JP2011248169A - Developing device and image forming apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device which can effectively prevent toner from accumulating near a blade in a casing, and to provide an image forming apparatus having the device.SOLUTION: In a developing container 20 of developing devices 3a-3d, a recessed part 35b is formed on an internal surface 35a of a scraper unit 35 which is provided between a bristle cutting blade 33 and a region in which a developing roller 31 faces photoreceptor drums 1a-1d. The recessed part 35b includes a toner dispersion member 40 which has a large number of protrusions 40b for dispersion composed of an elastic material on an outer peripheral surface of a rotation shaft 40a.

Description

  The present invention relates to a developing device that supplies a developer to an image carrier and an electrophotographic image forming apparatus including the developing device.

  An electrophotographic image forming apparatus irradiates the peripheral surface of an image carrier (photosensitive drum) with light based on image information read from an original image or image information transmitted from an external device such as a computer. An electrostatic latent image is formed, toner is supplied from the developing device to the electrostatic latent image to form a toner image, and then the toner image is transferred to a sheet. The paper after the transfer process is subjected to a toner image fixing process and then discharged to the outside.

  By the way, in recent years, in the image forming apparatus, the configuration of the apparatus becomes complicated as color printing and high-speed processing progress, and the toner stirring member in the developing device is forced to rotate at high speed in order to cope with high-speed processing. As a result, the inside of the developing device easily becomes a positive pressure higher than the atmospheric pressure. When the pressure inside the developing device becomes positive, when toner is supplied from the developing device to the photosensitive drum, a part of the toner becomes floating toner and is discharged from the opening facing the photosensitive drum, and the image forming apparatus The inside of the apparatus main body is contaminated and necessary toner is hardly supplied to the electrostatic latent image. As a result, troubles such as a so-called toner drop phenomenon that the toner is not supplied to the portion where the toner is to be laminated on the peripheral surface of the photosensitive drum are likely to occur.

  In order to solve such a problem, Patent Document 1 proposes a developing device improved so as to prevent toner leakage. In this developing device, a casing is internally provided with a stirring roller and a developing roller that is disposed downstream of the stirring roller and supplies toner to the peripheral surface of the photosensitive drum. The stirring member is disposed slightly above the bottom plate of the casing, and the developing roller is disposed obliquely above the stirring member.

  A partition plate (a sink plate in Patent Document 1) that guides the toner to flow toward the peripheral surface of the developing roller is provided obliquely above the stirring member. Due to the presence of the partition plate, the inside of the casing is divided into upper and lower parts, and the toner above the partition plate is supplied to the space below the partition plate through the gap between the lower end edge of the partition plate and the bottom plate of the casing. Is done. The toner supplied here is continuously pumped up to the peripheral surface of the developing roller by the driving rotation of the stirring roller, and is supplied from the peripheral surface of the developing roller to the peripheral surface of the photosensitive drum.

  In the above developing device, a vent hole is formed in the partition plate, and the air in the space below the partition plate, which has become positive pressure by the rotation of the stirring roller, is extracted to the space above the partition plate through the vent hole. The pressure in the space below the partition plate can be released. With this configuration, the pressure in the space in which the stirring roller is provided is reduced, so that air containing floating toner is not discharged to the outside from the toner discharge port, and as a result, floating from the toner discharge port is prevented. Toner leakage can be prevented.

JP 10-48948 A

  By the way, in the developing device described in Patent Document 1, air containing floating toner existing in the space below the partition plate in the casing passes through the vent hole formed in the partition plate. The distribution direction is substantially perpendicular to the conveying direction of the toner fed to the photosensitive drum by the rotation of the developing roller.

  Therefore, the strength of the airflow directed toward the air hole is often not strong enough to cancel out the air flow that is going to accompany the rotation of the developing roller. As a result, the rotation of the developing roller makes it easy for air containing floating toner to flow toward the peripheral surface of the photosensitive drum, and the toner leaks from the opening of the casing facing the peripheral surface of the photosensitive drum. There is a point.

  Also, in the developing device, scattered toner may accumulate around the pan blade, and if the accumulated toner aggregates and adheres to the developing roller, the toner may fall and cause image defects. There is also.

  Therefore, for example, as shown in FIG. 20, it is conceivable to provide an air inflow hole for taking in air from the outside of the developing device in the wall portion of the developing device facing the developing roller of the developing container. FIG. 20 is a schematic cross-sectional side view showing a configuration around the developing device provided with the air inflow hole. As shown in FIG. 20, the developing container 20 of the developing device 3a is provided with a stirring and conveying screw 25a, a supply and conveying screw 25b, a magnetic roller 30, and a developing roller 31.

  The developer containing the toner and the carrier stirred and conveyed by the stirring and conveying screw 25a is supplied to the magnetic roller 30 that rotates clockwise in the drawing by the supply and conveying screw 25b, and forms a magnetic brush on the magnetic roller 30. Of the magnetic brush on the magnetic roller 30, only the toner is carried on the developing roller 31 that rotates clockwise in the figure, and the toner is supplied from the developing roller 31 to the photosensitive drum 1a.

  In the space to the left of the magnetic roller 30 and the developing roller 31 and above the ear cutting blade 33, an air flow as indicated by broken lines is generated by the clockwise rotation of the magnetic roller 30 and the developing roller 31, respectively. The two air flows indicated by the broken lines merge, and as a whole, an upward air flow is generated as indicated by the solid line. Therefore, even when the floating toner is present in the vicinity of the ear cutting blade 33, it is possible to prevent the toner from accumulating on the ear cutting blade 33 by placing the floating toner on this air flow.

  Accordingly, in the developing container 20, a scraper unit 35 that protrudes inside the developing container 20 and holds the ear cutting blade 33 is provided above the ear cutting blade 33 in the drawing, and the two air inflow holes 35d are provided in the scraper unit 35. As a result, the air flow that flows in from the outside to the inside of the developing container 20 flows into the vicinity of the ear cutting blade 33 that has become a negative pressure due to the generation of the air flow indicated by the solid line.

  By the flow of the air flow, it becomes possible to reduce the pressure of the portion that has become positive pressure due to the rotation of the magnetic roller 30 and the developing roller 31. Further, the air flow that flows in joins the upward air flow, so that the floating toner in the vicinity of the ear cutting blade 33 is placed on the upward air flow to prevent toner accumulation on the ear cutting blade 33. be able to.

  However, even when the air inflow hole is provided in this way, if the apparatus main body is increased in speed and the toner floating amount is large, the floating toner is sufficiently added to the air flow generated by the rotation of the magnetic roller and the developing roller. It becomes difficult to mount the toner, and it is difficult to sufficiently prevent toner accumulation.

