Developer and image forming apparatus

Abstract

The invention discloses a developing device and an image forming apparatus, the developing device includes: a developer holding body that holds a developer containing a toner and a carrier, that is, the developer supplied to an image holding body that forms an electrostatic latent image; a cover member that covers a portion of the developer holding body; and a film which is a film in which an end portion in a circumferential direction of the developer holding body is attached to the cover member and which is in contact with the developer held by the developer holding body, and which is also attached to the cover member at a position in the middle in the circumferential direction.

Description

Technical Field

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

[0002] For example, in Japanese Patent Gazette No. 2016-139111, a developing device is disclosed, which includes a developer carrier, a developer limiting component, and a shell component arranged opposite to a latent image carrier, wherein the device includes: a first shielding component, one end of which is retained on the shell component, and the other end of which contacts the surface of the latent image carrier at a position on the upstream side of the surface movement direction of the latent image carrier relative to the developing area; a second shielding component, one end of which is retained on the shell component's opposite surface to the developer carrier, and the other end of which contacts the first shielding component at a position on the upstream side of the surface movement direction of the developer carrier relative to the developing area; and a third shielding component, one end of which is retained on the shell component's opposite surface to the developer carrier, and the other end of which droops due to its own weight and contacts the developer on the developer carrier passing through the limiting position based on the developer limiting component at a position on the upstream side of the surface movement direction of the developer carrier relative to the developing area. Summary of the invention

[0003] Here, it is considered that a covering member is provided to cover a part of the developer holding body to prevent the toner from floating around the developer holding body that holds the developer containing the toner and the carrier and contaminating the surroundings. When the toner accumulates on the side of the covering member that is opposite to the developer holding body and forms a mass, the mass may fall off the covering member and cause image defects. In the case where the occurrence of the mass is suppressed by providing a film that contacts the developer held by the developer holding body on the covering member, if it is not difficult to maintain the contact state of the film and the developer layer, the toner may accumulate.

[0004] An object of the present invention is to prevent a situation in which it is difficult to maintain a contact state between a film and a developer layer of a developer holding member, and to suppress the occurrence of toner accumulation compared with a case in which such a structure is not adopted.

[0005] According to a first aspect of the present invention, a developer is provided, comprising: a developer retaining body, which retains a developer containing a colorant and a carrier, i.e., the developer supplied to an image retaining body for forming an electrostatic latent image; a covering member, which covers a portion of the developer retaining body; and a film, wherein the end portions of the developer retaining body in the circumferential direction are mounted on the covering member and are in contact with the developer retained by the developer retaining body, and the film is also mounted on the covering member at a middle position in the circumferential direction.

[0006] According to a second aspect of the present invention, in the developer based on the first aspect, the middle position on the film is set based on the height of the layer of developer adsorbed by the developer adsorbing magnet possessed by the developer retaining body.

[0007] According to a third aspect of the present invention, in the developer according to the second aspect, the intermediate position based on the setting includes a position corresponding to a position of the attracting magnet where a height of the developer layer is high.

[0008] According to a fourth aspect of the present invention, in the developer based on the third aspect, in the intermediate position based on the setting, the position between the attracting magnets where the height of the developer layer is lower than the position of the attracting magnet is not included.

[0009] According to a fifth aspect of the present invention, in the developer according to the first or second aspect, the film mounted on the covering member is curved in a shape following a change in height of the layer of the developer throughout the circumference of the developer holding body.

[0010] According to the sixth aspect of the present invention, in the developer based on any one of the first to fifth aspects, the middle position of the film is the center position of the film in the circumferential direction, and the film is installed at the center position of the covering part in the circumferential direction.

[0011] According to a seventh aspect of the present invention, in the developer according to any one of the first to sixth aspects, the cover member has a mark indicating a position of the middle position where the film is attached on a surface facing the developer holding body.

[0012] According to an eighth aspect of the present invention, in the developer according to the seventh aspect, the mark is a linear mark extending along the longitudinal direction of the cover member.

