JPH09120201A - Rotating body for stirring developer - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To alleviate and eliminate uneven density without inviting an increase in the number of parts, an increase in cost, an increase in size, and without impairing the functions and capabilities conventionally required. SOLUTION: The shaft member 4 has three or more threads (for example, four or five threads).
(6, 6) spiral blade member 6 has a multi-screw configuration. As a result, the distance between the developer conveying surfaces becomes narrower, the continuity of the developer supply to the developing sleeve is obtained, and the uneven density on the image is alleviated and eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device using a dry two-component developer in a copying machine, a facsimile machine, a printer, etc., and more specifically, a developer stirring rotor for stirring and conveying the developer. Regarding

[0002]

2. Description of the Related Art Generally, an electrophotographic image forming apparatus prints by the following process. That is, as shown in FIG. 8, the surface of the photoconductor drum 1 is uniformly charged by the charger 2, and the photoconductor drum 1 is irradiated with light by the exposure device 3.
To form an electrostatic latent image on the surface of. Next, when the electrostatic latent image passes through a position facing the developing device 4, charged toner adheres to the latent image so that the latent image becomes a visible image, and the latent image is superposed on the recording paper 9 conveyed at a timing. Transfer device 5
Is used to transfer the toner image onto the recording paper 9. The transferred toner image passes through the fixing device 6 so that the recording paper 9
Fixed on top. On the other hand, the latent image charges on the photosensitive drum 1 after the transfer processing are removed by the static eliminator 7, and the residual toner remaining on the photosensitive drum 1 without being transferred is removed by the cleaning device 8. Printing is continuously performed by repeating the above series of processes. In this series of processes, when a dry two-component developer composed of toner and carrier is used in the developing process, the developing device 4 operates as follows.

In the developing device 4 schematically shown in FIG. 8, as shown in FIG. 9, the developer stored in the developing hopper 10 is charged while being stirred by the stirring screw 11, and is supplied to the developing sleeve 12. Form a magnetic brush. While being held by the developing sleeve 12, the magnetic brush passes through the doctor blade 13, which is a developer regulating member, so that the amount and the height of the magnetic brush are regulated. After that, the magnetic brush is conveyed to the developing area 14 where the developing sleeve 12 and the photosensitive drum 1 are formed close to each other, and the toner frictionally charged during stirring or when passing the doctor blade 13 is charged to the opposite polarity. The attracted electrostatic latent image on the photosensitive drum 1 is developed. Toner is consumed by the development,
Toner replenishing device 15 for the developer whose density has become low
Supplies fresh toner. The toner-supplemented developer is agitated by the agitating screw 11 as a rotor for agitating the developer, and is subjected to the next development by repeating the above operation.

By the way, since the toner density of the developer used for development is low, in order to obtain a good image, the developer is successively collected from the developing sleeve, and at the same time, the developer having a sufficient density is obtained. Must be supplied to the developing sleeve one after another, and in a broad sense, all developing devices are configured to circulate the developer. In a broad sense, when the developing device is viewed in cross section, a loop of the developer that travels between the developing sleeve and the developer stirring rotor is called "circulation", as shown by the arrow in FIG. This is the flow of the developer.
On the other hand, the circulation in a narrow sense refers to a case where the developer is conveyed in the longitudinal direction to form a loop, and is a flow of the developer as indicated by an arrow in FIG. 10A. . 10A is a schematic view of the developing device from above, and FIG. 10B is a schematic view of FIG. 10A viewed from the direction of arrow F. Two stirring screws 302 parallel to the developing sleeve 301,
Equipped with these two stirring screws 302, 3
03 is partitioned by a partition plate 304 having both ends cut out, and the developer stored in the developing hopper 305 is agitated by the stirring screw 302,
When 303 rotates, it is conveyed in the arrow direction and circulates. In the case of this configuration, the developing sleeve 30
A circulation as shown in FIG. 9 is also formed between 1 and the stirring screw 302.

The developing device may have a system of circulating the developer in the longitudinal direction as shown in FIG. 10 or a system of not circulating it, but in any case, when the developer having a low density is recovered from the developing sleeve. At the same time, it is necessary to supply a sufficient concentration of developer to the developing sleeve one after another.
In almost all developing devices regardless of the configuration, the stirring screw is arranged in the vicinity of the developing sleeve to form the circulation of the developer as shown in FIG.

