JP2018205619A - Developing device and image forming apparatus - Google Patents

Abstract

To provide a developing device that can reduce attachment of toner to a regulation unit, and an image forming apparatus.SOLUTION: A developing device comprises: a magnetic roller 134 that conveys developer; a regulation member 135 that regulates the amount of developer conveyed by the magnetic roller 134; a wall part 141B that faces an outer peripheral surface 134A1 of the magnetic roller 134 downstream in the rotation direction D6 of the magnetic roller 134 with respect to the regulation member 135; a magnet M7 that is provided on the wall part 141B and has the N pole arranged toward the outer peripheral surface 134A1; and a magnet M3 that is provided inside the magnetic roller 134 and has the S pole arranged toward the N pole of the magnet M7.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electrophotographic image forming apparatus and a developing device mounted on the image forming apparatus.

  An image forming apparatus such as a printer capable of forming an image by an electrophotographic method is provided with a developing device. The developing device develops an electrostatic latent image formed on an image carrier such as a photosensitive drum using toner contained in the developer. This type of developing device includes a conveyance roller, a regulating unit, a developing roller, and the like. The conveying roller conveys the developer to a position facing the developing roller by carrying and rotating the developer accommodated in the accommodating portion in the housing of the developing device on the outer peripheral surface. The regulating unit regulates the amount of developer transported by the transport roller by contacting the developer carried on the outer peripheral surface of the transport roller. The developing roller supplies the toner supplied from the conveying roller at the facing position to the image carrier.

  In the developing device, a wall portion facing the outer peripheral surface of the transport roller may be provided on the downstream side in the rotation direction of the transport roller with respect to the regulating portion. In this type of developing device, the toner that is scattered at the facing position or the like and floats inside the housing may enter the space between the wall portion and the outer peripheral surface of the transport roller and adhere to the regulating portion. Further, the toner adhering to the restricting portion may aggregate. When the agglomerated toner moves from the restricting portion to the transport roller, the agglomerated toner is used for development, and there is a possibility that a problem such as a decrease in density reproducibility in a printed image may occur. On the other hand, a developing device that rotates a conveyance roller in a direction opposite to that at the time of printing and returns toner adhering to a regulation unit to a storage unit is known as a conventional technique (see Patent Document 1).

Japanese Patent Laying-Open No. 2014-6411

  By the way, in the image forming apparatus, when the process of rotating the transport roller in the direction opposite to that during printing is performed, the use of the image forming apparatus by the user is restricted during the execution period of the process. For this reason, it is desirable to suppress toner adhesion to the restricting portion as much as possible.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device and an image forming apparatus capable of suppressing toner adhesion at a restricting portion.

  A developing device according to one aspect of the present invention includes a housing, a transport roller, a regulating portion, a wall portion, a first magnetic pole member, and a magnetic field forming portion. The housing accommodates a developer including a magnetic carrier and a non-magnetic toner. The transport roller has an outer peripheral surface for carrying the developer, is rotatably provided inside the housing, and the developer is determined in advance by supporting the developer on the outer peripheral surface and rotating. Transport along the transport path. The restricting portion is provided to face the outer peripheral surface across the conveyance path, and regulates the developer conveyance amount by the conveyance roller. The wall portion opposes the outer peripheral surface on the downstream side in the transport direction of the developer by the transport roller with respect to the regulating portion. The first magnetic pole member has a first magnetic pole having a predetermined polarity, is provided on the wall portion, and the first magnetic pole member is disposed toward the outer peripheral surface. The magnetic field forming unit is provided inside the transport roller, and forms a magnetic field from one of the outer peripheral surface and the wall portion toward the other between the outer peripheral surface and the wall portion.

  An image forming apparatus according to another aspect of the present invention includes the developing device.

  According to the present invention, it is possible to suppress adhesion of toner in the restricting portion.

FIG. 1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of an image forming unit in the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram showing a configuration of the developing unit in the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a diagram illustrating a configuration of the guide unit in the image forming apparatus according to the embodiment of the present invention. FIG. 5 is a diagram illustrating a configuration of the guide unit in the image forming apparatus according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

  For convenience of explanation, the vertical direction is defined as the vertical direction D1 in the installation state in which the image forming apparatus 10 can be used (the state shown in FIG. 1). Also, the front-rear direction D2 is defined with the left surface of the image forming apparatus 10 shown in FIG. Further, the left-right direction D3 is defined with reference to the front of the image forming apparatus 10 in the installed state.

