Restriction member, developing device, process cartridge, and image forming apparatus

Abstract

A restricting member, a developing device, a process cartridge, and an image forming apparatus are disclosed. A restricting member includes a blade portion and a support portion. A contact portion is provided at the blade portion, and in a cross section orthogonal to a longitudinal direction, the contact portion includes a first portion extending in a first direction and a second portion extending from an end of the first portion toward a free end and in a second direction. When an area divided by connecting an intersection point, an end of the first portion, and an end of the second portion with straight lines is defined as a first area, an area of the first area on a longitudinal end portion of the blade portion is smaller than an area of the first area on a longitudinal central portion, the intersection point being where an imaginary line intersects an extension line of the first portion in the first direction.

Description

TECHNICAL FIELD

[0001] The present application relates to an image forming apparatus and a restriction member, a developing device, or a process cartridge each used in the image forming apparatus. In particular, the present application relates to an electrophotographic image forming apparatus using an electrophotographic method and a restriction member, a developing device, or a process cartridge each used in the electrophotographic image forming apparatus. BACKGROUND

[0002] Hitherto, in an image forming apparatus, a toner carried by a developing roller makes the thickness of a toner layer be limited by a developing blade.

[0003] Japanese Patent Publication No. 9-329961 (Patent Literature 1 (PTL 1)) proposes a structure for preventing the thickness of a toner layer from becoming excessively large at a developing blade that limits the thickness of the toner layer. Specifically, PTL 1 discloses a structure in which a "cutout" is formed in a free end of the developing blade that contacts the developing roller, so that the free end continuously becomes shorter from the center side toward the end portion side in a longitudinal direction of the developing blade.

[0004] However, the structure in PTL 1 has the following problem. That is, in order to form the "cutout" in the free end of the developing blade, both end portions of the developing blade need to be cut. Since a cutting piece to be discarded is generated when the developing blade is cut, the use efficiency of raw materials can be reduced. SUMMARY

[0005] In view of the above problem, the present application provides a structure designed to increase uniformity in a longitudinal direction of a developer layer carried by a developer carrying member while improving the use efficiency of raw materials at the time of manufacture.

[0006] The developing device according to the present application is one including:

[0007] a developer carrying member configured to carry a developer; and

[0008] a restriction member configured to limit the thickness of a layer of the developer on the developer carrying member,

[0009] wherein the restriction member includes:

[0010] a blade portion extending in a longitudinal direction, and

[0011] a support portion supporting a first end portion of the blade portion in a lateral direction orthogonal to the longitudinal direction,

[0012] wherein a contact portion for contacting a surface of the developer bearing member is provided at a second end portion of the blade portion in the lateral direction opposite to the first end portion in the lateral direction, the second end portion including a free end,

[0013] wherein, in a cross section orthogonal to the longitudinal direction, the contact portion includes:

[0014] a first portion extending in a first direction along the lateral direction and contacting the developer bearing member, and

[0015] a second portion extending in a second direction intersecting the first direction from an end of the first portion on a side of the free end toward the free end such that the second portion gets farther from the surface of the developer bearing member as it progresses toward the free end, and

[0016] wherein, when an area divided by connecting the end of the second portion on a side of the free end, the end of the first portion, and an intersection point in the second direction with a straight line is defined as a first area,

[0017] in the longitudinal direction of the blade portion, an area of the first area on a longitudinal end portion of the blade portion is smaller than an area of the first area on a longitudinal central portion of the blade portion, the intersection point being where an imaginary line orthogonal to the first direction and passing the end of the second portion intersects an extension line of the first portion in the first direction.

[0018] Other features of the present application will become apparent from the following description of example embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1A is a conceptual diagram illustrating a lateral direction scraping amount in a longitudinal direction of a developing blade according to an embodiment of the present application. FIG. 1B is FIG. 1A is an enlarged conceptual diagram of an end portion side shown in FIG. 1C is a conceptual diagram illustrating a thickness direction scraping amount in a longitudinal direction of a developing blade. FIG. 1D is FIG. 1C is an enlarged conceptual diagram of an end portion side shown in

[0020] FIG. 2A is a cross-sectional conceptual diagram of a developing blade according to an embodiment of the present application in a lateral direction. FIG. 2B is a perspective conceptual diagram of a developing blade according to an embodiment of the present application in a longitudinal direction.

[0021] FIG. 3A to FIG. 3D Each illustrates a method of polishing a developing blade according to an embodiment of the present application.

[0022] FIG. 4 A dimensional relationship in a longitudinal direction between members constituting a developing unit according to an embodiment of the present application is shown.

[0023] FIG. 5A A contact state at a central side between a developing roller and a developing blade in a developing unit according to an embodiment of the present application is illustrated. FIG. 5B A contact state at an end side between a developing roller and a developing blade in a developing unit according to an embodiment of the present application is illustrated.

[0024] FIG. 6 is a vertical sectional conceptual view of a process cartridge according to an embodiment of the present application.

[0025] FIG. 7 is a vertical sectional conceptual view of an image forming apparatus according to an embodiment of the present application.

[0026] FIG. 8A is a cross-sectional view in a lateral direction of a developing unit according to a comparative example of the present application. FIG. 8B is a perspective view in a longitudinal direction of a developing unit according to a comparative example of the present application.

[0027] FIG. 9A A lateral direction shaving amount in a longitudinal direction of a developing blade according to a comparative example of the present application is illustrated. FIG. 9B is FIG. 9A is an enlarged conceptual view of an end side shown in FIG. 9C A thickness direction shaving amount in a longitudinal direction of a developing blade is illustrated. FIG. 9D is FIG. 9C is an enlarged conceptual view of an end side shown in DETAILED DESCRIPTION

[0028] Hereinafter, exemplary embodiments of the present application will be described with reference to the accompanying drawings.

[0029] Note that, for example, the size, material, shape, and relative arrangement of structural components described in the following embodiments are examples and do not limit the scope of the present application.

