JP2014106423A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that includes a stirring unit provided separately from a developing unit and conveys and circulates a developer by using air pressure, and can prevent an increase in pressure inside the developing device for a long period.SOLUTION: A developing device 5 has: a developer inflow port 82 through which a developer G inflows, which is conveyed by developer conveyance units including an air pump 54 and a circulation path 56; a communication port 83 that communicates with a stirring unit 51; and an exhaust unit 84 that exhausts air to the outside of the device, and includes an air processing chamber 80 that has a supply port 85, at a lowermost part, for supplying the developer G flowing from the developer inflow port 82 to a supply and conveyance path 68, and has a cylindrical inner wall surface 80a formed thereon. The air processing chamber 80 has: the developer inflow port 82 and the communication port 83 provided to be in contact with a peripheral surface of the inner wall surface 80a from a tangential direction; the exhaust unit 84 provided above the developer inflow port 82 and communication port 83; and the supply port 85 communicated with an upper part of the supply and conveyance path 68.

Description

  The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile machine, a plotter, etc., or a multifunction machine having at least two functions.

  An apparatus for developing and visualizing an electrostatic latent image formed on a latent image carrier using a two-component developer (hereinafter also simply referred to as a developer) having a toner and a carrier as a developing device. It has been known. In this developing device, the developer in which the developing process is completed in the developing region and the toner is consumed is collected, mixed with the replenished toner, stirred, and again used for development. 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 including 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, the toner is dispersed and charged by utilizing the stirring effect of the rotation of two screws during a short time until the replenished toner is pumped up to the developing sleeve. For this reason, particularly when the toner balance is large, the replenished toner is not sufficiently dispersed but is pumped up to the developing sleeve, causing 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 in accordance with the state of the developer. 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 and 2).

  In the developing devices described in Patent Documents 1 and 2, the developer that has been developed is collected from the developing unit through the circulation path to the stirring unit. To adjust the toner density in the agitation unit and sufficiently disperse the replenished toner, toner replenishment is performed on the agitation unit or a circulation path between the developing unit and the agitation unit upstream of the agitation unit. This is done by connecting roads.

The main configuration in the case where a separate stirring unit is provided in a place away from the developing unit and the developer is conveyed between the developing unit and the stirring unit using air is the developer storage unit (stirring unit), the developer An air supply source such as a supply unit (lower end of the stirring unit), a circulation path, or the like. Since the developer is transported using the air pressure (positive pressure) and the flow velocity, a differential pressure is generated between the air transport source and the transport destination (atmospheric pressure).
Since the developer sent to the developing unit is circulated such that it is collected in the developer storage unit through the circulation path and transported again, the circulation path and the developer storage unit are also at atmospheric pressure. A rotary feeder is generally used as a supply device in a developer supply unit. The developer adjusted and optimized in the agitation unit is conveyed and transferred to the developing unit by air pressure while the discharge amount is regulated by a rotary feeder.

In Patent Document 1, a separate agitation unit is provided at a location away from the development unit, and the agitation unit performs agitation in accordance with the state of the developer. A developing device that supplies the developing unit is disclosed. The developing device having such a configuration has the following problems.
That is, in a developing device that transports and circulates developer using air, air supply means such as an air pump takes in air used for transporting the developer from the outside of the developing device. Therefore, the pressure in the developing device increases due to the air used for transporting the developer. When the internal pressure in the developing device rises, the internal pressure balance in the developing device is lost, and the resulting internal pressure difference makes it difficult to transport and circulate the developer, or make it impossible to replenish toner properly. Such problems occur. Therefore, in order to prevent the internal pressure from increasing, it is necessary to exhaust air to the outside of the developing device.

  In Patent Document 2, a cylindrical air processing chamber (a cylindrical portion (8) of the discharge portion (8B) in FIG. 4) is provided in the developer supply portion (developer charging portion (6) in FIG. 4) of the developing device. An provided air treatment mechanism is disclosed. Further, a configuration in which a filter (10) for capturing toner separated from a carrier and allowing only air to pass through is disposed in the cylindrical portion (8) of the discharge portion (8B) of Patent Document 2. .

