JPH10207201A - Two-component developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of defective draw up of developer by a developer carrier with an easy constitution and to obtain a good image by making the shaft diameter of a 1st developer stirring member larger on the downstream side in a developer carrying direction. SOLUTION: As for the shaft diameter of the shaft part 2a of the 1st stirring roller 2, a part corresponding to the downstream area is made larger than a part corresponding to the upstream area 1 in the developer carrying direction. Thus, the gap capacity between the 1st developer storing part 7a and the 1st stirring roller shaft part on the downstream side is made smaller than that in the upper stream side area, then, even in the case the developer capacity in the 1st developer storing part is reduced in the downstream area in the developer carrying direction, the uppermost level of the developer is controlled to become higher, because the gap for storing the developer 8 is small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.
A developer carrying member for carrying a developer, and a first and a second carrier for conveying the developer along the axial direction of the developer carrying member while stirring the developer and circulating the developer through a circulation path formed between the two. A second developer stirring / transporting means, wherein the developer carrier is disposed above the first and second developer stirring / transporting means, and the first developer stirring / transporting is carried out by the developer carrier. The present invention relates to a two-component developing device having a developer conveying path for drawing up the developer on the means side and conveying the same to a developing area, and separating the developer after passing through the developing area to the second stirring and conveying means side.

[0002]

2. Description of the Related Art Conventionally, there have been proposed various developing devices in which a developer carrying member is disposed above a developer stirring and conveying section. For example, Japanese Patent Application Laid-Open No. Hei 4-60665 discloses that a first and a second stirring / conveying section are provided side by side as a developer stirring / conveying section, and a developer conveying path by a developing sleeve as a developer carrying member is provided. (1) The developer pumped up from the agitating / transporting unit side is transported to almost immediately below the photoreceptor serving as a latent image carrier, and the developer on the developing sleeve after passing through the developing area is transported to the second agitating / transporting unit side. A developing device configured to be removed from the sleeve is disclosed. In this developing device, the first and second stirring / transporting units are arranged side by side, so that the apparatus can be made flatter than in a case where these are not arranged side by side.

[0003]

However, in the developing device disclosed in JP-A-4-60665, the first type
Since a part of the developer in the stirring / transporting section is pumped up by the developing sleeve while being transported from the upstream side to the downstream side,
When the developer is continuously pumped up by the developing sleeve, the amount of the developer in the first stirring / conveying unit is smaller on the downstream side than on the upstream side, and the height of the uppermost surface of the developer is reduced. There is a possibility that poor pumping may occur, in which the amount of developer pumped by the developing sleeve at the portion is reduced. When this poor pumping occurs, there is a problem that the density of the image corresponding to the poor pumping portion is reduced.

In order to prevent the poor pumping of the developer, the amount of the developer to be supplied into the developer agitating / conveying section is increased, or a screw or the like is used as the developer agitating / conveying member in the first and second agitating / conveying sections. For example, it is conceivable to increase the rotation speed of the screw when the screw is used. However, when the amount of the developer is increased, the size of the developing unit including the developer agitating and conveying unit is increased. Also, the first
When the rotation speed of the screw or the like in the second stirring / transporting unit is increased, the wear of the bearing member of the screw and the stress applied to the developer increase, and the life of the developer decreases.
Therefore, it is not preferable to increase the amount of the developer or the rotational speed of the screw.

[0005] The present invention has been made in view of the above problems, and has as its object the purpose of the present invention to reduce the amount of developer and the first
In addition, it is possible to prevent the developer from being poorly pumped up by the developer carrying member and to obtain a good image while maintaining the rotation speed of the developer stirring and conveying member in the second stirring and conveying section as it is. It is to provide a developing device which can be used.

[0006]

According to another aspect of the present invention, there is provided a two-component developing apparatus comprising: a developer carrying member for carrying a developer; A first and a second transporting the developer along an axial direction of the developer carrier and circulating the developer through a circulation path formed between the two.
Developer agitating / conveying means, and the developer carrier is
And a second developer agitating / transporting means disposed above the first developer agitating / transporting means side of the first developer agitating / transporting means in the developer container. A developer transport path for transporting the developer to the developing area, and separating the developer after passing through the developing area to a second developer accommodating portion on the side of the second stirring and transporting means of the developer accommodating device. In the component developing device, the first developer stirring / transporting means includes a first developer having a shaft portion extending in a developer transport direction along an axial direction of the developer carrier in the first developer accommodating portion. The shaft portion is constituted by a stirring and conveying member, and the shaft diameter of the shaft portion is larger at a portion corresponding to the downstream side than at a portion corresponding to the upstream side in the developer conveying direction.