[Schematic Configuration of Image Forming Apparatus 10]
First, a schematic configuration of an image forming apparatus 10 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a schematic cross-sectional view showing the configuration of the image forming apparatus 10. FIG. 2 is a schematic cross-sectional view showing the configuration of the image forming unit 1.

  The image forming apparatus 10 is a color printer that forms an image based on image data input from an information processing apparatus on a sheet-like paper by an electrophotographic method. A facsimile, a copier, a multifunction machine, and the like are also examples of the image forming apparatus according to the present invention.

  As shown in FIG. 1, the image forming apparatus 10 includes a plurality of image forming units 1 to 4, an intermediate transfer belt 5, an optical scanning device 6, a secondary transfer roller 7, a fixing device 8, a paper discharge tray 9, and a toner container. 21 to 24, a paper feed cassette 31, a conveyance path 32, and the like.

  The image forming apparatus 10 is a so-called tandem type. The image forming units 1 to 4 are arranged in parallel along the belt rotation direction D4 (see FIG. 1) of the intermediate transfer belt 5. A toner image corresponding to Y (yellow) in the image forming unit 1, M (magenta) in the image forming unit 2, C (cyan) in the image forming unit 3, and K (black) in the image forming unit 4 is formed.

  As shown in FIG. 2, the image forming unit 1 includes a photosensitive drum 11 (an example of an image carrier in the present invention), a charging unit 12 provided corresponding to the photosensitive drum 11, a developing unit 13, a primary unit. A transfer roller 15 and a cleaning device 16 are provided. Since the image forming units 2 to 4 are configured in the same manner, the description thereof is omitted here.

  Each of the photosensitive drums 11 is arranged along the belt rotation direction D4 of the intermediate transfer belt 5. The photosensitive drum 11 is an image carrier that carries an electrostatic latent image and a toner image. The photosensitive drum 11 is long in the left-right direction D3 and has a rotation shaft 111 extending along the left-right direction D3. The photosensitive drum 11 is rotatable in the rotation direction D5 (see FIG. 2) by the rotation shaft 111 being rotatably supported by the housing of the image forming apparatus 10.

  Each charging unit 12 includes a charging roller 121. The charging unit 12 uses the charging roller 121 to charge the photosensitive drum 11 to a predetermined potential with electric power supplied from a power source (not shown). The photosensitive drum 11 charged by the charging unit 12 is irradiated with laser light by the optical scanning device 6, and an electrostatic latent image based on the image data is formed on the outer peripheral surface of the photosensitive drum 11.

  Each developing unit 13 develops the electrostatic latent image formed on the photosensitive drum 11 using a developer containing a non-magnetic toner and a magnetic carrier. The developing unit 13 will be described in detail later. The developing unit 13 is replenished with toner from removable toner containers 21 to 24 corresponding to the respective colors. The developer is mixed with an external additive for adjusting the charge amount and fluidity of the toner. For example, the external additive is titanium oxide or silica.

  Each primary transfer roller 15 transfers the toner image on the photosensitive drum 11 developed by the developing unit 13 to the intermediate transfer belt 5. The intermediate transfer belt 5 is a member to be transferred that travels above the photosensitive drums 11 of the image forming units 1 to 4 and to which toner images of respective colors formed on the photosensitive drums 11 are sequentially superimposed and transferred. . The toner image on the intermediate transfer belt 5 is transferred by the secondary transfer roller 7 to a sheet conveyed from the paper feed cassette 31 via the conveyance path 32. Thereafter, the toner image transferred to the paper is heated by the fixing device 8 and fixed on the paper. The paper on which the toner image has been fixed is discharged to the paper discharge tray 9.

  Each of the cleaning devices 16 includes a blade-shaped cleaning member 161 and a conveying member 162. The cleaning device 16 cleans the surface of the photosensitive drum 11 using the cleaning member 161. The toner removed from the surface of the photosensitive drum 11 by the cleaning member 161 is transported to a toner collection container (not shown) by the transport member 162.

[Configuration of Developing Unit 13]
Next, the configuration of the developing unit 13 will be described with reference to FIG. Here, FIG. 3 is a cross-sectional view showing a configuration of the developing unit 13. In FIG. 3, the photosensitive drum 11 is indicated by a broken line. In FIG. 3, the developer conveyance path R <b> 1 by the magnetic roller 134 is indicated by a one-dot chain line.

