Developing device

Abstract

To reduce leakage of developer from a developer frame body, while maintaining a uniform thickness of a developer layer in a developer coat area on a developing roller, when a layer thickness regulation blade is fixed by welding.SOLUTION: A regulation blade has: a support plate that is fixed to a developer frame body; a plate-like member that faces a developing member at one end and is welded to the support plate at the other end, and is formed with concave parts in each of which an end in a rotation axis direction is recessed compared to a center part in a direction from one end toward the other end; and seal members that are each arranged at the end on the outside of the concave part separated from the center part, and perform sealing to prevent leakage of developer. An area of the plate-like member is on the other end side and overlaps the center part of the plate-like member and the ends where the concave parts are formed and the seal members are arranged. At the end, a welding trace is formed continuously from an area of the plate-like member overlapping the concave part and not overlapping the position of the seal member to an area of the plate-like member overlapping the position of the seal member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a developing device used in an image forming apparatus. [Background technology]

[0002] The following configuration is used as a developing device for use in an image forming apparatus: Patent Document 1 discloses a developing device including a rotatable developing roller and a layer thickness regulating blade that contacts the peripheral surface of the developing roller.

[0003] In the developing device described in Patent Document 1, the layer thickness regulating blade is composed of a blade that regulates the layer thickness and a support member that supports the blade, and the blade and the support member are fixed by welding. Patent Document 1 discloses a configuration in which the blade and the support member are not welded to each other at the blade end in the rotational axis direction of the developing roller. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-133768 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the configuration of Patent Document 1 had the following problems. In the welding range of the layer thickness regulating blade, the contact pressure of the blade end is reduced by not welding the blade end, which may cause the developer to easily leak out of the developing frame. If the developer leaks outside the developing device, it may soil the developing device.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to reduce leakage of developer from the developing frame while maintaining a uniform developer layer thickness in the developer coated area of ​​the developing roller when a layer thickness regulating blade is fixed by welding. [Means for solving the problem]

[0007] In order to solve the above problems, the developing device according to the present application is a developing device used in an image forming apparatus, and includes a developing frame that contains a developer, a developing member that supports the developer and is rotatable, and a regulating blade that contacts the developing member so as to regulate the layer thickness of the developer on the surface of the developing member. a seal member that seals an end portion of the developing member in a rotation axis direction to prevent the developer from leaking to the outside of the developing frame; , and the regulating blade has before a support plate extending in the direction of the rotation axis and fixed to the developing frame; and a plate-like member extending in the direction of the rotation axis and supported by the support plate. and the regulating blade has One end in a direction intersecting the rotation axis direction In the other end portion facing the developing member in the intersecting direction In the above, the plate-like member A recess is formed at an end portion in the direction of the rotation axis, the end portion being recessed in a direction from the one end portion toward the other end portion relative to a central portion. In front The support plate is welded to the support plate. Regulatory Blade The area of ,before In the direction of the rotation axis Regulatory Blade and the end portion where the recess is formed and the seal member is disposed, In the direction of the rotation axis, The end overlaps the recess. The regulating blade The region overlapping the position where the seal member is disposed Regulatory Blade Up to the area of Weld marks across It is characterized in that it is formed. Effect of the Invention

[0008] When the layer thickness regulating blade is fixed by welding, it is possible to reduce leakage of the developer from the developing frame while keeping the developer layer thickness in the developer coated area of ​​the developing roller uniform. [Brief description of the drawings]

[0009] [Figure 1] 5 is a detailed view of a layer thickness regulating blade assembly portion on the driving side of the developing cartridge according to the first embodiment. FIG. [Diagram 2]FIG. 1 is a cross-sectional view of an image forming apparatus according to a first embodiment. [Diagram 3] FIG. 1 is a perspective view of an image forming apparatus according to a first embodiment. [Figure 4] FIG. 2 is a perspective view of a cartridge tray and a developing cartridge according to the first embodiment. [Diagram 5] FIG. 2 is a cross-sectional view of the developing cartridge and the drum unit according to the first embodiment. [Figure 6] FIG. 2 is an exploded perspective view of the developing cartridge according to the first embodiment. [Figure 7] 4 is an explanatory diagram of a fixing portion of the layer thickness regulating blade according to the first embodiment. FIG. [Figure 8] 4 is an explanatory diagram of a fixing portion of the layer thickness regulating blade according to the first embodiment. FIG. [Figure 9] FIG. 11 is an exploded perspective view of a developing cartridge according to a second embodiment. [Figure 10] FIG. 11 is a cross-sectional view of a developing cartridge and a drum unit according to a second embodiment. [Figure 11] FIG. 11 is an explanatory diagram of a developing cartridge according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] With reference to the drawings, the embodiment of the present invention will be described in detail by way of example. However, the functions, materials, shapes, relative positions, etc. of the components described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified. Furthermore, the functions, materials, shapes, etc. of the members once described in the following description are the same as those described in the first description unless otherwise specified.

[0011] In the following description, the direction in which the axis of the developing roller extends is referred to as the "first direction", "longitudinal direction", "rotation axis direction", or "longitudinal". A direction that intersects with the first direction and is a vertical direction when the image forming apparatus is installed on a horizontal surface is referred to as the "second direction". A direction that intersects with the first and second directions is referred to as the "third direction". The first and second directions intersect with each other, preferably perpendicular to each other. The second and third directions intersect with each other, preferably perpendicular to each other. The third direction and the first direction intersect with each other, preferably perpendicular to each other.

[0012] In the following description, the side of the image forming apparatus where the front door is provided is referred to as the front side, and the side opposite the front side is referred to as the rear side. Also, when looking at the image forming apparatus from the front side, the left side is referred to as the driving side, and the right side is referred to as the non-driving side. EXAMPLES

[0013] A developing device according to a first embodiment of the present invention will be described with reference to the drawings.

[0014] <Configuration of Electrophotographic Image Forming Apparatus> First, the configuration of the electrophotographic image forming apparatus will be described. FIG. 2 is a cross-sectional view of an electrophotographic image forming apparatus 1 (hereinafter referred to as "image forming apparatus 1") according to this embodiment. FIG. 3 is a perspective view of the image forming apparatus 1 according to this embodiment, in which FIG. 3(a) is a view showing a state in which the front door 40 of the image forming apparatus 1 is opened and the cartridge tray 3 is pulled out, and FIG. 3(b) is a view in which the cartridge tray 3 is not shown. FIG. 4 is a perspective view of the cartridge tray 3 and the developing cartridge 8, which is a developing device, according to this embodiment. FIG. 5 is a cross-sectional view of the developing cartridge 8 and the drum unit 30, which are developing devices according to this embodiment. The cross-sectional views of FIG. 2 and FIG. 5 are cross-sectional views taken from a direction perpendicular to the rotation axis direction of the developing roller 6, which is a developing member.