In the two-component developing device of the first aspect, the first developer for stirring and transporting the developer pumped to the developer carrier is provided.
The shaft diameter of the developer stirring / conveying member is made larger at the shaft portion corresponding to the downstream side in the developer conveyance direction than at the shaft portion corresponding to the upstream side, and the developer is accommodated at the downstream side. The void volume between the first developer accommodating portion and the shaft of the first developer stirring member is reduced as compared with the upstream side. As a result, even if the developer capacity in the first developer accommodating portion is reduced on the downstream side in the developer transport direction, the height of the uppermost surface of the developer is increased with a small amount of the developer, and the developer located above Ensure good pumping on the carrier.

Here, for example, if the shaft diameter of the first developer stirring member is increased at a portion corresponding to the upstream side in the developer transport direction, the shaft of the first developer accommodating portion and the shaft of the first developer stirring member are also increased at this portion. The volume of the gap between the first and second portions is reduced, so that the amount of the developer decreases, and the amount of the developer supplied downstream thereof decreases. The two-component developing device of the present invention does not increase the shaft diameter of the first developer agitating member in the portion corresponding to the upstream side in the developer transport direction, so that the downstream side caused by increasing the shaft diameter on the upstream side is not used. There is no decrease in the developer supply.

According to a two-component developing device of the present invention, in the two-component developing device of the first aspect, the shaft diameter of the shaft portion of the first developer stirring and conveying member is gradually increased from the upstream side to the downstream side in the developer conveying direction. It is characterized by being enlarged.

Further, in the two-component developing device according to the second aspect, the shaft diameter of the first developer stirring and conveying member for stirring and conveying the developer pumped up by the developer carrier is changed from the upstream side to the downstream side in the developer conveying direction. The volume of the gap between the first developer accommodating portion for accommodating the developer and the shaft portion of the first developer agitating member is reduced toward the downstream side. As a result, the height of the uppermost surface of the developer can be maintained high even with a smaller amount of developer toward the downstream side in the developer transport direction, so that the developer carrying member located above can satisfactorily pump the developer.

Further, the shaft diameter of the first developer stirring and conveying member is
When the shaft portion corresponding to the downstream side in the developer transport direction has a constant size that is larger than that of the shaft portion corresponding to the upstream side, the upstream side in the developer transport direction in the portion where the shaft diameter is increased. Further, there is a possibility that the supply amount of the developer to the downstream side may decrease due to a decrease in the volume of the gap between the first developer accommodating portion and the shaft portion of the first developer stirring member. If the shaft diameter of the first developer stirring member is increased in accordance with the decrease in the amount of the developer, at least the space between the first developer accommodating portion and the shaft portion of the first developer stirring member is reduced. Thus, it is possible to prevent the supply amount of the developer to the downstream side from decreasing.

According to a third aspect of the present invention, there is provided a two-component developing device, comprising: a developer carrying member for carrying a developer; and the developer carrying member is transported along the axial direction of the developer carrying member while stirring the developer in a developer container. And a first and second developer stirring and conveying means for circulating the developer in a circulation path formed between the first and second developer stirring and conveying means. Disposed above the developer carrying member, the developer on the side of the first developer stirring and conveying means in the developer container is pumped up and conveyed to the developing area, and further after passing through the developing area. In the two-component developing device, a developer transport path configured to separate the developer toward the second stirring / transporting means side of the developer container is provided.
The developer stirring / conveying means includes a first developer stirring / conveying member having a screw extending in the developer conveying direction along the axial direction of the developer carrier, and developing the pitch of the screw in the axial direction. It is characterized in that it is smaller in the downstream region than in the upstream region in the agent transport direction.

Here, when the pitch of the screw is small, the developer conveying speed becomes slower than when the pitch is large.

