JPH07181787A - Developing device for image forming device - Google Patents

Abstract

PURPOSE:To make the quantity of developer carried in the elliptic plate region of the end part of a stirring paddle sufficient and to prevent the failure of the occurrence of a void in an image and irregularities in the density by providing ribs at least on a part of the stirring paddle. CONSTITUTION:The stirring paddle 20 is provided with plural elliptic plates 22 attached onto a shaft 21 at a constant inclined angle. Plate-like ribs 23a and 23b are provided in contact with the shaft 21 and respective elliptic plates 22a and 22b outside them on both end parts. Respective plate-like ribs 23a and 23b are extended in the radial direction from the shaft 21 so that the directions of the ribs 23a and 23b is opposed to each other. Thus, in the stirring paddle 20, its carrying force in the vertical direction is improved especially on both end parts of the stirring paddle 20 compared with that on other parts by both plate-like ribs 23a and 23b in addition to a stirring action in the horizontal direction by each elliptic plate 22. The stirring paddle provided with plural inclined elliptic plates 22a and 22b is illustrated here but the above-mentioned manner is applied not only to this stirring paddle but also a screw type stirring paddle.

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 printer or a facsimile machine, which is provided with a stirring paddle for laterally stirring a developer mainly composed of two components in a developing container. The present invention relates to a developing device for visualizing the formed electrostatic latent image.

[0002]

2. Description of the Related Art Of the two-component developers consisting of toner and carrier, it is the toner that actually contributes to the development. Therefore, if the development work is continued, the amount of toner decreases, so that the toner is always replenished. become. A stirring paddle is usually installed in the developing container for charging the newly replenished toner and for mixing and dispersing with the existing developer. A conventional developing device equipped with such a stirring paddle will be described with reference to FIGS.

In FIG. 6, a developing device 2 is arranged around the photosensitive drum 1 as one of process units. The developing device 2 includes a developing container 3 that stores a two-component developer.
And a toner cartridge 4 for supplying toner to the developing container 3. In the developing container 3, a developing roller 5 which is arranged close to the photosensitive drum 1 and rotates in the forward direction with the photosensitive drum 1, a doctor 6 which regulates the developer on the developing roller 5, and a developer is supplied to the developing roller 5. An agitating roller 7, an agitating paddle 8 described later, a replenishing roller 9, a separator 10 arranged to face the developing roller 5, and the like are provided.

When the toner density in the developing container 3 becomes low,
The toner replenishing roller 9 rotates according to a replenishing signal from a sensor (not shown), and the toner in the toner cartridge portion 4 enters the developing container 3 and mixes with the developer already in the developing container 3. Developing roller 5, stirring roller 7, stirring paddle 8
Rotates in the direction of the arrow shown. The newly replenished toner is stirred and charged by the stirring paddle 8, is mixed and dispersed with the developer already in the developing container, and is then sent to the developing roller 5 by the stirring roller 7.

A conventional stirring paddle is shown in FIG.
As shown in (4), it was mainly composed of a plurality of elliptical plates 11 mounted on the shaft 12 at a constant inclination angle. Due to its main purpose, the stirring paddle 8 having this configuration has insufficient vertical conveying ability as compared with the horizontal stirring ability.

This will be explained with reference to the drawings. The stirring paddle 8
Performs one rotation operation as shown in a, b, c, d of FIG. In that case, the stirring paddle 8 stirs the developer in the horizontal direction shown in FIG. 9A, but the vertical conveyance shown in B is not sufficient.
There is a drawback that the delivery of the developer to the toner is weak, and this drawback is particularly remarkable at the end of the stirring paddle 8.

[0007]

Due to the above-mentioned drawbacks of conventional stirring paddles, the image forming apparatus is not installed in a horizontal place, and thus when the developing device is inclined in its longitudinal direction,
The amount of the transported developer in the elliptical plate area at the end of the stirring paddle was reduced, and as a result, defects such as missing spots and uneven density on the image were unavoidable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device which solves the above-mentioned problems in the conventional developing device and which can sufficiently convey the developer in the vertical direction.

[0009]

SUMMARY OF THE INVENTION The above problems are solved according to the invention by providing ribs on at least a portion of the stirring paddle.

In order to solve the above-mentioned problems, the present invention proposes that ribs are provided only at both ends in the longitudinal direction of the stirring paddle.

In order to solve the above-mentioned problems, the present invention provides that the ribs provided at both longitudinal ends of the stirring paddle have a larger radial length than the ribs provided at other portions. To propose.

Further, in order to solve the above problems, the present invention proposes that the number of ribs provided at both longitudinal end portions of the stirring paddle is larger than the number of ribs provided at other portions. .