  As shown in FIG. 3, the developing unit 13 includes a housing 131, a first stirring member 132, a second stirring member 133, a magnetic roller 134, a regulating member 135, a developing roller 136, a first seal member 137, and a second seal. A member 138 and a guide portion 14 are provided. Here, the developing unit 13 is an example of a developing device in the present invention.

  The housing 131 has an accommodating space for accommodating the developer and the constituent members of the developing unit 13. As shown in FIG. 3, the housing 131 includes a plurality of members that form an outer surface of the developing unit 13 and an inner surface that defines the accommodation space.

  The casing 131 is long in the left-right direction D3. As shown in FIG. 3, a partition wall 131 </ b> A formed along the left-right direction D <b> 3 is provided at the bottom of the housing 131. A first developer container 131B and a second developer container 131C (see FIG. 3) that are long in the left-right direction D3 are formed on the bottom of the chassis 131 by the bottom, side walls, and the partition wall 131A of the chassis 131. ing. The developer is accommodated in each of the first developer accommodating portion 131B and the second developer accommodating portion 131C. The first developer accommodating portion 131B is provided with a first stirring member 132. The second developer accommodating portion 131C is provided with a second agitating member 133. Here, the first developer accommodating portion 131B and the second developer accommodating portion 131C are examples of the accommodating portions in the present invention.

  A supply space for supplying the toner contained in the developer to the photosensitive drum 11 is formed on the upper side of the second developer accommodating portion 131 </ b> C inside the housing 131. A magnetic roller 134, a regulating member 135, and a developing roller 136 are provided in the supply space.

  As shown in FIG. 3, an opening 131 </ b> D that opens rearward in the front-rear direction D <b> 2 is formed in the upper portion of the housing 131. A first seal member 137 and a second seal member 138 are provided in the opening 131D. A part of the peripheral surface of the developing roller 136 accommodated in the housing 131 is exposed from the opening 131D. The developing unit 13 is disposed inside the image forming apparatus 10 such that the circumferential surface of the developing roller 136 exposed from the opening 131 </ b> D faces the circumferential surface of the photosensitive drum 11.

  The first agitating member 132 agitates the developer accommodated in the first developer accommodating portion 131B and conveys the developer in one of the left and right directions D3. For example, the first stirring member 132 conveys the developer in the right direction (the front side in FIG. 3).

  For example, the first stirring member 132 is a conveying screw that is long in the left-right direction D3, and is provided rotatably in the first developer accommodating portion 131B. The developer conveyed by the first stirring member 132 is conveyed to the second developer accommodating portion 131C via a communication passage provided at the right end of the first developer accommodating portion 131B.

  The second agitating member 133 agitates the developer accommodated in the second developer accommodating portion 131 </ b> C and conveys the developer in a direction opposite to the first agitating member 132. For example, the second stirring member 133 conveys the developer in the left direction (the back side in FIG. 3).

  For example, like the first stirring member 132, the second stirring member 133 is a conveying screw that is long in the left-right direction D3, and is rotatably provided in the second developer accommodating portion 131C. The developer conveyed by the second agitating member 133 is conveyed to the first developer accommodating portion 131B via a communication passage provided at the left end of the second developer accommodating portion 131C.

  The carrier and the toner contained in the developer accommodated in the first developer accommodating portion 131B and the second developer accommodating portion 131C are agitated by the first agitating member 132 and the second agitating member 133, thereby causing friction. Charges up. As a result, a force attracting each other by electrostatic force acts between the toner and the carrier. Here, the first stirring member 132 and the second stirring member 133 are examples of the stirring member in the present invention.

  The magnetic roller 134 transports the developer from the second developer accommodating portion 131C to the developing roller 136 along a predetermined transport path R1 (see FIG. 3). Here, the magnetic roller 134 is an example of a transport roller in the present invention.

  As shown in FIG. 3, the magnetic roller 134 has a rotating sleeve 134A. The rotating sleeve 134A is a cylindrical member that is long in the left-right direction D3. The rotating sleeve 134 </ b> A is rotatably provided on the upper side of the second stirring member 133 inside the housing 131. The rotation sleeve 134A rotates in the rotation direction D6 shown in FIG. 3 by a rotation driving force supplied from a motor (not shown).

