JP5407451B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

The present invention relates to a carrier for developing using a two-component developer comprising a toner and a carrier, a toner and a developer, a developing device using these developers, a process cartridge including the developing device, and an electrophotographic system. The present invention relates to an image forming apparatus such as a copying machine, a printer, a plotter, a facsimile, or a complex machine that uses these developing devices and / or process cartridges to form an image.
The present invention further relates to an image forming apparatus including a plurality of the developing devices or process cartridges and capable of color image formation.

  Conventionally, as a two-axis conveyance type developing device that performs development using a two-component developer, developer supply to a developer carrier (development sleeve) and developer conveyance member (screw, auger, etc.) and supply for collection It is composed of two developer transport members (screw, auger, etc.) and two transport paths, a collection transport path, a developer transport member (screw, auger, etc.) for transport and stirring after toner replenishment, and a stirring transport path. A structure in which these are arranged in a substantially horizontal direction below the developer carrier is known.

In recent years, there has been a demand for downsizing of an image forming apparatus, but as a conventional biaxial transport type developing device, the limit of downsizing has been reached. 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. Therefore, although the agitation function and the supply function are separated, two screws are essential because the developer must be circulated in the developing device for realization. That is, if there is only one screw, there is a problem that the developer is biased to one longitudinal side as a matter of course.
Further, when toner is replenished to the entire length of the developing sleeve, the need to move the developer largely by a screw is relatively less than when replenishing to one place in the longitudinal direction. In order to sufficiently stir the developer, there was a situation where a stirring paddle was essential in addition to one screw.

  For example, in consideration of this situation, in the configuration shown 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. The agitating in the horizontal direction is performed by combining the screws to be transported to. However, since a screw and a paddle must be provided separately, there is a drawback that the apparatus is increased in size. Moreover, the agent is conveyed in one of the longitudinal directions by the screw, and is conveyed in the direction opposite to the screw by the 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 agent is biased to the downstream side in the screw conveying direction. In order to solve this problem, if the screw conveyance capacity is reduced, the agent moves only in a very narrow region in the longitudinal direction, and thus density unevenness occurs when an image with a large difference in image area ratio is output in the longitudinal direction. There is a problem that causes it.

  Further, in a developing device represented by a conventional 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 stirred in the vicinity of the developing sleeve. There has been a problem that the carrier is 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, which complicates the configuration of the image forming apparatus using the developing device and reduces the operability during maintenance. there were.

For example, in consideration of such problems, an invention is known in which a developer optimization unit and a developer circulation conveyance unit are separately provided, and the development apparatus can be reduced in size and maintainability can be improved. For example, in Patent Document 2, a developer is transported and circulated between a developing unit and a 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 carrier is adjusted to optimize the developer 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 and the like, the apparatus can be miniaturized, the internal configuration of the complex image forming apparatus is simplified, and there is room for layout, facilitating maintenance.
However, when the developer is supplied to a simplified developing device using the developer optimizing means and the developer circulation / conveying means disclosed 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, there is a problem that a large density reduction occurs on the downstream side of the developer conveyance, and density deviation that cannot be ignored in the longitudinal direction occurs.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a small and sufficiently stirrable developing device and an image forming apparatus capable of reducing the density deviation in the longitudinal direction. It is in.

The features of the present invention, which is a means for solving the above problems, are listed below.
In the developing device of the present embodiment, a developer carrying body that conveys the developer, a regulating member that regulates the amount of developer on the developer carrying body facing the developer carrying body, and the developer carrying body In the developing device, comprising: a separating member for separating the developer from the first developer transporting means disposed in the vicinity of the developer carrying member and transporting the developer on one of the longitudinal sides; the example Bei the second developer conveying means and the developer conveying direction of the around the developer carrier first developer conveying means for conveying the developer in the same or opposite direction, before Symbol second The developer conveying means is provided on a side surface of the separating member on the developer carrier side , and the second developer conveying means is a skew plate, and the skew amount of the skew plate is it is greater than the skew plate spacing.
Further, the developing device of the present embodiment further includes third developer conveying means for conveying the developer in the same direction as the developer conveying direction in the first developer conveying means, and the third developer. The conveying means is a side surface of the separating member opposite to the developer carrying member.
In the developing device of the present embodiment, the restricting member is further provided above the developer carrier, and the third developer conveying means is a skew plate , and is disposed below the restricting member. It is characterized in that the developer falling on the substrate is conveyed in the longitudinal direction .
Further, the developing device of the present embodiment is further characterized in that the interval between the skew plates in the second developer conveying means is closer than the interval between the skew plates in the third developer conveying means.
In the developing device of the present embodiment, the skew feeding amount of the skew plate in the second developer transport unit is further made smaller than the skew feeding amount of the skew plate in the third developer transport unit. Features.
Further, in the developing device of the present embodiment, further, the skew amount of skew plate in the third developer conveying means being larger than the skew plate spacing.
Further, in the developing device of the present embodiment, further, the developer discharge port for discharging the developer, the developer density detecting member of the developer discharge opening neighborhood provided from the developing device, the developer concentration detection It has a stirring unit that determines the amount of toner to be newly replenished based on a detection signal from the member, and stirs the developer discharged from the developing device and the toner to be replenished .

A process cartridge according to the present invention includes at least an image carrier that forms an electrostatic latent image and a developing device, and is a process cartridge that can be attached to and detached from the image forming device. It is characterized by using.
The process cartridge of the present invention comprises a mixture of an image carrier on which an electrostatic latent image is formed, a developing device that visualizes the electrostatic latent image, and toner and a carrier. In the image forming apparatus provided with a developer transfer means for transferring the developer used for developing the toner to the developing device, any one of the developing devices described above is used.

  The present invention, which is a means for solving the above problems, has the following specific effects.

1 is a schematic configuration diagram illustrating a main part of an image forming apparatus according to an embodiment to which a developing device according to the present invention is applied. 1 is a schematic diagram illustrating a configuration of a developing device according to an embodiment of the present invention. It is a perspective view which shows schematic structure of the separator with which the skew feeding board is arrange | positioned. It is a top view which shows schematic structure of the separator from the 2nd skew board side. It is a top view which shows schematic structure of the separator from the 1st skew board side. It is a perspective view which shows schematic structure of the separator by which the skew board from which a space | interval differs is arrange | positioned. It is the schematic which shows the presence state of the developer on the separator in which the skew feeding board is arrange | positioned. FIG. 6 is a schematic diagram illustrating a developer conveyance state on a separator in which a skew plate having a skew amount smaller than a skew plate interval is disposed. FIG. 6 is a schematic diagram illustrating a developer conveyance state on a separator in which a skew plate having a skew amount larger than a skew plate interval is disposed. It is a schematic block diagram which shows the principal part of the image forming apparatus used as other embodiment with which the developing device which concerns on embodiment of this invention is applied. It is a schematic block diagram which shows the structure of the developing agent replenishment system in the developing device which concerns on embodiment of this invention, and a transfer system. It is a schematic block diagram which shows the structure of the image development part in the image development apparatus concerning embodiment of this invention. It is a schematic block diagram which shows the structure of the stirring part in the image development apparatus concerning embodiment of this invention. It is a schematic diagram showing the flow of the developer at the time of stirring in the stirring unit. It is a schematic block diagram which shows the structure of the rotary feeder part in the image development apparatus concerning embodiment of this invention. FIG. 2 is a schematic configuration diagram of a part of a developing device 40 according to the present embodiment.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(Embodiment 1)
Hereinafter, an embodiment in which the present invention is applied to an electrophotographic image forming apparatus will be described.
First, a basic configuration of the image forming apparatus according to the first embodiment will be described. FIG. 1 is a schematic configuration diagram illustrating a main part of the image forming apparatus. The image forming apparatus includes a document reading unit 4, an automatic document transport unit 2, an image forming unit 6, and a paper feeding unit 7.

