Developer and image forming apparatus

Abstract

A developer and an image forming apparatus, the developer including: a developer holding body provided in a portion other than an end portion with a suction region that is a region in which a developer containing toner and a carrier is sucked, the developer holding body holding the developer supplied to an image holding body forming an electrostatic latent image in the suction region; a magnetic plate located in a second range other than a first range in the circumferential direction at the end portion of the developer holding body; and magnets which are combined to form a magnetization pattern in the circumferential direction corresponding to the first range.

Description

Technical Field

[0001] The present invention relates to a developer and an image forming device. Background Art

[0002] For example, Patent Document 1 discloses a developing device comprising: a developer container filled with developer; a developing sleeve having a built-in magnet and rotatably mounted on an opening of the developer container to transport the developer to an electrostatic latent image formed on a photosensitive body; a magnetic sealing component having multipolar magnetized NS poles on the inner circumference and arranged at both ends of the developing sleeve at a predetermined distance from the outer circumference of the developing sleeve, wherein the developing device is characterized in that the NS poles multipolar magnetized on the inner circumference are magnetized obliquely relative to the length direction of the developing sleeve.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2004-354855 Summary of the invention

[0004] Here, in a developer holder that has an adsorption area as an area for adsorbing developer containing toner and carrier by internal arrangement of magnets and holds the developer supplied to the image holder forming the electrostatic latent image in the adsorption area, the inside and outside of the developer may be contaminated by toner leakage at the end where the magnet is not arranged inside. In order to prevent the toner leakage, it is conceivable to configure a structure in which a magnet and a magnetic plate are additionally arranged at the end of the developer holder. However, depending on the structure of the end, it is sometimes difficult to additionally configure at least one of the magnet and the magnetic plate around the entire circumference of the end, in which case, it is necessary to change the constituent parts.

[0005] An object of the present invention is to suppress an increase in cost for preventing toner leakage, compared with a case where components are changed in order to arrange magnets and magnetic plates around the entire circumference of an end portion.

[0006] The invention described in Scheme 1 is a developer, comprising: a developer retaining body, which has an adsorption area as an area for adsorbing a developer containing a colorant and a carrier at a portion other than an end portion, and retains the developer supplied to an image retaining body that forms an electrostatic latent image in the adsorption area; a magnetic plate, which is located in a second range other than the first range in the circumferential direction at the end portion of the developer retaining body; and a magnet, which is combined to form a magnetization pattern in the circumferential direction corresponding to the first range.

[0007] The invention described in claim 2 is characterized in that in the developer described in claim 1, the magnetization pattern changes a plurality of times in the circumferential direction.

[0008] The invention described in claim 3 is characterized in that in the developer described in claim 1 or 2, at least a portion of the magnetization pattern within the first range is formed by arranging magnetic poles of magnets in the circumferential direction of the developer holding body.

[0009] The invention described in claim 4 is characterized in that in the developer described in claim 1 or 2, at least a portion of the magnetization pattern within the second range is formed by arranging the magnetic poles of the magnet in the axial direction of the developer holding body.

[0010] The invention described in Scheme 5 is characterized in that in the developer described in Scheme 4, the magnet whose magnetic poles are arranged in the axial direction is arranged at the upstream and downstream ends of the circumferential direction of the developer retaining body and is arranged at a position close to the magnetic plate.

[0011] The invention described in claim 6 is characterized in that in the developer according to any one of claims 2 to 4, the magnet forming the magnetization pattern within the first range and the magnet forming the magnetization pattern within the second range are in contact with each other.

[0012] The invention described in Scheme 7 is characterized in that in the developer described in Scheme 2, at least a portion of the magnetization pattern within the first range is formed by a first circumferential arrangement, wherein the first circumferential arrangement arranges the magnetic poles of magnets in the circumferential direction, and at least a portion of the magnetization pattern within the second range is formed by a second circumferential arrangement, wherein the magnetic poles of magnets are arranged in the circumferential direction and the axial position of the magnets is different from that of the magnets in the first circumferential arrangement.

[0013] The invention described in Scheme 8 is characterized in that in the developer described in Scheme 2, at least a portion of the magnetization pattern within the first range is formed by arranging the magnetic poles of the magnet in the first direction, and at least a portion of the magnetization pattern within the second range is formed by arranging the magnetic poles of the magnet in a second direction different from the first direction.

[0014] The invention described in claim 9 is characterized in that in the developer described in claim 8, the first direction is the circumferential direction of the developer holding body, and the second direction is the axial direction of the developer holding body.

[0015] The invention described in claim 10 is characterized in that in the developer described in claim 8, the first direction is the circumferential direction of the developer holding body, and the second direction is a direction intersecting the circumferential direction and the axial direction of the developer holding body.

[0016] The invention described in Scheme 11 in the developer described in Scheme 8 is characterized in that the first direction is a first intersecting direction that intersects with the circumferential direction of the developer retaining body and the axial direction of the developer retaining body, and the second direction is a second intersecting direction that intersects with the circumferential direction, the axial direction and the first intersecting direction.

[0017] The invention described in Scheme 12 is an image forming device, which includes: an image holder that forms an electrostatic latent image; a developing component that develops the electrostatic latent image formed by the image holder into a colorant image; a transfer component that transfers the colorant image developed by the developing component to a recording material; and a fixing component that fixes the colorant image transferred to the recording material to the recording material, the developing component comprising: a developer holder that has an adsorption area provided in a portion other than an end portion as an area for adsorbing a developer containing a colorant and a carrier, and that holds the developer supplied to the image holder that forms the electrostatic latent image in the adsorption area; a magnetic plate that is located in a second range other than the first range in the circumferential direction at the end portion of the developer holder; and a magnet that is combined to form a magnetized pattern in the circumferential direction corresponding to the first range.

[0018] Effects of the Invention

[0019] According to the first aspect of the present invention, it is possible to suppress an increase in cost for preventing toner leakage, compared with a case where components are changed in order to arrange magnets and magnetic plates around the entire circumference of the end portion.

[0020] According to the second aspect of the present invention, compared with a case where the structure in which the magnetization pattern changes a plurality of times in the circumferential direction is not provided, it is possible to more reliably prevent toner leakage.

