JP5396938B2 - Developing device and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device that performs development using a two-component developer comprising a toner and a carrier, a carrier, toner and developer used in the developing device, a process cartridge including the developing device, and the developing device Alternatively, the present invention relates to an image forming apparatus such as a copying machine, a printer, a plotter, a facsimile, or a complex machine including the process cartridge, which performs image formation using an electrophotographic method. The present invention further relates to an image forming apparatus including a plurality of the developing devices or the process cartridges and capable of color image formation.

  2. Description of the Related Art Conventionally, as a biaxial transport type developing device that performs development using a two-component developer, a developer transport member (screw, auger, etc.) for supplying and collecting developer to a developer carrier (developing roller (sleeve)) ) And the supply / recovery conveyance path, and the developer conveyance member (screw, auger, etc.) and the agitation conveyance path for conveyance agitation after toner replenishment, and the two conveyance paths. There is known a configuration in which these are arranged in a substantially horizontal direction below the developer carrier.

In recent years, downsizing of image forming apparatuses has been demanded, but it can be said that the conventional two-axis conveyance type developing apparatus has reached the limit of downsizing. If the developer can be transported on one axis, the size can be reduced by one screw. However, in the prior art, the toner is replenished only at one place in the longitudinal direction, and stirring is performed with a screw far from the developing sleeve. However, after the developer is conveyed to one of the longitudinal sides and the toner and the carrier are sufficiently mixed, the developer is supplied to the developing sleeve from the screw on the side close to the developing sleeve and conveyed in the opposite direction to the screw on the far side. Although the agitation function and the supply function are separated, two screws are essential because the developer must be circulated in the development unit for realization. That is, if there is only one screw, the developer is naturally biased to one longitudinal side.
If the toner is replenished over the entire length, the need to move the developer greatly with a screw is relatively less than when replenishing it to one place in the longitudinal direction. In order to stir, a stirring paddle was required in addition to one screw. For example, in the configuration disclosed in Patent Document 1, the entire surface is replenished in the longitudinal direction, and when the toner falls from the separator, it is moved in the lateral direction by the skew plate, and in addition to that, a screw that conveys in the opposite longitudinal direction is combined. Stir in the direction. However, since a screw and a paddle must be provided separately, there is a drawback that the apparatus is increased in size.
In the apparatus of Patent Document 1, the developer is conveyed in one of the longitudinal directions by a screw, and is conveyed in the opposite direction to the screw by a skew plate. There is also a paddle to stir the developer. Here, in order to reduce the size of the developing device, when the agitation paddle and the conveying screw are integrated to reduce the size, in the conventional configuration, the conveying ability in the direction opposite to the screw is compared with the conveying ability in the longitudinal direction of the screw. Is small, and the developer is biased to the downstream side in the screw conveying direction. In order to solve this problem, if the conveying ability of the screw is lowered, the developer moves only in a very narrow region in the longitudinal direction, so that density unevenness is generated when an image having a large difference in image area ratio in the longitudinal direction is output. Cause.

Further, in the conventional image forming apparatus represented by the biaxial conveyance type, the developer (mixture of carrier and toner) exists only in the vicinity of the developing sleeve, and the toner and the carrier are also stirred in the vicinity of the developing sleeve. There is a problem that the toner and the carrier are supplied to the sleeve without being sufficiently stirred. In addition, since a mechanism for stirring the toner and the carrier is incorporated in the developing device, the developing device itself is increased in size to complicate the apparatus configuration, and the operability during apparatus maintenance is reduced.
In order to solve the above-described problems, an invention is known in which a developer optimization unit and a developer circulation conveyance unit are separately provided, and the development device can be reduced in size and maintainability can be improved. In the image forming apparatus of Patent Document 2, the developer is transported and circulated between the developing unit and the developer optimizing unit that is separately provided at a location different from the developing unit. In the developer optimization means, the mixing ratio of the toner and the carrier is adjusted to optimize the toner concentration and charge amount of the developer, and the optimized developer is supplied to the developing device. It is not necessary to have a mechanism for optimizing the density, etc., the apparatus can be miniaturized, the internal configuration of the complex image forming apparatus is simplified, and there is a margin in the layout, facilitating maintenance. be able to.
However, when the developer is supplied to a simplified developing device using the developer optimizing means and the developer circulating and conveying means shown in Patent Document 2, the developer concentration is lowered once used for development. In some cases, the existing agent is supplied to the developing sleeve again before returning to the developer optimizing means. If development is performed at the same bias using an agent once used for development and having a low developer concentration, the toner adhesion amount on the photoreceptor is reduced, leading to a reduction in image density. In particular, when an image having a high image area ratio is printed, a large density reduction occurs on the downstream side of the developer conveyance, resulting in an image density deviation in the longitudinal direction.