  However, the air processing mechanism disclosed in Patent Document 2 is configured to perform only the processing of the air used for transporting the developer. Therefore, for example, in the case of using a rotary feeder that sends a developer obtained by stirring and mixing developer after development and replenished toner in the stirring section, the stirring section of the stirring section due to air leakage from the rotary feeder to the stirring section. The internal pressure rises, that is, the internal pressure rises in the developing device.

  Also, considering the arrangement of the filter (10) of Patent Document 2, simply considering an air treatment mechanism including a filter above the stirring unit, the internal pressure of the stirring unit increases due to the air leakage from the rotary feeder to the stirring unit. Can not prevent. In addition, if the developer and air are simply separated using only the filter, the exhaust performance is deteriorated at an early stage due to clogging of the filter, and as a result, the internal pressure in the developing container increases.

  The present invention has been made in view of the above-described circumstances, and includes a stirring unit arranged separately from the developing unit, and in the developing device that transports and circulates the developer using air pressure, The main purpose is to prevent an increase in internal pressure over a long period of time.

In order to solve the above-mentioned problems and achieve the above-mentioned object, the present invention employs the following characteristic means / invention-specific matters (hereinafter referred to as “configuration”).
The present invention provides a developing unit that develops a latent image on a latent image carrier, a stirring unit that is disposed outside the developing unit and that contains a part of the developer and stirs the developer, and the stirring unit. In the developing device including a developer transport unit that transports the agitated developer to the developing unit using air pressure, the developing unit carries the developer on the surface and can carry the developer. And a developer inlet port through which the developer conveyed from the developer conveying unit flows in, and a supply conveying path for supplying the developer conveyed from the developer conveying unit to the developer carrying member. A communication port that communicates with the agitation unit and an exhaust unit that discharges air to the outside of the apparatus, and a supply port that supplies the developer flowing in from the developer inflow port to the supply conveyance path at the bottom. An air treatment chamber formed with a cylindrical inner wall surface, and the air treatment chamber has a front The developer inlet and the communication port are provided so as to contact the peripheral surface of the inner wall surface from the tangential direction, and the exhaust part is provided above the developer inlet and the communication port. The supply port of the air treatment chamber is communicated with the upper part of the supply conveyance path.

  According to the present invention, the above-described problems can be solved and a new developing device can be provided. That is, according to the present invention, the above configuration can suppress an increase in internal pressure in the developing device over a long period of time.

1 is a schematic front view illustrating a configuration of an image forming apparatus illustrating an embodiment of the present invention. 1 is a perspective view illustrating an overall configuration of a developing device showing an embodiment of the present invention. It is sectional drawing which shows the structure of the image development part of the said one Embodiment. FIG. 2 is a cross-sectional view around a stirring unit and a rotary feeder of the developing device according to the embodiment. It is sectional drawing of the supply conveyance path | route of the image development part connected to the air processing chamber of the said one Embodiment, and an air processing chamber. (A) is a plane cross-sectional view of the connection portion between the circulation path and the developer inlet of the air processing chamber and the air processing chamber of the embodiment, and (b) is a communication path and air processing chamber of the embodiment. It is a plane sectional view of a connection part and an air treatment chamber of this. It is sectional drawing of the supply conveyance path | route and air processing chamber explaining the modification of the said one Embodiment.

  Hereinafter, embodiments of the present invention including examples will be described in detail with reference to the drawings. In each of the embodiments and modifications, components (members and components) having the same function and shape are described once by giving the same reference numerals after having been described unless there is a possibility of confusion. Omitted. In order to simplify the drawings and the description, even if the components are to be represented in the drawings, the components that do not need to be specifically described in the drawings may be omitted as appropriate. In the case of quoting and explaining constituent elements such as published patent gazettes, the reference numerals including the above-described background art are shown in parentheses to distinguish them from those of the embodiments.

First, a schematic configuration of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic front view showing the configuration of an image forming apparatus showing an embodiment of the present invention. In FIG. 1, only a developing unit, which will be described later, constituting the developing device 5 is illustrated for the sake of simplicity.
The image forming apparatus shown in FIG. 1 is an image forming apparatus having an electrophotographic configuration. An intermediate transfer unit 10 having an intermediate transfer belt 8 as a transfer image carrier or an intermediate transfer member is disposed at the approximate center of the image forming apparatus. The intermediate transfer belt 8 is supported by a plurality of illustrated support rollers so as to be able to run and rotate in the direction of the arrow in the figure.
Opposing the lower surface of the intermediate transfer belt 8, image forming units 6Y, 6M, 6C, and 6Bk corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel. These image forming units 6Y, 6M, 6C, and 6Bk have the same configuration except that the color of the toner used in the image forming process is different. For this reason, in the following description, the subscripts Y, M, C, and Bk that indicate the color of each color toner are omitted as appropriate.

