JP2017156499A - Developing device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that can prevent fogging on an image due to uncharged or reversely-charged toner accumulated on a toner receiving member and scattering of the toner with a simple configuration, and an image forming apparatus including the same.SOLUTION: A developing device comprises: a developing roller; a toner supply roller; a regulating blade; a casing; a toner receiving support member; a toner receiving member; and vibration generating means. The toner receiving support member is arranged inside the casing and opposite to the developing roller or the toner supply roller. The toner receiving member is arranged along the longitudinal direction of the toner receiving support member and includes a toner receiving surface that receives toner dropping from the developing roller. The toner receiving support member has an opening formed in its top face extending along substantially the entire area in the longitudinal direction of the toner receiving support member to be overlapped with a lower end edge of the toner receiving surface. In the toner receiving support member, a toner retention part is provided which retains toner dropped from the opening due to vibration of the toner receiving member.SELECTED DRAWING: Figure 8

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 a 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 with the progress of color printing and high-speed processing, and the toner stirring member in the developing device is forced to rotate at high speed to cope with high-speed processing. . In particular, in a development method using a two-component developer including a magnetic carrier and a toner and using a magnetic roller (toner supply roller) that carries the developer and a development roller that carries only the toner, the development roller and the magnetic roller In the opposite portion, only the toner is carried on the developing roller by the magnetic brush formed on the magnetic roller, and the toner that has not been used for development is peeled off from the developing roller. For this reason, the toner easily floats in the vicinity of the portion where the developing roller and the magnetic roller face each other, and the floating toner accumulates around the ear cutting blade (regulating blade), and the deposited toner aggregates and adheres to the developing roller. Then, there is a risk that the toner will fall out and an image defect will occur.

  Therefore, for example, Patent Document 1 discloses a developing device that uses a two-component developer including a magnetic carrier and a toner and uses a magnetic roller that supports the developer and a developing roller that supports only the toner. Development provided with a toner receiving support member facing the roller, a toner receiving member that is disposed along the longitudinal direction of the toner receiving support member and that receives toner falling from the developing roller, and a vibration generating means that vibrates the toner receiving member An apparatus is disclosed.

  Patent Document 2 discloses a developing device in which a sheet-like vibration adjusting member is disposed at a predetermined distance from both ends of the toner receiving support member in the longitudinal direction. In this developing device, when the toner receiving member vibrates, the toner receiving member comes into contact with the vibration adjusting member, so that the free end of the toner receiving member vibrates so as to draw an arc and vibrates so as to be deposited on the free end side of the toner receiving member. Move the toner to the fulcrum side.

JP 2012-208469 A Japanese Patent Laying-Open No. 2014-6411

  When the toner receiving member is vibrated as in Patent Documents 1 and 2, the deposited toner is shaken off, and the toner dropped by the vibration of the toner receiving member is used again for development. However, most of the toner deposited on the toner receiving member is uncharged or reversely charged toner. Therefore, when the toner accumulated on the toner receiving member is shaken off and used again for development, a fogging image in which the background portion that should originally be whitened becomes black due to poor charging of the toner, or toner scattering to the outside of the developing device occurs. There was a risk.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a developing device that can prevent fogging images and toner scattering due to uncharged or reversely charged toner deposited on a toner receiving member with a simple configuration, and an image forming apparatus including the developing device. Objective.

  In order to achieve the above object, a first configuration of the present invention includes a developing roller, a toner supply roller, a regulating blade, a casing, a toner receiving support member, a toner receiving member, and vibration generating means. Development device. The developing roller is disposed to face the image carrier on which the electrostatic latent image is formed, and supplies toner to the image carrier in a region facing the image carrier. The toner supply roller is disposed to face the developing roller, and supplies toner to the developing roller in a region facing the developing roller. The regulating blade is disposed to face the toner supply roller at a predetermined interval. The casing houses a developing roller, a toner supply roller, and a regulating blade. The toner receiving support member is disposed in the casing and faces the developing roller or the toner supply roller between the regulating blade and the image carrier. The toner receiving member has a toner receiving surface that is disposed along the longitudinal direction of the toner receiving support member and has a downward gradient toward the toner supply roller that receives the toner falling from the developing roller. The vibration generating means vibrates the toner receiving member. On the upper surface of the toner receiving support member, an opening extending along substantially the entire area in the longitudinal direction of the toner receiving support member is formed so as to overlap the lower end edge of the toner receiving surface. Inside the toner receiving support member, there is provided a toner storing portion for storing the toner dropped from the opening due to the vibration of the toner receiving member.

