JP2019135531A - Developer regulation member, developing device, and image forming apparatus - Google Patents

Abstract

To provide a developer regulation member that can prevent the occurrence of unevenness in density of an image when a magnetic member is fixed to a non-magnetic member and used for a developing device.SOLUTION: A development doctor 12 has a magnetic plate 121 being a plate-like magnetic member fixed to a holding member 122 being a non-magnetic member and is arranged opposite to the surface of a developer carrier. The holding member 122 is in contact with the magnetic plate 121 from both sides in a plate thickness direction of the magnetic plate 121, and the magnetic plate 121 does not have a through hole in the longitudinal direction within an image area α that is a range facing a range on the surface of the developer carrier where development is performed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a developer regulating member, a developing device, and an image forming apparatus.

2. Description of the Related Art Conventionally, there has been known a developer regulating member that is configured to have a plate-like magnetic member fixed to a non-magnetic member and to be opposed to the surface of a developer carrier.
As this kind of developer regulating member, Patent Document 1 discloses that the magnetic member has through holes at a plurality of positions in the longitudinal direction, and the convex portions provided on the non-magnetic member are passed through the through holes to be non-magnetic. The structure which fixes a magnetic member to a member is described.

  However, as described in Patent Document 1, when a developing device is used to perform development using a developer regulating member that fixes a magnetic plate to a nonmagnetic member by caulking to form an image, the position in the width direction of the formed image Depending on the density, uneven density may occur.

  In order to solve the above-described problems, the present invention provides a non-magnetic member in which the plate-like magnetic member is fixed and the non-magnetic member in the developer-regulating member disposed facing the surface of the developer carrier. The member comes into contact with the magnetic member from both sides in the plate thickness direction of the magnetic member, and the magnetic member has a through hole in a range opposite to a range in which the surface of the developer carrying member is developed in the longitudinal direction. It is characterized by not.

  According to the present invention, there is an excellent effect that it is possible to suppress the occurrence of density unevenness of an image when a magnetic member is fixed to a nonmagnetic member and used in a developing device.

FIG. 3 is an explanatory diagram of a developing doctor according to the first embodiment. 1 is a schematic configuration diagram of a copier according to an embodiment. 1 is a schematic configuration diagram of a process cartridge according to an embodiment. FIG. 3 is a perspective cross-sectional view of the developing device according to the embodiment. FIG. 3 is an enlarged schematic cross-sectional view of the periphery of the developing doctor of the developing device according to the embodiment. FIG. 10 is a schematic cross-sectional view of a developing doctor of Modification 1; FIG. 10 is a schematic cross-sectional view of a developing doctor according to a second modification. FIG. 10 is a schematic cross-sectional view of a developing doctor according to Modification 3. FIG. 6 is an explanatory diagram of a developing doctor according to a second embodiment. FIG. 10 is a schematic cross-sectional view of a developing doctor of Modification 4 and Modification 5. FIG. 6 is an explanatory diagram of a developing doctor according to a third embodiment. Explanatory drawing of the developing doctor of the modification 6. FIG. Explanatory drawing which shows an example of the conventional developing doctor.

Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment (hereinafter simply referred to as “embodiment”) of a tandem type color laser copying machine (hereinafter simply referred to as “copying machine”) in which a plurality of photoconductors are arranged in parallel. ").
FIG. 2 is a schematic configuration diagram of a copier 500 according to the embodiment. The copier 500 includes a printer unit 100, a paper feeding device 200 on which the printer unit 100 is placed, a scanner 300 fixed on the printer unit 100, and the like. An automatic document feeder 400 fixed on the scanner 300 is also provided.

  The printer unit 100 is an image composed of four process cartridges 18 (Y, M, C, K) for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). A forming unit 20 is provided. Y, M, C, and K added after the numerals in FIG. 2 indicate members for yellow, cyan, magenta, and black. Each of the four process cartridges 18 is substantially the same except that the color of the toner to be used is different. Therefore, in the following description, subscripts for color classification (Y, M, C, K) are omitted as appropriate. explain.

  In addition to the four process cartridges 18, the printer unit 100 includes an optical writing unit 21, an intermediate transfer unit 17, a secondary transfer device 22, a registration roller pair 49, a belt fixing type fixing device 25, and the like. Yes. The optical writing unit 21 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of the photoreceptor 1 described later with laser light based on image data.

Next, the configuration and operation of the process cartridge 18 will be described.
The process cartridge 18 is mounted on the copying machine 500 main body by being inserted into the mounting space in the copying machine 500 main body from the front side to the back side in FIG.
FIG. 3 is a schematic configuration diagram of the process cartridge 18. The process cartridge 18 includes a drum-shaped photoconductor 1, a drum cleaning unit 72 disposed around the photoconductor 1, a charging unit 71, and a developing device 4.

  The drum cleaning unit 72 includes a cleaning blade 72a, which is an elastic member elongated in the direction of the rotation axis of the photoreceptor 1, and a discharge screw 72b. One side (contact side) extending in the longitudinal direction of the cleaning blade 72a is pressed against the surface of the photoreceptor 1 as an edge portion, and unnecessary deposits such as transfer residual toner on the surface of the photoreceptor 1 are separated and removed. The removed toner is discharged out of the drum cleaning unit 72 by the discharge screw 72b. The drum cleaning unit 72 is provided with a charge removal member 72c to which a DC voltage is applied. The charging unit 71 includes a charging roller 71a disposed so as to contact the photoreceptor 1, and a charging roller cleaner 71b that rotates while contacting the charging roller 71a.

  The surface of the photoreceptor 1 is uniformly charged by a charging unit 71 that is a charging unit. The surface of the photoreceptor 1 subjected to the charging process is irradiated with laser light modulated and deflected by the optical writing unit 21. Then, the potential of the irradiation part (exposure part) is attenuated. By this attenuation, an electrostatic latent image is formed on the surface of the photoreceptor 1. The formed electrostatic latent image is developed into a toner image by the developing device 4 as developing means. The toner image formed on the photoreceptor 1 is primarily transferred to an intermediate transfer belt 110 described later. The surface of the photoreceptor 1 after the primary transfer is cleaned of the transfer residual toner by the cleaning blade 72a of the drum cleaning unit 72. The cleaned photoreceptor 1 is neutralized by the neutralizing member 72c. Then, it is uniformly charged by the charging unit 71 and returns to the initial state.

  The series of processes as described above are the same for the process cartridges 18 (Y, M, C, K).

  Next, the intermediate transfer unit 17 will be described with reference to FIG. The intermediate transfer unit 17 includes an intermediate transfer belt 110 and a belt cleaning device 19. Further, the tension roller 14, the belt driving roller 15, the secondary transfer backup roller 16, and four primary transfer rollers 73 (Y, M, C, K) are also provided. The intermediate transfer belt 110 is tensioned by a plurality of rollers including the tension roller 14. Then, the belt drive roller 15 driven by the belt drive motor rotates endlessly in the clockwise direction in FIG.

  The four primary transfer rollers 73 (Y, M, C, K) are disposed so as to be in contact with the inner peripheral surface side of the intermediate transfer belt 110, respectively, and receive a primary transfer bias from a power source. Further, the intermediate transfer belt 110 is pressed from the inner peripheral surface thereof toward the photoreceptor 1 (Y, M, C, K) to form primary transfer nips. In each primary transfer nip, a primary transfer electric field is formed between the photoreceptor 1 and the primary transfer roller 73 due to the influence of the primary transfer bias.

  The yellow toner image formed on the yellow photoconductor 1Y is primarily transferred onto the intermediate transfer belt 110 due to the influence of the primary transfer electric field and nip pressure. On the yellow toner image, the magenta toner image, the cyan toner image, and the black toner image formed on the magenta, cyan, and black photoreceptors 1 (M, C, and K) are sequentially superimposed and sequentially transferred. The By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image), which is a multiple toner image, is formed on the intermediate transfer belt 110. The four-color toner image formed on the intermediate transfer belt 110 is secondarily transferred onto a transfer sheet as a recording medium at a secondary transfer nip described later. The transfer residual toner remaining on the surface of the intermediate transfer belt 110 after passing through the secondary transfer nip is cleaned by a belt cleaning device 19 that sandwiches the belt with the belt drive roller 15 on the left side in FIG.

