JPH0455327Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a developing device that uses a two-component developer, and more specifically, to a developing device that makes the circulation of the developer in the developing device more efficient. Regarding equipment.

(Prior Art) In recent years, with the spread of copying machines, there has been a demand for high quality and stable copied images.

In response to these demands, a so-called forward development system has been proposed in which a two-component developer consisting of toner and carrier is used and the photoreceptor and magnetic brush move in the same direction in the development area.

(Problem to be solved by the invention) However, compared to the conventionally used reverse development system, this forward development system requires a developer pumping mechanism, making the device larger. The problem is that it is very difficult to form an efficient developer circulation loop. This results in partial retention of the developer. In addition, when placing importance on image stability, it is essential to stir the developer in the developing device in the width direction of the developing device.

(Purpose of the invention) The present invention relates to an improvement of a developing device that employs a forward development system, and its purpose is to provide a developing device that can efficiently circulate developer within the developing device. There is a particular thing.

Another object of the present invention is to provide a developing device that can efficiently stir the developer in the width direction of the developing device.

(Structure of the invention) According to the invention, in order to achieve the above object,
A hopper equipped with a toner supply roller, a developer conveying sleeve that rotates in a direction opposite to the rotational direction of the photosensitive drum and has a magnet inside, and a magnetic brush tip formed on the developer conveying sleeve. A spike plate for regulating the length, and a plurality of stirring blades provided close to the developer conveying sleeve and having tips bent in the direction of rotation are provided radially around the outer periphery, and each of the stirring blades has a A stirring roller having a spiral passage formed in the axial direction of its outer periphery by a notch provided and a guide portion provided by bending one end of the notch, and an upper part of the stirring roller. and has a plurality of guide plates on at least one of the front and back sides at predetermined intervals and oriented in a direction forming an acute angle or an obtuse angle with the axial direction of the agitation roller, and the movement of the developer in the axial direction is controlled by the agitation roller. A developer flow regulating plate that regulates the flow in a direction opposite to the direction of movement by the stirring roller, and a developer flow regulating plate that is located upstream in the direction of rotation of the sleeve from the position closest to the sleeve and the stirring roller, and Accordingly, there is provided an electrophotographic developing device comprising a transfer roller that scrapes the magnetic brush on the surface of the sleeve and conveys the developer in one longitudinal direction.

(Example) Examples of the present invention will be described in detail below using the accompanying drawings.

FIG. 1 shows a sectional view of a developing device of the present invention employing a forward developing system.

A developing device, generally designated by 3, is provided opposite to a photosensitive drum 2 rotating in the direction of arrow 1. As shown in FIG.
A nonmagnetic cylindrical sleeve 5 that rotates in the direction of arrow 4 is provided at the opening of the housing 3' of the developing device 3 on the photosensitive drum 2 side. This sleeve 5 has a built-in magnet 6, which has a plurality of magnetic poles on its surface and does not rotate itself, and constitutes a developing sleeve. A magnetic brush 9 of a two-component developer consisting of toner and carrier is formed on the surface of this developing sleeve, and as the sleeve 5 rotates in the direction of the arrow 4, this magnetic brush 9 is transferred to the photoreceptor. The drum 2 is rubbed against the developing area A.

Further, a developer stirring roller 8 having a plurality of stirring blades 7 is provided close to the sleeve 5 on the opposite side of the photosensitive drum 2 .

This stirring roller 8 rotates in the same direction as the sleeve 5, and forms a developer supply region B that supplies developer to the surface of the sleeve 5 in the region where the sleeve 5 and the stirring roller 8 are closest to each other.

Furthermore, a developer flow regulating plate 10 for forming a developer circulation path is provided above the stirring roller 8 , and a magnetic brush 9 formed on the sleeve 5 is provided above the sleeve 5 . A panicle cutting plate 11 is provided for regulating the grain size. Further, a hopper section 15 having a toner supply roller 14 is disposed above the developing device 3 .

Here, to explain the flow of the developer, the developer supplied from the stirring roller 8 to the sleeve 5 in the above-mentioned area B is gradually compressed according to the angle formed between the lower surface 10a of the regulating plate 10 and the curved surface of the sleeve 5. be done. The compressed developer is made into predetermined spikes by a spike cutting plate 11. The remaining developer at this time is carried along the slope of the upper surface of the regulating plate 10 and returned to the stirring roller 8, where it is stirred and mixed again and supplied to the sleeve surface.

On the other hand, after cutting the ears, the magnetic brush 9 of the developer on the sleeve 5 comes into contact with the area A of the photosensitive drum 2 and contributes to development. As the sleeve 5 rotates, the magnetic brush 9 after development is carried to the non-magnetized region 6' of the magnet 6, and is separated from the surface of the sleeve 5.

However, when considering miniaturization of the developing device, even if it is possible to miniaturize the sleeve, there is a limit to weakening the magnetic force for holding the developer on the surface of the sleeve 5, so the non-magnetized portion 6'
It must be difficult to form a If it becomes difficult to remove the developer from the sleeve 5 in this way, spent toner will be generated on the sleeve surface, which will have an adverse effect on development.

In the present invention, in order to promote the separation of the developer, a transfer roller is provided as a transfer roller on the upstream side in the rotational direction of the sleeve 5 from the developer separation area 6', that is, the closest position between the sleeve 5 and the stirring roller 8. A spiral roller 12 is provided to rotate in the same direction as the sleeve 5. As shown in FIG. 2, the spiral roller 12 has spiral blades 21 formed in a counterclockwise direction with respect to a central axis 20. The blades 21 can scrape off the developer on the sleeve 5 and facilitate conveyance to the stirring roller 8 . At the same time, the two magnetic poles on both sides of the region 6' in the magnet 6 are of the same polarity, so that a repulsive magnetic field is always formed in the region 6'. With these configurations, the developer on the sleeve 5 after development can be efficiently removed from the sleeve without remaining on the sleeve 5. Furthermore, the detached developer is removed from the roller 1.
2, the movement to the stirring roller 8 is performed smoothly.

