JP5196047B2 - Developing device and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device that develops an electrostatic latent image on a latent image carrier, a copier equipped with the developing device, a printer, a facsimile machine, a plotter, and a composite machine equipped with at least one of these. Relates to the device.

The developing device is a device that develops and visualizes the electrostatic latent image formed on the latent image carrier using a two-component developer composed of toner and carrier.
The developer whose toner has been consumed after completion of the development process in the development area is collected, mixed with the replenished toner, stirred, and again developed. In order to obtain a stable toner image, the developer used in the developing device having such a configuration needs to maintain a constant toner concentration and charge amount.
The toner density is adjusted by the amount of toner consumed during development and the amount of replenished toner, and the charge amount is given by frictional charging during mixing of the carrier and toner. In the developing device, the two-component developer composed of the toner and the carrier is sufficiently stirred to make the toner density distribution uniform, and the toner is charged to stabilize the toner image.

In a general developing device, toner is dispersed and charged by using the stirring effect of the rotation of two screws during a short time until the replenished toner is pumped up to the developing sleeve. Particularly when the toner balance is large, the replenished toner is not sufficiently dispersed but is drawn up to the developing sleeve, resulting in quality problems such as background contamination and toner scattering.
In order to solve this problem, a separate agitation unit is provided at a location distant from the development unit, the development unit and the agitation unit are connected by a developer circulation means, and the agitation unit performs agitation according to the state of the developer, and There has been proposed a developing device that supplies a developer with appropriately adjusted density and charge amount to a developing unit (see, for example, Patent Documents 1, 2, and 3).
The developer adjusted (optimized) by the agitating unit is conveyed (transferred) to the developing unit by air pressure while the discharge amount is regulated by a rotary feeder.

These developing devices that circulate the developer using air have the following problems.
When the developer is continuously conveyed through the pipe using air, the main components are a developer storage part (stirring part) 51, a developer supply part (lower end part of the stirring part 51), a transport pipe 56, etc. An air supply source 54 (see FIG. 2).
Since the developer is transported using air pressure (positive pressure) and flow velocity, a differential pressure is generated between the air transport source and the transport destination (atmospheric pressure). In the developing device of the present invention, since the sent developer is collected from the developing unit 50 to the developer storing unit 51 and is transported (circulated) again, the developer storing unit 51 is also at atmospheric pressure.
Therefore, in order to transport the developer to the developing unit 50, it is necessary to seal the developer supply unit so that the air from the air supply source does not leak into the storage unit.
If air leaks, the pressure for transporting the developer decreases, and the transport amount cannot be secured sufficiently. Further, when the air flows back to the storage unit (pressure is applied to the storage unit), the developer entering the supply unit from the storage unit is hindered by the back-flowing air, and the discharge amount decreases and varies.

A rotary feeder is commonly used as a supply device in the supply unit. The rotary feeder is composed of a rotor having a plurality of rotating blades and a stator that covers the rotor, and is a method with excellent quantitativeness and controllability. However, when the sealing property is insufficient, the above-described air backflow occurs.
As a method for ensuring the sealing performance, there is a method in which the rotor blades are made of an elastic body and the stator is bitten. However, the deterioration with time (rotation of the rotor and the stator) becomes remarkable, which is not practical.
In particular, since the developer carrier is iron or ferrite, the hardness is high, and it is difficult to obtain durability by this method.

  The present invention has been made in view of the above-described points. The present invention can be efficiently stirred in a short time with less stress applied to the developer, and can be charged with toner. An object of the present invention is to provide a developing device capable of continuously and stably supplying an amount of developer in an amount necessary for development, and an image forming apparatus having the developing device.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a developing unit that develops a latent image on the latent image carrier, and a developer storage unit that is provided outside the developing unit and stores the developer. , A supply device for discharging the developer in the developer storage unit, a developer transfer path for transferring the developer discharged from the supply device to the development unit, and supplying air into the developer transfer path An air supply source that transfers the developer discharged from the supply device to the developing unit by transferring the developer transfer path using the air supplied from the air supply source. An air supply path for supplying air from the air supply source is connected to a discharge path on the discharge side of the supply apparatus, and the developer is disposed between the discharge side of the supply apparatus and the developer transfer path. The angle formed with the direction of air flow in the transfer path Chi, wherein the upstream side of the flow of air is provided plate-like member fixed to be inclined such that acute angle.

