JP3129209B2 - Developing device and electrophotographic recording device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a developing apparatus, and an electrophotographic recording apparatus using the same to agitate construction and stable toner density control for stirring the current image agent.

[0002]

2. Description of the Related Art Conventionally, a piezoelectric powder sensor or an optical sensor has been used for detecting the remaining amount of toner in a developing device used in an electrophotographic recording apparatus or in a toner hopper to detect a shortage of toner.

However, these sensors are expensive and
For accurate detection, a cleaning device or the like for the sensor unit is required.

Therefore, it has been proposed that a developing device in which the toner density in the developing device is controlled by a magnetic permeability sensor in a two-component developing system is also used as a sensor for detecting the remaining amount.

According to this, it is not necessary to newly attach a dedicated sensor for detecting the remaining amount of toner, and the cost can be reduced.

FIG. 4 shows that the present applicant has previously filed Japanese Patent Application No. 7-190.
173 shows a developer stirring configuration of the developing device proposed in No. 173;
A first stirring roller 1 disposed in the longitudinal direction, a toner hopper 2 provided on the upstream side of the first stirring roller 1 in the developer conveyance direction, and a toner concentration sensor 3 provided on the downstream side of the developer conveyance direction. And the toner density sensor 3
The developer 4 in the vicinity is stirred by the stirring blade 5 and the toner density is detected while being conveyed by the large-diameter screw 7 formed on the shaft 6.

Reference numeral 8 denotes a plurality of stirring ribs.

[0008]

However, in the above-mentioned conventional configuration, although the toner supplied from the toner hopper is stirred by the stirring blade until it reaches the toner density sensor, it is immediately conveyed onto the toner density sensor. Since the detection of the toner concentration is based only on the stirring by the stirring blades, the stirring performance is insufficient, which causes a variation in the toner concentration.

If the replenished toner is not sufficiently agitated, the rise of the charge amount of the toner is deteriorated, which causes a bad influence and toner scattering at the time of development on the photosensitive member.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a developing apparatus having an improved stirring and conveying structure capable of detecting a more stable and highly accurate toner concentration.

[0011]

In order to solve this problem, the invention of the developing device according to the first aspect of the present invention is to transport toner around an axis from a toner supply port to a downstream side in a transport direction. Forming a spiral stirring member of a small diameter to be formed, subsequently forming a stirring unit for stirring the transported toner, and subsequently forming a spiral stirring member of a large diameter to transport the stirred toner, A stirring roller in which a plate-shaped stirring member for stirring the toner being conveyed by the large-diameter spiral stirring member in a radial direction perpendicular to the axial direction is formed between each spiral of the large-diameter spiral stirring member. If, comprising a toner density sensor for detecting the concentration of toner in the conveying a stirring member having a large-diameter helical shape, the large and agitating member of the small-diameter spiral shape
The stirrer was formed between the stirrer and a spiral stirrer having a diameter.
Things.

[0012] The invention of the developing apparatus according to claim 2, about the axis toward the downstream side from the toner supply port
A small-diameter spiral stirring member for conveying toner
Then, a stirring section for stirring the transported toner is formed.
Large-diameter screw for conveying the stirred toner.
A spiral stirring member is formed, and the large-diameter spiral stirring is performed.
Agitates the toner being transported by the member in the radial direction perpendicular to the axial direction
The plate-shaped stirring member to be replaced with the large diameter spiral stirring member
A stirring roller formed between each spiral, and the large-diameter spiral
That detects the concentration of toner being conveyed by a stirrer
A density sensor, wherein the stirring roller is formed such that the height of the plate-shaped stirring member is gradually reduced toward the toner density sensor, and the plate-shaped stirring member is located at a position facing the toner density sensor. Of the large diameter spiral stirring member.

