion are formed in order from the distal end side has been described, but a flange having a reduced diameter portion or a small diameter portion appropriately formed after the large diameter portion may be used. Furthermore, although only the two-stage flange has been described, it can be appropriately changed to a three-stage or more multi-stage flange.

  Hereinafter, in order to clarify the preferable range of the inclination angle of the diameter-reduced portion of the flange, description will be made using examples and comparative examples.

  First, a plurality of types of flanges similar to the flange 16B described above, which differ only in the inclination angle of the reduced diameter portion, were prepared. That is, 100 samples each of sample A having an inclination angle of 5 °, sample B having an inclination angle of 14 °, and sample C having an inclination angle of 45 ° were prepared. In these samples, when press-fitting the flange into the sleeve, first, the small diameter portion of the flange is manually housed in the sleeve, and then the flange is pressed at a pressure of 0.5 MPa using a vertical flange press-fitting machine. Press-fitted into the sleeve. Each sample was press-fitted into a sleeve similar to the sleeve 12 described above, and the size of the axial deviation was measured. The length of the sleeve used in this example is 310 mm, and the outer diameter is 20 mm.

  A specific measurement method is as follows. That is, as shown in FIG. 2, at the predetermined support point of the shaft portion 30A of the flange 16A and the predetermined support point of the shaft portion 30B of the flange 16B, the sleeve is supported by supporting both sides of the developing roller at a distance between support points of 320 mm. The amount of deflection at the center position of the sleeve and both end positions of the sleeve (positions 20 mm from the end face) was measured. For measurement, a laser shake measuring machine was used. Then, in each sample, a sample in which any of the above three positions exceeded 15 μm was assumed to have a large axial deviation, and the ratio (that is, the product defect ratio) was examined.

  As a result, the product defect rate was 0% in sample A, the product failure rate was 2% in sample B, and the product failure rate was 11% in sample C. As is clear from this result, in the samples A and B in which the inclination angle of the reduced diameter portion is 30 ° or less, almost no axial misalignment is confirmed, while the sample in which the inclination angle of the reduced diameter portion is larger than 30 °. In C, misalignment was confirmed in many samples. That is, it was confirmed by this example that the occurrence of axial deviation is significantly suppressed by setting the inclination angle θ of the reduced diameter portion of the flange to 30 ° or less. In the flange where the inclination angle θ of the reduced diameter portion is 30 ° or less, the factor that suppresses the occurrence of the axial deviation as described above is that the opening edge portion of the sleeve is smoothed by making the inclination of the reduced diameter portion gentle. It is thought that this is because the situation of biting into the reduced diameter portion of the flange is suppressed.

1 is a schematic perspective view of a developing roller according to an embodiment of the present invention. It is the II-II sectional view taken on the line of the developing roller shown in FIG. FIG. 3 is a cross-sectional view of the developing roller shown in FIG. 1 taken along the line III-III. It is a principal part enlarged view of sectional drawing shown in FIG. It is the figure which showed the procedure of attaching a flange to a sleeve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Developing roller 14, 14A ... Magnet roll, 16A, 16B ... Flange, 18 ... Shaft, 20, 20A-20I ... Magnet block, 20a ... Inner curved surface, 20b ... Outer curved surface, 20c, 20d ... Both side planes, 40 ... small diameter part, 42 ... reduced diameter part, 44 ... large diameter part, D _A , D _B , D ₁ , D ₂ ... diameter.

Claims (7)

A cylindrical sleeve that houses the magnet roll;
A flange press-fitted from the front end side into the end opening of the sleeve;
The flange is
A large diameter portion having an outer diameter substantially equal to or greater than the inner diameter of the end of the sleeve;
A small-diameter portion that is located closer to the front end of the flange than the large-diameter portion, and has an outer diameter smaller than the inner diameter of the end portion of the sleeve and smaller than the outer diameter of the large-diameter portion;
A developing roller having a reduced diameter portion interposed between the large diameter portion and the small diameter portion and having an outer diameter gradually decreasing from the large diameter portion toward the small diameter portion.   The developing roller according to claim 1, wherein an outer peripheral surface of the reduced diameter portion is inclined at an inclination angle of 30 ° or less with respect to an axis of the flange.   The developing roller according to claim 1, wherein a difference between an outer diameter of the small diameter portion and an outer diameter of the large diameter portion is in a range of 20 μm to 100 μm.   The developing roller according to claim 1, wherein a length of the large-diameter portion in the axial direction of the flange is 1.0 mm or more.   The developing roller according to any one of claims 1 to 4, wherein a length of the small diameter portion in the axial direction of the flange is 0.2 mm or more. A developing roller comprising a cylindrical sleeve that houses a magnet roll, and a flange that is press-fitted into the end opening of the sleeve from the front end side,
The flange is positioned on the front end side of the flange with respect to the large diameter portion having an outer diameter substantially equal to or greater than the inner diameter of the end portion of the sleeve, and on the end portion of the sleeve. A small-diameter portion having an outer diameter smaller than the inner diameter and smaller than the outer diameter of the large-diameter portion, and interposed between the large-diameter portion and the small-diameter portion, and outward from the large-diameter portion toward the small-diameter portion. Used to produce a developing roller having a diameter-reduced portion that is gradually reduced in diameter,
Storing the small-diameter portion of the flange in an end opening of the sleeve, and performing axial alignment of the flange with respect to the sleeve;
And a step of pressing the flange along the extending direction of the sleeve and press-fitting the large-diameter portion of the flange into the end opening of the sleeve.   The manufacturing method of the developing roller according to claim 6, wherein the step of performing axial alignment of the flange and the step of performing press-fitting of the flange are performed by one continuous operation.

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