  Each image forming unit 6 includes a drum-shaped photoconductor 1 as a latent image carrier, a charging device (not shown) provided around the photoconductor 1 (meaning to be provided), a developing device 5, and the like. The cleaning device is not shown. An image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photoreceptor 1, and a desired toner image is formed on the photoreceptor 1. The photosensitive member 1 is rotationally driven in a clockwise direction in the drawing by a driving unit (not shown), and the surface is uniformly charged at the position where the charging device is disposed (charging step).

  Thereafter, the surface of the photoreceptor 1 reaches an irradiation position of a laser beam emitted from an exposure section (not shown), and an electrostatic latent image is formed by exposure scanning at this position (exposure process). Thereafter, the surface of the photoconductor 1 reaches a position facing the developing device 5, and toner is attached to the electrostatic latent image on the photoconductor 1 and developed at this position to form a desired toner image (development). Process). Thereafter, the surface of the photoreceptor 1 reaches a position facing the intermediate transfer belt 8 and the primary transfer bias roller 9, and the toner image on the photoreceptor 1 is transferred onto the intermediate transfer belt 8 at this position (1). Next transfer process).

  Thereafter, the surface of the photoreceptor 1 reaches a position facing the cleaning device, and untransferred toner remaining on the photoreceptor 1 is collected at this position (cleaning step). After cleaning, the potential of the surface of the photoreceptor 1 is initialized by a neutralizing roller (not shown). In this way, a series of image forming processes performed on the photosensitive member 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, a laser beam based on image information is sent from an exposure unit (optical writing device) (not shown) arranged below each image forming unit 6Y, 6M, 6C, 6Bk to each image forming unit 6Y, 6M, 6C. , 6Bk on the photoreceptors 1Y, 1M, 1C, 1Bk. Thereafter, the toner images of the respective colors formed on the photoreceptors 1Y, 1M, 1C, and 1Bk 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 photoreceptors 1Y, 1M, 1C, and 1Bk to form a primary transfer nip portion. 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 travels in the direction of the arrow in the figure, and sequentially passes through the primary transfer nip portions of the primary transfer bias rollers 9Y, 9M, 9C, and 9Bk. In this way, the toner images of the respective colors on the photoreceptors 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 paper P as a recording medium conveyed to the position of the secondary transfer nip portion. Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

  On the other hand, a plurality of transfer papers P are stored in a paper supply unit 26 disposed in the lower part of the apparatus main body 100 and are separated and fed one by one by a paper supply 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 by the registration roller pair 28 toward the secondary transfer nip portion at a predetermined timing. As described above, a desired color image is transferred onto the transfer paper P at the secondary transfer nip portion.

  The transfer paper P on 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 transferred by heat and pressure from the fixing roller and the pressure roller. It is fixed. After the fixing, the transfer paper P is discharged as an output image to the paper discharge unit 30 formed in the cylinder space above the apparatus main body 100 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, reference numeral 32 denotes an image reading unit.

With reference to FIGS. 2 to 6, an embodiment according to the developing device of the present invention will be described in detail. FIG. 2 is a perspective view showing the overall configuration of the developing device 5 showing an embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a configuration of the developing unit 50. FIG. 4 is a cross-sectional view around the stirring unit 51 and the rotary feeder 53.
The developing device 5 of the present embodiment has a specific configuration including a developer stirring and circulation system. As shown in FIG. 2, the developing device 5 includes a developing unit 50, a stirring unit 51, a toner cartridge 52, a rotary feeder 53, an air pump 54 that constitutes a developer conveying unit described later. The developing unit 50 has a function of developing the electrostatic latent image on the photoreceptor 1, and the stirring unit 51 is provided separately from the developing unit 50, and performs stirring according to the state of the developer at a position away from the developing unit 50. The toner cartridge 52 has a function for supplying toner to the stirring unit 51. The rotary feeder 53 is provided below the stirring unit 51 and has a function to be described later. The air pump 54 constituting the developer conveying unit has a function of conveying the developer stirred by the stirring unit 51 to the developing unit 50 using air pressure. The air pump 54 functions as a developer circulation drive source.
In FIG. 1, only the developing unit 50 is shown for the sake of simplicity, and the other components described above are not shown.