  In view of the above problems, an object of the present invention is to provide a developing device capable of effectively preventing toner accumulation around a blade in a casing and an image forming apparatus including the developing device.

  In order to achieve the above object, the present invention provides a developer carrying member that is disposed to face an image carrier on which an electrostatic latent image is formed and supplies the developer to the image carrier in a region facing the image carrier. A developing device comprising: a body; a blade that regulates the amount of developer carried on the developer carrying body; and a casing that houses the blade and the developer carrying body, wherein the casing includes the blade And a wall portion facing the developer carrying member, and a groove-like recess is formed in the wall portion over substantially the entire longitudinal direction. Is characterized in that a toner dispersion member comprising a rotation shaft and a number of dispersion protrusions formed on the outer peripheral surface of the rotation shaft is arranged so that the dispersion protrusions are in contact with the inner surface of the recess. It is said.

  According to the present invention, in the developing device configured as described above, the wall portion has a downward slope from the facing region side toward the blade side, and the toner dispersion member has a downward slope along the inner surface of the recess. It is characterized by rotating in the direction.

  According to the present invention, in the developing device configured as described above, an air inflow hole through which external air flows into the developing container is formed between the concave portion of the wall and the blade, and the upper end of the developing container is formed. An air outflow hole for allowing the air inside the developing container to flow out is formed.

  According to the present invention, in the developing device configured as described above, the dispersion protrusion is formed by winding a flexible film member having a large number of cuts on one side around the outer peripheral surface of the rotating shaft with the cuts facing outward. It is characterized by being formed.

  According to the present invention, in the developing device configured as described above, the film member has a ribbon shape in which a large number of cuts are formed along one side in the longitudinal direction, and the dispersion protrusion has a cut in the film member. It is characterized in that it is formed by spirally winding along the outer peripheral surface of the rotating shaft with the non-side as a fixed part.

  According to the present invention, in the developing device configured as described above, the cut formed in the film member is inclined by a predetermined angle from a direction perpendicular to the longitudinal direction.

  According to the present invention, in the developing device configured as described above, the engagement protrusions are formed at both ends of the film member, and the engagement is provided with slits into which the engagement protrusions are inserted at two locations on the outer peripheral surface of the rotating shaft. A part is formed.

  According to the present invention, in the developing device configured as described above, a hook portion wider than a slit of the engaging portion is formed at a tip of the engaging protrusion.

  According to the present invention, in the developing device configured as described above, a spiral shape or a spiral pattern is formed on the outer peripheral surface of the rotation shaft in accordance with the winding position of the film member.

  According to the present invention, in the developing device configured as described above, the film member includes a first inclined portion that is inclined toward both end portions of the film member at an end edge in a longitudinal direction of the fixed portion. It is characterized by.

  According to the present invention, in the developing device configured as described above, the edge of the portion of the film member in which the cut is formed is on the end side in the direction in which the tip of the dispersion projection faces when wound around the rotation shaft. The second inclined part which inclines toward the edge part of the said film member is formed.

  According to the present invention, in the developing device configured as described above, the film member has a fan shape in which a large number of cuts are formed from an outer peripheral edge toward an inner peripheral edge, and the dispersion protrusion is formed by a cut in the film member. It is characterized in that it is formed by winding a plurality of conical shapes around the rotating shaft at a predetermined pitch with the inner peripheral side not being fixed as a fixed portion.

  According to the present invention, in the developing device configured as described above, the dispersion protrusion is fixed to be inclined with respect to the axial direction of the rotation shaft, and a projection length of the dispersion protrusion onto the rotation shaft is the rotation axis direction. It is characterized by being larger than the pitch of the dispersing projections in FIG.

  In the developing device having the above-described configuration, the film member is fixed to the rotating shaft using a tape-like attachment member having an adhesive layer or an adhesive layer on both sides, and the attachment member is It arrange | positions so that it may overlap with the base end part of a notch, It is characterized by the above-mentioned.

  The present invention also provides an image forming apparatus including the developing device having the above-described configuration.

  According to the first configuration of the present invention, in the groove-like recess formed in the wall portion over substantially the entire longitudinal direction, the rotation shaft and a number of dispersion protrusions formed on the outer peripheral surface of the rotation shaft Is disposed so that the dispersion protrusions are in contact with the inner surface of the recess, so that the lump of toner floating and deposited on the wall is rubbed between the dispersion protrusion and the inner surface of the recess. In addition, the toner particles can be dispersed by the vibration of the dispersing projections and separated from the wall portion, and can be placed on the air flow generated by the rotation of the developer carrying member, thereby preventing toner from being deposited on the wall portion. Thereby, toner accumulation around the blade in the casing can be effectively suppressed regardless of the linear velocity of the developing device.

  According to the second configuration of the present invention, in the developing device of the first configuration, the wall portion is a downward slope from the facing region side toward the blade side, and the toner dispersion member is formed of a concave portion. By rotating in the downward slope direction along the inner surface, the toner accumulated in the recesses can be scraped out to the outside efficiently.

  Further, according to the third configuration of the present invention, in the developing device having the first or second configuration, the air inflow that allows external air to flow into the inside of the developing container between the concave portion of the wall portion and the blade. By forming an air outflow hole at the upper end of the developer container that allows the air inside the developer container to flow outside, even if the toner separated from the wall falls to the periphery of the blade, the air flows in. It can be sent to the air outflow hole on the airflow coming in from the hole. Therefore, toner accumulation can be more effectively suppressed.

  Further, according to the fourth configuration of the present invention, in the developing device having any one of the first to third configurations, the dispersion protrusion is formed by cutting the flexible film member. As with rollers and sponge rollers, hair loss and sponge tearing do not occur, and assembly is improved. Therefore, the toner dispersion member is simple, low cost and excellent in durability. In addition, since the foreign matter caused by the dispersion protrusion does not enter the developing container, it is possible to prevent the occurrence of image defects such as a blank image.

  According to the fifth configuration of the present invention, in the developing device of the fourth configuration, the ribbon-shaped film member in which a large number of cuts are formed along one side in the longitudinal direction is provided on the outer peripheral surface of the rotating shaft. The dispersion protrusions can be easily formed on the outer peripheral surface of the rotating shaft by forming the dispersion protrusions by spirally winding the protrusions along.

  According to the sixth aspect of the present invention, in the developing device of the fifth aspect, the film member is formed by inclining the cut formed in the film member by a predetermined angle from a direction perpendicular to the longitudinal direction. Since the portion that has been cut when it is wound around the outer peripheral surface of the rotating shaft rises at a constant angle with respect to the rotating shaft, the dispersion protrusions can be formed uniformly and easily.