  According to the first configuration of the present invention, the toner dropped on the toner receiving member slides down along the toner receiving member due to vibration, and the toner receiving support member enters the toner receiving support member from the opening formed on the upper surface of the toner receiving support member. And is stored in the toner storage unit. Therefore, toner accumulation on the top surface of the tip of the regulation blade is suppressed, so that toner deposited on the top surface of the tip of the regulation blade adheres to the magnetic brush of the magnetic roller during image formation and further adheres to the developing roller. The occurrence of dropping can be effectively suppressed. Further, since the uncharged toner and the reversely charged toner that have fallen on the toner receiving member are not reused for development, it is possible to prevent the occurrence of fogging images and toner scattering to the outside of the developing device.

Schematic configuration diagram of a color printer 100 provided with the developing devices 3a to 3d of the present invention Side surface sectional drawing of the developing device 3a which concerns on one Embodiment of this invention. The perspective view which looked at the toner receiving support member 35 used for the developing device 3a of this embodiment from the inside of the developing container 20. The perspective view which looked at the toner receiving member 37 which comprises the toner receiving support member 35 from the back surface side The perspective view which shows the internal structure of the vibration generator 40 with which the toner receiving member 37 is mounted | worn. Front view of vibration motor 43 Side view of the vibration motor 43 as seen from the side of the vibration weight 50 Side sectional view of the periphery of the toner receiving support member 35 of the developing device 3a of the present embodiment. Side sectional view showing the developing device 3a of the present invention in which the arrangement of the toner supply roller 30 and the developing roller 31 is reversed.

  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 on which developing devices 3a to 3d of the present invention are mounted. Here, a tandem color printer 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). 1, an intermediate transfer belt 8 that rotates in the clockwise direction 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. Thereafter, the toner image primarily transferred onto the intermediate transfer belt 8 is secondarily transferred onto a transfer paper P as an example of a recording medium by the action of the secondary transfer roller 9. Further, the transfer paper P onto which the toner image is secondarily transferred is discharged from the main body of the color printer 100 after the toner image is fixed in the fixing unit 13. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d in the counterclockwise direction in FIG.

  The transfer paper P on which the toner image is secondarily transferred is accommodated in a paper cassette 16 disposed at the lower part of the main body of the color printer 100, and the secondary transfer roller 9 via the paper feed roller 12a and the registration roller pair 12b. And the intermediate transfer belt 8 to be described later is conveyed to a nip portion with a 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. Further, a blade-like belt cleaner 19 for removing toner remaining on the surface of the intermediate transfer belt 8 is disposed on the downstream side of the secondary transfer roller 9.

  Next, the image forming units Pa to Pd will be described. Around and below the photosensitive drums 1a to 1d arranged to be rotatable, chargers 2a, 2b, 2c and 2d for charging the photosensitive drums 1a to 1d, and image information to each of the photosensitive drums 1a to 1d. 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. In addition, when the ratio of the toner in the two-component developer filled in each developing device 3a to 3d falls below a specified value due to the formation of a toner image described later, each developing device 3a to 3d is transferred from the toner container 4a to 4d. Toner is replenished. 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 rotation in the direction starts, the transfer paper P is conveyed from the registration roller pair 12b to the nip portion (secondary transfer nip portion) between the driving roller 11 and the secondary transfer roller 9 provided adjacent thereto at a predetermined timing. Then, the full color image on the intermediate transfer belt 8 is secondarily transferred onto the transfer paper P. The transfer sheet P on which the toner image is secondarily transferred is conveyed to the fixing unit 13.

