JP2005345957A - Development device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a development device, superior in both developer stir performance and developer conveyance performance. <P>SOLUTION: The developing device 10a has a toner box 11, a stir member 13, a conveyance screw 14, a supply roller, a developing sleeve 16, and an exterior member 12 for accommodating them. The stir member 13 includes a shaft 131, disposed in the direction of the conveyance of supply toner and supported by the exterior member 12 at both its ends so as to freely rotate; a Mylar sheet 132 supported by the shaft 131 along one edge of it and rotates, such that the other edge slides against the internal wall face of the exterior member 12; and wedge-shaped projections formed on the internal wall face of the exterior member 12 such that the farther downstream they are, the higher they become, and the farther upstream they are, the lower they become. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device including an agitating member for agitating and charging a replenishing developer before supplying it to a developer carrying member.

  As a developing device used in the image forming apparatus, the developer replenished from the developer replenishing container is frictionally charged to a predetermined charge amount (saturated charge amount) while stirring and transporting the developer replenished in the developing tank, There is a type in which an electrostatic latent image is developed by supplying a charged developer onto a photosensitive drum by a developing roller.

  In such a developing device, the newly replenished developer was previously in the developing tank while being stirred and transported by the stirring screw that rotates while sliding the tip portion against the inner wall of the developing tank in the developing tank. The developer is uniformly stirred and charged by frictional force. However, in order to prevent the stirrability from deteriorating due to the recent downsizing of developing devices and higher printing speeds, the replenished developer is not supplied directly to the developing tank where the developing roller is placed, but for premixing. There is a technique for providing a developer tank having a developing roller after pre-stirring the newly replenished developer in the premix space.

  In such a technique for providing a space for premixing, a stirring member is disposed immediately below the developer supply container, and the developer supplied from the developer supply container is unwound by the stirring member in the next process. It is sent to the conveying screw. The replenishment developer sent to the transport screw is transported toward the one end in the axial direction of the transport screw by the transport screw, and is replenished to the developing tank from an opening provided at one end in the axial direction of the transport screw. .

  In the developing device configured as described above, the stirring performance of the stirring member with respect to the replenished developer is a factor that affects the degree of mixing of the developer. When the stirring is insufficient, the replenished developer seems to aggregate. Resulting in generation of uncharged developer. In the case of over-stirring, the developer is pulverized by the frictional force between the stirring member and the inner wall of the exterior member, the particle size is reduced, and the developer is scattered in the machine.

As a technique for solving such problems, in order to achieve both the stirring performance of the stirring member and the transport performance of transporting the developer, the stirring member is tapered to change the contact distance with the inner wall surface of the exterior member. The structure to make is proposed (for example, refer patent document 1).
JP-A-7-104572

  However, in the conventional configuration described above, the developer remains on the inner wall surface of the exterior member in the portion pursuing the stirring performance, and the developer is damaged in the portion pursuing the transport performance. It is hard to say that this technology satisfies the requirements.

  An object of the present invention is to provide a developing device that is excellent in both stirring performance and conveyance performance for a developer.

  The developing device of the present invention is configured as follows in order to solve the above-described problems.

  (1) a developer carrier disposed in a developing tank so as to face an image carrier carrying an electrostatic latent image and supplying a developer for developing the electrostatic latent image onto the image carrier; A developer replenishing port through which the replenishing developer supplied to the developing tank passes, a conveying member that conveys the replenishing developer toward the developer replenishing port, and conveyance of the developer by the conveying member An agitation member that agitates the replenishment developer in a direction parallel to the direction and supplies the replenishment developer to the conveyance member; a developer tank that houses the developer carrier; and the conveyance member And an exterior member that forms a space for premix containing the stirring member, and the developer replenishing port is provided in a part of the transport direction of the developer by the transport member, Communication between the space and the developer tank The stirring member includes a rotating shaft disposed along a transport direction of the replenishment developer, an elastic member having one end supported by the rotating shaft and the other end slidingly contacting the inner wall surface of the exterior member, A wedge-shaped protrusion provided on an inner wall surface of the exterior member and higher with respect to the inner wall surface toward one side in the transport direction and lower toward the other side.