[0013] According to the ninth aspect of the present invention, in the developer based on the eighth aspect, the linear mark is not formed in the area of ​​the covering part corresponding to the end of the developer retaining body where the developer adsorbing magnet possessed by the developer retaining body is not provided.

[0014] According to the tenth aspect of the present invention, an image forming device is provided, which includes: an image retaining body, which forms an electrostatic latent image; a developing unit, which develops the electrostatic latent image formed on the image retaining body into a colorant image; a transfer unit, which transfers the colorant image of the developing unit to a recording material; and a fixing unit, which fixes the colorant image transferred to the recording material on the recording material, the developing unit comprising: a developer retaining body, which retains a developer containing a colorant and a carrier, i.e., the developer supplied to the image retaining body that forms the electrostatic latent image; a covering member, which covers a portion of the developer retaining body; and a film, which is a film that is mounted on the covering member at the end portion of the developer retaining body in the circumferential direction and is in contact with the developer retained by the developer retaining body, and is also mounted on the covering member at the middle position in the circumferential direction.

[0015] (Effect)

[0016] According to the first aspect, there is no situation in which it is difficult to maintain the contact state between the film and the developer layer of the developer holding member, and the occurrence of toner accumulation can be suppressed compared to a case in which this structure is not adopted.

[0017] According to the second aspect, the position of the middle of the film is set based on the height of the developer layer attracted by the developer attracting magnet of the developer holding member, and the occurrence of toner accumulation can be suppressed compared to a case without this structure.

[0018] According to the third aspect, since the set intermediate position includes the position corresponding to the position of the attraction magnet where the height of the developer layer is high, the occurrence of toner accumulation can be suppressed compared to a case without this configuration.

[0019] According to the fourth aspect, at the set intermediate position, the position between the attracting magnets where the height of the layer not including the developer is lower than the position of the attracting magnet can suppress the occurrence of toner accumulation compared to a case without this structure.

[0020] According to the fifth aspect, the film attached to the covering member is curved in a shape following the change in height of the developer layer in the circumferential direction of the developer holding member, and the occurrence of toner accumulation can be suppressed compared to a case without this structure.

[0021] According to the sixth aspect, the film whose middle position is the circumferential center of the film is attached to the circumferential center of the covering member, which is applicable regardless of the rotation direction of the developer retaining member, compared with a case without such a structure.

[0022] According to the seventh aspect, the cover member has a mark indicating the position of the middle position where the film is attached on the surface facing the developer holding body, and the assembly workability can be improved compared to a case without this structure.

[0023] According to the eighth aspect, the mark is a linear mark extending in the longitudinal direction of the covering member, and the assembly workability can be improved compared to a case where this structure is not provided.

[0024] According to the ninth aspect, no linear mark is formed in the area of ​​the covering part corresponding to the end of the developer retaining body where the developer attracting magnet of the developer retaining body is not provided, which can improve the assembly workability compared with the case without this structure.

[0025] According to the tenth aspect, a situation in which it is difficult to maintain the contact state between the film and the developer layer of the developer holding member does not occur, and the occurrence of toner accumulation can be suppressed compared to a case in which this structure is not adopted. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A diagram for explaining an image forming apparatus;

[0027] Figure 2 A diagram for explaining a developing device of an image forming device;

[0028] Figure 3 is a perspective view illustrating a more specific structure of the developing device;

[0029] Figure 4 A diagram illustrating the magnetic poles of the magnetic roller of the developing roller;

[0030] Figure 5 A diagram illustrating a film provided on the inner surface of a cover member;

[0031] Figure 6 This is a diagram for explaining the sticking position of the film with respect to the cover member. Figure 6 (a) indicates that the pasting position is a preset position. Figure 6 (b) indicates a case where the pasting position is offset from a preset position;

[0032] Figure 7 It is a perspective view showing the inner surface of the cover member. DETAILED DESCRIPTION

[0033] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] Figure 1 This is a diagram for explaining the image forming apparatus 1 .

