JPH05289498A - Developing device - Google Patents

Abstract

PURPOSE:To smoothly recover and supply a developer from/to a magnet roller. CONSTITUTION:The axial direction of a stirring roller 22 is perpendicular to the axial direction of the magnet roller 21. The stirring roller 22 has the attachment of an increasingly broadened plate 28 in one end, and a conical spiral blade 29 to the other side, and is notched/recessed into a circular-arc shape along the circumference of the magnet roller 21, on the central part. The other side of the stirring roller 22 is arranged on the side of the pole for drawing a developer N2, of the magnet roller 21. The developer is recovered from the magnet roller 21 by the plate 28 of the stirring roller 22, and scooped up by the spiral blade 29 and carried to the pole. N2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for visualizing a latent image formed on a photoreceptor or the like with a developer, and more particularly to improving a developer stirring mechanism.

[0002]

2. Description of the Related Art As shown in FIG. 10, a developing device in an image forming apparatus such as a copying machine has a developing tank 1 in which a magnet roller 3 facing a photoconductor 2 and a stirring roller 4 are rotatably mounted. .. A toner supply port 5 is provided above the stirring roller 4.
Is formed, and the toner replenishing tank 6 is mounted on the upper part thereof.

Magnet roller 3 and stirring roller 4
Are rotated by being interlocked by a motor through gears, belts and the like.

The developing tank 1 also includes a toner concentration sensor 7
Further, a doctor 8 is mounted, and a toner replenishing roller 9 is rotatably arranged near the toner replenishing port 5 of the toner replenishing tank 6.

The developer D in the developing tank 1 is attracted to the magnet roller 3 by the magnetic force of the magnet inside, and is supplied to the photoconductor 2 while the spikes are regulated by the doctor 8.
Toner is attached to the electrostatic image to form a visible image.

The toner concentration of the developer is detected by the toner concentration sensor 7, and when the toner concentration is lowered, the toner replenishing roller 9 is rotationally driven to drop the toner from the toner replenishing tank 6. The toner supplied to the developing tank 1 is stirred with the developer by the rotation of the stirring roller 4.

Here, the stirring roller 4 is, as shown in FIG.
A stirring blade 11 made of resin is externally fitted and fixed to the metal shaft 10, and the stirring blade 11 includes an elliptical blade 11a inclined with respect to the shaft 10 and a blade 11b perpendicular to the shaft 10.

The elliptical blade 11a performs stirring in the axial direction (longitudinal direction of the developing tank), and the vertical blade 11b performs stirring in the radial direction.

[0009]

When the shaft 10 is arranged parallel to the magnet roller 3 like the conventional stirring roller 4, the stirring in the axial direction is performed by the inclined blades 11a, so that the developer Stirring unevenness occurs due to one-sided deviation in the axial direction or the pitch of the blades 11a. Therefore, in halftone copying, image unevenness may occur due to uneven pitch of the developer.

Further, since the drive of the magnet roller 3 and the agitating roller 4 are interlocked with each other, it takes a short time for the toner replenished from the toner replenishing tank 6 to reach the magnet roller 3, and the toner is sufficiently agitated with the developer. Can't
Problems such as fogging and toner scattering may occur.

Further, in the stirring state in the toner replenishing cycle after the toner empty, a large amount of toner is continuously replenished from the toner replenishing tank 6, so that the toner reaches the magnet roller 3 without being sufficiently stirred with the developer. Then, the toner is scattered from the magnet roller portion.

In view of the above, it is an object of the present invention to provide a developing device capable of uniformly agitating the developer not only in the radial direction but also in the axial direction and smoothly supplying and collecting the developer to and from the magnet roller. ..

[0013]

As shown in FIGS. 1 and 2, a developing tank 20 is provided with a magnet roller 21 and a plurality of agitating rollers 2 arranged side by side.
2, and the roller shaft direction of the stirring roller 22 is perpendicular to the roller shaft direction of the magnet roller 21, and the stirring roller 22 has a central portion of the magnet roller 21.
It is a concave shape that is cut out in an arc shape along the circumference of.

The agitating roller 22 is, as shown in FIG.
A divergent flat plate 28 is attached to one side, a conical spiral blade 29 is attached to the other side, and the other side of the stirring roller 22 is arranged on the developer pumping pole side of the magnet roller 21.

The problem solving means according to claim 3 is as shown in FIGS.
As described above, the roller axis direction of the plurality of juxtaposed stirring rollers 50 is perpendicular to the roller axis direction of the magnet roller 21, and the stirring roller 50 has a large diameter on one side and a small diameter on the other side. The other side of 50 is arranged on the doctor side.