The automatic document feeder 2 automatically supplies a document (not shown) placed on the upper surface thereof onto a contact glass 403 described later.
The document reading unit 4 is for reading an image of a document (not shown). When a start switch (not shown) is operated while a document is placed on a contact glass 403 fixed on the top of the document reading unit 4 by a user's manual operation, the document reading unit 4 immediately starts reading the document. Is done. Further, when the start switch is operated with the document placed on the automatic document feeder 5, the document is automatically fed onto the contact glass 403 and then the document reading by the document reading unit 4 is started. . When the reading is started, the document placed on the contact glass 403 is illuminated with a light source 404 that moves in the right direction in the drawing. The reflected light image from the document is sequentially reflected by the first mirror 406, the second and third mirrors 408. Then, after passing through the imaging lens 409, it is detected by the image sensor 410 comprising a CCD or the like for reading the reflected light image, and the image information is read.

The image forming unit 6 is for forming a toner image as an image on a transfer sheet, which is a recording medium 9 as a recording member, and includes an exposure device 80 and a photosensitive member 3 as a drum-shaped latent image carrier. Yes. Further, around the photosensitive member 3, a charging device 10, a developing device 40 as a developing unit, a transfer conveyance device 50, a photosensitive member cleaning device 20, a static eliminating device 18, and the like are provided. Further, a fixing device 70, a reverse paper discharge device 68, a registration roller pair 63, and the like are also provided. When the start switch is operated, rotation of the photosensitive member 3 is started by driving means (not shown).
The exposure device 80 optically modulates the laser light L based on the image signal read by the document reading unit 4 and exposes the photosensitive member 3. Specifically, the laser light L is emitted from the exposure light source 20 made of a laser diode or the like. The laser beam L is deflected in the main scanning direction (axial direction of the photosensitive member 3) on the rotary polygon mirror 22 that is rotationally driven by the polygon motor 21, and the scanning imaging lens system 23 including an fθ lens or the like. Pass through. Then, the light passes through the mirror 24 and the lens 25 and reaches the rotationally driven photoconductor 3 to scan the surface of the electrostatic latent image.

  The transfer conveyance device 50 abuts on the peripheral surface of the photosensitive member 3 to form a transfer nip while the transfer conveyance belt is endlessly moved while being tensioned by a plurality of tension rollers. Further, a transfer bias roller (not shown) is brought into contact with the back surface (the inner peripheral surface of the hoop) of the transfer conveyance belt in the transfer nip. A transfer bias is applied to the transfer bias roller by a power source (not shown), and a transfer electric field is formed in the transfer nip by this application.

  The electrostatic latent image formed on the photoreceptor 3 by exposure by the exposure device 80 is developed by the developing device 40 to become a toner image, and then enters the transfer nip. On the other hand, the registration roller pair 63 sandwiches a transfer sheet 9 sent from a sheet feeding unit 7 (described later) between the rollers based on the operation of the start switch. Then, the transfer paper 9 is sent out at a timing at which the transfer paper 9 can be superimposed on the toner image on the photoreceptor 3 at the transfer nip. By this feeding, the toner image on the photoreceptor 3 is brought into close contact with the transfer paper 9 at the transfer nip. Then, under the influence of the transfer electric field and nip pressure, the image is transferred from the surface of the photoreceptor 3 to the transfer paper surface. The transfer paper 9 that has passed through the transfer nip is fed into the fixing device 70 by the transfer conveyance belt of the transfer conveyance device 50. The fixing device 70 sandwiches the transferred transfer paper 9 between the heating roller 71 and the pressure roller 72. The toner image is discharged toward the reverse discharge device 68 while being fixed on the transfer paper 9 by the influence of heat and pressure.

  The reverse paper discharge device 68 passes the transferred transfer paper 9 through a discharge path and discharges it to a paper discharge tray (not shown) outside the apparatus. However, when the double-sided copy mode is selected by the user, the transfer sheet 9 is reversed through the reversing unit 69 and then conveyed toward the registration roller pair 63. As a result, the transfer paper 9 is sent again from the registration roller pair 63 toward the transfer nip, and a new toner image is transferred to the surface opposite to the surface on which the toner image has been transferred.

  The photoconductor cleaning device 20 cleans the transfer residual toner adhering to the surface of the photoconductor 3 after passing through the transfer nip, and accommodates it in a waste toner tank 92 that is a toner recovery unit. The surface of the photoreceptor 3 after cleaning is discharged by the discharging device 18 and then uniformly charged by the charging device 10 to prepare for the next image formation.

  The paper feed unit 7 includes three paper feed cassettes 61 a, 61 b, 61 c arranged in multiple stages, and each stores a plurality of transfer papers 9. A paper feed path having a plurality of pairs of transport rollers 64 is also provided. The paper feed cassettes 61a, 61b, 61c press the paper feed rollers 62a, 62b, 62c against the uppermost paper of the transfer paper 9 accommodated therein, and the uppermost paper is directed toward the paper feed path by its rotational drive. Send it out. When the start switch is operated, the transfer paper is sent out from any one of the paper feed cassettes to the paper feed path. The paper feed path 33 feeds the received transfer paper 9 toward the registration roller pair 63 of the image forming unit 6 by a plurality of pairs of transport rollers 64.

Next, the developing device 40 as a developing unit will be described.
FIG. 2 is a schematic diagram showing the configuration of the developing device according to the embodiment of the present invention.
A developing device 40 disposed on the side of the photoreceptor 3 and a two-component developer composed of a magnetic carrier and toner are used. During the developing operation, a two-component developer (hereinafter simply referred to as a developer) in which toner and a magnetic carrier are mixed is accommodated therein. This developer is a two-component developer comprising a toner having a particle size of 3 to 10 [μm] (volume average particle size) and a carrier having a particle size of 15 to 60 [μm] (average particle size, microtrack). It is. The toner concentration varies depending on the selection of each size, but can be used up to about 3.5 to 10%. The developing device 40 has a toner particle diameter of 7 [μm], a carrier particle diameter of 35 [μm], and a toner concentration of 7 [%].
Further, the developing device 40 includes a developing roller 43 that is a developer carrying member, and a conveying screw 41 that is a first developer conveying unit that supplies the developer to the developing roller 43 while conveying the developer . The amount of the developer carried on the surface of the developing roller 43 is regulated by a doctor blade 44 as a developer carrying amount regulating means, and is conveyed to a developing area which is a facing portion between the developing roller 43 and the photoreceptor 3. . The latent image on the surface of the photosensitive member 3 is developed in the development area, and the developer that has consumed the toner is separated from the development roller 43 at a portion where the development roller 43 and the conveying screw 41 face each other, and is collected as a collected developer. . The developing device 40 includes a toner concentration sensor 46 that detects the toner concentration of the collected developer near the downstream end of the conveyance screw 41 in the conveyance direction.
Further details will be described later.