  In this configuration, the stirring member agitates the newly supplied developer by the rotating elastic member, so that the developer is released and charged. The elastic member rotates while slidingly contacting a wedge-shaped protrusion provided on the inner wall surface of the exterior member, thereby conveying the developer in a direction in which the protrusion becomes higher than the inner wall surface. The developer brought to the downstream side in the transport direction by the stirring member is supplied to the transport member, and the transport member transports the developer to a developer supply port provided in a part of the transport direction of the developer by the transport member. The developer passes through the developer supply port and is supplied to the developing tank, and is supplied onto the image carrier by the developer carrier. In this way, the newly replenished developer is premixed and charged by the stirring member, then supplied to the conveying member, and then supplied to the developing tank through the developer replenishing port.

  (2) The protrusion is characterized in that it is higher on the downstream side in the transport direction of the developer by the transport member with respect to the inner wall surface and lower on the upstream side.

  In this configuration, the newly replenished developer is transported by the stirring member toward the downstream side in the developer transport direction by the transport member, that is, toward the side closer to the developer supply port, and gathered downstream. To the conveying member side.

  (3) The protrusion is characterized in that it is lower on the upstream side in the rotation direction of the elastic member and higher on the downstream side with respect to the inner wall surface.

  In this configuration, as the elastic member rotates, the bending of the elastic member due to the sliding contact with the protrusion gradually increases, and the developer conveyance speed toward the downstream side in the conveyance direction gradually increases.

  (4) A plurality of the protrusions are provided along the direction of the rotation axis, and the height of the highest part of each protrusion is as high as the protrusion on the downstream side in the developer conveyance direction by the stirring member. It is characterized by being higher and lower on the upstream projection.

  In this configuration, since the protrusion disposed on the downstream side in the developer conveyance direction by the stirring member is formed higher with respect to the inner wall surface of the exterior member, the developer conveyance speed is higher on the downstream side in the conveyance direction. Become.

  (5) The elastic member may be divided at a position corresponding to the highest portion of each protrusion.

  When a plurality of protrusions are provided and the elastic member is not divided, the elastic member floats at the downstream portion of the protrusion, and the elastic member does not slide on the lower protrusion particularly when the height of each protrusion is different. However, in this configuration, the elastic member is divided at a position corresponding to the highest portion of each protrusion, so that the elastic member is prevented from being lifted with respect to each protrusion and the inner wall surface of the exterior member. Rotates while slidingly contacting each protrusion and the inner wall surface of the exterior member.

  (6) The protrusion is formed integrally with the exterior member.

  In this configuration, the protrusion is integrally formed with the exterior member.

  (7) The protrusion is detachable from an inner wall surface of the exterior member.

  In this configuration, an appropriately sized protrusion having an appropriate height and an appropriate gradient with respect to the inner wall surface of the exterior member is selected according to the flowability and particle diameter of the developer, and the appropriate position. It is attached to.

  According to the present invention, the following effects can be obtained.

  (1) Since the developer is stirred by the elastic member, the developer can be sufficiently stirred and charged while suppressing pulverization of the developer by the frictional force between the elastic member and the inner wall surface of the exterior member. Further, the developer can be transported in a predetermined direction by rotating while the elastic member is in sliding contact with the wedge-shaped protrusion. Furthermore, since the developer is brought to one side by the stirring member, the developer can be easily supplied from the stirring member to the conveying member even when the amount of the developer is small.

  (2) Since the developer is gathered on the downstream side in the transport direction of the developer by the transport member and then supplied to the transport member side, the developer replenishing port can be passed as soon as it is supplied to the transport member. The developer can be supplied to the developer carrying member.

  (3) The stirring performance for the developer can be improved by changing the transport speed of the developer along with the rotation of the elastic member.

  (4) Since the developer conveyance speed is higher toward the downstream side in the conveyance direction, the developer is not clogged during conveyance, and the developer can be conveyed smoothly. That is, the conveyance performance for the developer can be improved.

  (5) Since the elastic member rotates while being in sliding contact with each protrusion and the inner wall surface of the exterior member, it is possible to prevent deterioration of the stirring performance and the transport performance with respect to the developer.

  (6) Since the protrusion can be integrally formed with the exterior member, the mold can be integrated, and workability can be improved and the cost can be reduced.