[0015] The image forming apparatus 1 shown in FIG. 2 is a color laser printer using an electrophotographic image forming process. It forms a color image on a recording medium S (e.g., printing paper) by a developer (e.g., toner) supplied from a developing cartridge 8 (8Y, 8M, 8C, 8K) which is a developing device. In this embodiment, an example is shown in which a color image is formed by four photosensitive drums 4 (4Y, 4M, 4C, 4K) and four developing cartridges 8 (8Y, 8M, 8C, 8K). The four developing cartridges 8 contain developers of different colors (e.g., yellow, cyan, magenta, and black). The number of developing cartridges 8 and photosensitive drums 4 may be one to three, or may be five or more, depending on the number of colors used. In this embodiment, the configurations and operations of the photosensitive drums 4 (4Y, 4M, 4C, 4K) and the developing cartridges 8 (8Y, 8M, 8C, 8K) are substantially the same except that the colors of the images to be formed are different. Therefore, hereinafter, unless a distinction is particularly required, Y, M, C, and K will be omitted and a general description will be given. That is, in this embodiment, the image forming apparatus 1 has, as a plurality of image carriers, four photosensitive drums 4 arranged side by side in a direction intersecting with the vertical direction, and developing cartridges 8.

[0016] The image forming apparatus 1 is composed of an electrophotographic image forming apparatus main body 2 (hereinafter referred to as the “apparatus main body 2”), a cartridge tray 3 having a photosensitive drum 4 and detachable from the apparatus main body 2, and a developing cartridge 8 detachable from the cartridge tray 3.

[0017] The apparatus main body 2 has an exposure device 10, an electrostatic transfer device 11, a paper feed unit 18, a fixing device 21, a discharge unit 22, and a front door 40.

[0018] The exposure device 10 is provided above the developing cartridges 8 and the cartridge tray 3, and outputs a laser beam L corresponding to image information. The laser beam L scans and exposes the surfaces of the photosensitive drums 4 (4Y, 4M, 4C, and 4K).

[0019] A developing cartridge 8 is provided as a developing device for developing a developer onto the scanned and exposed surface of the photosensitive drum 4. The developing process by which a developer image is formed on the surface of the photosensitive drum 4 will be described later.

[0020] The electrostatic transfer device 11 is provided below the developing cartridge 8 and the cartridge tray 3, and has a transfer belt 12 that moves in a circular motion so as to face and contact all the photosensitive drums 4. The transfer belt 12 is made of a resin film or a multi-layer film-like member in which a resin layer is provided on a rubber base layer. The transfer belt 12 is stretched around a driving roller 13 and a driven roller 14. The transfer belt 12 electrostatically attracts the recording medium S to the outer peripheral surface on the upper side in FIG. 2, and moves in a circular motion so as to bring the recording medium S into contact with the photosensitive drum 4. As a result, the recording medium S is transported toward the photosensitive drum 4. A transfer roller 16 is arranged in parallel at a position that abuts against the inner side of the transfer belt 12 and faces the photosensitive drum 4. A predetermined bias is applied to these transfer rollers 16 during transfer, and an electric charge is applied to the recording medium S via the transfer belt 12. The developer image on the photosensitive drum 4 is transferred to the recording medium S in contact with the photosensitive drum 4 by the electric field generated at this time.

[0021] The paper feed unit 18 is provided below the electrostatic transfer device 11. The paper feed unit 18 has a paper feed tray 19 on which the recording medium S is stacked and stored, and a paper feed roller 20.

[0022] The fixing device 21 and the discharge unit 22 are provided above the apparatus main body 2. The fixing device 21 fixes the developer image transferred onto the recording medium S by applying heat and pressure, and the discharge unit 22 discharges the recording medium S that has passed through the fixing device 21 onto a discharge tray 23.

[0023] The cartridge tray 3 has a drum unit 30 provided with photosensitive drums 4 corresponding to the four developing cartridges 8, respectively. Furthermore, as shown in FIG. 5, the drum unit 30 includes a drum frame 27 and a charging device 5.

[0024] As shown in FIG. 3, the cartridge tray 3 is configured to be capable of being pulled out toward the front side in the third direction along a tray pull-out rail 41 provided on the image forming apparatus 1 after a front door 40 of the image forming apparatus 1 is opened.

[0025] 5, the developer cartridge 8 has a developer frame 28 that contains the developer, and a developer roller 6 that carries the developer on its circumferential surface and is rotatable about a rotation axis extending in the first direction. The developer cartridge 8 also has a supply roller 26 that supplies the developer to the developer roller 6, and a layer thickness regulating blade 72 that contacts the circumferential surface of the developer roller 6 to regulate the thickness of the developer carried on the surface of the developer roller 6.

[0026] As shown in Fig. 4, the developing cartridge 8 is attachable to and detachable from the cartridge tray 3 in the second direction. As an example, Fig. 4 shows a state in which the developing cartridge 8C has been removed from the cartridge tray 3. In this manner, the developing cartridges 8 are attached and detached to and from the four slots provided in the cartridge tray 3, and the developing cartridges 8 can be replaced depending on the usage situation.

[0027] Image formation process Next, the image forming process will be described with reference to FIGS.

[0028] During the image formation process, the photosensitive drum 4 is rotated at a predetermined speed in the direction of arrow D shown in Figs. 2 and 5. The transfer belt 12 of the electrostatic transfer device 11 is also rotated at a speed corresponding to the speed of the photosensitive drum 4 in the direction of arrow C. First, the surface of the photosensitive drum 4 is uniformly charged to a predetermined polarity and potential by the charging device 5. Then, the exposure device 10 outputs laser light L corresponding to the image signal of each color, and scans and exposes the surface of each photosensitive drum 4. As a result, an electrostatic latent image corresponding to the image signal of each color is formed on the surface of each photosensitive drum 4.

[0029] The developer in the developing frame 28 is carried by the developing roller 6 which is driven to rotate in the direction of the arrow E at a predetermined speed as shown in FIG. 5. The developer carried by the developing roller 6 is supplied to the surface of the developing roller 6 by the supply roller 26. The developer supplied to the developing roller 6 enters between the developing roller 6 and the layer thickness regulating blade 72 and is carried on the developing roller 6 as a thin layer of a certain thickness. The developer carried on the developing roller 6 is supplied to the electrostatic latent image formed on the photosensitive drum 4. As a result, the developer adheres to the electrostatic latent image and is developed (visible), forming a developer image on the surface of the photosensitive drum 4. In this embodiment, the polarity of the developer is set to positive. Therefore, a voltage of positive polarity is applied to the developing roller 6 from a development power source (not shown) compared to the potential of the electrostatic latent image formed on the surface of the photosensitive drum 4. By setting as above, the positively charged developer moves from the developing roller 6 to the electrostatic latent image formed on the photosensitive drum 4.

[0030] Also, the recording medium S is separated and fed one by one at a predetermined control timing. The leading edge of the developer image on the peripheral surface of the first photosensitive drum 4Y of the recording medium S moves to the transfer section, which is the opposing point to the transfer belt 12. Then, the timing at which the recording medium S is conveyed to the transfer section is synchronized with the rotation of the photosensitive drum 4, and the recording medium S is conveyed to the transfer belt 12 at a predetermined control timing so that the printing start position coincides at the transfer section. The developer images of each photosensitive drum 4 are sequentially transferred to the recording medium S conveyed by electrostatic adsorption to the transfer belt 12 by the electric field formed between each photosensitive drum 4 and the transfer roller 16. At this time, a negative voltage, which is the opposite polarity to the positive polarity, is applied to the transfer roller 16 from a transfer power source (not shown). This makes it possible to electrically attract the positive developer to the recording medium S side.