The developer in the developing device 40 is transported by its own weight and includes a toner hopper 47 provided for stirring the developer. The toner hopper 47 that contains toner to be replenished to the developing device 40 has an opening 471 extending in the longitudinal direction formed in a side wall portion that divides the inside of the developing portion and the inside of the toner hopper 47. , And is covered with Mylar as a flexible member having a plurality of small holes 472 (φ0.9) for discharging toner. Further, as shown in FIG. 2, an agitator 473 for agitating the toner and replenishing the toner into the developing portion through the small hole 472 is disposed in the toner hopper portion 47. A mylar 474 is fixed to the tip of the agitator 473 by, for example, a double-sided tape. The length of the tip mylar 474 is set so that the tip is in contact with the inner wall of the toner hopper 47 and is bent, and the mylar surface having the small hole 472 can be rubbed.
In the toner hopper 47 described above, when the agitator 473 rotates and passes through the Mylar surface while sliding, the toner in the toner hopper 47 is pushed out from the small hole 472 to the inside of the developing unit and replenished. The replenished toner is pumped up to the developing roller 43 by the conveying screw 41 while being agitated with the developer.

In the developing device 40 of this embodiment, a toner concentration sensor 46 for detecting the toner concentration of the developer is disposed below the conveying screw 41. The detection signal of the sensor 46 is input to control composed of a microprocessor (not shown). Then, the control unit 16 compares the signal from the toner density sensor 46 with a predetermined set value, and when a deviation occurs, the control unit 16 replenishes the developing unit with an amount of toner that should be replenished. The agitator 473 is driven to rotate. More specifically, the toner density sensor 46 is calculated to determine the rotation speed of a motor (not shown), and power having a frequency corresponding to the rotation speed is supplied. Here, the amount of toner to be replenished varies depending on the total amount of carrier in the developer, the rotation speed of the developing roller 43, the average amount of toner consumed per image formation, and so on, and is obtained in advance by experiments. .
In the developing device 40 of the present embodiment, the rotational speed of the agitator 473 in the toner hopper 47 is controlled. Instead, one toner replenishment operation time is changed to perform one toner replenishment. The rotational speed of the agitator 473 per operation may be controlled.

Further, the developing device 40 of the present embodiment is provided with a separating member (hereinafter referred to as “separator”) 45 so as to face the surface of the developing roller 43 at a position below the doctor blade 44.
Further, in the developing device 40 of the present embodiment, as shown in FIG. 2, the developing roller 43, the doctor blade 44 that faces the developing roller 43 and regulates the amount of developer on the developing roller 43, and the developing roller A separator 45 that separates the developer from 43 and a first developer conveying means (hereinafter simply referred to as “conveying screw”) 41 that is disposed in the vicinity of the developing roller 43 and conveys the developer to one of the longitudinal sides. I have. There is provided a second developer conveying means (hereinafter simply referred to as “first skew plate”) 421 for conveying the developer in the direction opposite to the developer conveying direction of the conveying member around the developing roller 43. The first first skew plate 421 is on the side surface of the separator 45 on the developing roller 43 side. Therefore, the developer around the doctor blade 44 can be quickly supplied to the separator 45 and efficiently conveyed in the longitudinal direction.
Conventionally, the developer is transported in one longitudinal direction by a screw, and transported in the opposite direction to the screw by a skew plate 45. In addition, there is a paddle to stir the developer. Here, in order to reduce the size of the developing device 40, when the agitation paddle and the conveying screw are integrated to reduce the size, in the conventional configuration, with respect to the longitudinal conveying ability of the screw, the screw is moved in the direction opposite to the screw. The conveyance capability is small, and the developer is biased to the downstream side in the conveyance direction of the screw. For this reason, if the conveying ability of the screw is lowered, the developer moves only in a very narrow region in the longitudinal direction, which causes density unevenness when an image having a large difference in image area ratio in the longitudinal direction is output. .
Therefore, in the developing device 40 of this embodiment, by providing the first first skew plate 421, the developer around the doctor blade 44 can be quickly supplied to the separator 45 and efficiently conveyed in the longitudinal direction. Can do. In particular, since the side surface of the separator 45 on the side of the developing roller 43 is configured in accordance with the shape of the developing roller 43, the transport screw 41 is transported when the developer supplied from the agitator 47 is transported to the vicinity of the doctor blade 44. It is possible to easily transport in the direction opposite to the transport direction.

The developing device 40 according to the present embodiment includes a second developer transport unit and a third developer transport unit that transport the developer in a direction opposite to the developer transport direction in the transport screw 41, and the second developer. The first skew plate 421 serving as a transport unit is a side surface of the separator 45 on the developing roller 43 side, and the second skew plate 422 serving as a third developer transport unit is a side surface opposite to the developing roller 43 of the separator 45. It is.
By moving the developer in the longitudinal direction also on the side opposite to the developing roller 43 of the separator 45, the developer can be moved efficiently in the longitudinal direction without providing extra space, and the left-right density deviation is reduced. can do.
The first skew plate 421 is provided on the side surface of the separator 45 on the developing roller 43 side, and the second skew plate 422 is provided on the side surface of the separator 45 on the side opposite to the developing roller 43, thereby moving the screw in the direction of screw conveyance. In the case where the transfer is insufficient, efficient transfer can be performed and the left-right density deviation can be reduced.

FIG. 3 is a perspective view showing a schematic configuration of a separator on which a skew plate is arranged.
FIG. 4 is a plan view showing a schematic configuration of the separator from the second skew plate side.
FIG. 5 is a plan view showing a schematic configuration of the separator from the first skew plate side.
As shown in FIGS. 3, 4, and 5, the separator 45 is attached with a first skew plate 421 and a second skew plate 422.
3 shows the separator 45, the first skew plate 421, and the second skew plate 422. FIG. 4 shows the separator 45 and the second skew plate 422 observed from the side opposite to the developing roller 43. The flow of the developer spilling from the vicinity of the doctor blade 44 is shown. FIG. 5 shows the separator 45 and the first skew plate 421 observed from the side opposite to the developing roller 43, and the doctor blade 44 from the vicinity of the conveying screw 41. The flow of the developer pumped up along the developing roller 43 to the vicinity is shown. The first skew plate 421 and the second skew plate 422 are configured to skew the developer flowing along the separator 45 in a direction perpendicular to the axial direction of the developing roller 43.
In particular, in the developing device 40 of the present embodiment, the doctor blade 44 exists above the developing roller 43, and the second skew plate 422 conveys the developer that falls downward from the doctor blade 44 in the longitudinal direction. The developer can be efficiently conveyed, and the left-right density deviation can be reduced.
By providing the first skew plate 421 and the second skew plate 422 in the developer transport path, it is possible to promote the transport of the developer in the longitudinal direction and reduce the left-right density deviation.

