Developer carrier and method for manufacturing the same

Abstract

This provides a strong bond between the sleeve and the flange while preventing adhesive from seeping out onto the outer surface of the sleeve. [Solution] The developer carrier comprises a shaft, a magnet, a sleeve, a flange, and an adhesive. The flange has a first fitting portion, a second fitting portion, and a groove. The adhesive is placed in the groove. The first and second grooves are formed in this order, continuously from the first fitting portion side toward the second fitting portion side. The height from the bottom surface of the second groove to the outer circumferential surface of the first fitting portion is greater than the height from the bottom surface of the first groove to the outer circumferential surface of the first fitting portion.

Description

Technical Field

[0001] The present invention relates to a developer carrier and a method for manufacturing the same.

Background Art

[0002] An electrophotographic image forming apparatus includes a developing device. A developer carrier is installed in the developing device. The developer carrier rotates while carrying a developer and supplies the developer to an image carrier.

[0003] The developer carrier (magnetic roll) of Patent Document 1 includes a cylindrical sleeve, a magnet disposed inside the sleeve, and a flange (end member) fixed to an end opening of the sleeve. The developer is carried on the outer peripheral surface of the sleeve.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, the flange is fitted inside the sleeve. And an adhesive is disposed between the sleeve and the flange. In this configuration, the fixing of the flange to the sleeve becomes strong. However, when an adhesive is used for fixing the flange to the sleeve, the adhesive may protrude onto the outer peripheral surface of the sleeve. Since the outer peripheral surface of the sleeve is a carrier surface for the developer, if the adhesive protrudes onto the outer peripheral surface of the sleeve, image defects will occur.

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide a developer carrier and a method for manufacturing the same that can strengthen the fixing between the sleeve and the flange while suppressing the protrusion of the adhesive onto the outer peripheral surface of the sleeve. [Means for solving the problem]

[0007] The first aspected developer carrier of the present invention comprises a shaft extending in a predetermined direction, a magnet fixed to the outer circumferential surface of the shaft, a cylindrical sleeve with the shaft as its central axis and carrying a developer on its outer circumferential surface, a flange fixed to an end opening in a predetermined direction of the sleeve and rotatably supported on the shaft, rotating together with the sleeve around its central axis, and an adhesive for bonding the sleeve and the flange. The flange has a cylindrical fitting portion that fits into the inside of the sleeve through the end opening. The fitting portion has a first fitting portion that contacts the inner circumferential surface of the sleeve, a second fitting portion having the same outer diameter as the first fitting portion and contacting the inner circumferential surface of the sleeve at a position closer to the end opening than the first fitting portion, and a groove formed between the first fitting portion and the second fitting portion in a predetermined direction and recessed radially with respect to the outer circumferential surfaces of the first fitting portion and the second fitting portion. The adhesive is placed in the groove. The groove has a first groove and a second groove. The first groove and the second groove are formed in this order, continuously in a predetermined direction from the first fitting portion side toward the second fitting portion side. The height from the bottom surface of the second groove to the outer circumferential surface of the first fitting portion is greater than the height from the bottom surface of the first groove to the outer circumferential surface of the first fitting portion.

[0008] A second aspect of the present invention relates to a method for manufacturing a developer carrier, comprising the steps of: applying an adhesive to a first groove; and, with the adhesive applied to the first groove, press-fitting a fitting portion into the inside of a sleeve through an end opening. [Effects of the Invention]

[0009] The configuration of the present invention provides a strong fixation between the sleeve and the flange while preventing adhesive from overflowing onto the outer surface of the sleeve. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an image forming apparatus according to an embodiment. [Figure 2]This is a schematic diagram of a developing apparatus and its surroundings according to an embodiment. [Figure 3] This is a schematic diagram of a developing apparatus according to an embodiment. [Figure 4] This is a plan view of a developing roller according to an embodiment. [Figure 5] This is a cross-sectional view along line AA' in Figure 4. [Figure 6] This is a magnified view of the area indicated by arrow B in Figure 5. [Figure 7] This is a single-piece drawing of a flange according to an embodiment. [Figure 8] This is an enlarged view of the groove portion and surrounding area of ​​the flange according to the embodiment. [Figure 9] This figure shows the results of Experiment 1, which was conducted to confirm the effectiveness of the embodiment. [Figure 10] This figure shows the results of Experiment 2, which was conducted to confirm the effectiveness of the embodiment. [Figure 11] This figure shows the results of Experiment 3, which was conducted to confirm the effectiveness of the embodiment. [Figure 12] This figure shows the results of Experiment 4, which was conducted to confirm the effects of the embodiment. [Figure 13] This figure shows the results of Experiment 5, which was conducted to confirm the effects of the embodiment. [Figure 14] This figure shows the results of Experiment 6, which was conducted to confirm the effects of the embodiment. [Modes for carrying out the invention]

[0011] The developing roller 10 (corresponding to the "developer carrier") of this embodiment will be described below with reference to Figures 1 to 8. The developing roller 10 is installed in the image forming apparatus 1000. Specifically, the developing roller 10 is installed in the developing device 100, and the developing device 100 is installed in the image forming apparatus 1000.