[0035] The image forming apparatus 1 of the present embodiment includes a paper feeding unit 1A, a printing unit 1B, and a paper discharge unit 1C.

[0036] 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.

[0037] The paper feeding unit 1A is provided with delivery rollers 15 to 18 , which are provided corresponding to the first to fourth paper accommodating sections 11 to 14 , respectively, and deliver the paper P accommodated in each paper accommodating section to a conveying path connected to the printing unit 1B.

[0038] 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 .

[0039] The printing unit 1B also 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 .

[0040] The printing unit 1B is also provided with a UI (User Interface) 23 which is composed of a touch panel or the like and which notifies information to the user and receives information input from the user.

[0041] The image forming unit 20 as an example of an image forming unit 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 regular intervals.

[0042] 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.

[0043] The photosensitive drum 31 is an example of an image holding member.

[0044] 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 to laser light.

[0045] The exposure of the photosensitive drum 31 by the laser exposure device 26 is not limited to that by laser. For example, a light source such as an LED (Light Emitting Diode) may be provided in each image forming unit 30, and the photosensitive drum 31 may be exposed using light emitted from the light source.

[0046] The image forming units 30 are similarly configured except for the toner stored in the developing device 33. The image forming units 30Y, 30M, 30C, and 30K form toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

[0047] The image forming units 30T and 30P form toner images using toner corresponding to 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 toner of special color.

[0048] In addition, the image forming section 20 is provided with an intermediate transfer belt 41 to which the toner images of the respective colors formed on the photosensitive drums 31 of the respective image forming units 30 are transferred.

[0049] 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 via the primary transfer section T1 .

[0050] In addition, 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 .

[0051] 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 on the paper P.

[0052] The image forming section 20 performs an image forming operation based on a control signal from the control section 21 .

[0053] Specifically, in the image forming unit 20 , first, image processing is performed by the image processing unit 22 on 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 .

[0054] Then, for example, in the magenta (M) image forming unit 30M, the surface of the photosensitive drum 31 is charged by the charging roller 32 , and then the laser exposure device 26 irradiates the photosensitive drum 31 with laser light modulated by the image data obtained from the image processing section 22 .

[0055] Thus, an electrostatic latent image is formed on the photosensitive drum 31 .

[0056] The formed electrostatic latent image is developed by the developing device 33 , and a magenta toner image is formed on the photosensitive drum 31 .

[0057] Similarly, the image forming units 30Y, 30C, and 30K form yellow, cyan, and black toner images, and the image forming units 30T and 30P form special color toner images.

[0058] The color toner images formed in the image forming units 30 are electrostatically transferred to the surfaces along the image forming units 30 in sequence by the primary transfer rollers 42. Figure 1 On the intermediate transfer belt 41 rotating in the direction of arrow C, overlapping toner images are formed on the intermediate transfer belt 41.

[0059] 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.

[0060] On the other hand, the paper P is taken out from the first paper storage unit 11 by, for example, the delivery roller 15 , and then transported to the position of the registration roller 74 via the transport path.

[0061] 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.

[0062] Then, in the secondary transfer portion T2 , the superimposed toner images are electrostatically transferred onto the paper P at a time by the action of a transfer electric field formed between the secondary transfer roller 40 and the backup roller 49 .

[0063] Thereafter, the paper P to which the superimposed toner images are electrostatically transferred is conveyed to the fixing device 80 .

[0064] 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.

[0065] Then, the paper P 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 loading section (not shown).

[0066] Figure 2 2 is a diagram for explaining the developing device 33 of the image forming apparatus 1. Figure 2 The developer 33 is shown as viewed from the back side.

[0067] 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.