[0031] The recording medium S onto which the four-color developer images have been transferred is separated from the transfer belt 12 and conveyed to the fixing device 21. The developer images are thermally fixed onto the recording medium S by the fixing device 21. Thereafter, the recording medium S is discharged to a discharge tray 23 by a discharge unit 22.

[0032] Furthermore, the developer remaining on the photosensitive drum 4 without being transferred is collected in the developing cartridge 8 and reused. Specifically, the photosensitive drum 4 is once positively charged by the charging device 5, and the surface potential of the photosensitive drum 4 is made higher on the positive side than the voltage applied to the developing roller 6. As a result, when the residual developer positively charged on the surface of the photosensitive drum 4 moves to the portion facing the developing roller 6, the residual developer is electrically collected inside the developing frame 28.

[0033] <Details of the drum unit and developing cartridge> The detailed configurations of the drum unit 30 and the developing cartridge 8 will be described with reference to Figures 5 and 6. Figure 6 is an exploded perspective view of the developing cartridge 8, with the mounting directions of the various parts indicated by arrows.

[0034] As shown in FIG. 5, the drum unit 30 includes the photosensitive drum 4, the drum frame 27, and the charging device 5 as described above. The photosensitive drum 4 is attached to the drum frame 27 so as to be rotatable about a rotation axis extending in the first direction. In addition, a drum input coupling 54 for transmitting a driving force to the photosensitive drum 4 is provided on the driving side of the photosensitive drum 4 (FIG. 4). The drum input coupling 54 is configured to receive a driving force from the device body 2 and transmit it to the photosensitive drum 4 by engaging with a drum driving coupling 52 (FIG. 3(b)) of the device body 2. The charging device 5 is provided along the first direction and is supported by the drum frame 27 in close proximity to the photosensitive drum 4. The charging device 5 is electrically connected to the device body 2.

[0035] As described above, the developer cartridge 8 has the developing frame 28 that contains the developer, the developing roller 6, the supply roller 26 that supplies the developer to the developing roller 6, and the layer thickness regulating blade 72 that regulates the thickness of the developer carried on the surface of the developing roller 6. As shown in Fig. 6, the developer cartridge 8 also has a fixing screw 99, an agitating member 88, a driving side bearing member 70, a side cover 68, and a non-driving side bearing member 71. In addition, the developer cartridge 8 has a developing gear 61, a supply gear 63, a developing input gear 62, an agitating gear 65, and an idler gear 64 for driving each member of the developer cartridge 8. Details will be described later.

[0036] The developing roller 6 is a roller that can rotate in the direction of the arrow E on a rotation axis extending in the first direction, as shown in FIG. 5, and is composed of a roller body and a roller shaft. The roller body is made of, for example, rubber or a sponge member having elasticity. The roller shaft is made of, for example, metal or resin having electrical conductivity. A developing gear 61 is connected to the drive side end of the roller shaft. The supply roller 26 contacts the developing roller 6 to supply developer to the surface of the developing roller 6, and is rotatable on the rotation axis extending in the first direction. The supply roller 26 is composed of a roller body and a roller shaft, and the roller body is made of, for example, rubber or a sponge member having elasticity. The roller shaft is made of, for example, metal or resin having electrical conductivity. A supply gear 63 is connected to the drive side end of the roller shaft.

[0037] The layer thickness regulating blade 72 comes into contact with the developing roller 6 and regulates the thickness of the developer carried on the surface of the developing roller 6. This layer thickness regulating blade 72 is composed of a support plate 73 and a blade portion 74 made of a plate-like member, and is fixed at the position of a fixed portion W. The detailed structure of the layer thickness regulating blade 72 will be described later.

[0038] The developing frame 28 accommodates the developer therein, and has a blade support surface 28a facing the support plate 73 of the layer thickness regulating blade 72, and a fixing hole 28b provided in the blade support surface 28a.

[0039] The developing frame 28 has a positioning rib 28c at a position corresponding to the positioning groove 73d of the support plate 73 of the layer thickness regulating blade 72, and rotatably supports the stirring gear 65 and one end of the idler gear 64.

[0040] The developing frame 28 and the layer thickness regulating blade 72 are fixed at both ends by abutting the blade support surface 28a against the support plate 73 and engaging the positioning rib 28c with the positioning groove 73d, and then fastening a fixing screw 99 through the through hole 73c into the fixing hole 28b.

[0041] Furthermore, a first seal member 76 is provided between the developing frame 28 and the layer thickness regulating blade 72 in the direction of the rotation axis of the developing roller 6 (first direction), and second seal members 77 are provided at both ends in the first direction. The first seal member 76 and the second seal member 77 are members including a flexible member such as a sponge, and are compressed between the developing frame 28 and the layer thickness regulating blade 72 to fill the gap and suppress leakage of the developer. The developer sealing configuration of the layer thickness regulating blade 72 and the second seal member 77 will be described in detail later.

[0042] 5, a third seal member 78 is provided on the developing frame 28 across the first direction. The third seal member 78 is a flexible sheet-like member made of a material such as PET, PPS, or PC, and is configured such that one end is attached to the developing frame 28 and the other end is in contact with the developing roller 6 in a direction perpendicular to the first direction. The third seal member 78 flexes to fill the gap between the developing frame 28 and the developing roller 6, thereby preventing leakage of developer.

[0043] Further, a shatterproof sheet 79 is provided across the first direction near the third seal member 78. In a direction perpendicular to the first direction, one end of the shatterproof sheet 79 is attached to the developing frame 28, and the other end extends so as to approach the developing roller 6. The shatterproof sheet 79 receives the developer that has fallen from near the developing roller 6, thereby preventing the developer from scattering to the outside.

[0044] As shown in FIG. 5, the agitating member 88 is provided inside the developing frame 28 and is composed of a shaft portion 88a that is rotatable on a rotation axis extending in the first direction, and a flexible sheet-like sheet portion 88b. The agitating member 88 agitates the developer in the developing frame 28 and conveys the developer toward the supply roller 26. As shown in FIG. 6, the agitating gear 65 is connected to the drive side end of the shaft portion 88a. The drive side bearing member 70 is fixed to the developing frame 28 on the drive side, and rotatably supports the roller shaft of the developing roller 6, the roller shaft of the supply roller 26, and the developing input gear 62. The side cover 68 is fixed to the developing frame 28 on the drive side, and rotatably supports the other end of the idler gear 64, and has a function of covering and protecting the supply gear 63, the developing input gear 62, the idler gear 64, and the agitating gear 65. The side cover 68 has a through hole 68a at a position corresponding to the development input gear 62, and exposes a coupling portion 62a of the development input gear 62 after assembly. The non-drive side bearing member 71 is fixed to the developing frame 28 on the non-drive side, and rotatably supports the roller shaft of the development roller 6 and the roller shaft of the supply roller 26. The development input gear 62 has a coupling portion 62a for receiving a driving force by engaging with the development drive coupling 51 (FIG. 3(b)) of the apparatus main body 2. The driving force input to the development input gear 62 is transmitted to the development roller 6 via the development gear 61, to the supply roller 26 via the supply gear 63, and to the stirring member 88 via the idler gear 64 and the stirring gear 65.

[0045] <Details of the layer thickness regulation blade> The detailed configuration of the layer thickness regulating blade 72 will be described with reference to FIGS.