  (7) Since the setting of the protrusion can be changed according to the situation such as the type of developer, high stirring performance and conveyance performance can be exhibited regardless of the change in the situation.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus including a developing device according to an embodiment of the present invention. An image forming apparatus 1 including developing devices 10a to 10d according to this embodiment includes a double-sided automatic document feeder (RADF) 112, a document table 111, an image reading unit 110, an image forming unit 210, and a paper feed. A mechanism 211 is provided.

  The double-sided automatic document feeder 112 is arranged so that the upper surface of the document table 111 can be opened and closed. The double-sided automatic document feeder 112 first transports the document to a predetermined position on the document table 111 so that one side of the document faces the image reading unit 110, and after the image reading on this one side is completed. Then, the document is reversed and conveyed to a predetermined position on the document table 111 so that the other side of the document faces the image reading unit 110. The double-sided automatic document feeder 112 discharges the original after the double-sided image reading for one original is completed, and executes a double-sided conveyance operation for the next original. The above document transport and front / back reversing operations are controlled in relation to the overall operation of the image forming apparatus 1.

  The image reading unit 110 is disposed below the document table 111 and reads an image of the document conveyed on the document table 111 by the double-sided automatic document feeder 112. The image reading unit 110 includes a first scanning unit 113 and a second scanning unit 114 that reciprocate along the lower surface of the document table 111, an optical lens 115, and a CCD line sensor 116 that is a photoelectric conversion element. .

  The first scanning unit 114 has an exposure lamp that exposes the surface of the image of the document, and a first mirror that deflects the reflected light image from the document in a predetermined direction at a predetermined scanning speed. It reciprocates parallel to the document table 111. The second scanning unit 114 includes a second mirror and a third mirror that further deflect the reflected light image from the original deflected by the first mirror of the first scanning unit 113 in a predetermined direction. The first scanning unit 113 is reciprocated in parallel with the document table 111 while maintaining a constant speed relationship.

  The optical lens 115 reduces the reflected light image from the original deflected by the third mirror of the second scanning unit, and forms the reduced light image at a predetermined position on the CCD line sensor 116.

  The CCD line sensor 116 sequentially photoelectrically converts the formed light image and outputs it as an electrical signal. The CCD line sensor 116 is a three-line color CCD that can read a black and white image or a color image and output line data separated into R (red), G (green), and B (blue) color components. . The image data converted into an electrical signal by the CCD line sensor 116 is further transferred to the image processing unit and subjected to predetermined image processing.

  An image forming unit 210 and a paper feed mechanism 211 are disposed below the image reading unit 110. The paper feed mechanism 211 is disposed below the image forming unit 210, separates the paper P stacked and stored in the paper tray one by one, and supplies the paper P toward the image forming unit 210. The sheets P supplied separately one by one are conveyed to the image forming unit 210 with timing controlled by a pair of registration rollers 212 arranged in front of the image forming unit 210. Further, the sheet P on which an image is formed on one side is re-conveyed to the image forming unit 210 in accordance with the image forming process of the image forming unit 210 as necessary.

  A transfer conveyance belt mechanism 213 is disposed between the image forming unit 210 and the paper feed mechanism 211. The transfer / conveying belt mechanism 213 conveys the sheet P by electrostatically adsorbing the sheet P onto the transfer / conveying belt 216 stretched substantially in parallel between the driving roller 214 and the driven roller 215. In addition, a pattern image detection unit is provided in the vicinity of the lower side of the transfer conveyance belt 216.

  Further, a fixing device 217 for fixing the toner image transferred onto the paper P onto the paper P is disposed on the downstream side of the transfer conveyance belt mechanism 213 in the paper P conveyance direction. The paper P that has passed between the pair of fixing rollers of the fixing device 217 passes through a switching gate 218 that switches the conveyance direction of the paper P, and then onto the paper discharge tray 220 attached to the outer wall of the image forming apparatus 1 by the discharge roller 219. Discharged.

  The switching gate 218 selectively switches the conveyance path of the paper P after image fixing to a path for discharging the paper P to the discharge tray 220 and a path for resupplying the paper P toward the image forming unit 210. . The sheet P transported again toward the image forming unit 210 by the switching gate 218 is reversed and then supplied to the image forming unit 210 via the switchback transport path 221.