[0030] Structure of Image Forming Apparatus

[0031] Next, with reference to FIG. 7 An image forming apparatus 100 according to an embodiment will be described.

[0032] FIG. 7 is a vertical sectional conceptual view of an image forming apparatus according to an embodiment of the present application.

[0033] Specifically,FIG. 7 A cross section of an image forming apparatus 100 including a process cartridge according to the present embodiment is shown.

[0034] The image forming apparatus 100 of the present embodiment is a full-color laser beam printer using a tandem method or an intermediate transfer method. The image forming apparatus 100 is capable of forming a full-color image on a transfer material such as a recording sheet, a plastic sheet, or cloth according to image information. The image information is input to the main body of the image forming apparatus or to an image reading device connected to the main body of the image forming apparatus from a host device of a personal computer connected to the main body of the image forming apparatus so as to be capable of communicating therewith, for example.

[0035] The image forming apparatus 100 includes process cartridges 7 each constituting a corresponding one of a plurality of image forming devices (SY, SM, SC, SK). The image forming devices are each provided for a corresponding one of yellow (Y), magenta (M), cyan (C), and black (K), and can each form an image of a corresponding one of the colors (Y, M, C, K). In the present embodiment, the image forming devices (SY, SM, SC, SK) are disposed in a row in a direction intersecting the vertical direction.

[0036] Note that the process cartridges 7 are each attached to and detached from the image forming apparatus 100 via mounting devices such as mounting guides or positioning members provided at the main body of the image forming apparatus. In the present embodiment, the color process cartridges 7 all have the same shape, and each of yellow (Y) toner, magenta (M) toner, cyan (C) toner, and black (K) toner is stored inside a corresponding one of the color process cartridges 7. Although in the present embodiment the process cartridges are described as being attached and detached, the developing units (developing devices) can be configured to be attached to and detached from the main body of the image forming apparatus.

[0037] The photosensitive drums 1 are each rotationally driven by a not-shown driving device (driving source). A scanner unit (exposure device) 30 is disposed near the photosensitive drums 1. The scanner unit 30 is an exposure unit that irradiates the photosensitive drums 1 with laser light and forms an electrostatic latent image on the photosensitive drums 1 based on image information.

[0038] The surface potential (bright potential) of each photosensitive drum 1 is set to become -100 V after exposure in the present embodiment. An intermediate transfer belt 31 serving as an intermediate transfer body for transferring a toner image on the photosensitive drums 1 to a transfer material P (recording material) is disposed opposite the four photosensitive drums 1.

[0039] The annular intermediate transfer belt 31 serving as an intermediate transfer body contacts all of the photosensitive drums 1 and moves by circulating (rotating) in the direction of the arrow B shown (counterclockwise direction).

[0040] Four primary transfer rollers 32 serving as primary transfer devices are disposed in parallel on the inner circumferential surface side of the intermediate transfer belt 31 so as to oppose corresponding ones of the photosensitive drums 1. A bias having a polarity opposite to that of the normal charge of the toner is applied to the primary transfer rollers 32 from a primary transfer bias power source (high voltage power source) serving as a primary transfer bias application device (not shown). Thus, the toner images on the photosensitive drums 1 are transferred (primary transfer) to the intermediate transfer belt 31.

[0041] A secondary transfer roller 33 serving as a secondary transfer device is disposed on the outer circumferential surface side of the intermediate transfer belt 31. A bias having a polarity opposite to that of the normal charge of the toner is applied to the secondary transfer roller 33 from a secondary transfer bias power source (high voltage power source) serving as a secondary transfer bias application device (not shown). Thus, the toner images on the intermediate transfer belt 31 are transferred (secondary transfer) to the transfer material P.

[0042] For example, when a full-color image is formed, the above-described processes are continuously performed at the image forming units SY, SM, SC, and SK, and the toner images of the respective colors are continuously superimposed on each other on the intermediate transfer belt 31 and transferred thereonto. Then, in synchronization with the movement of the intermediate transfer belt 31, the transfer material P is conveyed to the secondary transfer portion. Due to the action of the secondary transfer roller 33 contacting the intermediate transfer belt 31 via the transfer material P, the four-color toner images on the intermediate transfer belt 31 are collectively secondary-transferred to the transfer material P.

[0043] The transfer material P on which the toner images are transferred is conveyed to a fixing device 34 serving as a fixing unit. By applying heat and pressure to the transfer material P at the fixing device 34, the toner images are fixed to the transfer material P.

[0044] Structure of the process cartridge

[0045] The overall structure of the process cartridge 7 mounted on the image forming apparatus according to the embodiment is described.

[0046] FIG. 6 is a vertical sectional conceptual view of the process cartridge according to the embodiment of the present application.

[0047] Specifically, FIG. 6 A main section of the process cartridge 7 of the present embodiment when viewed in the longitudinal direction (rotation axis direction) of the photosensitive drums 1 is shown. Note that in the present embodiment, the structures and operations of the process cartridges 7 for the respective colors are basically the same except that the types (colors) of the developers they store are different.

[0048] The process cartridge 7 includes a photosensitive unit 12 including, for example, the photosensitive drums 1, and a developing unit 3 (developing device) including, for example, the developing rollers 4 (developer bearing members).

[0049] The photosensitive drum 1 is rotatably attached to the photosensitive unit 12 via a bearing (not shown). The photosensitive drum 1 is subjected to a driving force of a driving motor serving as a driving device (driving source) that is not shown, and is thus rotationally driven at a speed of 300 mm / sec in the direction of the arrow A illustrated in accordance with an image forming operation.

[0050] A charging member (charging roller) 2 for charging the photosensitive drum 1 and a cleaning member 6 are disposed at the photosensitive unit 12 to contact an outer peripheral surface of the photosensitive drum 1.

[0051] The charging member 2 is configured to rotate by rotation of the photosensitive drum 1, and can be applied with a voltage by a voltage application device (not shown).