[0013] The invention of the developing apparatus according to claim 3, about the axis toward the downstream side from the toner supply port
A small-diameter spiral stirring member for conveying toner
Then, a stirring section for stirring the transported toner is formed.
Large-diameter screw for conveying the stirred toner.
A spiral stirring member is formed, and the large-diameter spiral stirring is performed.
Agitates the toner being transported by the member in the radial direction perpendicular to the axial direction
The plate-shaped stirring member to be replaced with the large diameter spiral stirring member
A stirring roller formed between each spiral, and the large-diameter spiral
That detects the concentration of toner being conveyed by a stirrer
A density sensor, wherein the stirring roller is formed such that the height of the plate-shaped stirring member is gradually reduced toward the toner density sensor, and the plate-shaped stirring member is located at a position facing the toner density sensor. The height of the stirring member is formed to be approximately the same as the height of the large-diameter spiral stirring member, and the height of the plate is approximately the same as the height of the large-diameter spiral stirring member. A space is formed on the downstream side in the transport direction of the stirrer-like stirring member between the next large-diameter spiral stirring member.

An electrophotographic recording apparatus according to claim 4.
The invention of claim 1 is the present invention according to any one of claims 1 to 3.
An image device is used.

[0015]

[0016]

According to the first aspect of the present invention, a small-diameter spiral stirring member for conveying toner is formed around an axis from a toner supply port toward a downstream side in a conveying direction, Subsequently, a stirrer for stirring the conveyed toner is formed, and subsequently, a large-diameter spiral stirring member for conveying the stirred toner is formed, and the large-diameter spiral stirring member is conveyed. A stirring roller having a plate-shaped stirring member for stirring the toner in the radial direction perpendicular to the axial direction between the spirals of the large-diameter helical stirring member, and the large-diameter helical stirring member. A toner concentration sensor for detecting the concentration of the toner being conveyed , wherein the small diameter spiral stirring unit is provided.
Between the material and the large diameter spiral stirring member
Is formed.

According to the above aspect, the toner supplied from the toner supply port is provided.
When the toner is conveyed by the stirring roller, a small-diameter screw
It is transported to the stirring section by the swirling stirring member, and
Is roughly agitated with the developer, followed by a large diameter spiral shape
While being stirred by the stirring member and the plate-shaped stirring member.
Is transported toward the toner density sensor,
Due to the difference in specific gravity from the image agent, the toner flows on the surface of the developer
Can be prevented from mixing, and toner and development
Agent can be appropriately mixed. Also, the toner in the developer
Toner density and the toner charging characteristics
Performance can be improved.

The invention according to claim 2 provides a toner supply device.
Apply toner around the axis from the supply port to the downstream in the conveyance direction.
Form a small diameter spiral stirring member to be conveyed,
A stirrer for stirring the conveyed toner is formed.
Large-diameter spiral stirring for conveying the stirred toner
Forming a member and transporting with the large diameter spiral stirring member
Plate agitating the toner in the radial direction perpendicular to the axial direction
The stirring member is placed between the spirals of the large diameter spiral stirring member.
The formed stirring roller and the large diameter spiral stirring member
Density sensor that detects the density of toner being transported by
The stirring roller is formed such that the height of the plate-shaped stirring member gradually decreases toward the toner density sensor, and the plate-shaped stirring member is positioned at a position facing the toner density sensor. The height of the member is formed to be approximately the same as the height of the large diameter spiral stirring member. According to the above aspect, the agitation performance of the developer decreases from large to small and the transport performance increases from small to large toward the toner concentration sensor, so that the toner and the developer can be mixed well and the toner can be smoothly moved on the toner concentration sensor. Can be moved. In addition, the developer remaining near the surface of the toner concentration sensor can be forcibly removed and moved by a plate-shaped stirring member at a position facing the toner concentration sensor, so that new developer always flows on the toner concentration sensor. The developer circulates and prevents the developer from remaining on the toner concentration sensor.