  The transfer paper P conveyed to the fixing unit 13 is heated and pressed by the fixing roller pair 13a to fix the toner image on the surface of the transfer paper P, and 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 on only one side of the transfer paper P, it is discharged as it is onto the discharge tray 17 by the discharge roller pair 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 conveyed in the direction of the discharge roller pair 15. Then, after the trailing edge of the transfer paper P has passed through the branch portion 14, the discharge roller pair 15 is rotated in the reverse direction and the transport direction of the branch portion 14 is switched. As a result, the transfer paper P is distributed from the rear end to the paper transport path 18 and is transported again to the secondary transfer nip portion with the image surface reversed. Then, the next toner image formed on the intermediate transfer belt 8 is secondarily transferred to the surface of the transfer paper P on which the image is not formed by the secondary transfer roller 9. The transfer paper P onto which the toner image has been secondarily transferred is conveyed to the fixing unit 13 where the toner image is fixed and then discharged onto the discharge tray 17.

  FIG. 2 is a side sectional view of the developing device 3a according to the 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 3a is opposite to that in FIG. Further, in the following description, the developing device 3a disposed in the image forming unit Pa of FIG. 1 is illustrated, but the configuration of the developing devices 3b to 3d disposed in the image forming units Pb to Pd is basically the same. Therefore, explanation 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, and the developing container 20 is stirred and conveyed by a partition wall 20a. It is divided into a chamber 21 and a supply transfer chamber 22. 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.

  Then, the developer is agitated by the agitating / conveying screw 25a and the supply / conveying screw 25b and conveyed in the axial direction (perpendicular to the paper surface of FIG. 2) to pass 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. That is, a developer circulation path is formed in the developer container 20 by the agitating / conveying chamber 21, the supply / conveying chamber 22, and the developer passage.

  The developing container 20 extends obliquely upward to the right in FIG. 2. A toner supply 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 diagonally upward. 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 toner supply roller 30 and the developing roller 31 are shown in FIG. 2 rotates counterclockwise.

  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 toner supply roller 30 is composed of a non-magnetic rotating sleeve that rotates counterclockwise in FIG. 2 and a fixed magnet body having 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 that is fixed in the developing sleeve. It faces with a predetermined gap at the facing position (facing 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 toner supply roller 30 (perpendicular to the paper surface of FIG. 2), and the spike cutting blade 33 rotates in the rotation direction of the toner supply roller 30. In the counterclockwise direction in FIG. 2, the developing roller 31 and the toner supply roller 30 are positioned on the upstream side. A slight gap (gap) is formed between the tip of the ear cutting blade 33 and the surface of the toner supply 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 toner supply roller 30. ) And an alternating voltage (hereinafter referred to as Vmag (AC)). These DC voltage and AC voltage are applied from the developing bias power source to the developing roller 31 and the toner supply roller 30 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 toner supply roller 30. Then, a magnetic brush (not shown) is formed on the toner supply roller 30, and the layer thickness of the magnetic brush on the toner supply roller 30 is regulated by the ear cutting blade 33. Thereafter, the magnetic brush is conveyed to a portion where the toner supply roller 30 and the developing roller 31 face each other by the rotation of the toner supply roller 30, and Vmag (DC) applied to the toner supply roller 30 and Vslv ( A toner thin layer is formed on the developing roller 31 by a potential difference ΔV from the DC and a magnetic field.

  The thickness of the toner layer on the developing roller 31 varies depending on the resistance of the developer, the rotational speed difference between the toner supply roller 30 and the developing roller 31, and the like, 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 toner supply 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. The 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 toner that is not used for development and remains on the developing roller 31 is conveyed again to the opposite portion of the developing roller 31 and the toner supply roller 30 by the rotation of the developing roller 31 and is collected by the magnetic brush on the toner supply roller 30. The The magnetic brush is peeled off from the toner supply roller 30 at the same polarity portion of the fixed magnet body, and then falls into the supply conveyance chamber 22.

  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 toner supply roller 30 by the supply / conveyance screw 25 b to form a magnetic brush, and is conveyed to the ear cutting blade 33.