  Next, the secondary transfer device 22 will be described. Below the intermediate transfer unit 17 in FIG. 2, a secondary transfer device 22 is provided in which a paper transport belt 24 is stretched by two transport stretch rollers 23. The paper transport belt 24 moves endlessly in the counterclockwise direction in the drawing in accordance with the rotational drive of at least one of the transport stretch rollers 23. One of the two conveying stretch rollers 23 disposed on the right side in FIG. 2 is interposed between the intermediate transfer belt 110 and the secondary transfer backup roller 16 of the intermediate transfer unit 17. In addition, the paper conveying belt 24 is sandwiched. By this sandwiching, a secondary transfer nip is formed in which the intermediate transfer belt 110 of the intermediate transfer unit 17 and the paper transport belt 24 of the secondary transfer device 22 are in contact with each other. A secondary transfer bias having a polarity opposite to that of the toner is applied to the one conveying stretch roller 23 by a power source. By applying this secondary transfer bias, the four-color toner image on the intermediate transfer belt 110 of the intermediate transfer unit 17 is electrostatically moved from the belt side toward the one conveying stretch roller 23 side in the secondary transfer nip. A secondary transfer electric field is formed. The transfer paper fed into the secondary transfer nip so as to synchronize with the four-color toner image on the intermediate transfer belt 110 by a registration roller pair 49 described later has four colors affected by the secondary transfer electric field and nip pressure. The toner image is secondarily transferred.

  In the paper feeding device 200 provided at the lower part of the copying machine 500 main body, a plurality of paper feeding cassettes 44 in which a plurality of transfer sheets can be stacked and stored in a bundle of sheets are arranged so as to overlap each other in the vertical direction. It is installed. Each paper feed cassette 44 presses the paper feed roller 42 against the uppermost transfer paper in the paper bundle. By rotating the paper feed roller 42, the uppermost transfer paper is sent out toward the paper feed path 46. The paper feed path 46 that receives the transfer paper fed from the paper feed cassette 44 has a plurality of conveying roller pairs 47 and a registration roller pair 49 provided near the end in the path. In the paper feed path 46, the transfer sheet is conveyed toward the registration roller pair 49, and the transfer sheet conveyed toward the registration roller pair 49 is sandwiched between the rollers of the registration roller pair 49.

  On the other hand, in the intermediate transfer unit 17, the four-color toner image formed on the intermediate transfer belt 110 enters the secondary transfer nip as the belt moves endlessly. The registration roller pair 49 sends out the transfer paper sandwiched between the rollers at a timing at which the transfer paper can be brought into close contact with the four-color toner image at the secondary transfer nip. As a result, at the secondary transfer nip, the four-color toner image on the intermediate transfer belt 110 is in close contact with the transfer paper. Then, it is secondarily transferred onto the transfer paper and becomes a full color image on the white transfer paper. The transfer paper on which the full-color image is formed in this manner exits the secondary transfer nip as the paper transport belt 24 moves endlessly, and is transported to the paper transport belt 24 and sent to the fixing device 25.

  The fixing device 25 includes a fixing belt 26 that is stretched by two rollers and moves endlessly, and a pressure roller 27 that is pressed toward one roller of the fixing belt 26. The fixing belt 26 and the pressure roller 27 come into contact with each other to form a fixing nip. Of the two rollers of the fixing belt 26, the roller that is pressed by the pressure roller 27 has a heat source inside, and heats the fixing belt 26 by the heat generated by the heat source. The heated fixing belt 26 heats the transfer paper sandwiched in the fixing nip. The full color image is fixed on the transfer paper by the influence of the heating and the nip pressure. The transfer paper subjected to the fixing process in the fixing device 25 is discharged and stacked by the discharge roller pair 64 on the stack portion 65 provided outside the left side plate in FIG. . Alternatively, the toner image is returned to the above-described secondary transfer nip in order to form a toner image on the other surface.

When a document is copied, if the document is in a sheet form, a bundle of documents is set on the document table 30 of the automatic document feeder 400, and the document is a single-stitched document that is closed in a main form. In some cases, it is set on the contact glass 32. When setting on the contact glass 32, the automatic document feeder 400 is opened with respect to the copying machine 500, and the contact glass 32 of the scanner 300 is exposed. Thereafter, the single-bound original is pressed by the closed automatic document feeder 400.
When the copy start switch is pressed after the document is set in this way, the document reading operation by the scanner 300 starts. However, when a sheet-like document is set on the automatic document feeder 400, the automatic document feeder 400 automatically moves the sheet-like document to the contact glass 32 prior to this document reading operation.

  In the document reading operation, first, the first traveling body 33 and the second traveling body 34 both start traveling, and light is emitted from a light source provided in the first traveling body 33. Then, the reflected light from the document surface is reflected by a mirror provided in the second traveling body 34, passes through the imaging lens 35, and then enters the reading sensor 36. The reading sensor 36 constructs image information based on the incident light. In parallel with such document reading operation, each device in the four process cartridges 18 (Y, M, C, K), the intermediate transfer unit 17, the secondary transfer device 22, and the fixing device 25 start driving. To do. Then, based on the image information constructed by the reading sensor 36, the optical writing unit 21 is driven and controlled, and yellow, magenta are formed on the respective surfaces of the four photosensitive members 1 (Y, M, C, K). , Cyan and black toner images are formed. These toner images are superimposed and transferred onto the intermediate transfer belt 110 to form the above-described four-color toner image.

  Almost simultaneously with the start of the document reading operation, the paper feeding operation is started in the paper feeding device 200. In this paper feed operation, one of the paper feed rollers 42 is selectively rotated, and the transfer paper is sent out from one of the paper feed cassettes 44 accommodated in the paper bank 43 in multiple stages. The fed transfer paper is separated one by one by the separation roller 45 and enters the paper feed path 46, and is then transported toward the secondary transfer nip by the transport roller pair 47. In some cases, paper is fed from the manual feed tray 61 instead of such paper feeding from the paper feeding cassette 44. In this case, after the manual feed roller 60 is selectively rotated and the transfer paper on the manual feed tray 61 is sent out, the manual separation roller 62 separates the transfer paper one by one and feeds it to the manual feed path 63 of the printer unit 100. Make paper.

  In the case of forming a multi-color image composed of two or more colors of toner, the copying machine stretches the intermediate transfer belt 110 so that the upper stretched surface is almost horizontal, The photosensitive member 1 (Y, M, C, K) is brought into contact. On the other hand, when forming a monochrome image consisting only of black toner, the intermediate transfer belt 110 is inclined to the lower left in FIG. 2, and the upper stretched surface is exposed to yellow, magenta, and cyan. Separated from the body 1 (Y, M, C). Then, among the four photosensitive members 1 (Y, M, C, K), only the black photosensitive member 1K is rotated counterclockwise in FIG. 2 to form only the black toner image. At this time, for the process cartridges 18 (Y, M, C) for yellow, magenta, and cyan, not only the photoreceptor 1 (Y, M, C) but also the developing device 4 (Y, M, C) are driven. By stopping, unnecessary consumption of the photoreceptor 1 and the developer is prevented.

Next, the developing device 4 will be described with reference to FIGS. 3 and 4.
FIG. 4 is a perspective sectional view of the developing device 4 according to the embodiment. The developing device 4 supplies toner to the latent image on the surface of the photoreceptor 1 while moving in the direction of the arrow “I” in FIG. 3, and stores the developing roller 5 as a developer carrying member for developing the developer. And a developing case 40 which is a developer containing portion. As shown in FIGS. 3 and 4, a heat radiating portion 120 is formed on the side surface of the developing case 40.
The developing device 4 of the present embodiment employs a two-component developing system that uses a two-component developer composed of toner and carrier. As a developing device to which the present invention is applied, a one-component developing system using a magnetic one-component developer may be adopted as long as the developer is supported on a developer carrier such as the developing roller 5 by magnetic force. .

The developing roller 5 includes a magnet roller 5b composed of a plurality of magnets fixed inside, and a developing sleeve 5a composed of an aluminum sleeve that encloses the magnet roller 5b and rotates around the magnet roller 5b. As the developing sleeve 5a rotates around the magnet roller 5b forming a plurality of magnetic poles, the developer moves on the developing roller 5 with the rotation.
The developing roller 5 develops the latent image on the surface of the photoconductor 1 in the developing area A including the closest portion to the photoconductor 1.

  A developing electric field is formed between the developing sleeve 5 a and the photosensitive member 1 in the developing region A by applying a developing bias to the developing sleeve 5 a of the developing roller 5 from a power source that is a developing bias applying unit. By this developing electric field, in the developing area A, the toner in the developer on the surface of the developing sleeve 5a is supplied to the latent image on the surface of the photoreceptor 1, and the latent image on the photoreceptor 1 is developed.

  Development that regulates the developer supplied to the developing roller 5 and conveyed by the surface movement to a thickness suitable for development on the downstream side of the surface moving direction from the portion facing the supply screw 8 around the developing roller 5 A developing doctor 12 is provided as an agent regulating member. The developing case 40 has a first partition wall 133 and a second partition wall 134, and the interior of the developing case 40 is separated from the supply conveyance path 9 and the collection by the first partition wall 133 and the second partition wall 134. The conveyance path 7 and the agitation conveyance path 10 are partitioned.

  A supply screw 8 serving as a supply / conveying member that conveys the developer to the front side of the paper in FIG. 3 while supplying the developer to the developing roller 5 is disposed in the supply / conveyance path 9 that is a developer supply unit. The supply screw 8 is a developer conveying screw that includes a rotating shaft and a blade portion provided on the rotating shaft and conveys the developer in the axial direction by rotating.