In addition, when an image having a large difference in image area ratio in the longitudinal direction is output, as a cause of density unevenness, the developer may be brought to the developing sleeve. In Patent Document 3, the following three causes and countermeasures are taken. is suggesting.
Cause (1) After the developer is separated from the developer carrying member at one end, it rebounds on the unit side plate and is pumped up to the developer carrying member again.
Cause (2) Development in which a magnetic field for pumping up the developer is formed on the downstream side in the direction of movement of the developer carrier adjacent to the developer detachment site after the developed developer is separated from the developer carrier by one end. The developer must be pumped up again by the magnetic force of the developer pumping site on the surface of the developer carrier.
Cause (3) The developed developer is once separated from the developer carrier and dropped to the position of the developer supply member, and then pumped up again to the developer carrier without being stirred by the developer supply member.
As described above, in Patent Document 3, as a means for solving the three causes, the upper end is located below the portion set to the magnetic field for detaching the developer from the developer carrier surface, and the space on the side facing the developer carrier surface. There has been proposed a method in which a developer restricting plate is provided to partition the space from which the developer detached from the surface of the developer carrying member falls. (See FIG. 6 of Patent Document 3)
However, the developer regulating means proposed in Patent Document 3 can reduce density unevenness due to the accompanying developer, but it is premised on that it is applied to a biaxial transport type developing device. There is a limit to the miniaturization of the vessel.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a developing device that is small in size and capable of sufficiently stirring a developer and has no image density unevenness.

That is, the following problems are solved by the following inventions 1 to 7.
1. A developer carrying member for developing a latent image having a fixed magnet for holding a developer containing toner and a carrier by magnetic force, and supplying the developer to the developer carrying member from below the developer carrying member The developer supply member and the fixed magnet generate a region having a large normal magnetic flux density and a region having a small normal magnetic flux density, and after developing the electrostatic latent image with the developer in the region having the high normal magnetic flux density, the method In a region where the linear magnetic flux density is small, developer recovery means for separating the developer from the developer carrier and dropping it onto the developer supply member; and developer being separated from the developer carrier and supplying the developer In a developing device including a developing unit provided in a recovery path until being recovered to a member, and provided with a regulating member that regulates the path of the developer, the developer supply member is provided on the developer carrier. Develop in one of the longitudinal directions Serves as the first developer conveying means for conveying said regulating member, the developer carrying direction in the same direction by the first developer conveying means serves also as the second developer conveying means for conveying the developer The developer collecting and conveying means and the developer supplying and conveying means and the developer optimizing means connected thereto are provided outside the developing unit, and the developer collecting and conveying means and the developer supplying and conveying means are The developing device is connected to the developing unit via a developer discharge port and a developer supply port provided in the developing unit.

2. 2. The developing device according to claim 1, wherein the developer regulating member is a plate-like member inclined from a horizontal direction, and a skew plate having a plurality of parallel grooves formed on a surface thereof is provided. The developing device.
3. 3. The developing device according to the item 2, wherein the skew amount in the skew plate is equal to or greater than a parallel groove interval.
4). 4. The developing device according to any one of 1 to 3, further comprising a vibrating unit that contacts the developer regulating member and vibrates the regulating member.
5. 5. The developing device according to claim 4, wherein the vibration unit that contacts the regulating member has its vibration condition controlled by the developer conveying speed of the first developer conveying unit.
6). 6. A process cartridge using the developing device according to any one of 1 to 5 above.
7). An image forming apparatus using the developing device according to any one of 1 to 5 above.