  According to the seventh configuration of the present invention, in the developing device having the fifth or sixth configuration, the engagement protrusion is formed at both ends of the film member, and is engaged at two locations on the outer peripheral surface of the rotating shaft. By forming the engaging portion having a slit into which the protrusion is inserted, both end portions of the film member can be easily fixed, and peeling of both end portions can be prevented.

  Further, according to the eighth configuration of the present invention, in the developing device of the seventh configuration, the hook portion wider than the slit of the engagement portion is formed at the tip of the engagement protrusion. It is possible to reliably prevent the engagement protrusion from coming off from the slit.

  According to the ninth configuration of the present invention, in the developing device having any one of the fifth to eighth configurations, a spiral shape or a spiral pattern is formed on the outer peripheral surface of the rotation shaft in accordance with the winding position of the film member. By forming the film member along the spiral shape or spiral pattern, the film member can be efficiently wound at a predetermined pitch, and the assembly workability of the toner dispersion member is improved.

  According to the tenth configuration of the present invention, in the developing device having any one of the fifth to ninth configurations, the film member has a longitudinal edge of the fixed portion, and both ends of the film member. By forming the 1st inclination part which inclines toward, the edge of the winding start part and winding end part of a film member becomes substantially perpendicular | vertical with respect to a rotating shaft. Accordingly, the film member can be easily positioned with respect to the rotation shaft, and workability is improved.

  According to the eleventh configuration of the present invention, in the developing device having any one of the fifth to tenth configurations, the film member is wound around the rotating shaft around the edge of the portion where the cut is formed. When the second inclined portion is formed on the end side in the direction in which the tip of the dispersion projection faces, the tip of the dispersion projection can be aligned substantially perpendicular to the rotation axis at the winding reference side edge. Therefore, when the toner dispersion member is disposed in the recess of the scraper unit, the gap between the longitudinal ends of the portion where the dispersion protrusion is formed and the inner surface of the recess can be made as small as possible. And the occurrence of toner accumulation can be suppressed.

  According to the twelfth aspect of the present invention, in the developing device having the structure described in the fourth aspect, the fan-shaped film member in which a large number of cuts are formed from the outer peripheral edge toward the inner peripheral edge is used as the rotation shaft. By wrapping a plurality of conical shapes at a predetermined pitch to form the dispersion protrusion, the thickness and hardness of the film member forming the dispersion protrusion in one toner dispersion member can be changed. Therefore, the dispersibility in the longitudinal direction of the toner dispersion member can be arbitrarily adjusted. In addition, the maintainability of the toner dispersion member is improved.

  According to the thirteenth configuration of the present invention, in the toner dispersion mechanism having any one of the fourth to twelfth configurations, the dispersion protrusion is fixed while being inclined with respect to the axial direction of the rotation shaft. By making the projection length of the projections on the rotation axis larger than the pitch of the dispersion projections in the direction of the rotation axis, it is possible to prevent the toner from being poorly dispersed due to the blocky toner passing through the dispersion projections.

  According to the fourteenth configuration of the present invention, in the toner dispersion mechanism of any one of the fourth to thirteenth configurations, a film member is formed using a tape-like adhesive member having an adhesive layer or an adhesive layer on both sides. Is fixed to the rotating shaft, and the sticking member is disposed so as to overlap the base end portion of the cut, so that the base end portion of the cut is reinforced by the sticking member, thereby preventing the dispersal protrusion from being broken. be able to.

  According to the fifteenth configuration of the present invention, the image forming apparatus including the developing device having any one of the first to fourteenth configurations makes it possible to leak toner from the facing region due to toner accumulation. And image defects such as toner dropping can be prevented.

1 is a schematic configuration diagram of an image forming apparatus including a developing device according to an embodiment of the present disclosure. 1 is a schematic side sectional view of a developing device according to a first embodiment of the present invention. A perspective view of the scraper unit as seen from the inner wall surface side Side sectional view of the scraper unit A perspective view of a toner dispersion member disposed in a recess of the scraper unit Partial enlarged view of the vicinity of both ends of the toner dispersion member Development view of dispersion protrusion used for toner dispersion member Schematic side view showing operation of toner dispersion member Partial enlarged view of the film member showing a state in which the double-sided tape 56 is attached so as to overlap the base end portion 53 a of the cut 53. Development view showing another example of the dispersion protrusion used in the toner dispersion member FIG. 10 is a perspective view of a toner dispersion member formed by winding the dispersion protrusion of FIG. 10 around a rotation shaft. FIG. 5 is a partial cross-sectional view of the toner dispersing member shown in FIG. 5 in the rotation axis direction. The perspective view of the rotating shaft used for the toner dispersion member shown in FIG. FIG. 5 is a longitudinal sectional view of a rotating shaft used in the toner dispersing member shown in FIG. The side view which shows the modification of the rotating shaft used for the toner dispersion member shown in FIG. The side view which shows the other modification of the rotating shaft used for the toner dispersion member shown in FIG. FIG. 5 is a development view illustrating another example of the dispersion protrusion used in the toner dispersion member illustrated in FIG. 5. FIG. 17 is a perspective view of a toner dispersion member formed by winding the dispersion protrusion of FIG. 17 around a rotation shaft. Schematic side sectional view of a developing device according to a second embodiment of the present invention Schematic side sectional view showing a developing device provided with an air inflow hole in the wall of the developing container

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an image forming apparatus equipped with the developing device of the present invention. Here, a tandem color image forming apparatus is shown. In the main body of the color printer 100, four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (the right side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively performed by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  These image forming portions Pa to Pd are provided with photosensitive drums 1a, 1b, 1c and 1d which carry visible images (toner images) of the respective colors, and are further illustrated by a driving means (not shown). In FIG. 1, an intermediate transfer belt 8 that rotates clockwise is provided adjacent to each of the image forming portions Pa to Pd. The toner images formed on the photosensitive drums 1a to 1d are sequentially primary-transferred and superimposed on the intermediate transfer belt 8 that moves while contacting the photosensitive drums 1a to 1d, and then the secondary transfer roller. 9 is secondarily transferred onto a transfer paper P as an example of a recording medium, and further fixed on the transfer paper P in the fixing unit 13 and then discharged from the apparatus main body. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d counterclockwise in FIG.

  The transfer paper P onto which the toner image is transferred is accommodated in a paper cassette 16 disposed at the lower part of the main body of the color printer 100, and is connected to the secondary transfer roller 9 and a later-described roller via a paper feed roller 12a and a registration roller pair 12b. The intermediate transfer belt 8 is conveyed to a nip portion with the driving roller 11. A sheet made of dielectric resin is used for the intermediate transfer belt 8, and a (seamless) belt having no seam is mainly used. A blade-like belt cleaner 19 for removing toner remaining on the surface of the intermediate transfer belt 8 is disposed downstream of the secondary transfer roller 9.