[0012] The image forming apparatus 1000 is a tandem type color laser printer. However, it is not limited thereto. The image forming apparatus 1000 may be a monochrome printer, a multifunction peripheral, a facsimile machine, or the like.

[0013] In the following description, for ease of understanding, an XYZ orthogonal coordinate system is used. The Z direction is the vertical direction and is the up and down direction of the image forming apparatus 1000. The flat surface on which the image forming apparatus 1000 is installed is a plane perpendicular to the Z direction. The arrow direction of the Z axis is upward, and the opposite direction is downward.

[0014] The X direction is one direction of the horizontal direction, and the Y direction is the other direction of the horizontal direction. For example, the X direction corresponds to the front and rear direction of the image forming apparatus 1000. The Y direction corresponds to the left and right direction of the image forming apparatus 1000.

[0015] <Overall Configuration of Image Forming Apparatus> As shown in FIG. 1, the image forming apparatus 1000 includes a main conveyance path MP. The image forming apparatus 1000 also includes a sheet cassette CA. The sheet cassette CA is detachable from the main body of the image forming apparatus 1000. The sheet cassette CA accommodates sheets S used in print jobs. The sheet S is supplied from the sheet cassette CA to the main conveyance path MP. The main conveyance path MP extends from the supply position P0 of the sheet S, passes through the transfer position P1 and the fixing position P2 in this order, and reaches the discharge tray ET.

[0016] In a print job, the sheet S in the sheet cassette CA is supplied from the supply position P0 to the main conveyance path MP, and the supplied sheet S is conveyed along the main conveyance path MP. The image forming apparatus 1000 prints an image on the conveyed sheet S. In other words, the image forming apparatus 1000 transfers a toner image onto the conveyed sheet S. At the transfer position P1, the transfer process of the toner image onto the conveyed sheet S is performed. At the fixing position P, the fixing process of the toner image onto the sheet S is performed.

[0017] The image forming apparatus 1000 includes four image forming units 110 for cyan, magenta, yellow, and black. Each image forming unit 110 forms a toner image using toner of the corresponding color. Below, we will focus on one image forming unit 110 and describe its configuration. The basic configuration of each image forming unit 110 is the same as that of the others. Therefore, the configuration of the other image forming units 110 will be omitted, relying on the following description.

[0018] As shown in Figure 2, the image forming unit 110 includes a developing device 100. In addition to the developing device 100, the image forming unit 110 also includes a photosensitive drum 111, a charging device 112, an exposure device 113, and a cleaning device 114.

[0019] During image formation by the image forming unit 110, the photoreceptor drum 111 rotates. The charging device 112 charges the outer surface of the photoreceptor drum 111. The exposure device 113 exposes the outer surface of the photoreceptor drum 111 to form an electrostatic latent image on its outer surface. Then, the developing device 100 supplies toner to the outer surface of the photoreceptor drum 111 to develop the electrostatic latent image into a toner image. The cleaning device 114 removes any remaining toner from the outer surface of the photoreceptor drum 111.

[0020] Furthermore, the image forming apparatus 1000 includes an intermediate transfer belt 120, as shown in Figure 1. The intermediate transfer belt 120 is an endless belt. The intermediate transfer belt 120 contacts the outer circumferential surface of the photoreceptor drum 111 and rotates (circulates) in the direction indicated by arrow D.

[0021] The image forming apparatus 1000 is equipped with a plurality of primary transfer rollers 121. One primary transfer roller 121 is assigned to each color: cyan, magenta, yellow, and black. Each primary transfer roller 121 is positioned on the inner circumference side of the intermediate transfer belt 120. Each primary transfer roller 121 is positioned opposite the photoreceptor drum 111 that carries the toner image of the corresponding color, with the intermediate transfer belt 120 in between.

[0022] The image forming apparatus 1000 is equipped with one secondary transfer roller 122. The secondary transfer roller 122 presses against the outer surface of the intermediate transfer belt 120 at the transfer position P1. The secondary transfer roller 122 forms a transfer nip between itself and the intermediate transfer belt 120. The main transport path MP passes through the transfer nip.

[0023] In a print job, the sheet S is transported toward the transfer position P1 (i.e., the transfer nip). The sheet S passes through the transfer nip while being transported.

[0024] The intermediate transfer belt 120 receives the primary transfer of toner images from each photoreceptor drum 111. The intermediate transfer belt 120 rotates with the toner images supported on its outer surface. As the sheet S passes through the transfer nip, the sheet S comes into contact with the outer surface of the intermediate transfer belt 120. This results in a secondary transfer of the toner image to the sheet S as it passes through the transfer nip.