[0046] Fig. 1 is a detailed view of an assembly portion of a layer thickness regulating blade 72 on the drive side of a developer cartridge 8. Furthermore, Fig. 1(a) is a detailed view of a state in which the developer roller 6 is assembled, and Fig. 1(b) is a detailed view of a state in which the developer roller 6 is represented by a dashed line.

[0047] As shown in FIG. 1 and FIG. 6, the support plate 73 of the layer thickness regulating blade 72 is a metal member that supports the blade portion 74. The support plate 73 has a first plate-shaped portion 73a that is substantially rectangular and extends in the first direction facing the blade portion 74, and a second plate-shaped portion 73b that extends from the first plate-shaped portion 73a in a direction intersecting the blade portion 74. The first plate-shaped portion 73a has protruding portions 73e at both ends in the first direction that protrude in a direction perpendicular to the first direction and away from the developing roller 6, and the protruding portions 73e are provided with through holes 73c that penetrate in the thickness direction. The second plate-shaped portion 73b is provided with a positioning groove 73d that is elongated and groove-shaped. As shown in FIG. 1 and FIG. 6, the blade portion 74 of the layer thickness regulating blade 72 is a metal member that is substantially rectangular and extends in the first direction. The blade 74 has a first regulating portion 74a and a second regulating portion 74e, which are one end side that contacts the peripheral surface of the developing roller 6 in a direction intersecting with the first direction, and a base end portion 74b, which is the other end fixed to the first plate-shaped portion 73a of the support plate 73. The blade 74 has a thickness that allows elastic deformation when it abuts against the developing roller 6. The blade 74 abuts against the developing roller 6 by utilizing the restoring force generated during elastic deformation, and the thickness of the developer carried on the surface of the developing roller 6 is regulated by the first regulating portion 74a and the second regulating portion 74e. A connecting portion 74f is provided as a portion that connects the first regulating portion 74a and the second regulating portion 74e. Here, the connecting portion 74f is an inclined straight line. Here, the first regulating portion 74a regulates the layer thickness within a range that is required to ensure image performance as an electrophotographic image forming apparatus, and the second regulating portion 74e prevents the developer from leaking out of the developing frame 28 from the second seal member 77. Therefore, the developer layer is restricted to a thickness sufficient for sealing the developer in. The first restricting portion 74a, the second restricting portion 74e, and the connecting portion 74f will be described in detail later.

[0048] In addition, a round hole 74c and an elongated hole 74d are formed at both ends of the blade portion 74 in the first direction, and a round hole 73f and an elongated hole 73g are also formed at corresponding positions of the first plate-shaped portion 73a of the support plate 73. When the blade portion 74 is fixed to the support plate 73, the round holes 74c and 73f, the elongated holes 74d and 73g are positioned at the through-hole positions by an assembly jig and then fixed. This improves the positioning accuracy of the relative positions of the support plate 73 and the blade portion 74. In this embodiment, a hole shape is provided in each of the support plate 73 and the blade portion 74, but the shape of one of the parts may be a hole and the shape of the other part may be a protrusion, and the relative positions between the parts may be regulated by engaging the hole and the protrusion with each other.

[0049] In this embodiment, the blade portion 74 is fixed to the support plate 73 by laser welding, which has a high fixing strength while reducing the area of ​​the fixing portion W. The fixing length (fixing length) of the fixing portion W in the first direction needs to be a fixing length corresponding to the layer thickness restrictions of the first restricting portion 74a and the second restricting portion 74e described above. The fixing portion W and the fixing length will be described in detail later.

[0050] Here, as a fixing method other than the laser welding in this embodiment, a fixing method using an adhesive or double-sided tape can be mentioned.

[0051] In the case of using an adhesive, when the end position (longitudinal end position) in the first direction of the fixing portion W is limited as in this embodiment, the following problems occur, and this is not a preferable fixing method in this embodiment. When the range of the first restricting portion 74a is fixed and the range of the second restricting portion 74e is limited so as not to be fixed, there is a risk that the adhesive may overflow onto the second restricting portion 74e side during assembly depending on the viscosity of the adhesive. Furthermore, since the application position must be determined taking into consideration that the adhesive will spread during bonding, there is a risk that the adhesive strength will become uneven. Furthermore, it is necessary to provide time for drying during assembly, and to provide air conditioning equipment so that volatile components released from the adhesive during drying do not affect other parts, and this is significantly inferior in functionality to laser welding fixation.

[0052] In addition, when the double-sided tape is used as the fixing method, if the longitudinal end position of the fixing portion W is limited as in this embodiment, the following problems occur, and this is not preferable as the fixing method in this embodiment. A gap may occur between the support plate 73 and the blade portion 74 due to the thickness difference of the double-sided tape, and the developer may leak out. In order to prevent the developer from leaking, a further sealing structure is required. Furthermore, when the double-sided tape is applied, wrinkles and stretched portions may occur in the double-sided tape. Here, if there are wrinkles, the developer may leak due to a small step, or unevenness may occur in the regulating pressure on the developing roller 6, resulting in unevenness in the layer thickness of the developer, which affects the image. If there are stretched portions, the adhesion area is reduced, and the adhesive strength between the support plate 73 and the blade portion 74 is weakened. If unevenness in the adhesive strength occurs, unevenness may occur in the regulating pressure on the developing roller 6, resulting in unevenness in the layer thickness of the developer, which affects the image. Furthermore, since the double-sided tape is attached with a release paper, a processing process is required to discard the release paper when the double-sided tape is peeled off during assembly. Therefore, it is extremely difficult to employ a double-sided tape as the fixing method in this embodiment.

[0053] In addition, depending on the production volume of the layer thickness regulating blades 72, adhesives and double-sided tapes may be more expensive than laser welding equipment.

[0054] For the above reasons, in this embodiment, laser welding is adopted for the purpose of shortening the process time, reducing costs, and improving functionality.

[0055] <Developer layer thickness regulation by layer thickness regulating blade> 1, the developer layer thickness regulation by the layer thickness regulating blade 72 will be described. The range of the developer layer thickness regulation by the layer thickness regulating blade 72 is determined by the fixing portion W that fixes the support plate 73 and the blade portion 74 by welding, and the arrangement of the first regulating portion 74a and the second regulating portion 74e.

[0056] The fixing portion W is preferably disposed as close as possible to the base end 74b in the direction intersecting the first direction, taking into consideration the performance of the laser welding device and the component precision of the support plate 73 and the blade portion 74. If it is disposed farther away from the base end 74b, the support plate 73 to be fixed by welding must also be extended at the same time, resulting in an increase in material costs and an increase in size of the developing cartridge 8 and the electrophotographic image forming apparatus 1. The end position (longitudinal end position) of the fixing portion W in the first direction is preferably disposed at least longitudinally outward of the end face of the longitudinal inner end 77a of the second seal member 77 in the first direction. The fixing end will be described in detail below together with the first regulating portion 74a and the second regulating portion 74e.

[0057] In this embodiment, the definitions of "inner side" and "outer side" are as follows: the side closer to the center of the developing roller 6 and the layer thickness regulating blade 72 in the direction of the rotation axis of the developing roller 6 is the "inner side", and the side farther from the center of the developing roller 6 and the layer thickness regulating blade 72 is the "outer side". In addition, with regard to the "center" and "end" of the layer thickness regulating blade 72, the "center" refers to the image forming area, and the "end" refers to outside the image forming area. Hereinafter, the above meanings will be used unless otherwise specified.