  Next, the image forming units Pa to Pd will be described. There are chargers 2a, 2b, 2c, and 2d for charging the photosensitive drums 1a to 1d and image information on the photosensitive drums 1a to 1d around and below the photosensitive drums 1a to 1d that are rotatably arranged. The exposure device 5 for exposing the toner, the developing devices 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and the developer (toner) remaining on the photosensitive drums 1a to 1d are removed. Cleaning parts 7a, 7b, 7c and 7d are provided.

  When image data is input from a host device such as a personal computer, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d, and then light is irradiated according to the image data by the exposure device 5. The electrostatic latent images corresponding to the image data are formed on the respective photosensitive drums 1a to 1d. Each of the developing devices 3a to 3d is filled with a predetermined amount of a two-component developer containing toner of each color of cyan, magenta, yellow, and black. If the ratio of the toner in the two-component developer filled in the developing devices 3a to 3d is less than a specified value due to the formation of a toner image, which will be described later, each developing from the toner containers (replenishing means) 4a to 4d. The toner is supplied to the devices 3a to 3d. The toner in the developer is supplied onto the photosensitive drums 1a to 1d by the developing devices 3a to 3d and electrostatically adheres to the electrostatic latent image formed by the exposure from the exposure device 5. A toner image is formed.

  The primary transfer rollers 6a to 6d apply an electric field at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d, and cyan, magenta, yellow, and yellow on the photosensitive drums 1a to 1d. A black toner image is primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, in preparation for the subsequent formation of a new electrostatic latent image, the toner remaining on the surfaces of the photosensitive drums 1a to 1d after the primary transfer is removed by the cleaning units 7a to 7d.

  The intermediate transfer belt 8 is stretched over an upstream driven roller 10 and a downstream drive roller 11, and the intermediate transfer belt 8 rotates clockwise as the drive roller 11 is rotated by a drive motor (not shown). When the rotation starts, the transfer paper P is conveyed from the registration roller 12b to the nip portion (secondary transfer nip portion) between the drive roller 11 and the secondary transfer roller 9 provided adjacent thereto at a predetermined timing. The full color image on the intermediate transfer belt 8 is transferred onto the transfer paper P. The transfer paper P onto which the toner image is transferred is conveyed to the fixing unit 13.

  The transfer paper P conveyed to the fixing unit 13 is heated and pressurized by the fixing roller pair 13a, and the toner image is fixed on the surface of the transfer paper P, so that a predetermined full color image is formed. The transfer paper P on which the full-color image is formed is distributed in the transport direction by the branching portion 14 that branches in a plurality of directions. When an image is formed only on one side of the transfer paper P, it is discharged as it is onto the discharge tray 17 by the discharge roller 15.

  On the other hand, when forming images on both sides of the transfer paper P, the transfer paper P that has passed through the fixing unit 13 is once transported in the direction of the discharge roller 15, and the discharge roller after the rear end of the transfer paper P has passed through the branching unit 14. 15 is rotated in the reverse direction and the conveyance direction of the branching portion 14 is switched, so that the paper is distributed from the rear end of the transfer paper P to the paper conveyance path 18 and re-conveyed to the secondary transfer nip portion with the image surface reversed. . Then, after the next image formed on the intermediate transfer belt 8 is transferred by the secondary transfer roller 9 to the surface of the transfer paper P where the image is not formed and conveyed to the fixing unit 13 and the toner image is fixed. , And discharged to the discharge tray 17.

  Further, an exhaust fan 90 is provided on the back side of the apparatus main body, and the exhaust fan 90 discharges air inside the apparatus main body to the outside of the apparatus main body.

  FIG. 2 is a schematic side sectional view of the developing device according to the first embodiment of the present invention. 2 shows a state viewed from the back side of FIG. 1, and the arrangement of each member in the developing device is opposite to that in FIG. Further, the developing device 3a disposed in the image forming unit Pa in FIG. 1 will be described here, but the configuration of the developing devices 3b to 3d disposed in the image forming units Pb to Pd is basically the same, and thus described. Is omitted.

  As shown in FIG. 2, the developing device 3a includes a developing container (casing) 20 in which a two-component developer (hereinafter simply referred to as a developer) is accommodated. The developing container 20 is separated by partition walls 20a and 20b. The agitating and conveying chamber 21, the supply and conveying chamber 22, and the recovery and conveying chamber 23 are partitioned. In the agitating / conveying chamber 21 and the supply / conveying chamber 22, the agitating / conveying screw 25 a for supplying toner (positively charged toner) supplied from the toner container 4 a (see FIG. 1) with the carrier, agitating and charging, and the supplying and conveying Each screw 25b is rotatably arranged. In addition, a collection conveyance chamber 23 provided above the vicinity of the boundary between the supply conveyance chamber 22 and the stirring conveyance chamber 21 has a collection conveyance screw 25c for conveying the developer peeled off from a magnetic roller 30 (described later). It is rotatably arranged.

  Then, the developer is agitated by the agitating and conveying screw 25a and the supply and conveying screw 25b while being conveyed in the axial direction (perpendicular to the paper surface of FIG. 2), and passes through the developer (not shown) formed at both ends of the partition wall 20a. It circulates between the stirring and conveying chamber 21 and the supply and conveying chamber 22 through the path. Further, the developer peeled off from the magnetic roller 30 (described later) is transported in the axial direction by the recovery transport screw 25c, and the developer in the supply stirring chamber 22 from a communication portion (not shown) formed at one end of the partition wall 20b. To join. That is, a developer circulation path is formed in the developer container 20 by the agitation transport chamber 21, the supply transport chamber 22, the recovery transport chamber 23, the developer passage, and the communication portion.

  The developing container 20 extends obliquely to the upper right in FIG. 2, and a magnetic roller 30 (developer carrying member) is disposed above the supply / conveying screw 25 b in the developing container 20. A developing roller 31 is disposed opposite to the developing roller 31. The developing roller 31 faces the photosensitive drum 1a (see FIG. 1) on the opening side (the right side in FIG. 2) of the developing container 20, and the magnetic roller 30 rotates counterclockwise in the figure with respect to the respective rotation axes. The developing roller 31 rotates counterclockwise in the figure.

  In the agitating / conveying chamber 21, a toner concentration sensor (not shown) is disposed so as to face the agitating / conveying screw 25a, and agitation is performed from the toner container 4a via a toner supply port (not shown) based on the detection result of the toner concentration sensor. The transfer chamber 21 is supplied with toner. As the toner concentration sensor, for example, a magnetic permeability sensor that detects the magnetic permeability of a two-component developer composed of toner and magnetic carrier in the developing container 20 is used.

