JP7073738B2 - A developing device and an image forming device equipped with it - Google Patents

Description

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

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

In recent years, with the progress of color printing and high-speed processing, the configuration of the image forming apparatus has become complicated, and the toner stirring member in the developing device has to be rotated at high speed in order to cope with the high-speed processing. In particular, in a developing method using a two-component developer containing a magnetic carrier and a toner and using a magnetic roller (toner supply roller) for supporting the developer and a developing roller for supporting only the toner, the developing roller and the magnetic roller are used. At the opposite portion, only the toner is supported on the developing roller by the magnetic brush formed on the magnetic roller, and the toner not used for development is peeled off from the developing roller. Therefore, toner is likely to scatter in the vicinity of the facing portion between the developing roller and the magnetic roller, and the toner floating in the developing device is deposited around the spike cutting blade (regulatory blade), and the accumulated toner is aggregated. If it adheres to the developing roller, toner may fall off and image defects may occur.

Therefore, for example, Patent Document 1 describes a developing roller or magnetic in a developing apparatus using a two-component developer containing a magnetic carrier and toner, a magnetic roller carrying the developer, and a developing roller carrying only the toner. Development provided with a toner receiving support member facing the roller, a toner receiving member arranged along the longitudinal direction of the toner receiving support member and receiving toner falling from the developing roller, and a vibration generating means for vibrating the toner receiving member. The device is disclosed.

According to the above configuration, by shaking off the toner accumulated on the toner receiving member by vibration, it is possible to suppress the accumulation of toner around the regulation blade in the casing of the developing apparatus and the occurrence of toner dropping due to the accumulation. ..

Japanese Unexamined Patent Publication No. 2012-208469

In the configuration of Patent Document 1, the deposited toner on the toner receiving member is returned to the casing of the developing apparatus by vibration and used again for development. However, the deposited toner is scattered toner in the developing device, and the amount of charge is unstable. Therefore, if the deposited toner moves from the magnetic roller to the developing roller and is used for development, there is a possibility that an image defect such as a fog image may occur. Further, after the deposited toner is collected in the casing, it is necessary to take a long aging time in order to sufficiently mix it with the developer in the casing to stabilize the charge amount, which causes a problem that the image formation efficiency is lowered. rice field.

In view of the above problems, the present invention is a developing apparatus capable of recovering toner accumulated around the blade into a developing agent in a casing and discharging a developing agent containing the recovered toner, and an image forming apparatus including the same. The purpose is to provide.

In order to achieve the above object, the first configuration of the present invention includes a developing container, a first stirring and transporting member, a second stirring and transporting member, a developer supply port, a developer discharge unit, a developing roller, and the like. It is a developing device including a toner supply roller, a regulation blade, a toner receiving member, and a vibration generator. The developing container includes a first transport chamber, a second transport chamber arranged in parallel with the first transport chamber with the partition portion interposed therebetween, and a first transport chamber and the second transport chamber on both ends in the longitudinal direction of the partition portion. It has a communication section that allows the chambers to communicate with each other, and houses a two-component developer containing a carrier and toner. The first stirring and transporting member stirs and transports the developer in the first transport chamber in the direction of the rotation axis. The second stirring and transporting member stirs and transports the developer in the second transporting chamber in the direction opposite to that of the first stirring member. The developer supply port replenishes the developer in the developing container. The developer discharging unit discharges excess developer from the developing container. The developing roller is rotatably supported in the developing container and supplies toner to the image carrier in a region facing the image carrier on which the electrostatic latent image is formed. The toner supply roller is rotatably supported by the developing container, supports the developer in the second transport chamber on the surface, and supplies toner to the developing roller in a region facing the developing roller. The regulating blades are arranged to face the toner supply rollers at predetermined intervals. The toner receiving member is arranged so as to face the developing roller or the toner supply roller between the regulating blade and the image carrier in the developing container, and receives the toner falling from the developing roller. The vibration generator vibrates the toner receiving member. The developing device vibrates the toner receiving member by the vibration generator at the time of non-image formation to shake off the toner accumulated on the toner receiving member, and collects the toner in the second transport chamber. It is possible to execute a forced discharge mode in which the developer containing the recovered toner collected in the transport chamber is forcibly discharged from the developer discharge unit to the outside of the developing container.

According to the first configuration of the present invention, by executing the forced discharge mode after the toner recovery mode, the recovered toner is returned to the second transport chamber without waiting for the bulk of the developer due to the replenishment of the new developer. It is possible to efficiently discharge a part of the developer containing the recovered toner having an unstable charge amount according to the timing. Therefore, it is possible to effectively suppress fog images and toner scattering due to poor charging of the toner in the developer.

Schematic block diagram of a color printer 100 equipped with the developing devices 3a to 3d of the present invention. Side sectional view of the developing apparatus 3a according to the first embodiment of the present invention. A plan sectional view showing the configuration of the stirring unit of the developing apparatus 3a of the first embodiment. Perspective view of the toner receiving support member 35 used in the developing apparatus 3a of the first embodiment as viewed from the inside of the developing container 20. Perspective view of the toner receiving member 37 constituting the toner receiving support member 35 as viewed from the back surface side. A perspective view showing the internal structure of the vibration generator 40 mounted on the toner receiving member 37. It is a side sectional view around the toner receiving support member 35 of the developing apparatus 3a of 1st Embodiment, and is the figure which shows the sectional view around the vibration motor 43. Partially enlarged view of the toner receiving support member 35 in FIG. A plan sectional view showing a stirring unit when the developer discharging mode is executed in the developing apparatus 3a of the first embodiment. A plan sectional view showing the structure of the stirring unit of the developing apparatus 3a according to the second embodiment of the present invention. A plan sectional view of a stirring unit when the forced discharge mode is executed in the developing apparatus 3a of the second embodiment. A plan sectional view of the stirring portion when the forced discharge mode is executed in the developing apparatus 3a of the modified example of the second embodiment.

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 according to an embodiment of the present invention, and here shows a tandem color printer. In the main body of the color printer 100, four image forming portions Pa, Pb, Pc and Pd are arranged in order from the upstream side in the transport direction (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 are cyan, magenta, and yellow, respectively, depending on each step of charging, exposure, development, and transfer. And black images are formed sequentially.

Photoreceptor drums 1a, 1b, 1c and 1d carrying visible images (toner images) of each color are disposed on these image forming portions Pa to Pd, respectively, and are further rotated clockwise in FIG. An intermediate transfer belt 8 is provided adjacent to each image forming portion Pa to Pd.