[0058] The first regulating portion 74a is a regulating portion that regulates the layer thickness in a range where the image performance of the electrophotographic image forming apparatus is to be guaranteed. That is, in the first direction, the layer thickness regulation range is at least to the outside of the range where the image performance of the electrophotographic image forming apparatus is to be guaranteed, and the entire longitudinal area of ​​the first regulating portion 74a is fixed by the fixing portion W. Here, the range where the image performance is to be guaranteed refers to the longitudinal width of the image forming area required when the image forming apparatus 1 executes image formation. Therefore, the layer thickness regulation range of the first regulating portion 74a in this embodiment refers to an area slightly outside the image forming area. The layer thickness regulation range of the first regulating portion 74a is not limited to the longitudinal width, as it is only necessary to include the image forming area at least, and for example, the layer thickness regulation range of the first regulating portion 74a and the image forming area may have the same width.

[0059] 1(b), in the direction intersecting the first direction, the distance L1 from the fixed portion W to the first regulating portion 74a may be determined so as to set the pressure at which the layer thickness is to be regulated. Generally, if the pressure is low, the developer coat thickness of the developing roller 6 will be thick, and conversely, if the pressure is high, the developer layer thickness will be thin, so the pressure is determined according to the desired setting.

[0060] The second regulating portion 74e regulates the layer thickness of the developer in consideration of the sealing property so that the developer does not leak out of the developing frame 28 from the second seal member 77. Here, a phenomenon that occurs when the developer leaks out of the developing frame 28 will be described. A part of the developer that is regulated in layer thickness cannot be regulated between the first regulating portion 74a and the connecting portion 74f and the second regulating portion 74e, and the developer runs laterally along the edge ridge of the blade portion 74, which is the tip of the first regulating portion 74a. That is, a phenomenon occurs in which the developer moves in the first direction along the edge of the first regulating portion 74a of the blade portion 74. Then, the developer that runs laterally reaches the inner longitudinal end 77a of the second seal member 77, enters the second seal member 77, and is pushed into the second seal member 77 one after another, penetrating the outer longitudinal end 77b, leading to the developer leaking out. It is necessary to set the arrangement and regulating pressure of the second regulating portion 74e in consideration of this.

[0061] Therefore, the second regulating portion 74e is arranged so that the distance L2 from the fixed portion W to the second regulating portion 74e is shorter than the distance L1 from the fixed portion W to the first regulating portion 74a in the direction intersecting the first direction. As a result, the regulating pressure on the developing roller 6 at the second regulating portion 74e is higher than the regulating pressure at the first regulating portion 74a at the distance L1. That is, the layer thickness of the developer is thinner at the second regulating portion 74e than at the first regulating portion 74a. That is, the second regulating portion 74e is configured to be recessed more than the first regulating portion 74a from the end portion on the tip side of the regulating blade 72 toward the base end portion 74b. Hereinafter, the distances of the first regulating portion 74a and the second regulating portion 74e are compared, but since the recessed distance (recessed amount) from the end portion of the tip portion is changed, the recessed amount of the second regulating portion 74e having a recessed shape with respect to the tip portion of the first regulating portion 74a is quantified.

[0062] Here, the connection portion 74f is a regulating portion that smoothly connects the first regulating portion 74a and the second regulating portion 74e with a diagonal straight line shape. Since the regulating pressures of the first regulating portion 74a and the second regulating portion 74e are different, if the regulating pressure changes suddenly, the layer thickness of the developer on the developing roller 6 also changes suddenly in the longitudinal direction. Therefore, the layer thickness at the longitudinal end portion of the first regulating portion 74a that regulates the layer thickness in the range where image performance is to be guaranteed may change compared to the central portion. Therefore, the change in layer thickness may affect image formation, and it is necessary to suppress the occurrence of a sudden change in layer thickness as much as possible. Furthermore, during image formation, as the developing roller 6 rotates, the surface of the developing roller 6 and the blade portion 74 continue to rub against each other via the developer. Here, if the configuration has such that a sudden change in layer thickness occurs between the first regulating portion 74a and the second regulating portion 74e, the tip portion of the blade portion 74 may scratch the surface of the developing roller 6. Therefore, it is desirable to connect the first restricting portion 74a and the second restricting portion 74e with a smooth shape such as a diagonal line. Therefore, the first restricting portion 74a and the second restricting portion 74e may be connected in any manner as long as there is no sudden change in layer thickness between the first restricting portion 74a and the second restricting portion 74e. For example, in this embodiment, the first restricting portion 74a and the second restricting portion 74e are connected smoothly with a diagonal straight line shape, but they may be configured with a curved shape as long as the above-mentioned disadvantages are not caused.

[0063] In this embodiment, as shown in FIG. 1B, the end face of the longitudinal inner end of the second regulating portion 74e is disposed on the longitudinal outer side of the end face of the first regulating portion 74a and on the longitudinal inner side of the end face of the longitudinal outer end 77b of the second seal member 77 in the first direction. This allows the sealing pressure to be set at least on the second seal member 77 so that the developer can be sealed. Furthermore, in this embodiment, as shown in FIG. 1B, the end face of the longitudinal inner end of the second regulating portion 74e is disposed on the inner side of the end face of the longitudinal inner end 77a of the second seal member 77. This allows the required sealing pressure to be generated from the longitudinal inner end 77a of the second seal member 77, which is the path through which the developer enters the second seal member 77.

[0064] Furthermore, in this embodiment, the fixed end of the fixed part W is disposed so as to be longitudinally outer than the longitudinal inner end 77a and longitudinally inner than the longitudinal outer end 77b of the second seal member 77. The influence of the longitudinal positional relationship between the fixed end of the fixed part W and the second seal member 77 will be described below.

[0065] Fig. 7 is an explanatory diagram of the fixed part of the layer thickness regulating blade 72. Fig. 7(a) is an explanatory diagram of the fixed end of the fixed part being located longitudinally inward from the longitudinal inner end 77a of the second seal member 77, and Fig. 7(b) is an explanatory diagram of the fixed end of the fixed part W being located longitudinally outward from the longitudinal outer end 77b of the second seal member 77. Fig. 7(c) is an explanatory diagram of the state in which the longitudinal outer end 77b of the second seal member 77 is disposed longitudinally outward from the longitudinal end 74g of the blade part 74.

[0066] As shown in FIG. 7(a), when the fixed end of the fixed part W is disposed on the longitudinal inner side of the longitudinal inner end 77a, the unfixed part of the blade part 74 is deformed on the longitudinal inner side, and is less susceptible to the repulsive force of the second seal member 77. Therefore, the sealing pressure of the longitudinal inner end 77a of the second seal member 77 is weakened. In order to set a sealing pressure that prevents the developer from leaking out, the fixed distance from the fixed part W is set to the distance L3 shown in FIG. 7(a), which is shorter than the distance L2 shown in FIG. 1(b), so that a sealing pressure equivalent to the distance L2 described above can be obtained. As a result, as described above, the developer that runs horizontally along the edge ridge of the blade part 74, which is the tip of the first regulating part 74a and the second regulating part 74e, is sealed on the second seal member 77. Therefore, it is possible to prevent the developer from leaking out of the developing frame 28.