  The image forming unit 210 is close to the upper surface of the transfer conveyance belt 216, so that the first image forming station Pa, the second image forming station Pb, the third image forming station Pc, and the fourth image forming station Pd. The image forming stations Pa to pd are arranged in this order from the upstream side in the transport direction of the paper P.

  The transfer conveying belt 216 is frictionally driven by the driving roller 214 in the direction indicated by the arrow Z in FIG. 1 and carries the paper P fed by the paper feeding mechanism 211, and sequentially feeds the paper P to the image forming stations Pa to Pd. Transport.

  Each of the image forming stations Pa to Pd has substantially the same configuration. Each of the image forming stations Pa to Pd includes photosensitive drums 222a, 222b, 222c, and 222d, which are image carriers that are rotationally driven in the direction of arrow F shown in FIG.

  Around each of the photosensitive drums 222a to 222d, there are chargers 223a, 223b, 223c, and 223d for uniformly charging the photosensitive drums 222a to 222d, and electrostatic latent images formed on the photosensitive drums 222a to 222d. Development devices 10a, 10b, 10c, and 10d that develop the images into toner images, and transfer dischargers 225a, 225b, 225c, and 225d that transfer the toner images on the photosensitive drums 222a to 222d to the paper P, Cleaning devices 226a, 226b, 226c, and 226d for removing the toner that is a developer remaining on the photosensitive drums 222a to 222d are arranged in this order along the rotation direction of the photosensitive drums 222a to 222d.

  Further, laser beam scanner units 227a, 227b, 227c, and 227d are provided above the photosensitive drums 222a to 222d, respectively. The laser beam scanner units 227a to 227d include a semiconductor laser element (not shown) that emits dot light modulated according to image data, and a polygon mirror for deflecting the laser beam from the semiconductor laser element in the main scanning direction. 240, an fθ lens 241 and mirrors 242 and 243 for forming an image of the laser beam deflected by the polygon mirror 240 on the surface of the photosensitive drums 222a to 222d.

  The laser beam scanner unit 227a has a pixel signal corresponding to the black component image of the color original image, the laser beam scanner unit 227b has a pixel signal corresponding to the cyan component image of the color original image, and the laser beam scanner unit 227c has the pixel signal. A pixel signal corresponding to the magenta color component image of the color original image is input, and a pixel signal corresponding to the yellow color component image of the color original image is input to the laser beam scanner unit 227d.

  As a result, electrostatic latent images corresponding to the color-converted image data are formed on the respective photosensitive drums 222a to 222d. The developing device 10a contains black toner, the developing device 10b contains cyan toner, the developing device 10c contains magenta toner, and the developing device 10d contains yellow toner. The electrostatic latent images on the body drums 222a to 222d are developed with these color toners. As a result, the color-converted image data is reproduced as a toner image of each color.

  Further, a sheet suction charger 228 is provided between the first image forming station Pa and the paper feed mechanism 211, and the suction charger 228 charges the surface of the transfer conveyance belt 216, and the paper feed mechanism 211. The sheet P supplied from the first image forming station P is conveyed without deviation from the first image forming station Pa to the fourth image forming station Pd in a state where the sheet P is securely adsorbed onto the transfer conveying belt 216.

  On the other hand, a static eliminator 229 is provided substantially directly above the drive roller 214 between the fourth image station Pd and the fixing device 217. An AC voltage is applied to the static eliminator 229 for separating the sheet P electrostatically attracted to the transport belt 216 from the transfer transport belt 216.

  In the image forming apparatus 1 configured as described above, for example, cut sheet-shaped paper is used as the paper P. When the paper P is fed from the paper feed cassette and supplied into the guide of the paper feed conveyance path of the paper feed mechanism 211, the leading end portion of the paper P is detected by a sensor (not shown) and output from this sensor. Based on the detected signal, the pair of registration rollers 212 are temporarily stopped.