[0021] According to the third aspect of the present invention, it is possible to suppress an increase in starting torque compared to a case where at least a portion of the magnetization pattern within the first range is not formed by arranging the magnetic poles of the magnets in the circumferential direction of the developer holding member.

[0022] According to the fourth aspect of the present invention, compared with a structure in which at least a part of the magnetization pattern in the second range is not formed by arranging the magnetic poles of the magnets in the axial direction of the developer holding member, it is possible to more reliably prevent toner leakage in the axial direction.

[0023] According to the fifth scheme of the present invention, compared with a structure that does not have a structure in which magnets with axially arranged magnetic poles are arranged at the upstream and downstream ends of the circumferential direction of the developer retaining body and arranged at positions close to the magnetic plate, it is possible to more reliably prevent colorant leakage in the circumferential direction.

[0024] According to the sixth aspect of the present invention, toner leakage can be prevented more reliably than in a case where the magnet forming the magnetization pattern within the first range and the magnet forming the magnetization pattern within the second range are not in contact with each other.

[0025] According to the seventh scheme of the present invention, compared to a structure in which at least a portion of the magnetization pattern within the first range is formed by the first circumferential arrangement, and the first circumferential arrangement has the magnetic poles of the magnets arranged in the circumferential direction, and at least a portion of the magnetization pattern within the second range is formed by the second circumferential arrangement, and the second circumferential arrangement has the magnetic poles of the magnets arranged in the circumferential direction, and the axial position of the magnets is different from that of the first circumferential arrangement, it is possible to more reliably prevent colorant leakage.

[0026] According to the 8th scheme of the present invention, compared with a structure in which at least a part of the magnetization pattern within the first range is formed by arranging the magnetic poles of magnets in the first direction, and at least a part of the magnetization pattern within the second range is formed by arranging the magnetic poles of magnets in a second direction different from the first direction, it is possible to more reliably prevent colorant leakage.

[0027] According to the ninth aspect of the present invention, compared with a case where the first direction is not the circumferential direction of the developer holding member and the second direction is the axial direction of the developer holding member, toner leakage can be prevented more reliably.

[0028] According to the tenth aspect of the present invention, compared with a configuration in which the first direction is the circumferential direction of the developer holding member and the second direction is a direction intersecting the circumferential direction and the axial direction of the developer holding member, toner leakage can be prevented more reliably.

[0029] According to the 11th scheme of the present invention, compared with a structure in which the first direction is not the first intersecting direction intersecting the circumferential direction of the developer retaining body and the axial direction of the developer retaining body, and the second direction is the second intersecting direction intersecting the circumferential direction, the axial direction and the first intersecting direction, colorant leakage can be prevented more reliably.

[0030] According to the twelfth aspect of the present invention, compared with the case where the components are changed in order to arrange the magnets and the magnetic plate around the entire circumference of the end portion, it is possible to suppress an increase in cost for preventing toner leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0032] Figure 1 is a diagram illustrating an image forming apparatus;

[0033] Figure 2 is a diagram illustrating a developer of an image forming apparatus;

[0034] Figure 3 is a perspective view illustrating a more specific structure of the developer;

[0035] Figure 4 is a cross-sectional view of the developer as viewed from the inner surface side of the front side component;

[0036] Figure 5 is a cross-sectional view illustrating the relationship between the developing roller, the metal plate, and the sheet magnet;

[0037] Figure 6 is a perspective view illustrating the relationship between the developing roller, the metal plate and the sheet magnet;

[0038] Figure 7 is a diagram illustrating a first embodiment of a magnetization pattern;

[0039] Figure 8 is a diagram illustrating a second embodiment of a magnetization pattern;

[0040] Fig. 9 is a diagram illustrating a third embodiment of a magnetization pattern;

[0041] Fig.10 It is a diagram for explaining the fourth embodiment example of the magnetization pattern.

[0042] Explanation of symbols

[0043] 1-image forming device, 31-photosensitive drum, 33-developer, 50a, 50b-area, 51, 52-metal plate, 60-magnetization pattern, 61-first magnetization pattern portion, 61a, 62a-magnet portion, 61b, 62b-end, 62-second magnetization pattern portion, 334-developing roller, J-axial direction, Ja-outer side, N, N1, N2-oblique direction, S-circumferential direction, Sa-one direction. DETAILED DESCRIPTION

[0044] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0045] Figure 1 It is a diagram for explaining the image forming apparatus 1 .

[0046] The image forming apparatus 1 according to the present embodiment includes a paper feeding unit 1A, a printing unit 1B, and a paper discharge unit 1C.

[0047] The paper feeding unit 1A includes first to fourth paper accommodating sections 11 to 14 for accommodating paper P as an example of recording media.

[0048] The paper feeding unit 1A is provided corresponding to the first to fourth paper accommodating portions 11 to 14 , respectively, and is provided with delivery rollers 15 to 18 for delivering the paper P accommodated in each paper accommodating portion to a transport path connected to the printing unit 1B.

[0049] The printing unit 1B includes an image forming section 20 that forms an image on the paper P. The printing unit 1B is also provided with a control section 21 that controls each section of the image forming apparatus 1 .

[0050] Furthermore, the printing unit 1B includes an image processing unit 22 . The image processing unit 22 performs image processing on image data sent from the image reading device 4 or the personal computer (PC) 5 .

[0051] Furthermore, the printing unit 1B is provided with a UI (User Interface) 23 which is constituted by a touch panel or the like and which notifies information to the user and accepts input of information from the user.

[0052] The image forming section 20 as an example of an image forming member includes six image forming units 30T, 30P, 30Y, 30M, 30C, and 30K (hereinafter, sometimes simply referred to as “image forming units 30 ”) arranged in parallel at predetermined intervals.

[0053] Each image forming unit 30 includes a photosensitive drum 31 that forms an electrostatic latent image while rotating in the direction of arrow A, a charging roller 32 that charges the surface of the photosensitive drum 31, a developer 33 that develops the electrostatic latent image formed on the photosensitive drum 31, and a drum cleaner 34 that removes colorant and the like on the surface of the photosensitive drum 31.

[0054] The photosensitive drum 31 is an example of an image holding member.