[0067] As described above, if the longitudinal inner end 77a of the second seal member 77 is separated from the longitudinal distance from the fixed end of the fixed part W, a gap may be generated between them due to deformation of the blade part 74, which may cause developer to leak out. Therefore, as shown in FIG. 1(b), it is desirable to set the end position (longitudinal end position) of the fixed part W in the first direction to be at least longitudinally outboard of the longitudinal inner end 77a of the second seal member 77 in the first direction.

[0068] Therefore, as shown in FIG. 7B, by arranging the fixed end of the fixed portion W on the longitudinal outer side of the longitudinal outer end 77b, the layer thickness regulating pressure of the second regulating portion 74e can be increased, and a sealing pressure that prevents the developer from leaking out of the entire longitudinal area of ​​the second seal member 77 can be obtained. As a result, even if the developer runs sideways along the edge ridge of the blade portion 74, which is the tip of the first regulating portion 74a and the second regulating portion 74e, it is sealed on the second seal member 77 and can be prevented from leaking out of the developing frame body 28. Therefore, the configuration of FIG. 7B is a configuration that can prevent the developer from leaking out of the longitudinal outer end 77b of the second seal member 77. However, depending on the component surface accuracy of the blade portion 74 and the attachment position accuracy and surface condition of the second seal member 77, a small amount of developer may enter from the longitudinal inner end 77a of the second seal member 77. In this case, since the sealing pressure in the second seal member 77 is high, further intrusion of the developer is suppressed and the developer may remain on the second seal member 77. Here, the invaded developer is sandwiched and rubbed between the blade portion 74, the second seal member 77, and the developing roller 6 under a high sealing pressure, and is fused to the blade portion 74 and the second seal member 77 beyond the melting point of the developer. When the developer is fused to the blade portion 74 and the second seal member 77, the fused developer may swell, causing a gap to form between the blade portion 74, the second seal member 77, and the developing roller 6 that were in close contact and sealed. Then, the developer may intrude through the gap, which may result in the developer leaking out. Therefore, as shown in FIG. 1(b), it is more preferable to set the end position (longitudinal end position) in the first direction of the fixed portion W so that it is at least longitudinally inner than the longitudinal outer end 77b in the first direction of the second seal member 77. As a result, the regulating pressure of the second regulating portion 74e does not become a high sealing pressure over the entire longitudinal area of ​​the second seal member 77, and the regulating pressure becomes weaker as it approaches the longitudinal outer end 77b. Therefore, it is possible to reduce the risk of the developer that has entered onto the second seal member 77 being fused thereto.

[0069] In addition, as shown in FIG. 7C, the longitudinal outer end 77b of the second seal member 77 is disposed longitudinally outward of the longitudinal end 74g of the blade portion 74, so that the developer that has entered the second seal member 77 only enters up to the longitudinal end 74g of the blade portion 74. Therefore, as described above, even if the developer runs laterally along the edge ridge of the blade portion 74, which is the tip of the first regulating portion 74a and the second regulating portion 74e, it is sealed on the second seal member 77. Therefore, it is possible to prevent the developer from leaking out of the developing frame 28. Furthermore, as described above, the risk of the developer fusing to the blade portion 74 and the second seal member 77 is reduced. Therefore, it is preferable that the end position (longitudinal end position) in the first direction of the fixed portion W is disposed longitudinally outward of the longitudinal inner end 77a of the second seal member 77 in the first direction and longitudinally inward of the longitudinal end 74g of the blade portion 74.

[0070] Therefore, in the configuration of this embodiment, when the layer thickness regulating blade 72 is fixed by welding, it is possible to reduce leakage of developer from the developing frame 28 while keeping the developer layer thickness of the developer coated area of ​​the developing roller 6 uniform. For this purpose, the developing cartridge 8 serving as the developing device of this embodiment is configured as follows.

[0071] The developing cartridge 8 used in the image forming apparatus 1 includes a developing frame 28 that contains a developer, a rotatable developing roller 6 that carries the developer, and a layer thickness regulating blade 72 that is fixed to the developing frame 28 and regulates the developer carried on the surface of the developing roller 6. The developing cartridge 8 further includes a second seal member 77 that seals the developer so that it does not leak out of the developing frame 28. The layer thickness regulating blade 72 includes a support plate 73 that extends in the direction of the rotation axis of the developing roller 6, and a blade portion 74 that is a plate-like member that is disposed to face the developing roller 6 at one end that is a tip end 74a, 74e in a direction intersecting with the rotation axis. The blade portion 74 is supported by the support plate 73 at the other end that is a base end 74b in a direction intersecting with the rotation axis.

[0072] The blade portion 74 is provided with regulating portions 74a and 74e that regulate the developer carried on the surface of the developing roller 6, and the regulating portions 74a and 74e are formed at one end of the blade portion 74 in contact with the developing roller 6 on the surface facing the developing roller 6. The regulating portions 74a and 74e are composed of a first regulating portion 74a and a second regulating portion 74e. The second regulating portion 74e is adjacent to the first regulating portion 74a in the rotation axis direction and is disposed farther from the center in the rotation axis direction than the first regulating portion 74a. Furthermore, the second regulating portion 74e is recessed toward the base end portion 74b of the blade portion 74 in the direction intersecting the rotation axis direction than the tip of the first regulating portion 74a.

[0073] The blade portion 74 is welded to the support plate 73 at a position where the first restricting portion 74a is formed and at a position where the second restricting portion 74e is formed in the rotation axis direction. The blade portion 74 is welded to the support plate 73 on the other end side in a direction intersecting the rotation axis direction, and is continuously welded to the support plate 73 from the position where the first restricting portion 74a is formed to the position where the second restricting portion 74e is formed in the rotation axis direction. In other words, weld marks serving as fixing portions W are continuously formed along the rotation axis direction.

[0074] Further, the following configuration may be mentioned as a preferred configuration. In a state where the blade portion 74 and the second seal member 77 are in contact with each other in a direction intersecting the rotation axis direction, the following configuration is made at the position of the blade portion 74 where the blade portion 74 and the second seal member 77 are in contact with each other in the rotation axis direction. The weld marks as the fixed portion W formed on the blade portion 74 by welding to the support plate 73 are continuously formed from the position where the first regulating portion 74a is formed in the rotation axis direction. Also, in the rotation axis direction, a welded portion where the weld marks as the fixed portion W are formed continuously from the position where the first regulating portion 74a is formed and a non-welded portion other than the fixed portion W that is not formed on the support plate 73 are formed. In addition, in the rotation axis direction, the welded portion formed on the blade portion 74 is located closer to the center of the blade portion 74 in the rotation axis direction than the non-welded portion other than the fixed portion W. By setting such a configuration, it is possible to reduce the risk of the developer that has entered onto the second seal member 77 fusing.