  According to the present invention, it is possible to provide a small-sized developing device and an image forming apparatus free from uneven image density.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to the present invention. It is a schematic cross-sectional view showing the structure of a conventional general developing unit. FIG. 2 is a schematic cross-sectional view illustrating a structure of a developing unit according to the first embodiment of the present invention. FIG. 4 is a perspective view of a developer regulating transport plate according to the present invention. It is the figure which looked at the front side of the developer regulation conveyance board concerning the present invention from right above. It is the figure which looked at the back surface of the developer control conveyance board concerning this invention from right above. FIG. 2 is a schematic cross-sectional view showing a developer cycle according to the first embodiment of the present invention. FIG. 3 is a schematic diagram in a longitudinal direction showing a developer cycle according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view illustrating a structure of a developing unit according to a second embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a developer cycle according to a second embodiment of the present invention. It is a schematic diagram of the longitudinal direction which shows the developer cycle which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the developer stirring and circulation system which concerns on 2nd Embodiment. 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.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated based on drawing. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of an embodiment of the present invention, and does not limit the scope of the claims.
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to the present invention.
The image forming apparatus includes an intermediate transfer belt 56 in the approximate center of the inside thereof. The intermediate transfer belt 56 is an endless belt made of a heat-resistant material such as polyimide or polyamide and made of a base adjusted to a medium resistance, and is supported by being wound around four rollers 52, 53, 54, and 55. It is rotationally driven in the direction of arrow A. Below the intermediate transfer belt 56, four image forming units corresponding to yellow (Y), magenta (M), cyan (C), and black (K) toners are arranged along the belt surface of the intermediate transfer belt 56. It is out.
Below the four image forming units, there is provided an exposure device 9 that exposes the surface of each charged photoconductor based on image data of each color to form a latent image.
Primary transfer that primarily transfers the toner image formed on the photoreceptor 1 onto the intermediate transfer belt 56 at a position facing each photoreceptor 1 (1Y, 1M, 1C, 1K) with the intermediate transfer belt 56 interposed therebetween. Each roller 51 is arranged. The primary transfer roller 51 is connected to a power source (not shown) and is applied with a predetermined voltage.

A secondary transfer roller 61 is pressed against the outside of the portion of the intermediate transfer belt 56 supported by the roller 52. The secondary transfer roller 61 is connected to a power source (not shown) and is applied with a predetermined voltage. A contact portion between the secondary transfer roller 61 and the intermediate transfer belt 56 is a secondary transfer portion, and the toner image on the intermediate transfer belt 56 is transferred onto a transfer sheet.
An intermediate transfer belt cleaning device 57 for cleaning the surface of the intermediate transfer belt 56 after the secondary transfer is provided outside the portion of the intermediate transfer belt 56 supported by the roller 55.
Above the secondary transfer portion, a fixing device 70 is provided that fixes the toner image on the transfer paper semi-permanently to the transfer paper. The fixing device 70 includes a heating roller 72 having a halogen heater therein and an endless fixing belt 71 wound around the fixing roller 73, and a pressurization disposed so as to be opposed to and in pressure contact with the fixing roller 73 via the fixing belt 71. And a roller 74.
Below the image forming apparatus, there is provided a paper feeding device 20 for placing the transfer paper and feeding the transfer paper toward the secondary transfer unit. In FIG. 1, 21 is a paper feed roller, 91 is a paper discharge roller, and 200 is a toner bottle.
The image forming apparatus shown in FIG. 1 is a color quadruple tandem intermediate transfer method, and paper conveyance is an example in the vertical direction. By using the developing device of the present invention that has been reduced in size with the uniaxial stirring screw, the image forming apparatus can also be reduced in size.
The process cartridge of the present invention is a process cartridge in which a photosensitive member and a developing device that develops at least a latent image on the photosensitive member with a developer are integrated and detachable from the image forming apparatus. As the apparatus, the developing apparatus described in the present invention is used.