[0055] Furthermore, the image forming section 20 is provided with a laser exposure device 26 for exposing the photosensitive drum 31 of each image forming unit 30 with a laser beam.

[0056] The exposure of the photosensitive drum 31 by the laser exposure device 26 is not limited to that by the laser beam. For example, a light source such as an LED (Light Emitting Diode) may be provided for each image forming unit 30, and the photosensitive drum 31 may be exposed using light emitted from the light source.

[0057] The image forming units 30 have the same structure except for the toner stored in the developer 33. The image forming units 30Y, 30M, 30C, and 30K form yellow (Y), magenta (M), cyan (C), and black (K) toner images, respectively.

[0058] The image forming units 30T and 30P form toner images using toner corresponding to the corporate color, foaming toner for Braille, fluorescent toner, gloss-enhancing toner, etc. In other words, the image forming units 30T and 30P form toner images using special color toner.

[0059] Furthermore, the image forming section 20 is provided with an intermediate transfer belt 41 for transferring the toner images of the respective colors formed on the photosensitive drums 31 of the respective image forming units 30 .

[0060] Furthermore, the image forming section 20 is provided with a primary transfer roller 42 that transfers the color toner images of the image forming units 30 onto the intermediate transfer belt 41 at the primary transfer section T1 .

[0061] The image forming section 20 is provided with a secondary transfer roller 40 that transfers the toner image transferred onto the intermediate transfer belt 41 onto the paper P at the secondary transfer section T2 .

[0062] Furthermore, the image forming section 20 is provided with a belt cleaner 45 for removing toner and the like on the surface of the intermediate transfer belt 41 , and a fixing device 80 for fixing the secondarily transferred image to the paper P.

[0063] The image forming section 20 performs an image forming operation according to a control signal from the control section 21 .

[0064] Specifically, in the image forming unit 20 , first, the image processing unit 22 performs image processing on the image data input from the image reading device 4 or the PC 5 , and the image data after the image processing is supplied to the laser exposure device 26 .

[0065] Then, for example, in the magenta (M) image forming unit 30M, after the surface of the photosensitive drum 31 is charged by the charging roller 32 , the photosensitive drum 31 is irradiated with a laser beam modulated by image data obtained from the image processing section 22 by the laser exposure device 26 .

[0066] Thus, an electrostatic latent image is formed on the photosensitive drum 31 .

[0067] The formed electrostatic latent image is developed by the developer 33 , so that a magenta toner image is formed on the photosensitive drum 31 .

[0068] Similarly, yellow, cyan, and black toner images are formed in the image forming units 30Y, 30C, and 30K, and special color toner images are formed in the image forming units 30T and 30P.

[0069] The toner images of the respective colors formed in the respective image forming units 30 are electrostatically transferred to the primary transfer rollers 42 in sequence. Figure 1 A toner image superimposed on the intermediate transfer belt 41 is formed on the intermediate transfer belt 41 rotating in the direction of arrow C.

[0070] The superimposed toner images formed on the intermediate transfer belt 41 are conveyed to the secondary transfer portion T2 constituted by the secondary transfer roller 40 and the backup roller 49 as the intermediate transfer belt 41 moves.

[0071] On the other hand, after being taken out from the first paper storage unit 11 by the delivery roller 15 , for example, the paper P is transported to the position of the registration roller 74 via the transport path.

[0072] When the superimposed toner images are conveyed to the secondary transfer portion T2 , the paper P is supplied from the registration roller 74 to the secondary transfer portion T2 at the timing.

[0073] Then, the superimposed toner images are electrostatically transferred onto the paper P at a secondary transfer portion T2 by the action of a transfer electric field formed between the secondary transfer roller 40 and the backup roller 49 .

[0074] Then, the paper P to which the superimposed toner images are electrostatically transferred is conveyed to the fixing device 80 .

[0075] In the fixing device 80 , the paper P on which the unfixed toner image is formed is pressed and heated, and a fixing process of the toner image on the paper P is performed.

[0076] Then, the paper P that has been subjected to the fixing process passes through a curl correction section 81 provided in the paper discharge unit 1C, and is then conveyed to a paper stacking section (not shown).

[0077] Figure 2 It is a diagram for explaining the developing device 33 of the image forming apparatus 1 .

[0078] The developing device 33 includes a housing portion 331 that houses a developer (not shown) therein. The housing portion 331 is composed of a housing frame 332 made of resin.

[0079] The housing frame 332 of the developer 33 is arranged along the Figure 2 The direction extending from the image forming device 1 (reference Figure 1 ) is oriented toward the rear side, and has a front side member 33a (reference Figure 3 ), and has an inner part 33b at the rear side (reference Figure 3 ).

[0080] The accommodating frame 332 is in contact with the photosensitive drum 31 (refer to Figure 1 ) is provided at a position opposite to the photosensitive drum 31. The opening 333 is provided with a developing roller 334 that allows the developer to adhere to the surface of the photosensitive drum 31.

[0081] The developing roller 334 as an example of a developer holding member is formed in a cylindrical shape and is arranged to extend in a direction from the front side to the rear side of the image forming apparatus 1. In other words, the developing roller 334 is arranged along the longitudinal direction of the developing device 33.

[0082] The developing roller 334 includes a developing sleeve 334A which is formed of a cylindrical body and is driven to rotate, and a magnet roller 334B which is arranged inside the developing sleeve 334A.

[0083] The developing sleeve 334A is made of metal such as SUS, for example, and rotates in the direction of arrow D in the figure.

[0084] The developing roller 334 is an example of a developer holding member.

[0085] Furthermore, in the present embodiment, at the primary transfer portion T1 (refer to Figure 1 ), the developing sleeve 334A and the photosensitive drum 31 rotate in such a manner that the developing sleeve 334A and the photosensitive drum 31 move in the same direction.

[0086] The developing device 33 is provided with a layer regulating member 335 that regulates the layer thickness of the developer held by the developing roller 334 .

[0087] And, if Figure 2 As shown, the developing device 33 is provided with a first transport member 336 and a second transport member 337 for transporting the developer.