According to a third aspect of the present invention, in the screw as the first developer stirring and conveying means extending in the developer conveying direction along the axial direction of the developer carrying member, the screw extends in the axial direction. Is made smaller in the downstream region than in the upstream region in the developer transport direction, and the developer transport speed by the screw on the downstream side is made slower than that in the upstream side. This prevents the developer conveyed from the upstream from staying in the downstream region for a long time to prevent the amount of the developer on the downstream from decreasing. , So that the developer can be satisfactorily pumped up.

Here, for example, if the pitch in the axial direction of the screw is reduced even in the region upstream of the developer transport direction, the transport speed of the developer is also reduced in this portion, and the amount of developer flowing downstream therefrom decreases. Would. Since the two-component developing device of the present invention does not reduce the screw pitch in the area on the upstream side in the developer transport direction, a decrease in the amount of the developer supplied to the downstream side caused by reducing the screw pitch on the upstream side does not occur. .

The two-component developing device according to a fourth aspect of the present invention is the two-component developing device according to the third aspect, wherein a pitch of the screw of the first developer stirring and conveying member in the axial direction is set downstream from an upstream side in the developer conveying direction. It is characterized in that it is gradually reduced toward the side.

According to a fourth aspect of the present invention, in the screw as the first developer stirring and transporting means extending in the developer transporting direction along the axial direction of the developer carrying member, in the above-mentioned axial direction of the screw, Gradually decreases from the upstream side to the downstream side in the developer transport direction,
The developer transport speed by the screw is gradually reduced as it goes downstream. As a result, the transport speed of the developer is reduced in the downstream region where the amount of the developer tends to decrease, and the height of the uppermost surface of the developer is maintained high by preventing the developer amount from decreasing. The developer can be pumped well by the developer carrier located there.

If the pitch in the axial direction of the screw is set to a constant value that is smaller in the downstream area in the developer transport direction than in the upstream area, the upstream of the screw pitch in the developer transport direction in the reduced area. Side, there is a possibility that the developer supply amount to the downstream side may decrease due to the slow developer transport speed. If the screw pitch is reduced in accordance with the decrease in the developer, it is possible to avoid a decrease in the developer supply amount to the downstream side due to at least a slow developer transport speed.

The two-component developing device according to the fifth aspect of the present invention is a developer carrying member for carrying a developer, and the developer carrying member is conveyed along the axial direction of the developer carrying member while stirring the developer in a developer container. A first path for circulating the developer through a circulation path formed between the first and second paths;
And a second developer stirring / transporting means, wherein the developer carrier is disposed above the first and second developer stirring / transporting means, and the developer container is provided by the developer carrier. Developing the developer on the side of the first developer stirring / transporting means and transporting the developer to the developing area, and further separating the developer after passing through the developing area to the second stirring / transporting means side of the developer container. In the two-component developing device having a developer conveying path, the first developer stirring / conveying means scrapes the developer upward at a downstream side in a developer conveying direction along the axial direction of the developer carrier. It has a raising means.

In the two-component developing device according to the fifth aspect, the developer conveyed along the axial direction of the developer carrying member in the developer container is moved up by the scraping means on the downstream side in the developer conveying direction. Raise it upwards. As a result, the height of the uppermost surface of the developer is forcibly increased even on the downstream side where the amount of the developer is reduced, so that the developer is favorably pumped up by the developer carrier positioned above. .

The two-component developing device according to a sixth aspect of the present invention is the two-component developing device according to the fifth aspect, wherein the first developer stirring and conveying means is provided along the axial direction of the developer carrier in the developer container. A first developer stirring / conveying member having a shaft portion extending in the developer conveying direction, wherein the scraping means is provided in a region of the shaft portion on the downstream side in the developer conveying direction and is rotated by rotation of the shaft portion. The present invention is characterized in that the developer is constituted by scraping blades which scrape the developer upward.