  Then, the paper P is fed onto the transfer conveyance belt 216 rotating in the direction of the arrow Z in FIG. 1 in time with the image forming stations Pa to Pd. At this time, the transfer conveyance belt 216 is charged by the adsorption charger 228 as described above, so that the paper P is stably conveyed while passing through the image forming stations Pa to Pd. The

  In each of the image forming stations Pa to Pd, each color toner image is formed and superimposed on the paper P that is electrostatically attracted and conveyed by the transfer conveyance belt 216. When the transfer of the toner image by the fourth image station Pd is completed, the paper P is sequentially peeled off from the transfer conveyance belt 216 by the static eliminator 229 from the leading end portion thereof and guided to the fixing device 217. The paper P on which the toner image is fixed is discharged onto a paper discharge tray 220 from a paper discharge port (not shown).

  In the above-described embodiment, the configuration in which the laser beam scanner units 227a to 227d perform light writing on the photosensitive drums 222a to 222d by scanning and exposing the laser beams has been described. However, the laser beam scanner units 227a to 227d are described. Instead, a writing optical system (LED head) including a light emitting diode array and an imaging lens array may be used. The LED head is smaller than the laser beam scanner units 227a to 227d, and is silent because there are no movable parts. Therefore, it can be suitably used in an image forming apparatus such as a tandem digital color copying machine that requires a plurality of optical writing units.

  FIG. 2 is a cross-sectional view showing a schematic configuration of the developing device 10a. Although only the developing device 10a will be described here, the other developing devices 10b to 10d are configured substantially in the same manner as the developing device 10a except for the toner to be used, and have the same effects.

  The developing device 10a includes a toner box 11 that stores toner for replenishment, an exterior member 12, a stirring member 13, a conveying screw 14 that is a conveying member, a supply roller 15, and a developing sleeve 16 that is a developer carrier. The stirring member 13, the conveying screw 14, the supply roller 15, and the developing sleeve 16 are accommodated in the exterior member 12. The interior of the developing device 10a excluding the toner box 11 is divided into a premix space in which the agitating member 13 and the conveying screw 14 are arranged by the exterior member 12, and a developing tank in which the supply roller 15 and the developing sleeve 16 are arranged. Broadly divided. The premix space and the developing tank are communicated with each other by a toner replenishing port 17 which is a developer replenishing port of the present invention.

  The toner newly replenished from the toner box 11 is unraveled and charged by being agitated in advance in the premix space, and then supplied to the developing tank through the toner replenishing port 17. The toner supplied from the premix space to the developing tank is already charged to a predetermined potential, mixed with the toner previously in the developing tank by the supply roller 15 and supplied to the developing sleeve 16. The developing sleeve 16 is disposed so as to face the photosensitive drum 222a. The developing sleeve 16 carries toner and supplies it to the photosensitive drum 222a, and develops the electrostatic latent image on the photosensitive drum 222a into a toner image.

  The region where the stirring member 13 is disposed and the region where the conveying screw 14 is disposed are partitioned to a predetermined height by the exterior member 12 and are each surrounded by the inner wall surface of the exterior member 12 having a substantially semicircular cross section. In this embodiment, the Mylar sheet 132 (see FIG. 3) of the stirring member 13 is driven to rotate counterclockwise, and the conveying screw 14 is driven to rotate clockwise.

  FIG. 3 is a cross-sectional view taken along line XX shown in FIG. The conveying screw 14 has a shaft 141 that is rotatably supported at both ends by the exterior member 12, and rotates the shaft 141 as a rotation axis by a driving force supplied from a driving source, whereby the toner is moved upward in FIG. 3. Transport to. The toner replenishing port 17 is provided on the downstream side in the toner transport direction by the transport screw 14.

  The stirring member 13 is provided on a shaft 131 that is a rotating shaft that is rotatably supported at both ends by the exterior member 12, a mylar sheet 132 that is an elastic member supported at one end by the shaft 131, and an inner wall surface of the exterior member 12. It includes a plurality of protrusions 133 provided. The shaft 131 of the stirring member 13 and the shaft 141 of the conveying screw 14 are disposed substantially in parallel. When the shaft 131 is rotated by the driving force supplied from the driving source, the mylar sheet 132 rotates while the other end is in sliding contact with the inner wall surface of the exterior member 12.

