JPH07253711A - Developing device - Google Patents

Abstract

PURPOSE:To use, in the case of replenishing a developing device with fresh toner, the replenishment toner in development after its sufficient electrification, to prevent surface fog of a formed image and scatter of the toner from the developing device, resulting in soil of the inside of an image forming device, and to steadily carry out satisfactory image formation. CONSTITUTION:Circulating developer between a developer carry part 11 and a developer supply part, the developing device supplies the developer to a developing sleeve in the developer supply part to introduce it to an image carrier, and, on the other hand, replenishes the developer carry part 11 with the toner from a toner supply part provided upstream in the developer carry part 11 in the direction in which the developer is carried. The device is equipped with a preliminary stir means 20 which causes a part of the developer in the developer carry part 11 to flow into the toner supply part 12, and mixes and stirs it and the toner with which the toner supply part 12 is replenished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine or a printer,
In particular, the developer supply section that supplies the developer to the developing sleeve while conveying the developer along the axial direction of the developing sleeve that supplies the developer to the image carrier and the developer while mixing and stirring the developer is described above. Of the developer supply section for conveying the developer in the opposite direction to the developer supply section, and a toner supply section for supplying the toner to the upstream side of the developer conveyance section in the developer conveyance direction. The present invention relates to a developing device adapted to circulate between a developing section and a developer transport section.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a developing device supplies toner to an electrostatic latent image formed on an image carrier to develop the electrostatic latent image. As such a developing device, in addition to a one-component developing system using only toner as a developer, a two-component developing system using a developer containing toner and carrier has been known.

Here, in a two-component developing type developing device using a developer containing a toner and a carrier, when toner is supplied to the image bearing member for development, the toner concentration in the developer gradually increases. Therefore, when the toner concentration in the developer decreases to some extent, new toner is replenished.

When replenishing new toner in this manner, a developing device that replenishes toner along a line along the axial direction of the developing sleeve, and FIGS.
As shown in FIG. 3, a toner supply unit 12 for feeding the toner 1a is provided at the upstream side of the developer conveying unit 11 for conveying the developer 1 while mixing and stirring the developer 1 so as to be continuous with the developer conveying unit 11. Toner supply port 12 of section 12
A new toner 1a is supplied to the toner supply unit 12 from a toner bottle (not shown) or the like through a, and the new toner 1a thus supplied is sent to the developer transport unit 11 through the toner supply unit 12. In general, the developing device as shown in FIGS. 1 to 3 has a simpler and more compact mechanism for replenishing toner than a developing device that replenishes toner in a line. There is an advantage that the toner can be locally consumed and the toner can be locally consumed.

Here, in the developing device shown in FIGS. 1 to 3, as the stirring / conveying member 13 for conveying the developer 1 while mixing and stirring the developer 1 in the above-mentioned developer conveying section 11,
Generally, an agitating / conveying blade 13b provided in a spiral shape around the rotary shaft 13a in a constant state is used, and the agitating / conveying member 13 is rotated so that the developing / conveying portion 11 develops by the agitating / conveying blade 13b. The developer 1 is conveyed while being mixed and stirred, and the developer 1 thus conveyed
Is fed to the developer supply section 14 through a supply port 15a provided at one end of the partition wall 15 for separating the developer transport section 11 and the developer supply section 14.

Further, in the developer supply section 14 to which the developer 1 has been sent in this way, generally, a bucket roller 16 is provided as shown in FIGS. 1 and 2, and the bucket roller 16 is rotated and sent. The developer 1 thus conveyed is conveyed in a direction opposite to that of the developer conveying portion 11, and a part of the developer 1 is supplied to a rotating developing sleeve 18, and the developing sleeve 18 conveys the developer 1 to an image carrier. 2, the toner 1a in the developer 1 is supplied to the image carrier 2 to perform development, and the developer 1 conveyed in the direction opposite to the developer conveying section 11 as described above is separated from the partition wall. Through the return port 15b provided at the other end of 15, the developer transport unit 11
To the developer transport section 11 and the developer supply section 1
It was made to circulate between 4 and.

Then, as described above, the developer 1 is guided to the image bearing member 2 by the developing sleeve 18, and the toner 1a is supplied to the image bearing member 2 to perform the development. As a result, the density of the toner 1a in the developer 1 is increased. When the toner is low, as shown in FIG. 3, the toner replenishing port 12a is passed through the toner replenishing port 12a to the toner supplying section 12 provided on the upstream side in the conveying direction of the developer conveying section 11 so as to be continuous with the developer conveying section 11. New toner 1a is supplied from the above, and the toner 1a thus supplied is rotated by the stirring and conveying member 13 to supply the toner 1a.
From the toner 1a to the developer transport unit 11 and returned to the developer transport unit 11 through the return port 15b and the new toner 1a are put together, and the toner 1a is agitated and transported by the stirring and transporting member 13 described above. Therefore, the developer is conveyed in the developer conveying section 11 while being mixed and stirred with the developer 1.