In the two-component developing apparatus according to the sixth aspect, only the developer in a region on the downstream side in the developer conveying direction is scraped by the rotation of the shaft by a lifting blade provided on the shaft of the first developer stirring and conveying member. Even if the developer amount is smaller than the upstream side, the height of the uppermost surface of the developer is increased so that the developer can be satisfactorily pumped up by the developer carrier positioned above.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] An embodiment (hereinafter, referred to as Embodiment 1) in which the present invention is applied to a developing device used in an electrophotographic copying machine (hereinafter, referred to as "copier") as an image forming apparatus will be described. FIG. 1 shows a developing device 9 according to this embodiment.
It is sectional drawing which shows schematic structure of. The developing device 9 is provided below a cylindrical photosensitive drum 6 as a latent image carrier, and has a casing 7 as a developer container having an opening formed toward the photosensitive drum 6, A developing sleeve 1 which is partially exposed from the opening and which carries a two-component developer (hereinafter referred to as a developer) 8 composed of a toner and a carrier on a surface thereof; The image forming apparatus includes first and second stirring rollers 2 and 3 as a developer stirring and conveying unit, and a doctor blade 4 that regulates the amount of the developer 8 carried on the developing sleeve 1 and conveyed to the developing area.

The first and second stirring rollers 2 and 3 are provided with shafts 2a and 3a extending in a developer conveying direction along the axial direction of the developing sleeve, and a plurality of shafts on the shafts 2a and 3a. And a screw blade portion 2b, 3b formed in a spiral shape. And the first and second stirring rollers 2 and 3 are
By rotating the shafts 2a, 3a, the screw blades 2b,
At 3b, the developer is agitated and transported along the axial direction of the developing sleeve 1.

FIG. 2 is a sectional view of the developing device 9 taken along the line XX 'of FIG. A partition plate 5 provided between the first stirring roller 2 and the second stirring roller 3 forms a first developer container 7a and a second developer container 7b in the casing 7. The developer in the second developer container 7b is
The toner is conveyed along the axis of the developing sleeve 1 in the direction of arrow B while being agitated by the agitating roller 3, passes through the gap between the partition plate 5 and the casing 7 as shown by the arrow D, and is on the first developer accommodating portion 7 a side Passed to. On the other hand, the developer in the first developer accommodating portion 7a is conveyed along the axial direction of the developing sleeve 1 in the direction of arrow C while being stirred by the first stirring roller 2, and is separated from the partition plate 5 as shown by arrow E. The developer passes through the gap between the casing 7 and the second developer accommodating portion 7b. That is, the arrows B, D,
A biaxial stirring circulation path for circulating the developer in the C and E directions is formed.

The developing sleeve 1 disposed above the first and second stirring rollers 2 and 3 includes a magnet roller comprising a fixed magnet group as a magnetic field generating means (not shown), A sleeve that rotates while contacting the outer periphery. The magnetic pole of the magnet roller is configured such that the developer on the developing sleeve 1 is separated by its own weight toward the second developer accommodating portion 7b. The developer in the first developer accommodating portion 7a is pumped up by the developing sleeve 1 and is conveyed to a developing area facing the photosensitive drum 6 by the rotation of the sleeve 1. further,
After passing through the developing area, the developer is transported to the second developer accommodating portion 7b side and falls. That is, by the developing sleeve 1,
A bypass path indicated by arrow A is formed.

In the developing device having the above-described structure, the developer 8 in the first developer accommodating portion 7a is pumped up by the magnetic force of the developing sleeve 1 and is rotated in the direction of the arrow while being carried on the sleeve 1. Is transported along with. The developer 8 is regulated and thinned by the doctor blade 4, and is conveyed to a developing area facing the photosensitive drum 1.
In the developing area, toner is supplied to the electrostatic latent image formed on the photosensitive drum 1, and the electrostatic latent image is visualized. Then, the developer on the developing sleeve 1 after passing through the developing area is conveyed to the second developer accommodating portion 7b side with the rotation of the sleeve 1, separated from the sleeve 1 by its own weight, and separated into the second liquid reservoir 7b. Fall into.