According to the second aspect of the present invention, a developing unit that develops the latent image on the latent image carrier, a developer storing unit that is provided outside the developing unit and stores the developer, and development of the developer storing unit A supply device for discharging the developer, a developer transfer path for transferring the developer discharged from the supply device to the developing unit, and an air supply source for supplying air into the developer transfer path. In the developing device that transports the developer discharged from the supply device to the developing unit by using the air supplied from the air supply source and transports it to the developing unit, the discharge side of the supply device Between the first position and the developer transfer path, and a plate-shaped member that can be displaced between a first position and a second position. The plate-shaped member is located closer to the developer transfer path than the first position when in the second position. Inflow of air to the supply device side is limited .
In the invention of claim 3, wherein, in the developing apparatus according to claim 1, wherein said plate-like member, characterized in that at intervals the feed direction of the air are provided in plural.
According to a fourth aspect of the present invention, in the developing device according to the second aspect , the plate-like member has a second position that restricts the inflow of air and a first position that allows the developer to be discharged by the supply device. The plate-like member is displaceable, and when air is supplied, the plate-like member is set at a second position that restricts the inflow of air.

According to a fifth aspect of the present invention, in the developing device according to the fourth aspect, the plate-like member is provided so as to maintain a first position that allows the discharge of the developer, and when air is supplied, air flows in by air pressure. Displacement to a second position that restricts
According to a sixth aspect of the present invention, in the developing device according to the fourth aspect, the plate-like member is provided so as to maintain a first position allowing discharge of the developer by its own weight, and when air is supplied, the air is supplied by air pressure. It is characterized by being displaced to a second position that restricts the inflow of water .
According to a seventh aspect of the present invention, in the developing device according to the fourth aspect of the invention, there is provided a driving source that selectively sets the plate-like member to a second position that restricts the inflow of air and a first position that permits the discharge. It is characterized by that.

According to an eighth aspect of the present invention, in the developing device according to any one of the fourth to seventh aspects, when the plate-like member is in the second position that restricts the inflow of air, the displaced end portion is the periphery. It is characterized by not touching.
According to a ninth aspect of the present invention, in the developing device according to any one of the fourth to eighth aspects, a valve is provided in the air supply path, and air is intermittently supplied by switching the valve.
According to a tenth aspect of the present invention, an image forming apparatus includes the developing device according to any one of the first to ninth aspects.

  According to the present invention, it is possible to reduce the amount of air used for developer conveyance flowing into the agitation unit, so that the developer can be reliably conveyed to the development unit, and the discharge amount of the developer from the agitation unit is stabilized. be able to.

1 is a schematic cross-sectional view of an image forming apparatus according to a first embodiment of the present invention. It is a perspective view of a developing device. It is sectional drawing of a stirring part etc., (a) is a horizontal sectional view in CC line, (b) is a longitudinal cross-sectional view of a stirring part. It is sectional drawing which shows the flow of the developer in a stirring part. It is sectional drawing of the circulation path of the lower part with a rotary feeder. It is sectional drawing of a image development part. FIG. 7A is a cross-sectional view of a circulation path below the rotary feeder in the second embodiment, and FIG. 5A is a diagram illustrating a state in which an air inflow restricting member is set at a position that allows developer discharge; FIG. 6 is a diagram showing a state where the air inflow restricting member is set at a position where air inflow is restricted. FIG. 7A is a cross-sectional view of a circulation path below a rotary feeder in a third embodiment, and FIG. 5A is a diagram illustrating a state where an air inflow restricting member is set at a position where developer discharge is allowed; FIG. 6 is a diagram showing a state where the air inflow restricting member is set at a position where air inflow is restricted. It is sectional drawing which shows the connection structure of the rotary feeder and air supply source in 4th Embodiment. It is a schematic plan view which shows the drive structure of an air inflow control member. It is a figure which shows the state by which the air inflow control member is set to the position which controls the inflow of air. It is a graph which shows the relationship between the flow velocity of air, and the average flow volume of a developer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A first embodiment will be described with reference to FIGS. First, an outline of a configuration of an image forming apparatus including a developing device according to the present embodiment will be described with reference to FIG.
Opposite to the lower surface of the intermediate transfer belt 8 as an unfixed image carrier in the intermediate transfer unit 10, image forming units 6Y, 6M, 6C, and 6Bk corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel. ing. These image forming units 6Y, 6M, 6C, and 6Bk have the same structure except that the color of the toner used in the image forming process is different.
Each image forming unit 6 includes a photosensitive drum 1 as a latent image carrier, a charging unit (not shown) disposed around the photosensitive drum 1, a developing device 5, a cleaning unit (not shown), and the like.