  Magnets M1 to M5 (see FIG. 3) are provided inside the rotating sleeve 134A. The magnets M1 to M5 are fixedly arranged at predetermined positions inside the rotating sleeve 134A. Specifically, the magnet M1 is disposed with the south pole facing the second stirring member 133 at a position facing the second stirring member 133 across the surface 134A1 (see FIG. 3) of the rotating sleeve 134A. Further, the magnet M2 is arranged with the N pole facing the restriction member 135 at a position facing the restriction member 135 with the surface 134A1 interposed therebetween. Further, the magnet M4 is disposed with the N pole facing the developing roller 136 at a position facing the developing roller 136 with the surface 134A1 interposed therebetween. Further, the magnet M3 is disposed at a position between the magnet M2 and the magnet M4 with the south pole facing the surface 134A1. In addition, the magnet M5 is arranged at a position between the magnet M4 and the magnet M1 with the south pole facing the surface 134A1.

  In the magnetic roller 134, the developer is supported on the surface 134A1 of the rotating sleeve 134A by the magnetic force generated by each of the magnets M1 to M5. For example, the magnet M1 magnetically attracts the carrier accommodated in the second developer accommodating portion 131C. As a result, the carrier and the toner that electrostatically adheres to the carrier are attracted to the surface 134A1. Therefore, the developer is carried on the surface 134A1 at the facing position P1 (see FIG. 3) where the magnet M1 and the second stirring member 133 face each other on the surface 134A1. Here, the surface 134A1 is an example of the outer peripheral surface in the present invention.

  The developer carried on the surface 134A1 of the rotating sleeve 134A is rotated by the rotating sleeve 134A in the rotation direction D6, so that the magnetic roller 134 and the developing roller 136 face each other from the facing position P1 (see FIG. 3). ) Along the transport route R1 leading to

  The regulating member 135 comes into contact with the developer conveyed by the magnetic roller 134 and regulates the conveyance amount of the developer by the magnetic roller 134. Here, the restricting member 135 is an example of a restricting portion in the present invention.

  For example, the regulating member 135 is a blade-like magnetic body that is long in the left-right direction D3. As shown in FIG. 3, the restricting member 135 is provided to face the surface 134A1 of the rotating sleeve 134A of the magnetic roller 134 with the transport path R1 interposed therebetween. Specifically, the regulating member 135 is provided to face the magnetic roller 134 at a facing position P2 (see FIG. 3) between the facing position P1 and the facing position P3 in the transport path R1. The facing position P2 is a position below the axis of the rotating sleeve 134A. The regulating member 135 is supported by the housing 131 in a posture inclined upward toward the axis of the rotating sleeve 134A.

  A predetermined gap is provided between the regulating member 135 and the surface 134A1 of the rotating sleeve 134A. In the gap, a magnetic field directed from the surface 134A1 to the regulating member 135 is formed by the magnet M2 and the regulating member 135 magnetized by the magnet M2. By the magnetic field, the developer carried on the surface 134A1 of the rotating sleeve 134A forms a magnetic brush that rises from the surface 134A1 along the direction of the magnetic field. When the magnetic brush formed on the surface 134A1 passes through the gap, the tip end side comes into contact with the regulating member 135 and is separated from the root side. As a result, the amount of developer transported by the magnetic roller 134 is regulated, and a developer layer having a uniform layer thickness is formed on the surface 134A1 of the rotating sleeve 134A.

  The developing roller 136 is provided on the upper side of the magnetic roller 134 so as to face the magnetic roller 134, and supplies the toner supplied from the magnetic roller 134 to the photosensitive drum 11 outside the housing 131.

  As shown in FIG. 3, the developing roller 136 has a rotating sleeve 136A. The rotating sleeve 136A is a cylindrical member that is long in the left-right direction D3. The rotating sleeve 136A is provided to face the magnetic roller 134 at the facing position P3, and is rotatably supported by the housing 131. The rotation sleeve 136A rotates in the rotation direction D7 shown in FIG. 3 by the rotation driving force supplied from the motor.

  Inside the rotating sleeve 136A, a magnet M6 (see FIG. 3) is provided. The magnet M6 is fixedly disposed at a predetermined position inside the rotating sleeve 136A. Specifically, the magnet M6 is disposed with the south pole facing the magnetic roller 134 at a position facing the magnetic roller 134 across the surface of the rotating sleeve 136A.