FIG. 3 is a sectional view of the conventional developing device taken along the line YY 'in FIG.
3A is a cross-sectional view of a portion located on the downstream side in the developer transport direction. As described above, the bypass path indicated by the arrow A extends from the first developer container 7a to the second developer container 7b.
Therefore, when the developer is continuously pumped up by the developing sleeve 1, the amount of the developer in the first developer accommodating portion 7a is larger than that in the upstream side in the developer conveying direction. 3, the height of the uppermost surface of the developer 8 on the downstream side may be reduced, and the amount of the developer 8 pumped by the developing sleeve at that portion may be reduced. Therefore, in the first embodiment, even if the amount of the developer decreases on the downstream side of the first developer accommodating portion 7a in the developer transport direction, the height of the uppermost surface of the developer 8 is increased.
The stirring roller 2 is devised.

FIG. 4 is an explanatory view of the first stirring roller 2 according to the first embodiment, and FIG. 5 is a sectional view of the developing device to which the present invention is applied, taken along the line YY 'in FIG. The first agitating roller 2 has a shaft area 2a having a shaft diameter that is smaller on the downstream side than the area corresponding to the area l on the upstream side in the developer transport direction.
The part corresponding to is enlarged. Thus, in the downstream region m, the void volume between the first developer accommodating portion 7a and the first stirring roller shaft portion 2a is reduced as compared with the upstream region l, and the downstream region in the developer transport direction is reduced. Even if the developer volume in the first developer accommodating portion 7a decreases in the region m, as shown in FIG. 5, the height of the uppermost surface of the developer 8 is small because the space for accommodating the developer 8 is small. To be higher. When the height of the uppermost surface of the developer 8 is increased, the developer 8 can be satisfactorily pumped up by the developing sleeve 1 with the current amount of the developer and the current rotational speed of the stirring rollers 2 and 3.

Here, for example, if the shaft diameter of the first stirring roller 2 is also increased in the area l on the upstream side in the developer conveyance direction, the gap for accommodating the developer 8 is also reduced in the area l and the downstream side has Since the amount of the developer supplied to the region m is further reduced, poor pumping of the developer 8 from the developing sleeve 1 is likely to occur. However, according to the developing device of the first embodiment, since the shaft diameter of the first developer stirring member corresponding to the upstream region 1 is not increased, the shaft diameter of the upstream region 1 is increased. This does not cause a decrease in the amount of developer supplied to the downstream side m.

FIG. 6 shows a first modification of the first embodiment.
FIG. 3 is an explanatory diagram of a stirring roller 2. This first stirring roller 2
Is that the shaft diameter of the shaft portion 2a is gradually increased from the upstream side to the downstream side in the developer transport direction, and the downstream side, the more the developer 8
The space between the first developer accommodating portion 7a for accommodating the shaft and the shaft portion 2a of the first current stirring roller 2 is reduced. Thereby, even if the developer capacity in the first developer accommodating portion 7a decreases toward the downstream side in the developer transport direction, the gap for accommodating the developer 8 gradually decreases. The height of the uppermost surface of the developer 8 can be maintained high with a smaller amount of the developer 8, and the developing sleeve is different from the above-described configuration in which the shaft diameter is changed in two stages of the upstream side l and the downstream side m in the developer conveying direction. 1 allows the developer 8 to be pumped better.

Further, in the modification of the first embodiment, the first stirring roller 2 is used in accordance with the degree of the decrease of the developer 8.
By increasing the shaft diameter of the, without slowing down the developer transport speed of the portion where the developer amount has not decreased,
It is possible to more effectively prevent poor pumping of the developer 8.

As described above, the first embodiment has a simple structure in which the shaft diameter of the first stirring roller 2 is increased on the downstream side in the developer conveyance direction, and prevents the developing sleeve 1 from pumping up the developer 8 poorly. can do. Thereby, the first
The pumping failure of the developer 8 to the developing sleeve 1 does not occur on the downstream side of the developer accommodating section 7a in the developer conveying direction,
Good images can be obtained.

[Second Embodiment] Next, a developing device according to another embodiment (hereinafter, referred to as a second embodiment) of the present embodiment will be described. The developing device 9 of the second embodiment basically has the same configuration as that of the first embodiment. The first embodiment is different from the first embodiment in that a shaft diameter of the first stirring roller 2 is set in the first developer accommodating portion 7a in order to keep the height of the uppermost surface of the developer 8 downstream in the developer conveying direction high. On the other hand, in the second embodiment, the pitch of the screw blade portions 2b of the first stirring roller 2 is smaller on the downstream side in the developer transport direction than on the upstream side. Hereinafter, this point will be described.