Conventionally, a developer stirring rotator rapidly disperses the toner replenished by a toner replenishing device in the developer in order to obtain a good image, thereby promoting frictional electrification of the toner and carrier, and developing. The main purpose is to diffuse the toner so as to eliminate the concentration deviation in the agent. For that purpose, various shapes have been proposed so far. Even when a screw is used as the developer stirring rotor, many are devised to improve the dispersibility of the toner instead of using the normal screw as shown in FIG. For example, as shown in FIG. 11A, the shaft member 3
For example, a bar 308 is attached between the single spiral blades 307 provided in 06, or a fin 309 is attached as shown in FIG. 11B.

[0007]

However, as described above, when the developer stirring rotor is close to the developing sleeve, density unevenness appears in the image depending on the shape of the developer stirring rotor. This is because there is unevenness in the developer supply amount of the developing sleeve.
As shown in FIG. 12A, in the case of a screw shape composed of the shaft member 306 and a single spiral blade 307 provided on the shaft member 306, when the entire black image 310 is taken, as shown in FIG.
As shown in (b), the white line 3 is diagonally arranged at a spiral pitch.
Density unevenness such as 11 is generated. Further, it is known that in the case of a developer stirring rotating body called a paddle in which plates are arranged radially in parallel with the rotation axis, horizontal stripe-shaped density unevenness can occur.

Considering the cause of density unevenness in the rotating member for stirring a developer, which has been known as the most popular shape in the related art, which has the single spiral blade 307 shown in FIG. 12A, it is as follows. . As shown in FIG. 13A, for example, when the developer G is conveyed in the direction of arrow H, the developer G can be roughened before and after the spiral blade 307. That is, since the carrying force is exerted on the developer G on the carrying surface side A of the spiral blade 307, the developer G
Becomes dense, and the developer G becomes coarse on the side B opposite to the transport surface. Therefore, if the developing device has a configuration in which the developer stirring rotor is arranged near the developing sleeve (for example, the configuration in FIG. 10), sufficient developer is supplied to the developing sleeve on the A side of the spiral blade 307. However, the amount of developer that can be supplied to the developing sleeve on the B side is smaller than that on the A side, and
Immediately after the developer on the developing sleeve is collected by the spiral tip, which is the portion closest to the developing sleeve, the developer on the developing sleeve becomes extremely small. FIG.
In 3 (a), reference numeral 312 indicates a casing. As described above, the amount of the developer supplied to the developing sleeve in the spiral lead L becomes uneven, so that it appears as density unevenness on the image, resulting in an abnormal image as shown in FIG. 12B. . In addition, as shown in FIG.
Since the transport surface A of the spiral blade 307 supplies the developer to the developing sleeve only once during rotation, there is no continuity of the developer supply to the developing sleeve, which also contributes to uneven density. It is believed that

Even the improved product with the bar and fins is basically in the shape of a single spiral blade, and therefore still has a problem of uneven image density.

Such density unevenness is alleviated as the developer stirring rotary member is separated from the developing sleeve, but if it is separated too much, the developer collecting ability from the developing sleeve and the developer supplying ability to the developing sleeve are weakened. Therefore, the developer stirring rotor cannot be separated by a distance at which the density unevenness is completely eliminated. In addition, there is also a method of reducing unevenness of the developer supply amount by adding other parts to reduce or eliminate the unevenness on the image, but since it involves an increase in cost and an increase in size,
It is not desirable for recent miniaturization and cost reduction.

Therefore, the present invention can alleviate and eliminate unevenness in density without causing an increase in the number of parts, an increase in cost, and an increase in size, and without impairing the functions and capabilities conventionally required. Providing a rotating body for stirring developer,
With that purpose.

[0012]

The larger the spiral lead, the larger the unevenness of the supply amount. Therefore, the larger the spiral lead, the larger the interval of the image density unevenness. However, if the spiral lead is large,
Since the density of the developer being conveyed changes gently, the density unevenness of the image changes little. From this point of view, by stacking the spiral blades so that the portion immediately after the spiral blades (B side) where the developer supply amount to the developing sleeve is insufficient (B side) is as rough as possible (in other words,
The main goal is to reduce the gap between the developer transport surface of the spiral blade and the transport surface next to it, so that the developer can be continuously supplied to the developing sleeve, and to mitigate or eliminate density unevenness on the image. This is the basic idea of the invention. Specifically, in the invention according to claim 1, for stirring a developer used for a developing device equipped with a developing sleeve and developing with a two-component developer, and for stirring the developer for supplying the developer to the developing sleeve. A rotary body for rotating a developer, comprising a shaft member and a blade member provided on the shaft member, wherein the blade member is formed in a spiral shape and three or more blades are provided. Is adopted.

