JP3187165B2 - Doctor processing method and developing device using this doctor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a doctor for regulating the amount of developer on a developing roller in a developing apparatus using a one-component or two-component developer, such as an electrophotographic copying machine or a laser printer.

[0002]

2. Description of the Related Art In a conventional developing device, a developing roller in a developing tank magnetically attracts the developer, and the developer rises on the surface of the developing roller. Is regulated. Then, the developer regulated by the doctor is conveyed by the rotation of the developing roller, and slidably contacts the photosensitive member to develop the electrostatic latent image.

Since this doctor is formed by stamping a flat plate, as shown in FIG.
During punching, arc-shaped drooling, burrs, and the like occur due to gaps between the molds 3 and 4 during punching.

However, in order to make the amount of the developer on the developing roller uniform, the straightness of the doctor is important.

[0005] Therefore, as shown in FIG.
Was polished along the line BB 'to improve the straightness of the doctor.

[0006]

However, in the conventional doctor 1 polishing method, since the grinding is performed perpendicular to the side surface of the doctor 1 , the tip 2 of the doctor 1 has no arc formed at the time of punching. And developing roller rotation
The upstream side is the edge with respect to the direction . for that reason,
The stress on the developer has increased, shortening the life of the developer, and resulting in uneven image quality. In recent image forming apparatuses, high image quality is demanded, and developing conditions for determining the image quality are becoming severe, and the dimensional accuracy of a doctor that regulates the amount of developer on a developing roller is improved. Was also an important issue.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a doctor of a developing device capable of improving image quality without giving stress to a developer.

[0008]

According to the first and second aspects of the present invention, as shown in FIGS. 1 and 6, a developing roller 16 is rotatably provided in a developing tank 12 and a developing roller 16 on the developing roller 16 is provided. In a developing device in which a doctor 31 for regulating the spike of the agent is provided with a gap from the developing roller 16, the doctor 31 is formed by stamping a flat plate by pressing to form a tip 33 in an arc shape. leaving the arc 34, the Rukoto polished obliquely in a direction away from the developing roller 16 from the upstream side toward the downstream side with respect to the developing roller rotation direction front end portion 33, continuous with the portion of the arc 34
The inclined portion is formed .

[0009]

[Action] In the above problem solving means, when the doctor 31 regulates the magnetic brush of the developer on the developing roller 16, the circular arc 3 4 formed in the distal end portion 33 of the doctor 31, less stress on the developer And the life of the developer is extended.

[0010]

1 is a sectional view showing a developing device according to an embodiment of the present invention, FIG. 2 is a perspective view of a first stirring roller, FIG. 3 is a perspective view of a second stirring roller, and FIG. 4 is a perspective view of an agitator. 5 shows a doctor, (A) is a plan view thereof, (B) is a side view thereof, FIG. 6 is an enlarged view of a distal end portion of the doctor, and FIG. 7 is a sectional view of a carrier.

As shown in FIG. 1, the developing device of the present embodiment includes a developing tank 12 arranged opposite to a photoreceptor 11 and a toner replenishing tank 13 disposed above the developing tank 12.

A toner supply port 1 is provided above the developing tank 12.
4, and an opening / closing lid 15 for opening and closing the toner supply port 14.

In the developing tank 12, a developing roller 16 is arranged in proximity to the photoconductor 11, and first and second stirring rollers 17, 1 are directed from the developing roller 16 toward the toner supply port 14.
8 are sequentially arranged, and the first and second stirring rollers 17 and 18 are arranged.
A transfer magnet roller 19 is disposed above the space between
An agitator 20 is provided below the toner supply port 14.

A toner replenishing roller 21 is rotatably mounted in the toner replenishing tank 13, and the toner replenishing port 14 is provided therein.
Replenish toner from.

The developing roller 16 is externally fitted to a support shaft 22 rotatably supported by the developing tank 12, and is fixed to the developing tank 12 by a magnet 23. The developing roller 16 is rotatably fitted to the magnet 23. The sleeve 24 is driven to rotate counterclockwise by a motor.