[0052] The charging roller 2 is formed by continuously stacking an electrically conductive elastic layer and a high resistance layer on a metal core having a length of 232 mm in the longitudinal direction. Specifically, an electrically conductive elastic layer made of polyurethane rubber having a thickness of approximately 3 mm is formed around a metal core having a length of 240 mm in the longitudinal direction and a diameter of 6 mm. Then, a high resistance layer in which carbon black is dispersed in polyurethane rubber having a thickness of several μm is formed on the elastic layer.

[0053] Both end portions of the metal core of the charging roller 2 are rotatably supported by electrically conductive support members, and in addition, the support members are urged by spring members so as to move in the direction of the photosensitive drum 1.

[0054] Therefore, the charging roller 2 is in pressure contact with the photosensitive drum 1 by a predetermined pressure against the elasticity of the electrically conductive elastic layer, so that a charging nip is formed. The charging roller 2 contacts the photosensitive drum 1 and is rotated by rotation of the photosensitive drum 1.

[0055] Then, a direct current voltage is applied to the charging roller 2 by a power source via the metal core, and the surface of the photosensitive drum 1 is uniformly charged. In the present embodiment, a charging bias is applied so that the surface potential of the photosensitive drum 1 becomes -500 V during image formation.

[0056] The cleaning blade 6 has a structure in which a SUS metal plate and a rubber tip that is elastic at the end portion (free end) of the metal plate are in pressure contact with each other, with a length of 250 mm in the longitudinal direction. The end portion of the rubber tip of the cleaning blade 6 contacts the photosensitive drum 1 at a desired angle and a desired amount of intrusion (distance).

[0057] In order to ensure good cleaning performance, the contact pressure of the cleaning blade 6 with respect to the surface of the photosensitive drum 1 is approximately 80 g / cm. Residual toner on the surface of the photosensitive drum 1 is removed by this cleaning blade structure.

[0058] A developing roller 4 serving as a developer carrying member is disposed at the developing unit 3 in contact with the photosensitive drum 1 and rotates in the direction of the illustrated arrow D (counterclockwise direction). The developing roller 4 is an electro-conductive elastomer formed of a low-hardness rubber material such as silicone or polyurethane, or a low-hardness rubber material foam, or a combination thereof. The low-hardness rubber material and the foam have an electro-conductive agent such as carbon dispersed therein, and have a volume resistivity of 10 2 Ωcm to 10 10 Ωcm. The elastomer has an outer diameter of 20 mm and a length of 235 mm in the longitudinal direction. The developing roller 4 contacts the photosensitive drum 1 with a desired contact pressure.

[0059] In the present embodiment, the developing roller 4 and the photosensitive drum 1 rotate so that their surfaces move in the same direction (in the present embodiment, from the bottom toward the top) at the opposing portions (contact portions). During formation of an image, a voltage (hereinafter referred to as a developing bias) is applied to the developing roller 4 by a voltage application device (not shown). In the present embodiment, the developing bias during formation of an image is such that a direct current voltage of -350 V is applied.

[0060] A developer supply roller 5 (hereinafter simply referred to as a "supply roller") serving as a device for supplying and collecting a developer is disposed at the developing unit 3 so as to rotate in the direction of the illustrated arrow E (counterclockwise direction). Here, the supply roller 5 contacts the outer peripheral surface of the developing roller 4. The supply roller 5 is an elastic roller formed of, for example, an elastomer, and in the present embodiment, an insulating sponge roller having an outer diameter of 16 mm and a length of 220 mm in the longitudinal direction is disposed at the place where it contacts the developing roller 4. The supply roller 5 and the developing roller 4 rotate so that their surfaces move in opposite directions at the opposing portions (contact portions).

[0061] A developing blade 8 (limiting member) that contacts the outer peripheral surface of the developing roller 4 and scrapes, makes uniform, and limits the thickness of the toner layer is disposed at the developing unit 3. The developing blade 8 includes thin plates 81 (blade portions) and a support plate 82 (support portion) that each extend in the following longitudinal direction Al. One end 81a (fixed end) of the thin plate 81 in the transverse direction A2 orthogonal to the longitudinal direction is fixed to the support plate 82, and the other end 81b is a free end and includes a contact portion 810 (described below).

[0062] The thin plate 81 is formed of SUS (stainless steel) processed into the form of a spring leaf, and has a thickness of 80 μm and a length of 230 mm in the longitudinal direction. The contact portion 810 disposed at the free end (other end 81b) of the thin plate 81 contacts the developing roller 4 with a desired contact pressure.

[0063] The layer thickness of the toner supplied to the developing roller 4 is limited by the developing blade 8, and a thin toner layer to which an electric charge is applied by triboelectric charging is formed on the developing roller 4. As the developing roller 4 rotates, the toner is supplied to the developing area.

[0064] The toner that is still carried by the developing roller 4 without contributing to the developing operation is removed from the developing roller 4 due to the friction of the supply roller 5. The removed part of the toner is again supplied to the developing roller 4 by the supply roller 5 together with new toner supplied to the supply roller 5, and the remaining toner returns to the toner storage chamber 13 and is collected inside thereof. In this way, in the present embodiment, the supply roller 5 has two functions, i.e., a function of supplying toner and a function of collecting toner.

[0065] The toner storage chamber 13 serving as a developer storage chamber stores a developer (toner) having a particle diameter of 7 μm. Inside the toner storage chamber 13, a toner conveying member 11 rotatably supported is provided. Note that, in the present embodiment, the developer is a non-magnetic single-component developer.

[0066] The toner conveying member 11 stirs the toner stored inside the toner storage chamber 13 and conveys the toner toward a developing chamber 14 in which the developing roller 4 and the supply roller 5 are provided. The developing chamber 14 has a developing opening having a length of 226 mm in a longitudinal direction as an opening portion for conveying the toner outside the developing unit 3. The developing roller 4 is assembled to the developing unit 3 in an arrangement that closes the developing opening.