  The magnetic brush conveyed by the magnetic roller 134 passes through the facing position P2, and is then transported to the facing position P3. At the facing position P3, a magnetic field directed from the magnetic roller 134 toward the developing roller 136 is formed between the magnetic roller 134 and the developing roller 136 by the magnet M4 and the magnet M6. Due to the magnetic field, the magnetic brush stands up along the direction of the magnetic field from the state of being tilted on the surface 134A1 of the rotating sleeve 134A. Then, the tip of the magnetic brush comes into contact with the surface of the developing roller 136.

  Here, different voltages are applied to the magnetic roller 134 and the developing roller 136 from a power source (not shown), and a potential difference is generated between the magnetic roller 134 and the developing roller 136. The toner contained in the magnetic brush on the surface 134A1 of the rotating sleeve 134A is supplied from the magnetic brush to the surface of the developing roller 136 due to the potential difference.

  The toner supplied to the developing roller 136 is conveyed to a position P4 (see FIG. 3) facing the photosensitive drum 11 as the rotating sleeve 136A rotates in the rotation direction D7. Then, the toner is supplied to the surface of the photosensitive drum 11 by the potential difference between the voltage applied to the developing roller 136 and the surface of the photosensitive drum 11.

  The toner remaining on the surface of the developing roller 136 after passing through the facing position P4 is conveyed to the facing position P3 by the rotating sleeve 136A. And when passing the opposing position P3, it collect | recovers with the said magnetic brush on surface 134A1 of rotating sleeve 134A.

  The magnetic brush on the surface 134A1 of the rotating sleeve 134A that has passed the facing position P3 is conveyed by the magnetic force of the magnet M5, and then the region from the position facing the magnet M5 on the surface 134A1 to the position facing the magnet M1. And loses the magnetic adhesive force and peels off the surface 134A1.

  Here, in the developing unit 13, the toner may be scattered by the rotation of the first stirring member 132 and the second stirring member 133. In the developing unit 13, the toner may be scattered when the toner is supplied from the magnetic roller 134 to the developing roller 136 and when the toner is supplied from the developing roller 136 to the photosensitive drum 11. .

  The first seal member 137 and the second seal member 138 prevent the toner floating in the housing 131 from leaking outside the developing unit 13.

  As shown in FIG. 3, the first seal member 137 is provided above the opening 131 </ b> D and seals a gap formed between the opening 131 </ b> D and the photosensitive drum 11. For example, the first seal member 137 is a member having flexibility long in the left-right direction D3.

  As shown in FIG. 3, the second seal member 138 is provided below the opening 131 </ b> D, and seals a gap formed between the opening 131 </ b> D and the photosensitive drum 11. For example, like the first seal member 137, the second seal member 138 is a member that is long and flexible in the left-right direction D3.

  Incidentally, in the developing unit 13, a wall 141B (see FIG. 3) facing the surface 134A1 of the rotating sleeve 134A is provided downstream of the regulating member 135 in the rotation direction D6 of the magnetic roller 134. Here, in the developing unit 13, the toner that scatters at the facing position P3 or the like and floats inside the housing 131 enters the space S1 (see FIG. 3) between the wall 141B and the surface 134A1 of the rotating sleeve 134A. It may adhere to the regulating member 135. Further, the toner adhering to the regulating member 135 may aggregate. When the agglomerated toner moves from the regulating member 135 to the magnetic roller 134, the agglomerated toner is used for development, and there is a possibility that a problem such as a decrease in density reproducibility in a printed image may occur. On the other hand, a developing device that rotates the magnetic roller 134 in the direction opposite to the rotation direction D6 that is the rotation direction during printing and returns the toner adhering to the regulating member 135 to the second developer accommodating portion 131C is a related art. Known as.

  Here, when the process of rotating the magnetic roller 134 in the direction opposite to the rotation direction D6 is executed in the image forming apparatus 10, the use of the image forming apparatus 10 by the user is limited during the execution period of the process. . Therefore, it is desirable that the toner adhere to the regulating member 135 is suppressed as much as possible. In the developing unit 13 according to the present invention, it is possible to suppress the toner from adhering to the regulating member 135 as described below.

  Hereinafter, the configuration of the guide portion 14 will be described with reference to FIGS. Here, FIG. 4 is a cross-sectional view showing the configuration of the guide portion 14. FIG. 5 is a plan view showing the configuration of the guide portion 14.