  A toner receiving and supporting member 35 having a triangular cross-section projecting inward of the developing container 20 is provided in the vicinity of the developing roller 31 on the right side wall of the developing container 20 in FIG. As shown in FIG. 2, the toner receiving support member 35 is disposed along the longitudinal direction of the developing container 20 (the direction perpendicular to the paper surface of FIG. 2). A wall portion that faces the developing roller 31 and is inclined downward from the developing roller 31 toward the toner supply roller 30 is configured. On the upper surface of the toner receiving support member 35, a toner receiving member 37 is attached along the longitudinal direction for receiving the toner that is peeled off from the developing roller 31 and falls.

  3 is a perspective view of the toner receiving support member 35 used in the developing device 3a of the present embodiment as viewed from the inside of the developing container 20 (left side in FIG. 2), and FIG. 4 is a toner constituting the toner receiving support member 35. 4 is a perspective view of the receiving member 37 as viewed from the inside of the toner receiving support member 35. FIG.

  The toner receiving support member 35 is attached to a resin supporting member main body 36, a sheet metal toner receiving member 37 that is swingably supported by the supporting member main body 36, and a substantially central portion in the longitudinal direction of the toner receiving member 37. Vibration generator 40 to be operated.

  On the upper surface of the support member main body 36, there is a slit-like opening 36 a that extends along substantially the entire longitudinal direction (left and right direction in FIG. 3) of the support member main body 36 so as to overlap the lower end edge of the toner receiving member 37. Is formed. Inside the support member main body 36, a storage unit 60 that stores the vibration generating device 40 when the toner receiving member 37 is mounted, and a toner that stores toner dropped from the surface of the toner receiving member 37 through the opening 36a. The storage part 61 (all refer FIG. 8) is formed.

  A film-like seal member 44 is provided at the upper end of the support member main body 36. The seal member 44 extends in the longitudinal direction of the support member main body 36 so that the front end thereof is in contact with the surface of the photosensitive drum 1a, so that the toner in the developing container 20 (see FIG. 2) does not leak to the outside. It has a function of shielding.

  The toner receiving member 37 has a flat plate shape and has a toner receiving surface 37a facing the developing roller 31 (see FIG. 2). An engagement portion 38 that engages a contact spring 48 that grounds (grounds) the toner receiving member 37 is formed on one end side of the toner receiving member 37 in the longitudinal direction. A lower end portion of the contact spring 48 contacts the spike cutting blade 33 (see FIG. 2) via a conductive spring receiving member (not shown). A holding portion 39 having a pair of holding claws 39 a that hold the vibration generating device 40 is formed at a substantially central portion in the longitudinal direction of the toner receiving member 37. A substrate 45 on which a circuit for controlling driving of the vibration motor 43 (see FIG. 6) and electronic components (not shown) are mounted is fixed to the vibration generator 40 by screws 46.

  A sheet member 41 is attached to the toner receiving surface 37 a of the toner receiving member 37. The sheet member 41 is formed of a material that prevents toner from adhering to the toner receiving member 37 in order to suppress toner adhesion to the toner receiving member 37. Examples of the material of the sheet member 41 include a fluororesin sheet.

  FIG. 5 is a perspective view of the vibration generator 40. 5 shows a state in which the substrate 45 (see FIG. 4) is removed from the motor mounting holder 42 so that the inside of the vibration generating device 40 can be seen. The vibration generator 40 includes a motor mounting holder 42 and a vibration motor 43, and the motor mounting holder 42 is formed with a motor holding portion 42 a for holding the vibration motor 43 and a screw hole 42 b for fastening a screw 46. A vibration weight 50 is fixed to the output shaft 43 a of the vibration motor 43. When the vibration generating device 40 is attached to the toner receiving member 37, the output shaft 43 a of the vibration motor 43 is fixed along the longitudinal direction of the toner receiving member 37. A lead wire (not shown) for supplying power to the vibration motor 43 is connected to the motor mounting holder 42.