Further, in the developing device 40 of this embodiment, the interval between the first skew plates 421 is made closer than the interval between the second skew plates 422. The developer can be efficiently conveyed, and the left-right density deviation can be reduced.
This is because the closer the slanting plate 42 is, the more the flow of the developer is inhibited. For this reason, it is necessary to make it sparse to some extent, but if it is made too sparse, the developer amount may be biased in the longitudinal direction. That is, the skew plate 42 creates a portion where a large amount of developer is supplied and a portion where a small amount of developer is supplied. Immediately before the doctor blade 44, if the deviation of the developer amount in the longitudinal direction becomes large, a pumping amount deviation is generated, which causes vertical streaks in the image. Therefore, in the first skew plate 421 immediately before the doctor blade 44, the skew plate 42 is spaced at a sparse interval so that the agent can be efficiently transported, and at a close interval such that the pumping amount deviation does not occur. Must be installed. On the other hand, when the developer spilled from the doctor blade 44 is transported, even if there is a deviation in the longitudinal direction, the pumping amount deviation is not caused. Therefore, it is desirable that the second skew plate 422 be installed at a sparser distance than the first skew plate 421 so as not to hinder the flow of the developer.

In the developing device 40 of this embodiment, the skew amount of the skew plate 42 in the first skew plate 421 is made smaller than the skew amount of the skew plate 42 in the second skew plate 422. Here, the skew amount can be defined by the symbol B in FIG. The skew amount is a distance in the longitudinal direction of the skew plate itself that changes in the longitudinal direction. By this, efficiently developer can carry, it is possible to reduce the lateral density deviation.
The amount of skew can be changed by changing the angle of the skew plate 42 (skew angle). The larger the skew angle of the skew plate 42, the greater the agent transport capability in the longitudinal direction, but the more obstructing the developer flow. Accordingly, it is desirable that the skew angle be as large as possible within a range that does not hinder the flow of the developer. Here, in the first skew plate 421, the developer must be pumped up against the gravity near the doctor blade 44, whereas in the second skew plate 422, the developer is skewed when the developer is dropped by gravity. I am letting. Therefore, when the first skew plate 421 and the second skew plate 422 have the same skew angle, the developer flow in the first skew plate 421 is worse than that of the second skew plate 422. Further, since the agent pumped up by the first skew plate 421 is divided into one supplied to the developing roller 43 and one conveyed by the second skew plate 422, it is supplied to the second skew plate 422 per unit time. Since the amount of the agent to be applied is smaller than the amount supplied to the first skew plate 421, the agent must flow more smoothly on the first skew plate 421 than on the second skew plate 422. Therefore, by making the skew angle of the first skew plate 421 smaller than the skew angle of the second skew plate 422, the agent flows smoothly on the first skew plate 421, and on the second skew plate 422, It can be conveyed in the longitudinal direction.

Further, in the developing device 40 of the present embodiment, the skew amount of the skew plate 42 is set larger than the skew plate interval. As a result, the developer can be efficiently conveyed, and the left-right density deviation can be reduced.
FIG. 6 is a perspective view showing a schematic configuration of a separator in which skew plates having different intervals are arranged.
FIG. 7 is a schematic diagram showing the presence state of the developer on the separator on which the skew plate is arranged.
FIG. 8 is a schematic diagram illustrating a developer conveyance state on a separator on which a skew plate having a skew amount smaller than a skew plate interval is disposed.
FIG. 9 is a schematic diagram illustrating a developer conveyance state on a separator on which a skew plate having a skew amount larger than a skew plate interval is disposed.
This is because when the skew amount of the skew plate 42 (B in FIG. 6) is smaller than the skew plate interval (A in FIG. 6), the developer (in the skew direction downstream side in the vicinity of the skew plate 42) ( 8C is skewed and transported in the longitudinal direction, but the developer (D in FIG. 8) on the upstream side in the skew direction near the skew plate may not be transported at all in the longitudinal direction. In this case, as shown in FIG. 7, along the skew plate 42, the developer is divided into a portion where the developer is present and a portion where the developer is not present.
By making the skew amount of the skew plate 42 larger than the skew plate interval, the developer on the upstream side in the skew direction near the skew plate is also conveyed in the longitudinal direction as shown in FIG. 9D.

  In the developing device 40 of the present embodiment described above, the two-component developer accumulated in the inner bottom portion of the developing device 40 is agitated by the rotation of the conveying screw 41, and the developer is removed from the near side to the far side in FIG. While being conveyed, it is pumped up and supplied to the developing roller 43. The developer pumped up by the developing roller 43 is held on the surface of the developing roller 43 by the magnetic force of the developing roller 43 and is conveyed to the vicinity of the doctor blade 44 as the developing roller 43 rotates. When the developer is transported along the developing roller 43 from the vicinity of the transport screw 41 to the vicinity of the doctor blade 44, the first skew plate 421 is skewed with respect to the direction orthogonal to the axial direction of the developing roller 43. It is conveyed to the vicinity of the doctor blade 44. The transport direction by the skew plate is from the back side to the front side in FIG. 8 and is opposite to the transport direction of the transport screw 41. The skew amount of the first skew plate 421 is 4.5 mm, and the interval between the skew plates 42 is 4.0 mm. The relationship between the amount of skew and the interval between the skew plates 42 in FIGS. 3 and 5 is different from the above-described interval in order to make the arrangement easy to see. FIG. 5 shows the state of conveyance of the developer at this time by arrows. The developer supplied to the developing roller 43 by the conveying screw 41 and conveyed to the portion facing the photosensitive member 3 by the rotation of the developing roller 43 is scraped off by the doctor blade 44 to a certain amount. The developer is supplied to the surface of the photoreceptor 3 and used for developing the electrostatic latent image.

  On the other hand, the developer scraped off by the doctor blade 44 flows on the separator 45. The fluid developer flows down onto the conveying screw 41 while being skewed with respect to the direction orthogonal to the axial direction of the developing roller 43 by the second skew plate 422, thereby causing so-called lateral stirring (developing roller axial direction). Done. The conveyance direction by the skew plate is from the back side to the front side in FIG. 2, and is opposite to the conveyance direction of the conveyance screw 41. The skew amount of the second skew plate 422 is 20 mm, and the skew plate interval is 18 mm. The relationship between the skew amount and the skew plate interval in FIGS. 3 and 4 is different from the above interval in order to make the arrangement easy to see. FIG. 4 shows the state of the developer dropping at this time by arrows. The developer dropped on the transport screw 41 is stirred by the transport screw 41 and then pumped up to the developing roller 43. The above is repeated.

