JP2530610Y2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dry-type developing apparatus using a powder developer.

[Conventional technology]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a facsimile, a printer, or the like, a dry-type developing device is widely used as a type in which an electrostatic latent image is formed on a latent image carrier and is visualized.

FIGS. 4 and 5 show a conventional example, in which a unitized developing device 101 includes a developing container 102 containing a two-component developer D having a toner and a carrier, and one configuration of a developer carrying member. The image forming apparatus includes a sleeve-shaped developing roller 105 as an example, a plurality of magnets 106 provided in the developing roller 105, and a paddle roller 104 as an example of a developer stirring and pumping rotary member. The paddle roller 104 includes shafts 122 and 123 and the bearing 11
It is rotatably supported on each side plate 102a, 102b of the developing container 102 via 1. The developer D in the developing container 102 is pumped up while being stirred by the counterclockwise rotation of the paddle roller 104 and supplied to the developing roller 105. The paddle roller 104 has a large number of radially extending stirring and pumping blades 1.
Has 20.

On the other hand, the developing roller 105 also has a shaft and a bearing 112,
The developer D supplied to the developing roller 105 is rotatably supported by the respective side plates 102a and 102b of the developing container 102, and the developer D supplied to the developing roller 105 is rotated by the relative rotation of the developing roller 105 or the magnet 106 or both. It is transported while being carried. Magnet 106
Is used to carry the developer on the peripheral surface of the developing roller 105 by magnetic force. In this example, the magnet 106 is held in a non-rotating state, the developing roller 105 is driven to rotate in the direction of the arrow shown in the figure, and the carried developer is conveyed in the same direction.

The developer carried and carried by the developing roller 105 is scraped off at a doctor blade 107, and is regulated to a fixed amount. The regulated developer is transported while being continuously carried on the developing roller 105, and is conveyed by the magnet 1
When it is transported to the vicinity of the main pole Pm of 06, it becomes brush-like due to the magnetic force of the main pole Pm.

On the other hand, a drum-shaped photoconductor 150, which is an example of a latent image carrier, is opposed to the developing roller 105 with a slight gap, and is driven to rotate in the direction of the arrow. An electrostatic latent image is formed on the surface of the photoconductor 150 by a latent image forming unit (not shown).

The photoreceptor 150 passes through the magnetic brush of the developer formed by the main pole Pm as described above, i.e., passes through the development area, and at this time, the brush is rubbed against the electrostatic latent image on the photoreceptor 150 to form a brush. The toner in the developing agent electrostatically transfers to the electrostatic latent image, and the electrostatic latent image is developed and visualized. As described above, the developing roller 105 is used to develop the electrostatic latent image formed on the photoreceptor 150 with the developer carried and transported by the developing roller 105.

The developer on the developing roller 105 that has passed through the developing area is returned to the developing container 102 again. Also, doctor blade 107
The developer scraped off at this point is guided toward the current plate 108 and returns to the paddle roller 104 through this portion.

When the toner concentration of the developer D in the developing container 102 decreases, the toner supply roller 109 rotates, and the toner hopper 110
Toner T falls into the developing container 102, and the paddle roller 1
04 is mixed into the developer D by stirring.

In such a developing device, each side plate 102a,
The developer may overflow from the gap between the photoconductor 150 and the photoconductor 150, or the developer may enter the bearing 111 of the paddle roller 104 to lock the shaft. This will be described in detail with reference to FIG.

FIG. 5 is an explanatory plan view schematically showing the positional relationship between each element of the developing device 101 and the photoconductor 150. As shown in FIG. 5, a magnet 106 provided inside the developing roller 105 is The overall length is set shorter than the developing roller 105, and the overall length of the paddle roller 104 is equal to the length of both side plates 102a, 102b of the developing container 102.
It is set shorter than the distance between. Paddle roller
Between each end face of 104 and each side plate 102a, 102b, for example, 10 mm
Gap G2 is formed. Also, between each end face in the longitudinal direction of the developing roller 105 and each side plate 102a, 102b, usually,
For example, gaps G1 of about 1 mm are respectively formed.