FIG. 7 is an explanatory view of the first stirring roller 2 according to the characteristic portion of the second embodiment. This first stirring roller 2
The pitch of the screw blades 2b is reduced in the downstream region m as compared with the upstream region l in the developer transport direction, and the developer transport speed by the screw blades 2b in the downstream region is increased to the upstream region l. At a later time, the developer 8 conveyed from the upstream side is retained in the downstream region m for a long time. As a result, while the developer 8 in the first developer accommodating portion 7a is conveyed downstream, a part of the developer is pumped up by the developing sleeve 1, and the amount of the developer supplied to the region m on the downstream side tends to decrease. However, the amount of the developer can be prevented from decreasing even in the downstream region m, and the height of the uppermost surface of the developer 8 in the downstream region m is kept high, so that the developing sleeve 1 located above Can be pumped well.

Here, for example, if the pitch of the screw blade portion 2b in the axial direction is reduced even in the region l on the upstream side in the developer conveying direction, the conveying speed of the developer is also reduced in this region, and the region m on the downstream side is reduced. The amount of the flowing developer decreases. Since the developing device 9 of the present invention does not reduce the screw pitch in the region l on the upstream side in the developer transport direction,
There is no decrease in the amount of developer supplied to the downstream region m due to the reduction of the screw pitch in the upstream region l.

FIG. 8 is a schematic diagram showing the pitch of the screw blades 2b of the first stirring roller 2 according to a modification of the second embodiment with respect to one screw blade 2b. The first stirring roller 2 gradually reduces the pitch of the screw blade portion 2b from the upstream side to the downstream side in the developer transport direction, and gradually decreases as the developer 8 transport speed by the screw blade portion 2b goes downstream. Like that.
In order to make the screw blade portion 2b multi-row, a plurality of such screw blade portions 2 are attached to the shaft portion of the first stirring roller 2.
b may be provided. Thereby, the first developer accommodating portion 7a
The amount of the developer 8 is prevented from decreasing toward the downstream side, so that the height of the uppermost surface of the developer 8 is kept high, and the developer 8 can be well pumped by the developing sleeve 1 located above.

Further, in the modification of the second embodiment, the pitch of the screw blade portion 2b is reduced in accordance with the degree of decrease of the developer 8, so that the development of the portion where the amount of the developer is not decreased is performed. It is possible to more effectively prevent poor pumping of the developer 8 without reducing the developer conveying speed.

As described above, the second embodiment has a simple structure in which the pitch of the screw blade portions 2b of the first stirring roller 2 is reduced on the downstream side in the developer conveying direction. Poor pumping can be prevented. Accordingly, a good image can be obtained without causing poor pumping of the developer 8 to the developing sleeve 1 downstream of the first developer accommodating portion 7a in the developer conveying direction.

Third Embodiment Next, a developing device according to another embodiment of the present embodiment (hereinafter, referred to as a third embodiment) will be described. The developing device 9 of the third embodiment basically has the same configuration as that of the first embodiment. The first embodiment is different from the first embodiment in that the height of the uppermost surface of the developer 8 is kept high even if the amount of the developer downstream in the developer transport direction decreases in the first developer accommodating portion 7a. In contrast to the shaft diameter of the first stirring roller 2 being adjusted, the third embodiment has a point that the first stirring roller 2 is provided with a paddle 2c as a scraping blade for scraping up the developer 8 in the developer accommodating portion. It is. Hereinafter, this point will be described.

FIG. 9 is an explanatory diagram of the first stirring roller 2 according to the characteristic portion of the third embodiment. This first stirring roller 2
The paddle 2c is provided only in the shaft portion 2a corresponding to the region m on the downstream side in the developer transport direction. This paddle 2c is provided with four blades radially extending in the axial direction of the first stirring roller 2 shaft portion 2a in the circumferential direction of the shaft portion. First
When the stirring roller 2 rotates, the paddle 2c also rotates together with the shaft, and places the developer 8 in the first developer accommodating portion 7a and lifts it up. As a result, even if the amount of the developer is smaller in the area m on the downstream side in the developer transport direction of the first developer accommodating portion 7a than in the area l on the upstream side, the developer 8 is scraped up and the uppermost surface is formed. Is higher, and the developing sleeve 1 located above is well pumped.