[0067] Note that, the present embodiment is applicable to a structure serving as a developer container (toner cartridge) having only the toner storage chamber 13 and the toner conveying member 11 and attached to and detached from a main body of an apparatus.

[0068] Structure of limiting member

[0069] Next, the developing blade 8 (limiting member) according to the embodiment will be described in detail.

[0070] FIG. 2A is a sectional conceptual view of the developing blade according to the embodiment of the present application in a lateral direction. FIG. 2B is a perspective conceptual view of the developing blade in a longitudinal direction.

[0071] In the present embodiment, as shown in FIG. 2A , the developing blade 8 includes a support plate 82 formed of machined stainless steel and a thin plate 81 (blade portion) machined into the form of a spring leaf.

[0072] The thin plate 81 is integrated with the support plate 82 (support portion) by YAG laser welding.

[0073] As shown in FIG. 2BAs shown in FIG. 6, in the present embodiment, by the polishing operation, a portion of the "end edge portion" (not shown) on the side to be contacted with the developing roller is scraped off from the end (free end) side of the thin plate 81 of the developing blade 8. The portion (second portion) formed by the scraping is formed in the entire region in the longitudinal direction Al. As shown in FIG. 6, the polishing operation is such that the scraping amount (distance) in the lateral direction A2 with respect to the end edge portion is Ps and the scraping amount in the thickness direction A3 is Pt. FIG. 2A

[0074] Specifically, in the present embodiment, the developing blade 8 includes the thin plate 81 extending in the longitudinal direction Al and the support plate 82 supporting one end 81a of the thin plate 81 in the lateral direction A2 orthogonal to the longitudinal direction.

[0075] The developing blade 8 includes a contact portion 810 provided at the other end 81b (the other end portion) of the thin plate 81 as the free end in the lateral direction A2 and arranged to contact the surface of the developing roller 4.

[0076] More specifically, in the present embodiment, in the cross section orthogonal to the longitudinal direction Al, the contact portion 810 has a first portion 811 (first surface) provided on the side of the contact portion 810 contacting the developing roller 4 and a third portion 813 (third surface) orthogonal to the first portion 811. Before the polishing operation, the first portion (first surface) and the third portion (third surface) intersect each other and form the above-mentioned "end edge portion". By the polishing operation, a second portion 812 (second surface) connecting the first portion and the third portion is formed.

[0077] That is, in the cross section orthogonal to the longitudinal direction Al, the contact portion 810 has the first portion 811 and the second portion 812.

[0078] Note that the first portion 811 extends in a first direction A21 along the lateral direction A2 and contacts the developing roller 4.

[0079] On the other hand, the second portion 812 extends further toward the free end from the end D1 of the first portion 811 and extends in a second direction A22 intersecting the first direction A21.

[0080] An imaginary line Bl passing through the end D2 of the second portion 812 orthogonal to the first direction A21 intersects an extension line B2 of the first portion 811 in the first direction A21 (intersection point D3). The region divided by connecting the intersection point D3, the end D1 of the first portion 811, and the end D2 of the second portion 812 by straight lines (three imaginary lines) can be defined as a "take-in region (first region)".

[0081] ​In the present embodiment, in the longitudinal direction Al, the area of the receiving region S2 of the end portion side ES of the sheet 81 is smaller than the area of the receiving region Sl of the central side CS located on the inner side of the end portion side.

[0082] Next, a method of polishing the sheet 81 is described using FIG. 3.

[0083] FIG. 3A to FIG. 3D Each illustrates a method of polishing a developing blade according to an embodiment of the present application.

[0084] As FIG. 3A shown in FIG. 2, the sheet 81 is fixed to the base 94 by being interposed between the base 94 and the holding member 93 before being joined to the support plate 82. The polishing film 92 wound around the rubber roller 91 contacts the end portion of the sheet 81 when the polishing film 92 is subjected to a load. In the present embodiment, a wound film sheet of granularity #800 is used for the polishing film 92, and a load of 500 g is applied to the rubber roller 91.

[0085] The polishing film 92 on the rubber roller 91 is disposed in a fixed state. As FIG. 3B , FIG. 3C and FIG. 3D shown in FIG. 3, the end portion of the sheet 81 is rubbed against and finely shaved by the polishing film 92 due to the movement of the base 94 to the left and right in the longitudinal direction F and the direction G. Since the sheet 81 is microfabricated by polishing, the occurrence of a cut piece is very slight when a shape is formed.

[0086] The shaving amount of the sheet 81 is proportional to the rubbing distance with respect to the polishing film 92. The greater the rubbing distance, the greater the shaving amount, and the smaller the rubbing distance, the smaller the shaving amount. That is, by controlling the movement amount of the base 94, the rubbing amount between the sheet 81 and the polishing film 92 can be changed longitudinally, and thus the shaving amount can be controlled. As in the present embodiment, when the shaving amount of both end portions of the sheet 81 is to be reduced, the rubbing distance of the both end portions with respect to the polishing film 92 is made smaller than the rubbing distance of other portions with respect to the polishing film 92.

[0087] Next, the relationship of the longitudinal arrangement of each member is described using FIG. 4 FIG. 4.

[0088] FIG. 4 The dimensional relationship in the longitudinal direction between the members constituting the developing unit according to an embodiment of the present application is shown.

[0089] The length LI (220 mm) of the supply roller 5 in the longitudinal direction contacts the surface of the developing roller 4 in the range of the central side CS (region CS1) of the length L4 (235 mm) of the developing roller 4 in the longitudinal direction, and the developing blade 8 is disposed to contact the surface of the developing roller 4 in the range of the length L3 (230 mm) in the longitudinal direction. The developing chamber frame 15 filled with toner has an opening (developing opening) of a length L5 (226 mm) (opening width) in the longitudinal direction, and the developing roller 4 is disposed to face the developing opening. Thus, the developing roller 4 can carry toner of a length in the longitudinal direction corresponding to the developing opening width (L5).