  As shown in FIG. 3, the guide portion 14 is provided along the axial direction (left-right direction D <b> 3) of the rotation axis of the magnetic roller 134 on the downstream side of the rotation direction D <b> 6 of the magnetic roller 134 with respect to the regulating member 135. Specifically, the guide portion 14 is provided adjacent to the restriction member 135 on the upper side of the restriction member 135.

  As shown in FIG. 4, the guide part 14 includes a guide member 141, a casing 142, a vibration part 143, an elastic member 144, a contact member 145, and a magnet M <b> 7.

  The guide member 141 guides the toner floating in the developing unit 13 and the toner dropped from the surface of the developing roller 136 to the magnetic roller 134.

  For example, the guide member 141 is a sheet metal member that is long in the left-right direction D3 and is subjected to a bending process. As shown in FIG. 4, the guide member 141 is divided into an inclined wall portion 141A and the aforementioned wall portion 141B with a corner portion 141C formed by bending.

  The inclined wall portion 141 </ b> A is provided to be inclined obliquely downward toward the magnetic roller 134 on the lower side of the developing roller 136. The wall 141B is provided to extend upward on the upper side of the regulating member 135. The corner portion 141C is formed between the upper end portion of the wall portion 141B and the lower end portion of the inclined wall portion 141A.

  The casing 142 supports the guide member 141 and the contact member 145, and accommodates the vibration part 143, the elastic member 144, and the magnet M7.

  The casing 142 is long in the left-right direction D <b> 3 and is provided on the upper surface of the regulating member 135. As shown in FIG. 4, the casing 142 has a bottom surface portion 142A and a side wall portion 142B. The bottom surface portion 142A is in contact with the top surface of the regulating member 135. The side wall 142B is erected at the rear end of the bottom 142A. The side wall part 142 </ b> B forms a part of the outer surface of the housing 131. The upper end 142B1 of the side wall 142B forms the lower end of the opening 131D. For example, the casing 142 is made of resin.

  The guide member 141 is provided so as to cover the recessed space S2 (see FIG. 4) formed by the bottom surface portion 142A and the side wall portion 142B. For example, in the guide member 141, either one or both of the lower end portion of the wall portion 141B and both end portions of the wall portion 141B in the left-right direction D3 are fixed to the casing 142. The inclined wall portion 141A of the guide member 141 is supported by the casing 142 via the wall portion 141B.

  The vibration part 143 vibrates the inclined wall part 141A.

  For example, as illustrated in FIGS. 4 and 5, the vibrating portion 143 is provided on the lower surface side in the central portion of the inclined wall portion 141A. For example, the vibration unit 143 is a motor having a drive shaft 143A (see FIG. 4) extending in the left-right direction D3. The vibration part 143 is supported by a casing (not shown) fixed to the lower surface of the inclined wall part 141A. As shown in FIG. 4, a cam 143B is fixed to the drive shaft 143A. The cam 143B is a disk member having a notch.

  The elastic member 144 supports the inclined wall portion 141A so as to be movable in the vertical direction D1.

  Specifically, the elastic member 144 is provided between the lower surface of the inclined wall portion 141A and the bottom surface portion 142A of the casing 142. For example, the elastic member 144 is a coil spring in which one end portion in the longitudinal direction is fixed to the lower surface of the inclined wall portion 141A and the other end portion is fixed to the bottom surface portion 142A of the casing 142. For example, a plurality of elastic members 144 are provided in the casing 142 along the left-right direction D3. For example, as illustrated in FIG. 5, one elastic member 144 is provided on each side of the vibrating portion 143 in the left-right direction D3.

  The vibration unit 143 rotates the cam 143B in the rotation direction D8 (see FIG. 4) with electric power supplied from a power source (not shown). As a result, an uneven centrifugal force is applied to the cam 143B, and the centrifugal force is transmitted to the vibration unit 143 via the drive shaft 143A, so that the vibration unit 143 vibrates. On the other hand, the inclined wall portion 141A has an end portion on the corner portion 141C side in the front-rear direction D2 supported by the casing 142 via the wall portion 141B, and a lower surface supported by the elastic member 144. Therefore, when the vibration part 143 vibrates, the inclined wall part 141A vibrates in the vertical direction D1 together with the vibration part 143. Specifically, the inclined wall portion 141A swings in the vertical direction D1 with the corner portion 141C as a fulcrum. Thereby, the toner adhering to the upper surface of the inclined wall portion 141A is splashed up toward the magnetic roller 134 side. Therefore, the toner adhesion on the inclined wall portion 141A is suppressed.