[0068] The housing frame 332 of the developer 33 is arranged along the direction from the image forming apparatus 1 (see Figure 1 ) is facing the dorsal direction, that is, Figure 2It is configured so as to extend in a direction perpendicular to the paper surface, and has a back side end portion not shown in the figure on the back side and a front side end portion not shown in the figure on the front side.

[0069] On the accommodating frame 332, the photosensitive drum 31 (see Figure 1 ) is provided at a position facing the photosensitive drum 31. In the opening 333, a developing roller 334 is provided to make the developer adhere to the surface of the photosensitive drum 31.

[0070] 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 back 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.

[0071] The developing roller 334 is provided with a developing sleeve 334A which is constituted by a cylindrical body and is driven to rotate, and a magnetic roller 334B which is arranged on the inner side of the developing sleeve 334A.

[0072] The developing sleeve 334A is made of metal such as SUS, etc. The developing sleeve 334A rotates in the direction of arrow D in the figure.

[0073] The developing roller 334 is an example of a developer holding member.

[0074] Furthermore, in this embodiment, in the roller gap (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.

[0075] 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 .

[0076] In addition, if Figure 2 As shown, the developing device 33 is provided with a first conveying member 336 and a second conveying member 337 for conveying the developer.

[0077] The first conveying member 336 and the second conveying member 337 are disposed with the developing roller 334 interposed therebetween. Figure 1 The side opposite to the side where the reference is set).

[0078] The first conveying member 336 includes a rotation shaft along the rotation shaft of the development sleeve 334A that is rotationally driven, and rotates around the rotation shaft to convey the developer in the storage section 331 .

[0079] In the developer 33 thus constructed, the toner added with new toner or a very small amount of carrier is circulated and transported by being stirred and transported between the first transport member 336 and the second transport member 337. More specifically, the developer is delivered through the connection ports formed at both ends of the partition wall along the axial direction, and the developer stirred by the first transport member 336 is stirred by the second transport member 337, and can also be stirred by the first transport member 336. A path, that is, a circulation path, which circulates in the axial direction by the rotation of the first transport member 336 and the second transport member 337 is formed in the developer 33.

[0080] The developing device 33 is provided with a third transport member 338 adjacent to the second transport member 337. In addition, the developing device 33 is provided with a pickup roller 339 located above the third transport member 338.

[0081] The transport path formed by the rotation of the third transport member 338 is connected to the above-mentioned circulation path, and the developer from the circulation path is delivered. The third transport member 338 supplies the developer to the pickup roller 339. The pickup roller 339 supplies the developer to the developing roller 334.

[0082] For example, the first conveying member 336 conveys toward the front side of the paper surface, the second conveying member 337 conveys toward the back side of the paper surface, and the third conveying member 338 conveys toward the front side of the paper surface.

[0083] 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 connected to the photosensitive drum 31 (see FIG. Figure 1 ) are arranged roughly in parallel.

[0084] Next, a more specific structure of the developing device 33 will be described.

[0085] Figure 3 33 is a perspective view for explaining a more specific structure of the developing device 33. Figure 3 Sometimes the Figure 2 The symbols shown are the same as those of the parts in the description.

[0086] like Figure 3 As shown, the developing device 33 includes a cover member 51 having a portion 51a having an arc-shaped cross section that covers a portion of the pickup roller 339. The cover member 51 is a member for preventing toner from floating and causing contamination, and is an example of a covering member.

[0087] Here, Figure 4 This is a diagram for explaining the magnetic pole of the magnetic roller 334B of the developing roller 334 .

[0088] like Figure 4As shown in FIG. 1 , the magnetic roller 334B is provided with a plurality of magnetic poles arranged in the circumferential direction. More specifically, the magnetic roller 334B is provided with seven magnetic poles 61a to 67a. Figure 4 As shown in the figure, there are line segment 61 indicating the position of the first magnetic pole 61a, line segment 62 indicating the position of the second magnetic pole 62a, line segment 63 indicating the position of the third magnetic pole 63a, line segment 64 indicating the position of the fourth magnetic pole 64a, line segment 65 indicating the position of the fifth magnetic pole 65a, line segment 66 indicating the position of the sixth magnetic pole 66a and line segment 67 indicating the position of the seventh magnetic pole 67a.