  A plurality of protrusions 133 are arranged in a direction along the shaft 131, and each protrusion 133 is formed in a wedge shape so as to be higher toward the upper side in FIG. 3 and lower toward the lower side than the inner wall surface of the exterior member 12. (See FIG. 4A and FIG. 4B.) In addition, when comparing the height of the most downstream portion of each projection 133, that is, the highest portion with respect to the inner wall surface of the exterior member 12, the projection 133 positioned higher in FIG. The portion 133 is formed as low as possible. In this embodiment, each protrusion 133 is formed integrally with the exterior member 12.

  The mylar sheet 132 is provided with a cut at a position corresponding to the highest portion of each protrusion 133 and is divided into a plurality of parts in the direction along the shaft 131.

  4A is a cross-sectional view taken along the line AA shown in FIG. 3, FIG. 4B is a cross-sectional view taken along the line BB shown in FIG. 3, and FIG. 4 is a cross-sectional view taken along the line CC shown in FIG. 3, and FIG. 4D is a cross-sectional view taken along the line DD shown in FIG.

  As shown in FIG. 4A and FIG. 4B, each protrusion 133 is lower with respect to the inner wall surface of the exterior member 12 toward the upstream side in the rotational direction of the Mylar sheet 132 and higher toward the downstream side. It is formed.

  The Mylar sheet 132 rotates while the front end portion is slidably in contact with the inner wall surface of the exterior member 12 and each protrusion 133, and the Mylar sheet 132 is in contact with the higher portion of the protrusion 133 with respect to the inner wall surface of the exterior member 12. The curvature of the sheet 132 is increased, and the toner is conveyed toward the direction in which the protrusion 133 is formed high, that is, upward in FIG. 3, and is collected near the wall surface of the exterior member 12 on the most downstream side in the conveyance direction. The collected toner is supplied to the conveyance screw 14 side by overcoming the partition with the conveyance screw 14 by the exterior member 12 by the rotational force of the Mylar sheet 132. Further, a part of the toner is transported to the transport screw 14 side over the partition with the transport screw 14 by the exterior member 12 before being transported to the most downstream side in the transport direction. That is, according to the stirring member 13, the toner is simultaneously transported in two directions, a direction parallel to the shaft 131 and a direction perpendicular to the shaft 131.

  Further, since the toner is gathered in one direction by the stirring member 13, even when the amount of toner in the region where the stirring member 13 is small, the conveying screw 14 is disposed from the region where the stirring member 13 is disposed. Toner is easily supplied to the area. In this embodiment, the toner is gathered in the downstream direction in the toner conveyance direction, that is, in the direction approaching the toner supply port 17 and supplied to the conveyance screw 14 side. In addition, the toner is smoothly conveyed to the toner supply port 17. Accordingly, the toner is quickly supplied to the developing sleeve 16.

  Further, when the heights of the highest portions of the respective protrusions 133 are compared, the protrusions 133 positioned on the downstream side in the toner transport direction are formed higher and the protrusions 133 positioned on the upstream side are formed lower. The higher the toner conveyance speed. Therefore, the toner is smoothly conveyed without being clogged during the conveyance by the stirring member 13.

  Further, each protrusion 133 is formed so as to be lower on the upstream side in the rotation direction of the mylar sheet 132 with respect to the inner wall surface of the exterior member 12 and higher on the downstream side. The toner conveyance speed increases. Since the toner conveyance speed changes with the rotation of the Mylar sheet, the stirring performance for the toner is improved.

  Further, since the mylar sheet 132 is divided at a position corresponding to the highest portion of each protrusion 133, the mylar sheet 132 is slid without being lifted with respect to each of the plurality of protrusions 133 having different heights and the inner wall surface of the exterior member 12. Rotates while touching. Therefore, the toner is reliably agitated and conveyed at each part in the direction along the shaft 131.

  Further, since the toner is agitated by the elastic Mylar sheet 132, the toner is prevented from being pulverized by the frictional force between the Mylar sheet 132 and the inner wall surface of the exterior member 12.

  Therefore, the developing device 10a can exhibit excellent stirring performance, that is, charging performance and transport performance with respect to the toner. Further, since the projection 133 is formed integrally with the exterior member 12, the molding die for the projection 133 and the molding die for the exterior member 12 can be integrated, thereby improving workability and reducing costs. be able to.