An image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photosensitive drum 1, and a desired toner image is formed on the photosensitive drum 1.
The photosensitive drum 1 is rotationally driven in the clockwise direction in the figure by a driving unit (not shown), and the surface is uniformly charged at the position of the charging means (charging process).
Thereafter, the surface of the photosensitive drum 1 reaches an irradiation position of a laser beam emitted from an exposure unit (not shown), and an electrostatic latent image is formed by exposure scanning at this position (exposure process).
Thereafter, the surface of the photosensitive drum 1 reaches a position facing the developing device 5, and the electrostatic latent image is developed at this position to form a desired toner image (developing process).
Thereafter, the surface of the photosensitive drum 1 reaches a position facing the intermediate transfer belt 8 and the primary transfer bias roller 9, and the toner image on the photosensitive drum 1 is transferred onto the intermediate transfer belt 8 at this position. (Primary transfer process).
Thereafter, the surface of the photoreceptor 1 reaches a position facing the cleaning unit, and untransferred toner remaining on the photoreceptor drum 1 is collected at this position (cleaning step). After cleaning, the surface of the photosensitive drum 1 is initialized with the potential of a neutralizing roller (not shown). Thus, a series of image forming processes performed on the photosensitive drum 1 is completed.

  As shown in FIG. 1, the image forming process described above is performed by each of the four image forming units 6Y, 6M, 6C, and 6Bk. That is, laser light based on image information from an exposure unit (optical writing device) (not shown) disposed below the image forming unit is applied to the photosensitive drums of the image forming units 6Y, 6M, 6C, and 6Bk. Irradiated toward. Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 8 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8.

The four primary transfer bias rollers 9Y, 9M, 9C, and 9Bk respectively sandwich the intermediate transfer belt 8 with the photosensitive drums 1Y, 1M, 1C, and 1Bk to form a primary transfer nip. The primary transfer bias rollers 9Y, 9M, 9C, and 9Bk are applied with a transfer bias having a polarity opposite to the polarity of the toner.
The intermediate transfer belt 8 runs in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 9Y, 9M, 9C, and 9Bk. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1Bk are primarily transferred while being superimposed on the intermediate transfer belt 8.

Thereafter, the intermediate transfer belt 8 onto which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19 as a secondary transfer unit. The color toner image formed on the intermediate transfer belt 8 is transferred onto a transfer sheet P as a recording medium conveyed to the secondary transfer nip position.
Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.
A plurality of transfer sheets P are stored in a paper feeding unit 26 disposed in the lower part of the apparatus main body 100, and are separated and fed one by one by a paper feeding roller 27. The fed transfer paper P is temporarily stopped by the registration roller pair 28, and after the oblique deviation is corrected, it is conveyed toward the secondary transfer nip by the registration roller pair 28 at a predetermined timing. As described above, a desired color image is transferred onto the transfer paper P at the secondary transfer nip.

The transfer paper P onto which the color image has been transferred at the position of the secondary transfer nip is conveyed to the fixing unit 20, where the color image transferred to the surface is fixed by heat and pressure generated by the fixing roller and the pressure roller. The
After the fixing, the transfer paper P is discharged as an output image to the paper discharge unit 30 formed on the upper surface of the apparatus main body by the paper discharge roller pair 29 and stacked. Thus, a series of image forming processes in the image forming apparatus is completed.
In FIG. 1, the code | symbol 32 has shown the reading part.