When image data is input from a host device such as a personal computer, first, the surfaces of the photoconductor drums 1a to 1d are uniformly charged by the charging devices 2a to 2d. Next, the exposure apparatus 5 irradiates light according to the image data to form an electrostatic latent image corresponding to the image data on the photoconductor drums 1a to 1d. The developing devices 3a to 3d are filled with a predetermined amount of a two-component developer (hereinafter, also simply referred to as a developing agent) containing toners of each color of cyan, magenta, yellow and black by the toner containers 4a to 4d. The toner in the developer is supplied onto the photoconductor drums 1a to 1d by 3a to 3d and adheres electrostatically. As a result, a toner image corresponding to the electrostatic latent image formed by the exposure from the exposure apparatus 5 is formed.

Then, an electric field is applied between the primary transfer rollers 6a to 6d and the photoconductor drums 1a to 1d at a predetermined transfer voltage by the primary transfer rollers 6a to 6d, and cyan, magenta, yellow and cyanide, magenta, yellow and cyanide on the photoconductor drums 1a to 1d are applied. The black toner image is primarily transferred onto the intermediate transfer belt 8. Toner and the like remaining on the surfaces of the photoconductor drums 1a to 1d after the primary transfer are removed by the cleaning devices 7a to 7d.

The transfer paper P on which the toner image is transferred is housed in a paper cassette 16 arranged in the lower part of the image forming apparatus 100, and the transfer paper P is predetermined via the paper feed roller 12a and the resist roller pair 12b. It is conveyed to the secondary transfer roller 9 provided adjacent to the intermediate transfer belt 8 and the nip portion (secondary transfer nip portion) of the intermediate transfer belt 8 at the timing. The transfer paper P on which the toner image is secondarily transferred is conveyed to the fixing portion 13.

The transfer paper P conveyed to the fixing portion 13 is heated and pressurized 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 discharged to the discharge tray 17 as it is (or after being distributed to the reverse transfer path 18 by the branch portion 14 and the images are formed on both sides) by the discharge roller pair 15.

FIG. 2 is a side sectional view of the developing apparatus 3a according to the first embodiment of the present invention mounted on the color printer 100. Note that FIG. 2 shows a state seen from the back surface side of FIG. 1, and the arrangement of each member in the developing apparatus 3a is reversed left and right from FIG. Further, in the following description, the developing device 3a arranged in the image forming unit Pa of FIG. 1 is exemplified, but the configuration of the developing devices 3b to 3d arranged in the image forming units Pb to Pd is basically the same. Therefore, the description is omitted.

As shown in FIG. 2, the developing apparatus 3a includes a developing container (casing) 20 in which a two-component developing agent (hereinafter, simply referred to as a developing agent) composed of a toner and a magnetic carrier is housed, and the developing container 20 is provided. It is divided into a stirring transfer chamber 20b and a supply transfer chamber 20c by a partition wall 20a. In the stirring and transporting chamber 20b and the supply and transporting chamber 20c, a stirring and transporting screw 25 for mixing and stirring the toner (positively charged toner) supplied from the toner container 4a (see FIG. 1) with the carrier and charging the toner, and the feeding and transporting screw 25. Each screw 26 is rotatably arranged.

Then, the developer is conveyed in the axial direction (direction perpendicular to the paper surface in FIG. 2) while being agitated by the stirring transfer screw 25 and the supply transfer screw 26, and the developer passage paths formed at both ends of the partition wall 20a (FIG. 2). 3) is circulated between the stirring and transporting chamber 20b and the supply and transporting chamber 20c. That is, a circulation path for the developer is formed in the developing container 20 by the stirring transfer chamber 20b, the supply transfer chamber 20c, and the developer passage path.

The developing container 20 extends diagonally upward to the right in FIG. 2, a toner supply roller 30 is arranged above the supply transfer screw 26 in the developing container 20, and a developing roller is diagonally upward to the right of the toner supply roller 30. 31 are arranged facing each other. The developing roller 31 faces the photoconductor drum 1a on the opening side (right side of FIG. 2) of the developing container 20, and the toner supply roller 30 and the developing roller 31 are counterclockwise in FIG. 2 with respect to their respective rotation axes. Rotate in the direction.

In the stirring transfer chamber 20b, a toner concentration sensor 28 is arranged facing the stirring transfer screw 25. The toner concentration sensor 28 detects the ratio (T / C) of toner to carriers in the developing agent. For example, a magnetic permeability sensor that detects the magnetic permeability of the developing agent in the developing container 20 is used. In the present embodiment, the toner concentration sensor 28 detects the magnetic permeability of the developer, and the voltage value corresponding to the detection result is output to a control unit (not shown) described later by the control unit. The toner concentration is determined from the output value of the toner concentration sensor 28. The control unit transmits a control signal to the developer replenishment motor (not shown) according to the determined toner concentration, and from the toner container 4a to the stirring transfer chamber 20b via the developer replenishment port 20f (see FIG. 3). A predetermined amount of toner and carrier is replenished.

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 is composed of a cylindrical developing sleeve that rotates counterclockwise in FIG. 2 and a developing roller side magnetic pole fixed in the developing sleeve. The toner supply roller 30 and the developing roller 31 are the same. They face each other with a predetermined gap at the facing position (opposing 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 panicle cutting blade 33 is attached to the developing container 20 along the longitudinal direction of the toner supply roller 30 (direction perpendicular to the paper surface in FIG. 2), and the panicle cutting blade 33 is in the rotation direction of the toner supply roller 30. In (counterclockwise direction of FIG. 2), the developing roller 31 and the toner supply roller 30 are positioned upstream of the facing positions. A slight 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 AC voltage (hereinafter referred to as Vmag (AC)) are applied. These DC voltage and AC voltage are applied to the developing roller 31 and the toner supply roller 30 from the developing bias power supply via a bias control circuit (neither is shown).

As described above, the toner is charged by circulating the stirring transfer chamber 20b and the supply transfer chamber 20c in the developing container 20 while the developer is being stirred by the stirring transfer screw 25 and the supply transfer screw 26, and the toner is charged by the supply transfer screw 26. 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 after the layer thickness of the magnetic brush on the toner supply roller 30 is regulated by the spike cutting blade 33, the toner supply roller 30 and the developing roller 31 are combined. A toner thin layer is formed on the developing roller 31 by a potential difference ΔV between Vmag (DC) applied to the toner supply roller 30 and Vslv (DC) applied to the developing roller 31, and a magnetic field, which are conveyed to the facing portions.