  The protrusion 133 can also be formed detachably with respect to the inner wall surface of the exterior member 12. In this case, the position where the protrusion 133 is mounted, the height of the highest portion of each protrusion 133, and the slope of the inclined surface of each protrusion 133 according to the flow performance and particle diameter of the toner used in the developing device 10a. And the size of each protrusion 133 can be selected as appropriate. This makes it possible to adjust the stirring performance and conveyance performance for the toner in each section.

  Further, in the above-described embodiment, the protrusion 133 is formed in a wedge shape that is higher in the downstream direction of the toner conveyance direction by the conveyance screw 14, that is, in the direction closer to the toner supply port 17, and lower in the upstream direction, that is, in the direction away from the toner supply port 17. However, the wedge shape may be lower in the reverse direction, that is, the downstream side in the toner conveyance direction by the conveyance screw 14, that is, the direction closer to the toner supply port 17, and the higher the upstream side, that is, the direction away from the toner supply port 17. Also with this configuration, the toner is transported and collected in one direction along the shaft 131 by the stirring member 13 and supplied to the transport screw 14 side. In this case, the height of the highest portion of the plurality of protrusions 133 is preferably as low as the protrusion 133 near the toner supply port 17 and as high as the protrusion 133 far from the toner supply port 17.

  Further, in FIG. 3 and FIG. 4, the protrusion 133 is provided in the rotation direction of the mylar sheet 132 from just below the shaft 131 to the partition portion with the conveying screw 14 by the exterior member 12, but is not limited thereto. It can be provided from any position to any position.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus including a developing device according to an embodiment of the present invention. It is sectional drawing which shows the schematic structure of a developing device. It is sectional drawing in the XX line shown in FIG. (A) is sectional drawing in the AA line shown in FIG. 3, (b) is sectional drawing in the BB line shown in FIG. 3, (c) is CC in FIG. It is sectional drawing in a line, (d) is sectional drawing in the DD line | wire shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10a-10d Developing apparatus 11 Toner box 12 Exterior member 13 Stirring member 14 Conveying screw 16 Developing sleeve 17 Toner supply port 131 Shaft 132 Mylar sheet 133 Protruding part 222a-222d Photosensitive drum

Claims (7)

A developer carrier disposed in a developing tank so as to face an image carrier carrying an electrostatic latent image and supplying a developer for developing the electrostatic latent image onto the image carrier;
A developer replenishing port through which replenishment developer supplied to the developer tank passes;
A transport member for transporting the replenishment developer toward the developer replenishment port;
An agitation member that agitates the developer for replenishment in a direction parallel to the direction of conveyance of the developer by the conveyance member and supplies the developer for replenishment to the conveyance member;
An exterior member that forms a developer tank that accommodates the developer carrier and a premix space that accommodates the transport member and the agitation member;
The developer replenishment port is provided in a part of the transport direction of the developer by the transport member, and communicates the premix space and the developer tank,
The stirring member includes a rotation shaft disposed along a transport direction of the replenishment developer,
An elastic member having one end supported by the rotating shaft and the other end slidingly contacting the inner wall surface of the exterior member;
And a wedge-shaped protrusion provided on an inner wall surface of the exterior member and higher on one side in the transport direction than the inner wall surface and lower on the other side.   2. The developing device according to claim 1, wherein the protrusion is higher toward a downstream side in the transport direction of the developer by the transport member with respect to the inner wall surface and lower toward an upstream side.   3. The developing device according to claim 1, wherein the protruding portion is lower toward the upstream side in the rotation direction of the elastic member and higher toward the downstream side with respect to the inner wall surface. A plurality of the protrusions are provided along the direction of the rotation axis,
The height of the highest portion of each of the protrusions is higher in the downstream protrusion in the developer conveyance direction by the stirring member and lower in the upstream protrusion. The developing device according to any one of the above.   The developing device according to claim 4, wherein the elastic member is divided at a position corresponding to the highest portion of each protrusion.   The developing device according to claim 1, wherein the protrusion is formed integrally with the exterior member.   The developing device according to claim 1, wherein the protrusion is detachable from an inner wall surface of the exterior member.

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