Next, the configuration of the developing device 5 as the developer agitation / circulation system will be described in detail.
As shown in FIG. 2, the developing device 5 includes a developing unit 50 that develops the electrostatic latent image on the photosensitive drum 1, and a developer (hereinafter simply referred to as “agent”) at a position away from the developing unit 50. An agitation unit 51 as a developer storage unit that performs agitation in accordance with the state of the toner, a toner cartridge 52 for supplying toner to the agitation unit 51, and a rotary feeder 53 as a supply device provided below the agitation unit 51. And a developer circulation drive source for conveying the developer by air pressure, and an air pump 54 as an air supply source . In FIG. 1, only the developing unit 50 is shown.
The developing section 50 and the stirring section 51 are connected by a circulation path 55, and the rotary feeder 53 and the developing section 50 are connected by a circulation path 56 as a developer transfer path . The toner cartridge 52 and the stirring unit 51 are connected by a toner supply path 57, and the air pump 54 and the rotary feeder 53 are connected by a pipe line 58.
In FIG. 2, reference numeral 59 denotes a motor as a toner replenishment drive source, 60 denotes a motor as an agitation drive source, and 61 denotes a motor as a drive source of the rotary feeder 53.

As shown in FIG. 6, the developing unit 50 includes a casing 62 constituting a developing device, conveyance screws 63 and 64 that are rotatably supported in the casing 62 and have spiral fins, and a developing roller 65. ing. The casing 62 contains a two-component developer in which toner and carrier are mixed. The developer is circulated and conveyed in the casing 62 by the conveying screws 63 and 64.
The developer is transported from the front side to the back side in the drawing by the transport screw 63, and a part of the developer is sucked and attracted by the magnetic force by the developing roller 65, and is uniformed to a uniform thickness by the doctor blade 66. By contacting the body drum 1, the electrostatic latent image on the photoreceptor drum 1 is developed with toner to form a toner image.

The developed developer is transported from the discharge port 67 (see FIG. 2) formed at the end of the transport screw 64 to the stirring unit 51 through the circulation path 55. A toner density detecting means (not shown) is installed at the most downstream side of the conveying screw 64, and toner is replenished from the toner cartridge 52 based on the signal.
Toner supply is performed by rotating a screw (not shown) in the toner supply path 57 by the motor 59. Toner replenishment is performed in the circulation path immediately before the entrance of the agitation unit 51.
In the stirring unit 51, the developer after development and the replenished toner are mixed to form a developer having an appropriate toner concentration and charge amount. As shown in FIG. 3, the developer passes through the discharge port 70 formed in the lower part of the stirring unit 51 and enters the rotary feeder 53.
The developer is quantitatively discharged downward by the rotation of the rotor 75 in the rotary feeder 53, passes through the circulation path 56, and is supplied again to the developing unit 50 through the receiving port 68.

FIG. 3 is a cross-sectional view of the stirring unit 51. A developer replenishing port 69 is provided on the upper surface of the stirring unit 51, and a discharge port 70 is provided on the lower surface. The stirrer body 51 a has an inverted conical shape whose diameter decreases toward the discharge port 70. ing.
A screw 71 that conveys the agent from the bottom to the top is provided in the center of the stirring unit main body 51a, and two rotatable stirring members 72 are provided on the outer side thereof. The developer is rotated by the rotating operation of these stirring members. Is stirred and mixed.
The outer stirring member 72 and the screw 71 are rotated by the motor 60. The screw 71 is directly connected to the motor 60, and the outer stirring member 72 rotates through the reduction gear trains 73a to 73d. As shown in FIG. 3A, the stirring member 72 is fixed obliquely with respect to a support portion 74 that is directly connected to the reduction gear train.
The conveyance from the replenishment port 69 to the discharge port 70 in the stirring unit 51 uses gravity. Since the developer is always present as a buffer in the stirring unit 51, the unmixed developer is not discharged as it is.
The rotary feeder 53 includes a rotor 75 having a plurality of blades 75 a that are rotated by a motor 61 and extend radially, and a stator 76 that covers the rotor 75. The rotary feeder 53 is connected to the circulation path 56 and the pipe line 58 by a joint pipe line 77.