In the means for solving the problem according to the fourth aspect, the shielding members 23 and 51 are arranged between the stirring rollers 22 and 50, and the driving unit 36 that integrally rotates the stirring rollers 22 and 50.
Is provided.

[0017]

In the means for solving the problems according to claims 1 and 2, when the stirring roller 22 rotates, the developer is conveyed while being stirred by the stirring roller 22.

At this time, the flow of the developer is blocked by the shielding member 23 between the adjacent stirring rollers 22, but the developer outside the stirring roller 22 circulates along the rotation direction of the stirring roller 22. I will do it.

On the other hand, the developer released from the magnet roller 21 is smoothly collected from the magnet roller 21 by the flat plate 28. This developer is mixed with the circulating developer and is conveyed by the spiral blade 29 to the scooping pole N2 of the magnet roller 21. Then, the developer is adsorbed by the scooping pole N2 of the magnet roller 21,
Used for development.

According to the third aspect, the developer is conveyed while being stirred by the stirring roller 50. At this time, the shielding members 51a and 51a are not provided between the adjacent stirring rollers 50.
Although the flow of the developer is blocked by b, the stirring roller 5
The developer outside 0 is circulated along the rotation direction of the stirring roller 50.

On the other hand, the developer released from the magnet roller 21 is smoothly collected from the magnet roller 21 by the large diameter portion of the stirring roller 50.

Then, the circulating developer and the developer recovered from the magnet roller 21 are mixed and supplied to the magnet roller 21 from the small diameter portion of the stirring roller 50.

At this time, the developer attracted to the magnet roller 21 is not scraped off by the stirring roller 50.

[0024]

【Example】

(First Embodiment) FIG. 1 is a longitudinal sectional view of a developing device showing a first embodiment of the present invention, FIG. 2 is a plan view of the developing device, FIG. 3 is a perspective view of a stirring roller, and FIG. 4 is a second stirring roller. FIG. 5 is a plan view of the drive unit of the stirring roller, and FIG. 6 is a front view of the drive unit of the developing device.

The developing device of this embodiment is as shown in FIGS.
The developing tank 20 is internally provided with a magnet roller 21 and a stirring roller 22 arranged in two rows. The roller axis direction of the stirring roller 22 is perpendicular to the roller axis direction of the magnet roller 21. Shielding member 2 between rollers 22
Three are arranged.

The magnet roller 21 is arranged in parallel to face the photoconductor 24, and is composed of a cylindrical sleeve made of a conductive non-magnetic metal and a plurality of magnets fixedly arranged therein. Rotating shaft 25 attached to sleeve
Is rotatably supported on the side wall of the developing tank 20.

The magnetic roller 21 has five magnetic poles, and the magnetic poles are arranged from the upstream side in the conveying direction of the developer D to N2.
S1, N1, S2, N3. And N2 pole and S
The doctor 26 is disposed above the one pole.
The N2 pole is the developer drawing pole and the N3 pole is the developer releasing pole.

The stirring roller 22 arranged on the magnet roller side has a concave shape in which the central portion is cut out in an arc shape along the circumference of the magnet roller 21, and the radius of curvature of the arc portion is Magnet roller radius +2 to 10
mm.

The stirring roller 22 is, as shown in FIG.
On the lower side of the roller shaft 27, a flat plate 28 having a diverging shape is formed.
The conical spiral blade 29 is attached to the upper side of the roller shaft 27, and the stirring blade 29 is arranged on the developer drawing pole N2 side of the magnet roller 21.

The stirring roller on the side of the developing tank wall is the second stirring roller 30. As shown in FIG. 4, a set of three blades projecting perpendicularly to the roller shaft 31 are circumferentially offset and arranged. Has been. The roller shafts 27 and 31 are rotatably supported on the upper and lower walls of the developing tank 20.

The shielding member 23 is vertically provided between the upper and lower walls of the developing tank 20 and has a length which is approximately half the outer diameter of each stirring roller 22 and 30 to partition the stirring rollers 22 and 30. is doing. Then, the shielding member 23 of the stirring rollers 22 and 30
On the side not partitioned by, the flow of the developer shown by the arrow in FIG. 2 is formed.

A toner replenishing tank is installed above the second agitating roller side of the developing tank 20. A toner replenishing port 32 is formed between the developing tank 20 and the developing tank 20, and the toner replenishing roller rotates there. It is arranged freely.