[0090] To prevent the supply roller 5 from being deformed or damaged due to rotation of the end portion of the supply roller 5 while the supply roller 5 is in contact with the inner wall of the developing opening, a gap of 3 mm in the longitudinal direction is provided on each side between the supply roller 5 and the developing chamber frame.

[0091] Although the toner coated on the developing roller 4 is transferred to the developing area to perform the developing operation, the toner not used for the developing operation is removed by the supply roller 5, and a part of the removed toner is again supplied to the developing roller 4 by the supply roller 5 together with new toner inside the developing chamber 14.

[0092] Since the supply roller 5 does not contact the developing roller 4 in each region having a longitudinal width L2 (at the end portion side ES), the supply roller 5 does not perform the removal operation in these regions. Thus, the toner coating portion of the developing roller 4 at each L2 position is such that the toner coating gradually accumulates, and thus, the toner coating at each portion having a longitudinal width L2 becomes thick. Thus, the toner coating portion of each portion having a longitudinal width L2 is no longer possible to have a normal charge, resulting in occurrence of toner scattering or toner dripping.

[0093] The above problem can be mitigated by changing the cross-sectional area of the shape of the toner receiving region (S1, S2) formed by the thin plate 81 and the developing roller 4 at the longitudinal contact position LI portion (region of the central side CS) of the supply roller 5 and at each longitudinal non-contact position L2 portion (region of the end portion side ES) of the supply roller 5.

[0094] Next, the amount of shaving of the developing blade is described in detail with reference to FIG. 1A to FIG. 1D The amount of shaving of the developing blade is described in detail with reference to

[0095] FIG. 1A is a conceptual view illustrating the amount of shaving in the lateral direction of the longitudinal direction of the developing blade according to an embodiment of the present application.

[0096] FIG. 1B is a conceptual view illustrating the amount of shaving in the lateral direction of the longitudinal direction of the developing blade according to an embodiment of the present application. FIG. 1A is an enlarged conceptual view of the end portion side shown in

[0097] FIG. 1C is a conceptual diagram illustrating a thickness direction shaving amount in a longitudinal direction of a developing blade.

[0098] FIG. 1D is FIG. 1C is an enlarged conceptual diagram of an end portion side illustrated in

[0099] That is, FIG. 1A to FIG. 1D is a graph of a longitudinal shaving amount of a contact surface portion of a thin plate 81 of a developing blade 8 of a contact developing roller 4 according to the present embodiment.

[0100] More specifically, FIG. 1A shows a lateral direction shaving amount Ps of the thin plate 81, and FIG. 1B shows a lateral direction shaving amount Ps of a portion (i.e., one end portion in FIG. 1A ) extending from 0 mm to 25 mm in the longitudinal direction.

[0101] FIG. 1C shows a thickness direction shaving amount Pt of the thin plate 81. FIG. 1D shows a thickness direction shaving amount Pt of a portion (i.e., one end portion in FIG. 1C ) extending from 0 mm to 25 mm in the longitudinal direction. Note that a laser microscope VK-X200 (manufactured by Keyence Corporation) was used to measure the shaving amounts.

[0102] In the present embodiment, as FIG. 1B and FIG. 1D shown in , the shaving amounts Ps1 and Pt1 of a portion (a region of the central side CS1) in which the supply roller 5 contacts the longitudinal contact position L1 of the developing roller 4 are different from the shaving amounts Ps2 and Pt2 of a portion (a region of the end portion side ES) in which the supply roller 5 does not contact the longitudinal non-contact position L2 of the developing roller 4.

[0103] Specifically, Ps2 (15 μm < Ps2 < 40 μm) is smaller than Ps1 (approximately 40 μm), and Pt2 (3 μm < Pt2 < 15 μm) is smaller than Pt1 (15 μm).

[0104] In other words, when the polishing operation is performed, the shaving amount in the lateral direction A2 is Ps1 and the shaving amount in the thickness direction A3 of the thin plate 81 is Pt1 at the central side CS. The shaving amount in the lateral direction A2 is Ps2 at the end portion side ES. The shaving amount of the thin plate 81 in the thickness direction A3 is Pt2. Here, the contact portion 810 of the thin plate 81 is configured to satisfy the relationship Ps1 > Ps2 and the relationship Pt1 > Pt2.

[0105] This structure provides the following effects.

[0106] FIG. 5AThe contact state between the central side of the developing roller and the developing blade in the developing unit according to the embodiment of the present application is illustrated. FIG. 5B The contact state of the end side between the developing roller and the developing blade is illustrated.

[0107] Specifically, FIG. 5A A vertical cross section showing that the supply roller 5 in the longitudinal direction contacts the contact portion of the developing blade 8 at the LI portion of the developing roller 4 is shown. FIG. 5B A vertical cross section showing that the supply roller 5 in the longitudinal direction does not contact the contact portion of the developing blade 8 at the L2 portion of the developing roller 4 is shown. Note that, FIG. 5A The receiving area SI (hatched portion) shown in (a) and FIG. 5B The receiving area S2 (hatched portion) shown in (b) are each an area interposed between the developing roller 4 and the developing blade 8 and provided for receiving toner flowing in the moving direction of the surface of the developing roller. The cross-sectional area of the receiving area (shape) in the present embodiment is calculated by using the lateral direction shaving amount Ps and the thickness direction shaving amount Pt.

[0108] In particular, as FIG. 1B shown in (a), at the end side ES, the shaving amount Ps2 in the lateral direction A2 decreases toward the outside in the longitudinal direction Al. As FIG. 1D shown in (b), at the end side ES, the shaving amount Pt2 in the thickness direction A3 decreases toward the outside in the longitudinal direction Al.