  Here, in the inclined wall portion 141A, the toner adhesion amount may be larger at both end portions in the left-right direction D3 than at the central portion. Specifically, the movement of the toner is restricted at both end portions in the left-right direction D3 of the inclined wall portion 141A by the wall surfaces of both end portions in the left-right direction D3 of the housing 131. For this reason, the toner adhesion amount may be larger than that in the central portion.

  The contact member 145 is provided so as to be in contact with the upper surface of the inclined wall portion 141A that is vibrated by the vibration portion 143.

  For example, the contact member 145 is a sheet-like member that is long in the front-rear direction D2. As shown in FIGS. 4 and 5, the contact member 145 is disposed on the upper side of the inclined wall portion 141 </ b> A in a posture inclined downward from the inclined posture of the inclined wall portion 141 </ b> A. Specifically, the contact member 145 has an upper end supported by the upper end 142B1 of the side wall 142B of the casing 142. The lower end portion of the contact member 145 is disposed at a predetermined distance from the upper surface of the inclined wall portion 141A. The distance is a distance at which the lower end portion of the contact member 145 and the upper surface of the inclined wall portion 141A can contact when the inclined wall portion 141A is vibrated by the vibrating portion 143. For example, as shown in FIG. 5, the contact member 145 is provided corresponding to each end portion in the left-right direction D3 of the inclined wall portion 141A.

  When the inclined wall portion 141A is vibrated by the vibrating portion 143, the upper surface of the inclined wall portion 141A and the lower end portion of the contact member 145 come into contact with each other. As a result, the upper end side of the inclined wall portion 141A is flipped upward from the contact portion between the inclined wall portion 141A and the contact member 145 in the front-rear direction D2. Therefore, each of the end portions in the left-right direction D3 of the inclined wall portion 141A provided with the contact member 145 has a greater vibration width in the up-down direction D1 when vibrated by the vibration portion 143 than the center portion in the left-right direction D3. . Therefore, the effect of suppressing the adhesion of the toner to the inclined wall portion 141A due to vibration is improved at each end portion in the left-right direction D3 where the toner adheres more easily than the central portion in the left-right direction D3 in the inclined wall portion 141A.

  The guide unit 14 may not include the vibrating unit 143, the elastic member 144, and the contact member 145.

  The magnet M7, together with the magnet M3 inside the magnetic roller 134, forms a magnetic field MF1 (see FIG. 5) from the wall 141B toward the surface 134A1 in the space S1 between the surface 134A1 of the rotating sleeve 134A and the wall 141B. .

  Specifically, the magnet M7 is provided on the back surface of the wall 141B facing the surface 134A1. As shown in FIG. 5, the magnet M7 is arranged with the north pole facing the surface 134A1. Here, the N pole of the magnet M7 is an example of the first magnetic pole in the present invention. The magnet M7 is an example of the first magnetic pole member in the present invention.

  On the other hand, in the magnetic roller 134, the internal magnet M3 is arranged with the south pole facing the north pole of the magnet M7. Therefore, a magnetic field MF1 from the magnet M7 toward the magnet M3 is formed between the magnet M7 and the magnet M3 arranged with the space S1 interposed therebetween. Here, the south pole of the magnet M3 is an example of the second magnetic pole in the present invention. The magnet M3 is an example of the second magnetic pole member in the present invention. Moreover, the magnet M7 and the magnet M3 are an example of the magnetic field formation part in this invention.

  The magnetic brush formed on the surface 134A1 of the rotating sleeve 134A at the facing position P2 tilts on the surface 134A1 after passing the facing position P2. Thereafter, the magnetic brush stands on the surface 134A1 along the direction of the magnetic field MF1 by the magnetic force of the magnetic field MF1. Specifically, the magnetic brush stands on the surface 134A1 toward the wall 141B. As a result, the distance between the tip portion of the magnetic brush and the wall portion 141B is reduced, so that the toner sliding down from the inclined wall portion 141A to the space S1 is electrostatically attracted to the carrier included in the magnetic brush. It becomes possible. That is, the magnetic brush on the surface 134A1 of the rotating sleeve 134A can collect the toner that has slid down from the inclined wall portion 141A to the space S1 before dropping onto the upper surface of the regulating member 135. Accordingly, it is possible to suppress the toner from adhering to the regulating member 135.