However, the toner 1a newly replenished in this way is guided to the developer transport section 11 through the toner supply section 12, and the toner 1a is returned to the developer transport section 11 through the return port 15b. When mixed with the toner 1a, only the toner concentration of the developer 1 in the portion where the new toner 1a is replenished becomes high, and the toner 1a in the developer 1 is increased.
If the toner density in the developer 1 becomes too high as described above, the newly replenished toner 1a is not sufficiently mixed and stirred with the developer 1 in the developer transport section 11, The toner 1a is sent to the developer supplying unit 14 in a state where it is not sufficiently charged, and the toner 1a having such a poor charging is supplied to the developing sleeve 18 and used for development, and as a result, a background fog is formed on the formed image. There is a problem that the toner 1a that is generated or is not charged is scattered from the developing device and the inside of the image forming device is soiled.

Further, in order to ensure that the toner 1a newly replenished as described above is sufficiently charged in the developer transport section 11, the stirring transport provided in the developer transport section 11 is conventionally used. Although it has been considered that the stirring condition for stirring the developer 1 by the member 13 is strengthened, if the stirring condition of the developer 1 by the stirring / transporting member 13 is strengthened as described above, the stirring deteriorates the developer 1, or New problems such as a heavy load on the stirring and conveying member 13 have occurred.

[0010]

SUMMARY OF THE INVENTION According to the present invention, there is provided a developer supplying section for supplying the developer to the developing sleeve while conveying the developer along the axial direction of the developing sleeve for supplying the developer to the image carrier. A developer transport unit that transports the developer in the direction opposite to the developer supply unit while mixing and stirring the developer, and a toner supply unit that sends toner to the upstream side in the developer transport direction of the developer transport unit. An object of the present invention is to solve the above-mentioned problems in a developing device that has a developer and circulates the developer between the developer supply unit and the developer transport unit.

That is, according to the present invention, in the developing device as described above, new toner supplied from the toner bottle or the like to the toner supply unit is guided from the toner supply unit to the developer conveying unit, and inside the developer conveying unit. When the new toner is mixed with the developer and conveyed while being stirred, the newly replenished toner is conveyed without causing a charging failure or deterioration of the newly replenished toner. Image is sufficiently charged in the image forming section to be used for development, a background image is not fogged on the formed image, and toner does not scatter from the developing device to stain the inside of the image forming device. The object is to enable stable formation.

[0012]

According to the present invention, in order to solve the above-mentioned problems, a developing sleeve is fed to an image carrier while the developing sleeve is fed along the axial direction of the developing sleeve. A developer supply unit that supplies the developer, a developer transport unit that transports the developer in the opposite direction to the developer supply unit while mixing and stirring the developer, and a developer transport direction in the developer transport unit. In a developing device having a toner supply unit for feeding toner to the upstream side and circulating the developer between the developer supply unit and the developer transport unit, in the developer transport unit, Preliminary stirring means is provided to allow a part of the toner to flow into the toner supply section and to mix and stir with the toner in the toner supply section.

[0013]

In the developing device according to the present invention, while circulating the developer between the developer transport section and the developer supply section,
The developer is supplied to the developing sleeve at the developer supplying section,
The developing sleeve guides the developer to the image carrier, and the toner in the developer is supplied to the image carrier to perform the development.

When the toner concentration in the developer is lowered as a result of supplying the toner to the image bearing member and performing the development, the toner is provided on the upstream side in the developer transporting direction in the developer transporting section. New toner is supplied to the toner supply unit, and the toner thus supplied is sent from the toner supply unit to the developer transport unit.

Here, in the developing device according to the present invention, a part of the developer in the developer carrying section is made to flow into the toner supplying section to which the new toner is supplied as described above, and the toner is supplied to the toner supplying section. The mixed toner is mixed and stirred with the inflowing developer in the toner supplying section by the preliminary stirring means, and the replenished toner is pre-charged in the toner supplying section before being guided to the developer conveying section. The generated toner is gradually introduced into the developer transport unit while replacing the developer that has flowed into the toner supply unit from the developer transport unit.