[0025] Furthermore, various rotating bodies in each image forming unit 110, such as the photosensitive drum 111, rotate around an axis extending in the X direction. Similarly, the primary transfer roller 121 and secondary transfer roller 122 also rotate around an axis extending in the X direction.

[0026] The image forming apparatus 1000 includes a fixing unit 130. The fixing unit 130 includes a heating roller and a pressure roller. The fixing unit 130 is positioned at fixing position P2. The heating roller has a built-in heater. The pressure roller is pressed against the heating roller. The heating roller and the pressure roller are pressed against each other, forming a fixing nip at fixing position P2.

[0027] In a print job, the sheet S, which has undergone the toner image transfer process, passes through the fixing position P2. That is, the sheet S is sandwiched in the fixing nip between the heating roller and the pressure roller. The fixing unit 130 heats the sheet S as it passes through the fixing position P2. Pressure is applied to the sheet S at the fixing position P2. The fixing unit 130 fixes the toner image to the sheet S by heating and pressurizing the sheet S that has undergone the toner image transfer process. After the fixing process, the sheet S is discharged into the discharge tray ET.

[0028] The image forming apparatus 1000 includes a transport unit (the reference numerals are omitted). The transport unit includes a pair of transport rollers. The number of transport roller pairs installed is not particularly limited.

[0029] The transport roller pair includes a pair of rollers. The pair of rollers has a transport nip between them. The transport roller pair transports the sheet S that enters the transport nip by rotating. The transport unit transports the sheet S along the main transport path MP. The transport unit also transports the sheet S along the double-sided printing transport path DP, which will be described later.

[0030] The image forming apparatus 1000 is capable of performing both single-sided printing jobs, in which a toner image is printed on only one side of a sheet S, and double-sided printing jobs, in which a toner image is printed on both sides of a sheet S. To perform double-sided printing jobs, the image forming apparatus 1000 is equipped with a double-sided printing transport path DP.

[0031] The duplex printing transport path DP branches off from the main transport path MP at branching point P3, which is downstream of the fixing position P2 in the sheet transport direction. Then, the duplex printing transport path DP rejoins the main transport path MP at merging point P4, which is upstream of the transfer position P1 in the sheet transport direction.

[0032] If the execution job is a single-sided printing job, the sheet S passes through the transfer nip only once, and the transfer process is performed once on the sheet S while it is passing through the transfer nip. After the first transfer process, the sheet S is then discharged into the output tray ET.

[0033] If the execution job is a duplex printing job, the sheet S passes through the transfer nip twice, as the transfer process is performed once on each side of the sheet S. Specifically, when the sheet S passes through the transfer nip for the first time, the transfer process is performed on one side of the sheet S. After the first transfer process, the sheet S is switched back after the rear end of the sheet S has passed the branching position P3 and before the sheet S is completely discharged into the discharge tray ET. This causes the sheet S to be pulled from its rear end into the duplex printing transport path DP.

[0034] Subsequently, the sheet S is transported along the double-sided printing transport path DP. Then, the sheet S on the double-sided printing transport path DP is returned to the main transport path MP from the merging position P4. The sheet S returned to the main transport path MP is transported along the main transport path MP and passes through the transfer nip again. At this time, the orientation of the front and back sides of the sheet S is reversed compared to when it passed through the transfer nip the previous time. As a result, when the sheet S passes through the transfer nip for the second time, the transfer process is performed on the opposite side of the sheet S to the previous side.

[0035] <Configuration of the developing device> The following description focuses on one particular developing apparatus 100 and explains its configuration. The basic configuration of each developing apparatus 100 is the same. Therefore, the configurations of the other developing apparatuses 100 will be omitted, as they will be based on the following description.

[0036] As shown in Figure 3, the developing apparatus 100 includes a developing container 101. The developing container 101 contains a developer containing toner. The developer is, for example, a magnetic one-component developer containing magnetic toner. The developing apparatus 100 supplies the toner contained in the developing container 101 to the outer surface of the photoreceptor drum 111 (i.e., the electrostatic latent image).

[0037] The developing apparatus 100 includes a developing roller 10. The developing roller 10 corresponds to a "developer carrier". The developing roller 10 is located inside the developing container 101. The developing roller 10 is supported so as to be rotatable around an axis extending in the X direction. Of the developing roller 10, only the outer peripheral portion, including its outer peripheral surface, is rotatable around the axis extending in the X direction.

[0038] The developing roller 10 exposes a portion of its outer surface to the outside of the developing container 101. Specifically, the developing container 101 has an opening (not shown in numerals) at a position facing the photoreceptor drum 111. A portion of the outer surface of the developing roller 10 is exposed through this opening in the developing container 101. As a result, the outer surface of the developing roller 10 faces the outer surface of the photoreceptor drum 111. The developing roller 10 carries toner on its outer surface and supplies toner to the electrostatic latent image on the outer surface of the photoreceptor drum 111.