  The developing unit 50 and the agitation unit 51 are connected and connected via a circulation path 55, and the rotary feeder 53 and the developing unit 50 are connected and connected via a circulation path 56 and the like. The toner cartridge 52 and the agitation unit 51 are connected and connected via a toner supply path 57, and the air pump 54 and the rotary feeder 53 are connected and connected via a pipe line 58. 2, 59 denotes a motor as a toner replenishing 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. 3, the developing unit 50 includes a casing 62 that constitutes a developing device, conveying screws 63 and 64 that are rotatably supported in the casing 62 and have helical fins, and a developing roller 65. doing.
The developing roller 65 is also called a developing sleeve, and functions as a developer carrying member which can carry and rotate the developer on the outer peripheral surface. The developing roller 65 has a well-known configuration in which a magnet is disposed inside and functions to attract and convey the developer to adhere toner to the electrostatic latent image on the photoreceptor 1.
In the casing 62, a two-component developer including toner and carrier is mixed and stored. The developer is circulated and conveyed in the casing 62 by the conveying screws 63 and 64. In the figure, the developer is conveyed from the front side to the back side in the figure by an upper conveying screw 63, and a part of the developer is sucked and attracted by a magnetic force by a developing roller 65, and is evenly uniformed by a doctor blade 66. After that, it contacts the photoreceptor 1. As a result, the toner adheres to the electrostatic latent image on the outer peripheral surface of the photoreceptor 1 and is developed to form a toner image.

  As shown by the arrow in FIG. 2, the developer after development passes through the circulation path 55 connected to and connected to the end of the collection conveyance path 67 (see FIG. 3) containing the conveyance screw 64, and enters the stirring section 51. Be transported. A toner density detecting means (not shown) is installed on the most downstream side of the collection conveyance path 67, and new toner is replenished from the toner cartridge 52 based on the signal. The toner supply is performed by rotating a screw (not shown) (see FIG. 4) in the toner supply path 57 by the motor 59. Toner replenishment is performed in the circulation path 55 just before the entrance of the agitation unit 51.

  As shown in FIG. 4, in the stirring unit 51, the developer after development and the replenished toner are stirred and mixed, so that the developer G having an appropriate toner concentration and charge amount is obtained. The developer G is sent to the joint pipe line 77 through the rotary feeder 53, passes through the circulation path 56 together with the air flow generated by the air pump 54 and sent through the pipe line 58, and is supplied to the developing unit 50 again. . An air processing chamber 80 is provided in an upper portion of a supply conveyance path 68 including a conveyance screw 63 serving as a developer supply unit in the developing unit 50. The air processing chamber 80 is connected to and connected to a circulation path 56 and a communication path 81 that communicates with the upper portion of the stirring unit 51. Details of the air treatment chamber 80 will be described later.

As shown in FIG. 4, a developer replenishing port 69 is provided in the upper part of the stirring unit 51, and a discharge port 70 is provided in the lower part. The stirrer body 51a has an inverted conical shape with a diameter that decreases toward the discharge port 70.
A screw 71 that conveys the developer G from the bottom to the top is provided at the center in the stirring unit main body 51a, and two rotatable stirring members 72 are provided on the outside thereof, and the rotating operation of these stirring members 72 is provided. To stir and mix the developer. The outer stirring member 72 and the screw 71 are rotated by the motor 60. The stirring shaft 71 a to which the screw 71 is attached is directly connected to the motor 60, and the outer stirring member 72 rotates via the reduction gear train 73.
Conveyance from the developer supply port 69 of the stirring unit 51 to the discharge port 70 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 that is rotated by a motor 61 and has a plurality of blades 75 a that extend radially, and a stator 76 that covers the rotor 75. The rotor 75 and the stator 76 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. By exchanging the developer and air due to the supply operation when the rotor 75 rotates, or because the sealing performance between the rotor 75 and the stator 76 is insufficient, air from the air pump 54 that is an air supply source leaks due to a pressure difference. It passes through the rotary feeder 53 and flows out to the stirring unit 51.
As described above, since the communication path 81 communicating with the air processing chamber 80 provided on the supply conveyance path 68 of the developing unit 50 is provided at the upper part of the stirring unit 51, the stirring unit 51 passes through the rotary feeder 53. The air that has flowed out into the air processing chamber 80 is also processed in the air processing chamber 80.