[0088] The first conveying member 336 and the second conveying member 337 are disposed with the developing roller 334 interposed therebetween and at a position adjacent to the photosensitive drum 31 (see Figure 1 ) on the side opposite to the side of the ).

[0089] The first conveying member 336 includes a rotation axis along the rotation axis of the development sleeve 334A that is rotationally driven, and rotates around the rotation axis to convey the developer in the accommodating portion 331 .

[0090] In the developer 33 thus configured, new toner or toner to which a very small amount of carrier is added is circulated and transported by being stirred and transported between the first transport member 336 and the second transport member 337. More specifically, by transferring the developer through the connection ports formed at both ends of the partition extending in the axial direction, the developer stirred by the first transport member 336 can be stirred by the second transport member 337, and further stirred by the first transport member 336. A circulation path is formed in the developer 33, and the circulation path is a path that circulates in the axial direction by the rotation of the first transport member 336 and the second transport member 337.

[0091] The developing device 33 is provided with a third conveying member 338 adjacent to the second conveying member 337 . Furthermore, the developing device 33 is provided with a pickup roller 339 located above the third conveying member 338 .

[0092] The conveying path formed by the rotation of the third conveying member 338 is connected to the above-mentioned circulation path, and the developer from the circulation path is transferred. The third conveying member 338 supplies the developer to the pickup roller 339. The pickup roller 339 supplies the developer to the developing roller 334.

[0093] For example, the first transport member 336 transports toward the front side of the paper surface, the second transport member 337 transports toward the back side of the paper surface, and the third transport member 338 transports toward the front side of the paper surface.

[0094] The developing roller 334, the layer regulating member 335, the first transport member 336, the second transport member 337, the third transport member 338, and the pickup roller 339 are arranged to be aligned with the photosensitive drum 31 (see FIG. Figure 1 ) are roughly parallel.

[0095] Next, a more specific structure of the developing device 33 will be described.

[0096] Figure 3 33 is a perspective view for explaining a more specific structure of the developing device 33. Figure 3 , the removal of the pickup roller 339 (reference Figure 2 ) after the status.

[0097] like Figure 3 As shown, as a structure of the receiving frame 332 (reference Figure 2 ), the developer 33 has a front side component 33a located at the front side and a back side component 33b located at the back side. The front side component 33a and the back side component 33b are spaced apart in the axial direction J of the developing roller 334. The ends of the developing roller 334 are held by the front side component 33a and the back side component 33b so as to be rotatable.

[0098] The inner surface 33c of the front side member 33a faces the back side member 33b, and the outer surface 33d is a surface located on the opposite side to the back side member 33b.

[0099] Figure 4 33 is a cross-sectional view of the developing device 33 as viewed from the inner surface 33c side of the front side component 33a, and shows the periphery of the developing roller 334 in an enlarged manner. Figure 4 In the figure, the first transport member 336 is omitted.

[0100] like Figure 4As shown, the developing device 33 includes a cover member 33 e having a portion with an arc-shaped cross section that covers a portion of the developing roller 334 .

[0101] The developer 33 is provided with magnetic metal plates 51 and 52 and a sheet magnet 53 on the front side member 33a. The metal plates 51 and 52 are arranged at different positions in the vertical direction, with the metal plate 51 being located at the upper side and the metal plate 52 being located at the lower side.

[0102] The metal plates 51 and 52 are provided on the inner surface 33c of the front member 33a adjacent to the developing roller 334. More specifically, the metal plate 51 is located near the cover member 33e, and the metal plate 52 is located between the first transport member 336 and the developing roller 334.

[0103] The sheet magnet 53 is provided along the circumferential direction S of the developing roller 334. The sheet magnet 53 has a portion located in the circumferential direction S between the metal plates 51 and 52.

[0104] A magnetic pattern is formed on the metal plates 51 and 52 by the magnetic force of the developing roller 334. The sheet magnet 53 has a magnetic pattern in one predetermined direction.

[0105] The magnetic pattern mentioned here indicates the range of magnetic force, which is the N / S pole boundary / arrangement.

[0106] In addition, the metal plates 51 and 52 and the sheet magnet 53 may be provided at positions close to the developing roller 334 , and the gap therebetween may be set to, for example, 1 mm.

[0107] Figure 5 and Figure 6 3 is a diagram for explaining the relationship between the developing roller 334, the metal plates 51, 52 and the sheet magnet 53. Figure 5 is its cross-sectional view, Figure 6 It is a stereogram.

[0108] like Figure 5 As shown in FIG. 1 , the metal plate 51 is provided on the inner surface 33c of the front side member 33a. That is, the metal plate 51 is located at the end of the developing roller 334. Figure 5 In the embodiment, the metal plate 52 is omitted (refer to Figure 4 ) in the figure, but is located at the end of the developing roller 334 in the same manner as the metal plate 51.

[0109] exist Figure 5 In FIG. 1 , the front side member 33 a is shown in cross section, and the portion of the developing roller 334 that protrudes beyond the front side member 33 a is omitted.

[0110] The sheet magnet 53 is provided in the recess 33f formed in the front side member 33a. More specifically, the sheet magnet 53 is located between the inner surface of the recess 33f and the developing roller 334. The sheet magnet 53 is provided on the entire circumference of the developing roller 334.

[0111] To further explain, the concave portion 33f is located closer to the end than the metal plate 51 in the axial direction J of the developing roller 334. Therefore, the sheet magnet 53 is located closer to the end than the metal plate 51 ( Figure 5 center left position).

[0112] exist Figure 6 In FIG. 5 , the magnetization pattern of the sheet magnet 53 is shown by a thick line, and the flow of the toner in the suspended state is shown by a dotted arrow at the end of the developing roller 334. Figure 6 In the figure, the portion on the front side of the front side member 33a is omitted.

[0113] Figure 6 The sheet magnets 53 shown are provided in the circumferential direction S in a region 50 a where the metal plates 51 and 52 are located and in a region where the metal plates 51 and 52 are not located (ie, a region 50 b other than the region 50 a ).

[0114] The region 50a is an example of the second range, and the region 50b is an example of the first range.

[0115] The sheet magnet 53 has a magnetization pattern 60 that changes multiple times in the circumferential direction S. The magnetization pattern 60 is formed by combining magnets, is a range of magnetic force, and indicates the boundary and arrangement of the N pole and the S pole.