[0089] The magnetic attraction distribution 60 in the normal direction indicated by the thick line is set by configuring the magnetic poles 61a to 67a. The magnetic attraction distribution 60 indicates that the thickness of the developer layer, that is, the height of the layer from the surface of the developing roller 334, changes according to the position of the developing roller 334 in the circumferential direction S. Figure 4 As shown, the magnetic attraction force distribution 60 has a high developer layer at positions of line segments 64 and 65 where magnetic poles 64a and 65a are located, and a low developer layer between adjacent magnetic poles 64a and 65a, such as between line segments 64 and 65.

[0090] In this way, the height of the developer layer on the developing roller 334 varies in the circumferential direction S.

[0091] The magnetic poles 64a and 65a are examples of attraction magnets.

[0092] Figure 5 This is a diagram for explaining the film 52 provided on the inner surface 51 b of the cover member 51 .

[0093] like Figure 5 As shown, a film 52 is provided on the inner surface 51 b of the cover member 51 .

[0094] The film 52 is provided on the inner surface 51 b of the cover member 51 by attaching the adhesive tape 53 to the end portion 52 a of the film 52 and attaching the adhesive tape 54 to the end portion 52 b .

[0095] The film 52 is preferably a soft member with no hardness. The film 52 can be made of, for example, a urethane-based material, and has a thickness of, for example, 50 to 200 μm.

[0096] In the film 52, an adhesive tape 55 is attached to a middle portion 52c located between the end portion 52a and the end portion 52b in the circumferential direction S of the developing roller 334. The position of the middle portion 52c is an example of a middle position in the circumferential direction.

[0097] The adhesive tapes 53 to 55 are double-sided adhesive tapes having adhesive surfaces on both sides, and are all located between the inner surface 51b of the cover member 51 and the film 52. Therefore, the film 52 is located between the cover member 51 in the circumferential direction of the developing roller 334, and no gap is formed between the film 52 and the cover member 51 into which toner can penetrate.

[0098] To further explain, the end portion 52b to which the adhesive tape 54 is attached is the position of the line segment 64, and the middle portion 52c to which the adhesive tape 55 is attached is the position of the line segment 65. Furthermore, at the position where the adhesive tapes 54 and 55 are attached, the distance between the developing roller 334 and the film 52 is long, and at the middle position, the distance is short.

[0099] In this way, the adhesive tapes 54 and 55 are attached to the higher position of the developer layer, thereby ensuring the distance between the developing roller 334 and the film 52. More specifically, the film 52 is attached not only to the adhesive tapes 53 and 54 at the end portions 52a and 52b, but also to the adhesive tape 55 at the position corresponding to the line segment 65, that is, the middle portion 52c, so that even if the height of the developer layer changes in the circumferential direction, the film 52 is in light contact with the developer layer.

[0100] Therefore, it is possible to prevent the toner accumulated on the inner surface 51b side of the cover member 51 from becoming agglomerated and falling onto the developing roller 334 (see Figure 3 ) and the like, resulting in image defects.

[0101] In addition, in the present embodiment, the middle portion 52c to which the adhesive tape 55 is attached is one location, but the present invention is not limited thereto and may be a plurality of locations.

[0102] Here, the middle portion 52c of the film 52 is installed at the line segment 65 ( Figure 4 The portion of the film 52 at the position of the cover member 51 corresponding to the fifth magnetic pole 65a) shown in FIG. 1 may be located at the center of the film 52 or may be offset from the center. The center here refers to the center of the film 52 on the cover member 51 in the same direction as the circumferential direction S of the cross-sectional arc-shaped portion 51a.