In the developing device of the present invention, a screw having a developer supplying / conveying function located below the developing sleeve is only used as a single shaft, and a regulating member provided at a position where the developer is separated from the developing sleeve extends the developer in addition to the regulating function. The longitudinal conveying direction is 180 ° opposite to the conveying direction of the developer conveyed by the conveying screw located below the developing sleeve.
As a result, the developer having a reduced toner density used for developing the latent image carried on the photosensitive member is surely separated from the developing sleeve by the regulating member, and at the same time moving in the longitudinal direction of the developing sleeve. Then, it falls to the conveying screw part under the developing sleeve. As a result, the developer after passing through the electrostatic latent image is not brought to the developing sleeve, and since the stirring in the longitudinal direction is completed with a single conveying screw, a small developing device having no density unevenness is provided. can do.
In the developing device of the present invention, a screw having a developer supplying / conveying function located below the developing sleeve is used as only one shaft, and a regulating member provided at a position where the developer is separated from the developing sleeve has a developer function in addition to the regulating function. In the longitudinal direction, and the longitudinal transport direction is the same as the transport direction of the developer transported by the transport screw located below the developing sleeve.
As a result, the developer used for developing the latent image carried on the photosensitive member and having a reduced toner concentration is surely separated from the developing sleeve by the regulating member, and at the same time, in the longitudinal direction of the developing sleeve (from the inside of the developing device). While moving in the direction of discharging the developer, the developer falls to the conveying screw part below the developing sleeve. This facilitates the discharge of the developer once used for development without the developer after passing through the electrostatic latent image being taken along the developing sleeve. And since the stirring in a longitudinal direction is completed with one conveyance screw, the small developing device without a density nonuniformity can be provided.

  In order to clarify the characteristics of the developing unit (developing unit) according to the present invention, first, the structure of a conventional developing unit and its problems will be described. FIG. 2 is a schematic cross-sectional view of a conventional developing unit for a typical two-component developing process. A developing roller 2 and developer stirring screws 3 and 4 are built in a casing 7 of the developing unit. The developing roller 2 includes an aluminum developing sleeve and a multipolar magnet fixedly installed inside. FIG. 2 shows the magnetic flux density in the normal direction of the magnetic field formed by the fixed magnet. Toner supplied from a toner supply port (not shown) is mixed with a carrier, stirred and charged for the first time in the developing machine to become a developer that can be developed. The developer is stirred and conveyed by the two developer stirring screws 3 and 4. The developer pumped up on the developing sleeve as the developing roller 2 rotates is scraped off by the doctor blade 5 and conveyed to the developing unit. A bias applying unit is connected to the developing sleeve, and an electrostatic field and an alternating electric field are formed between the developing sleeve and the photosensitive member 1, and development is performed. The developer that has completed the developing process is conveyed by the developing sleeve and returned to the developing unit. The developer returned into the developing unit is detached from the developing sleeve at the developer cutting pole (point A in FIG. 2). The separated developer is dropped into the stirring screw 3 without being re-pumped by the developer sleeve by the developer regulating plate 6 and is prepared for the next development opportunity.

The structure of the developing unit according to the first embodiment of the developing device of the present invention will be described with reference to FIG. In FIG. 3, a developing unit casing 7 contains a developing roller 2, a uniaxial developer stirring screw 3, a doctor blade 5, and a developer regulating transport plate 6a serving as a core of the present invention. The developer regulating transport plate 6a is inclined so that the developer separated from the developer cutting pole (point A in FIG. 3) falls again onto the developer stirring screw 3 by its own weight.
Hereinafter, the developer regulating transport plate 6a will be described in detail. 4, 5 and 6 show details of the developer regulating transport plate 6a. FIG. 4 shows a perspective view of the developer regulating transport plate 6a, and FIG. 5 shows a view seen from directly above. The developer regulating transport plate 6 a has a rectangular so-called general blade shape, and the developer regulating transport plate 6 a on the surface on the developing unit casing 7 side (referred to as the front surface) is a developer. Is a slanting plate provided with a plurality of slanted grooves in parallel so as to convey the toner in the longitudinal direction of the developing sleeve.

  In order to efficiently convey the developer in the longitudinal direction, it is preferable that the skew amount α (FIGS. 4 and 5) of the skew plates is greater than or equal to the skew plate interval β (α ≧ β). The reason is that the developer separated from the sleeve is upstream of the developer moving direction on the skew plate, and the angle formed by the convex portion of the skew plate in the transport direction and the longitudinal direction of the skew plate is an acute angle. When located at a certain point D, even in a skew plate where α <β, the drop direction is regulated by the convex portion and the sheet is conveyed in the longitudinal direction, but the developer separated from the sleeve is If the angle formed between the convex portion of the skew plate in the transport direction and the longitudinal direction of the skew plate on the row plate is an obtuse angle, α <β The slanting plate is not conveyed in the longitudinal direction because it falls without contacting the convex portion. For this reason, it is preferable that the skew amount α (FIGS. 4 and 5) of the skew plate is not less than the skew plate interval β (α ≧ β).