The toner layer thickness on the developing roller 31 varies depending on the resistance of the developer, the difference in rotation speed between the toner supply roller 30 and the developing roller 31, and the like, but can be controlled by ΔV. Increasing ΔV makes the toner layer on the developing roller 31 thicker, and decreasing ΔV makes it thinner. Generally, the range of ΔV at the time of development is 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 the facing portion (opposing region) between the photoconductor drum 1a and the developing roller 31 by the rotation of the developing roller 31. Toner. Since Vslv (DC) and Vslv (AC) are applied to the developing roller 31, the toner flies due to the potential difference between the developing roller 31 and the photoconductor drum 1a, and the electrostatic latent image on the photoconductor drum 1a is developed. ..

The toner remaining not used for development is conveyed to the facing portion between the developing roller 31 and the toner supply roller 30 again, and is collected by the magnetic brush on the toner supply roller 30. Then, the magnetic brush is peeled off from the toner supply roller 30 at the same electrode portion of the fixed magnet body, and then falls into the supply transport chamber 20c.

After that, a predetermined amount of the developer is replenished from the developer supply port 20f (see FIG. 3) based on the detection result of the toner concentration sensor 28, and the appropriate toner is replenished while circulating in the supply transport chamber 20c and the stirring transport chamber 20b. It is a two-component developer that is uniformly charged at a concentration. This developer is again supplied onto the toner supply roller 30 by the supply transfer screw 26 to form a magnetic brush, and is transferred to the panicle cutting blade 33.

On the right side wall of FIG. 2 in the developing container 20, a toner receiving support member 35 having a triangular cross section is provided in the vicinity of the developing roller 31 so as to project inside the developing container 20. As shown in FIG. 2, the toner receiving support member 35 is arranged along the longitudinal direction of the developing container 20 (the direction perpendicular to the paper surface of FIG. 2), and the upper surface of the toner receiving support member 35 is the toner supply roller 30 and the toner supply roller 30. It faces the developing roller 31 and constitutes a wall portion that inclines downward from the developing roller 31 toward the toner supply roller 30. A toner receiving member 37 that receives toner that is peeled off from the developing roller 31 and drops is attached to the upper surface of the toner receiving support member 35 along the longitudinal direction.

FIG. 3 is a plan sectional view (XX'arrow cross-sectional view of FIG. 2) showing a stirring portion of the developing apparatus 3a of the first embodiment. As described above, the developing container 20 is formed with a stirring and transporting chamber 20b, a supply and transporting chamber 20c, a partition wall 20a, an upstream communication portion 20d, and a downstream communication portion 20e. A mouth 20f, a first developer discharging portion 20g, an upstream side wall portion 20h, and a downstream side wall portion 20i are formed. In the stirring transfer chamber 20b, the left side of FIG. 3 is the upstream side and the right side of FIG. 3 is the downstream side, and in the supply transfer chamber 20c, the right side of FIG. 3 is the upstream side and the left side of FIG. 3 is the downstream side. .. Therefore, the communication portion and the side wall portion are referred to as upstream and downstream with reference to the supply / transport chamber 20c.

The partition wall 20a extends in the longitudinal direction of the developing container 20 and partitions the stirring transfer chamber 20b and the supply transfer chamber 20c in parallel. The right end of the partition wall 20a in the longitudinal direction forms the upstream communication portion 20d together with the inner wall portion of the upstream side wall portion 20h, while the left end portion of the partition wall 20a in the longitudinal direction forms the inner wall portion of the downstream side wall portion 20i. Along with this, a downstream communication portion 20e is formed. The developing agent sequentially passes through the stirring transfer chamber 20b, the upstream communication section 20d, the supply transfer chamber 20c, and the downstream communication section 20e, and circulates in the developing container 20.

The developer supply port 20f is an opening for replenishing new toner and carriers into the developing container 20 from the toner container 4a (see FIG. 1) provided at the upper part of the developing container 20, and is upstream of the stirring transfer chamber 20b. It is arranged on the side (left side in FIG. 3).

The first developer discharging unit 20g is a part for discharging the developer surplus in the stirring transport chamber 20b and the supply transport chamber 20c due to the supply of toner and the carrier, and is supplied on the downstream side of the supply transport chamber 20c. It is a pipe-shaped transport path provided continuously in a cylindrical shape in the longitudinal direction of the transport chamber 20c.

The stirring transfer screw 25 arranged in the stirring transfer chamber 20b is provided integrally with the rotating shaft 25b and the rotating shaft 25b, and is formed spirally at a constant pitch in the axial direction of the rotating shaft 25b. It has 25a and 25a. Further, the first spiral blade 25a extends to both ends in the longitudinal direction of the stirring and transporting chamber 20b, and is provided so as to face the upstream side and downstream side communication portions 20d and 20e. The rotary shaft 25b is rotatably supported by the upstream side wall portion 20h and the downstream side wall portion 20i of the developing container 20.

The supply transfer screw 26 arranged in the supply transfer chamber 20c is provided integrally with the rotary shaft 26b and the rotary shaft 26b, and the first spiral blade 25a is provided in the axial direction of the rotary shaft 26b at the same pitch as the first spiral blade 25a. It has a second spiral blade 26a formed in a spiral shape by blades facing in the opposite direction to the above (opposite phase). Further, the second spiral blade 26a has a length equal to or longer than the axial length of the magnetic roller 21, and is further extended to a position facing the upstream communication portion 20d. The rotation shaft 26b is arranged in parallel with the rotation shaft 25b, and is rotatably supported by the upstream side wall portion 20h and the downstream side wall portion 20i of the developing container 20.

Further, the rotary shaft 26b is integrally provided with a deceleration transport unit 51, a regulation unit 52, and a discharge blade 53 together with the second spiral blade 26a.

The deceleration transfer unit 51 is formed in a spiral shape with a plurality of (here, three) blades facing in the same direction as the second spiral blade 26a. The spiral blades constituting the deceleration transfer unit 51 are set to have the same size as the outer diameter of the second spiral blade 26a and smaller than the pitch of the second spiral blade 26a.