In this way, the toner replenished to the toner supply section is not immediately supplied to the developer transport section and the toner concentration in the developer does not suddenly increase, and the toner is precharged as described above. The toner is gradually supplied to the developer transport section, and is transported while being sufficiently mixed and stirred with the developer in the developer transport section, and while being guided to the developer supply section, this toner is sufficiently charged and developed. It will be used.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A developing device according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings.

Also in the developing device of this embodiment, as shown in FIGS. 4 and 5, like the conventional developing device shown in FIGS. 1 and 2, the developing sleeve 18 faces the image carrier 2. And rotatably provided on the apparatus main body 10,
A partition wall 15 is provided inside the apparatus main body 10 along the axial direction of the developing sleeve 18, and the partition wall 15 conveys the developer 1 inside the apparatus main body 10 along the axial direction of the developing sleeve 18 while developing sleeve. A developer supplying section 14 for supplying the developer 1 to the nozzle 18 and a developer conveying section 11 for conveying the developer 1 in the opposite direction to the developer supplying section 14 while mixing and stirring the developer 1 are separated.

The partition wall 1 is provided at the downstream end of the developer transport section 11 in the transport direction of the developer 1.
5 is provided with a supply port 15a for feeding the developer 1 from the developer transport unit 11 to the developer supply unit 14, while the partition wall 15 is provided at the downstream end of the developer supply unit 14 in the transport direction of the developer 1. A return port 15b for returning the developer 1 from the developer supply unit 14 to the developer transport unit 11 is opened so that the developer 1 is circulated between the developer transport unit 11 and the developer supply unit 14. .

Here, in the above-mentioned developer supply section 14, the bucket roller 16 is provided inside the development sleeve 18.
Along the partition wall 15 by the rotation of the bucket roller 16
The developer 1 is conveyed from the supply port 15a side to the return port 15b side, and a part of the developer 1 is supplied to the developing sleeve 18.

On the other hand, in the developer carrying section 11, a toner supply section 12 is provided at a position upstream of the developer carrying direction in the carrying direction of the developer 1 so as to be continuous with the developer carrying section 11.
The toner supply unit 12 and the developer transport unit 11 are connected to the developer 1
Inclination is performed upward from the upstream side to the downstream side in the conveyance direction.

In the toner supply unit 12, a new toner 1a is supplied from a toner bottle (not shown) or the like.
Is supplied through the toner supply port 12a, and the toner 1a thus supplied is supplied to the developer conveying section 11 through the toner passage 12b in the toner supply section 12.

Here, the developer 1 in the developer transport section 11 is transported while being mixed and stirred, or the toner 1a replenished to the toner supply section 12 through the toner replenishing port 12a is passed through the toner passage 12b. At the time of feeding to 11, the stirring transport member 13 from the developer transport unit 11 to the toner supply unit 12 is provided.

In this embodiment, as the stirring / conveying member 13, the stirring / conveying blade for conveying the developer 1 while mixing and stirring it around the rotary shaft 13a in the portion inside the developer conveying section 11 is used. 13b is provided in a spiral shape in a constant state, while the developer 1 introduced from the developer transport unit 11 and the toner 1a in the toner passage 12b are mixed and stirred in a portion of the toner supply unit 12 inside the toner passage 12b. As the preliminary stirring means 20, a stirring blade 13c protruding in the radial direction along the axial direction of the rotating shaft 13a is provided, and the toner 1a replenished from the toner replenishing port 12a is provided below the toner replenishing port 12a. The one provided with the conveying blade 13d for feeding to the toner passage 12b is used.

Here, when the rotating shaft 13a of the stirring and conveying member 13 as described above is rotated, in the developer conveying section 11, the developer 1 is mixed and stirred by the stirring and conveying blade 13b, and the developer is supplied. The partition wall 15 is conveyed in the opposite direction from the return port 15b side toward the supply port 15a side.

On the other hand, in the toner supply section 12, FIG.
(A), the developer 1 on the upstream side in the transport direction of the developer transport unit 11 such as the developer 1 returned from the developer supply unit 14 to the developer transport unit 11 through the return port 15b. Part of the toner flows into the toner supply unit 12, and the developer 1 that has flowed in this way is stirred by the stirring blade 1 provided on the stirring / transporting member 13 as shown in FIG. 6B.
3c is flattened by the rotation, and part of it is returned to the developer transport unit 11 side and is also guided to the toner passage 12b on the toner replenishing port 12a side. Toner supply port 1 in 12b
The toner 1a replenished from 2a and the stirring blade 13c are mixed and stirred, and the replenished toner 1a is precharged.