  FIG. 6 is a front view of the vibration motor 43, and FIG. 7 is a side view of the vibration motor 43 as viewed from the side of the vibration weight 50. When seen from the direction of the output shaft 43a of the vibration motor 43 (the right direction in FIG. 6), the vibration weight 50 has a cam shape in which a notch 50a is formed in a part of the disk as shown in FIG. Thus, the shape is asymmetric with respect to the output shaft 43a. When the output shaft 43a rotates at a speed higher than a predetermined speed, the centrifugal force acting on the notch 50a is smaller than that of the other portions, so that an uneven centrifugal force is applied to the vibration weight 50. As the centrifugal force is transmitted to the output shaft 43a, the vibration motor 43 vibrates. The shape of the vibration weight 50 is not limited to a cam shape, and may be an arbitrary shape that shifts the center of gravity with respect to the output shaft 43a.

  FIG. 8 is a side cross-sectional view showing the structure around the toner receiving support member 35 in the developing device 3a of this embodiment. 8 shows a cross section of the toner receiving support member 35 in the vicinity of the vibration motor 43 (cross section taken along the line XX ′ in FIG. 3).

  As shown in FIG. 8, the toner receiving member 37 is supported by the support member main body 36 via the vibration generator 40 at a substantially central portion in the longitudinal direction of the toner receiving surface 37 a (direction perpendicular to the paper surface of FIG. 8). Yes. The toner receiving member 37 is supported by the support member main body 36 on the side (left end in FIG. 8) close to the toner supply roller 31 in the width direction (left and right direction in FIG. 8) of the toner receiving surface 37a, and on the opposite side (FIG. 8). Is the free end. The toner receiving member 37 is disposed so that the toner receiving surface 37a is inclined downward from the photosensitive drum 1a toward the toner supply roller 30. Further, the vibration motor 43 is disposed so that the output shaft 43 a is substantially parallel to the longitudinal direction of the toner receiving member 37.

  Further, the sheet member 41 covers substantially the entire area of the toner receiving surface 37a including the boundary between the support member main body 36 and the toner receiving member 37 on the seal member 44 side, the engaging portion 38, and the holding portion 39 (see FIG. 4). Is pasted. The sheet member 41 prevents the toner from adhering to the toner receiving surface 37a and prevents the toner from entering the motor mounting holder 42 and the malfunction of the vibration motor 43 due to the toner entering.

  By rotating the output shaft 43a at high speed (for example, about 10,000 rpm) during non-image formation, the vibration weight 50 also rotates at high speed together with the output shaft 43a. At this time, since an uneven centrifugal force is applied to the vibration weight 50, the vibration generator 40 including the vibration motor 43 and the motor mounting holder 42 vibrates via the output shaft 43a. The toner receiving member 37 to which the vibration generating device 40 is attached also vibrates.

  In the present embodiment, the output shaft 43a of the vibration motor 43 is arranged such that the outer peripheral surface of the output shaft 43a facing the toner receiving member 37 is a fulcrum (the right end in FIG. 8) from the free end of the toner receiving member 37 (FIG. 8). It is rotated in the direction of moving toward the left end (counterclockwise direction in FIG. 8). By rotating the output shaft 43a in this direction, the toner receiving member 37 vibrates so as to move the toner accumulated on the toner receiving surface 37a from the free end side (upper end side) to the fulcrum side (lower end side).

  On the other hand, when the output shaft 43a is rotated in the reverse direction (clockwise direction in FIG. 8), the toner is moved so as to rise from the fulcrum side to the free end side due to the vibration of the toner receiving member 37. The toner deposited on the receiving surface 37a does not slide down. Therefore, by rotating the output shaft 43a of the vibration motor 43 as in the present embodiment, the toner deposited on the toner receiving surface 37a can be effectively slid down along a downward gradient.

  Due to the vibration of the toner receiving surface 37a, as shown in FIG. 8, the toner T deposited on the toner receiving surface 37a slides downward (in the direction of the white arrow in FIG. 8) along the inclination of the toner receiving surface 37a. Then, the toner T that has slid down along the toner receiving surface 37 a falls into the support member main body 36 from the opening 36 a formed along the lower edge of the toner receiving member 37, and is stored in the toner storage portion 61. The The capacity of the toner storage unit 61 is designed so that a sufficient toner storage space remains even when the useful life of the developing device 3a expires.