The regulating unit 52 blocks the developer conveyed to the downstream side in the supply transport chamber 20c, and conveys the developer having a predetermined amount or more to the first developer discharge unit 20 g. The restricting portion 52 is composed of a spiral blade provided on the rotating shaft 26b, is formed in a spiral shape with blades facing in the opposite direction (opposite phase) to the second spiral blade 26a, and has an outer diameter of the second spiral blade 26a. It is substantially the same and is set smaller than the pitch of the second spiral blade 26a. Further, the regulating portion 52 forms a predetermined amount of gap between the inner wall portion of the developing container 20 such as the downstream side wall portion 20i and the outer peripheral portion of the regulating portion 52. Excess developer is discharged from this gap.

A discharge blade 53 is provided on the rotary shaft 26b in the first developer discharge unit 20 g. The discharge blade 53 is composed of a spiral blade facing the same direction as the second spiral blade 26a, but has a smaller pitch than the second spiral blade 26a and a smaller outer circumference of the blade. Therefore, when the rotary shaft 26b rotates, the discharge blade 53 also rotates, and the surplus developer that has passed over the regulating section 52 and is conveyed into the first developer discharge section 20 g is sent to the left side of FIG. 3 and is sent to the developing container. 20 It is designed to be discharged to the outside. The discharge blade 53, the regulating portion 52, and the second spiral blade 26a are integrally molded with the rotating shaft 26b by a synthetic resin. Further, a discharge port 65 communicating with a waste toner transfer pipe (not shown) is formed below the first developer discharge unit 20 g.

Gears 61 to 64 are arranged on the outer wall of the developing container 20. The gears 61 and 62 are fixed to the rotating shaft 25b, and the gear 64 is fixed to the rotating shaft 26b. The gear 63 is rotatably held in the developing container 20 and meshes with the gears 62 and 64. A clutch is built in the gear 63, and the stirring transfer screw 25 and the supply transfer screw 26 can be driven separately.

At the time of development in which the developer is not newly replenished, the developer is stirred and stirred from the stirring transfer chamber 20b while circulating with the upstream communication section 20d, the supply transfer chamber 20c, and the downstream communication section 20e. The developer is supplied to the toner supply roller 30.

When the toner is consumed by the development, the developer containing the toner and the carrier is replenished from the developer supply port 20f into the stirring transfer chamber 20b. The replenished developer is conveyed in the stirring transfer chamber 20b in the direction of arrow P by the first spiral blade 25a, and then is conveyed into the supply transfer chamber 20c through the upstream communication portion 20d, as in the case of development. Will be done. Further, the developer is conveyed in the supply transport chamber 20c in the direction of arrow Q by the second spiral blade 26a, and is conveyed to the deceleration transfer section 51. When the restricting portion 52 rotates with the rotation of the rotating shaft 26b, the regulating portion 52 applies a conveying force to the developer in a direction opposite to the developer conveying direction by the second spiral blade 26a. The developer whose transport speed has been decelerated in the deceleration transport section 51 is blocked near the deceleration transport section 51 located on the upstream side of the regulation section 52 and becomes bulky, and the surplus developer (replenishment from the developer supply port 20f). (Almost the same amount as the developed developer) is discharged to the outside of the developing container 20 via the first developing agent discharging unit 20g, overcoming the regulating unit 52.

FIG. 4 is a perspective view of the toner receiving support member 35 used in the developing apparatus 3a of the first embodiment as viewed from the inside of the developing container 20 (left side of FIG. 2), and FIG. 5 is an exploded perspective of the toner receiving supporting member 35. It is a figure.

The toner receiving member 37 is made of sheet metal and has a bent shape in which a bent portion 37a is formed along the longitudinal direction. , It is partitioned into a toner drop surface 37c that is substantially perpendicular to the toner supply roller 30. Further, the toner receiving member 37 is supported by the resin support member main body 36 via two coil springs 40. Specifically, an engaging portion 37d in which one end of the coil spring 40 engages is bent and formed at two positions at both ends of the toner receiving member 37, and a spring pedestal 39 (see FIG. 8) is formed at the other end of the coil spring 40. Is installed. The spring pedestal 39 is held by the spring pedestal holding portion 36a of the support member main body 36. Further, a holder holding portion 37e for supporting the vibration generator 42 is bent and formed at a substantially central portion of the toner receiving member 37.

A vibration motor 43 (see FIG. 6) and a board (not shown) on which circuits and electronic components for controlling the drive of the vibration motor 43 are mounted are arranged in the vibration generator 42, and the vibration motor 43 is arranged. A lead wire 45 for supplying power to is connected to.

Sheet members 41a and 41b (see FIG. 7) are attached to the surface of the toner receiving member 37. The sheet members 41a and 41b are made of a material that is less likely to adhere to the toner than the toner receiving member 37 in order to suppress the adhesion of toner to the toner receiving member 37. Examples of the material of the sheet members 41a and 41b include fluororesin sheets and the like.

The sheet member 41a is attached so as to cover the surface (toner drop surface 37c) of the toner receiving member 37 including the boundary between the support member main body 36 on the ear cutting blade 33 side and the toner receiving member 37. Further, the sheet member 41b is attached so as to cover the entire boundary of the support member main body 36 on the seal member 44 side and the toner receiving member 37, the engaging portion 37d, and the toner receiving surface 37b including the holder holding portion 37e. There is. The sheet members 41a and 41b suppress the adhesion of toner to the toner receiving surface 37b and the toner dropping surface 37c, and at the same time, the toner is transferred from the boundary between the support member main body 36 and the toner receiving member 37 to the inside of the toner receiving support member 35. Prevents malfunction of the vibration motor 43 due to entry and entry of toner.

Further, a film-shaped seal member 44 is provided at the upper end of the support member main body 36. The sealing member 44 extends in the longitudinal direction (left-right direction in FIG. 4) of the support member main body 36 so that the tip portion thereof contacts the surface of the photoconductor drum 1a, and is in the developing container 20 (see FIG. 2). It has a function to shield the toner from leaking to the outside.

FIG. 6 is an exploded perspective view of the vibration generator 42 in FIG. The vibration generator 42 includes a vibration motor 43, a motor mounting plate 42a to which the vibration motor 43 is fixed, and a cover member 42b, and a vibration weight 50 is fixed to the output shaft 43a of the vibration motor 43. .. Further, in the vibration motor 43, the output shaft 43a is fixed so as to be along the longitudinal direction of the toner receiving member 37.