Next, an image forming operation in this embodiment will be described. A description will be given based on the overall view of the image forming apparatus 1 shown in FIG. In this embodiment, a voltage is applied to the charging roller 11 to uniformly charge the photosensitive member 3, and a latent image is formed on the photosensitive member 3 by the exposure device 80 using an LD. The charging roller 11 may be contaminated with toner that has passed through the cleaning blade 21, but contaminants are removed by the cleaning roller 12 that contacts the charging roller 11, and the charging roller 11 is kept uncontaminated, The photoreceptor 3 can be uniformly charged without worrying about toner contamination.
The developing device 40 is charged and exposed by a known electrophotographic image forming process, and a visible image is formed on the photosensitive member 3 on which an electrostatic latent image is formed by a known dry two-component developing method using a magnetic brush developing method. Form. The visible image formed on the photosensitive member 3 is transferred to paper at the nip portion with the transfer roller 52. The residual toner remaining on the photoconductor 3 after the transfer is removed from the photoconductor 3 by the cleaning device 20 to prepare for the next image formation. The cleaning device 20 includes a cleaning blade 21 and a waste toner conveying screw 22, and the transfer residual toner on the photosensitive member 3 is scraped off by the cleaning blade 21. The scraped transfer residual toner is transferred to the waste toner tank 92 by the waste toner conveying screw 22. Carried.
The transfer paper 9 is conveyed one by one from the paper supply device 60 by the paper supply roller 62 and is conveyed to the registration roller 63 along the paper conveyance guide. The resist image is conveyed from the registration roller 63 to the transfer portion, and the visible image formed on the photoconductor 3 is transferred to the transfer paper 9 at the transfer portion. The transfer paper 9 is transported to the fixing device 70 by the paper transport belt 56, and the toner image is fixed and discharged to the paper discharge tray. The fixing device 70 includes a fixing roller 71 and a pressure roller 72, and fixes the toner image on the transfer paper 9 by applying heat and pressure.

As described above, the developing device 40 according to the present embodiment is integrally supported with the photosensitive member 3 to form the process cartridge 2, so that it can be handled in a small size and easily.
Furthermore, since the developing device 40 and the process cartridge 2 are applied to the image forming apparatus 1, the developing device 40 and the like can be reduced in size. Accordingly, the size of the image forming apparatus 1 that is detachable can be reduced accordingly. Can be handled easily.

(Embodiment 2)
First, an outline of the configuration of the image forming apparatus 1 including the developing device 40 according to the present embodiment will be described based on FIG. FIG. 10 is a schematic configuration diagram showing a main part of an image forming apparatus according to another embodiment to which the developing device according to the present invention is applied.
The image forming apparatus 1 of the present embodiment based on FIG. 10 is based on FIG. 1, but is different from the image forming apparatus 1 in the image forming operation. Here, a color image can be obtained by superimposing toner images having a plurality of colors on the intermediate transfer belt 51.
Therefore, the process cartridges 2Y, 2M, and the image forming units corresponding to the respective colors (yellow, magenta, cyan, black) are opposed to the lower surface of the intermediate transfer belt 51 as an unfixed image carrier in the transfer conveyance device 50. 2C and 2K are juxtaposed. These process cartridges 2Y, 2M, 2C, and 2K have the same structure except that the color of the toner used in the image forming process is different. Each of the process cartridges 2Y, 2M, 2C, and 2K includes a photosensitive member 3 as a latent image carrier, a charging device 10, a developing device 40, a cleaning device 20, and the like disposed around the photosensitive member 3. .

An image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photoreceptor 3, and a desired toner image is formed on the photoreceptor 3. The photosensitive member 3 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 of the charging device 10 (charging process).
Thereafter, the surface of the photoreceptor 3 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 photoreceptor 3 reaches a position facing the developing device 40, and the electrostatic latent image is developed at this position to form a desired toner image (developing process).
Thereafter, the surface of the photoreceptor 3 reaches a position facing the intermediate transfer belt 51 and the primary transfer bias roller 52, and the toner image on the photoreceptor 3 is transferred onto the intermediate transfer belt 51 at this position (1). Next transfer process).
Thereafter, the surface of the photoreceptor 1 reaches a position facing the cleaning device 20, and untransferred toner remaining on the photoreceptor 3 is collected at this position (cleaning step). After cleaning, the surface of the photoreceptor 3 is initialized with a potential by a static eliminating device (not shown). Thus, a series of image forming processes performed on the photoconductor 3 is completed.

  The above-described image forming process is performed by each of the four process cartridges 2Y, 2M, 2C, and 2K, as shown in FIG. That is, the laser beam based on the image information is directed from the exposure device 80 disposed below the process cartridges 2Y, 2M, 2C, and 2K onto the photoreceptors 3 of the process cartridges 2Y, 2M, 2C, and 2K. Irradiated. Thereafter, the toner images of the respective colors formed on the respective photoreceptors 3 through the developing process are transferred onto the intermediate transfer belt 51 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 51.

  The four primary transfer bias rollers 52Y, 52M, 52C, and 52K sandwich the intermediate transfer belt 51 between the photoreceptors 3Y, 3M, 3C, and 3K to form primary transfer nips. The primary transfer bias rollers 52Y, 52M, 52C, and 52K are applied with a transfer bias having a polarity opposite to the polarity of the toner. The intermediate transfer belt 51 sequentially passes through the primary transfer nips of the primary transfer bias rollers 52Y, 52M, 52C, and 52K. In this way, the toner images of the respective colors on the photoreceptors 3Y, 3M, 3C, and 3K are primarily transferred while being superimposed on the intermediate transfer belt 51.

Thereafter, the intermediate transfer belt 51 onto which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 54 as a secondary transfer unit. The color toner image formed on the intermediate transfer belt 51 is transferred onto a transfer sheet 9 as a recording medium conveyed to the secondary transfer nip position.
Thus, a series of transfer processes performed on the intermediate transfer belt 51 is completed. A paper feeding device 60 is arranged in the paper feeding unit 7 disposed in the lower part of the apparatus main body 1. A plurality of transfer papers 9 are stored in the paper feed cassette 61 and are separated one by one by a paper feed roller 62 and fed. The fed transfer paper 9 is temporarily stopped by the registration roller pair 63, and after the oblique deviation is corrected, it is conveyed toward the secondary transfer nip by the registration roller pair 63 at a predetermined timing. As described above, a desired color image is transferred onto the transfer paper 9 in the secondary transfer nip.

The transfer paper 9 onto which the color image has been transferred at the position of the secondary transfer nip is conveyed to the fixing device 70 where the color image transferred to the surface by the heat and pressure by the fixing roller 71 and the pressure roller 72 is transferred. It is fixed.
After the fixing, the transfer paper 9 is discharged as an output image to the paper discharge unit formed on the upper surface of the apparatus main body by the paper discharge roller pair 64 and stacked. Thus, a series of image forming processes in the image forming apparatus 1 is completed.