FIG. 4 is a schematic diagram illustrating the flow of the developer during stirring in the stirring unit 51.
The agent lifted upward in the direction of the arrow A by the rotation of the screw 71 moves in the direction of the arrow B along with the rotation of the stirring member 72 that rotates on the outside, and is collected around the screw 71 again.
As described above, the developer is constantly convected in the stirring unit 51. By this convection, the entire container (inside the stirring unit main body 51a) is uniformly mixed. Since the toner is charged by the friction between the toner and the carrier, it is important to increase the contact probability between the toner and the carrier in order to quickly obtain the charge amount.
As a result of the study by the present inventors, it has been found that the contact probability is increased by convection of the developer in the stirring portion 51, and the damage to the developer is small.

Next, the rotary feeder unit will be described in detail.
As shown in FIG. 5, the rotor 75 and the stator 76 of the rotary feeder 53 are provided with a clearance between the tip of the blade 75 a of the rotor 75 and the inner surface of the stator 76.
As described above, if there is a gap between the rotor 75 and the stator 76, a part of the air generated from the air pump 54 passes through this gap and flows into the agitation unit 51 to send the developer to the development unit 50. Air is reduced (pressure is reduced).
Of course, the larger the gap, the easier the air will pass. However, when the developer is being transported, the developer enters the gap to generate a sealing effect, and the air leakage is reduced. However, if the gap is too large, the sealing effect is lost and air leakage cannot be prevented.
That is, in order to efficiently convey the developer discharged from the rotary feeder 53, it is preferable not to allow the air of the air pump 54 to flow into the stirring unit 51 as much as possible.

Therefore, in the present embodiment, a plate-like air inflow restriction that restricts the inflow of air to the rotary feeder 53 side between the discharge side of the rotary feeder 53 and the developer transfer path (here, in the joint pipe line 77). A member 80 is arranged. Three air inflow regulating members 80 are fixedly arranged at intervals in the air supply direction.
When the air sent from the air pump 54 reaches the inside of the joint pipe 77 as the mixing portion, the air transferred to the developing portion 50 together with the developer in the circulation passage 56 and the reverse flow toward the upper rotary feeder 53 side. Although there is air, since the air inflow restricting member 80 restricts the flow of air, the air flowing backward to the rotary feeder 53 side is reduced.
The air inflow restricting member 80 is installed so that the upper end portion thereof is inclined toward the air pump 54 side and the angle θ formed with the horizontal line is an acute angle, and therefore restricts the air flow toward the rotary feeder 53 side. High effect. The developer discharged from the rotary feeder 53 falls between the air inflow restricting member 80 and the joint pipe 77 inner surface and between the air inflow restricting members 80.
Although one air inflow restricting member 80 may be provided, the air inflow restricting function is higher when a plurality of air inflow restricting members 80 are provided.

A second embodiment will be described based on FIG. Note that the same parts as those in the above embodiment are denoted by the same reference numerals, and unless otherwise specified, description of the configuration and functions already described is omitted, and only the main part will be described (the same applies to other embodiments below).
In the said embodiment, although it was set as the structure which fixes and arranges the air inflow control member 80 in a mixing part, in this case, there exists the following concerns.
Although the developer can pass between the air inflow restricting members 80, the air inflow restricting member 80 prevents the flow of the developer discharged from the rotary feeder 53, so that the discharge amount from the rotary feeder 53 decreases. There is a fear.
That is, there is a concern that all the developer in the rotary feeder 53 does not fall, but accumulates in the merging portion and returns upward again.
Further, when the developer path becomes narrow, the developer may be cross-linked to cause clogging.
The present embodiment aims to eliminate such concerns.

As shown in FIG. 7A, a single plate-like air inflow restricting member 81 that is pivotally supported so as to be rotatable (displaceable) at the center is provided in the joint pipe 77.
The air inflow restricting member 81 is maintained at a first position that allows the developer to be discharged as shown in the drawing by an elastic member (for example, a spring) (not shown) when air is not supplied.
When air is supplied by the air pump 54, as shown in FIG. 7B, the air inflow restricting member 81 is rotationally displaced by the air pressure and automatically reaches the second position for restricting the inflow of air to the rotary feeder 53 side. Set to Therefore, while air is being supplied, the air flow path toward the rotary feeder 53 is blocked by the air inflow restricting member 81, and almost no air leakage occurs.
By controlling the air pump 54 to operate intermittently, the developer can be efficiently conveyed to the developing unit 50.
In the present embodiment, the air inflow restricting member 81 is configured to be maintained at the “position where developer discharge is permitted” by an elastic force. However, the air inflow restricting member 81 may be maintained by a magnetic force, and the lower half or the lower end is made heavy. It may be kept under its own weight.