  The magnetic roller 30 is composed of a non-magnetic rotating sleeve that rotates counterclockwise in FIG. 2 and a fixed magnet body that has a plurality of magnetic poles contained in the rotating sleeve.

  The developing roller 31 includes a cylindrical developing sleeve that rotates counterclockwise in FIG. 2 and a developing roller-side magnetic pole fixed in the developing sleeve. The magnetic roller 30 and the developing roller 31 face each other. It faces with a predetermined gap at (opposite position). The developing roller side magnetic pole has a different polarity from the opposing magnetic pole (main pole) of the fixed magnet body.

  Further, a spike cutting blade 33 is attached to the developing container 20 along the longitudinal direction of the magnetic roller 30 (perpendicular to the paper surface of FIG. 2), and the spike cutting blade 33 rotates in the direction of rotation of the magnetic roller 30 (see FIG. In the counterclockwise direction), it is positioned upstream of the position where the developing roller 31 and the magnetic roller 30 face each other. A slight gap (gap) is formed between the tip of the ear cutting blade 33 and the surface of the magnetic roller 30.

  A DC voltage (hereinafter referred to as Vslv (DC)) and an AC voltage (hereinafter referred to as Vslv (AC)) are applied to the developing roller 31, and a DC voltage (hereinafter referred to as Vmag (DC)) is applied to the magnetic roller 30. And an alternating voltage (hereinafter referred to as Vmag (AC)) is applied. These DC voltage and AC voltage are applied to the developing roller 31 and the magnetic roller 30 from a developing bias power source via a bias control circuit (both not shown).

  As described above, the developer is agitated by the agitating / conveying screw 25a and the supply / conveying screw 25b, and the toner is charged by circulating through the agitating / conveying chamber 21 and the supplying / conveying chamber 22 in the developing container 20, and the supply / conveying screw 25b. The developer is conveyed to the magnetic roller 30. Then, a magnetic brush (not shown) is formed on the magnetic roller 30, and the layer thickness of the magnetic brush on the magnetic roller 30 is regulated by the earbrushing blade 33, and then the opposite portion between the magnetic roller 30 and the developing roller 31. A thin toner layer is formed on the developing roller 31 by the potential difference ΔV between the Vmag (DC) conveyed and applied to the magnetic roller 30 and the Vslv (DC) applied to the developing roller 31 and a magnetic field.

  The toner layer thickness on the developing roller 31 varies depending on the resistance of the developer and the difference in rotational speed between the magnetic roller 30 and the developing roller 31, but can be controlled by ΔV. When ΔV is increased, the toner layer on the developing roller 31 is thickened, and when ΔV is decreased, the toner layer is thinned. The range of ΔV at the time of development is generally about 100V to 350V.

  The toner thin layer formed on the developing roller 31 by contact with the magnetic brush on the magnetic roller 30 is conveyed to a facing portion (facing region) between the photosensitive drum 1 a and the developing roller 31 by the rotation of the developing roller 31. . Since Vslv (DC) and Vslv (AC) are applied to the developing roller 31, the toner flies due to a potential difference with the photosensitive drum 1a, and the electrostatic latent image on the photosensitive drum 1a is developed. .

  The remaining toner that is not used for development is conveyed again to the opposite portion between the developing roller 31 and the magnetic roller 30 and is collected by the magnetic brush on the magnetic roller 30. Then, the magnetic brush is peeled off from the magnetic roller 30 at the same pole portion of the fixed magnet body, and then falls into the collection conveyance chamber 23. The developer in the collection conveyance chamber 23 is conveyed in the axial direction by the collection conveyance screw 25c, and merges with the developer in the supply conveyance chamber 22 from a communication portion (not shown).

  Thereafter, a predetermined amount of toner is replenished from a toner replenishing port (not shown) based on a detection result of a toner concentration sensor (not shown), and an appropriate toner concentration is again obtained while circulating through the supply transport chamber 22 and the stirring transport chamber 21. The two-component developer is uniformly charged. This developer is again supplied onto the magnetic roller 30 by the supply stirring screw 25 b to form a magnetic brush, and is conveyed to the ear cutting blade 33.

  In the vicinity of the developing roller 31 on the right side wall of the developing container 20 in FIG. 2, a scraper unit 35 having a triangular cross section that protrudes inside the developing container 20 and holds the ear cutting blade 33 is provided. As shown in FIG. 2, the scraper unit 35 is disposed along the longitudinal direction of the developing container 20 (perpendicular to the paper surface of FIG. 2), and the scraper unit 35 faces the magnetic roller 30 and the developing roller 31. The wall surface 35 a is inclined downward from the developing roller 31 toward the magnetic roller 30. The scraper unit 35 is formed with a recess 35b that is recessed from the inner wall surface 35a along the longitudinal direction, and the toner dispersion member 40 is rotatably supported in the recess 35b.

  3 is a perspective view of the scraper unit 35 as seen from the inner wall surface 35a side, FIG. 4 is a side sectional view of the scraper unit 35, and FIG. 5 is a perspective view of a toner dispersion member disposed in the recess 35b of the scraper unit 35. It is. Portions common to FIG. 2 are denoted by the same reference numerals and description thereof is omitted.

  The toner dispersion member 40 has a large number of dispersion protrusions 40b formed of an elastic material on the outer peripheral surface of the rotating shaft 40a. In the concave portion 35b of the scraper unit 35, bearing holes 35c for rotatably supporting the rotary shaft 40a are formed at both ends in the longitudinal direction. One end of the rotating shaft 40a (here, the front side in the drawing) passes through the bearing hole 35c and extends to the outside of the scraper unit 35, and the drive input gear 50 is fixed. The drive input gear 50 is connected to drive input gears (not shown) of the magnetic roller 30 and the developing roller 31 via a gear train (not shown). Further, the tip of the dispersion protrusion 40 b is disposed so as to contact the inner surface of the recess 35 b of the scraper unit 35.

  6 is a partially enlarged view of the vicinity of both ends of the toner dispersion member in FIG. 5, and FIG. 7 is a development view of the dispersion protrusions used in the toner dispersion member. In the toner dispersion member 40 according to the present embodiment, a large number of cuts 53 are formed on one side (upper side in FIG. 7) of the ribbon-shaped film member 51, and a portion where the cuts 53 are not formed is used as a fixing portion 54. The film member 51 is spirally wound around the outer peripheral surface of the rotating shaft 40a with the notch 53 facing outward to form the dispersion protrusion 40b.