[0039] The developing apparatus 100 is equipped with two agitation screws 20. Each agitation screw 20 is positioned inside the developing container 101. Each agitation screw 20 is supported so as to be rotatable around an axis extending in the X direction. Each agitation screw 20 has a structure in which blades are spirally wound around its axis of rotation. The developer is agitated as each agitation screw 20 rotates.

[0040] <Developing roller configuration> The configuration of the developing roller 10 will be explained in detail below with reference to Figures 4 to 6. In the following explanation, the X direction, which is the direction in which the central axis Ac (rotation axis) of the developing roller 10 extends, will be referred to as the axial direction, and the direction perpendicular to the central axis Ac will be referred to as the radial direction. Furthermore, within the axial direction, the direction approaching the center of the developing roller 10 will be referred to as the axial inward direction, and the direction moving away from the center of the developing roller 10 will be referred to as the axial outward direction. Within the radial direction, the direction approaching the central axis Ac will be referred to as the radial inward direction, and the direction moving away from the central axis Ac will be referred to as the radial outward direction.

[0041] The developing roller 10 includes a shaft 1. The shaft 1 is a round bar and extends in the axial direction. That is, the axial direction corresponds to a "predetermined direction". The central axis of the shaft 1 becomes the central axis Ac of the developing roller 10. The shaft 1 has a D-cut surface at one end in the axial direction and is fixed so as not to rotate.

[0042] The developing roller 10 is equipped with a magnet 2. The magnet 2 is fixed to the outer circumferential surface of the shaft 1. The magnet 2 extends in the axial direction. The magnet 2 has multiple magnetic poles in the circumferential direction of the shaft 1.

[0043] The developing roller 10 is equipped with a sleeve 3. The sleeve 3 is made of aluminum. The sleeve 3 is cylindrical in shape with the shaft 1 as its central axis. The central axis Ac of the developing roller 10 coincides with the central axis of the sleeve 3. The shaft 1 is inserted inside the sleeve 3. That is, the magnet 2 is positioned inside the sleeve 3. In this state, the inner circumferential surface of the sleeve 3 and the magnet 2 face each other with a radial gap between them. Also, the outer circumferential surface of the sleeve 3 becomes the outer circumferential surface of the developing roller 10.

[0044] Sleeve 3 carries developer (toner) on its outer surface. The magnetic force of magnet 2 causes the developer to be carried on the outer surface of sleeve 3, forming a magnetic brush on the outer surface of sleeve 3. Sleeve 3 rotates with the developer carried on its outer surface, supplying the developer to the photoreceptor drum 111.

[0045] The developing roller 10 is equipped with a flange 4. The flange 4 is made of aluminum. The flange 4 is fixed to the axial end opening 30 of the sleeve 3.

[0046] The flange 4 has a bearing Br. The inner ring of bearing Br is fixed to the shaft 1, and the outer ring of bearing Br is fixed to the flange 4. This allows the flange 4 to rotatably support the shaft 1. The flange 4 rotates together with the sleeve 3 around its central axis Ac (i.e., around the central axis of the shaft 1).

[0047] One flange 4 is fixed to one axial end opening 30 and the other axial end opening 30 of the sleeve 3. In other words, there are two flanges 4.

[0048] One flange 4 is through which the shaft 1 passes axially. As a result, the end of the shaft 1 with the D-cut surface protrudes to the outside of the sleeve 3. The end of the shaft 1 that protrudes to the outside of the sleeve 3 is clamped, preventing the shaft 1 from rotating. The other flange 4 is connected to a motor (not shown). The other flange 4 rotates around its central axis Ac (i.e., around the central axis of the shaft 1) when driving force is transmitted from the motor.

[0049] Furthermore, the structure of each flange 4 is the same as that of the other flange, except for the presence or absence of a connection to the motor. For convenience, the reference numerals for each flange 4 are the same.

[0050] The developing roller 10 is equipped with an adhesive 5. The adhesive 5 bonds the sleeve 3 and the flange 4. The type of adhesive 5 is not particularly limited. For example, the adhesive 5 is anaerobic. The adhesive 5 does not have to be anaerobic.

[0051] <Flange structure> The following explanation will focus on the structure of one flange 4, referring to Figures 7 and 8. The structures of the two flanges 4 are identical except for the presence or absence of a connection to the motor. Therefore, the explanation of the structure of the other flange 4 will be omitted, as it will be based on the explanation below.

[0052] The flange 4 has a fitting portion 40. The fitting portion 40 is cylindrical in shape. The fitting portion 40 is the part that is positioned inside the sleeve 3. The fitting portion 40 is fitted inside the sleeve 3 through the end opening 30 of the sleeve 3. The fitting portion 40 is inserted into the inside of the sleeve 3 from the axial outward direction. By fitting the fitting portion 40 inside the sleeve 3, the flange 4 is fixed to the end opening 30 of the sleeve 3.