[0109] In the present embodiment, the cross-sectional area of the receiving area SI (shape) at the contact position of the supply roller 5 in Fig. 5 is approximately 300 μm 2 , and the cross-sectional area of the receiving area S2 (shape) at the non-contact position of the supply roller 5 is approximately 50 μm 2 .

[0110] In other words, in the present embodiment, in the longitudinal direction Al, the end side ES is located outside the end CS11 of the region CS1 of the supply roller 5 that contacts the developing roller 4. In the longitudinal direction Al, the central side CS is located inside the end CS11 of the region CS1 of the supply roller 5 that contacts the developing roller 4.

[0111] By making the area of the receiving area SI corresponding to the central side larger than the area of the receiving area S2 corresponding to the end side, toner normally supplied by the supply roller 5 is stably supplied to the receiving area of the developing blade 8. Toners not used in the developing operation are removed by the supply roller 5.

[0112] On the other hand, by making the sectional area of the toner-receiving region S2 (shape) of the portion L2 where the supply roller 5 does not contact the developing roller 4 in the longitudinal direction small, the restriction force can be increased. Thus, although the toner tends to accumulate due to the supply roller 5 not performing the removal operation at the portion L2 where the supply roller 5 does not contact the developing roller 4, the increase in the thickness of the toner coating can be suppressed by the restriction force of the developing blade 8 due to the receiving region (shape) of the developing blade 8 being small.

[0113] Evaluation Test

[0114] With the developing unit 3 and the image forming apparatus 100 according to the present embodiment, the uniformity in the longitudinal direction of the toner coating on the developing roller 4 was examined. The evaluation condition was to continuously print an image on up to 10,000 sheets of A4 size at a print ratio of 2%, and the evaluation environment was 25°C / 50% RH.

[0115] Next, the embodiment of the present application was compared with FIG. 8A and FIG. 8B and FIG. 9A to FIG. 9D as shown in Comparative Example 1.

[0116] FIG. 8A is a cross-sectional view in the lateral direction of the developing unit according to the comparative example of the present application. FIG. 8B is a perspective view in the longitudinal direction of the developing unit according to the comparative example.

[0117] FIG. 9A illustrates the lateral direction shaving amount in the longitudinal direction of the developing blade according to the comparative example of the present application. FIG. 9B is an enlarged conceptual view of the end portion side as shown in FIG. 9A .

[0118] FIG. 9C illustrates the thickness direction shaving amount in the longitudinal direction of the developing blade according to the comparative example. FIG. 9D is an enlarged conceptual view of the end portion side as shown in FIG. 9C .

[0119] In the comparative example of the present embodiment, as shown in FIG. 9A to FIG. 9D , the longitudinal shaving amount of the thin plate 81 of the developing blade 8 was uniform.

[0120] Specifically, FIG. 9A shows the lateral direction shaving amount Ps in the entire longitudinal region of the thin plate 81. FIG. 9B shows the lateral direction shaving amount Ps of the portion (i.e., one end portion in FIG. 9A ) extending from 0 mm to 25 mm in the longitudinal direction. FIG. 9C shows the thickness direction shaving amount Pt in the thickness direction of the thin plate 81. FIG. 9DA portion extending from 0 mm to 25 mm in the longitudinal direction (i.e., one end portion) in the thickness direction is shown as a thickness direction shaving amount Pt. FIG. 9C

[0121] As a result, even after the evaluation ended, the developing unit 3 according to the embodiment including the developing blade 8 using the thin plate 81 had a uniform toner coating on the developing roller in the longitudinal direction, and toner scattering or toner dripping did not occur. This is because the cross-sectional area of the receiving region S2 (shape) of the developing blade 8 at the L2 portion located at the non-contact position of the supply roller 5 was small, resulting in an increase in the restriction force.

[0122] On the other hand, in the developing unit 3 according to the comparative example including the developing blade 8 using the thin plate 81, toner scattering or toner dripping occurred when printing was performed on 6000 sheets. This is because the supply roller 5 did not perform a removal operation on the L2 portion located at the non-contact position of the supply roller 5 from the developing roller 4, and because the restriction force of the developing blade 8 was weak, as a result, the toner coating became thick and the toner could not have a normal charge.

[0123] Although in the present embodiment, the thin plate 81 is formed of SUS as stainless steel, the thin plate 81 can be a phosphor bronze plate having the same shape or a thin plate on which a resin covering member such as a polyamide elastomer covering member is laminated, as long as the contact portion thereof that contacts the developing roller 4 can be microprocessed.

[0124] If the shaving amounts of the contact portion (Ps1, Pt1) of the thin plate 81 that contacts the supply roller 5 and the non-contact portion (Ps2, Pt2) of the thin plate 81 that does not contact the supply roller 5 have the relationships Ps1>Ps2and Pt1>Ps2, the effects can be provided. As absolute values of the shaving amounts, the shaving amounts of the thin plate 81 are appropriately adjusted so that the shaving amounts become toner coating amounts on the developing roller 4 required by the system.

[0125] As described above, at the thin plate 81 of the developing blade 8, the shaving amount of the thin plate 81 at the non-contact position of the supply roller 5 can be made smaller than the shaving amount of the thin plate 81 at the longitudinal position where the supply roller 5 contacts. Therefore, an increase in the thickness of the toner coating at the non-contact position of the supply roller 5 can be suppressed. In addition, by polishing to form a fine shaving shape, the amount of cut pieces at the time of processing during manufacturing can be reduced.

[0126] ​According to the present application, therefore, the cross-sectional area of the receiving region (shape) of the developing blade 8 at the non-contact position of the supply roller 5, at which the supply roller 5 does not contact the developing roller, can be made smaller than the cross-sectional area of the receiving region (shape) of the developing blade at the contact position of the supply roller, at which the supply roller contacts the developing roller. As a result, the toner on the developing roller can be made uniform in the longitudinal direction, and thus the occurrence of toner scattering or toner dripping can be suppressed. Since the microprocessing is performed by the polishing operation, the amount of material to be discarded at the time of manufacture can be minimized.