According to the second aspect of the invention, in the structure of the first aspect, when the twist angle formed by the tangent line at any point on the outer circumference of the blade member and the rotation axis of the shaft member is γ, The configuration is such that the condition of “γ ≦ 75 °” is satisfied. According to a third aspect of the present invention, in the configuration of the first or second aspect, the blade member is divided in the longitudinal direction of the shaft member, and the position of the blade member around the rotation axis is displaced by a predetermined angle on the divided surface. The structure is such that the members are discontinuous. According to a fourth aspect of the present invention, in the structure according to the first or second aspect, when viewed in a cross section perpendicular to the rotation axis, the cutting has a predetermined angle or a predetermined width at an angular cycle of a predetermined interval around the rotation axis. The blade member is discontinuous by providing the notch. According to a fifth aspect of the invention, in the structure of the first or second aspect, the blade member is divided in the longitudinal direction of the shaft member, and the adjacent blade members have portions in which the developer feeding directions are opposite to each other. , Is adopted. In the invention of claim 6, claim 3 or 4 or 5
In the configuration described above, instead of the spiral blade member, a plate fin arranged at an angle corresponding to the twist angle of the blade member is provided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The example shown in FIGS. 1 and 2 corresponds to claim 1, and (a), (b), and (c) of FIG. 2 correspond to (a), (b), and (c) of FIG. 1, respectively. FIG. The developer stirring rotor 2 shown in FIG. 1A is a four-thread screw in which four spiral blade members 6 having spiral leads L ₁ = 56 mm are stacked on a shaft member 4 at an interval of pitch P ₁ = 14 mm. It is configured. The developer stirring rotor 8 shown in FIG. 1 (b) is a five-thread screw in which five spiral blade members 12 with spiral leads L ₂ = 70 mm are stacked on a shaft member 10 at intervals of a pitch P ₂ = 14 mm. It is configured. In the developer stirring rotating body 14 shown in FIG. 1C, the shaft member 16 has a spiral lead L ₃ = 4.
A 2 mm spiral blade member 18 is provided with a pitch P ₃ = 7.
It is configured as a 7-thread screw in which 7 screws are stacked at an interval of mm.

By thus forming the spiral blade member in multiple lines, as shown in FIG. 2, 4, 5, and 6 conveying surfaces A respectively supply the developer to the developing sleeve during one rotation. That is, the supply is continuously performed. Therefore, the variation in the amount of developer supplied to the developing sleeve is reduced, so that the density unevenness on the image can be made very inconspicuous or eliminated.

If the number of spiral blade members is small, the continuity of the developer supply will be poor, so the lower limit is 3 threads. In addition, since the number of spirals increases as the number of threads increases, the continuity of developer supply may increase.
If it is too large, it will be difficult to manufacture, and if the diameter of the rotating body is not so large, the space between adjacent blade members will be narrow and the volume of developer stored will be small. When the leads of each spiral are enlarged in order to widen the blade, the blade member lays down on the rotation axis, which causes disadvantages such as a decrease in the conveying force in the axial direction. Therefore, for example, in the case of a developer stirring rotor having a diameter of around 15 mm, the number of threads is preferably “3 ≦ number of threads ≦ 5”, and in the case of a developer stirring rotor having a diameter of around 25 mm, the number of threads is “4 ≦ thread. The upper limit and the lower limit of the appropriate number of threads vary depending on the diameter, such that “number ≦ 6” is preferable.

Next, FIG. 3 shows an embodiment corresponding to claim 2. The developer stirring rotor 8 shown in this example
Is the five-thread screw structure shown in FIG. As described above, the larger the spiral lead, the larger the pitch of the density unevenness on the image, but the smaller the change in shade. On the contrary, if the spiral lead is small, the density unevenness pitch is also small, but the density is clear, and the density unevenness cannot be eliminated no matter how many blade members are provided. If the change in density is small, it is possible to alleviate or eliminate the density unevenness by ensuring the continuity of the developer supply to the developing sleeve to some extent. Therefore, it is preferable that the spiral lead is large to some extent in order to alleviate and eliminate the uneven density by the multi-thread screw structure.