[0053] The flange 4 has a flange portion 400. The flange portion 400 is located axially outward from the fitting portion 40. The flange portion 400 protrudes radially outward from the fitting portion 40 along the entire circumference of the flange 4.

[0054] The outer diameter of the flange portion 400, as viewed from the axial direction, is larger than the maximum outer diameter of the fitting portion 40, as viewed from the axial direction. Therefore, the fitting portion 40 is inserted into the inside of the sleeve 3 until the axially inward-facing surface of the flange portion 400 (hereinafter referred to as the axially inward surface) contacts the axially outward-facing surface of the sleeve 3 (hereinafter referred to as the axial end surface). In other words, the axial end surface of the sleeve 3 contacts the radially inward surface of the flange portion 400. This suppresses axial displacement of the sleeve 3.

[0055] The fitting portion 40 has a first fitting portion 41. The first fitting portion 41 contacts the inner circumferential surface of the sleeve 3. The fitting portion 40 also has a second fitting portion 42. The second fitting portion 42 is the part of the fitting portion 40 that is located axially outward from the first fitting portion 41. The second fitting portion 42 has the same outer diameter as the first fitting portion 41. Therefore, together with the first fitting portion 41, the second fitting portion 42 contacts the inner circumferential surface of the sleeve 3 on the end opening 30 side of the sleeve 3, compared to the first fitting portion 41.

[0056] The first fitting portion 41 and the second fitting portion 42 are the parts of the fitting portion 40 with the largest outer diameter when viewed from the axial direction. The outer diameters of the first fitting portion 41 and the second fitting portion 42 are larger than the inner diameter of the sleeve 3. For this reason, the fitting portion 40 is press-fitted into the inside of the sleeve 3.

[0057] The fitting portion 40 has a relief groove portion 401. The relief groove portion 401 is formed in the axial direction between the second fitting portion 42 and the flange portion 400. The relief groove portion 401 is a portion that is recessed radially inward relative to the outer circumferential surfaces of the first fitting portion 41 and the second fitting portion 42. That is, the relief groove portion 401 is a portion with a smaller outer diameter than the first fitting portion 41 and the second outer circumferential surface. The relief groove portion 401 is continuous with the fitting portion 40 in the circumferential direction without any breaks.

[0058] By providing a relief groove 401 in the fitting portion 40, the fitting portion 40 can be inserted into the inside of the sleeve 3 until the axial end face of the sleeve 3 and the axially inward surface of the flange portion 400 come into contact. This allows the axial end face of the sleeve 3 and the axially inward surface of the flange portion 400 to be in close contact.

[0059] Furthermore, the fitting portion 40 has a groove portion 43. The groove portion 43 is formed in the axial direction between the first fitting portion 41 and the second fitting portion 42. The groove portion 43 is a portion that is recessed radially inward with respect to the outer circumferential surfaces of the first fitting portion 41 and the second fitting portion 42. That is, the groove portion 43 is a portion with a smaller outer diameter than the first fitting portion 41 and the second outer circumferential surface. The groove portion 43 is adjacent to the first fitting portion 41 on the axially inward side and adjacent to the second fitting portion 42 on the axially outward side. The groove portion 43 is continuous without breaks in the circumferential direction of the fitting portion 40.

[0060] The adhesive 5 is placed in the groove 43 (see Figure 6). In other words, the adhesive 5 is placed radially between the sleeve 3 and the flange 4. The adhesive 5 hardens radially between the sleeve 3 and the flange 4, thereby fixing the flange 4 to the sleeve 3.

[0061] The groove 43 has a first groove 431 and a second groove 432. The first groove 431 and the second groove 432 are formed in this order, continuously in the axial direction from the first fitting portion 41 side (i.e., the axially inward side) to the second fitting portion 42 side (i.e., the axially outward side). In other words, the first groove 431 is axially adjacent to the first fitting portion 41 on its axially inward side. The second groove 432 is axially adjacent to the second fitting portion 42 on its axially outward side. The first groove 431 and the second groove 432 are axially adjacent to each other.

[0062] In this embodiment, the radial height H2 from the bottom surface of the second groove 432 to the outer circumferential surface of the first fitting portion 41 is greater than the radial height H1 from the bottom surface of the first groove 431 to the outer circumferential surface of the first fitting portion 41. In other words, the radial depth from the outer circumferential surface of the first fitting portion 41 to the bottom surface of the second groove 432 is greater than the radial depth from the outer circumferential surface of the first fitting portion 41 to the bottom surface of the first groove 431.