The vibration weight 50 has an asymmetrical shape (for example, a cam shape) with respect to the output shaft 43a of the vibration motor 43. When the output shaft 43a rotates at a speed equal to or higher than a predetermined speed, a non-uniform centrifugal force is applied to the vibration weight 50. The vibration motor 43 vibrates when this centrifugal force is transmitted to the output shaft 43a. The shape of the vibration weight 50 is not limited to the cam shape, and may be any shape such that the center of gravity shifts with respect to the output shaft 43a.

7 and 8 are side sectional views showing an internal configuration of the toner receiving support member 35 used in the developing apparatus 3a of the first embodiment. 7 shows a cross section of the toner receiving support member 35 in the vicinity of the vibration motor 43 (XX'arrow cross section of FIG. 5), and FIG. 8 shows a cross section of the toner receiving support member 35 including the coil spring 40 (YY' of FIG. 5). (Cross section seen by arrow) is shown.

The toner receiving member 37 is inclined so that the toner receiving surface 37b facing the developing roller 31 has an upward gradient from the toner supply roller 30 side toward the photoconductor drum 1a side, and the toner falling surface 37c facing the toner supply roller 30 Are arranged so that they are approximately vertical. Further, the angle and surface roughness (friction coefficient) of the toner receiving surface 37b are adjusted so that the toner deposited on the toner receiving surface 37b does not naturally fall due to gravity, vibration caused by driving the developing device 3a, or the like.

As shown in FIGS. 7 and 8, in the toner receiving member 37, only the edge 37f on the toner supply roller 30 side is in contact with the support member main body 36, and the edge 37g on the opposite side (photoreceptor drum 1a side) is It is a free end. The substantially central portion of the toner receiving surface 37b in the width direction (left-right direction in FIG. 7) is supported by the support member main body 36 via the vibration generator 42. As a result, the toner receiving member 37 is configured to be swingable with the edge 37f as a fulcrum. Further, the vibration motor 43 is arranged so that the output shaft 43a is substantially parallel to the longitudinal direction of the toner receiving member 37.

The developing devices 3a to 3d of the present embodiment have a toner recovery mode in which the toner receiving member 37 in the developing devices 3a to 3d is vibrated by the vibration generating device 42 at the time of non-image formation to shake off the toner accumulated on the toner receiving surface 37b. It is feasible. Specifically, by rotating the output shaft 43a of the vibration motor 43 at high speed (for example, about 10,000 rpm) at the time of non-image formation, the vibration weight 50 also rotates at high speed together with the output shaft 43a. At this time, since a non-uniform 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. Then, the toner receiving member 37 to which the vibration generator 40 is attached also vibrates. Specifically, the toner receiving surface 37b of the toner receiving member 37 vibrates so that the amplitude increases toward the edge 37e with the edge 37d as a fulcrum. Due to the vibration of the toner receiving member 37, the toner deposited on the edge 37g side of the toner receiving surface 37b is flipped up toward the edge 37f side (in the direction of the white arrow) and gradually moves to the edge 37f side.

As shown in FIG. 8, the toner T deposited on the toner receiving surface 37b slides downward (in the direction of the white arrow in FIG. 8) along the inclination of the toner receiving surface 37b due to the vibration of the toner receiving surface 37b, and is substantially vertical. It freely falls into the region R sandwiched between the toner drop surface 37c and the toner supply roller 30. A part of the toner that has fallen into the region R passes through the gap between the ear cutting blade 33 and the toner supply roller 30 as it is, and falls into the supply transport chamber 20c.

In the present embodiment, in order to return the toner that has fallen to the region R to the supply transport chamber 20c, the developing roller 31 and the toner supply roller 30 are moved in the direction opposite to that at the time of image formation (clockwise direction in FIG. 7) during non-image formation. Rotate (counterclockwise). By rotating the toner supply roller 30 in the reverse direction, the toner that has fallen into the region R and accumulated on the tip of the ear cutting blade 33 is scraped off by the magnetic brush of the toner supply roller 30 and is carried around to the surface of the toner supply roller 30. It passes through the gap between the toner supply roller 30 and the ear cutting blade 33, is peeled off from the toner supply roller 30 at the same electrode portion of the fixed magnet body, and then is forcibly returned to the supply transfer chamber 20c.

The timing for vibrating the toner receiving member 37 may be performed every time the printing operation is completed, or when the number of printed sheets reaches a predetermined number or when the temperature in the developing device 3a becomes a predetermined value or higher. It may be done at the timing. Further, the timing of vibrating the toner receiving member 37 and the timing of rotating the developing roller 31 and the toner supply roller 30 in the reverse direction (or forward rotation) may be the same or different. Further, by vibrating the toner receiving member 37 every time the predetermined number of printed sheets is reached, the vibration of the toner receiving member 37 is automatically executed according to the number of printed sheets. Therefore, it is not necessary for the user to manually set the vibration of the toner receiving member 37, and it is possible to avoid setting mistakes, forgetting to set, or executing unnecessary vibration.

By the way, the toner deposited on the toner receiving member 37 is scattered toner floating in the developing container 20, and is an unstable toner in terms of charge. Therefore, the developer containing the toner shaken off from the toner receiving member 37 forms a magnetic brush on the toner supply roller 30, and the toner moves from the toner supply roller 30 to the developing roller 31 and is used for development. There is a possibility of causing problems such as.

Therefore, in the present invention, when the toner deposited on the toner receiving member 37 is recovered in the developing container 20 by the execution of the toner recovery mode, the developer containing a large amount of recovered toner is forcibly applied to the outside of the developing apparatus 3a. The developer discharge mode for discharging to is to be executed. Hereinafter, the procedure for executing the toner recovery mode and the forced discharge mode in the developing apparatus 3a of the first embodiment will be described in detail. In the developing devices 3b to 3d, the toner recovery mode and the forced discharge mode are executed in exactly the same procedure.

First, as described above, the toner recovery mode is executed in which the toner receiving member 37 is vibrated at a predetermined timing to shake off the toner accumulated on the toner receiving surface 37b. The toner that has slipped off the toner receiving member 37 is returned to the supply and transport chamber 20c.

Next, the forced discharge mode is executed following the toner recovery mode. FIG. 9 is a plan sectional view showing a stirring unit when the developer discharging mode is executed in the developing apparatus 3a of the first embodiment. In the developing apparatus 3a of the present embodiment, the driving of the stirring transfer screw 25 is stopped, and only the supply transfer screw 26 is driven to execute the forced discharge mode. In the supply transfer chamber 20c, the transfer force in the direction of arrow Q is generated by driving the supply transfer screw 26, but in the stirring transfer chamber 20b, the transfer force is not generated because the stirring transfer screw 25 is stopped.