In the conventional developing device shown in FIGS. 1 and 2, a part of the developer 1 on the upstream side of the developer carrying section 11 in the carrying direction flows into the toner supplying section 12.
In the conventional developing device, as the stirring / conveying member 13, as described above, the stirring / conveying blade 13b is provided around the rotating shaft 13a.
Since the toner is simply provided in a spiral shape in a constant state, the developer 1 is supplied to the toner supply unit 12 as described above.
Even if the developer flows in, as shown in FIG. 3, the developer 1 that has flowed in is suppressed by the agitating and conveying blade 13b, and the developer 1 does not flow into the toner supply unit 12 any more. 1 is a stirring and conveying blade 13
By the rotation of b, the developer 1 is returned to the developer transport unit 11. As in the developing device of this embodiment, the developer 1 that has flowed in is mixed and stirred with the toner 1a supplied in the toner supply unit 12, and is supplied. The toner 1a was never precharged.

Next, the case where development is performed by using the developing device in this embodiment will be specifically described.

In this developing device, the developer transport section 1
By rotating the agitating / conveying blade 13b of the agitating / conveying member 13 provided inside 1, the developer 1 in the developer conveying section 11 is mixed and agitated from the return port 15b side of the partition wall 15 to the supply port 15a side. The developer 1 is conveyed and sent to the developer supply unit 14 through the supply port 15a.

Then, the developer 1 thus fed to the developer supply unit 14 is mixed and stirred by the rotation of the bucket roller 16 provided in the developer supply unit 14, and is mixed with the developer transport unit 11. While transporting in the opposite direction,
A part of the developer 1 is supplied to the developing sleeve 18, the developer 1 guides the developer 1 to the image carrier 2, and the toner 1a in the developer 1 is supplied to the image carrier 2. Along with the development, the developer 1 conveyed in the opposite direction to the developer conveying section 11 is returned to the developer conveying section 11 through the return port 15b provided at the other end of the partition wall 15. .

When the toner 1a is supplied to the image carrier 2 as described above and developed as a result, and the concentration of the toner 1a in the developer 1 decreases, a new toner is discharged from the toner bottle or the like. 1a is supplied to the toner supply unit 12 through the toner supply port 12a.

In this way, when new toner 1a is supplied to the toner supply unit 12 through the toner supply port 12a,
The supplied new toner 1a is guided to the toner passage 12b by the rotation of the conveying blade 13d provided on the stirring and conveying member 13, and the toner 1a introduced into the toner passage 12b as described above. And stirring and conveying member 13
The mixture was agitated by the agitating blade 13c provided in the above and precharged.

The toner 1a thus pre-charged is gradually moved to the developer conveying section 11 side together with the developer 1 in the toner passage 12b, and the developer conveying section 1 is
While being replaced with the developer 1 that flows into the toner supply unit 12 from 1, the developer 1 is introduced into the developer transport unit 11 together with the developer 1 returned to the developer transport unit 11 through the return port 15b. In the developer transport section 11, the developer is transported while being mixed and stirred as described above.

The new toner 1a thus replenished to the toner supply unit 12 is pre-charged before being guided to the developer transport unit 11, and the pre-charged toner 1a is gradually supplied into the developer transport unit 11. By doing so, the toner concentration in the developer 1 in the developer transport unit 11 does not rise rapidly, and the new toner 1a replenished in the toner supply unit 12 is stirred and transported in the developer transport unit 11. By the blades 13b, the developer 1 is sufficiently charged while being mixed and stirred with the developer 1 before being conveyed to the supply port 15a, and a background fog occurs in the formed image, or the toner 1a scatters from the developing device. The inside of the forming apparatus was not contaminated, and good image formation could be performed stably.

In the developing device of this embodiment,
The developer 1 that has flowed into the toner supply unit 12 from the developer transport unit 11 and the toner 1a that has been replenished to the toner supply unit 12
As a preliminary stirring means 20 for preliminarily charging the replenished toner 1a by mixing and stirring
In the agitating and conveying member 13, the agitating blade 13c protruding in the radial direction along the axial direction is provided at the portion of the rotating shaft 13a in the toner supplying unit 12.
The pre-stirring means 20 is not particularly limited to this.