[0127] The present application can be summarized as follows.

[0128] (1) A developing device 3 according to the present application includes:

[0129] a developer carrying member 4 configured to carry a developer; and

[0130] a restricting member 8 configured to restrict the thickness of a layer of the developer on the developer carrying member.

[0131] The restricting member includes:

[0132] a blade portion 81 extending in a longitudinal direction Al; and

[0133] a support portion 82 supporting a first end portion of the blade portion in a lateral direction A2 orthogonal to the longitudinal direction.

[0134] a contact portion 810 for contacting a surface of the developer carrying member is provided at a second end portion of the blade portion in the lateral direction opposite to the first end portion, the second end portion including a free end.

[0135] In a cross section orthogonal to the longitudinal direction, the contact portion includes:

[0136] a first portion 811 extending in a first direction A21 along the lateral direction and contacting the developer carrying member, and

[0137] a second portion 812 extending from an end portion Dl of the first portion on a side of the free end in a second direction A22 intersecting the first direction toward the free end such that the second portion gets farther from the surface of the developer carrying member as it progresses toward the free end.

[0138] when an area divided by connecting an end portion D2 of the second portion on a side of the free end, the end portion Dl of the first portion, and an intersection point in the second direction with a straight line is defined as a first area,

[0139] In the longitudinal direction of the blade portion, the area of the first region on the longitudinal end portion of the blade portion is smaller than the area of the first region on the longitudinal central portion of the blade portion, the intersection point being where an imaginary line B1 orthogonal to the first direction and passing through the end portion D2 of the second portion intersects an extension line B2 of the first portion in the first direction.

[0140] (2) In the developing device according to the present application,

[0141] The second portion 812 can be formed by performing a polishing operation on the second end portion of the blade portion 81.

[0142] (3) In the developing device according to the present application,

[0143] When the polishing operation is performed,

[0144] When, on the longitudinal central portion of the blade portion 81, the amount of scraping in the thickness direction A3 of the blade portion 81 is Pt1 and the amount of scraping in the lateral direction A2 is Ps1, and

[0145] When, on the longitudinal end portion of the blade portion 81, the amount of scraping in the thickness direction A3 of the blade portion is Pt2 and the amount of scraping in the lateral direction A2 is Ps2,

[0146] Ps1>Ps2, and

[0147] Pt1>Pt2.

[0148] (4) In the developing device according to the present application,

[0149] On the longitudinal end portion of the blade portion 81, the amount of scraping Ps2 in the lateral direction A2 decreases toward the outside in the longitudinal direction A1.

[0150] (5) In the developing device according to the present application,

[0151] On the longitudinal end portion of the blade portion 81, the amount of scraping Pt2 in the thickness direction A3 decreases toward the outside in the longitudinal direction A1.

[0152] (6) The developing device according to the present application can include:

[0153] The supply member 5 is configured to contact the developer bearing member 4 and supply the developer to the developer bearing member.

[0154] In the longitudinal direction A1, the longitudinal end portion is located outside the area where the supply member contacts the developer bearing member 4, and

[0155] In the longitudinal direction A1, the longitudinal central portion is located inside the area where the supply member contacts the developer bearing member 4.

[0156] (7) In the developing apparatus according to the present application,

[0157] The developing apparatus 3 can be configured to be attached to and detached from the image forming apparatus 100.

[0158] (8) A restricting member 8 according to the present application includes:

[0159] a blade portion 81 extending in a longitudinal direction Al, and

[0160] a support portion 82 supporting a first end portion of the blade portion in a lateral direction A2 orthogonal to the longitudinal direction.

[0161] A contact portion 810 for contacting a surface of a developer bearing member is provided at a second end portion of the blade portion in the lateral direction opposite to the first end portion, the second end portion including a free end.

[0162] In a cross section orthogonal to the longitudinal direction, the contact portion includes:

[0163] a first portion 811 extending in a first direction A21 along the lateral direction and contacting the developer bearing member, and

[0164] a second portion 812 extending from an end portion Dl of the first portion on a side of the free end in a second direction A22 intersecting the first direction toward the free end such that the second portion gets farther from the surface of the developer bearing member as it progresses toward the free end.

[0165] When an area divided by connecting an end portion D2 of the second portion on a side of the free end, the end portion Dl of the first portion, and an intersection point in the second direction with a straight line is defined as a first area,

[0166] In the longitudinal direction of the blade portion, an area of the first area on a longitudinal end portion of the blade portion is smaller than an area of the first area on a longitudinal central portion of the blade portion, the intersection point being where an imaginary line Bl passing through the end portion D2 of the second portion orthogonal to the first direction intersects an extension line B2 of the first portion in the first direction.

[0167] (9) A process cartridge 7 according to the present application includes:

[0168] an image bearing member 1 configured to bear an image; and

[0169] a developing apparatus 3 or a restricting member 8, and

[0170] the process cartridge is attached to and detached from the image forming apparatus 100.

[0171] (10) An image forming apparatus 100 according to the present application includes:

[0172] a fixing member 34; and

[0173] the developing device 3, the regulating member 8, or the process cartridge 7, and

[0174] The image forming apparatus forms an image on a recording material P.

[0175] According to the present application, uniformity in the longitudinal direction of the developer layer carried by the developer carrying member is increased, while the use efficiency of raw materials at the time of manufacture is improved.

[0176] While the application has been described with reference to example embodiments, it is to be understood that the application is not limited to the disclosed example embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all the equivalents and alternatives.