As a result, the circulation of the developer from the supply transport chamber 20c to the stirring transport chamber 20b is retained, and the retention G of the developer is generated in the vicinity of the downstream communication portion 20e. As a result, the bulk of the developer locally increases in the vicinity of the restricting portion 52, so that a part of the developer gets over the restricting portion 52 and is discharged from the first developer discharging portion 20 g to the outside of the developing container 20. Therefore, the developer can be discharged from the first developer discharge unit 20 g without waiting for the bulk of the developer to increase due to the replenishment of the new developer.

By performing this forced discharge mode after the toner recovery mode, the developer can be discharged according to the timing when the recovered toner is returned to the supply and transport chamber 20c, and the recovered toner having an unstable charge amount can be efficiently discharged. Can be discharged. Therefore, it is possible to effectively suppress fog images and toner scattering due to poor charging of the toner in the developer.

Further, although the driving of the stirring transfer screw 25 is stopped in the above embodiment, the same effect can be obtained by causing the developer to stay by slowing down the rotation speed of the stirring transfer screw 25 more than usual.

The execution timing of the forced discharge mode is not particularly limited as long as it is during non-image formation, but the vibration generator 42 is operated by executing the toner recovery mode to collect the accumulated toner on the toner receiving member 37 in the developing container 20. The timing is preferable. Further, the execution timing of the forced discharge mode may be changed depending on the usage conditions, environmental conditions, and the like of the developing device 3a.

Further, since the recovered toner is recovered in the entire longitudinal direction of the toner supply roller 30, the execution time of the forced discharge mode is the transport time of the developer from the upstream end of the toner supply roller 30 to the first developer discharge portion 20 g. It is preferable to set the above. The transport time can be calculated using the circulation speed of the developer in the forced discharge mode and the distance from the upstream end portion (right end portion in FIG. 9) of the toner supply roller 30 to the first developer discharge portion 20 g.

FIG. 10 is a plan sectional view showing a configuration of a stirring unit of the developing apparatus 3a according to the second embodiment of the present invention. In the present embodiment, in addition to the first developer discharge unit 20 g (first developer discharge unit) that discharges excess developer when the developer is replenished, the second development that discharges the developer when the forced discharge mode is executed. The agent discharging unit 20j (second developing agent discharging unit) is provided. The configuration of other parts of the stirring portion of the developing apparatus 3a and the configuration in the vicinity of the toner receiving member 37 are the same as those of the first embodiment shown in FIGS. 2 to 8.

As shown in FIG. 10, during image formation, the rotation of the stirring and transporting screw 25 generates a transporting force in the direction of arrow P in the stirring and transporting chamber 20b, and the rotation of the feeding and transporting screw 26 causes the feeding and transporting chamber 20c in the direction of arrow Q. Transport force is generated. When a new developer is replenished from the developer replenishment port 20f with the consumption of the toner in the developing container 20, the carriers in the developing container 20 are not consumed by image formation, so only the amount of the replenished developer (carrier) is consumed. When the bulk of the developer in the developing apparatus 3a increases and the developer is transferred from the supply transfer screw 26 to the stirring transfer screw 25, the surplus developer gets over the restricting section 52 and disposes of the first developer discharge section 20 g. It is discharged through.

That is, the developing agent circulates in the developing container 20 in the counterclockwise direction of FIG. 10, and the developing agent in the supply transport chamber 20c is conveyed in the direction opposite to the second developing agent discharging unit 20j. It does not go to the developer discharging unit 20j. Further, since the discharge blade 53 in the second developer discharge unit 20j faces the same direction (in phase) as the second spiral blade 26a of the supply and transfer screw 26, the discharge blade 53 is supplied and transported from the second developer discharge unit 20j. A transport force is generated in the direction toward the chamber 20c. Therefore, the developer is not discharged from the second developer discharge unit 20j.

In the present embodiment, the forced discharge mode is executed by rotating the stirring transfer screw 25 and the supply transfer screw 26 in the reverse direction. FIG. 11 is a plan sectional view of the stirring unit when the forced discharge mode is executed in the developing apparatus 3a of the second embodiment. When the stirring transfer screw 25 and the supply transfer screw 26 are rotated in the reverse direction, the circulation direction of the developer in the developing container 20 is switched in the clockwise direction. As a result, the developer in the supply transport chamber 20c is transported in the direction toward the second developer discharge unit 20j. Further, the discharge blade 53 in the second developer discharge unit 20j generates a transfer force in the direction from the supply transfer chamber 20c to the second developer discharge unit 20j. As a result, when the developer is delivered from the supply transfer screw 26 to the stirring transfer screw 25, a part of the developer is discharged via the second developer discharge unit 20j.

By performing this forced discharge mode after the toner recovery mode, the developer can be discharged according to the timing when the recovered toner is returned to the supply and transport chamber 20c as in the first embodiment, and the charge amount is not high. Stable recovery toner can be discharged efficiently. Therefore, it is possible to effectively suppress fog images and toner scattering due to poor charging of the toner in the developer. The execution timing of the forced discharge mode can also be set in the same manner as in the first embodiment.

Further, since the recovered toner is recovered in the entire longitudinal direction of the toner supply roller 30, the execution time of the forced discharge mode is from the downstream end portion (left end portion in FIG. 11) of the toner supply roller 30 to the second developer discharge unit 20j. It is preferable to set it to be longer than the transport time of the developer up to. The transport time can be calculated using the circulation speed of the developer in the forced discharge mode and the distance from the downstream end of the toner supply roller 30 to the second developer discharge unit 20j.

FIG. 12 is a plan sectional view of the stirring unit when the forced discharge mode is executed in the developing apparatus 3a of the modified example of the second embodiment. In this modification, the second developer discharge portion 20j is provided on the side surface of the stirring and transporting chamber 20b facing the upstream communication portion 20d which is the transfer portion of the stirring and transporting screw 25 from the supply and transporting screw 26. The configuration of the other parts of the developing apparatus 3a is the same as that of the second embodiment shown in FIG.