  As shown in FIG. 7, the cut 53 is formed not diagonally to the longitudinal direction of the film member 51 but obliquely. Thereby, when the film member 51 is wound around the outer peripheral surface of the rotary shaft 40a, the portion where the cut 53 is inserted rises at a certain angle with respect to the rotary shaft 40a, so that the dispersion protrusions 40b are not spread by hand. It can be formed uniformly and easily. The rising angle of the dispersion protrusion 40 b with respect to the rotation shaft 40 a can be arbitrarily adjusted by the angle of the cut 53.

  Engaging protrusions 55 are formed at both ends of the film member 51. As shown in FIG. 6, engaging portions 57 with which the engaging protrusions 55 are engaged at two locations on the outer peripheral surface of the rotating shaft 40a. Is protruding. A double-sided tape 56 is attached to the fixed portion 54 of the film member 51 over the entire longitudinal direction. When assembling the toner dispersion member 40, the engagement protrusion 55 at one end of the film member 51 is inserted into the slit 57a of one engagement portion 57, and the film member 51 is attached with the double-sided tape 56 while being wound around the rotation shaft 40a. By inserting the engaging protrusion 55 at the other end into the slit 57a of the other engaging portion 57, the film member 51 can be easily fixed to the rotating shaft 40a.

  FIG. 8 is a schematic side view showing the operation of the toner dispersion member 40. As shown in FIG. 8, when the toner dispersion member 40 disposed in the recess 35b rotates in the clockwise direction in the figure, the dispersion protrusion 40b rubs the inner surface of the recess 35b. As a result, the toner accumulated in the recess 35b is dispersed finely and then efficiently scraped to the outside. Further, the dispersion protrusion 40b elastically deformed in contact with the inner surface of the recess 35b tries to return to its original shape with a restoring force when being separated from the recess 35b, and vibrates in a direction perpendicular to the inner wall surface 35a. .

  Due to the vibration of the dispersion protrusions 40b, the toner scraped out from the recesses 35b is lifted up and separated from the inner wall surface 35a, and the air flow generated by the rotation of the developing roller 31 and the magnetic roller 30 (solid arrow in FIG. 8). And can be sent to a space above the magnetic roller 30.

  Thereby, even when the magnetic roller 30 and the developing roller 31 in the developing device 3a rotate at a high speed and the toner floating amount is large, toner accumulation on the inner wall surface 35a can be prevented. Accordingly, contamination in the main body of the image forming apparatus 100 due to the toner being discharged from the opening facing the photoconductive drum 1a, an image defect in which the accumulated toner aggregates and adheres to the developing roller 31, and the toner drops. Can be effectively suppressed without depending on the linear velocity of the developing device 3a.

  Further, since the dispersion protrusions 40b are formed of the film member 51, the hair dispersion and the sponge are not broken like the flocking brush roller and the sponge roller, so that the toner dispersion member 40 having excellent durability can be obtained. Further, since there is no possibility that foreign matter caused by the toner dispersion member 40 enters the developing container 20, image defects such as white spots caused by foreign matter being caught in the gap between the spike cutting blade 33 and the magnetic roller 30 are effectively prevented. Can be prevented. As a material of the film member 51, a PET film or a urethane sheet excellent in flexibility and resilience (elasticity) is preferable.

  Further, when the film member 51 is wound around the rotation shaft 40a to form the toner dispersion member 40, a load is applied to the dispersion protrusion 40b, and the notch 53 may be further broken to break the dispersion protrusion 40b. Therefore, when the double-sided tape 56 is affixed to the fixing portion 54, it is preferable that the double-sided tape 56 is affixed so as to overlap the base end portion 53a of the cut 53 as shown in FIG. By sticking in this way, the base end portion 53a of the cut 53 is reinforced by the double-sided tape 56, so that the dispersal projection 40b can be prevented from being broken.

  FIG. 10 is a development view showing another example of the dispersion protrusion used for the toner dispersion member, and FIG. 11 is a perspective view of the toner dispersion member formed by winding the dispersion protrusion of FIG. 10 around the rotation shaft. In this configuration, a large number of cuts 53 are formed inward from the outer peripheral edge of the fan-shaped film member 51 as shown in FIG. 10, and the inner peripheral edge where the cuts 53 of the film member 51 are not formed is fixed. 54, a double-sided tape 56 is attached to the fixing portion 54. A plurality of the film members 51 are wound conically around the rotation shaft 40a at a predetermined pitch to form the dispersion protrusions 40b.

  In the toner dispersing member 40 shown in FIG. 11 as well, there is no possibility that foreign matters caused by the toner dispersing member 40 enter the developing container 30 as in the first embodiment, and it is possible to effectively prevent defects such as white images. be able to.

  Further, in the toner dispersion member 40 of FIG. 11, since the dispersion protrusions 40 b are formed by a plurality of film members 51, the thickness and hardness of the film member 51 that forms the dispersion protrusions 40 b in one toner dispersion member 40. (Koshi) can be changed. Therefore, the dispersibility in the longitudinal direction of the toner dispersion member 40 can be arbitrarily adjusted. Further, when the dispersion protrusion 40b is partially deteriorated due to a change with time or the like, only the film member 51 in the deteriorated portion needs to be replaced, so that the maintainability of the toner dispersion member 40 is improved.

  Moreover, it is preferable to affix the double-sided tape 56 so that it may overlap with the base end part 53a of the notch 53 similarly to the dispersion | distribution protrusion shown in FIG.

  FIG. 12 is a partial cross-sectional view of the toner dispersion member 40 shown in FIG. 5 in the direction of the rotation axis 40a. As shown in FIG. 12A, the relationship between the distance (pitch) a of the dispersion protrusions 40b in the thrust direction of the rotation shaft 40a and the projection length b of the dispersion protrusions 40b viewed from the direction perpendicular to the rotation shaft 40a. Is a ≧ b, the lump of toner that has fallen into the concave portion 35b of the scraper unit 35 passes through the gap of the dispersion projection 40b, and is scraped out of the concave portion 35b without being sufficiently dispersed and onto the magnetic roller 30. There is a risk of falling.

  On the other hand, as shown in FIG. 12B, when a <b, the lump-like toner that has fallen into the concave portion 35b of the scraper unit 35 always comes into contact with the dispersion projection 40b and is conveyed in the longitudinal direction. Finely dispersed. Therefore, it is preferable that the dispersion protrusions 40b be fixed to be inclined by a predetermined amount with respect to the rotation shaft 40a so that a <b. Also in the toner dispersing member 40 shown in FIG. 11, the pitch a and the projection length b of the dispersion projection 40b are fixed so as to satisfy a <b as shown in FIG. Similar to the configuration shown, the block of toner can be efficiently dispersed by swinging the dispersion protrusions 40b.