Next, the configuration of the developing device 40 as the developer agitation / circulation system will be described in detail.
Further, in the image forming apparatus 1 of the present embodiment, the developing device 40 includes a system for supplying a two-component developer outside the developing unit 250 where development is performed. The system for replenishing the two-component developer will be described in detail later. The stirring unit 251 as a mechanism for optimizing mixing and stirring of the developer, and the stirring unit 251 and the developing unit 250 are provided. It also has a mechanism for transferring the developer to be connected.
FIG. 11 is a schematic configuration diagram showing configurations of a developer supply system and a transfer system in the developing device according to the embodiment of the present invention.
Specifically, as illustrated in FIG. 11, the developing device 40 includes a developing unit 250 that develops the electrostatic latent image on the photoreceptor 3 and a developer (hereinafter simply referred to as “agent”) at a position away from the developing unit 250. Agitator 251 that performs agitation in accordance with the state), a toner storage container 110 for supplying toner to the agitator 251, a rotary feeder 253 provided below the agitator 251, An air pump 254 or the like as a developer circulation drive source to be conveyed at the same time.
The developing section 250 and the stirring section 251 are connected by a circulation path 255, and the rotary feeder 253 and the developing section 250 are connected by a circulation path 256. The toner container 252 and the agitation unit 251 are connected by a toner supply path 57, and the air pump 54 and the rotary feeder 253 are connected by a pipe line 58. Further, in FIG. 11, a motor 259 as a toner replenishing drive source, a motor 260 as an agitation drive source, and a motor 261 as a drive source of the rotary feeder 253 are provided.

FIG. 12 is a schematic configuration diagram showing the configuration of the developing unit in the developing device according to the embodiment of the present invention.
As shown in FIG. 12, the developing unit 250 includes a casing 401 that constitutes the developing unit, a conveyance screw 41 that is rotatably supported in the casing 401, and has spiral fins, and a developing roller 43. . A casing 401 contains a two-component developer in which toner and carrier are mixed. The developer is circulated and conveyed in the casing 401 by the conveying screw 41.
The developer is transported from the front side to the back side in the drawing by the transport screw 41, and a part of the developer is sucked and attracted by the magnetic force by the developing roller 43, and is evenly uniformed by the doctor blade 44. By contacting the body 3, the electrostatic latent image on the photoreceptor 3 is developed with toner to form a toner image.
The developed developer is separated in the vicinity of the stirring screw 41 and transferred from the discharge port 48 to the stirring unit 251 from the toner discharge path 267 of the mechanism for transferring the developer. Further, the toner is transferred from the agitation unit 251 to the receiving port 268 through the pipe 256 and supplied to the developing unit 250 from the supply port 47.

Further, as shown in FIG. 11, the developer after development is conveyed from the discharge port 48 formed at the end of the conveying screw 41 to the stirring unit 251 through the circulation path 255. A toner concentration detection sensor 46 (not shown) is installed on the most downstream side of the transport screw 41, and toner is supplied from the toner storage container 252 based on the signal. Toner supply is performed by rotating a screw (not shown) in the toner supply path 257 by the motor 259. The toner is replenished in the circulation path immediately before the entrance of the stirring unit 251.
In the stirring unit 251, the developer after development and the replenished toner are mixed to form a developer having an appropriate toner concentration and charge amount. The developer passes through the discharge port 270 formed in the lower part of the stirring unit 251 and enters the rotary feeder 253. Due to the rotation of the rotor 275 in the rotary feeder 253, the developer is quantitatively discharged downward, passes through the circulation path 256, and is supplied again to the developing unit 250 through the receiving port 268.

FIG. 13 is a schematic configuration diagram showing the configuration of the agitation unit in the developing device according to the embodiment of the present invention. A developer replenishing port 269 is provided on the upper surface of the stirring unit 251, and a discharge port 270 is provided on the lower surface. The stirrer body 251 a has an inverted conical shape whose diameter decreases toward the discharge port 270. ing.
A screw 271 that conveys the agent from the bottom to the top is provided in the center of the stirring unit main body 251a, and two rotatable stirring members 272 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 272 and the screw 271 are rotated by a motor 260. The screw 271 is directly connected to the motor 260, and the outer stirring member 272 rotates via the reduction gear trains 273a to 73d. The agitating member 272 is fixed obliquely with respect to the support portion 274 directly connected to the reduction gear train.
The conveyance from the supply port 269 to the discharge port 270 in the stirring unit 251 uses gravity. Since the developer is always present as a buffer in the stirring unit 251, the unmixed developer is not discharged as it is.
The rotary feeder 253 includes a rotor 275 that is rotated by a motor 261 and has a plurality of radially extending two blades 75 a, and a stator 276 that covers the rotor 275. The rotary feeder 253 is connected to the circulation path 256 and the pipe line 258 by a joint pipe line 277.

FIG. 14 is a schematic diagram illustrating the flow of the developer during stirring in the stirring unit.
The agent lifted upward in the direction of the arrow A by the rotation of the screw 271 moves in the direction of the arrow B along with the rotation of the stirring member 272 that rotates on the outside, and is gathered around the screw 271 again. As described above, the developer is constantly convected in the stirring unit 251. By this convection, the entire container (within the stirring portion main body 251a) 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 studies by the present inventors, it has been found that the contact probability is increased by convection of the developer in the stirring portion 251 and the damage to the developer is small.

Next, the rotary feeder unit will be described in detail.
FIG. 15 is a schematic configuration diagram illustrating a configuration of a rotary feeder unit in the developing device according to the embodiment of the present invention.
As shown in FIG. 15, the rotor 275 and the stator 276 of the rotary feeder 253 are provided with a clearance between the tip of the blade 275 a of the rotor 275 and the inner surface of the stator 276.
As described above, when there is a gap between the rotor 275 and the stator 276, a part of the air generated from the air pump 254 flows into the stirring unit 251 through this gap and sends the developer to the developing unit 250. 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 transport the developer discharged from the rotary feeder 253, it is preferable not to allow the air of the air pump 254 to flow into the stirring unit 251 as much as possible.

Therefore, in the present embodiment, a plate-like air inflow doctor that restricts the inflow of air to the rotary feeder 253 side between the discharge side of the rotary feeder 253 and the developer transfer path (here, in the joint pipe 277). A blade 280 was placed. Three air inflow doctor blades 280 are fixedly arranged at intervals in the air supply direction.
When the air sent from the air pump 254 reaches the inside of the joint pipe 277 as the mixing unit, the air transferred to the developing unit 250 together with the developer through the circulation path 256 and the reverse flow toward the upper rotary feeder 253 side. Although there is air, the air inflow doctor blade 280 regulates the flow of air, so that the air flowing back to the rotary feeder 253 side is reduced.
The air inflow doctor blade 280 is installed so that its upper end portion is inclined toward the air pump 254 side and the angle θ formed with the horizontal line is an acute angle, so that the air flow toward the rotary feeder 253 side is restricted. High effect. The developer discharged from the rotary feeder 253 falls between the air inflow doctor blade 280 and the inner surface of the joint pipe line 277 and between the air inflow doctor blade 280.
The number of air inflow doctor blades 280 may be one, but a plurality of air inflow doctor blades 280 has a higher air inflow restriction function.