Also in this modification, during image formation, the rotation of the stirring and transporting screw 25 generates a transporting force in the direction of arrow P in the stirring and transporting chamber 20b, and the rotation of the supply and transporting screw 26 causes the feeding and transporting chamber 20c to transport in the direction of arrow Q. Force is generated. That is, since the developer is delivered from the stirring and transporting chamber 20b to the supply and transporting chamber 20c in the upstream communication section 20d, the developer is not discharged from the second developer discharging section 20j.

On the other hand, when the forced discharge mode in which the stirring transfer screw 25 and the supply transfer screw 26 are rotated in the reverse direction is executed, the circulation direction of the developer in the developing container 20 is switched in the clockwise direction as shown in FIG. As a result, the developer is delivered from the supply transport chamber 20c to the stirring transport chamber 20b in the upstream communication section 20d, so that the developer in the supply transport chamber 20c is transported in the direction toward the second developer discharge section 20j. A part of the developer is discharged via the second developer discharge unit 20j. By performing this forced discharge mode after the toner recovery mode, the developer can be discharged according to the timing when the recovered toner is returned to the supply / transport chamber 22.

In the modified example shown in FIG. 12, the second developer discharge section 20j is provided on the side surface of the stirring transfer chamber 20b facing the upstream communication section 20d, but the position where the second developer discharge section 20j is provided is in this position. Not limited. For example, the second developer discharge unit 20j may be provided on the side surface of the supply / transport chamber 20c facing the downstream communication unit 20e. That is, the second developer discharge unit 20j is provided on the side surface of the developing container 20 which is perpendicular to the transport direction of the developing agent in the developing container 20 when the stirring transfer screw 25 and the supply transport screw are rotated in the forward direction and is on the upstream side. By providing the same, the developer can be discharged via the second developer discharge unit 20j when the stirring transfer screw 25 and the supply transfer screw 26 are rotated in the reverse direction.

Others The present invention is not limited to each of the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the shapes and configurations of the toner receiving support member 35 and the toner receiving member 37 shown in each of the above embodiments are merely examples and are not particularly limited to the above embodiments, and these are configurations of the developing devices 3a to 3d and the like. It can be set as appropriate according to the above. Hereinafter, the effects of the present invention will be described in more detail using examples.

In the developing devices 3a to 3d of the first embodiment shown in FIGS. 2 and 3, the stirring transfer screw 25 is stopped, only the supply transfer screw 26 is rotated, and the developer is discharged from the first developer discharging unit 20 g. I checked if it was. The test was performed on the cyan image forming unit Pa including the photoconductor drum 1a and the developing device 3a.

As the conditions of the testing machine, the process linear speed is 160 mm / sec, the diameter of the photoconductor drum 1a is 30 mm, the diameters of the toner supply roller 30 and the developing roller 31 are 16 mm each, and the linear speed ratio of the developing roller 31 to the photoconductor drum 1a is set. (S / D) was set to 1.8. Further, the ratio (T / C) of the toner of the developer and the carrier was set to 10%.

The first spiral blade 25a of the stirring transfer screw 25 has an outer diameter of 13 mm and a pitch of 30 mm, and the second spiral blade 26a of the supply transfer screw 26 has an outer diameter of 13 mm and a pitch of 30 mm. Further, the regulating portion 52 is composed of two reverse-wound (opposite-phase) spiral blades having an outer diameter of 12 mm and a pitch of 5 mm, and the distance between the regulating portion 52 and the second transport chamber 22d is 1.5 mm. The discharge blade 53 is a spiral blade having an outer diameter of 8 mm and a pitch of 5 mm, and the distance between the discharge blade 53 and the first developer discharge portion 22 g is 1 mm.

Then, in a state where the stirring transfer screw 25 and the supply transfer screw 26 are rotated at a rotation speed of 330 rpm to circulate and convey the developer, and in a state where only the stirring transfer screw 25 is stopped, the first developer discharge unit 20 g. We confirmed the discharge status of the developer from.

As a result of the test, it was not confirmed that the developer was discharged from the first developer discharge unit 20 g in the state where both the stirring transfer screw 25 and the supply transfer screw 26 were rotated. On the other hand, in the state where only the stirring transfer screw 25 is stopped, the developer stays on the downstream side of the supply transfer chamber 20c with respect to the developer transfer direction, and the developer from the first developer discharge unit 20 g. Emission was confirmed. From this result, it was confirmed that the developer containing the recovered toner can be discharged by executing the forced discharge mode in which only the stirring transfer screw 25 is stopped after the toner recovery mode is executed.

In the developing devices 3a to 3d of the second embodiment shown in FIGS. 10 and 11, whether the developing agent is discharged from the second developing agent discharging unit 20j by rotating the stirring transport screw 25 and the supply transport screw 26 in the reverse direction. I checked. The test was performed on the cyan image forming unit Pa including the photoconductor drum 1a and the developing device 3a.

The conditions of the testing machine, the first spiral blade 25a of the stirring transfer screw 25, the second spiral blade 26a of the supply transfer screw 26, and the regulation section 52 are the same as those of the first embodiment, and the configuration of the second developer discharge section 22j is the same. Was the same as that of the first developer discharging unit 22 g. Then, the stirring transfer screw 25 and the supply transfer screw 26 are rotated forward at a rotation speed of 330 rpm to circulate and convey the developer, and the stirring transfer screw 25 and the supply transfer screw 26 are rotated in the reverse direction at a rotation speed of 330 rpm. Then, the discharge status of the developer from the second developer discharge unit 20j was confirmed.

As a result of the test, it was not confirmed that the developer was discharged from the second developer discharge unit 20j in the state where the stirring transfer screw 25 and the supply transfer screw 26 were rotated in the forward direction at the time of image formation. On the other hand, in a state where the stirring transfer screw 25 and the supply transfer screw 26 are rotated in the reverse direction, a flow of the developer toward the second developer discharge section 20j is generated, and the developer from the second developer discharge section 20j is generated. Emission was confirmed. From this result, it was confirmed that the developer containing the recovered toner can be discharged by executing the forced discharge mode in which the stirring transfer screw 25 and the supply transfer screw 26 are rotated in the reverse direction after the toner recovery mode is executed.

INDUSTRIAL APPLICABILITY The present invention can be used in a developing device capable of executing a toner recovery mode in which toner accumulated around a regulation blade is recovered in a casing. By utilizing the present invention, it is possible to efficiently discharge the developer containing the toner recovered in the casing, and provide a developing apparatus capable of effectively suppressing a fog image and toner scattering due to poor charging of the toner in the developer. can do.