[0013]

In the stirring paddle for laterally stirring the developer, ribs having a large vertical conveying force are provided at both ends in the longitudinal direction thereof, so that the insufficient conveying capacity of the stirring paddle is solved. It is also possible to provide ribs over the entire length of the stirring paddle,
In this case, ribs having a large radial distance are provided at both ends in the longitudinal direction, or the number of ribs provided is increased. As a result, the vertical conveying force of the stirring paddle, particularly the longitudinal conveying force at both ends in the longitudinal direction thereof, is enhanced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the stirring paddle 20 includes a shaft 21.
It has a plurality of elliptical plates 22 mounted on it with a certain inclination angle. Outside the elliptical plates 22a and 22b at both ends, plate-like ribs 23a and 23b are provided on the shaft 21 and the elliptical plates 22 respectively.
It is provided in contact with a and 22b. Each plate-shaped rib 23
The a and 23b extend from the shaft 21 in opposite directions in the radial direction.

With the above-described structure, the stirring paddle 20 has a lateral stirring action by each elliptical plate 22, and the plate-shaped ribs 23a and 23b allow the stirring paddle 20 to be conveyed vertically in particular. The power is improved more than other parts.

The stirring paddle 30 shown in FIG. 2 comprises a plurality of elliptical plates 32 mounted on a shaft 31 at a constant inclination angle. Ribs 33 extending on both sides in the diametrical direction from the shaft 31 are provided between the respective elliptical plates 32, and these ribs 3 are provided.
The heights of the shafts 31 at both free ends in the radial direction of 3 from the shaft center are the same, and are H ₁ .

Elliptical plates 3 at both ends of the stirring paddle 30
On the outside of 2a, 32b, another rib 33a, 33b extending on both sides in the diametrical direction from the shaft 31 is provided with elliptical plates 32a, 32b.
It is provided in contact with. These ribs 33a, 33b
Has the same height between both free ends in the radial direction and the axis of the shaft 31, and is larger than the height H ₁ by H _{2 respectively.}
Is.

With the above-described structure, the stirring paddle 30 shown in FIG. 2 has a stirring action in the horizontal direction and a conveying force in the vertical direction over the entire length thereof, and in particular, at both ends of the stirring paddle 20, the stirring paddle 20 is conveyed in the vertical direction. The power is improved more than other parts.

The stirring paddle 40 shown in FIG. 3 comprises a plurality of elliptical plates 42 mounted on a shaft 41 at a constant inclination angle. The elliptical plates 4 between and at both ends of each elliptical plate 42
Ribs 43 extending through the shaft 41 on both sides in the diametrical direction are provided through the outside of the shafts 2a and 42b. As shown in FIG. 4, the height of the free end of the rib 43 in the radial direction from the axis of the shaft 41 is the same on both sides in the diametrical direction.

Further, in addition to the rib 43, another rib 44 which is perpendicular to the rib 43 is provided on the outer side in the axial direction of the elliptical plates 42a and 42b. As shown in FIG. 5, the height from the shaft center of the shaft 41 to both free ends of the rib 44 is the same, and is lower than the height of the rib 43. This allows
At both ends of the stirring paddle 40, the conveying force in the vertical direction is improved as compared with other portions. It is also possible to provide an arbitrary plurality of ribs 44 at an appropriate angle.

Although the embodiments of the stirring paddle provided with a plurality of inclined elliptical plates have been described above, the present invention is not limited to this, and can be applied to a screw type stirring paddle.

[0023]

【The invention's effect】 [Brief description of drawings]

FIG. 1 is a front view of a stirring paddle constructed according to the present invention.

FIG. 2 is a front view of another embodiment of a stirring paddle according to the present invention.

FIG. 3 is a front view of a stirring paddle of still another embodiment.

4 is a sectional view taken along the line IV-IV in FIG.

5 is an end view as seen in the direction VV of FIG.

FIG. 6 is a cross-sectional view of a developing device.

FIG. 7 is a perspective view of a conventional stirring paddle.

8 is an explanatory view of an operating mode of the conventional stirring paddle shown in FIG. 7. FIG.

9 is a functional explanatory diagram of the developing device shown in FIG.

[Explanation of symbols]

1 Photoreceptor Drum 2 Developing Device 8; 20; 30; 40 Stirring Paddle 23a, 23b; 33, 33a, 33b; 43, 44
rib

Claims (4)

[Claims] 1. A developing device of an image forming apparatus for visualizing an electrostatic latent image formed on a photoreceptor, comprising a stirring paddle for laterally stirring a developer in a developing container. A developing device, wherein at least a part of the paddle is provided with a rib. 2. The developing device according to claim 1, wherein ribs are provided only at both ends of the stirring paddle in the longitudinal direction. 3. The developing device according to claim 1, wherein ribs provided at both ends of the stirring paddle in the longitudinal direction have a radial length larger than that of ribs provided at other portions. apparatus. 4. The number of ribs provided at both ends in the longitudinal direction of the stirring paddle is larger than the number of ribs provided at other portions, according to claim 1 or 3. Development device.