  In the present embodiment, a toner storage unit 61 that stores toner dropped from the opening 36 a is provided inside the support member main body 36 that constitutes the toner receiving support member 35. The toner reservoir 61 is formed over substantially the entire length of the support member main body 36 in the longitudinal direction (direction perpendicular to the paper surface of FIG. 8). As a result, uncharged or reversely charged toner deposited on the toner receiving surface 37 a of the toner receiving member 37 is collected in the toner storage unit 61 without being returned into the supply transport chamber 22. Accordingly, it is possible to effectively suppress the occurrence of toner scattering and fogging image due to the use of uncharged or reversely charged toner for development. Further, since the toner storage unit 61 is partitioned from the storage unit 60 in which the vibration generating device 40 is stored inside the support member main body 36, the toner collected in the toner storage unit 61 enters the motor mounting holder 42. There is no risk.

  In the present embodiment, the toner that has slipped along the toner receiving surface 37 a does not fall on the top surface of the tip end of the ear cutting blade 33, and therefore, the toner deposited on the top surface of the tip end of the ear cutting blade 33 is returned to the supply conveyance chamber 22. In addition, it is not necessary to rotate the toner supply roller 30 in the reverse direction (clockwise direction in FIG. 8) during image formation during non-image formation. Therefore, it is not necessary to reversely rotate the agitating / conveying screw 25a and the supply / conveying screw 25b, and the developer overflows from the toner replenishing port or the developer is biased in the developing container 20 to generate noise in the toner concentration sensor. Can be prevented.

  The timing at which the toner receiving member 37 is vibrated may be set every time the printing operation is completed, or may be a predetermined time such as when the number of printed sheets reaches a predetermined number or when the temperature in the developing device 3a becomes equal to or higher than a predetermined number. It may be performed at the timing. By vibrating the toner receiving member 37 every time the predetermined number of printed sheets is reached, the vibration of the toner receiving member is automatically executed according to the number of printed sheets. Therefore, it is not necessary for the user himself to manually set the vibration of the toner receiving member 37, and it is possible to avoid setting mistakes, forgetting to set, or unnecessary vibration.

  In the present embodiment, the toner that has slid down along the toner receiving surface 37 a is collected in the toner storage unit 61, so that it accumulates on the upper surface of the ear cutting blade 33 or adheres to the outer peripheral surface of the toner supply roller 31. do not do. Therefore, even if the toner receiving member 37 is vibrated during image formation, there is no possibility of toner dropping. That is, the developing devices 3a to 3d according to the present embodiment vibrate the toner receiving member 37 at an arbitrary timing regardless of whether the image is formed or not, and the toner receiving surface 37a receives toner. Deposition 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 shape and configuration of the toner receiving support member 35 and the toner receiving member 37 shown in the above embodiment are merely examples, and are not particularly limited to the above embodiment, and these are appropriately set according to the apparatus configuration and the like. be able to.

  For example, in the above-described embodiment, the capacity of the toner storage unit 61 is set so that a sufficient toner storage space remains even when the developing devices 3 a to 3 d expire. However, the toner storage unit 61 is connected to the support member main body 36. It may be configured as a separate member and replaceable. Further, the toner storage unit 61 is a collection container that collects waste toner removed by the cleaning units 7a to 7d and the belt cleaner 19 (see FIG. 1), or floating toner that is sucked by a duct from the developing devices 3a to 3d. The toner stored in the toner storage unit 61 may be transported to the recovery container using a transport screw or the like.

  In the above-described embodiment, the present invention uses a two-component developer, forms a magnetic brush on the toner supply roller 30, moves only the toner from the toner supply roller 30 to the development roller 31, and performs photosensitivity from the development roller 31. Although the present invention is applied to the developing devices 3a to 3d for supplying the toner to the body drums 1a to 1d, as shown in FIG. 9, the development roller 31 and the toner supply roller 30 are arranged opposite to those in the above embodiment. Toner is supplied to the photosensitive drums 1a to 1d by a magnetic brush made of a two-component developer held on the surface of a roller 31 (in this configuration, a magnetic roller having the same configuration as the toner supply roller 30 of the above embodiment). The toner supply roller 30 is held on the surface of the toner supply roller 30 (in this configuration, the configuration is the same as the developing roller 31 of the above embodiment). It supplies the toner to the developing roller 31, to a developing device for collecting the surplus toner of the developing roller 31 surface with a toner supply roller 30 can be applied. Also in this configuration, it is possible to effectively suppress the toner that has fallen from the developing roller 31 from being accumulated around the ear cutting blade 33 that faces the toner supply roller 30. Hereinafter, the effects of the present invention will be described more specifically with reference to examples.