The invention according to claim 3 provides a toner supply device.
Apply toner around the axis from the supply port to the downstream in the conveyance direction.
Form a small diameter spiral stirring member to be conveyed,
A stirrer for stirring the conveyed toner is formed.
Large-diameter spiral stirring for conveying the stirred toner
Forming a member and transporting with the large diameter spiral stirring member
Plate agitating the toner in the radial direction perpendicular to the axial direction
The stirring member is placed between the spirals of the large diameter spiral stirring member.
The formed stirring roller and the large diameter spiral stirring member
Density sensor that detects the density of toner being transported by
The stirring roller is formed such that the height of the plate-shaped stirring member gradually decreases toward the toner density sensor, and the plate-shaped stirring member is positioned at a position facing the toner density sensor. The height of the member is formed so as to be approximately the same as the height of the large-diameter spiral stirring member, and the plate-like member having the same height as the large-diameter spiral stirring member is formed. A space is formed between the stirring member and the next large-diameter spiral stirring member on the downstream side in the conveying direction of the stirring member. According to the above aspect, since the developer is moved and conveyed through this space, it is possible to reduce the load of scraping the developer on the toner density sensor.

[0020] The invention of claim 4, claim 1
Using the developing device according to any one of claims 1 to 3.
It is.

[0021]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a developing device having a toner remaining amount detecting unit according to an embodiment of the present invention.

The developing frame 9 contains a developer 10 composed of a toner and a carrier, and transports the developer 10 while the first stirring roller 11 rotates in the direction of the arrow 12 and stirs from the near side to the far side. .

The second stirring roller 13 rotates in the direction of the arrow 14, and feeds the developer 10 to the developing roller 15 at the same time as it is transported while stirring from the back side to the near side.

The toner density sensor 16 is provided on the developing frame 9 so as to face the first stirring roller 11.

First stirring roller 11 and second stirring roller 13
Are partitioned by a partition plate 17, and the partition plate 17 has cutout portions (not shown) on the front side and the rear side, respectively. The developer 10 is transferred from the roller 13 to the first stirring roller 11 (on the near side), and the developer 10 circulates.

The layer thickness of the developer 10 supplied to the developing roller 15 is regulated by a doctor blade 18.

After being charged by the charger, the photosensitive drum 19 forms an electrostatic latent image on the photosensitive drum 19 by incident light from the optical system.

The toner in the developer 10 supplied to the developing roller adheres to the electrostatic latent image, and development is performed.

FIG. 2 is a sectional view of the developing frame 9 as viewed from the side in the longitudinal direction. A toner hopper 20 is provided on the upstream side in the developer conveying direction in the longitudinal direction of the first stirring roller 11.

The toner hopper 20 supplies toner 22 into the developing device via a toner supply port 21 provided in the developing frame 9.

The toner density sensor 16 is provided on the developing frame 9 downstream of the toner hopper 20 in the developer transport direction and upstream of the longitudinal center of the developing device.

The first stirring roller 11 is provided with a shaft 23 in a portion on the upstream side in the developer conveying direction in the longitudinal direction, and a spiral small-diameter screw 24 outside the shaft 23.
And transports the toner 22 supplied to the inside of the developing device through the.

Downstream of the small-diameter screw 24 in the developer conveying direction, a horizontal blade 25a for moving the developer in a radial direction perpendicular to the axial direction to the outside of the shaft 23, and in a direction parallel to the axis on the front and rear of the horizontal blade 25a. There is a first oblique stirring blade portion 25 provided with an oblique blade 25b for moving the developer and a hole 25c for passing the developer at a part of the horizontal blade 25a.

On the downstream side of the first oblique stirring blade portion 25 in the developer conveying direction, a spiral large-diameter screw 26 is formed outside the shaft 23 at a portion opposed to the toner concentration sensor 16, and between the large-diameter screws 26. There are plate-like developer stirring ribs 27 having different heights.

Further, a second oblique stirring blade portion 28 having the same shape as the first oblique stirring blade portion 25, a large-diameter screw 26a provided outside the shaft 23, and a plate shape for moving the developer in a radial direction perpendicular to the axial direction. And a horizontal stirring blade 29 for moving the developer in a radial direction perpendicular to the axial direction outside the shaft 23 to stir and transport the developer.