[0063] The radial height H1 from the bottom surface of the first groove 431 to the outer circumferential surface of the first fitting portion 41 is 0.10 mm or more and 0.50 mm or less. The radial height H2 from the bottom surface of the second groove 432 to the outer circumferential surface of the first fitting portion 41 is 0.20 mm or more and 0.55 mm or less. However, height H2 is higher than height H1 within the range of 0.20 mm or more and 0.55 mm or less. For example, if height H1 is 0.10 mm, then height H2 is 0.2 mm or more and 0.55 mm or less. If height H1 is 0.50 mm, then height H2 is 0.55 mm.

[0064] Furthermore, the optimal value of the radial height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41 changes depending on the type of adhesive 5. For example, when an anaerobic adhesive is used as the adhesive 5, the radial height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41 is set to 0.20 mm or more and 0.50 mm or less.

[0065] In this embodiment, by configuring the groove 43 in which the adhesive 5 is placed with the first groove 431 and the second groove 432, it is possible to suppress the adhesive 5 from overflowing onto the outer surface of the sleeve 3 when manufacturing the developing roller 10. A detailed explanation follows below.

[0066] The manufacturing process for the developing roller 10 includes at least an adhesive application step and a flange press-fitting step. The flange press-fitting step is performed after the adhesive application step.

[0067] In the adhesive application process, adhesive 5 is applied only to the first groove 431. The amount of adhesive applied to the first groove 431 is set to a volume of 40% to 100% of the spatial volume defined by the inner surface of the first groove 431 and the inner circumferential surface of the sleeve 3.

[0068] In the flange press-fitting process, the fitting portion 40 is press-fitted into the inside of the sleeve 3 with adhesive 5 applied to the first groove 431. At this time, some of the adhesive 5 flows outward in the axial direction from the first groove 431. However, there is a second groove 432 that is radially deeper than the first groove 431, located axially outward from the first groove 431. Therefore, even if some of the adhesive 5 flows outward in the axial direction from the first groove 431, that adhesive 5 accumulates in the second groove 432. This makes it difficult for the adhesive 5 to spill out onto the outer surface of the sleeve 3.

[0069] Here, the outer surface of sleeve 3 becomes the surface on which the developer supplied to the electrostatic latent image on the outer surface of photoreceptor drum 111 is carried. In other words, the developer on the outer surface of sleeve 3 is used to develop the electrostatic latent image into a toner image. Therefore, if adhesive 5 protrudes onto the outer surface of sleeve 3, image defects will occur. To suppress such problems, an adhesive removal step is required to remove the adhesive 5 from the outer surface of sleeve 3. However, even with the addition of the adhesive removal step, it may not be possible to completely remove the adhesive 5 from the outer surface of sleeve 3. Furthermore, adding the adhesive removal step leads to increased costs.

[0070] If adhesive 5 is not used, no problems will occur due to leakage of adhesive 5. However, the fixing strength between sleeve 3 and flange 4 will be insufficient.

[0071] On the other hand, in this embodiment, even if the adhesive 5 flows axially outward, it can be accumulated in the second groove 432. This strengthens the fixation between the sleeve 3 and the flange 4 while preventing the adhesive 5 from overflowing onto the outer surface of the sleeve 3.

[0072] Furthermore, in this embodiment, instead of deepening the entire groove 43, only the second groove 432 is deepened, thereby ensuring sufficient adhesive strength between the sleeve 3 and the first groove 431 due to the adhesive 5.

[0073] Furthermore, in this embodiment, since an anaerobic adhesive is used as the adhesive 5, the height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41 is set to 0.20 mm or more and 0.50 mm or less. This reduces the radial gap between the sleeve 3 and the groove 43, thereby ensuring air is blocked. As a result, the adhesive 5 can be reliably cured.

[0074] <Verification experiment> To confirm the above effects, experiments 1 to 6 were conducted. The results are shown in Figures 9 to 14. In confirmation experiments 1 to 6, adhesive 5 was applied to the first groove 431 of the flange 4, and the fitting portion 40 of the flange 4 was fitted to the inside of the sleeve 3 (hereinafter simply referred to as the fitting process). The excess of adhesive 5 onto the outer surface of the sleeve 3 was then confirmed. The adhesive strength between the sleeve 3 and the flange 4 due to adhesive 5 was also confirmed.

[0075] In verification experiments 1-6, the sleeve 3 and flange 4 are made of aluminum. The inner diameter of the part of the sleeve 3 into which the flange 4 is fitted is 18.4 mm. The outer diameters of the first fitting part 41 and the second fitting part 42 of the fitting part 40 of the flange 4 (i.e., the maximum diameter of the fitting part 40) are 19.0 mm. The adhesive 5 is an anaerobic adhesive (Henkel Japan Ltd., LOCTITE 648).