[0116] More specifically, the magnetization pattern 60 has a first magnetization pattern portion 61 formed by arranging the magnetic poles of the magnets in the circumferential direction S in the region 50b where the metal plates 51 and 52 do not exist. Furthermore, the magnetization pattern 60 has a second magnetization pattern portion 62 formed by arranging the magnetic poles of the magnets in the axial direction J in the regions 50a and 50b.

[0117] As described above, when the magnetization pattern 60 is focused on in one direction in the circumferential direction S, the second magnetization pattern portion 62 , the first magnetization pattern portion 61 , and the second magnetization pattern portion 62 are arranged in this order, and thus multiple changes occur.

[0118] To further explain, the region 50b is provided with the first magnetization pattern portion 61 in the circumferential direction S, instead of the second magnetization pattern portion 62 in the axial direction J. Therefore, even if the toner in the suspended state moves from the region 50b where the metal plates 51 and 52 are not present to the outer side Ja in the axial direction J, the movement in the axial direction J is hindered by the magnetic field generated by the first magnetization pattern portion 61. Furthermore, even if the toner in the suspended state moves in one direction Sa in the circumferential direction S at the first magnetization pattern portion 61, the movement in the axial direction J is hindered by the magnetic field generated by the second magnetization pattern portion 62.

[0119] This prevents the toner in the suspended state from leaking to the developer 33 (for example, see Figure 2 ) outside. In addition, the one direction Sa on the circumferential direction S mentioned here includes the radial direction and is a direction other than the axial direction J. That is, when the axial direction J is called the lateral direction, the one direction Sa can be called the longitudinal direction.

[0120] exist Figure 6 In the embodiment, the entire magnetization pattern 60 (first magnetization pattern portion 61) in the region 50b where the metal plates 51 and 52 do not exist is formed by arranging the magnetic poles of the sheet magnet 53 in the circumferential direction S, but the present invention is not limited to this. That is, when taking measures against the toner in the suspended state, it is also possible to form at least a part of the magnetization pattern 60 in the region 50b by the first magnetization pattern portion 61.

[0121] Furthermore, by arranging the magnetic poles of the sheet magnet 53 in the axial direction J, a magnetization pattern 60 (second magnetization pattern portion 62) is formed within the region 50a where the metal plates 51 and 52 are located, but this is not limited to this, and it is also conceivable that at least a portion of the magnetization pattern 60 within the region 50a is formed by the second magnetization pattern portion 62.

[0122] Here, if Figure 6 As shown, the second magnetized pattern portion 62 of the sheet magnet 53 in which the magnetic poles of the sheet magnet 53 are arranged in the axial direction J is arranged at the most upstream and downstream of the developing roller 334 in the circumferential direction S and is arranged close to the metal plates 51 and 52. Thus, leakage of the toner in the circumferential direction S is prevented.

[0123] In addition, in the case of the conventional developing device 33 including the sheet magnet, by replacing it with the sheet magnet 53 according to the present embodiment, it is possible to suppress toner leakage and reduce the design change cost.

[0124] Furthermore, in the present embodiment, since the magnetic force of the magnet is used, the increase in the starting torque can be suppressed compared to the case where a sealing member such as sponge is used to prevent toner leakage.

[0125] [Various Forms of Magnetization Pattern 60]

[0126] Next, use Figure 7 to Figure 10 Various forms of the magnetization pattern 60 will be described.

[0127] Figure 7 It is a diagram for explaining a first embodiment example of the magnetization pattern 60 .

[0128] In the magnetization pattern 60, the first magnetization pattern portion 61 is formed by stacking magnet portions 61a formed in layers. And the second magnetization pattern portion 62 is formed by stacking magnet portions 62a formed in layers. The magnet portions 61a and 62a correspond to Figure 6 Thick lines shown.

[0129] like Figure 7 As shown, the magnetization pattern 60 according to the first embodiment includes the first magnetization pattern portion 61 and the second magnetization pattern portion 62. The magnet portion 61a in the first magnetization pattern portion 61 extends along the circumferential direction S and is stacked in the axial direction J. The magnet portion 62a in the second magnetization pattern portion 62 extends along the axial direction J and is stacked in the radial direction.

[0130] Therefore, if the toner in the suspended state moves toward the outer side Ja through the area 50b between the metal plate 51 and the metal plate 52 to the sheet magnet 53, the movement toward the outer side Ja is blocked by the magnet portion 61a of the first magnetization pattern portion 61. The toner in the suspended state whose movement is blocked moves in one direction Sa, but it does not leak out of the developer due to the stopper structure formed by the magnet portion 62a of the second magnetization pattern portion 62 and the structure in which the path length is lengthened. In addition, the leakage of the toner to the outside of the developer 33 is suppressed not only by the magnetization pattern 60, but also by the developer gathered by the magnetization pattern 60.

[0131] If further explanation is given, Figure 7 In the first embodiment shown, the magnet portion 62a of the second magnetization pattern portion 62 contacts the magnet portion 61a of the first magnetization pattern portion 61. That is, the magnet portion 62a contacts the end portion 61b of the magnet portion 61a. Thus, toner leakage in the axial direction J is more reliably suppressed.

[0132] In the first embodiment, the magnet portion 62a is in contact with the end portion 61b of the magnet portion 61a, but a non-contact structure may be adopted. Even in this case, leakage to the outside of the developer can be suppressed by the magnetic force of the magnet portion 62a.

[0133] So, in Figure 7In the first embodiment shown, the magnetization pattern 60 for the region 50b where the metal plates 51 and 52 are not present is formed by combining the first magnetization pattern portion 61 having a longitudinal magnetization pattern by the magnet portion 61a and the second magnetization pattern portion 62 having a transverse magnetization pattern by the magnet portion 62a. The magnetization pattern 60 suppresses the leakage of the suspended toner in the axial direction J and the circumferential direction S through the region 50b.

[0134] The magnetization pattern 60 of the first embodiment changes multiple times in the circumferential direction S, and at least a portion of the region 50b is formed by arranging the magnetic poles of the magnet portion 61a in the circumferential direction S. In addition, in the magnetization pattern 60, at least a portion of the region 50a is formed by arranging the magnetic poles of the magnet portion 62a in the axial direction J.