The configuration of the large-diameter screw 26 and the plate-shaped developer agitating rib 27 having a different height is such that the portion of the developer agitating rib 27 facing the toner density sensor 16 is the lowest, It gradually becomes higher as it goes in the direction away from front to back.

A plurality of developer stirring ribs 27 are provided between the large-diameter screws 26 at regular intervals in the circumferential direction of the shaft 23.

The developer stirring rib may or may not be provided in the small diameter screw 24.

The operation of the thus constructed developing device will be described with reference to FIG.

Developer 10 contained in developing frame 9
Is transported while being agitated by the first agitating roller 11 in the direction of the arrow 30, and when reaching the inner side in the transport direction, is delivered to the second agitating roller 13 (not shown) and circulates.

At this time, the developer 10 is supplied to the first stirring roller 11
A proper toner density is always maintained by a toner density sensor 16 provided on the developing frame 9 so as to face the toner image.

In the control section, the toner density sensor 16
When the toner density of the developer 10 is determined to be low on the basis of the output of the above, the toner 22 is supplied from the toner hopper 20 into the developing device through the toner supply port 21.

The supplied toner 22 is supplied to the first stirring roller 1.
The developer is conveyed by the first small-diameter screw 24, is roughly stirred with the developer 10 by the first oblique stirring blade 25, and is subsequently delivered to the large-diameter screw 26.

In the large-diameter screw 26, the plate-like developer stirring rib 27 is formed so as to gradually decrease toward the toner density sensor 16. The performance is increased from small to large, the replenished toner 22 is mixed well with the developer 10, and the rising of the charge is improved, so that the toner 22 is smoothly conveyed on the toner density sensor 16.

Therefore, stable toner density control is possible. Further, the developer 10 that has passed through the toner density sensor 16 has the plate-shaped developer stirring rib 27 formed gradually higher, so that the stirring performance is changed from small to large and the conveyance performance is changed from large to small. The toner 10 is smoothly conveyed on the toner density sensor 16, is sufficiently stirred, and is sent to the second stirring roller 13 from the back side.

FIG. 3 is a partially enlarged cross-sectional view showing another embodiment of the present invention, in which the height of a plate-like developer stirring rib 27 b at a position facing the toner density sensor 16 is
The height is almost the same as

By doing so, the developer 10 staying near the surface of the toner density sensor 16 is forcibly removed and moved by the developer stirring rib 27b, and the new developer 10 constantly circulates and moves on the toner density sensor 16. Will be.

Therefore, a stable toner density can be detected by the toner density sensor 16, and stable toner density control can be performed.

A plurality of the developer stirring ribs 27b may be provided on the shaft 23 at a position opposite to the toner density sensor 16, but if provided too much, the transportability of the developer 10 is reduced.

The plate-like developer stirring rib 27b
As shown in FIG. 3, when the tip of the large-diameter screw 26 is disposed between the large-diameter screws 26b and 26c that do not pass over the surface of the toner density sensor 16, the developer remaining on the surface of the toner The tip of the screw 26 and the developer stirring rib 27b are always scraped off, and the output of the toner density sensor 16 is stabilized.

Further, the plate-like developer stirring rib 27b
Represents a space A (non-contact) between the large-diameter screw 26c and the space A (non-contact) at the downstream end in the developer conveyance direction facing the toner density sensor
And is disposed on one of the large diameter screws 26b.

By doing so, the developer 10 is transported from this space, and is smoothly fed without hindering the transport.

Further, since the developer can easily escape from this space, the rotational load can be reduced.