[0103] In addition, the magnetic attraction distribution 60 (refer to Figure 4 ) is used as the basis for setting the position of the middle portion 52c of the film 52, and determining whether to set the middle portion 52c to the center of the film 52. In the case of the center of the film 52, the curved shapes of the film 52 on the upstream and downstream sides of the middle portion 52c in the direction of arrow D can be set to be the same.

[0104] To further explain, the middle portion 52c of the film 52 is provided at a position where the film 52 is lightly in contact with the developer layer. Therefore, for example, a position where the height not including the developer layer is lower than the height of the developer layer of the fourth magnetic pole 64a and the fifth magnetic pole 65a, such as between the fourth magnetic pole 64a and the fifth magnetic pole 65a, is also considered. In addition, as a position where the middle portion 52c is offset from the above-mentioned position where the developer layer is higher, a case where the middle portion 52c includes the above-mentioned position where the developer layer is lower is also considered.

[0105] Furthermore, when there are a plurality of intermediate portions 52 c , it is considered that in addition to the position where the developer layer is high, there are also positions where the developer layer is lower than the position.

[0106] Figure 6 2 is a diagram for explaining the sticking position of the film 52 with respect to the cover member 51. Figure 6 (a) indicates that the pasting position is a preset position. Figure 6 (b) shows the case where the pasting position is offset from the preset position. Figure 6 The developer layer is represented by an elliptical shape.

[0107] like Figure 6 As shown in (a), if the film 52 is attached to the positions of the above-mentioned end portions 52a and 52b by means of adhesive tapes 53 and 54, and attached to the position of the middle portion 52c at a predetermined position by means of adhesive tape 55, the film 52 becomes a curved shape that is consistent with the height of the developer layer. That is, the film 52 is curved to follow the change in the height of the developer layer throughout the circumference of the developing roller 334.

[0108] The predetermined position here refers to the position of the middle portion 52c of the film 52, and is in contact with the line segment 65 (for example, see Figure 6 The position of (a) corresponds to the center position of the arc-shaped cross-section of the cover member 51 in the circumferential direction S.

[0109] On the other hand, Figure 6 As shown in (b), when the film 52 is attached to the offset position 52d near the end 52a by the adhesive tape 55 instead of the pre-set position corresponding to the line segment 65, that is, the middle portion 52c, the curved shape of the film 52 does not match the height of the developer layer. Therefore, the film 52 does not contact the developer layer, and the toner is deposited higher than the magnetic attraction distribution 60 (see Figure 4 ) is high, becomes a block and falls on the developing roller 334 (refer to Figure 3 ) may cause image defects.

[0110] In this way, when the film 52 is pasted on the cover part 51, except for the end parts 52a and 52b, when the adhesive tape 55 is pasted at a position offset from the preset position, image defects may occur compared with the case where the adhesive tape 55 is pasted at the preset position, but the possibility of image defects is reduced compared with the case where the film 52 is not set.

[0111] The position of the middle portion 52 c of the film 52 on the cover member 51 when attached to the cover member 51 may be at the center of the cover member 51 in the circumferential direction S or may be offset from the center.

[0112] In addition, light contact in this specification means that the film 52 is in contact with the developer layer so that the film 52 does not affect the height of the developer layer of the developing roller 334 and a space for accumulating toner is not formed between the film 52 and the developer layer.

[0113] Figure 7 It is a perspective view showing the inner surface 51 b of the cover member 51 .

[0114] like Figure 7 As shown, an adhesive tape 55 for indication is provided on the inner surface 51b of the cover member 51 (see Figure 5 ) The middle portion 52c of the adhesive film 52 (see Figure 5 )’s position is indicated by a linear mark 51c.

[0115] The mark 51c is formed to extend in the longitudinal direction n of the cover member 51. Thus, the workability when attaching the film 52 to the cover member 51 is improved.

[0116] The longitudinal direction n is the same direction as the axial direction of the developing roller 334. The mark 51c is an example of a mark indicating the position of the middle position of the bonding film.