[0135] The circumferential direction S in the first embodiment is an example of a first direction, and the axial direction J is an example of a second direction.

[0136] Figure 8 It is a figure explaining the 2nd form example of the magnetization pattern 60. In the 2nd form example, the same code|symbol is used for the same structure as the 1st form example, and the description is abbreviate|omitted sometimes.

[0137] like Figure 8 As shown, in the second embodiment, the magnet portion 62a of the second magnetization pattern portion 62 extends along the circumferential direction S similarly to the magnet portion 61a of the first magnetization pattern portion 61 and is stacked in the axial direction J. The second embodiment differs from the first embodiment in this respect.

[0138] To further explain, the magnet portion 62a is different from the magnet portion 61a in the axial direction J. That is, the magnet portion 62a is located at a position offset from the magnet portion 61a in the axial direction J, rather than being located at the same position as the magnet portion 61a in the axial direction J.

[0139] Therefore, the toner in a suspended state whose movement to the outer side Ja is blocked by the magnet portion 61 a of the first magnetization pattern portion 61 is prevented from leaking out of the developer by the magnetic force generated by the magnet portion 62 a of the second magnetization pattern portion 62 .

[0140] So, in Figure 8 In the second embodiment shown, the magnetization pattern 60 for the region 50b where the metal plates 51 and 52 are not present is formed by combining the first magnetization pattern portion 61 having a longitudinal magnetization pattern and the second magnetization pattern portion 62 having a longitudinal magnetization pattern offset from the first magnetization pattern portion 61 in the axial direction J. The magnetization pattern 60 suppresses leakage of the suspended toner in the axial direction J and the circumferential direction S through the region 50b.

[0141] The magnetization pattern 60 of the second embodiment changes multiple times in the circumferential direction S, and at least a portion of the region 50 b where the metal plates 51 and 52 do not exist is formed by arranging the magnetic poles of the magnet portion 61 a in the circumferential direction S.

[0142] More specifically, at least a portion of the magnetization pattern 60 in the region 50b is formed by a first circumferential arrangement in which the magnetic poles of the magnet portion 61a are arranged in the circumferential direction S. Furthermore, at least a portion of the magnetization pattern 60 in the region 50a where the metal plates 51 and 52 are located is formed by a second circumferential arrangement in which the magnetic poles of the magnet portion 62a are arranged in the circumferential direction S and the position in the axial direction J is different from that of the magnet portion 61a of the first circumferential arrangement.

[0143] Fig. 9 It is a diagram for explaining a third embodiment of the magnetization pattern 60 .

[0144] like Fig. 9 As shown in FIG. 1 , in the third embodiment, the magnet portion 62 a of the second magnetization pattern portion 62 extends along the oblique direction N which is a direction inclined with respect to the axial direction J. As shown in FIG.

[0145] The third embodiment is different from the first and second embodiments described above in this respect.

[0146] To further explain, the magnet portion 61a of the first magnetization pattern portion 61 and the magnet portion 62a of the second magnetization pattern portion 62 are in contact with each other. That is, the second magnetization pattern portion 62 is positioned relative to the first magnetization pattern portion 61 in such a manner that the end portion 62b of the magnet portion 62a is connected to the end portion 61b of the magnet portion 61a. Thus, the toner leakage in the axial direction J is more reliably prevented.

[0147] In the third embodiment, the end 62b of the magnet portion 62a is in contact with the end 61b of the magnet portion 61a, but a non-contact structure may be adopted. Even in this case, leakage to the outside of the developer can be suppressed by the magnetic force of the magnet portion 62a.

[0148] So, in Fig. 9 In the third embodiment shown, the magnetization pattern 60 for the region 50b where the metal plates 51 and 52 are not present is formed by combining the first magnetization pattern portion 61 having a longitudinal magnetization pattern and the second magnetization pattern portion 62 having a magnetization pattern oriented obliquely downward with respect to the axial direction J. The magnetization pattern 60 suppresses leakage of the suspended toner in the axial direction J and the circumferential direction S through the region 50b.

[0149] The magnetization pattern 60 of the third embodiment changes in the circumferential direction S a plurality of times.

[0150] Furthermore, in the third embodiment, at least a portion of the magnetization pattern 60 in the region 50b is formed by arranging the magnetic poles of the magnet portion 61a in the circumferential direction S, and at least a portion of the magnetization pattern 60 in the region 50a is formed by arranging the magnetic poles of the magnet portion 62a in an oblique direction N different from the circumferential direction S. The oblique direction N different from the circumferential direction S here refers to a direction intersecting the circumferential direction S and the axial direction J.

[0151] The circumferential direction S in the third embodiment is an example of the first direction, and the oblique direction N is an example of the second direction.

[0152] Fig.10 It is a diagram for explaining a fourth embodiment of the magnetization pattern 60 .

[0153] like Fig.10 As shown, in the fourth embodiment, the magnet portion 61a of the first magnetization pattern portion 61 extends along the oblique direction N1 relative to the axial direction J, and the magnet portion 62a of the second magnetization pattern portion 62 extends along the oblique direction N2 relative to the axial direction J. Furthermore, the oblique direction N1 and the oblique direction N2 extend in directions intersecting each other.

[0154] Therefore, the toner in a suspended state that advances from the region 50 b toward the outer side Ja is prevented from leaking to the outside of the developing device by the magnet portion 61 a and the magnet portion 62 a .

[0155] To further explain, in the fourth embodiment, the end 61b of the magnet portion 61a of the first magnetization pattern portion 61 and the end 62b of the magnet portion 62a of the second magnetization pattern portion 62 are in contact with each other. This more reliably prevents toner leakage in the axial direction J.

[0156] In the fourth embodiment, the end 62b of the magnet portion 62a is in contact with the end 61b of the magnet portion 61a, but a non-contact structure may be adopted. Even in this case, the leakage to the outside of the developer can be suppressed by the magnetic force of the magnet portions 61a and 62a.