[0075] <Connecting part shape of layer thickness regulation blade> The detailed shape of the connection portion 74f of the layer thickness regulating blade 72 will be described with reference to Figures 1 and 8. Figure 8 is an explanatory diagram of the connection portion 74f of the layer thickness regulating blade 72. As described above, when explaining the developer layer thickness regulation of the layer thickness regulating blade 72, the shape of the connection portion 74f shown in Figure 1(b) is described in which the first regulating portion 74a and the second regulating portion 74e are connected by a diagonal straight line. However, as shown in Figures 8(a) and (b), the shape of the connection portion 74f does not necessarily have to be as shown in Figure 1(b).

[0076] 8(a), the connection portion 74f is set in a direction intersecting the first direction and perpendicular to the fixed portion W. By setting it in this manner, it is possible to reduce the size of the developer cartridge 8 in the longitudinal direction. As one example, the first regulating portion 74a and the second regulating portion 74e may be formed in a stepped shape or an arc shape so that the distance between the fixed portion W and the tip of the blade portion 74 becomes gradually shorter.

[0077] In FIG. 8(b), a third regulating portion 74h is provided between the first regulating portion 74a and the second regulating portion 74e, and the distance between the third regulating portion 74h and the fixed portion W is set to a distance L3 shorter than the distance L2. As a result, the regulating pressure of the developer layer thickness of the third regulating portion 74h becomes higher than the regulating pressure of the second regulating portion 74e that contributes to preventing leakage of the developer. Therefore, the layer thickness of the developer on the developing roller 6 becomes thinner than that of the second regulating portion 74e, and the amount of developer inserted into the second regulating portion 74e can be reduced. This makes it possible to reduce the risk of the developer fusing onto the second seal member 77. In FIG. 8(b), the distance between the fixed portion W and the tip of the third regulating portion 74h is set as the distance L3, which is the same as that in FIG. 7(a), but is not limited to the distance L3 as long as it is shorter than the distance L2. However, as described above, it should be set so that the layer thickness does not change suddenly in the longitudinal direction of the developing roller 6. EXAMPLES

[0078] In the configuration of the image forming apparatus 1 applied in this embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0079] In this embodiment, a regulating member 75 is provided as a separate member at the tip of one end of the regulating blade 72 (mainly the first regulating portion 74a in the first embodiment, and may include the second regulating portion 74e). The structure of the regulating blade 72 in this embodiment will be described with reference to Figs. 9 and 10. Fig. 9 is an exploded perspective view of the developing cartridge 8 according to this embodiment, with the mounting directions of each component indicated by arrows. Fig. 10 is a cross-sectional view of the developing cartridge 8 and drum unit 30 according to this embodiment.

[0080] The regulating blade 72 comes into contact with the developing roller 6 and regulates the thickness of the developer carried on the surface of the developing roller 6. As shown in FIG. 9, the regulating blade 72 in this embodiment is composed of a support plate 73, a blade portion 74, and a regulating member 75.

[0081] The regulating member 75 is a substantially rectangular shape extending in the first direction, and is formed inside the blade end 74g of the blade portion 74 in the first direction. The regulating member 75 is made of a rubber material such as silicone rubber or urethane rubber, or a resin material, and has flexibility. The regulating member 75 has a first surface 75a (FIG. 10) fixed to the tip portion facing the blade portion 74, and a second surface 75b which is a regulating portion that faces the developing roller 6 and contacts the surface of the developing roller 6. The corner of the tip side of the regulating blade 72 on the second surface 75b has an arc-shaped cross section as viewed from the first direction (FIG. 10). The regulating member 75 also has cutout portions 75d which are recesses at both ends in the first direction. The cutout portions 75d are recessed from the end on the tip side of the regulating blade 72 toward the base end 74b, and are recessed inward in the first direction from the ends 75c at both ends of the regulating member 75 in the first direction. The portion where the notch 75d is formed among the corners on the tip side of the regulating blade 72 of the regulating member 75 has a cross-sectional shape that is approximately right-angled when viewed from the first direction. The developing roller 6 rotates in the direction of the arrow E while rubbing against the regulating portion 75 (FIG. 10). Therefore, the portion where the notch 75d is formed among the corners on the tip side of the regulating blade 72 of the regulating portion 75 is easier to scrape off the developer on the developing roller 6 than the portion where the notch 75d is not formed on the inside in the first direction. Specifically, as shown in FIG. 10, in the portion where the notch 75d is not formed, the contact width between the developing roller 6 and the regulating portion 75 in the rotation direction of the developing roller 6 is wide. On the other hand, in the portion where the notch 75d is formed, the contact width is narrow, so that the contact pressure is high and it is easier to scrape off the developer on the developing roller 6. In addition, in the portion where the notch 75d is not formed, the tip corner of the regulating portion 75 is arc-shaped, making it easier to guide the developer toward the surface of the developing roller 6. In contrast, at the portion where the notch 75d is formed, the tip corner of the regulating portion 75 is substantially a right angle, making it difficult for the developer to be guided toward the surface of the developing roller 6 and easy to scrape off.

[0082] Both ends of the regulating portion 75 in the first direction are provided with protruding portions 75e that protrude more than other portions in a direction perpendicular to the first direction and away from the developing roller 6. The protruding portions 75e are formed to be thinner than other portions of the regulating portion 75, and are closer to the blade portion 74 than the second surface 75b. The tip of the blade portion 74 has a shape that corresponds to the regulating portion 75 and the cutout portion 75d.

[0083] The developing frame 28 accommodates the developer therein, and has a blade support surface 28a facing the support plate 73 of the regulating blade 72, and a fixing hole 28b provided in the blade support surface 28a. The developing frame 28 also has a positioning rib 28c at a position corresponding to the positioning groove 73d of the support plate 73 of the regulating blade 72, and rotatably supports the agitating gear 65 and one end of the idler gear 64. The developing frame 28 and the regulating blade 72 are fixed at both ends by fastening a fixing screw 99 through the through hole 73c to the fixing hole 28b with the blade support surface 28a butted against the support plate 73 and the positioning rib 28c engaged with the positioning groove 73d.

[0084] Next, the developer sealing structure of the developer cartridge 8 in this embodiment will be described with reference to Fig. 11. Fig. 11(a) is a diagram in which the developing roller 6 and the regulating blade 72 are not shown and the anti-scattering sheet 79 is shown by dashed lines, and Fig. 11(b) is a diagram in which the developing roller 6 and the anti-scattering sheet 79 are also shown by dashed lines. In the following description, the driven side will be used as an example, but the same applies to the non-driven side.

[0085] 11A, a first seal member 76 is provided between the regulating blade 72 and the developing frame 28 along the rotational axis direction of the developing roller 6. In addition, a second seal member 77 is provided between both ends of the regulating blade 72 in the first direction and the developing frame 28. The first seal member 76 and the second seal member 77 are members including a flexible member such as a sponge, and are compressed between the developing frame 28 and the regulating blade 72 to fill the gap between the developing frame 28 and the regulating blade 72 and suppress leakage of developer.

[0086] As shown in FIG. 11B, an end seal member 25, which is a seal member that contacts an end 75c, which is an end face of the regulating portion 75, is fixed to the blade end 74g of the blade portion 74. Here, the end 75c is the outermost part in the first direction of the second surface 75b that contacts the developing roller 6, and is the outermost part in the first direction that contacts (adheres to) an end 25a, which is an inner end face of the end seal member 25. At least a part of the end seal member 25 protrudes from the blade end 74g of the blade portion 74 toward the tip end and is fixed to the surface of the second seal member 77 facing the developing roller 6. The end seal member 25 is disposed between the blade portion 74 and the developing roller 6 in the thickness direction of the blade portion 74 that intersects with the first direction.