As described above, Embodiment 3 has a simple structure in which the paddle 2 c is provided on the shaft of the first stirring roller 2, and can prevent poor pumping of the developer 8 by the developing sleeve 1. As a result, the first developer container 7
A good image can be obtained without causing poor pumping of the developer 8 to the developing sleeve 1 on the downstream side in the developer transport direction a.

In the first to third embodiments, since the amount of the developer and the number of revolutions of the first and second stirring rollers 2 and 3 are not changed, the developing unit is increased by increasing the amount of the developer. The developer 8 can be satisfactorily pumped up by the developing sleeve 1 without increasing the rotational speed of the stirring rollers 2 and 3 and promoting the wear of the bearing and shortening the life of the developer.

The developing device 9 according to the first to third embodiments is used.
In order to satisfactorily pump up the developer 8 by the developing sleeve 1, adjustment of the shaft diameter of the first stirring roller shaft portion 2a, adjustment of the pitch of the screw blade portion 2b, and paddle to the first stirring roller 2 are performed. Although the application of 2c is performed independently, the first stirring roller 2 having two or more of the above three configurations may be used. By using the first stirring roller 2 having two or more configurations, it is possible to more effectively pump up the developer 8 by the developing sleeve 1.

[0045]

According to the two-component developing apparatus of the present invention, the developer amount and the number of rotations of the developer stirring and conveying member in the first and second stirring and conveying sections are maintained as they are, while the developer is maintained. With a simple configuration in which the shaft diameter of the shaft portion of the stirring and conveying member is increased at a portion corresponding to the downstream side in the developer conveying direction, poor pumping of the developer by the developer carrier can be prevented, and a good image can be obtained. There is an excellent effect.

In particular, according to the two-component developing device of the present invention, the developer amount and the number of rotations of the developer stirring / conveying member in the first and second stirring / conveying sections are maintained as they are.
The easy configuration of increasing the shaft diameter of the shaft portion of the developer agitating and conveying member toward the downstream side in the developer conveying direction can more effectively prevent poor developer pumping by the developer carrying member and provide a good image. There is an excellent effect that it can be obtained.

According to the two-component developing device of the third aspect, the first developer is maintained while maintaining the amount of the developer and the rotational speed of the developer stirring and conveying member in the first and second stirring and conveying sections as they are. A simple configuration in which the pitch of the screw as the agitating / conveying means is changed between an upstream area and a downstream area in the developer conveying direction can prevent poor developer pumping by the developer carrier and obtain a good image. There is an excellent effect that can be.

Further, according to the two-component developing device of the fourth aspect, the developer amount and the number of rotations of the developer stirring / conveying member in the first and second stirring / conveying sections are maintained as they are, while maintaining the current state.
A simple configuration in which the pitch in the axial direction of the transport screw as the first developer agitating and transporting means is gradually reduced from the upstream side to the downstream side in the developer transport direction, thereby more effectively reducing the poor pumping of the developer by the developer carrier. This has an excellent effect that a good image can be obtained.

According to the two-component developing device of the present invention, the amount of the developer and the number of rotations of the developer stirring and conveying member in the first and second stirring and conveying sections are maintained as they are, while maintaining the current state.
With the simple configuration in which the first developer stirring and conveying means is provided with a scraping means, there is an excellent effect that it is possible to prevent poor pumping of the developer by the developer carrier and obtain a good image.

According to the two-component developing device of the present invention, the developer amount and the number of rotations of the developer stirring and conveying member in the first and second stirring and conveying sections are maintained as they are, while maintaining the current state.
With a simple configuration in which a scraping blade is provided on the shaft portion of the first developer stirring and conveying member, it is possible to prevent the developer from being poorly pumped up by the developer carrier and to obtain an excellent effect that a good image can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a developing device to which the present invention can be applied.

FIG. 2 is a cross-sectional view of the developing device taken along a line XX ′ of the arrow.

FIG. 3 is a sectional view taken along the line YY ′ in FIG. 2;

FIG. 4 is an explanatory diagram of a first stirring roller according to the first embodiment.