FIG. 6 is a view of the surface of the developer regulating transport plate 6a on the side of the doctor blade 5 (back surface) viewed from directly above. A plurality of vibrators 8 that vibrate the developer regulating transport plate 6a are arranged on the back surface of the developer regulating transport plate 6a. The vibrator 8 is a vibration generator using a piezoelectric element typified by piezo or a small motor.
7 and 8 are schematic views of the developer circulation cycle. The developer in the vicinity of point B in FIG. 7 moves to the developing sleeve by a magnetic field (pumping pole) formed from a fixed magnet ((1)). After the development of the electrostatic latent image on the photoreceptor 1 is completed, the developer with reduced toner density is separated from the developing sleeve at the developer cutting pole (point A in FIG. 7), and the developer regulating transport plate 6a 8 moves to the right in the longitudinal direction ((2)) shown in FIG. 8 by hopping due to the developer's own weight and vibration, and falls onto the stirring screw 3. The dropped developer is moved to the left ((3)) in the longitudinal direction shown in FIG. 8 by the stirring screw 3, and the cycle of moving again to the developing sleeve at the pumping pole is repeated. At this time, the shape of the stirring screw 3 and the developer regulation are set so that the developer conveyance amount to the right ((2)) in the longitudinal direction and the developer conveyance amount to the left ((3)) in the longitudinal direction are the same. Appropriate design parameters such as the shape of the front surface of the transport plate 6a and the installation angle of the developer regulating transport plate 6a are adjusted.
The vibrator 8 can control the developer conveyance amount on the front surface of the developer regulating conveyance plate 6a. For example, when the vibrator 8 is a vibration generator using a small motor, the rotational speed of the motor is variable when the process linear speed is the standard speed and half the speed. The motor speed is increased at the standard speed, and the motor speed is decreased at the half speed so that the developer transport amount by the developer regulating transport plate 6a and the developer transport amount by the stirring screw 3 are always the same. To do. By doing so, the developer amount balance in the longitudinal direction of the stirring screw 3 can be kept uniform.

The structure of the developing unit according to the second embodiment of the developing device of the present invention will be described with reference to FIG. In FIG. 9, a developing unit casing 7 contains a developing roller 2, a uniaxial developer stirring screw 3, a doctor blade 5, and a developer regulating transport plate 6a which is a core of the present invention. The developer regulating transport plate 6a is inclined so that the developer separated from the developer cutting pole (point A in FIG. 9) falls again onto the developer stirring screw 3 by its own weight. The developer regulating transport plate 6a is as described above.
10 and 11 are schematic views of the developer circulation cycle. The developer in the vicinity of point B in FIG. 10 moves to the developing sleeve by a magnetic field (pumping pole) formed from a fixed magnet ((1)). After the development of the electrostatic latent image on the photoreceptor 1 is completed, the developer with reduced toner density is separated from the developing sleeve at the developer cutting pole (point A in FIG. 10), and the developer regulating transport plate 6a 11 moves to the right ((2)) in the longitudinal direction shown in FIG. 11 by hopping due to the developer's own weight and vibration, and falls onto the stirring screw 3. The dropped developer is further moved and stirred to the right in the longitudinal direction ((3)) shown in FIG. 11 by the stirring screw 3, and again moves to the developing sleeve at the pumping pole.

Then, after the developer cycle is repeated, the developer is returned from the developer discharge port 103 to the developer optimizing unit 100 by the developer collecting / conveying unit 101. The developer optimized by the developer optimizing unit 100 is supplied from the developer supply port 104 to the developing unit by the developer supply / conveying unit 102.
In the second embodiment, the developer once used for development and having a reduced toner density is not re-pumped to the developing sleeve and is discharged out of the developing unit more quickly than the developer not used for development. As a result, the toner concentration of the developer in the developing unit can be made uniform in the longitudinal direction.