As shown in FIGS. 5 and 6, the magnet roller 21 and the stirring rollers 22 and 30 integrally rotate the developing drive unit 35 for rotating the sleeve of the magnet roller 21 and the stirring rollers 22 and 30, respectively. A stirring drive unit 36 is provided, and the stirring drive unit 36 is driven in conjunction with the developing drive unit 35.

The developing drive unit 35 includes the magnet roller 21.
The drive shaft of the motor is connected to one end of the rotary shaft 25 through a coupling. A gear 37 is attached to one end of the rotary shaft 25.

The agitation drive unit 36 includes the roller shafts 27 and 31.
Drive pulley 38 mounted by parallel pins on the upper end of the
A timing belt 40 wound around each drive pulley 38 via an idle pulley 39; a worm wheel 41 integrally attached to the drive pulley 38 on a roller shaft 27 of the stirring roller 22 on the drive input side; and a worm wheel. It comprises a worm 42 meshed with 41 and a drive gear 43 coaxial with the worm 42.

The drive gear 43 is meshed with the gear 37 of the rotary shaft 25 of the magnet roller 21, the drive force of the motor is transmitted from the gear 37 to the stirring drive unit 36, and the rotary force is transmitted to the roller shafts 27 and 31. Will be done. As a result, the stirring rollers 22 and 30 are all rotated clockwise.

In the above structure, when the motor is driven during the image forming operation, the rotary shaft 25 is rotated and the sleeve of the magnet roller 21 is rotated. Along with this, the driving force is transmitted from the gear 37 of the rotating shaft 25 to the driving gear 43, the worm 42 rotates, and the worm wheel 41 rotates.

As the drive pulley 38 integrated with the worm wheel 41 rotates, the timing belt 4
0 rotates, each drive pulley 38 rotates integrally, and all the stirring rollers 22 and 30 rotate clockwise.

Then, the developer D is mixed with the agitating rollers 22, 3
It is conveyed while being stirred by 0. At this time, the flow of the developer is blocked by the shielding member 23 between the adjacent agitating rollers 22, but the developer outside the agitating rollers 22 and 30 does not move along the rotating direction of the agitating rollers 22 and 30. It circulates clockwise.

Since the toner supplied from the toner replenishing tank rides on the circulating developer flow, it is circulated once without being conveyed in the direction of the magnet roller 21 and sufficiently stirred with the developer during this period. It

On the other hand, the developer released by the N3 pole of the magnet roller 21 is applied to the magnet roller 2 by the flat plate 28.
It is recovered smoothly from 1. When the circulating developer reaches the stirring roller 22 on the magnet roller 21 side, it is mixed with the developer collected from the magnet roller 21 and is lifted up by the spiral blade 29. Then, it is attracted to the sleeve by the scooping pole N2 of the magnet roller 21 and is used for development.

As described above, by making the stirring roller perpendicular to the magnet roller, it is possible to sufficiently stir the developer not only in the radial direction but also in the longitudinal direction of the developing tank, as compared with the conventional parallel case. You can

Moreover, since the shielding member is arranged between the agitating rollers, the developer can be circulated in the developing tank and the developer can be agitated efficiently.

Further, since the stirring roller is cut into an arc shape, it is possible to smoothly and efficiently supply the developer to the magnet roller and recover the developer from the magnet roller.

(Second Embodiment) FIG. 7 is a vertical sectional view of a developing device showing a second embodiment of the present invention, and FIG. 8 is a plan view of the developing device.
FIG. 9 is a perspective view of the stirring roller.

In the developing device of this embodiment, as shown in FIGS. 7 and 8, in the developing tank 20, conical stirring rollers 50 having a large diameter on one side and a small diameter on the other side are arranged side by side in two rows. The other side of the roller 50 is arranged on the doctor 26 side, and each stirring roller 5
Between 0, the shielding members 51a and 51b are provided.

As shown in FIG. 9, the stirring roller 50 has four blades 53, which are perpendicular to the roller shaft 52, attached at 90 ° intervals and are stacked in three stages. Then, the height of the blade 53 on one side is high, and becomes lower toward the other side.

Among the stirring rollers 50, those arranged on the magnet roller side have the small-diameter blades on the upper side, and those arranged on the developing tank wall side have the large-diameter blades on the upper side.

The shielding members 51a and 51b are erected between the upper and lower walls of the developing tank 20 and arranged in the longitudinal direction.
1a is inclined along the outer shape of the stirring roller 50, and a shielding member 51b arranged in a direction perpendicular to this is parallel to the roller shaft 52.