  A collection conveyance path 7 is provided at a position facing the surface of the developing roller 5 on the downstream side of the developing area A in the surface movement direction of the developing roller 5. The developed developer carried on the surface of the developing roller 5 and having passed through the developing area A falls through the collection port B to the collection conveyance path 7 which is a developer collection unit and is collected. The collection conveyance path 7 which is a developer collection unit includes a collection screw 6 as a collection conveyance member that conveys the collected recovery developer in the same direction as the supply screw 8. A supply conveyance path 9 provided with the supply screw 8 is arranged in the lateral direction of the developing roller 5, and a collection conveyance path 7 provided with the collection screw 6 is arranged in parallel below the development roller 5.

  The agitation conveyance path 10 that is an agitation conveyance unit is provided in parallel with the recovery conveyance path 7 below the supply conveyance path 9. The agitating and conveying path 10 includes an agitating screw 11 as an agitating and conveying member that conveys the developer to the back side of the paper surface in FIG. The supply conveyance path 9 and the agitation conveyance path 10 are partitioned by a first partition wall 133. As for the part which divides the supply conveyance path 9 and the agitation conveyance path 10 of the first partition wall 133, both ends of the front side and the back side of the paper surface in FIG. 3 are openings, and the supply conveyance path 9 and the agitation conveyance path 10 Are communicating.

  The supply conveyance path 9 and the recovery conveyance path 7 are also partitioned by the first partition wall 133, but no opening is provided at a location where the supply conveyance path 9 and the recovery conveyance path 7 of the first partition wall 133 are partitioned. The agitation conveyance path 10 and the collection conveyance path 7 are partitioned by a second partition wall 134. The downstream end of the second partition wall 134 in the developer conveyance direction by the collection screw 6 is an opening, and the stirring conveyance path 10 and the collection conveyance path 7 communicate with each other.

  The developing device 4 has a developer discharge port 9 a that discharges a part of the developer in the supply conveyance path 9 to the outside of the developing device 4 when the developer exceeds a predetermined volume. Further, it also has a discharge conveyance path 2 including a discharge conveyance screw 2 a for conveying the developer discharged from the developer discharge port 9 a to the outside of the developing device 4. The discharge conveyance path 2 is arranged on the downstream side in the conveyance direction of the supply conveyance path 9 so as to be adjacent to the supply conveyance path 9 with the third partition wall 135 interposed therebetween, and the developer discharge port 9a is connected to the supply conveyance path 9 and the discharge conveyance path. 2 is an opening provided in the third partition wall 135 so as to communicate with the second partition wall 135.

  The developer in the developing device 4 is held by the developing case 40 and is supplied to the developing roller 5 while being conveyed by the supply screw 8. Then, an appropriate amount of developer held by the magnet roller 5b arranged in a fixed state inside the developing roller 5 and regulated by the developing doctor 12 is conveyed to the developing region A by the rotating developing sleeve 5a, and The toner is supplied to the latent image and developed. The developer that has been developed is accommodated again in the developing device 4 via the recovery port B, stirred and transported in the recovery transport path 7 by the recovery screw 6, and stirred at the downstream end of the recovery transport path 7 in the transport direction. 11 is delivered to the stirring and conveying path 10 in which 11 is disposed. New toner is supplied into the developing device 4 through the path between the delivery, and the developer and new toner delivered from the collection transport path 7 are transported while being stirred by the stirring screw 11. Then, the developer that has been stirred and transported is delivered to the supply transport path 9 at the downstream end of the stirring transport path 10 in the transport direction.

FIG. 5 is an enlarged schematic cross-sectional view of the periphery of the developing doctor 12 of the developing device 4 of the present embodiment.
As shown in FIG. 5, the developing doctor 12 includes a magnetic plate 121 made of a plate-like magnetic body and a holding member 122, and the leading end surface of the magnetic plate 121 and the leading end surface of the holding member 122 are opposed to the developing sleeve 5a. To do.
Further, the developing doctor 12 has a longitudinal direction in the width direction (direction perpendicular to the paper surface of FIG. 3) perpendicular to the moving direction on the surface of the developing roller 5 which is a developer carrying member that carries the developer by magnetic force. It is arranged to face the surface of the developing roller 5.
The magnetic plate 121 is close to the surface of the developing sleeve 5a and forms a doctor gap D between the magnetic plate 121 and the developing sleeve 5a. The developing device 4 regulates the amount of the developer carried on the developing sleeve 5a by the doctor gap D and supplied to the developing area A.

The holding member 122 holds the magnetic plate 121. The magnetic plate 121 can be fixed to the developing case 40 by fixing the holding member 122 to the developing case 40 by fixing means such as screw fastening. The holding member 122 may be formed separately from the developing case 40 and assembled to the developing case 40, or a part or all of the holding member 122 may be formed integrally with the developing case 40. As a fixing method for fixing the holding member 122 that holds the magnetic plate 121 to the developing case 40, a known fixing method such as screw fastening, caulking, or adhesion using an adhesive can be used.
Hereinafter, two surfaces orthogonal to the plate thickness direction of plate-like members such as the magnetic plate 121 and the holding member 122 are referred to as “plate surfaces”.

The magnetic plate 121 of the developing doctor 12 of this embodiment is a magnetic metal plate having a thickness of 1.0 [mm] or less.
If the developer is regulated using a metal plate having a thickness exceeding 1.0 [mm], the closest position between the surface of the developer carrying member and the developing doctor 12 may vary within the thickness range of the tip surface of the metal plate. There is. In order to suppress this variation, if the front end surface of the metal plate is obliquely cut and inclined, it takes time and effort to make the oblique cutting process, and the component cost increases.
Also, if the plate thickness is thick, a sag surface between the tip surface and the plate surface can be formed when the plate shape is extracted with a press. When the developer is regulated using a metal plate with a sag surface, the developer accumulates on the sag surface, and the tip of the accumulated developer aggregate is closer to the surface of the developer carrier than the tip surface of the plate member. When the agglomerates grow to the point, defects such as white streaks occur.

Since the magnetic plate 121 of the embodiment is thin with a thickness of 1.0 [mm] or less, it is possible to suppress variation in the closest position in the range of the thickness of the tip surface, and to cut and tilt the tip surface obliquely. Can be eliminated, and the cost of parts can be reduced.
In addition, by using a thin plate member, when the plate shape is extracted with a press, the sag surface cannot be formed, or even if a sag surface is formed, the width is narrow and developer accumulation is difficult to occur. It is possible to prevent the occurrence of problems caused by the accumulation of

When a thin plate having a thickness of 1.0 [mm] or less is used as the magnetic plate 121 forming the doctor gap D with the developing sleeve 5a, the magnetic plate 121 pressed by the developer when the developer is restricted. There is a possibility that the size of the doctor gap D may fluctuate due to bending of the doctor gap D. In the present embodiment, a magnetic plate 121 that is a thin plate member is held by a holding member 122 that is a rigid member made of a nonmagnetic metal or resin, and the front surface side of the magnetic plate 121 facing the developing sleeve 5a (in FIG. 5). A part of the lower side protrudes from the holding member 122. By holding the high-rigidity holding member 122 except for the protruding part of the magnetic plate 121, the bending of the magnetic plate 121 can be suppressed.
In the present embodiment, the protruding amount of the magnetic plate 121 with respect to the holding member 122 is set to 0.4 [mm], but is not limited thereto.

  In the developing doctor 12 of the developing device 4 illustrated in FIG. 5, the holding member 122 is configured by a rigid member including one component, but the holding member 122 may be a rigid member including a plurality of components.

  When the magnetic plate 121 is thick, depending on the installation angle of the magnetic plate 121 with respect to the tangent line of the developing sleeve 5a at the closest position, the front end surface of the magnetic plate 121 and the developing sleeve may be upstream of the surface moving direction of the developing sleeve 5a at the closest position. A wedge-shaped space is formed by the surface of 5a. When such a wedge-shaped space is formed, the developer that is blocked by the magnetic plate 121 and cannot pass through the doctor gap D accumulates in the wedge-shaped space, and the deposited developer blocks the doctor gap D. There is a risk that the amount of the developer supplied to the development area A is reduced.

In this embodiment, since the magnetic plate 121 is thin, the width of the front end surface of the magnetic plate 121 forming the wedge-shaped space is narrow, and the developer is difficult to deposit. Further, since the magnetic plate 121 is thin, the developer can be sheared in a state close to a point regardless of the angle of the developing doctor 12 with respect to the tangent at the closest position of the developing sleeve 5a. Therefore, it is possible to prevent the developer from being deposited on the upstream side of the developer regulating member at low cost without secondary processing such as tilting the front end surface of the magnetic plate 121.
In this embodiment, the developer blocked by the magnetic plate 121 can be prevented from causing problems due to accumulation on the upstream side of the closest position, and the magnetic plate with respect to the tangent of the developing sleeve 5a at the closest position. The degree of freedom of the installation angle of 121 is improved.