In the present embodiment, the air inflow restricting member 81 is in contact with the inner surface of the joint pipe line 77 at the “position where air inflow is restricted”. However, in this case, the developer may be sandwiched to deteriorate the developer. .
In order to eliminate such a concern, a member (for example, a protrusion or a rod-like member) that comes into contact immediately before the outer end portions of the air inflow restricting member 81 come into contact with the inner surface of the joint conduit 77 is provided. It is only necessary to create a gap between them (same in other embodiments below).
Even if there is a gap, the developer is accumulated in the upper part (rotary feeder side), so that the air hardly enters the rotary feeder 53 side by this gap.

FIG. 8 shows a third embodiment.
As shown in FIG. 8A, the air inflow restricting member 82 in the present embodiment has a single plate shape, and its upper end is pivotally supported on the inner surface of the stator 76. The lower end portion of the air inflow restricting member 82 hangs down so as to block the air passage of the joint pipe line 77, and maintains the first position allowing discharge of the developer by its own weight.
When the air supply is made by an air pump 54, as shown in FIG. 8 (b), the second air inflow control member 82 is rotationally displaced pneumatically the upper end as a fulcrum, to regulate the inflow of air into the rotary feeder 53 side The position is automatically set.
Therefore, while the air is supplied, the air flow path toward the rotary feeder 53 is blocked by the air inflow restricting member 82, and almost no air leakage occurs. When the air supply is stopped, it returns to its original position (position where developer discharge is allowed) by its own weight.
Also in the present embodiment, the developer can be efficiently conveyed to the developing unit 50 by controlling the air pump 54 to operate intermittently.

A fourth embodiment will be described with reference to FIGS.
As shown in FIG. 9, the air inflow restricting member 83 in the present embodiment has a single plate shape, and an upper end portion thereof is fixed to a rotating shaft 84 that is rotatably supported on the inner surface of the stator 76.
As shown in FIG. 10, the rotation shaft 84 is driven by a motor 85. FIG. 9 shows a state in which the air inflow restricting member 83 is set to a position that allows the developer to be discharged.
When air is supplied, the air inflow restricting member 83 is automatically set to a position where air inflow is restricted by control of the motor 85 by a control means (not shown) as shown in FIG.
As shown in FIG. 9, a valve 86 is arranged between the air pump 54 and the mixing section, and the valve 86 can switch the internal air path between the mixing section and the N direction in the figure by an electric signal. Yes.

The air inflow restricting member 83 and the valve 86 are controlled to repeat ON / OFF in synchronization. When the air inflow restricting member 83 is in the state shown in FIG. 9, the air is discharged in the N direction, and the state shown in FIG. When the valve 86 is switched, it flows into the mixing section. That is, air is supplied intermittently.
By using the valve 86, the air supply can be easily turned on / off by an electric signal or the like. In particular, when an air pump using a motor is used as an air supply source, the motor cannot be immediately rotated / stopped due to inertia in the ON / OFF control of the motor, so the response of air supply is poor. Good responsiveness can be obtained.
When air is used in this way, when air flows into the mixing unit and the developer is transferred, the air inflow restricting member 83 blocks the rotary feeder 53 and the mixing unit, so that the air flows into the rotary feeder 53 side. Can be greatly reduced.
As described above, the air inflow restricting member 83 does not have to be completely in contact with the inner surface of the mixing portion (joint pipe line 77) and the inner surface of the stator 76. There may be a clearance of about 0.1 mm or less. This is because the developer discharged from the rotary feeder 53 is buried in this clearance portion, so that almost no air flows in the clearance of this level.