[0076] In verification experiment 1 (1-1 to 1-9), as shown in Figure 9, the radial height H1 from the bottom surface of the first groove 431 to the outer surface of the first fitting portion 41 was set to 0.15 mm. In verification experiment 2 (2-1 to 2-9), as shown in Figure 10, the height H1 was set to 0.10 mm. In verification experiment 3 (3-1 to 3-9), as shown in Figure 11, the height H1 was set to 0.05 mm. In verification experiment 4 (4-1 to 4-9), as shown in Figure 12, the height H1 was set to 0.40 mm. In verification experiment 5 (5-1 to 5-9), as shown in Figure 13, the height H1 was set to 0.45 mm. In verification experiment 6 (6-1 to 6-9), as shown in Figure 14, the height H1 was set to 0.50 mm.

[0077] Furthermore, in confirmation experiments 1 to 6, the radial height H2 from the bottom surface of the second groove 432 to the outer circumferential surface of the first fitting portion 41 was varied within the range of 0.10 mm to 0.55 mm.

[0078] Furthermore, in the experiment to check for excess adhesive 5, the amount of adhesive 5 applied to the first groove 431 was set to 100% of the volume of the space defined by the inner surface of the first groove 431 and the inner circumferential surface of the sleeve 3. In the experiment to check the adhesive strength provided by the adhesive 5, the amount of adhesive 5 applied to the first groove 431 was set to 40% of the volume of the space defined by the inner surface of the first groove 431 and the inner circumferential surface of the sleeve 3.

[0079] In the experiment to check for excess adhesive 5, the fitting process of the flange 4 to the sleeve 3 was performed 10 times for each of experiments 1-1 to 6-9. That is, the number of samples for each of experiments 1-1 to 6-9 was 10. Then, a black light was shone on the end of the sleeve 3 to check whether or not adhesive 5 had oozed out. Here, for each of experiments 1-1 to 6-9, the ratio of the number of samples with excess adhesive 5 to the total number of samples (10) was calculated. The results are shown in the "Oozing" column of Figures 9 to 14. An "Oozing" of 100% means that there was excess adhesive 5 in all 10 samples. An "Oozing" of 50% means that there was excess adhesive 5 in 5 out of 10 samples.

[0080] In the experiment to confirm the adhesive strength of adhesive 5, after the fitting process of the flange 4 to the sleeve 3 was performed, the torque between the sleeve 3 and the flange 4 was measured using an opening torque measuring device. The results are shown in the "Adhesive Strength" column of Figures 9 to 14. If the measured torque is less than 1.96 N·m, the adhesive strength is weak. If the measured torque is 1.96 N·m or more, the adhesive strength is strong and is indicated by a circle. If the measured torque is 10 N·m or more, it is indicated by a double circle. Note that an adhesive strength of 1.96 N·m or more is sufficient.

[0081] Furthermore, after the fitting process of the flange 4 to the sleeve 3, it was checked whether there were any uncured portions in the adhesive 5. If there are any uncured portions in the adhesive 5, there is a possibility that those portions will ooze out, so it is preferable that there are no uncured portions in the adhesive 5.

[0082] The results of confirmation experiment 1 (1-1 to 1-9) showed that when the radial height H1 from the bottom surface of the first groove 431 to the outer surface of the first fitting portion 41 was 0.15 mm, and the radial height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41 was higher than height H1, between 0.20 mm and 0.55 mm, the adhesive 5 did not overflow. On the other hand, when height H1 was 0.15 mm and height H2 was 0.15 mm or less, the adhesive 5 overflowed. However, when height H2 was 0.15 mm (50%), the overflow of adhesive 5 was suppressed more than when height H2 was 0.10 mm (100%).

[0083] The results of confirmation experiment 2 (2-1 to 2-9) showed that when the radial height H1 from the bottom surface of the first groove 431 to the outer surface of the first fitting portion 41 was 0.10 mm, and the radial height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41 was higher than height H1, between 0.20 mm and 0.55 mm, it was confirmed that the adhesive 5 did not overflow. On the other hand, when height H1 was 0.10 mm and height H2 was 0.15 mm or less, it was confirmed that the adhesive 5 overflowed. However, when height H2 was 0.15 mm (50%), the overflow of adhesive 5 was suppressed more than when height H2 was 0.10 mm (100%).

[0084] The results of confirmation experiment 3 (3-1 to 3-9) confirmed that when the radial height H1 from the bottom surface of the first groove 431 to the outer surface of the first fitting portion 41 is 0.05 mm, the adhesive 5 will ooze out regardless of the radial height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41.

[0085] The results of confirmation experiment 4 (4-1 to 4-9) showed that when the radial height H1 from the bottom surface of the first groove 431 to the outer surface of the first fitting portion 41 is 0.40 mm, and the radial height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41 is higher than height H1, between 0.45 mm and 0.55 mm, the adhesive 5 does not overflow. On the other hand, when height H1 is 0.40 mm and height H2 is 0.40 mm or less, the adhesive 5 overflows.