Here, an example of a conventional developer regulating member will be described.
FIG. 13 is an explanatory view showing an example of a conventional developing doctor 12. FIG. 13A is a schematic cross-sectional view of a cross section orthogonal to the longitudinal direction of the developing doctor 12 (direction parallel to the rotation axis of the developing sleeve 5a in the developing device 4). FIG. 13B is a schematic view of the developing doctor 12 as viewed from the left side in FIG. 13A. The position of the crimping in the longitudinal direction of the developing doctor 12 and the variation in the amount of developer passing through the doctor gap D are shown in FIG. It is explanatory drawing which shows these relationships. Fig.13 (a) is sectional drawing in the EE cross section in FIG.13 (b).

The developing doctor 12 shown in FIG. 13 holds the convex portion 122a by caulking the convex portion 122a after passing the convex portion 122a formed on one of the plate surfaces of the plate-like holding member 122 through the hole portion 121a provided in the magnetic plate 121. A magnetic plate 121 is fixed to the member 122.
As shown in FIG. 13B, the magnetic plate 121 is provided with a plurality of holes 121a in the longitudinal direction. After passing the convex portion 122a of the holding member 122 through each of the plurality of hole portions 121a, the tip of the convex portion 122a is heated and softened, and the outer diameter on the tip side of the convex portion 122a is larger than the inner diameter of the hole portion 121a. Crush the tip so that it becomes. By caulking the convex portion 122a, the magnetic plate 121 is sandwiched between the crushed portion of the tip of the convex portion 122a and the plate surface of the holding member 122, and the holding member 122 and the magnetic plate 121 are brought into close contact with each other. It can be moved not only in the direction but also in the surface direction. Thus, by fixing by caulking, the position of the magnetic plate 121 with respect to the holding member 122 in the plate thickness direction is fixed, and the direction orthogonal to the plate thickness direction (hereinafter referred to as “surface direction”) is also fixed. be able to.

However, as shown in FIG. 13, in the configuration in which a plurality of holes 121a are provided along the longitudinal direction of the magnetic plate 121, the amount of developer passing through the doctor gap D varies depending on the position in the width direction of the developing sleeve 5a. There was a thing. The graph “T” in FIG. 13B shows the outline of the variation in the developer amount, and the amount of developer passing through the portion where the position in the longitudinal direction coincides with the hole 121a is large.
This is thought to be due to the following reasons.

  That is, by providing the magnetic plate 121 on the developing doctor 12 that forms the doctor gap D, a strong magnetic field is formed in and around the doctor gap D by the magnetic plate 121 and the magnet roller 5b. At this time, the strength of the magnetic field varies depending on the amount of the magnetic material facing the magnet roller 5b with the developing sleeve 5a interposed therebetween. Since the amount of the magnetic material facing the magnet roller 5b differs depending on the presence or absence of the hole 121a in which the hole 121a is provided in the magnetic plate 121, the magnetic field strength is not uniform in the longitudinal direction (width direction) of the magnetic plate 121. It becomes. Specifically, in the longitudinal direction, the strength of the magnetic field is weakened in the portion where the hole 121a is provided because the amount of the magnetic material is smaller than in other portions.

On the surface of the developing sleeve 5a, the developer rises along the magnetic field lines of the magnetic field to form a magnetic brush. In this magnetic brush, the stronger the magnetic field, the larger the gap between the magnetic brushes, and the developer becomes Become sparse. For this reason, in the part provided with the hole 121a where the strength of the magnetic field becomes weaker, the developer becomes denser than the other part, and the amount of the developer passing through the doctor gap D increases.
When the amount of the developer passing through the doctor gap D varies depending on the position in the width direction of the developing sleeve 5a, the density of the image developed in the developing area A becomes uneven, and the image formed on the transfer paper is changed. Also, density unevenness occurs.

  In the developing doctor 12 of the developing device 4 of the present embodiment, as shown in FIG. 5, the holding member 122 that is a nonmagnetic member contacts the magnetic plate 121 from both sides in the plate thickness direction of the magnetic plate 121 that is a magnetic member. The magnetic plate 121 is held. Further, the magnetic plate 121 does not have a through hole in a range opposite to a range where the development of the surface of the developing roller 5 is performed in the longitudinal direction (the direction perpendicular to the paper surface of FIG. 5 and the width direction of the developing roller 5). It has a configuration. Since the magnetic plate 121 does not have a through hole in the above range, the developing device 4 can prevent a difference in developer carrying amount due to a difference in magnetic field strength. Thereby, in the range which develops, it can suppress that the carrying amount of a developer varies, and can suppress the generation of density unevenness in the developed image.

  Hereinafter, examples of the developing doctor 12 applicable to the developing device 4 of the present embodiment will be described.

[Example 1]
FIG. 1 is an explanatory diagram of a first embodiment of the developing doctor 12 (hereinafter referred to as “embodiment 1”). FIG. 1A is a schematic cross-sectional view of a cross section orthogonal to the longitudinal direction of the developing doctor 12 (direction parallel to the rotation axis of the developing sleeve 5a in the developing device 4). FIG. 1B is a schematic view of the developing doctor 12 as viewed from the left side in FIG. Fig.1 (a) is sectional drawing in the EE cross section in FIG.1 (b). An arrow “F” in FIG. 1A indicates the rotation direction of the developing sleeve 5 a facing the front end surface of the developing doctor 12. An area indicated by an arrow “α” in FIG. 1B is a range (hereinafter, referred to as “image area α”) facing a range where development in the width direction of the developing sleeve 5a in the longitudinal direction of the magnetic plate 121 is performed. Show.

The magnetic plate 121 of the developing doctor 12 of Example 1 shown in FIG. 1 does not have a through hole in the range of the image region α in the longitudinal direction (left and right direction in FIG. 1B). It has a uniform cross section in the shape shown in a).
In addition, the holding member 122 that is a nonmagnetic member is formed by integral molding so as to cover other than the lower portion of the magnetic plate 121. And as shown in FIG. 1, it is contacting both of the two surfaces orthogonal to the plate | board thickness direction of the magnetic board 121. As shown in FIG. Further, the magnetic plate 121 has a bent portion 121c bent in the right direction in FIG. 1A at the upper end portion of the main body portion 121b extending in the vertical direction at the upper end portion which is a range in contact with the holding member 122. .

  Since the magnetic plate 121 has no through-holes within the image area α and has a uniform cross section, it is possible to prevent variations in the strength of the magnetic field formed by the magnetic plate 121 and the magnet roller 5b, and the doctor gap D The amount of developer passing through can be kept constant. For this reason, it is possible to prevent density unevenness of the developed image developed on the surface of the photoreceptor 1 due to variations in the strength of the magnetic field, and to improve the image quality formed on the transfer paper.

The holding member 122 is in contact with both of the two plate surfaces of the magnetic plate 121. Thereby, it is possible to prevent the magnetic plate 121 from moving in the plate thickness direction that is parallel to the moving direction of the developing sleeve 5a at the position facing the magnetic plate 121 (the left-right direction in FIG. 1A).
Here, if the magnetic plate 121 is a flat plate-shaped member, the magnetic plate 121 may move in the surface direction, and the magnetic plate 121 may fall out of the holding member 122. In contrast, in the developing doctor 12 according to the first embodiment, since the magnetic plate 121 has the bent portion 121c, when the magnetic plate 121 tries to move in the surface direction with respect to the holding member 122, the bent portion 121c becomes the holding member 122. Stuck and inhibits movement. Thereby, the magnetic plate 121 can be prevented from falling off from the holding member 122, and the magnetic plate 121 can be fixed to the holding member 122.
As described above, the developing doctor 12 according to the first embodiment fixes the density unevenness of the developed image when used in the developing device 4 while fixing the magnetic plate 121 as the magnetic member to the holding member 122 as the nonmagnetic member. Occurrence can be suppressed.

  The magnetic plate 121 of Example 1 does not have a through hole in the image region α in the longitudinal direction, and has a bent portion 121c. The holding member 122 is made of a highly rigid resin material, and is formed by integral molding so as to be supported from both sides of the magnetic plate 121 in the plate thickness direction. By supporting the thin magnetic plate 121 from both sides by the highly rigid holding member 122, it is possible to prevent the magnetic plate 121 from being deformed by the pressure from the developer, and in the longitudinal direction while maintaining the rigidity of the developing doctor 12. The developer can be regulated uniformly.

  In addition, since the conventional magnetic plate 121 described with reference to FIG. 13 has through-holes extending in the entire longitudinal direction, the magnetic plate 121 may be deformed when processing to provide the through-holes is performed. . In addition, the magnetic plate 121 is joined to the holding member 122 by caulking at the position of the through hole. In the first embodiment, since no through hole is provided in the image area α, it is possible to prevent deformation of the range of the image area α of the magnetic plate 121 when performing the process of providing the through hole. Further, since the joining by caulking is not performed in the range of the image area α, it is possible to prevent the deformation in the range of the image area α of the magnetic plate 121 during the joining. Since it is possible to prevent deformation in the range of the image area α of the magnetic plate 121, the developer can be uniformly regulated by the magnetic plate 121.