As the developer optimizing unit 100, the developer collecting / conveying unit 101, and the developer supplying / conveying unit 102, a developer agitation / circulation system described in JP-A-2009-31586 can be applied. This developer agitation / circulation system will be described with reference to FIGS.
As illustrated in FIG. 12, the developing device 105 includes a developing unit 150 that develops the electrostatic latent image on the photoreceptor 1 and a stirring unit 151 that performs stirring according to the state of the developer at a position away from the developing unit 150. A toner cartridge 152 for supplying toner to the agitating unit 151, a rotary feeder 153 provided below the agitating unit 151, an air pump 154 as a developer circulation drive source for conveying the developer by air pressure, and the like. doing.
The developing unit 150 and the stirring unit 151 are connected by a circulation path 155, and the rotary feeder 153 and the developing unit 150 are connected by a circulation path 156. The toner cartridge 152 and the stirring unit 151 are connected by a toner supply path 157, and the air pump 154 and the rotary feeder 153 are connected by a pipe line 158.
In FIG. 12, reference numeral 159 denotes a motor as a toner replenishment drive source, 160 denotes a motor as an agitation drive source, and 161 denotes a motor as a drive source of the rotary feeder 153.

The developed developer is conveyed from the discharge port 167 provided in the developing unit 150 to the stirring unit 151 through the circulation path 155. A toner concentration detection unit (not shown) is installed on the most downstream side of the stirring screw in the developing unit 150, and toner is supplied from the toner cartridge 152 based on the signal.
Toner supply is performed by rotating a screw (not shown) in the toner supply path 157 by the motor 159. Toner replenishment is performed at a site immediately before the entrance of the stirring unit 151 in the circulation path.
In the stirring unit 151, 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. 13, the developer passes through the discharge port 170 formed in the lower portion of the stirring unit 151 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 156, and is supplied again to the developing unit 150 through the receiving port 168.

FIG. 13 is a cross-sectional view of the stirring unit 151. A developer supply port 169 is provided on the upper surface of the stirring unit 151 and a discharge port 170 is provided on the lower surface. The stirring unit main body 151a has an inverted conical shape whose diameter decreases toward the discharge port 70. ing.
A screw 171 that conveys the developer from the bottom to the top is provided in the center of the stirring unit main body 151a, and two rotatable stirring members 172 are provided on the outside thereof. The agent is stirred and mixed.
The outer stirring member 172 and the screw 171 are rotated by a motor 160. The screw 171 is directly connected to the motor 160, and the outer stirring member 172 rotates via the reduction gear trains 173a to 173d. As shown in FIG. 13A, the stirring member 172 is fixed obliquely to a support portion 174 that is directly connected to the reduction gear train.
The conveyance from the replenishment port 169 to the discharge port 170 in the stirring unit 151 uses gravity. Since the developer is always present as a buffer in the stirring unit 151, the unmixed developer is not discharged as it is.
The rotary feeder 153 includes a rotor 175 that is rotated by a motor 161 (see FIG. 12) and has a plurality of radially extending blades 175a, and a stator 176 that covers the rotor 175. The rotary feeder 53, the circulation path 56, and the pipe line 158 are connected by a joint pipe line 177.

FIG. 14 is a schematic diagram illustrating the flow of the developer during stirring in the stirring unit 151.
The developer lifted upward from the bottom in the direction of the arrow A by the rotation of the screw 171 moves in the direction of the arrow B along with the rotation of the stirring member 172 that rotates on the outside, and is gathered around the screw 171 again.
As described above, the developer is constantly convected in the stirring portion 151. By this convection, the entire container (inside the stirring unit main body 151a) 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.
It has been found that the contact probability is increased by convection of the developer in the stirring portion 151, and the damage to the developer is small.

Next, the rotary feeder unit will be described in detail.
As shown in FIG. 15, the rotor 175 and the stator 176 of the rotary feeder 153 are provided with a clearance between the tip of the blade 175a of the rotor 175 and the inner surface of the stator 176, as described above. If there is a gap with the stator 176, a part of the air generated from the air pump 154 passes through this gap and flows into the stirring unit 151, and the air for sending the developer to the developing unit 150 decreases (the pressure is reduced). descend).
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 transport the developer discharged from the rotary feeder 153, it is preferable not to allow the air of the air pump 154 to flow into the stirring unit 151 as much as possible.