[0055]

As described above, according to the present invention, the toner supply port
When the toner supplied from
To the stirring section with a spiral stirring member with a small diameter on the roller
Conveyed, then roughly stirred with developer in stirring section
After that, a spiral stirring member with a large diameter and a plate-like stirring
Aiming at the toner concentration sensor while being stirred by the stirring member
Transported, the difference in specific gravity between toner and developer
The toner only flows over the surface of the developer, not mixing
Mix the toner and developer appropriately to prevent the phenomenon
Can be. It is also necessary to stabilize the toner concentration in the developer.
And improve the charging characteristics of the toner.
Wear.

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[Brief description of the drawings]

FIG. 1 is a sectional view showing a developing device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a developer stirring and conveying device according to an embodiment of the present invention.

FIG. 3 is a partially enlarged cross-sectional view illustrating a developer stirring and conveying device according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional developer stirring and conveying device.

[Explanation of symbols]

 Reference Signs List 9 developing frame 10 developer 11 first stirring roller 13 second stirring roller 15 developing roller 16 toner density sensor 19 photosensitive drum 20 toner hopper 21 toner supply port 22 toner 23 shaft 25 first oblique stirring blade part 26 large diameter screw 27 development Agent stirring rib

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Sekine 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-58-95765 (JP, A) JP-A-4- 191876 (JP, A) JP-A-4-52672 (JP, A) JP-A-7-253706 (JP, A) JP-A-4-125661 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/08-13/095 G03G 15/08-15/095

Claims (4)

(57) [Claims] 1. A small-diameter spiral stirring member for conveying toner is formed around an axis from a toner supply port toward a downstream side in a conveying direction, and a stirring unit for stirring the conveyed toner is formed. Then, a large-diameter spiral stirring member for conveying the stirred toner is formed, and the large-diameter spiral stirring member stirs the toner being conveyed in a radial direction perpendicular to the axial direction. A stirring roller formed between each spiral of the large-diameter spiral stirring member, and a toner concentration sensor that detects the density of toner being conveyed by the large-diameter spiral stirring member. Equipped with the small diameter spiral shape
Between the stirrer and the large-diameter spiral stirrer.
A developing device comprising a stirring portion . 2. From the toner supply port to the downstream side in the transport direction.
A small-diameter spiral stirrer that conveys toner around the axis
Forming a material, and subsequently stirring the transported toner.
Forming a stirring section, and subsequently conveying the stirred toner
Forming a large diameter spiral stirring member, the large diameter spiral
The toner being conveyed by the agitating member in a radial direction perpendicular to the axial direction.
The large-diameter spiral stirring member is used to stir the plate-like stirring member in the horizontal direction.
A stirring roller formed between each spiral of the stirring member;
Of the toner being conveyed by the spiral stirring member
And a stirring roller,
The height of the plate-shaped agitating member is formed so as to gradually decrease toward the toner density sensor, and the height of the plate-shaped agitating member at a position facing the toner density sensor is set to the large diameter spiral. A developing device characterized in that it is formed so as to have a height substantially equal to the height of a stirring member having a shape. 3. From the toner supply port toward the downstream side in the transport direction.
A small-diameter spiral stirrer that conveys toner around the axis
Forming a material, and subsequently stirring the transported toner.
Forming a stirring section, and subsequently conveying the stirred toner
Forming a large diameter spiral stirring member, the large diameter spiral
The toner being conveyed by the agitating member in a radial direction perpendicular to the axial direction.
The large-diameter spiral stirring member is used to stir the plate-like stirring member in the horizontal direction.
A stirring roller formed between each spiral of the stirring member;
Of the toner being conveyed by the spiral stirring member
And a stirring roller,
The height of the plate-shaped agitating member is formed so as to gradually decrease toward the toner density sensor, and the height of the plate-shaped agitating member at a position facing the toner density sensor is set to the large diameter spiral. It is formed so as to have the same height as the height of the stirrer having a shape, and the following in the transport direction downstream of the plate-shaped stirrer having the same height as the height of the spiral stirrer having the large diameter. A developing device, wherein a space is formed between the stirring member and a large-diameter spiral stirring member. 4. An electrophotographic recording apparatus using the developing device according to claim 1.