Pa to Pd Image forming part 1a to 1d Photoreceptor drum (image carrier)
2a to 2d Charging device 3a to 3d Developing device 5 Exposure device 20 Developing container 20a Partition 20b Stirring transfer room (first transfer room)
20c Supply transport room (second transport room)
20d Upstream communication part 20e Downstream communication part 20f Developer supply port 20g 1st developer discharge part 20j 2nd developer discharge part 25 Stirring transfer screw (1st stirring transfer member)
25a 1st transfer blade 25b Rotating shaft 26 Supply transfer screw (2nd stirring transfer member)
26a 2nd transport blade 26b Rotating shaft 30 Toner supply roller 31 Developing roller 33 Head cutting blade (regulated blade)
35 Toner receiving support member 37 Toner receiving member 40 Vibration generator 55 Transport amount adjustment unit 100 Color printer (image forming device)

Claims (7)

The first transport chamber, the second transport chamber arranged in parallel with the first transport chamber with the partition portion interposed therebetween, and the first transport chamber and the second transport chamber on both ends in the longitudinal direction of the partition portion. A developing container that has a communication unit and contains a two-component developer containing a carrier and a toner.
A first stirring and transporting member that stirs and transports the developer in the first transporting chamber in the direction of the rotation axis.
A second stirring and transporting member that stirs and transports the developer in the second transporting chamber in the direction opposite to that of the first stirring and transporting member.
A developer supply port for replenishing the developer in the developing container,
A developer discharging unit that discharges excess developing agent from the developing container,
A developing roller that is rotatably supported in the developing container and supplies toner to the image carrier in a region facing the image carrier on which an electrostatic latent image is formed.
A toner supply roller that is rotatably supported by the developing container, supports the developer in the second transport chamber on the surface, and supplies toner to the developing roller in a region facing the developing roller.
A regulating blade arranged to face the toner supply roller at a predetermined interval,
A toner receiving member that is arranged opposite to the developing roller or the toner supply roller between the regulating blade and the image carrier in the developing container and receives toner falling from the developing roller.
A vibration generator that vibrates the toner receiving member and
Equipped with
In a developing device capable of executing a toner recovery mode in which the toner receiving member is vibrated by the vibration generating device at the time of non-image formation to shake off the toner accumulated on the toner receiving member and collected in the second transport chamber.
After executing the toner recovery mode, it is possible to execute a forced discharge mode in which the developer containing the recovered toner collected in the second transport chamber is forcibly discharged from the developer discharging unit to the outside of the developing container.
The developer discharge unit is a first developer discharge unit provided at the downstream end of the second transport chamber with respect to the transport direction of the developer in the second transport chamber.
After the execution of the toner recovery mode, the rotation speed of the first stirring and transporting member is made slower than the rotation speed of the second stirring and transporting member, so that the developer containing the recovered toner is discharged from the first developer discharging unit. A developing device characterized by executing the forced discharge mode . The execution time of the forced discharge mode is equal to or longer than the transport time of the developer from the upstream end of the toner supply roller to the first developer discharge portion with respect to the transport direction of the developer when the forced discharge mode is executed. The developing apparatus according to claim 1, wherein the developing apparatus is provided. The first transport chamber, the second transport chamber arranged in parallel with the first transport chamber with the partition portion interposed therebetween, and the first transport chamber and the second transport chamber on both ends in the longitudinal direction of the partition portion. A developing container that has a communication unit and contains a two-component developer containing a carrier and a toner.
A first stirring and transporting member that stirs and transports the developer in the first transporting chamber in the direction of the rotation axis.
A second stirring and transporting member that stirs and transports the developer in the second transporting chamber in the direction opposite to that of the first stirring and transporting member.
A developer supply port for replenishing the developer in the developing container,
A developer discharging unit that discharges excess developing agent from the developing container,
A developing roller that is rotatably supported in the developing container and supplies toner to the image carrier in a region facing the image carrier on which an electrostatic latent image is formed.
A toner supply roller that is rotatably supported by the developing container, supports the developer in the second transport chamber on the surface, and supplies toner to the developing roller in a region facing the developing roller.
A regulating blade arranged to face the toner supply roller at a predetermined interval,
A toner receiving member that is arranged opposite to the developing roller or the toner supply roller between the regulating blade and the image carrier in the developing container and receives toner falling from the developing roller.
A vibration generator that vibrates the toner receiving member and
Equipped with
In a developing device capable of executing a toner recovery mode in which the toner receiving member is vibrated by the vibration generating device at the time of non-image formation to shake off the toner accumulated on the toner receiving member and collected in the second transport chamber.
After executing the toner recovery mode, it is possible to execute a forced discharge mode in which the developer containing the recovered toner collected in the second transport chamber is forcibly discharged from the developer discharging unit to the outside of the developing container.
The developer discharging unit is the second transfer with respect to the transfer direction of the developer in the second transfer chamber when the first stirring transfer member and the second stirring transfer member are rotated in the same direction as at the time of image formation. In the developing container when the first developer discharging portion provided at the downstream end of the chamber, the first stirring and transporting member, and the second stirring and transporting member are rotated in the opposite direction to the rotation direction at the time of image formation. It is composed of a second developer discharge portion provided on the side surface of the developing container, which is perpendicular to the transport direction of the developer and is on the downstream side.
After the toner recovery mode is executed, the developer containing the recovered toner is discharged from the second developer discharge unit by rotating the first stirring and transporting member and the second stirring and transporting member in the reverse direction with respect to the rotation direction at the time of image formation. A developing device characterized by executing the forced discharge mode of discharging . The second developer discharging unit faces the communication unit that transfers the developer from the first transport chamber to the second transport chamber when the first stirring and transporting member and the second stirring and transporting member are rotated in the forward direction. The developing apparatus according to claim 3 , wherein the developing apparatus is provided on the side surface of the first transport chamber . The execution time of the forced discharge mode is equal to or longer than the transport time of the developer from the upstream end of the toner supply roller to the second developer discharge portion with respect to the transport direction of the developer when the forced discharge mode is executed. The developing apparatus according to claim 3 or 4, wherein the developing apparatus is provided. The developing apparatus according to any one of claims 1 to 5 , wherein when the toner recovery mode is executed, the toner supply roller is rotated in a direction opposite to that at the time of image formation . An image forming apparatus comprising the developing apparatus according to any one of claims 1 to 6 .

Images