With reference to FIGS. 5 and 6, the configuration and operation around the air treatment chamber 80 of the present embodiment will be described. FIG. 5 is a cross-sectional view of the supply conveyance path 68 of the developing unit 50 and the air processing chamber 80 that are connected to the air processing chamber 80. FIG. 6A is a sectional view of the developer inlet 82 portion of the air processing chamber 80 and the air processing chamber 80 that are connected to the circulation path 56 as viewed from above. FIG. 6B is a cross-sectional view of the air treatment chamber 80 and the air treatment chamber 80 connected to the communication path 81 as viewed from above.
As described above, the air processing chamber 80 is provided above the supply conveyance path 68 of the developing unit 50. As shown in FIG. 5, the air processing chamber 80 is formed with a cylindrical inner wall surface 80 a at the upper portion and an inverted conical inner wall surface shape with a lower diameter toward the supply conveyance path 68. ing. The cylindrical side wall portion of the air processing chamber 80 is connected to a developer inlet 82 connected to a circulation path 56 that is a developer supply path and a communication path 81 that communicates with an upper portion of the agitation unit 51. A mouth 83 is provided integrally. In FIG. 5, 82 a is an opening portion to the inner wall surface 80 a of the developer inlet 82 provided integrally on the side wall portion of the air processing chamber 80, and 83 a is integrally provided on the side wall portion of the air processing chamber 80. Opening portions to the inner wall surface 80a of the communication port 83 are shown.

In addition, an exhaust part 84 including a filter 84 a as an example of a filter member is provided on the upper wall surface of the air treatment chamber 80. A supply port 85 for supplying the developer G flowing in from the developer inlet 82 is formed in the lower portion of the air processing chamber 80, and is connected to the supply conveyance path 68 through the supply port 85.
As the filter 84a, a filter using a nonwoven fabric whose eyes are smaller than the toner is used.

The developer inflow port 82 and the communication port 83 are provided so as to contact the inner peripheral surface of the cylindrical inner wall surface 80a of the air processing chamber 80 from the tangential direction. As shown in FIGS. 5 and 6, the developer G conveyed through the circulation path 56 together with the air flow air from the stirring unit 51 flows in from the developer inflow port 82, and as indicated by an arrow F, in the air processing chamber 80. A rotational (turning) force is applied in such a manner as to follow the curved surface of the inner wall surface 80a. The developer G moves to the supply port 85 side to the supply conveyance path 68 connected to the lower part while rotating along the inner wall surface 80a of the air processing chamber 80 due to the centrifugal force and its own weight due to the rotation.
Here, since the lower portion of the air processing chamber 80 has an inverted conical shape, the developer G does not fall and does not leave the inner wall surface 80 a until reaching the supply port 85. Due to the movement of the developer G, scattering and flying of the developer G can be suppressed. On the other hand, the air air is exhausted upward from the exhaust part 84 provided with the filter 84a while rotating upward. As a result, the separability between the two becomes high, the scattering of the developer G to the exhaust part 84 provided on the upper wall surface of the air processing chamber 80 can be suppressed, and the inside of the developing device 5 due to the clogging of the filter 84a. The increase in internal pressure can be suppressed over a long period of time.

  Further, the air that has flowed through the rotary feeder 53 and has flowed into the stirring unit 51 also flows into the air processing chamber 80 through the communication port 81 that communicates with the upper portion of the stirring unit 51. A large amount of developer scattered by the stirring operation is also taken into the air that has passed through the stirring unit 51, but the communication port 83 connected to the communication path 81 provided in the air processing chamber 80 is also the developer inlet 82 described above. It has the same configuration as. As a result, the developer G and the air air are separated in the air processing chamber 80, and the developer G falls from the supply port 85 to the supply conveyance path 68, so that the internal pressure in the developing device 5 increases due to clogging of the filter 84a. It can be suppressed for a long time.