[Modification 1]
FIG. 6 is a schematic cross-sectional view of a first modified example (hereinafter referred to as “modified example 1”) of the developing doctor 12 in which the magnetic plate 121 has a bent portion 121c.
The developing doctor 12 of Modification 1 has a configuration in which the upstream side and the downstream side in the surface movement direction of the developing sleeve 5a are inclined with respect to the portion where the magnetic plate 121 at the lower end of the holding member 122 protrudes.
By inclining the lower end portion of the holding member 122, it is possible to suppress a change in the developer speed when the developer is regulated by the magnetic plate 121, to suppress the deterioration of the developer, and to deteriorate the developer whose fluidity is deteriorated. It is possible to suppress a decrease in pumping amount due to stagnation.
Since the holding member 122 is the same as the first embodiment except that the holding member 122 is inclined, the first modification is used in the developing device 4 while securing the magnetic plate 121 to the holding member 122 as in the first embodiment. Occurrence of density unevenness of the developed image can be suppressed.

[Modification 2]
FIG. 7 is a schematic cross-sectional view of a second modified example (hereinafter, referred to as “modified example 2”) of the developing doctor 12 in which the magnetic plate 121 has a bent portion 121c.
The developing doctor 12 of Modification 2 includes an upstream holding member 122b in which the holding member 122 contacts the upstream plate surface of the magnetic plate 121 in the surface movement direction of the developing sleeve 5a, and a downstream plate surface of the magnetic plate 121. And a downstream holding member 122c in contact with. The developing doctor 12 shown in FIG. 7 includes holes at a plurality of positions in the longitudinal direction of the upstream holding member 122b (the direction orthogonal to the paper surface in FIG. 7), and the downstream holding member 122c corresponds to each of the upstream holding members 122b. A convex portion penetrating the hole portion is provided.

In the developing doctor 12 shown in FIG. 7, the downstream holding member 122 c that penetrates the hole of the upstream holding member 122 b in a state where the upstream holding member 122 b and the downstream holding member 122 c are in contact with the plate surface of the magnetic plate 121. Crush the tip of the convex part. Thereby, the holding member 122 contacts both of the two plate surfaces of the magnetic plate 121 to hold the magnetic plate 121.
Since the holding member 122 is the same as the first embodiment except that the holding member 122 is composed of two parts, the magnetic plate 121 is also fixed to the holding member 122 in the second modification, and the developing device 4 is used as in the first embodiment. Occurrence of density unevenness of the developed image can be suppressed.

  The material of the upstream side holding member 122b and the downstream side holding member 122c may be a nonmagnetic metal material or a nonmagnetic resin material. One may be a nonmagnetic metal material and the other may be a nonmagnetic resin material.

[Modification 3]
FIG. 8 is a schematic cross-sectional view of a third modified example (hereinafter referred to as “modified example 3”) of the developing doctor 12 in which the magnetic plate 121 has a bent portion 121c.
In the developing doctor 12 according to the first embodiment, the first modification, and the second modification, the magnetic plate 121 protrudes from the holding member 122 at the end on the developing sleeve 5a side, and the leading end surface of the magnetic plate 121 and the developing sleeve 5a. A doctor gap D is formed with the surface of On the other hand, as shown in FIG. 8, the developing doctor 12 of Modification 3 has the holding member 122 protruding from the magnetic plate 121 at the end on the developing sleeve 5 a side. In such a configuration, the doctor gap D is formed between the front end surface of the holding member 122 (“downstream holding member 122c” in the example of FIG. 8) and the surface of the developing sleeve 5a.

Even in the configuration in which the doctor gap D is formed by the holding member 122, if the amount of the magnetic plate 121 in the image region α in the width direction varies, the amount of the developer passing through the doctor gap D is the position in the width direction. Will cause variation. On the other hand, in the modified example 3, the holding member 122 protrudes toward the developing sleeve 5a from the magnetic plate 121, and the magnetic plate 121 does not have a through hole. Thereby, it is possible to suppress variation in the amount of developer passing through the doctor gap D depending on the position in the width direction, and it is possible to suppress the occurrence of density unevenness in the developed image.
Since the second embodiment is the same as the second modification except that the holding member 122 protrudes from the magnetic plate 121, the third modification also secures the fixing property of the magnetic plate 121 to the holding member 122 as in the first embodiment, and the developing device 4. It is possible to suppress the occurrence of density unevenness in the developed image when used in the above.

  In the configuration in which the magnetic plate 121 is separated from the developing roller 5 rather than the holding member 122 as in Modification 3, the developer regulated by the holding member 122 on the downstream side of the magnetic plate 121 is in the vicinity of the front end surface of the magnetic plate 121. There is a risk of staying in this space (the space indicated by “G” in FIG. 8). When the developer stays in the vicinity of the front end surface of the magnetic plate 121, the toner in the remaining developer adheres to the front end surface or the like of the magnetic plate 121, and the agglomerated toner adheres to the developing roller more than the front end surface of the holding member 122. 5 may approach the doctor gap D. In the portion where the doctor gap D is narrowed, the amount of developer supplied to the development area A is reduced, and the image density may be reduced.

On the other hand, as in the first embodiment, the first modification, and the second modification, the developing roller 5 in the developing doctor 12 is obtained by bringing the tip surface of the magnetic plate 121 closer to the developing roller 5 than the tip surface of the holding member 122. It is possible to suppress the developer from staying on the front end surface facing the. As a result, it is possible to suppress a decrease in the amount of developer supplied to the development region A due to toner fixing to the development doctor 12.
Further, the front end surface of the magnetic plate 121 and the front end surface of the holding member 122 may be arranged so as to be flush with each other (a flat state without a step). However, if they are flush with each other, there is a risk that the tip end surface of the holding member 122 may protrude due to an accuracy error or assembly error of the member, so that the tip end surface of the magnetic plate 121 protrudes as in the first embodiment. Thereby, it can prevent that the front end surface of the holding member 122 protrudes.

The development doctor 12 of Modification 3 regulates the height of the developer that has risen in the gap between the holding member 122 and the developing roller 5, but the magnetic force differs depending on the distance between the developing roller 5 and the magnetic material, and the spike rises. The density and shape of the developer are different. For this reason, even if the magnetic plate 121 does not protrude, the distance between the magnetic plate 121 and the developing roller 5 needs to be adjusted. Therefore, in the configuration in which the holding member 122 protrudes as in the third modification, first, the gap between the holding member 122 and the developing roller 5 is adjusted with high accuracy, and further, the magnetic plate 121 attached to the holding member 122 and the developing It is necessary to adjust the gap with the roller 5 with high accuracy.
On the other hand, as in the first embodiment or the like, if the magnetic plate 121 is protruded, the magnetic plate 121 may be the only member that accurately adjusts the distance from the developing roller 5.

[Example 2]
FIG. 9 is an explanatory diagram of a second embodiment of the developing doctor 12 (hereinafter referred to as “embodiment 2”). FIG. 9A is a schematic cross-sectional view of a cross section orthogonal to the longitudinal direction of the developing doctor 12. FIG. 9B is a schematic cross-sectional view of the developing doctor 12 taken along the line HH in FIG. Fig.9 (a) is sectional drawing in the EE cross section in FIG.9 (b). The arrow “F” in FIG. 9A indicates the rotation direction of the developing sleeve 5 a that the front end surface of the developing doctor 12 faces.

The magnetic plate 121 of the developing doctor 12 of Example 2 shown in FIG. 9 does not have a through hole in the range of the image area α in the longitudinal direction (left and right direction in FIG. 9B). It has a uniform cross section in the shape shown in a).
The holding member 122 includes an upstream holding member 122b that contacts the upstream plate surface of the magnetic plate 121 in the surface movement direction of the developing sleeve 5a, and a downstream holding member that contacts the downstream plate surface of the magnetic plate 121. 122c. The developing doctor 12 according to the second embodiment illustrated in FIG. 9 includes holes at a plurality of positions in the longitudinal direction of the upstream holding member 122b, and the downstream holding member 122c passes through the hole of the upstream holding member 122b. Convex part 122d is provided.

In the developing doctor 12 of Example 2 shown in FIG. 9, the upstream side holding member 122b and the downstream side holding member 122c are in contact with the plate surface of the magnetic plate 121, and the non-penetrated through the hole of the upstream side holding member 122b. The tip of the magnetic member convex portion 122d is crushed and crimped. Thereby, the holding member 122 contacts both of the two plate surfaces of the magnetic plate 121 to hold the magnetic plate 121.
Furthermore, the magnetic plate 121 has a rough surface treatment portion 121d that has been subjected to rough surface treatment for roughening the surface as a process for forming irregularities on the surface in a range where the magnetic plate 121 contacts the holding member 122 on the downstream plate surface. In the second embodiment, a rough surface treatment is performed by rubbing a portion of the plate surface of the magnetic plate 121 that is desired to be the rough surface treatment portion 121d with sandpaper. The rough surface treatment is not limited to the one using sandpaper, but may be any process that forms irregularities on the plate surface of the magnetic plate 121.