[0157] So, in Fig.10 In the fourth form example shown, the magnetization pattern 60 is formed by combining a first magnetization pattern portion 61 having a magnetization pattern with an oblique direction N1 directed obliquely upward relative to the axial direction J and a second magnetization pattern portion 62 having a magnetization pattern with an oblique direction N2 directed obliquely downward relative to the axial direction J, thereby suppressing the leakage of suspended colorant in the axial direction J and the circumferential direction S through the area 50b.

[0158] In the fourth embodiment, at least a portion of the magnetization pattern 60 within the region 50b is formed by arranging the magnetic poles of the magnet portion 61a in a direction (oblique N1) intersecting the circumferential direction S and the axial direction J, and at least a portion of the magnetization pattern 60 within the region 50a is formed by arranging the magnetic poles of the magnet portion 62a in a direction (oblique N2) intersecting the circumferential direction S and the axial direction J and also intersecting the magnetic pole direction of the magnet portion 61a.

[0159] In the fourth embodiment, the oblique direction N1 is an example of the first direction and an example of the first intersecting direction. Also, the oblique direction N2 is an example of the second direction and an example of the second intersecting direction.

[0160] In addition, if Fig.10 As shown, the magnetization pattern 60 involved in the fourth embodiment has a first magnetization pattern portion 61 disposed on the upper side of the inner surface of the semicircular shape, and a second magnetization pattern portion 62 disposed on the lower side. In other words, in the fourth embodiment, when the magnetization pattern 60 is divided by a horizontal plane including the center point for observation, the first magnetization pattern portion 61 is disposed on the inner surface of the upper semicircular shape, and the second magnetization pattern portion 62 is disposed on the inner surface of the lower semicircular shape, but the present invention is not limited thereto. That is, when the magnetization pattern 60 is divided by a vertical plane including the center point for observation of the two longitudinal semicircular shapes, it is also possible to Fig.10 The inner surface of any one of the longitudinal semicircular shapes is formed as shown, and the inner surface of the other longitudinal semicircular shape is formed to be upside down with the inner surface of the longitudinal semicircular shape. The upside-down structure mentioned here refers to an example in which a second magnetization pattern portion 62 is arranged on the upper side and a first magnetization pattern portion 61 is arranged on the lower side. In the case of this configuration example, the magnetization pattern 60 changes multiple times in the circumferential direction S.

[0161] <Note>

[0162] (1) A developer comprising:

[0163] A developer holding body having an adsorption region as a region for adsorbing a developer containing a toner and a carrier, at a portion other than an end portion, and holding the developer supplied to an image holding body on which an electrostatic latent image is formed, in the adsorption region;

[0164] a magnetic plate located in a second range excluding the first range in the circumferential direction at the end of the developer holding body; and

[0165] The magnets are combined to form a magnetization pattern in the circumferential direction corresponding to the first range.

[0166] (2) The developer according to (1), characterized in that:

[0167] The magnetization pattern changes multiple times in the circumferential direction.

[0168] (3) The developer according to (1) or (2), characterized in that:

[0169] At least a portion of the magnetization pattern within the first range is formed by arranging magnetic poles of magnets in the circumferential direction of the developer holding member.

[0170] (4) The developer according to (1) or (2), characterized in that:

[0171] At least a portion of the magnetization pattern within the second range is formed by arranging magnetic poles of magnets in the axial direction of the developer holding member.

[0172] (5) The developer according to (4), characterized in that:

[0173] The magnets whose magnetic poles are arranged in the axial direction are arranged most upstream and most downstream in the circumferential direction of the developer holding body and are arranged at positions close to the magnetic plate.

[0174] (6) The developer according to any one of (2) to (4), characterized in that:

[0175] The magnet forming the magnetization pattern within the first range and the magnet forming the magnetization pattern within the second range are in contact with each other.

[0176] (7) The developer according to (2), characterized in that:

[0177] At least a portion of the magnetization pattern within the first range is formed by a first circumferential arrangement, wherein the first circumferential arrangement arranges the magnetic poles of the magnets in the circumferential direction.

[0178] At least a portion of the magnetization pattern within the second range is formed by a second circumferential arrangement in which magnetic poles of magnets are arranged in the circumferential direction and whose axial positions are different from those of the magnets in the first circumferential arrangement.

[0179] (8) The developer according to (2), characterized in that:

[0180] At least a portion of the magnetization pattern within the first range is formed by arranging magnetic poles of magnets in a first direction.

[0181] At least a portion of the magnetization pattern within the second range is formed by arranging magnetic poles of magnets in a second direction different from the first direction.

[0182] (9) The developer according to (8), characterized in that:

[0183] The first direction is the circumferential direction of the developer holding body,

[0184] The second direction is the axial direction of the developer holding member.

[0185] (10) The developer according to (8), characterized in that:

[0186] The first direction is the circumferential direction of the developer holding body,

[0187] The second direction is a direction intersecting the circumferential direction and the axial direction of the developer holding member.

[0188] (11) The developer according to (8), characterized in that:

[0189] The first direction is a first intersecting direction intersecting the circumferential direction of the developer holding body and the axial direction of the developer holding body,

[0190] The second direction is a second intersecting direction intersecting the circumferential direction, the axial direction, and the first intersecting direction.

[0191] (12) An image forming apparatus comprising:

[0192] An image holding body for forming an electrostatic latent image;

[0193] a developing member that develops the electrostatic latent image formed by the image holding member into a toner image;

[0194] a transfer member that transfers the toner image developed by the developing member onto a recording material; and

[0195] a fixing member that fixes the toner image transferred onto the recording material onto the recording material,

[0196] The developing member comprises:

[0197] A developer holding body having an adsorption region as a region for adsorbing a developer containing a toner and a carrier, at a portion other than an end portion, and holding the developer supplied to an image holding body on which an electrostatic latent image is formed, in the adsorption region;

[0198] a magnetic plate located in a second range excluding the first range in the circumferential direction at the end of the developer holding body; and

[0199] The magnets are combined to form a magnetization pattern in the circumferential direction corresponding to the first range.

[0200] According to the invention of (1), compared with the case where the components are changed in order to arrange the magnets and the magnetic plate around the entire circumference of the end portion, it is possible to suppress an increase in cost for preventing toner leakage.