Therefore, in this embodiment, a plate-like air inflow restriction that restricts the inflow of air to the rotary feeder 153 side between the discharge side of the rotary feeder 153 and the developer transfer path (here, in the joint pipe line 77). A member 180 was placed. Three air inflow regulating members 180 are fixedly arranged at intervals in the air supply direction.
When the air sent from the air pump 154 reaches the inside of the joint pipe 77 as the mixing section, the air transferred to the developing section 150 together with the developer in the circulation path 56 and the reverse flow to the upper rotary feeder 153 side. Although there is air, the air inflow regulating member 180 regulates the flow of air, so that the air flowing backward to the rotary feeder 153 side is reduced.
Since the air inflow restricting member 180 is installed so that the upper end thereof is inclined toward the air pump 154 side and the angle θ formed with the horizontal line is an acute angle, the air inflow restricting member 180 restricts the air flow toward the rotary feeder 153 side. High effect. The developer discharged from the rotary feeder 153 falls between the air inflow restricting member 180 and the joint pipe 77 inner surface and between the air inflow restricting members 180. Although one air inflow restricting member 180 may be provided, the air inflow restricting function is higher when a plurality of air inflow restricting members 180 are provided.
As the rotary feeder 153, the second embodiment, the third embodiment, and the fourth embodiment described in JP2009-31586A can also be used.

1 Photosensitive member 2 Developing roller 3 Stirring screw (first shaft)
4 Stir screw (second shaft)
5 Doctor blade 6 Developer restriction plate 6a Developer restriction transport plate 7 Development unit casing 8 Vibrator 20 Paper feed tray 21 Paper feed roller 51 Primary transfer roller 52 Primary transfer drive roller 53 Paper entrance roller 54 Primary transfer backup roller 55 Primary transfer Follower roller 56 Intermediate transfer belt 57 Transfer belt cleaning device 61 Secondary transfer roller 70 Fixing device 71 Fixing belt 72 Fixing tension roller 73 Heating roller 74 Pressing roller 91 Discharging roller 100 Developer optimizing means 101 Developer collecting and conveying means 102 Developer supply / conveying means 103 Developer discharge port 104 Developer supply port 105 Developing device 150 Developing unit 151 Stirring unit 153 Rotary feeder 175 Rotor 176 Stator 180 Air inflow regulating member 200 Toner bottle

Japanese Patent Laid-Open No. 08-041822 Japanese Patent No. 3733496 JP 2005-148366 A

Claims (7)

A developer carrying member for developing a latent image having a fixed magnet for holding a developer including toner and a carrier by magnetic force;
A developer supply member for supplying a developer to the developer carrier from below the developer carrier;
The fixed magnet generates a region having a large normal magnetic flux density and a region having a small normal magnetic flux density, and after developing the electrostatic latent image with the developer in the region having the high normal magnetic flux density, the region having the small normal magnetic flux density. A developer recovery means for separating the developer from the developer carrier and dropping the developer onto the developer supply member;
Development provided with a developing unit provided with a regulating member that is located in a collection path from when the developer is separated from the developer carrier and collected by the developer supply member, and that regulates the path of the developer In the device
The developer supply member also serves as a first developer transport means for transporting the developer to one of the longitudinal directions of the developer carrier.
The regulating member also serves as a second developer conveying means for conveying the developer in the same direction as the developer conveying direction by the first developer conveying means,
Outside the developing unit, a developer recovery transport unit and a developer supply transport unit, and a developer optimization unit connected thereto, are provided. The developer recovery transport unit and the developer supply transport unit are connected to the development unit. A developing device, wherein the developing device is connected to a developing unit via a developer discharge port and a developer supply port provided in the unit. The developing device according to claim 1,
The developing device, wherein the developer regulating member is a plate-like member inclined from a horizontal direction, and a skew plate having a plurality of parallel grooves formed on a surface thereof is provided. The developing device according to claim 2,
The developing device, wherein an amount of skew in the skew plate is equal to or greater than a parallel groove interval. In the developing device according to any one of claims 1 to 3,
A developing device comprising: a vibrating means that contacts the developer regulating member and vibrates the regulating member. The developing device according to claim 4,
The developing device is characterized in that the vibration condition of the vibrating means contacting the regulating member is controlled by the developer conveying speed of the first developer conveying means. A process cartridge using the developing device according to claim 1. An image forming apparatus using the developing device according to claim 1.

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