Further, other embodiments to which the present invention is applied will be described below.
FIG. 16 is a schematic configuration diagram of a part of the developing device 40 according to the present embodiment.
In the developing device 40 of this embodiment, as is apparent from FIG. 16, in order to optimize the developer, the developer whose charge amount and toner concentration are adjusted is supplied from the developer supply port 49 to the developing unit 250. Then, after being used for development, it is collected from the developer discharge port 48 and sent to the agitation unit 251 to optimize the developer again. The developer supplied from the developer supply port 49 into the developing unit 250 is agitated by the rotation of the transport screw 41, and in FIG. 16, the developer is transported from the back side to the near side and pumped up to the developing roller 43. Supply.
In the developing unit 250 provided in the developing device 40 of this embodiment, a developing roller 43 provided with a magnet is rotatably supported so as to face the photoreceptor 3. The surface of the developing roller 43 and the surface of the photoreceptor 3 are opposed to each other with a predetermined interval maintained with strict tolerance accuracy. In the developing device 40 including the developing roller 43, a conveying screw 41 that is rotationally driven is provided at the bottom.

A doctor blade 44 is provided so as to face the surface of the developing roller 43 with a predetermined gap. A separator 45 is provided so as to face the surface of the developing roller 43 at a position below the doctor blade 44.
As shown in FIGS. 3, 4, and 5, first separators 421 and 422 are attached to the separator 45.
The developing device 40 according to the present invention includes a photosensitive member 3 on which an electrostatic latent image is formed, and a toner and a carrier mixed to visualize the electrostatic latent image. The main body of the image forming apparatus 1 is provided with a developer transfer means for transferring a powder developer used for developing the image to the developing section 250. The developing means includes a developing roller 43 and a developing roller 43. A doctor blade 44 that controls the amount of developer on the developing roller 43 oppositely, a separator 45 that separates the developer from the developing roller 43, and a first member that is disposed near the developing roller 43 and conveys the developer to one of the longitudinal sides. One developer conveying means (“conveying screw”) 41 and second developer conveying means (hereinafter referred to as “slanting”) that conveys the developer around the developing roller 43 in the same direction as the developer conveying direction of the conveying member. It is written as a row board.) The first Hasugyoban 421 is disposed on the side surface of the developing roller 43 side of the separator 45. In the developing device 40, the developer is transported in the longitudinal direction by using the transport screw 41 and the separator 45 in the longitudinal direction of the developer in the developing means. By conveying the developer in the longitudinal direction, the left-right density deviation can be reduced.
In the developing device 40 so far, the developer whose density has been adjusted is supplied to the developing sleeve 131. Therefore, the developing device itself can be reduced in size and maintenance is facilitated. However, there is a case where the developer used in the development and having the lowered developer concentration is pumped up again to the developing sleeve and causes a reduction in image density.

In particular, when the size is reduced and the amount of the agent in the vicinity of the developing sleeve becomes small, the developer is used for development several times without going through the stirrer 140 that is the density adjusting mechanism, causing an extreme decrease in image density. . This is because the developer feed amount and developer feed speed in the vicinity of the developing sleeve are insufficient. When there is a large amount of developer feed, when the agent used for development is pumped up again to the developing sleeve, there are many agents whose concentration has been adjusted nearby. Less. When the developer feeding speed is fast, a lot of developer whose density has been adjusted is supplied to the developer whose density has been lowered, and the developer whose density has been lowered is quickly carried to the stirrer 140. The influence of the developer causing the density decrease is reduced.
In the developing device 40 of this embodiment, the developer is fed in the same direction as the screw also on the side surface of the separator 45 on the developing roller 43 side, so that the developer feeding speed is increased and the left-right density deviation of the image is reduced. .

Further, in the developing device of the present embodiment, the first skew plate 421 as the second conveying unit that conveys the developer in the same direction as the developer conveying direction in the first developer conveying unit, the third developer The first skew plate 421 is a side surface of the separator 45 on the developing roller 43 side, and the second skew plate 422 is a side surface of the separator 45 opposite to the developing roller 43. is there.
By moving the developer in the longitudinal direction also on the side opposite to the developing roller 43 of the separator 45, the developer can be moved efficiently in the longitudinal direction without providing extra space, and the left-right density deviation is reduced. can do. The first skew plate 421 is provided on the side surface of the separator 45 on the developing roller 43 side, and the second skew plate 422 is provided on the side surface of the separator 45 on the side opposite to the developing roller 43, thereby moving the screw in the direction of screw conveyance. Therefore, efficient transport is possible when the transport is insufficient, and the left-right density deviation can be reduced.

Further, in the developing device 40 of the present embodiment, the doctor blade 44 exists above the developing roller 43, and the second skew plate 422 uses the skew plate 45 for the developer that falls downward from the doctor blade 44. Then transport in the longitudinal direction. The developer can be efficiently conveyed, and the left-right density deviation can be reduced. By providing the skew feeding plate 45 in the developer conveyance path, it is possible to promote conveyance of the developer in the longitudinal direction and to reduce the left-right density deviation.
Further, in the developing device 40 of this embodiment, the interval between the first skew plates 421 is made closer than the interval between the second skew plates 422. The developer can be efficiently conveyed, and the left-right density deviation can be reduced.
Further, in the developing device 40 of the present embodiment, the skew amount of the first skew plate 421 is made smaller than the skew amount of the second skew plate 422. Here, the skew amount is a distance in which the developer entering from the skew plate entrance moves in the longitudinal direction before coming out at the exit. As a result, the developer can be efficiently conveyed, and the left-right density deviation can be reduced.
In the developing device 40 of the present embodiment, the skew amount of the skew plate 45 is larger than the skew plate interval. As a result, the developer can be efficiently conveyed, and the left-right density deviation can be reduced.

  Further, the operation of the developing unit 250 including the first skew plates 421 and 422 will be described. 9 is a perspective view of the separator 45, the first skew plate 421, and the second skew plate 422, and FIG. 10 is a side view of the separator 45 and the second skew plate 422 opposite to the developing roller 43. FIG. 11 is a plan view observing the separator 45 and the first skew plate 421 from the side opposite to the developing roller 43, and a conveying screw. A flow of the developer pumped up along the developing roller 43 from the vicinity of 41 to the vicinity of the doctor blade 44 is shown. The first skew plate 421 and the second skew plate 422 are configured to skew the developer flowing along the separator 45 in a direction perpendicular to the axial direction of the developing roller 43.