  The toner receiving support member 35 is provided with an opening 36a and a toner reservoir 61, and the toner falling from the toner receiving surface 37a is stored in the toner reservoir 61. The developing devices 3a to 3d of the present embodiment (the present invention) and the opening Using the developing devices 3a to 3d (comparative example) 36a and the toner storage unit 61, the occurrence of the fog image and toner scattering was investigated. As a testing method, the developing devices 3a to 3d of the present invention and comparative examples are mounted on a testing machine (TASKalfa 7551ci, manufactured by Kyocera Document Solutions), and vibration occurs every 500 sheets of printing while changing the printing rate and the usage environment of the device. The generation of fogged images and toner scattering was evaluated when the toner receiving member 37 was vibrated by the motor 43 to perform 100,000 durable printing.

  The process speed of the color printer 100 is 25 sheets / minute, the rotational speed of the photosensitive drums 1a to 1d is 210 mm / second, the drum surface potential (bright potential) V0 = + 430V, the image portion potential (dark potential) VL = + 100V, The peripheral speed ratio of the developing roller 31 to the photosensitive drums 1a to 1d is 1.5 (with rotation), the peripheral speed ratio of the toner supply roller 30 to the developing roller 31 is 1.2 (counter rotation), and between the drum and the developing roller The gap was 0.12 mm, and the gap between the developing roller and the toner supply roller was 0.3 mm.

The developing roller 31 is made of alumite-treated surface and laminated with a resin coating layer. The DC component Vslv (DC) = 50 V and the AC component Vslv (AC) (Vpp = 1500 V, frequency 3.7 kHz, duty ratio 27%). ) And a bias in which an AC component Vmag (AC) (Vpp = 2200 V, frequency 4.7 kHz, Duty ratio 68%) is superimposed on the DC component Vmag (DC) = 350 V. Was applied. Further, a positively chargeable toner having an average particle diameter of 6.8 μm was used as the toner, and a coated ferrite carrier having a volume resistivity of 10 ¹⁰ Ωcm, a saturation magnetization of 65 eum / g, and an average particle diameter of 35 μm was used as the carrier.

The toner receiving member 37 was manufactured using a stainless steel plate having a length of 317 mm, a width of the toner receiving surface 37a of 12.7 mm, and a thickness of 0.1 mm. The vibration motor 43 uses a motor with a rated rotational speed of 10000 ± 3000 rpm, a rated voltage of 3.0 V (rated voltage range of 2.6 to 3.6 V), a rated current of 160 mA, and a starting current of 175 mA. A weight of a semi-cylindrical tungsten alloy having a semicircular bottom with a corner of 150 ° and a length of 3.6 mm (volume 42.39 mm ³ , mass 0.838 g) was fixed.

  The method for evaluating a fog image is to measure a fog density (FD, Fog Density) of an image printed using a reflection densitometer (RD918, manufactured by Macbeth Co.), and when the FD in a white background portion is 0.01 or more, the fog image Yes. The toner scattering evaluation method is to visually check the presence or absence of toner scattering to the outside of the developing device, ○ when no toner scattering is observed, Δ when slight toner scattering is observed, and toner scattering is remarkable. When it was recognized, it was set as x. The results are shown in Tables 1 and 2.

※；Ｈ／Ｈ：高温高湿環境（３２．５℃、８０％）、Ｎ／Ｎ：常温常湿環境（２３℃、５０％）、Ｌ／Ｌ：低温低湿環境（１０℃、１０％）

*: H / H: High temperature and high humidity environment (32.5 ° C, 80%), N / N: Normal temperature and normal humidity environment (23 ° C, 50%), L / L: Low temperature and low humidity environment (10 ° C, 10%)

  As shown in Table 1, in the developing devices 3a to 3d of the present invention, fog images and toner scattering did not occur from the beginning to the end of the durability period, regardless of the use environment and the printing rate.