  Further, the density of the dispersion protrusions 40b increases as the pitch a of the dispersion protrusions 40b decreases, and the dispersible area of the dispersion protrusions 40b increases as the projection length b (brush length) of the dispersion protrusions 40b increases. Also, the toner dispersion effect is enhanced. Accordingly, by partially varying the pitch a and the projection length b of the dispersion projections 40b according to the arrangement of the scraper unit 35 and the shape of the recesses 35b, the dispersion effect by the toner dispersion member 40 can be set appropriately. .

  The pitch a of the dispersion protrusions 40b can be adjusted by changing the width w1 (see FIGS. 7 and 10) of the fixing portion 54 of the film member 51. Further, in the case of the toner dispersing member 40 shown in FIG. 5, the adjustment can also be made by changing the winding angle of the film member 51 with respect to the rotating shaft 40a. Further, the projection length b of the dispersion projection 40b can be adjusted by changing the length w2 (see FIGS. 7 and 10) of the cut 53 of the film member 51.

  13 and 14 are a perspective view and a cross-sectional view of a rotating shaft used in the toner dispersing member shown in FIG. Since the structure of the film member 51 is the same as that of FIG. 7, description is abbreviate | omitted. As shown in FIGS. 13 and 14, a spiral stepped portion 60 is formed at a portion around which the film member 51 of the rotating shaft 40 a is wound. Further, the pitch p of the stepped portion 60 is substantially equal to the width w1 of the fixed portion 54 of the film member 51.

  By winding the film member 51 along the step portion 60 of the rotating shaft 40a shown in FIGS. 13 and 14, the film member 51 can be efficiently wound at a predetermined pitch, and the assembly workability of the toner dispersing member 40 can be improved. improves. Moreover, as shown in FIG. 13, since the step part 60 is inclined in the outer diameter direction of the rotating shaft 40a, the notch 53 is easily spread when the film member 51 is wound. Thereby, the dispersion protrusion 40b can be raised at a wide angle with respect to the rotation shaft 40a.

  15 and 16 are side views showing modifications of the rotating shaft used in the toner dispersing member shown in FIG. A rotating shaft 40 a shown in FIG. 15A is formed with a spiral protrusion 61 instead of the stepped portion 60, and the film member 51 is wound around a portion partitioned by the protrusion 61 to form the toner dispersion member 40. To do. A rotating shaft 40 a shown in FIG. 15B has a helical recess 62 instead of the stepped portion 60, and the film member 51 is wound around the recess 62 to form the toner dispersion member 40. In these cases, there is no effect of raising the dispersion protrusions 40b at a wide angle unlike the stepped portion 60, but the film member 51 can be efficiently wound at a predetermined pitch as in the case where the stepped portion 60 is provided. Assembling workability of the toner dispersion member 40 is improved.

  Further, the rotating shaft 40a shown in FIG. 16 is drawn with a spiral mark line 63 by printing or the like instead of the stepped portion 60. Even in this case, although the effect is slightly inferior to that of the stepped portion 60 and the protrusion 61, the workability of assembling the toner dispersing member 40 is improved by winding the film member 51 along the mark line 63.

  FIG. 17 is a developed view showing another example of the dispersion protrusion used in the toner dispersion member shown in FIG. 5, and FIG. 18 shows the toner dispersion by spirally winding the dispersion protrusion of FIG. It is the perspective view used as the member. In this configuration, a first inclined portion 65 that is inclined toward both end portions is formed in the fixing portion 54 of the film member 51.

  Further, when the film member 51 is wound around the rotation shaft 40a, the first inclined portion is formed by cutting the front end portion of the cut 53 obliquely at the axial end portion (winding reference side) where the front end of the dispersion projection 40b faces. A second inclined portion 67 that is inclined in the same direction as 65 is formed. Furthermore, a hook part 70 wider than the slit 57a of the engaging part 57 of the rotating shaft 40a is formed at the tip of the engaging protrusion 55 provided at both ends of the film member 51.

  According to this configuration, by forming the hook portion 70 at the tip of the engagement projection 55, the engagement projection 55 can be reliably prevented from coming off from the engagement portion 57. Further, by forming the first inclined portion 65 in the fixing portion 54 of the film member 51, the edges of the winding start portion and the winding end portion of the film member 51 become straight lines L1 and L2 substantially perpendicular to the rotation shaft 40a. Overlap. Therefore, the film member 51 can be easily positioned with respect to the rotation shaft 40a simply by aligning the first inclined portion 65 substantially perpendicular to the rotation shaft 40a, and the workability is improved. Moreover, since the hook part 70 can be inserted substantially perpendicularly with respect to the engaging part 57, the insertion work is also facilitated.

  Furthermore, by forming the second inclined portion 67 on the cut 53 side, the tip of the dispersion projection 40b can be aligned along the straight line L2 at the edge on the winding reference side. As a result, when the toner dispersion member 40 is disposed in the recess 35b of the scraper unit 35, the gap between the tip of the dispersion projection 40b and the inner surface of the longitudinal end of the recess 35b can be made as small as possible. The effect can be enhanced. Further, since the toner lump adhering to the inner surface of the recess 35b is scraped off by the dispersion protrusion 40b, the occurrence of toner accumulation can be suppressed.

  FIG. 19 is a schematic side sectional view of a developing device according to the second embodiment of the present invention. Portions common to those in FIG. 2 are denoted by common reference numerals and description thereof is omitted. As shown in FIG. 19, in this embodiment, the scraper unit 35 is formed with an air inflow hole 35 d that connects the inside and the outside of the developing container 20, and the air that communicates with the duct 80 is formed at the upper end of the developing container 20. An outflow hole 20d was formed. Other configurations are the same as those of the first embodiment shown in FIG.

  As shown in FIG. 19, the air inflow hole 35d is formed in a plurality of slits along the longitudinal direction (the direction perpendicular to the paper surface). As a result, air flows from the outside to the inside of the developing container 20 through the air inflow hole 35d, and the air flow from the outside is generated by the developing roller 31 and the magnetic roller 30 as described above (see FIG. 19). It enters into the vicinity of the ear cutting blade 33 which becomes negative pressure by the solid line arrow) and merges with this air flow. As a result, even if the toner separated from the wall portion 20c by the toner dispersing member 40 falls to the vicinity of the ear-cutting blade 33, it can be sent upward in the air flow.

  Further, a duct 80 is disposed above the developing container 20, and an air outflow hole 20 d communicating with the duct 80 is formed at the upper end of the developing container 20. The duct 80 is connected to the exhaust fan 90 (see FIG. 1). In addition, a filter (not shown) is disposed at a connection portion between the exhaust fan 90 and the duct 80 so that toner or the like is captured by the filter.