The magnetic plate 121 does not have a through hole in the image region α in the longitudinal direction, and is supported from both sides in the plate thickness direction by an upstream holding member 122b and a downstream holding member 122c made of resin or a nonmagnetic metal member. Yes.
Since the magnetic plate 121 has no through-holes within the image area α and has a uniform cross section, it is possible to prevent variations in the strength of the magnetic field formed by the magnetic plate 121 and the magnet roller 5b, and the doctor gap D The variation in the amount of developer passing through can be suppressed. As a result, the occurrence of density unevenness in the developed image developed on the surface of the photoreceptor 1 can be suppressed, and the quality of the image formed on the transfer paper can be improved.

The upstream holding member 122b and the downstream holding member 122c are in contact with the two plate surfaces of the magnetic plate 121, respectively. Thereby, it is possible to prevent the magnetic plate 121 from moving in a direction parallel to the moving direction of the developing sleeve 5a at the position facing the magnetic plate 121 (the left-right direction in FIG. 9A).
Further, in the developing doctor 12 according to the second embodiment, the magnetic plate 121 includes the rough surface processing unit 121d, and the contact surface on the holding member 122 (“downstream holding member 122c” in the second embodiment) side which is a nonmagnetic member. The frictional force between is increased. By increasing the frictional force between the plate surface of the magnetic plate 121 and the contact surface of the holding member 122, the magnetic plate 121 is inhibited from moving in the surface direction with respect to the holding member 122. For this reason, it is possible to prevent the magnetic plate 121 from falling off the holding member 122 and to secure the fixing property of the magnetic plate 121 to the holding member 122.
As described above, the developing doctor 12 according to the second exemplary embodiment can suppress the occurrence of uneven density of the developed image when used in the developing device 4 while securing the magnetic plate 121 to the holding member 122.

  The magnetic plate 121 of Example 2 does not have a through hole in the image region α in the longitudinal direction, and has a rough surface processing portion 121d. Further, the upstream side holding member 122b and the downstream side holding member 122c constituting the holding member 122 are made of a nonmagnetic resin material or a nonmagnetic metal material, and are caulked so as to be supported from both sides in the thickness direction of the magnetic plate 121. Be joined. Thereby, the developer can be regulated uniformly in the longitudinal direction while maintaining the rigidity of the developing doctor 12. The joining method of the upstream holding member 122b and the downstream holding member 122c is not limited to caulking, and other joining methods such as fastening with screws or adhesion using an adhesive may be used.

  As a combination of materials of the upstream side holding member 122b and the downstream side holding member 122c, both the upstream side holding member 122b and the downstream side holding member 122c may be nonmagnetic metal materials or nonmagnetic resin materials. Alternatively, one of the upstream holding member 122b and the downstream holding member 122c may be a member made of a nonmagnetic metal material, and the other may be a member made of a nonmagnetic resin material.

  As the upstream holding member 122b and the downstream holding member 122c, materials having different rigidity may be used. As a result, the low-rigidity member is deformed along the surface of the high-rigidity member at the joint surface where the upstream-side holding member 122b and the downstream-side holding member 122c are in contact, and the upstream-side holding member 122b and the downstream-side holding member 122c can be brought into close contact with each other.

  FIG. 10 is an explanatory diagram of two modified examples of the developing doctor 12 in which the surface of the magnetic plate 121 is processed to form irregularities on the surface thereof in the range in contact with the holding member 122 on the surface of the magnetic plate 121 as in the second embodiment. .

[Modification 4]
FIG. 10A is a schematic cross-sectional view of a first modified example (hereinafter referred to as “modified example 4”) of the developing doctor 12 that has been processed to form irregularities on the surface of the magnetic plate 121.

In the developing doctor 12 of Modification 4 shown in FIG. 10A, a holding member 122 is formed by integral molding with respect to the magnetic plate 121 having the rough surface processing portion 121d so as to cover other than the lower portion of the magnetic plate 121. ing.
In the configuration in which the holding member 122 is formed by integral molding, the magnetic plate 121 includes the rough surface processing portion 121d, so that the adhesive force between the plate surface provided with the rough surface processing portion 121d and the holding member 122 is improved. Thereby, it is possible to prevent the magnetic plate 121 from falling off the holding member 122 and to secure the fixing property of the magnetic plate 121 to the holding member 122.

[Modification 5]
FIG. 10B is a schematic cross-sectional view of a second modified example (hereinafter referred to as “modified example 5”) of the developing doctor 12 that has been processed to form irregularities on the surface of the magnetic plate 121.

In the developing doctor 12 of Modification 5 shown in FIG. 10B, the portion of the magnetic plate 121 covered with the holding member 122 is formed with unevenness on the plate surface so that the cross section is corrugated by pressing, and the holding member 122. Are formed on the magnetic plate 121 by integral molding.
In the configuration shown in FIG. 10B, an uneven shape can be formed on both of the two plate surfaces of the magnetic plate 121 by performing press working so that the cross section is corrugated.
By forming the holding member 122 on the magnetic plate 121 by integral molding, the adhesive force between the two plate surfaces on which the irregularities are formed and the holding member 122 is improved. Thereby, it is possible to prevent the magnetic plate 121 from falling off the holding member 122 and to secure the fixing property of the magnetic plate 121 to the holding member 122.
Embossing can also be used as a process for forming irregularities on the surface of the magnetic plate 121.

Example 3
FIG. 11 is an explanatory diagram of a third embodiment of the developing doctor 12 (hereinafter referred to as “Example 3”). FIG. 11A is a schematic cross-sectional view at a position within the range of the image region α, which is a cross-section orthogonal to the longitudinal direction of the developing doctor 12. FIG. 11B is a schematic cross-sectional view at a position where the hole 121a is provided in the magnetic plate 121 which is a cross section orthogonal to the longitudinal direction of the developing doctor 12 and is outside the range of the image region α. FIG. 11C is a schematic cross-sectional view of the developing doctor 12 taken along the line HH in FIGS. 11A and 11B. 11A is a cross-sectional view taken along the line EE in FIG. 11C, and FIG. 11B is a cross-sectional view taken along the line II in FIG. 11C. The arrow “F” in FIGS. 11A and 11B is the rotation direction of the developing sleeve 5a that the front end surface of the developing doctor 12 faces.

  The magnetic plate 121 of the developing doctor 12 of Example 3 shown in FIG. 11 does not have a through hole in the range of the image area α in the longitudinal direction (left-right direction in FIG. 11C), and FIG. It has a uniform cross section in the shape shown in a). And the magnetic plate 121 of Example 3 is provided with the hole part 121a which is a through-hole outside the range of the image area | region (alpha) in a longitudinal direction. The holding member 122 includes an upstream holding member 122b that contacts the upstream plate surface of the magnetic plate 121 in the surface movement direction of the developing sleeve 5a, and a downstream holding member that contacts the downstream plate surface of the magnetic plate 121. 122c. The developing doctor 12 of Example 3 shown in FIG. 11 is provided with a boss portion 122e in the downstream holding member 122c and a boss receiving hole 122f in the upstream holding member 122b outside the range of the image area α in the longitudinal direction. ing.

  In the developing doctor 12 of Example 3 shown in FIG. 11, when the magnetic plate 121 is sandwiched between the upstream side holding member 122b and the downstream side holding member 122c, the boss part 122e has a hole part 121a as shown in FIG. 11B. Is inserted into the boss receiving hole 122f.

The magnetic plate 121 does not have a through hole in the image region α in the longitudinal direction, and is supported from both sides in the plate thickness direction by an upstream holding member 122b and a downstream holding member 122c made of resin or a nonmagnetic metal member. Yes.
Since the magnetic plate 121 has no through-holes within the image area α and has a uniform cross section, it is possible to prevent variations in the strength of the magnetic field formed by the magnetic plate 121 and the magnet roller 5b, and the doctor gap D The amount of developer passing through can be kept constant. As a result, the occurrence of density unevenness in the developed image developed on the surface of the photoreceptor 1 can be suppressed, and the quality of the image formed on the transfer paper can be improved.

The upstream holding member 122b and the downstream holding member 122c are in contact with the two plate surfaces of the magnetic plate 121, respectively. Thereby, it is possible to prevent the magnetic plate 121 from moving in a direction parallel to the moving direction of the developing sleeve 5a at the position facing the magnetic plate 121 (the left-right direction in FIGS. 11A and 11B).
Further, in the developing doctor 12 according to the third embodiment, the boss portion 122e of the downstream holding member 122c passes through the hole 121a provided outside the image region α in the longitudinal direction of the magnetic plate 121, and the magnetic plate 121 is in the surface direction. Prevent moving to. Thereby, it is possible to prevent the magnetic plate 121 from falling off the holding member 122 and to secure the fixing property of the magnetic plate 121 to the holding member 122.
As described above, the developing doctor 12 according to the third exemplary embodiment can suppress the density unevenness of the developed image when used in the developing device 4 while ensuring the fixing property of the magnetic plate 121 to the holding member 122.