Here, for example, the axial length W1 of the effective image forming area of the photoreceptor 150 is 420 mm, the length W2 of the magnet 106 in the developing roller 105 is 440 mm, and the distance W3 between the front and rear side plates 102a and 102b of the developing container 102. Is set to 460 mm, and the total length W4 of the developing roller 105 is set to 458 mm, the magnetic force between each end in the longitudinal direction of the magnet 106 and each side plate 102a, 102b is weak, or the magnetic force is substantially If the developer is supplied to the peripheral surface of the developing roller 105 corresponding to this portion by the paddle roller 104, the developer supplied to the peripheral surface of the developing roller cannot be held by the magnetic force and cannot be transported. Will be. Therefore, the total length W of the paddle roller 104
5 is set to, for example, about 440 mm, which is substantially equal to the total length W2 of the magnet 106, so that the developer is supplied only to the peripheral surface of the developing roller 105 to which the magnetic force of the magnet 106 reaches. For this reason, the total length W5 of the paddle roller 104 is set to be shorter than the distance between the side plates 102a and 102b, and thereby, between each end thereof and each of the side plates 102a and 102b, for example, 10 mm Gap of G2
Can be done respectively.

By the paddle roller 104 having the form as exemplified above,
The developer is supplied to the peripheral surface of the developing roller 105 corresponding to the length W2 of the magnet 106, and returns to the developing container 102 after passing through the developing area shown in FIG. A part of the developer returned in this way is supplied to the end of the paddle roller 104 and the side plates 102a, 102a.
It enters the gap G2 between 2b. At this time, since the developer entering here is not substantially subjected to the transporting action, the developer stays here. Then, the amount of the developer gradually increases, and when this developer accumulates in the region of each end of the developing roller 105, the magnet 106 does not exist at the end of the developing roller, and the developer is retained here. Since the magnetic force is not applied, the developer overflows from the opening of the developing container 102 facing the photoconductor 150 (FIG. 4) (see the arrow X in FIG. 4).

When the developer accumulates in the gap G2, the developer is
4 enters the bearing 111, and the shafts 122 and 123 of the paddle roller 104
Can cause the lock.

[Problem to be solved by the present invention] An object of the present invention is to provide a developing device which solves the above-mentioned drawbacks at once.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a developing container containing a developer, and is supported by each side plate of the developing container.
A developer carrying member that carries and transports the developer on the peripheral surface and develops the electrostatic latent image formed on the latent image carrier with the transported developer; A magnet for supporting the developer by a magnetic force on a peripheral surface of the developer carrying member, and a rotatable support via a shaft on each side plate of the developing container, and pumping up the developer in the developing container while stirring the developer. A developer stirring and pumping rotary member to be supplied to the supporting member, wherein the magnet provided inside the developer supporting member has a total length shorter than that of the developer supporting member, and a developer stirring and pumping rotary member. In a developing device in which the total length of the developing container is set to be shorter than the distance between both side plates of the developing container, on a surface of the disk portion provided at both ends of the developer stirring and pumping rotary member facing the developing container side plate, Standing almost perpendicular to the surface, Extends in a radial direction of the developer stirring scooping rotational member, proposes a developing apparatus is characterized in that a fin which is located with a gap relative to the axis of the developer stirring scooping rotational member.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a unitized developing device, 2 denotes a developing container containing a two-component developer D, 2a and 2b denote front and rear side plates of the developing container 2, and 5 denotes a developer. A developing roller as an example of a supporting member, 6 is a magnet, 7 is a doctor blade, 8 is a rectifying plate, 9 is a toner supply roller, 10 is a toner hopper containing toner T, 12 is a bearing for the developing roller, and 50 is a latent image. Drum-shaped photoreceptors as an example of a configuration of an image carrier are shown, and these are a conventional developing device 101, a developing container 102, side plates 102a and 102b, a developing roller 105, and a developing device 101 shown in FIGS. 4 and 5. Magnet 106, doctor blade 107, current plate 10
8, corresponding to the toner supply roller 109, the toner hopper 110, and the photoconductor 150, respectively.

Reference numeral 4 denotes a paddle roller corresponding to the paddle roller 104 of the conventional developing device shown in FIG.
This constitutes an example of a rotating member for pumping and stirring the developer. As shown in FIG. 3, the paddle roller 4 also has a large number of agent stirring and pumping blades 20 arranged in the hollow cylindrical portion 21 at equal pitches in the circumferential direction.
The developer D in the developing container 2 is pumped up with stirring and supplied to the developing roller 5 by the counterclockwise rotation of. The paddle roller 4 is rotatably supported by the side plates 2a and 2b of the developing container 2 via shafts 22 and 23 and bearings 11 and 11 at each end thereof.