There is a concern that the flow rate of the developer may be reduced by intermittently supplying air as compared to the case where the air is continuously supplied. However, even if air is continuously supplied as described above, the flow to the rotary feeder 53 side may be increased. When flowing in, the air used for conveyance decreases, and conversely, the flow rate decreases.
Moreover, since the developer falling from the stirring unit 51 is hindered by this air, the amount of developer entering the rotary feeder 53 is reduced, and the flow rate is further reduced.
In the present embodiment, since such a flow rate decrease does not occur, the flow rate is larger than the continuous supply under the same conditions (the size of the rotary feeder, the rotation speed, and the amount of air).
FIG. 12 shows the results of a developer transfer experiment with continuous supply and intermittent supply. The intermittent supply is a result of the supply amount when the air and the air inflow restricting member 83 are turned ON / OFF at intervals of 0.5 sec.
The rotary feeder 53 can be intermittent according to the intermittent air operation, but is rotating continuously in this experiment.
As described above, by reducing the inflow of air to the rotary feeder 53 side, the air can be utilized to the maximum extent for transporting the developer, so that the developer can be stably transferred with high efficiency and reliability. Can do.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum as a latent image carrier 5 Developing apparatus 50 Developing part 51 Stirring part 53 Rotary feeder 75 Rotor 76 Stator 80, 81, 82, 83 Air inflow control member 85 Motor as drive source

Japanese Patent No. 3733496 Japanese Patent No. 3349286 JP-A-11-143196

Claims (10)

A developing unit that develops the latent image on the latent image carrier, a developer storing unit that is provided outside the developing unit and stores the developer, and a supply device that discharges the developer in the developer storing unit;
A developer transfer path for transferring the developer discharged from the supply device to the developing unit;
An air supply source for supplying air into the developer transfer path;
A developing device that transports the developer discharged from the supply device through the developer transfer path using the air supplied from the air supply source and transports the developer to the developing unit.
An air supply path for supplying air from the air supply source is connected to a transfer path on the discharge side of the supply device;
Between the discharge side of the supply device and the developer transfer path, the angle between the air flow direction in the developer transfer path and the upstream side in the air flow direction is fixed so as to be an acute angle. A developing device comprising a plate-like member. A developing unit that develops the latent image on the latent image carrier, a developer storing unit that is provided outside the developing unit and stores the developer, and a supply device that discharges the developer in the developer storing unit;
A developer transfer path for transferring the developer discharged from the supply device to the developing unit;
An air supply source for supplying air into the developer transfer path;
A developing device that transports the developer discharged from the supply device through the developer transfer path using the air supplied from the air supply source and transports the developer to the developing unit.
A plate-like member displaceable between a first position and a second position is provided between the discharge side of the supply device and the developer transfer path, and the plate-like member is at the second position from the first position. And a developing device which restricts the inflow of air from the developer transfer path to the supply device side. The developing device according to claim 1,
A developing device, wherein a plurality of the plate-like members are provided at intervals in the air supply direction. The developing device according to claim 2, wherein
The plate-like member is displaceable between a second position that restricts the inflow of air and a first position that allows the developer to be discharged by the supply device, and when the air is supplied, the plate-like member is A developing device, wherein the developing device is set at a second position for restricting inflow of air. The developing device according to claim 4.
The developing device, wherein the plate-like member is provided so as to maintain a first position where discharge of the developer is allowed, and is displaced to a second position where air inflow is restricted by air pressure when air is supplied. The developing device according to claim 4.
The development is characterized in that the plate-like member is provided so as to maintain a first position allowing discharge of the developer by its own weight, and is displaced to a second position where air inflow is restricted by air pressure when air is supplied. apparatus. The developing device according to claim 4.
A developing device comprising: a driving source that selectively sets the plate-like member to a second position for restricting inflow of air and a first position for permitting discharge. In the developing device according to any one of claims 4 to 7,
The developing device according to claim 1, wherein when the plate-like member is in a second position that restricts the inflow of air, the displaced end portion does not contact the periphery. In the developing device according to any one of claims 4 to 8,
A developing device characterized in that a valve is provided in an air supply path, and air is intermittently supplied by switching the valve.   An image forming apparatus comprising the developing device according to claim 1.

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