Claims

1. A developing apparatus comprising: a developer bearing member configured to bear a developer; and a restricting member configured to restrict a thickness of a layer of the developer on the developer bearing member, wherein the restricting member includes: a blade portion extending in a longitudinal direction, and a support portion supporting a first end portion of the blade portion in a lateral direction orthogonal to the longitudinal direction, wherein a contact portion for contacting a surface of the developer bearing member is provided at a second end portion of the blade portion in the lateral direction opposite to the first end portion in the lateral direction, the second end portion including a free end, wherein, in a cross section orthogonal to the longitudinal direction, the contact portion includes: a first surface extending in the lateral direction and contacting the developer bearing member, a third surface extending in a thickness direction of the blade portion, the thickness direction being orthogonal to both the longitudinal direction and the lateral direction, and a second surface extending from an end portion of the first surface on a side of the free end in a direction intersecting the lateral direction toward the free end, connecting the first surface and the third surface, and extending in the direction intersecting the lateral direction, such that as the second surface advances toward the free end, the second surface is farther away from the surface of the developer bearing member and a thickness of the contact portion in the thickness direction of the blade portion decreases, and wherein, in the cross section orthogonal to the longitudinal direction, when an area divided by connecting the end portion of the second surface on the side of the free end in the direction intersecting the lateral direction, the end portion of the first surface, and an intersection point with a straight line is defined as a first area, in the longitudinal direction of the blade portion, the intersection point is where an imaginary line orthogonal to the lateral direction and passing through the end portion of the second surface intersects an extension line of the first surface in the lateral direction, an area of the first area in a first cross section on a longitudinal end portion of the blade portion is smaller than an area of the first area in a second cross section on a longitudinal central portion of the blade portion, wherein, when, on the longitudinal central portion of the blade portion, a distance between the intersection point and the first surface in the lateral direction is Ps1, a distance between the intersection point and the second surface in the thickness direction is Pt1, and when, on the longitudinal end portion of the blade portion, a distance between the intersection point and the first surface in the lateral direction is Ps2, a distance between the intersection point and the second surface in the thickness direction is Pt2, Ps1 > Ps2, and Pt1 > Pt2.

2. The developing apparatus according to claim 1, wherein the second surface is formed by performing a polishing operation on the second end portion of the blade portion.

3. The developing apparatus according to claim 2, wherein, when the polishing operation is performed, Ps1 is a shaving amount in the lateral direction and Pt1 is a shaving amount in a thickness direction of the blade portion on a longitudinal central portion of the blade portion, and Ps2 is a shaving amount in the lateral direction and Pt2 is a shaving amount in a thickness direction of the blade portion on a longitudinal end portion of the blade portion.

4. The developing apparatus according to claim 3, wherein, the shaving amount Ps2 in the lateral direction on the longitudinal end portion of the blade portion decreases toward the outside in the longitudinal direction.

5. The developing apparatus according to claim 4, wherein the shaving amount Pt2 in the thickness direction on the longitudinal end portion of the blade portion decreases toward the outside in the longitudinal direction.

6. The developing apparatus according to claim 1, further comprising: a supply member configured to contact the developer bearing member and supply a developer to the developer bearing member, wherein, in the longitudinal direction, the longitudinal end portion is outside an area in which the supply member contacts the developer bearing member, and wherein, in the longitudinal direction, the longitudinal central portion is inside the area in which the supply member contacts the developer bearing member.

7. The developing apparatus according to claim 1, wherein the developing apparatus is attachable to and detachable from an image forming apparatus.

8. A restriction member comprising: a blade portion extending in a longitudinal direction, and a support portion supporting a first end portion of the blade portion in a lateral direction orthogonal to the longitudinal direction, wherein a contact portion for contacting a surface of a developer bearing member configured to bear a developer is provided at a second end portion of the blade portion in the lateral direction opposite to the first end portion in the lateral direction, the second end portion including a free end, wherein, in a cross section orthogonal to the longitudinal direction, the contact portion includes: a first surface extending in the lateral direction and contacting the developer bearing member, a third surface extending in a thickness direction of the blade portion, the thickness direction being orthogonal to both the longitudinal direction and the lateral direction, and a second surface extending from an end portion of the first surface on a side of the free end in a direction intersecting the lateral direction toward the free end, connecting the first surface and the third surface, and extending in the direction intersecting the lateral direction such that the second surface is farther away from the surface of the developer bearing member and a thickness of the contact portion in the thickness direction of the blade portion decreases as the second surface advances toward the free end, and wherein, in a cross section orthogonal to the longitudinal direction, when an area divided by connecting end portions of the second surface on one side of the free end in the direction intersecting the lateral direction, the end portions of the first surface, and an intersection point with a straight line passing through the end portions of the second surface orthogonal to the lateral direction is defined as a first area, the intersection point is a point where the straight line and an extension line of the first surface in the lateral direction intersect, an area of the first area in a first cross section on a longitudinal end portion of the blade portion is smaller than an area of the first area in a second cross section on a longitudinal central portion of the blade portion, wherein, when, on the longitudinal central portion of the blade portion, a distance between the intersection point and the first surface in the lateral direction is Ps1, a distance between the intersection point and the second surface in the thickness direction is Pt1, and when, on the longitudinal end portion of the blade portion, a distance between the intersection point and the first surface in the lateral direction is Ps2, a distance between the intersection point and the second surface in the thickness direction is Pt2, Ps1>Ps2, and Pt1>Pt2.

9. A process cartridge, comprising: an image bearing member configured to bear an image; and the developing device according to any one of claims 1 to 7, wherein the process cartridge is attachable to and detachable from an image forming apparatus.

10. An image forming apparatus, comprising: a fixing member; and the developing device according to any one of claims 1 to 7, wherein the image forming apparatus forms an image on a recording material.

11. A process cartridge, comprising: an image bearing member configured to bear an image; and the restricting member according to claim 8, wherein the process cartridge is attachable to and detachable from an image forming apparatus.

12. An image forming apparatus, comprising: a fixing member; and the restricting member according to claim 8, wherein the image forming apparatus forms an image on a recording material.

13. An image forming apparatus, comprising: a fixing member; and the process cartridge according to claim 9, wherein the image forming apparatus forms an image on a recording material.

Images