  The magnetic plate 121 of Example 3 does not have a through hole in the image area α in the longitudinal direction, and has a through hole outside the image area α. Further, the upstream side holding member 122b and the downstream side holding member 122c constituting the holding member 122 are made of a nonmagnetic resin material or a nonmagnetic metal material. The upstream side holding member 122b and the downstream side holding member 122c are joined by fitting the boss portion 122e and the boss receiving hole 122f so as to be supported from both sides in the thickness direction of the magnetic plate 121. The magnetic plate 121 and the holding member 122 are accurately positioned by fitting the boss portion 122e into the hole portion 121a which is a through hole of the magnetic plate 121. Thereby, the developer can be regulated uniformly in the longitudinal direction while maintaining the rigidity of the developing doctor 12.

  In the third embodiment, the protrusion (boss 122e) that fits into the hole 121a of the magnetic plate 121 is provided on the downstream holding member 122c. However, such a protrusion may be provided on the upstream holding member 122b. Good. Further, the upstream holding member 122b and the downstream holding member 122c are joined by fitting the boss portion 122e penetrating the hole portion 121a and the boss receiving hole 122f. The method for joining these two members is not limited to this. As in the developing doctor 12 of the second embodiment shown in FIG. 9, two members may be joined by caulking. In addition, other joining methods may be used, such as adhering portions where the surfaces of the two members are in contact with each other with an adhesive.

[Modification 6]
FIG. 12 is an explanatory diagram of a modified example (hereinafter referred to as “modified example 6”) of the developing doctor 12 in which the hole 121a is provided outside the image area α in the longitudinal direction of the magnetic plate 121 as in the third embodiment. is there.
FIG. 12A is a schematic cross-sectional view at a position within the range of the image region α, which is a cross-section orthogonal to the longitudinal direction of the developing doctor 12. 12B is a schematic cross-sectional view at a position where the hole 121a is provided in the magnetic plate 121 which is a cross section orthogonal to the longitudinal direction of the developing doctor 12 and is outside the range of the image region α. FIG. 12C is a schematic cross-sectional view of the developing doctor 12 taken along the line HH in FIGS. 12A and 12B. 12A is a cross-sectional view taken along the line EE in FIG. 12C, and FIG. 12B is a cross-sectional view taken along the line II in FIG. 12C. The arrow “F” in FIGS. 12A and 12B is the rotation direction of the developing sleeve 5a that the front end surface of the developing doctor 12 faces.

In the developing doctor 12 of Modification 6, the holding member 122 is integrally formed with the magnetic plate 121 having the hole 121a outside the image area α in the longitudinal direction so as to cover the portion other than the lower portion of the magnetic plate 121. ing.
At the time of integral molding, the hole 121a is filled with the material of the holding member 122 that has become liquid, and then the material is cured to form the holding member 122. As shown in FIG. The part enters the hole 121a to form a fitting shape with respect to the hole 121a. Since the holding member 122 enters the hole portion 121a, the adhesive force between the holding member 122 and the plate surface provided with the roughened surface processing portion 121d is improved. Thereby, it is possible to prevent the magnetic plate 121 from falling off the holding member 122 and to secure the fixing property of the magnetic plate 121 to the holding member 122.

In each of the above-described embodiments, as a configuration for preventing the magnetic plate 121 from falling off the holding member 122, the first embodiment has a bent portion 121c, the second embodiment has a rough surface processing portion 121d, and the third embodiment. Has a hole 121a that fits the holding member 122 outside the image area α.
Two or more configurations that prevent the magnetic plates 121 from falling off may be combined. For example, the surface of the magnetic plate 121 having the hole 121a that fits the holding member 122 outside the image area α of the third embodiment is roughened as in the second embodiment to roughen the surface. A surface processing unit 121d may be provided. As a result, it is possible to realize a configuration in which the magnetic plate 121 is less likely to come off from the holding member 122 than in the configurations of the second and third embodiments. The configuration is not limited to the combination of the second embodiment and the third embodiment, and may be a configuration in which the first embodiment is combined with another embodiment or a configuration in which all of the first to third embodiments are combined.

  The developing device 4 including the developing doctor 12 having the configuration of each of the above-described embodiments and modifications can suppress the occurrence of density unevenness in the developed image. Further, the copying machine 500 including such a developing device 4 can suppress the occurrence of density unevenness in the image formed by transferring the image developed by the developing device 4 to a recording medium such as transfer paper.

  What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.

(Aspect A)
A developer such as a developing doctor 12 disposed opposite to the surface of a developer carrier such as the developing roller 5 in a configuration in which a magnetic member such as a plate-like magnetic plate 121 is fixed to a nonmagnetic member such as the holding member 122. In the restricting member, the nonmagnetic member contacts the magnetic member from both sides in the plate thickness direction of the magnetic member, and the magnetic member is in a range (image region α) opposite to a range in which the surface of the developer carrier is developed in the longitudinal direction. Etc.) It is characterized by not having a through hole in the inside.
As a result of extensive investigations by the present inventors, in the configuration in which the magnetic member is fixed to the non-magnetic member by conventional caulking, the developer carrying amount after being regulated by the developer regulating member is caulked to the magnetic member. It was found that the portion provided with the through hole was different from the other portion. This is thought to be due to the following reasons.
That is, in the portion where the through hole is provided in the magnetic member, the amount of the magnetic body facing the developer carrier is smaller than in the other portions, and the strength of the magnetic field formed between the developer carrier and the magnetic member Also become weaker. Further, the developer magnetic brush formed on the surface of the developer carrying member by the magnetic force becomes sparse as the magnetic field strength increases, and becomes dense as the magnetic field strength decreases. For this reason, in the portion where the through hole is provided in the magnetic member, the strength of the magnetic field is weakened, and the magnetic brush becomes denser than the other portion, so the developer carrying amount after being regulated by the developer regulating member is More than other parts. Therefore, it is considered that the developer carrying amount after being regulated by the developer regulating member is different between the portion where the through hole is provided in the magnetic member and the other portion.
The developer restricting member of aspect A does not have a through hole in a range opposite to a range where the surface of the developer carrying member in the longitudinal direction of the magnetic member is developed. It is possible to prevent the difference in the developer carrying amount due to the difference in strength. Thereby, in the range which develops, it can suppress that the carrying amount of a developer varies, and can suppress the generation of density unevenness in the developed image. In the developer regulating member of aspect A, the magnetic member can be fixed to the non-magnetic member by sandwiching the non-magnetic member in contact with the magnetic member from both sides in the plate thickness direction of the magnetic member.
Therefore, in the aspect A, it is possible to suppress the occurrence of density unevenness of the image when the magnetic member is fixed to the nonmagnetic member and used in the developing device.

(Aspect B)
In aspect A,
The magnetic member such as the magnetic plate 121 has a bent portion such as a bent portion 121c that contacts a non-magnetic member such as the holding member 122 at the end opposite to the side facing the surface of the developer carrying member such as the developing roller 5. It is characterized by having.
In the conventional configuration in which the magnetic member is fixed to the nonmagnetic member by caulking, the convex portion of the nonmagnetic member is passed through the through hole of the magnetic member, and the tip of the convex portion passing through the through hole is crushed and caulked. By caulking, the magnetic member and the non-magnetic member are brought into close contact with each other by sandwiching the magnetic member between the collapsed portion of the tip of the convex portion and the main body of the non-magnetic member, and not only in the plate thickness direction but also in the plate thickness direction. It is possible to prevent the magnetic member from moving in the orthogonal direction (hereinafter referred to as “plane direction”). Therefore, the position of the magnetic member relative to the nonmagnetic member can be fixed in both the plate thickness direction and the surface direction, and the magnetic member can be fixed relative to the nonmagnetic member. Also in the aspect B, the magnetic member can be fixed to the nonmagnetic member as follows.
That is, in the developer regulating member according to aspect B, the nonmagnetic member contacts the magnetic member from both sides in the plate thickness direction, thereby fixing the position of the magnetic member relative to the nonmagnetic member in the plate thickness direction. Furthermore, the magnetic member has a bent portion at the end opposite to the side facing the surface of the developer carrier, so that the magnetic member is in the surface direction and the bent portion contacts the non-magnetic member. When trying to move, the bent portion is caught by the non-magnetic member, and movement in the surface direction can be hindered. By fixing the positions in both the plate thickness direction and the surface direction, the magnetic member can be fixed to the nonmagnetic member.