The first stirring roller 17 is, as shown in FIG.
A roller shaft 17a rotatably supported by the developing tank 12,
A large number of fins 25 project perpendicularly to the roller shaft 17a.

The second stirring roller 18 is, as shown in FIG.
A roller shaft 18a rotatably supported by the developing tank 12,
A large number of elliptical fins 26 are attached to the roller shaft 18a at an angle.

As shown in FIG. 4, the agitator 20 includes a shaft 20a rotatably supported by the developing tank 12, and two fins 27 projecting in a tangential direction of the shaft 20a.

The transport magnet roller 19 is externally fitted on a support shaft 28 rotatably supported by the developing tank 12 and fixed to the developing tank 12, and is rotatably externally fitted on the magnet body 29. And a sleeve 30.

Each of the rollers 16 to 20 is rotationally driven by a motor in the direction of the arrow shown in FIG.

Above the developing roller 16, a doctor 31 for regulating the height of the spike of the developer on the developing roller 16 is provided.
Is arranged.

As shown in FIG. 5, the doctor 31 is a flat plate punched out by press working, and is screwed to the developing tank 12 through a hole 32. Then, as shown in FIG. 6, the distal end portion 33 for regulating the magnetic brush of the developing roller 16 side of the developer, leaving a circular arc 3 4 formed at the time of punching,
The shape is inclined in a direction away from the developing roller 16 from the upstream side to the downstream side with respect to the rotation direction of the developing roller.

In FIG. 1, reference numeral 35 denotes a first flow plate, 36 denotes a second flow plate, and 37 denotes a toner density sensor.

In the above configuration, the toner supplied from the toner supply tank 13 through the toner supply port 14 is pulverized by the agitator 20 and sent to the second stirring roller 18.

Then, the developer and the toner are stirred by the second stirring roller 18, and the toner rubs against the carrier in the developer to be charged to the polarity opposite to that of the electrostatic latent image. Is drawn up by the transport magnet roller 19 along the baffle plate 35, and agitated by the agitator 20 along the second flow plate 36.
In the direction of The remaining developer is the first stirring roller 1
Flow towards 7 and stir further.

Then, the developer sent to the developing roller 16 magnetically adheres to the sleeve 24 to be in a standing state to form a magnetic brush, and is conveyed toward the photosensitive member 11 by the rotation of the sleeve 24. You.

On the way, the developer is smoothly moved without being stressed by the doctor 31, and is conveyed to the photoconductor 11 while the height of the magnetic brush is regulated, and the electrostatic latent image on the photoconductor 11 is Is developed.

At this time, the amount of the developer on the developing roller 16 is determined by adjusting the gap between the doctor 31 and the developing roller 16. Usually, this gap is 0.
5 to 2.0 mm, adjustment error ± 0.025 to 0.05
mm is common. However, this value is becoming severer year by year as the copy image quality becomes higher.

Incidentally, in order to regulate the spikes of the developer, the gap between the doctor 31 and the developing roller 16 must be adjusted, and the straightness in the longitudinal direction of the doctor tip 33 is important. In order to improve the straightness, the tip portion 33 is polished.

[0030] That is, when punching a flat plate with a press, an arc shape is generated by the gap of the die as shown in FIG. Conventionally, as shown in FIG.
This arc shape was almost eliminated by polishing . Therefore, the carrier 38 in the developer is
As described above, the coating material 40 is peeled off by the stress of the doctor 31 and the like, and the life of the developer varies depending on the shape of the doctor 31. Therefore, the life of the developer largely depends on the <br/> presence of an arc shape.

Therefore, in this embodiment, when the distal end portion 33 of the doctor 31 is polished, polishing is performed up to the line AA 'shown in FIG. 6 so as to leave the arc shape 34 as much as possible.

Then, a test was conducted to determine whether the coating material 40 on the surface of the carrier 38 was peeled off due to aging of the shape of the distal end portion of the doctor 31, and the results are shown in FIG. In the figure,
A is a conventional doctor, B is a doctor of this embodiment, and C is an unpolished doctor after punching.