[0117] In addition, a mark 51e corresponding to the position of the axial end 51d of the developing roller 334 in the axial direction of the cover member 51 is formed on the inner surface 51b of the cover member 51. The magnetic poles 64a and 65a are not provided at the position closer to the end side than the mark 51e (for example, see Figure 4 ). Therefore, the above-mentioned mark 51c is not formed at a position closer to the end side than the mark 51e. Thus, the pasting workability is improved.

[0118] The axial end portion 51d is an example of a region of the covering member corresponding to an end portion of the developer holding member.

[0119] <Note> (((1)))

[0121] A developer, comprising:

[0122] a developer holding body for holding a developer containing a toner and a carrier, that is, the developer supplied to an image holding body for forming an electrostatic latent image;

[0123] a covering member that covers a portion of the developer holding body; and

[0124] A film is mounted on the covering member at an end portion of the developer holding member in the circumferential direction and in contact with the developer held by the developer holding member, and is also mounted on the covering member at a middle position in the circumferential direction. (((2)))

[0126] The developer according to (((1))) is characterized in that:

[0127] The middle position on the film is set based on the height of the developer layer attracted by the developer attracting magnet of the developer holding member. (((3)))

[0129] The developer according to (((2))) is characterized in that:

[0130] The intermediate position based on the setting includes a position corresponding to the position of the attracting magnet where the height of the developer layer is high. (((4)))

[0132] The developer according to (((3))) is characterized in that:

[0133] The intermediate position based on the setting does not include a position between the attracting magnets where the height of the developer layer is lower than the position of the attracting magnet. (((5)))

[0135] The developer according to (((1))) or (((2))), characterized in that:

[0136] The film mounted on the covering member is curved in a shape following a change in the height of the layer of the developer throughout the circumferential direction of the developer holding body. (((6)))

[0138] The developer according to any one of (((1))) to (((5))), characterized in that:

[0139] The middle position of the film is a central position of the film in the circumferential direction, and the film is attached to the central position of the cover member in the circumferential direction. (((7)))

[0141] The developer according to any one of (((1))) to (((6))), characterized in that:

[0142] The covering member has a mark indicating a position of the middle position where the film is attached on a surface facing the developer holding member. (((8)))

[0144] The developer according to (((7))) is characterized in that:

[0145] The mark is a linear mark extending along the longitudinal direction of the covering member. (((9)))

[0147] The developer according to (((8))) is characterized in that:

[0148] The linear mark is not formed in a region of the covering member corresponding to an end portion of the developer holding member where the developer attracting magnet of the developer holding member is not provided. (((10)))

[0150] An image forming device, comprising:

[0151] An image holding body, the image holding body forming an electrostatic latent image;

[0152] a developing unit that develops the electrostatic latent image formed on the image holding body into a toner image;

[0153] a transfer unit that transfers the toner image of the developing unit onto a recording material; and

[0154] a fixing unit that fixes the toner image transferred onto the recording material onto the recording material,

[0155] The developing unit comprises:

[0156] a developer holding body for holding a developer containing a toner and a carrier, that is, the developer supplied to an image holding body for forming an electrostatic latent image;

[0157] a covering member that covers a portion of the developer holding body; and

[0158] A film is mounted on the covering member at an end portion of the developer holding member in the circumferential direction and in contact with the developer held by the developer holding member, and is also mounted on the covering member at a middle position in the circumferential direction.

[0159] According to (((1))), a situation in which it is difficult to maintain the contact state between the film and the developer layer of the developer holding member does not occur, and the occurrence of toner accumulation can be suppressed compared to a case in which this structure is not adopted.

[0160] According to (((2))), the position of the middle of the film is set based on the height of the developer layer adsorbed by the developer adsorbing magnet possessed by the developer retaining body, and the occurrence of colorant accumulation can be suppressed compared to a case without this structure.

[0161] According to (((3))), since the set intermediate position includes the position corresponding to the position of the attraction magnet where the height of the developer layer is high, the occurrence of toner accumulation can be suppressed compared to a case where this structure is not provided.