[0201] According to the invention of (2), compared with a case where the structure in which the magnetization pattern changes a plurality of times in the circumferential direction is not provided, it is possible to more reliably prevent toner leakage.

[0202] According to the invention of (3), compared with a case where at least a portion of the magnetization pattern in the first range is not formed by arranging the magnetic poles of the magnet in the circumferential direction of the developer holding member, an increase in the starting torque can be suppressed.

[0203] According to the invention of (4), compared with a structure in which at least a part of the magnetization pattern in the second range is not formed by arranging the magnetic poles of the magnets in the axial direction of the developer holding member, it is possible to more reliably prevent the toner leakage in the axial direction.

[0204] According to the invention of (5), compared with a structure that does not have a structure in which magnets with axially arranged magnetic poles are arranged at the upstream and downstream ends of the developer retaining body in the circumferential direction and arranged at positions close to the magnetic plate, it is possible to more reliably prevent colorant leakage in the circumferential direction.

[0205] According to the invention of (6), toner leakage can be prevented more reliably than in a case where the magnet forming the magnetization pattern within the first range and the magnet forming the magnetization pattern within the second range are not in contact with each other.

[0206] According to the invention of (7), compared with a structure in which at least a portion of the magnetization pattern within the first range is formed by the first circumferential arrangement, and the first circumferential arrangement has the magnetic poles of the magnets arranged in the circumferential direction, and at least a portion of the magnetization pattern within the second range is formed by the second circumferential arrangement, and the second circumferential arrangement has the magnetic poles of the magnets arranged in the circumferential direction, and the axial position of the magnets is different from that of the first circumferential arrangement, it is possible to more reliably prevent colorant leakage.

[0207] According to the invention of (8), compared with a structure in which at least a portion of the magnetization pattern within the first range is formed by arranging the magnetic poles of magnets in the first direction, and at least a portion of the magnetization pattern within the second range is formed by arranging the magnetic poles of magnets in a second direction different from the first direction, colorant leakage can be prevented more reliably.

[0208] According to the invention of (9), compared with a case where the first direction is not the circumferential direction of the developer holding member and the second direction is the axial direction of the developer holding member, it is possible to more reliably prevent toner leakage.

[0209] According to the invention of (10), compared with a case where the first direction is not the circumferential direction of the developer holding member and the second direction is a direction intersecting the circumferential direction and the axial direction of the developer holding member, toner leakage can be prevented more reliably.

[0210] According to the invention of (11), compared with a structure in which the first direction is a first intersecting direction intersecting the circumferential direction of the developer retaining body and the axial direction of the developer retaining body, and the second direction is a second intersecting direction intersecting the circumferential direction, the axial direction and the first intersecting direction, colorant leakage can be prevented more reliably.

[0211] According to the invention of (12), compared with the case where the components are changed in order to arrange the magnets and the magnetic plate around the entire circumference of the end portion, the increase in cost for preventing the toner leakage can be suppressed.

[0212] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles of the present invention and its application. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A developer, comprising: A developer holding body having a suction region as a region for sucking a developer containing a toner and a carrier, at a portion other than an end portion, and holding the developer supplied to an image holding body on which an electrostatic latent image is formed, in the suction region; a magnetic plate located in a second range excluding the first range in the circumferential direction at the end of the developer holding body; and The magnets are combined to form a magnetization pattern in the circumferential direction corresponding to the first range.

2. The developer according to claim 1, characterized in that: The magnetization pattern changes multiple times in the circumferential direction.

3. The developer according to claim 1 or 2, characterized in that: At least a portion of the magnetization pattern within the first range is formed by arranging magnetic poles of magnets in the circumferential direction of the developer holding member.

4. The developer according to claim 1 or 2, characterized in that: At least a portion of the magnetization pattern within the second range is formed by arranging magnetic poles of magnets in the axial direction of the developer holding member.

5. The developer according to claim 4, characterized in that: The magnets whose magnetic poles are arranged in the axial direction are arranged most upstream and most downstream in the circumferential direction of the developer holding body and are arranged at positions close to the magnetic plate.

6. The developer according to any one of claims 2 to 4, characterized in that: The magnet forming the magnetization pattern within the first range and the magnet forming the magnetization pattern within the second range are in contact with each other.

7. The developer according to claim 2, characterized in that: At least a portion of the magnetization pattern within the first range is formed by a first circumferential arrangement, wherein the first circumferential arrangement arranges the magnetic poles of the magnets in the circumferential direction. At least a portion of the magnetization pattern within the second range is formed by a second circumferential arrangement in which magnetic poles of magnets are arranged in the circumferential direction and whose axial positions are different from those of the magnets in the first circumferential arrangement.

8. The developer according to claim 2, characterized in that: At least a portion of the magnetization pattern within the first range is formed by arranging magnetic poles of magnets in a first direction. At least a portion of the magnetization pattern within the second range is formed by arranging magnetic poles of magnets in a second direction different from the first direction.

9. The developer according to claim 8, characterized in that: The first direction is the circumferential direction of the developer holding body, The second direction is the axial direction of the developer holding member.

10. The developer according to claim 8, characterized in that: The first direction is the circumferential direction of the developer holding body, The second direction is a direction intersecting the circumferential direction and the axial direction of the developer holding member.

11. The developer according to claim 8, characterized in that: The first direction is a first intersecting direction intersecting the circumferential direction of the developer holding body and the axial direction of the developer holding body, The second direction is a second intersecting direction intersecting the circumferential direction, the axial direction, and the first intersecting direction.

12. An image forming apparatus, comprising: An image holding body for forming an electrostatic latent image; a developing member for developing the electrostatic latent image formed by the image holding member into a toner image; a transfer member for transferring the toner image developed by the developing member onto a recording material; and a fixing member that fixes the toner image transferred onto the recording material onto the recording material, The developing member comprises: A developer holding body having a suction region as a region for sucking a developer containing a toner and a carrier, at a portion other than an end portion, and holding the developer supplied to an image holding body on which an electrostatic latent image is formed, in the suction region; a magnetic plate located in a second range excluding the first range in the circumferential direction at the end of the developer holding body; and The magnets are combined to form a magnetization pattern in the circumferential direction corresponding to the first range.

Images