For example, as shown in FIG. 7, in the portion of the agitating and conveying member 13 in the toner supplying section 12, a plurality of small agitating blades 13e radially protruding along the axial direction of the rotating shaft 13a are provided. In order to increase the speed at which the toners 1a that are pre-charged are provided in a staggered manner in order to guide the pre-charged toner 1a to the developer transport unit 11, as shown in FIG. Stirring blade 13c protruding in the radial direction along the axial direction
And a semi-circular conveying blade 13f for feeding the pre-charged toner 1a to the developer conveying portion 11 and a stirring blade 13
As shown in FIG. 9, the agitation is performed in reverse to the case of FIG. 8 so that the developer 1 can be attached to one side of c and the developer 1 can quickly flow into the toner supply unit 12 from the developer transport unit 11. The conveying blade 13g in the opposite direction may be attached to one surface of the blade 13c, and further, the stirring and conveying member 13 described above.
Alternatively, the preliminary stirring means 20 may be provided separately.

[0037]

As described above in detail, in the developing device according to the present invention, the developer is supplied to the developing sleeve while being circulated between the developer conveying portion and the developer supplying portion. When the toner concentration in the developer decreases as a result of the development, the toner is replenished to the toner supply unit provided on the upstream side in the conveying direction of the developer conveying unit, and the toner is supplied to the developer conveying unit. In supplying the developer into the developer, a part of the developer in the developer transport section is caused to flow into the toner supply section, and the replenished toner is mixed and stirred in the toner supply section by the developer and the preliminary stirring means. Then, the replenished toner is pre-charged before being guided to the developer transport unit.

Therefore, in the developing device of the present invention, the toner pre-charged in the toner supply section as described above is gradually conveyed while replacing the developer flowing into the toner supply section from the developer conveyance section. Led to the department,
The toner concentration in the developer in the developer transport section does not suddenly increase due to the toner replenished to the toner supply section, and the toner precharged as described above is gradually supplied to the developer transport section. As a result, the toner is mixed and stirred with the developer in the developer conveying section, and while being introduced into the developer supplying section, the toner is sufficiently charged and used for development.

As a result, in the developing device according to the present invention, when the toner is replenished to the toner supply portion as described above, the toner concentration in the developer is partially increased as in the conventional developing device. The supplied toner is not sufficiently charged and used for development, and the developer is not deteriorated because the supplied toner is sufficiently charged. It is possible to stably perform good image formation without causing background fogging in the image used for development and causing toner to scatter from the developing device to stain the inside of the image forming device. .

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a state in which the inside of a conventional developing device is viewed from a developer transport unit side.

FIG. 2 is a schematic cross-sectional view showing a state in which the inside of the conventional developing device is viewed from the upper surface side.

FIG. 3 is a schematic cross-sectional view showing a state in which the toner supplied to the toner supply unit is supplied to the developer transport unit in the conventional developing device.

FIG. 4 is a schematic cross-sectional view showing a state in which the inside of the developing device according to the embodiment of the present invention is viewed from the developer transport section side.

FIG. 5 is a schematic cross-sectional view showing the inside of the developing device according to the embodiment of the present invention as viewed from the upper surface side.

FIG. 6 is a partially enlarged view showing a state in which the toner supplied to the toner supply unit and the developer introduced from the developer transport unit are mixed and stirred in the toner supply unit in the developing device according to the embodiment of the present invention. FIG.

FIG. 7 is a developing device according to another embodiment of the present invention, in which a preliminary stirring means for mixing and stirring the toner supplied to the toner supply section and the developer introduced from the developer transport section in the toner supply section is changed. FIG.

FIG. 8 is a developing device according to another embodiment of the present invention, in which a preliminary stirring means for mixing and stirring the toner supplied to the toner supply section and the developer introduced from the developer transport section in the toner supply section is changed. FIG.

FIG. 9 is a developing device according to another embodiment of the present invention, in which a preliminary stirring unit for mixing and stirring the toner supplied to the toner supply unit and the developer introduced from the developer transport unit in the toner supply unit is changed. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 developer 1a toner 2 image carrier 11 developer transport unit 12 toner supply unit 13 stirring transport member 13a rotating shaft 13b stirring transport blades 13c and 13e stirring blades (preliminary stirring means) 14 developer supply unit 15 partition wall 15a supply port 15b Return port 16 Bucket roller 18 Developing sleeve 20 Preliminary stirring means

Claims (1)

[Claims] 1. A developer supplying section for supplying the developer to the developing sleeve while conveying the developer along the axial direction of the developing sleeve for supplying the developer to the image carrier, and developing while mixing and stirring the developer. The developer transport section for transporting the developer in the direction opposite to the developer supply section, and the toner supply section for sending the toner to the upstream side in the developer transport direction in the developer transport section, In a developing device adapted to circulate between a developer supply section and a developer transport section, a part of the developer in the developer transport section is caused to flow into the toner supply section to be mixed and stirred with the toner in the toner supply section. A developing device provided with a pre-stirring means for performing the stirring.