[0086] The results of confirmation experiment 5 (5-1 to 5-9) showed that when the radial height H1 from the bottom surface of the first groove 431 to the outer surface of the first fitting portion 41 is 0.45 mm, and the radial height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41 is higher than height H1, between 0.50 mm and 0.55 mm, the adhesive 5 does not overflow. On the other hand, when height H1 is 0.45 mm and height H2 is 0.45 mm or less, the adhesive 5 overflows.

[0087] The results of confirmation experiment 6 (6-1 to 6-9) confirmed that when the radial height H1 from the bottom surface of the first groove 431 to the outer surface of the first fitting portion 41 is 0.50 mm, and the radial height H2 from the bottom surface of the second groove 432 to the outer surface of the first fitting portion 41 is 0.55 mm (higher than height H1), the adhesive 5 does not overflow. On the other hand, when the height H1 is 0.50 mm and the height H2 is 0.50 mm or less, the adhesive 5 overflows.

[0088] These results suggest that by setting the height H1 to between 0.10 mm and 0.50 mm, and the height H2 to be higher than height H1 within the range of 0.20 mm and 0.55 mm, the overflow of adhesive 5 can be suppressed.

[0089] Furthermore, the results of confirmation experiments 1 to 6 confirmed that adhesive strength can be ensured by adhesive 5 when height H1 is between 0.10 mm and 0.50 mm, and height H2 is higher than height H1 within the range of 0.20 mm to 0.55 mm. However, the adhesive strength by adhesive 5 is slightly weaker than when height H2 is 0.15 mm or less. However, if height H2 is 0.15 mm or less, adhesive 5 will ooze out, so it is preferable to set height H2 to 0.20 mm or more.

[0090] Furthermore, when the height H2 was 0.55 mm, a portion of the adhesive 5 remained uncured regardless of the height H1. Therefore, when using an anaerobic adhesive as the adhesive 5, it is preferable to set the height H2 to between 0.20 mm and 0.50 mm.

[0091] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and furthermore, all modifications within the meaning and scope equivalent to the claims are included. [Explanation of Symbols]

[0092] 1 shaft 2 Magnets 3 sleeves 4 flanges 5. Adhesive 10. Developing roller (developer carrier) 30 End opening 40 Fitting part 41 First mating section 42 Second fitting section 43 Groove 431 First groove 432 Second groove Ac central axis

Claims

1. A shaft extending in a predetermined direction, A magnet fixed to the outer surface of the shaft, The aforementioned shaft has a cylindrical shape with the shaft as its central axis, and the sleeve supports the developer on its outer surface, A flange fixed to the end opening of the sleeve in the predetermined direction and rotatably supported on the shaft, which rotates together with the sleeve around the central axis, The system includes an adhesive for bonding the sleeve and the flange, The flange has a cylindrical fitting portion that is fitted to the inside of the sleeve through the end opening, The aforementioned fitting portion is, A first fitting portion that contacts the inner circumferential surface of the sleeve, A second fitting portion has the same outer diameter as the first fitting portion and contacts the inner circumferential surface of the sleeve at a position closer to the end opening than the first fitting portion, It has a groove formed between the first fitting portion and the second fitting portion in the predetermined direction, which is recessed radially with respect to the outer circumferential surfaces of the first fitting portion and the second fitting portion, The adhesive is placed in the groove, The groove portion has a first groove portion and a second groove portion, The first groove and the second groove are formed in this order, continuously in the predetermined direction from the first fitting portion side toward the second fitting portion side. A developer carrier wherein the height from the bottom surface of the second groove to the outer circumferential surface of the first fitting portion is greater than the height from the bottom surface of the first groove to the outer circumferential surface of the first fitting portion.

2. The developer carrier according to claim 1, wherein the height from the bottom surface of the first groove to the outer circumferential surface of the first fitting portion is 0.10 mm or more and 0.50 mm or less, and the height from the bottom surface of the second groove to the outer circumferential surface of the first fitting portion is in the range of 0.20 mm or more and 0.55 mm or less, and is higher than the height from the bottom surface of the first groove to the outer circumferential surface of the first fitting portion.

3. In the case where the adhesive is an anaerobic adhesive, the height from the bottom surface of the second groove to the outer circumferential surface of the first fitting portion is set to 0.20 mm or more and 0.50 mm or less, as described in claim 2.

4. A method for producing a developer carrier according to any one of claims 1 to 3, The steps include applying the adhesive to the first groove and A method for manufacturing a developer carrier, comprising the step of press-fitting the fitting portion into the inside of the sleeve through the end opening while the adhesive is applied to the first groove.

5. The method for manufacturing a developer carrier according to claim 4, wherein the amount of adhesive applied to the first groove is set to a volume of 40% or more and 100% or less of the spatial volume defined by the inner surface of the first groove and the inner circumferential surface of the sleeve.

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