  The developer pumped up by the developing roller 43 is held on the surface of the developing roller 43 by the magnetic force of the developing roller 43 and is conveyed to the vicinity of the doctor blade 44 as the developing roller 43 rotates. When the developer is transported along the developing roller 43 from the vicinity of the transport screw 41 to the vicinity of the doctor blade 44, the first skew plate 421 is skewed with respect to the direction orthogonal to the axial direction of the developing roller 43. It is conveyed to the vicinity of the doctor blade 44. The conveyance direction by the skew plate is from the back side to the front side in FIG. 1 and is the same direction as the conveyance direction of the conveyance screw 41. The skew amount of the first skew plate 421 is 4.5 mm, and the skew plate interval is 4.0 mm. The relationship between the skew amount and the skew interval in FIGS. 9 and 11 is different from the above interval in order to make the arrangement easy to see. FIG. 11 shows the state of conveyance of the developer at this time by arrows. The developer supplied to the developing roller 43 by the conveying screw 41 and conveyed to the portion facing the photosensitive member 3 by the rotation of the developing roller 43 is scraped off by the doctor blade 44 to a certain amount. The developer is supplied to the surface of the photoreceptor 3 and used for developing the electrostatic latent image. On the other hand, the developer scraped off by the doctor blade 44 flows on the separator 45. The fluid developer flows down onto the conveying screw 41 while being skewed with respect to the direction orthogonal to the axial direction of the developing roller 43 by the second skew plate 422, thereby causing so-called lateral stirring (developing roller axial direction). Done. The conveyance direction by the skew plate is from the back side to the front side in FIG. 1 and is the same direction as the conveyance direction of the conveyance screw 41. The skew amount of the second skew plate 422 is 20 mm, and the skew plate interval is 18 mm. The relationship between the skew amount and the skew plate interval in FIGS. 9 and 10 is different from the above interval in order to make the arrangement easy to see. FIG. 10 shows the state of the developer dropping at this time by arrows. The developer that has fallen onto the transport screw 41 is stirred by the transport screw 3 and then pumped up to the developing roller 43.

Thereafter, the above is repeated, and the developer that comes to the foremost side exits from the developer discharge port 47 shown in FIG. 22 and is carried to the stirring unit 251 that optimizes the developer.
In the developing device 40 of the present embodiment, a developer discharge port 48 for discharging the developer from the developing unit 250 and a toner concentration sensor 46 in the vicinity of the developer discharge port 48 are provided, and the vicinity of the developer discharge port 48 is provided. The amount of toner to be replenished to the developer discharged from the developing unit is determined based on the detection signal in the toner density sensor 46, and stirring for stirring the developer discharged from the developing unit and the newly replenished toner is performed. Part 251. Here, the toner density can be adjusted with high accuracy. By measuring the toner concentration discharged from the developing unit 250 and performing toner replenishment according to the detection result, the discharged toner can be set to an appropriate agent concentration.
In addition, although the amount of skew and the distance between the skew plates of the first skew plates 421 and 422 are partially shown as numerical values, of course, this is an example of the embodiment and does not limit the scope of the claims. By taking the configuration as described above, the agent can be transported more efficiently than when the agent is transported only by a screw. As a result, the agent having a lowered toner concentration can be quickly sent to the discharge port, and the density deviation in the longitudinal direction of the developing sleeve can be reduced.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Process cartridge 3 Image carrier / photosensitive body 4 Reading apparatus 402 Control board 403 Contact glass 404 Lamp 405 First traveling body 406 Mirror 407 Second traveling body 408 Mirror 409 Imaging lens 410 Reading sensor 5 Automatic document conveyance Equipment (ADF)
6 Image forming unit 7 Paper feeding unit 9 Recording member 10 Charging device 11 Charging roller 18 Static elimination device 20 Cleaning device 30 Lubricant coating device 40 Developing device 401 Casing 41 Transport screw 42 Skew plate 421 First skew plate 422 Second skew Row plate 43 Developing roller 44 Doctor blade 45 Separator 46 Toner density sensor 47 Toner hopper portion 471 Toner hopper opening portion 472 Small hole 473 Agitator 474 Mylar 48 Developer discharge port 49 Developer supply port 50 Transfer conveyance device 51 Intermediate transfer belt 52 Primary transfer roller 531, 532, 533, 534 Support roller 54 Secondary transfer roller 55 Intermediate transfer belt cleaning device 56 Conveyor belt 60 Paper feed device 61 Paper feed unit 62 Paper feed roller 63 Registration roller 64 Paper discharge roller 68 Reverse paper discharge device 6 Reversing unit 70 Fixing device 71 Heating roller 72 Pressure roller 80 Exposure device 90 Replenishment / storage device 91 Toner replenishment hopper 92 Waste toner tank 250 Developing unit 251 Stirring unit 251a Stirring unit body 252 Toner storage container 253 Rotary feeder 254 Air pumps 255, 256 Circulation path 259, 260, 261 Motor 256 Pipe line 268 Receiving port 269 Replenishing port 270 Discharging port 271 Screw 272 Stirring member 273 Reduction gear train 275 Rotor 275a Blade 276 Stator 277 Joint pipeline 280 Air inflow doctor blade

JP 08-041882 Japanese Patent No. 3733496

Claims (9)

A developer carrier for conveying the developer;
A regulating member that regulates the amount of developer on the developer carrying member facing the developer carrying member;
A separating member for separating the developer from the developer carrying member;
In a developing device comprising: a first developer transporting unit disposed in the vicinity of the developer carrying member and transporting the developer on one of the longitudinal sides;
The developing device includes a second developer conveying unit that conveys the developer in the same direction as or opposite to the developer conveying direction of the first developer conveying unit around the developer carrier, The second developer conveying means is provided on a side surface of the separating member on the developer carrier side, and the second developer conveying means is a skew plate, and the skew plate of the skew plate A developing device characterized in that the amount is larger than the skew plate interval. The developing device according to claim 1,
A third developer conveying means for conveying the developer in the same direction as the developer conveying direction in the first developer conveying means;
The developing device according to claim 3, wherein the third developer conveying means is a side surface of the separating member opposite to the developer carrying member. The developing device according to claim 2 ,
The regulating member is provided above the developer carrier,
The third developer conveying means is a skew plate, and conveys the developer falling downward from the regulating member in the longitudinal direction. The developing device according to claim 3,
The developing device, wherein the interval between the skew plates in the second developer conveying means is closer than the interval between the skew plates in the third developer conveying means. The developing device according to claim 3 or 4,
The developing device, wherein the skew feeding amount of the skew plate in the second developer conveying means is smaller than the skew feeding amount of the skew plate in the third developer conveying means. The developing device according to any one of claims 3 to 5 ,
The developing device, wherein the skew amount of the skew plate in the third developer conveying means is larger than the skew plate interval. The developing device according to any one of claims 1 to 6,
A developer outlet for discharging the developer from the developing device;
Providing a developer concentration detection member in the vicinity of the developer discharge port,
Based on the detection signal of the developer concentration detection member, determine the amount of toner to be newly replenished,
A developing device, comprising: a stirring unit that stirs the developer discharged from the developing device and the toner to be supplied. At least a process cartridge that integrally supports an image carrier that forms an electrostatic latent image and a developing device and is detachable from the image forming device.
A process cartridge using the developing device according to claim 1. An image carrier on which an electrostatic latent image is formed on the surface;
A developing device for visualizing the electrostatic latent image;
In an image forming apparatus comprising a developer transfer means for transferring a developer formed by mixing a toner and a carrier and developing the electrostatic latent image to the developer.
An image forming apparatus using the developing device according to claim 1.

Images