(Modification)
A modification of the above embodiment will be described with reference to FIG. This modification is different from the above embodiment only in that the mounting angles of the developer inlet 82 and the communication port 83 of the air processing chamber 80 are inclined obliquely downward.
As shown in FIG. 7, a developer inlet 82 to which a circulation path 56 that is a developer supply path is connected, and a communication port 83 to which a communication path 81 that communicates with the upper portion of the stirring unit 51 is connected. The mounting angle with respect to the air treatment chamber 80 is inclined downward from the horizontal. Thereby, the developer G can more easily flow along the inner wall surface 80a of the air processing chamber 80, and the scattering and flying of the developer can be further suppressed as compared with the above-described embodiment. As an attachment angle, it has been found that an inclination angle of about 5 ° downward from the horizontal direction is preferable through experiments and the like.

  Further, a communication port 83 to which a communication path 81 communicating with the upper part of the stirring unit 51 is connected is provided immediately above the developer inlet 82 to which a circulation path 56 that is a developer supply path is connected. . As a result, according to the present modification, the developer taken in through the stirring unit 51 is taken in immediately into the developer flowing in from the developer inlet 82 immediately below, so that the developer is further increased than in the above embodiment. G scattering and flying can be suppressed.

The embodiment and the modification described above are examples of the present invention, and the present invention has a specific effect for each of the following modes.
[Aspect A]
A developing unit such as a developing unit 50 that develops a latent image on a latent image carrier such as the photoreceptor 1 and a stirring unit 51 that is disposed outside the developing unit and contains a part of the developer to stir the developer. In the developing device such as the developing device 5, the developing unit 5 includes a developer unit such as a circulation path 56 and an air pump 54 that transports the developer stirred in the stirring unit to the developing unit using air pressure. The developing unit includes a developer carrying member such as a developing roller 65 that can carry and rotate the developer on the surface, and a supply conveyance path 68 that supplies the developer conveyed from the developer conveying unit to the developer carrying member. And a developer inlet such as a developer inlet 82 into which the developer conveyed from the developer conveyor flows, and a communication port such as a communication port 83 communicating with the stirring unit, An exhaust part such as an exhaust part 84 for discharging air out of the apparatus. An air treatment having an inner wall surface such as a cylindrical inner wall surface 80a having a supply port such as a supply port 85 for supplying a developer such as developer G flowing in from the developer inflow port to the supply transport path at the bottom. An air processing chamber such as the chamber 80, the developer inflow port and the communication port being provided in contact with the peripheral surface of the inner wall surface from the tangential direction, and the exhaust unit being a developer inflow port. In addition, the supply port of the air processing chamber communicated with the upper portion of the supply conveyance path.

  According to this aspect A, as described in the above-described embodiment, the developer that rotates along the inner wall surface of the air processing chamber can flow, whereby the scattering and flying of the developer can be suppressed. On the other hand, since the air is exhausted upward while rotating, the separation between the two becomes high. Thereby, scattering of the developer to the exhaust part provided in the upper part of the air processing chamber can be suppressed, and an increase in internal pressure in the developing device can be suppressed over a long period of time.

[Aspect B]
In the aspect A, the exhaust part such as the exhaust part 84 includes a filter member such as a filter 84a that allows only air to pass through.
According to this aspect B, as described in the above embodiment, an increase in internal pressure in the developing device due to clogging of the filter member can be suppressed over a long period of time.

[Aspect C]
In [Aspect A] or [Aspect B], the cylindrical inner wall surface such as the inner wall surface 80a has a developer inlet such as the developer inlet 82 and a communication port such as the communication port 83 at a lower portion than the supply port 85 and the like. It has an inverted conical shape with a diameter that decreases toward the supply port.
According to this [Aspect C], as described in the above embodiment, the developer does not fall from the inner wall surface of the air processing chamber, and the developer flows down so as to slide along the inner wall surface. Can be more reliably suppressed.

[Aspect D]
In [Aspect A], [Aspect B] or [Aspect C], a developer inlet such as a developer inlet 82 provided in an air processing chamber such as the air processing chamber 80 and a communication port such as a communication port 83 are It is inclined downward from the horizontal and opens on an inner wall surface such as the inner wall surface 80a.
According to this [Aspect D], it becomes easier for the developer to flow along the inner wall surface, and scattering and flying of the developer can be suppressed more reliably.