The stirring roller 8 is conveyed while being stirred by a conveying section 13 formed between the stirring blades, and is again supplied to the sleeve 5.

In the present invention, while efficiently circulating the developer as described above, the stirring roller 8, the developer flow regulating plate 10, and the spiral roller 12 are used to circulate the developer in the longitudinal direction (width direction) of the developer device. ).

FIG. 2 is a perspective view showing the arrangement of the stirring roller 8, the regulating plate 10, and the spiral roller 12 in the developing device of the present invention.

The stirring roller 8 has a shape in which the distal end portion 24 of the stirring blade 7 is bent in the direction of rotation, and further has a plurality of notches 31 formed therein. One end of the cutout 31 is bent in one direction to form a guide 32, which allows the developer to move between adjacent developer transport spaces 13. . A plurality of guide portions 32 are provided on each stirring blade 7, and the developer can be conveyed in the direction of an arrow 34 by rotation of the stirring roller 8 (counterclockwise in FIG. 2). The guide portions 32 are arranged so that all the directions in which they are bent are in the same direction, and furthermore, in order to improve the ability to convey the developer in the width direction by the rotation of the agitation roller 8, the guide portions 32 are arranged so that the directions in which they are bent are all in the same direction. By shifting the guide portions 32 of adjacent stirring blades 7 at regular intervals in the longitudinal direction, a spiral passage is formed in the axial direction of the outer periphery of the stirring roller 8.

By configuring the stirring roller in this way, the developer that is regulated by the cutting plate and flows back, the replenishment toner that is replenished from the hopper, the developer that has been scraped off from the developing sleeve, and the developer that is inside the developing device. It becomes possible to move it in one longitudinal direction (width direction) while efficiently mixing and stirring the remaining developer.

On the other hand, the regulation plate 10 has stirring rollers 8 on both upper and lower surfaces.
A large number of guide plates 37, 37' are installed at regular intervals so as to be oriented at a constant angle with respect to the axial direction of the
have. And below this regulation plate, that is, 1
When the developer moves along 0a, the guide plate 37 causes the developer to move in the direction of arrow 40. Next, the developer is regulated to a certain amount by the cutting plate 11 to form a magnetic brush 9,
The remaining regulated developer is pushed up to the upper surface of the regulation plate 10. The developer pushed up here is transferred along the slope 10b at the top of the regulating plate 10 along the guide plate 37', and falls onto the stirring roller 8 again.

In this regulation plate 10, the guide plates 37, 37' attached to the upper surface 10b and the lower surface 10a are
The respective surfaces are mounted substantially parallel to each other, and the upper and lower surfaces are in a positional relationship that intersects each other. In this way, the developer flows through the guide plates 37 and 3 provided on both the upper and lower sides of the regulation plate 10.
7' as a whole in the direction indicated by arrow 40.

Further, as described above, the spiral roller 12 is rotated by the spiral blade 21 to rotate the roller 12.
Nearby developer can be transported in the width direction.
In FIG. 2, it is transported in the direction of arrow 41.

The direction in which the developer of each of these three is transported in the width direction is not limited to the above-mentioned mode and can be set in any shape depending on the transport ability of each of them. The amount of developer transferred from the back to the front should be the same as the amount transferred from the back to the front. These adjustments are made by the guide section 32 of the stirring roller 8.
The adjustment can be made as desired by changing the number or arrangement of the guide plates 37, 37' in the regulating plate 10, or by changing the distance between the blades 21 in the spiral roller 12.

With the above-described configuration, the present invention can form an efficient circulation path for the developer without stagnation, as well as efficiently agitate the developer and improve the uniformity of the developer within the developing device. It becomes possible to improve the

[Brief explanation of the drawing]

FIG. 1 shows a sectional view of the developing device of the present invention, and FIG. 2 is a perspective view showing the arrangement of a guide mechanism, stirring blades, and spiral rollers. 3... Developing device, 5... Sleeve, 6... Magnet, 8... Stirring roller, 9... Magnetic brush, 10
...Regulation plate, 12...Spiral roller.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A hopper equipped with a toner supply roller and a hopper that rotates in the opposite direction to the rotational direction of the photoreceptor drum,
a developer conveying sleeve equipped with a magnet therein; a brush cutting plate for regulating the length of the magnetic brush formed on the developer conveying sleeve; and a brush cutting plate provided adjacent to the developer conveying sleeve. a plurality of stirring blades each having a tip bent in the direction of rotation, arranged radially around the outer periphery, and a notch provided in each of the stirring blades, and a guide provided by bending one end of the notch. a stirring roller having a spiral passage formed in the axial direction of its outer periphery by a portion; a developer flow regulating plate having a plurality of guide plates oriented in directions forming an acute angle or an obtuse angle, and regulating the movement of the developer in the axial direction in a direction opposite to the direction of movement by the stirring roller; Located upstream in the direction of rotation of the sleeve from the closest position between the sleeve and the agitation roller, it scrapes off the magnetic brush on the surface of the sleeve by its own rotation and conveys the developer in one longitudinal direction. An electrophotographic developing device comprising: a transfer roller; (2) The electrophotographic developing device according to claim 1, wherein the transfer roller is a spiral roller.