  As a result, air is discharged toward the air outflow hole 20d from a space surrounded by the developing roller 31, the magnetic roller 30, and the ear cutting blade 33 and having a positive pressure. Accordingly, since an air flow path from the air inflow hole 35d to the air outflow hole 20d is formed, toner separated from the inner wall surface 35a and the recess 35b by the toner dispersing member 40 is discharged from the air outflow hole 20d, and the filter Can be recovered.

  In the present embodiment, since the air inflow hole 35d that connects the inside and the outside of the developing container 20 is formed in the scraper unit 35, toner accumulation can be more effectively prevented. Further, since the air outflow hole 20d communicating with the duct 80 is formed at the upper end portion of the developing container 20, toner accumulation can be prevented more effectively and toner leakage from the developing container 20 can be prevented.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, the toner dispersion member 40 shown in the above embodiment is an example and is not particularly limited to the above embodiment, and these can be appropriately set according to the apparatus configuration and the like.

  In the above-described embodiment, the present invention uses a two-component developer, forms a magnetic brush on the magnetic roller 30, moves only the toner from the magnetic roller 30 to the developing roller 31, and then develops the photosensitive drum from the developing roller 31. The present invention is applied to the developing devices 3a to 3d that supply toner to 1a to 1d. However, the present invention is also applied to a developing device that uses a one-component developer, or a developing device that has only the developing roller 31 without the magnetic roller 30. Can do. In the above embodiment, the tandem color printer 100 has been described as an example. However, the present invention can be applied to, for example, monochrome and color copiers, digital multifunction peripherals, monochrome printers, facsimiles, and the like. Not too long.

  In the present invention, the casing has a wall portion facing the developer carrying member between the blade and the opposed region, and a groove-like concave portion formed on the wall portion over substantially the entire length direction, And a toner dispersing member disposed so as to be in contact with the inner wall surface of the recess. Thereby, toner accumulation in the casing of the developing device can be effectively prevented. Further, by using the image forming apparatus including the developing device, it is possible to effectively prevent image defects such as toner dropping due to toner accumulation.

Pa to Pd Image forming section 1a to 1d Photosensitive drum (image carrier)
3a to 3d Developing device 4a to 4d Toner container 20 Developing container (casing)
20a, 20b Partition wall 20c Wall portion 20ca Inner wall surface 20cb Recessed portion 20cc Through hole 20d Air outflow hole 30 Magnetic roller (developer carrier)
31 Developing roller (developer carrier)
33 Hobiri Blade (Blade)
35 Scraper unit 35a Inner wall surface (wall)
35b Concave portion 35d Air inflow hole 40 Toner dispersion member 40a Rotating shaft 40b Dispersion projection 51 Film member 53 Cut 53a Base end portion 54 Fixing portion 55 Engagement projection 56 Double-sided tape (attachment member)
57 engaging portion 57a slit 61 ridge 62 concave portion 63 mark line 65 first inclined portion 67 second inclined portion 70 hook portion 80 duct 90 exhaust fan 100 color printer (image forming apparatus)

Claims (15)

A developer carrier that is arranged opposite to an image carrier on which an electrostatic latent image is formed and supplies developer to the image carrier in a region facing the image carrier;
A blade for regulating the amount of developer carried on the developer carrying member;
A casing for housing the blade and the developer carrier;
A developing device comprising:
The casing has a wall portion facing the developer carrier between the blade and the facing region,
The wall is formed with a groove-like recess over substantially the entire length in the longitudinal direction, and the recess comprises a rotating shaft and a number of dispersion protrusions formed on the outer peripheral surface of the rotating shaft. A developing device, wherein the toner dispersion member is disposed so that the dispersion protrusions are in contact with the inner surface of the recess.   2. The wall portion has a downward slope from the facing region side toward the blade side, and the toner dispersion member rotates in a downward slope direction along an inner surface of the recess. The developing device according to 1.   An air inflow hole for allowing outside air to flow into the inside of the developing container is formed between the concave portion of the wall and the blade, and the air inside the developing container flows out to the outside at the upper end of the developing container. The developing device according to claim 1, wherein an air outflow hole is formed.   2. The dispersion projection is formed by winding a flexible film member having a large number of cuts on one side and winding the flexible film member around the outer peripheral surface of the rotating shaft with the cuts facing outward. The developing device according to claim 3.   The film member has a ribbon shape in which a large number of cuts are formed along one side in a longitudinal direction, and the dispersion protrusion has an outer periphery of the rotating shaft with a side on which the cuts of the film member are not formed as a fixed portion. The developing device according to claim 4, wherein the developing device is formed by being spirally wound along a surface.   6. The developing device according to claim 5, wherein the cut formed in the film member is inclined by a predetermined angle from a direction perpendicular to the longitudinal direction.   The engagement protrusions are formed at both ends of the film member, and the engagement portions having slits into which the engagement protrusions are inserted are formed at two locations on the outer peripheral surface of the rotating shaft. The developing device according to claim 5 or 6.   The toner dispersing member according to claim 7, wherein a hook portion wider than a slit of the engaging portion is formed at a tip of the engaging protrusion.   9. The developing device according to claim 5, wherein a spiral shape or a spiral pattern is formed on an outer peripheral surface of the rotation shaft in accordance with a winding position of the film member.   10. The first inclined portion that is inclined toward both ends of the film member is formed at an end edge of the fixing portion in the longitudinal direction of the film member. The developing device according to any one of the above.   The edge of the portion of the film member where the cut is formed is inclined toward the end of the film member toward the end in the direction in which the tip of the dispersion projection faces when wound around the rotating shaft. The developing device according to claim 5, wherein a second inclined portion is formed.   The film member has a fan shape in which a large number of cuts are formed from the outer peripheral edge toward the inner peripheral edge, and the dispersion protrusion is rotated with the inner peripheral side where the cuts of the film member are not formed as a fixed portion. 5. The developing device according to claim 4, wherein a plurality of conical pieces are wound around the shaft at a predetermined pitch.   The dispersion protrusion is fixed to be inclined with respect to the axial direction of the rotation shaft, and the projection length of the dispersion protrusion onto the rotation shaft is larger than the pitch of the dispersion protrusion in the rotation axis direction. 13. The developing device according to claim 4, wherein the developing device is characterized in that:   The film member is fixed to the rotating shaft using a tape-like attachment member having an adhesive layer or an adhesive layer on both sides, and the attachment member is disposed so as to overlap the base end portion of the cut. The developing device according to any one of claims 4 to 13, wherein the developing device.   An image forming apparatus comprising the developing device according to claim 1.

Images