However, if the screw has the same diameter, the larger the spiral lead, the smaller the change in density, but if the screw has the different diameter, the screw having the smaller diameter has a better degree even with the same spiral lead. That is, the degree of change in shading is not determined by the spiral lead, but by how much the blade member is lying with respect to the rotation axis, in other words, by the twist angle. As shown in FIG. 3, the twist angle γ is an angle formed by the spiral tangent line 20 and the rotation axis line 22 at an arbitrary point on the outer circumference of the blade member 12, and γ [deg] is the screw diameter D
[Mm] and the spiral lead is L [mm], it is calculated by the following formula. Twist angle γ = tan- ¹ {(π × D) / L} In the case of FIG. 3, D = 19 and L = 70, and γ = 40.4.
5 °. Therefore, in order to surely alleviate or eliminate the density unevenness, it is better to let the blade member lie down, and it is better to set the twist angle to at most 75 °. That is, if γ ≦ 75 °, it is possible to more surely reduce the density unevenness, and it is possible to completely eliminate the unevenness by selecting an appropriate number of threads and a twist angle.
As described above, if the twist angle is made too small (the blade member is laid too far), the transporting force in the axial direction will be weakened. Therefore, the screw diameter, rotation speed, developer fluidity, etc. It is preferable to set the helix angle in a range that can secure the required transport amount according to the characteristics. In the embodiment of the present invention, this example has the highest density unevenness eliminating ability.

Next, FIG. 4 shows an embodiment corresponding to claim 3. The developer stirring rotor 24 shown in this example
Is composed of a shaft member 26 and a spiral blade member 28. A four-thread screw having a spiral lead L = 56 mm and a pitch P = 14 mm is 14 mm in the longitudinal direction.
The blade member 28 is divided into spaces, and adjacent blade members 28 on each divided surface are shifted by 45 ° around the rotation axis. The multi-screw screw has a small twist angle, that is, a large number of spiral blade members with a strong conveying force in the rotating direction instead of a relatively weak conveying force in the longitudinal direction are arranged. Compared with the (single screw), the developer is less likely to be conveyed while being accumulated between certain blade members. That is, when the number of threads is large, the developer is transported while being diffused, and therefore the dispersibility of the toner is high, but the dispersibility can be further improved by using the shape as shown in this embodiment. in this way,
If the multi-screw screw as shown in FIG. 1 is divided at equal intervals in the longitudinal direction and the blade members are displaced by a certain angle in the rotational direction before and after the divided surface, it becomes discontinuous.
The developer is vigorously agitated while being conveyed, and the dispersibility of the toner is also enhanced. Therefore, it is possible to alleviate and eliminate density unevenness and obtain high image quality.

Next, FIG. 5 shows an embodiment corresponding to claim 4. The developer stirring rotor 30 shown in this example
As shown in FIG. 5A, is composed of a shaft member 32 and a spiral blade member 34, and each blade member blade 34 of a four-thread screw having a spiral lead L = 56 mm and a pitch P = 14 mm. When viewed in a cross section perpendicular to the rotation axis, 90 cutouts 36 are provided at 90 ° intervals, and the cutouts 36 are alternately arranged so as not to be in the same angular position as the adjacent blade member 34. FIG. 5B is a view obtained by taking out one of the four blade members 34, and the thin line portion is an imaginary line when it is assumed that the cutout portion 36 has a substance. The object of the invention described in claim 4 is claim 3
As in the case of the invention described above, it is intended to enhance the dispersibility of the toner to obtain a high image quality, and the shape as shown in FIG. 5 intends to vigorously stir the developer while conveying it. However, according to the present invention, it is possible to provide continuity in the movement of the developer in the longitudinal direction as compared with the invention described in claim 3, and it becomes possible to carry the developer at a higher speed. Therefore, according to this embodiment,
It is possible to alleviate and eliminate density unevenness, improve image quality by improving toner dispersibility, and transport the developer at high speed. In the invention described in claim 3, since the screw is simply divided at a predetermined interval, the shape of the multi-start screw as shown in FIG. 2 is maintained in an arbitrary cross section. In the invention described in the above, since the multiple lines are not maintained in any cross section, the ability to alleviate / eliminate unevenness in density is higher in the invention described in claim 3, but when high speed conveyance of the developer is required. The present invention is effective for this. Further, in the case of FIG. 4, if the viewpoint is changed, the spiral lead L = 56 mm and the pitch P = 7.
90 mm for each blade member of 8-mm screw
It can also be seen as a special case with a notch of °.