The other structure is the same as that of the first embodiment.

In such a structure, the developer is conveyed while being stirred by the stirring roller 50. At this time, the shielding member 51 is provided between the adjacent stirring rollers 50.
Although the developer flow is blocked by a and 51b, the developer outside the stirring roller 50 circulates clockwise along the rotation direction of the stirring roller 50.

On the other hand, the developer released by the N3 pole of the magnet roller 21 is smoothly recovered from the magnet roller 21 by the large-diameter blades 53 of the stirring roller 50.

Then, the circulating developer and the developer collected from the magnet roller 21 are mixed, adsorbed on the sleeve by the scooping pole N2 of the magnet roller 21, and provided for development.

At this time, since the small-diameter blades of the stirring roller 50 are arranged on the pumping pole side of the magnet roller 21, the developer attracted to the magnet roller 21 is not scraped off by the stirring roller 50.

Therefore, the stirring roller can smoothly collect the developer from the magnet roller, and the stirring roller can prevent the supply of the developer from being disturbed by the stirring roller.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

The arrangement of the stirring rollers is not limited to that shown in the embodiment, and may be arranged in rows or columns. Alternatively, the stirring roller and the magnet roller may be separately driven, and only the stirring roller may be driven when replenishing the toner.

In the second embodiment, if the doctor is below the developing tank, the small diameter side of the stirring roller faces downward.

[0059]

As is apparent from the above description, according to the first and second aspects of the present invention, the stirring roller is perpendicular to the magnet roller, so that the stirring roller can be arranged only in the radial direction as compared with the conventional parallel roller. Instead, the developer can be sufficiently stirred in the longitudinal direction of the developing tank.

Further, since the stirring roller is cut into an arc shape, it is possible to smoothly and efficiently supply the developer to the magnet roller and recover the developer from the magnet roller.

According to the third aspect, the stirring roller which is perpendicular to the roller axis direction of the magnet roller has one side having a large diameter and the other side having a small diameter, and the other side of the stirring roller is arranged on the doctor side. The developer can be smoothly collected from the magnet roller by the large diameter side of the stirring roller, and the developer can be scraped off from the magnet roller because the developer is supplied to the magnet roller by the small diameter side of the stirring roller. Can be prevented.

According to the fourth aspect, since the shielding member is arranged between the agitating rollers and the agitating rollers are integrally rotated, the developer can be circulated in the developing tank. Stirring can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a developing device showing a first embodiment of the present invention.

FIG. 2 is a plan view of a developing device.

FIG. 3 is a perspective view of a stirring roller.

FIG. 4 is a perspective view of a second stirring roller.

FIG. 5 is a plan view of a drive unit of a stirring roller.

FIG. 6 is a front view of a driving unit of the developing device.

FIG. 7 is a vertical sectional view of a developing device showing a second embodiment of the present invention.

FIG. 8 is a plan view of the developing device.

FIG. 9 is a perspective view of a stirring roller.

FIG. 10 is a sectional view of a conventional developing device.

FIG. 11 is a perspective view of a conventional stirring roller.

[Explanation of symbols]

 20 Development Tank 21 Magnet Roller 22,50 Stirring Roller 23,51a, 51b Shielding Member 26 Doctor 28 Flat Plate 29 Spiral Blade 36 Stirring Drive Unit N2 Pumping Pole

Claims (4)

[Claims] 1. A developing tank is internally provided with a magnet roller and a plurality of agitating rollers arranged in parallel, the roller axis direction of the agitating roller is perpendicular to the roller axis direction of the magnet roller, and the agitating roller is The developing device is characterized in that the central portion has a concave shape that is cut out in an arc shape along the circumference of the magnet roller. 2. The stirring roller according to claim 1, wherein a divergent flat plate is attached to one side, a conical spiral blade is attached to the other side, and the other side of the stirring roller is a magnet roller-side developer scooping pole side. A developing device characterized in that the developing device is arranged in. 3. A developing tank is internally provided with a magnet roller and a plurality of agitating rollers arranged in parallel, a doctor is disposed in the vicinity of the magnet roller, and the roller axis direction of the agitating roller is the roller axis of the magnet roller. It is perpendicular to the direction, the stirring roller has a large diameter on one side and a small diameter on the other side,
A developing device in which the other side of the stirring roller is disposed on the doctor side. 4. The developing device according to claim 1, wherein:
A developing device, in which a shielding member is arranged between the stirring rollers, and a drive unit for integrally rotating the stirring rollers is provided.