[0087] The end seal member 25 is a member including a flexible member such as a sponge, and is disposed between the blade portion 74 and the developing roller 6 and compressed to prevent leakage of developer from between the end seal member 25 and the regulating portion 75. In addition, at both ends of the developing roller 6 in the first direction, the second seal member 77 and the end seal member 25 are compressed to fill the gaps between the developing frame 28, the regulating blade 72, and the developing roller 6 to prevent leakage of developer.

[0088] In the configuration of this embodiment, when the layer thickness regulating blade 72 is fixed by welding, it is possible to reduce the penetration of developer into the second seal member 77 while maintaining a uniform developer layer thickness in the developer coated area on the developing roller 6. To achieve this, the developing cartridge 8, which is the developing device of this embodiment, is configured as follows.

[0089] The developer cartridge 8 used in the image forming apparatus 1 includes a developing frame 28 that contains developer, a rotatable developing roller 6 that carries the developer, and a layer thickness regulating blade 72 that is fixed to the developing frame 28 and regulates the developer carried on the surface of the developing roller 6. The developer cartridge 8 further includes a second seal member 77 that seals the developer so that it does not leak outside the developing frame 28.

[0090] The layer thickness regulating blade 72 has a support plate 73 extending in the direction of the rotation axis of the developing roller 6. Furthermore, at one end in a direction intersecting with the rotation axis direction, the blade portion 74 is disposed so as to face the developing roller 6, and at the other end in the direction intersecting with the rotation axis direction, the blade portion 74 is a plate-like member supported by the support plate 73. Furthermore, the blade portion 74 has a regulating member 75 that regulates the developer carried on the surface of the developing roller 6.

[0091] The regulating member 75 is fixed at one end to the surface of the blade portion 74 facing the developing roller 6, contacting the developing roller 6, and is formed inside the blade end of the blade portion 74 in the rotational axis direction. The regulating member 75 constitutes a regulating portion 75b that regulates the developer carried on the surface of the developing roller 6. The regulating member 75 constitutes a notch 75d as a recess that is disposed farther from the center in the rotational axis direction of the developing roller 6 than the regulating portion 75b in the rotational axis direction. The notch 75d is recessed toward the other end of the blade portion 74 than the tip of the regulating portion 75b in the direction intersecting the rotational axis direction.

[0092] The area of ​​blade portion 74 where the weld marks formed by welding to support plate 73 are formed is located on the other end side in a direction intersecting the rotational axis direction and overlaps with the center of regulating member 75 and the end where the recess is formed in the rotational axis direction.

[0093] The second seal member 77 is disposed at an end of the developing roller 6 in the direction of the rotation axis, fixed to the developing frame 28, and disposed outside the notch 75d. Furthermore, it is disposed between the developing frame 28 and the developing roller 6 in the direction intersecting the direction of the rotation axis. The end face of the blade portion 74 is located farther from the center than the end face of the second seal member 77 farther from the center in the direction of the rotation axis of the developing roller 6. When one end of the blade portion 74 and the second seal member 77 are in contact with each other, the following configuration is provided in an area overlapping the position of the blade portion 74 where the blade portion 74 and the second seal member 77 are in contact with each other in the direction of the rotation axis. The weld mark formed on the blade portion 74 by welding to the support plate 73 is formed continuously from the area of ​​the blade portion 74 overlapping the position where the regulating portion 75b is formed in the direction of the rotation axis. Furthermore, in the rotation axis direction, a welded portion where a weld mark is formed continuously from the position where the restricting portion 75b is formed is formed in the blade portion 74, and a non-welded portion where no weld mark is formed is formed in the support plate 73. The welded portion is located closer to the center in the longitudinal direction of the blade portion 74 than the non-welded portion.

[0094] Further, in the first and second embodiments, the color electrophotographic image forming apparatus has been described, but the present invention may be applied to a monochrome electrophotographic image forming apparatus.

[0095] The elements described in the above embodiments may be combined in any desired manner. [Explanation of symbols]

[0096] 1 Electrophotographic image forming apparatus (image forming apparatus) 2 Electrophotographic image forming apparatus main body (apparatus main body) 6 Developing roller 8 (8Y, 8M, 8C, 8K) Developing unit (developing cartridge) 28 Developing frame 72 Thickness-controlled blade 73 Support plate 74 Blade section 74a 1st regulation part (tip part) 74b Proximal end 74e 2nd Regulatory Division 74f Connection 74g Long end 75 Regulatory Materials 75d Notch 77 Second seal member

Claims

1. A developing device for use in an image forming apparatus, the developing device comprising: a developing frame for accommodating a developer; a developing member for carrying the developer and capable of rotating; a regulating blade for contacting the developing member so as to regulate a layer thickness of the developer on a surface of the developing member; and a sealing member for sealing an end of the developing member in a rotation axis direction to prevent the developer from leaking outside the developing frame; The regulating blade is a support plate extending in the direction of the rotation axis and fixed to the developing frame; a plate-like member extending in the rotation axis direction and supported by the support plate, the regulating blade faces the developing member at one end in a direction intersecting with the rotation axis direction, The plate-like member is welded to the support plate at the other end in the intersecting direction, and a recess is formed at the end in the rotation axis direction, which is recessed in a direction from the one end toward the other end more than a central portion, a region of the regulating blade that is welded to the support plate overlaps, in the direction of the rotation axis, the central portion of the regulating blade and the end portion where the recess is formed and the seal member is disposed, A developing device characterized in that a welding mark is formed spanning from the area of ​​the regulating blade that overlaps with the recess at the end to the area of ​​the regulating blade that overlaps with the position where the sealing member is disposed in the direction of the rotation axis.

2. A developing device as described in Claim 1, characterized in that the sealing member is positioned outside and away from the central portion than a notch extending in the direction of the rotational axis forming the recess, and the notch and the sealing member are positioned adjacent to each other in the direction of the rotational axis.

3. A developing device as described in Claim 2, characterized in that the position of the end of the weld mark in the direction of the rotation axis formed in the area of ​​the regulating blade that overlaps with the position where the sealing member is arranged is closer to the central portion than the position of the second end, which is the end of the sealing member opposite to the first end, which is the end of the sealing member on the side where the cutout portion and the sealing member are arranged adjacent to each other in the direction of the rotation axis.

4. Further comprising a fixing screw for fixing the support plate to the developing frame body, the fixing screw is inserted into a through hole formed in the support plate and fixed to a fixing hole formed in the developing frame, thereby fixing the support plate to the developing frame; 2. The developing device according to claim 1, wherein the position of the end of the weld mark in the direction of the rotation axis formed in the region of the regulating blade that overlaps with the position where the seal member is disposed is closer to the central portion than the center position of the fixing screw.

5. A developing device as described in Claim 4, characterized in that the fixing screw is a Phillips screw.

6. 2. The developing device according to claim 1, wherein the developer contained in the developing frame is yellow.

7. 2. The developing device according to claim 1, wherein the developer contained in the developing frame is magenta.

8. 2. The developing device according to claim 1, wherein the developer contained in the developing frame is cyan.

Images