  On the other hand, as shown in Table 2, in the developing devices 3a to 3d of the comparative examples, fogged images and toner scattering occurred regardless of the printing rate in a high temperature and high humidity environment. Further, even under a normal temperature and normal humidity environment and a low temperature and low humidity environment, fog images and toner scattering occurred when the printing rate was high and the number of printed sheets was large.

  From the above results, the toner accumulated on the toner receiving surface 37a of the toner receiving member 37 is stored in the toner storage unit 61 without returning to the supply conveyance chamber 22, so that the fog image and toner scattering can be effectively suppressed. confirmed.

  The present invention can be used in a developing device having a toner receiving member that faces the developing roller between a region where the image carrier and the developing roller face each other and the regulating blade. By utilizing the present invention, it is possible to provide a developing device and an image forming apparatus including the same that can prevent fogging images and toner scattering due to uncharged or reversely charged toner deposited on the toner receiving member with a simple configuration.

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 Partition wall 30 Toner supply roller 31 Development roller 33 Ear cutting blade (regulating blade)
35 toner receiving support member 35a tip portion 36 support member body 36a opening 37 toner receiving member 37a toner receiving surface 40 vibration generating device (vibration generating means)
41 Sheet member 42 Motor mounting holder 43 Vibration motor 43a Output shaft 50 Excitation weight 60 Storage unit 61 Toner storage unit 100 Color printer (image forming apparatus)

Claims (8)

A developing roller that is disposed to face an image carrier on which an electrostatic latent image is formed, and that supplies toner to the image carrier in a region facing the image carrier;
A toner supply roller that is disposed to face the developing roller and supplies toner to the developing roller in a region facing the developing roller;
A regulating blade disposed opposite to the toner supply roller at a predetermined interval;
A casing that houses the developing roller, the toner supply roller, and the regulating blade;
A toner receiving support member disposed in the casing and facing the developing roller or the toner supply roller between the regulating blade and the image carrier;
A toner receiving member that is disposed along the longitudinal direction of the toner receiving support member and has a toner receiving surface that is inclined downward toward the toner supply roller that receives toner falling from the developing roller;
Vibration generating means for vibrating the toner receiving member;
In a developing device comprising:
On the upper surface of the toner receiving support member, an opening extending substantially along the entire length of the toner receiving support member is formed so as to overlap the lower end edge of the toner receiving surface.
The developing device according to claim 1, further comprising: a toner storage unit configured to store toner dropped from the opening due to the vibration of the toner receiving member.   2. The toner receiving support member according to claim 1, wherein a storage unit that stores the vibration generating unit is provided inside the toner receiving support member, and the toner storage unit is provided separately from the storage unit. Development device.   The vibration generating unit includes a vibration motor fixed to a back surface of the toner receiving member, and an excitation weight fixed so that a center of gravity is shifted with respect to an output shaft of the vibration motor. The developing device according to claim 1 or 2. The vibration motor is fixed to a back surface of the toner receiving member so that an output shaft is substantially parallel to a longitudinal direction of the toner receiving member,
The output shaft is rotated in a direction in which an outer peripheral surface of the output shaft of the vibration motor facing the toner receiving member moves toward a fulcrum of the toner receiving member on the toner supply roller side. The developing device according to claim 3.   The developing device according to claim 1, wherein a sheet member having a toner adhesion strength weaker than that of the toner receiving member is attached to the toner receiving surface.   8. The toner roller according to claim 1, wherein the toner supply roller is a magnetic roller that carries a two-component developer including toner and carrier by a plurality of magnetic poles provided inside. Development device.   7. The development according to claim 1, wherein the developing roller is a magnetic roller that carries a two-component developer including a toner and a carrier by a plurality of magnetic poles provided therein. apparatus.   An image forming apparatus comprising the developing device according to claim 1.

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