Next, FIG. 6 shows an embodiment corresponding to claim 5. The developer stirring rotor 38 shown in this example
Is roughly composed of a shaft member 40 and a spiral blade member 42, and the spiral lead L = 56 mm,
A spiral-shaped blade member 44 having a length of 7 mm is provided on a four-thread screw having a pitch P of 14 mm at intervals of 35 mm so that the conveying direction is reversed. By doing so, it is possible to perform more vigorous stirring than the inventions according to claims 3 and 4, and it is possible to alleviate and eliminate density unevenness and obtain high image quality. In this embodiment,
The lengths of the spiral blade members in the forward and reverse directions are different, but if both are made the same length, the flow of the developer will not occur, so that the developing device will move the developer near the developing sleeve in the longitudinal direction. It can also be used when it is not configured to be transported to.

Next, FIG. 7 shows an embodiment corresponding to claim 6. The developer stirring rotor 46 shown in this example
Is composed of a shaft member 48 and fins 50 provided in place of the spiral blade member. Fin 50
Is 90 ° when viewed in cross section, as shown in FIG. 7 (b).
It has a plate-like shape and has an inclination of 40 ° with respect to the rotation axis. This is the state in which the spiral lead L = 70 mm and the pitch P = 14 mm of the five-thread screw shown in FIG. 3 are provided with notches of 90 ° at intervals of 90 ° as in the invention of claim 4, and This is the same as replacing the spiral blade member piece with a plate-shaped fin at an angle corresponding to the twist angle (≈40.45 ° [= twist angle of the developer stirring rotor in FIG. 3]). By doing so, some of the functions are sacrificed (such as the conveyance force is reduced and it is difficult to completely eliminate the uneven density), but the uneven density and high image quality are alleviated, and at the same time, the manufacturing is easy, and This is effective when the cost can be reduced and a lower cost is required.

The present invention can be said to be a modification of the single screw as shown in FIG. 12 (a), and is premised on the case where the developer stirring rotary member near the developing sleeve needs the function of carrying in one direction. . When the developer stirring rotator near the developing sleeve has a unidirectional transport function, the developing device is generally configured to circulate in the longitudinal direction as shown in FIG. In many cases, the present invention can be applied to other cases where the developer stirring rotor near the developing sleeve is required to have a one-way conveyance function.
The configuration is not limited to the above.

[0024]

As described above, according to the first aspect of the invention, since the multi-screw structure in which the spiral blade member is provided with three or more threads is provided, continuity of the developer supply to the developing sleeve is obtained. Therefore, without increasing the number of parts, increasing the cost, and increasing the size, and
The density unevenness on the image can be alleviated or eliminated without impairing the required function. According to the invention described in claim 2, since the spiral-shaped blade member has a smaller twist angle, the conveying force in the longitudinal direction becomes stronger instead of the conveying force in the longitudinal direction being weaker, so that the developer moves faster in the longitudinal direction. Since the toner is replenished while being spread, the dispersibility of the replenished toner is fast, and when the developer concentration deviation in the longitudinal direction in the developing hopper becomes large, the overall developer concentration becomes uniform. In addition, by making the helix angle smaller than before, the conveying force in the axial direction of one spiral blade member becomes weaker and the conveying amount becomes smaller, but it is compensated for by the large number of threads, so rotation The whole body has a stronger carrying force than the conventional one, and the carrying amount is very large. According to the third aspect of the present invention, the spiral blade member is discontinuous, so that the developer can be vigorously agitated, so that the dispersibility of the toner can be improved and high image quality can be obtained. it can. Although the spiral blade member is discontinuous, since the same shape as that of the first and second aspects is maintained in the cross section perpendicular to the axis, it is possible to alleviate / eliminate the uneven density. According to the invention described in claim 4, each spiral blade member is discontinuous, and the same shape as that of claims 1 and 2 is maintained in an arbitrary cross section perpendicular to the axis. Not so
Although the ability to alleviate / eliminate unevenness in density is inferior to that of the third aspect, the developer is vigorously stirred because it is discontinuous, the toner dispersion is improved, and high image quality is obtained. The developer flow is more continuous and excellent in high-speed conveyance than that of the item 3. According to the invention described in claim 5, since the spiral blade member for sending the developer in the reverse direction is arranged in part, the developer can be vigorously agitated, so that higher image quality can be obtained. be able to. According to the sixth aspect of the invention, since the plate-shaped fins that are easy to manufacture are provided instead of the spiral blade members, it is effective when a lower cost is required.