  The magnet M7 may be disposed with the south pole facing the surface 134A1. In this case, the magnet M3 is arranged with the north pole facing the south pole of the magnet M7.

  Moreover, the magnet M3 may be arrange | positioned in the position different from the position which opposes the N pole of the magnet M7 among the downstream of the opposing position P2 in the conveyance path | route R1 in the conveyance path R1. Further, the magnetic roller 134 may not include the magnet M3. Specifically, the magnetic field MF1 may be formed between the magnet M7 and the magnet M4. In this case, the magnet M4 is another example of the second magnetic pole member in the present invention. Further, the magnetic field MF1 may be formed between the magnet M7 and a plurality of magnets in the magnetic roller 134. In this case, a plurality of magnets in the magnetic roller 134 that forms the magnetic field MF1 between the magnet M7 and the magnet M7 is another example of the magnetic field forming unit in the present invention.

  Thus, in the image forming apparatus 10, the magnetic field MF1 is formed between the magnet M7 provided on the wall 141B and the magnet M3 provided inside the magnetic roller 134. Accordingly, the magnetic brush on the surface 134A1 of the rotating sleeve 134A can be raised toward the wall 141B, and the magnetic brush can collect the toner sliding down from the inclined wall 141A to the space S1. Accordingly, it is possible to suppress the toner from adhering to the regulating member 135.

  The present invention may be applied to a developing device that does not include the developing roller 136. Specifically, the present invention may be applied to a developing device in which the magnetic roller 134 can transport the developer pumped up from the second developer accommodating portion 131 </ b> C to a position facing the photosensitive drum 11. In this case, the developing device may not include the inclined wall portion 141A. The wall 141B may be provided at a position different from the upper side of the regulating member 135.

1-4 Image forming unit 5 Intermediate transfer belt 6 Optical scanning device 7 Secondary transfer roller 8 Fixing device 9 Paper discharge tray 10 Image forming device 11 Photosensitive drum 12 Charging unit 13 Developing unit 14 Guide unit 15 Primary transfer roller 16 Cleaning device 131 Housing 132 First stirring member 133 Second stirring member 134 Magnetic roller 135 Restricting member 136 Developing roller 137 First sealing member 138 Second sealing member 141 Guide member 142 Casing 143 Vibrating portion 144 Elastic member 145 Contact member

Claims (8)

A housing containing a developer including a magnetic carrier and a non-magnetic toner;
It has an outer peripheral surface for carrying the developer, is rotatably provided inside the housing, and carries the developer on the outer peripheral surface to rotate the developer to a predetermined transport path. A transport roller for transporting along,
A regulating portion provided opposite to the outer peripheral surface across the conveyance path, and regulating a conveyance amount of the developer by the conveyance roller;
A wall portion facing the outer peripheral surface on the downstream side in the transport direction of the developer by the transport roller with respect to the regulating portion;
A first magnetic pole member having a first magnetic pole having a predetermined polarity; provided on the wall portion; wherein the first magnetic pole member is disposed toward the outer peripheral surface; and the outer peripheral surface and the wall portion A magnetic field forming part for forming a magnetic field from one of the outer peripheral surface and the wall part toward the other,
A developing device comprising: The magnetic field forming unit has a second magnetic pole having a polarity opposite to that of the first magnetic pole, and is provided inside the transport roller, and the second magnetic pole is opposed to the outer peripheral surface of the transport path and the restricting unit. Including a second magnetic pole member disposed toward a section downstream of the position,
The developing device according to claim 1. The second magnetic pole member is arranged such that the second magnetic pole faces the first magnetic pole.
The developing device according to claim 2. The wall portion is provided to extend upward on the upper side of the restriction portion,
The developing device according to claim 1. A developing roller that is provided on the upper side of the conveying roller and facing the conveying roller, and that supplies the toner supplied from the conveying roller to an image carrier provided outside the housing;
An inclined wall portion that is inclined obliquely downward toward the transport roller below the developing roller, and forms a corner with the upper end portion of the wall portion,
The developing device according to claim 4. Comprising a vibrating part for vibrating the inclined wall part,
The developing device according to claim 5. The housing has a housing portion that houses the developer,
The developing device includes a stirring member that stirs the developer in the housing portion and frictionally charges the toner and the carrier,
The transport roller transports the developer from the container.
The developing device according to claim 1.   An image forming apparatus comprising the developing device according to claim 1.

Images