The other configuration and operation of the developing device 1 described above are the same as those of the conventional developing device shown in FIGS. 4 and 5, and the positional relationship of each member is also the same as that of FIG. Therefore, further description of the developing device 1 will be omitted.

What is different from the conventional developing device is that disc portions 13, 13 are fixed to both ends of the paddle roller 4, and these disc portions 13, 13 are fixed.
On the surface facing the developer container side plates 2a and 2b, an appropriate number of fins 15 are provided at substantially regular intervals and are provided substantially at right angles to the surface and extending in the radial direction of the paddle roller 4. It is. The fins 15 provided on each of the disk portions 13, 13 are located with a gap from the shafts 22, 23 of the paddle roller 4. Each fin 15 does not hit the shaft 22, 23,
It is far from 23.

In FIG. 1, when the paddle roller 4 for supplying the developer to the developing roller 5 is driven to rotate together with the developing roller 5, the fins 15 also rotate together therewith. By such a developing operation, the developer enters the gap G2 between each end of the paddle roller 4 and each of the side plates 2a and 2b as described earlier with reference to FIG. The developer is fed by the rotating fins 15 in a direction away from the developing roller 5, that is, in a direction indicated by an arrow A in FIG.

At this time, each fin 15 extends in the radial direction of the paddle roller 4 and is separated from the shafts 22 and 23. Since there is a gap between the fin 15 and the shafts 22 and 23, the fins 15 are fed away from the developing roller 5. The supplied developer can be prevented from being fed back to the developing roller 5 again. Assuming each fin 15 is an axis
If it extended to the point where it touches 22,23,
The developer sent in the direction of arrow A is constrained by the fins and is sent again toward the developing roller 5 and enters the gap G2, which may cause the same problem as in the related art. Such a problem can be prevented from occurring.

Thus, each end of the paddle roller 4 and each side plate 2
The developer does not accumulate in the gap G2 between the a and 2b, and accordingly, the developer existing at each end of the developing roller 5 also smoothly goes to the inside of the developing container (to the right in FIG. 1). And the developer is prevented from accumulating at each end of the developing roller 5.

As described above, it is possible to prevent the problem that the developer overflows from the opening of the developing container or that the developer is clogged in the bearing 11 of the paddle roller 4, thereby preventing bearing lock from occurring.
Note that the tip of the fin 15 may be brought into contact with each side plate 2a, 2b of the developing container 2, but in this case, the paddle roller 4
Fin 15 and side plates 2a, 2b
It is desirable that the fins 15 are slightly separated from each other so that the function of delivering the developer by the fins 15 is not hindered.

The present invention is applicable to a developing device using a one-component developer as well as a developing device using a two-component developer.

[Effect of the invention]

According to the present invention, it is possible to eliminate the problem that the developer overflows from the opening of the developing container to the outside or the developer is agitated and pumped up, and the bearing of the rotating member is clogged with the developer to cause a bearing lock.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a developing device according to an embodiment of the present invention.
FIG. 2 is an explanatory plan view illustrating the arrangement of each element of the developing device, FIG. 3 is a perspective view showing a paddle roller, a disk portion and fins attached thereto, and FIG. 4 is an example of a conventional developing device. FIG. 5 is a conventional explanatory diagram, and FIG. 2 is a similar explanatory diagram. DESCRIPTION OF SYMBOLS 1 ... Developing device, 2 ... Developing container 2a, 2b ... Side plate, 6 ... Magnet 13 ... Disc part, 15 ... Fin 22, 23 ... Shaft, D ... Developer

Claims (1)

(57) [Scope of request for utility model registration] 1. A developing container for storing a developer, supported on each side plate of the developing container, carrying and transporting the developer on the peripheral surface, and forming the latent image carrier with the transported developer. A developer carrying member for developing the electrostatic latent image, a magnet provided inside the developer carrying member and carrying the developer by a magnetic force on a peripheral surface of the developer carrying member, and a side plate of the developing container. A developer agitating and rotating member rotatably supported via a shaft, and agitating and pumping up the developer in the developer container to supply the developer to the developer carrying member; In the developing device, the length of the magnet is set shorter than the developer carrying member, and the total length of the developer stirring and pumping rotary member is set shorter than the distance between both side plates of the developing container. It is provided at both ends of the stirring pumping rotary member. The surface of the disc portion facing the developer container side plate is provided substantially upright with respect to the surface, extends in the radial direction of the developer stirring and pumping rotary member, and is provided with the developer stirring and pumping rotary member. A developing device comprising a fin positioned with a gap from an axis.