FIG. 5 is a sectional view taken along the line YY ′ in FIG. 2 according to the first embodiment;

FIG. 6 is an explanatory diagram of a first stirring roller according to a modified example of the first embodiment.

FIG. 7 is an explanatory diagram of a first stirring roller according to a characteristic portion of the second embodiment.

FIG. 8 is a schematic diagram of a pitch of a screw blade portion of a first stirring roller according to a modification of the second embodiment.

FIG. 9 is an explanatory diagram of a first stirring roller according to a characteristic portion of the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing sleeve 2 1st stirring roller 2 2a shaft part 2b screw blade part 2c paddle 3 2nd stirring roller 3a shaft part 3b screw blade part 4 Doctor blade 5 Partition plate 6 Photoreceptor drum 7 Casing 7a 1st developer accommodating part 7b Second developer container 8 Developer 9 Developing device

Claims (6)

[Claims] A developer carrying member for carrying a developer, and a developer transported along the axial direction of the developer carrying member while stirring the developer in a developer container, and a circulation formed between the two. First and second developer stirring and conveying means for circulating the developer in a path, wherein the developer carrier is disposed above the first and second developer stirring and conveying means, The developer carrying member pumps up the developer from the first developer accommodating portion on the side of the first developer agitating / transporting means in the developer container and transports the developer to the developing area. In a two-component developing device having a developer conveyance path configured to be separated into a second developer accommodating portion on the side of the second stirring / conveying means of the developer container, the first developer stirring / conveying means is provided with a first A shaft portion extending in the developer conveying direction along the axial direction of the developer carrier in the developer accommodating portion; A two-component developing device comprising a first developer stirring and conveying member, wherein the shaft diameter of the shaft portion is larger at a portion corresponding to the downstream side than at a portion corresponding to the upstream side in the developer conveying direction. apparatus. 2. The two-component developing device according to claim 1, wherein the shaft diameter of the shaft portion of the first developer stirring and conveying member is gradually increased from upstream to downstream in the developer conveying direction. Component developing device. 3. A developer carrying member for carrying a developer, and a developer transported along the axial direction of the developer carrying member while stirring the developer in a developer container, and a circulation formed between the two. First and second developer stirring and conveying means for circulating the developer in a path, wherein the developer carrier is disposed above the first and second developer stirring and conveying means, The developer on the side of the first developer stirring and conveying means in the developer container is pumped up by the developer carrier and conveyed to the developing area, and the developer after passing through the developing area is further removed from the developer container. In a two-component developing device having a developer conveying path separated to a second stirring / conveying means side, the first developer stirring / conveying means extends in a developer conveying direction along an axial direction of the developer carrier. A first developer stirring / conveying member having a screw therein, and the shaft of the screw A two-component developing device, wherein a pitch in a linear direction is smaller in a downstream region than in an upstream region in a developer conveying direction. 4. The two-component developing device according to claim 3, wherein the pitch of the screw of the first developer stirring and conveying member in the axial direction is gradually reduced from the upstream side to the downstream side in the developer conveying direction. Two-component developing device. 5. A developer carrier for carrying a developer, and a developer transported along the axis of the developer carrier while stirring the developer in a developer container, and a circulation formed between the developer carrier and the developer carrier. First and second developer stirring and conveying means for circulating the developer in a path, wherein the developer carrier is disposed above the first and second developer stirring and conveying means, The developer on the side of the first developer stirring and conveying means in the developer container is pumped up by the developer carrier and conveyed to the developing area, and the developer after passing through the developing area is further removed from the developer container. In a two-component developing device having a developer conveying path separated to a second stirring and conveying means side, the first developer stirring and conveying means is downstream in a developer conveying direction along an axial direction of the developer carrier. Characterized by having a scraping means for scraping the developer upward on the side. Two-component developing device. 6. The two-component developing device according to claim 5, wherein said first developer stirring and conveying means extends in a developer conveying direction along an axial direction of said developer carrier in said developer container. A first developer stirring / transporting member having a shaft portion, wherein the scraping means is provided in a region of the shaft portion on the downstream side in the developer transport direction, and the developer is lifted up by rotation of the shaft portion. A two-component developing device comprising raised blades.