In the analysis of the peeling of the coating material 40 of the carrier 38, measurement is performed by a fluorescent X-ray analyzer. When an X-ray fluorescence analyzer irradiates a substance with X-rays, part of the X-rays absorbed by the substance is emitted as fluorescent X-rays having a specific energy (wavelength) depending on the type of each element. The type and amount of the element contained in the substance can be determined by measuring the X-ray wavelength and the intensity of the fluorescent X-ray by analyzing the fluorescent X-ray.

The developer after 20,000 sheets, 50,000 sheets, and 100,000 sheets after copying is sampled by aging, the toner is removed by blow-off of the developer, and only the carrier 38 is left. The element analysis of the carrier 38 is performed by the apparatus. Then, the amounts of Fe and Si of the core material 39 and the coating material 40 of the carrier 38 were measured, and the amount of the coating material 40 (Si / F
e) Calculate the ratio.

As shown in FIG. 8, for B and C, almost the same good results were obtained, but for A, the peeling of the coating material 40 of the carrier 38 was large.

As described above, the distal end portion 33 of the doctor 31
However, by polishing while leaving the arc 34 formed at the time of punching shown in FIG. 6, stress applied to the developer is reduced, and peeling of the coating material 40 of the carrier 38 is reduced, thereby extending the life of the developer. be able to.

Conventionally, the straightness of the doctor is 0.05 mm with respect to the dimension 467 mm in the longitudinal direction of the doctor.
However, in the present embodiment, the straightness of the doctor is improved to 0.03 mm, and the accuracy of the doctor can be improved, so that it is possible to cope with the setting of severe developing conditions and obtain a high-quality copy. be able to.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention.

[0039]

As is apparent from the above description, according to the first and second aspects of the present invention, the distal end of the doctor is polished while leaving an arc formed at the time of punching a flat plate . In addition, the stress applied to the developer is reduced, and the life of the developer can be extended. And compared to polishing the entire tip
In addition, the minimum required polishing is required, and the processing time is reduced.
Improve productivity.

Further, since the straightness of the doctor in the longitudinal direction is improved and the dimensional accuracy of the doctor is improved, the amount of the developer on the developing roller can be regulated uniformly. Therefore, there is an excellent effect that it is possible to cope with a severe development condition setting and to obtain a high-quality copy.

[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 perspective view of a first stirring roller.

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

FIG. 4 is a perspective view of an agitator.

5A is a plan view of a doctor, and FIG. 5B is a side view of the doctor.

FIG. 6 is an enlarged view of the distal end of the doctor.

FIG. 7 is a sectional view of a carrier.

FIG. 8 is a view showing a peeling ratio of a coating material of a carrier due to aging with respect to a doctor shape.

FIG. 9 is an enlarged view of the distal end of the doctor at the time of punching.

FIG. 10 is an enlarged view of the tip of a conventional doctor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Photoreceptor 12 Developing tank 16 Developing roller 31 Doctor 33 Tip part 34 Arc 38 Carrier 39 Core material 40 Coating material

Claims (2)

(57) [Claims] 1. A developing roller rotatably provided in a developing tank.
A flat plate is punched out by pressing at a doctor of a developing device provided with a gap between the developing roller and the developing roller so as to regulate the rising of the developer on the developing roller.
The tip on the upstream side with respect to the rolling direction
Remaining from the upstream in the rotation direction to the downstream, leaving an arc
Polish the tip diagonally in the direction away from the image roller.
And a doctor processing method. 2. A developing tank having a developing roller rotatably provided therein.
And a doctor for restricting the rising of the developer on the developing roller.
Developing device provided with a gap with the developing roller
The method according to claim 1, wherein the doctor is used as the doctor.
A doctor machined by the method is used.
The upstream end of the tip of the developing roller with respect to the rotation direction of the developing roller is
It is formed in an arc shape, and the downstream side continues to this arc portion
The part inclined in the direction away from the developing roller is
And the tip of the doctor has a predetermined gap.
The doctor so that it faces the developing roller.
A developing device attached to the developing tank.
Place.