[Aspect E]
In any one of [Aspect A] to [Aspect D], a developer inlet such as a developer inlet 82 provided in an air processing chamber such as the air processing chamber 80 and a communication port such as a communication port 83 are provided. The communication port is disposed immediately above the developer inlet.
According to this [Embodiment E], the developer in the air exhausted from the stirring unit is taken into the developer flowing in from the developer inflow port, so that the scattering and flying of the developer can be more reliably suppressed. .

[Aspect F]
An image forming apparatus including a developing device such as the developing device 5 according to any one of [Aspect A] to [Aspect E].
According to this [Aspect F], an image forming apparatus that exhibits the effect of the developing device according to any one of Aspects A to E, that is, an image forming apparatus that can maintain image quality over a long period of time is realized and provided. be able to.

  Although the present invention has been described with respect to specific embodiments and modifications, the technical contents disclosed by the present invention are not limited to those exemplified in the above-described embodiments and the like, and are configured by appropriately combining them. May be. It will be apparent to those skilled in the art that various embodiments, modifications, and examples can be made within the scope of the present invention in accordance with the necessity and application thereof.

In the above-described embodiment, the tandem color image forming apparatus that transfers the image to the endless belt-shaped intermediate transfer member and then transfers it to the sheet-like recording medium is described as an example. However, the present invention is not limited to this. The present invention can be similarly applied to a direct transfer type tandem color image forming apparatus in which a sheet-like recording medium is transferred and superposed while being conveyed by an endless belt.
Of course, the developing device of the present invention can also be applied to an electrophotographic image forming apparatus having a single image carrier or latent image carrier.

1 Photoconductor (an example of a latent image carrier / image carrier)
DESCRIPTION OF SYMBOLS 5 Developing apparatus 6 Image forming part 50 Developing part 51 Stirring part 52 Toner cartridge 53 Rotary feeder 54 Air pump (an example of a developer conveyance part, an air supply source)
55 Circulation path 56 Circulation path (an example of a developer transport unit)
60 motor (stirring drive source)
61 Motor (rotary feeder drive source)
65 Development roller (an example of a developer carrier)
68 Supply conveyance path 80 Air processing chamber 80a Inner wall surface of air processing chamber 81 Communication path 82 Developer inlet 83 Communication port 84 Exhaust part 84a Filter (an example of filter member)
85 Supply port 100 Device body G Developer P Transfer paper (an example of a recording medium)

Japanese Patent No. 2008-003561 JP 2009-036926 A

Claims (6)

A developing unit that develops the latent image on the latent image carrier, a stirring unit that is disposed outside the developing unit and that contains a part of the developer and stirs the developer, and the development stirred by the stirring unit In a developing device comprising a developer transport unit that transports the agent to the developing unit using air pressure,
The developing unit includes a developer carrying member that can rotate while carrying a developer on the surface, and a supply conveyance path that supplies the developer conveyed from the developer conveying unit to the developer carrying member. ,
A developer inflow port through which the developer conveyed from the developer conveying unit flows, a communication port communicating with the agitation unit, and an exhaust unit for discharging air out of the apparatus; An air processing chamber having a cylindrical inner wall surface having a supply port at the bottom for supplying the developer that has flowed into the supply conveyance path;
In the air processing chamber, the developer inlet and the communication port are provided so as to contact the peripheral surface of the inner wall surface from a tangential direction, and the exhaust portion includes the developer inlet and the communication port. Than the upper,
A developing device characterized in that the supply port of the air processing chamber is communicated with an upper portion of the supply conveyance path. The developing device according to claim 1,
The developing device, wherein the exhaust unit includes a filter member that allows only air to pass therethrough. The developing device according to claim 1 or 2,
The developing device according to claim 1, wherein the cylindrical inner wall surface has an inverted conical shape in which a diameter is narrower toward a supply port at a lower part than the developer inlet and the communication port. The developing device according to claim 1, 2 or 3,
The developing device, wherein the developer inlet and the communication port provided in the air processing chamber are inclined downward from the horizontal and open to the inner wall surface. The developing device according to any one of claims 1 to 4,
The developing device, wherein the developer inlet and the communication port provided in the air processing chamber are arranged immediately above the developer inlet.   An image forming apparatus comprising the developing device according to claim 1.

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