[0162] According to (((4))), based on the set intermediate position, the position between the attraction magnets where the height of the layer not including the developer is lower than the position of the attraction magnet can suppress the occurrence of colorant accumulation compared to a case where this structure is not provided.

[0163] According to (((5))), the film attached to the covering member is curved in a shape following the change in height of the developer layer in the circumferential direction of the developer holding member, and the occurrence of toner accumulation can be suppressed compared to a case without this structure.

[0164] According to (((6))), the film whose middle position is the circumferential center of the film is installed at the circumferential center of the covering member, which is applicable regardless of the rotation direction of the developer retaining body, compared with the case without this structure.

[0165] According to (((7))), the covering member has a mark indicating the position of the middle position where the film is pasted on the surface facing the developer holding body, which can improve assembly workability compared to a case where this structure is not provided.

[0166] According to (((8))), the mark is a linear mark extending in the longitudinal direction of the covering member, and the assembly workability can be improved compared to a case where this structure is not provided.

[0167] According to (((9))), no linear mark is formed in the area of ​​the covering part corresponding to the end of the developer retaining body where the developer adsorbing magnet possessed by the developer retaining body is not provided, thereby improving the assembly workability compared to the case where this structure is not provided.

[0168] According to (((10))), a situation in which it is difficult to maintain the contact state between the film and the developer layer of the developer holding member is not formed, and the occurrence of toner accumulation can be suppressed compared to a case where this structure is not adopted.

Claims

1. A developer, characterized in that: have: a developer holding body for holding a developer containing a toner and a carrier, that is, the developer supplied to an image holding body for forming an electrostatic latent image; a covering member covering a portion of the developer holding body; as well as A film is mounted on the covering member at an end portion of the developer holding member in the circumferential direction and in contact with the developer held by the developer holding member, and is also mounted on the covering member at a middle position in the circumferential direction.

2. The developer according to claim 1, wherein: The middle position on the film is set based on the height of the developer layer attracted by the developer attracting magnet of the developer holding member.

3. The developer according to claim 2, wherein: The intermediate position based on the setting includes a position corresponding to the position of the attracting magnet where the height of the developer layer is high.

4. The developer according to claim 3, wherein: The intermediate position based on the setting does not include a position between the attracting magnets where the height of the developer layer is lower than the position of the attracting magnet.

5. The developer according to claim 1 or 2, wherein: The film mounted on the covering member is curved in a shape following a change in the height of the layer of the developer throughout the circumferential direction of the developer holding body.

6. The developer according to any one of claims 1 to 5, wherein: The middle position of the film is a central position of the film in the circumferential direction, and the film is attached to the central position of the cover member in the circumferential direction.

7. The developer according to any one of claims 1 to 6, wherein: The covering member has a mark indicating a position of the middle position where the film is attached on a surface facing the developer holding member.

8. The developer according to claim 7, wherein: The mark is a linear mark extending along the longitudinal direction of the covering member.

9. The developer according to claim 8, wherein: The linear mark is not formed in a region of the covering member corresponding to an end portion of the developer holding member where the developer attracting magnet of the developer holding member is not provided.

10. An image forming device, characterized in that: include: An image holding body, the image holding body forming an electrostatic latent image; a developing unit that develops the electrostatic latent image formed on the image holding body into a toner image; a transfer unit that transfers the toner image of the developing unit onto a recording material; as well as a fixing unit that fixes the toner image transferred onto the recording material onto the recording material, The developing unit comprises: a developer holding body for holding a developer containing a toner and a carrier, that is, the developer supplied to an image holding body for forming an electrostatic latent image; a covering member covering a portion of the developer holding body; as well as A film is mounted on the covering member at an end portion of the developer holding member in the circumferential direction and in contact with the developer held by the developer holding member, and is also mounted on the covering member at a middle position in the circumferential direction.

Images