[Brief description of the drawings]

FIG. 1 is a side view of a rotary member for stirring a developer showing an embodiment of the present invention, in which (a) is a spiral blade member having four rows, and (b) is five rows. c) is a side view showing each of the six articles.

2A and 2B are schematic cross-sectional views of the developer stirring rotating body shown in FIG. 1, in which FIG. 2A is shown in FIG. 1A, FIG. 2B is shown in FIG.
(C) is a figure corresponding to FIG.1 (c), respectively.

FIG. 3 is a side view of a developer stirring rotary body corresponding to claim 2;

FIG. 4 is a side view of a developer stirring rotating body corresponding to claim 3;

5A and 5B are views showing a rotating body for stirring a developer according to claim 4, wherein FIG. 5A is a side view of the whole, and FIG. 5B is one spiral blade shown as a substance in a cutout portion. It is a figure of a member.

FIG. 6 is a side view of a developer stirring rotor according to a fifth aspect of the present invention.

7A and 7B are diagrams showing a developer stirring rotating body corresponding to claim 6, wherein FIG. 7A is an overall side view and FIG. 7B is a schematic sectional view.

FIG. 8 is a schematic diagram for explaining an image forming process of the image forming apparatus.

FIG. 9 is a schematic sectional view of a developing device in the image forming apparatus.

FIG. 10 is a diagram showing circulation of a developer in a developing device,
(A) is a plan view, (b) is a schematic sectional view seen from the arrow F side of (a).

FIG. 11 is a view showing a conventional rotating body for stirring a developer,
(A) is a side view of an example in which a bar is provided between spiral blade members, and (b) is a side view of an example in which fins are arranged between spiral blade members.

FIG. 12 is a diagram for explaining density unevenness in a conventional product,
FIG. 7A is a side view of a conventional single-member type rotary member for stirring a developer, and FIG. 8B is a schematic view showing density unevenness on an image.

13A and 13B are diagrams showing a state where a developer is conveyed in a conventional product, in which FIG. 13A is a side view and FIG. 13B is a schematic sectional view.

[Explanation of symbols]

 4,10,16,26,32,40,48 Shaft member 6,12,18,28,34,42,44 Blade member 20 Tangent line 22 Rotation axis line 36 Notch 50 Fin γ Twist angle

Claims (6)

[Claims] 1. A developer stirring rotor for stirring a developer and supplying the developer to the developing sleeve, which is used in a developing device equipped with a developing sleeve for developing with a two-component developer, comprising a shaft member. And a blade member provided on the shaft member for stirring a developer, wherein the blade member is formed in a spiral shape and three or more blades are provided. Rotating body. 2. When the twist angle formed by the tangent line at an arbitrary point on the outer circumference of the blade member and the rotation axis of the shaft member is γ, the condition "γ≤75 °" is satisfied. The developer stirring rotor according to claim 1. 3. The blade member is divided in the longitudinal direction of the shaft member, and the position of the blade member around the rotation axis is displaced by a predetermined angle on the dividing surface so that the blade member is discontinuous. The developer stirring rotor according to claim 1. 4. The blade member becomes discontinuous by providing notches that have a predetermined angle or a predetermined width at an angular cycle of a predetermined interval around the rotation axis when viewed in a cross section perpendicular to the rotation axis. Claim 1 or 2 characterized in that
The rotating body for stirring the developer as described. 5. The developing device according to claim 1, wherein the blade member is divided in the longitudinal direction of the shaft member, and adjacent blade members have portions in which the developer feeding directions are opposite to each other. Rotating body for stirring agents. 6. Instead of the spiral blade member,
6. The developer stirring rotator according to claim 3, further comprising plate-shaped fins arranged at an angle corresponding to the twist angle of the blade member.