(Aspect C)
In the aspect A or B, the cross section is corrugated in at least a part (rough surface treatment portion 121d, etc.) of the range where the nonmagnetic member such as the holding member 122 contacts on the surface in the thickness direction of the magnetic member such as the magnetic plate 121 A process for forming irregularities such as press working and rough surface treatment is performed.
According to this, as described in the second embodiment, the frictional force between the surface of the magnetic member in the plate thickness direction and the contact surface of the nonmagnetic member can be increased, and the magnetic member is compared with the nonmagnetic member. Hinders movement in the surface direction. By fixing the positions in both the plate thickness direction and the surface direction, the magnetic member can be fixed to the nonmagnetic member.

(Aspect D)
In any one of the aspects A to C, the magnetic member such as the magnetic plate 121 is in a range (image region α or the like) that is opposed to a range in which the surface of the developer carrier such as the developing roller 5 is developed in the longitudinal direction. A non-magnetic member such as the holding member 122 has a fitting shape such as a boss portion 122e that fits into the through hole.
According to this, as described in Example 3 and the like, the position of the magnetic member relative to the nonmagnetic member in the surface direction can be fixed by fitting the fitting shape of the nonmagnetic member into the through hole of the magnetic member. By fixing the positions in both the plate thickness direction and the surface direction, the magnetic member can be fixed to the nonmagnetic member.

(Aspect E)
In any one of the aspects A to D, the nonmagnetic member such as the holding member 122 is a member made of a resin material and formed by integral molding with respect to the magnetic member such as the magnetic plate 121.
According to this, as described in the above embodiment, it is possible to realize a configuration in which the nonmagnetic member is held in contact with the magnetic member from both sides in the plate thickness direction to hold the magnetic member.

(Aspect F)
In any of the aspects A to D, the nonmagnetic member such as the holding member 122 is a first nonmagnetic member such as the upstream holding member 122b that is in contact with one surface of the magnetic member such as the magnetic plate 121 in the plate thickness direction. It is a member formed by joining a plurality of members including a member and a second nonmagnetic member such as a downstream holding member 122c in contact with the other surface.
According to this, as described in the above embodiment, it is possible to realize a configuration in which the nonmagnetic member is held in contact with the magnetic member from both sides in the plate thickness direction to hold the magnetic member.

(Aspect G)
In aspect F, the first nonmagnetic member such as the upstream holding member 122b and the second nonmagnetic member such as the downstream holding member 122c are nonmagnetic resin members or nonmagnetic metal members.
According to this, as described in the above embodiment, as the non-magnetic member, both a resin member and a metal member can be used as long as they are non-magnetic.

(Aspect H)
In any of the aspects A to G, the nonmagnetic property of the holding member 122 or the like that contacts the upstream surface of the developer carrying member such as the developing roller 5 in the plate thickness direction of the magnetic member such as the magnetic plate 121 or the like. An end surface of the member facing the developer carrying member is inclined so as to approach the developer carrying member as the downstream side of the developer carrying member moves in the surface direction.
According to this, as explained in Modification 1 above, it is possible to suppress a change in the developer speed when the developer is regulated by the magnetic member, and to suppress the deterioration of the developer, which deteriorates and the fluidity deteriorates. It is possible to suppress a decrease in the pumping amount due to retention of the developer.

(Aspect I)
The developer is carried on the surface by the magnetic force of the magnetic field generating means such as the magnet roller 5b disposed therein, and the developer is moved to the surface so that the developer is opposed to the latent image carrier such as the photosensitive member 1 or the like. A developer carrying member such as the developing roller 5 to be conveyed to the developer carrying member, and a developer regulating means that faces the developer carrying member in the width direction of the developer carrying member and regulates the developer passing through the opposed portion. In the developing device such as the developing device 4, a developer regulating member such as the developing doctor 12 according to any one of aspects A to H is used as the developer regulating means.
According to this, as described in the above embodiment, it is possible to suppress the occurrence of density unevenness in the image developed by the developing device.

(Aspect J)
In an image forming apparatus such as a copying machine 500 including an image carrier such as the photosensitive member 1 and a developing unit that develops a latent image formed on the image carrier with a developer, the development according to aspect I is used as the developing unit. A developing device such as the device 4 is provided.
According to this, as described in the above embodiment, it is possible to suppress the occurrence of density unevenness in the image formed by transferring the image developed by the developing device onto a recording medium such as transfer paper.

DESCRIPTION OF SYMBOLS 1 Photoconductor 1K Photoconductor 1Y for Black 2 Photoconductor for yellow 2 Discharge conveyance path 2a Discharge conveyance screw 4 Developing device 5 Developing roller 5a Development sleeve 5b Magnet roller 6 Collection screw 7 Collection conveyance path 8 Supply screw 9 Supply conveyance path 9a Developer Discharge port 10 Stirring conveyance path 11 Stirring screw 12 Developing doctor 14 Stretching roller 15 Belt drive roller 16 Secondary transfer backup roller 17 Intermediate transfer unit 18 Process cartridge 19 Belt cleaning device 20 Image forming unit 21 Optical writing unit 22 Secondary transfer Device 23 Conveying stretch roller 24 Paper conveying belt 25 Fixing device 26 Fixing belt 27 Pressure roller 30 Document table 32 Contact glass 33 First traveling member 34 Second traveling member 35 Imaging lens 36 Reading sensor 40 Developing case 42 Feeding roller 43 Paper Bar Link 44 Paper feed cassette 45 Separation roller 46 Paper feed path 47 Transport roller pair 49 Registration roller pair 60 Manual paper feed roller 61 Manual feed tray 62 Manual separation roller 63 Manual paper feed path 64 Paper discharge roller pair 65 Stack unit 71 Charging unit 71a Charging Roller 71b Charging roller cleaner 72 Drum cleaning unit 72a Cleaning blade 72b Discharge screw 72c Discharge member 73 Primary transfer roller 100 Printer unit 110 Intermediate transfer belt 120 Heat dissipating part 121 Magnetic plate 121a Hole part 121b Main body part 121c Bending part 121d Rough surface processing part 122 Holding member 122a Convex portion 122b Upstream holding member 122c Downstream holding member 122d Holding member convex portion 122e Boss portion 122f Boss receiving hole 133 First partition wall 134 Second partition wall 135 Third partition wall 200 Paper feeder 300 Scanner 400 Automatic document feeder 500 Copying machine A Development area B Collection port D Doctor gap α Image area

JP2015-55642A

Claims (10)

In the developer regulating member arranged to face the surface of the developer carrying member of the developing device in a configuration in which the plate-like magnetic member is fixed to the non-magnetic member,
The non-magnetic member is in contact with the magnetic member from both sides in the thickness direction of the magnetic member,
The developer regulating member according to claim 1, wherein the magnetic member does not have a through hole in a range opposite to a range in which the surface of the developer carrying member is developed in the longitudinal direction. The developer regulating member according to claim 1,
The developer regulating member according to claim 1, wherein the magnetic member has a bent portion in contact with the non-magnetic member at an end opposite to the side facing the surface of the developer carrying member. In the developer regulating member according to claim 1 or 2,
A developer regulating member, wherein at least a part of a range where the nonmagnetic member is in contact with the surface of the magnetic member in the plate thickness direction is subjected to a process for forming irregularities. In the developer regulating member according to any one of claims 1 to 3,
The magnetic member has the through hole on the outer side of a range facing a range where the surface of the developer carrying member in the longitudinal direction is developed.
The developer regulating member, wherein the nonmagnetic member has a fitting shape that fits into the through hole. In the developer regulating member according to any one of claims 1 to 4,
The developer regulating member, wherein the nonmagnetic member is a member made of a resin material and integrally formed with the magnetic member. In the developer regulating member according to any one of claims 1 to 4,
The nonmagnetic member is formed by joining a plurality of members including a first nonmagnetic member that contacts one surface of the magnetic member in the plate thickness direction and a second nonmagnetic member that contacts the other surface. A developer regulating member, which is a formed member. The developer regulating member according to claim 6,
The developer regulating member, wherein the first nonmagnetic member and the second nonmagnetic member are a nonmagnetic resin member or a nonmagnetic metal member. In the developer regulating member according to any one of claims 1 to 7,
The end surface of the non-magnetic member that is in contact with the surface upstream of the developer carrying member in the plate thickness direction of the magnetic member and facing the developer carrying member is the surface moving direction of the developer carrying member. A developer regulating member, wherein the developer regulating member is inclined so as to approach the developer carrying member toward the downstream side. A developer carrying member for carrying the developer on the surface by the magnetic force of the magnetic field generating means disposed inside, and transporting the developer to a developing region facing the latent image carrier by moving the surface;
In a developing device, comprising: a developer regulating means that faces the developer carrying body across the width direction of the developer carrying body and regulates the developer that passes through the facing portion.
A developing device using the developer regulating member according to claim 1 as the developer regulating means. An image carrier;
An image forming apparatus comprising: a developing unit that develops the latent image formed on the image carrier with a developer;
An image forming apparatus comprising the developing device according to claim 9 as the developing unit.

Images